Whole body 3D estimation of jumping motion using body-mounted sensor system is proposed. Inertial sensor board using 3D accelerometer, 3D gyroscope and 3D geomagnetic sensor is newly developed and twelve boards are mounted on upper body and lower body. The posture of the body is estimated using the orientation of sensors applying extended Kalman filter when the foot is on the ground, and trajectory of the body is calculated by the numerical integration of acceleration measured from the trunk during jumping. Contact sensors are attached under foot to classify the body motion into landing and jumping and to select the calculation method of body motion. To confirm the precision of the proposed method, the position of the trunk and joint angles estimated by the proposed method are compared with that measured by optical motion capture system. The experimental results show that the proposed method has successfully derived 3D motion of jumping motion toward forward, sideways and backward.

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In this study, we fabricated a triaxial force sensor for prevention of pressure ulcers by plaster casts. The size of the triaxial force sensor is 16×25×8 mm^3. We put this sensor into the plaster casts, and measure the contact force between the heel and the plaster casts. We measured the total force by adding X, Y, and Z axis force under the conditions of the heel height from 50 mm to 200 mm and the knee bending angle from 0 degree to 50 degree. We confirm that the minimum total force was 110 kPa at heel height of 50 mm and the knee bending angle of 20 degree.

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Currently, MRI-guided neurosurgical procedures are performed in an operating room with open MRI, and intraoperative MR images are provided with real time rich biological information. However, it is difficult to perform procedure in MRI gantry. So, patient is moved out of MRI gantry when performed procedure. The MRI-compatible robots and navigation system for performing procedure in MRI operating room are developed. For precise surgery, actuators which can operate precisely in the MRI room is required. This paper proposed a prototype of pneumatic stepping actuator for MRI-compatible actuator. MR-compatible is required for actuators used in the MRI operating room. The actuators was developing 3D printer and evaluated the performance of repeatability.

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A catheterization is one of the minimally invasive surgery. In the catheterization, X-ray fluoroscopy helps surgeons to track the point of a catheter tip, therefore they have to be exposed to radiation all the time. Catheterization requires adequate skills and experiences, and the technical gap among surgeons is huge. To solve it, the automatic system which guides a catheter to the target area is needed. In this paper, we propose the simple module device which inserts a catheter using friction wheel mechanism. This device can make a catheter rotate and translate in itself. It is designed to prepare simply and prevent a catheter from slipping by heparinized saline. The experimental result shows that the device has high positioning accuracy of a catheter.

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A sensorless flow rate measurement has been proposed to control a flow rate in a magnetically levitated centrifugal blood pump without any flow sensor. The proposed algorithm consists of a linear function of the flow rate and the ratio of rotational torque to rotational speed of the impeller. In the range between 0 and 10 L/min with a working fluid of water, the error of the estimated flow rate using directly measured torque was less than 0.51 L/min, which was about a half of the equivalent value using the torque estimated from motor power consumption. Using several working fluids whose viscosity ranged from 0.75 to 3.29 mPa・s, the viscosity was estimated with the error of less than 0.16 mPa・s, from the directly measured torque when the outlet was clamped. Estimated flow rate, compensated by the estimated viscosity, showed the error of less than 0.77 L/min in the range of up to 10 L/min.

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We have developed haptic sensing system including bidirectionality for the laparoscopic surgery. A forceps-type tactile sensor using sound reflection is developed for the sensing system. The sensor ensures safety in electricity for body tissue and can be sterilized and deterged. In this paper, a surgical simulation environment is assembled and experiment using the developed sensor is conducted for a phantom of the stomach wall with a 0-IIc type tumor (most popular early-stage gastric cancer) in that environment. Result shows that large sensor output is obtained for the lump due to the phantom tumor and the sensor has a potential to detect the lump in the laparoscopic surgery.

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In this work, we measured the bending moment using a grasping forceps with sensors. Grasping operations during the endoscopic surgery apply forces and moments to the grasped object. The forces and moments cause damage to the grasped object. Therefore, measurement of the forces and moments is necessary to prevent the damage by the over application. We have measured the forces by the grasping forceps with two MEMS (Micro Electro Mechanical Systems) triaxial force sensors and a potentiometer. In this paper, we measured the bending moment induced by rotating a rigid rod between the tips of the developed grasping forceps. Measured bending moment was linear to the rotation angle and 1.7 mN・m for 1° rotation.

