A silkworm makes flexible structure objects called a cocoon, such as a dome and a plane, by spinning a material like a fiber. Moreover, he moves as his mouth draws "8 of a number". Even if it sees this mechanism from the field of robotics, it is interesting. The method of making a cocoon is considered effective method as the new creation method of a structure. This research is advancing examination about creation of the adjustable surface in the space as the silkworm may do by using industrial-use robot, six axis sense of force sensor, and a spinning apparatus that imitates silkworm's cocooning mechanism and develops.

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The purpose of our research is to study the effects of a circular arc foot for a biped. The biped is planar and is composed of five links. Prismatic knee joints are employed to avoid the foot clearance problem. The ankle is not actuated then the robot is underactuated in single support phase. A geometric evolution of the biped configuration is controlled, instead of a temporal evolution. The input-output linearization with a PD control law and a feed forward compensation is used for geometric tracking. The temporal evolution is analyzed using Poincare map. The map is given by an analytic expression based on the angular momentum around the contact point. As a result, the radius of the circular arc foot affects to stability of walking, and speed of convergence decreases when the radius increases. Moreover a basin of attraction is broadened by choosing larger radius among the stable cyclic motion. Finally we discuss relationships of stability properties between the controlled system and passive dynamic walking.

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This paper investigates the roles of passive knee-joints in dynamic biped locomotion systems from the viewpoint of mechanical energy cycle. We introduce two planar biped walking models for analyses; one is with semicircular feet and the other is with flat feet. Viscosity at knee-joint is considered as a function to distribute mechanical energy dissipation and its effect on walking speed is numerically investigated. The analysis results and properties of the two models are compared, and the importance of mechanical energy dissipation in dynamic biped locomotion is discussed.

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The authors have clarified the mechanisms and importance of semicircular feet on dynamic biped locomotion. This paper then investigates the effect of asymmetric shape of semicircular feet on biped walking speed. The rolling effect acts as the virtual ankle-joint torque during the stance phase; the heel-side effect propels the robot's center of mass (CoM) forward during the first-half of cycle, whereas the toe-side effect forces CoM backward during the second-half of cycle. The feet on the other hand reduce energy-dissipation caused by heel-strikes at instants of transition. These properties can be adjusted by changing the foot radius. The question then yields of which effect is more crucial for gait generation. Underactuated virtual passive dynamic walking is considered to generate a biped gait and its parametric studies are performed to clarify the mechanisms of semicircular feet with various foot radius.

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This paper investigates dynamic bipedal gait and its stability from the mechanical energy balance point of view. The equilibrium point at impact in a dynamic gait is uniquely determined by the two conditions; one is maintaining the restored mechanical energy constant, the other is to settle the relative hip-joint angle to the desired value. The equilibrium point determined by these conditions is always asymptotically stable and this is shown by a simple recurrence formula of the pre-impact kinetic energy. The validity of our method is numerically confirmed via gait generation by virtual passive dynamic walking.

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This paper proposes a foot shape design to enhance stability of passive dynamic walk, which constrains fall down phenomenon. We divided the effect into lateral plane and sagittal plane and designed to effect as constraint to each plane. In lateral plane, constraining of swing from side to side is needed. In sagittal plane, stability of walk is kept by constraining fall down phenomenon by a constrainer attached top of the foot at the support leg. We show that a constraining effect realized by foot shape is effective for a walk by comparison with an arctic foot shape. By this mechanism, we describe the possibility of introducing an energy-efficient controller onto this configuration, which controls the constraining effect by changing ankle angle.

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We investigated relation between walking-efficiency and leg shape using passive dynamic walking simulator on lateral plane. The biped robot with circular foot has 4 D.O.F. Mass on waist was existed and CoG of each legs can be moved. Joints with virtual spring-damper model generate reaction force when angle of joints rotates more than desired angle. Five kinds of leg shape on limit cycle were searched by Genetic Algorithm. These bipedal robots were compared in term of kinetic energy and migration distance. We discuss about a design method of leg shape.

