Yasunori Kawai

Bilateral teleoperation of wheeled mobile robot with time delay using virtual image robot

This paper considers the bilateral teleoperation of wheeled mobile robot with time delay using the virtual image robot. In this paper, we introduce the virtual image robot as a master robot. The human operator commands the virtual image robot, the slave wheeled mobile robot tracks the motion of the virtual image robot. The kinematics and dynamics of master/slave robots is considered. The scattering theory and passivity based control schemes for bilateral teleoperation is applied, the control law is proposed. In the simulation, the performance of the proposed bilateral teleoperation system is verified using wheeled mobile robots.

Co-contraction of antagonist bi-articular muscles for tracking control of human limb

This paper considers muscle contraction dynamics during co-contraction of antagonist bi-articular muscles for tracking control of a human limb. Co-contraction of antagonist muscles play an important role for joint stiffness and stability and experimental results show the existence of co-contraction during volitional movements. This paper shows the role of co-contraction by using three pairs of bi-articular antagonistic muscles. It is indicated that the co-contraction is useful not only to compensate the stability of the joint, but also to control the output force direction. The main contribution is to model the co-contraction control of human limb by using three pairs of bi-articular antagonistic muscles. A robust integral of the sign of the error (RISE) controller is shown to yield semi-global asymptotic tracking. The tracking control performance and stability are verified in the simulation.

A study of bilateral teleoperation with time delay using command governor

This paper considers the bilateral teleoperation with time delay. The stability of the bilateral teleoperation is compensated by the local controllers. However, the constraints violation occurs in the implementation of the real system. In this paper, the command governor is applied to the bilateral teleoperation, which modifies the command to avoid constraint violations. In the simulation, the performance of the proposed bilateral teleoperation system is verified using a single-degree of freedom master/slave system.

Experiment of virtual tug-of-war via internet with multilateral telecontrol

Social communication created on the Internet has realized a communication form mankind never experienced in which thousands or millions of people share each other images and sounds. In this report, we present the results of virtual tug-of-war experiments using multilateral telecontrol in which clients in eight sites throughout Japan share the force sense.

Educational Joint Project between NCT and TUT in Japan Using Tele-Control System

This paper presents an educational research project based on a collaboration between the National Colleges of Technology (NCT) and the Toyohashi University of Technology (TUT) in Japan. First, we constructed a telecontrol system that can work on the Internet for teleoperation experiments. To transmit realistic-looking environmental information, we implemented a 3D scenography system. Here we describe our experimental apparatuses and the control experiments performed as educational experiences for NCT students. In addition, to enhance the effectiveness of the educational experience and improve the proposed telecontrol system, we designed a questionnaire for operators to fill out after they finished the experiments. In this paper, we discuss the contents of the proposed educational system and the improvement of learning motivation that we believe could result from this project.

Experimental implementation of bilateral teleoperation with time delay using command governor

This paper considers the implementation of the bilateral teleoperation with time delay using the command governor. The command governor can avoid the constraints violation. However, the command governor is formulated by the quadratic programming, it is hard to solve the problem in the sampling time. In this paper, a algorithm is proposed to decrease the computational cost. In the experiment, the performance of the proposed bilateral teleoperation system is verified using a single-degree of freedom master/slave system.

Co-contraction of antagonist muscles of human limb using neural network-based control

This paper considers co-contraction of antagonist muscles of human limb using neural network (NN)-based control. Some experimental results indicate that the antagonist muscle and agonist muscle work at the same time during the knee extension and flexion, then it is called co-contraction. However, control laws to adjust electrical impulses for the antagonist muscle by neuromuscular electrical stimulation (NMES) are almost not shown in previous researches. This paper proposes that the control of agonist muscle and antagonist muscle is controlled independently. Moreover, NN-based control is applied to control of antagonist muscle, because the learning components is needed for the unknown disturbances. The set-point regulation control and trajectory tracking control are implemented with the no co-contraction and NN-based co-contraction. It is shown that the co-contraction is useful to the convergence of the joint angle by the attenuation of the overshoot.

Control design of client using mixed sensitivity problem for multilateral teleoperation system

This paper considers a control design of client side using mixed sensitivity problem for multilateral teleoperation system. For multilateral teleoperation system, only the client side is considered. The 1-DOF (degree of freedom) paddle system as a client side is used. The paddle system is modeled as linear system, the mixed sensitivity problem is applied. The weighting functions are designed to satisfy the control specification. The stability and control performance are verified by simulations and experiments. It can be shown that the position error between client side and teleoperator converges to zero, the teleoperation system is stable for time delays.

RISE control for 2DOF human lower limb with antagonistic bi-articular muscles

This paper considers RISE control for two-degree-of-freedom (2DOF) human lower limb with antagonistic bi-articular muscles. The antagonistic bi-articular muscles straddle the waist joint and the knee joint in the lower limb. Because the nonlinear model of the lower limb of the human body is uncertain, a robust control method is developed yield semiglobal asymptotic tracking. Simulation results indicate that the torques in joint 2 of the 2DOF lower limb is lower than the previous method, because of antagonistic bi-articular muscles. It is verified that the 2DOF lower limb can move to the desired position in the presence of unmodeled bounded disturbances.

Passivity and RISE based robust control for bilateral teleoperation system with communication delay

In this paper, a method for passivity- and robust integral of the sign of the error (RISE)-based control of a nonlinear teleoperation system with communication delays is proposed. This control strategy can accurately achieve coordinate positioning under conditions with viscous friction and unmodeled effects compensation errors, and its stability condition is independent of robot model parameter uncertainties and time delay. Using passivity-based stability analysis, the stability and tracking performance of this system are demonstrated, and experimental trials are performed to verify its effectiveness.