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Although a kinesthetic illusion can be elicited by stimulating a tendon through vibration, many questions remain regarding the conditions of vibration necessary to elicit the kinesthetic illusion. The purpose of this study is to establish the conditions of vibration which are required in order to control the phenomenon of kinesthetic illusion. In order to do this, we develop an experiment system consisting of a vibration stimulator and a wrist angle measurement device. Moreover, we propose using the experiment system and the staircase method in order to measure the threshold above which the illusion will occur. Our preliminary experiment confirmed the effect of this system of measurement, with a threshold found to be at around 40 [m/s^2] with vibration stimuli of 70[Hz] and 80[Hz].

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Physician palpation is a useful medical examination, because it is non-invasive, quick and simple. However, to make an accurate diagnosis using palpation, physicians need long-time training and practice. Moreover, it is difficult for beginners to learn how to make a motion on palpation and what to feel at that time. Therefore, this study aims to clarify the relationship between the palpation motions and haptic sense, and to support beginners to improve the palpation skill. At first, models for palpation are designed. Each model has a hard lump made of silicone in soft polyurethane resin. The models are of seven types. The difference among them is the forms of lumps. Next, a measurement system for palpation motion is developed. The system has two cameras and a load cell. Subjects explore the models like conducting palpation, and then answer the lump forms. In experiments, palpation motion data of ten subjects are obtained by using the measurement system. The characteristics of the motion were extracted from the experiment data. And, it is confirmed that the instruction for the effective motions improves palpation skill.

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We propose a system to support the mastery of driving skills of the car by using the acoustic information. To investigate effects of the acoustic information, we made the simulator of a car with steering wheel, accelerator pedal and brake. The simulator provides the acoustic information to the driver according to the driving conditions. The experiments were performed in parallel parking by using the simulator. For lead of appropriate steering wheel operation, white noise according to the PI-controlled pan and sound level was output by two speakers. It was recognized that the value of steering wheel operation approached the target value by using acoustic information.

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We have conducted experiments of operating a force operating joystick to both sound stimulus and visual stimulus. Sound stimulus is white noise that sound level fluctuates periodically. Visual stimulus is the bar which performs vertical motion periodically. These two stimuli with phase shift are given to test subjects. During an experiment, biological signal IEMG and joystick operating force are measured. We demonstrated that there is no phase shift between IEMG signal and visual stimulus when the appropriate phase shift between sound stimulus and visual stimulus are given to test subjects.

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Line length perceptual characteristics have been studied from various viewpoints: for example, the person's initiative in the movements, and the sensations such as the proprioceptive sensations that return the physical states of joint rotations, the muscle activity sensations with extension and flexion, and the cutaneous sensations. However, in the existing works, there have been limited within specific aspects. Therefore, from the viewpoints of covering the above-described factors generally, two-dimensional line segment perceptual characteristics were examined by using a 2-D Cartesian coordinate liner actuator. The Line length perceptual characteristics shall be applied to line drawing presentation systems for visually impaired persons in the future.

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In virtual reality (VR) study, there are two ways active and passive touches to explore a virtual object with the tactile mouse. There is an issue "which is superior active or passive touch?" The active touch is to touch and perceive an object actively, while the passive touch is to touch and perceive a change of an object passively. The purpose of this study is to evaluate a perception precision in active and passive touches to clarify the best exploration method. This experiment is exploring the degree of leaning of the edge line using the tactile mouse in the virtual space. We develop a new tactile display called a palm tactile mouse and evaluate the perception precision using an angle difference-threshold and a judgment probability-function calculated by constant method of the psychophysical experiment. As a result, we confirmed that perception precision is the best when explore speed is 90 mm/s, and the active touch is not different from the passive touch.

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Since a robot plays a role in several situations such as public facilities and housework, it has to handle the various objects. In order to achieve the abovementioned handling, a free grasping is effective to obtain a rotational DOF of the grasped object by reducing grasping force. In this study, in order to realize the free grasping, we have developed two functions. One is the attitude control of a rod-shaped grasped object through the reduced grasping, which is a transient process for the free grasping. The other is detection of holes using a rod-shaped object grasped by the robot under the free grasping. In addition, in order to evaluate the abovementioned two functions, we have carried out an assembly task, in which these two functions are used to evaluate them.

