A design method of modified PID controllers for multiple-input/multiple-output plants

In this paper, we examine a design method of modified PID (Proportional-IntegralDerivative) controllers for multiple-input/multiple-output plants. PID controller structure is the most widely used one in industrial applications. Recently the parametrization of all stabilizing PID controller has been considered. Yamada and Hagiwara proposed a design method of modified PID controllers such that modified PID controllers make the closed-loop system for single-input/single-output unstable plants stable and the admissible sets of P-parameter, Iparameter and D-parameter are independent from each other. However, no method has been published to guarantee the stability of PID control system for multiple-input/multiple-output plants and the admissible sets of P-parameter, I-parameter and D-parameter to guarantee the stability of PID control system are independent from each other. In this paper, we propose a design method of modified PID controllers such that the modified PID controller make the closed-loop system for multiple-input/multiple-output plants stable and the admissible sets of P-parameter, I-parameter and D-parameter are independent from each other. Copyright c ©2008 IFAC