LuGre model-based friction compensation and positioning control for a pneumatic actuator using multi-objective output-feedback control via LMI optimization

This paper deals with a high-friction pneumatic actuator positioning technique based on a LuGre friction closed-loop observer dynamics. The main purpose of the technique is to establish the stability condition by using the passivity of interconnected linear and nonlinear subsystems dealing with the varying and uncertain parametrization of friction modeling and exogenous bounded inputs resulting from the force-loop dynamics. With this formulation, we succeed in designing a full-order dynamic feedback which ensures exponential stabilization and additional multi-objective constraints (an H∞H∞ criterion and a closed-loop pole location). These conditions are expressed in terms of linear matrix inequalities (LMIs). The formulation is therefore numerically tractable via LMI optimization. The performances are validated experimentally on a pneumatic plant operating under a high level of friction. The robust LuGre model-based friction compensator is experimentally compared to other friction compensation and position control schemes.