A flexible support mechanism for a hard-disk drive (HDD) was devised, prototyped, and evaluated. It was shown that when a HDD is supported flexibly by, the vibration disturbance to the HDD caused by becomes lower frequency. Moreover, the resonance frequency of the HDD with a flexible support mechanism is lower than the HDD itself. The flexible support mechanism has a high interception rate to in regards to the disturbance inputted into the HDD. It is therefore possible to reduce the positioning error of the HDD by applying such a flexible support structure. The data-transfer rate of the HDD decreases when the head-positioning error becomes large, because a longer read/write time is required. Since the head-positioning error can be reduced by applying the flexible support mechanism, degradation of the read/write performance by vibration disturbance can be prevented. In addition, a HDD with the prototyped flexible support mechanism showed 2.0-time-higher power-proof than HDD itself.

View full abstract

A piggyback actuator indispensables for a spin-stand system that evaluates high density magnetic recording, because magnetic recording head must follow a very narrow track precisely on a high speed rotating disk for a read-back signal evaluation. The authors had designed the Nano-Motion Actuator of 10nm spec, which was applied for the spin-stand. However, the actuator can not apply for a pre-write servo disk and a discrete disk, because when these types of disks are clamped on an air-spindle, eccentricity between the disk center and the center axis of the air-spindle occurs. Since the error of the eccentricity reaches to one handled micron meter, a new Nano-Motion Actuator of large work distance is required.

View full abstract

This paper describes a novel magnetic head positioning mechanism, which uses two micro-actuators in order to change contact forces acting on contact pads. Differential of drag forces acting on the two contact pads swings a slider, and this swing motion is utilized as head positioning. In addition, this mechanism can compensate skew angle of a magnetic head against recording tracks. First, it was showed that low rotational stiffness is needed for self-slignment of skew angle. Next, simulation with the analysis model was performed on following and seeking motion, which showed that this mechanism can compensate skew angle automatically, but its seek time is longer than that of conventional head positioning mechanism. Last, a scale model which had two actuated contact pads was experimentally built, and it was shown that the scale model can be actuated by contact force. Additionally, the linearity of swing anglewith respect to the input voltage and ability of actuation with only a single actuated contact pad were shown experimentally.

View full abstract

The mechanism of scratch induced demagnetization is studied for perpendicular magnetic recording (PMR) disk media. The scratches, which may occur on the disk surface during the head/disk contact, caused demagnetization related to read/write error. The relationship between scratch depth and demagnetization were investigated by the scratch test which is quantitative scratch making technique and the AFM/MFM observation. It is found that demagnetization is not due to flaking off of the disk medium, but deformation in the disk inner medium. Moreover, the disk deformations under scratch were analyzed with transition electron microscopy. It was found that the grain of recording layer, which is perpendicular orientated for PMR disk, was tilted under the scratch. The analyses revealed that the scratch resistance which includes tilting resistance is closely related to perpendicular orientated grain of recording layer. A dense and not-easy titled grain structure at recording layer is a must for a reliable hard disk drive.

View full abstract

A slider with an air-bearing surface that has a small spherical pad around the read/write elements on the trailing center pad was developed to reduce the meniscus and friction forces and slider clearance loss. Flying height modulation and slider instability are suppressed by the reduction of the meniscus force to less than 10% of the air-bearing lift force and the use of a spherical pad with a radius of less than 10 mm. Evaluation using an air-bearing surface model with a spherical pad showed that slider clearance was increased by 1 nm at a 5-nm nominal flying height. Evaluation using touchdown-takeoff testing of a spherical pad slider fabricated by depositing carbon on the center pad air-bearing surface by means of the lift-off resist technique showed that the spherical pad slider had a very small friction force and acoustic emission output up to a 5-nm interference height. It thus provides instability-free sliding in the near-contact regime.

