Sliding Mode Control of Three-Links Spatial Robot Based on Low-Pass Filter

In order to improve the trajectory tracking control performance of three-links spatial robot, a new sliding mode control method with low-pass filter is proposed in this paper. Due to Fast response speed and invariant to system parameter perturbation and external disturbance uncertainties, traditional sliding mode control can assure the asymptotic stability of the system, but its disadvantage is that the control itself will cause system strong chattering. Therefore, low pass filter is introduced on base of the traditional sliding mode control method, the control law can guarantee fast convergence of trajectory tracking error as well as robustness for external disturbances and parameter uncertainties. The stability of the system is proved by Lyapunov theorem. Finally the simulation is carried out for the three-links spatial robot, the simulation results show that the proposed method is effective to improve the robot tracking control performance in the presence of model error and external disturbance, and weaken the chattering to a certain extent.