3 SPS+SP并联机构的静刚度分析

少自由度并联机构中存在约束反力,该力会使机构产生变形。以3-SPS+SP并联机构为例,建立了同时含有驱动和约束的全雅可比矩阵。考虑结构模型中约束反力对机构的影响,采用能量等效原理推导了输入驱动力及约束反力与外负载的映射关系,建立了该机构的全刚度模型,得到了机构的动平台线性平移及角度旋转变形量与外负载的关系。定义了该机构的刚度评价指标,分析了主要结构参数与全局刚度评价指标的变化规律,为该机构的结构参数优化奠定了基础。

Static Stiffness Analysis of Parallel Mechanism 3 SPS+SP

The constraint reaction is existed in a patallel mechanism with fewer degrees of freedom ( DOF) , which leads to its de-formation.The whole Jacobian matrix containing drive and constraint was set up by 3-SPS+SP parallel mechanism .By considering the structure model of constraint reaction influence on the mechanism , the mapping relationship between input driving force and binding re-action and external load was derived .The whole of stiffness model was established , and the relationship between moving platform linear translation and angle rotation deformation with the external load was obtained .The stiffness evaluation indexes were defined .The chan-ging rule between main structural parameters and the global stiffness evaluation index are analyzed , which laid the groundwork for the structural parameters of mechanic optimization .