Implementation of a Nonlinear Robust Controller on a Pneumatic Actuator System

This paper presents a robust discrete nonlinear active disturbance rejection controller (NADRC) for precise actuator position control in a highly nonlinear and uncertain pneumatic system. The discrete NADRC features a nonlinear extended state observer (NESO) and a feedback controller, which together estimate and compensate for unknown system dynamics and external disturbances, ensuring robustness. The controller was implemented on a pneumatic actuator in Parker Hannifin’s motion control lab. Experimental tests confirmed its tracking performance and robustness. The stability of the positioning control systems is proved using a Lyapunov method.