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We select a three-legged robot to study passive walk. The robot consists of one leg (a knee joint and an ankle joint) and one pair of crutches. The crutches part and the leg part are linked by a hip joint. Two walking robots that the knee joint or the hip joint is permitted free rotation are designed. The lower leg is equipped with a solenoid magnet which fixes the knee joint straight. The hip joint shaft and a DC-servomotor are connected by an electromagnetic clutch. The robot behavior is passive while the robot is supported by its crutches. Referenced swing trajectory is generated by a planar four-link model simulation. The walking pattern applies to the actual two crutches-type walking robots on level ground.

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We select a three-legged robot to study passive walk. The robot consists of one leg (a knee joint and an ankle joint) and one pair of crutches. The crutch tips are passive joint. Therefore the robot behavior is passive while the robot is supported by its crutches. The angular velocity at the beginning of the crutches support phase decides a crutch tip trajectory throughout that phase. This research deals with a planar four-link model to simulate joint angle trajectories for crutches support phase and to generate a proper swing leg pattern. The walking pattern applies to the actual crutches-type walking robot on level ground.

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This paper presents passive clynam i c walking with e].astic energy. We propose a new type of passive dynamic walking robot by adding elastic materials such as spring or rubber between a supporting leg and a swing leg of the robot. By utilizing restoring force of sprmg or rubber, we can make the passive dynamic walking robot easily walk since the angle of the swing leg is restricted. In this paper, we firstly derive dynamics of the passive walking robot with elastic energy. iNext, we show the effectiveness of adding elastic energy by computer simulation. Finally, we make the a(ltual passive walking robot with elastic energy and carry out walking experirrienits.

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Recently, it has been widely recognized that control and mechanical systems cannot be designed separately due to their tight interdependency. However, there still leaves much to be understood about how well-balanced coupling between control and mechanical systems can be achieved. Therefore, as an initial step toward this goal, this study intensively discusses the effect of the intrinsic dynamics of a robot's body on the resulting behavior, in the hope that mechanical systems appropriately designed will allow us to significantly reduce the complexity of control algorithm required as well as to increase the robustness against the environmental perturbation. More precisely, this paper deals with the adaptive selection between passive dynamic walking and running, particularly focusing on the body dynamics properties.

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A model of a passive-dynamic robot which is hypothesized to be capable of walking and running is presented. This model has been selected to match closely with a physical robot currently in construction, for the purpose of furthering the state-of-the-art in legged machines which locomote efficiently based on passive-dynamic principles. A novel actuator called the Variable Stiffness Series Elastic Actuator (VSSEA) is also introduced. Its design and advantages are briefly discussed.

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The restoration of mechanical energy lost during the collision between a leg and the ground is requisite for a steady and continuous gait. One principle to do this is the parametric excitation. Recently, Asano et a!. applied this principle to a biped robot with telescopic legs, and succeeded in generating a sustainable biped gait in a computer simulation. In this paper, we deal with a model of a biped robot that has semicircular feet and actuated knees. Though this robot has no actuator at the hip, knee actuators can sustain gait by parametric excitation. We first verify that an actuated knee can cause parametric excitation and then show by computer simulation that the proposed biped robot can walk continuously with actuated knees only.

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Recently, it has been widely recognized that control and mechanical systems cannot be designed separately due to their tight interdependency. However, there still leaves much to be understood about 1) how the relationship between control and mechanical systems should be; and 2) what does the "well- balanced coupling" between these two systems bring to resulting behavior? In light of these facts, as an initial step toward this goal, this study intensively discusses the coupling from the view point of the "temporal" contribution of control and mechanical systems to the resulting behavior. To this end, this study proposes a pulsed-CPG that allows us to change the brain-body interaction adaptively according to the situation encountered. In order to verify the feasibility of our proposed method, we implement the pulsed-CPG to a walking biped as a practical example. Preliminary results support that discrete control strategy by using a pulsed-CPG, which effectively exploits diversity of motion trajectory, enables to enhance the robustness against external perturbation.

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This paper describes a new design of a 3D anthropomorphic biped walker whose joints are driven by pneumatic artificial muscles antagonistically. First, a ballistic motion controller is derived for walking. Then, 3D motion of the robot is divided into sub-spaces so that its motion is analyzed in each space: sagittal, frontal, and horizontal spaces. The control parameters are investigated so that the robot can walk stabily.