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This paper deals with a visual warning system for accidental hazardous factors with a driving support system. Especially warning of the pedestrian who will try to cross the road behind the parked vehicle. The prediction is coming from the inductive database of the navigation system. Sometimes warnings are failed because the warning is based on the hazardous probabilities. Then the warning in the peripheral vision that is called "ambient warning", is paid a attention. In this experiments with driving visual simulator using driving game machine, ambient warning is effective to inform the driver of the frequent hazardous information with a little nuisance.

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In this paper, we propose the method to estimate the motion direction of walking based on brain wave activity. The signals of 11-channel as Electroencephalogram (EEG) of a motor area are measured to estimate the direction of a walking. After measuring the signals of 11-channel related to the motion of the lower limb, the several signal processing algorithm are applied for the signals. Specifically, we have used band pass filter to cut off the signal other than between 5-35[Hz], JADE as a form of Independent Component Analysis (ICA) and Multi-class Support Vector Machine (SVM) as a motion classifier. We performed the experiment that one subject sitting down on a bed with opened eyes images the motion of walking, standing and turning the left and right direction among interval of 30 seconds, respectively. As the result of applying our algorithm, the recognition rate within 50-60[%] was achieved. But, it is necessary to increase number of subject, to verify the algorithm and to raise the precision of the rate. The final target is to reveal the estimation method of motion direction of walking by means of several kinds of experiments.

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This paper proposes a new predictive control system using recurrent RBF networks (RRBFN) and Fuzzy rules. This system is constructed from two kinds of prediction systems and a Fuzzy control system. The prediction systems are constructed from a short-term prediction system and a long-term prediction system. In the short-term prediction system, a RRBFN is inputted the current state of a controlled object, and learns to output the next state of it. In the long-term prediction system, the RRBFN is inputted the state of a controlled object, that was predicted by the short-term prediction system, and predicts the next state of it. The long-term prediction system is repeated this operation n times, and predicts the state of the controlled object on time t+n. The Fuzzy control system controls the controlled object based on the prediction results of the long-term prediction system. We test the proposed method under an outfielder problem in order to investigate its efficiency.

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When we learn such complicated movements as sports and dances, we imitate the ideal movements in most cases. To learn these movements effectively, it is necessary to detect the movement to be improved from photos and videos and to reproduce the movements in corrected ways. It is also required for learners to evaluate their own learning achievements. To solve this problem, the authors have focused their attentions on the transmission of information instead of power and energy: the information-intensive concept can be achieved by introducing an active haptic scheme where users voluntarily moved their muscles, after accepting triggers from the actuators, and the concept was referred to as a restrained small-power based motion instruction in this paper. Under the novel concept, a prototype of a 2-link 1-DOF rotational elbow joint interface was developed for teaching extension-flexion operations of forearms. A potential of the novel instruction concept was confirmed from the viewpoint of motion reproducibility and necessary torques.

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An electromyogram signal is one of the commonly used input signals to control an electrical arm. Some estimation methods of the user's motion intention based on the electromyogram signals have been proposed in order to control electrical arms according to the user's motion intention. However, in the cases of above elbow amputees, the muscles which are used to generate the forearm and wrist motions are missing, and electromyogram signals of those muscles could not be measured. To control the forearm and wrist motions of an electrical arm for above elbow amputees, other input signals are necessary. In this paper, to control the forearm and wrist motions of an electrical arm, we estimate the target position of the hand based on the electroencephalogram signals, the shoulder and elbow angles.

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Robots are widely expected to be applied to work in strcken area and hazardous environment. In this paper, we propose a new robot system for Rough Terrain witch is consists of omni-directional mobile robot, wire and helikopter. We use the helikopter to put the top of the wire to the target, then wind up the wire to move the moblie robot to the target. This method is expected to work on the ground witch is broken off, or clamb the wall in a deep hole. We show how the robot moves in simulations by Open Dynamis Engine, optimize the movement of the moblie robot and the helikopter.

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In this paper, force sensor-less servo control technique for haptic interfaces using stochastic resonance is proposed. The haptic interface developed in this research consists of an AC servo motor with a ball screw. For estimation of applied force, Reaction Force Observer is employed. Since the ball screw structure has high viscosity, response of the force estimation is not suitable for practical industrial application. In this paper, to improve the system responsiveness, servo control system with stochastic resonance is proposed. Finally, several experiments show the effectiveness of the stochastic resonance.

