We present two-dimensional micro-chip for electrically-induced bubble injection. The electrodes which are patterned and integrated in the limited space enable to eject multiple-high-speed mono-dispersed bubbles. For the present study, fundamental processing method to fabricated two-dimensional chip is presented. The novelty of injection mechanism, which is produced by the closed space at the tip of the electrode, is fabricated by original packaging techniques. Multiple injections of high-speed bubbles in microfluidic chip provide efficient high-density injection. This study has possibility to control the area and density of injection by two-dimensional or three-dimensional injection techniques in the limited space and which can contribute to a wide range of applications such as gene therapy and other biomedical treatment.

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Hopping robots attract attentions for social utilization of humanoid robots. Constant-height hopping based on energy was researched by some researchers. The conventional method dealt with energy as an implicit variables, and position, velocity, or force are the main control variables. On the other hand, the approach of this paper is controlling mechanical energy directly while position, velocity, and force are parameters. The proposed method does riot require solving partial differential equations compared to the conventional method. Control of mechanical energy is conducted by feedbacked P controller. The validity of the proposed method is confirmed by experiments in a vertical linear motor. The desired hopping height is realized from the first hop.

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Various robots to search in uneven ground have been developed. Carrying robots in uneven ground has a risk of injury to operators. If robots are able to throw in uneven ground, it is safe, easy and valid. To do this, it must be a durable robot. We have developed a quadruped robot with spherical shell what it is able to throw in uneven ground. Furthermore the successor can roll by infinity rotation of legs and a spherical shell. In this paper, the purpose of this study is to allow locomotion by changing disposition of leg without infinity rotation.

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In embryology, researchers mundanely identify specific protein on embryos using monoclonal antibodies, however the process of immunostaining is complex and takes long time by comparison with conventional methods. We have proposed a microfluidic device that can allow multi-embryos to expose to different reagents simultaneously. The device has 16 inlets and reaction chambers, and solutions are applied to them by use of a syringe pump. However, cost of using the syringe pump units and microfluidic device is expensive. The purpose of this study is to decrease running cost of the device for its commercialization. We tested usage of a low cost micro-ring pump and reuse of the device. As the result, we achieved to reduce more than 80% of the cost.

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It is important to monitoring the environment of each biological cell growth with a development of the bioengineering field. For the present study we propose a micro-scale magnetic tag to be injected to the biological cell to identify the individual information of each biological cell. Currently, several processes to fabricate micro-magnetic tags are proposed. The proposed tags express the information by magnetization of magnetic micro-tool and patterning them. The further study is undergoing to have high density information by arranging tags in the limited space and also the method to inject them in biological cells. This study can contribute to optimize growing environment of biological cells and materials.

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In this paper, we report the development of liquid concentration sensor using crystal oscillator circuit embedded in a robotic artificial skin. We optimized the shape of the sensing capacitor for sensing a small quantity of liquid locally. This sensor is composed of the sensing capacitor and quartz crystal resonator (QCR). The frequency of QCR changes by a liquid in contact with the artificial skin on the sensing capacitor. Because the frequency changes relate to the electrical characteristics (dielectric constant, conductivity) of the liquid, the sensor can measure the concentration of the liquid. This sensor is expected to be applied to a sensor embedded in the robotic artificial skin.

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In recent years, we developed the application using self-oscillating polymer gels. The self-oscillating polymer gels are realized by incorporating the Belousov-Zhabotinsky (BZ) reaction to stimuli-responsive polymer gels. Self-oscillating polymer gels perform peristalsis and pulsatile motion, generating waves periodically propagated in the gels. However, BZ reaction generates carbon dioxide. Generation of carbon dioxide is a problem for the application. Recently, the bubble free BZ reaction has been found. The bubble free BZ reaction is realized by using 1.4-Cyclohexanedione (CHD). However, the physical and chemical condition for the self-oscillating polymer gels is not revealed. In this study, we investigated the concentration of the solution and examined the conditions that can be observed displacement of the self-oscillating polymer gels.

