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2007 ASME/IEEE International Conference on Mechatronic and Embedded Systems and Applications

2007;():3-11. doi:10.1115/DETC2007-34408.

This paper proposes a simultaneous localization technique of mobile robot and pedestrian in ubiquitous sensor network. For the robot localization, a dead-reckoning system is developed wherein odometer, magnetic compass, and heading angle rate sensor are used. The novelty of dead-reckoning system developed in this paper is that it does not use acceleration in motion dynamic equation. Since the dead-reckoning system does not use linear acceleration, the system is not affected by high frequency noise, which is usually contained in the accelerometer measurement. For the pedestrian tracking, ubiquitous sensor network such as IEEE 802.15.4 is used. In this paper, it is also assumed that the relative direction of the pedestrian from the mobile robot is measured on the robot platform. Extended Kalman filter is used to integrate the sensor measurements. Simulation results will be presented to demonstrate the superiority of the proposed simultaneous localization technique.

Topics: Robots , Robotics
Commentary by Dr. Valentin Fuster
2007;():13-20. doi:10.1115/DETC2007-34409.

An operation states observer for a wheelchair system is extended to three dimensions in this paper. This new observer incorporates a three-axis accelerometer allowing a user to estimate more precise information on terrain condition. To design this observer, first, a model dynamics illustrating the two-dimensional relationship between the gravity and the motion of a wheelchair on a slope is derived. Experimental results verify our derivation of equations. Then, the dynamics is simplified and used in the design of the extended observer. Since the dynamics itself and the output of that have nonlinear characteristics, the extended kalman filter design algorithm is employed. By simulation, the stability and effectiveness of the application is verified.

Topics: Wheelchairs
Commentary by Dr. Valentin Fuster
2007;():21-30. doi:10.1115/DETC2007-34412.

This paper presents a new platform with a team of lab-scale networked mobile robotic manipulators (SumoMote) which merges a mobile manipulator with wireless mobile sensor networks. Many existing platforms built for mobile manipulation are big and expensive. Our SumoMote is built small and inexpensive for applications where quantity is more important than size. The hardware and software of the SumoMote will be described. Then two application scenarios will be presented to illustrate SumoMote’s capability in mobile sensor networks and how the added manipulator can help.

Commentary by Dr. Valentin Fuster
2007;():31-39. doi:10.1115/DETC2007-34701.

This paper presents a method for building a probability grid map for autonomous mobile robots with ultrasonic sensors using a footprint association filter (FAF). The method is based on evaluating the possibility that the acquired sonar data are all reflected by the same object. The FAF is able to associate data points with each other. Data affected by specular reflection are not likely to be associated with the same object, so they are excluded from the data cluster by the FAF, thereby improving the reliability of the data used for the probability grid map. Since the corrupted data are not used to update the probability map, it is possible to build a good quality grid map even in a specular environment. The FAF was applied to the Bayesian probability models, which are typical models used to build grid maps, to verify its effectiveness. Experimental results were also obtained using a mobile robot in a ubiquitous home environment.

Commentary by Dr. Valentin Fuster
2007;():41-47. doi:10.1115/DETC2007-35806.

This paper describes a relative motion emulating robotic system (RMERS) which is made up with a vision navigation (VISNAV), a novel method for proximity navigation and mobile Stewart platforms, parallel manipulators to have six degrees of freedom. The RMERS is a ground-based test bed for aerial refueling and enables already simulated results to physically demonstrate their performance in a ground level. The scope of REMES can reach any relative dynamical system which requires experimental tests. This paper presents theoretical introduction prior to making REMES tangible in the lab. The VISNAV system and the kinematics and dynamics of the Stewart platform will be shortly introduced and dynamical mapping from aerial refueling to mobile Stewart platforms will be given. Finally, some numerical results are simulated.

Topics: Motion , Robotics
Commentary by Dr. Valentin Fuster
2007;():49-56. doi:10.1115/DETC2007-34439.

With the adoption of FlexRay, the time triggered paradigm has been widely accepted by the automotive industry as a means to tackle the requirements of future automotive electronics. However, when compared with traditional event-triggered systems like CAN, the benefits of higher reliability come at the cost of increased complexity during system design. In fact, to support the development of these systems adequate tool-support will be mandatory. In this paper we discuss the requirements and concepts for and present an implementation of a test and diagnosis toolset for FlexRay-based automotive distributed networks. Next to data monitoring and recording, this toolset provides facilities for fault injection and replay. Hence, the presented implementation is tailored for an embedded test and fault diagnosis and will enable an assessment of the reliability and dependability of future automotive solutions.

Commentary by Dr. Valentin Fuster
2007;():57-63. doi:10.1115/DETC2007-35369.

Knowledge of task execution time is a key requirement when determining the most appropriate scheduler algorithm (and scheduler parameters) for use with embedded systems. Unfortunately, determining task execution times (ETs) can be a challenging process. This paper introduces a novel system architecture which is based on two components (i) the main processor (MP) platform, containing the time-triggered (co-operative) scheduler and task code, and (ii) a second processor, executing a “scheduler agent” (SA). In the experiments described in this paper, the MP contains an instrumented scheduler and, during a “tuning” phase, the SA measures — on line — the ET of each task as it runs. The measured values are then used to fine tune the task schedule in an attempt to ensure that (i) all task constraints — such as deadline and jitter — are met (ii) power consumption is reduced. After the tuning phase is completed the SA continues to monitor the MP and can take appropriate action in case of errors. In the paper, the effectiveness of the proposed architecture is demonstrated empirically by applying it to a set of tasks that represent a typical embedded control system.

Commentary by Dr. Valentin Fuster
2007;():65-71. doi:10.1115/DETC2007-35375.

As embedded designs become more widespread and complex they tend to use more modern processors. Such processors will often include features (such as pipelines, caches, and branch predictors) which help to improve performance. While such performance improvements are welcome, they come at the price of predictability. More specifically, the use of advanced processor hardware makes it difficult to predict the worst-case execution time (WCET) of tasks. As part of an effort to address these problems, Puschner and Burns (Proc. 7th IEEE International Workshop on Object-Oriented Real-Time Dependable Systems, Jan. 2002) proposed the “single path programming paradigm”. As its name implies program code written according to this paradigm has only one execution path: this helps to ensure a constant execution time. Yet there are two problems with the techniques described by Puschner and Burns: (i) they are applicable only to hardware which supports “conditional move” or similar instructions; (ii) their balancing approach increases power consumption. In the present paper, we begin to address both of these problems with a set of novel code-balancing techniques. The effectiveness of these new techniques is explored by means of an empirical study.

Commentary by Dr. Valentin Fuster
2007;():73-81. doi:10.1115/DETC2007-35521.

The parametric design of mechatronic systems requires several detailed analyses of the system, thereby slowing down the design process significantly. In the recent past, there has been a lot of interest in using lower fidelity, but higher efficiency metamodels (also called surrogate models) instead of the actual detailed models to guide parametric design, particularly in the early stages of parametric design. One common approach to forming metamodels is to run the detailed model to obtain the system response at selected points in design space and fit a response surface to the results which becomes the metamodel. Since this method uses only zero order information at each design point, a large number of points are required to form a reasonably accurate metamodel. For example, in a single design variable problem, a two-point response surface can only be linear, whereas we can generate a cubic response surface if we also had derivative information at the two points. In this paper, we present a metamodeling approach for mechatronic systems that computes and utilizes first order derivative information at each point in the design space at which a detailed analysis is performed. The first order derivative information that is computed is the set of design sensitivity coefficients of the system state variables and performance functions. A unified modeling approach for the mechanical, electrical, and electronic aspects of the system is first developed. This approach generates a single set of governing equations for the entire system in the form of a system of differential-algebraic equations (DAE’s). Based on these DAE’s, a set of equations in the state design sensitivity coefficients is analytically derived using a direct differentiation approach. This set of equations also turns out to be a set of DAE’s which can be solved simultaneously in parallel with the system governing equations. We have successfully implemented this methodology for design sensitivity analysis of multidisciplinary systems in a computational platform called MIXEDMODELS (Multidisciplinary Integrated eXtensible Engine for Driving Metamodeling, Optimization, and DEsign of Large-scale Systems). Once we know the state design sensitivity coefficients, we can compute the design sensitivity coefficients of any system performance function. After we have obtained the necessary design sensitivity information, we can devise several schemes for generating a metamodel for the system based on the sensitivity information. Some examples of metamodels obtained using this approach are presented for selected mechatronic systems, along with the relevant accuracy measures.

Commentary by Dr. Valentin Fuster
2007;():83-91. doi:10.1115/DETC2007-34558.

Interaction in distributed component based software-architectures can become a rather complex and error prone issue. As it is good practice to keep application concerns separated from infrastructural ones, component based applications typically rely on communication middleware to cope with matters of distribution and heterogeneity. Unfortunately, generic middleware tends to be monolithic, heavyweight software, which is unacceptable in resource constrained embedded systems. Communication middleware for distributed embedded systems has to be custom tailored to the application’s interaction needs and therefore shall be as lightweight as possible. By applying the component paradigm to the communication middleware, a practical methodology can be defined, that allows the middleware’s automatic generation from the application’s architectural models and structural designs of explicit component connectors with a well defined set of prefabricated basic building blocks—so called communication primitives. This paper contributes by specifying the most common structural designs for explicit connectors within the automotive domain and thereby, in addition identifies a set of classes of automotive communication primitives. Thus this paper provides the sound foundation for automatic, model driven middleware synthesis by specifying all necessary basic modules.

Commentary by Dr. Valentin Fuster
2007;():93-101. doi:10.1115/DETC2007-34561.

New design methodologies at higher abstraction levels are necessary to deal with the increasing complexity of modern embedded systems. As a consequence, new design paradigms must supersede traditional design methods to bridge the abstraction gap which often exists between specification and implementation. This paper examines several examples which evaluate the applicability of Esterel, a language with well-defined semantics for specification and verification of reactive control systems. Implementation size, performance and design effort were selected as measures to assess the benefits of this design approach in comparison to a traditional one.

Commentary by Dr. Valentin Fuster
2007;():103-116. doi:10.1115/DETC2007-35758.

Virtual Instruments (VIs) are popularly used for testing, measurement, simulation, and control of instruments and mechatronic systems. A virtual instrument is typically programmed using graphical icons, called a G language. Although using graphical icons is simple and easy, it is quite inefficient for development of applications with special requirements and operations which have not been implemented in advance in a VI. It would be desirable to combine the ease of use of the G language with traditional programming for development of complicated applications in VI. This paper describes the design, implementation and application of embedding a C/C++ interpreter into a VI for scripting blocks in C/C++. With a C/C++ interpreter enabled VI, complicated algorithms and operations can be achieved using a script code associated with a graphical icon called the C script block. The ideas are illustrated by embedding a C/C++ interpreter into a LabVIEW platform through both techniques of code interface node (CIN) and dynamic link library (DLL) available for interfacing external programs in LabVIEW. The application of script blocks in VI is illustrated by the harmonic wavelet analysis for the vibration of a traffic detection system on the highway. Embedding a C/C++ interpreter into VIs has a great potential for enhancing the VIs with easy programmability for handling complicated applications.

Topics: Instrumentation
Commentary by Dr. Valentin Fuster
2007;():117-126. doi:10.1115/DETC2007-34227.

Future space exploration will demand the cultivation of human-robotic systems, however, little attention has been paid to the development of human-robot teams. Current methods for autonomous plan creation are often complex and difficult to use. So a system is needed that enables humans and robotic systems to naturally and effectively collaborate. Effective collaboration takes place when the participants are able to communicate in a natural and effective manner. Grounding, the common understanding between conversational participants, shared spatial referencing and situational awareness, are crucial components of communication and collaboration. This paper briefly reviews the fields of human-robot interaction and Augmented Reality (AR), the overlaying of computer graphics onto the real worldview. The strengths of AR are discussed and how they might be used for more effective human-robot collaboration is described. Then a description of an architecture that we have developed is given that uses AR as a means for real time understanding of the shared spatial scene. This architecture enables grounding and enhances situational awareness, thus laying the necessary groundwork for natural and effective human-robot collaboration.

Topics: Robots , Collaboration
Commentary by Dr. Valentin Fuster
2007;():127-133. doi:10.1115/DETC2007-34997.

Series Elastic Actuators are force actuators with applications in robotics and biomechanics. In linear Series Elastic Actuators, a large force bandwidth requires a stiff sensor (spring), but the output impedance puts an upper limit on this parameter, therefore selecting the proper spring is difficult in these actuators. In this paper, Series Elastic Actuator is modeled with a nonlinear, stiffening spring and controlled using the Gain Scheduling method. Simulations show that both linear and nonlinear models have similar force bandwidths, but the nonlinear one shows much lower output impedance. Hence, the choice of spring for actuator design is an easier task than that of the linear model. Also, as a force-augmenting device for the knee joint in normal human gait, the nonlinear model acts better in simulations.

Commentary by Dr. Valentin Fuster
2007;():135-142. doi:10.1115/DETC2007-35113.