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This paper presents a numerical analysis of adhesion force-displacement relationship due to meniscus formation between a sphere and flat considering the elastic deformation of the contacting surfaces. Analytical model and basic equations for numerical analysis are explained first. Meniscus contact characteristics calculated for 2 mm radius glass sphere on a magnetic disk coated with submonolayer mobile lubricant and 20 nm radius asperity on bonded lubricant layer with a low elasticity are presented. It was found that the sphere-flat contact with submonolayer liquid meniscus shows DMT-like behavior to JKR-like one as the lubricant thickness is decreased to 0.4-0.35 nm. This method can be used for rigorous analysis of various meniscus adhesion contact problems.

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Recovery or replenishment of lubricant holes caused by sliding is important for thin-film lubrication. However, due to the difficulty of measurement, the recovery process of molecularly thin lubricant films has not been fully clarified yet. In this report, we tried to observe the recovery process of monolayer thick films by using two-stage imaging ellipsometric microscope. Using the developed microscope, the recovery process of the monolayer films with different bonding ratio was investigated.

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This paper describes effects of characteristics of liquid on droplet transportation of EWOD (Electrowetting on dielectric) microfluidic devices. EWOD is a technology for manipulating droplets discretely by controlling the surface wettability electrically. Pure water, saline (0.9%, 5%, 10%), ethanol and silicone oil (1cSt) were prepared as transported liquid and effects of physical properties of the liquid on the droplet transportation were investigated experimentally. The results show that optimal volume of the droplet depends on contact angle of the liquid, and that electrical conductivity, dielectric constant and initial contact angle of the liquid have a great effect on the transport performance.

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We fabricate titania layer of Dye-sensitized Solar Cell by electro-spray. When high voltage is applied to a tube filled with conductive liquid, electro-spray takes place. We have demonstrated that conversion efficiency of fabricated cell is higher than conventional method. When the distance of the target from the nozzle tip is large, sprayed area is large. Moreover, deposition time is increased. To prevent this problem, dielectric material is installed between syringe and target. Therefore, spray area uses the electric charge which particles have, and is controlled. We have demonstrated that the focusing property is possible in this experiment.

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This paper describes water-repellency and drag forces of hydrophobic wire legs for water-walking robots inspired by a water strider. Recently, many researchers developed bio-inspired water-walking robots. However, the supporting legs of these robots are inferior to those of water striders in water repellency. In this study, helical grooves with various depths were fabricated on the surface of a brass wire using femtosecond laser machining to increase water repellency. Effects of the grooves on contact angles and drag forces were investigated. The experimental results showed that the wire with deep grooves exhibits high water repellency. The drag force acting on the leg was found to obey the drag equation when the reference area was determined considering a dimple and a bump of the surface of water.

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This paper describes effects of viscous liquid on adhesive characteristics of sole pads for insect-inspired wall-climbing robots. Ants can walk on the smooth vertical surfaces using an adhesive organ and secreted viscous liquid. We fabricated two kinds of adhesive pads inspired by the adhesive organ of ants. Pure water and silicone oil of kinetic viscosity 1000 mm^2/s were provided to the pads, and normal adhesive forces between the pad and a glass surface were measured. The experimental results show that the pad provided with the silicone oil generates higher adhesive force than the pad with water. The adhesive force of the silicone oil remains constant regardless of the pad materials and amount of the oil, and increases with increasing pull-off velocity.

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In this study, we have developed a microfluidic device integrated with a microfluidic probe to clarify a differentiation mechanism of pluripotent stem cells. It is difficult to evaluate efficacy of chemical reagents for the differentiation using a conventional method because cells cultured in culture dishes are exposed to the reagents homogenously. Here, we propose a novel culture method which enables exposing cells to different chemical condition by location. The device has been evaluated by a computer simulation using FEM, and a flow control experiment. A control of chemical stimulation from single cell level to tissue level in a microspace can be possible by regulating flow ratio and channel size of the microfluidic probe. By using the device, staining of single cell level in a microspace succeeded.

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We experimentally demonstrate the conditions where rare-gas cluster ion dissociates depending on the elastic response at the collision. Cluster ion consisting of thousands of argon atoms collide with the five kinds of metals at an incident energy per atom of less than 10 eV. The prominent ions in the mass spectra detected are dissociated ions such as dimer (Ar_2^+) or trimer ions (Ar_3^+). The branching ratio of the ion yield Ar_2^+/ΣAr_n^+(n ≥ 2), representing the dissociation rate, is significantly different by the metals. As a result, we found the dissociation rate of cluster ion is linearly increased with the impulsive stress acting on the contact area between the cluster ion and the metal surface. In addition, we discussed the possibility the result is applied to a new evaluation method of material strength.

