High-precision tracking control for high-order fully actuated motion control systems with deadzone nonlinearity

This paper studies the high-precision tracking control problem of a class of motion control systems (MCSs) with deadzone characteristic, system uncertainties and external disturbances. First, a higher-order fully actuated (HOFA) tracking error control model for MCSs is established, and the system uncertainties are divided into the known inherent nonlinear part and an unknown parameter perturbation part. Then, a deadzone inverse model is applied to precompensate the inherent part, and the unknown part and external disturbances are treated as equivalent-input-disturbance (EID) on the control input side. Second, an intermediate variable-based EID (IVEID) is designed to obtain more accurate EID estimation by adjusting parameters, and an improved MPC (IMPC) method is constructed to suppress the effect of lumped disturbance. The terminal constraint set is maximized to expand the system stability range and accelerate system convergence, while the terminal penalty is minimized to improve optimization efficiency. Finally, numerical simulation on a single linkage robotic arm and experiment on a pair-drag platform demonstrate that the proposed method achieves at least a 30% improvement in comprehensive performance compared to the improved EID method, which verifies its effectiveness and superiority.