In recent years, robots that can substitute for humans in dangerous activities, contributing to safety, cost reduction and efficiency have been developed. For example, a wall-climbing robot can clean and inspect high places, and approach disaster sites where a person cannot reach. In this study, the locomotion of snails is used as an effective wall-climbing mechanism. A snail moves by generating travelling waves with its muscle elasticity and propagating the wave in the direction of movement. Since this locomotion mechanism is in contact with a large area of ground, it is extremely stable. This is advantageous in climbing unstable walls. The proposed robot uses several Dual Hoekens linkages for locomotion and a fan to adhere to the wall by suction. We confirmed that this robot successfully climbs wall.

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We have developed an inspection equipment of a building with air injection. The apparatus can move over wherever we want to transfer it in a building with air injection and insertion. However, it could not fly with poise due to its flexible and simple structure. In this paper, first we confirmed basic features of the equipment to establish a system with air injection. Next we proposed how to wing the equipment steadily and avoid obstacles. Lastly we described future subject of the equipment.

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R-DMC is a one of mobile robots, and the robot is driven by 12 motors arranged on circumference. It is a most significant characteristics of structure of the robot that the robot has no tires and no reduction gears. The basic principle of moving mechanism of the robot is that the robot is driven by frictional force based upon sliding contact between end point of motor shaft and surface of ground. This robot is able to move easily towards 12 directions straightly and rotate around the center of robot. R-DMC has highly mobile performance, however it is not so easy to obtain suitable target values for each motors to satisfy desired motion of the robot. We had developed a autonomous R-DMC which equipped with control system and battery inside of the robot. In this study we had shown the experimental results of behavior of the robot, and considered relationship between motion of the robot and angular velocity of motors.

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This paper proposes a mechanism and control of a wheeled skid-steering mobile robot equipped with six feet for each wheel. Front and rear feet on one side are grouped into two. First one is odd numbered and second one is even numbered. Same things are said in other side. Therefore, the robot has 6 degrees of freedom (DOFs) totally. We consider robot controls for progressing and steering by rolling and walking since cooperative control of feet and wheel makes various movements on a terrain to cope with obstacles. Particularly, angular values of hip and knee joints are investigated in the two feet groups for stepping up or stepping over obstacles. These motions are demonstrated by the robot, PEOPLER-IV on a practical field for verifying that the proposed cooperative controls are useful.

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"RT-Mover P-type" is a personal mobility robot that can move on discontinuous rough terrain by using leg mechanism. But, it is difficult for this robot to continuous rough terrain by using conventional control method becouse of the wheel diameter is small compared to the weight. So, in this paper, as the first step, we propose the one of technique to improve on ability of wheel locomotion in rough terrain for "RT-Mover P-type". A mobile robot with bogie-type mechanism can move the rough terrain with small wheel diameter by using the proposed technique.

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We have proposed and reported a new wheel-feet hybrid mechanism, named as Enhanced Wheel System(EWS), for passing through a step or stairs. In artificial environment, wheels are not able to pass through a step or stairs, but they are superior to legs or crawler moving in flat fastly. So we proposed that machine moving by wheels gets over a step or stairs by EWS. To climb up stairs or a step by the EWS, several 'feet' combined on each wheel are kept horizontal by parallel link mechanisms. In this paper, we proposed a more compact stair climbing robot by improving 'feet' locomotion following the tracks of square using property of a Reuleaux triangle and thought what is need to use new EWS to climb up a step or stairs.

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Mobilities with wheels such as cars or bikes which have been used generally have a constrain of their motion and they cannot move toward wheel axis direction. On the other hand, omni-directional mobilities can move toward all direction and rotate on site. Our group has developed link-driven spherical wheel as omni-directional mechanism and omni-directional mobilities with it. Link-driven spherical wheel is superior to traditional spherical wheel mechanism at driving force but have some problem of omni-directional movement. This paper propose algorithm of omni-directional movement for link-driven spherical wheel and report the development of omni-directional mobilities with the wheels.

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This paper addresses mobile robots on a double spiral propulsion mechanism. Some groups of conservation of nature have surveyed wetlands as a part of preserving activity. But there is a demand of development of robots which support the investigation, because it is difficult to move in wetlands due to mud and dense weeds. The double spiral propulsion mechanism has been proposed for support in wetland investigation. A robot moves on the double spiral propulsion mechanism. This robot consists of movement mechanism on supporting legs and feet. This research considers a four-link movement mechanism of supporting legs, and the relationship among foot shapes, friction properties, and balance of a fixing frame.

