We are developing a human-riding wheeled inverted pendulum for use as a personal vehicle. To be practically usable, the vehicle requires a function that enables the rider to get on and off both safely and smoothly while on a slope of unknown angle. Concretely, for the convenience of the rider, the vehicle needs to be stabilized on an unknown slope without the rider aboard, both before the rider gets on it and after he/she gets off it. Moreover, the vehicle should be stabilized safely relative to the rider's handling force at a grip of the vehicle while getting on and off. We thus developed a method of estimating the handling force and the slope angle separately. In this paper, we report the method to estimate the handling force and the slope angle using a disturbance observer. We verified the validity of our proposed estimation method by computer simulations and experiments using a prototype of a human-riding wheeled inverted pendulum on an unknown slope.

A robotic transportation system for shopping support services has been developed. The system is required to act according to the customer's request and position to provide services. In collaboration with mobile robots, the system provides shopping support services.

We have developed a casting manipulator that includes a flexible light string in the link mechanism to enlarge the workspace of the manipulator. In the casting manipulation, an end-effector is launched to its target by releasing the string connected to it, and its trajectory is controlled by the tension of the string. In this paper, we present the midair control of the end-effector. As a simple way, we propose the braking technique to apply impulsive force to the end-effector by braking the movement of the string. Examining dynamic characteristics of the string when an impulsive force applies to it, we show that the midair motion of the end-effector can be controlled by the braking technique. Then, we apply the braking technique to the multiple braking control of the trajectory. We confirm the effectiveness of the proposed method through simulations and experiments using casting manipulator hardware.

In this paper, we propose an environment-adaptive antipersonnel mine detection system called Advanced Mine Sweeper. Advanced Mine Sweeper is developed based on sensing technologies, access-control technologies and system integration technologies for safe and effective demining procedure after the Level II survey. Advanced Mine Sweeper consists of a sensing vehicle/unit, an access vehicle, and an assist vehicle. The sensing vehicle/unit is composed of an integrated sensor and a small-reaction sensor head manipulator. The access vehicle is parked facing a mine field in order to control the sensing unit position in a global area using its boom. The assist vehicle is parked keeping some distance from a mine field. It controls the sensing vehicle/unit and access vehicle and then displays the processed sensing information for landmine detection, receiving sensing information and sensing position. By using this system, experiments in the field buried dummy landmines were carried out for the utility and performance evaluation

This paper reports on the development of the "TAO Aicle", an intelligent wheelchair with autonomous traveling capability. The wheelchair can accurately determine its position and direction using internal sensors and external assistance from the surrounding environment, including the Global Positioning System (GPS) and Radio Frequency Identification (RFID). It can also detect obstacles it encounters on the road using a laser range sensor. To confirm the effectiveness of our research results, for six months at the Aichi Expo 2005 we demonstrated the wheelchair system by offering trial rides to visitors. This paper describes the total system of "TAO Aicle", the positioning method using GPS and RFID, and the autonomous traveling control based on accurate estimations of position and direction using Kalman filtering. Our experimental results at the Aichi Expo demonstrated that accurate trajectory following performance can be achieved using assistance from the infrastructure (GPS, RFID) and that "TAO Aicle" could perform safe autonomous traveling without severe accidents.

In this paper, we present a method to control Kendama by casting manipulation. Casting manipulation is a technique to control an end-effector in the air by throwing the end-effector and controlling its ballistic flight using impulsive forces transmitted through a light string connected to the end-effector itself. First, we examine dynamic characteristics of a flexible string against impulsive force. We propose a method of identifying the viscoelastic model parameters of the string through free-fall experiments. Then the technique of braking the string is applied to the trajectory control with consideration of the time delay and slip of the brake. We conduct the rebound experiments by the braking technique to confirm its effectiveness. We analyse the work space where the suitable motion of end-effector for Kendama game is generated by multiple braking. Kendama game, motion of making the perforated ball impaled on the stick, is demonstrated by casting manipulator hardware.