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In recent years, polymer gels have been actively studied. Polymer gels are promising as functional materials, and cause a drastic volume change by external stimuli such as temperature, pH and electric field, etc. These smart gels have been applied to soft robots and micro pumps. Previously, we have studied the self-oscillating gel. Self-oscillating polymer gels generate the cyclic volume change. Self-oscillating motion of the gels is generated by the chemical energy of the Belouzov-Zhabotinsky (BZ) reaction. Normally, self-oscillating gel generate the local swelling waves. In this study, we found that the gel generated the local contraction wave under the stretched state.

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Soft materials have distinct function and their characteristics are different from those of metals. Until now, we have developed the active BZ gels. BZ gels can oscillate in volume using non-linear chemical reaction and be innovative materials for medical devices. In previous study, it was found that the BZ gels could generate the large deformation under external load. Herein, we analyzed the mechanical behavior of pre-stretched BZ gels. For this purpose, we developed new tensile system for gels. We measured tensile force of BZ gels in swelling state and shrinking state. We could observe stress oscillation of pre-stretched BZ gel.

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In this study, we have proposed a microfluidic platform which generates an oxygen concentration gradient in a micro environment for reproducing the hepatic lobule structure. The platform consists of a PDMS chip with a Y-shaped microchannel and a glass substrate on which mouse hepatocytes are cultured. By the laminar flow effect, the zonation constructed in vivo liver is reproduced with media of different oxygen concentrations in the device. To evaluate the device, FEM simulation and an experiment for evaluation flow in the channel were carried out to determine the relationship between the flow rate and the diffusion region. Moreover, the mouse primary hepatocytes ware cultured using the device. As a result, it was confirmed that it is possible to change the concentration gradient by changing the flow rate, and the hepatocytes could be cultured successfully.

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We developed novel soft actuators using piezoelectric thin films. To realize low-cost fabrication method, we also developed a new transfer technique of piezoelectric thin films, which was deposited on temporary stainless steel substrate, to PDMS substrate by using wet etching process. By characterizing crystal structure and driving performance as actuators, we experimentally clarified that transferred Pb(Zr,Ti)O_3 (PZT) thin films have piezoelectric properties. This method might allow us to develop novel MEMS (micro-electro-mechanical systems) devices such as artificial muscle at low-cost fabrication in future.

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In this study, we have been developing a micro glucose sensor integrated-device for cell-based assays. Glucose is the energy source of living cells. Therefore, measurement of the glucose consumption of cells is very important in cell biology. In our previous research, an enzyme-fixed micro glucose sensor integrated to microfluidic device has been proposed to measure are cellular dynamics continuously. However, the sensor sensitivity is still insufficient to measure detail of cellular dynamics. The sensor sensitivity is required high sensitivity to measure detail of cellular dynamics. In this paper, we examined the basic performance such as the enzyme amount and flow velocity on the glucose sensor.

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Quadrupeds exhibit adaptive locomotion under real-world environment. Such locomotion is generated via the coordination between legs, i. e., interlimb coordination and is controlled by a neural network called central pattern generator (CPG). However, underlying mechanism remains elusive. To establish the design principle of highly adaptive quadruped locomotion, we propose a "TEGOTAE"-based CPG control that exploits vertical and horizontal ground reaction forces (GRFs) from environment. In this paper, we develop a quadruped robot with GRF sensing mechanism and verify the validity of proposed control scheme.

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Although numerous robots have been developed inspired by animal locomotion, they could not reproduce adaptive and resilient behavior of real animals. To tackle this problem, we adopted ophiuroids as our model. In our previous work, we focused on the locomotion of an ophiuroid whose arms were shortened or removed to investigate the inter-arm coordination mechanism, and proposed a decentralized control scheme on the basis of "TEGOTAE", a Japanese word that means reaction after the generation of some action. In this study, we proposed a decentralized control scheme that enables well-balanced coupling between inter- and intra-limb coordination by extending our previous control scheme. The validity of the proposed control scheme was confirmed via simulation.

