A DECISION SUPPORT SYSTEM FOR MULTIOBJECTIVE DESIGN OF PRACTICAL CONTROLLERS

The difficulties present in designing practical controllers are more than just control-theoretic ones, e.g. the presence of right half plane zeros, control costs etc. In this paper, we identify the multi-objective nature and the presence of application-oriented objectives (which are in general non-control-theoretic, e.g. equipment costs, implementability) as two attributes of such practical designs which make them difficult. The first attribute necessitates trade-off decisions (indeed, one view of design is that it is a series of trade-offs). The second complicates the issue by requiring trade-offs between objectives of very different nature at times. We see computer-aided design within a framework of multi-objective programming as a plausible solution. A decision support system is devised to support such an approach and a prototype is implemented in Pro-Matlab as a set of Matlab files. This paper seeks to communicate our view of practical design, presents our approach and portrays the development of the DSS with a design example to demonstrate its usefulness.