This paper describes an investigation of fundamental characterization of a contact stimulus by diapers. Contact stimulus is a kind of mechanical stimulus like contact force or friction. A sensor for measuring the contact stimulus is fabricated. The polyvinylidene fluoride (PVDF) film, which is a kind of piezoelectric material, and a strain gauge are used as the sensor parts. In order to investigate relationship between the contact stimulus and the sensor outputs, a machine which can give rise to the contact stimulus between the sensor and diapers by rotating the sensor is developed. By using this machine, friction between the sensor and a diaper is measured. A parameter calculated from the PVDF film outputs is proposed for evaluating friction. It was confirmed that there is a possibility to evaluate friction of diaper aginst the sensor by the proposed parameter.

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◆歴史は繰り返す ex.1 30年前、空力振動はHDDの深刻な問題であった -その後、小径化が進み、それほど深刻ではなくなった -しかし、高TPI化・高回転化が進み、小径でも再び深刻な問題に ex.2 20年前デュアルアクチュエータ向けに加速度FF技術を開発した -その後シングル、回転アクチュエータで必要なくなった -しかし、高TPIイし高速化が進み、再び加速度FFが世界標準に ◆"Failure is the mother of success" "Curiosity is the mother of engineering"エンジニアは失敗経験により成長◆ひとつの技術領域に30年・・・ -要素技術は相対的なものであるという認識 -ベテランの方が柔軟な発想ができる? ex. spindle motor ◆HDD技術は、深掘りという点では他の追随を許さない -HDDエンジニアは、希有な経験のできた人たち -他分野へ応用しても、きっと良い成果が得られる

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The head positioning accuracy of the hard disk drive should be improved to meet today's increasing performance demands. Vibration suppression of the arm in the hard disk drive is very important to enhance the servo bandwidth of the head positioning system. In this study, the smart structure is introduced into the hard disk drive to suppress the vibration. It has been expected that technology of smart structure will contribute to the development of small and light-weight mechatronics devices with the required performance. First, modeling of the system is conducted with finite element method and modal analysis. Next, the actuator location and the control system are simultaneously optimized using genetic algorithm. Vibration control effect has been evaluated by some simulations. Finally, the optimal sensor location is investigated by evaluating uncertainty of perturbed system.

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One of the major contributors to head positioning error is carriage vibration in low frequency due to the air flow caused by the disk rotation. We experimentally studied the reduction of the flow-induced carriage vibration using linear protuberance structure by putting wires on the carriage arms. This study was carried out using 2.5 inch HDDs which has high rotational speed of 10krpm. We measured the position error signal and compared with the conventional carriage arms. From the experimental result, the linear protuberance structure we proposed is effective to reduce the carriage vibration. We confirmed that our new structure decreased the non-repeatable position error by 8.5% for outer positioning.

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This paper reports on the shock evaluation method for a magnetic Hard-Disk Drive (HDD). High-speed cameras are typically used for shock evaluations of HDD's. The cameras can observe the slider lift-off and vibration of arms and disks. However recently, due to decreasing flying height, slider-disk contact often occurs by small slider vibration which can not be observed by high-speed camera. Meanwhile, capacitance measurement between the slider and disk is useful for evaluating the slider behavior in HDD operational shock tests. We established the evaluation method for HDD shock mechanism by high-speed camera observation and slider-disk capacitance measurement at the same time.

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Fluid film bearings are widely used for HDD spindle motors due to high accuracy requirements. The study related to fluid film bearings has been actively conducted by many researchers, where recently optimum design of fluid film bearings which maximizes the stiffness and minimizes the friction torque is studied. On the other hand, it is estimated that because of its miniaturized design, even with a slight manufacturing error, the intended performance of the optimum design decreases. Therefore, it is essential to consider the dimension tolerance for optimum design of fluid film bearings. In this paper, the influence of bearing characteristic values upon the occurrence of the dimension tolerance by stochastic method with a 2.5"HDD spindle motors using fluid film bearing is conducted. As a result, the random variables are applied to high-influenced design variables for bearing performance, and optimum design with consideration of dimension tolerance is clarified.

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A 3-phase electrostatic stepper micromotor was developed. To improve its performance for actual use, we have conducted numerical simulation to optimize the design. An improved simulation method is needed for calculation of various cases. To conduct circuit simulation of this micromotor, its structure is simplified, and a function for computing the force excited by the electrostatic field is added to the circuit simulator. We considered simplification method to achieve a reasonably accurate simulation.

