When a disaster occurs, high output power should be available for rescue operation even if the electric supply is insufficient at site. This video presents a novel multi-fingered robot hand for extreme environments without a sufficient electric supply. The robot hand has four fingers with 16 joints and 12 degrees of freedom. The finger has a retention mechanism using no electrical power supply and a fingertip force of 150 [N]. Holding without power supply shows that our robot hand can lift a heavy barbell and keep its posture without using electrical power. The high fingertip force shows that steel cans can be crushed by the robot hand. In addition, dexterous motion of our robot hand shows that each finger allows flexion/extension and adduction/abduction. High-power manipulation shows that the robot hand can grasp and manipulate a hammer drill for making a hole in a concrete plate. The robot hand has a high potential for performing various tasks by obtaining high power output and electrical power saving.

When we touch a human body, the flesh yields to our touch and we feel a sensation of softness. In virtual training systems for medical procedures such as palpation, the display of softness at the fingertips is essential. This paper proposes a softness-display device using a flexible sheet, and we present the concept of softness display at multiple fingers by combining the developed softness-display device and a multi-fingered haptic interface robot consisting of a five-fingered hand and an arm. Further, we carried out several experiments, the results of which show the validity of the proposed system and its great potential.

This paper presents a novel learning system for myoelectric prosthetic hand control by forearm amputees using estimations of continuous joint angles. Wavelengths calculated using surface electromyogram (sEMG) signals of forearm amputees are input into a neural network (NN); past inputs are also used to take finger dynamics into consideration when estimating the metacarpophalangeal joint angles of each finger and wrist joint angle of pronation/supination and palmar flexion/dorsiflexion. The learning system has a three-step learning dataset generation process: (1) continuous motion of a virtual prosthetics hand (VR-hand) and motion timing bar are displayed to a subject; (2) the subject contracts his/her muscles following the VR-hand motion; and (3) sEMG signals and joint angles of VR-hand are measured and saved as the learning dataset. This system does not need to measure actual joint angles. To demonstrate the effectiveness of this learning system, RMS error of joint angle estimations are presented in cases of a motion set with 8 patterns for a healthy subject, and a motion set with 4 patterns for a right forearm amputee.

To display three-directional forces at a user's multiple fingertips and to allow the user to grasp a small virtual object, we previously developed a side-faced-type multi-fingered haptic interface. This haptic interface consists of a five-fingered haptic hand and an arm, and the haptic interface is located on the side of the user's body. Therefore, there is a risk that the haptic hand and the user's hand will collide while the user manipulates the haptic interface. In this paper, we realized a control system for collision avoidance for a side-faced-type multi-fingered haptic interface, and present experimental results demonstrating its validity.

This paper presents the design of tool-type devices for a multifingered Haptic Interface Robot (HIRO), and summarizes the experimental results. HIRO consists of a robot arm with a five-fingered hand to which a variety of tools can be attached. The system is able to present the force sensation of many tool-type devices. In the medical field, manufacturing industry, and other fields, there are tools of a variety of shapes with a range of uses, and a haptic interface that can present the force sensation for many tools will be important for virtual training systems. HIRO has five fingers, and thus, we must clarify how many fingers need to be connected to the tool-type device and which fingers should be used for the connection. Solving these problems is important with regard to presenting an operator the force feeling through the tool-type device. To solve these problems, we propose an optimal connection method from the mobility and singularity points of view, and we have developed the tool-type devices for HIRO based on the proposed method. We describe here several experiments that were carried out to investigate the performance of the developed devices.

For a mobile robot using an encoder to measure the travel distance, a critical cause inducing the error is the slip of the wheel. The slippage not only causes the distance error, but also increases the overall energy consumption and decreases the locomotion performance. To cope with these effects without spending extra sensors or high processing load, the slippage control system composed of two fuzzy modules, namely the trajectory estimator and velocity controller, has been developed based on experimental data collected from encoders and a motion capture system. The control system applied the cross-coupling control technique by employing the estimated velocity from the estimator as a part of an input for the velocity controller of four wheels. This way, the simple yet effective slippage control system is feasible. Promising results verify the potential of the system. Thus, this initial research provides the framework to develop the competent slippage control system for our pruning robot.

Students studying to become therapists have few opportunities for repeated training for the rehabilitation of contracture joints. This paper proposes the concept of a robot hand system for repeated rehabilitation training. A novel robot hand and artificial skin are developed in collaboration with doctors and therapists. Development of the robot hand is based on new design concepts aimed at imitating a human hand with a disability. The joint torque of a disabled person can be estimated by distributed tactile sensors. A model of contracture joints with tendon adhesion is introduced. The robot hand in imitation of contracture joints is governed by the force control based on torque control. The effectiveness of the proposed method is demonstrated experimentally.

This paper presents the design and control of a newly developed five-fingered haptic interface robot named HIRO II. The developed haptic interface can present force and tactile feeling to the five fingertips of the human hand. Its mechanism consists of a 6 degree of freedom (DOF) arm and a 15 DOF hand. The interface is placed opposite the human hand, which ensures safety and freedom of movement, but this arrangement leads to difficulty in designing and controlling the haptic interface, which should accurately track the fingertip positions of the operator. A design concept and optimum haptic finger layout, which maximizes the design performance index is presented. The design performance index consists of the product space between the operator's finger and the hapic finger, and the opposability of the thumb and fingers. Moreover, in order to reduce the feeling of uneasiness in the operator, a mixed control method consisting of a finger-force control and an arm position control intended to maximize the control performance index, which consists of the hand manipulability measure and the norm of the arm-joint angle vector is proposed. The experimental results demonstrate the high potential of the multifingered haptic interface robot HIRO II+utilizing the mixed control method.

