ASME Conference Presenter Attendance Policy and Archival Proceedings

2012;():i. doi:10.1115/ESDA2012-NS3.

This online compilation of papers from the ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis (ESDA2012) represents the archival version of the Conference Proceedings. According to ASME’s conference presenter attendance policy, if a paper is not presented at the Conference, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.

Commentary by Dr. Valentin Fuster

Advanced Composite Materials and Processing

2012;():1-10. doi:10.1115/ESDA2012-82060.

A micromechanics-based approach for the derivation of the effective properties of periodic linear elastic composites which exhibit strain gradient effects at the macroscopic level is presented. At the local scale, all phases of the composite obey the classic equations of tridimensional elasticity, but, since the assumption of strict separation of scale is not verified, the macroscopic behavior is described by the equations of strain gradient elasticity. The methodology uses the series expansions at the local scale, for which, higher-order terms (which are generally neglected in standard homogenization framework) are kept, in order to take into account the microstructural effects. All these terms are then obtained by solving a hierarchy of higher-order elasticity problems with prescribed body forces and eigen-strains whose expression depends on the solution at the lower-order. An energy based micro-macro transition is then proposed for the change of scale and constitutes, in fact, a generalization of the Hill-Mandel lemma to the case of higher-order homogenization problems. The constitutive relations and the definitions for higher-order elasticity tensors are retrieved by means of the “state law” associated to the derived macroscopic potential. It is rigorously proved that the macroscopic quantities derived from this homogenization procedure comply with the equations of strain gradient elasticity. As an illustration, we derive the closed-form expressions for the components of the gradient elasticity tensors in the particular case of a stratified periodic composite. For handling the problems with an arbitrary microstructure, a FFT-based computational iterative scheme is proposed whose efficiency is shown in the particular case of composites reinforced by long fibers.

Commentary by Dr. Valentin Fuster
2012;():11-19. doi:10.1115/ESDA2012-82096.

This work was performed in the frame of the european project INFUCOMP. This paper focuses on the development of a viscosity model for the epoxy systems Hexcel RTM6 and Cycom 890RTM, and the associated experimental data sets. A new modelling approach was developed based on the use of reference viscosity as a state variable instead of the conventionally used degree of cure. The new approach focuses on the time-temperature window of infusion processes, thus yielding higher accuracy results and a more efficient representation of rheological behaviour. Furthermore, the model can be integrated analytically under isothermal conditions, which carries advantages with regard to both parameter estimation and implementation within the context of process simulation. The model was then implemented in PAM-RTM simulation software. To do so, not only the aging of the resin had to be taken into account, but also the transport of this information with the flow. Last verification simulation tests were performed with LCM simulations.

Commentary by Dr. Valentin Fuster
2012;():21-26. doi:10.1115/ESDA2012-82149.

The herein paper will aim to approach, both theoretically and experimentally, the effective thermal conductivity of self-manufactured hybrid polymeric composites made up from random, long E-glass fibers and different particles (e.g. ceramic/metallic) embedded in different volume fraction into a polymeric matrix.

The theoretical approach will be based on micromechanical models developed for each structure and on numerical simulations based on the well known mean field homogenization scheme of Mori-Tanaka applied as a multi-step procedure, the conditions imposed for the thermal analysis being the same as used in the experimental settings — a monotonic rise of temperature up to 150°C. Furthermore, extended analysis will be carried on the hybrid structures under the study using few theoretical models developed within the literature to aid the comparison and characterization.

The experimental measures were carried out using a thermal conductivity analyzer C-THERM TCi from Mathis Instruments Ltd.

The theoretical predicted and experimentally retrieved values will be further compared to identify and size the influencing factors on the data as well as on setting a protocol for further composite structures with tailoring thermal properties.

Commentary by Dr. Valentin Fuster
2012;():27-32. doi:10.1115/ESDA2012-82185.

The importance of dynamic mechanical analysis (DMA) as a research tool in the study of polymeric composite structures behavior has been already demonstrated in the literature. Many papers were approaching the relaxation phenomenon within the polymer based composite structures and thereby their behavior under various conditions of stress and temperature. Supplementary, the effect of fillers geometry, orientation and volume fraction have been extensively approached while considering the micromechanical level and their role in the mechanical properties were suitable stated. Hybridization of two different fillers has proven to an effective method in material design allowing their developers to tailor their properties according to the application driven imposed requirements.

The herein paper attempts to present a comparative study centered on the development and characterization of a hybrid polymeric composite structures made up from different combinations of carbon and glass fibers by evaluating their dynamic mechanical properties.

The samples were measured using the Dynamic Mechanical Analyzer (DMA) from NETZSCH-DMA 242 C, in the 3-point bending mode, nitrogen atmosphere, at a scanning rate of 3 K/min from −40 to 180° C with a fixed frequency of 1 Hz. Storage and loss modulus, loss tangent were recorded as function of temperature both on longitudinal and transverse direction of the unidirectional carbon fibers, in two consecutive heating cycles. A reference sample was set up to aid the comparison analysis, made entire from one filler type.

The effect of the fillers type, fillers relative volume fraction and temperature on the storage and loss moduli will be deeply investigated.

Commentary by Dr. Valentin Fuster
2012;():33-37. doi:10.1115/ESDA2012-82235.

A High-density polyethylene has been used for buried plastic pipe production for over a decade. The structural performance of these pipes mainly depends on the viscoelastic properties of using materials. The aim of this study is to determine the creep behavior of PE100 material under constant tensile and flexural stress within 24 hours. In both tests, large deformation occurs within the first 1000 seconds and then very little or no deformation is observed. Primary and secondary creep stages have also been observed. At highest stress level, maximum strain is 5%, approximately.

At the flexural creep experiments, modulus of the material has been obtained from total deflection value at the end of 24 hours by using three point bending experiment under constant load. Large deflection occurs within in first 1000 seconds, after that, continues to increase slowly. Maximum strain is about 2%. The material exhibits linear viscoelastic response to 8 MPa stress level.

Commentary by Dr. Valentin Fuster
2012;():39-40. doi:10.1115/ESDA2012-82482.

Carbon Black (CB) and carbon nanotubes (CNTs) are both nano-scale forms of graphitic carbon (CB presents itself as nano-spheres of carbon). Both have excellent electrical, thermal and mechanical properties, what why they are often used in composite fabrication.

Commentary by Dr. Valentin Fuster
2012;():41-49. doi:10.1115/ESDA2012-82544.

Automated tape placement (ATP) is a process recently developed for the production of large parts (plates, shells) made of thermoplastic composites. In ATP a tape is placed on the previous ply and welded by a local heating and pressure to build up a laminated structure. The numerical modeling of such a process is a challenging issue since the thermal history of each ply is different, depending on its position within the structure. The evaluation of residual stresses is particularly important for determining the deformed shape of the piece at the end of the process. A numerical model based on the Proper Generalized Decomposition is proposed. The solution of the 3D thermal problem is performed first. Thermal contact resistances are in particular introduced in order to model the imperfect heat conduction at the interface of two neighboring plies. The computed temperature field is then introduced in the mechanical model considering a thermo-elastic behavior for the material. An incremental approach is therefore used on a control volume in order to compute the evolution of the stresses within the laminated structure during the process.

Commentary by Dr. Valentin Fuster
2012;():51-56. doi:10.1115/ESDA2012-82548.

The degradation of polymers has a great influence on their characteristics. Two kinds of processes may be distinguished, physical and chemical. Both are strongly linked. The degradation may be for example induced by UV irradiation, thermal ageing, physico-chemical attacks (water, oxygen, etc.), and mechanical stress. To investigate the thermal ageing effect on the large deformation stress-strain behaviour of PE100, tensions tests were conducted on this material samples submitted to a temperature of 90°C during different hold times. These tests show that thermal ageing leads to an increase of the mechanical properties like the Young Modulus, the yield stress and the stress at break. We show in our work, by different investigations techniques like X-rays diffraction, Transform Infrared Spectroscopy (FTIR), that this increase of mechanical properties is not due to a chemical changes but is due to an increase of the rate of the crystallinity commonly designated by the post-crystallization phenomena.

Commentary by Dr. Valentin Fuster
2012;():57-61. doi:10.1115/ESDA2012-82549.

Drilling composite materials is one of the primary processes of manufacturing industrial structures. The ultimate goal towards on-line monitoring of composites drilling is in order to produce damage free high quality drilled holes. In the present investigation, the acoustic emission (AE) technique was applied for monitoring the drilling-induced delamination. Delamination is major damage mechanisms in glass fiber reinforced plastic (GFRP) laminates correlated with the thrust force during drilling process. By feature extraction of AE time domain, root mean square (RMS) is selected as the best parameter to monitor thrust force variations. The experimental results show that AE is very sensitive to the response of the drilling conditions.

Commentary by Dr. Valentin Fuster
2012;():63-67. doi:10.1115/ESDA2012-82581.

Variability in fiber architecture and content introduces randomness in transport and mechanical properties of textile reinforcements and composites. Assessment of robustness of both manufacturing processes and composite parts require to link fabric variability to dominant properties. Irregular injection flow patterns or defects in the final products often occur due to the high variability in the fibrous media. Therefore, manufacturing robustness and part reliability have to be studied to avoid trial and error procedures. This study focuses on spatial variability in the fiber volume fraction and architecture and their influence on permeability of fiber reinforcements and mechanical performance of textile composite, relating these important properties to variation in reinforcement architecture. Methods to capture experimentally and model numerically the fabric randomness are presented and illustrated on typical non-woven fabrics. An efficient numerical approach is presented for the simulation of mold filling process with random fibrous permeability as input. Numerical examples for different injection schemes are presented to demonstrate the ability of the current approach in predicting the variability in mold filling results.

Commentary by Dr. Valentin Fuster
2012;():69-74. doi:10.1115/ESDA2012-82670.

Drilling is a dynamic process which causes some defects in composite materials such as delamination, fiber pull out and matrix cracking. Because of non-stationary behavior of drilling process, using online method to monitor these damage mechanisms is inevitable. In this paper, acoustic emission signals and wavelet analysis are applied to monitor drilling action from entry to exit. The results show that the selected monitoring indices from the time domain parameters and wavelet packet coefficients are capable of detecting the drilling stages and damage mechanisms during the process effectively.

Commentary by Dr. Valentin Fuster
2012;():75-82. doi:10.1115/ESDA2012-82686.

Free vibration analysis of sandwich beam with a viscoelastic core based on the extended high-order sandwich panel theory approach is presented. The effects of transverse shear and core compressibility are of high importance in sandwich structures, having an influence on the entire structural behavior especially in vibrations. For applications involving stiffer cores, the high-order sandwich panel theory (HSAPT) cannot accurately predict the shear and axial stress distributions in the core. Thus, by using the “Extended High-Order Sandwich Panel Theory” (EHSAPT), the in-plane rigidity of the core is considered in addition to the compressibility of the core in the transverse direction. The novelty of this theory is that it allows for three generalized coordinates in the core (the axial and transverse displacements at the centroid of the core, and the rotation at the centroid of the core) instead of just one (mid-point transverse displacement) commonly adopted in other available theories. The mathematical formulation uses the Hamilton principle and includes derivation of the governing equations along with the appropriate boundary conditions. The formulation uses the classical thin plate theory for the face sheets and a two-dimensional elasticity theory or equivalent one for the core. In addition, Young modulus, rotational inertia, and kinetic energy of the core are considered and core is assumed as an orthotropic viscoelastic material. The analysis is applicable for any types of loading scheme, localized as well as distributed, and distinguish between loads applied at the upper or the lower face. The obtained results are compared with recent research published by the present authors which was done numerically by using FEM on viscoelastic sandwich beam and the corresponding results of other previous researches. The influence of material properties, face layup and geometry effect on natural frequencies of composite sandwich beams are investigated.

Commentary by Dr. Valentin Fuster
2012;():83-91. doi:10.1115/ESDA2012-82722.

We present modeling and simulation of air void formation in composite materials manufactured by the Resin Transfer Molding (RTM) process. The prediction of air void formation has been an important topic because air voids in composite materials deteriorate the mechanical properties of the part.

