Nonlinear Active Disturbance Rejection Control for Pneumatic Artificial Muscles

In this paper, a nonlinear active disturbance control (ADRC) method for Pneumatic Artificial Muscles (PAMs) system is designed, which effectively solves the strong coupling and uncertainty problems in PAMs system, and achieves the control objective in the presence of external perturbations. Firstly, the state space expression of Pneumatic Artificial Muscles is rewritten, and a new system state variable is added. Further, the nonlinear extended state observer (NLESO) is introduced to estimate the total perturbations and outputs in the system. Based on the NLESO observations, the error compensation controller is designed, and sufficient conditions are provided to ensure the overall controlled system’s stability. Finally, simulation experiments are conducted to verify the effectiveness and robustness of the proposed method.