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 /spl mu/-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 /spl mu/-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 /spl mu/. 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.