This thesis has proposed a new optimal decentralized controller design method for solving the tracking and disturbance rejection problems for the class of large scale LTI systems, using only low order decentralized controllers. The objective of the controller is to reject system constant disturbances and track constant reference signals by using an optimal decentralized control procedure. The proposed controller also has the property that if a sensor actuator failure occurs, thereby producing an unstable pole at the origin, that there is time for a repair to be carried out before massive destruction occurs. The proposed optimal controller also has the property that it is strongly robust as compared to the standard centralized LQR-Observer. In particular, the proposed controller can have the property of being some 5 orders of magnitude more robust than the standard LQR-Observer controller. |