Design Of Thermal Drift Coefficient Test System For Laser Interferometer

With the development of ultra-precision engineering and nanotechnology,laser interferometry technology is to high acceleration,high speed,sub-nano precision direction.In ultra-precision interferometric applications,the optical thermal drift of the mirror group has a significant effect on laser interferometry due to the asymmetry of the interferometric group.With the development of laser interferometer group,especially the appearance of non-coaxial optical path laser interferometer group,the interference mirror group becomes more and more complicated,while the thermal drift of the mirror group also affects the interference a major factor in measuring accuracy.And the laser interferometer group is a light machine system,in addition to the optical thermal drift,the interference mirror group there are still possible mechanical thermal drift,due to the heat expansion and refractive index can't consider other factors,the theoretical simulation and the actual heat drift of the mirror group a certain deviation.The actual thermal drift coefficient of the laser interferometer group can not only reflect the overall thermal drift of the laser interferometer as a light machine system,but also provide a strong guarantee for the precision measurement of the ultra-precision laser interferometry.In this paper,the mechanism and characteristics of thermal drift of laser interferometer are analyzed.On this basis,the error source and system design requirements of thermal interference coefficient test system of laser interferometer are analyzed.Secondly,aiming at the problem that the thermal drift coefficient of the laser interferometer group is affected by the ambient temperature gradient during the test,a low temperature gradient thermal structure with temperature uniformity is designed and the thermal drift test of the laser interferometer is designed and implemented based on the model predictive control principle System temperature control algorithm.Finally,based on LabVIEW,a test system is designed to complete the design of the thermal drift coefficient of the laser interferometer group in order to evaluate the influence of the thermal drift of the mirror group on the interferometric measurement and to provide a test tool for the thermal drift of the mirror group.The main research contents of this subject are as follows:(1)Based on the principle of laser heterodyne interferometry,the thermal drift formation mechanism and its characteristics of the laser interferometer group are analyzed,and the thermal interference of the laser interferometer is analyzed with the laser interference mirror and the typical laser interferometry.The ultrafast laser interferometry The impact of precision and the necessity of its testing.On this basis,the error source of the thermal drift coefficient test system of the laser interferometer group is analyzed and the system design requirements are given.(2)Aiming at the influence of the thermal drift coefficient of the laser interferometer group on the temperature gradient,a thermal structure with low temperature gradient is designed.The mechanical parameters of the thermal structure are optimized by ANSYS simulation,The temperature distribution of the path is as uniform as possible,reducing the error of the thermal drift coefficient of the interferometer in the testing process.(3)Based on the principle of model predictive control,the temperature control algorithm of thermal interference test system for laser interferometer is designed and implemented.Design of the system power drive module,based on LabVIEW real-time control algorithm operating platform.(4)On the basis of the above research,this paper designs and sets up the thermal drift coefficient test system of the laser interferometer group,and tests the thermal drift coefficient test system of the designed laser interfer ometer.The experimental results show that: The thermal drift coefficient of the test group is 10.34nm/?@25?.