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Photocatalyst deodorant equipment having discharging capability, which consist of electric discharging electrode and photo and ozonolysis catalyst supports with wide range of varying amount of catalyst, needs to be designed for low-pressure loss and thin shape in order to set it into air conditioner filter. The aim of this study is to carry out optimal designing of photocatalyst deodorant equipment by taking into account of the effect of filter shape, ozonolysis performance, gas species, variation of the amount of catalyst and ambient environment. Finally, prediction formulas for optimal pressure loss and permeability of object gases were proposed to optimize the design of photocatalyst deodorant equipment.

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We developed a method for estimation of the excitation force of a scroll compressor for air-conditioning systems. The method is based on elastic support method using the measured acceleration response and transfer function of the supporting system. The amplitude and phase of excitation forces were estimated by solving an inverse dynamical problem that used as input the acceleration measured by accelerometers placed on the scroll compressor. The results obtained by the method agreed with the excitation force measured directly by using load cell.

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Electromagnetic valve for controlling the refrigerant flow is attached to pipe in air conditioning units. Excitation force is generated in the pipe when electromagnetic valve opens and the refrigerant flows. Focusing on this excitation force, we carried out the experiment using refrigerant circulation system. On the other hand, pressure and the flow velocity in the pipe are calculated by fluid analysis. After that, using the pressure and the velocity, we calculated excitation force according to the momentum principle. We found that calculation results both excitation force and displacement of pipe agreed well with experimental results.

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Pan temperature sensing system for Induction cooktop with -10〜+14℃ accuracy which consists of a thermopile, an optical sensor which rectify the thermopile output based on the rate of infrared emission of a pan, and a thermistor which supress the deviation of thermopile output caused by heat disturbance, was developed.

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In this study, we prepared two types of PFPE lubricants (D-4OH and DDOH) with different end-groups of molecule. The D-4OH has two endgroups at both side of mainchain. On the other hand, the DDOH has one engroup at ingle side of mainchain. We coated the composite lubricant film by these lubricants on magnetic disks. First, we measured the friction force and the adhesion force on the disks with different lubricant thicknesses of D-4OH and DDOH by pin-on-disk test. Next, we measured these properties on the composite film and compared to these. We found that the adhesion force of D-4OH was lower than that of DDOH, and the friction coefficient of DDOH was lower than that of D-4OH. Composite lubricant film showed lowest the friction force in these lubricant films.

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In this study, we prepared two types of PFPE lubricants (D-4OH and DDOH) with different end-groups. These lubricants have the same backbone, but D-4OH has two end-groups at both side of main chain and DDOH has a end-group at single side of main chain. The ultra-thin composite lubricant consisted by these lubricants were coated on magnetic disks. We studied the clearance between head and disk surface and the slider wear after touch-down cycles on the lubricant film with different bonding(as dip/UV/UV-rinse) and the D-4OH/DDOH composite lubricant film. As a result, we found that the UV-rinsed lubricant film showed the widest clearance in the lubricant film with three kinds of bonding and the D-4OH/DDOH composite lubricant film showed the possibility to reduce the slider wear.

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Slider flying height has been reduced to less than 2 nm to increase the recording density of hard disk drives (HDDs). However, it is demanded that the flying height should be reduced more. On the other hand, the helium-filled HDD was proposed to resolve the positioning error and reduce the electricity consumption. In the helium-filled HDD, the wear properties of slider surface covered with diamond like carbon(DLC) may be different from the wear properties in air, because it has no oxygen. In this paper, we investigate wear properties of sliders as a function of relative amount of gases (water, Vertrel-XF, and ethanol) in atmospheric air and nitrogen.

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Vibration characteristics of a head slider in hard disk drives in near-contact and contact regimes becomes important because head-disk spacing must be decreased to less than 1 nm in order to increase recording density. This study elucidates head-disk interfacial (HDI) force based on rough surface adhesion contact models. Total HDI force including air-bearing force and suspension load due to spacing variation and resonance frequency of head slider at a given equilibrium spacing are evaluated for five different adhesion contact models. It was found that the experimental vibration characteristics can be explained well by asperity meniscus contact model. Two stable contact sliding conditions for contact recording are discussed. The stable sliding condition at a large separation is recommended from aspect of reducing head wear.

