中国科学院机构知识库网格系统: 检索

A NONLINEAR OPTIMIZATION ALGORITHM FOR EVALUATING THE PERFORMANCE OF MICROWAVE IMAGER COMBINED ACTIVE/PASSIVE 会议论文 OAI收割
Fort Worth, TX, JUL 23-28, 2017
作者: Zhang, Lan-jie; Wang, Zhen-zhan; Zhang, Ruan-yu; Yin, Xiao-bin

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收藏 | 浏览/下载：27/0 | 提交时间：2018/05/04

Micap Nonlinear Optimization Algorithm Sss Rms Error

Structural design of large aperture rectangular mirror for space telescope (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Civil Engineering and Transportation, ICCET 2012, October 27, 2012 - October 28, 2012, Guilin, China
作者: Li Z.; Li Z.

收藏 | 浏览/下载：43/0 | 提交时间：2013/03/25

Structural design of large aperture mirror is one of the key technologies for space telescope development. To meet the requirements of high stiffness strength and thermal dimensional stability some factors such as support scheme materials selection lightweight design and flexible support design were taken into account. The three supports location of the mirror was determined according to the modal analytical solution. By adjusting the parameters of flexure hinge influences of gravity assembly stress and thermal stress on the mirror were reduced obviously. Finite element analysis (FEA) results indicate that the surface accuracy reach to rms10.2nm and 10.8nm under the gravity along optical axis direction and 5C uniform temperature rise respectively the fundamental frequency of the mirror component is 268Hz. Dynamics test shows that the first order natural frequency is 256Hz which shows an error less than 5% compared to FEA results. (2013) Trans Tech Publications Switzerland.

Surface shape optimization for the space membrane reflector (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electronic and Mechanical Engineering and Information Technology, EMEIT 2011, August 12, 2011 - August 14, 2011, Harbin, China
作者: Zhang Y.; Zhang P.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

Space membrane reflector is very promised for optical quality application with the merits of ultra-lightweight and flexible. In order to improve the surface precision of membrane reflectors the formation and surface shape error of a membrane at uniform load are studied based on the henky-cambell equations of circular membrane. The ANSYS software is used to build an optimization model of membrane reflector surface shape in which the yield strength is the state variable the surface load on ten concentric annular regions of the mirror is the design variable and the minimum RMS between ideal surface and mirror surface is the target function. and the theoretical and experimental result show that RMS and PV of the optimized surfaces are reduced respectively than those before optimization. In a word this paper offers the theoretical and experimental basis of the polyimide membrane reflector. 2011 IEEE.

Design and test of pointing mirror assembly for spaceborne remote sensing camera (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electronics, Communications and Control, ICECC 2011, September 9, 2011 - September 11, 2011, Ningbo, China
作者: Chen W.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

In order to ensure the surface figure of the pointing mirror (460mm long 290mm wide) in spaceborne remote sensing camera Silicon Carbide was selected as the mirror material. The form of composite triangular and rectangular and the combination of open and closed back was explored in the lightweight design. A new kinematic mount and flexible structure in axis is used to hold the mirror around the lateral surface. The structure can minimize distortions induced by coefficient of thermal expansion mismatch among the materials. This eliminates the bending of the integral mount under the weight of the mirror. Optical performance of the mirror was analyzed under gravity load and temperature load using finite element method. Predicted surface figure error based on the removal of bias tilt and power was calculated using an in-house Matlab script for mirrors. The pointing mirror assembly was tested using open loop servo control. And the surface figure was checked using interferometer. Surface figure accuracy is better than 1/30 ( 632.8nm rms). The results show that the kinematic mount induces minimal figure error on the optical surface. 2011 IEEE.

Brazing RB-SiC used in large aperture space optical system (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Materials and Products Manufacturing Technology, ICMPMT 2011, October 28, 2011 - October 30, 2011, Chengdu, China
Zhang B.; Zhang Z.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

Because of the sic material's superior optical characteristic machine characteristic and hot characteristic it becomes currently the space big aperture reflector choose firstly1. For larger aperture sic mirror it is not economical and safe to make the monolithic body directly 2 3. The SiC mirror brazed assembly with several segments can solve these problems. In this paper one 600 mm sic plane mirror as demonstration welded with 3 radial segments is roughly grinded to the required figure at first then the mirror is finely grinded and polished by the technology of CCOS the mirror figure error is less than 1/20 ( = 632.8nm) in RMS finally. The problems of the preferential removal near braze joint are solved. The methods of reducing the residual stress of mirror are discussed. At last some measurements and experiments are carried on and the results conclude that the brazed SiC mirror can meet the requirement of large aperture optical systems. (2011) Trans Tech Publications.

