Precise motion control without mechanical noises is a technical issue on the operations of research vessels and underwater vehicles in order to observe creatures in actual. As a solution for the problem, we pay attentions to bio-mechanisms of underwater creatures, especially undulately fins being used for attitude control. Bio-mechanisms of creatures are adapted to environment as a result of evolution. If the motor control mechanisms of the creatures can be introduced into underwater robots, there is a possibility to realize a high performance actuator. In this research, we have been trying to develop a fin actuator using an electroconductive polymer as an artificial muscle. In this paper, we describe a method of fabrication for bimorph actuator and the results of performance evaluation, and the developing fin actuator.

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This study develops a spherical motor driven by electromagnetic force. The motor is composed of a rotor and stator. The rotor has permanent magnets. The stator has electromagnets. The electromagnets are excited to rotate the rotor by the excitation pattern generated in a control PC. We confirmed that the spherical motor rotates in omnidirection by rotation experiments.

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For measuring the length of a Mckibben actuator, we have developed a flexible sensor by using conductive rubber. By measuring the change of electric resistance, the change of the expansion and contraction of the rubber is estimated. Higher accuracy is obtained by measuring the circumference displacement than measuring the axial displacement using this flexible sensor. We also propose a method to avoid the pretension since a flexible sensor may be damaged by the pretension in an initial state. The accuracy of the flexible sensor is confirmed by comparing the estimate values with true values.

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We have developed a new flexible medical instrument to enable surgical treatment in the deep and narrow internal operative field of patients. This instrument is equipped with a forceps on the tip of a flexible tube through a 3-DOF (degree-of-freedom) interference-free wire-driven joint developed for a surgical manipulator. This instrument is also equipped with a manual-operation interface to manipulate the forceps and the joint on the other end of the flexible tube. The forceps and the joint are linked with the manual-operation interface by a wire that is fed through the flexible tube. The opening angle of the forceps is 90 degrees, and 2-DOF bending angles of the joint are ±125.5 degrees and ±106.5 degrees by operation with the manual-operation interface. The reaction time from the start of operation to the opening movement of the forceps is 0.009 seconds, and reaction times from the start of operation to the 2-DOF bending movements of the joint are 0.017 seconds and 0.014 seconds.

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The authors developed CMTD (Curved Multi-Tube Device) and studied the system which performed puncture to the liver by machine control.CMTD, which consists of a straight outer needle and a curved inner needle, can revise the error that occurred during puncture. By the system, we detect the puncture angle of the needle during puncture by clicking points of needle on the ultrasound image as a sensor with somascope. We supposed PTCD(percutaneous transhepatic cholangiodrainage) as an environment, and we tested puncture to the silicon tube which simulated a bile duct using this system and studied the effectiveness of this.

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To release the surgeons from the task of controlling the view during laparoscopic surgery, several automatic laparoscope positioning robots have been developed. These systems, however, depend on simple heuristics and may not offer the appropriate view that the surgeon wants. In this paper, we fully analyze the positional relationship between the laparoscope and the surgical instrument during laparoscopic cholecystectomy simulation and then propose a new algorithm for automatic positioning of a laparoscope during surgery. To evaluate validity of the proposed algorithm, we develop an automatic laparoscope positioning system on which the algorithm is implemented, and then set up experiments, in which the surgeon uses the system to perform a laparoscopic cholecystectomy simulation in an in-vitro environment. The experimental results show that our algorithm has a performance equal to the case that the doctor operates a laparoscope.

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Vitreoretinal surgery requires extraordinary precision. However, the realization is not so easy, and only skillful surgeons can perform the vitreoretinal surgery. Therefore, we developed a microsurgical robotic system for vitreoretinal surgery so that many surgeons can perform vitreoretinal surgery easily and precisely. At first we conducted some experiments investigating positioning accuracy of manual procedure. Next we compare the positioning accuracy of developed system with manual procedure. And to determine whether this system can be used clinically or not, we evaluated the operability of manipulator using an eye ball of pig. In this paper, we describe the developed microsurgical robotic system for vitreoretinal surgery and the experimental results.

