关键词: 柔性铰链, 矢量闭环, 微动工作台, 误差源, 运动学

Abstract: The parallel micro-motion platform is widely used in high-precision situation. Considering that the manufacturing error, assembly error, and temperature and gravity effect will have negative influence on the positioning accuracy of platform, it is necessary to discuss the error sources. A micro-motion platform with 3-PPTTRS mechanism, is taken as an example, an arm link-based error model and a flexure hinge-based error model are established on the basis of the nominal model of one sub-chain according to vector closed loop theory. The manufacturing error of arm-link, manufacturing and assembly errors of flexure hinge, actuator motion error and temperature effect on arm-link length are considered, and corresponding vector closed loop function is established. The effects of manufacturing and assembly errors of flexure rotational hinge, flexure spherical hinge and flexure hooke hinge on the terminal positioning accuracy of micro-motion platform are analyzed respectively. The effects of manufacturing errors of flexure hinge, such as the error of incising radius, displacement deviation of incising circle center along x or y axis, and deflection along z axis, and assembly errors in axiality and verticality of flexure hinge on the terminal pose of micro-motion platform are analyzed in detail. And so are the effects of temperature and gravity on the accuracy. Finite element simulation result indicates that temperature has great effect on the positioning accuracy while gravity effect is small and can be ignored. This method provides an effective route for the accuracy design of complex parallel micro-motion robots.

Key words: Error sources, Flexure hinge, Kinematics, Micro-motion platform, Vector closed loop