View full abstract

This paper describes the dynamics of contact sliders with nano textures fabricated by femto second laser processing. First of all, the femto second laser processing method was developed in order to fabricate the texture on the DLC thin film pad. The contact slider experiments were carried out by using the slider with nano-textures, and the influences of nano-textures on the friction and slider dynamic characteristics were investigated in DTK disk as well as in Flat disk. As a result, the friction and vibration characteristics have been remarkably improved by the texture in both disks. And it was suggested that the optimum values of the height and area ratio of the texture were existed.

View full abstract

Recently, Head-Disk-Interface(HDI) spacing in Hard Disk Drives(HDD) has been decreased to as low as 10 nm in order to achieve an ultra-high magnetic recording density. With the increase in magnetic recording density, the HDI spacing of the head has been reduced to such an extent that the effect of the ultra-thin liquid lubricant films on slider dynamics has become more evident. The goal of this research is to clarify the effects of environment on slider hysteresis behavior. In this study, the slider hysteresis behavior was monitored by varying the lubricant film materials of the disk and environmental conditions, by using pump down pressure test. As a result, it was found that the effect of temperature on slider hysteresis behavior depends on the lubricant film materials. In addition, it was suggested that the variation in the hysteresis is caused by a variation in the friction forces between the slider and disk surface.

View full abstract

Recently, it is important to clarify the interactive forces between slider and disk surfaces in nanometer head-disk interface region in HDD, in order to achieve ultra-high magnetic recording density. This paper describes the interactions between atomic force microscope (AFM) probes covered by conductive diamond thin films and ultra-thin liquid lubricant films. In this study, AFM was set in the environmentally controlled chamber. We investigated the difference in a response of the force curve by varying the lubricant materials (Zdol2000, Ztetraol2000), relative humidity and lubricant film thickness. From the experimental results, it was found that meniscus bridge is easy to be extended at high relative humidity. Touch-down distance gradually increased with an increase in the relative humidity and was greater as the lubricant film thickness increased. On the other hand, adhesive force decreased with an increase in the lubricant thickness.

View full abstract

To decrease magnetic spacing on head/disk interface of hard disk drive (HDD), magnetic spacing variations due to manufacturing tolerances and environmental variations should be reduced. To solve this problem, thermal flying height control (TFC) technology, which carries micro actuator near magnetic element, is applied. TFC technology can control the magnetic spacing during HDD operation by applying power. It is known that reduction of flying height is compensated by increasing in air bearing force due to TFC protrusion. This effect obstructs efficient flying height control. Larger TFC power is required to decrease magnetic spacing further. To ensure the reliability of magnetic element and reduce consumption power of HDD, TFC efficiency should be improved. In this report, we have investigated theoretically and experimentally how to improve the TFC efficiency for air bearing surface (ABS) design. We developed prototype slider of improved TFC efficiency design and investigated TFC related characteristics. As a result, the new design shows higher TFC efficiency than that of conventional design.

View full abstract

To achieve ultra-low flying height, magnetic spacing variations due to manufacturing tolerances and temperature-induced thermal protrusion need to be reduced. We have developed a thermal flying-height control (TFC) slider that carries a micro-thermal actuator. Previous TFCs were mainly statically controlled by a constant power supply. Our purpose is to demonstrate dynamic control of a TFC slider to compensate for high-speed magnetic signal modulation using feed-forward control methods, hi this report, to dynamically compensate for magnetic signal modulation using TFC, two methods were examined. Method 1 adjusted TFC power using only time domain information. Method 2 adjusted TFC power using frequency domain information in addition to time domain information. Method 2 showed better compensation for magnetic signal modulation due to better compensation at higher frequencies. These results showed that a dynamically controlled TFC is feasible in compensating for kHz order modulation.

View full abstract

This report describes the development of a new soldering iron device with electric tweezers for small parts. It is a tool for a manual rework process to small surface mount devices and mainly composed of a gripping mechanism and a heating mechanism of gripper. We use tweezers using buckling phenomenon as a gripping mechanism because of its excellent performance in gripping millimeter or sub-millimeter size workpieces. And for the heating mechanism of gripper. we use simple heat conduction. We made two prototypes and evaluated their heating and gripping mechanism. Additionally, we made their analysis models of heating mechanism.