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One of the challeging issues of biped robot study is to develop a robot that can not only walk, but run and jump. This paper describes new design of a biped robot that can walk, run, and jump. We adopted anthropomorphic open joints and antagonistic pneumatic drive. Preliminary experiments are conducted to demonstrate the ability of the developed robot.

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We are interesting of control 2-link-i-motor mechanism for locmotion. The locomotion of 2-link-i-motor mechanism is called "Dynamic walking by a link rotaion". We improved a control way and the robot can move even if initial condition is different. Then we realized 5 step locomotion continusly with a real machine. We report about the improved control way and the results of experiment.

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We designed and developed a quasi-passive dynamic walking robot with swinging torso, and we confirmed flat plane walking as well as slope climbing by experiments. We analyzed walking condition and succeeded slope climbing of variable inclination angle. Then, we discussed the estimation algorithm of slope inclination angle without using inclination angle sensor. Next, we experimentally realized dynamic walking where inertial force was considered. From the heuristic searches by changing swinging period of torso, we found several patterns in the results. They were compared with walking speed and the walking pitch. Then we discussed the walking condition depending on the swinging of the torso, including the change of walking direction.

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We designed and developed an ankle-driven type of quasi-passive dynamic walking machine. Then we modeled the machine by paying attention to the double stance phase for accurate analysis of realistic motion. And we used the method of penalty function to formulate motion equation. We succeeded to change the walking speed of ankle-driven walking machine by changing kick torque as well as brake torque. We analyzed the mechanism and confirmed by computer simulation. We discussed the validity of brake torque from the energy point of view s well as the stability of walking.

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Passive walking can be regarded as a physical phenomenon generated by the hybrid system, which consists of continuous dynamics of leg-swing motion and discrete event of leg exchange. Passive walking can exhibit a stable limit cycle. In this paper, we improve the dynamics of leg-swing motion by the shape of foot. Passive walker could stably walk on irregular terrain.

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In this paper, we consider an effect of a foot shape that is expressed by a convex function on the passive dynamic walking. First we explain how to parameterize the foot shape. We determine a foot shape by using second order Bezie curve, because second order Bezie curve is easy to control a form. Secondly we realize the passive dynamic walking on a shallow slope with a biped walking robot that has a foot shape determined by second order Bezie curve and show an effect of a change of the foot shape. Finally we optimize the foot shape by moving the control point of second order Bezie curve in a parameter region.

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The development of an oscillator controller for a bipedal robot with antagonistic pairs of pneumatic actuators is reported. Periodic motions of the legs switch between the swinging and supporting stages based on the phase of the oscillators. The oscillators receive touch sensor signals at the end of the legs as feedback when the leg touches the ground and compose a steady limit cycle of the total periodic dynamics of bipedal locomotion. The effectiveness and performance of the proposed controller were evaluated with numerical simulations and experiments with the hardware.

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We constructed a snake-like swimming robot using IPMC actuator/sensor, and verified swimming motion based on numerical simulations and experiments. In this paper, we consider the autonomous locomotion, and verify the realization of swimming motion by feedback of the sensor signal. The efficiency of the autonomous locomotion is investigated, and experimental results are demonstrated.

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Human interactive robot RI-MAN, developed by us, has so far used soft areal tactile sensors with 15 ms sampling period. This period is not satisfactory for realizing smooth sensor feedback response. In the current paper, we report our new tactile sensor with improved sensitivity and 1 ms sampling period, as well as its experimental results.

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Ionic polymer-metal composite (IPMC) is promising material in biomedical applications, since IPMC is soft and flexible, leading to the safety of the device itself. The purpose of this study is to investigate the biocompatibility of IPMC by in vitro experiment, in order to evaluate the applicability to biomedical field. Embryo cell of cynops pyrrhogaster could be cultured around IPMC films. Colony-forming test using Chinese hamster lung fibroblast cell shows high cytotoxicity of IPMC. Further tests are necessary to investigate the cause of cytotoxicity of IPMC. IPMC actuators immersed in medium for 7 to 13 weeks could show bending response driven by a rectangular wave and a sin wave.

