Terminal Sliding Mode Control Of Teleoperation System Based On Sliding Mode Observer

Teleoperation robot system,which can combine human intelligence with robot and expand the working ability of robot,has been widely used in various fields.In this paper,a control algorithm based on continuous fast non-singular terminal sliding mode control and fast terminal sliding mode observer is proposed.The algorithm can track the master-slave trajectory quickly and stably in the case of time-varying delay,so that the system error can converge in a finite time,and the interaction force between the slave robot and the external environment can be fully feedback to the operator.And the system has strong robustness.Firstly,the kinematics equations of the master-slave robot were established by using the exponential product method and the D-H method respectively,and the dynamics equations of the slave DENSO robot were established by using the Lagrange method,so as to build the system model of the teleoperation robot.Secondly,a continuous non-singular terminal sliding mode surface is designed to avoid the chattering problem caused by the traditional sliding mode control,and the convergence performance of the controlled system is improved by using the fast approaching rate.Then the stability of the system is analyzed based on Lyapunov theorem,and the stability condition of the system is obtained: when the upper bound of the external disturbance of the system is known,the system can be stable in a finite time.In order to verify the feasibility of the proposed algorithm,a simulation experiment is carried out.Simulation results show that the slave robot can track the master robot's trajectory quickly and stably under the control of the algorithm.Finally,considering that it is difficult to accurately obtain the velocity signals in the control process of the actual teleoperation robot system,a fast terminal sliding mode observer is designed to observe the joint velocity signals of the slave robot.The stability of the system is analyzed by using Lyapunov theorem.The results show that the system can be stable in finite time under the condition that the upper bound of the external disturbance is known.In order to prove the applicability of the proposed algorithm and observer in the practical teleoperation robot system,the control experiments of the actual teleoperation robot are carried out under the experimental conditions of no time delay,no obvious external interaction force and sometimes variable time delay,with strong external interaction force.The experimental results show that the slave robot can track the trajectory of the master robot stably even under the conditions of time-varying delay and strong external interaction force,and the operator of the master robot can feel the feedback of environmental interaction force,so the system has a strong robustness.