In recently developed magnetic storage systems, the spacing between the flying head and the disk has been drastically reduced to less than a few nm to facilitate ultra-high density recording. Furthermore, magnetic interference between adjacent data tracks is becoming significant by reducing the spacing between the flying head and the disk. For that reason 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 ultra-high densities. The interaction stresses and forces are changed due to the distribution of materials on the disk surface. In this paper, we established an analysis method of interaction stresses acting between solid surfaces considering two-dimensional periodic material distribution based on Lennard-Jones potential by using Fourier series expansion.

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Vibration characteristics of a head slider in hard disk drives in proximity and contact regimes attracts strong interest because head-disk spacing must be decreased to less than 1 nm in order to increase recording density. This study first e valuates head-disk interfacial force based on rough surface adhesion contact models and air-bearing force model. Then, microwaviness (MW)-excited vibration of single-degree-of-freedom slider model at touchdown was simulated by Runge-Kutta method. It was found that the slider exhibits a large spacing variation having low frequency components of less than 100 kHz near the boundary of with or without static unstable region. When a small static unstable region appears, occurrence of low frequency spacing variation is interrupted by temporal flying state (loss of contact). When the static unstable region further increases, low frequency spacing variation can appear only at the beginning of contact and contact vibration with a normal resonance peak appears in two spacing ranges separated by perfect flying (loss of contact) state. These calculated results are consistent with actual slider vibrations at touchdown process.

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The slider/disk spacing of magnetic disk drives has been reduced to less than 2nm by using the thermal flying height control system in order to increase the recording density. In narrower slider/disk spacing, the effect of surface roughness on the flow characteristics is not negligible and it may affect the flying performance of slider air bearing. We introduced Direct Simulation Monte Carlo method (DSMC), and the flow characteristics against narrow spacing with surface roughness was analyzed. The effect of surface roughness on the flow characteristics was also estimated by using molecular gas-film lubrication (MGL) equation, as well. The both results were compared and the characteristics of surface roughness effect ware examined.

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We have proposed a method to solve a differential equation using the spreadsheet function of Microsoft Excel. An advantage of this method is simplicity because the same procedure can be followed to solve an ordinary differential equation or partial differential equation. Using this method, second order ordinary differential equation with boundary conditions and time dependent Reynolds equation for gas lubrication problem was solved numerically. The results obtained by the method are in good agreement with exact solution.

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A high-performance interference microscope was integrated with a previously developed pin-on-disk type friction tester. This allows us to in situ observe the contact region between the pin and disk mediated with nanometer-thick liquid lubricant films, and to measure the sliding-induced vertical displacement of the pin with subnanometer resolution. Our experimental results showed that the vertical displacement of the sliding pin rapidly increased with respect to the sliding speed and then saturated. The saturation value increased with increasing thickness and viscosity of the liquid lubricant films. We also observed changes in the flow behavior of the lubricant films depending on the sliding speed. From these results, we infer that nanometer-thick liquid lubricant films can generate upward hydrodynamic pressure and exhibit behavior like fluid lubrication.

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Surface texturing is attracting much attention especially in the tribology field because for the effect improving the lubrication properties. However, most of studies on surface texturing conduced in the past focused the lubrication properties under a static load, and there are almost no papers on the dynamic characteristics of textured surfaces under a squeezing condition. From these backgrounds, the purpose of this research is to grasp the oil film behaviour on the textured surface under vertical vibration that simulates repeating squeeze motion. The oil film behavior under squeezing motion was observed by means of optical interferometry with two-color light. The experiment showed that the oil film shape in the contact circle under squeezing motion changed due to the existence of microdimples. Particularly, when the glass surface with 500 nm-depth microdimples was used, the oil film became thicker and the contact area became smaller than that when the non-textured surface was used.

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Measurements of surface forces are very important for surface science and engineering, and therefore have been studied by many researchers. Though the effects of surface roughness on reduction of adhesion forces have been discussed statistically by Greenwood, Persson et al., few deterministic researches can be found. In this study, we developed an experimental system that can measure the surface force and the surface roughness at the same position. The effects of the surface roughness on the reduction of the adhesion forces were clarified deterministically using the newly developed system.

