Tracking Error Constrained Terminal Sliding Mode Control for Ball-Screw Driven Motion Systems with State Observer

In this study, a predefined performance constrained nonsingular sliding mode control is proposed, in which the assumed feedforward dynamic method and super-twisting state observer are combined to compensate unknown dynamics and estimate unmeasured velocity signal in the ball-screw driven servo system. Based on nonsingular sliding mode control, a new and higher convenient tracking error constraint method has been developed over the conventional complex constraint method. Next, a super-twisting state observer to exhibit higher estimation performance than the high-gain state observer is also considered. The finite convergence time is derived from the Lyapunov stability condition. Simulation and experiment results for the XY table system are presented to demonstrate the outstanding control performance of the proposed control scheme.