Genetic Design of Robust PID Controllers

Genetic algorithms are proposed as a new and novel technique to solve the problem of designing a robust PID controller for a plant with model uncertainties. The evolutionary scheme used, involves generating two separate populations, one representing the controller and the other the plant. The controller population is then co-evolved against a fixed population of plants covering the plant uncertainty search space, such that the controller can control all the plants effectively. A time domain cost function subjected to a frequency domain vector margin stability constraint, is then deployed in order to obtain a robust controller design. This evolutionary approach is illustrated by evolving a PID controller for a linear plant which has a set of prescribed model uncertainties.