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The authors have developed a non-invasive ultrasound theragnostic system to decrease the strain of patients and medical doctors. The system we propose tracks and follows movement in an affected area -kidney stones here- while High-Intensity Focused Ultrasound (HIFU) is irradiated onto the area. In this paper, a framework of the non-invasive ultrasound theragnostic system is proposed and illustrated. Specifically, the concept of the system is proposed at first. Secondly, decomposing and reconstructing (structuring) of the functional requirements are discussed. Third, the constructed system, which is based on those structured functional requirements, is illustrated. Fourth, the result of the servoing experiments of the model stone is reported to confirm the effectiveness of the proposed construction methodology and constructed system.

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In robot-assisted orthopedic surgery system, rotational tools are often used because traditional industrial CAM can be applied to these systems. On the other hand, in case that a rotational cutting tool is used, non-working part of the cutting edge is likely to collide and damage soft tissue such as skin, tendon and patella. We developed a cutting tool equipped with a tool cover to cover a non-working part of the cutting edge to protect soft tissue in minimally invasive orthopedic surgery. In order to evaluate the cutting tool system, we performed a total knee arthroplasty with a cadaver. The experiment showed that the cutting tool system decreased the damage of soft tissue and the cutting tool system was effective.

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In Laparoscopic surgery, surgeons cannot use their own hand directory. Therefore, they retract an organ with a slender instrument called retractor. Current retractors do not have area enough to retract an organ gently. This paper proposes an assemblable mechanical retractor-hand that can be inserted through a trocar. The aim of this research is to design a practical assemblable hand by limiting its application to retracting. Previous work already reveals that assembling in the abdominal cavity is possible. However, assembling require skills of a surgeon. Therefore we propose new assembling sequence, "Single Trocar Assembling", that uses only one trocar. Experimental results verify that the hand can be assembled easily and withstand a force of 25N in a retracting experiment.

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A MRI compatible robotic gripper that has an ability to grasp an object in MRI environment has been designed. This gripper uses piezoelectric actuators with strain amplification mechanisms that provide lightweight, highly efficient, and large strain actuators. A method for designing the gripper considering the elasticity of the actuators and the structure is presented. The structure is designed based on reverse action tweezers. Using CAE software, the performance of the assembled gripper is examined in terms of displacement and force, then the size of the structure is determined. This paper introduces a prototype design for the robotic gripper with 7mm of the tip displacement.

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We have proposed a novel method to produce biological models using polyurethane elastomer, which has high photoelastic coefficient. And a method to analyze stress states on the model by circular polarized light method. In this paper, we propose stress measurement on biological model by reflection method, which is a stress measurement method using photoelastic effect. With this method, stress is measured in area wider than that of circular polarized light method and stress direction and magnitude cam be measured. The accuracy of reflection method is evaluated by tensile test using cylindrical model. And an application on artery model is verified experimentally. We could analyze stress states quantitatively on the model of cerebral artery. Consequently, it should be valuable for various applications not only surgical simulations but also hemodynamic studies and pathological studies.

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This paper describes an ultrasound-based real-time target tracking method for a renal stone treatment system using high intensity focused ultrasound (HIFU), because the target stone moves due to respiration, heartbeat, and so on. Especially, target shape in ultrasound image is deteriorated by cavitation bubble and debris of the target stone during HIFU treatment. This makes difficult to track the target stone, and furthermore it may fail. Therefore, a blob tracking method using target dynamic model independent of shape information is proposed. Moreover, Hough transform method is modified with convex hull algorithm to enhance tracking accuracy. Consequently, robust and accurate target tracking is performed well uninfluenced by HIFU-induced noises.