Haptic interfaces presenting force and tactile feeling at human fingertips are used in the area of telemanipulation of robots, simulation and design in virtual reality environments, educational training, and so on. Multi-fingered haptic interface is required to be safe, to work in wide operation space, and to present not only force at contact points but also weight feeling of virtual objects, to have no oppressive feeling when it is attached to humans, and to have no weight feeling of itself. The paper presents two control methods for the multifingered haptic interface, which is a redundant robot. First is redundant force control, which takes into account moments at tip of an interface arm. The second is a combination of the force control of the fingers and the position control of the arm, which optimizes the manipulability of haptic hand and minimizes variation of joint angles of the interface arm. Experimental results of free space and constrained space are shown. The control methods are well suited not only for the multi-fingered haptic interface but also for the multi-fingered robot hand for grasping and manipulating an object

This paper presents a newly developed anthropomorphic robot hand called KH Hand type S, which has high potential of dexterous manipulation and displaying hand shape, and its master slave system using the bilateral controller for five-fingers robot hand. The robot hand is improved by reducing the weight, the backlash of transmission, and the friction between gears by using elastic body. Expression of Japanese finger alphabet is shown. In order to demonstrate the dexterous grasping and manipulating an object, the experiment of peg-in-hole task controlled by bilateral controller is shown. These results denote that the KH Hand type S has a high potential to perform dexterous object manipulation like the human hand.

Medical education has a strong need for palpation training. Haptic sense is indispensable for the detection of subsurface tumor. A virtual reality (VR) training for breast palpation simulation was created utilizing the newly designed multi-fingered haptic interface robot (HIRO). The simulation allows the user to perform breast palpation. A realistic model of the breast was developed and a physically based modeling is achieved by using a finite element method (FEM) that provides correct reaction forces and deformations of a virtual deformable object. A VR medical application system for breast palpation using HIRO was developed and examined in a real-time experiment.

Haptic interfaces, which present force and tactile feeling at human fingertips, are utilized in the aria of tele-manipulation of robots, simulation and design in virtual reality environments, educational training, and so on. The haptic interface is demanded to be safe, to work in wide operation space, and to present not only force at contact points but also weight feeling of virtual objects, to have no oppressive feeling when it is attached to humans, and to have no weight feeling of itself. This paper presents a control architecture of the developed multi-fingered haptic interface, named Gifu Haptic Interface. The haptic interface was designed to be completely safe and to be similar to the human upper limb in shape and motion ability. The interface is placed opposed to the human hand, which brings safety and no oppressive feeling, but causes difficulty in controlling the haptic interface because it should follow the hand poses of the operator. Two control methods of the haptic fingers are tested and two approaches to oppose the interface hand to the human hand are studied. A computer graphics simulation and experiments are also presented.

A virtual robot teaching that consists of human demonstration and motion-intention analysis in a virtual reality environment is an advanced technology of automatic programming for multi-fingered robots. For the virtual hand model displayed on-screen, a human-hand model is better than a robot-hand model in terms of teaching time and a stable manipulation of virtual object. However, it may occurs that a robot cannot grasp an object at a teaching position and orientation of the robot hand because the geometrical size and motional function of the robot hand is not the same as that of human hand. To solve this problem, we propose a virtual teaching based on hand manipulability, in which a position and orientation of the robot hand is determined so as to maximize a manipulability of the robot hand on the condition that the robot grasps the object at the teaching contact points on the object. Experimental results of a pick-and-place task are shown to demonstrate the effectiveness of the proposed method.

Several forces are always exerted on locomotion systems, such as inertial forces, gravitational forces and ground reaction forces. Among these, we focus on the ground reaction forces in order to consider the balance control of a simple two-link legged robot model in the sagittal plane, which contains one actuator at the ankle and two force sensors on the sole. To maintain the balance, it is necessary that the ground reaction forces are kept positive at both ends of the foot, i.e. the heel and the toe. To achieve this, we design two control laws for each ground reaction force. By alternatively switching them, the standing posture can be maintained. Examining the behavior in the phase plane, the stability of the control laws are considered. Furthermore, we also study posture changes caused by stationary external forces in the horizontal direction. Introducing a torque input that changes on a large time scale, we realize a postural adjustment whereby the body is adaptively inclined to the opposite direction of the external force. By computer simulations, we confirm the convergence of such a posture adjustment.

This paper presents a symbolic analysis of the base parameters for closed-chain robots by means of the completion procedure in polynomial ideal theory. The regressor of the robot dynamics is represented as a matrix of multivariate polynomials and reduced to the "normal form" based on Buchbergers' algorithm by constructing reduced Grobner bases from kinematic constraint equations. The linear independence of column vectors of the reduced regressor is examined by the Gauss-Jordan elimination method. The original dynamic parameters are regrouped and some of them are eliminated based on the results. This method derives all the base parameters systematically in theory. Two examples are presented to illustrate the merits of the new method.

This paper presents a new computational algorithm of the model-based adaptive manipulator control, adopting the basic method proposed by Slotine and Li (1987). The manipulator regressor that is represented by an actual velocity vector and a reference velocity vector is computed explicitly by a recursive algorithm based on the Newton-Euler formulation. The proposed algorithm is more efficient than other methods for a manipulator with six or fewer joints. An experimental result is also presented to show the possibility of an adaptive controller having a single DSP for a robot manipulator with six degrees of freedom.

The authors present a manipulator terminal-link parameter estimation method. The estimation equations are linear in the unknown terminal-link parameters. These unknown parameters are estimated using an instrument variable method (IVM). It is verified theoretically and experimentally that the IVM asymptotically yields consistent estimates. The number of operations required to estimate the terminal-link parameters of a manipulator having six degrees of freedom is about 1800 multiplications and 1500 additions using the recursive IVM at k=5, where k is the sampling number.>