Robust control of pneumatic actuators based on a simplified model with delayed input

Due to frictions and air compressibility, the dynamics of pneumatic actuators is often described by a complex fourth-order non linear model. Therefore, simplifying the model of pneumatic actuators is of prime interest to design a controller. In this paper a simple second order model is proposed by modeling the pressure dynamics with a pure time delay on the control input. The Artstein transformation is applied to this model to get a delay-free second order system. Then the delay-free system is stabilized using a robust nonlinear controller. The relevance of the proposed approach is demonstrated through experimental tests.