中国科学院机构知识库网格系统: 检索

The design of aerial camera focusing mechanism 会议论文 OAI收割
applied optics and photonics, china: optical test, measurement, and equipment, aopc 2015, beijing, china, 2015-05
作者: Hu, Changchang; Yang, Hongtao; Niu, Haijun

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Focusing mechanism focusing accuracy ball screws lightw eight

Design and experimental research of a new type focus mechanism used in space-based telescope (EI CONFERENCE) 会议论文 OAI收割
2012 9th IEEE International Conference on Mechatronics and Automation, ICMA 2012, August 5, 2012 - August 8, 2012, Chengdu, China
作者: Wang D.

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The position of focal plane will be changed because of temperature fluctuation and vacuum environment. In order to make the telescope work well positioning accuracy of the mechanism is 0.008mm. The performance satisfies the need of precision a focusing mechanism is needed. To majority of large space-based telescopes and the scheme design is reasonable and practicable. 2012 IEEE. the general way to do this would be to use a reflector which was located in the backfocal distance. One of typical schemes of this mechanism was introduced however because of the big axial size the mechanism can't be used when the size of the enclosure was limited. A new type of focusing mechanism was introduced which has such advantages of small size high accuracy and low mass. The design and test methods had been discussed. According to the results the repeatability positioning accuracy is 0.0025mm

Design and analysis of auto-focus 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.; Gao X.

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Spaceborne remote sensing camera may be out of focus when the environment and photographic distance changes. In order to get higher ground sampled distance for the camera based on the experience gained from the development of a remote sensing camera working principle of auto-focus assembly control system was discussed. Time of waveform extraction was reduced. It sets force an auto-focus assembly that uses cam and line guide rail in order to move the lens group. The motion error of the auto-focus assembly was difficult to be eliminated and would affect on the focusing accuracy of the spaceborne remote sensing camera directly. So it was analyzed at both ends of the focusing structure. The CCD detector can keep stable when the remote sensing camera is imaging. The motion error was tested to verify the validity of the simulation result and it is less than 0.01mm. Its accuracy meets using demand. The focusing method of moving focal plane is suitable for spaceborne remote sensing camera. 2011 IEEE.

Accuracy analysis and optimization design of constant-diameter cam (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electric Information and Control Engineering, ICEICE 2011, April 15, 2011 - April 17, 2011, Wuhan, China
Yuan G.-Q.; Ding Y.-L.; Hui S.-W.; Liu Z.-H.; Li Y.-W.

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A constant-diameter cam gets its name because the centers of the rollers are a constant distance apart. This paper presents an Accuracy analysis and optimization design method for constant-diameter cam mechanism. Factors affecting the accuracy of cam are studied in the paper. The influences of the roller radial runout cam machining error and the base circle radius on accuracy are analyzed. Then a method to guarantee the cam diameter constant and remove return stroke error is studied using least-squares method. The analysis results indicate that the focusing accuracy can reach 4.4m and the return stroke error can reach 4.8m the functioning of institutions is stable and reliable. 2011 IEEE.

Analysis of a diffractive microlens using the finite-difference time-domain method (EI CONFERENCE) 会议论文 OAI收割
作者: Liu Y.; Liu H.; Liu H.; Liu H.; Liu Y.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

The finite-difference time-domain (FDTD) method is used as rigorous electromagnetic analysis model to calculate the field for a diffractive microlens (DML). The FDTD is used for the entire solution rather than using a near- to far-field propagation method to obtain the far-field energy distribution thus all the results are vector based. We derived a formula to calculate the magnitude of electric field which is time dependent and can be used to graphically show the light wave propagation and focusing process through a DML. Both the comparison and the integral methods are presented to obtain wave amplitude in full solution space and the distribution of light energy behind a DML is illustrated based on the wave amplitude. The formula of diffractive efficiency of the DML is derived from a time-averaged Ponyting vector which can indicate the propagation direction of light energy. Application of these formulations in the analysis of a DML example demonstrates the high accuracy and efficiency of our method. 2010 Society of Photo-Optical Instrumentation Engineers.

Focusing control system of photoelectric theodolite based on CAN bus (EI CONFERENCE) 会议论文 OAI收割
2010 2nd International Conference on Computer Engineering and Technology, ICCET 2010, April 16, 2010 - April 18, 2010, Chengdu, China
Mi Y.

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The development trend of focusing control system is high speed reliable control and miniaturization. A new autofocusing control system based on CAN bus is designed which realizes the real-time communication and synchronization control among the distributed control system. A design process of CAN interface based on TJAI050 is presented. The principle of focusing control and the hardware and software design are presented in detail. All experiments show that the control system has the advantages such as high accuracy and anti-interference ability and meets the requirements of high speed and good stability. 2010 IEEE.

