Dynamic Integral Sliding Mode Trajectory Tracking of Parallel Robot

Abstract

The parallel robot is a multivariable nonlinear and strongly coupled system, which is difficult to apply to controller design. In order to improve the trajectory tracking accuracy and anti-disturbance ability of the parallel robot, a control method based on improved dynamic integral sliding mode is proposed. Firstly, the dynamic model of the parallel robot is decoupled and simplified. Secondly, considering the errors caused by the decoupling and simplification of the dynamic model and the existence of external disturbances in the actual system, a sliding mode controller is introduced to improve both the trajectory tracking accuracy and the robustness of the system. The traditional sliding mode control method, however, will produce large chattering, which may damage the robot. Therefore, by constructing the second-order dynamic sliding mode surface based on the first-order linear sliding mode, the chattering can be suppressed to a great extent, while maintaining the strong robustness of the sliding mode control. Then, a Lyapunov function is constructed for stability analysis, followed by stability analysis of the closed-loop control system. Finally, an experimental platform is built for comparative experiments to verify the effectiveness and practicability of the proposed controller.