基于复合优化方法立式数控加工中心的多目标优化设计

Multi-objective optimization design for a vertical machining center based on composite optimization method

为实现加工中心动静态性能不低于优化前性能,达到整机重量最轻的要求,提出了一种复合优化方法来研究多变量、多约束和多目标的数控加工中心优化设计。采用有限元分析和实验模态测试方法分析各大件动态性能,并验证了有限元模型的精确性。然后以该有限元模型为基础进行静态分析,得出各大件的最大变形及应力等。以柔度为目标,采用变密度法拓扑优化设计立柱结构的外形框架;以固有频率为目标,基于元结构的可适应性动态优化方法设计加工中心的筋板结构;以固有频率和质量为目标,基于响应面法的尺寸优化确定各结构的最优尺寸。最后将优化后的各大件进行整机装配,分析校核整机动静态性能。结果表明,优化后的整机在保证加工中心动静态性能的条件下,整机质量从12 749 kg减少到12 127 kg,减重达到4.9%,达到了整机的优化设计要求,说明该方法具有较高的精度和较强的工程实用性。

In order to satisfy the dynamic and static performance requirement of a machining center and minimize its weight,a composite optimization method was proposed to study design of a machining center with multi-variable,multi-constraint and multi-objective.By combining finite element analysis with modal test,the dynamic behavior of each big part of the center was analyzed to verify the correctness of the finite element model.Then,their maximum deformation and stress were obtained with a static analysis based on the finite element model.Taking compliance as a goal,topologic optimization was adopted to design the framework shape of column structures;taking natural frequency as a goal,adaptive dynamic optimization method based on a unit structure was used to design rib structures of the machining center;taking mass and natural frequency as goals,response surface methodology was used to determine the optimal size of the structure of each part.Finally,the dynamic and static performance of the whole center was analyzed after all optimized parts of the machining center were assembled.The analysis results showed that the weight of the maching center is reduced about 4.9%,from 12749kg to 12127kg,the proposed method has higher precision and stronger practicability.