This paper reports on the continued development of a new concept for a personal vehicle called the 'personal riding-type wheeled mobile platform (PMP)' that consists of two wheels and a standing base for a human rider. The two wheels are driven independently, and forward and backward movement and steering are achieved by simply changing the relative position of the rider's center of gravity (COG) on the base. The vehicle has two distinct advantages: a reduction in total weight through its simple structure and a space-saving design that does not use a steering unit. We have already proposed the first prototype (PMP-1) and its posture stabilizing and running control methods, and we have achieved proper forward and backward movement according to the rider's intentions. This paper describes our proposed structure for detecting the rider's COG on the base and the steering control method in order to achieve steering control by changing the position of the rider's COG and the second prototype (PMP-2) whose weight is smaller than 12kg. We also investigated the steering control method to improve maneuverability in various estimated standing poses. Our experimental results demonstrate that natural steering control can be achieved using the rider's COG based on the rider's intentions.

A previously developed passively operating transmission capable of switching its reduction ratio in response to load torque was further developed into a non-contact load-responsive transmission. The reduction ratio is switched by a non-contact magnetic clutch that responds to the load torque using a passive magnetic mechanism without any accessory actuators, sensors, electronics or power supplies. The absence of mechanical friction at the non-contact magnetic clutch resolves the problems concerning the wear and maintenance, shock while switching the clutch is greatly reduced and the actuator is protected from overloads by slippage at the magnetic clutch. This non-contact load-responsive transmission reduces the power, size and weight of the mechanical system and improves its safety and agility since a variant load can be actuated efficiently using a minimal actuator. This paper describes the structure and the operation of the non-contact load-responsive transmission and reports on the characteristics of an experimentally evaluated prototype transmission.

We propose a new concept in personal vehicles called the 'Personal riding-type wheeled Mobile Platform (PMP)' consisting of two wheels and a standing base for a human. The two wheels are driven independently, and traveling and steering is achieved by simply changing the relative position of the rider's center of gravity (COG) on the base. The vehicle has two merits: reducing the total weight of the simple structure and saving space by not using a steering unit. In this paper, the mechanism of the first prototype, PMP-1, is introduced and its posture stabilizing and running control methods are proposed. The effectiveness of the posture stabilization control methods is demonstrated in computer simulations and human riding experiments. In the running control method, maneuverability by movement of the rider's COG is also investigated experimentally. The results demonstrate that the posture of the rider can be maintained and the velocity of forward and backward traveling can be controlled according to the rider's intentions.

A passively operating load-responsive transmission capable of switching the reduction ration in response to load-torque was developed. When the load torque is low, the transmission operates with a low reduction ratio that enables the actuator to rotate a high-speed and low-torque load efficiently. When the load torque increases, the transmission switches to a high reduction ratio to rotate a low-speed and high-torque load. The reduction ratio is switched by a pair of clutches connected and disconnected separately. These clutches are passively operated by the magnetic mechanism that exerts thrust in alternative direction responding to the load torque without any accessory actuators, sensors, electronics or power supplies. The load-responsive transmission can reduce power, size and weight of the mechanical system and improve its safety since a variant load can be actuated efficiently by a minimal actuator. In this paper, the advantages and requirements of the load-responsive transmission are first outlined followed by the structure and the operation of the developed transmission. Further, the characteristics of a prototype transmission are experimentally evaluated.

This paper describes the eye movement tracking type image display system that can display a wide view angle image with high resolution using human eye characteristics, although conventional displays are used. The principle is that a small high-resolution image is presented at the viewpoint superimposed over a wide view angle image of low resolution by using two displays. Human can see an object as a high-resolution image only near the viewpoint. Therefore, the operator can feel that the displayed image has wide view angle with high resolution. In this paper, the image capturing and the display system are discussed. Some evaluation experiments for the high-resolution image presentation, which is followed by eye movement, are introduced using the prototype system.