The goal of this project is to develop a teleoperated robotic hand with an emphasis on minimizing cost. Traditionally, use of low-cost sensors meant a sacrifice in the positional accuracy of the finger joints due to noise and high degree of nonlinearity. External vision systems provide accurate data, but suffer from being limited to specific lighting conditions and are hardly mobile. We have developed a robust data glove with a wireless connectivity to a nearby PC that is networked to a robotic arm in the different laboratory through a wireless LAN. In its prototype stage, each finger is modeled as a single joint. To measure the relative angular displacement of each joint, a hollow transparent polyurethane tube is attached along the length of each finger. An Infrared LED and a matched phototransistor are attached at the opposite ends of each tube. The bending of each finger proportionally diminishes the intensity of the light seen by the phototransistor, as a fraction of emitted energy escapes through the bend of the transparent tube. To filter the affects of external lighting and mains coupling each IR source is modulated at different frequencies to prevent interference between the signals. The relationship between relative angular displacement and the sensor signal is a highly nonlinear function that we have linearized through a combination of a non-linear amplifier and a digital look-up-table (LUT). The LUT is generated by custom-designed computer vision software that fits the true angular displacements to the function generated by passing the signal through a non-linear amplifier stage. A low-cost onboard 8-bit microcontroller applies the stored LUT to the digitized measurements from the sensors. The 16-bit positional values are then transmitted by a UDP (Universal Data Protocol) to the client PC that outputs motor commands to the servos in the robotic hand. Positional accuracy, noise and linearity were then analyzed by the same machine vision software and its effectiveness compared to the pure machine vision approach.

Topics: Design , End effectors
Commentary by Dr. Valentin Fuster
2007;():143-151. doi:10.1115/DETC2007-35238.

There are numerous constraints that visually challenged people face in independent mobility and navigation. They primarily use the white cane as a mobility aid allowing them to detect close by obstacles on the ground. The detection of objects above knee height is almost impossible and is a major hindrance for them. In this work, we have reported the design and implementation of a detachable unit which acts to augment the functionality of the existing white cane, to allow knee-above obstacle detection. This unit consists of an ultrasonic ranger and a vibrator controlled by an eight bit microcontroller to offer an increased detection range of three meters. The distance information is conveyed to the user through non-interfering multi-frequency vibratory stimuli, the frequency of vibration indicating the proximity of obstacles. This unit is also capable of detecting fast moving obstacles. Considerable effort has gone into the electromechanical design of this unit conveying the vibrations effectively and ensuring that it is easily attachable on the existing white cane without sighted assistance. A crucial design optimization goal was cost — the unit has been developed as a “low cost” device which is affordable by the poor in developing countries.

Topics: Knee
Commentary by Dr. Valentin Fuster
2007;():153-161. doi:10.1115/DETC2007-35844.

Firefighter’ chief reason for entering a burning structure is to search for and rescue potential victims. Currently, their primary method for communication is an often-congested two-way radio which the firefighters use from within a burning building to relay their activities (and other information) to an external battalion chief. In response to discussions with firefighters in the field, we introduce an approach for automatically segmenting and classifying a select set of activities using wireless accelerometers attached to the human body. The activities we focus on are the ones that are most commonly conducted by firefighters and that are important to the battalion chief for understanding the ongoing search and rescue. In our implementation, sensors continuously measure the acceleration of a small number of body segments and transmit data back to a central base station. At runtime, our system classifies data for short intervals, relying on training examples of the activities of interest. We show that our approach can appropriately detect motions in real-time without significant latency using as few as two accelerometers.

Topics: Sensors , Motion
Commentary by Dr. Valentin Fuster
2007;():163-168. doi:10.1115/DETC2007-34117.

In this paper, a voice command system for autonomous robots is proposed as a project. The methodology adopted is based on hybrid techniques used in speech recognition which are zero crossing and extremes with dynamic time warping followed by a decision system based on independent methods test results. To implement the approach on a real time application, a Personal Computer interface was designed to control the movement of a set of robots by voice commands. The voice command system for four autonomous robots is designed. The main parts of the robots are a microcontroller from Microchip PIC16F876, a set of ultrasonic modules and a radio frequency receiver module.

Commentary by Dr. Valentin Fuster
2007;():169-178. doi:10.1115/DETC2007-34261.

Digital Image-based Elasto-Tomography (DIET) is an emerging technology for non-invasive breast cancer screening. This technology actuates breast tissue and measures the surface motion using digital imaging technology. The internal distribution of stiffness is then reconstructed using Boundary Element or Finite Element Methods (FEM or BEM). However, obtaining accurate imaging at high frequency and high resolution in terms of numbers of pixels is challenging if enough accuracy is to be obtained in the motion sensing to deliver a useful result. The overall focus of such mechatronic and digitally centred systems is on providing a low-cost, radiation dose-free and portable screening system capable of screening numerous patients per day — in direct contrast to current low throughput, non-portable and high cost x-ray and MRI based approaches. Thus, DIET technology relies on obtaining high resolution images of a breasts surface under high frequency actuation, typically in the range of 50–100Hz. Off-the-shelf digital cameras and imaging elements are unable to capture images directly at these speeds. A method is presented for obtaining the required high speed image capture at a resolution of 1280×1024 pixels and actuation frequency of 100Hz. The prototype apparatus presented uses two imaging sensors in combination with frame grabbers and a dSpace™ control system, to produce an automated image capture system. The system integrates a precision controlled strobe lighting system to selectively capture sinusoids at different points in the sinusoidal cycle of response. The final working system produced images that enabled effective 3D motion tracking of the surface of a silicon phantom actuated at 100Hz. The surface of the phantom was strobed at pre-selected phases from 0 to 360 degrees, and an image was captured for each phase. The times at which image capture occurred were calculated for a phase lag increment of 10 degrees resulting in an image effectively every 0.00028s for the actuator cycle of 0.01s. The comparison of the actual trigger times and pre-selected ideal trigger times gave a mean absolute error of 1.4%, thus demonstrating the accuracy of the final system. Final validation is performed using this system to track motion in a silicon gel phantom. The motion is tracked accurately using a novel Euclidean Invariant signature method. Both cameras delivered similar results with over 90% of points tracked to within 1–2%. This level of accuracy confirms the ability to effectively accurately reconstruct the stiffness as validated in other related studies.

Topics: Cancer
Commentary by Dr. Valentin Fuster
2007;():179-189. doi:10.1115/DETC2007-34320.

Swarm robotics is an innovative approach to the control and coordination of multi-agent systems that use naturally inspired swarm intelligent methods to perform tasks. A swarm based approach can decrease the complexity and the cost of designing a cooperative multi-robot system. This paper proposes a general engineering approach to develop a robotic swarm that focuses on how to synthesize an emergent behavior and the associated inputs to this end. We validate our methodology by engineering a swarm to simultaneously rendezvous on a stationary light source. Furthermore, we also considered the case when the light source is slowly moving. The design is simulated in NetLogo, an agent-based modeling software, and implemented on the MASnet robot platform. This work demonstrates the basic knowledge and tools required to engineer a robotic swarm.

Commentary by Dr. Valentin Fuster
2007;():191-202. doi:10.1115/DETC2007-35564.

With limited available space in the city and increasing land cost, multi-storey and high-rise buildings now dominate most urban areas of the world. The irresistible trend to build taller and taller buildings to leverage increasing land cost turns elevator from a tool of convenience to a necessity of life. This dependence of elevator further requires its continuous function in spite of power failure caused by a variety of reasons. Reliable and effective elevator power backup system becomes an urgent need today. In this work, advanced electric power backup technologies, including battery, ultracapacitor and hydrogen fuel cells, are examined. To design a functional elevator backup power system, and to assess the feasibility of a battery–ultracapacitor–fuel cell hybrid elevator backup power system with superior performance, the modeling and simulation of an elevator and its backup power system are carried out. Based on its resemblance to an electric vehicle traveling vertically, the elevator, its power need and performance are modeled using the MatLab/Simulink based hybrid vehicle design and analysis tool, ADvanced VehIcle SimulatOR (ADVISOR). The modeling and simulation provide guidelines for selecting and sizing energy storage and conversion devices. More importantly, the quantitative analysis allows complex battery–ultracapacitor–fuel cell hybrid backup power system to be optimized to reach the best potential of each components for a given elevator usage cycle. To explore the feasibility of wide commercial applications of this technology, the initial cost, maintain costs and reliability of the battery–ultracapacitor–fuel cell hybrid elevator backup power system are also discussed.

Commentary by Dr. Valentin Fuster
2007;():203-208. doi:10.1115/DETC2007-34153.

Automatic generation of robot trajectory for adhesive spray is highly desirable for shoe manufacturing. However, nowadays robotic trajectories are programmed by teach-in instead of automatic approaches. To cope with it, an approach based on a programming tool will be described. It aims at enabling the automatic generation of robot spray trajectories from different kinds of shoe sole models in three-dimensional CAD files. Trajectory could be generated as an offset curve on the surface patch of shoe sole. A set of operating points in spray trajectory can be calculated by means of linear interpolation. At the same time, their orientations including tangential directions and normal directions are computed. Results show that this approach is highly time-efficient by avoiding tedious teaching processes. This study will increase the automation level of the shoe production as well as its flexibility, and is therefore expected to provide higher productivity.

Commentary by Dr. Valentin Fuster
2007;():209-217. doi:10.1115/DETC2007-34576.

In this article an educational embedded mechatronic system based on the MATLAB xPC target is presented. xPC target, a tool provided by MATLAB and its Simulink toolbox, offers a practical means for developing a hardware-in-the-loop (HIL) simulation environment. Since ordinary personal computers (PCs) can be used for modeling, analysis, design, monitoring, and control of the process, the setup becomes suitable for rapid-prototyping, research, and educational use. An application example of a double inverted pendulum on a cart that is digitally controlled is presented and discussed. The system is fully implemented by means of two PCs, MATLAB, Simulink, xPC target, a data acquisition card, an AC servomotor, and three optical encoders. It is shown that, through this technology, high sampling frequencies can be obtained by even using a Pentium III PC. Tele monitoring and control through a network are demonstrated.

Commentary by Dr. Valentin Fuster
2007;():219-225. doi:10.1115/DETC2007-35203.

Open source software have evolved into powerful tools for real-time control of mechatronic systems. They are of interest for academic purposes, as they promise high flexibility at low cost. In this paper, we investigate the performance of an open source control architecture based on the Linux Real-Time Application Interface (RTAI) through two applications, a haptic interface for surgery simulation and a setup for the micromachining of glass. Both applications demand a compact real-time system with sufficient precision (i.e. low jitter) for online process control and data acquisition. The real-time control has been realized on a laptop with a USB-port data acquisition card. Performance measurement results show that high quality real-time control can be performed up to 2kHz via USB communication, which is sufficient for a large range of robotic or mechatronic applications. Drawbacks like the need for considerable knowledge of Linux internals for successful installation as well as the current limitations are discussed and strategies are proposed to overcome these. Both setups are currently being used for ongoing research as well as for educational purposes.

Commentary by Dr. Valentin Fuster
2007;():227-234. doi:10.1115/DETC2007-35427.

Unmanned Aerial Vehicles represent today an advanced and complex robotics platform for novel tasks. For example, UAVs can be used in applications for traffic monitoring and surveillance, emergency services assistance, photogrammetry and surveying. Generally, an UAV must be fully autonomous; autonomy is accomplished by a complex interconnection of systems related to a wide range of topics, e.g., flight low level control, navigation and task-based planning, elaboration of sensor signals, software architecture for reactive behaviours, communication. Today the challenge is the ability to insert UAVs in a cooperative network based on autonomous agents as UAV, UGV (Unmanned Ground Vehicle) to accomplish a specific task a priori defined. In this paper we introduce a prototype of autonomous aerial vehicle, the Helibot helicopter, specifically designed for applications as surveillance and security.

Topics: Surveillance
Commentary by Dr. Valentin Fuster
2007;():235-243. doi:10.1115/DETC2007-35741.

Electronic imaging informatics spans a diverse range of applications. These applications would benefit from an interpretive imaging platform, which allows dynamic manipulation and processing of electronic images. Ch is an embeddable C/C++ interpreter that provides an interpretive platform for C/C++ based scripts and programs. Combining Ch with ImageMagick provides the functionality for rapid development of user defined image manipulation and processing applications and scripts. The presented Ch ImageMagick package provides users with the ability to interpretively execute C code based on the ImageMagick C library. This article describes the integration of ImageMagick and Ch. The use of ImageMagick utilities in Ch scripts for rapid prototyping is illustrated. A Web-based example demonstrates the use of Ch and ImageMagick in C based CGI scripting to facilitate the development of Web-based applications involving image manipulation and processing.

Commentary by Dr. Valentin Fuster
2007;():245-254. doi:10.1115/DETC2007-34263.

Semi-active dampers and actuators hold significant promise for their ability to add supplemental damping and reduce structural response, particularly under earthquake loading. Novel devices utilizing off the shelf components and control systems are used to modify structural response. Devices are presented from design, modeling, analysis and validation via hybrid testing and experimental shake table results. All cases are compared with independent analytical predictions based on first principles analysis.

Commentary by Dr. Valentin Fuster
2007;():255-265. doi:10.1115/DETC2007-34335.

A method for voltage commutation of a three-phase wye-connected sinusoidal brushless permanent magnet motor is presented. The method combines a model-based approach with space-vector modulation to compensate for undesirable effects of winding inductance and to maximize utilization of power source bus voltage. The proposed approach provides improved torque-speed performance and higher efficiency of the motor, which benefits are particularly significant in high-speed and cost-sensitive applications that lack current feedback capabilities. The benefits are demonstrated experimentally on a high-speed linear drive for a precision robotic system.

