Robust output feedback stabilization of a field-sensed magnetic suspension system

The magnetic suspension system (MSS) is very important in many engineering applications. This paper proposes the dynamic output feedback control of a field-sensed MSS (FSMSS). The mathematical model of the MSS is described by discrete-time systems. Ideally, the coefficients of a nominal polynomial precisely determine the Schur stability. But in reality, the coefficients may contain uncertainties due to such reasons as computational errors. Therefore, there is a need to address the problem of robust stability of discrete-time systems. In this paper, we estimate the size of allowable perturbation in polynomial coefficient space for the output feedback control of the MSS. The mathematical model is described by discrete-time systems. The ℓ^∞-norm and a lower bound for the size of the Schur stability hypercube are provided in this paper.