ASME Conference Presenter Attendance Policy and Archival Proceedings

2018;():V001T00A001. doi:10.1115/ISPS-MIPE2018-NS.

This online compilation of papers from the ASME-JSME 2018 Joint International Conference on Information Storage and Processing Systems and Micromechatronics for Information and Precision Equipment (ISPS-MIPE2018) 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presenter attendance policy, if a paper is not presented at the Conference by an author of the paper, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.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

Head/Media Interface and Tribology

2018;():V001T01A001. doi:10.1115/ISPS-MIPE2018-8515.

The structural and molecular weight changes to lubricant picked up following laser heating in heat-assisted magnetic recording (HAMR) were analyzed using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The intensity of the ion mass fragments depended on the decomposition pathways and changed drastically, as did the average molecular weight of the picked-up lubricant as heating temperature increased. The fragment series formed by the dissociation of end groups with low molecular weights (CH3O+) showed a high intensity at temperatures under 300 °C, whereas at temperatures over 400 °C, the fragments series formed by the dissociation of the end-group component (C5H9O4F2+) increased. Overall, the results presented herein suggest that the chemical and thermal stability of the hydrocarbon terminal ends of lubricants should be improved in order to decrease depletion of the lubricant film and lubricant pickup by laser heating in HAMR.

Commentary by Dr. Valentin Fuster
2018;():V001T01A002. doi:10.1115/ISPS-MIPE2018-8519.

We formulated the surface pressure of a disk surface that consists of three layers of diamond-like-carbon (DLC) as well as bonded and mobile lubricants based on the asperity adhesive contact theory. We demonstrated that this surface force could well evaluate the touchdown behaviors of a thermal fly-height control (TFC) slider. This theory shows that the touchdown behaviors of a current TFC femto-slider are mainly governed by the asperity meniscus force rather than the van der Waals force (vdW). However, it is shown that the static instability of a pico-slider was generated from the vdW force. Moreover, it is estimated that the dynamic instability of the pico-slider was mainly caused by the meniscus force rather than the vdW force. This surface force theory can allow us to understand consistently various phenomena of slider dynamics.

Commentary by Dr. Valentin Fuster
2018;():V001T01A003. doi:10.1115/ISPS-MIPE2018-8527.

In this study, we experimentally investigated the lubricant depletion caused by pulsed-laser irradiation heating and discussed the fundamental characteristics, comparing it with the results obtained by continuous laser heating. As a result, it was found that the decrease in the lubricant depletion due to pulsed-laser heating was smaller than that to continuous laser heating and depended on an increase in the duty ratio as it increased. In addition, the lubricant depletion depends on the full width at half maximum (FWHM) of the temperature distribution due to pulsed-laser irradiation heating and increased as the FWHM increased. Therefore, it is also suggested that the lubricant depletion issue will not be so critical in actual HAMR systems because the FWHM would be very small.

Commentary by Dr. Valentin Fuster
2018;():V001T01A004. doi:10.1115/ISPS-MIPE2018-8533.

Coarse-grained models were developed to study the evaporation and transfer of the perfluoropolyether lubricant from the disk surface under laser heating. Both moving and stationary disks were simulated with a heat flux applied to a central region under a pad. A novel concept of a reconditioning region was proposed to convert the periodic boundary conditions to more realistic conditions with the fresh material fed at the inlet. The results indicate significant influence of the disk velocity, heat flux and gap distance on the evaporation and transfer of the lubricant. With increasing heat flux, more lubricant molecules tend to reach the slider surface.

Commentary by Dr. Valentin Fuster
2018;():V001T01A005. doi:10.1115/ISPS-MIPE2018-8537.

A plasmonic Surface-enhanced Raman Spectroscopy (SERS) sensor has been used for emulation of Near Field Transducer (NFT) in Heat-Assisted Magnetic Recording (HAMR). Laser heating mechanism by the sensor is the same as that by NFT with electro-magnetic near-field or plasmonic field, which is different from far field heating.

Heating behavior for a lubricant film on a carbon overcoat for a hard disk medium was observed using Surface-enhanced Raman Spectroscopy with the plasmonic SERS sensor. Spectral change of lube films in laser heating with a continuous power changer was measured with heating temperature, calculated by anti-Stokes/Stokes intensity ratio in Raman spectra. As a result, it is found that the lubricant film composed of a tetraol perfluoro-polyether (PFPE) is evaporated above 290°C, which shows good agreement with that by TGA (Thermogravimetric Analysis).

The evaporation occurs in wide range of spacing between the lubricant film and the SERS sensor from 0 (contact) to 50nm, and more. After laser heating, lubricant film with free surface in a large gap area, i.e. spacing of 3nm, is recovered with elapsed time. However it is difficult to be recovered in confined (contact) area, because lubricant mobility is small. Lost lubricant can be recovered in head flying by surface diffusion or centrifugal force during disk rotation.

Topics: Sensors , Transducers
Commentary by Dr. Valentin Fuster
2018;():V001T01A006. doi:10.1115/ISPS-MIPE2018-8545.

The head disk spacing in state of the art hard disk drives has been successfully scaled down to a couple of nanometers and is accurately controlled, providing a workable condition for near field devices, such as near field transducers (NFT) and plasmonic sensors. Heat assisted magnetic recording (HAMR) uses an NFT to generate the localized electromagnetic field to heat the media above the Curie temperature. The coupling between the NFT and the magnetic media has a strong spacing dependency, explained by the nature of the evanescent field. In this paper, we discuss how the spacing dependency is accurately calibrated and the applications of this spacing dependency in HAMR, such as static and transient protrusion measurement and compensation and fly height variation measurement.

