机床中结合部分布众多且不同接触条件下其动刚度值不同，优化分析时很难研究每个动刚度值对机床动态性能的影响。针对此类问题，提出一种基于正交试验的机床结合部动刚度优化配置方法。该方法通过模态柔度与弹性能分布理论判定机床的薄弱模态和薄弱结合部，建立以薄弱结合部的动刚度为设计变量，各阶薄弱模态的最小模态柔度为目标的多目标优化模型。为提高优化效率，采用正交试验方法规划试验方案，并在试验结果分析中引入相似优先比法对结合部动刚度进行协同优化配置。以某型立式加工中心为例，采用优化配置方法确定其结合部动刚度的最优配置方案。仿真结果显示该方案下薄弱模态的模态柔度明显降低，整机动态性能提高，验证了该方法的可行性。

There are many joints in the machine tool and each joint has different dynamic stiffness under different contact conditions, when conduct the optimization it is difficult to study how each dynamic stiffness affects the dynamic characteristics of machine tool. To solve the problem, an optimal configuration method of dynamic stiffness of machine tool joints based on orthogonal experiment is proposed. The weak modes and joints are determined based on the modal flexibility and elastic energy distribution theory. Then a multi-objective optimization model is established, in which dynamic stiffness of each weak joint is regarded as the design variable and the minimum modal flexibility of each weak mode is regarded as the objective. An orthogonal experiment method is adopted to improve the optimization efficiency, and theory of similarity priority ratio is introduced in the results analysis to conduct the collaborative optimal configuration of the joints dynamic stiffness. The optimal configuration method is applied in a vertical machine center. The simulation shows that the modal flexibility of each weak mode is decreased obviously after the optimization, and then the dynamic characteristic of the whole machine tool is improved. Thus this optimal configuration method is verified to be feasible.