Robust self tuner for variable time delay systems

Abstract

A robust self tuner is presented for systems with unknown or variable time delay systems. A stability protection function is included in the controller to safeguard against instability caused by changes in the time delay of the process. Based on the behaviour of the self tuner in variable time delay systems, a simple time delay tracking technique is used to track the estimated process time delay parameter d0 every r sampling periods. Robustness of the proposed self tuner is achieved by combining the above two techniques. A simulation example will be presented to illustrate the proposed self tuner.