Evolutionary CAutoCSD and its applications

Abstract

This paper attempts to set linear time-invariant control system design to a unified scene by transforming 'Computer-Aided Control System Design' to 'Computer-Automated Control System Design'. The first step towards this goal is to accommodate, under practical constraints, all design objectives that are desirable in both time and frequency-domains. Such performance-prioritised unification is aimed to relieve practising engineers from having to select a particular control scheme and from sacrificing certain performance goals resulting from pre-committing to the adopted scheme. With the recent progress in evolutionary computing based extra-numeric, multi-criterion search and optimisation techniques, such unification of linear time-invariant (LTI) control schemes is feasible, analytically and practically, and the resultant designs can be creative. The techniques developed are applied to, and illustrated by, three design problems. The unified approach automatically provides an integrator for zero-steady state error in velocity control of a DC motor, meets multiple objectives in designing an LTI controller for a non-minimum phase plant and offers a high-performing LTI controller network for a nonlinear chemical process.