Uncertainty, Stability and Robustness of Time-Delay Systems

Time delay generally represents the transport delay in a real process. It may deteriorate significantly the properties (stability and transient performance) of a closed-loop control process. But uncertainty in the knowledge of the time delay may cause instability and influences the robustness of the control. Control algorithms are generally very sensitive to delay mismatch. In this paper the robust design of the YOULA parameterized controller is investigated considering delay mismatch. Stability region is given providing design method to ensure stability and the required performance.