High-Precision Control for a Stewart Platform With Prescribed Disturbance-Rejection Performance.

This article presents a prescribed-performance-controller-based equivalent-input-disturbance approach (PEID) that enhances the disturbance-rejection performance of a Stewart platform. The PEID approach ensures that the disturbance-estimation error converges to a bounded region in a prescribed time. The bound of disturbance-estimation error can be chosen arbitrarily small, and the convergence time of disturbance-estimation error can be prescribed in advance. Stability conditions are derived by dividing the PEID-based control system into three subsystems, and a barrier Lyapunov function is used to design a prescribed-performance-controller-based compensator. An algorithm for designing system parameters devises state feedback and observer gains. The experiments conducted on a Stewart platform validate the effectiveness and superiority of the PEID approach.