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Although autonomous decentralized control could be the key to understand the mechanism of adaptive and resilient animal locomotion, its mechanism has not yet been clearly understood. To tackle this problem, we focused on an ophiuroid as our model and proposed a decentralized control scheme in which "TEGOTAE", a Japanese word meaning reaction after performing some action, was fully exploited. In this study, we examined the applicability of the proposed control scheme to other types of animal locomotion. We here focused on peristaltic locomotion of earthworms, and designed a decentralized control scheme on the basis of "TEGOTAE". We verified the validity of the proposed control scheme via simulation.

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It is well-known that a neural circuit in a spinal cord called central pattern generator (CPG) plays a crucial role to generate stable and adaptive bipedal walking. Although various CPG models have been proposed so far, the essential mechanism has not been clarified: neural connections in CPG and sensory feedback have been designed on ad-hoc basis. To reconsider the design principle of CPG model for bipedal walking, we extended our quadruped CPG, which fully exploits physical interaction yielded from local load sensing, to bipedal walking control, based on the phylogeny process. In this study, we developed a bipedal robot that has load sensors in the plantar area for experimental verification of our bipedal walking model.

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This paper discusses how autonomous mobile robots know the relative positions of others. We suggest the use of wireless communication modules for estimating the positions of others. The magnitude of the received signal strength indicator (RSSI) in wireless communication relates to the distance between the receiver and source. It offers a key to enabling position estimation by measuring the RSSI value around a robot with wireless modules. First, we propose a direction estimation method based only on comparison of RSSI values of multiple positions. Next, we develop the robot that has two XBee wireless communication modules mounted on the ends of the rotating arm. Finally, we evaluate the precision of the proposed method through some experiments using the robot. Experimental results indicate that the robot could estimate the rough direction of the target robot with the precision of approximately ±45 [deg].

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Legged animals, such as the mammals and arthropods, generate adaptive and pliably locomotion in various environments. They achieve this amazing ability through the coordination between their legs, i.e., interlimb coordination. However, the interlimb coordination mechanism still has not been explained clearly. To tackle this problem, we construct the following working hypothesis: interlimb coordination consists of two fundamental mechanisms underlying legged locomotion, i.e., "body support" and "propulsion". Based on the working hypothesis, we extend our interlimb coordination control, which was previously designed for quadruped locomotion, for various types of legged locomotion. In order to verify the extended model, we developed a multi-legged robot as a robotic platform.

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Snakes actively utilize terrain irregularities and move effectively by pushing their body against the scaffolds that they encounter. Clarifying the underlying mechanism will help develop robots that can work well in unstructured environments. In our previous work, we proposed a decentralized control scheme consisting of curvature derivative control and local pressure reflex, and demonstrated that our snake-like robot with the proposed scheme moved effectively by exploiting pegs. However, it still had a problem that the robot could not move effectively depending on the alignment of pegs. We here improved our previous scheme. In the improved scheme, reaction forces from environment are evaluated in real time and those beneficial for propulsion of the body are selectively exploited. The improved scheme could bring a breakthrough for achieving scaffold-based locomotion.

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This paper aims to search a possibility to realize multi-robot system, for example, movement in a flock without any global information. In the previous study, Mi-Nashi localization method has been proposed. Simply speaking, robots estimate the trajectory and revise it by transmitting the presumed position data with each other. However, there remains an unsettled question how it performs in the real world though the estimation method was well worked in the simulation. In the view of the real world demonstration, some problems will be expected to be seen; Conflicts in communication, fluctuation of strength of the radio wave, limitation of memory length, and so on. After solving these problems, we examine the validity of the proposed method through some experiments.

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This paper propose a self-assembly robot based on distributed control systems unlike centralized control systems. Our aim is to achieve self-assembly systems which adapt to environmental changes. We develop simple modules so that they behave phototaxis as a case study. These modules are equipped with led and sensor as output and input, vibration motor as heat, and perform like converter. Experimental results show that the developed modules can combine and convey their energies in response to environment changes.

