Four-Channel Sliding Mode Control for Haptic Teleoperation System with Disturbance in Contact with Adaptive Stiffness Environments

In the haptic teleoperation system, the traditional four-channel architecture is widely used in various fields because of its transparency. However, with the nonlinearity of the robot and the uncertain external environment, the architecture may no longer achieve good control accuracy. This paper proposes a new four-channel sliding mode control for haptic teleoperation system with disturbance. Considering the disturbance and external environmental impedance, the displacement and force information of the master and slave are transmitted to each other through the communication channel. On this basis, the observer-based sliding mode control is designed between master and slave. Thus the good tracking effect of displacement and torque is realized, the phenomenon of force flutter is reduced, and the estimation and compensation of disturbance are completed. Finally, the stability of the closed-loop system is analyzed by the Lyapunov method. It is verified that the proposed control scheme has good control performance via comparative simulations.