Commentary by Dr. Valentin Fuster
2007;():267-274. doi:10.1115/DETC2007-34563.

The main control objective of an Antilock Braking System (ABS) is to increase the tractive forces between wheel and road surface by keeping the wheel slip at the peak value of μ – λ curve. Conventionally, it is assumed that optimal wheel slip is constant. In this paper, a grey sliding mode controller is proposed to regulate optimal wheel slip depending on the vehicle forward velocity. ABS exhibits strongly nonlinear and uncertain characteristics. To overcome these difficulties, robust control methods should be employed. The concept of grey system theory, which has a certain prediction capability, offers an alternative approach to conventional control methods. The proposed controller anticipates the upcoming values of wheel slip and optimal wheel slip, and takes the necessary action to keep wheel slip at the desired value. The control algorithm is applied to a quarter vehicle model, and it is verified through simulations indicating fast convergence and good performance of the designed controller.

Commentary by Dr. Valentin Fuster
2007;():275-283. doi:10.1115/DETC2007-34566.

Accurate torque control of a brushless motor requires the motor’s torque characteristics, which can be captured by a periodic function in motor angle. This paper presents a direct adaptive controller for torque control of brushless motors, which estimates the Fourier coefficients of the periodic function based on the measurements of motor phase voltage and angle. It will be analytically shown that the proposed adaptive controller achieves torque tracking regardless of the trajectories of input signals. Moreover, the adaptive controller does not rely on the modeling of the mechanical load, and that makes control implementation simple and modular. Experimental results obtained from the McGill/MIT motor have demonstrated that motor torque converges to the command torque.

Topics: Torque , Motors
Commentary by Dr. Valentin Fuster
2007;():285-290. doi:10.1115/DETC2007-34709.

Relay feedback was applied to measuring mass even under weightless conditions. A measurement object is driven by a force-output actuator. The motion of the object is controlled by a relay feedback system. The used relay element has dead zone and switches force acting on the object in relation to the position of the measurement object. The mass of the object is determined from the time interval measurement of the on-state and off-state periods. An apparatus was developed for experimental study. It uses a voice coil motor as an actuator, and a pair of photo interrupters for detecting the switching positions. The effects of system parameters on measurement accuracy were studied experimentally. Under the tuned conditions, the measurement errors were within 0.2[%]. Measurement on a base moving freely was also carried out.

Commentary by Dr. Valentin Fuster
2007;():291-296. doi:10.1115/DETC2007-35134.

This paper investigates the control system design of magnetic forces using independent motion control of permanent magnets. In the permanent magnet bearing system, the radial motions of the rotor are passively supported by repulsive forces between ring-shape permanent magnets. The experimental results demonstrate that non contact levitation is achieved by independently PD controlled axial motion of permanent magnets driven by voice coil motors (VCM).

Commentary by Dr. Valentin Fuster
2007;():297-304. doi:10.1115/DETC2007-35178.

For better walking performance of humanoid robots, the measure of ZMP is inevitable. The traditional and basic tool for ZMP measurement is to use a force-torque sensor. A 6-axis force-torque sensor can measure all direction’s force data, 3 forces and 3 torques applied to the body. This paper describes mechanically coupled design of a 6-axis force-torque sensor using strain gauges especially for humanoid robots. In mechanically coupled sensors, force data can not be obtained directly from strain signals. Instead output data should be calculated through a additional matrix calculation. Here we suggested a new design method of a small size 6-axis force-torque sensor module for humanoid robots. In this paper, we proposed design guide of the sensor’s structure design, amplitude circuit, and details for the data acquisition board for humanoid robots.

Commentary by Dr. Valentin Fuster
2007;():305-311. doi:10.1115/DETC2007-35508.

A robust controller design is proposed for the active suspension system bench-mark problem. The CRONE control system design used is extended to unstable multivariable plants with lightly damped modes and RHP zeros. Decoupling and stabilizing controller K, is achieved for the open-loop transfer matrix. Fractional order transfer functions are used to define all the components of the diagonal open-loop transfer matrix, β. In defining the fractional open-loop transfer function β0i some elements of the plants, G0 and its inverse must be considered to achieve the stable controller. Optimisation provides the best fractional open-loop βopt . Finally, frequency domain system identification is used to find controller K=G0 −1 βopt .

Commentary by Dr. Valentin Fuster
2007;():313-319. doi:10.1115/DETC2007-35518.

In path tracking design, different methods were developed. In previous works we have presented a method based on fractional differentiation in order to reduce overshoots on the actuator output. It allows the generation of an optimal movement reference-input leading to a minimum path completion time, taking into account the maximum velocity, acceleration and jerk, and the bandwidth of the closed-loop on which the input is applied. Different strategies were developed. In this paper, three methods taking into account the jerk limitation are compared. A comparison with classical input shaper approach is also done. The two first methods, based on fractional differentiation, are used through a Davidson-Cole prefilter with acceleration or jerk bang bang input, to ensure continuity on acceleration and jerk signals on the actuator. The third approach is based on preshaper synthesis with jerk limited input; the shaped input is obtained by convolving desired input with an impulse sequence. The synthesis methodologies of the different methods are studied. Performances are compared on an example, in both frequency and time domains.

Topics: Design
Commentary by Dr. Valentin Fuster
2007;():321-327. doi:10.1115/DETC2007-35200.

Optical sensor offers remarkable advantage compared with traditional sensor, such as electromagnetic immunity, small size, and light weight. A low-cost intensity-based plastic optical fibre (POF) sensor is presented in this paper to measure both static and dynamic strain on a cantilevered beam. The principle of measurement is that the intensity of transmitted light changes as strain changes. By detecting the transmitted light intensity, the change of strain can be measured. First, the principle and design of the sensor are presented. Three POF sensors made using three types of housings (silicon rubber tube, rubber tube and PTFE tube) are evaluated to compare their performance, such as sensitivity, resolution and linearity. A comparison of the strain response of these sensors in static test shows that the soft material (silicon rubber and rubber tube) offers better sensitivity than that of hard material (PTFE tube). However, in dynamic test, PFTE tube gives faster response time compared with rubber tube which is not suitable for high speed test (1k Hz). Both static and dynamic test results have shown that all sensors offer excellent agreement with electrical strain gauge readings and the sensitivity of POF sensor can be up to 20 μ strain. Strain transfer function is also conducted to examine the ability of optical sensors in detection of vibration modes of a cantilevered beam. A PCB piezoelectric accelerometer sensor is attached to the beam as well to measure the acceleration transfer function of the beam, which is used as a reference signal. The results also showed the possibility that POF sensors can be used for structural health monitoring.

Topics: Fibers , Sensors
Commentary by Dr. Valentin Fuster
2007;():329-337. doi:10.1115/DETC2007-35220.

The research work carried out in this paper introduces a robust design method for layout synthesis of MEM resonator subject to inherent geometric uncertainties such as the fabrication error on the sidewall of the structure. The robust design problem is formulated as a multi-objective constrained optimization problem with certain assumptions and treated by a special constrained genetic algorithm. The MEM design used for validation is a crab-leg resonator taken from the literature. The results show that the approach proposed in this research can lead to design results that meet the target performance and are less sensitive to geometric uncertainties than typical designs.

Commentary by Dr. Valentin Fuster
2007;():339-345. doi:10.1115/DETC2007-35264.

The paper describes a whole-field imaging sensor developed on the principles of photoelasticity. The sensor produces colored fringe patterns when load is applied on the contacting surface. These fringes can be analyzed using conventional photoelastic techniques, however, as the loading in the present case is not conventional some new strategies need to be devised to analyze the load imprint. The loading is unconventional in the sense that low modulus photoelastic material is deformed under vertical load in the direction of light travel to induce the photoelastic effect. The paper discusses the efficacy of both RGB calibration and phase shifting techniques in sensing applications. The characteristics of fringe patterns obtained under vertical and shear loads have been studied and the results obtained under these conditions are discussed with their limitations specifically when this is applied for sensing applications. Finally a case study has been conducted to analyze a foot image and conclusions drawn from this have been presented.

Topics: Sensors , Imaging
Commentary by Dr. Valentin Fuster
2007;():347-352. doi:10.1115/DETC2007-35266.

Linear micro motors lend themselves to being fabricated in a hybrid fashion, i.e. fabricating stator and traveler on separate wafers. While such an approach provides substantial flexibility in fabricating the micro components, it requires to coming up with an appropriate guide system, as well as an assembly process for system integration. This process has to assure that the most critical dimension (typically the air gap between stator and traveler) is achieved. In general, such a challenge is best met by a self-alignment assembly process. The first generation of linear actuators used an assembly process where a ball guide consisting of ground V-grooves and 200 μm ruby balls was created. Both micro step motors and micro synchronous motors were equipped with such guides, which proved to be quite reliable. However, to further minimize friction, future linear micro motors will feature magnetic levitation bearings. This paper presents an assembly process for such micro motors.

Commentary by Dr. Valentin Fuster
2007;():353-359. doi:10.1115/DETC2007-35481.

In the modern aeronautics and aerospace industry, there is a manifold amount of applications emerging for wireless sensors. While many new systems are making use of radio transmitters, EADS Innovation Works has developed a concept for transmitting energy and data to the inside of hermetically sealed envelopes used for hydraulic accumulators, fuel tanks, oxygen bottles, etc. For such kind of metal enclosures, the use of radio frequency is impossible as the electromagnetic waves are blocked by the surrounding material. Classical approaches like using wire-based feed-throughs threaten the reliability of the overall system and hence, they are less attractive especially when safety relevant components are targeted. The system described in this paper makes use of ultrasonic transmission techniques in order to power and communicate with a wireless sensor inside a metal enclosure. An innovative platform and communication concept allows to efficiently read data from basically any type of low power commercial sensors of the shelf. Major design drivers for the overall system are a high level of integration and high reliability.

Commentary by Dr. Valentin Fuster
2007;():361-366. doi:10.1115/DETC2007-35829.

Conventional condition monitoring of electrical machinery is conducted by measuring signals such as currents and vibrations outside the motor. Wireless sensors now provide a means of accessing and measuring useful signals inside the motor where the phenomena responsible for failure occur. These sensors are capable of not merely sensing, but also processing, storage and eventually communication. Since all these activities require power that is supplied conventionally by batteries, the useful life of the sensor node is limited by the life of the battery. This paper describes the design of an energy scavenger capable of collecting energy from the fringing field in a three-phase induction motor. The field in the magnetic filed is converted to electrical energy for use in intelligent wireless sensor nodes. The alternating magnetic field in a three phase induction motor is first measured by the hall-effect sensors. A coil wound on a ferrite core harvests the leaked energy. The experimental results are compared to the theoretical calculations of induced voltage. The paper describes results from tests conducted with a prototype coil that is used to power wireless sensor nodes in a motor running at full speed.

Commentary by Dr. Valentin Fuster

19th Reliability, Stress Analysis, and Failure Prevention Conference (RSAFP)

2007;():369-373. doi:10.1115/DETC2007-34417.

A probabilistic analysis method is developed for static response of the turbine blade with parametric uncertainty. The material, geometric parameters and loadings of blade exhibit notable random fluctuations, so the conventional deterministic analysis of blade can’t provide complete information. The Stochastic analysis can tackle the uncertainties in blade parameters and obtain the probabilistic characteristics of the response. In this paper, the study focuses on the 3D stochastic finite element method (3DSFEM) of the static response for turbine blade. The perturbation stochastic finite element method (PSFEM) is used to calculate probabilistic characteristics of the static response of the turbine blade. The random response of a turbine blade subjected to the steam pressure and the centrifugal force is analyzed using perturbation stochastic finite element method. The example shows that the present method is valid.

Commentary by Dr. Valentin Fuster
2007;():375-382. doi:10.1115/DETC2007-34455.

Stress distributions in adhesive-rivets combination joints under tensile shear loadings are analyzed using a three-dimensional finite element method. The effects of the adherend thickness, the number of rivets and the rivet locations on the stress distributions at the interfaces are examined. Experiments to measure the rupture loads of the joints were carried out. As the results, it was found that the peel stress near the edges of the interfaces decreased as the adherend thickness increased. The maximum value of the maximum principal stresses near the edges of the interfaces decreased as the interval between the two rivets in the longitudinal direction decreased in the case where two rivets were combined. However, small effect of the interval between the two rivets in the lateral direction was found in the case of two rivets. The maximum value of the maximum principal stresses near the edges of the interfaces decreased as the interval between the four rivets in the longitudinal direction decreased and that in the lateral direction increased in the case where four rivets were combined. Discussion on the rupture loads of adhesive-rivets combination joints was made. The rupture loads of the joints increased as the number of rivets increased. The rupture loads of the adhesive-rivets combination joints could be increased more than those of only-riveted joints in the case of two rivets. The rupture loads of adhesive-rivets combination joints were found to be almost the same as those of only-riveted joints in the case of four rivets.

Commentary by Dr. Valentin Fuster
2007;():383-388. doi:10.1115/DETC2007-34613.