Commentary by Dr. Valentin Fuster
2018;():V001T01A007. doi:10.1115/ISPS-MIPE2018-8569.

In the present paper, the flying characteristics of a step slider flying in either air or He with a local temperature distribution of the disk are analyzed using the thermo-molecular gas-film lubrication (t-MGL) equation in the quasi-free-molecular flow region (quasi-free-molecular t-MGL equation: t-MGLqfm eq.). The gas temperature in the t-MGLqfm equation, τG, is assumed to be that in the free molecular limit, τGfm, defined by temperatures and accommodation coefficients at the disk, τW0, α0, and those at the slider, τW1, α1, respectively. The decreases in static spacing for the slider flying in He are significant. Moreover, the spacing decreases as the accommodation coefficients of the disk, α0, decreases, that is, as the ratio of specular reflection increases. The spacing fluctuation caused by a running wavy disk varies according to both the ambient gas (air/He) and the boundary accommodation coefficients.

Commentary by Dr. Valentin Fuster
2018;():V001T01A008. doi:10.1115/ISPS-MIPE2018-8579.

The contact potential across the head-disk interface is investigated. AC voltage was applied to the disk surface using a mercury connector located at the top of the spindle, keeping the recording head grounded. The acoustic emission (AE) and touchdown sensor (TDS) amplitude was measured as a function of the DC offset voltage to determine the contact potential across the head-disk interface at which the AE and TDS signals, respectively, becomes a minimum. The contact potential across the head-disk interface is studied as a function of temperature, relative humidity, and wear of the head-disk interface.

Topics: Disks , Probes
Commentary by Dr. Valentin Fuster
2018;():V001T01A009. doi:10.1115/ISPS-MIPE2018-8583.

This paper investigates how corrosion growth that originates from shallow film voids on thin film sputtered magnetic media can impact the final HDD system performance. The impact of shallow void corrosion [1] in HDD system can be both on its behavior during initialization i.e. servo write formatting and initial defect mapping, and on its long term reliability. One of the main concerns for HDD reliability due to media is the occurrence of a condition called metallic smear. Metallic smear is a contamination of the head-pole area that causes an unstable fly height condition. Metallic smear is possibly caused by media corrosion and therefore void corrosion is a logical concern. However, our study shows that shallow void corrosion is not associated with metallic smear risk and does not contribute to HDD initialization failures.

Commentary by Dr. Valentin Fuster

Motor Mechanisms and Servo Control

2018;():V001T02A001. doi:10.1115/ISPS-MIPE2018-8531.

In this paper, we propose and perform the robust design optimization (RDO) algorithm for the shape of the BLDC motor used in the electric oil pump. The proposed RDO algorithm improves the torque characteristics of the BLDC motor to improve the performance of the electric oil pump. The previous deterministic design optimization (DDO) method derives an appropriate combination of the design goal and the specific target performance. However, not only the target performance but also other performance constraints must be considered for RDO. To overcome these problems, we consider the penalty function. In conclusion, we can confirm the improvement of the torque characteristics of the BLDC motor used in the EOP by using the proposed RDO algorithm.

Commentary by Dr. Valentin Fuster
2018;():V001T02A002. doi:10.1115/ISPS-MIPE2018-8549.

In this research, we aim to examine the usefulness of the newly developed spindle motor proposed by Ochiai. Since machining error due to tool wear etc. used for microfabrication can be ignored, laser processing was used as a processing method. Thrust bearing grooves were generated by laser processing, and variation in groove depth was observed. Finally, the optimum shape of the thrust bearing groove was obtained by robust optimization using the probability distribution that can be approximated from the obtained machining error.

Commentary by Dr. Valentin Fuster
2018;():V001T02A003. doi:10.1115/ISPS-MIPE2018-8567.

In many motion control problems of mechatronic equipment, the control performance of the final-state of the control period is strictly important for positioning or settling issues. Totani and Nishimura proposed a final-state control (FSC) method using compensation input for such a purpose in 1994. The FSC technique has been improved and applied to various kinds of actual mechanical motion control problems. The FSC technique looks similar to the Mode Predictive Control (MPC). However, the difference of FSC and MPC has not been fully addressed yet. This paper shows the understanding of FSC technique from the viewpoint of the MPC theory. An updating-type FSC (UFSC) proposed by a part of the authors is introduced. Then, this paper shows analytically that the control input in UFSC can be obtained by the theory of MPC under some conditions. This analysis makes clear the meaning of “updating” in the FSC technique for actual mechanical motion control applications.

Commentary by Dr. Valentin Fuster

Micro/Nanomechatronics and Intelligent Machines

2018;():V001T04A001. doi:10.1115/ISPS-MIPE2018-8504.

The positioning accuracy of magnetic heads need to be improved to increase the recording capacity of hard disk drives. In our previous study, the experimental results confirmed that the head positioning error could be decreased by attaching linear protrusions on the leading edge of the carriage arms. However, the mechanism underlying the phenomenon has not been elucidated. In the current research, we evaluated the effect of leading-edge protrusions on the flow-induced carriage excitation force using the finite element (FE) method analysis and the Hilbert-Huang transform (HHT). We prepared two carriage-arm FE models, with and without linear protrusions, on the leading edges of the arm, and performed the FE analyses. Subsequently, we conducted a frequency analysis by applying the HHT to the simulated torque-disturbance time series of each FE model and the results were later compared. Our results show that the leading-edge protrusions were found to decrease the mean velocity between the arm and the disk, thereby decreasing the vorticity fluctuation in the arm hole, and to decrease the fluctuations in pressure on the outer sidewall of the carriage arm around the coil support.

