Method of mechanism synthesis by hybrid genetic algorithm

Abstract

The path synthesis problem for mechanical linkages still presents problems for engineers, although it has been examined for more than two centuries. This research approached the design problem as one of creating a characteristic test function to compare a synthesized output path with a desired output path, and reducing the corresponding error. Since the solution space corresponding to the linkage design problem is very large with typically a generous number of local minima, a modified genetic algorithm was utilized to search for the global minima. A benefit of the genetic algorithm method is that in this search for the global minima it will also locate a family of alternative solutions that possess near optimal outputs. Having these alternative solutions allows mechanism designers to choose the mechanism that best fits the particular physical constraints of the system they are designing. The genetic algorithm was tailored to a particular mechanism problem by the choice of crossover and mutation methods used, along with the implementation of a local search improvement operator. The results from using this method on a subclass of linkage problems were compared with the current accepted solutions to evaluate tee effectiveness of approaching mechanism design in this fashion. In particular the ability of the genetic algorithm to identify known designs as well as new mechanisms was demonstrated.