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There are many people who cannot stand up on them own and need help moving from sitting posture to sitting posture. However many of them want to do it without assistants. Therefore, we developed a robot that assists them to transfer. People assisted by the robot sometime express about their physical burden. Especially, they complain of armpit and abdomen pain. In order to decrease these pains, it is important to find that how the force acts on their body. In this paper, we propose the method of evaluating physical burden. Further more, using a proto type, we demonstrate experimental results, which are compared with analytical ones.

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Estimation method of three-dimensional (3D) motion of upper limb, trunk and shoulder torque during pitching using body-mounted sensor is discussed The body-mounted sensor is composed of 3D accelerometer and 3D gyroscope with different dynamic range and is attached on upper arm, forearm and chest. The 3D trajectory is obtained by numerical integration of acceleration and angular velocity. Initial posture of the subject such as setup position is derived by performing four pre-determined movements^ rotation of whole body around vertical axis, flexion and extension of elbow, adduction and abduction of shoulder and keeping upper limb on suspending. Shoulder joint torque is estimated as internal/external torque, adduction/abduction torque and varus/valgus torque. Three subjects participated in the pitching experiment and the experimental results show that estimated 3D trajectory is highly correlated with that from motion capture system and shoulder torque is reasonably estimated.

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Currently, MRI is used not only for diagnosis but also for intraoperative surgical treatment. The surgeon determines the position of the disease region by comparing the MR image and the patient's condition during the operation. Therefore, the predicted spatial position of the diseased part is based mainly on the surgeon's knowledge and experience, and surgeons do not fully utilize the information obtained from the MR image. In order to provide intuitive visualization of MR image for surgery navigation, we developed LCD slice image overlay navigation system that augments MR image onto patient's body. Phantom experiments have been performed to evaluate image overlay accuracy of the system. The result of a target registration error of 1.4 ± 0.6 mm. It has been shown that the proposed system can function as a new vision system for open-type MRI systems and assist surgeons in minimally invasive surgeries.

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This paper reports on the impact of setup of a ventricular assist system (VAS) and the VAS surroundings on measurement of electromagnetic noise from VAS, based on CISPR pub.11. We measured four types of electromagnetic noise. Type 1 consisted only of the VAS. Type 2 was the VAS and a human subject who gripped the VAS actuator. Type 3 was the VAS and a copper rod that connected to ground and the actuator. Type 4 was the VAS and a human who gripped the actuator and directly touched the copper rod. When the measurement frequency was 30 MHz, the electromagnetic noise of Type 2 increased by 1.6 dBμV/m, compared to the electromagnetic noise of Type 1. Electromagnetic noise of Type 3 and Type 4 also increased, by 5.2 dBμV/m and 2.6 dBμV/m, respectively, compared to electromagnetic noise of Typel. Based on these results, the setup of a VAS and its surroundings were confirmed to affect the amounts of electromagnetic noise measured.

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Observing real time deformation at the atomic-scale has been a great challenge because of the difficulty in both formation and observation of nano-contacts. We have combined nano-scale handling capabilities of MEMS technology with the supreme observation ability of TEM and developed a MEMS-in-TEM experimental setup. Our MEMS device had Ag tips controlled by electrostatic actuators. Opposing tips were brought into contact using the actuator. After achieving the contact, Ag-coated opposing tip was actuated in lateral direction while maintaining the contact. We succeeded in observing the deformation of the frictional interface at the boundaries of the gliding grains. Furthermore, we have observed that the interface was reorganized because of the dislocated strain.

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Since the discovery of carbon nanotubes(CNTs), the remarkable mechanical properties such as high tensile strength, high flexibility, high heat conductance have attracted many interests. And the synthesis of high quality CNTs using various methods have studied. Kusunoki et al. have reported that CNTs with high-density and well-alignment are formed vertically on a silicon carbide substrate. CNTs on SiC substrate could be used for tribomaterial with high adherence because each CNT covalently bonds with the SiC substrate. Thus, we have studied about interfacial strength of CNT films made by surface decomposition of SiC by using atomic force microscopy. And considering the non linear bending theory on bending (or moment at the interface of CNT films), the wear mechanism was discussed.

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Conventional ellipsometric microscopes have low resolution because the oblique imaging plane to an optical axis decreases the focused area when high resolution objective lenses are used. In this paper, we represent a new imaging method. Once the film is formed in space by the first optical system and observed by the second imaging system. This enables that we place the imaging plane vertical to the optical axis and expand the focused area. Using this method, we achieved a lateral resolution of 0.78 μm and a focused area of 115 μm. We also successfully visualized a liquid nano-thick film sheared by an optical fiber probe.