Commentary by Dr. Valentin Fuster
2018;():V001T04A002. doi:10.1115/ISPS-MIPE2018-8540.

In this research, as a different approach to the conventional one which enhances the performance with hardware of a haptic device, we adopt another approach to make the brain feel as if the person is touching the real thing via an illusion. Thus, we study Velvet Hand Illusion (VHI) which is an illusionary phenomenon concerning tactile touch. In VHI, a hexagonal wire mesh is sandwiched between both hands and rubbing the wire mesh without relative motion between both hands generates a smooth feeling, like velvet. The brain activation at this time is measured by PocketNIRS, which contains two channels measuring the bilateral prefrontal cortex. We obtained the result that the prefrontal cortex was activated to roughly two times larger when VHI occurred than when touching real velvet fabric. Since different responses can be obtained in the prefrontal cortex during brain activation between real velvet and VHI, it is possible to use pocketNIRS for the evaluation of VHI.

Commentary by Dr. Valentin Fuster
2018;():V001T04A003. doi:10.1115/ISPS-MIPE2018-8550.

In recent years, the methods of motor learning using haptic devices that can give motion-related stimuli to learners have been studied. In order to design control systems of the haptic devices that can give learners stimuli so that they can perceive them with proprioception, we need to understand the characteristics of human’s position and velocity sensations. Then, in this study, we examined velocity JNDs (Just Noticeable Differences), in order to understand human velocity-change perception. We, in particular, focused on an effect of acceleration during velocity-change to human velocity-change perception. In the experiment, we enforced subjects to accelerate their hands with a constant acceleration of 1, 8, 16, 32 deg/s2 from before-acceleration velocity of 10 deg/s. Subjects answered whether they perceived velocity-change or not, and we measured velocity JNDs. As a result, it was found that, while the accelerations increased by 32 times, the velocity JNDs decreased by only about 1/2, i.e., from 8.1 to 4.2 deg/s. From this result, it was concluded that the magnitude of acceleration is not a determinative factor for velocity-change perception but a supplementary one.

Commentary by Dr. Valentin Fuster

Biomedical Equipment, Medical Robotics/Devices

2018;():V001T05A001. doi:10.1115/ISPS-MIPE2018-8503.

A resin-based optical total analysis system (O-TAS) which consists both of microfluidic channels and light waveguides [1] is thought to be one of the most promising components in developing a “ubiquitous human healthcare system” in the near future. Along with this technology trend, we have already developed a transparent epoxy-resin-based optical TAS chip which has a specially prepared light waveguide structure of radially arranged configuration at an intersection portion with a microfluidic channel, in order to detect directivity of fluorescence from fluorescent substance attached micro particles [2],[3]. Schematic diagram of the optical TAS is shown in Figure 1. In the latest research, utilizing an AC modulated laser source and time-series averaging function on detected signal waveforms, we could have successfully obtained directivities of fluorescence from 5-μm-diameter particles with higher signal to noise (S/N) ratio [3].

Commentary by Dr. Valentin Fuster
2018;():V001T05A002. doi:10.1115/ISPS-MIPE2018-8535.

In this paper, we proposed a novel electromagnetic targeting system using rotating magnetic-flux concentration method for navigating endo-bronchoscope. This system consists of a magnetic-flux emitting coil, a magnetic-flux receiving electromagnets-array, a 2D model of bronchial tree, the magnetic-flux concentrator embedded on brush-guiding tube which was connected to the guide sheath. When the concentrator in the 2D bronchial tree passes through the air gap between the emitting coil and the receiving electromagnets-array, the concentrator concentrates the magnetic flux between the coil and the array. The concentrated magnetic flux is subsequently received by the receiving electromagnets-array and thus stable voltage output is produced. Furthermore, when the concentrator is rotated, the concentration of the magnetic flux is periodically changed and thereby the voltage output is periodically changed. By analyzing the voltage changes, the location of the concentrator (as well as guide tube and sheath) is targeted. According to the experimental results, the system successfully targets the location of the guide sheath in the 2D model of bronchial tree.

Topics: Magnetic flux
Commentary by Dr. Valentin Fuster
2018;():V001T05A003. doi:10.1115/ISPS-MIPE2018-8536.

In this paper, we report a finite element modeling of an electromagnetic-coils targeting system to locate a distal screw-hole in intramedullary interlocking-nail surgery. The system consists of an internal coil, external coil, and control/measurement electronics. The internal coil is embedded in a distal screw-hole of the nail inserted into the bone. A current is applied to the internal coil to produce a directional magnetic flux penetrating the nail/bone. Thus, the external coil scans different regions of the nail/bone will receive different amount of magnetic flux, and thereby produces different voltage outputs due to the electromagnetic induction. By analyzing the voltage outputs, the distal screw-hole is targeted. However, to precisely apply this system to many different nails for people in different regions, modification and optimization of the system are needed. For rapid modification and optimization, we implement finite element method to model the targeting system. Because the modeling results are qualitatively consistent to experimental results, the modeling is successfully validated to be able to qualitatively predict experimental trends and thereby can be used for rapid system modification and optimization.

