Study On Control For Robot Teleoperation Systems With Time-varying Delays

Thanks to the development of social economy, science and technology, robot teleoperation has been greatly utilized in many aspects and fields, namely, deep sea work, space exploration, nuclear facilities, etc. Its great performance in economic cost reduction and operator safety assurance has enhanced its competitiveness in the future. The success of the application of robot teleoperation has increasingly exhibited its tremendous research value, which brings robot teleoperation a great popularity in the field of control.The dynamics equation of robot teleoperation system, however, has the problems of nonlinearity and uncertainty, especially the problem of communication delay. These problems greatly affect the stability and operating performance of robot teleoperation system. According to these problems, the thesis will focus on the discussion of the following aspects.Firstly, the dynamic model of robot teleoperation system is obtained through the introduction of Lagrange method. To facilitate the analysis of the influence of time delay on system stability and operating performance, two-port network model equal to robot teleoperation system will be introduced. Then the influence on the stability and transparency generated by time delays will be analyzed based on two-port network model. The analyzed result proves the fact that time delay is the radical cause of the system instability and the decrease of transparency.Secondly, concerning the varying time delay of robot teleoperation system, synchronization control for teleoperation system is converted to the problem of H_∞ control for an uncertain linear time-delay system by using feedback linearization method, where the uncertainty is used to model the dynamics induced by the time-varying part of the delay. A sufficient condition of the H_∞ performance for the teleoperation system is presented by applying the Lyapunov-Krasovskii function and the integral inequality method. Then the design method of H_∞ controller is given out by using linear matrix inequality method, which realize the synchronization control for teleoperation system, and simulations are presented to show the effectiveness of the proposed method.Thirdly, the uncertain time-delay system model converted from robot teleoperation system through feedback linearization will be augmented. Then quadratic performance index is given out. According to the augmented uncertain time-delay system and quadratic performance index, synchronization control for robot teleoperation is described as the problem of guaranteed cost control. Furthermore, the robust performance of the system is analyzed and the design method of guaranteed cost controller is given out by means of linear matrix inequality. Finally, simulations are presented to show the effectiveness of the proposed method and that synchronization error has smaller fluctuations, and can converge more quickly to zero state.