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In this paper, we propose a lattice modular robot which is able to perform both binding and transformation on 2D plane using helical magnets. A helical magnet has a cylindrical shape with helically-arranged magnetic poles on its surface. Modules have a square shape when viewed from the top. Helical magnets are arranged on each sides of square. Modules can bind each other by attraction of each of helical magnets. In addition, helical magnets work as a linear actuator by rotating it. This enables a module sliding transformation from its neighbor modules to further its adjacent modules. There are problems of existing modular robots that unable binding and unable transformation because of mechanical interference and lack of space. This proposed modular robot realizes various self-reconfigurations through overcoming those problems.

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Animals show adaptive locomotion depending on their body, speed of travel, and an environment. In quadrupedal locomotion, a spine has an important role during interaction between an body and interaction. This paper focuses on stiffness of the spine, and develops simulator for a simple quadrupedal robot which has 3 degree of freedom (roll, pitch, and yaw), so as to discuss effects of stiffness of the spine for interlimb coordination. In this simulator, stiffness of the spine are changed, and each leg of the robot is controlled by decentralized autonomous control. Different stiffness shows different gaits, walk and trot in low speed locomotion.

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Lack of labor force due to aging is a serious social problem. However, practical solution is not presented. The authors have researched the robot system to complement the shortage of labor force. This paper verified the construction method of the mobile robot system for logistics in the marginal village proposed so far. Robotic system is constructed using some architectures. However, Architecture that are both robustness for social system and reliable functional solutions does not exist now. In addition, Conventional architecture cannot improve and practical use has not been proposed in parallel development. Developed mobile robot system performance can be continuously improved and it is designed as practical use. Report Having obtained the prospect of improving the robustness with respect to weather disturbances by changing the weight of each layer.

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Polystyrene mold used in full mold casting is usually machined by a CNC machine. On the other hand, an articulated industrial robot costs lower and can move more flexibly. Efficient machining will be accomplished by attaching a spindle motor with a ball end mill to the tip of the robot. A trajectory following control system based on CL (Cutter Location) data has been developed for a machining robot. In the system, the discrete trajectories at each sampling time are generated from position and orientation information in CL data made by post processor in CAM system. Many machining experiments were carried out using the machining robot incorporated with the controller, so that it was confirmed that the quality of machined surface of foamed polystyrene depended on machining conditions. In this paper, the effects of rotation speed of an end mill and small vibration control on quality of machined surface are compared.

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To solve structures of biomacromolecules is important for structure-based drug design as well as understanding of various biological processes. X-ray crystallography is one of the most popular methods for structure analysis of protein in atomic resolution. Sample exchange robots have been developed and implemented to protein crystallography beamlines in Photon Factory, KEK, for higher efficient experiments, remote-controlled experiments, and fully-automated experiments. In this paper, we proposed using a force and torque sensor installed at the sample exchange robot for stable operation. The sensor records various parameters of the robots' status when the tongs access sample cassettes in a liquid nitrogen Dewar. Distorted load distribution is caused by inclination of the cassette, miscalculation of the center of the cassette, mis-setting of the robot parameters, and other causes. In order to assure stable operation, the robots are appropriately re-calibrated according to the load distribution information.

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Most industrial robots use teaching/playback method based on the position/orientation of the robot end-effector. In order to realize the assembly task flexibly according to the contact force from the environment, force control methods have been studied. In this paper, we study control methods of direct teaching and playback of the robot arm during an insertion task. We compare the contact forces with the environment and the forces from the operator during teaching, and achieve a stable playback of the insertion task.

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The process of wakame seaweed is done manually by human hand. To reduce excessive labor on harvesting wakame seaweed, we have been proposing the machine to assist processing the salt-preserved wakame seaweed, cutting notch between wakame stem and leaf

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We are developing a autonomous robot system for power distribution line maintenance works. The robot system is multi agent system composed of 6 agents and 2 databases. The robot system reads the work procedure written in the task level, autonomously to perform the primary tasks. For example, "insertion of bolts" and "The tightening of the nut", etc. This time, we performed the mating of bolts and nuts using the remote control by joystick. We measured position and force when it is subjected to mating bolts and nuts. In addition, we examined how to implement to the robot arm on the basis of the experimental results.

