Adaptive anti-disturbance controller for discrete-time multi-input multi-output systems with input delays

This paper considers the anti-disturbance problem for the discrete-time multi-input multi-output (MIMO) system with input delays, where both the disturbance and state information are unavailable. A new adaptive output feedback controller is proposed to reject the unknown disturbances of discrete-time linear MIMO systems with input delays. First, an equivalent input delay-free system of discrete-time input delay system is established to facilitate the controller design. Second, based on the Youla parameterization method, a state observer is established and a multichannel decoupling law is designed, which helps to facilitate the design of an adaptive regulator. Next, the unknown disturbance complete attenuation condition is given based on the frequency domain characteristics of the disturbance. In addition, the direct adaptive parameter algorithm with a projection operator is devised to attenuate the unknown disturbance. Finally, the effectiveness of the proposed method is verified by numerical simulation examples.