Adaptive suppression of periodic disturbances in MIMO linear systems

Suppression of unknown periodic disturbances with time-varying characteristics has many industrial applications. The purpose of this paper is to propose a robust adaptive control scheme to suppress noise-corrupted disturbances with unknown and possibly time-varying characteristics in multi-input multi-output LTI systems. First, by considering the ideal (non-adaptive) case when complete information about the characteristics of the disturbance is available, the level of the performance that can be achieved in the case of known disturbances is demonstrated. Then, the adaptive case (unknown disturbance) is examined. It is shown under what conditions the unknown periodic disturbances can be suppressed and what parameters contribute to the performance of the overall adaptive control scheme. The stability and performance of the adaptive schemes is analyzed, and finally numerical simulations are given to show the effectiveness of the proposed scheme.