Commentary by Dr. Valentin Fuster
2018;():V001T05A004. doi:10.1115/ISPS-MIPE2018-8562.

This paper studies the effect of thin film thickness on visibility readout from an interferometric pressure sensor. Interference fringes between a silicon nitride diaphragm and a glass substrate are formed as a function of pressure and can be captured using a camera. Image processing software was used to analyze and correlate the fringe pattern to pressure. Visibility of the interference fringes is optimized by depositing a thin silicon nitride layer on the glass substrate of the sensor using plasma enhanced chemical vapor deposition (PECVD). Optimal visibility was obtained with a coating thickness of 79 nm. Visibility was increased by 150% in comparison to no coating.

Commentary by Dr. Valentin Fuster
2018;():V001T05A005. doi:10.1115/ISPS-MIPE2018-8578.

Luminal esophageal temperature monitoring is of high importance during catheter ablation surgeries of the left atrium. A device is currently under development to accurately measure temperature of the inner esophageal wall. Ex vivo tests using porcine esophageal and left atrial tissue have been set up and performed to better understand heat flow through the biomaterials in contact. To compliment ex vivo experiments, a numerical analysis using thermal finite element analysis has been implemented to compliment ex vivo experiments with a numerical study of the temperature distribution across tissue layers as a function of tissue thickness, as well as heat source contact size and time. Both the ex vivo experiments and finite element simulations aid in development of a practical prototyped device for potential use during catheter ablations.

Topics: Temperature
Commentary by Dr. Valentin Fuster

Flexible Media Handling Machines and Printed Electronics, Imaging, and Printing Technologies

2018;():V001T07A001. doi:10.1115/ISPS-MIPE2018-8510.

Printed electronics is a next-generation process technology that is suitable for high speed and high volume production and can make electronic devices and circuits on flexible materials. To commercialize printed electronics, it is necessary to improve the alignment precision of printing. In order to improve the alignment precision of the roll-to-roll process, accurate measurement of the web position is required. Therefore, in the previous research of this paper, we proposed a measurement system of the moving direction and the lateral movement using an encoder. However, in the previous study, the direction of error control had to be set according to the measurement position of the encoder, and the measurement range was so narrow. In this paper, we propose a measurement system that can detect the direction of error and increase the effective measurement range using the burst alignment pattern that generates the burst signal. Applying it to roll-to-roll printing position measurement systems, measurements can be performed with greatly improved efficiency and measurement range.

Commentary by Dr. Valentin Fuster
2018;():V001T07A002. doi:10.1115/ISPS-MIPE2018-8511.

Printed electronics is a technology for making electronic devices using functional ink and flexible material film. The roll-to-roll printed electronic process is a next-generation process that is environmentally friendly and mass-productive at low cost. However, if the printing pressure between two rolls cannot be made uniform in the roll-to-roll process, it is difficult to commercialize the printed electronics due to the degradation of the printing quality. Previous study has proposed a method to select the initial condition that minimizes the printing pressure change using shape information of the roll and minimized printing pressure is verified by using the load cell signal. However, repetitive pressure errors that occur as the roll rotates require printing pressure uniformization control. In this paper, the printing pressure is predicted by using the shape information of the roll, and adaptive feedforward control is performed based on the predicted result to uniformize the printing pressure. Then, the experimental results are verified using a load cell signal.

Commentary by Dr. Valentin Fuster
2018;():V001T07A003. doi:10.1115/ISPS-MIPE2018-8532.

In this study, we present a sync detection optical layout that can reduce the periodic noise of the color printing system. A color printing system which applies tandem type laser scanning unit exposes light onto four photo conductive drums using four laser diodes and a single polygon mirror (PM). In order to reduce the image moire caused by the periodic noise of the shape error of the PM according to the color superposition method, optical analysis on various shape errors of the polygon mirror was performed. In this study, we propose a sync detection layout which can solve the color moire caused by peak-to-valley (PV) shape error of polygonal mirror surface.

Commentary by Dr. Valentin Fuster
2018;():V001T07A004. doi:10.1115/ISPS-MIPE2018-8541.

We examined the behaviors of the paper sheet in an overlap-type sheet separation mechanism and a pressing-type sheet separation mechanism. First, we introduced the models that can calculate the resistance force and feed force acting on the paper sheets in both sheet separation mechanisms. And, based on the calculation results of the resistance force and friction force between the paper sheets, we studied the behavior of the paper sheet in each separation mechanism. As a result, we found that an overlap-type sheet separation mechanism is superior to the pressing-type sheet separation mechanism but it is easily influenced by the feeding force caused by pick-up rollers, and also a pressing-type sheet separation mechanism has robustness for a thickness of paper sheet and for a feeding force caused by pick-up rollers.

Commentary by Dr. Valentin Fuster
2018;():V001T07A005. doi:10.1115/ISPS-MIPE2018-8563.

Plastic films are produced using roll-to-roll systems, which allow the film to be wound into a roll and stored in a small space. Roll defects, however, can cause significant economic loss, and gage bands remain an open area of research. More recently, plastic films have become thinner, so we must now reconsider wrinkling and slippage, problems which depend on the in-roll stress condition. Therefore, predicting the stress condition is essential to preventing defects occurring in wound rolls. In addition, the in-roll stress will change over time as a result of viscoelastic properties. This study theoretically investigates and experimentally verifies winding condition optimization and in-roll stress in consideration of the viscoelastic property and web thickness profile at a constant rewinding tension. Results show that the predicted values are in agreement with the measured values.

