Robust control of discrete systems

Abstract

In this Chapter, we analyze reduced-order adaptive control schemes for linear discrete plants including bounded disturbances and/or unmodeled dynamics. Three adaptation mechanisms are presented and compared. It can be concluded that for uniformly bounded input, reduced-order controllers yield stable performance but within a conservative region of attraction. This region contains all signals which will converge to target sets around the equilibrium for perfect adaptive tracking. The size of the target sets depend on the adaptation gain, the mode separation ratio, the adaptation mechanism, the external bounded disturbance and finally the magnitude and periodicity of the reference input. Simulation results indicate that the design parameters can be adjusted to achieve good performance, under various operating conditions.