The objective of this study is to propose a discrete-time backstepping sliding mode control technique (BSMC) for regulating a pneumatic artificial muscle (PAM)-based exoskeleton used in rehabilitating human lower extremities. The PAM system is challenging to control due to its high nonlinearity, parameter uncertainty, and significant delay resulting from the use of compressed air. The backstepping control method is a recursive approach that systematically designs control laws for nonlinear and complicated systems. This technique ensures stable and robust system control, even in uncertain circumstances. Furthermore, the backstepping controller is capable of handling high-order systems and guaranteeing high-precision tracking of a desired trajectory. The incorporation of sliding mode control is aimed at enhancing the performance of the robot PAM system by reducing chattering and reaching time. The algorithm employs Lyapunov functions and sliding surfaces to design the control signal for operating the system. The study concludes with experimental scenarios demonstrating the effectiveness of the proposed approach.
Keyword
Pneumatic Artificial Muscle, Backstepping, Sliding Mode Control