It has been found by experimental observations that the void content, for a specific preform, can be correlated with capillary number which is the ratio of the viscous force and the surface tension. It is still difficult, however, to predict the void formation without experimental measurement. Moreover, the capillary number may not be the exclusive parameter in practical cases, because the modeling by the capillary number does not work well for large and complex parts.

In this context, we propose a mathematical model to predict the air void formation in the channel which is on open gap between fiber tows and inside the fiber tow. Moreover, the void formation in the warp and the weft are modeled separately by considering the tow orientation with respect to the flow direction. We also modeled two other important phenomena, namely air void compression or expansion, and void migration. To validate the model, void content was experimentally measured by injecting an electrically conductive liquid into a preform. The voltage drop was correlated with the air void content considering the air as a non-conducting material. For a unidirectional fabric, a good agreement was obtained between the model prediction and the experimental result.

Commentary by Dr. Valentin Fuster
2012;():93-99. doi:10.1115/ESDA2012-82838.

Due to the tendency to increase the velocity of high-speed trains, concerns about their probable events have increased. Since train’s frontal nose is the first part of the train which is damaged at the frontal impact, specific attention should be paid to the design of this part. In this study an effort has been conducted to design a nose with light weight which can absorb maximum amount of energy that is possible when a frontal collision occurs. To this aim and with attention to aerodynamic considerations, application of aluminum honeycomb (HC) sandwich panel as an internal layer of train nose has been studied. This paper includes two main parts. The first part is dedicated to the simulation of aluminum HC sandwich panel with both shell and solid elements under dynamic crush loads. While the frontal collision of nose with different internal layer thicknesses of HC has been simulated in the second part and an optimum thickness has been proposed based on the generated results. It has been demonstrated that for all thicknesses amount of energy absorption has been increased at least 35%. Finite element method using LS-DYNA commercial package has been used for the numerical simulation. The results have been validated with available experimental results and acceptable agreement has been observed.

Topics: Aluminum , Trains
Commentary by Dr. Valentin Fuster
2012;():101-105. doi:10.1115/ESDA2012-82975.

The presented paper deals with study of thermo-physical properties of cast complex alloyed nickel based superalloys IN713LC, IN738LC and IN792-5A. In this work the technique of Differential Thermal Analysis was selected for acquisition and comparison of the phase transformation temperatures. The samples taken from superalloys in as received state were analysed at heating and cooling rates of 1, 5, 10, and 20 K/min using the experimental system Setaram SETSYS 18TM. Moreover, the transformation temperatures for zero heating/cooling rate were calculated. Based on a comparison of these temperatures it is possible to make the following conclusions: (i) The alloy IN792-5A has the highest temperature of solubility of the strengthening phase γ′ (1235°C); (ii) the highest liquidus temperature (heating) obtained by extrapolation was found in the alloy IN713LC (1349°C), the lowest solidus temperature (heating) was found for the alloy IN738LC (1212°C); (iii) At cooling an undercooling occurred in all alloys. In general it may be stated that the biggest under-cooling (TS, 47°C) was recorded in the alloy IN792 5A; (iv) The width of the interval of the heat treatment window was the biggest in alloy IN713LC (44°C); (v) The alloy IN738LC is characterised by the widest interval of melting (124°C) and solidification (134°C), while the alloy IN792 5A has the narrowest interval of melting (82°C) and at the same time almost the same interval of solidification as the alloy IN738LC (129°C); (vi) The obtained phase transformation temperatures were compared with the values of phase transformations temperatures calculated on the basis of established relationships. In order to obtain more precise description of the behaviour of Ni-based superalloys, during controlled heating/cooling of the initial material (as received state) during DTA analyses, all the samples of superalloys were subjected to a phase analysis using scanning electron microscopy. The course of phase transformations, in all the studied superalloys (IN713LC, IN738LC, IN792 5A) is likely to run according to the following reaction scheme (L = melt): L ↔ γ, L ↔ γ + MC, L ↔ γ/γ′, L ↔ γ + minority phases (such as M3B2, phase η), γ ↔ γ′.

Topics: Nickel , Superalloys
Commentary by Dr. Valentin Fuster


2012;():107-115. doi:10.1115/ESDA2012-82064.

Electronic gloves are one of the most common methods used as human hand input devices. They proved to be useful in various applications such virtual reality, sign language interpretation and robotic systems. However, many of these electronic gloves tend to be either economically or computationally expensive. In contrast, this article discusses the development of a data glove that is practical and cost efficient with wireless control capabilities. It is based on placing tri-axial tilt accelerometers on the glove to map the movement of human fingers. All data acquired from the glove is transmitted wirelessly via Bluetooth connection to a computer where it can be used for various applications. The glove was used to control a five-motor tendon driven robotic hand. Tests were carried out to correlate tilt angles acquired from the glove with the appropriate motor values that will move the robotic fingers to the same position as that of the glove fingers. As a result, the robotic hand was able to mimic each human hand finger and thereby perform sign and grasp movements.

Commentary by Dr. Valentin Fuster
2012;():117-125. doi:10.1115/ESDA2012-82084.

S-(nS)PU-SPU and S-(nS)PU-2SPU are two out of three types of under-actuated wrists that are generated from the “ordinary” wrists of type S-3SPU (fully-parallel wrists), by replacing a spherical pair (S) with a nonholonomic spherical pair (nS) according to the rules stated in [1]. Position analysis, controllability, and path planning of these two wrist types have been addressed and solved in two previous papers [2, 3] of this author. Their kinetostatics and singularity analysis have not been addressed, yet; and they are studied in this paper.

Commentary by Dr. Valentin Fuster
2012;():127-136. doi:10.1115/ESDA2012-82103.

Planning smooth trajectories is crucial in the most advanced robotic applications in industrial environments. In this paper two novel trajectory planning methods for robotic manipulators are introduced, named “545” and “5455”. Both methods are based on an interpolation of a sequence of via points using a combination of 4th and 5th order polynomial functions. These techniques allow to obtain a continuous-jerk trajectory for improved smoothness and minimum excitation of vibration. By using the “545” method, null jerk at initial time can be achieved, while with the “5455” method one can impose an arbitrary value of jerk at both the first and the last via-point. The outcome of both methods is the optimal time distribution of the via points, with respect to a predefined objective function. Results are provided for a 3 d.o.f. Cartesian manipulator, but the techniques may be applied to any industrial robot.

Topics: Manipulators
Commentary by Dr. Valentin Fuster
2012;():137-146. doi:10.1115/ESDA2012-82128.

This paper illustrates the activity done by the authors for the development of a hand exoskeleton with two degrees of freedom addressed to the rehabilitation of post-stroke patients. The literature is investigated and many design issues are deeply discussed with the purpose to provide a reader who is approaching this problem with useful guidelines. The feasibility study of a one degree of freedom mechanism for one finger, intended as the basic module of the targeted hand exoskeleton, is outlined: two kinematic chains having six and eight links respectively are presented and discussed.

Commentary by Dr. Valentin Fuster
2012;():147-153. doi:10.1115/ESDA2012-82133.

In order to reach a better productivity in numerous fields, robots have been wildly used for automatic tasks. The main issue of a robot is his lack of adaptability, which is one of the most important ability of human beings. The best tool for adaptability is the human hand. Using pneumatic actuators to drive a robot forearm grants the possibility to move light articles with accuracy and without harming it. It is then necessary to develop accurate model of the different types of actuators. As every human muscle are simulated by those actuators, the size of these must vary and so their properties as well. These artificial muscle-type pneumatic actuators are composed of a rubber balloon, a net, a feeding channel and finally two anchors at both end of the net. Starting with the simplest linear model, we increased the complexity of the model to finally obtain a powerful control of the plastic muscle. To obtain the data we needed for the model, we used a test bench for pneumatic actuators and adjust it to fit the new size of the current actuator. The main difficulty to control the actuator is to find a way to overcome its hysteresis cycle. Then once the model is ready we need to use it to control the different part of the pneumatic forearm. The previous wrist and hand control is enhanced by feed forward control and can perform motion with a great accuracy. The hand can therefore be used without any electronic devices on it and remains lighter and safer. Previous starting dead-zone has been understood and avoided.

Commentary by Dr. Valentin Fuster
2012;():155-164. doi:10.1115/ESDA2012-82168.

In this paper, an effective method in dynamic modeling of spatial flexible-link robots under large displacements and small deformations is discussed and a generic Matlab™ software simulator based on it is presented and validated. The adopted method is based on an Equivalent Rigid Link System (ERLS) that enables to decouple the kinematic equations of the ERLS from the compatibility equations of the displacements at the joints allowing an easy and recursive procedure to build the robot dynamic matrices.

The simulator is suitable for dynamic modelling of generic 3D serial flexible-link robots. The Matlab™ software simulator is validated with respect to the Adams-Flex™ commercial software, which implements Floating Frame of Reference (FFR) formulation, one of the most used methods for dynamic modeling of multibody flexible-link mechanisms with large displacements and small deformations.

Topics: Robots , Design
Commentary by Dr. Valentin Fuster
2012;():165-174. doi:10.1115/ESDA2012-82197.

Currently parallel robots are finding more and more acceptance in high-speed pick-and-place operations. As for all high-speed mechanisms, vibratory phenomena appear and deteriorate accuracy and dynamic performance at the terminal positions of the pick-and-place path. This paper aims to evaluate the effectiveness of several pick-and-place trajectories in terms of vibration reduction. To address this problem, an elastodynamic model of a five bar mechanism is developed and its behaviour is simulated as it traverses each trajectory. Spectral analysis of the vibrations allows the quality of the vibration reduction to be quantified. The results show that the first and second natural frequencies of the system are excited. It is also shown that long cycle times with smooth motion profiles improve residual error norms, but are outperformed by their discontinuous counterparts when short cycle times are imposed.

Commentary by Dr. Valentin Fuster
2012;():175-184. doi:10.1115/ESDA2012-82208.

Serial 3R orthogonal manipulators have been studied recently and it has been proved that they can exhibit good performances in term of workspace size and kinematic properties. The aim of this work is to analyze their dynamic performances, and compare them with anthropomorphic manipulators, which are very popular in industry.

Static and dynamic analyses based on the evaluation of the maximal input torques required for moving the manipulator are achieved. It is shown that, as in kinematics, the dynamic performances of the serial 3R orthogonal manipulators are better.

Topics: Manipulators
Commentary by Dr. Valentin Fuster
2012;():185-194. doi:10.1115/ESDA2012-82213.

The paper focuses on the accuracy improvement of industrial robots by means of elasto-static parameters calibration. It proposes a new optimality criterion for measurement poses selection in calibration of robot stiffness parameters. This criterion is based on the concept of the manipulator test pose that is defined by the user via the joint angles and the external force. The proposed approach essentially differs from the traditional ones and ensures the best compliance error compensation for the test configuration. The advantages of this approach and its suitability for practical applications are illustrated by numerical examples, which deal with calibration of elasto-static parameters of planar manipulator with rigid links and compliant actuated joints.

Commentary by Dr. Valentin Fuster
2012;():195-204. doi:10.1115/ESDA2012-82217.

The paper is devoted to the analysis of robotic manipulator behavior under internal and external loadings. The main contributions are in the area of stability analysis of manipulator configurations corresponding to the loaded static equilibrium. In contrast to other works, in addition to usually studied the end-platform behavior with respect to the disturbance forces, the problem of configuration stability for each kinematic chain is considered. The proposed approach extends the classical notion of the stability for the static equilibrium configuration that is completely defined the properties of the Cartesian stiffness matrix only. The advantages and practical significance of the proposed approach are illustrated by several examples that deal with serial kinematic chains and parallel manipulators. It is shown that under the loading the manipulator workspace may include some specific points that are referred to as elastostatic singularities where the chain configurations become unstable.

Commentary by Dr. Valentin Fuster
2012;():205-210. doi:10.1115/ESDA2012-82218.