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PFPE/DLC hybrid overcoat was deposited by the photoelectron assisted CVD (PACVD) with RF pulse bias voltage. The properties of PFPE film on DLC surface deposited by PACVD was compared with those by the CVD with the glow discharge plasma. The deposition rate of PACVD was much lower than that of the glow discharge plasma. The surface energy of PFPE films by PACVD was approximately 15 mJ/m² and that by the glow discharge plasma was 50 mJ/m², and the estimated monolayer thickness of PFPE film deposited by PACVD was 7−8 Å. The PFPE film deposited by PACVD had much CF₂ structure at the surface, however, that deposited by the glow discharge plasma had much COO and CF structures. From these results, we estimated that the glow discharge plasma much dissociated the chemical structure of monomer PFPE gas molecules as precursor and the deposited film could not show low surface energy.

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To increase HDD capacity, the thickness of lubricant film on the magnetic disks need to be reduced. The lubricant film deposited by using the photoelectron assisted chemical vapor deposition (PACVD) with low molecular weight perfluoropolyether (PFPE) lubricant showed high bond ratio, low surface energy and high coverage. In this study, we compared the tribological performances on head-disk interface of PFPE lubricant films deposited by PACVD with DC bias voltage and RF pulse bias voltage. As the result, the lubricant film deposited by DC and RF pulse voltage showed very high touch down power (TDP). In addition, the lubricant film deposited by RF pulse voltage showed low slider wear.

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Among many organic vapor contaminants released from structural components of hard disk drives, organic siloxanes are particularly ominous, as they can be released in a relatively large quantity. Adherence of organic pollutants to the disk surface is a factor that hinders the normal operation of the head and the disk surface. It is known that volatile siloxane oligomers such as D4 (octamethyl cyclotetrasiloxane) often form cyclic polydimethylsiloxane polymers in the presence of acidic catalysts. We investigated the reaction between D4 and some carbon materials such as diamond-like carbon in hard disk and graphite. The effect of the protection of carbon materials by Perfluoropolyether (PFPE) lubricants was observed.

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Siloxane outgas is well known to cause the smear on magnetic head sliders. Siloxane outgas is vaporized from a part in hard disk drives (HDDs), that adsorbs on the magnetic disk surfaces, and SiO2 denatured from siloxane by the flash temperature at a slider and disk contact is accumulated on the slider surface. On the other hand, the heat assisted magnetic recording (HAMR) is being developed to improve the areal density. In HAMR, a laser light heats the magnetic disk surface by 400 − 500 K. If siloxane is adsorbing on disk surface, that easily desorbs from disk surface and that may thermally dissociates by laser heating. In this study, we studied the smear growth from siloxane outgas at laser heating. As the results, we confirmed that the siloxane adsorbed on disk surface grew on the glass surface opposed to disk surface at the laser heating spot.

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To further increase recording density of disk storage drives, the heat assisted magnetic recording (HAMR) can solve the coercive force problem of thermal fluctuation and is regarded as the key technology for achieving recording density of more than 1Tb/in^{2 (1)(2)}. In this technology, it is suggested that there are serious issues for the diamond like carbon (DLC) overcoat on the disk surface. Because that is heated to high temperature with laser beams⁽²⁾. In this study, first, we measured temperature dependence of friction properties of non-lubricated DLC surface on magnetic disks. Second, we considered the influence of the accumulated smear on test pin surface during the friction test. As a result, it was estimated that the smear on pin surface accumulated by the laser irradiation was originated from the hydrocarbon contamination adsorbed on DLC surface.

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To design head disk interface of hard disk drives (HDDs) using heat assisted magnetic recording, it is important to reveal temperature effects on shear properties of nanometer-thick liquid lubricant films. For this purpose, we conducted molecular dynamics simulations of a liquid film of perfluoropolyether which is subjected to confined shear between two carbon plates under conditions of different temperatures and shear speeds. The results of the simulations indicate that the rate of change of shear viscosity with temperature becomes smaller with increasing shear rate and the temperature dependence of shear viscosity is almost negligible under the condition of high shear rates which are typical for HDDs.

