A dynamic feedback tracking design for systems with friction using the LMI formulation

This paper addresses an extended output feedback positioning tracking of a servo-system with friction. It is based on LuGre friction observer dynamics with fixed model parameters. Our design features a global asymptotic stability of the tracking error while sustaining desired transient specifications using dual conditions of strictly positive real (SPR) one and exponential stability margin. These latter have to be fixed with respect to specific pole placement limiting fast controller dynamics. Our full-order dynamic output feedback controller is composed of two components: the first deals with the tracking context and the second represents a correction term in the observer from the position and velocity errors. The subsequent linear state space controller matrices are found by using the linear matrix inequality (LMI) approach. Simulation results illustrate the effectiveness of the proposed compensator.