Gimbal transmissions are non-linear direct transmissions and can be used in robotic arms replacing the traditional revolute joints. They offer potential advantages for critical cases such as joint space and task space singularities or where a different mechanical advantage is needed compared to what traditional revolute joints provide. This can be obtained by properly adjusting the different parameters of Gimbal joints used in different joints of the manipulator (such as their offset angle and/or chamfer angle). In this paper the concept of Gimbal mechanism as a joint is investigated. Then, as an example, Gimbal joints are used to replace the basic revolute joints of a 3-UPU parallel manipulator and actuator velocities are obtained for a task space trajectory. The outcomes for a manipulator with traditional revolute joints and with Gimbal equipped joints are compared. Then the workspace and dexterity analyses are done on both manipulators.

Commentary by Dr. Valentin Fuster
2012;():211-216. doi:10.1115/ESDA2012-82224.

Based on the Bennett 4R chain, we construct a rotating loop by fixing one R axis to the frame and the fixed R becomes a coaxial double R pair. The R pair opposite to the fixed double R is replaced by a spherical S pair which can be equivalent to a (RRR) open chain with non-coplanar intersecting axes. In the (RRR) sub-chain, we choose special axes and derive R|- R|(R(RRR)R chain moving with 2 DoFs. That moving R becomes a coaxial double R with the addition of another rigid body and the obtained chain with hybrid topology generates a 3-dof motion, which is mathematically modeled by a 3D submanifold of a 4D group of X motions. Because of the product closure in an X-motion group, adding an H pair with any pitch and an axis parallel to the fixed R axis leads to a mechanical generator of a 4D X-motion group. Then, parallel arrangement of two generators of the same X motion gives a new parallel generator of X motion, which can be actuated by four fixed R pairs; the two Hs must have distinct pitches. A special design with four collinear actuated axes is revealed too.

Topics: Linkages , Generators
Commentary by Dr. Valentin Fuster
2012;():217-226. doi:10.1115/ESDA2012-82239.

In this paper, a reduced elasto-dynamic model of the robotic based milling process is presented. In contrast to previous works, it takes into account the interaction between the milling tool and the workpiece that depends on the end-effector position, process parameters and cutting conditions (spindle rotation, feed rate, geometry of the tool, etc.). To reduce the dimension of the problem, the robot dynamics is described as an equivalent mass-spring-damper system with six dimensions. This approach, based on the Rayleigh-Ritz approximation, aims at decreasing computational cost and at avoiding inaccuracy due to ill-conditioning in the full size model. To achieve a realistic modeling of the milling process, the machining efforts due to the interaction between robot, tool and working material are introduced into the robot model and calculated at each time instant. Using this global model that integrates the robot dynamics and the milling process particularities, it is possible to obtain the movement of the robot end-effector and corresponding quality of the final product (profile, macro geometry, etc.). In addition, this model allows selecting the best process parameters and avoiding the vibratory behavior of this machining system which can dramatically affect the milling quality.

The developed model is applied to the behavior analysis of KUKA KR270 robot used for milling applications. This allows finding acceptable range for robot motion profile parameters.

Topics: Robotics , Milling
Commentary by Dr. Valentin Fuster
2012;():227-234. doi:10.1115/ESDA2012-82262.

This paper presents an investigation of the performance of digital hydraulic actuation in robot applications. The research compares two different hydraulic actuation systems, utilizing servo and digital hydraulic valves, developed to drive one leg of a hydraulic quadruped robot (HyQ). Comparisons between the two systems for position tracking, required flow rate and system efficiency are discussed. Results show that digital hydraulic systems can be a valid alternative to servo valves in terms of position tracking, and show that digital valves can greatly improve system performance in the form of reduced required flow rate and improved overall system efficiency.

Topics: Hydraulics , Robots
Commentary by Dr. Valentin Fuster
2012;():235-244. doi:10.1115/ESDA2012-82278.

Giving assistance to surgeons during beating heart procedures is currently a great challenge in medical robotics: a high level of safety is required while the beating heart yields high forces and dynamics. In this article, we investigate the design of an active cardiac stabilizer that will provide a motionless area of interest during the surgery. A device architecture is introduced that is based on planar parallel mechanisms. Such mechanisms are particularly interesting for their manufacturing simplicity and compactness. With the considered architecture, spherical compliant joints based on a planar structure need to be designed. Here we present the use of a 3-RRR spherical parallel mechanism. Its kinematic and stiffness analysis are performed using pseudo-rigid body modeling. An optimization of the mechanism is then achieved, using a modified ant colony optimization technique. The achievable performance of this type of compliant spherical joint is then discussed before concluding on the device adequacy with respect to the surgical requirements.

Commentary by Dr. Valentin Fuster
2012;():245-254. doi:10.1115/ESDA2012-82322.

All over the world, several dozen million people suffer from the effects of post-polio, multiple sclerosis, spinal cord injury, cerebral palsy, etc. and could benefit from the advances in robotic devices for rehabilitation. Thus, for modern society, an important and vital problem of designing systems for rehabilitation of human physical working ability appears. The temporary or permanent loss of human motor functions can be compensated by means of various rehabilitation devices. They can be simple mechanical systems for orthoses, which duplicate the functions of human extremities supplying with rigidity and bearing capacity or more complex mechatronic rehabilitation devices with higher level of control. We attempt to cover all of the major developments in these areas, focusing particularly on the development of the different concepts and their functional characteristics. The robotic devices with several structures are classified, taking into account the actuation systems, the neuromuscular stimulations, and the structural schemes. It is showed that the problems concerning the design of rehabilitation devices are complex and involve many questions in the sphere of biomedicine, mechanics, robot technology, electromechanics and optimal control. This paper provides a design overview of hardware, actuation, sensory, and control systems for most of the devices that have been described in the literature, and it ends with a discussion of the major advances that have been made and should be yet overcome.

Commentary by Dr. Valentin Fuster
2012;():255-264. doi:10.1115/ESDA2012-82363.

In this paper, the stiffness of 3-PPR planar parallel manipulator (PPM) is analyzed with the consideration of nonlinear actuation compliance. The characteristics of the stiffness matrix pertaining to the planar parallel manipulators are analyzed and discussed. Graphic representation of the stiffness characteristics by means of translational and rotational stiffness mapping is developed. The developed method is illustrated with an unsymmetrical 3-PPR PPM, being compared with its structure-symmetrical counterpart.

Commentary by Dr. Valentin Fuster
2012;():265-274. doi:10.1115/ESDA2012-82369.

This paper deals with the shape optimization of a six degree-of-freedom haptic interface device. This six-dof epicyclic-parallel manipulator has all actuators located on the ground. A regular dexterous workspace is introduced to represent the mobility of user’s hand. Throughout this workspace, the deviation of the mobile platform is bounded to provide a better feeling to the user and the masses in motion are minimized to increase the transparency of the haptic device. The stiffness model is written using a virtual joint method and compared with the results obtained with the finite element analysis to be validated. Finally, the shape of the links are optimized in order to minimize the masses in motion while guaranteeing a given stiffness throughout the regular workspace of the mechanism.

Commentary by Dr. Valentin Fuster
2012;():275-281. doi:10.1115/ESDA2012-82384.

Over the past decades, robots have emerged as a valuable technological solution for multiple highly complex industrial processes, and the manufacture of marine propellers has not been an exception. Majority of the propellers being produced worldwide are custom-designed products aiming to satisfy each ship’s propulsion requirements. Such geometrical diversity is a considerable challenge when traditionally manual manufacturing processes like hand-grinding and polishing need to be automated.

In several market-leading propeller manufacturers within Europe and Asia, industrial robots are being applied for widely diverse operations such as milling polystyrene blocks to make moulding patterns, grinding out the excess material in the blade surfaces, or polishing the complete propellers’ surface before their final verification. Propeller blades are customized products, formed by curved and warped surfaces, requiring minimum 5 axes to be smoothly polished, and this can be easily achieved with a robot cell where the CAD/CAM data coming from the individual design are directly translated into robotic parameters.

While this solution has demonstrated to be perfectly capable to comply with the marine propellers finishing tolerances, which are internationally defined by ISO 484 standard rules [6], robotic solutions for propeller measurement have not been successfully implemented within this specific industry due to reasons like lack of accuracy and repeatability. This paper analyses the root causes behind this problem, identifying the calibration process, the cell alignment method and the tool positioning as the principal factors resulting in this low measuring repeatability.

Findings explained by the authors are the outcome of several practical measuring tests made on real marine propellers within ABB and Fanuc robot cells. This paper concludes offering solutions to reduce the inaccuracies caused by the mentioned factors, and recommending what type of marine propellers are more suitable to be measured with industrial robots, on the basis of ISO 484 requirements for each customized design. Moreover, suggestions for further research on this specific measuring application are provided in the concluding chapter.

Topics: Robotics , Propellers
Commentary by Dr. Valentin Fuster
2012;():283-291. doi:10.1115/ESDA2012-82514.

Parallel Kinematic Machines (PKM) are interesting in industrial field because of their ability to ensure high dynamic performance, stiffness, accuracy and precision. One of the parameters used in the design phase of a manipulator relates the opportunity to ensure isotropic performance within the workspace. This paper presents a methodology to graphically identify the points of isotropy of a planar manipulator and defines the geometrical conditions to maximize the number. It is demonstrated that, for some configurations of the manipulator, continuum isotropy loci can be identified. Achieving this goal ensures the efforts related to the design of a manipulator are paid in terms of ability to work, as much as possible, with ideal kinematical conditions.

Commentary by Dr. Valentin Fuster
2012;():293-301. doi:10.1115/ESDA2012-82561.

A walking gait is designed for a planar biped with two identical three-link legs, a trunk and two one-link arms. This nine-link biped is controlled via eight torques to obtain one step of a cyclic gait. The scope of this paper is to investigate the effects of arms swing on the energy consumption during walking of a fully actuated planar biped robot. Kinematics and dynamics of a biped, HYDROID, are used for this study. Desired gaits are considered to be cyclic having single support phases separated by flat foot impacts. Different evolutions of the arms: arms held, arms bound and arms swing are compared. For each case, we use a parametric optimization method with constraints to produce reference cyclic trajectories according to an energy criterion. The numerical results show that this criterion is lower in the case where the arms swing.

Commentary by Dr. Valentin Fuster
2012;():303-309. doi:10.1115/ESDA2012-82564.

Research on running robots has generally focussed on the steady-state. When the ground has limited foot placement surfaces or there are sudden changes in height then steady-state running is not possible. It becomes necessary to make step-by-step adjustments to place the foot.

In this paper a mass-spring-damper model of a robot’s leg is used to develop a hopping controller capable of meeting rapid changes in demand height or flight time. Analysis of the model provides a simple method to select control parameters for effective height control without tuning or iteration. Additionally, a simple adaptive algorithm is introduced and demonstrated in simulation. The adaptive control algorithm allows rapid changes of height even when ground characteristics change. Experimental validation is ongoing and some preliminary results are provided.

Topics: Robots
Commentary by Dr. Valentin Fuster
2012;():311-320. doi:10.1115/ESDA2012-82580.

The design of a knee joint is a key issue in robotics and biomechanics to improve the compatibility between prosthesis and human movements and to improve the bipedal robot performances. We propose a novel design for the knee joint of a planar bipedal robot, based on a four-bar linkage. The dynamic model of the planar bipedal robot is calculated. We design walking reference trajectories with double support phases, single supports with a flat contact of the foot in the ground and single support phases with rotation of the foot around the toe. During the double support phase, both feet rotate. This phase is ended by an impact on the ground of the toe of one foot, the other foot taking off. The single support phase is ended by an impact of the swing foot heel, the other foot keeping contact with the ground through its toe. For both gaits, the reference trajectories of the rotational joints are prescribed by polynomial functions in time. A parametric optimization problem is presented for the determination of the parameters corresponding to the optimal cyclic walking gaits. The main contribution of this paper is the design of a dynamical stable walking gait with double support phases with feet rotation, impacts and single support phases for this novel bipedal robot.

Commentary by Dr. Valentin Fuster
2012;():321-327. doi:10.1115/ESDA2012-82606.