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Recently, Laparoscopic surgery is widely applied because of its minimal invasion. Ultrasonically activated scalpels(USADs) are widely used in laparoscopic surgery to incise and coagulate tissue simultaneously. However, it is difficult for surgeons to manipulate a USAD and approach to a target tissue because it has only a linear shape and limits the degree of freedom. To solve this problem, we developed the bending forceps with the small USAD on its tip. In this report, we proposed two types of control of tip-rotation for the developed forceps to achieve safe and easy operations for surgeons. One is the fixed posture control; and the other is the fixed position control. We simulated and compared those controls. As a result, we concluded that the fixed position control was more intuitive control than the fixed posture control.

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Accurate values of material parameters of human tissue are key elements in surgical robot system using an organ deformation model. However, it is generally difficult to determine the material values of human tissue to input into the model, because the material properties of human tissues are inherently uncertain because of their individual differences. In this work, we discussed the method for identifying the values of the material parameter of an organ model. This paper is concerned with developing a method using the Finite Element Method and the Extended Kalman Filter to identify the values of material parameters of an organ model. The effectiveness of the method was shown through physical experiment using a phantom. As a result of experiment, it was shown that the material parameters of the organ model were identified.

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This paper shows validation of viscoelastic and nonlinear physical model of liver. In vitro experiment using biomaterial in previous works shows the nonlinear response of force loaded on the needle and the velocity dependency of needle displacement where puncture occur. The physical models of the liver were analyzed under the same conditions of in vitro experiment in order to evaluate the model. From the result of validation experiment, the developed liver model reproduces the nonlinear response of force loaded on the needle and the velocity dependency of needle displacement where puncture occur.

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In this paper, a development of an open control software for surgical robots is presented. With the recent development of advanced medical devices, the connectivity with these devices such as a navigation system or medical imaging devices became important for surgical robots. Also, the safety issue is essential for the control software of medical robots. From these perspectives, we are developing the open control software for overcome these challenges.

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A new robotic system named "Hyper Finger" for remote minimally invasive surgery of deep organs has been developed. In this report we developed a new manipulator mechanism for Hyper Finger that has been reduced wire friction and interference between each joint. In addition, we developed compensation algorithm of driving resistance, so that the position trailing ability has been improved considerably. Finally, we demonstrated with a pig liver that improved Hyper-Finger can approach to the reverse side of a organ and suture a wound there.

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Endoscopic treatment is one of the minimally invasive surgical procedures. With this procedure, a doctor can excise the cancer tumor in the stomach without having to perform a laparatomy. However, currently there is limitation for doing treatment in the narrow digestive tract and as such; a new tool to aid the doctor in performing the endoscopic treatment is sought. In light of this, we propose and have developed the new tool, which can be used in conjunction with the ESD, needed in the endoscopic treatment. This tool aims to improve efficiency of the treatment by holding the mucous membrane in the inner wall of the stomach that has a soft structure while the ESD is being performed and removing the excised part after the cut. To test the utility of the tool, the developed prototype of the tool was used by a certified surgeon on a pig's stomach and the tool's effectiveness was verified.

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In this research, we developed a variable volume balloon sensor for minimally invasive surgery. But in the process of manufacturing the balloon sensors, generation of individual difference of each balloon characteristic is inevitable. To solve this problem, in this paper, we propose a initialization method of balloon sensors. The method is consisted of two processes. One is balloon material stabilization. Molecules of Silicone are fatigued by cyclic stress, so several times balloon construction by the auto pressure controller is effective. Another is balloon sensor value calibration. Adequate zero point of balloon sensor value is able to be estimated by balloon characteristic. We did an experiment of the method of balloon initialization, and result shows effectiveness of balloon stabilization and calibration.

