Design Of Two Degrees Of Freedom Decoupled Micro-nano Positioning Stage With Large Workspace

With the rapid development of science and technology,micro-nano positioning technology is widely used in many fields such as microelectronic engineering,biological engineering,precision and ultra-precision machining technology,and precision optical engineering,the performance requirements of positioning systems in various fields are increasingly high.The positioning stage driven by piezoelectric ceramics has been widely used due to its advantages of high positioning accuracy and fast response speed.However,there are some disadvantages such as small output displacement of piezoelectric ceramics driver,coupling motion of positioning stage and parasitic motion reducing positioning accuracy;In addition,in order to achieve the optimal performance of the positioning stage,optimization algorithm is usually used to obtain optimal solutions based on the positioning stage model,the accuracy of the model is crucial to the reliability of the optimal solutions,the existing modeling methods have some disadvantages,such as poor modeling accuracy or complex models and poor generality.Based on this,a new two-degree-of-freedom decoupled large-stroke micro-nano positioning stage driven by piezoelectric ceramics is designed,and a modeling method to improve the modeling accuracy of flexible mechanism of the positioning stage is proposed,then,finite element simulation,multi-objective optimization and experiment of positioning stage are further carried out.The specific research contents of this paper are as follows:(1)A new two-degree-of-freedom decoupling large-stroke micro-nano positioning stage is designed.After the comparison and analysis of positioning stage configuration,compliant displacement amplification mechanism,and compliant guide mechanism,a new two-degree-of-freedom decoupled large-stroke micro-nano positioning stage is designed,The positioning stage has the characteristics of compact structure,decoupling of input and output and large positioning stroke.(2)The static model of compliant mechanism based on Euler Bernoulli beam theory and compliance matrix method and the dynamic model based on centralized mass method theory were established and verified by finite element simulation analysis.A static modeling method of compliant mechanism combining Euler Bernoulli beam theory with compliance matrix method is proposed,and a dynamic modeling method of positioning stage based on centralized mass method is proposed on the basis of the static model.Through multi-group finite element simulation analysis,it is proved that the model considering the flexibility of bar is more accurate in the prediction of mechanical properties,and the variation law between the size variation of the positioning stage and the displacement magnification and natural frequency of the positioning stage are analyzed.(3)The multi-objective genetic optimization algorithm is used to optimize the size parameters of the positioning platform structure,and the optimal solution set of the size parameters of the positioning stage structure is obtained,and the reliability of the static and dynamic model of the positioning stage is verified by comparing the optimization results of different models.Global sensitivity analysis method is used to analyze the influence of the structural dimensions of the compliant mechanism of positioning stage on the global model,find out the structural parameters that have great influence on the optimization objective,and determine the optimization design variables according to the analysis results.Determining the optimal constraints,then taking displacement magnification and natural frequency of positioning stage as the optimization objective,a multi-objective genetic optimization algorithm was used to obtain Pareto solution set,and by comparing and analyzing the optimization solutions of other models,it is proved that the unproved model can obtain more reliable optimization design scheme.(4)Finally,based on the theoretical and simulation analysis and optimization results,the experimental prototype is processed and a series of experimental tests are carried out on the working stroke,displacement magnification,output stiffness,decoupling performance and natural frequency.The experimental results verify the correctness of the theoretical model and the finite element simulation results.