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This paper describes the mechanism of the try cylindrical rover for exploration mission such a space exploration, search and rescue, and so on. The features of this mobile robot are the throwable and omnidirectional motion. The whole configuration of this robot is triangular cross-section and has the three cylindrical driving unit; omni-crawler at the each corner. The mechanism of this rover is shown and the basic functions are confirmed through the experiments with the actual prototype model.

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This paper presents a helical rotation mobile robot for in-pipe inspection driven by pneumatic actuators. A helical rotation is a motion in which a helical body revolves about its body axis. A helical rotation robot is less likely to injure the inside wall of the pipe and does not disturbs fluid flowing in the pipe. We developed two prototypes actuated by wire and SMA (shape memory alloy). In this paper, a new prototype consisting of three twisted silicone tubes is developed. It generates a helical rotation by expansion of the silicone tubes in turn. Its speed is increased up to 40mm/s and size is decreased. Moreover, it can move in a curved pipe.

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Mechanisms that overcome bumps are complicated and difficult to control. We propose a simple mechanism for getting over bumps. The authors developed a mechanism using six rotating legs and elastic body. By adjusting phase difference of six legs, the robot overcame the bumps smoothly. By using a rubber body, the robot didn't fall down when the robot lost the balance. Through experiments, verify validity of the mechanisms.

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When electrical stimulation constantly presents moving pattern to a finger, and shearing force is applied to the finger simultaneously, the participants feel as if their fingers slip though they do not actually move. We named this phenomenon "slipping illusion", and we proposed a pointing-stick-type GUI input device that applied this phenomenon, hoping that owing to the illusion, it can reproduce operation feeling of touchpad where the finger actually moves. In this paper, we investigated the occurrence condition of the slipping illusion focusing on the directional dependency of fingertip shear force and electrical stimulation flow.

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Walking support technologies are required in our aging society. An unconsidered reason for loss of motor functions in the aging is loss of sensory functions, which are detected not only by proprioceptive receptors but also by cutaneous receptors. In this study, we focus on the cutaneous receptors which are located at leg joints and perceive vibratory stimuli generated by walking steps. We expected that emphasizing the vibratory stimuli at the leg joints can support motor functions. In this paper, we measured vibration propagation on leg joints; an ankle and a knee, using small acoustic microphones when walking steps were performed under three different kinds of floor materials.

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Slip detecting tactile sensors are essential to achieving a human-like gripping motion with a robot hand. Up until now, we have proposed flexible, thin and lightweight slip sensor utilizing characteristics of pressure conductive rubber. This sensor can distinguish between condition of the object slip and the normal force change using a frequency component. In previous research, it was considered that the separation of these conditions was very difficult, but we managed to achieve it. We had suggested the separate algorithm by using Discrete Wavelet Transform signal processing. In this paper, we will discuss about the filtering method in the algorithm.

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Slip detecting tactile sensors are essential to achieving a human-like gripping motion with a robot hand. Up until now, we have proposed flexible, thin and lightweight slip sensor utilizing characteristics of pressure conductive rubber. When an object slides on the surface of our slip sensor, the complex output change occurs. By using this output change, this sensor can distinguish between the object slip and the normal force change. But, the mechanism of the complex voltage change is unclear. So, in this paper, we will observe the slip surface of an acrylic plate and the rubber with a high-speed camera. And, we report on the sensor output and the relation to the sensor output and the state of rubber.

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In this paper, we show investigate the effect of the visual cues to the tactual motion. We found following two facts. 1) Subjects tried to give a constant normal force independent on the texture provided the object is visible. 2) There are two ways of touch when it is invisible. One strategy is to give a stronger normal force to an object than that of the visible situation. The applied normal force is different depending on the texture. The other strategy is to give a constant force to an object. In this case, the applied normal force is weaker than that of the visible situation. Since there are two tendencies for touching an object under the invisible condition, we should take these features into consideration when we design the psychophysical experiment. Moreover, these insights can be used to optimize the surface condition of touch panel devices to improve the usability.