Presents the utilization of inertial effect in damping-based posture control of a mobile manipulator. As a measure for redundancy resolution of a mobile manipulator, an effective inertia at the end effector in the operational space is proposed and investigated. By changing the effective inertia property via null-motion, we can get the reduced inertial property of the mobile manipulator. The reduced effective inertia has a significant effect on reducing the impulse force in collision with the environment. To find a posture satisfying both the reduced inertia and joint limit constraints, we propose a combined potential function method which can deal with multiple constraints. The proposed reduced inertia property algorithm is integrated into a damping controller to reduce the impulse force at collision and to regulate the contact force in mobile manipulation.

A microfactory is a new concept for an extremely miniaturized manufacturing facility that enables dramatic space and energy conservation. As a material transfer and assembly component of a prototype microfactory, a micro transfer arm that provides 4-DOF and a maximum length of approximately 100 mm has been developed. To achieve a compact-lightweight structure, large workspace and high positioning accuracy, the arm is configured as a combination of a SCARA-type manipulator and a parallel mechanism. To enable the arm to perform fine assembly tasks, a 3-axis device with an integrated passive compliance device and force sensor was developed. In this paper the mechanical design of the arm structure and the fabrication process of the device are described, followed by an experimental evaluation for the arm and device.

Deals with the reduced inertial effect in damping-based posture control of a mobile manipulator. As a measure for redundancy resolution of a mobile manipulator, an effective inertia at the end effector in the operational space is proposed and investigated. The reduced effective inertia has a significant effect on reducing the impulse force in collision with environment. To find a posture satisfying both the reduced inertia and joint limit constraints, we propose a combined potential function method that can deal with multiple constraints. The proposed reduced inertia property algorithm is integrated into a damping controller to reduce the impulse force at collision and to regulate the contact force in mobile manipulation. The experimental results show that the reduced inertial effect of the mobile manipulator alleviates the impact force at collision.

We have been developing a casting manipulator which includes flexible string in the link mechanism to enlarge the work space of the manipulator. In the casting manipulation, a gripper is thrown to its target by releasing the string at a suitable time after generating enough motion of the gripper by swinging. In the paper we deal with the midair motion control of the gripper after throwing it for catching a target. First, we point out the necessity of controlling the gripper in midair after throwing it. Then we propose the utilization of an impulsive force applied to the gripper in the air by restricting and releasing the motion of the string. Investigating the impulsive force generation through experiments, we proposed the plural braking control of the gripper and confirmed the effectiveness of the method by simulation results.

Various coordinated control schemes are explored in the multi-operator-multi-robot (MOMR) tele-collaborative system through a network with time delay. Multi-robot cooperation has rapidly emerged in many possible applications such as the plant maintenance, construction, and surgery, because it would have a significant advantage over a single robot in such cases. Thus, time-delayed control of a multi-robot system is expected to play an important role in remote operations, too. However, the effect of time-delay would pose a more difficult problem to the MOMR teleoperation systems and seriously affect their performance. In this work, first, we have built an experimental system to investigate the remote cooperation in MOMR teleoperation. Then, different coordinated control methods are proposed to cope with the collision, arising from the time delay over the network. To verify the validity of the proposed schemes, we have carried out various experiments on a planar block arrangement by two slave arms employing graphic simulators and a LAN subject to a significant communication delay.

Since a biped robot tends to tip over easily, stable and reliable biped walking is a very important achievement. In this paper, we propose a balance control method based on an off-line planned walking pattern with real-time modification. First, a method of generating a highly stable, smooth walking pattern is presented. Then, a method of real-time modification consisting of body posture control, actual zero moment point control and landing time control based sensor information is proposed. By combining the proposed off-line walking pattern with real-time modification, the biped robot can walk smoothly and adapt to unknown environments. The effectiveness of the proposed method is confirmed by dynamic simulator such as walking on unexpected irregular rough terrain, soft ground and in environments in the presence of disturbances.

We have been developing a casting manipulator which includes a flexible arm made out of soft material like a string in the link mechanism to enlarge the work space of the manipulator. In casting manipulation, a gripper is thrown to its target by releasing the string at a suitable time after generating enough motion of the gripper by swinging. In this paper we deal with the catching motion control of the gripper. We consider the necessity of the midair control of the gripper for catching a target. In order to enlarge the reachable area of the gripper, we propose the method of controlling the movement of the string by the brake mechanism. We confirmed the effectiveness of the proposed multiple braking control by simulation results and experimental results.

