Low order robust controller design for preserving H∞ performance: Genetic algorithm approach

This paper investigates the design of low order robust controllers based on an H∞ performance index using a real-code genetic algorithm. In H∞ controller design, the major disadvantage of the existing methods is that they lead to high-order controllers. This is the gap between theory and practice. Therefore the purpose of this paper is to design a low order controller with similar performance to the H∞ optimal controllers, which can find sufficiently wide use in engineering practice. We first design the H∞ optimal controller using Glover and Doyleʹs results, and obtain the corresponding performance index γ Second, the desired low order controller with several parameters is chosen, e.g., a first-order controller, or a PID controller. Finally, we use the real-code genetic algorithm to find the optimal controller parameters that preserve the performance index γ Computational simulations illustrate the effectiveness of the proposed approach.