In this paper the 3D model of the three stage helical gearbox was establish using UNIGEAPHICS (UG) firstly, and then the structure static analysis was realized by ANSYS. Accordingly the gear-box’ stress distribution, deformation can be obtained, so the strength and stiffness of the gear-box can be calculated based on the stress and the deformation results, which helps us to evaluate whether the design demand can be satisfied or not. The structure static analysis provides suggestions for the improvement of model design, and the finite element simulation to the large, heavy-duty gear-box reducer can provide technical assurance for the dependability of the production.

Commentary by Dr. Valentin Fuster
2007;():389-398. doi:10.1115/DETC2007-34736.

Propagation of a critical unstable crack under the action of static or varying stresses is determined by the intensity of strain field at tips of the crack. Stress intensity factor (SIF) is an important parameter in fracture mechanics, which is used as a criterion to judge the unstable propagation of a crack and plays an important role in calculating crack propagation life. SIF is related to both geometrical form and loading condition of a structure. In the paper, a weight function method is introduced to study crack propagation of center through cracks and edge cracks in a finite-size plate. In addition, finite element method, linear regression, and polynomial interpolating technique are used to simulate and verify the proposed method. Comparison studies among the proposed and current methods are performed as well. The results show that the weight function method can be used to calculate SIF easily.

Topics: Weight (Mass) , Stress
Commentary by Dr. Valentin Fuster
2007;():399-405. doi:10.1115/DETC2007-35563.

The fractal-like finite element method (FFEM) has been proved to be an accurate and efficient method to analyse the stress singularity of crack tips. The FFEM is a semi-analytical method. It divides the cracked body into singular and regular regions. Conventional finite elements are used to model both near field and far field regions. However, a very fine mesh of conventional finite elements is used within the singular regions. This mesh is generated layer by layer in a self-similar fractal process. The corresponding large number of degrees of freedom in the singular region is reduced extremely to a small set of global variables, called generalised co-ordinates, after performing a global transformation. The global transformation is performed using global interpolation functions. The Concept of these functions is similar to that of local interpolation functions (i.e. element shape functions.) The stress intensity factors are directly related to the generalised co-ordinates, and therefore no post-processing is necessary to extract them. In this paper, we apply this method to analyse the singularity problems of sharp notched plates. Following the work of Williams, the exact stress and displacement fields of a plate with a notch of general angle are derived for plane stress and plane strain conditions. These exact solutions which are eigenfunction expansion series are used as the global interpolation functions to perform the global transformation of the large number of local variables in the singular region around the notch tip to a few set of global co-ordinates and in the determination of the stress intensity factors. The numerical examples demonstrate the accuracy and efficiency of the FFEM for sharp notched problems.

Commentary by Dr. Valentin Fuster
2007;():407-414. doi:10.1115/DETC2007-34181.

Composite parts have been used widely for lightening and strengthening mechanical parts, and it is necessary to know the contact stress distributions at the interfaces of the composites. In this paper, the interface stress distribution in composite cylinders of epoxy and steel under push-off loadings is analyzed using axisymmetrical theory of elasticity as a three-body contact problem. Analogous test was conducted to determine the relationship between the normal stress and the shear stress. Using two stress singularity parameters obtained from the numerical stress analyses and analogous test results, a method for estimating the strength of the composite cylinders was proposed. In the numerical calculations, the effects of the diameter and Young’s modulus of the solid cylinders on the interface stress distributions are clarified. It is seen that the normal stress and the sheer stress at the lower edges of the interface increase as Young’s modulus of the solid cylinders increases. It is also found seen that the normal stress increases and the sheer stress decreases as the diameter of the solid cylinders increases. The experiments were carried out for measuring the ruptured push-off loadings of the composite cylinders. In the experiments, the effects of the diameter of steel cylinders were examined. It is seen that the push-off strength increases as the diameter of the steel cylinders increases. The numerical results are in fairly good agreements with the experimental results.

Commentary by Dr. Valentin Fuster
2007;():415-422. doi:10.1115/DETC2007-34403.

Electrospun polyacrylonitrile (PAN) fiber precursor based Carbon Nanofiber (CNF) mats were produced and impregnated with epoxy resin. The mechanical properties of as-prepared nanofibers in the mat and short fiber filled epoxy nanocomposite forms were determined to demonstrate the effect of fiber aspect ratio and interconnecting network on those properties. Our experimental results reveal that epoxy nanocomposites containing Electrospun Carbon Nano Fibers (ECNF) with high fiber aspect ratio and high interconnecting network in the non-woven mat form yield better mechanical properties than those filled with short ECNFs. The ECNF mat in epoxy nanocomposites provides better homogeneity, more interlocking network, and easier preparation than short ECNFs. Mechanical properties of ECNF mat-epoxy nanocomposites, which we obtained using tensile and flexural tests, such as stiffness and modulus increased, while toughness and flexural strength decreased, compared to the neat epoxy resin. Dynamic Mechanical Analysis (DMA) results showed, higher modulus for ECNF mat-epoxy nanocomposites, compared to those for neat epoxy resin and short ECNF-epoxy nanocomposites. The epoxy nanocomposites had high modulus, even though the glass transition temperature, Tg values dropped at some extents of ECNF mat contents when compared with the neat epoxy resin. The cure reaction was retarded since the amount of epoxy and hardener decreased at high ECNF contents together with the hindering effect of the ECNF mat to the diffusion of epoxy resin and curing agent, leading to low crosslinking efficiency.

Commentary by Dr. Valentin Fuster
2007;():423-427. doi:10.1115/DETC2007-34406.

Polystyrene (PS)-Organically modified montmorillonite (OMMT) nanocomposites processed by injection molding were investigated for the effects of different OMMT concentration and melt-blending conditions using a KrF excimer laser operating at 248 nm wavelength. Results indicate that PS-OMMT nanocomposites show improved resistance to excimer laser irradiation, as revealed by reduced mass loss due to laser ablation at their surfaces, when the OMMT concentration is below 2 wt%. Further increases in OMMT wt%, above the 2 wt% value, resulted in increased mass loss due to laser ablation, when compared with ablation of the neat PS material. Our experimental results also revealed that the dispersion (exfoliation) state of OMMT plays an important role in excimer laser ablation behavior of PS-OMMT nanocomposites. This result indicates the possibility for using the excimer laser as an evaluation tool in assessing the degree of exfoliation in clay reinforced polymer nanocomposites, including the assessment of spatial distribution of clay particles in injection molded nanocomposite articles, as illustrated in this work.

Commentary by Dr. Valentin Fuster
2007;():429-433. doi:10.1115/DETC2007-35650.

We report easy and fast fabrication methods to prepare densely packed polystyrene (PS) and silicon nano-dots using one-step excimer laser irradiation on cylindrically nanopatterned block copolymer materials, without any additional selective etching steps before a non-selective etching. Preferential etching in more ultraviolet (UV)-sensitive block component, and non-selective removal of all block components allowed transferring nanopatterns in block copolymer masks to inorganic silicon substrates, when an appropriate laser intensity was used. Surface melt flows of block components, which severely undermine the initial orders of nanopatterns in a block copolymer mask, were observed at the laser intensity near the ablation threshold of the less UV-sensitive component. Thus, in order to obtain mask-image-like topographic nanopatterns on the target material surfaces, the intensity of excimer laser radiation should be sufficiently lower than the ablation threshold of the less UV-sensitive component as long as the intensity is higher than that of the more UV-sensitive component. Numerical analyses on the photothermal excimer laser ablation in binary mixture systems predicted the presence of a matrix-assisted excimer laser ablation in the less UV-sensitive component at the laser intensity lower than its ablation threshold, owing to the heat conduction from the more UV-sensitive component during the nanoscopic level of time duration.

Commentary by Dr. Valentin Fuster
2007;():435-444. doi:10.1115/DETC2007-35699.

Exposure to high noise levels may be the most common occupational hazard. Recent estimates suggest that as many as 30 million Americans are exposed to noise levels greater than the current safe limits for workplaces. At current durations of exposure, it is expected that 25% of these workers will develop permanent, noise-induced hearing loss. In many of these industrial environments, high levels of vibration also exist that can lead to several injuries and ailments. To address the adverse effects associated with the use of high noise emission impact tools, a study was initiated to develop and evaluate alternate tool designs that reduce the potential for hearing loss and vibration-related injuries. Recent work has focused on integrating advanced engineering polymers (composites) into tool designs for the purpose of eliminating direct metal-to-metal impact. This approach has several significant performance advantages including reduced operator discomfort due to hand-arm mechanical shock, reduced noise, and less danger from flying metal fragments. To quantify sound emission characteristics of these new designs, continuous sound pressure, maximum sound pressure, and maximum sound pressure level were measured using an array of five precision microphones each located 1 meter from the tool. Data was sampled at 40 kHz while test subjects operate both pneumatic tools and hand-struck tools. Frequency spectra of the sound pressure signals were examined for all tool treatments, and indicate that the addition of a polymer insert between metal impact components significantly reduces noise emission, especially at higher frequencies. Similar reductions were observed in vibration transmission in the hand and arm. As a result, tools that integrate polymer-based components may be operated for longer daily exposure times without inducing hearing loss or vibration-related injuries. Data from this study may also help auditory and ergonomic specialists in understanding impulse noise characteristics and exposure.

Commentary by Dr. Valentin Fuster
2007;():445-449. doi:10.1115/DETC2007-34617.

The Weibull distribution is widely used in life testing and reliability studies. Weibull analysis is the process of discovering the trends in product or system failure data, and using them to predict future failures in similar situations. Support Vector Regression is a machine learning method based on statistical learning theory, which has been applied successfully to solve forecasting problems in many fields. In this paper, support vector regression is used to build a parameter estimating model for Weibull distribution. Numerical examples are presented to show good performance of this method.

Commentary by Dr. Valentin Fuster
2007;():451-456. doi:10.1115/DETC2007-34733.

Evaluating reliability and finding the critical components of a diesel engine system is a very important process in quality improvement and new product design. In this paper, a series of reliability indexes were applied in diesel engine reliability evaluation based on maintenance records. Several methods including life cycle distribution and FMEA (Failure Mode and Effects Analysis) were also presented. At the end, a diesel engine (Model 6108ZQ) was used as a case study.

Commentary by Dr. Valentin Fuster
2007;():457-469. doi:10.1115/DETC2007-34849.

Probabilistic failure analysis is essential when analysis of stress-life (S-N ) curves is inconclusive in determining the relative ranking of two or more materials. In 1964, L. Johnson published a methodology for establishing the confidence that two populations of data are different. Simplified algebraic equations for confidence numbers were derived based on the original work of L. Johnson. Using the ratios of mean life, the resultant values of confidence numbers deviated less than one percent from those of Johnson. It is possible to rank the fatigue lives of different materials with a reasonable degree of statistical certainty based on combined confidence numbers. These equations were applied to rotating beam fatigue tests that were conducted on three aluminum alloys at three stress levels each. These alloys were AL 2024, AL 6061, and AL 7075. The results were analyzed and compared using ASTM Standard E739-91 and the Johnson-Weibull analysis. The ASTM method did not statistically distinguish between AL 6010 and AL 7075. Based on the Johnson-Weibull analysis confidence numbers greater than 99 percent, AL 2024 was found to have the longest fatigue life, followed by AL 7075, and then AL 6061. The ASTM Standard and the Johnson-Weibull analysis result in the same stress-life exponent p for each of the three aluminum alloys at the median or L 50 lives.

Topics: Fatigue
Commentary by Dr. Valentin Fuster
2007;():471-482. doi:10.1115/DETC2007-35581.

The design process can be viewed as a series of actions for reducing uncertainty in product or system design specifications. At the beginning of the design process, uncertainty is high because the design space has yet to be explored and decisions have not been made. This uncertainty contributes to design risk, risk due to the engineer’s lack of knowledge and/or information. In design teams, design risk takes on the added dimension of lack of group awareness about the state of knowledge of each team member. To better understand and capture uncertainty inherent in early design, we have developed a methodology to model design evolution in concurrent design teams. The representation is a directed graph that represents the state of a design over time. In this paper we describe our modeling methodology and present a case study of two different design teams. We present the results of modeling a part of the design process. Then we show how the model can be analyzed to understand how information and knowledge transfer was used to make decisions and reduce uncertainty and design risk.

Commentary by Dr. Valentin Fuster
2007;():483-495. doi:10.1115/DETC2007-35706.

This paper introduces a new methodology for probabilistic optimal design of multibody systems. Specifically, the effects of dimensional uncertainties on the behavior of a system are considered. The proposed reliability-based optimization method addresses difficulties such as high computational effort and non-smoothness of the system’s responses, for example, as a result of contact events. The approach is based on decomposition of the design space into regions, corresponding to either acceptable or non-acceptable system performance. The boundaries of these regions are defined using Support Vector Machines (SVMs), which are explicit in terms of the design parameters. A SVM can be trained based on a limited number of samples, obtained from a design of experiments, and allows a very efficient estimation of probability of failure, even when Monte Carlo Simulation (MCS) is used. A modularly structured tolerance analysis scheme for automatic estimation of system production cost and probability of system failure is presented. In this scheme, detection of failure is based on multibody system simulation, yielding high computational demand. A SVM-based replication of the failure detection process is derived, which ultimately allows for automatic optimization of tolerance assignments. A simple multibody system, whose performance usually shows high tolerance sensitivity, is chosen as an exemplary system for illustration of the proposed approach. The system is optimally designed for minimum manufacturing cost while satisfying a target performance level with a given probability.