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To make a natural physical interaction the entrainment between human and robot motions accomplishes an important role. From this view point we proposed to use neural oscillators for human-robot handshaking. However there is a drawback of the method. In this paper we propose a design method of dynamics to generate synchronization and entrainment in human-robot handshaking instead of the neural oscillators. We utilize a polynomial design of the nonlinear dynamics and extend the method to synchronization based control of human-robot interaction. The validity of the design method is examined by the experiments of human-robot handshaking.

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A power-assisted cart for stair-climbing with planetary wheels is proposed. The planetary wheel is composed of planetary arm whose rotation is power-assisted by a motor and free wheels on the ends of planetary arm. With proportional power-assist control algorithm which commands motor by proportional torque to sensed drag force by human, reduction of the drug force up to 30% is observed. Speed of stair-climbing become faster for higher power-assist gain. So it is considered that the operator controls horizontal motion while vertical motion is assisted by the motor. Two planetary wheels with different dimensions are experimentally compared and better design or power-assist control is selected.

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This paper presents the development of a novel human-robot cooperative task system, which consists of a proposed 3D positional deflection measurement device and an ordinary robot motion controller. The proposed device and the motion control strategy, which is called an inherent dynamics based control, enable a human operator to interact with a robot intuitively. Relative motion deflection (i.e., relative positional deflection) between the human operator and the robot is detected by the proposed measurement device. The robot motion controller generates motion command in proportion to the detected motion deflection. To confirm the performance of the proposed system, the human-robot cooperative interaction experiment is carried out. The experimental results show that the proposed system is effective for the human-robot dynamical interaction.

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This paper presents a new control methodology for the mobile robot wherein the autonomous and man-machine-cooperative controls are combined. In the proposed control scheme, the 'autonomous control' and the 'man-machine-cooperative control' are designed by the time-state control and impedance control, respectively. The former tries to reduce the deviation from the guideline of the robot, the later, on the other hand, generates the power to assist the operator's skill. Furthermore, the composing method of the two different controls are discused. Finally, some experimental results are shown to demonstraight the usefulness of the proposed strategy.

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This paper presents a method of evaluation of reliability of particle used for the particle filter using gaussian mixture model (GMM) which is made from the relation of the the observation obtained from the sensor and the state that is the presumption object. The particle filter is known to be effective for tracking people. However, when we evaluate reliability of particle, particle filter often needs a complex, nonlinear transformation between the amount of the state and the observation. Then, a proposal method is evaluation reliability of particle directly from the GMM. So, there are not needed a complex, nonlinear transformation. Moreover, we propose a particle filter with multiple prediciton models wherein the prediction model is selected according to the likelihood value of each prediction model. Furthermore, the proposed method is applied to the carrying task using mobile robot and the effectiveness is verified.

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Recently, the aging problem is attracting great attention in society of Japan. One of the important technologies to overcome this problem is a development of power assist system which is able to assist the elder or disabled person in various situations. In the previous works, a force sensor was mainly adopted as the interface between machine and human operator. In addition, the EMG sensor is expected to play an important role in the man-machine interface since it can detect the human intention earlier than the force sensor. This paper presents a new power assist system wherein both of the EMG and force sensors are exploited and appropriately switched according to the operating situation. The usefulness of the proposed scheme is demonstrated through some experiments.

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In this paper, the development of a power assist robot system and control strategy using a surface electromyogram signal is presented. The proposed system enables a human operator to cooperate with a robot intuitively. Robot motion is controlled by a proposed controller which generates motion command composed of an estimated force signal obtained from the measured surface EMG signal and a direction vector of the operator's motion detected by a motion detecting device. The experimental results show that the proposed control system is effective for the human-robot cooperative interaction.

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In automobile production lines, there are many operations by not only autonomous machinery as industrial robots but also man-machine cooperative systems as power-assist systems. In this case, efficient mode switching from machine-oriented operation to human-oriented operation is important. This paper presents a new mode switching control method from the automatic mode to the manual mode on the basis of position based impedance control. This method proposes the smooth mode switching compensator whose control input is continuous at the switching time. The effectiveness of the proposed method is verified experimentally.