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In this research, we deal with archery as the sport, and target on developing an archery robot in order to analyze the mechanism of tools, and realize archer's technique. As the third step, die new grasping unit that does not change bows position even if die fire and the finger unit that realize the allows bending vibration of human equivalent is developed. Results of experiment, these can attain die allows bending vibration of human equivalent. Additionally, it has reproducibility higher than him arts one.

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The objective of this study is to develop and analyze the compliance model of a vertical multi articulated manipulator PA-10. The proposed model estimates the tip deformation of the manipulator to consider the influence of the non-geometric errors and measurement errors. In this paper, we reveal the compliance characteristics in the 3D space using the compliance ellipses. To confirm the usefulness of the proposed compliance model, the verification experiments in which the tip compliance is measured are conducted under the 24 conditions and compared with the tip compliance ellipses which are computed from the compliance model. The results of the verification experiments showed that the compliance model can provide an estimated range which is enclosing the measured compliance.

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To help activity-of-daily-living (ADL) is important objectives for robots. So there are many kind of studies about ADL in the field of the robots. But most of robots cannot provide sufficient support with them, due to the limitation of dexterity of their own hand. We exemplify a humanoid HRP-4 and develop a hand extension for HRP-4. The hand can be attached to some robots by changing sockets. And the hand is programmed as RT-component on OpenRTM-aist, which is also used for controlling an HRP-4. The hand we developed has one degree of freedom and one pressure sensor on the finger. The sensor enables to control gripping force.

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In this study, we reported on a high sensitive 2-axial force sensor with cantilever structure for blood pressure pulse wave measurement. Our sensor consists of 2 strain sensors which were embedded in cantilever structure of elastic body. When the normal force is applied, cantilever structure bends. When the shear force applied, cantilever structure twists. Since 2 strain sensors are placed planar, we easily reduce the thickness of the cantilever structure. Therefore the cantilever structure deformed easily and the sensitivity of our sensor becomes higher. We measured the sensitivity of our sensor. The sensitivity of our sensor to forces in normal and shear directions were 0.89 V/N and 0.32 V/N. We measured blood pressure pulse wave and calculated the SNR (Signal to Noise Ratio) of blood pressure pulse wave. The SNR measured by our sensor in vertical and shear directions were 6.6 and 5.2.

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This paper presents the new method that calculate the plantar pressure distribution based on the brightness distribution of the continuous plantar image captured by the camera located under a transparent acrylic resin plate. To evaluate the proposed method, the comparison experiments are conducted with the hemisphere model that simulated a human heel. The measurement result by the proposed method and the pressure sensor while the model pushed down with the same vertical force are compared. The experimental results show that pressure distribution calculated by the proposed method are qualitatively similar to pressure distribution by the existing sensor. The intensity of brightness of the contacting area changes according to the pushed vertical force. The resolution of the camera that we use are three orders of magnitude higher than the existing sensor. The experimental results suggested the possibility of estimation of the high spatial resolution of the dynamic plantar pressure distribution.

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Hemiplegic patients often have reduced typing speed due to finger paralysis. Our motivation is to develop a device that enables their typing speed to increase. For this purpose, we developed a three-dimensional keyboard that reduces the distance that fingers move while typing. Our objective was to verify the best arrangement of the three-dimensional key for increasing typing speed. We hypothesized that typing speed will increase effectively when the keys are placed at the neutral posture of fingers. We analyzed finger motion speed and finger muscle fatigue when pressing the three-dimensional key. We found that finger motion speed was fastest when the finger is rather bending than neutral posture, and finger muscle fatigue was lowest when finger is rather extending than neutral posture. Finally, the optimal key arrangement that compatible high motion speed and low fatigue was indicated as the arrangement that was set to the neutral posture of finger.