View full abstract

Basic research has been conducted on the three-dimensional formation and manipulation of magnetic gel-beads in the magnetic field for the formation of cell tissues such as blood vessels. Magnetic gel-beads were doped with magnetic nano-particles in alginate capsules. We formed chain-like clusters of gel-beads in the magnetic field and demonstrated that cylindrical three-dimensional patterns about 500 μm in diameter was formed by accumulating gel-bead chains on a two-dimensional magnetic circular pattern of magnetic seed particles. A micro manipulator was also developed to manipulate individual gel-bead.

View full abstract

Sound table tennis (STT) is the table tennis for visually handicapped person. There is a foul called the holding in STT. We tried to develop the judgment technique for holding in STT using batted ball sound Firstly, frequency characteristics of impact sounds of a racket, a ball and a table were measured, and then natural frequencies of them were determined. We proposed judgment technique of a batted ball sound based on the characteristic of the natural frequency. Finally, the effectiveness of the proposed method has been demonstrated.

View full abstract

A crutch is usually used for rehabilitation after getting injured by an accident. There are some who use crutches in a not good position of the body; it is very dangerous. That is why, the authors develop a system which can advise inexperienced users of crutches and warns them for their inadequate walking styles. As a gyro sensor and a pressure sensor are provided with the crutch, the motion of the crutch can be measured. In addition, the threshold values of angle and angular velocity are defined. So, if the walking condition with a crutch is over them, the walker can notice the inadequateness of the walking style.

View full abstract

This report focuses on a development of a 3-dimensional drag sensor. Three strain gauges and a nonmetal cylinder material constitute the sensor. The strain gauges are put on the side of the cylindrical material at intervals of 2π/3 radians. The strain gauges detect the deformation of the cylindrical material. In this report, we discuss the difference of the results caused by the difference of the position of the strain gauges put on the cylinder material. Moreover, the effectiveness of the sensor is examined through some experiments using the soft materials as the contact objects.

View full abstract

The small intestine is a component of the gastrointestinal tract; its approximate length is 3 m, and it is divided into the duodenum, jejunum, and ileum. Since the small intestine is fixed to the posterior abdominal wall only via the mesentery, the jejunum and ileum have high mobility; therefore, it was difficult to observe them by conventional endoscope. In recent years, the development of the double balloon endoscope and the capsule endoscope has enabled the inspection of all areas inside the small intestine. However, both these devices are inapplicable for the investigation of ileus patients. Therefore, we developed a new small intestine endoscope with an optimal fiber scope of 1 mm outer diameter and an ileus tube; this endoscope can be applied to investigate ileus patients. By this technique, in case the ileus tube is drawn outside the body, the all inspection inside a small intestine is due to be conducted. However, when the ileus tube has reached the small intestine end part, it is in the state where an intestinal tract is drawn in. Therefore, if the amount of water poured into the balloon is reduced rapidly, the part of the small intestine would be released, and the previously unobservable portion would be visible. In this paper, we developed a system to control the pressure within the balloon of the ileus tube and verified its performance.

View full abstract

In this research, we developed an MRI compatible 2DOFs manipulator for needle/device guidance controlled by intra-operative fluoro MR images. This system consists of a customized 0.2T open-type MRI, 3D position measurement system, PC for control and the 2DOF manipulator. This system operates as follows: 1) The target position is chosen from preoperative MRI. 2) The surgeon set-up the manipulator close to the entry position on the patient. 3) The position and orientation of the manipulator is calculated by using the 3D position measurement system. 4) The manipulator's arm is moved automatically towards needle insertion point based on the calculation result. 5) The surgeon inserts the needle/device through the manipulator's arm. 6) Navigation system will correct the needle insertion angle by intraoperative fluoro MRI (images are obtained 0.5Hz). The phantom experiments are conducted to evaluate the needle insertion accuracy, and the accuracy of 0.8 mm±0.29 mm was obtained. As conclusion, our system is sufficiently accurate and therefore feasible for performing the device guidance inside MRI environment.