Commentary by Dr. Valentin Fuster
2018;():V001T07A006. doi:10.1115/ISPS-MIPE2018-8565.

This paper deals with the influence of surface contamination on the frictional mechanisms of rubber rollers. The contamination which adhered on the rollers after feeding many sheets of papers is one of the predominant causes of paper jams. However, the mechanism has not been understood. The purpose of this paper is to clarify the relationships between the friction force and the real contact area of papers and contaminated rubber rollers. Carrying out paper feeding tests by using a commercial multifunction peripheral, we tested different types of papers produced by different manufacturers. The tests have been done with combinations of different manufacturer’s papers and different kinds of roller materials. Observations of the real contact area clarified that the roller surfaces covered with paper powders or lint reduces the friction coefficient.

Topics: Friction , Wear , Rubber , Rollers
Commentary by Dr. Valentin Fuster
2018;():V001T07A007. doi:10.1115/ISPS-MIPE2018-8574.

In this research, the fabrication of polymer ultra-thin films (nanosheets) using a micro gravure printing method was studied. The effects of the conveying speed of the plastic film substrate, the concentration of solution and rotating speed of the micro gravure roll on the film thickness of the nanosheets were investigated through experimental approach. The polyethylene terephthalate film was placed as a substrate by a roller. After applying the tension load directly to the film, polyvinyl alcohol was coated on the PET film in order to release the nanosheets from the PET film by the sacrificial layer method. After that, polylactic acid (PLLA) was coated. Thickness of nanosheets was measured by using a stylus type surface profile. In addition, in the micro / nano field, nanoimprint technology is capable of pressing a mold having an irregular pattern of several tens nanometer level onto a resin. In order to further enhance the functionality of the nanosheets, the press method and the roll nanoimprinting method can be used to produce a fine structure, and press the nanosheets without heating. As a result, since the shape of the mold could be transferred, it is possible to fabricate the nanosheets with the microstructures by the roll nanoimprinting method. In the case of fabricating porous nanosheets by the roll nanoimprinting method, the microstructures were smaller than a hot press method. And the pressed microstructures on the nanosheets without heating were smaller than the microstructures with heating.

Topics: Manufacturing
Commentary by Dr. Valentin Fuster
2018;():V001T07A008. doi:10.1115/ISPS-MIPE2018-8582.

The aim of this paper is to investigate the effect of roller leveling process on the behavior of microstructure in flexible magnetic medium. Linear magnetic encoder is a highly precise measuring device that required accurate quality control during manufacturing. Previous studies have demonstrated the feasibility of roller leveling application to enhance the manufacturing of flexible magnetic medium. Mechanical shape defects in magnetic medium occurred during manufacturing due to environmental conditions can be eliminated through roller leveling process. In this paper, further steps were taken to understand the effect of roller leveling process in the microstructural level. From experimental results, it demonstrates that roller leveling process, a type of cyclic loading process, would not encourage crack growth if cracks were not initiated prior to leveling process. In addition to removing mechanical shape defects, understanding roller leveling process in magnetic medium application through investigating microstructure behavior has implications toward the fabrication quality of flexible magnetic medium.

Topics: Rollers
Commentary by Dr. Valentin Fuster

Micro/Nano System Science and Technology

2018;():V001T08A001. doi:10.1115/ISPS-MIPE2018-8502.

In this paper, we report a novel nanoelectromagnetic system using multiferroic/magnetoelectric Ni-nano-chevron/PMN-PT heterostructure to demonstrate an electric-field-controlled permanent magnetic single-domain transformation. The heterostructure consists of a magnetostrictive Ni-nano-chevron, Pt top and bottom electrodes, and a piezoelectric PMN-PT substrate. In initial state (as demagnetized), the magnetization of the magnetic single-domain is stably along the long axis of the nano-chevron. A magnetic field of 3000 Oe (along 45 degree of nano-chevron) is applied to magnetize the Ni-nano-chevron from stable single-domain to metastable two-domains. After this, an electric field of 0.8MV/m is applied to the PMN-PT substrate to produce the converse magnetoelectric effect to transform the two-domains. After the electric field is removed, the two-domains are further transformed back to the single-domain. Finally, when comparing the domains before and after applying our approach, approximately 50 % of single-domains are successfully and permanently switched (i.e., magnetization-direction is permanently rotated 180 degrees).

Commentary by Dr. Valentin Fuster
2018;():V001T08A002. doi:10.1115/ISPS-MIPE2018-8516.

A method to calculate the stress distributions in the elastic body caused by the molecular interactions has been established. The stress distribution was calculated based on the Mindlin’s solution considering the one-dimensional periodic material distribution. The calculation results for a distribution of two materials were presented. The basic characteristics of the stress distribution in the elastic body were quantitatively clarified.

Topics: Stress
Commentary by Dr. Valentin Fuster
2018;():V001T08A003. doi:10.1115/ISPS-MIPE2018-8529.

We have developed a metal-cantilever electrostatic vibration power generator that has comb-drive electrodes made of a SOI wafer at the tip of the cantilever. The comb-drive electrodes in which built-in electric field is given by potassium ion electret technique acts as an energy transducer from mechanical vibration power to electrical one. The metal cantilever part is formed separately, and assembled with the comb-electrodes on a bakelite plastic. This device showed strong nonlinear frequency responses, in which spring hardening was observed when applied acceleration was small while spring softening when high acceleration. About 30μW output power was observed at 0.03GRMS acceleration, and the maximum 90% conversion efficiency achieved at 0.01GRMS acceleration.

