Resonance tracking in a squeeze-film levitation device

An adaptive method, with which an excitation frequency is continuously varied to obtain maximal oscillation levels, is developed. It is shown that this approach yields the best mechanical efficiency and it is thus essential when the available input power is restricted. The method is demonstrated on a specific apparatus, a squeeze-film levitation device, to obtain maximal levitation height of a floating object. The proposed method uses a minimal amount of frequency dither to revive an identification process that is otherwise singular. With this identified model, the algorithm seeks the best momentary excitation frequency. The algorithm is validated in a simulation and on dedicated experimental apparatus.