Fixed structure robust H∞ loop shaping control of feedback linearised CSTR using PSO

Abstract

A fixed-structure polynomial controller based on robust H∞ loop shaping control for feedback linearised CSTR is proposed in this paper. It can be used to guarantee the robust performance under a structure-specified controller. In this proposed technique, the performance and robust stability conditions of the designed system satisfying the H∞ loop shaping are formulated as the objective function in the optimisation problem. Particle swarm optimisation (PSO) is applied to solve this problem and to achieve the control parameters of the proposed controller. Additionally, in the proposed technique, the performance weighting function, which is normally difficult to obtain, is determined by using PSO. The optimal stability margin is used as an objective function in PSO for selecting the optimal weighting parameters. Simulation results of feedback linearised CSTR show that the proposed controller has simpler structure than that of the conventional Η∞ loop shaping controller and its stability margin is near the Η∞ loop shaping controllers.