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Sufides as MoS₂ are known as solid lubricants. These materials are also known as thermoelectric materials. However, there is no materials satisfied both functions at the same time. In this study, sulfides powders such Cu₂S (chalcocite), SnS, Cu₅FeS₄ (bornite) were synthesized under vacuum condition. Some specimens were evaluated by friction tester and their lubricity, not only sintered sulfied but also blended and sintered sulfides with bronze powders were compared. Other specimens were evaluated their seebeck coefficients, that is one of the thermoelectric properties. Experiments results of the seebeck coefficients were compared with simulation results. As a result, it was found that SnS and blended SnS with bronze had indicated better friction properties. For thermoelectric properties, seebeck coefficient of Cu₂S had matched with experiments and simulation. Totally, Cu₂S (chalcocite) has superior properties as both solid lubricant and thermoelectric material.

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Electro-conjugate fluid (ECF : Electro-conjugate Fluid) is one of the functional fluids. ECF has a remarkable property that a strong jet flow is generated between the electrodes when a high voltage is applied to ECF through a pair of electrodes. The authors had developed an ECF-pump utilizing this strong jet flow with simple structure and no noise. Furthermore, by the use of the ECF-pump, a liquid cooling system by ECF had been fabricated. On the other hand, ECF is insulating liquid. By focusing on this point, it seems to be possible to develop an immersion cooling system which is used in supercomputers and a personal computer. In this study, an immersion cooling system by ECF is proposed and fabricated. Based on some experiments, the possibility of achievement of the system is made clear.

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Devices equipped with internally rotating elements are widely seen in industrial applications. In such devices, complex flow is driven by the rotating parts. Knowledge on such flow plays an important role in improving the reliability and performance of the devices. In present study, we focus on the flow driven by a pair of rotating disks within an enclosure, which models a hard disk drive (HDD). Three-dimentional structure of the unsteady fluid flow is investigated at three different planar angles of arms penetrating into the area of the rotating flow. We performed a series of numerical analysis based on Large Eddy Simulation (LES) with an open sourced platform of OpenFOAM®. The results of the numerical simulation are compared with those of experiments with particle image velocimetry (PIV). Complex features of three-dimentional flow are found in the velocities, pressure, vorticities and stream lines near the arm and shroud opening area.

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It was known that Helium would improve Head positioning accuracy of Hard Disk Drive (HDD) due to its smaller molecular size comparing with air. But Helium sealed HDD was not available for a long time due to technical difficulty of sealing design and process. We developed Helium sealing technology and HGST started to manufacture 1^st Helium sealed HDD in the world in 2013. Helium sealing technology enabled much larger capacity due to much higher mechanical packaging density using thinner arms/disks, lower power consumption, lower idle acoustic noise and longer MTBF (Mean Time Between Failures). Now more than 12 million Helium sealed HDDs were shipped. Helium sealed technology is the enabler for high capacity HDD and Helium sealed HDD became industry standard in Capacity Enterprise HDD market. This paper briefly covers the information of sealing technology, dynamics design and product.

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In this paper, characteristics of disk flutter (natural frequency of disk modes, modal damping ratios, and modal excitation caused by flow) were studied by using a HDD filled with air, helium, and their mixture gas. In our experiments, amplitude of disk flutter decreased as the fraction of helium in the mixture gas increased but was not simply proportional to the gas density. This contradicts the general understanding that the amplitude of disk flutter is proportional to density of fluid in a HDD. Analysis of modal parameters showed disk flutter excitation varied with respect to the helium-air mixture ratio in the same manner as the disk flutter amplitude. From the behavior of the excitation factor, we categorized three regions on the basis of the gas density ratio, i.e., the ratio of gas density to air density in 1 atm. at room temperature: the transitional region is helium-rich, the critical region is mid-way between the other regions and the turbulent flow region is air-rich.

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DSA suspension is used for an accurate Head positioning in HDD. Co-located DSA suspension achieves higher accuracy than milli DSA suspension because co-located DSA suspension doesn’t excite the arm mode if the design is optimized. It is important that the slider rotation mass is balanced about the rotation center. This paper reports one of the methods of optimization of co-located DSA suspension.

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In a magnetic-head-positioning system of hard disk drives (HDDs), it is hard to analyze an effect of mechanical resonances beyond the Nyquist frequency after the HDDs were assembled. However, unexpected variations of the mechanical resonances often happen in actual HDDs because HDDs are mass-produced products. To solve such a problem, this paper introduces an analysis method of open-loop characteristics beyond the Nyquist frequency for the magnetic-head-positioning system of HDDs. This method enables us to analyze characteristics of the magnetic-head-positioning-control system including intersampling oscillations by using measurable open-loop characteristics. To show a validity of the proposed method, this study demonstrated simulation analyses on the magnetic-headpositioning-control system of the HDD. Simulation results show that proposed open-loop characteristics are good approximated solutions.

