Stabilization of Uncertain Systems using State Detection and Application to a Maglev Vehicle

We present a deterministic treatment for the control of a class of systems with time-varying uncertainties. For the controller design we assume only that the uncertainties lie within some prescribed sets. The controller, based on the knowledge of the present state, guarantees desired performance of the system, including uniform boundedness and uniform ultimate boundedness. If, however, only output instead of state is available for the controller, the construction of a suitable observer is introduced. The resulting plant-observer-controller system is shown to preserve the above-mentioned desired performance. The theoretical result is illustrated by an application to the suspension control of a Maglev (magnetically levitated) Vehicle.