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A noncontact tactile display is developed in our laboratory, which provides tactile stimulation in midair by utilizing a nonlinear phenomenon of ultrasound; Acoustic radiation pressure. In the previous reports, a single or two arrays of ultrasound transducers are used and the resulting force acts only in one direction. That would limit the application area of the tactile display. In this paper, four arrays are arranged so that a user's hand is surrounded by them. The user can feel sufficient tactile stimulation in any direction owing to this array configuration.

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This paper proposes a remote compliance measurement method for one-to-many haptic communication like TV broadcasting. We cannot apply conventional master-slave haptic transmission systems to this kind of one-to-many communication, where many users share one object remotely at the same time via broadcast and/or internet. So we set our goal to realize a remote, non contact, and real time surface compliance distribution measurement. Our method utilizes an ultrasound phased array. It produces an ultrasound convergent beam and pushes a surface of an object, and then the surface displacement is obtained. In this paper, we describe our proposed method and report some fundamental experiments and their results.

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This paper proposes a haptic 3D modeling and displaying method of surface compliance distribution model of real objects measured by remote measurement system for one-to-many haptic communication. We cannot apply conventional master-slave haptic transmission systems to this kind of one-to-many communication, and we have to model the objects by measure the physical properties such as surface compliance distribution. The measured surface compliance distribution includes a lot of impulsive noises unlike artificially constructed model. These noises make haptic display less stable, and the effect can be harmful for the operator. We removed the impulsive noises by applying a median filter and evaluated the validity by PID controlled haptic display.

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With the advancement of information technology device, many tactile sensing device are developing. We aim at simple but sensitive tactile sensor and have proposed reflection-based tactile sensor. The reflection-based tactile sensor can employ LED (Light Emitting Diode) and PD (Photo Diode) as thin and fast sensing devices. However this sensing method does not have optical lens. This results in low density sensing because the sensor cannot employ imaging technology. The essence of the sensor is the distribution of brightness caused by diffused light. We have investigated the changes of three dimensional distribution according to simple deformation pattern through simulation. This time we consider the capability of this method from minute simulation, and design the reflection-based tactile sensor employing LED and PD.

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Vibratory stimuli lower than 50 [Hz] are perceived as roughness and/or softness sensation by human. However such low frequencies are difficult to achieve in small actuators loaded on mobile devices, and therefore, it is necessary to develop methods for enhancing human vibrotactile sensitivity. We focused on a phenomenon that human vibrotactile sensitivity is enhanced when a vibratory surface is touched with a stationary surface simultaneously. We call this phenomenon stationary-boundary-contact (SBC) enhancement. In this paper, we determined the performance of SBC-enhanced sensitivity by achieving the detection thresholds in several conditions.

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For reasons that have not yet been investigated, some textures appeal to human touch. We investigate the relationships between the physical and sensory factors, the predictability of textures, and their appeal to human touch. We use a set of 24 artificial clay stimuli in this study. We conduct sensory evaluation of textures, and the results are analyzed using factor analysis. Experimental results identify five sensory factors. We reveal that 70-80% of the textures' appeal to human touch can be described on the basis of the sensory and physical factors. We propose two models involving the predictability of textures. These models, as well as models based on the sensory and physical factors, explain the affinity to textures.

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We propose rotational slippage detection method using our proposed MEMS based tactile sensor. The sensor consists of small element which has three inclined micro cantilevers embedded in elastomer, and the element can detect both pressure and shear stresses. By using the sensor and k-NN machine learning algorithm, we could detect two pinching condition, rotational deformation (pre-stage of rotational slip) and point contact condition (rotational slippable condition).

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In this paper, two haptic devices with the different gear mechanisms are developed to investigate the influence of gear mechanism on the property of force display. Two servo loops were designed for impedance control and experiment were made to objectively evaluate the impedance control effect. Furthermore, subjective experiments of weight lifting were made for young subjects and analyses of weight cognition were made by the method of constant stimuli.

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In this paper, a new system for measurement of the hair condition is proposed. In this system, the voltages induced by the electrostatic charge between the proposed sensor and the hair are measured. The hair condition is estimated by using the measured waveform at the hair condition. In the experiment, three hair samples with different damage were prepared, and the induced voltages were respectively measured when the contact and release between the proposed sensor and the hair were repeatedly carried out. As a result, identification between the normal and damage hairs was possible by the proposed system.

