Design of Fixed Order H∞ Controllers with Specified Settling Time using D-Decomposition

Abstract

The H∞ control theory has the high level. But application in industry, owing the complexity of theory, is limited. Controller design is based on complex numerical procedure (Nevannlina–Pick algorithm) and given parameters does not have physical meaning. Also, the order of the controller is high (at least as an order of system). Owing that facts in this paper we propose simple interactive procedure for H∞ PI controller design. The procedure is simple and is based on D-decomposition. In comparison with original H∞ controller here we introduce constraint in the form of specification of settling time. The program for procedure of H∞ PI controller design is simple and based on MATLAB (Robust Control Tool Box). Given PI controller is applied for control of CSTR (continuous stirred–tank reactor). The process is described as linear model with time delay. In this paper the time-delay approximated with second order Pade approximation. Finally, designed controller provides nominal performance for control systems.