Research On Technology Of Large-travel And High-load Precision Translation Stage Based On Piezoelectric Actuator

With the development of manufacturing technology,ultra-precision machining,precision instruments,semiconductor manufacturing,biomedical engineering and many other fields,precision positioning technology based on piezoelectric ceramics has been widely used in industrial production,weapon equipment and scientific research,which is one of the most important technologies to support the development of equipment to high accuracy,high efficiency and intelligence.However,the limited travel and force limitation of the piezoelectric actuator have become the main bottleneck which restricting application of piezoelectric actuator.In order to expand the displacement travel of the piezoelectric actuator and improve stress condition,a double bridge-type displacement amplifier with high symmetry was designed according to the actual engineering demand in this paper,and based on this,a large-travel and high-load precision translation stage based on piezoelectric actuator was developed for the positioning of large-diameter optical elements in optical surface detection system.The research focuses on the output characteristics of piezoelectric actuators,and structural design,theoretical modeling,finite element simulation,performance testing of displacement amplifier and positioning platform.The main research work is as follows:(1)The research background and significance of precision positioning platform has been introduced,the research status of vertical-axis positioning platforms and displacement amplifiers at home and abroad has been deeply investigated.The displacement characteristic of the stacked piezoelectric actuators was tested,and the relationship between the PZT's input voltage and output displacement was studied.(2)In this paper,two types of amplifier with different structures were designed based on the bridge-type mechanism.double bridge-type mechanism,the static model mechanics analysis method based on the Schotborgh's flexible hinge stiffness model and the stiffness matrix method were used to establish the static model of the double bridge mechanism and the combined amplifier respectively.On the base of Lagrange dynamics model,the kinematics model of two types mechanism were established.According to the analysis and comparison,the double bridge-type amplifier with better performance and convenient installation was selected as the final design of the amplifier.The influence of dimensional parameters on mechanism performance has been studied.The size of the mechanism was determined and the finite element simulation software was used to simulate the static and dynamic models of amplifier.The results shows that the theoretical amplification ratio of the amplifier was 11.68,and the first-order natural frequency was 238.64 Hz,the errors with the finite element calculation values of 10.56 and 222.62 Hz were 9.6% and 6.71%,which verified the feasibility of the design.(3)The overall structure of the platform has been determined according to the technical indicators of precision translation stage.The maximum stress model calibration of the platform was checked,and the static stiffness model of the platform was studied.Through the Lagrange equation,the analytical formula of the natural frequency of the platform was derived,and the lightweight design was used to optimize the structure of the platform in order to increase its natural frequency which can improve the anti-interference ability of the platform.After finite element analysis,the natural frequency of the platform was increased from 77.02 Hz to 98.08 Hz.(4)An experimental test system was built to test the performance of the double bridge-type amplifier,such as stroke and bearing capacity.The results shows that the maximum output displacement of the amplifier exceeded 320?m,the displacement magnification ratio was 9,and the load capacity reached 3kg.According to the platform structure design,prototype of precision translation stage was developed,and the platform's output characteristics,load capacity,natural frequency,response speed and other important properties were verified through experiments.The results shows that the platform has a large-travel range of 284.75?m,the load capacity reached 5kg,the natural frequency reached 80 Hz with no-load,and the response speed was less than 5ms,which shows good dynamic performance,the design of platform satisfies the use requirement.