Cadaveric experiments and computer simulations have shown that the tendon network of the fingers performs logic computation to preferentially change torque production capabilities. Distribution of input tensions in the tendon network itself regulates how tensions propagate to the finger joints, acting like the switching function of a logic gate. The tendon network as proposed by Winslow (1669–1760) is responsible for this phenomenon; and that a certain switching behavior is exhibited, depending upon the input tension loading. This work explores how this switching behavior varies with different static postures of the finger and under different loading conditions on input tendon terminals. Experimental setup is designed and developed to study this switching behavior, comprising of a bio-mimetic model of middle finger, designed and developed. Winslow’s tendon network as proposed by Winslow is employed over it. Force sensors based on strain gauges are designed and developed in order to measure the tension at the proximal and terminal slips of network. Experiments have been carried out to understand the switching behavior exhibited by rhomboidal tendon network and how it varies under different loading conditions. Its variation with different pre-configured postures under static equilibrium is observed. Results show that indeed the rhomboidal tendon network of Winslow exhibits switching behavior and that they vary under different loads and postures of the finger.

Topics: Tension
Commentary by Dr. Valentin Fuster
2012;():329-334. doi:10.1115/ESDA2012-82636.

In this paper, the performance of compliant parallel manipulators, in a given working position, is evaluated in terms of the MA (mechanical advantage) and k(J) (kinematic condition number). Such evaluation is done by means of a new and fast method for direct kinematic analysis of parallel manipulators. The method, which is useful to enhance both the design synthesis and the control strategy, is applied on the so called pseudo-rigid body mechanism, which represents a simplification of its corresponding compliant mechanism. Computer codes have been developed in MatLab programming language. The case under study consists of a MEMS (Micro Electro Mechanical System) compliant robot that has been built by the research group in silicon for micromanipulation. Such MEMS robot could be designed thanks to a new flexural hinge concept. Some experimental tests have been carried out on sample prototypes in order to inquire about the real feasibility of the micro-robot.

Commentary by Dr. Valentin Fuster
2012;():335-342. doi:10.1115/ESDA2012-82681.

Due to the bulk and stiffness of the astronauts’ glove, so called Extravehicular Activity (EVA) glove, many problems occur during their missions outside the spacecraft i.e. fatigue, dexterity reduction, decrease of possible EVA hours, etc. [1, 2]. To solve these problems a hand exoskeleton which can be embedded inside the astronauts’ glove has been proposed as a solution to help them to move their fingers more easily.

In this work all the steps that were taken towards the design of a preliminary version of the hand exoskeleton are explained in detail. The paper starts with a brief survey on related literature, followed by an analysis of three main research subjects for the design and realization of the hand exoskeleton: sensors, actuators and structure. In particular, different kinds of sensors and actuators are evaluated and advantages and disadvantages of each one are investigated. Then the main reasons to choose a specific type of sensor or actuator are described in detail. Regarding the structure, different possible solutions converging towards an optimal design for this application have been evaluated. Moreover, the use of some springs in the structure to simulate the stiffness of the EVA glove is proposed in order to be able to test the device in a condition similar to its final application. A brief description about the kinematic modeling and simulation of the structure in order to find the optimum location of the transmission cables and their tension forces is explained.

Topics: Design
Commentary by Dr. Valentin Fuster
2012;():343-352. doi:10.1115/ESDA2012-82744.

This paper introduces the research carried out on the design of a robotized teleechography system. Such a system is composed of a master control device and a slave robotic manipulator. Our objective is to contribute to the French Agence National de Recherche (ANR) project PROSIT by designing both devices. To define the kinematic architecture, we had proposed an approach based on the analysis of the expert gesture as a first step of the design process. We have used a motion capture system to study the ultrasound examination gesture and to define the kinematic specifications for the proposed manipulator. A new kind of architecture was selected: the spherical parallel mechanism (SPM). We have chosen it because it reaches the constraint requirements. The kinematic architecture was synthesized by executing a real-coded genetic algorithm (GA). We integrated optimization criteria in the synthesis of the selected architecture. We have fixed a minimum required workspace and we have chosen to optimized the SPM in terms of dexterity and compacity. Another important part of our research was to design a haptic device to provide a very intuitive control of the tele-operated robot. We have opted for a free hand interface that integrates an active force control and feedback. An Inertial Measurement Unit (IMU) has been integrated. The data collected from the IMU that we integrated are processed by a Kalman Filter. But we have modified this predictor-estimator tool from the state of art to adapt its behavior with respect to the type of motion done by the operator. Experimentations via our motion capture system have demonstrated the accuracy of this orientation control strategy. The final step will be the experimental and clinical validation on real patients.

Topics: Design , Optimization
Commentary by Dr. Valentin Fuster
2012;():353-359. doi:10.1115/ESDA2012-82883.

Experimentation is a very important part of education in engineering including mechatronics engineering, which is a relatively new field, combining three engineering disciplines: mechanical engineering, electrical engineering and software engineering. The equipments needed for experiments in mechatronics are usually expensive. A solution to make these expensive equipments achievable is to share them with other universities or research centers from different locations in the world.

The goal of our team is to build a networked telerobot system so that the Internet users, especially researchers and students, can be able to control an autonomous robot able to explore a dynamic environment remotely from their home and share the robot system with the department. The particularity of the environment, in this case, is that the experiment uses grid lines painted on the floor, for robot navigation purpose.

The system which is still under development will be able to increase the number of robots. The communication software technologies are based on PHP. A specific protocol over IP was designed for communication between the server and clients.

The aim of this project is oriented toward providing a telerobot system with a high degree of local intelligence in order to overcome restricted bandwidth and transmission delay of the network.

Topics: Design , Internet
Commentary by Dr. Valentin Fuster
2012;():361-370. doi:10.1115/ESDA2012-82903.

Imitation learning is one of the forms of social learning that enables the human or robot agents to learn new skills. The knowledge acquired for imitation can be basically represented as action mapping based on “organ matching” which determines the correspondence between imitator and imitatee, if the imitator and the demonstrator share the same embodiment. In this paper, we aim at imitation of two system with totally different dynamics, imitating each other, where any correspondence is missing. Towards this aim, we adopt a case where the imitator is a fluidic system which dynamics is totally different than the imitatee, that is a human performing different body poses. Our work proposes the fluidics formation control of fluid particles where the formation results from the imitation of observed human body poses. Fluidic formation control layer is responsible of assigning the correct fluid parameters to the swarm formation layer according to the body poses adopted by the human performer. The movement of the fluid particles is modeled using the Smoothed Particle Hydrodynamics (SPH) which is a particle based Lagrangian method for simulation of fluid flows. The region based controller first extract the human body parts generating the regions where the attention is attracted by the imitatee and fits an appropriate ellipses to delimite boundaries of those regions. The ellipse parameters such as center of the ellipses, eccentricity, length of the major and minor axis etc. are used by the fludic layer in order to generate human body poses. This paper introduces our technique and demonstrates the imitation performance of our system.

Commentary by Dr. Valentin Fuster
2012;():371-379. doi:10.1115/ESDA2012-82978.

In this work a method is proposed for modeling and simulation of multibody mechanical systems with multiple lubricated revolute joints with the aid of CAD and dynamic simulators softwares. The hydrodynamic forces produced between joint components due to lubrication are obtained by integrating Reynolds’ equation that is used for evaluating the fluid pressure distribution in the journal–bearing joint. The resulted force equations are combined with Hertz contact model to make a complete model for lubricated revolute joints. This model is used with the aid of SolidWorks/CosmosMotion software package to simulate multibody systems with multiple lubricated revolute joints and a computational algorism is developed in the frame of multibody dynamics methodology. A slider–crank mechanism with two lubricated revolute joints is used as an application example to demonstrate the efficiency and versatility of the proposed method. The simulation results point out that the introduction of a lubricant at the joint clearance makes the performance of the mechanism so close to that of the ideal mechanism that does not suffer from the clearance problem, as well as improves the overall system performance.

Commentary by Dr. Valentin Fuster
2012;():381-391. doi:10.1115/ESDA2012-83001.

The functional work space for a given orientation is a subset of the work envelope and is not intuitive to define for 6 axis industrial robots. A 2D boundary curve is derived for each desired end effector orientation and tool vector. This is done via a geometric analysis and using the Denavit-Hartenberg notation for the forward kinematic representation. The feasible region for all orientations is determined by the use of Boolean intersections. Disjoint regions may occur. Assessing these elements establishes the boundary limits for subsequent evaluation and optimization tasks. An ABB IRB 140 robot is used to highlight the methodology.

Topics: Kinematics , Robots , Shapes
Commentary by Dr. Valentin Fuster
2012;():393-397. doi:10.1115/ESDA2012-83012.

The Automated Sailing Robots (ASR) concept is receiving an increasing interest among robotic researchers. Most oceanographic in situ surface measurements are currently performed via fixed buoys or passive drifting buoys. By taking advantage of the wind power an ASR will be able to conduct very long term offshore data gathering missions in virtually any place of the oceans. In this paper we describe an original prototype developed at ISAE: design, embedded systems, simulation model, performance are detailed. We eventually address the challenging problem of middle level closed loop control: rudder and sail control for course keeping. An original sail control strategy is proposed that both combine high performance and low energy consumption. The paper concludes with simulation and experimental results.

Topics: Robots
Commentary by Dr. Valentin Fuster

Information Management and PLM

2012;():399-408. doi:10.1115/ESDA2012-82201.

This paper presents a formalization of the complementary information structures approach, which was originally derived from the practical implementation of a Manufacturing Process Management solution. The Environment-based Design methodology has been chosen to generalize the Manufacturing Process Management experience and the resulting theoretical foundations are then used to propose a complementary information framework between customer needs and product descriptions. The definition of the relationships between the structures is derived from the “customer job mapping” approach used in Outcome Driven Innovation marketing techniques.

Commentary by Dr. Valentin Fuster
2012;():409-416. doi:10.1115/ESDA2012-82391.

Successfully fulfilling customers’ needs with world class products whilst remaining competitive and profitable are a major driver for the aerospace industry. The 21st Century is placing ever increasing pressure upon manufacturers to deliver high complexity, technologically enabled products to instantaneously fulfill a desired purpose at the point of use. To meet such stringent criteria, companies must find ways to continuously improve, reduce waste and accelerate the product development process whilst innovating.

This paper presents a multiple case study approach of turbine blade manufacturing part families which has been used to further develop a manufacturing knowledge reuse method that is being developed in partnership with a high tech aerospace company for application within a PLM environment. This method is currently being explored within the company so as to accelerate the design-make process to enable earlier availability of, and easier access to, manufacturing knowledge, thus bringing about better product performance.

The contents of the paper presents a methodical approach to the study of a number of products in an effort to ascertain how the complex interrelationships between design knowledge and manufacturing knowledge change across part families and, consequently, how they affect a developed feature knowledge relationship structure (FKRS) that maps design, manufacture and inspection viewpoints of product knowledge. Utilizing the FKRS, a pragmatic way has been developed in which people-to-people knowledge can be captured and shared to facilitate a reduction in the associated lead-time for information and knowledge retrieval and reuse. For this to be more widely applicable to different types of turbine blade it is necessary to widen the scope of the research. Four case studies are presented showing the aspects that constitute a part family and how knowledge varies across the products being studied. The FKRS is applied to the captured manufacturing knowledge in an effort to prove that it can represent and model multi-context knowledge across part families.

The results have shown that the approach provides a basis for the representation of complex relationship viewpoints for product features and is valid for a number of manufacturing part families.

Topics: Manufacturing
Commentary by Dr. Valentin Fuster
2012;():417-424. doi:10.1115/ESDA2012-82414.

In recent years, energy consumption issues, boosted by environmental concerns, are becoming of paramount importance in the manufacturing field. In particular, machinery sector has been the theatre of several initiatives and projects aimed at an eco-efficient design and use of the machines. In this context, energy consumption modeling is considered a powerfull tool to foresee and optimize energy efficiency by design. On the other side, while each company has to develop numerical models of the internally designed machine elements, it has to be taken into account that machine productivity, eco-performance and cost are all strongly influenced by the employed commercial components (e.g. motors, sensors, controllers, transmissions, guide ways), that must be also be modeled but it is unrealistic to expect that the machinery builder develops by himself all required models.