View full abstract

In this paper we propose an EMG-Based control of a three degree of freedom (3-DOF) exoskeleton robot for the forearm pronation/supination motion, wrist flexion/extension motion and ulnar radial deviation. The skin surface electromyographic (EMG) signals of muscles in forearm of the exoskeleton's user and the hand force/forearm torque are used as input information for the proposed controller. By applying the skin surface EMG signals as main input signals to the controller, automatic control of the robot can be realized without manipulating any other equipment. Fuzzy control method has been applied to realize the natural and flexible motion assist. An experiment has been performed to evaluate the proposed exoskeleton robot.

View full abstract

This paper is a study on the development of active haptic sensor system for monitoring human hair under dry and wet conditions. The polyvinydene fluoride (PVDF) film, which is a kind of piezoelectric materials, is used as the sensory receptor. The sensor consist of a silicone rubber, a PVDF film, and a projection for the contact to objects. The sensor output is obtained by contacting and scanning of the sensor on the object. Evaluation using human hairs has problems due to randomicity, and difficulty of putting them uniformly without overlapping. Therefore, in this research panels imitating the physical and chemical properties of human hair are fabricated and used as measuring objects. By comparison between the sensor output and human sensory evaluation of the panels, it is confirmed that this sensor system is available for monitoring hair by both dry and wet condition.

View full abstract

Human skin, which mainly consists of epidermis, dermis and hypodermis, is the largest organ of a human body. It has a lot of roles, for example, protection function , moisture maintenance function and sensory function. Moreover, it becomes a parameter that shows the health condition and beauty, because the skin is the outermost layer of a human body. Therefore, the development of the sensor that can measure the skin conditions in various parts of the body is demanded. However, sensors that had been developed before can measure limited parts of body or can measure only in limited condition. In this paper, the sensor that can measure various parts of human body in various conditions is developed and evaluated by measurement of the artifical skins that have various roughness.

View full abstract

The purpose of this paper is to develop a remote control of "VTOL plane" with an embedded Linux board. It realizes simplification and miniaturization of a control unit, promotion of efficiency of programming and remote control by Internet.

View full abstract

This paper describes a telescopic-arm type, climbing robot support robot. Although there are various kinds of wall climbing robots, there is a possibility that they fall down due to the concavity and convexity of the wall or insufficient absorption power. To solve the problem, we aim at developing the wall climbing support robot with a telescopic arm. By utilizing the proposed robot, the wall climbing robot can climb the wall more reliably and safely. The experimental results show that the proposed robot can support the climbing robot efficiently.

View full abstract

This paper describes a control technique that can prevent the robot from losing balance due to a immediate acceleration by controlling only the acceleration and the posture of the upper-body of the robot. As the proposed technique controls the balance by measuring the upper-body's angle and angular velocity, it can be implemented independently from the main control system of the robot to be applied for various types of robots. To confirm the effectiveness of the proposed technique, we ran experiments via simulation, and on an actual robot.

View full abstract

For the future cohabitation of humans and robots, we are making research on home use robots, where human motion and environment must be precisely recognized. We used omnidirectional mobile robot with laser range sensor for this purpose, and made experiments on map building and human following. First, we adopted scan matching algorithm for the localization of mobile robot in the stable environment, and confirmed the map building capability by experiments. Next, we applied this algorithm to the mixed environment of human and robot, and succeeded to extract human motion and robot motion along with the map building at the same time. We confirmed the adaptability of scan matching algorithm to the human motion recognition which is the key to the human following by robots.

View full abstract

There are many persons who lost their sight and want to get more flexibility for their activities. But there are very small chances to get new guide dog by about 10%. So we started to serve a guide-dog robot for sight-handicap persons. In the first paper, algorithm of obstacle detection with image processing is proposed. We classified obstacles into three main categories "Pole", "Bar" and "Step" shape, and propose new parallactical difference method included stereo camera on moving vehicle, which detects pole and bar shape obstacles under in-house condition successfully.