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Joysticks are well-known input devices to control multi-link manipulators. In order to make a dexterous control of manipulators, operational skills should be obtained through training. This paper presents a new gesture interface for controlling manipulators. The features of the proposed method are contactless and instinctive. No equipment is required to wear since the entire system is composed of two infrared cameras and a control unit. The cameras capture three dimension movements of operator's hands. Operators can indicate position or direction of the end effector of a manipulator with the movement of their hands. Some experiments were conducted to show the usefulness of the interface. The results showed that the manipulator was smoothly controlled.

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Synchronous motion is one of the important ability for the co-operation work. This report, we proposed three techniques for synchronous trajectory generation PLL(Phase Locked Loop), fourier series approximation and wavelet transformation. PLL technique achieves the phase synchronization with an arbitrary cyclic motion, like as human walking. Fourier series approximation of target trajectory allows us description of wide variety cyclic motion for the robot. And wavelet transformation sets the frequency of target trajectory based on an arbitrary cyclic motion. More over, we can select the synchronous frequency from human movement with multiple cycles by wavelet transfromation. The experiment of synchronization with 3-DOF manipulator and human demonstrator are carried out. As a result, we confirm synchronous performance and the effectiveness of proposed method.

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This paper deals with a force sensing mechanism composed of a force sensor device and an end-effector of shell-shape. Since the end-effector plays a role of an outer shell, force can be sensed at any positions on whole body. The sensor has an ability to calculate the position of a contact point without any sensor array. Based on the ability, this study applies the force sensing mechanism as a haptic interface similar to a touch panel. Experimental results show the validity of the proposed method.

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This paper presents a behavior labeling algorithm for time-series data, extracted using home sensors. In the previous work, we proposed a time-series data clustering method based on Hidden Markov Models (HMMs). However, change points of behaviors are not clearly segmented in our former method and short length behaviors tend to be misrecognized. In this paper, we propose a novel behavior labeling algorithm by introducing Singular Spectrum Transformation (SST) to detect change-points robustly. This algorithm enables more precise behavior labeling because of clear change-point detection.

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Recently, the demand for a man-machine cooperative system is rapidly growing in industrial fields. To meet this demand, the human model has been required to design the suitable assist controller in the man-machine cooperative system. We have already presented a human behavior model based on the hybrid system and variable impedance controller applying this model.In this paper, we propose grouping method of workers using Hidden Markov Model (HMM) and confirm the usefulness of this method using variable impedance parameters. At first, we construct HMM to each worker. Then, the grouping of workers will be done used constructed models. Finally, we compare the grouping result with designed variable impedance parameters and confirm the usefulness of the grouping of workers.

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This paper describes an algorithm of behavior labeling and anomaly detection for elderly people living alone. In order to grasp the person's life pattern, we equip some pyroelectric sensors into the house and measure the person's movement data all the time. From those sequential data, we extract two kinds of information, time and duration of each behavior, and make the system calculate two-dimensional probabilistic density function of them. By using this function, the system classifies behavior labels and detects anomaly. In addition to these two kinds of information, we consider another kind of informaion, behavior transition patterns, at anomaly detection. Here, we assume local anomaly and global anomaly. The former means the rare behaviors and the latter means the changes of life pattern. The algorithm is confirmed through the experiment on about 400 days real behavior data.

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This paper describes a novel wireless sensor network system that provides both functions of sensor value transmission and sensor localization. ZigBee technology is utilized as wireless network protocol in our system because of its advantages in terms of power consumption and easiness of self-organizing mesh network. For location estimation, Received Signal Strength Indicator (RSSI) is leveraged and a robust grid based sensor localization algorithm is proposed. A testbed location aware ZigBee-based system is successfully evaluated in terms of its performance of sensor value transmission and sensor localization functions.