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This paper introduces a data-based controller design method to compensate for external disturbances in head positioning systems of hard disk drives (HDDs). For increasing a data capacity of HDDs, head-positioning-control system must compensate for any disturbance which worsen positioning accuracy. It is an important design problem how to compensate for external disturbances in the head positioning system. The mathmatical of exteranal disturbances are difficult to identify, therefore, the ideal controller cannot be designed theoritically. In this study, we have proposed the databased controller design method to compensate for the external disturbances in the head positioning systems of HDDs. Experimental results shows the designed controller can compensate for the external disturbances in head positioning systems of HDDs.

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We have developed a user-friendly loop-shaping method employing the Robust Bode (RBode) plot for optimizing an H∞ controller in a magnetic-head-positioning system of a hard disk drive. The RBode plot represents the robust performance criterion as allowable and forbidden regions on the controller Bode plot. As a result, control engineers can easily optimize an existing H∞ controller so that the control system gets the better performance against perturbations of the controlled object. In the proposed method, there is no need to construct the transfer function models of the controlled object and of the disturbance. Simulation results for a track-following control in the hard disk drive show the utility of the proposed method.

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We have developed freestanding bio-friendly nanosheets with a thickness of less than 100 nm for biomedical applications. These nanosheets represent unique properties such as good adhesiveness, amazingly flexibility, and a high degree of transparency. In this lecture, we introduce a series of the bio-friendly nanosheets developing in our laboratory and their biomedical applications. As components of the nanosheets we focused on various bio-friendly polymers, e.g. typical biodegradable polymers such as poly(L-lactic acid) (PLLA). These nanosheets were fabricated by simple processes of spin-coating and a novel peeling technique from the substrate using a water-soluble sacrificial layer. The obtained nanosheets acted as innovative wound dressings for incised organs and burned skin. These nanobiomaterials therefore constitute a promising alternative to conventional therapies and coating/wrapping techniques in biomedical fields.

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We propose a new gripper based on the jamming of granular material. In manufacturing fields, the gripping and holding of a wide range of objects such as not only objects with complex geometries but also flat objects are key tasks. In order to grip the flat objects by the gripper, we developed vacuum function for the jamming gripper. The paper describes the mechanical design, and the gripping performance with the various objects and durability performance of the developed gripper.

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In this study, we examined the fabrication of polymer ultra-thin films(nanosheets) using a micro gravure printing method. Conveying speed of the plastic film substrate, the concentration of solution, rotating speed of the micro gravure roll ware investigated experimentally for effects on the film thickness of the nanosheets. And, we evaluated the Young's modulus of the nanosheets were fabricated, also investigated in detail the physical properties such as flexibility and surface roughness, futheremore, surface of the nanosheet was microfabricated by embossing. Thereafter, the surface was observed using a laser microscope. it was possible to obtain new knowledge about the creation process nanosheets using the micro gravure printing method and embossing.

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We developed equipment for direct measurement of viscoelastic characteristics in high-frequency range without applying the time temperature superposition principle. So we proposed the first resonance compensation method to know viscoelastic characteristics in the high-frequency range. Then we can know accurate viscoelastic characteristic in the natural frequency (about 7.5kHz). Consequently, the result confirmed that the directly measurement obtained using the proposed equipment and compensation method reflect accurate viscoelastic characteristics up to 7.5kHz with less than 10% error.

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In recent years, attention has been paid to a printed electronics technology for producing a lightweight and flexible flexible device by printing a conductive ink on a thin and flexible continuous medium web. We focused on thin film pressure sensors among flexible devices fabricated by printed electronics technology. Since it was found that ink was played on the substrate and each printing surface when the sensor was fabricated, in this study, the wettability of the substrate and each printing surface in the sensor manufacturing process was evaluated.

