State Estimate Based Robust Adaptive Control of a Linked Mass Spring System With Nonlinear Friction

Abstract

This paper aims to develop a state estimatebased friction fuzzy modeling and robust adaptive control techniques for controlling a class of multiple degrees of freedom (MDOF) mechanical systems. A fuzzy state estimator is proposed to estimate the state variables for friction modeling. Under some conditions, it is shown that such a state estimator guarantees the uniformly ultimate boundedness (UUB) of the estimate error. Based on system input–output data and our proposed state estimator, a robust adaptive fuzzy outputfeedback control scheme is presented to control multiple degrees of freedom system with friction. The adaptive fuzzy outputfeedback controller can guarantee the uniformly ultimate boundedness of the tracking error of the closedloop system. A typical massspring system is employed in our simulation studies. The results demonstrate that our proposed techniques in this paper have good potential in controlling nonlinear systems with uncertain friction.