【摘要】 微纳测头是精密测量机的关键部件,其刚度特性直接影响坐标测量机的整体性能。基于压杆失稳原理,构造一种具有变刚度特性的新型微纳测头。利用压电装置驱动柔性机构变形以改变柔性支撑梁的轴向受力和横向刚度,从而改变约束支撑机构的整体刚度。综合考虑测头的刚度特性、结构稳定性和解耦性等因素,构造出基于十字交叉型悬臂梁支撑的变刚度微纳测头。利用最小势能原理构建微纳测头约束支撑机构的刚度模型,基于模型获得所需压电驱动力大小。通过有限元仿真得到测头刚度随压电驱动力变化的曲线。对比刚度理论计算值与仿真值,分别得到微纳测头约束支撑机构的轴向刚度及横向刚度的平均相对误差。仿真结果表明,建立的刚度理论模型具有较高的准确性。研究结果为该新型微纳测头的变刚度控制奠定了理论基础。更多还原

【Abstract】 The micro-nano probe is a key component of precision measuring machines.Its stiffness characteristics directly affect the overall performance of the coordinate measuring machine.Based on the principle of pressure rod instability,a novel micro-nano probe with variable stiffness characteristics was constructed.The piezoelectric device was used to drive the deformation of the flexible mechanism to change the axial force and lateral stiffness of the flexible support beam,and then the overall stiffness of the constrained supporting mechanism was varied.Considering the stiffness characteristics of the micro-nano probe,the structural stability and the decoupling,the variable stiffness probe based on the cross-cantilever beam support was established.The principle of minimum potential energy was used to derive the stiffness model of the constrained supportingmechanism of the micro-nano probe.Based on the above model the required piezoelectric drive force was obtained.The stiffness curve of the probe with respect to the piezoelectric driving force was described by employing the finite element simulation.Comparing stiffness theory calculated values and simulated values,the average relative error of the axial stiffness and lateral stiffness of the constrained supporting mechanism of the micro-nano probe were obtained.The simulation results showed that the established stiffness model had high accuracy.The result of the study laid a preliminary theoretical basis for the variable stiffness control of the novel micro-nano probe.更多还原