H∞H∞ control of active magnetic suspension

A robust control of an active magnetic suspension requires an accurate plant model and proper model uncertainties. Moreover, the selection of control design performance weighting functions is not straightforward. In this paper, the design of a centralized H∞H∞ controller of an active magnetic suspension is considered. Two design approaches are examined: an H∞H∞ loop-shaping control design procedure and a signal-based H∞H∞ control. The tuning of the design performance functions is carried out applying a genetic algorithm. The robust stability of the gain-scheduled H∞H∞ controller is verified in the presence of real parametric and non-parametric frequency-dependent uncertainties. Accurate models of the system and its uncertainties can be obtained using engineering models and frequency response functions of the test-rig. Finally, simulations and experimental results confirm the effectiveness of the signal-based H∞H∞ approach.