Robust PID controller design using particle swarm optimizer

A simple but feasible Robust PID (RPID) tuning methodology is proposed in this paper. Most robust controllers that have been developed in literature by now have complex structures. They are either hard to be implemented or easily broken down. The simplest controller, PID, is chosen to be the prototype of robust controller. Through parameter selection, robust performance is achieved. Minimax criterion guarantees a set of controller parameters to be most optimal to the worst operating condition that may occur within the uncertainty ranges of model parameters. To execute the minimax search, a co-evolutionary algorithm based on Particle Swarm Optimization is advanced. Simulations are presented to demonstrate the advantages of RPID compared with other PIDs.