TMT宽视场光谱仪准直镜系统的相似动力学分析与试验研究

Dynamics Analysis of Similarity and Experimental Study of Collimator System for TMT Wide Field Spectrometer

大型光机仪器难以在短期内实现加工,为了验证仪器设计的正确性,利用相似模型试验替代原型研究。基于相似定理,推导了三十米望远镜(TMT)宽视场光谱仪准直镜系统原型和缩尺模型之间的相似关系;建立了准直镜系统原型的有限元模型及1∶3缩尺模型的有限元模型,对二者进行了模态分析和面形分析,并对缩尺模型实物进行了相似模型试验和分析。研究结果表明,在1∶3的缩尺比例下,准直镜系统缩尺模型与原型的振型相似性符合理论分析结果;在工作环境下,缩尺模型的表面波前误差的均方根值为0.065λ(λ为波长)。模型试验结果证明准直镜系统的缩尺模型满足光学系统的工作要求。利用缩尺模型能够预测原型动态响应及面形变化,为后续项目的正式研究提供技术积累。

Large optomechanical instruments are difficult to process in short time.In order to verify the correctness of instrument design,the similarity model test was used to replace the prototype research.Based on the similarity theorem,the similarity relationship between the prototype and the scaled model of the collimator system in the Thirty Meter Telescope(TMT)wide field spectrometer was first derived.The finite element models of the prototype and the 1∶3 scaled model were then established,and the modal analysis and the surface analysis were conducted based on these two models.The similarity model test and the analysis for the scaled model object were finally performed.At the scale of 1∶3,the vibration mode similarities of these two models conform to the theoretical analysis results.The root mean square value of surface wavefront errors for the scaled model is 0.065λ(λis wavelength)in the working environment.The model test results prove that the scaled model of the collimator system can satisfy the requirements of an optical system,which can predict the dynamic responses and surface deformation changes of prototype.The study can provide technical accumulation for the formal research of subsequent projects.