The Mechanical Engineering Laboratory (MEL) is developing technologies for multi-robot collaboration in remote environments with the Toshiba Mechanical Systems Laboratory (TMSL). Human operators' delayed visual perception due to the communication delay over the network seriously affects the collaboration performance in the multi-operator-multi-robot tele-manipulation. We have built an experimental tele-manipulation test bed connecting the MEL and the TMSL to study the time-delayed remote tele-collaboration between two places. In the test bed, one operator controls her master robot nearby two slave robots in the work site and another from a distance. A local online graphics simulator without time delay is developed to cope with the communication delay and several multi-robot coordinated control strategies are devised to avoid the collision. To verify the validity of this simulator assisted approach, we demonstrated a maintenance work on a plant mock-up in the TMSL by two different slave robots and two distant operators in the MEL and TMSL respectively through an ISDN.

We develop a casting manipulator which includes a flexible string in the link mechanism to enlarge the work space of the manipulator. During casting manipulation the gripper is thrown to the target by releasing the string at a suitable time after generating enough motion by swinging. In this paper we deal with the posture control of the gripper after the throwing motion. First, we point out the problems of planning for throwing the gripper while considering its posture when catching. Then we propose a method of applying an impulsive force to the gripper in the air through the string by restricting the motion of the string. Investigating the characteristics of the string through experiments, we confirm the effectiveness of the impulsive force. This method was evaluated by comparing the results of numerical simulations with those of our experiments using the experimental casting manipulator hardware.

Biped robots have better mobility than conventional wheeled robots, but they tip over easily. In order to walk stably in various environments such as rough terrain, up and down slopes, or regions containing obstacles, it is desirable to adapt to such ground conditions with a suitable foot motion, and maintain the stability of the robot by a smooth hip motion. We propose a method to plan a walking pattern consisting of a foot trajectory and a hip trajectory. First, we formulate the constraints of a foot trajectory, and generate the foot trajectory by 3rd order spline interpolation. By setting the values of constraint parameters, it is easy to produce different types of foot motion. Then, we formulate a hip trajectory using a 3rd order periodic spline function, and derive the hip trajectory with high stability. Finally, the effectiveness of the proposed method is illustrated by simulation examples.

Proposes task-based data exchange for teleoperation systems through a communication network as an efficient method of transmitting data between an operation device and a remote robot. On the task-based data exchange, the more important information according to the contents and conditions of the task which the robot performs is given transmission priority, for example, by altering the contents of the transmitted data. We have built an experimental system in which the master arm in Tsukuba and the slave arm in Kawasaki, separated by, about 100 km, are connected through N-ISDN and the standard techniques are utilized, such as TCP/IP, socket, JPEG, etc. A series of experimental tasks has been effectively carried out by the task-based data exchange, that is, crank operation which consists of grasping and revolution. The communication network with capacity limitations was used effectively, and the high maneuverability in real-time with bilateral servo control has been realized. The effectiveness of the task-based data exchange has been confirmed.

We have been developing a casting manipulator which includes a flexible string in the link mechanism to enlarge the work space of the manipulator. During casting manipulation, a gripper is thrown to its target by releasing the string at a suitable time after generating enough motion by swinging. In this paper we deal with the midair control of the gripper after throwing it. First, we consider the factors which disturb the trajectory of the gripper, and point out the necessity of modifying the trajectory after throwing the gripper. Then we propose the utilization of an impulsive force applied to the gripper in the air through the string by restricting the motion of the string. Investigating the impulsive force generation through experiments, we confirmed the effectiveness of the method which was evaluated by comparing the results of numerical simulations with those of our experiments using the experimental casting manipulator hardware.

