空间机械臂在轨刚度计算与验证

Calculation and Verification of On-orbit Stiffness of Space Manipulator

空间机械臂在执行空间任务时具有不同的构型,采用有限元法分析它在各构型下的基频时工作量巨大而难以实现。为此,提出一种基于柔度矩阵理论建模的计算方法并进行验证。根据机械臂结构特性建立运动学模型;提出柔度矩阵理论建模的计算方法;通过有限元仿真分析机械臂2种典型构型,验证柔度矩阵理论;对机械臂进行地面展开基频实验。结果表明:柔度矩阵计算偏差为3.4%,理论分析基频与有限元计算基频偏差为1%,验证了所提出的柔度理论建模方法对机械臂在轨基频计算的准确性;理论分析基频与实验基频偏差为7.2%,偏差主要来源于有限元仿真,满足工程上10%的偏差要求。该方法将柔度矩阵与机械臂构型相结合,能快速计算机械臂在不同构型下的基频。相对于有限元法,该方法得到较大简化,具有一定的工程应用价值。

Space manipulator has different configurations when performing space tasks,so it is difficult to realize the fundamental frequency of space manipulator under different configurations by using finite element analysis.Therefore,a calculation method based on flexibility matrix theory modeling was proposed and verified.The kinematics model was established according to the structural characteristics of the manipulator;the calculation method of the flexibility matrix theoretical modeling was proposed;the flexibility matrix theory was verified through the finite element analysis of the manipulator under two typical configurations;the ground-based fundamental frequency experiment for the manipulator was verified.The results show that the flexibility matrix calculation deviation is 3.4%,and the deviation between the theoretical analysis fundamental frequency and the finite element calculation fundamental frequency is1%,indicating that the flexibility theoretical modeling method proposed is accurate to the fundamental frequency calculation of the mechanical arm in orbit;the deviation between the theoretical analysis fundamental frequency and the experimental fundamental frequency is 7.2%,the deviation mainly comes from the finite element simulation,which meets the engineering requirement of 10%deviation range.In this method,the flexibility matrix is combined with the manipulator configuration,the fundamental frequency of the manipulator in different configurations can be calculated quickly.Compared with the finite element method,the proposed method is greatly simplified and has some engineering application value.