A novel evolutionary engineering design approach for mixed-domain systems

This paper presents an approach to engineering design of mixed-domain dynamic systems. The approach aims at system-level design and has two key features: first, it generates engineering designs that satisfy predefined specifications in an automatic manner; second, it can design systems belonging to different or mixed physical domains, such as electrical, mechanical, hydraulic, pneumatic, thermal systems and/or a mixture of them. Two important tools are used in this approach, namely, bond graphs and genetic programming. Bond graphs are useful because they are domain independent, amenable to free structural composition, and are efficient for classification and analysis, allowing rapid determination of various types of acceptability or feasibility of candidate designs. Genetic programming, on the other hand, is a powerful tool for open-ended topological search. To prevent the premature convergence often encountered in evolutionary computation, a hierarchical fair competition model is adopted in this work. Examples of an analog filter design and an MEM filter design illustrate the application of the approach.