A case study on the selection of performance index for design optimization of new controllers

Designs are typically judged subjectively rather than by analytical techniques in which the engineer is trained. To alleviate this problem, the concept of the merit index is introduced to quantify the way in which new designs are measured. This analytical technique is used in selecting the optimal design. The merit index is a unit measure that is a function of the design adequacy, producibility, compatibility, reliability, and cost effectiveness. The design objectives are expressed as indexes and assigned individual weights to represent the relative importance in the performance index. A design methodology is provided to simplify the design process by utilizing analytical rather than subjective approaches to the optimization of product development. The development of a variable reluctance servomotor controller is used as a case study to illustrate the technique