Model reference adaptive impedance control in lower limbs rehabilitation robot

Abstract

Active exercise can improve the rehabilitation efficacy of the paralyzed patients, while we need to consider its safety. Impedance control takes the active compliance into account, providing a safe and comfortable training environment for the patients. However, the traditional impedance control has poor robustness, so it is urgent to enhance the adaptive capability of the system. This paper proposes the model reference adaptive impedance control in lower limbs rehabilitation robot. Firstly, we introduce the system model of the lower limbs rehabilitation robot; and then we analyze the application of the impedance control in human-robot interaction; finally, we propose the adaptive impedance control based on the model reference adaptive control theory, and the control law based on Lyapunov stability is deduced. The adaptive controller can adjust the impedance control real-time, so that it can improve the robustness of the system. The effectiveness of the control algorithm is verified by experiments.