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In order to reduce collision noise generated between a paper and rollers, we have verified the effect of the type of rollers and the contact locations on paper behavior and radiated sound by experiments and simulations. As a result, paper behavior and radiated sound vary according to the type of rollers and the angle of approach. Also, radiated sound of a paper correlated with the acceleration of the paper when it collided with the nip between rollers.

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In the Paper handling machine such as ATM, a well-known method of isolating paper sheets is to arrange a feed roller nested inside a gate roller. In this method, friction force during paper passing the nest affects the performance of isolation. Therefore, estimating the quantitative friction force can estimate isolation performance. In this paper, we estimate the contact forces of static and dynamic paper deformation, by using RecurDyn. And we survey the affection of accumulated papers.

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Currently, equipments using paper feeding mechanism such as copy-machine and printer are required higher paper feeding velocity. It is necessary to reveal the impact of paper feeding velocity on the characteristics of paper feeding mechanism. First, high speed paper feeding experiment was performed. And the characteristics of paper feeding mechanism dependences on paper feeding velocity were verified. Next, the effects of rubber viscoelasticity, dynamic friction coefficient of rubber dependences on slipping velocity and dynamic friction coefficient of paper dependences on slipping velocity were shown with experiments and two dimensional analyses. It is found that the characteristics of paper feeding mechanism dependences on paper feeding velocity are caused by dynamic friction coefficient of paper dependences on slipping velocity.

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Applying micro spray of electrostatic inkjet to precision film coating was examined experimentally. Using a single nozzle, high quality coating was demonstrated by the authors elsewhere. A critical issue, however, lies in terms of productivity; the amount of liquid jetted from a nozzle was too small to obtain sufficiently high coating speed. To overcome the situation, a possibility of a multi-nozzle was tried in this report. The liquid was dilute dispersion of photo-sensitive pigment. As results, from seven nozzles of stainless steel multi-nozzle, jetting direction was fanned out toward the opposite plate electrode. By clogging the both end nozzles and making them as electrodes, the direction was remedied and parallel jets were obtained. According to the increment of applied voltage, jetting mode was varied from dripping mode to cone-jet mode. Although the variation of jetting mode was qualitatively the same as that of a single nozzle, the higher voltage was required for a multi-nozzle. Furthermore, the mode change and uniform distribution of droplets always started from the end nozzles. Again, high voltage was required to alleviate the fluctuation of the droplet size distribution. From simple line-coating experiments suggested that the multi-nozzle with dummy electrodes at high applying voltage could jet well-oriented fine and uniform droplets to acquire quality film coating.

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Long flexible materials such as paper, optical film and metallic thin film are called web, which are made by Roll to Roll production system. In this production system web are transported under tension by a lot of rollers. High performance films such as fuel cell, printed electronics and solar cell are also made by Roll to Roll production system. So it's issue in the manufacturing field to improve productivity and prevent defects such as slippage and wrinkle. Today, engineers hope web is more thin to improve performance and wider to produce efficiently. However, web is occurred wrinkles on the roller easily due to such change although transported under very low tension. So engineers used concaved roller to prevent wrinkle. But there are very few papers written about preventing mechanism and limit of effect with concaved roller. This paper aims to clear preventing effect for wrinkle by concaved roller experimentally. We experimented wrinkle generation by four test rollers: cylindrical roller, it with micro-groove, concaved roller and it with micro-groove, and clear relation between concaved roller and wrinkle generation to compare each experimental results.

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Wound rolls are often subjected to a homogeneous temperature change. This paper presents the results of internal radial stress measurement under the temperature change. In addition, Film properties such as Young's modulus and thermal expansion coefficient are measured for numerical analysis. Results from the thermal stress analysis are compared to the measurements of radial stress data for two materials: PET and PP. The result described different change between PET and PP. Moreover, measured material properties are incorporated into a calculation model which provides good agreement to the result of radial stress measurement.

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Flat belts are used widely in ATMs, automated ticket machines, mail sorting machines, color printers and copiers. In color printers, rollers and flat belts are used to transfer toner images. Belt skew (side walk) in the belt lateral direction affects serious influence on the printer image quality. In this research, in order to study characteristics of the belt skew under arbitrary roller tilt conditions, an experimental apparatus with two rollers and a belt was made. At the same time, simulation using FEM (Finite Element Method) software was performed and both results are compared. Furthermore, a wrinkle occurring process of belt is simulated.

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