MULTIOBJECTIVE OPTIMIZATION AND MULTIPLE CONSTRAINT HANDLING WITH EVOLUTIONARY ALGORITHMS - PART II - APPLICATION EXAMPLE

The evolutionary approach to multiple function optimization formulated in the first part of the paper [1] is applied to the optimization of the low-pressure spool speed governor of a Pegasus gas turbine engine, This study illustrates how a technique such as the multiobjective gen etic algorithm can be applied, and exemplifies how design requirements can be refined as the algorithm runs, Several objective functions and associated goals express design concerns in direct form, i,e,, as the designer would state them, While such a designer-oriented formulation is very attractive, its practical usefulness depends heavily on the a bility to search and optimize cost surfaces in a class much broader th an usual, as already provided to a large extent by the genetic algorit hm (GA), The two instances of the problem studied demonstrate the need for preference articulation in cases where many and highly competing objectives lead to a nondominated set too large for a finite populatio n to sample effectively, It is shown that only a very small portion of the nondominated set is of practical relevance, which further substan tiates the need to supply preference information to the GA, The paper concludes with a discussion of the results.