Aiming at the complexity of parallel mechanism structure optimization design,a multi-objective optimization model was proposed and solved by multi-objective differential evolution algorithm.First,a multi-objective differential evolution (MODE) algorithm was proposed.In MODE,an improved quick sort algorithm was employed to build external population, and the shrink of external population was achieved based on dynamic crowding distance, and stochastic ranking was used for constraints.Then, a multi-objective optimization model for 3-TPT parallel mechanism structure was presented.The model’s objectives were the mechanism’s work space and global kinematics performance index which were evaluated by Monte-Carlo method, and the model was solved by MODE.The result shows that MODE is a useful algorithm for multi-objective problems and the multi-objective optimization model is suitable for other parallel mechanisms.

differential evolution, parallel mechanism, multi-objective optimization, Monte-Carlo method