Discrete-Time Adaptive Compensator to Cancel State-Disturbances

Abstract In this paper, an adaptive compensator to reject unknown disturbances on state-variables of discrete-time systems is proposed. It is assumed that the plant is known but the state-variables are corrupted by disturbances and the disturbances are generated bv an unknown model. First a compensator is derived for disturbances with known model using coprime factorization. Then the compensators is extended for the case of unknown disturbance model by using an adaptive law and identifying parameters of the compensator. It is proved that all internal signals in the control system, error equations, and parameter identification law are uniformly bounded and disturbance cancellation is achieved. Computer simulations are carried out to show the effectiveness of the proposed method.