An approximation technique to tune PID controllers

Advanced controller synthesis techniques often result in high order controllers whose order exceeds the order of the plant and it is impractical to implement. The main use of the advanced synthesis techniques is to find the possible optimal performance of the system and thus to check how a practical simpler controller comes close to achieving that optimum. PID controllers are the most found in industry and here we describe a novel technique, based on approximation, to tune the parameters of PID controllers.