Designing robust mixed H2/H∞ PID controllers based Intelligent Genetic Algorithm

It´s not easy to implement the mixed H₂/H_∞ optimal controller for high order system, since in the conventional mixed H₂/H_∞ optimal feedback the order of the controller is much than that of the plant. This difficulty had been solved by using the structured specified PID controller. The merit of PID controllers comes from its simple structure, and can meet the industry processes. Also it has some kind of robustness. Even that it´s hard to PID to cope the complex control problems such as the uncertainty and the disturbance effects. The present idea suggests combining some of model control theories with the PID controller to achieve the complicated control problems. One of these ideas is presented in this paper by tuning the PID parameters to achieve the mixed H₂/H_∞ optimal performance by using Intelligent Genetic Algorithm (IGA). A simple modification is added to IGA in this paper to speed up the optimization search process. Two MIMO examples are used during investigation in this paper. Each one of them has different control problem.