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In this study, we reports on a glasses-mounted blood pressure pulse wave measurement device based on the arterial tonometry method for continuous measurement in daily life. In order to apply the arterial tonometry method to the superficial temporal artery of the head, we fabricated a glasses-mounted device with a positioning mechanism by 3D printer. We measured the blood pressure pulse wave during walking by the fabricated device and the conventional device in the wrist for comparison. The variation in systolic blood pressure measured by the conventional device and the fabricated device were 17.4 mmHg and 3.2 mmHg. Since the influence on the measurement by the body motion was reduced by the fabricated device, the variation in systolic blood pressure was suppressed.

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Recently, we have proposed a low-cost and highly reliable monitoring device which is called the MIMAMORI device for a monitoring system at a medical institute. The MIMAMORI device can detect dangerous situations, such as when a patient is at risk of rolling out of bed. In this paper, we detail the patient state classification algorithm using a deep neural network of the MIMAMORI device, and verify its practical applicability with a preliminary experiment.

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In aging societies, the burden of nursing care has become heavier and heavier. In order to reduce the burden by the introduction of robot technologies, a new prototype high-functionality nursing-care assistant robot named ROBEAR is developed. It has two human-type arms that are used to lift and move a patient from a bed to a wheelchair or to assist a patient to stand up. For realizing soft movement of the two arms, three kinds of force related sensors are employed on each aim. In the present paper, the outline of ROBEAR is explained, and the results of actual experiments on patient-transfer and standing assistance are reported.

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The paper describes that development of a prototype system for teaching foot cleaning self-care in diabetic patients for prevention of tinea pedis. The system consists of two cameras and black light lamps. In the system, the patients can easily confirm the areas where they cannot sweep away by watching the remained fluorescent image on the tablets, once they put their feet into the system during sitting. We also developed image analysis method for measurement of remained fluorescent area.

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We are developing a semi-autonomous robot system for power distribution line maintenance works. The robot system autonomously performs primary tasks, for example "Tight the nut" to reduce the load on operators. The system is multi agent system which constructs 5 agents and 3 databases. Operators control the robot arm remotely by joystick. We measure the position and force at the tip of a tool while screwing a nut for bolt fixed on the steel cross arm and tightening it remotely. We develop initiative of robot arm orbit which we want, from the measured results.

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Recently industrial robots are used for many purposes, especially as machining facilities. Many of grinding robots are controlled by using feedback of force. However, the force sensor used for force detection by means of strain gage will be damaged if a shock and big force should be applied. So, this laboratory has been researching with a method for grinding a target object into desired shape with force-sensorless feed-forward control. The dust made by grinding injures respiratory organs or eyes of worker. Therefore, this research aims to achieve construction of the robot system which can perform autonomously grinding. It is necessary to measure the unknown surface to decontaminate. This paper proposes a new recognition method to detect arbitrary shape using Bezier Curve and shows the result of grinding experiment using the method.

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To automate an assembling camshaft process(e.g. fixing a shaft to a jig, picking a cam piece, and fitting the piece on the shaft on the designated direction), a promising technique for manipulation of the cam piece is proposed. An end-effector for picking and fitting the cam piece is designed and prototyped to perform substantiative experiments of the technique for manipulation. The end-effector consists mainly of two neodymium magnets to pick and release the cam piece, and its configuration is produced by trial and error through preliminary experiments with careful attention to keep versatility for different type of cam pieces. In addition, a 2DOF robot manipulator is designed and prototyped to evaluate the performance of the end effector.

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This paper newly develops a small autonomous mobile manipulator that consists of a three-joint manipulator and four-wheeled omni-directional drive mechanisms. The manipulator enables to position control on the three dimensional space, and the mobile platform can move remaining its orientation straight and diagonal towards traveling direction, which can be realized by two-wheel drive or four-wheel drive. In this paper, we propose a simple and novel traveling control method so that the mobile robot is able to travel in a straight line on flat ground. This control strategy is based on the integral computation of a gyro sensor to modify the orientation of the robot during the traveling. In addition, we achieve that the mobile robot can climb on a slope of 20° inclined angle by changing the speed distribution between the four wheels. Finally, this paper concludes that the small autonomous mobile robot embedded with a three-joint manipulator can travel stably on irregular terrains.