Commentary by Dr. Valentin Fuster
2007;():497-503. doi:10.1115/DETC2007-34151.

Failure characterization of fracture toughness of a plate containing a single through-the-thickness edge crack and subjected to a tensile stress is investigated. The relationship between the varying ratio of crack length to plate width and the stress intensity factor is examined and compared for elastic, elastic-plastic and nonlinear conditions. Using a numerical illustration, it was found that an increasing ratio increases the stress intensity factor and a decreasing ratio decreases the stress intensity factor regardless of the condition. Hence, the ratio of crack length to plate width can be used as a design parameter that affects the fracture toughness and as a tool of predicting condition for failure.

Commentary by Dr. Valentin Fuster
2007;():505-512. doi:10.1115/DETC2007-34401.

Epoxy/Ni adhesives can be used as integrated circuit (IC) packaging materials due to their lower cost than epoxy/Ag adhesives with acceptable electrical conductivity. In this study, stable and unstable capillary flows of highly filled epoxy/Ni suspensions were investigated with and without cure at room temperature, via the capillary rheometer and syringe extrusion. Variations of the bulk electrical conductivity in these processes were discussed as well. Axial filtration of the polymer binder occurs under the static pressure for Epon815C/Ni/DETA adhesive with 50 wt% of Ni in syringe, resulting in an unstable flow and a cross-sectional filler concentration or electrical conductivity gradient. In dynamic capillary extrusion, lower resin viscosity and apparent shear rates enhance the flow instability and filtering of polymeric binder for epoxy/Ni suspensions with 75 wt% of Ni, thus facilitating a change in bulk electrical conductivity during processing. With increasing shear rates, the force oscillation frequency and force magnitudes increase. Incorporation of Ni nanopowders promotes a stable flow, yet the occurrence of agglomerates somewhat nullifies this advantage. Additionally, different rheological behaviors result as cure proceeds with different resins. Also, occurrence of the agglomerates leads to flow instabilities during processing with cure.

Commentary by Dr. Valentin Fuster
2007;():513-517. doi:10.1115/DETC2007-34610.

Gears are widely used in many practical engineering to transmit torque. In the process of meshing, contact stress will be produced which causes pitting. Shock becomes more and more serious with the increase of pitting and the probability of failure of meshing gears increases. Contact stress analysis is necessary and important to increase the reliability of gear transmission. In this paper, a fuzzy Hertz approximate optimization method and finite element method are used to deal with a practical engineering problem.

Commentary by Dr. Valentin Fuster
2007;():519-523. doi:10.1115/DETC2007-34929.

Damage detection of machinery is always a research field that attracts attentions of many people. In this paper, a novel technique for gearbox damage detection is investigated, which is a wavelet-based singularity analysis method. Wavelet transform is applied to vibration signal, modulus maxima lines are extracted, and conclusions are made based on these lines. Simulated and real vibration data have been analyzed using this approach. The results are presented to show the effectiveness of the method.

Commentary by Dr. Valentin Fuster
2007;():525-530. doi:10.1115/DETC2007-34966.

This paper presents use of conventional photoelastic techniques under unconventional loading situations to evaluate their efficacy in sensing applications. The loading is unconventional in the sense that low modulus photoelastic material is deformed under vertical load in the direction of light travel to induce the photoelastic effect. This is atypical of conventional methods where loading is across the light travel. Both RGB calibration and phase shifting techniques have been used to study the characteristics of fringe patterns obtained under vertical and shear loads. The results obtained under these conditions are discussed with their limitations specially when this is applied for sensing applications. Finally a case study has been conducted to analyze the foot image and conclusions drawn from this have been presented.

Commentary by Dr. Valentin Fuster

4th Symposium on International Design and Design Education

2007;():533-538. doi:10.1115/DETC2007-34289.

Tablet PCs look much like regular laptop computers, except their digitized screens can be swiveled around, folded over, and written on with a stylus. Instructors have recognized that this simple write-on feature gives them the opportunity to change the way in which they lecture in a classroom. This paper examines the application of tablet PCs outside of the lecture hall. Specifically, it describes the application of tablet computers to a final year capstone design course. Particular applications include the replacement of the traditional individual design notebook with a shared electronic notebook and enhancement of sketching as a communication tool. A description of the capstone course is given to provide a context for how the tablets were used. The impact of the tablet PCs is discussed and the results of a user survey are presented.

Commentary by Dr. Valentin Fuster
2007;():539-555. doi:10.1115/DETC2007-34424.

This paper studies “creativity” in engineering education, by examining the perception of instructors and students. We aims to identify factors that impede a creative environment (creativity blockers). The study entails review of established research in the fields of psychology and educational psychology to identify factors which create an educational environment conducive to creativity. These factors are formalized in the Ten Maxims of Creativity in Education, a set of criteria that constitute an educational environment conducive to fostering creativity in students. These maxims form the basis for our work in examining the contemporary engineering education. Extensive surveys are designed, created, distributed and statistically quantified to study the perceptions of engineering educators and students, in comparison to non-engineering educators and students. The results unfortunately show that the current engineering student experiences almost none of the Ten Maxims of Creativity as a part of their academic experience.

Commentary by Dr. Valentin Fuster
2007;():557-566. doi:10.1115/DETC2007-35392.

This study analyzed the effect of team activities to promote team creativity and explored team interaction from the perspective of personal creativity modes. Freshman engineering students participated in the experiment. Teams in experimental group had an exercise of team activity immediately following self-awareness activity for their creativity mode. After team activity, team performances in conceptual design task were evaluated using Creative Product Semantic Scale (CPSS) composed of novelty and resolution categories. The results indicated that team performances of experimental group were significantly higher in CPSS evaluation, specifically in resolution, than those of control group. Also, team interaction of a diverse team and a uniform team from experimental group were analyzed using Interaction Process Analysis. The team interaction analysis showed that team members in diverse team represented very different team interaction patterns among team members, while team members in uniformed team demonstrated very similar patterns. These findings confirm that self-awareness of personal creativity mode help to enhance team creativity and that team interaction reflects some patterns according to personal characteristics.

Commentary by Dr. Valentin Fuster
2007;():567-574. doi:10.1115/DETC2007-35525.

This paper investigates how the infusion of a parametric object-based Building Information Modeling (BIM) methodology has influenced the design responses of engineering students in architectural design studios. BIM provides students with an opportunity to explore the consequences of design alternatives through three-dimensional representation in addition to two-dimensional abstraction during the schematic design phase. The authors qualitatively evaluate data in the participant observation tradition garnered from two architectural design studios in an architectural engineering program. The purpose is to explore how students respond when offered opportunities to visualize energy performance in concert with architectural design. The results indicate that BIM provides more time for realizing the design idea, thereby inducing a higher level of intellectual behavior where the students visually evaluate multiple conditions of design iterations in a qualitative manner while bringing to life the numerical application and analysis procedures of quantitative theory. The engineering students make relatively sophisticated choices regarding building orientation, passive solar heating, daylighting, and envelope design and materials selection.

Topics: Design
Commentary by Dr. Valentin Fuster
2007;():575-580. doi:10.1115/DETC2007-34609.

Laboratory work is an important element in engineering training, which should correspond to up-to-date tendencies in computer-based technologies in design, production, maintenance and preserving mechanisms. Computer-based laboratory work consists of 16 assignments. Seven assignments are carried out on laboratory stands, the remainder are provided on PC, using programs like “Visual Structure Editor”, “DYNAMO”, “APM Win Machine”. The system Visual Structure Editor (VSE) is designed by specialists of “Machine Mechanics and Computer-Aided Design” department, of the Maritime State University named after adm.G.I.NEVELSKOY, Vladivostok, under the direction of prof. Valentina V. Kuzlyakina. The system APM (Automated Projecting of Mechanism) is designed by the research-and-production centre “APM” under the direction of prof.V.Shelofast, from the city of Korolyov, Moscow area. These systems are multifunctional. They allow project different mechanical systems at the stage of structural and parametrical synthesis, carry out strength calculations and design elements of machines and mechanisms. They are good in operation. Teachers and students easily master the systems. Laboratory works with computer support allow students to pass from a concrete object to modeling on a PC, and to solve complex engineering tasks during the education process.

Commentary by Dr. Valentin Fuster
2007;():581-586. doi:10.1115/DETC2007-34612.

The procedure of lever mechanisms structuring being the basis of the majority of mechanical systems is complicated and labor-consuming. The generalized structural modules allow to automate and repeatedly to speed up process of lever mechanisms schemes creation and research of their kinematics in the specialized system “Visual Structure Editor (VSE)”. Ten types of generalized structural modules are offered, which allow to create schemes and to investigate kinematics of lever mechanisms of the second class of any degree of complexity. In this work structuring of various flat mechanisms schemes with any possible number of members based on only 5 types of generalized structural groups is presented. These are a rotating initial link, an onward moving link, a two-driver group with three rotary kinematics couples and two-driver groups with two rotary and one external forward kinematics couples of two types. VSE is broadly used in education process when performing the course designing on engineering discipline.

Commentary by Dr. Valentin Fuster
2007;():587-595. doi:10.1115/DETC2007-35584.

We have designed an intensive, three-week robotics program for high school students that combines theory with hands-on practical experience in cutting edge technologies. Conventional approaches to engineering education are bottom-up. Students are first taught the basics and are then courses that build on the basics. Most students do not take coursework on engineering applications, particularly design and systems engineering, until the end of the curriculum. This has the disadvantage of not exposing students to the excitement in engineering until late in the curriculum. Our goal is to develop a top-down curriculum in which students are introduced first to the applications and systems concepts which then leads to the teaching of fundamentals. This approach has the potential to recruit and retain students in engineering while making the curriculum more relevant and rigorous.

Topics: Robotics , Students
Commentary by Dr. Valentin Fuster
2007;():597-604. doi:10.1115/DETC2007-35902.

Mechanical designs in industry typically do not include adequate specification of allowable part geometry variation. Poorly applied Geometric Dimensioning and Tolerancing (GD&T), ambiguous plus/minus location or orientation controls, and sometimes no variation specifications (only a 3D CAD body) are commonly all that is done. Since improper specifications cause confusion, and since functional requirements are likely either more precise, or less precise, than the manufacturing process will deliver, excessive costs of dealing with geometry variation result. Specifications which unambiguously capture the functional needs of critical part features, combined with properly gathered and consistently reported measurement data would provide a competitive advantage for any company producing a precise mechanical product. The need to capture functional requirements, and also the improved part designs that result when thinking includes the cost & quality issues clarified by GD&T makes this subject an important element of design focused mechanical engineering education. Especially when tolerance analysis and measurement process quality considerations are included, there is sufficient academic rigor to justify additional coursework. The critical seed needed to remedy industry’s knowledge gap regarding dimensional specifications and associated data is to include two academic quarters of GD&T and Dimensional Management design electives as part of every mechanical engineering curriculum.

Commentary by Dr. Valentin Fuster
2007;():605-608. doi:10.1115/DETC2007-34009.

College students in engineering and physical sciences are often educated in “scientific” methods of experimentation. For many years there have been advocates of statistical tools for research and development in design as well as prototyping and testing, yet their acceptance into engineering and technical curricula has been limited. The discussions in this paper explain the rationale for the use of statistical methods such as statistical design of experiments for superior product and process performance. Both educators and students in technical fields would realize that data-driven tools are indeed useful and important for designed-in quality and reliability. In fact, savings and opportunities for enhanced performance via virtually cost free techniques could often be discovered as well. The approach taken, largely based on statistical design of experiments, could be perceived to go against ingrained concepts of “scientific methods” but the efficacy of new product and process design can be readily explained and demonstrated. Such an understanding would be extremely useful in formulating effective design curricula at both graduate and undergraduate levels.

Topics: Design
Commentary by Dr. Valentin Fuster
2007;():609-615. doi:10.1115/DETC2007-34383.

Since 2001 an ‘integral approach’ to building design has been propagated within Dutch building design practice, through continuously developing ‘learning by doing’ workshops. The organization of workshops started during ‘Integral Design’ project in 2000 that was conducted by the Dutch Society for Building Services (TVVL), the Royal Institute of Dutch Architects (BNA) and Delft University of Technology (TUD). The main focus of the project, which ended in 2003, was to raise the awareness of different disciplines about each others positions and problems in relation to building design, and to give an overview of issues influencing design integration and possible solution directions. The used workshops create a setting where the knowledge can be generated and regenerated in relationship to the knowledge development-triangle, in a realistic setting; the Reflexive Practice. In this paper we will explain the results of workshops, give an overview of participants’ assessments (more than 180 professionals took part in TVVL-BNA-TUD workshops) and reflect on preliminary results / conclusions.

Commentary by Dr. Valentin Fuster
2007;():617-624. doi:10.1115/DETC2007-35177.

