摘要
针对传统迈克尔逊干涉仪动镜支撑结构存在成本高、寿命低、维护难度大、大行程大负载下导向精度差的问题,设计了一种高精度迈克尔逊干涉仪角镜柔性支撑结构,具有低成本、高精度、大负荷的优点。提出以柔性支撑结构的承载能力、行程和导向精度为优化目标的结构刚度模型,选择材料和尺寸参数,开展运动结构设计。有限元分析结果表明该支撑结构在1.5 kg的负载(角镜)下,当行程达到4.5 mm时,柔性结构的最大拉应力约为169 MPa,结构安全裕量为1.98,角镜竖直方向的寄生位移小于4.1μm。专项测试结果显示,支撑结构承载1.5 kg负载(角镜)在4.5 mm行程内,竖直方向的寄生位移小于4.7μm,直线度的均方根误差为1.5μm,与设计结果较吻合,可以满足星载迈克尔逊干涉仪对高精度直线动镜的支撑要求。
The support structure of the moving mirror constitutes the most crucial component of the highprecision Michelson interferometer,exerting a decisive impact on the quality of the interference signal.Conventional moving mirror support is accomplished through mechanical guide rails or magnetic levitation in combination with a drive motor,which is expensive,difficult to maintain,has a low life span,and has low guiding accuracy under the load of large mass and large stroke angle mirrors.To address these issues,a flexible support structure for the moving mirror of the Michelson interferometer is designed,featuring low cost,high precision,large load capacity,and large travel range.In this paper,the working principle of the Michelson interferometer is presented,and the impacts of the travel of the moving mirror,guiding accuracy,and velocity uniformity on the accuracy and stability of the interferometer are analyzed.The influence of the parasitic displacement perpendicular to the direction of motion on the parasitic path difference is quantified when the angle mirror is employed as the moving mirror.With the parallelogram guiding structure serving as the basic prototype,four parallelogram structures are nested both internally and externally to form the fundamental framework of the support structure,effectively amplifying the motion stroke of the entire structure.The flexible support structure is arranged symmetrically to counteract the parasitic displacement in the horizontal direction.Taking the load capacity,travel,and guiding accuracy of the flexible support structure as the optimization targets,the structural stiffness model is proposed.Based on the Awtar beam constraint model,the force-displacement relationship of the flexible reed with unilateral constraint is derived from the deformation mechanism of the cantilever beam,and subsequently,the stiffness formula of the flexible reed with unilateral constraint is deduced.The stiffness model of two unilateral constrained flexible reeds is obtained by means of Hooke's law.On this basis,the stiffness model of the entire flexible structure is derived in accordance with the series-parallel relationship of the flexible reeds in the flexible support structure.The finite element method combined with the stiffness model of the flexible structure is utilized to optimize the size parameters of the structure,and the transition fillet is set at the connection of the flexible reed and the rigid part to mitigate the stress concentration phenomenon.By comparing the ratios of yield strength to elastic modulus of different materials,7075 aluminum alloy is determined as the optimal material for the structure,and the three-dimensional model design and simulation of the flexible structure are conducted.The finite element analysis results indicate that the maximum tensile stress of the flexible structure amounts to 169 MPa,the structural safety margin is 1.98,and the parasitic displacement perpendicular to the movement direction is less than 4.1μm when the travel attains 4.5 mm under the load of 1.5 kg(angle mirror).A special test platform was established by means of a spiral micrometer,a high-precision grating scale meter,a digital dynamometer,and weights.The forcedisplacement relationship and parasitic displacement of the test pieces were examined,and the errors between the simulation results and the experimental results were analyzed.The results demonstrate that the parasitic displacement perpendicular to the motion direction is less than 3.2μm and 4.7μm,and the rootmean-square error of straightness is 0.96μm and 1.5μm respectively when the flexible support structure is subjected to 0.5 kg and 1.5 kg load(angle mirror)within the range of 4.5 mm travel.The test results of this structure are consistent with the design results,and can meet the support requirements of the satelliteborne Michelson interferometer for high-precision linear moving mirrors.It can also be used in other motion systems that require large stroke,large load,long life,and high guiding accuracy.
作者
杨帅
孙剑
严强强
冯玉涛
田飞飞
郝雄波
畅晨光
朱军
王灵杰
姚舜
YANG Shuai;SUN Jian;YAN Qiangqiang;FENG Yutao;TIAN Feifei;HAO Xiongbo;CHANG Chenguang;ZHU Jun;WANG Lingjie;YAO Shun(Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences,Xi'an 710119,China;University of Chinese Academy of Sciences,Beijing 100049,China;DFH Satellite Co.,Ltd,Beijing 100094,China;Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Sciences,Changchun 130033,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2024年第10期203-212,共10页
Acta Photonica Sinica
基金
民用航天项目(No.D010206)。
关键词
迈克尔逊干涉仪
动镜
柔性支撑结构
刚度模型
寄生位移
Michelson interferometer
Moving mirror
Flexible support structure
Stiffness model
Parasitic displacement