Application of precision harmonic gear drive in focusing mechanism of space camera (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Smart Structures and Materials in Manufacturing and Testing, April 26, 2010 - April 29, 2010, Dalian, China
作者: Zhang X.; Zhang X.; Zhang X.

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A kind of precision harmonic gear drive in the focusing mechanism of space camera is studied which adopt external meshing complex wave transmission mode. Wave generator is combined with an elliptic cam and a flexible bearing around it. Flexspline is a structure of single wave with the same teeth. The output shaft is supported by a single cross-roller bearing. Ball screws connected the output shaft translate the rotational motion to the linear motion and drive the focusing mirror repeated moving along the linear guide. The output rigid wheel is connected with absolute encoder to detect displacement of focusing movement. It has the characteristics of big transmission ratio high precision compact structure high efficiency and smooth running etc. According to the practical application of this harmonic gear drive in the space camera the location relationship between the displacement of focusing structure and the focal plane movement is derived and the system error is analyzed its accuracy is tested with the open-loop control method. Experimental results show that transmission ratio of the instrument is 1:70 repeated positional accuracy is 2m which meet the requirements for use. 2010 SPIE.

Inspection focus technology of space tridimensional mapping camera based on astigmatic method (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, April 26, 2010 - April 29, 2010, Dalian, China
作者: Wang Z.; Wang Z.; Zhang L.; Zhang L.

收藏 | 浏览/下载：23/0 | 提交时间：2013/03/25

The CCD plane of the space tridimensional mapping camera will be deviated from the focal plane(including the CCD plane deviated due to camera focal length changed) under the condition of space environment and vibration impact when satellite is launching image resolution ratio will be descended because defocusing. For tridimensional mapping camera principal point position and focal length variation of the camera affect positioning accuracy of ground target conventional solution is under the condition of vacuum and focusing range calibrate the position of CCD plane with code of photoelectric encoder when the camera defocusing in orbit the magnitude and direction of defocusing amount are obtained by photoelectric encoder then the focusing mechanism driven by step motor to compensate defocusing amount of the CCD plane. For tridimensional mapping camera under the condition of space environment and vibration impact when satellite is launching if the camera focal length changes above focusing method has been meaningless. Thus the measuring and focusing method was put forward based on astigmation a quadrant detector was adopted to measure the astigmation caused by the deviation of the CCD plane refer to calibrated relation between the CCD plane poison and the asrigmation the deviation vector of the CCD plane can be obtained. This method includes all factors caused deviation of the CCD plane experimental results show that the focusing resolution of mapping camera focusing mechanism based on astigmatic method can reach 0.25 m. 2010 Copyright SPIE - The International Society for Optical Engineering.

Design and test of focusing mechanism of space camera (EI CONFERENCE) 会议论文 OAI收割
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Design, Manufacturing, and Testing of Micro- and Nano-Optical Devices and Systems, April 26, 2010 - April 29, 2010, Dalian, China
作者: Li Y.; Li Y.; Li Y.; Wang H.; Wang H.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

According to the focal depth and work environment of a space camera a focusing mechanism is designed which consists of precision screw ball transmission and linear bearing guidance and accuracy improving. The dynamic- strike- resistance adaptability to temperature and vacuum are considered into the reliable design method. Furthermore the linearity error the structure stability and the mechanism work situation in high and low temperature are tested. The result is that the linearity error of the mechanism is less than 0.003 mm and the sway error of vertical way and level way of the mirror is less than 20''. The linearity error of the mechanism and the sway error of the mirror remain unchanged after vibration test. The mechanism can work in the complex space environment. 2010 SPIE.

Rigorous vector analysis of diffractive microlens by using of finitedifference time-domain method (EI CONFERENCE) 会议论文 OAI收割
2009 International Conference on Optical Instruments and Technology, OIT 2009, October 19, 2009 - October 22, 2009, Shanghai, China
作者: Liu Y.; Liu H.; Liu H.; Liu H.; Liu Y.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

We use finite difference time domain (FDFD) method as rigorous vector analysis model to simulate the focusing process of diffractive microlens (DML). Differing with most analysis model which the near field distributions are calculated by FDTD and then far field are obtained by using of propagation method we obtain the fields in whole computational space by using of FDTD only. The advantages are that all the results are vector based and the computational time is saved greatly. In this paper we present two methods to obtain wave amplitude one is comparison method and the other is integral method. Depending on wave amplitude in the whole computational space one can conveniently obtain distributions of electric field intensity and calculate the time-average Poynting vector. We also present the formulation for calculating diffractive efficiency of DML based on time-average Poynting vector which denotes energy flow. As demonstration a DML is analyzed by using of these algorithms. The time depended graphic results of FDTD show the process of wave propagation. The distribution of electric field intensity illustrates the focusing of the normal incident light. The focus pattern in the focal plane is also show. The diffractive efficiency of the DML is calculated by using of the energy flow method in this paper. The results show the high accuracy and efficiency of the model. 2009 SPIE.