View full abstract

We are developing a quasi-passive dynamic walking robot with swinging torso. Our experimental approach over several years to the real walking is really successful so far, and the robot walks not only on the horizontal plane but also on the gentle slope, yet the theoretical analysis of motion of this robot has been left unsolved. This time, we modeled the robot as underactuated mechanical links and formalized motion equations from the viewpoint of sagittal and lateral plane. We made discussions on the several assumptions in the modeling for the simulation experiments of the robot.

View full abstract

Based on the past experiments of the leg orthosis with powered knee joint for the spinal cord injured, we realized the necessity of stiffness/compliance design, smooth control of the mechanism, and energy saving concept. We are designing several types of quasi-passive walking machine from this viewpoint, and made many experiments so far. This time we designed ankle driven type of quasi-passive walking machine assuming to be applicable to the leg orthosis in the future. We described the design considerations of the driving mechanism and kinematic structure, and showed the basic experiments to evaluate the validity of machine design.

View full abstract

We are making research on a kicking mechanism that can kick a ball like a professional soccer player. We measured the human kicking motion for the purpose of searching optimal control algorithm of the kicking mechanism that is designed in parallel with this measurement. We analyzed several human kicks with/without approach steps of the free kick using a high speed camera, goniometers, and electro myoelectric signals (EMG). We confirmed from the experiments that the legs motion is like a whip in order to use kinetic energy effectively as literature says. The result of the analysis is feedbacked to the control of the current version of the kicking mechanism as well as the mechanical design of the next version.

View full abstract

We have proposed a system that supports the proficient operation of an electric wheelchair with acoustic information. The audio system provides the electric wheelchair user with acoustic information with the aim of conferring an intuitive feeling of how the wheelchair is operated. We made a straight-line-course with step to measure the force acting on a joystick and motion behavior of an electric wheelchair. We repeated a running test of the electric wheelchair for the same test subjects until they improve operation skill. We thereby demonstrated that there is a relationship between the force acting on a joystick and vibration dose value (VDV). And we made sounds based on operation of skillful subject to investigate whether or not to listening these sounds promote efficient operation of the wheelchair.

View full abstract

This paper is a study on the development of a sensor for measuring tactile sensation. An active sensing system using the piezoelectric effect of a PVDF (Polyvinylidene Fluoride) film is assembled. The sensor is attached on the tip of a robot finger driven by a piezoelectric bimorph strip and the root of the finger is mounted on a linear slider. An active sensing, slide, is introduced to collect the information on tactile feelings. 7 kinds of sensor surface are prepared and the output is investigated in order to improve the sensor. Next, haptic actions on fabrics by experts and subjects in general are examined. Finally, the relation between sensor performance and the variation of contact force is investigated. It is confirmed that there is the optimum contact force for the measurement, and by using the optimum contact force the sensor output have very clear correlation with human touch feelings. The obtained results showed that this sensor system is available for measuring tactile sensation.

View full abstract

In this paper, we propose a method that actively indicates a figure, based on haptic illusion. It aims to improve the accuracy of and the speed of the recognition by indicating not an actual figure but an illusion figure different from actual. The experimental result shows the possibility to improve figure recognition by using haptic illusion.

View full abstract

Laser-assisted magnetic recording is one of the novel technology for achieving a magnetic recording density of more than 1 Tb/in^2. In this technology, it is suggested that there is serious issues for the ultra-thin liquid lubricant films on the disk surfaces. This is because these films are heated to high temperature using laser beams. In this study, we focused on the thermal stability of the ultra-thin lubricant film in laser-assisted magnetic recording. In other words, the behavior of lubricant film due the laser beam with the parameter of Lubricant thickness and Bonded Ratio was investigated and discussed experimentally. As a result, it was found that the lubricant depletion was induced by both evaporation and thermocapillary stress. In addition, the depletion phenomenon was greatly affected by the lubricant thickness.