Commentary by Dr. Valentin Fuster
2018;():V001T08A004. doi:10.1115/ISPS-MIPE2018-8542.

Lubrication in nanometer-sliding gaps has attracted much interest along with the advance of processing technology. To clarify the lubrication phenomena in nanometer gaps, force measurement under accurate control of the gap between the sliding probe and sample surface is needed because the lubrication properties significantly depend on the gap size. In this paper, we aimed at realizing friction force microscopes that is capable of accurate control of sliding gap. A probe with an actuator that utilizes electrostatic force was proposed and its feasibility was demonstrated.

Commentary by Dr. Valentin Fuster
2018;():V001T08A005. doi:10.1115/ISPS-MIPE2018-8548.

In order to ensure the performance and durability of highly accurate mechanical systems, it is urgent to establish lubrication technology realized in minute gaps. It has been reported that the mechanical properties of lubricating oil in minute gaps narrowed down to nanometer order are completely different from those in the bulk state, and measurement of these phenomena are indispensable for lubrication design. In this research, in order to elucidate the temperature dependency of lubricant viscosity in nano gaps, we proposed laser heating of lubricating oil in highly sensitive viscosity measurement method developed in our previous study, which we called the fiber wobbling method (FWM). We succeeded in measuring temperature dependence of lubricating oil viscosity in nano gaps.

Commentary by Dr. Valentin Fuster

Advanced Simulation in Science and Engineering

2018;():V001T09A001. doi:10.1115/ISPS-MIPE2018-8512.

As automobile is exposed to continuous external forces such as road noise and engine vibration, it is necessary to evaluate vehicle components’ vibration durability at the initial design stage. Fatigue failure is one of the frequent failure mechanism occurred in mechanical components when cyclic loading is applied to subject. Fatigue analysis can be classified into two types; quasi-static fatigue analysis dynamic fatigue analysis considering structural resonance. As the tested bracket’s first natural frequency existed in the requirement spec for vibration test (10∼50 Hz) so dynamic fatigue analysis should be performed. In this study, vibration analysis was carried out in advance of fatigue analysis. Improving design based on the experiments is inefficient and takes a lot of time and money, so finite element model was constructed. From single components to assembly, modal test was performed and verified the finite element (FE) model within 10% error. Also, boundary conditions were determined using beam elements. After FE model construction, vibration analysis was performed using harmonic analysis. The cause of the failure was analyzed based on simulation results.

Commentary by Dr. Valentin Fuster
2018;():V001T09A002. doi:10.1115/ISPS-MIPE2018-8520.

Cable driven parallel robots (CDPRs) have been widely used in precision Industries. However, an error occurs in repetitive motion of the CDPR because of the elongation and recovery of cable. Also, it is difficult to apply the numerical cable model because of its complexity. In this paper, we use the frequency based H-RNN method for accurate kinematics. H-RNN predicted more accurately compared with LSTM and RNN algorithms.

Commentary by Dr. Valentin Fuster
2018;():V001T09A003. doi:10.1115/ISPS-MIPE2018-8522.

Conventional trains have used wheels while driving because of the friction between the rail and the wheels. However, the conventional train can’t drive fast. In contrast magnetic levitation (maglev) train can speed up to 600km/h. Because of driving so fast there are some vibrations on the car bodies. In this paper, we used multi-body dynamic analysis, ANSYS MAXWELL for determining magnetic forces and integrated with the MATLAB.

Commentary by Dr. Valentin Fuster
2018;():V001T09A004. doi:10.1115/ISPS-MIPE2018-8523.

Study on the steady blowing system using state-of-the-art of Computational Fluid Dynamics (CFD) technique based on an open domain CFD software, OpenFOAM[1], is performed to reduce vehicle aerodynamic drag. Realistic vehicle model, DrivAer[2], is used for the validation of current CFD technique. Both the aerodynamic drag coefficient and the surface pressure distributions were compared between current CFD and reference wind tunnel test. It was found that CFD method used in this study is reliable tool for the forecasting of the aerodynamic drag coefficient.

The influence of steady blowing from the sharp edge of the roof end is investigated based on DrivAer Estate back model. Parametric study was performed by changing blowing speed at the three different Reynolds number. It was shown that the steady blowing leads around 3% drag reduction by enhancing wake balance especially, reinforcing downwash flow from the roof.

Therefore it would be concluded that steady blowing is a useful device to reduce aerodynamic drag of automobile.

Topics: Automobiles
Commentary by Dr. Valentin Fuster
2018;():V001T09A005. doi:10.1115/ISPS-MIPE2018-8524.

