Design And Characteristics Analysis Of A Piezoelectric-Actuated Micro/Nano Positioning Stage

With the development of micro/nano technology,the positioning technology based on traditional mechanical transmission has been difficult to meet the strict requirements of positioning accuracy in micro/nano technology fields such as micro-nanomanipulation,micro-nanometrology and micro-nano manufacturing technology.Thus,there is an urgent need for a positioning system with micro/nanometer positioning accuracy and large stroke and high dynamic response.Piezoelectric-actuated micro/nano positioning system driven by piezoelectric actuator and guided by complainant mechanisms,which has high motion accuracy and fast response,and has become a hot research area in precision and ultraprecision positioning technology field.Thus,research on the piezoelectric-actuated micro/nano positioning systems with the advantages of large-stroke and high-precision has important scientific significance for promoting the development of precision,ultraprecision positioning technology and nanotechnology in our country.This study is based on open projects from Shanghai Key Laboratory of Spacecraft Mechanism.The working principle,static and dynamic characteristic,cross-axis coupling characteristic,finite element simulation analysis,static and dynamic testing and structural optimization design for piezoelectric-actuated micro/nano positioning systems have carried out.The main research contents are summarized as follows:(1)The working principle and performance of the compliant mechanisms of largestroke micro/nano positioning systems have studied.The working principle and components of large-stroke micro/nano positioning systems were discussed.The inherent characteristics of piezoelectric actuators was studied.The working performance of flexible hinges and compliant displacement amplification mechanisms were compared and analyzed.(2)The static and dynamic characteristics of large-stroke micro/nano positioning systems have studied.Based on the pseudo-rigid body model method,the Castigliano's second theorem and the elastic beam theory,the analytical models of displacement amplification ratio,input/output stiffness of bridge-type displacement amplification mechanisms were established,which reveal the influence of the geometrical parameters of bridge-type mechanisms on its motion performance.By considering the influence of structural stiffness of compliant positioning stages on the output displacement of piezoelectric actuators and displacement amplification mechanisms,the kinematics and output displacement attenuated models of piezoelectric-actuated positioning system were derived,and the deformation coordination of large-stroke micro/nano positioning systems is studied.By considering parasitic motion of the compliant positioning stage,the crossaxis coupling error model of the compliant positioning stage was established,which reveals the cross-axis coupling characteristics of the large stroke positioning system.Based on the pseudo-rigid body model method,the lumped mass method and the Lagrange motion differential equation,the natural frequency analytical model of bridgetype displacement amplification mechanisms and compliant positioning stages were established,and the dynamic characteristics such as the natural frequency of the bridgetype mechanism and compliant positioning stage were obtained.(3)The static and dynamic testing and performance evaluation methods for large stroke micro/nano positioning systems have studied.Based on the integrated processing prototype of a 6-DOF compliant positioning stage,the linearity and repeat positioning accuracy evaluation methods of micro/nano positioning systems were established.The static and dynamic testing platform of the micro/nano positioning system were set up to verify the reliability of the established kinematics and displacement attenuation model and the natural frequency analytical model.In addition,the Static and dynamic performance indicators such as hysteresis characteristics,open/closed linearity,repeated positioning accuracy and displacement resolution of the positioning system were tested.(4)The optimization design method of a large stroke micro/nano positioning stage has studied.Based on the deformation coordination principle of piezoelectric-actuated positioning systems,the design methods of a compliant positioning stage with large stroke and high dynamic response was discussed.Based on bridge-type and lever mechanisms,a multi-stage displacement amplification mechanism was proposed,and a novel 2-DOF micro/nano positioning stage was designed.Combined with the established static and dynamic analytical models,a multi-objective optimizing model of compliant stages was constructed.The static and dynamic performance of the presented 2-DOF positioning stage was optimized,and the optimized compliant positioning stage enables large working range while maintaining an ideal dynamic frequency.