In this paper, the industrial adoption of simulation tools and methodologies for energy consumption modeling is regarded as an application of the more general “Model Based Product Development” methodology. In particular, the development of “functional component models”, seen as Virtual Components (“VC”) to be assembled in the Virtual Machine, is suggested as the key to foster co-modeling activity involving suppliers. A proper business model is then proposed to guarantee the sustainability of the co-operation scenario.

Finally, the strategy concept is illustrated by some examples concerned with machine tool accessories and components.

Commentary by Dr. Valentin Fuster
2012;():425-434. doi:10.1115/ESDA2012-82426.

Cross-company collaboration in product development is currently faced with major challenges because of varieties of reasons. Companies depend on acquiring the know-how for innovative future products from outside the company while the support is not limited on the product development but rather on continuous collaboration over product life cycle and consequently are planned for long term normally. These development partners have to get an early and deep read into product and process design of the company for a goal-oriented cooperation. Despite these far-reaching knowledge of the development partner about the own company, the selection of a development partners is still founded on subjective criteria or random acquaintances yet. This approach uses data from ERP systems for the business view and of PDM systems representing the technical view for the monitoring of current cooperation and development partners. It becomes possible to monitor actual collaborations continuously and targeted for their suitability and also serves to gather and analyze information in order to select suitable development partners.

Topics: Collaboration
Commentary by Dr. Valentin Fuster
2012;():435-442. doi:10.1115/ESDA2012-82703.

Product data translation is essential for the seamless integration of various product-centric activities. Yet, the process to build translators among different software has been left mostly to individual expertise rather than a formal procedure. In this paper, we propose a framework to automatically determine translation rules to enable translation of instances from one system to another. We use a graph search method to obtain the overall translation rule as a combination of multiple basic functions. We apply this method to a subset of non-geometric product knowledge, such as date of creation, color and name of feature used in two commercial systems. We detect the rules using a manually created training data set and evaluate their correctness manually.

Commentary by Dr. Valentin Fuster
2012;():443-452. doi:10.1115/ESDA2012-82784.

The software tools for PLM and project management are often built around several classical concepts: Processes, Activities, Phases, Artefacts, Workflows, Resources and Relationships. This approach does not really consider the team concept and the particular dynamics of the project management. This leads to a paradox with PLM and project management software tools. They tend to reduce risk and improve performance by structuring, streamlining, automating and scheduling projects without considering projects are not well-structured and have their own dynamic. The negation of project management mode increases the risks of project failures, adds stress to team members and requires the addition of complex mechanisms of collaboration and delegation. PLM Software sometimes becomes a limitation for project management. Our partner, LASCOM, a French PLM software developer, decided to make evolve its solutions to provide customers more efficient PLM solutions. LASCOM initiated a reflection around new concepts for enrich its existing models and tools since few years. The company particularly has an interest on the practical use of the concepts of roles and contexts. This paper deals with the addition of these concepts in the models used by LASCOM. This addition is intended to partially solve the problems posed by the generalization of work by project in organizations.

Commentary by Dr. Valentin Fuster
2012;():453-464. doi:10.1115/ESDA2012-82791.

An emerging trend in defence and aerospace is the move from manufacturing and selling products to providing the availability of a product-related function based on long term contractual agreements between the customer and the service provider. Therefore the concern of the manufacturer as a service provider shifts towards all means that are required to ensure the availability of the product related function. This ultimately imposes the adoption of a broader perspective on a complex system of interconnected and interdependent activities undertaken by a diverse network of stakeholders for the achievement of a common purpose. Nonetheless, a consistent and comprehensive way to represent such complex systems is not yet agreed upon in the literature. For the purpose of estimating the costs of a Product Service System (PSS) delivery, a consistent and common representation of products and services is a necessary precondition.

The focus of this paper is to contribute to the debate by proposing the use of knowledge as the underlying foundation for representing products, services and PSS.

Building upon inter-disciplinary literature, differing concepts of PSS are discussed, in order to identify recurring aspects and commonalities between product and service. While it could be recognised that technology represents such a common element, it is also recognised that differing definitions of technology do not facilitate the discussion about product, service, and PSS. Instead, evidence is found for the argument that applied knowledge can be seen as the underlying foundation for products, service and PSS. In this sense, knowledge is not considered as a single asset, but rather a composition of different kinds of knowledge.

The authors propose the application of knowledge to a process-based approach, which facilitates the representation of products and services by overcoming their distinction in a consistent way. While the composition of knowledge related to each process is a necessary precondition to enable the successful delivery of a PSS, it furthermore requires knowledge about integration of all process inputs, outputs and the processes’ dynamics within a given environment. Herewith the focus shifts to the preconditions that enable the successful delivery of a PSS, such as available set of skills and underlying process understanding.

Discussing the role knowledge plays in current cost estimation methods it is found that — despite its importance — knowledge is not always clearly defined, and very often it is reduced to repository-based data retrieval systems.

The proposed knowledge-based process-orientated approach aims to facilitate investigating products, services, PSS, and the underlying production and delivery systems by representing them in a transparent and consistent way. While this is generally not bound to a particular type of analysis, the motivation originates from estimating the costs of a PSS delivery.

Commentary by Dr. Valentin Fuster
2012;():465-471. doi:10.1115/ESDA2012-82830.

In this article we propose a new way for enriching technical models that drive contemporary enterprise. Our proposition is to take into account a new stage in the object lifecycle: at its end, it enters into a new phase that we call “heritage lifecycle”. Indeed, many old technical objects fall in ruins and are destroyed after their uses. After capitalization, we propose to conserve them virtually. Thanks to virtual tools coupled to database, it will help us to define a new information system for driving the long life cycle of objects: it is the Digital Heritage Reference Model, DHRM. This information system will be implemented in a new PLM dedicated to museum, place where know-how and mankind’s knowledge is stored and promoted when possible. Museum-related PLM would eventually interact with enterprises PLM as a bijective enrichment.

Topics: Cycles , Databases
Commentary by Dr. Valentin Fuster
2012;():473-482. doi:10.1115/ESDA2012-82860.

Companies can use methodological software tools to perform requirement engineering. Those methodological tools are increasingly developped by external software editors and integrators. The performance of the tools is not enough to ensure efficiency of methodology application.

This paper is part of a PhD research programm. This research program focuses on the way of integrating requirement engineering tools into product design department with a provider perspective. To be more precise, this research project emphasizes on modifications occuring during integration phases. In order to evaluate and to improve integration process, key indicators can be proposed. From the first stage of integration to the moment the user is autonomous, key integration factors often change. For example, requirements of the user, user environment, product life cycle, delay for integration, actors, … This paper aims at proposing surveys to identify those changing key factors. Then, first best practices elements are given to counteract the possible negative impact on efficiency of requirement engineering tools integration and thus, on product development. In fact, this paper goes further into the way to analyze the existing system. It notably deals with first elements from industrial survey on IT vendor and their customer perspectives on tools integration. In addition, preliminary survey results on customer dissatisfaction are proposed and analyzed. It also proposes a short case study and further research work in order to assume those first results and to bring to the definition of integration approach for methodological tools in engineering domain.

Commentary by Dr. Valentin Fuster
2012;():483-489. doi:10.1115/ESDA2012-82914.

Today, within the global Product Lifecycle Management (PLM) approach, success of design, industrialization and production activities depends on the ability to improve interaction between information systems that handle such activities. Enterprises deploy mainly PLM system, Enterprise Resource Planning system (ERP) and Manufacturing Execution System (MES) in order to manage sufficient product-related information and provide better customer-products. This paper proposes a methodological approach to improve the quality of data exchanged between engineering and production. This involves the integration among information systems especially the PLM-MES integration. Thus, the proposed approach aims to overcome the problem of data heterogeneity by proposing a mediation system resolving syntactic and semantic conflicts of data managed by these systems.

Commentary by Dr. Valentin Fuster
2012;():491-502. doi:10.1115/ESDA2012-82934.

The paper describes an approach to product relationships management in the context of concurrent engineering and product lifecycle management (PLM). Current industrial practices in Product Data Management and Manufacturing Process Management systems require better efficiency, flexibility, and sensitivity in managing product information at various levels of abstraction throughout its lifecycle. The aim of the proposed work is to manage vital yet complex and inherent product relationship information to enable concurrent product design and assembly sequence planning. Indeed, the definition of the product with its assembly sequence requires the management and the understanding of the numerous product relationships, ensuring consistency between the product and its components. This main objective stresses the relational design paradigm by focusing on product relationships along its lifecycle. This paper gives the detailed description of the background and models which highlight the need for a more efficient PLM approach; then the theoretical approach is described.

Commentary by Dr. Valentin Fuster
2012;():503-512. doi:10.1115/ESDA2012-82935.

This paper aims at presenting an approach to structuring interactions within product, through a graph, for simulation purposes. This approach has been developed for specific needs on Simulation Lifecycle Management (SLM) dedicated to aircraft engine development. The paper also illustrates the implementation of this approach on a case study which concerns a compressor design.

Commentary by Dr. Valentin Fuster
2012;():513-520. doi:10.1115/ESDA2012-82941.

Industrial companies are confronted to reverse engineering on mechanical components. They have to define a new process planning from 3D information (points cloud, drawings, etc.). The component has to be re-engineered in order to improve and optimize new manufacturing processes. According to surveys, reverse engineering approaches begin to be supported by Knowledge Base engineering Systems (KBS). These systems are efficient to quickly obtain CAD models based on functional features. These models are successful for redesigning activities and then for defining a process planning. Industrial companies often need to re-engineered components in order to define directly a new process planning. In this case CAD models, based on functional features, are not useful. This paper suggests an approach called Reverse Engineering For Manufacturing (REFM) which allows to directly obtain a CAPP (Computer Aided Process Planning) model from 3D information. The system management is based on Design For Manufacturing (DFM) approach and enables to manage manufacturing information (such as the number of fixtures, the kind of milling operations, etc.). In addition, this system management allows to define process planning alternatives. The aim of the paper is to show the concept of REFM approach according to a use case.

Commentary by Dr. Valentin Fuster
2012;():521-533. doi:10.1115/ESDA2012-82943.

In the last two decades during which the competitive business environment increased, it became crucial for each company to find the most accurate strategy to make survive its business. For that reason they need to manage and control their costs. Life Cycle Costing is one of these tools, which helps to analyse the cost of a product in the whole life of a product. To be competitive, the organisations have to optimize not only their products but also all their processes. Manufacturing Process Management (MPM) addresses the area between product design and production. Therefore MPM supports to optimize the manufacturing area of a factory. With different virtual scenarios the best solution of the manufacturing process can be obtained and at the same time it is possible to reduce time to market, costs and increase the quality. The focus of this paper is to integrate Life Cycle Costing tools and methods in the MPM part of the Product Lifecycle Management (PLM). We will discuss the implementation of Activity Based Costing (ABC) and Case-Based Reasoning (CBR) methods in a PLM tool for an early design decision support.

Commentary by Dr. Valentin Fuster
2012;():535-540. doi:10.1115/ESDA2012-82945.

Configuration management of modular mechatronics products is an effective way of rapid development for the modular mechatronics industry. By summarizing the relevant literature, the concept of product configuration is illustrated. Then this article sums up the latest research progress for configuration design process modeling, configuration knowledge management, implementation method for configuration management methods. Finally, the weak aspects of present research are discussed, and the following research topics are determined.

Topics: Mechatronics
Commentary by Dr. Valentin Fuster

Design Engineering

2012;():541-550. doi:10.1115/ESDA2012-82099.

For Multi-Objective Robust Optimization Problem (MOROP), it is important to obtain design solutions that are both optimal and robust. To find these solutions, usually, the designer need to set a threshold of the variation of Performance Functions (PFs) before optimization, or add the effects of uncertainties on the original PFs to generate a new Pareto robust front. In this paper, we divide a MOROP into two Multi-Objective Optimization Problems (MOOPs). One is the original MOOP, another one is that we take the Robustness Functions (RFs), robust counterparts of the original PFs, as optimization objectives. After solving these two MOOPs separately, two sets of solutions come out, namely the Pareto Performance Solutions (PP) and the Pareto Robustness Solutions (PR). Make a further development on these two sets, we can get two types of solutions, namely the Pareto Robustness Solutions among the Pareto Performance Solutions (PR(PP)), and the Pareto Performance Solutions among the Pareto Robustness Solutions (PP(PR)). Further more, the intersection of PR(PP) and PP(PR) can represent the intersection of PR and PP well. Then the designer can choose good solutions by comparing the results of PR(PP) and PP(PR). Thanks to this method, we can find out the optimal and robust solutions without setting the threshold of the variation of PFs nor losing the initial Pareto front. Finally, an illustrative example highlights the contributions of the paper.

