Adaptive Parameter Integral Sliding Mode Control of Pneumatic Artificial Muscles in Antagonistic Configuration

This paper presents a discrete-time adaptive parameter integral sliding mode controller to improve the trajectory tracking performance of two pneumatic artificial muscles in an antagonistic configuration. The main contribution of the paper is a combination of an extended observer and an integral sliding mode controller. Therefore, the proposed controller is not only capable of adapting to the uncertainty in model parameters but also reducing the chattering phenomenon in the traditional sliding mode controller. To develop the control approach, the dynamic behavior of the system is first described by a discrete-time second-order model with two uncertain parameters. After that, an adaptive extended observer is designed for the estimation of variation of the model parameter and unknown disturbance of the system. Finally, an integral sliding mode controller combined with the extended observer is proposed to achieve a good tracking performance. Multi-scenarios experiments are carried out to verify the effectiveness of the proposed controller.