Q-parametrization//spl mu/-control of an electromagnetic suspension system

This paper presents a new controller design methodology for an electromagnetic suspension system using the Q-parametrization theory and μ-analysis, in order to achieve both robust stability and robust performance. The set of all stabilizing controllers of the plant is characterized by a free parameter Q. This free parameter is chosen through optimization such that both robust stability and robust performance are achieved. We describe the experimental setup and give a mathematical model for the electromagnetic suspension system (ESS) used in this research. We explain the Q-parametrization control with μ-analysis of a given plant, formulate the control problem as an optimization problem in the free parameter and with robust stability and nominal performance as constraints, and assess robust performance with μ. The proposed controller design methodology is applied to a simple SISO ESS employed in this research and a fifth order controller which achieves both robust stability and robust performance is obtained. Finally, several simulation and experimental results are presented.