Commentary by Dr. Valentin Fuster
2012;():551-560. doi:10.1115/ESDA2012-82106.

In order to decrease both energy consumption and CO2 emissions, the automotive, aeronautics and aerospace industries aim at making lighter vehicles. To achieve this, composite materials provide good opportunities, ensuring high material properties and free definition of geometry. As an example, for cold applications, the use of carbon fiber/thermoset composites is ever increasing, in spite of a high fiber price. But in a global and eco-friendly approach, the major limitation for their use remains their potential recyclability. Recycling a composite means having a recycling technology available, getting a dismantle solution and an access for the product, and disposing identification plus selection possibilities to the materials. Thus, carbon fibers recovery (i.e. recycling and re-processing) would both help design engineers to balance energy efficiency and cost, and open new opportunities for developing second-life composites, dedicated to the manufacture of medium or low loaded parts (non-structural in many cases).

A first section presents an overview of composite recycling possibilities. Indeed, environmentally and economically, composite incineration is not attractive (even with an energetic valorization), let-alone burying. Reuse and recycling thus remain the two most interesting options.

Aeronautics offers a high potential in terms of fiber deposit. In southwest France, composites recycling will increase in terms of quantity due to dismantling platforms Tarmac (dedicated to civil aircraft applications) and P2P (for the disassembly of ballistic weapons). In addition, from a technical point of view, and even if end-of-life solutions for composites still remain under development, solvolysis (i.e. water under supercritical conditions) already offers the opportunity to recover carbon fibers. The resulting recyclate retains up to 90 percent of the fiber’s mechanical properties.

A second part will explore the recycling to design issue (i.e. how recycling processes have to balance the previous aspects of the end-of-life proposal).

The recycler clearly becomes a new supplier in the carbon fiber lifecycle, by revalorizing wastes with alternatives to burning. Moreover, increasing carbon fiber shelf life reduces its product life impact. Finally, promoting carbon fiber end-of-life would ensure to link aeronautics, automotive, and leisure and sports industries; but one can create demand for recycled reinforcement, by packaging it in useful and attractive forms for those end-users (e.g. pseudo-continuous fiber, felt, strips, bands, patches, etc.).

These sections will be enlightened by several examples from collaborations between I2M and local industries.

Commentary by Dr. Valentin Fuster
2012;():561-566. doi:10.1115/ESDA2012-82131.

This study proposes a design of transmission mechanism which is referred to as a series-type independently controllable transmission (ICT). The series-type ICT is an alternative form of the parallel-types proposed in the former researches. The series-type ICT can serve as a continuously or an infinitely variable transmission mechanism, and it can also produce a required angular output velocity that can be independently manipulated by a controller and not affected by the angular velocity of the input shaft. The series-type ICT mechanism is composed of two planetary gear trains and two transmission-connecting members. Kinematic and dynamic characteristics of the ICT mechanism are analyzed and their analytical equations are derived for application in this study.

Topics: Design
Commentary by Dr. Valentin Fuster
2012;():567-576. doi:10.1115/ESDA2012-82204.

The need for geometrical variations management is an important issue in design, manufacturing and all other phases of product development. Two main axioms cover geometrical variations, namely the axiom of manufacturing imprecision and the axiom of measurement uncertainty. Therefore, this paper reviews common models for the description of non-ideal geometry (shape with geometric deviations) and shows how the random field theory can be applied to create more realistic skin models (a model which comprises these geometric deviations).

Furthermore, methods to estimate and to express the underlying random field from a sample population are shown. These can be used to create and simulate random shapes considering systematic and random deviations observed through measurement or gathered from manufacturing process simulations.

The proposed approach incorporates given information from manufacturing process simulations or prototypes. Based on these information, skin model samples are created which can represent the “realistic” part in assembly simulations or other geometrical analyses. This can help to identify the optimal tolerance sets within every stage of the product development process. The efficiency of the introduced approaches is shown in a case study.

Topics: Simulation , Skin
Commentary by Dr. Valentin Fuster
2012;():577-589. doi:10.1115/ESDA2012-82206.

There have been various attempts to deal with the optimization of solutions which involve expansion joints in piping systems where sufficient flexibility can’t be found using suitable pipe routing.

The difficulty of piping designs which involve expansion joints is that they rely upon two engineering expertises: Pipe Flexibility and Stress Analysis on one side and Expansion Joint Design and Construction on the other. Arguably distinctively different, they have been looked upon as totally detached engineering disciplines and it is rarely that companies have two of these experts residing under the same roof. Pipe Stress Engineers basically relied on support form Expansion Joint Experts on “as required basis” and called upon their knowledge only when needed. Thus, we have the situation where knowledge related to the design and construction of expansion joints sits with expansion joints manufacturing companies, which are totally separate and often remote entities in the piping design process.

Even so, the ever present demand for techno-economical optimizations, points us to the following observations.

The “Traditional method”, where Pipe Stress Engineer defines on his own the requirements for expansion joints and describes them in the technical specification for purchasing is, or should be, a theme of the past.

This approach may be used only as a first attempt in search for the solution, but given that it never heads in the direction of achieving optimal techno-economical results, needs to be upgraded with additional steps.

Commentary by Dr. Valentin Fuster
2012;():591-595. doi:10.1115/ESDA2012-82245.

Efficient belts can provide the same magnitude of energy savings as energy-efficient motors. Therefore, belt drives deserve greater attention, so that their losses should be minimized. The belt drive power losses are a combination of torque losses and speed losses. However, the determination of belt drive behavior in terms of power losses requires extensive experimental investigations. Therefore, in this study, belt slip and torque losses were investigated experimentally with a laboratory constructed test bench. Measurement System Analysis (MSA) was performed in order to investigate the test rig reliability. Special attention was paid for experimental test setup, testing and modeling of torque loss behavior of V-ribbed belt drive systems. Significant design parameters were investigated.

Topics: Torque , Belts
Commentary by Dr. Valentin Fuster
2012;():597-606. doi:10.1115/ESDA2012-82259.

Product design is now driven to the satisfaction of requirements all along the life cycle of the product, with an increased concern in environmental impact. A new concept, the Green-Use (GU) Learning Cycles, is proposed. It is used to determine the way a continuous, adaptive interaction between user and product can be established to improve environmental performance during use. It is structured by two levels of analysis (macro and micro) and a cyclic nature. These levels are the “Incremental user involvement levels”, and the “Environmental Impact in Use”. They are modelled around the notion of an evolution in cycles, from the initial state of the system product-user to a final stage which results in optimal use with minimal environmental impact. This work includes experimentation to support the new concept proposed, as well a method to use it.

Commentary by Dr. Valentin Fuster
2012;():607-613. doi:10.1115/ESDA2012-82274.

The chatter of motorcycles is a self-excited vibration that may appear during braking. This vibration can be very strong and the accelerations of both the rear and front unsprung masses can reach 5–10g with frequencies in the range 17–22Hz, seriously hindering the rider’s control of the vehicle. Very few studies exist on this topic, and the first work that compares experimental data to numerical simulation and addresses the fundamental mechanisms of the chatter genesis has been recently published. In the current paper authors present the continuation of the research, and in particular the results of a parametric analysis performed to identify the most important design and motion parameters when it comes to chatter stability. The analysis is carried out by simulating chatter with a validated nonlinear motorcycle multibody model which captures the most important vehicle features.

Topics: Chatter , Motorcycles
Commentary by Dr. Valentin Fuster
2012;():615-623. doi:10.1115/ESDA2012-82290.

Computer-aided engineering is widely used in various areas including manufacturing, requirement planning and product design. These specific CAE tools, here called expert tools, manipulate large amounts of data. Some of those data also need to be processed by other expert tools to allow a flexible collaboration between various experts. This article proposes an approach to exchange data of various formats manipulated by different expert tools through model-based technologies. The presented approach is validated by its implementation on an academic use case involving commercial industrial tools.

Commentary by Dr. Valentin Fuster
2012;():625-636. doi:10.1115/ESDA2012-82317.

This paper deals with design and manufacturing of a mechanical variable valve actuation (VVA) system, developed as part of a MUR financed research project concerning the realization of a high performance motorcycle engine, through a partnership of Moto Morini (Bologna), Dell’Orto (Milano), Istituto Motori - CNR (Napoli) and DiME (Department of Mechanical Engineering and Energetics) – University of Napoli Federico II.

After a synthetic description of the main variable valve actuation methods currently employed, the paper presents the results of our mechanical VVA system, consisting of three main elements: cam, main rocker arm with fixed fulcrum and secondary rocker arm with mobile fulcrum. This VVA system (system 1) enables valve lift variation by a simple translation of one of the three elements (the intermediate one). The study has been conducted implementing a numerical procedure specifically designed to determine cam profile and kinematic and dynamic characteristics of the whole system, starting from the following input data: rocker arm geometry, relative positions and inertial data of elements, spring stiffness and preloading, camshaft speed and valve lift law. The model has been validated against the conventional timing system using kinematic simulations. Results of the numerical procedure verify the validity of the VVA system, capable of a valve lift variation, with a limited acceleration. Starting from the numerical results, we have developed a new mechanical variable valve actuation system (system 2): it consists of the same three elements used previously, but they are connected in a different way. The newer system enables more general lift profile distributions with a similar geometric complexity. The activity has been extended to research for a new solution (always a mechanical system), capable to allow inlet valves complete closing and timing and duration variation (system 3).

This paper reports results reachable with the simplest system 1, that gives better perspectives of use for a new two-wheel vehicle engine.

Commentary by Dr. Valentin Fuster
2012;():637-646. doi:10.1115/ESDA2012-82321.

This paper lies within the integration of an eco-design method adapted to the Innovation structure at a car manufacturer. The environmental constraints in the automotive industry are more and more important (European emission standards for exhaust emissions, European directive on end-of life vehicles …). Eco-design is a new manner to design products related to the concept of sustainable development, which combines economy and ecology and put the environmental criterion alongside the classical criterions of design. The goal of this study is to identify the specifications of a strategy for integrating the dimension “Environment”. This strategy is applied in the innovation process thanks to eco-design tools which are the learning vectors for an organization, and therefore support a learning process. This process is structured with the interactions between the management of firm, the environment department, and the design team. Therefore we first make a synthesis of the different classifications of eco-design tools and use two categories: diagnosis and improvement. Second, as our goal is the integration in the Innovation structure and within a design process, we analyze some design process models and highlight the RID (Research, Innovation structure, Development) concept. Third, the main practices of several car makers are synthetized and a focus on three of them (Volvo, Ford, and Volkswagen) is made; we link their strategies with the concept of RID. Finally in the fourth part, we propose a model of a strategy for integrating eco-design practices based on the three examples and supported by a learning process.

Topics: Green design
Commentary by Dr. Valentin Fuster
2012;():647-656. doi:10.1115/ESDA2012-82324.

When designing complex mechatronic systems, a team of developers will be facing many challenges that can impede progress and innovation if not tackled properly. In meeting them simulation tools play a central role. Yet it is often impossible for a single developer to foresee the overall impact a design decision will have on the system and on the other domains involved. For this task multi-domain simulation tools exists, but because of its complexity and the different levels of detail that are needed, the effort to specify a complete system from scratch is very high. Another challenge is the selection of the most suitable solution elements provided by the manufacturers. Currently they are often chosen manually from catalogues. The development engineer is therefore usually inclined to employ well-known solution elements and suppliers. To tackle both challenges our aim is an increase in efficiency and innovation by means of generally available solution knowledge, such as well-proven solution patterns, ready-to-use solution elements, and established simulation models [1].

