关键词: 柔顺位移放大机构, 运动学综合, 中点漂移, 蒙特卡洛方法, 全局敏感性分析

Abstract: Designing Displacement Amplification Mechanism (DAM) is one of the common strategies to enlarge the output displacement of piezoelectric stack actuator and further enlarge the workspace of precision positioning stage and micro-nano-manipulator.For compliant DAMs,how to enlarge the displacement amplification ratio and make the output displacement achieve the expected direction is a keypoint.In this paper,a compliant orthogonal two-stage leverage DAM was designed systematically and analyzed.The demands of kinematic properties for the mechanism and piezoelectric stack actuator were analyzed,and the systematic structural design of compliant orthogonal two-stage leverage DAM was conducted by combining the analysis of freedom degree and rigid body substitution.With the consideration of midpoint drift of the flexure hinges as well as the deformation of beam,the displacement amplification ratio of DAM was modeled statically by using vector polygon,Castigliano's second theorem as well the equations of static equilibrium.Further,based on Monte-Carlo method,the global sensitivity analysis of dimensional parameters in the DAM was conducted.The kinematic synthesis of DAM,the modeling of displacement amplification ratio as well as the sensitivity analysis results were verified by finite element simulation.Based on the results of sensitivity analysis and finite element simulation,the fabrication tolerance of dimensions for the DAM was further designed.The result showed that the proposed displacement amplification ratio modeling and sensitivity analysis method needed not use the condition that the output displacement was orthogonal to the input displacement,which could be applied to the general compliant multi-stage leverage DAM.

Key words: compliant displacement amplification mechanism, kinematic synthesis, midpoint drift, Monte Carlo method, global sensitivity analysis