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In previous work, we developed a high compliant robot consisting of McKibben actuators and PET(polyethylene terephthalate) plate. The robot was cord shaped, soft bodied to achieve biomimetic motion. And we confirmed the fundamental traveling characteristics on ground, in water and in curvature narrow space. In this paper, conductive resin film was formed on the compliant robot. Using the film, two functional controls which improved the safety around the robot were invented. One is path width estimation control, and the other is force control. Using former function, the robot detects the width of path before robot traveling. By later function, appropriate drive condition can be maintained for change of path width during robot traveling. Experiments of both functions were carried out, and high effectiveness was recognized.

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We propose a method for using surgeon's biological information to evaluate the surgeon's stress in his/her using a surgical assistant system. We focused on saliva and acceleration plethysmogram as the surgeon's biological information. The stress was measured by analyzing cortisol, alpha-amylase, and total protein in saliva, and we analyzed the acceleration plethysmogram variability as the indexes of autonomic nervous activity, those were coefficient of variance of the a-a interval and low-frequency band [0.02-0.15Hz] power spectrum (LF), high-frequency band[0.15-0.5Hz] power spectrum (HF), the ratio of LF to HF (LF/HF). To validate the effectiveness of the proposed method, we conducted a laparoscopic cholecystectomy simulation. In conclusion, we confirmed our method had an ability to objectively evaluate the surgeon's stress during surgery.

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We developed a medical hydraulic linear actuator for surgical assistant robotic systems. This actuator is driven by hydraulic pressure, and is disposable, and can be sterilized. It mainly consists of a polycarbonate cylinder with a diameter of 10mm and the initial length of 235mm, which elongates to the final length of 360mm. The actuator has the capability of generating forces over 2kgf and its weight is approximately 30g. We will apply this actuator to a laparoscope manipulator using parallel mechanism.

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Percutaneus needle puncture is minimally invasive and presents many advantages to the patients such as little pain, small scarring, and quick recovery. Surgeon is required to place the tip of a needle at a tumor precisely. However, even for expert surgeons it is not easy because of the needle deflection. The deflection depends on the needle shape that differs from maker to maker. The goal of our study is to estimate the main factor of needle deflections. Thus, we measured needle insertion trajectory by using three-type of needles for a tissue phantom. To estimate the main factor, we use a multivariate technique.

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Recently, the minimally invasive surgery attracts attention. And some surgical robots for the minimally invasive surgery are developed. In the abdominal cavity, it requires task complexity, so it takes a multi-DOF manipulator to do. It is a problem to multi-DOF manipulator to focus on end position. In this paper, it aims at development of Five-degree master-slave manipulator with closed loop structure. To make closed loop structure, it increases joint, so kinematics of manipulator complexify. To solve kinematics analyzes the characteristic of manipulator, and bilateral control is proposed to apply the characteristic. And manipulator and proposed method is effective by demonstration.

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Laparoscopic surgery is minimally invasive surgery and receives worldwide attention recently. But it requires surgeon a high skill under the hole constrain during the surgery. Our laboratory had developed Multi-DOF forceps without using any actuators. This forceps is lighter and more compact than the actuated forceps, and has higher manipulability than the conventional forceps. But the design of controller part is still-inadequate and difficult to control by one hand. In this paper, we proposed three types of controller part which is aimed to improve the manipulability. We assessed the interface by the experiment of screw setting up task and suture task.

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Microsurgery has attracted attention of people in recent years. However, as current surgery support system cannot present force sense to operators, it is difficult to use pratically. Using bilateral control, it will be possible to present kinesthetic sense to reduce the movement of hands and to perform safe microsurgery. In this paper, it aims at developing of the technology for the transmission of force sense in surgery support system. Bilateral control which conbines position control and impeadance control is proposed for tasks of moving object. Selection ratio of position control and impeadance control can be changed according to the interference of master-slave and environment, and the direction of force in consideration of operability and reproducibility.

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In the teleoperated minimally invasive surgery systems, measurement and display of sense of force to the operator is a problem. In this paper, a 7DOF forceps manipulator as slave has been developed using pneumatic actuators. We also developed a master manipulator using a delta mechanism and a gimbal mechanism with a force sensor and motors with reduction gears. In the developed master-slave system, we applied different impedance control to each manipulator. The force control type of impedance control is adopted without force sensor for the pneumatic slave manipulator. For the master manipulator admittance control is implemented. The experimental results indicated that the operator could feel the force at the slave side to a satisfactory extent.