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Recording media with grooves such as discrete track media (DTM) and bit-patterned media (BPM) are considered to be some of the most promising media for achieving ultrahigh track densities. It is becoming increasingly important to analyze the static and dynamic characteristics of flying head sliders over DTM/BPM using the molecular gas-film lubrication (MGL) equation considering surface interactions. In this paper, we established an analysis method of Lennard-Jones interaction pressures acting between slider and a disk with two-dimensional distribution of material properties by using Fourier series expansion. The characteristics of the interaction pressures are quantitatively clarified.

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A new type of flying head slider mechanisms whose air bearing surface (ABS) or disk surface has local temperature distributions such as thermal fly-height control (TFC) and heat assisted magnetic recording (HAMR) have been proposed in order to increase the recording density. Moreover, recently, He-enclosed HDDs have been researched and developed to achieve high performance, because Helium has smaller windage loss and higher heat conductivity than air. Thus, it is becoming increasingly important to analyze the flying characteristics of head sliders over a running disk using the thermo-molecular gas-film lubrication (t-MGL) equation. In this paper, we numerically calculated the static lubrication characteristics for Air/He as working fluid. We also calculated the flying characteristics for various sliders.

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With ultraviolet (UV) irradiation through a photomask, nanometer-thick patterned perfluoropolyether (PFPE) films were successfully formed on magnetic disks. Such patterned films feature three-dimensional and functional distributions. The effect of pattern linewidth on friction properties was investigated by using a pin-on-disk friction tester. The friction force decreased with decreasing pattern linewidth. As the pattern linewidth decreased to 0.5 μm, the lowest friction force were observed, even as compared with non- and fully-UV-irradiated films. The similar trend was obtained in our previous experiments of film depletion as a function of pattern linewidth. This indicates that fine patterning is an effective way to improve the tribological properties of nanometer-thick lubricant films.

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In the head-disk interface (HDI) of a hard disk drive (HDD), the effects of lubricant deformation on the flying characteristics of a head slider increase as the flying height decreases. Therefore, it is very important to investigate the deformation and flow characteristics of lubricant on a recording disk. In particular, in heat-assisted magnetic recording (HAMR), laser heating of the lubricant induces surface tension distribution and evaporation of lubricant, which may cause deformation of the lubricant film. In this paper, flow characteristics of liquid nano-film of perfluoropolyether (PFPE) film on solid substrate is investigated experimentally. Using the modified Boltzmann-Matano method, diffusion coefficients of liquid nano-step are calculated. In addition, thicknesses of mobile layer and bonded layer of PFPE are measured.

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In Hard Disk Drives (HDDs), carriage vibration in low frequency due to an air flow caused by disk rotation is one of the factors that deteriorate the head positioning accuracy. Reduction of the disturbance is necessary for increasing capacities of HDDs. We proposed a new control strategy using a dual stage actuator mechanism and an additional electromagnetic actuator which provides a rotating stiffness to a carriage and suppresses the flow-induced carriage vibration. We measured a flow-induced carriage vibration when the additional actuator was working and carried out simulations of head positioning errors. It was confirmed that head positioning errors by flow-induced carriage vibration was reduced more than 30% compared with a dual stage actuator system.

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This paper proposed a HDD seeking acoustic analysis method by vibro-acoustics simulation with component-mode synthesis method and verified by comparing simulation results with experiments. Acoustics portion in the developed model is defined as a set of acoustic transfer functions from HDD surface velocity to sound pressure for each component-mode. The component-mode is calculated with the finite element method and the acoustics model is calculated with the boundary element method, and a mode shape of the component-mode is translated into a sound source in the boundary element method. Simulation results were verified by using experimental results of seeking acoustics with a 2.5-inch drive. Sound pressures given by simulation matched well with experiments and the required number of component-modes for acoustics simulation stayed within one for dynamic simulation.

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We proposed an actuator called a multi-layer coil actuator that attenuates an out-of-plane mode. The proposed actuator has film coil attached on VCM coil one above the other. Direction of pattern on the film coil above VCM coil is same as VCM coil, while that below VCM coil is opposite. Film coil doesn't generate rotational moment, but torsion moment. The ratio of the current for the film coil can be changed to attenuate an out-of-plane mode. We constructed the multi-layer coil actuator, and measured the frequency response from the current of the two coils to head displacement by different ratios of current of film coil. The effectiveness of the proposed actuator in reducing excitation of the coil torsion mode was demonstrated through experiment.

