Time Delay Control Using the Outputs of a State Observer

This article shows the application of time delay control (TDC) using an observer. An observer is used to relax one of conditions for the design of TDC. It is shown that if we use an observer, we can design a time delayed controller even though an original system does not satisfy a design condition which is explained in the body of this article. It means that if a system is observable and has no unstable transmission zeros, the design of a time delayed controller is always possible. The proposed method is also used to control the attitude of a rotor system.