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Size separation of large DNA molecules (10 kbp – 1000 kbp) is one of the fundamental procedures for identifying bacterium’s genotypes, which should be fast for quick defection of infectious diseases. In our conventional study, we developed an electrophoresis microchip based on size exclusion chromatography. This separation has an advantage that it does not cause large deformation of DNA, which is important for separation of large DNAs because they can be easily fragmented. We achieved separation of large DNAs (48 kbp + 166 kbp) driven by a direct electric field as electrophoretic condition of DNA. However, it caused long separation time (3000 s) because DNAs migration was slow due to low applied voltage for the separation. In this study, we achieved faster separation of DNAs using a pulsed electric field under which applied voltage can be higher.

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Dragonfly wing is deformed in the tip side from the nodus, which is vein structure unique to dragonfly. Wing deformation is thought to correspond to feathering motion in flapping flight. However, dragonflies perform a feathering motion actively. In this study, the effect of the nodus structure of wings on flapping flight with feathering motion was investigated using fluid-structure interaction analysis. Moreover, artificial wings with nodus structure were fabricated, and the flight test of micro air vehicle with artificial wings that mimic nodus was carried out. As a result, when the feathering angle is 20 deg or less, the nodus wings reduce drag force by deformation of wings and rise the efficiency of lift. In the flight test, micro air vehicle with artificial win gs that mimic nodus is successful in the takeoff and forward flight. Therefore, the nodus structure of a wing is of benefit to the flapping flight.

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The dragonfly has high flight capability in spite of very small size. Therefore, the flight characteristic of dragonfly has been investigated by many researchers. On the wing of dragonfly, there are micro structures have excellent flying abilities . In this study focus on micro structure of wing surface and micro structure of leading edge. These two micro structures are artificially reproduced. The wing with different combination of two micro structures and the wing with no structure are reproduced as text wings. The air characteristic of these micro structures experimentally are verified with using test wings. Drag measurement results showed decrease of drag value in the test wing with microstructures.

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A closed tube sampling (CTS) is a sampling method in which the sharp tip of a nozzle goes through the rubber cap of a sample tube and aspirates a part of the liquid in the tube. The purpose of this study is to develop a nozzle that has high durability (requires low insertion load) and produces few rubber chips when inserted through the rubber cap. It was found that the parameter that influences the insertion load most is the angle of the taper. Rubber chip production could be avoided with the combination of an angle smaller than 28.5° at the nozzle chip for smooth insertion and an angle larger than 15.0° at the inside edge for preventing cutting rubber off. Finally, to validate the durability and effectiveness of this shape, the nozzle was subjected to a test in which it was inserted through a rubber plate 50,000 times. Results showed that there was almost no nozzle abrasion nor increase of insertion load.

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In this study, we have proposed and developed an in vitro embryo production device which allows three steps of sperm selection, fertilization and culture on a microdevice. To realize this concept, we integrated the sperm sorting function combining with swim-up and swim-down methods onto the device. To evaluate the device functions, sperm sorting experiment, embryo production experiment, embryo culture experiment and IVF experiment have been carried out. As results, we concluded that the device has ability to produce high quality embryos by integrating the sperm sorting function. This concept will open and enhance the management of an individual embryo for assisted reproductive technology, livestock breeding, and fundamental stage research by further development.

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In this study, we evaluated the suction forces in the directions vertical and parallel to the contact face focusing on the diameter of the single suction cup of micro suction cup array. The suction force was measured by varying the pressing force during the attaching process of the micro suction cup arrays to the object. Three types of the micro suction cup arrays were fabricated and evaluated. The diameters of the single suction cup of the arrays were 100,150,300 μm. We confirmed that the both directional suction forces of 100 and 150 μm suction cup arrays increased with the increase of the pressing force reaching constant values.

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A conventional power supply method using a drive line for a ventricular assist device causes infection diseases, which decreases patient’s quality of life and survival rate. A possible solution is to use a transcutaneous energy transmission system utilizing electromagnetic induction. However, it is necessary for the coil to be located on the body surface accurately because of short transmission distance. In order to avoid infection diseases as well as increase the transmission distance, we proposed the new system utilizing magnetic resonant coupling that embedded flexible coils into clothes to transfer energy. In this paper, we evaluated the influence of the electric characteristics of the human body on the transmission efficiency by using both phantom and pork. The measured transmission efficiency with a gap of 30 mm was 67 % in phantom and 70 % in pork while that in air was 80 %.

