Robust multivariable control of active magnetic bearings

A non-linear model of a Rolls-Royce turbo machine´s rotor supported by active magnetic bearings (AMBs) is presented. A multiobjective genetic algorithm (MOGA) is used as a search and optimisation tool for designing AMB controllers. The H_∞ loop-shaping design is used to guarantee the stability and robustness of the controller, and a MOGA is used to select weighting function structure and parameters to ensure certain standards of system performance. The optimisation is performed directly on the non-linear model to ensure that realistic controllers are produced.