A sampled-data control scheme for stabilization of systems with unmodeled high-frequency dynamics

The output feedback stabilization problem is considered for linear sampled-data control systems in the presence of unmodeled high-frequency dynamics. Sufficient conditions for stabilization of such systems were given by M. Vidyasagar (1985) for strictly proper systems. This paper extends the class of systems in order to include the proper systems case and proposes a conceptually novel digital control scheme. In this scheme, the control law, based on the reduced-order system, is applied to the full system only during a short fraction of the sampling period. During the second part of the sampling period the control is taken equal to zero such that, without control, the neglected fast states have sufficient time to converge to their equilibrium point