Feedback Linearization and Disturbance Observer Based Control with Anti-Windup for a Class of Variable Stiffness Actuators Based on Lever Mechanisms

摘要

In this paper, a robust tracking controller based on feedback linearization and disturbance observer is designed for a class of variable stiffness actuators (VSAs) based on the lever mechanisms. The CompAct-VSA developed at Italian Institute of Technology is chosen as the study object. Firstly, for the dynamic model of the CompAct-VSA in the presence of parametric uncertainties, unknown bounded friction torques and unknown bounded external disturbance, by using the coordinate transformations and feedback linearization, the state space model of the CompAct-VSA system is transformed into an uncertain linear system. Subsequently, a robust tracking control scheme is designed for the CompAct-VSA system. Furthermore, an anti-windup scheme is added to the disturbance observer to deal with the control input saturation problem. Simulation studies demonstrate the effectiveness of the proposed robust tracking control scheme.