Adaptive Robust Control of One-Link Joint Actuated by Pneumatic Artificial Muscles

The pneumatic artificial muscle is very promising in the field of medical robots for its biological muscle-like and other distinct properties. But its inherent highly nonlinear features and compressibility of air bring many difficulties to high performance tracking control. This paper presents the modeling and tracking control of one-link joint driven by pneumatic artificial muscles. Due to its parametric uncertainty and unmodeled dynamics, a class of saturated adaptive robust control(SARC) laws using discontinuous projection method are applied. The proposed method synthesizes the robust control and adaptive control systematically. Both guaranteed global stability and transient performance of closed-loop system are achieved Simulation results demonstrated that the tracking error converges to the designed region in a finite time under different uncertain conditions, the effects of model uncertainties are reduced and the tracking performance is improved significantly by using the adaptation law.