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In this paper, a flexible contact sensor for three axis load measurement was developed. The sensor is consists of three components. One is a load measurement layer which composed of upper electrode, PC/20wt.%VGCF and lower electrode. The conductive materials (PC/20wt.%VGCF) to use for the load measurement layer have the property that resistance values decrease when load is burdened. Therefore, voltage changes between upper and lower electrodes can be measured. The other components are a skin layer and elastic body. The pattern of upper electrode was changed, the effect of the electrode pattern on sensitivity of sensor for normal load and shearing load was investigated.

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One of the issues for the soft robot hand is to measure the contact information that includes external force on the fingertip and corresponding finger posture. This paper aims to obtain the contact information without sensors on the fingertips, finger joints, and palm. Wefocus on the passivity of the McKibben pneumatic actuator in which the pressure is passively changed according to the external force. Experimental result with physical robot finger driven by the pneumatic actuator shows that the contact information can be estimated utilizing the approximation of the relationship between the pressure and the information. Considering that the pressure sensor can be attached outside the hand, the sensor-less robot hand that estimaes the contact information is realized.

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We have been developing an encounter type haptic device with an actively driven LCD pen tablet. An aim of the system is to develop the system that behaves as if the system itself is like the object when a user interacts with. When the user approaches to the system, pose of the LCD pen tablet and view point in VR display are controlled according to position of the user. And the system also can provide force feed back while the user is contacting to the LCD pen tablet.

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In this paper we discuss about the tactile information required for touchscreen interfaces, and propose a lateral-force-based 2.5-dimensional haptic display. The use of a lateral-force-based display enabled virtual bump sensations to be presented. Recently touchscreen interfaces have become popular worldwide. However, few touchscreens provide tactile feedback. Little hardware is commercialized for such kind of touchscreen. Some studies have focused on developing touchscreens that also provide tactile feedback. From our consideration, "press," "guide," and "sweep" movement are essential information for touchscreens. However, previous studies have some operational disadvantages for these information. We intend to cope with these disadvantages by introducing the new idea of lateral-force-based display. We developed an experimental prototype of lateral-force-based display, investigated 2.5-dimensional sensations, realized a part of these essential information, and confirmed the linearity between the presented force and the bump amplitude.

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Force sensing is necessary for robots which work with human or others. But, in general, the sensor resolution and rigidity are in the relation of contradiction. Therefore, coexisting of a highly accurate torque measurement and a good controllability is difficult. Torque encoder is a torque measuring system using digital linear encoder, and it has a high rigidity and high resolution. However, the crosstalk of the measurering becomes a trouble when torque encoder is installed in robot. Therefore, to reduce the crosstalk of Torque Encoder, We developed a compliant suspension mechanism. This paper proposes a dynamic assessment of suspension mechanism.

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Human's sensory inputs and motor outputs are closely bound together. This study is to make use of this relationship and to investigate how the presentation of the skin stretch to the finger pad affects the tracing movement. We develop a device that presents the shear deformation to the finger pad. Using this device, we conducted a preliminary experiment involving four participants and confirmed that presenting the shear deformation to the finger pad influence the tracing movement.

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In this paper, we developed a proximity sensor which detects an adjacent object. The sensor consists of reflection photosensor array and multiplexer scanning detection elements. We carried out experiments with varying the distance between the sensor and an object in order to examine the charastic of the sensor against distance change. We tried to estimate the shape of an object and indicated the possibility. We applied information processing to the voltage distribution for useful information such as image processing methods and statistical processing methods. We can estimate distance independent the reflective characteristic of an object between the sensor and the object by using coefficient of variation.

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This paper investigates efficiency of passive dynamic walking of a combined rimless wheel (CRW) that consists of two identical 8-legged rimless wheels. We derive the mathematical equations of the CRW and conduct numerical simulations to examine that a stable passive gait can be generated in the presence of the phase difference between fore and hind legs. We then numerically show that the phase difference improves the gait efficiency in terms of walking speed, and discuss the inherent speeding-up mechanism from the potential barrier point of view. Furthermore, the validity of the derived results is evaluated by using an experimental machine.

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A passive dynamic walking robot can walk down a gentle slope naturally without any actuator or controller, only by potential energy. Therefore, it is thought that the principle of walking exists in this phenomenon. By current researches, the passive dynamic walking has been confirmed for 2,4,and more than 6 legs. In the previous research, it was verified that a body of multi legged Passive Dynamic walker affected its gaits. In this research, the effect of body element of a quadrupedal Passive Dynamic Walking robot was analyzed in more detail on a simulator.