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In recent years, various robots have been researched and developed. As a part of them, robots working in dangerous place for human beings are attracting attention. The dangerous places include the outdoor irregular ground or the narrow place mainly, so the robots need to have high moving ability. In addition, It also requires high operational ability as same as human. To satisfying these necessities, multi-legged robots are suitable. In this paper, we design a robot hand for visual inspection equipped with 3D force sensing. The designed hand is attached to the tip of legs of multi-legged robot. Furthermore evaluation of a prototype is reported.

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This study deals with sweeping algorithms of robotic vacuum cleaner appliances using machine learning. Firstly, the authors confirm whether learning of spiral is possible by preliminary experiment. Then, spiral movement is moved at random parameter and spiral movement is made by machine learning are evaluated by numerial simulation.

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Recently, the robot technology is rapidly expanding, together with the performance improvement of PCs and microcomputers. Generally, a PC is suitable for the information processing of sensors in which the amount of the data to be processed is large, whereas a microcomputer is suitable for real time processing such as motor control etc. Therefore, a controller for a robot system with multi-DOFs consists of one PC and multiple microcomputers. In such a case, the information transfer between the PC and microcomputers becomes a key point to develop a useful distributed controller. Especially, this paper discusses the kind of command and the amount of data that are transferred by a CAN communication, and describes the verification result that the basic performances satisfy the specifications as the robot controller. Simultaneous executions of motor control and the data transferred by the CAN communication, which is applied between a PC and multiple microcomputers, are confirmed through experiments by using a real robotic system.

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Wearable force feedback device enables us to dynamically interact with virtual object while moving in wide virtual space. We have developed wearable force feedback device with variable viscoelastic elements; pneumatic artificial muscles and MR brakes. These mechanical elements show quick response by feed-forward control and high power density. In this paper, we tackled on weight saving of the device, and measured basic property again. Afterward, we evaluated whether a subject can distinguish when rendered different frictional force or elastic force. The subject was rendered one of five grade force, and replied which grade that was. A percentage of correct answers were lower at rendering elastic force. This is because the reaction force was change with angular displacement. In addition, the percentage didn't change respect to fixed state and wearing state. The subject could recognize the difference in the size of the force though the device was loaded.

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We studied the effect of vibrotactile sensation from papers to find which frequency is the most comfortable for hand drawing. This is because hand's movement is guided by vibrotactile sensation that was generated between paper and pen. We conducted an experiment that includes 2 steps. First, we tested some paper's materials to find which paper has better vibrotactile sensation on drawing. We also analyzed the frequency of vibrotactile waves on papers and found the fundamental frequency from selected materials. The results shown that additional experiments for wider range of frequencies are needed to specify the comfortable.

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We focus on the relationship between shapes and tactile feelings. Human tactile feelings have bidirectional relation with exploratory movements and humans adjust touch motion according to tactile feeling. We have investigated tactile perception on curved surfaces. There is a curved surface that gives a comfortable feeling. In this paper, we measure skin deformation during touching curved or plane surfaces by using a high-speed camera. Result shows that a specific skin deformation is derived from curved surfaces. Relation between the specific skin deformation and the comfortable tactile feeling is discussed.

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Humanoid robots require a skin sensor that allows them to identify objects and to perform in-hand manipulation accurately. Current robots, however, are still unable to achieve the desired accuracy. To achieve such a task, this paper introduces a new design of a capacitive force sensor for the skin. Equipped with temperature sensitivity compensation and digital output. Although the sensor is intended for distributed contact sensing on the skin, it has a wide range of applications. The experiment conducted gave satisfying results, allowing the concept to be tested further to confirm its functionality.

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