A decision support system for multi-objective 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, the authors 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. Computer-aided design within a framework of multi-objective programming is seen as a plausible solution. A decision support system is devised to support such an apparoch and a prototype is implemented in Pro-Matlab as a set of Matlab files. This paper seeks to communicate the present view of practical design, presents the approach and portrays the development of the DSS with a design example to demonstrate its usefulness.