Our paper presents a tool-supported, sequential design process. From the outset, the comprehensive functional capability of the designed system is supervised by means of multi-domain simulation. At significant points in the design process, solution knowledge can be accessed as it is stored in ontologies and therefore available via Semantic Web [2]. Thus, one can overcome barriers resulting from different terminologies or referential systems and furthermore infer further knowledge from the stored knowledge. The paper focuses on an early testing in the conceptual design stage and on the subsequent semantic search for suitable solution elements. After the specification of a principle solution for the mechatronic system by combining solution patterns, an initial multi-domain model of the system is created. This is done on the basis of the active structure and of idealized simulation models which are part of a free library and associated with the chosen solution patterns via the ontologies. In further designing the controlled system and its parameters with the completed model, the developer defines additional criteria to be fed into the subsequent semantic search for solution elements. Information on the latter is provided by the manufacturers as well as detailed simulation models, which are used to analyze the functional capability of the concretized system. Therefore, the corresponding idealized models are replaced automatically with the parameterized models of the solution elements containing for example the specific friction model for the chosen motor. We show this process using the concrete example of a dough-production system. In particular, we focus on its transport system. Resulting requirements for the simulation models and their level of detail are expound, as well as the architecture and benefits of the ontologies.

Topics: Design , Ontologies
Commentary by Dr. Valentin Fuster
2012;():657-664. doi:10.1115/ESDA2012-82328.

The paper deals with a functional approach to optimal dimensioning of automotive transmission shafts. In particular, the paper summarizes the results of a research activity developed on automotive transmission shafts to reduce the unpleasant movement of the transmission lever known as “shift lever movement”. The design problem was faced by focusing the axial clearances of the wheels assembled on the transmission shaft.

First, the functional approach to optimal dimensioning proceeds from the study of different working conditions of the automotive manual transmission and focuses on corresponding geometrical constraints and design parameters. Then, it uses simplified schemes, each of them related to a different working condition, to set a series of functional dimensioning loops for the transmission shaft. Subsequently, the approach introduces an appropriate index to evaluate the Information Content for each dimensioning scheme and it addresses the optimal dimensioning scheme, related to the minimization of the Information Content. After this, the approach foresees worst-case to check the axial clearances of the wheels assembled on the shaft. In a such way the effect of the dimensioning are directly evaluated in terms of performances of the transmission. In fact, the reduction of axial clearances for the wheels assembled on the shaft causes a direct reduction of the “shift lever movement”.

The functional approach to optimal dimensioning is applied to an automotive transmission set and the proposed dimensioning schema of the shaft is compared with different dimensioning schemes including one currently used in an international automotive company. A final discussion of the results, in terms of reduction of axial clearances of the parts assembled on the shaft, is provided.

Commentary by Dr. Valentin Fuster
2012;():665-674. doi:10.1115/ESDA2012-82350.

Within the last years mechatronics as a self-contained discipline doubtlessly shaped the development of technical systems. Mechatronics means the close interaction of mechanics, electronics, control engineering and software engineering in order to achieve a better systems behavior. Due to the outstanding deployment of information and communication technologies, the functionality of mechatronic systems will go far beyond the known standards with the intention to increase their robustness, flexibility and reliability. The objective is to develop intelligent systems that react autonomously on changing environmental conditions and optimize their behavior during operation. The design of such advanced mechatronic systems is a challenge. Additionally to mechanical, electrical, control and software engineers also expertise from mathematical optimization, artificial intelligence and even cognitive science is necessary. This requires an effective and continuous cooperation and communication between developers from different domains during the whole development process. As a consequence a domain-spanning methodology is necessary in order to guarantee an effective work flow between the participating developers from various domains and their domain-specific methods, terminologies and solutions. For this purpose an ontology-based computer support will be presented, that facilitates the systems engineer by analyzing the functional system model and identifying convenient solutions. This includes the generation and storage of once proven design solutions as well as the search for the effective and domain-spanning reuse.

Commentary by Dr. Valentin Fuster
2012;():675-682. doi:10.1115/ESDA2012-82409.

Product variety is necessary to satisfy the market. The change from a vendor market to a customer market has led to increased competition among manufacturers, benefiting the customer. Accordingly, less busy market niches are sought and more specific customer wishes are fulfilled. Rapid improvements or design of new products generate new incentives to buy. This market trend increases the variety of product variants while simultaneously leading to smaller number and lot size per variant. An increase in the number of variants and a decrease in the lot size tend to lead to longer throughput and delivery times and problems of quality assurance, and to higher direct and indirect costs per variant. The paper discusses this problem and provides a set of recommendations for controlling the multiplicity of variants within an enterprise.

Commentary by Dr. Valentin Fuster
2012;():683-694. doi:10.1115/ESDA2012-82420.

This paper proposes a method that dynamically improves a statistical model of system degradation by incorporating uncertainty. The method is illustrated by a case example of fouling, or degradation, in a heat exchanger in a cogeneration desalination plant. The goal of the proposed method is to select the best model from several representative condenser fouling models including linear, falling rate, and asymptotic fouling, and to validate and improve model parameters over the duration of operation. Maximum likelihood estimation (MLE) was applied to obtain a stochastic distribution of condenser fouling. Akaike’s Information Criterion (AIC) and the Bayesian Information Criterion (BIC) were then computed at time intervals to assess the accuracy of the MLE results. The degradation model was further evaluated by estimating future prognoses and then cross-validating with real world fouling data. The results show the accuracy of a prognosis can be improved substantially by continuously updating fouling model parameters. The proposed method is a step toward facilitating prognosis of engineering systems in the early design stages by improving the prediction of future component degradation.

Commentary by Dr. Valentin Fuster
2012;():695-702. doi:10.1115/ESDA2012-82467.

The purpose of this paper is to integrate the concept of the flexible link model (FLM) with a modified real coded quantum inspired evolutionary algorithm (MRQIEA) for the optimum synthesis of partially compliant mechanisms. The purpose is to synthesize the compliant and rigid members of a partially compliant mechanism in a single optimization run. The compliant member parameters are defined by the FLM which facilitates the integration of the design variables associated with compliant members and rigid links in one solution vector. Four examples are presented to demonstrate the approach.

Commentary by Dr. Valentin Fuster
2012;():703-709. doi:10.1115/ESDA2012-82470.

The paper deals with the design of a device for sound reproduction to be fixed to a supporting surface. The device is made up of two different types of acoustic actuators based on different technologies that allow good sound reproduction in the range of frequencies from 20Hz to 20kHz. The generation of sound at high frequencies is demanded to a magnetostrictive actuator, while a more traditional magnetodynamics actuator is used to generate sound at low frequencies. The coupling between these two actuators leads to a device having small overall dimensions and high performance.

Topics: Acoustics , Actuators , Design
Commentary by Dr. Valentin Fuster
2012;():711-718. doi:10.1115/ESDA2012-82476.

Layout design optimization has a significant impact in the design and use of many engineering products and systems, such as the subdivision of a ship, the layout of facilities in a plant or further still the assembly of parts of a mechanism. The search for an optimal layout configuration is a critical and complex task due to the increasing demands of designers working on varied projects. A layout optimization process is generally divided into different steps: the description, formulation and solving of the problem and the final decision. This process consists in writing an optimization problem that transform designer’s requirements into variables, constraints and objectives. Then, an optimization algorithm has to be used in order to search for optimal solutions that fit with product’s specifications. This paper focuses on the last step which consists, for the designer, in making a choice on the solutions generated by the optimization algorithm. This choice is made according to the global performances of the designs and also the personal judgment of the designer. This judgment is based on the expertise of the designer and the subjective requirements that could not be integrated on the formulation of the problem. This paper proposes a perceptive exploration method, based on an Interactive Genetic Algorithm (IGA), used to explore designs, taking into account the subjective evaluation of the designer. The objective of this method is to select an ideal solution that realizes the best trade-off between the quantitative and qualitative performance criteria. This interactive process is tested on an industrial layout application which deals with the search for an optimal layout of facilities in a shelter.

Commentary by Dr. Valentin Fuster
2012;():719-727. doi:10.1115/ESDA2012-82502.

The design of systems architectures often involve a combinatorial design-space made of technological and architectural choices. A complete or large exploration of this design space requires the use of a method to generate and evaluate design alternatives. This paper proposes an innovative approach for the design-space exploration of systems architectures. The SAMOA (System Architecture Model-based OptimizAtion) tool associated to the method is also introduced. The method permits to create a large number of various system architectures combining a set of possible components to address given system functions. The method relies on models that are used to represent the problem and the solutions and to evaluate architecture performances. An algorithm first synthesizes design alternatives (a physical architecture associated to a functional allocation) based on the functional architecture of the system, the system interfaces, a library of available components and user-defined design rules. Chains of components are sequentially added to an initially empty architecture until all functions are fulfilled. The design rules permit to guarantee the viability and validity of the chains of components and, consequently, of the generated architectures. The design space exploration is then performed in a smart way through the use of an evolutionary algorithm, the evolution mechanisms of which are specific to system architecting. Evaluation modules permit to assess the performances of alternatives based on the structure of the architecture model and the data embedded in the component models. These performances are used to select the best generated architectures considering constraints and quality metrics. This selection is based on the Pareto-dominance-based NSGA-II algorithm or, alternatively, on an interactive preference-based algorithm. Iterating over this evolution-evaluation-selection process permits to increase the quality of solutions and, thus, to highlight the regions of interest of the design-space which can be used as a base for further manual investigations. By using this method, the system designers have a larger confidence in the optimality of the adopted architecture than using a classical derivative approach as many more solutions are evaluated. Also, the method permits to quickly evaluate the trade-offs between the different considered criteria. Finally, the method can also be used to evaluate the impact of a technology on the system performances not only by a substituting a technology by another but also by adapting the architecture of the system.

Commentary by Dr. Valentin Fuster
2012;():729-737. doi:10.1115/ESDA2012-82538.

Energy consumption during the use phase often contributes significantly to the overall energy demand and to the environmental impacts of an elect(on)ic product’s lifecycle. Therefore, regulations, standards, and customers tend to demand that the electronic industry supplies products with lesser consumption. However, manufacturers lack of systematic methods and tools to integrate energy consumption into their design projects from the early design phases.

This paper presents the Synergico method which is meant to be incorporated in the current design practices of manufacturing companies, therefore helping design more energetically efficient electr(on)ic products without compromising the other design criteria (ergonomics, performances, usage value, quality, cost, delay, etc.). This method is based on three tools to use from the earliest design phases.

Firstly, an In-Use Energy consumption indicator providing an assessment of the energy consumption during the use phase during each design phase. Thanks to the consideration of several use scenarios, it calculates values of the product’s energy consumption for each product sub-assembly, and each operating mode, thus monitoring the consumption and compliance of a product with design objectives. Secondly, a Guideline-based tool adapted to electronic products. These guidelines can easily be filtered to consider only the most relevant ones according to the context (design phase, expert concerned, scope of the guideline, etc.). Thirdly, a Lifecycle Check tool to verify that no pollution trade-offs, between life cycle phases, would hinder the design of an energy efficient product with good overall environmental performances. A case study illustrates the use and integration of the Synergico method and the way it coordinates the tools.

Commentary by Dr. Valentin Fuster
2012;():739-744. doi:10.1115/ESDA2012-82577.

In Chinese Small and Medium-Sized Enterprises (SMEs), culture is one of the barriers which often plays an important role in the effective knowledge flow in their product design and development process. Investigations to designers from SMEs in China help us recognize several cultural barriers to this knowledge flow in the process of product design and development. This paper aims to identify those cultural barriers to knowledge flow in the design process of SMEs. Interviews with and questionnaires to designers from different SMEs were conducted. Empirical studies show that designers hesitate to share their knowledge; lack of trust and the thick wall among functional departments are major barriers influencing effective knowledge flows in the product design process. In addition, ongoing research on overcoming the identified cultural barriers to knowledge flow is also discussed briefly.

Commentary by Dr. Valentin Fuster
2012;():745-753. doi:10.1115/ESDA2012-82587.

Additive Manufacturing (AM) is a new way of part production which opens up new perspectives of conception as mass and cost reduction and increase of functionalities. However these processes have their own characteristics which as for all the manufacturing processes have a direct impact on the manufactured parts quality. Especially, because the manufacturing trajectories have a influence on the physical phenomena during the process, they have also a strong impact on the quality of the produced parts in terms of geometry.

