Design Of Compliant Mechanisms Using Evolutionary Structural Optimization Method And Performance Test

Compliant mechanism is a kind of integral structure that transmits the input force or displacement to the drive end through elastic deformation.It has the advantages of high integration,no friction,and low noise,applying for a wide range of high-precision fields such as aerospace,medical and MEMS.With the continuous advancement of technology,the current performance of compliant mechanism needs to basically meet: high positioning accuracy,sufficient travel,strong fatigue resistance,good manufacturability,etc.And correspondently design of compliant mechanism with better performance has always been a research hotspot.This paper carries out the work on the topology optimization design method of the compliant mechanism,and verifies the mechanical driving performance of the optimized compliant mechanism through experiments.Further,the design method is extended to consider the piezoelectric component drive and the optimization design of the compliant mechanism considering the geometric nonlinearity.The full text is divided into the following four parts:First,an evolutionary topology optimization design method for compliant mechanism is developed.The convenient control of the driving performance and stiffness characteristics of the design mechanism is realized by defining an optimized objective function weighted by the driving displacement and stiffness characteristics(compliance),which effectively suppresses the formation of the hinge and prevents stress concentration of causing mechanism failure.In addition,the gradual(design iteration step)attenuation of the contribution of the stiffness characteristic realizes the dynamic evolution of the optimization problem from stiffness design to drive design.Two typical examples prove that the method is stable and efficient.Secondly,compliant mechanism has been manufactured and then tested its performance.On the basis of the mechanism configuration obtained by the aforementioned optimization design,an experimental platform for testing the optimized configuration’s efficiency of different weighting coefficients was built.The design configuration is reconstructed into a three-dimensional model through computer-aided geometric modeling,and the compliant mechanism samples are processed of photosensitive resin by 3D printing technology.In the experiment,piezoelectric devices are used to provide drive force,and the test effect is calibrated by drive displacement.The experimental results prove that the optimized configuration without hinge phenomenon significantly improves the stiffness performance of the structure at the expense of a certain driving displacement compared to the optimized configuration with hinges.Then considering the design of compliant mechanism combined with piezoelectric component,an evolutionary optimization design strategy that combines the stiffness of the mechanism in order to maximize the displacement of the output end is proposed.Specifically,the piezoelectric material is first refined into a two-dimensional plane stress model,and a piezoelectric-driven compliant mechanism design model is further proposed.Then combined with the adjustable stiffness performance of the mechanism,the stability of the algorithm and the manufacturability of the design configuration are improved.Two basic examples prove the effectiveness of the design method.Finally,in order to design compliant mechanism with more prominent strokes,the compliant mechanism design method previously limited to the geometric linear stage of the material is extended to the geometric nonlinear stage.The geometric nonlinear content was introduced,and the joint debugging platform of MATLAB and ANSYS was debugged and developed.Furthermore,numerical examples prove that the design configuration combining geometric nonlinear has a larger drive displacement.