A Novel Prescribed Performance Controller with Unknown Dead-Zone and Impactive Disturbance

This paper investigates a robust prescribed performance control scheme for motion control system with unknown dead-zone input and impactive disturbance. The unknown dead-zone input is divided into a linear part and a disturb part firstly. A smooth dead-zone inverse is constructed to compensate the influence. Subsequently, a novel error transform function is proposed for the limitation that the former prescribed performance control scheme cannot tolerate the impact disturbance. A robust control scheme with prescribed convergence rate is derived with the help of back-stepping technique and the dead-zone parameters is estimated by a designed adaptive law. Lyapunov function is employed to improve the stability of the system. Moreover, a fast finite-time-converge sliding mode differentiator is introduced to estimate the unavailable states of the motion control system. Finally, a two-link robot arm with unknown dead-zone input and high impact is employed to demonstrate the robustness and effectiveness of the control scheme.