考虑连杆和关节柔性的工业机器人大臂静动态性能优化

Optimization of Static and Dynamic Performance of Industrial Robot Forearm Considering Flexibility

摘要:

为提高工业机器人整体性能，减小其静动态性能误差，提出一种综合考虑工业机器人连杆和关节柔性的拓扑优化方法。将机器人动力学与拓扑优化相结合，以变密度法(Solid isotropic material with penalization,SIMP)为基础，通过线性加权和法建立工业机器人大臂的多目标拓扑优化函数模型，基于柔性多体动力学理论，利用有限元软件和多体动力学软件建立含关节、连杆柔性的机器人刚柔耦合动力学仿真模型，获得机器人在极限工况下大臂载荷谱，最后，利用层次分析法确定优化目标函数中各子目标的权重系数，并对函数进行求解。优化结果显示，优化后机器人大臂刚度和固有频率都得到提高，并且质量下降18.71%。通过虚拟样机技术重构机器人模型，并对其整体进行分析，结果表明，最大负载作用下，机器人最大变形量从0.208mm降至0.188mm，静态变形量误差减小9.62%；动态定位误差从0.777mm降至0.687mm，定位精度提高11.58%。上述拓扑优化方法为提升工业机器人整体静动态性能提供了有效的理论参考。

关键词:工业机器人;静动态性能;拓扑优化;刚柔耦合动力学;层次分析法;定位精度

Abstract:

With the development of automation technology, industrial robots are widely used in various fields, in order to improve the overall performance of industrial robots and reduce their static and dynamic performance errors, a topology optimization method that integrally took into account the flexibilities of connecting rods and joints of industrial robots was proposed. Combining robot dynamics and topology optimization, the multi-objective topology optimization function model of industrial robot forearm was established by linear weighted sum method based on the solid isotropic material with penalization (SIMP), based on the theory of flexible multi-body dynamics, the simulation model of robot rigid-flexible coupling dynamics with joints flexibilities and connecting rods flexibilities was established by using the finite element software and multi-body dynamics software, and the load spectra of the robot forearm was obtained in the extreme working conditions. Finally, the weight coefficients of each sub-objective in the optimization objective function were determined by using hierarchical analysis and the function was solved. The optimization result showed that the stiffnesses and natural frequencies of the optimized robot forearm were improved, the robot forearm was lightened by 18.71% from 20.233kg to 16.477kg. The robot model was reconstructed by virtual prototype technology and its whole was analyzed, and the result showed that the maximum deformation displacement of the robot was decreased from 0.208mm to 0.188mm under the maximum load, and the static deformation error was reduced by 9.62%, the dynamic localization error was decreased from 0.777mm to 0.687mm, and the localization accuracy was improved by 11.58%. The above topology optimization method provided an effective theoretical reference for improving the overall static-dynamic performance of industrial robots.

Key words:industrial robot;static and dynamic performance;topology optimization;rigid-flexible coupling dynamics;hierarchical analysis;positioning accuracy