Since most conventional robots cannot easily be adapted to environments designed for humans, a human-size biped robot is expected to be able to play an important role in assisting human activities. The selection of suitable joint actuators is an important point when developing a human-size biped robot. In order to select suitable actuators and effectively utilize the selected actuators, it is necessary to clarify the relationship between walking patterns and the specifications of each joint actuator, and this is the issue tackled in the paper. First, a method of generating a high stability, smooth walking pattern is presented, and it is shown how various walking patterns can be produced by setting a series of defined walking parameters. Then, the dynamics of the robot, including the reaction force between the feet and the ground, are formulated. Finally, by simulation studies, the correlation found between actuator specifications and walking patterns is described, and the effectiveness of the proposed method is suggested.

In this paper, remote robot collaboration using a network with communication time delay is discussed in multi-operator-multi-robot (MOMR) teleoperation. Recently, collaboration tasks have rapidly emerged in many possible applications such as plant maintenance, construction, and surgery, because multi-robot collaboration would have a significant advantage over a single robot in such cases. Problems and several noticeable results have been reported in a single-operator-single-robot (SOSR) teleoperation system. However, the effect of time-delay would pose a more difficult problem to the MOMR teleoperation systems and seriously affect their performance. In this work, first, some of the constraints on performance in MOMR teleoperation applications are examined. Then, the time-delay effects on tele-collaboration are investigated through several experimental studies. Finally, a method to cope with the time-delay in MOMR teleoperation systems is proposed exploiting the virtual thickness modification scheme.

We have been developing a casting manipulator which includes a flexible string in the link mechanism in order to enlarge the work space of the manipulator. Like the casting motion of fly fishing, the necessary motion of the gripper, which is attached at the end of the string, is generated by swinging a rigid link The gripper is thrown to the target by releasing the string at the suitable time. In this paper we deal with the basic swing motion control of the casting manipulator. We describe a method of oscillating the casting manipulator by considering it as a two-degrees-of-freedom nonholonomic system By planning a time-periodic reference for the second joint while controlling the first joint, the desired swing motion of the system can be generated. The method was evaluated by comparing the results of numerical simulation and those of experiments using the casting manipulator hardware.

We have been developing a casting manipulator which includes a flexible string in the link mechanism in order to enlarge the work space of the manipulator. Like the casting motion of fly fishing, the necessary motion of the gripper, which is attached at the end of the string, is generated by swinging a rigid link. The gripper is thrown to the target by releasing the string at the suitable time. We deal with the swing motion and throwing motion of the casting manipulation. First, we describe a method of oscillating the casting manipulator by considering it as a two degrees of freedom nonholonomic system. The method of the swing motion generation is investigated through experiments. Next we propose a method of planning of throwing the gripper considering the time delay of releasing the gripper and frictional force which disturbs the flying motion of the gripper. The evaluation by comparing the results of numerical simulation with those of experiments using the casting manipulator hardware has shown the effectiveness of the proposed methods.

A bilateral control system for scaled teleoperation provides the human operator with a feel of the task as well as the teleoperation between same-scale worlds. A maneuverability of the teleoperation system depends on the bilateral control scheme. This paper, first, reviews several bilateral control schemes for the scaled teleoperation, which have already been developed, and points out its dexterity issue of teleoperation. From these reviews with considering physical meaning of bilateral controllers, secondly, this paper proposes a novel bilateral control scheme that realizes macro-micro teleoperation with natural force feedback sensation. An idea of control scheme is come by taking notice that the system parameter values of master site and those of slave site are different. This control scheme is based on operational force feedforward type bilateral control with scaling gains. We also study the operational feeling of the proposed control scheme and compare with several bilateral control schemes in theory. Finally, we present experimental results that verify the validity of the proposed control scheme.

In the teleoperation between different-scale worlds, it is important to consider the scaling effect problem. An impedance shaping bilateral teleoperation that considers this problem is needed to provide the human operator with natural sensation while tele-manipulating objects in the micro world whose main physical characteristics are different from those in the macro world. In this paper, we propose a bilateral control scheme which provides the operator with an impedance shaped out of the real one. This control scheme is based on force feedback bilateral control with scaling transfer function gains. By choosing not only the geometrical scaling gains but also the dynamic scaling ones as the scaling transfer function gains, the impedance that is presented to the operator can be shaped out of the real one. Finally, we present experimental results that verify the validity of the proposed control scheme.