Research of active supporting technology based on 400mm thin mirror (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, April 26, 2010 - April 29, 2010, Dalian, China
作者: Liu X.-Y.; Wang J.-L.; Wang J.-L.; Liu X.-Y.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

Using a spherical mirror of 400mm diameter and 12mm thickness active supporting technology of thin mirror is researched. The axial support of the mirror is composed of 12 active supports and 3 fixed supports. The force actuator which is composed of displacement actuator and force sensor is installed in the active support. The mirror surface is tested by Zygo interferometer. For calibration each actuator exerts unit force alone and the surface variation is tested and taken as the response function of the actuator. The response functions of all actuators compose the stiffness matrix. Then the stiffness matrix is used by damped least square method to determine the correction force of each active support. In order to analyze the correction capability of the active supports 14 Zernike modes of the mirror surface are generated and tested respectively and 7 modes are selected for correction. Initially the RMS error of mirror surface is 1.16 I( =0.6328nm)when all actuators exert the same force. After 5 iterations the RMS error of mirror surface is reduced to 0.13 close to the original surface quality. 2010 Copyright SPIE - The International Society for Optical Engineering.

In situ long trace profiler for measurement of Wolter type-I mirror (EI CONFERENCE) 会议论文 OAI收割
Advances in Metrology for X-Ray and EUV Optics III, August 1, 2010 - August 2, 2010, San Diego, CA, United states
作者: Chen B.; Chen B.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

The surface profile of Wolter type-I mirror has a great impact on the performance of Solar X-ray Telescope. According to the existing fabrication instrument and experimental conditions in our lab an in situ Long Trace Profiler is developed and set up on the fabrication instrument in order to measure the surface profile of Wolter mirror in real time during fabrication process. Its working mechanism structural parameters and data processing algorithm are investigated. The prototype calibrated by a standard plane mirror is used to measure a sample of Wolter type-I mirror. The results show that our prototype can achieve an accuracy of 2.6rad rms for slope error with a stability of 1.33rad during the whole measurement period. This can meet further fabrication requirements. 2010 Copyright SPIE - The International Society for Optical Engineering.

Design and fabrication of CGH for aspheric surface testing and its experimental comparison with null lens (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhao J.; Zhang X.; Zhang X.; Zhang X.; Li F.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

Computer-generated hologram (CGH) is an effective way to compensate wavefront in null test of aspheric surfaces and freeform surfaces. Our strategies of CGH design and fabrication for optical testing are presented and an experiment demonstrating the compensation results of CGH and null lens is also reported. In order to design complex CGH software was developed with which we can design a CGH including three sections: main section for compensating wavefront in null test alignment section for adjusting the relative position between CGH and interferometer and fiducial section for projecting fiducial marks around the optics under test. The design result is represented in GDS II format file which could drive a laser-direct-writer- machine to fabricate a photomask. Then a 1:1 replication process is applied to duplicate the patterns from photomask to a parallel optical substrate whose surface is error better than /60 rms. Finally an off-axis aspheric surface was tested with CGH and null lens respectively. The test result with CGH (0.019rms) is almost the same as the result with null lens (0.020 rms). This experiment also demonstrated that fiducial marks projected by CGH can be used to guide the alignment of the optics and measurement of its off-axis distance. 2010 Copyright SPIE - The International Society for Optical Engineering.

Novel method for optimizing polishing tool-path in CCOS based on weighted-iterative algorithm (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Zhang X.-J.; Wang X.; Wang X.; Wang X.; Wang X.-K.

收藏 | 浏览/下载：40/0 | 提交时间：2013/03/25

In Computer Controlled Optical Surfacing (CCOS) polishing tool-path is the base of solving other control parameters such as dwell time. In order to improve the fabrication results of polishing off-axis aspheric a novel method to optimize the tool-path is discussed in this paper. The optimizing method named weighted-iterative algorithm is according to the balance principle of the particle system. The power factor of each dwell point represents the requirement of dwell density. Considering the factors which influence the polishing result the power factors cosist of three elements include constant error distribution and dwell distance of workpiece edge. The tool-path is solved by numerical iterative method. In the end an error data is simulated with actual parameters using the matrix-based algorithm with two different tool-paths. The one is X-Y uniform spacing model and the other one is to optimize it based on the first. The comparison shows that the results of the optimized one are much better than traditional one especially the rms convergence rate. Theory of the algorithm is simple and exercisable and it satisfies practical requirement as well. 2009 SPIE.

Fabrication and testing 600mm diameter brazing SiC mirror (EI CONFERENCE) 会议论文 OAI收割
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, November 19, 2008 - November 21, 2008, Chengdu, China
作者: Wang X.; Zhang X.-J.; Zhang Z.-Y.; Zhang Z.-Y.; Wang X.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

SiC is a preferential material for space large aperture mirror at present. Aperture of 1 meter sic mirror can meet most requirements of space optical systems. For larger aperture sic mirror it is not economical and safe to make the monolithic body directly. The SiC mirror brazed assembly with several segments can solve these problems. In this paper one 600 mm sic plane mirror as demonstration welded with 3 radial segments is roughly grinded to the required figure at first then the mirror is finely grinded and polished by CCOS technology the RMS of the figure error is less than 1/20 ( = 632.8nm) finally. The problems of the preferential removal near braze joint and material removing rate influenced by deformation of mirror surface are solved. Methods of reducing the residual stress of mirror are discussed. At last some measurements and experiments are carried on and the results conclude that the brazed SiC mirror can meet the requirement of large aperture optical systems. 2009 SPIE.