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This study was conducted to present a feasible method to assess gait characteristics using a body-mounted IMU applied to clinically validated six-minute walking test (6MWT) in a hospital. We quantified the improvement of walking performance objectively in the lumbar spinal stenosis (LSS) patients before and after surgery. Spatiotemporal gait factors were estimated from the measures of IMU, with algorithms of processing only steady walk periods from the over ground shuttle-walking trial. Subsequently, three-dimensional rotation angles of the upper body were calculated to evaluate regional amounts of postural sway during walking. Presumably, variations in gait factors or postural walk performance were characterized as an expression of improvements in comparison with LSS patients before and after surgery.

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We developed the measurement system of blood drawing motion using the artificial blood vessel phantom. When the expert person such as a nurse collects the blood samples, they check the position and depth of subject's blood vessel by their visual sensation and palpation. Then they prick the subject’s arm with the needle. During inserting the needle in vein, expert person sense the force from needle when the needle punctures the skin and the blood vessel. They use this information to set up the needle correct position adjusting the position and angle of the needle. In this study, we tried to evaluate the blood collecting motion using the artificial blood vessel phantom with three-dimensional motion analysis system and six-axis force/torque sensor. As the result of experiments, we can clarify the relationship between the needle positions from the skin surface and axial direction resistance force when the needle punctures the skin and the blood vessel.

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Human beings gain a lot of sense by using haptic perception. Especially, the sense of hardness is important for physician to palpate patients’ bodies. However, it is difficult to share the sense of hardness. Therefore haptic hardness sensor systems are demanded. For the development of the haptic sensor system, it is necessary to elucidate the mechanism of human perception about the sense of hardness. In previous studies, it has been clarified that not only physical property about objects such as young’s modulus but also contact state such as contact area affects the sense of hardness. Therefore, this study aims to measure contact state of finger-tip during evaluating hardness for flexible objects. For this purpose, measurement system using Optical Coherence Tomography was developed. And contact area and three-dimensional contact shape during evaluating hardness for flexible objects were measured.

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The accidental swallowing caused by decline of the ability to swallow due to aging is a severe problem for elder people. Therefore, effective methods of monitoring swallowing action and estimating swallowing function are required. In this paper, a piezoelectric film sensor is developed to estimate the swallowing function. To investigate the relationship between swallowing action and sensor output behavior, pharynx movement is measured by using the piezoelectric film sensor and three-dimensional motion analysis system. In experiments, we measured the swallowing action during repetitive saliva swallowing test that is a major screening test for dysphagia by using the developed sensor system. As a result, it is found that number of swallowing can be evaluated by using the standard deviation of the developed sensor output.

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Authors have proposed a simple tactile nail chip made of a quenched ribbon steel, which is a wearable device attached on the nail to bend the nail inside. Previously, we verified the effect of the simple tactile nail chip that changes the tactile sensitivity through psychophysical experiments. In this paper, we conduct a roughness evaluation experiment with several types of simple tactile nail chips with different curvature and width, which bend the nail with different intensities. Experimental results show the change of the tactile sensitivity is influenced by the intensity of the nail-bending and there are great individual differences in the sensitivity change.

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We are developing an automatic guided vehicle with a robot arm for automation of conveyance in manufacturing lines. It is required for the robot arm not only functionality but also safety, compactness, and low power consumption. We developed a robot arm with gravity compensating mechanism to cancel arm's own weight. By using this mechanism, it is possible to use low power motor and reduce power consumption. In this paper, we report the outline and feature of AGV with a robot arm.

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Studies on the underwater vehicle: UWV are classified into automatic control called AUV and wired control type: ROV. In recent researches, attention has been focused on The AUV. Most of AUV studies have been focused on attitude control systems. However, few researches attempted position control systems. Generally, coordinates of the AUV is obtained from the mounted sensors. An error is generated every time the coordinates obtained from the sensor move by external force. Therefore, an error occurs in the estimated position of the AUV. The purpose of our research is to propose position tracking control of AUV. This paper, a novel control system for the position control is proposed, and developed small size AUV . Finally, position control performance of developed AUV is experimented.

