Discrete-time robust tracking control using a state space disturbance observer

This paper considers the design of a discrete-time robust tracking control system which consists of a state space disturbance observer, a state estimator, and a state feedback controller. A new discrete-time state space disturbance observer is proposed not requiring modeling of disturbances. Through the results of applications, it is shown that the proposed method is very effective to compensate a variety of disturbances and to improve the performance of a tracking control system in the existence of external disturbances. It is also observed that the proposed state space disturbance observer allows more accurate state estimation in the existence of modeling error and disturbances