In this paper, a human-symbiotic robot is described to realize human safety, impact force absorbing and task fulfillment. The robot consists of an arm covered with soft materials and hybrid joints, which can be put into active or passive mode as needed. In an unexpected or expected collision with human, the arising impulse force is attenuated effectively by the physical model formed with the hybrid joint and the soft material. Owing to the displacement movement of the link when the joint is passive, a recovery control algorithm has been developed for the end-effector to maintain its desired task position after the collision. Simulation results confirm that the proposed physical model is suitable for robot working in the human-robot symbiotic environment and the control method is useful for robot's task fulfillment.

Usually there exist joint stops in a manipulator due to the mechanical structure of joints. In conventional manipulators, a collision between an arm and the structural joint stop is avoided by barriers from both software and electronic hardware. Comparing to these conventional manipulators, human utilizes structural joint stops usefully in many manipulations, especially in hyper dynamic manipulations such as golf swing. A basic concept and general method to utilize the structural joint stop in a manipulator, aiming at improving the dynamic capability of the manipulator in a large extent by simple and smart structure have been given in our previous work. To show the feasibility of the proposal, a hyper dynamic manipulator utilizing joint stops has been fabricated and fundamental experiments(see video) have been carried out. Experimental results have shown the important role of the joint stop, to realize an efficient hyper dynamic manipulation while in a smart structure. This paper describes the developed prototype and experimental results.

A sensing system using sonar ring for mobile robot capable of rapid detection and avoidance of obstacles has been developed. In the system, a method of firing all ultrasonic sensors on a sonar ring simultaneously is used and to eliminate error data due to crosstalks in the simultaneous firing, a filtering method based on pattern matching using neural network is used. To show the advantage of this method, a prototype of sensing system with 24 sonar sensors is fabricated. By installing the system to mobile robot, a scanning rate up to 50 Hz of panoramic detection is achieved. The experimental results showed that a rapid navigation of mobile robot in a real environment becomes possible. This paper describes the basic concept, the method for sensing and avoidance of obstacles, configuration of the developed sensor system and experimental results of obstacle detection and avoidance.

Usually the revolute joint of a manipulator cannot rotate all around, that is, in a range larger than 360 degree and it is limited by a mechanical element, the so called "joint stop". In conventional manipulators, a collision between an arm and the joint stop is avoided by barriers from both software and electronic hardware. Comparing to those conventional manipulators, human utilizes structural joint stop usefully in many manipulations, especially in hyper dynamic manipulations. In this paper, we propose a general utilization of structural joint stop in a manipulator to improve the capability of the manipulator in a large extent by a simple modification of the structure of joint. This paper gives the basic idea for utilizing structural joint stop in a manipulator, expected effects of the proposal, the method how to utilize the joint stop and simulation results.

Trajectory of an underactuated manipulator is usually generated according to both kinematics and dynamics of the manipulator, different to that of conventional manipulator. The real trajectory by a real system may differ greatly from the trajectory generated from the dynamics model because there always exist errors in the dynamic model, and the feedback control is less effective in an underactuated manipulator. A method for generation of optimal trajectory for the real system of an underactuated manipulator with nonholonomic constraints is proposed. By using this method, the dynamics model of a real system can be improved by learning, and an optimal trajectory is generated according to the model improved sequentially. The effectiveness of the method is confirmed by experiment with a golf swinging robot. The implementation and experimental results obtained of the control method are described.

To construct a practical system using a mobile manipulator, a new mobile manipulator with exchangeable active/passive joints has been developed by authors. In the mobile manipulator, passive joints play an important role in absorbing the mobile positioning error and reducing the internal force passively. By utilizing the exchangeable active/passive joints, a control algorithm. for automatic insertion of a long pipe based only on the angular information of the passive joints is proposed. By implementing the algorithm to the mobile manipulator, the insertion task was performed successfully. The proposed control algorithm is described and the experimental results are shown in this paper.

The motion control skill in human hyper dynamic actions, especially in ultra high speed actions, is being investigated by authors, toward a realization of hyper dynamic manipulation by robot. As a case study, a new golf swing robot to simulate human skill of motion control, that is, multistep acceleration by dynamic coupling drive, has been proposed by us. For simplicity, a prototype consisting of one actuated joint by a direct drive motor and one passive joint with a mechanical stopper has been developed. The purpose of this research is to realize smooth control of the robot while hitting a ball. The basic method and experimental results for controlling the motion of the robot in the case of hitting a ball are described in this paper.

A new golf swing robot to simulate the human skill of motion control in a golf swing has been developed by authors. It consists of one actuated joint and one passive joint with mechanical stopper. Optimal motion planning of the robot to satisfy the boundary conditions and non-holonomic constraint introduced by the stopper under different cost functions is discussed. A general method for motion planning of such types of system is described and the results of motion planning for the golf swing robot are shown.