On the design of multivariable PID controllers via LMI approach

We study the design problem of multivariable PID controllers which guarantee the stability of the closed loop systems, H/sub 2/ or H/sub /spl infin// performance specifications, or maximum output control requirement, respectively. The basic idea of our method is to transform the problem of PID controller design to that of static output feedback controller design. Algorithms based on an iterative linear matrix inequality technique are developed to find the feedback gains of PID controllers corresponding to the above mentioned four cases.