Continuous terminal sliding mode control of a 6-DOF wire-driven parallel robot

In this paper, the control problem involved in the application of 6-DOF wire-driven parallel robot is studied. Considering the system parameters' uncertainties, the terminal sliding mode control method is proposed to improve the control precision of moving platform. Furthermore, in order to decrease the effect of uncertainties on the platform tracking accuracy, both the non-singular TSM control method (NTSM) and continuous NTSM are adopted to form the sliding mode surface, and the control law is designed based on the sliding mode function. Its stability is analyzed by using Lyapunov function. A sinusoidal 3-DOF motion and a sinusoidal 2-DOF motion for the platform are simulated. Numerical simulation results show that the continuous NTSM can effectively reduce the influence of system uncertainties on tracking error and improve the platform's dynamic performances. Compared with NTSM, continuous NTSM is able to suppress the chattering phenomenon. Research done above could provide guidance and reference for the improvement of follow-up mechanisms and applications.