Analysis Of Variable Stiffness Mechanism And Mechanical Characteristics Of A Type Of Micro-nano Probe With Compliant Triangular Beam Constraint

The micro-nano probe is the core component of the micro-nano coordinate measuring machine,and its stiffness characteristics directly affect the overall performance of the measuring machine.Different measuring process and measuring object all require different supporting stiffness of the micro-nano probe.At present,the researches on the micro-nano probe and its supporting mechanism are mainly focused on the fixed stiffness.The study on the micro-nano probe structure with variable supporting stiffness has an important theoretical and practical significance.A new type of variable stiffness micro-nano probe with triangular beam constraint was constructed.Selecting appropriate measuring rod and measuring ball structure,the displacement measurement system was constructed by using the variable distance capacitance sensor to detect the trigger signal of the micro-nano probe.Based on the characteristics of a flexible mechanism,a new type of flexible steering mechanism was constructed.A suitable stacked piezoelectric actuator was introduced and selected to drive the new compliant steering mechanism.The numerical relationship between the axial pressure of the constrained beam and the piezoelectric was obtained.The modal frequency,the allowable stress and the fatigue failure of the new compliant steering mechanism was simulated and analyzed by employing the finite element analysis.The theoretical stiffness model of the constrained supporting mechanism was established by using the principle of minimum potential energy.Based on the theoretical model,the axial pressure required when the constrained supporting mechanism reaches the isotropic stiffness and the critical buckling load when the constrained beam fails were obtained.Given the dimension parameters of the constrained supporting mechanism,the stiffess curve of the constrained beam with the axial pressure was obtained by employing the finite element simulation tool.Comparing the theoretical and simulated values of the supporting stiffness,the results show that the established theoretical stifffness model is correct.The optimal size parameters of the constrained supporting mechanism were selected by using the orthogonal test method to reduce the isotropic stiffness of the constrained supporting mechanism.The dynamic characteristics such as the modal,the harmonic response and transient response when the stiffness of the constrained supporting mechanism reaches isotropic are simulated and analyzed.Figure 41 table 7 reference 80...