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The research used to gives the sense of force feedback to person who operates when the endoscopic surgery is done. It is not necessary to manufacture the lengthy forceps, and it reports on the result of measuring force when person who operates open and shut the tip of forceps.

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Ionic polymer metal composites (IPMC) possess both structural and actuation properties, which makes them suitable for use in self-actuated compliant mechanisms. One limitation of IPMCs is that they can only bend with constant curvature along their length and this necessitates segmentation and individual control of each segment to realize compliant mechanisms for more complex motion. We have proposed a method of connecting adjacent segments of a multi-segment IPMC compliant mechanism so that they can bend with opposite curvature from the same electric source. Using this new ability, we have proposed and tested three different compliant mechanisms for wing-like motion, internally actuated bi-stable beam and a linear actuator, which were all controlled with a single input signal and would have otherwise required segmentation and individual control of each segment.

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We propose a new type of soft areal tactile sensor with pressure sensitive conductive rubber using inverse problem analysis. The significant feature of this type of sensor is that we don't need complex wiring in the center region, because we can estimate the conductivity change (i.e. pressure toward the sensor) in the center region based on electrical impedance tomography (EIT) technique that is a kind of inverse problem analysis. We will discuss the effectiveness of this type of sensor by verification of the prototype sensor system ability.

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In this paper, we describe about design evaluations of our robot coverd with soft foam plastic. In the first section of this paper, comparative discussion about possible materials of robot cover is described. In the second section, we explore a problem about management of movable area and a problem about thermal design. The soft cover should be designed with concern about the output of tactile sensor. The effect to sensor output is described also.

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The authors are developing an ultrasound-based integrated system for non-invasive diagnosis and treatment of kidney stones. The major goals of the system are to aid to detect kidney stones with ultrasound images and to eliminate them by cloud-cavitaion controlled lithotripsy using high intensity focused ultrasound (HIFU). The target kidney stone of lithotripsy moves during the treatment by breathing. Therefore, real-time motion tracking and servoing of the target kidney stone are necessary in order to improve the accuracy of the treatment and reduce treatment time. This paper describes the feasibility study of real-time 3D tracking and servoing with two ultrasound diagnostic probes and a 3D stage machine using ultrasonic radio frequency (RF) echo signal with regard to the therapeutic goal of the integrated system.

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The authors have developed an integrated system for the non-invasive ultrasound diagnosis and treatment to decrease the load of patients and medical doctors. In this paper, motion of a kidney and abdominal circumference information, which is acquired by a force sensor, are analyzsed at first. Secondly, the authors propose a feedforward controller to enhance the servoing performance of the system for model kidney stones by utilizing real-time information of abdominal circumference. Finally, experimental results show that the constructed system ia appropriate to presume the phase information of stone motion to generate the feedforward term of the controller.

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This paper reports a new microsurgery assist device for cooperative manipulation. The device, which integrates master-slave manipulations, is easy to setup because of the miniaturization, lightening, and omitting drive motor. Performance of device mechanism shows that 1.32mm error involved position accuracy of x-axis direction and 2.80mm flexure of x-axis direction. Analysis on the facilities of the four forceps attached to the device show that screw forceps and curved forceps is effective in grasp and transformation task. Required times for simple task such as grasp and needle insertion show that the device is able to reduce the time in the case of using curved forceps and cooperation by 2 peoples. Also, end-to-end and side-to-side anastomosis works show that the device is able to perform by cooperation working.

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In surgical robot systems, surgeons need to receive information regarding the contact forces on the tips of surgical instruments. For the detection of this contact force, one of the authors has proposed a new method, in which the instrument is supported by sensors positioned on the overcoat pipe. In this report, a device is designed to have actual surgical instrument drivers, and tested on its performances. As the results, the error magnitude of force measurement in various operational situations is about 0.1N or less. Another one device also is made to show grasp force of forceps to human fingers, and is cleared to have resolution about 1N.

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In surgical robot systems, surgeons can't recognize information regarding the contact force on the instruments. For the detection of contact, surgeons need some force information device. This paper proposes a force information device of grip type using vibration, and tests human's sensibility regarding the vibration. In the experiment, vibration is given intermittently or continuously. Also vibration amplitude is given in such ways as each motor changes in digital and whole motor does in analogue or motor in digital. This experiment gets six results for each subject.