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Recently, the robots which work in a hospital and factory have developed. The robot is expected to omnidirectional motion to move in limited space. For Mecanum wheels to be used in the wheels of the omnidirectional mobile robot has a complex structure. It’s depends on the situation of the road surface. Also, the motion control on the assumption of slip control becomes to be difficult with slippery road surface. In this study, the development of the omni-directional mobile robot equipped with Mecanum wheels. And in order to improve the motion of the efficiency, it performs a slip correction and disturbance observer are proposed. Finally the running performance in the actual road surface is verifined.

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We present a cooperative formation control method for multiple mobile robots based on visual information. Each robot needs recognize other robots for cooperative tasks. In order to reduce false recognition of the robots, we propose the detection of the robots by fusing visual information. In this paper, each robot estimates the center of gravity of tracked robots from the image data captured by equipped camera based on a particle filter. Then, the robot determines the velocity command so as to track other robot using the image-based controller and the estimated image positions. Experimental results using real three robots demonstrate the effectiveness of the proposed method.

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It is important to consider the usability such as the comfortability or controllability in the case of automobile design. In this study, driver’s EEG signals during acceleration operation in a driving simulator have been analyzed to evaluate the comfortability of the driver. Natural and unnatural acceleration patterns were prepared for the experiment. The experimental results show that comfortable feeling and uncomfortable feeling of a driver might be distinguished by monitoring the variation of EEG signals of 18~23 or 38~43 Hz.

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The objective of this study is to develop a novel mouse device that can present slippages to users via their fingertip skin: the device is called an “active wheel mouse” in this paper, which is a mouse that embodies an active wheel being rotatable in any directions, with any speeds and with any duration times. Through the slippage stimuli, the interface can present line-segment directions and lengths to users. In this paper, line-drawings being connected with some line-segments were presented. Furthermore, two kinds of presentation methods: with/without positional feedback were prepared. By measuring length and direction of each of line-segments, a feasibility of the interface and the presentation methods were confirmed.

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In recent years, with the development of IoT technologies, biological information of users has been easily acquired and accumulated. It is required that user's cognitive or emotional state could be accurately identified from such biological information. Various researches have used machine learning or deep learning however, generalized methods to handle biological data have not been established. In this paper, we propose a more versatile method using convolution neural network of deep learning to extract features from individual biometric information which is multi-channels time-series data representing user’s cognitive. We demonstrate a new method of extraction and distinguishment of features from cerebral blood flow, skin temperature, respiration and skin conductance measured during specific task conditions in the stroop experiment.

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Processing for the visual stimulation is different in a central field of vision and in a peripheral vision. Therefore we make a device showing visual stimulation to the peripheral vision area as certain information. We have screen of angle of field right and left for each 70 degrees on lateral direction 6m lengthwise direction 1.5m. Computer graphics of the driving scenery is reflected to the screen. We measured the characteristic of the peripheral vision with this simulator.

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We studied the differences in performance between beginners and expert musicians by taking cello performance as the object of our research. We found the two differences both performance technique (bow motion) and playing sound between beginner and expert players. Improvement of bow motion by learning textbook on basic cello performance reduced the “husky sound” at the start of playing. Next, we created effective sound information based on the envelope of playing sound of expert players. We conducted experiments in which subjects used this acoustic information and were led to become more proficient on both envelope and frequency characteristics of playing sound.

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We have been proposing and developing acoustic systems to support improvement of machine operating skills. In this research, we conducted operation experiments for low-vibration using a self-constructed moving-pendulum. An operator is asked to listen to acoustic information and operate a joystick based on that information. For this experiment, we developed an acoustic information system for operating support using sound-pressure changing in white noise output from headphone. Experimental results show that this system was effective in assisting operators in operation experiments of moving-pendulum and low-vibration characteristics could be obtained.

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To assist not only motor function but also perception ability of elderly persons and/or handicapped persons, the power-assist robots which has perception-assist function have been studied. These robots can automatically modify the user’s motion when the robot detects inappropriate user’s motion or a possibility of accident such as collision between the user and obstacles. For motion modification in perception-assist, some actuators of power-assist robot are used. On the other hand, since some elderly persons, handicapped persons or some workers need not use power-assist but only perception-assist, another simple perception-assist method was investigated in our previous study. In this perception-assist method, only vibrators are used for generating motion change with kinesthetic illusion to assist perception-ability only. In this study, since the perception-assist is often used during tasks under loaded condition, the features of motion change under loaded condition are investigated.

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