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In this paper, sustainable gait for a rimless wheel with joints is generated on a level ground, in which mechanical energy lost by heel strike is restored by kicking a ground. For the rimless wheel two kinds of period-doubling gait generation methods are proposed. First, period-two gait is generated by different energy restoration, in which each hip angle is the same value. Next, period-two gait is caused by different impact posture, that is, different hip angles when energy restoration by kicking the ground is constant. These methods separate effects of different energy restoration and asymmetricity for period-doubling gait. In the case of asymmetricity, it is shown that period-two gait is less efficient than period-one gait analytically.

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A Passive Dynamic Walking robot can walk down a gentle slope naturally without any actuator or controller, only using potential energy. This suggests that the principle of walking may exist in this phenomenon. Current researches have confirmed Passive Dynamic Walking (PDW) for biped and quadruped. However, it is also important and interesting to study PDW for more than six legs because it could be a significant approach for the resolution of the principle of walking. In this research, the super multilegged passive dynamic walking robot was analyzed by experiments with " Jenkka-III". And it was confirmed that the 20 legged robot could walk and its gait was changed depending on the degree of freedom of its bodies.

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This paper investigates active dynamic skipping of a planar telescopic-legged rimless wheel. Our model achieves stable limit-cycle skipping only by a simple extension control of the stance leg. We first generate a stable skipping gait by adjusting the desired settling time for the leg-extension control. We then analyze the gait efficiencies by comparing with those of walking and running gaits. Furthermore, we realize the transition from skipping to running gait by adding the ankle torque during skipping.

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The aim of this study is to realize the experiment of biped running, and we focus on the bouncing rod dynamics and its mechanism. The key point of bouncing rod dynamics is to transfer horizontal velocity into lifting momentum. In this study, we aim at a stable continuous running by the improvement of biped. And, we conducted experiment on running biped with knees.

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In our earlier work, we have demonstrated a passive running based on bouncing rod dynamics (hinged-movement) by experiment and simulation. And, we have stabilized passive running by particles in bar and feet. In this paper, we focus on the flow of particles in bar and a mechanism of feet. We realize further stabilization of passive running.

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Parametric excitation walking is one of methods to realize dynamic walking on a level ground. This method has been first applied to a biped robot with telescopic legs and later to a kneed biped robot. In parametric excitation walking, mechanical energy is increased by periodic up-and-down motion of the center of mass. While parametric excitation walking with telescopic legs has verified by a real robot, that with a kneed biped robot has not yet. The purpose of this paper is an experimental study of parametric excitation walking with a kneed biped robot. To do this, we develop a kneed biped robot having four parallel legs with semicircular feet and knee joints with motors. In the experiment, the robot can walk on a level ground more than 15 steps. We also measure the robot movements by a 3D motion capture and compare them with simulation results.

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As a walking which solves an energy efficiency problem of the biped robots, we are interested in a flat feet passive dynamic walking with ankle springs and ankle viscosities. The flat feet passive dynamic walking has an excellent performance and solves the problem of an arc-feet passive dynamic walking. For this reason, to obtain a level ground walking based on the flat feet passive dynamic walking, we propose a novel control method which combined a controlled symmetry and a push-off. Finally, we show that proposed walking has an excellent walking performance.

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In this paper we propose a compass type passive dynamic walking robot which has sensors to measure its dynamical parameters to analyze its walking gaits and behavior. A typical compass type walking robot has a difficulty to keep on walking because of its structure; the outer leg and the inner leg have same length, so the swing leg strikes its foot to the ground during its walking. To improve the problem we develop a new mechanism which expand and contract the second thigh part of the legs, and contribute to cut off the impact shock of ground contact. And then we investigate the behavior of Passive Dynamic Walking by the logged data of the robot.

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Many researchers have studied the material is done using robotic technology. The robot, which has been attracting attention as educational materials to many factors (mechanism design in machine shop, with electronic circuit design tools, programming for Control). In this study, for the dissemination of educational materials including engineering factors, and report on cases of technology in junior high school teaching.

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This paper investigates the self-stabilization principle underlying an underactuated bipedal gait generated by trajectory tracking control of the hip-joint angle. First, we introduce a planar underactuated compass-like biped robot with semicircular feet, and develop its dynamics and linearized system equation. We then design an output following control for the linearized robot's hip-joint angle. Second, we analytically derive the transition equation of state error for stance phase from the state space representation, and solve the stability and optimal conditions. Finally, the validity of the theoretical results is verified through numerical simulations.

