基于有限元3-RPS并联机床轻量化优化设计

为了减轻3-RPS并联机床质量,提高其刚度,分别对静平台与支链进行了结构改进.采用连接单元模拟机床中运动副,对并联机床静刚度进行有限元分析.通过分析结果获得静平台的刚度薄弱环节、支链的变形及其对机床变形的影响规律.在静平台刚度薄弱处增加抵抗变形的筋板,并通过减小其框架尺寸的方式优化静平台结构.采用悬臂梁模型分析支链的变形,以支链质量和变形乘积最小对支链进行尺寸优化.改进后的并联机床质量显著减轻,机床变形明显减小.优化结果能够提高机床动态响应性能以及机床精度.

Lightweight and optimal design for 3-RPS parallel kinematic machine based on finite element method

The structure of the base platform and the links were optimized in order to reduce the mass and increase the stiffness of the 3-RPS parallel kinematic machine(PKM). The static stiffness of the PKM was analyzed with finite element method, using connector in the simulation of kinematic pair. From the analysis, the parts of base platform with low stiffness were identified; the deformations of the links and how they affected the deformation of the PKM were obtained. Ribs largely resisting the deformation were added, and the frame size was reduced to optimize the base platform. Deformation of the link was calculated by using cantilever model, and the dimensions of the link were optimized by minimizing the product of mass and the deformation. After the optimization, the mass and deformation of PKM were significantly reduced. The result can greatly improve the dynamic response and accuracy of the PKM.