In this paper, the choice of manufacturing trajectories and their impacts on the final shape and quality of the parts is integrated into a global Design For Additive Manufacturing (DFAM) methodology which allows to move from functional specifications of a design problem to a proposition of an adapted part for AM processes.

Commentary by Dr. Valentin Fuster
2012;():755-761. doi:10.1115/ESDA2012-82623.

In this paper we propose a new integration framework model for simplifying the feasible space exploration and product optimization in early design phases. Hence, modeling and optimizing tasks are core activities in this framework. Currently, system engineering problems are modeled and optimized using a wide range of domain-specific languages. One should not duplicate these languages by creating a new system engineering language capable of modeling and optimizing every aspect of a system. Thus we combine the UML2 language and the formalism of Constraint Optimization Problems (COPs). UML2 is a visual modeling language, which provides a set of diagrams and constructs for modeling the major aspects of a product. In order to optimize design parameters, we reformulate some of this modeling knowledge into a COP. A COP may be defined as a regular constraint satisfaction problem (CSP) augmented with a set of objective functions. Thus the optimization problem to be solved is stated declaratively with acausal constraints. Then, COP solvers are based on generic solving algorithms computing a set of optimal solutions. In this paper, generic concepts integrating variability modeling concepts and based on architecture description languages are introduced. We also briefly describe transformation strategy using ATL language to perform a bidirectional mapping between UML2 constructs and the corresponding COP models.

Topics: Design , Modeling
Commentary by Dr. Valentin Fuster
2012;():763-767. doi:10.1115/ESDA2012-82624.

Companies can have competitive advantage if their products are developed with the help of users and their practice in mind. Product development needs to include user views in the design [1] as the changes to product proposals in design stage needs less effort and time and has major influence on later stages. User-centered design methods have been proposed and implemented. Virtual reality technology has been developed to support these design methods. Advances in virtual reality technologies help realize virtually not only the products but the environment in which they can be used and the actors who use them. This research aims at investigating the eco-design methods and the technology supporting them. A huge challenge in eco-design is to make clear the environmental potential of products for both the engineer and the user. The paper deals with the use of virtual reality technology to see how it can help both designer and user in design and assessment of product and its use to reduce environmental impact. Different studies are reported in literature [2], [3], and [4] but do not address the environmental properties. The paper reviews the literature to propose the requirements of a user-centered eco-design method and investigates the potential benefits of the holographic technology for this purpose.

Topics: Design
Commentary by Dr. Valentin Fuster
2012;():769-776. doi:10.1115/ESDA2012-82728.

This paper presents the numerical study of double-lap bolted joint behavior. This type of joint is mainly used in aeronautical structures to transfer the given loads (by both adhesion and by deformation-shearing). Recent articles, based on experimental fatigue tests conducted by AIRBUS, have shown the beneficial effects of preloading on the fatigue life of these joints.

Finite element analyses were performed using ABAQUS® to study the behavior of a double-lap single-bolted joint with different plate thicknesses (joint thickness = 0.5d, 1d, 1.5d, 2d 2.5d, 3d, 3.5d and 4d, where d is the bolt diameter).

The numerical model provides several important results. In the case of static loads, elasto-plastic constitutive laws of the bolt and the plate materials allowed the process to be simulated on the basis of tension tests.

Mechanical aspects of this type of assembly are numerically identified; from the initial state of adhesion to the state of plastic deformation of parts in contact including the stage of generalized slippage. We note that the fracture load increases slightly when the bolted joint is preloaded while the failure area remains the same. In the case of large plate thickness, the connection is subjected to significant bending stresses and this involves strong local plasticization associated with the loss of preload.

In the case of cyclic loading, we consider a numerical model based on the simulation of one loading/unloading cycle. A noticeable decrease in initial preload is observed for certain configurations, in particular those with the largest plate thickness. This phenomenon is related to the effect of strain hardening of the bolt during the first loading cycles. Some experimental work by AIRBUS has shown that the fatigue life of assemblies is dependent on the material plate thicknesses.

An extension to the case of a multiple-bolted joint (three rows of three bolts) is finally discussed and highlights the evolution of the rate of load transmission with respect to the applied load.

Commentary by Dr. Valentin Fuster
2012;():777-783. doi:10.1115/ESDA2012-82773.

Product design involves a multitude of actors who have complementary knowledge and responsibility about the product under development.

Coupling together their views-points, particularly these of product designers and engineering designers in the upstream phases of the design, has the objectives to make the collaboration easier and to improve the product from both of their expertises.

The Product/Process multi-view model is a collaborative tool which supports engineering designers during product development processes. It allows the structuring and tracing of relative knowledge of engineering designers on the product. We make the assumption that Product/Process multi-view model could also be used to create relationships with the product designer’s representation.

The paper deals with this product model and illustrates the possible connection between engineering knowledge and product design knowledge.

Topics: Product design
Commentary by Dr. Valentin Fuster
2012;():785-794. doi:10.1115/ESDA2012-82811.

The issue of improving quality, costs and delays indicators in design and manufacturing is more relevant than ever in the industry. After lean manufacturing, well known in production process, the lean engineering approach is being implemented today in the field of design, taking the name of lean product development.

The management of knowledge and know-how (existing, new or to be acquired) is the heart of lean engineering. In our suggested methodology this is implemented through a new generation of tools called Knowledge Configuration Management (KCM) and Knowledge Extraction Assistant (KEA).

KCM tools are lean engineering components that provide analytical approach to knowledge management and knowledge-based engineering. These tools require a highly integrated approach that involves, for example, predefined geometrical parametric 3D models, such as CAD templates. But this approach cannot be deployed in all engineering sites.

We propose to complete this KCM approach introducing a semantic network approach, coupling with Feature Identity Card (FIC). FIC contains a set of metadata and information existing in the Product Data Management (PDM), connected with information extracted from 3D CAD (Computer Aided Design) models. It allows contextualizing information and ensures semantic connections, in order to manipulate the right parameters with mathematical algorithms. Those algorithms will search candidate relationships between design parameters extracted from CAD models.

Our suggested approach aims at extracting knowledge in cases where design never came out of Knowledge Based Engineering (KBE) applications. In those situations, it seems important to complete classical knowledge management approach, and to find out the implicit knowledge embedded in 3D CAD models. This is achieved through a global approach, focusing on the product’s 3D definitions.

We suggest introducing the latter approach by a suite of digital KEA tools (interfaced with KCM tools). Extracting knowledge from projects information stored in the Product Data Management does this.

More precisely, the methodology is based on a commercial 3D similarity search tools for CAD models and on mathematical algorithms that search relationships between extracted design parameters. The goal is to submit new rules to the process and design experts.

Implementing this methodology, a deeper knowledge of the product and its associated process can be acquired. This ensures a more productive and efficient design process.

Commentary by Dr. Valentin Fuster
2012;():795-800. doi:10.1115/ESDA2012-82923.

The paper presents a framework for the assessment of mass customization and sustainability performance of enterprises and supply chains. The assessment includes the product, process, enterprise and supply chain levels while considering the product life cycle phases. This two perspectives approach ensures a quite complete assessment and provides guidance to designers and managers during the decision making process. The framework construction and use methods are depicted in the current paper.

Topics: Sustainability
Commentary by Dr. Valentin Fuster
2012;():801-811. doi:10.1115/ESDA2012-82947.

Nowadays, economical, technical and ergonomic factors have a great importance on the design of the agricultural tractors. The paper illustrates the use and the management of heterogeneous product information (manual measurements and drafts, 2D drawings, technical documentation, photos), advanced CAD modeling tools and digital human models, for the redesign and the ergonomic optimization of an agricultural tractor’s driver cab. The project development has been organized using a top–down approach in a collaborative environment. At first, a manual measurement with gauges allowed to realize a technical draft of the whole agricultural tractor and of each component part of the driver cab. Then a main skeleton has been created in Catia V5 environment in order to specify all the datum elements necessary to model each sub-assembly of the tractor. Cabin, platform, engine, tires, seat, dashboard and controls have been organized separately and modeled considering the details related to the manual measurements and to the technical standards. Once obtained the 3D CAD model of the tractor, an opportune questionnaire was prepared and a test campaign was carried out with real operators in order to define the more critical control devices within the driver cab, as regards to usability and ergonomic issues. An “Ergonomics’ Evaluation Index” (EEI) was defined taking into account the posture angles of the operator and the Rapid Upper Limb Assessment analysis tool available in the “Ergonomics Design & Analysis” module of Catia V5 based on the use of a digital human model. The index was validated comparing the results of tests carried out using virtual manikins of different percentiles performing a specific driving task, with the results of tests carried out by real operators, of the same percentiles, performing the same driving task. Critical values of the EEI obtained during some driving tasks in virtual environment, suggested to modify the shape and the position of some control devices in order to optimize the ergonomics of the driver cab. The adoption of the top-down modeling based approach allowed each change on a singular component part to be automatically propagated on the whole assembly, making easy the changes on the virtual prototype.

Topics: Optimization
Commentary by Dr. Valentin Fuster
2012;():813-822. doi:10.1115/ESDA2012-82982.

Smart products are becoming more present in everyday life. They are prevalent in different markets such as electronic devices, cars and household appliances. One important dimension of product smartness is “multi-functionality”. When choosing a product, the consumer takes into account subjective and objective purchase drivers. Price, brand, aesthetics, environmental impact and functionalities represent an important set of these. In this context the work are interested in correlating two drivers: functions and eco-sustainability. Generally, this last characteristic should be maximized taking into consideration a correct balance with product functionalities. The aim of this work is to investigate this correlation. It can be measured by a suitable correspondence in order to determine a quantitative law. This relationship can be useful to the designers to determine the product features during the product design phase, but it can be also used by consumers to compare similar products. This paper reports the problem domain, approach for correlation law definition and, finally, the experimental analysis of product functions vs. environmental sustainability. Two case studies in the household appliances sector will exemplify the proposed analysis.

Commentary by Dr. Valentin Fuster
2012;():823-831. doi:10.1115/ESDA2012-83004.

Today in the wind turbine global analysis codes such as Hawc2 [1] or FAST [2], the entire gear train is modelled by one degree of freedom constant stiffness torsional spring. This is because the focus in the global analysis programs lies mainly on the aerodynamic loads and the dynamic behaviour of structural members. For the small size gear trains, since the internal natural frequencies are expected in a frequency range above the overall wind turbine harmonics, this approach can be justified. However, as the industry trend is toward the larger drivetrains in offshore developments, the internal dynamic of gear trains are required to be modelled more accurately. Moreover, the development in generator technology with low, medium and high speed options has brought a variety of gear train design options with specific dynamic behaviour.

In this paper the natural modes and internal dynamic excitations of high ratio wind turbine gear trains is investigated. Case study gear trains of 0.6, 2, 5 and 10 MW are modelled by pure torsional elements in a Multi Body Simulation (MBS) program; Simpack [3], where the natural modes are obtained and possible excitation are evaluated. The results show the resonance trend in various size wind turbine gear trains.

Commentary by Dr. Valentin Fuster
2012;():833-839. doi:10.1115/ESDA2012-83017.

Model-based systems engineering (MBSE) is an approach to improve traditional document-based systems engineering approach through the use of a system model. In the current practice of system developments, there exists a large gap between systems engineering activities and engineering analyses, because systems engineers and engineering analysts are using different models, tools and terminology. The gap results in inefficiencies and quality issues that can be very expensive. This work presents an integrated modeling and analysis capability that bridges the gap. The technical approach is based on integrating SysML modeling tools with process integration and design optimization framework. This approach connects SysML models with various engineering analysis tools through a common interface. A capability was developed to automatically generate analysis models from a system model and then execute the analytical models. Requirements conformance analysis was performed using results of engineering analysis. A technique was developed to define optimization problems in SysML, where requirements were used as design constraints. The integrated system modeling and analysis capability was demonstrated using an automobile brake pad design example. The integrated toolset was used to understand impacts of requirements changes in the SysML model and to find a new design that meets the new requirements through engineering design optimization.

Commentary by Dr. Valentin Fuster

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