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Blood sampling is frequently performed for clinical tests and in blood donations, and the skill of needle puncture is improved by two ways: a simulation practice by using a human body model and experiments of clinical trials. However the simulation practice does not consider difference of kinesthetic sense in venipuncture between the subjects. In addition, the trainee cannot practice positively in the clinical trials due to the subjects' burden. In this study, a needle puncture simulator reproducing kinesthetic senses of venipuncture using haptic technology has been prototyped. A haptic device of human interface was developed and the force sensor was calibrated. As the results, 2 dimensional motion of venipuncturing could be reproduced and it was suggested that noise suppression of the force sensor was required. And a tissue model with viscoelastic characteristic should be integrated into the control of the device.

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A small intestine has been called "the dark continent": and with the help of a conventional endoscope, previously unknown affliction of the small intestine can now be investigated. Recently, double-balloon endoscope and capsule endoscope have been applied to the inspection of the small intestine; however, some limitations of those techniques are evident. In this study, for decreasing the pain and distress in patients, we proposed a multistage type endoscopic robot that moves by peristaltic crawling. This robot is attached to the head of a conventional endoscope. When the endoscopic robot reaches the small intestine, it detaches itself from the endoscope and moves forward to treat the affliction. In this paper, we developed the propulsion mechanism. In addition, we performed experiments by using an acrylic pipe and an elastic tube both of which have diameters equal to the average diameter of the small intestine. Satisfactory performances were obtained from the experiments.

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The needs of force measurement are getting stronger in advanced medical technologies for realizing advanced treatments and precise assessments. In this paper, a tube shape force sensor using optical fiber is presented. The sensor realizes a precise 3-DOF force measurement using multiple optical fibers. A preliminary test revealed that the sensor has a linear characteristic according to the load. In addition, we conducted frequency analysis of the sensor output which is observed in temperature changing environment. As a result, the sensor also realizes a thermal compensation applying High-pass filter based on frequency analysis.

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We propose a robustness enhancement methodology of motion compensation for non-invasive HIFU theragnostic system. The methodology is a combination of US-based visual tracking and skin-motion tracking by optical sensor. In this paper, we report the kidney motion model, which estimates kidney position from the measured skin position moving during respirations. Before the treatment, skin position and kidney position are measured simultaneously. To measure skin position, external markers are attached on patient's abdomen, and tracked by camera. To measure motion of kidney, we apply template-matching scheme for the stream of US images. Therefore, the correlation between measured skin position and kidney position is computed. During treatment, kidney position is estimated from the measured skin position using the correlation.

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In the present paper, we introduce the hybrid tracking method using preoperative and intraoperative patient data for non-invasive robotic HIFU system. For the initial target recognition for the unclear target area, we register the preoperative 3-D model to the 2.5-D biplane US images. Moreover, we create an intraoperative tracking landmark in the target area by HIFU thermal ablation. During the target motion, we detect the US speckle image change by the HIFU treatment. Specifically, the CONDENSATION algorithm was applied to a robust and real-time speckle pattern tracking in the sequence of US images. Moreover, biplane US imaging was used to locate the three-dimensional position of the US speckle change, and a three-actuator system drives the end-effector to compensate the motion. Experiment for the motion compensation was conducted with robotic US-guided HIFU system. In the experiment, kidney motion of the phantom model was simulated by the captured human kidney motion data. As a result, the accuracy of the motion compensation was approximately 1.5 mm.

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We propose a non-invasive ultrasound theragnostic system that tracks movement in an affected area (kidney stones, in this study) by irradiating it with high-intensity focused ultrasound (HIFU). In this paper, the concept behind a novel medical support system that integrates therapy and diagnostics (theragnostics), is illustrated. The required functions for the proposed system are discussed and an overview of the constructed system configuration is illustrated. Problems of stone motion extracting, tracking, monitoring by ultrasonography are described. To overcome with this problem, we should take 2 approaches. The first approach is to minimize the servoing error to enhance both the efficiency of the therapy and the safety of the patient. The second approach is to reduce the effect of the servoing error. Concerning the first approach, we propose 2 solutions. One is robust detection of the stone position by shape information. Another is the controller that compensates for periodic motion of the affected area. Concerning the second approach, we propse a solution to control HIFU irradiation power in accordance with the servoing error, mainly to enhance the safety of the patient.

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