The most effective method in design and manufacturing education is to experience the series of processes, which are to be given a design subject, the design of the machine to qualify the specification, to manufacture or buy necessary parts, the assembly and the evaluation of performance, by oneself or few people. Firstly, the items to learn and improve in the course for the attending student were listed up and examined. These become the evaluation items of the program by the attending student. The program called ‘Clock Project’ was developed. The subject is to design the clock that displays ‘hour’ and ‘minute’. Various restrictions are installed in the size of machine, the parts can be used and etc. The evaluation function to decide the excellent/poor design is the number of parts. The design with small number of parts becomes an excellent one. A couple of students struggle with the program with collaboration. 3-D CAD is used to design and the efficiency is improved comparing with ordinary hand drafting. Moreover, the digital engineering such as a RP (Rapid Prototype) equipment and EC (Electric Commerce) service for the order of parts are utilized fully. As the result, the management cost was reduced drastically. The participated team designed unique clocks. There was no same clock though many types clock were designed in the class. The creativity is inspired through this program. In the paper, the progressed points are explained comparing with the ordinary educational program. And it is examined that whether the expected effect is obtained or not based on the result of evaluation by the students.

Commentary by Dr. Valentin Fuster
2007;():625-631. doi:10.1115/DETC2007-35836.

The globalization of the marketplace is rapidly transforming business organizations, the nature of the products they sell, product design teams, and the skills and knowledge required to operate effectively in this environment. These changes include global distribution of talent within international organizations, an increasing reliance on virtual collaboration in design teams, greater need to make usable products, and the rise of new markets in emerging economies which have very different needs from tradition markets. This paper discusses the additional knowledge and skills engineers will need to succeed in global organizations, how these skills may be introduced into curricula, and challenges in making these changes. While change is difficult, educational organizations that can do so rapidly will become leaders in future engineering education.

Commentary by Dr. Valentin Fuster
2007;():633-641. doi:10.1115/DETC2007-34380.

Sustainable building will be the major guiding principle for renewal of building and spatial planning practice. Kropman being one of the major Dutch building services contractors is aware of this trend. It is because of this rowing awareness of sustainability that the company puts effort towards knowledge transfer and research with the Dutch knowledge and research institutes. The principles of sustainable building within the IFD (Industrial Flexible Dismountable) concept are applied in the planning of a new building for the Kropman Utrecht department. Aim was an integrated approach within the design process to reach a maximum level of integration between building elements and climate conditioning elements. A newly developed methodology for structuring and documenting integral design processes enables verification and reproduction of decisions made during designing. Its conscious use by professionals results in iteration cycles within and between their own domains. The gradual emergence of a design language that helps structuring design tasks and solutions further stimulates the multidisciplinary exchange of ideas and concepts. This approach of structuring tasks and solutions is tested within a professional context of a building design project. Investigated is if the approach improves and supports the building design process. Besides its added value for building design process, the integral design methodology directly stimulates application of sustainable energy in the built environment.

Commentary by Dr. Valentin Fuster
2007;():643-651. doi:10.1115/DETC2007-34456.

This paper reports on a longitudinal study of lessons learned from a graduate-level New Product Development course taught at the University of California at Berkeley, comparing lessons learned by students during the course with alumni perceptions one to ten years after graduation. Previous research on student learning outcomes in New Product Development (NPD) found that on the last day of class students identify working in multifunctional teams and understanding user needs as their most important lessons learned. This study raises the question of whether or not students maintain the same emphasis on learning outcomes once they have moved on to careers in industry. To answer this question, we conducted 21 in-depth interviews with alumni who took the course between 1995–2005 and are now working in industry. A qualitative and quantitative analysis of the alumni interviews reveals that former students still highly value what they learned about team work and understanding user needs, but see more value in tools for concept generation, prototyping, and testing after gaining work experience. The results reaffirm the value of engaging students in multidisciplinary design projects as a vehicle for developing the professional skills needed in today’s competitive new product development environment.

Commentary by Dr. Valentin Fuster
2007;():653-662. doi:10.1115/DETC2007-35383.

Methodologies focused on assessing and evaluating the developed learning outcomes and the students’ ability to adequately combine design engineering project work with the knowledge gained from coursework and integrate these by extending it into practical applications exist and are continually evolving. However, it seems that there is still a lot of room for their improvement. In this research, a universally applicable methodical tool, developed in recent years, that is generally useful in knowledge evaluation exercises, was directly applied to the design engineering field. The efforts were focused on developing a model to evaluate the extent to which students have applied their knowledge in various design engineering projects over their undergraduate education. Each component of the proposed model represents a different level of application starting from one’s basic understanding of a concept, the ability of one to relate knowledge and articulate relationships among elements of the fundamentals, and finally culminating into the ability of one to take knowledge and apply it to a novel situation. Rubrics (charts describing learning at different levels of development) were used to evaluate students’ level of knowledge application. The preliminary results of this study proved that the model is quite useful in evaluating the learning process of students via design projects and methods can be developed to customize and maximize it.

Commentary by Dr. Valentin Fuster
2007;():663-670. doi:10.1115/DETC2007-35679.

This paper describes the application of the instrument developed to measure engineering design knowledge gain as a result of a course. The goal for the development of the instrument was the need for an assessment instrument that will be a stable measure of the impact of pedagogic improvements and introduction of new supporting material in the classroom environment. Our ultimate goal is to prepare the environmental conditions and course material that are most conducive for our students in teaching engineering design courses. This paper documents the application process and the results.

Commentary by Dr. Valentin Fuster
2007;():671-678. doi:10.1115/DETC2007-34377.

Following the developments in (Dutch) building practice, where besides specialist skills a design approach is increasingly being asked, the Building Services chair of the Faculty of Architecture, Building and Planning of Technische Universiteit Eindhoven (TU/e) initiated in academic year 2005/06 a multidisciplinary masters project ‘Integral Design’. In this first edition, architecture, building technology and building services students participated. As basis for this project served a learning-by-doing workshop approach, developed and tested with/on experienced practitioners from the Royal Institute of Dutch Architects (BNA) and the Dutch Association of Consulting Engineers (ONRI). The (theoretical) background for the workshops is provided by two PhD projects running within KCBS, entitled ‘Integral design methodology in the context of sustainable comfort systems’ and ‘Integral design methodology in the context of collaborative engineering’. KCBS stands for Knowledge Centre for Building and Systems TNO-TU/e, cooperation between the Netherlands Organization for Applied Scientific Research – core area Built Environment and Geosciences and TU/e. In this paper the results of the first multidisciplinary masters project edition are discussed. At the same time a comparison with BNA-ONRI-KCBS workshops for practitioners is made. The conclusions of this analysis helped us to define improvements for 2006/07 edition of ‘Integral Design’ multidisciplinary masters project, which will take place in the first half of year 2007.

Commentary by Dr. Valentin Fuster
2007;():679-689. doi:10.1115/DETC2007-34491.

Service-learning (S-L) is the integration of academic subject matter with service to the community in credit-bearing courses. In an engineering context, service-learning provides a project-based experience in which students are presented with real clients and their problems, often of immediate need. This paper reflects on three years of service-learning integrated into a first engineering course with approximately three hundred students per year. The costs and benefits of service-learning to students, faculty, and clients are analyzed through several means including traditional teaching evaluations, blind pre- and post-assessments by students and clients, multi-year institutional data regarding student performance, and others. The results indicate that a majority of students personally believe that the described service-learning project is a valuable experience and should be integrated throughout the engineering curriculum. However, the service-learning experience varied significantly across teams, students, and course offerings.

Commentary by Dr. Valentin Fuster
2007;():691-700. doi:10.1115/DETC2007-35683.

The goal of the designed experiment and subsequent analyses presented in this paper was to investigate the power distributions especially with regards to gender in mixed-gender groups engaged in product design decision-making. The task involved determining the set of design criteria pertaining to consumer products with varying gender orientations, and rating the criteria for their importance according to various stakeholder interests. Results indicate that group level acceptance of the contributions was indeed impacted by the type of the product that the decision-making focused on, and that this impact can be attributed to the perceived knowledge levels of the individuals due to their expected familiarity with the product.

Commentary by Dr. Valentin Fuster
2007;():701-707. doi:10.1115/DETC2007-35713.

A Product Design and Manufacturing (PDM) Engineering emphasis has been designed to update a Manufacturing Engineering program at Grand Valley State University. While the program continues to include a major focus on manufacturing it also emphasizes crossing disciplinary boundaries for product design. Graduates of the program are educated to work in all phases of the product development process from concept to customer. The program includes a blend of courses from a variety of disciplines, tieing these together using a sequence of product design courses. Within the courses students are exposed to course work that encourages product oriented design including prototyping. The program redesign described in the paper could also be applied to Mechanical Engineering programs.

Topics: Product design
Commentary by Dr. Valentin Fuster
2007;():709-717. doi:10.1115/DETC2007-35826.

This paper describes barriers to effective collaboration between geographically distributed experts jointly participating in design of medical products. The barriers were observed during a study conducted at a company which produces implantable medical devices such as pacemakers and defibulators, but the issues are typical of most international product producing companies. The company commissioned the study because they experienced serious manufacturing difficulties after moving their manufacturing facility to a new location where labor was less expensive, several thousand miles distant from design facility. The company suspected that the difficulties stemmed from insufficient communication and collaboration between the now distant design engineers and manufacturing engineers, but they lacked a sufficiently detailed understanding of the causes to formulate effective solutions. Electronic tools had not resolved the problems. The study found that the added distance greatly exacerbated many existing design/manufacturing collaboration challenges that occur in most organizations even when the two are located at the same site. Additionally, distance resulted in a decay of familiarity between sites with the people, processes and expertise at the other site. More explicit structure and incentives were needed to help distant team members overcome the added collaboration difficulties created by distance. The study concluded that one while one needs appropriate electronic tools to make it possible for distant design team members to communicate easily, additionally, an organization must provide appropriate processes, incentives and resources to motivate people to collaborate over distance.

Topics: Design , Teams
Commentary by Dr. Valentin Fuster

12th Design for Manufacturing and the Life Cycle Conference

2007;():721-730. doi:10.1115/DETC2007-34425.

This paper presents a review of research in the area of life cycle costing and offers a critique of current commercial cost estimation systems. The focus of the review is on relevant academic research on life cycle cost from 2000 onwards. In addition to this a comparison of the current cost estimation systems is presented. Using the review findings and industrial investigations as a base, a set of mathematical representations for design and manufacturing costs and the introduction of the critical factors is proposed. These are considered in terms of the operational, maintenance and disposal costs to create a method for ascertaining the life cycle cost estimate for complex products. This is presented using as an exemplar, research currently being undertaken in the area of low volume and long life electronic products in the UK defence sector. The benefit of the method proposed is that it aims to avoid the inflexibility of traditional approaches which usually require historical and legacy data to support the cost estimation processes.

Commentary by Dr. Valentin Fuster
2007;():731-739. doi:10.1115/DETC2007-35072.

To estimate profitability of a new system in the conceptual design stage, engineers need to estimate the cost of concept (the cost of the final system developed from each system concept). If engineers have abundant experiences developing similar systems, they can construct a knowledge-base consisting of historical cost data and use it to estimate the cost of concept. However, if the firm is entering a new market, engineers do not have historical cost data to accurately estimate the cost of concept. In this case, engineers need to benchmark similar systems in the marketplace and construct a knowledge-base with the benchmarked information. This paper proposes an approach toward developing a distribution (belief) about the cost of concept using a knowledge-base. The proposed approach retrieves a subset of information from the knowledge-base relevant to estimating the cost of concept, constructs a histogram about the cost of concept, and develops a distribution of the cost of concept. This paper demonstrates the proposed approach by using printers as an illustrative example.

Commentary by Dr. Valentin Fuster
2007;():741-749. doi:10.1115/DETC2007-35074.

The importance of system quality has been increasingly emphasized in the past several decades. In 1987, Malcolm Baldrige National Quality Award (MBNQA) was established to promote quality awareness. Since then, more than 1,100 organizations have applied to the award. One way to measure system quality is by warranty cost. In the automobile industry, for example, warranty costs account for 3–4% of revenue. This paper proposes a framework for managing the warranty cost by setting a target warranty cost for the system and then allocating it to system modules in the conceptual design stage. In the proposed framework, engineers begin by constructing a knowledge-base of past warranty costs. Then regression analysis is used to set the target warranty cost of the new system, and Quality Function Deployment to allocate the target warranty cost to system modules. If detailed design becomes available, engineers can then compare estimated warranty cost with the target and decide whether to further improve reliability or reduce risk of system failure. This paper demonstrates the proposed methodology by using printers as an illustrative example.

Commentary by Dr. Valentin Fuster
2007;():751-760. doi:10.1115/DETC2007-35795.

A cost model is an important tool for product design and material selection. An efficient and effective cost estimation tool is necessary for early design evaluations. In this paper, a cost estimation model is presented that estimates the production cost for metal inert gas (MIG) welded joints. This model determines the cost incurred in fabricating each joint with a detailed explanation of each cost component / driver. Each cost component has been closely analyzed and the major cost components have been included in the cost model. We used this cost model to predict the cost of the forty two different joints joined using MIG welding technique. The results predicted by the MIG welding cost model have been compared to that quoted by an expert welder. Initial results show that the cost model and the expert cost estimates follow a similar general trend. Further study is needed to refine the MIG cost model.

Topics: Metals , Welding
Commentary by Dr. Valentin Fuster
2007;():761-765. doi:10.1115/DETC2007-34142.