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We propose a method for predicting a slider jump boundary, which is key to evaluate op-shock resistance of 2.5" hard disk drives. This method can easily predict a slider jump boundary by using the measured frequency response function (FRF). First, the time history shock responses of a disk and mount-plate are calculated by using the convolution integral with the measured FRFs. Then, the gram-load change is calculated by using a low-degree-of-freedom model with these time history shock responses. Finally, the slider jump boundary is determined when the gram-load, which is the summation of the initial gram-load and gram-load change, becomes 0. This method cannot be used for the contact, but the calculated slider jump boundary of the shock input in a short duration, such as 0.5 ms in which the effect of contact is small, is close to the measured shock resistance.

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This paper describes the experimental study on swing response of fluid film bearing spindle for Hard Disk Drives (HDDs). The FDBs are widely used as rotating shaft support elements for HDD spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for recording device such as laptop PCs, video cameras, car navigation systems. Hence, the rotating shaft contacts the bearing from disturbance, it causes of data loss. In order to avoid the problems, it is extremely important to know how the spindle moves against the large impact on HDDs experimentally. However, as far as the authors know, there are few experimental studies treating the swing response. In this paper, firstly, we propose a new test rig and test method for swing response of HDD spindle. Then we conduct the swing test on spindle for 2.5"HDD and show the experimental results of maximum displacement of disk and swing response waveforms.

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In electronic device, conductive adhesive is widely used to connect devices electrically and mechanically. Usually, the connection area has Au plating, however, it costs too much. Therefore, we studied using conductive adhesive without Au plating. In this case, the main problem is corrosion at the interface between conductive adhesive and stainless steel, and it causes insulation problem at the interface. The insulation takes place depending on time. So, if the interface has enough life until insulation, it is not serious problem. In this paper, we studied life of the interface using Highly Accelerated Temperature and Humidity Stress Test (HAST) chamber. The life was described by water vapor pressure Vp, and it decreased in proportion to the 4.307^<th> power of Vp. And HAST results showed that the interface without Au plating had enough life in actual use.

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This paper describes the robust optimum design considering dimensional tolerances for hydrodynamic air bearings of small size hard disk drives (HDDs). Hydrodynamic bearings for HDD spindle motors are generally manufactured by mass production processes which will eventually require reduction of production costs. Consequently, the hydrodynamic bearings are demanded to be easily manufactured and expected to have an insensitive design with low variability of bearing characteristics due to manufacturing errors. In this paper, the bearing characteristics are calculated considering dimensional tolerance using optimum design combined with statistical method in which the dimensional tolerance is assumed to distribute according to the Gaussian distribution. The bearing characteristics are estimated by expectation and standard deviation, and then Pareto solutions are obtained using the multi-objective genetic algorithm.

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In Electrophotographic copiers and printers, reducing the amount of beam spot misregistrations is one of the most important issues of reali zing high quality images. To solve this issue, it is necessary to clarify the mechanisms of generating the misregistrations, to find vibration parts of high co rrelation with the misregistrations and to to ke measures to the parts. In this study, in order t o clarify the mechanisms of the misregistrations, a new measurement method which i s available to get the a mount of bea m spot misregistrations and the vi bration of the op tical devices simultaneously and a data ext raction method of characteristics of couples of beam spot misregistrations and the vibrations are developed. Using these methods, it is possible to estimate the parts of vibration that cause misregistrations mainly and to estimate the tendency of the transfer function which is synthesized from the extracted characteristics. Also, these methods were verified using experimental devices.

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In Electrophotographic copiers and printers, for high image quality it is important to reduce vibration which affects optical systems. To confirm the effect of vibration reduction measures without trial machines, we have developed a numerical analysis method which is coupled mechanism analysis, structural analysis and ray tracing analysis. Using this method, it has become possible to evaluate numerically the dynamic behavior of misregistrations caused by optical parts vibration by vibromotive forces in drive systems and vibration characteristics of main frame, several units and another parts. Experiments for validation of the analysis method also have been done and it is confirmed that the estimated amount of misregistrations were almost the same as that of the experimental results.

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