基于交叉簧片柔性铰链的空间微位移机构

Spatial compliant micro-displacement magnifying mechanism based on cross-spring flexural pivot

基于交叉簧片柔性铰链(简称‘交叉铰链’)设计了一种用于光束跟踪、精密指向和瞄准的同轴八铰微位移放大机构。该机构使用菱形构型,用交叉铰链作集中柔性元件,节点处交叉铰链两两同轴配合使用,以便保证运动的平稳输出。研究了机构的运动学以及力学性能,计算了微位移机构的行程放大比和灵敏度;根据交叉铰链的刚度模型,推导出微位移机构的理论刚度;最后,应用有限元软件对机构进行建模并对运动学、静力学以及动力学性能进行仿真。完成了样机的加工和测试,测试结果显示,机构放大比为1.905,理论与测试误差低于2.2%,结构刚度为18.21N/mm,误差低于0.32%,一阶频率为8.8Hz,误差低于5%。分析结果验证了本设计的可行性和有效性。该机构适用于空间高精度微位移领域。

A new diamond micro-displacement magnifying mechanism using eight cross-spring flexural pivots was presented for light beam acquisition,tracking and pointing in space optical communication.The piezoelectric ceramic was taken as the actuator,and the cross-spring flexural pivots as the centralized flexural elements.Every two pivots were set in one axis,and the coaxial set of two pivots on each corner of the diamond configure could reduce the axis draft and improve the rigidity and stability of the mechanism.Through analyzing the operation principle,the magnifying ratio and the sensitivity of the mechanism were derived.According to the stiffness model of the cross pivots,the theoretical stiffness of the displacement mechanism was deduced.Finally the displacement mechanismwas modeled by finite element method and its kinematics,statics and dynamics were simulated.A prototype was established and tested.Some characteristic parameters were derived,such as the structure stiffness and the eigen frequency of the mechanism.The test results show that the magnifying ratio is 1.905 with the error of 2.2%,the stiffness is 18.21N/mm with the error of 0.2%and the eigen frequencies is 8.8Hz with the error of 5%.The experimental data verify the feasibility and effectiveness of proposed design and show that the mechanism is suitable for high precise spatial micro-displacement fields.