This study intends to propose an intelligent system with agent technology in order to realize integration and cooperation of technique preparation process. The agent-based system framework, in which various intelligent agents worked together to perform technique preparation tasks in an autonomous and collaborative way, is put forward. The system consists of three categories of agents and functional definition of each intelligent agent is presented. Moreover, agents communication mechanism and cooperation sequence diagram are proposed. Finally, an intelligent algorithm based on fuzzy comprehensive evaluation is designed to resolve competition conflicts among the agents.

Commentary by Dr. Valentin Fuster
2007;():767-772. doi:10.1115/DETC2007-34152.

In order to realize visualization and intelligence of computer-aided process planning, this paper proposes an intelligent system with the integration of workflow technology and max-min ant system. Workflow modeling technology was applied to represent multi-process routes decision-making problem (MRDP) and a heuristic algorithm based on expert knowledge was designed to construct the directed graph for MRDP. Moreover, a modified ant colony algorithm was proposed to exploit the best solution using improved max-min pheromone strategy and the way of updating pheromone. Finally, an experiment example is illustrated to demonstrate the proposed methodology.

Commentary by Dr. Valentin Fuster
2007;():773-778. doi:10.1115/DETC2007-34258.

The configuration, evaluation and selection of technology chains are some of the most critical tasks, regarding the determination of optimal product and production costs. Nonetheless, these process planning tasks are often still performed in a sequential way and are only unsatisfactorily considered within the process of product development. This paper presents a methodology to overcome these shortcomings, using an integrated configuration and evaluation of technology chains. Its implementation with a standard ERP (Enterprise Resource Planning) System is shown. Basically, the proposed methodology consists of three components. The first one is a product-technology-matrix that specifies the correlations between a company’s products and its available or projected technologies. The second component is a modular generic technology chain model that enables a classification of technologies. A combined quantitative and qualitative evaluation model to calculate and compare different technology chains completes the proposed methodology. These three elements facilitate an appropriate knowledge management concerning products, technologies and their relations. Additionally, a fast configuration of alternative technology chains and a selection of the most adequate ones for newly designed products are addressed, reducing the time of planning processes by almost one quarter. The implementation of the methodology using a standard ERP system is illustrated by two representative use cases.

Commentary by Dr. Valentin Fuster
2007;():779-790. doi:10.1115/DETC2007-35080.

The success of any product in today’s competitive market is dictated by its ability to satisfy the needs of the customers. In this effort, it is important to group similar needs to recognize representative needs, and then identify product requirements that can fulfill these representative needs. One approach to this is to apply Subjective Clustering (SC) to sample data (grouping of customer needs by a sample of customers); however, clusters obtained by SC give only a point estimate of the primary clusters of customer needs by the entire population of customers (population primary clusters). Applying Bootstrap to SC (BS-SC) helps engineers to make inferences on the population primary clusters. In this paper, we randomly pulled out samples of different sizes from both the simulation approach using simulation-generated population data and the empirical approach using experimental population data, and compared the accuracies of SC and BS-SC. Regardless of population sizes, when the sample size was small, BS-SC was more accurate than SC in estimating the population primary clusters. Also, the BS-SC and SC estimates were similar for both simulation and empirical approaches.

Topics: Simulation
Commentary by Dr. Valentin Fuster
2007;():791-805. doi:10.1115/DETC2007-35120.

Previously in this forum, we validated a product modularity measure and modular product design method and developed a way to extend these product modularity fundamentals to encompass the impacts of assembly process similarity and dependency. This paper expands the life-cycle process-based modularity representation to the manufacturing process and beyond. Modularity representation, including similarity and dependency, is an important aspect of modular product design and it is imperative for realizing the promised cost savings of modularity. The component-component similarity matrix is used to cluster components with similar manufacturing processes into one module. Similarities are based on component processing codes that represent their manufacturing attributes. Clustering these manufacturing process similarities leads to cost savings through module-wide sharing of process plans, manufacturing tools, and equipment, and the reduction of manufacturing tool and equipment changes during manufacturing. The component-component dependency matrix is based on physical interactions among the components that affect the material, shape, size, surface finish etc. of the components, and therefore affect the component manufacturing processes. If components are independent of other components not in the same module with respect to these physical interactions, the redesign of components in one module will not cause a cascade of design and manufacturing process plan changes for components not in the same module. A fishing reel example is used to illustrate the application of manufacturing process similarity and dependency representations, in association with a product modularity measure and a modular product design method, to form manufacturing process-based component modules. The work in this paper establishes how to represent manufacturing process similarity and dependency for use in product modularity decision making. The use of such modules improves the efficiency of manufacturing process planning, and reduces design and manufacturing process costs.

Topics: Manufacturing
Commentary by Dr. Valentin Fuster
2007;():807-818. doi:10.1115/DETC2007-35212.

Globalization pressures lead companies of the capital-intensive goods industry to follow the example of the automotive industry and develop global platform-based products. One of the most difficult task is to cover all kinds of local standards, laws, and regulations within the platform. Supplementary strong variations in the purchasing power of customers, education of work forces, and availability of technology or mere fashions in local markets have an impact on regional business processes. Thus, undesirable and unplanned redesigns become necessary during the localization of a global product family into its regional markets. Hence, this paper discusses a platform process, which incorporates life cycle and value chain thinking into the product structuring process. This process is supported by a Component Box platform model offering robustness for component re-use and flexibility for local differentiation. Moreover it facilitates the collaborative product development by an enhanced transparency throughout the entire process.

Commentary by Dr. Valentin Fuster
2007;():819-828. doi:10.1115/DETC2007-35316.

Recently, awareness of Corporate Social Responsibility (CSR) has been raised and various environmental regulations have spread in many countries. Under this situation, manufacturers of process production, production information management systems are required that can archive and retrieve data not only of final products and raw materials but of chemical substances contained, intermediate products and wastes generated, and energy consumption during the production. However, management systems and product models currently used for assembly production do not fit the above requirement. To solve the problem, first, an object-oriented process-product model was designed which can represent these data and can be easily implemented on commercial ORDBMS. Second, traceability functions of explosion and implosion covering chemical substances, intermediate products, wastes and energy were developed on the ORDBMS. Third, a generic environmental law model was designed which can represent restrictions of various environmental regulations in a uniform way. Finally, a conformance checking function for environmental regulations was developed by combining the generic environmental law model with the process-product model. The effectiveness of the models and functions was verified by applying them to full-scale production data of functional polymer films and checking its conformance to RoHS and EuP directives.

Commentary by Dr. Valentin Fuster
2007;():829-837. doi:10.1115/DETC2007-35615.

The application of lean manufacturing principles has improved the production flow of manufacturing companies across the globe. In a similar vein, environmentally conscious design has been an increasingly important avenue of research which similarly seeks to reduce waste and thereby mitigate environmental impact. An analysis of the curbside municipal solid waste (MSW) and recycling collection process from a lean manufacturing standpoint reveals numerous non-value added activities which can be eliminated or reduced and value-added activities which can be made more efficient. Environmental America Inc. (EAI) has proposed a collection process which will improve the overall material flow through the use of a collection vehicle specializing in the combined collection of raw waste and recyclable waste. This collection vehicle, combined with localized, low-impact material offloading facilities has the potential to revolutionize the curbside collection process. Our research supports this vision by configuring the truck layout and process operations, as discussed in this paper.

Topics: Manufacturing
Commentary by Dr. Valentin Fuster
2007;():839-849. doi:10.1115/DETC2007-35859.

Firms today increasingly seek to leverage product platforms via derivative product versions of the base platform, but successfully doing so is a significant challenge. Numerous enablers are required, such as robust product development processes, effective and well trained organizations, R&D activities that are aligned to support product strategies, and a clearly defined corporate strategy. In derivative product development firms struggle to identify the optimum derivatives to develop and bring to market. Evaluating which feature to improve upon, which technologies to incorporate, which markets to pursue, and ultimately which derivative product to develop is an uncertain proposition that has significant implications to future profitability. There majority tools and processes that exist to provide guidance in these activities largely focus on platform development strategies and decisions. A limited number are known to apply specifically to derivative products, after the platform has been design and implemented. This work proposes a derivative product concept generation and selection framework that extends the design for variety methodology to analyze derivative product alternatives.

Commentary by Dr. Valentin Fuster
2007;():851-859. doi:10.1115/DETC2007-34255.

Topology optimization is a useful design tool, but it often yields layouts difficult to manufacture without considerable post structural modification. As a result, its structural performance can be significantly deteriorated. To minimize the undesirable postprocessing, we aim to develop a manufacturability-oriented compliance-minimizing topology optimization using a ground beam model incorporating additional zero-length elastic joint elements. In the present formulation, design variables control the stiffness of zero-length elastic joints, not the stiffness of beams. Because joint stiffness values at the converged state can be utilized to select candidate assembly locations, the technique is extremely useful to design multi-piece frame structures. An optimal layout is also extracted based on the stiffness values. Because structural properties of ground beams can take only on discretely available values or remain unchanged for optimization process, no post structural modification is required in an actual manufacturing step.

Commentary by Dr. Valentin Fuster
2007;():861-870. doi:10.1115/DETC2007-34310.

For parts suppliers in the manufacturing industry, the process of preliminary production preparation and the subsequent calculation of offers are critical business activities. A vital part of production preparation is the design of fixtures and tooling necessary for many processes of metal forming. In order for a company to give quick responses to customer enquiries or changes in prior specifications, it would be highly beneficial with a degree of automation in this design process. This implies the development of a computer based system able to capture existing design procedures and associated knowledge for the classes of tooling required for the forming process. In this work, an implementation for the rotary draw bending of aluminum tubing has been done to exemplify how to develop an automated design system. The system is based on heuristic knowledge developed over many years of practical experience, knowledge analytically derived from fundamental theory found in scientific literature, and rules based on empirical data from trial manufacturing. The system applies knowledge to a given specification that a skilled engineer otherwise would do manually. The system output can be used to evaluate whether a tube is producible. The main idea behind the system is to use knowledge objects containing information on inputs, outputs, constraints and what software are used to implement the knowledge pieces. This approach makes the system highly flexible and allows for multiple types of knowledge that might overlap. When an offering calculation is wanted, the system is set to run applicable knowledge objects for presented input data. Other objects are run when an accurate calculation for detailing is wanted for a more detailed set of input data. The system is built on readily available commercial software packages connected with a simple Visual Basic .Net program. When building a system of this kind, it is essential that the knowledge documentation and structure be such that the functions of the system can be easily understood by the users of the system and by future developers. Aspects of user friendliness, transparency and scalability are addressed in the summary of this paper.

Commentary by Dr. Valentin Fuster
2007;():871-879. doi:10.1115/DETC2007-34764.

By combining a Computer Aided Industrial Design (CAID) tool with a Computer Aided Tolerancing (CAT) tool, concurrent work between two related, but in industry often separated, areas with correlated product design features is facilitated. This paper presents an analysis tool that allows the creation and evaluation of split-lines in design concepts with respect to geometrical robustness and aesthetics. The aim with the analysis tool is to create products that are insensitive to manufacturing variation with the industrial design intent preserved. Since the split-lines are clues to detecting variation in assembled products, as well as part of the design language and the characterization of the product, it is important to work with these issues concurrently. The platform concept has been increasingly adopted in companies which, in many cases, provide an inheritance of the locating schemes, thus affecting the geometrical robustness of the concept, between models and sometimes even brands. This means that the parts creating an assembled product need to be designed in such a way that they satisfy the locating scheme configuration to achieve a geometrically robust solution. The functionality of the analysis tool has been demonstrated on an automobile body.

Commentary by Dr. Valentin Fuster
2007;():881-889. doi:10.1115/DETC2007-35322.

An industrial design concept can be adapted to manufacture and assembly by striving for visual design properties that are economical and time-efficient to produce according to specifications. One aspect of this is to assess whether the concept will be visually sensitive to distortions in structure, form, colour, gloss and texture. Visual appearance problems are often unrelated to the actual quality or functionality of a product. In the eyes of the customer, they may however serve as intrinsic quality cues, perceptions of quality attributes acquired by observing the product before purchase. Through interviews conducted at an automobile company and a mobile telecom company, factors considered important for the visual quality appearance of their products were identified. These factors are divided into groups, and examples are given. The result is an overview of visual quality appearance aspects, which demonstrates that design for perceived quality can be a trade-off between quality cues as deliberately placed styling features and quality cues stemming from complex assembly variation conditions.

Commentary by Dr. Valentin Fuster
2007;():891-900. doi:10.1115/DETC2007-35688.

This paper presents the methods to move assembly variation analysis into early stages of aircraft development where critical partitioning, sourcing, and production decisions are often made for component parts that have not yet been designed. Our goal is to identify and develop variation prediction methods that can precede detailed geometric design and make estimates accurate enough to uncover major assembly risks. With this information in hand, design and/or manufacturing modifications can be made prior to major supplier and production commitments. In addition to estimation of the overall variation, the most significant contributors to assembly variation are also identified. In this paper, a generic framework for prediction of assembly variation has been developed. An efficient, top-down approach has been adopted. Instead of taking measurement everywhere, the variation analysis starts with airplane level requirements (e.g. load capabilities, orientation of horizontal/vertical stabilizers), and then assembly requirements (mainly geometric dimensioning and tolerancing callouts, quantifiable in Quality Control) are derived. Next the contributors to a particular assembly requirement are identified through Datum Flow Chain analysis. Finally, the major contributors are further characterized through a sensitivity study of Metamodels or 3D variation analysis models. A case study of a vertical fin has been used to demonstrate the validity of the proposed framework. Multiple prediction methods have been studied and their applicability to variation analysis discussed. Simplified design simulation method and Metamodel methods have been tested and the results are reported. Comparisons between methods have been made to demonstrate the flexibility of the analysis framework, as well as the utility of the prediction methods. Results of a demonstration test case study for vertical fin design were encouraging with modeling methods coming within 15% of deviation compared to the detailed design simulation.