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In laparoscopic surgical operation, the each ends of the forceps moves reversely to each other. The reverse motion might be a factor which makes surgeon miss-operate and causes the operation delay. This paper proposes a new device which cancels the reverse motion with pantograph mechanism on standing pose of surgeon. Authors evaluate the device by the required time for elemental surgical operations. A facility on manipulability of the instrument is searched on relation between hand motion and forceps motion in monitor. It is cleared that required time is reduced about 20% for knot working as an elemental surgical operation on the condition in which hand motion agrees with the forceps motion in monitor.

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Laparoscopic surgical operation has reverse motion in which forceps move reverse on Patient's inside to on the outside of the body. Reverse motion is troublesome for the surgeon, because that causes by the operation mistake and the operation delay. This paper proposes Machine Device on sitting condition with simple mechanism that cancels the reverse motion. Authors evaluate Machine Device by operation time for basic surgical operation. The results of experiment are described about the influence which the operation coordinate system and the view coordinate system give the surgeon. The best result is obtained when the operation coordinate system is corresponding to the view coordinate system.

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In a laparoscopic Radio Frequency Ablation, laparoscopic Ultrasound (LUS) probe is used for the needle insertion. In a former research, robot coordinate are decided from the stereo vision coordinate of laparoscope, and LUS picture is put on the coordinate. The insertion error of this method is about 3.0mm because of the error in fitting to a LUS picture. Author proposes a new method in which a LUS probe coordinate is expressed by the robot coordinate. Needle insertion method is described in the robot coordinate, and tested to confirm validity. As a result, needle insertion error of this method is about 0.4mm.

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The endoscopic surgical robot system in commerce can't feed back the contact force of the tip end of the surgical instrument. As the force measurement method, overcoat method has proposed using strain gauges. By the way, electric scalpel is used as one of essential tools. The electric scalpel uses high frequency electric current and gives electric noises to the strain gauge output. This paper proposes a force sensor which has to be constructed in a thin and narrow space for the overcoat sensing and to be free from the electric noises. In the force sensor, the fiber wiring traces are devised and light from the end of an optic fiber is injected to two ends of the other optic fibers which are attached on the force-deflection part. Experiments show that the sensor has sufficient possibility as the x and y direction force sensor.

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We developed two compact surgical support manipulators with a navigation system that uses an MRI, and a master console. One manipulator can hold a puncture needle in an MRI. The other manipulator can drive surgical tools in an MRI. Master console has two master devices and monitors for navigation, and is used to operate the manipulators. We installed the system in an MRI and could confirm movement of the system using navigation. We verified the feasibility of the prototype system by in-vivo experiment.

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In this study, we developed a neurosurgical robot tool as a part of a neurosurgical master slave system. As a prototype, we designed a manipulator, which has 3 degrees of freedom of bending, twisting, and grasping. The mechanical requirements were studied by the actual neurosurgery operation and human hand motions. The manipulator can rotate around a long axis beyond the bending axis using two pulleys placed perpendicularly, and can perform parallel grasping motion, which is similar to actual tweezers using a pantograph mechanism on its tip. A wire tension control mechanism is implemented to the drive unit of the neurosurgical robot tool.

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In this paper, a mechanism and its implementation of a minimally invasive surgical robot are presented. A parallel link mechanism was introduced for a remote center mechanism, which is a significant feature of a minimally invasive surgical robot. The robot was designed to be a motion base of various kinds of minimally invasive surgery.

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Until now, we have researched and developed the system of sampling the blood of fetus and the insertion system for solid organs like a liver, a brain ,and a breast which are both applied Curved Multi-Tube Device(CMTD). We can make the accuracy of insertion better by using CMTD. Before, we have reseached and developed the controls of CMTD mainly. In this research, we look at the bad side of the body motion attributable to breath and pain. Body motion leads to the bile duct move. In puncture of liver, bile duct is an insertion-target. It is a major contributor to unsuccessful management of puncture of liver. To deal with the problem, We added technology for target-tracking system with image processing using ultrasonnographic images and control technology to our needle-insertion system

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