Using Molecular Dynamics (MD) simulation, the current study determined the surface forces between iron oxide surfaces when immersed in methyl oleate. Condensed-phase Optimized Molecular Potentials for Atomistic Simulation Studies (COMPASS) force field was used to model the methyl oleate molecules. For the nano-confinement simulation, the iron oxide wall was modelled from its crystal structure. The nano-confinement simulation model was setup in a manner where the confined methyl oleate molecules were in contact with the bulk molecules surrounding each side of the iron oxide walls. Through the simulation, the load-separation gap profile was obtained by reducing the separation gap between the ferric oxide walls. When the separation gap was reduced from 2.75 nm to 1.88 nm, the load is shown to increase monotonically. Such increase in load bearing ability of the contact is observed to correspond to a more densely packed methyl oleate molecules, reflected by four well-formed layers across the separation gap. As the gap is dropped from 1.88 nm to 1.63 nm, the load instead reduces, indicating deteriorating load bearing ability of the contact. However, the load bearing ability of the contact is then shown to recover when the gap was further reduced till 1.38 nm. This oscillatory load trend is shown to be as a result of a layer of methyl oleate molecules being squeezed out of contact, corroborated by the density profile change where four well-formed layers were reduced to only three layers from 1.88 nm to 1.38 nm gap. This also indicates that the simulated contact exhibits structural forces, known as solvation forces. Thus, the MD simulation discussed in this study is demonstrated to be capable of providing a foundation to allow for a multi-scale simulation, integrating various force laws at different length scales, to study larger scale tribological contacts.

Commentary by Dr. Valentin Fuster
2018;():V001T09A006. doi:10.1115/ISPS-MIPE2018-8530.

This paper deals with the control performance improvement of the E-CVVT system using BLDC motor. Each element of the E-CVVT system is implemented by mathematical modeling. The response performance of the E-CVVT system is verified based on the camshaft motion, cam profile, BLDC motor and mathematical model of the controller. In order to confirm the speed change of the valve due to the rotation of the camshaft, a cam profile is used to express the up and down motion of the valve as a curve. To analyze the operating characteristics of the E-CVVT system, a BLDC motor is modeled using Simulink. The E-CVVT system controls the phase angle of the camshaft. When the E-CVVT system sets the target phase angle, the motor controller generates the optimal motor speed command. The response speed depends on the setting of each PID parameter, which changes the phase of the camshaft. Finally, we confirmed the improvement of the E-CVVT system response performance according to the change of the PID parameter.

Topics: Engines , Motors , Valves
Commentary by Dr. Valentin Fuster
2018;():V001T09A007. doi:10.1115/ISPS-MIPE2018-8538.

Newly formed metal surface is often unstable and becomes stable when it is terminated with another molecule, but the original color and properties may be diminished when it is covered with oxygen or gasses in atmosphere. Anti-copper-corrosion additives adsorb onto the surface of copper and it is used in order to prevent this phenomena and save copper’s color and properties [1]. There are few molecule findings about anti-copper-corrosion additive, however, and the mechanism of adsorbtion onto the surface of cupper and prevent corrosion. Recently, real-time instrumentation technique using Otto-SPR was proposed, and it is becoming possible to observe how additives adsorb onto the surface in molecular level [2].

Commentary by Dr. Valentin Fuster
2018;():V001T09A008. doi:10.1115/ISPS-MIPE2018-8543.

A thorough understanding of the dynamic behavior of friction modifier additives added to lubricating oil is crucial for improving the performance of boundary lubrication. However, such understanding is still lacking due to difficulty in measurements. In this study, we used coarse-grained (CG) molecular dynamics (MD) simulations to gain insight into the behavior of stearic acid additives physically adsorbed on corrugated or smooth hematite surfaces which were separated by lubricating oil of dodecane at a nanometric distance and sheared relative to each other. Compared with all-atom MD simulations, our CG MD simulations provided comparable accuracy and 40 times faster computational speed. The simulation results showed that, in contrast to the case of smooth solid surfaces, shear-induced desorption of stearic acid molecules and re-adsorption during rest occurred at the convex portions of the corrugated solid surfaces. This demonstrates that roughness of sliding surfaces largely influences the dynamic behavior of additives in lubricating oil.

Commentary by Dr. Valentin Fuster
2018;():V001T09A009. doi:10.1115/ISPS-MIPE2018-8551.

Polymer solution is used as lubricant in Tribological applications. Viscosity index improver is used to normalize temperature dependence of viscosity of the lubrication oil. Biological system such as synovial joint is a kind of polymer solution and strongly related to Tribology. Here we show our numerical simulation approach to investigate the dynamics of polymer solution. The numerical scheme is for simulating the dynamics of suspensions of Brownian particles, coupling molecular motion treated by Langevin equation and hydrodynamics treated by lattice Boltzmann method. The motion of polymer segments are simulated under shear condition in bulk, and in confined geometry. The viscosity change due to the change of polymer structure is found both in bulk and in confined geometry. In order to simulate realistic polymers, we modify each polymer segment as polar and non-polar particles. Point dipoles are added on the polar segments. Since the relative permittivity is very different in water and oil condition, the structure of the polymer is strongly affected by the distribution of the polar segments.

Commentary by Dr. Valentin Fuster
2018;():V001T09A010. doi:10.1115/ISPS-MIPE2018-8586.

This paper describes a predictive method for fault detection in the fail-safe system of autonomous vehicles based on the multi sliding mode observer. In order to detect faults in sensors, such as radar and acceleration sensors used for longitudinal control of the autonomous vehicles, the kinematic model-based sliding mode observer and a predictive algorithm have been used. The driving condition that the subject vehicle is driving with a preceding vehicle has been considered in this study. The relative acceleration has been reconstructed based on the sliding mode observer using relative displacement and velocity. Based on the reconstructed relative acceleration, the upper and lower limits of longitudinal acceleration for fault detection have been derived based on the stochastic analysis of the driver’s driving data. The measured longitudinal acceleration of the subject vehicle has been used to predict the relative states using the longitudinal kinematic model. The predicted relative states have been stored, and the stored states that represent the current states have been used to detect faults in the sensors. With regard to longitudinal acceleration, the multi sliding mode observer has been used to detect faults in the acceleration sensor. The predictive fault detection algorithm proposed in this study can detect faults in the environment sensors individually based on past sensor information. In order to obtain a reasonable performance evaluation, actual driving data and a 3D full vehicle model constructed in the Matlab/Simulink environment have been used in this study. The results of the performance evaluation show that the predictive fault detection algorithm was successfully able to detect faults in the sensors for longitudinal control individually.

