采用多目标进化算法对正铲挖掘机工作装置进行优化设计，目标是水平直线挖掘铲斗切削后角变化量、主要挖掘区域内纵向斗杆挖掘最大挖掘力和纵向铲斗挖掘最大挖掘力3个性能指标。针对NSGA-II处理具有复杂Pareto最优前端优化问题能力不足的问题，提出动态拥挤排序策略，提高算法求解的多样性，引入差分算子和柯西变异算子，提高算法的全局寻优能力。使用ZDT系列测试函数对改进算法进行测试研究，结果表明改进算法的收敛性指标和多样性指标均有很大提高，能够很好地处理具有复杂Pareto最优前端的优化问题。基于改进的优化算法对正铲挖掘机工作装置进行优化设计，并利用理想解法得到了最满意优化方案，优化结果表明了改进算法应用于实际工程问题的有效性和可行性。

A multi-objective evolutionary algorithm is applied to optimize the face-shovel excavator attachment, which sets the variable quantity of bucket’s cutting angle in excavating along horizontal line, the stick digging force and the bucket digging force in vertical direction in main digging range as optimization goals. Aiming at improving the performance of NSGA-II in the optimization problems of complicated Pareto front, a dynamic sorting algorithm is designed to improve the diversity. Differential evolution operator and Cauchy mutation operator are proposed for improving the convergency and the ability of global optimization. By using a class of continuous multi-objective optimization test instances to test the improved NSGA-II, the experimental results indicate that the proposed algorithm could significantly outperform NSGA-II on these test instances. The proposed algorithm is applied to a practical example of face-shovel excavator, and can make use of TOPSIS to select the most satisfied schedule from the Pareto set. The comparison with other schemes testifies the feasibility and effectiveness of the improved NSGA-II.