Experimental comparison between H∞ and H2 control for a magnetic suspension system with double flexible beam

This paper describes experimental comparison between H_∞ and H₂ control for a magnetic suspension system with double flexible beam, which simplifies both an elastic rotor and body in a magnetic bearing system. At first, the magnetic suspension system is introduced. Next, its linearized model with disturbance terms as unmodeled uncertainties is formulated in a state space form. In order to deal with the uncertainties, the generalized plant is constructed from LQ differential game theoretic point of view, which involves weighting matrices for state variables and control input and frequency weighting functions for uncertainty models. Then the control systems are designed and analyzed with both H_∞ and H₂ control in the case of fixing a generalized plant, which are implemented by a digital controller using a digital signal processor. Finally, several experiments are carried out to compare control performance and robustness