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These days, the Internet and mobile networks are actively utilized, and a lot of data such as moving images and voices is constantly exchanged on a world-wide scale. Such physical communication as a handshake and a hug that is very important for humans is expected to further be installed to indirect communication via machines or communication channels, but it is still limited to research. This report discusses a generic framework in which persons at different places sophisticatedly communicate physical information by machines. Note the following two approaches: First, we derive system dynamics by minimizing the total energy composed of mechanical energy and constraints necessary for desired motions. Second, we enhance our framework for a module-based dynamical neural network model. This report also argues that our top-down method is more effective than a conventional bottom-up method.

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Relationship between workers is an important information the manager needs to know by examining the worker's comfort level in an office environment. In this paper, visualization method of the relationship between workers is proposed based on the physical distance established among workers in an office throughout a day. The validity of the visualized relationships obtained by the proposed system is confirmed by comparing its results with that from self-evaluation questionnaires about a worker's strength of relationship with their co-workers.

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This study deals with harnessing for a quadruped robot toward seeing-eye dog robot. The control system is composed of two blocks: First one is spontaneous locomotion control system that is a oscillator network with phase-resetting. And the other is recognition system for human-machine interface that is a neural network to distinguish commanded motion pattern or harnessing pattern from human. Efficiency of the proposed control system is verified through numerical simulations and hardware experiments.

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In this paper, we proposed the soft skin design method of the human symbiotic robot arm which realizes the collision safety, assuming worst collision case including out-of-control mode of robot. Estimating the collision safety at the each position of robot arm, this method reduces the redundant safety, and so realizes the light and small shape.First using the HIC (Head Injury Criteria) and injury risk curve which are driven in the automotive safety, we set the safety criteria for human symbiotic robot. Next, we arrange the impact parameters which are conditions in the human-robot collision, and describe the important parameters to realize the light and small shape. Finally, citing human symbiotic robot "TWENDY-ONE" as the example, we apply the proposed method to TWENDY-ONE, and confirm the effectiveness in the shape and weight.

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Recently, the demand for the nuclear reactor equipment has risen because of the demand for energy. Therefore, the demand for climbing wall robot that works in place of the person has risen further in the height and the hazardous area. However, A difficult problem hasn't solved that the magnetic adsorption power remarkable decreases on any ruggedness such as the welding parts and rivets on the iron structure. This problem has disturbed the development of climbing wall robot. Then, the development of a new mechanism "using the magnetic adsorption power" has been advanced. This report shows the development of climbing wall robot on the ruggedness by using new omni disc that makes the best use of the feature of magnet adsorption.

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A method for transporting a large-scale polygonal prism by a small robot is proposed. To achieve the operation by a small robot, a new motion control considering the limitation of manipulation area and the sensing devices is required. Tumbling operation is one of good transporting method for controlling a large-scale or heavy object. We implement a balance control technique with the weight of the robot to the object rotation. The proposed method is implemented to a small robot "ASTERISK" and the effectiveness is confirmed.

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Recently, cleaning robots for domestic use have been actively developed. In our past studies, we introduced a new sweeping algorithm for cleaning robots, and verified its efficiency on a simulator. In this report, we mount the algorithm on a real robot, to compare the performance with the simulation result.

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In recent years, an increase of the senior citizen is regarded as social problem. Therefore, robots that assist them in an indoor environment are expected. In this research, the autonomous robot system is developed for table transportation because the table is frequently transported. In the developed system, the mobile robot which equipped with the jack moves under the table, lifts up the bottom side with the jack, and transports it. In this strategy, if the robot can hold around the center of gravity of the table, the one table can be carried by one robot. This paper describes the method to recognize the table position by using SOKUIKI sensor, detect the center of gravity and adjust the lifts up position. Experimental results on automatic transportation of the table are also discussed.