Commentary by Dr. Valentin Fuster
2018;():V001T09A011. doi:10.1115/ISPS-MIPE2018-8587.

This paper describes an extended Kalman filter based object tracking algorithm for autonomous guided truck using 1-layer laser scanner. The 1-layer laser scanner has been used to obtain 2D cloud point data to detect the preceding object for tracking control. The object tracking algorithm proposed in this study consists of perception, decision, and control stages. In the perception stage, object’s information such as relative coordinate and yaw angle has been derived based on coordinate transformation, clustering, and state estimation algorithm using the obtained point data from laser scanner. In order to estimate object’s states such as coordinate and velocity, the extended Kalman filter has been used in this study. Based on the estimated states of the object, the desired path has been derived for calculation of steering angle. The simplified mathematical model of the truck has been derived to design optimal controller. The optimal controller designed in this study is based on the linear quadratic regulator for computing the optimal angle of steering module used for tracking. In order for reasonable performance evaluation, actual data from laser scanner and the derived mathematical model of truck have been used. The developed tracking algorithm and performance evaluation have been designed and conducted on Matlab/Simulink environment. Results of the performance evaluation show that the developed object tracking algorithm has been able to track the preceding object using 1-layer laser scanner.

Commentary by Dr. Valentin Fuster

Optical Storage and Optical Devices

2018;():V001T10A001. doi:10.1115/ISPS-MIPE2018-8517.

Mechaless LiDAR technology, which does not have a mechanical drive part, has been actively studied in order to increase the reliability of the LiDAR device at low cost and drive environment in order to more actively apply LiDAR technology to autonomous driving. Mechaless LiDAR technology, which has been mainly studied recently, includes 3D Flash LiDAR technology, MEMS mirror utilization method, and OPA (Optical Phased Array). However, these methods have not been developed rapidly as a key technology for achieving autonomous driving due to low stability of driving environment or remarkably low measurable distance and FOV (field of view) compared with mechanical LiDAR. In this study, we investigated the improvement of FOV by using a flux-deflecting liquid lens and a fisheye lens that can achieve fine spatial resolution through continuous voltage regulation. Based on the initial design results, it was examined that the FOV can be secured to 80 ° or more by utilizing a relatively simple fisheye lens composed of only spherical lenses.

Commentary by Dr. Valentin Fuster
2018;():V001T10A002. doi:10.1115/ISPS-MIPE2018-8518.

In this paper, phase quantitative measurements using digital holography (DH) with low-coherence light sources are presented. Compared with conventional laser-based DH, low-coherence light sources have advantages of better image quality, less speckle noise, and smaller system configurations. As a light source, we utilized light-emitting diode (LED) and quantum dot (QD) film. In particular, quantum dot film emits low-coherence lights with adjustable wavelength and high conversion efficiency, which has versatility for additional methods including dual-wavelength reconstruction. Experimental results verify the quality enhanced quantitative measurement of proposed methods compared with conventional systems.

Topics: Holography
Commentary by Dr. Valentin Fuster
2018;():V001T10A003. doi:10.1115/ISPS-MIPE2018-8584.

In this paper a low power all-digital clock and data recovery (ADCDR) with 1Mhz frequency has been proposed. The proposed circuit is designed for optical receiver circuit on the battery-less photovoltaic IoT (Internet of Things) tags. The conventional RF receiver has been replaced by the visible light optical receiver for battery-less IoT tags. With this proposed ADCDR a low voltage, low power consumption & tiny IoT tags can be fabricated. The proposed circuit achieve the maximum bandwidth of 1MHz, which is compatible with the commercial available LED and light sensor. The proposed circuit has been fabricated in TSMC 0.18um 1P6M standard CMOS process. Experimental results show that the power consumption of the optical receiver is approximately 5.58uW with a supply voltage of 1V and the data rate achieves 1Mbit/s. The lock time of the ADCDR is 0.893ms with 3.31ns RMS jitter period.

Commentary by Dr. Valentin Fuster

IoT and Reliability Technology

2018;():V001T13A001. doi:10.1115/ISPS-MIPE2018-8570.

In this paper a new on-chip 2nd generation solar energy harvesting DC-DC converter has been proposed for a battery-less Internet of Things (IoTs) Devices. The propose circuit is design to maximize the transfer efficiency and stability as well as enough high power supply to the back-end loads. Altogether the proposed circuit consists of a cross-coupled charge pump, a maximum power point tracking (MPPT) circuit, a timing control circuit and regulator. The range of input voltage is from 0.5V to 3V. Required boosted output voltage is in the range of 1V to 3.3V. The maximum transfer efficiency is more than 60% and the maximum throughout power is 200μW. A gated clock frequency modulation circuit has been designed and employed in the maximum power point tracking (MPPT) unit to lock the input resistance of the charge pump. In addition, to provide a stable voltage to the load a low dropout (LDO) regulator circuit is used. The experimental results show that the maximum power conversion efficiency (PCE) is 78% at 52μW input power condition.

Commentary by Dr. Valentin Fuster

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