Vibration Suppression and Adaptive Fault-Tolerant Control for Three-Dimensional Flexible Rotating Manipulator With Input Signal Constraints

Based on a three-dimensional flexible, rotating manipulator, this paper is dedicated to the issue of vibration suppression and angle planning subject to actuator failures and input signal constraints. Considering that a flexible link belongs to a distributed parameter system, the motion model is obtained by Hamilton's principle and described by partial differential equations (PDEs). A novel fault-tolerant control law is proposed to eliminate the elastic deflection and vibration of the flexible link and to follow the desired angle of the rotating base and the manipulator with the appearance of actuator failures. The adaptive operator based on projection mapping is adopted to estimate the loss of the actuator. In addition, the hyperbolic tangent function is employed to constrain the input signal so that it is within an adjustable interval. The Lyapunov's method and LaSalle invariance principle are applied to prove the stability and convergence of the closed-loop system. The simulation results are provided to demonstrate the effectiveness of the proposed method.