Thermal-mechanical Coupling Simulation And Structure Optimization Of High-precision Two-axis Turntable

This paper mainly studies the mechanical structure of the two-axis turntable.Through the analysis of mechanical characteristics and thermal-mechanical coupling analysis,the effect of the maximum strain on the test accuracy is carried out.Multiobjective optimization of the frame structure size is carried out to obtain a turntable structure that meets the performance and functional requirements.According to the analysis of the mechanical characteristics of the turntable and the results of the thermal-mechanical coupling analysis,the response surface method is used to optimize the structure of the inner and outer frames of the turntable.The sensitivity of the target parameters to the output parameters and the trend between the two are analyzed through effective design points.relationship.The optimal design point is selected from the three sets of optimization results obtained by the simulation calculation of the DOE method.Through the multi-objective optimization solution to the optimal design point,the results show that:1)The most important structural variable that affects the mechanical properties of the inner frame is the thickness.After optimization,the maximum strain of the inner frame is 8.63 μm,which has little effect on the test accuracy;the maximum stress is0.255 MPa,which is less than the allowable stress of cast aluminum alloy and meets the strength of the structure.And stiffness requirements;after the modal calculation results are compared with the initial structure calculation,the optimized first-order modal has increased by 28.7%,and the mass has been reduced by 11%.2)The structural variable that affects the mechanical properties of the outer frame the most is the width.After optimization,the maximum strain of the inner frame is4.05μm,which has little effect on the test accuracy;the maximum stress is 1.02 MPa,which is lower than the allowable stress of cast aluminum alloy and meets the structural requirements.Strength and rigidity requirements;after comparing the modal calculation results with the initial structure calculation,the optimized first-order modal has increased by 16.8%,and the mass has been reduced by 8.8%.In summary,after optimizing the frame of the two-axis turntable,the key and noncritical variables that affect the mechanical properties of the frame are found,while reducing the maximum strain of the structure,increasing the first-order modal frequency,and significantly reducing the frame quality,So as to achieve the purpose of multi-objective optimization,and effectively improve the frame structure performance of the two-axis turntable.