View full abstract

To further increase recording density of disk storage drives, laser-assisted magnetic recording can solve the fundamental programs of thermal fluctuation and is regarded as the keytechnology for achieving recording density of more than 1 Tb/in^2. In this technology, it is suggested that there is serious issues for the ultra-thin liquid lubricant films on the disk surfaces. Because they are heated to high temperature with laser beams. In this study, we focused on the thermal stability of the four lubricant film materials in laser-assisted magnetic recording. In other words, the behavior of lubricant film under the laser heating was investigated and discussed experimentally. As a result, it was found that the effects of lubricant materials on the lubricant film depletion were clarified. In addition, it was also found that the features of ultra-thin liquid lubricant film depletion characteristics can be explained qualitatively using the TGA result of each bulk lubricant material.

View full abstract

In the head-disk interface (HDI) of a hard disk drive (HDD), lubricant deformation may affect flying characteristics of the head slider, as the flying height decreases. The long wave equation was employed to examine deformation of ultra-thin but continuum liquid films. The steady state of lubricant deformation is analyzed using the linearized long wave equation with finite width. In this paper we analyzed i) lubricant deformation caused by applying a concentrated pressure and shear stress, ii) influence of disjoining pressure on liquid deformation and iii) lubricant deformation under the inclined plane slider.

View full abstract

To evaluate the coverage of thin lubricant films on magnetic recording media, a new method using CAICISS (Coaxial Impact Collision Ion Scattering Spectroscopy) was proposed. In this study, we reproduced the molecularly thin lubricant films on the carbon overcoat by molecular dynamics simulation, and calculated the coverage and fluorine-to-carbon atomic ratio (F/C ratio) assuming the CAICISS measurements. From the simulation results, we confirmed that the coverage measurement method using CAICISS can evaluate the accurate coverage of molecularly thin lubricant films.

View full abstract

To investigate the effect of UV irradiation on depletion and replenishment of molecularly thin liquid lubricant films coated over magnetic disk surfaces, we performed pin-on-disk sliding test using non-UV-irradiated, UV-irradiated, and partially UV-irradiated 2-nm-thick AM3001 films, respectively. With UV irradiation, the depletion area decreased by 39% whereas the time constant for replenishment increased by 18%, indicating that UV irradiation drastically enhances the antiwear performance of the lubricant films accompanying with slight decline in the replenishment performance. For the lubricant films patterned by partial UV irradiation, the antiwear performance was further slightly improved as compared with the UV-irradiated films, and the replenishment performance was found to be dependent on the pattern shapes.

View full abstract

To tailor the tribological performance of molecularly thin liquid lubricant films coated on magnetic disk surfaces, we have developed a method in which magnetic disks are first irradiated with UV rays through a mask and then lubricant films are applied to the disk surfaces. We confirmed that a concave-convex film structure with 0.37 nm thicker lubricant in the irradiated region was developed. The surface energy in the convex region was higher as compared with the concave region; however, the disjoining pressures in the convex and concave regions were well-balanced. We thus quantitatively demonstrated that the concave-convex film structure was induced by the disjoining pressure gradient between the irradiated and non-irradiated regions.

View full abstract

The flying height of the slider in HDD decreases recently, and the chance that the slider contacts with lubricant has increased. It is very important in low flying height to analyze the contact behavior of the head and the lubricant. In this paper, we report about slider behavior in contact with various lubricants. As a result, we found that magnitude of head vibration depends on lubricant. The relationship of vibration magnitude due to lubricant difference is to be contrary by if the observed vibration direction is in vertical or in in-plane to the disk. Furthermore, we showed the correlation between viscosity of lubricant and vertical head vibration.