The kinematics, statics and stiffness effect of a 3D grasp by a multifingered hand is investigated considering the rolling contact at the fingertip. By representing the local shape of the fingertip and the object by a quadratic surface and by linearization of the fundamental formulae, the kinematic-static relation for the motion-force of the fingertip, contact location and the object is derived. Additionally, the stiffness effect for object motion that affects the stability of the grasp is analyzed and evaluated for the grasp by a three-fingered hand.

We propose a new type of manipulator, a casting manipulator, which includes flexible parts, such as a string, in the link mechanism. A gripper is attached at the end of the string. In order to let the gripper reach a target, the rigid link is swung until the necessary motion of the gripper is generated. The gripper is then thrown to the target by releasing the string at the suitable time. In this paper we describe the manipulation of a casting manipulator. We present a method of oscillating a casting manipulator by considering it as a two-degrees-of-freedom nonholonomic system. First, we propose a method to swing the manipulator for casting motion, and then discuss the selection of swing motion and decision of the timing for releasing the string.

Dynamic grasping force control for a multifingered hand is proposed and investigated. The grasping force of the finger is dynamically adjusted according to the tactile feedback so that each fingertip force always stays inside the friction cone detected by the tactile sensor and the fingertips maintain firm contact without any undesired slip no detaching from the surface of the object while grasping it. The proposed method can be applied for real-time control of the hand since it requires few numerical calculations. The validity of the proposed method is experimentally confirmed using a two-fingered hand with finger-shaped tactile sensors.

Identifying and implementing high fidelity scaling laws in scaled teleoperated systems is still a challenge. We propose the use of additional information (e.g., auditory and tactile) to complement and supplement the normal visual and force channels and thereby provide sensory enhancement when performing delicate tasks. We support our proposal by presenting experimental results from tests performed by humans on a hybrid hardware-software telemanipulation system. Our results show that integrating auditory and tactile feedback improved the performance of the operator.

A new motion control system using tactile feedback is investigated for the manipulation of an object by a multifingered hand where the fingertips and the object make rolling contact. The proposed control system is capable of determining the motion of fingers so that the hand manipulates the object along the desired trajectory according to the tactile feedback at the fingertip. The advantage of the algorithm developed here is that geometrical information about the object to be manipulated is not necessary and therefore the algorithm can be applied to the manipulation of an unknown object. First, a mathematical model of the kinematics of the manipulation with rolling contact at the fingertip is formulated. Next, a trajectory planning algorithm for the fingers is derived. Finally, the previously developed finger-shaped tactile sensor using an optical waveguide is installed on the two-fingered hand, and the superiority of the proposed algorithm is demonstrated through computer simulations and experiments.

Requirements for fast and accurate motion in industrial robot manipulators demand more advanced control techniques. Past techniques, such as the resolved acceleration method and nonlinear feedback control, etc. require detailed information on mechanical parameters. In these methods, the modelling errors adversely effect manipulator motion. To overcome this problem, this paper proposes a method for constructing nominal dynamic modelling for a robotic arm in the operational space. When the proposed method realizes a disturbance observer in the operational space, individual coordinate motions can be decoupled and independently controlled. Further, individual motion in the operational space coordinate is driven as if only nominally fixed mechanical dynamics in the operational space existed. As a result, the method enables one to construct the control law without any calibration for the mechanical parameters. Finally, the authors present experimental results from an implementation of the proposed method.>

One of the essential parts of dextrous manipulation with fingers is the use of sliding motion. Sliding manipulation techniques can fulfil tasks, such as a change of contact point between fingers and objects, a change in the location of objects without losing contact under unknown object-fingertip surface conditions or the determination of an optimal grasp force in order to avoid losing grasped objects. These techniques require a knowledge of the friction coefficients between the finger and the object. A method of slip detection and static friction coefficient determination, requiring no additional sensors than the existing joint position and force sensors of a two fingered robot hand system, is proposed. This method is applicable to general use in multi-fingered robot hand systems. The authors describe the principle of slip detection using the stick-slip effect and the required control algorithm for grasp forces. The performance of the described method is demonstrated on a pick-up task application. Considerations due to experimental results are discussed.>