Topics: Manufacturing , Design
Commentary by Dr. Valentin Fuster
2007;():901-911. doi:10.1115/DETC2007-34282.

Globalization is motivated by the potential for cost reduction through access to lower labor costs, as well as by the potential for increased sales through access to new markets. A review of cost data indicates the potential savings related to labor as compared to the potential additional costs related to raw materials, shipping, and tariffs. A logistics cost model is then presented that considers purchase cost, shipping cost, inventory holding cost, order cost, and stock out cost subject to demand uncertainty. Four different design for manufacturing and assembly (DFMA) guidelines are then analyzed for a single product case study: 1) minimize total shipping costs, 2) source components globally, 3) standardize product platforms and modularize options; and 4) regionalize final assembly. The analysis of these guidelines indicates that global sourcing of components led to the most significant cost reductions, but that all guidelines were significant when considering logistics subject to uncertain demand.

Topics: Manufacturing , Design
Commentary by Dr. Valentin Fuster
2007;():913-918. doi:10.1115/DETC2007-34586.

This paper describes the design and development of surfboard-fins as products for marine sports. The purpose of the research is to improve turning ability by reducing drag force on the fins. Design modification was conducted, based on conventional fins, to increase turning ability and lower drag force. Three modified center-fins and three modified side-fins were selected. The design process involved 3D-CAD fin configuration models created with ProENGINEER Wildfire and utilized computational fluid dynamics from 3D-CAD data. Solid forms, which are required in this study since fin configuration is streamlined, are difficult to use in 3D-CAD software. Therefore, a surface element software (NURBS) developed by a propeller maker in Japan was used and the fins were converted into solid forms. After producing the fin models, the performance of factors such as turning ability and drag force were calculated using computational fluid dynamics. A flow experiment was conducted using a flow water tank in Western Hiroshima Prefecture Industrial Research Institute. This report commences with an explanation of the modifications on the fin models to improve turning ability and lower the drag force. It is then followed by the flow analysis using computational fluid dynamics software and the flow experimental results.

Commentary by Dr. Valentin Fuster
2007;():919-928. doi:10.1115/DETC2007-34868.

Global companies realize the importance of collaborative design, or workshare, to develop products not only to target to a single market, but to sell them to the entire world. Workshare not only incorporates diverse customer values into the product development, but also introduces challenges in managing work distributions among global teams. As a result, the authors have developed a Distributed Risk Framework to quantify risk based on rework to facilitate workshare planning [5] [6]. The risk framework has been applied to several industry projects and it received positive feedback from the potential users of these pilot applications. To verify the risk results analytically, this paper seeks for statistical evidence to confirm the key assumption that motivates the development and the usage of the framework, with the assumption being that more distributed work results in a greater risk of rework. This paper begins with an overview of the risk framework followed by the steps of using actual rework data from the International Vehicle Company (IVC) to confirm the framework assumption. As a summary, this paper presents the contributions of the risk framework and the barriers to extend it to other distributed product development projects.

Commentary by Dr. Valentin Fuster
2007;():929-941. doi:10.1115/DETC2007-34991.

Manufacturers at present face new circumstances in terms of consumer services and serious environmental problems. An effective way to deal with these circumstances may be to pursue qualitative satisfaction rather than quantitative sufficiency. The aim of this paper is to demonstrate the effectiveness of Service Engineering, including the service design process model, to increase customer satisfaction. The redesign of services offered by a global warehouse manufacturer is used as an example of the application. Four redesign options, such as rapid delivery of components and a robust electrical system, were generated. The effectiveness of the method was demonstrated by the application.

Topics: Design , Computers
Commentary by Dr. Valentin Fuster
2007;():943-952. doi:10.1115/DETC2007-35812.

The acceleration of product development cycle continues to be a significant challenge for manufacturing firms around the world. This paper describes a task planning method for minimizing trial and error to reduce the development time in large-scale and complicated product development at the early stage of product development. The proposed method matches the group of product components according to geometry and determines the development sequence of each component to minimize the amount of feedback information across task groups. The method applies as evaluation index for task prioritization the product-sum of engineering interaction among components and worth of each component, the “worth flow.” The paper shows with an example of the generic hair drier with simple mechanical structure that this method contributes to the reduction of the size of task group by 22% and amount of information required for setting the interface links by 65% compared to the conventional planning methods.

Commentary by Dr. Valentin Fuster
2007;():953-961. doi:10.1115/DETC2007-35671.

Product take-back and remanufacturing systems are difficult to implement cost-effectively. Two contributing factors to this problem are the complex nature of the interrelationships among components, and their high degree of variability. Legislated take-back mandates have made it imperative for manufacturers to realize when there is value to be recovered in components and when there is not. This paper proposes a component criticality method to help ascertain this remaining value. We also develop a metric that measures the randomness or variability that a reuse alternative imposes on the remanufacturing system. A case study on washing machines illustrates how the two measures can be incorporated into a design decision model, can help reduce the complexity of reuse operations, and result in a superior design solution.

Commentary by Dr. Valentin Fuster
2007;():963-968. doi:10.1115/DETC2007-35841.

Widespread IT application leads up to the idea of integrating all the information related with products. It is the ultimate goal to design a product creatively and automatically acquiring all the updated information through close interaction with Product Life-cycle Management (PLM) system starting from conceptual design phase. In this paper, Product Genetic Engineering (PGE) concept for innovative design automation is introduced, and extended to Product Life-Cycle Genetic Engineering (PLCGE) which has genes for downstream processes and can interact with all the real-time information through PLM, and so provides real-time support for PGE decision-making. A basic framework for PLCGE is proposed in which the product development can be divided into two main phases: the generation of product “genome” and the growth of the “genome” into its physical form. In the former phase, the product genome originates from and serves as an extension to human genome, and forms a complete genome through design process dealing with life-cycle factors. In the latter phase, the product genome acquires “protein” to grow inside its mother body (the factory), and PLM system acts as an “umbilical cord” between the product genome and its mother body. Finally, a case study of PLCGE application in Mass Customization is made for validity of PLCGE.

Commentary by Dr. Valentin Fuster
2007;():969-979. doi:10.1115/DETC2007-35848.

Design reviews are one of the most established product-development project management techniques to identify and eliminate errors in product design before they physically manifest themselves either in a prototype or in the final product. Design reviews are typically embedded within an overall product-development project management process consisting of multiple stages separated by decision gates. The specific goal, structure and content of a design review depend upon the stage and time at which it is performed. In the process of working with a number of large companies on their technology and product development processes we observed that the actual practice of design reviews often falls well short of the companies’ own stated objectives. We examine the reasons for this in our paper, the chief among them being the often misleading application and lack of clarity and brevity in the review process. These problems can be clearly highlighted and rectified by the application of the CVCA and FMEA tools to the design review process itself. Thus, design reviews can be made more efficient and effective and made to count!

Topics: Design
Commentary by Dr. Valentin Fuster
2007;():981-988. doi:10.1115/DETC2007-35881.

Technology life cycles affect a product manager’s ability to sustain systems through their manufacturing and field lives. The lack of availability of critical parts and technologies poses a challenge not only to the acquisition community, but to customers of products that must be maintained for long periods of time. Technology obsolescence has an especially serious impact on systems that have significant electronics content because electronic parts are quickly obsoleted in favor of newer, higher performance components. In this study, market availability data was analyzed for operational amplifiers, a technology integral to most electronic products, and for flash memory devices. Procurement lifetimes are shown to have shrunk since operational amplifiers emerged on the market. Algorithms for forecasting electronic part obsolescence are proposed and the ramifications of electronic part obsolescence on product design planning are discussed.

Topics: Product design
Commentary by Dr. Valentin Fuster
2007;():989-997. doi:10.1115/DETC2007-34146.

Modular fixtures are one of the important aspects of manufacturing. This paper presents a desktop VR system which provides a training environment that allows participants to interact naturally with digital objects and configure fixture system instructively. The modular fixture design procedure is proposed. It assists the trainees to make the feasible design decisions and master the necessary principles involved in modular fixture design as well. A hierarchical data model is proposed to represent the modular fixture assembly. Based on this representation, the user can manipulate the virtual models precisely in VE during the design and assembly processes. The assembly relationship between fixture elements is analyzed and the assembly operation process is discussed. Moreover, a Case Based Reasoning (CBR) approach for useful cases retrieval is presented. It provides the trainee with design references to achieve a better design. The case study has demonstrated the functionality of the proposed training system.

Commentary by Dr. Valentin Fuster
2007;():999-1006. doi:10.1115/DETC2007-34251.

Products are traditionally designed mainly to meet functional requirements with rarely considering maintenance issues for products life-cycle. This paper presents an approach to nondestructive selective disassembly planning for the product maintenance. The approach is based on the part disassemblability analysis. It provides a way to support interactive selective disassembly task planning in dynamic manufacturing environments considering the operation space in applications. To support design at the early stage of product development, this paper also discusses de-manufacturability and maintainability analysis based on the proposed approach. Examples are provided to verify the developed method.

Topics: Maintainability
Commentary by Dr. Valentin Fuster
2007;():1007-1016. doi:10.1115/DETC2007-34694.

Tool accessibility is a critical issue for generating a complete fixture setup plan to reduce production setup time. Previous fixture design systems rarely consider the assembly tool accessibility. Current methods of assembly tool accessibility analysis mainly depend on simulation-based or user-interactive approaches which rely on users’ judgment. This paper presents a new approach to tool accessibility analysis for fixture setup planning. The fixture workspace around a tool is represented by a newly defined global accessibility sphere with depth of a truncated half-line. The assembly tools are modeled as five articulated parts to fully describe the tool characteristics. Accessibility analysis is executed to verify assembly tools’ feasibility applied on a fastener. In particular, both tool motion and tool placement constraints during tool applications are integrated into the tool geometric reasoning. The example demonstrates the fast computing speed and intuitive simulation of several assembly tools in fixture setup planning.

Commentary by Dr. Valentin Fuster
2007;():1017-1027. doi:10.1115/DETC2007-34804.

Simulations of Assembly/Disassembly (A/D) processes covers a large range of objectives, i.e. A/D sequencing, path finding, ergonomic analysis [[ellipsis]], where the 3D shape description of the component plays a key role. In addition, the A/D simulations can be performed either from an automated or interactive point of view using standard computer equipment or through immersive and real-time simulation schemes. In order to address this diversity of configurations, this paper presents a simulation framework for A/D analysis based on a new simulation preparation process which allows a simulation process to address up to two types of shape representations, i.e. B-Rep NURBS and polyhedral ones, at the same time, thus handling efficiently the configurations where 3D shape representations of assemblies play a key role. In order to illustrate the simulation preparation process some specific steps are addressed. To this end, the automatic identification of contacts in a 3D product model and their corresponding list is described. After this first stage of identification, an interpretation of the results is needed in order to have the complete list with the mechanical contacts for a product. During the preparation process, three major stages of the framework are detailed: model tessellation, surface merging and contacts identification. Our framework is based on STEP exchange format. The contacts are related to basic geometrical surfaces like: planes, cylinders, cones, spheres. Some examples are provided in order to illustrate the contributions of the proposed framework. This software environment can assist designers to achieve a satisfactory assembly analysis rapidly and can reduce the lead-time of product development. Further consequences of the present work is its ability to produce models and treatments that improve integration of assembly models in immersive environments taking into account of the haptic and visual models needed.

Commentary by Dr. Valentin Fuster
2007;():1029-1039. doi:10.1115/DETC2007-35804.

Recent legislative and social pressures have driven manufacturers to consider effective part reuse and material recycling at the end of product life at the design stage. One of the key considerations is to design and use joints that can disengage with minimum labor, part damage, and material contamination. This paper presents a unified method to design high-stiffness reversible locator-snap system that can disengage non-destructively with localized heat, and its application to external product enclosures of electrical appliances. The design problem is posed as an optimization problem to find the orientations, numbers, and locations of locators and snaps, and the number, locations and sizes of heating areas, which realize the release of snaps with minimum heating area and maximum stiffness, while satisfying any motion and structural requirements. Screw Theory is utilized to pre-calculate a set of feasible orientations of locators and snaps, which are examined during optimization. The optimization problem is solved using Multi Objective Genetic Algorithm (MOGA) coupled with structural and thermal FEA. The method is applied to two-piece enclosure of a DVD player with a T-shaped mating line. The resulting Pareto-optimal solutions exhibit alternative designs with different trade-offs between structural stiffness during snap engagement and area of heating for snap disengagement. Some results require the heating of two areas at the same time, demonstrating the idea of a lock-n-key.

Topics: Heat , Design , Stiffness
Commentary by Dr. Valentin Fuster

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