View full abstract

Lubricant is applied on the hard disk for both the further reduction of flying height to achieve higher recording densities and maintenance of the reliability of the Hard disk drives. However, the lubricant pick-up phenomena, which is lubricant applied on the disk adsorb on the head by the relative motion between head and disk at ultra-low flying height, causes the flying stability to deteriorate. In this paper, we measured the film thickness of lubricant adsorbed on the slider surface under the condition simulating actual hard disk drive for various flying time and flying height. As a result, we observed that the lubricant film thickness becomes thicker with increasing flying time and reducing flying height.

View full abstract

In the head disk interface (HDI) of a hard disk drive (HDD), flying characteristics of the head slider is influenced by the intermolecular force, the instability of lubricant and the solid contact, as the flying height decreases. Therefore, the interface model considering these effect is important. In the present study, force curve, which is generally used for measuring the surface interaction forces in atomic force microscope (AFM), was analyzed theoretically by applying the interface model to the mechanical model of AFM measurement. In this analysis method, effects of parameters on force curve were investigated. Furthermore, it was found that the theoretical values agree well with experimental values.

View full abstract

Established ellipsometric microscopes have low resolution because diagonal observation set a limit to focused area due to focal depth of objective lens. In this paper, we represent a new illumination method. We arrange an objective lens pointing vertically downward to sample, and condense illumination light into back focal plane with shifted light from lens axis to peripheral spot. Therefore, we give off diagonal light from objective lens. Adopting this method, we can observe reflected light from sample in the same way of usual optical microscope. As a result, we can visualize fluid dynamics of nano-thick films with a high-resolution.

View full abstract

This paper is a study on the development of active haptic sensor systems for medicalwelfare. The operational performances of two sensor systems are investigated. The polyvinydene fluoride (PVDF) film, which is a kind of piezoelectric materials, is used as the sensory receptor. One is the palpation sensor for discrimination of prostatic cancer and hypertrophy. The sensor is effective to measure the softness of the object. The problems of the operational performance are clarified through a clinical test. The other is a tactile sensor for reading Braille. The operational performance tests were carried out by normal healthy and visually handicapped subjects. The problems of the sensor's properties are clarified. The sensors will be improved based on the finding for practical applications.

View full abstract

The objective of this paper was to present a method of measuring and identifying dynamics of the patellar tendon reflex. We designed an experimental method to measure reflex dynamics utilizing a body mounted motion measurement sensor and a hand-held instrumented hammer. A simple pendulum model was introduced to estimate the physical parameters including viscoelastic properties of the lower extremities, and to predict the response of knee joint torque on a sagittal plane. System identification was applied assuming a linear continuous time-process model to describe the system input-output relationship. A healthy adult male subject participated in our experiment. The method reliably characterized stretch reflex dynamics with a few simple system parameters of transfer function. It was supposed that the method was simple and feasible to help quantifying clinical manipulations and neuromuscular diagnosis in practical use.

View full abstract

This paper presents a local active tactile sensor with fluid for measuring hardness and surface conditions such as slimy, smooth, and others. This sensor is made of a silicone balloon catheter. The balloon is contacted with a soft object and expanded by using liquid. In the process of the expansion, the balloon pushes the object and the contact surface slips or fixes. This phenomenon depends on hardness and surface conditions of the object. The expansion can be evaluated by measuring the flow of the liquid. Experiments using the sensor are carried out on soft samples with various hardness and surface conditions. Results show that the sensor has a potential to measure these tactile information. Furthermore, the balloon that is the sensing element is very soft and flexible and does not need electricity. This sensor is available as a medical sensor since it provides safety for tissues.

View full abstract

[in Japanese]

View full abstract

This paper reports on a micro planar coil as a receiver for a high resolution MRI (Magnetic Resonance Imaging). In this study, a micro planar coil of 10 mm in diameter was fabricated. The MRI signal receiving device was made by attaching the micro coils to the tip of acrylic pipes. The signal to noise ratio of MR image taken by the micro planar coil was 8 times as high as MR image taken by medical MRI coil. MR images of okra (Abelmoschus esculentus) were acquired with 2.0×2.0×2.0 mm^3 and 0.5×0.5×1.0 mm^3 resolutions.

View full abstract