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This paper investigates multiple mobile robots coordinating with each other under a potential collision situation. The system considered consists of three wheeled mobile robots in which one of them serves as a leader agent and the rest follower agents. These robots are to collaboratively transport a large object. Uniqueness of our approach is mainly seen in the follower agents. Unlike conventional approaches, the followers in our method do not need to know the intention of the leader, e.g., where to go, in an explicit manner. Instead, the followers will assist the leader to accomplish the task as its own local task optimization. The efficacy of the proposed method is verified through simulation and experiments.

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In this paper, we explain the proposed Central Pattern Generator (CPG) network with independent controllability. The network is comprised of some CPGs and one Rethm Generator (RG). Each CPG and RG is represented by the Van der Pol equation. In order to verify the effectiveness of our proposed CPG network, the network is applied to a generator for an alternating tripod gait, and is implemented to a 3D model of the stick insect. A walking speed by stepping out of the model can be freely controlled by external signals, because the amplitude and the period of each output signal of the CPG can be independently controlled, keeping the value of the phase difference between CPGs.

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In this paper, we have aimed to enable a steady fast by change the program and the hardware of an autonomous quadruped robot walking and turn and to do the navigation.At that time, the one that the addition and the deletion of the program can be easily done without using a complex control method.This time, it aims at the stability walking in the rough way in this research for the expansion of the navigation environment in the autonomous quadruped robot.And, the stability walking with CPU that the reflex is used and the performance is inferior is achieved.Posture by the reactive behavior in the slope is controlled for that. In addition, the walking experiment on the slope where the postural control is done is considered about the stability walking on the doing slope.

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New leg-wheel hybrid locomotion on the rough terrain is proposed for a hexapod robot. The proposed leg-wheel hybrid locomotion is realized by the continuous transition movement between the wheeled and legged locomotion. In the basic posture, the robot is supported by the three legs and moves by using their wheels on the flat plane. When the robot senses an obstacle, the support and the swing legs change each other like a tripod gait with oval orbit to overleap the obstacle. The experimental results of all combinations of four fundamental steps show the effectiveness of our method.

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A working six-legged robot which can switch three modes for locomotion and manipulation is developed. In six-leg mode, the robot walks using six legs fast and stably by omni-directional tripod gait. In horizontal four-leg two-arm mode, four legs are used for locomotion and two legs for manipulation with its body horizontal to the ground. This mode enables the robot to manipulate objects using the front legs at low level, while supporting the body using the four legs stably. In vertical four-leg two-arm mode, the robot stands up. Four legs are used for locomotion and two legs for manipulation with its body vertical to the ground. This mode enables the robot to manipulate objects using the upper legs at higher level. In this way this robot has high mobility and manipulation ability. Omni-directional tripod gait in six-leg mode by teleoperation, dual arm manipulation in both two-arm modes by teleoperation and transitions between the three modes are implemented and tested.

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Time optimal control method for quadruped walking robots is developed and installed into a practical robot system. Swinging leg is modeled as a two link manipulator whose time optimal control theory has already been established by Bobrow. However, in legged robot systems, supporting legs support their body weight, and the reaction forces from its ground must be inside of their friction corn. Moreover, the ZMP(zero moment point) of the robot is constrained for stable walk. Therefore, time optimal control inputs must be designed considering these constraints. SONY ERS-7 is used as a quadruped walking robot and a fundamental experiment is done. From the experimental results, the effectiveness of the developed control algorithm is verified.

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This paper discusses the design of terrain-adaptive sole mechanism for multi-legged robots that walk on uneven terrain. To improve stability on irregular ground, the sole mechanism should have following two functions: (1) adaptability to the shape of ground, (2) shape-locking function after landing. To realize above with compact and light weight structure, the mechanisms with passive components are discussed, and the sole mechanism for quadruped walking robot TITAN VIII is developed. To measure the effective support area of the developed sole mechanism and to examine the effect, experiments were done. Through the experiments, the effectiveness of the developed sole mechanism was confirmed.

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