A Robust Finite-Time Control Method for Two-Joint Flexible Manipulator

Abstract

There are some problems with the double-joint flexible robotic manipulator itself, and the classic PID control method has the defect of slow convergence rate. Therefore, in order to deal with the defect of slow convergence rate of classical PID control methods in the control problem of dual-joint flexible manipulators, a robust finite-time control method is proposed. A two-stage finite-time sliding mode surface with fast convergence characteristics is designed, which the manipulator moves at a uniform speed when the system state is far from the equilibrium point, and the fractional-order feedback is designed to achieve finite-time control when the system state is approaching the equilibrium point, thereby maintaining a fast convergence rate of the system during the full control process. Aiming at the disturbance problems such as flexible vibration, external disturbance, and model uncertainty in the control process, an improved sign function term is designed to suppress them and avoid high-frequency oscillations near the equilibrium point, and a robust controller is further designed to achieve the convergence of the system state under disturbance conditions. The proposed method is verified by Lyapunov stability theory, numerical simulation and physical simulation, and the experimental results show that the proposed robust finite-time control method improves the convergence rate by more than 50% compared with the classical PID method, and achieves fast, stable and precise control objectives.