Active disturbance rejection trajectory tracking control for pneumatic servo system based on backstepping approach

This paper presents an improved active disturbance rejection controller to study the trajectory tracking problem of a pneumatic servo system. It is a challenging job to track a given trajectory for pneumatic system with strong nonlinearity. The designed active disturbance rejection controller consists of tracking differentiator, extended state observer and nonlinear controller. Tracking differentiator is designed to arrange a transition process for the given signal and get its corresponding differential signal. Extended state observer has advantages in observing states and estimating the nonlinear part of system. Moreover, a nonlinear controller is derived on the basis of backstepping approach. Finally, simulation results indicate the capabilities of the proposed method.