A SYNTHESIS THEORY FOR A CLASS OF UNCERTAIN LTI SYSTEMS WITH AMPLITUDE AND RATE SATURATION

This paper is devoted to extend the synthesis theory developed in a previous work, to guarantee prescribed performance of a feedback system with an uncertain linear plant with one integrator and with rate and amplitude saturating elements. Using a three degrees of freedom scheme a design method is proposed, within the framework of Quantitative Feedback Theory (QFT), that extends the existing synthesis theory to take the plant uncertainty into account when this type of non-linear elements are present. The major factor in this method is Ln, the system loop transmission with respect to the saturating elements. It is shown how the compensator [F, G, H] can be synthesized to achieve desired performance even under hard saturation using a new type of specifications over a function of Ln. The proposed method is illustrated using an example to emphasize the practical application of the resulting technique.