Recent requirements for fast and accurate motion in industrial robot manipulators demand more advanced control techniques. For these requirements, many manipulator control methods have been developed. One of them is a manipulator control based on the disturbance observer. The disturbance observer estimates the disturbance torque (force) using a nominal model and compensates for the parameter variations between the real manipulator and the nominal model. Because of the high performance and simple algorithm, its usefulness for real time control the disturbance observer has recently been employed for manipulator control. This paper analyzes a manipulator control based on the disturbance observer. From this analysis, we also propose a design method of the manipulator control based on the disturbance observer. Finally, we present experimental results from an implementation of the proposed method.>

Recognition of the actual position is very important for a mobile robot to move around in its environment. The most common method of position estimation is dead reckoning usually achieved by integrating wheel rotation along the path. This method, however, has a serious problem that the estimation errors are accumulated. In this paper we propose using an optical fiber gyroscope (OFG) combined with the information provided by the wheel encoders to improve the accuracy of position estimation. The formulation using a Kalman filter to combine the information of the encoders with that of the OFG is described. The simulation results and the experimental results show the effectiveness of the proposed method.>

This paper presents an algorithm for estimating the interaction forces between model objects contacting at multiple points. The authors' previous work addressed the interaction forces that arise between two convex polyhedra, and the development of an efficient algorithm for detecting the interaction and for estimating the interaction forces. To deal with the general case of multiple contacts, the authors consider the non-convex objects as a set of convex polyhedral parts. The problem of calculating the interaction forces with multiple contacts can be divided into multiple problems involving the calculation of the interaction forces arising between two convex objects making a single contact. By implementing this algorithm on a parallel processing system, the authors constructed a real-time operating simulator. Preliminary experiments, involving the placement of a cube in a corner, were performed to evaluate the effectiveness of the system.>

A finger-shaped tactile sensor previously reported in a scaled-up version was miniaturized and its signal processing speed improved. The miniaturized tactile sensor consists of a hemispherical optical waveguide with an elastic cover, a fiber-optics plate (FOP), a position-sensitive detector (PSD), and infrared light-emitting diodes (LEDs) for the light source. When an object comes in contact with the sensor, the elastic cover is depressed and light from the LEDs, which normally maintains total internal reflection within the waveguide, is scattered at the contact location of the waveguide and the cover. The scattered light is transmitted to the PSD through the FOP. The contact location and the normal to the surface of the object are determined from the output of the PSD. The sensor's fundamental characteristics were evaluated through experiments using the miniaturized version. The sensor was installed at the tip of a robotic finger to create an active touch system. By combining tactile sensing and motion control of the finger, the profile of an unseen object was successfully delineated.>

Recognition of its current location is im- portant for a mobile robot to follow a planned path. Landmarks, which are assumed in the environment around the robot, are used to support this recognition. In this paper we propose a method for the robot to select the most suitable landmark among the measur- able landmarks from its current position by evaluating the error covariance update of the position estimation. We use the extended Kalman filter to update the po- sition estimation. We show the update behaviors of two types of landmarks : line type and point type. For the criteria of the evaluation we use the widths of the error ellipses, perpendicular to the direction of the course. Through the simulation of navigating a robot along the center lines of corridors the effectiveness of the proposed method is confirmed. ing landmarks the position estimation is updated in the same way. The behaviors of using two types of landmarks, a line type landmark and a point type one, are examined. The position estimation using a particular landmark is ex- pressed by an error ellipse which is derived from the error covariance update and which shows the directional error distribution of the estimated position error. Though it is favorable if the radius of the error ellipse is small in all di- rections, we think the width of the ellipse along the course is important and propose to use it as the criterion for the selection of the landmark. By the simulation of navigating a robot along the center lines of corridors the effectiveness of navigation based on the proposed landmark selection method is shown.