Abstract: Particle swarm optimization(PSO) is used to study the dimensional synthesis and optimal type selection of planar mechanisms. A nested PSO method is proposed, which can search the dimension parameters with main PSO and search the pose parameters with sub PSO. The method is applied to the study of path generation problem by building the dimensional synthesis model and optimal type selection model with the nested PSO algorithm. The validity and universality of the method are verified by two case studies, which are dimensional synthesis of planar four bar linkages and optimal type selection of planar multi-bar mechanisms. The main advantage of this method lies on the capability to produce multiple optimized solutions, which provides broader selection for the designer. With nested PSO method, the problem of dimensional synthesis, pose optimization and optimal type selection of planar mechanisms can be solved in a unified approach.

Key words: Dimensional synthesis, Parameter optimization, Particle swarm optimization, Planar mechanisms