3DOF并联加载机构静力学和静刚度分析

基于螺旋理论建立了用于数控机床随动加载的3自由度并联机构的静力学方程，得到机构的驱动力与动平台所受外载的映射关系，方程考虑了支链重力对静力学模型的影响，通过算例绘制了在指定载荷下机构驱动力在工作空间内的分布曲线图.在考虑支链重力和在约束力下支链弹性变形对刚度影响的情况下，建立了机构的静刚度模型，分析了给定静载荷条件下机构在定姿态空间内的变形分布情况，并评价了机构的刚度性能，结果表明机构的刚度特性关于y轴对称且在工作空间的边界刚度变差.

Statics and stiffness of 3 DOF parallel loading mechanism

A static model of a 3-DOF parallel mechanism (PM) that is used for computerized numerical control (CNC) machine tool follow-up loading test was established based on the screw theory. The mapping between actuation force and loading force of the moving platform was built considering the influence of limbs' weight. Then the distribution of actuation forces in workspace under specified loads was analyzed through a numerical example. Moreover, the static stiffness mapping model of the PM was established. The model considers influences of the limbs' weight and the parts' elastic deformation under the constraint force. At last the deformation of the PM in the workspace under given static loads was analyzed and the stiffness characteristic was evaluated. The results show that the distribution of stiffness in workspace is symmetrical about the y-axis and the stiffness will be worsened when it comes near the workspace boundary.