State Key Laboratory of Precision Measurement Technology and Instruments

Beijing, China

State Key Laboratory of Precision Measurement Technology and Instruments

Beijing, China

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Li J.,Tsinghua University | Li J.,State Key Laboratory of Precision Measurement Technology and Instruments | Li J.,Collaborative Innovation Center for Micro Nano Fabrication | Liu Z.,Tsinghua University | And 4 more authors.
Applied Optics | Year: 2017

In on-board photographing processes of satellite cameras, the platform vibration can generate image motion, distortion, and smear, which seriously affect the image quality and image positioning. In this paper, we create a mathematical model of a vibrating modulate transfer function (VMTF) for a remote-sensing camera. The total MTF of a camera is reduced by the VMTF, which means the image quality is degraded. In order to avoid the degeneration of the total MTF caused by vibrations, we use an Mn-20Cu-5Ni-2Fe (M2052) manganese copper alloy material to fabricate a vibration-isolation mechanism (VIM). The VIM can transform platform vibration energy into irreversible thermal energy with its internal twin crystals structure. Our experiment shows the M2052 manganese copper alloy material is good enough to suppress image motion below 125 Hz, which is the vibration frequency of satellite platforms. The camera optical system has a higher MTF after suppressing the vibration of the M2052 material than before. © 2017 Optical Society of America.


Xiaohui M.,Tianjin University of Technology | Xiaohui M.,State Key Laboratory of Precision Measurement Technology and Instruments | Xiaoxia H.,Tianjin University of Technology | Xiaoxia H.,State Key Laboratory of Precision Measurement Technology and Instruments | And 3 more authors.
Journal of the European Ceramic Society | Year: 2016

Freeze casting was used to fabricate unoriented three dimension framework of fibrous porous ceramics. Compared with vacuum filtration, this method was helpful in keeping the original three-dimensional dispersion which led to both high porosity and strength. The results indicated that the optimum fibers and silica sol content were 2. vol% and 5. wt% respectively for mechanical and other properties. The high-temperature stability of fibrous porous ceramics prepared by freeze casting and vacuum filtration are discussed in this paper. The samples showed lower thermal shrinkage and better stability because of the three dimensional orientations under a high temperature environment with a pressure of 0.8. MPa. The maximal tolerable temperature of samples preparing by freeze casting had been as high as 1200. °C. © 2015 Elsevier Ltd.


Wei M.,Tsinghua University | Wei M.,State Key Laboratory of Precision Measurement Technology and Instruments | Wei M.,Collaborative Innovation Center for Micro Nano Fabrication | Xing F.,Tsinghua University | And 5 more authors.
Optics Express | Year: 2013

Stringent attitude determination accuracy through a high bandwidth is required for the development of the advanced space technologies, such as earth observation and laser communication. In this work, we presented a novel proposal for a digital sun sensor with high accuracy, large Field of View (FOV) and ultra-high data update rate. The Electronic Rolling Shutter (ERS) imaging mode of an APS CMOS detector was employed and an "amplifier factor" was introduced to improve the data update rate significantly. Based on the idea of the multiplexing detector, a novel mask integrated with two kinds of aperture patterns was also introduced to implement its distinctive performance of high precision and large FOV. Test results show that the ERS based sun sensor is capable of achieving the data update rate of 1 kHz and precision of 1.1? (1s) within a 105° ×105° FOV. The digital sun sensor can play an important role in precise attitude determination and provide a broader application for high accuracy satellites. ©2013 Optical Society of America. © 2013 Optical Society of America.


Nan C.,Tsinghua University | Nan C.,State Key Laboratory of Precision Measurement Technology and Instruments | Fei X.,Tsinghua University | Fei X.,State Key Laboratory of Precision Measurement Technology and Instruments | And 2 more authors.
Key Engineering Materials | Year: 2013

Along with the development of MEMS technology, the precision of MEMS-Gyro is increasing and the range of application of MEMS-Gyro is expanding. The accuracy of centroid determination of the spot directly relates to the precision of star tracker, but, when the exposure time is shorter or the satellite is in an unstable state, the noise of detector limits the accuracy greatly in the traditional approach of centroid determination. In view of these issues, this paper presents an approach which is based on high-precision MEMS-Gyro to determine the centroid of spot. This approach references EKF to estimate the position of centroid optimally. So, when the SNR is reduced because of shorter exposure and unstable state, this approach can help to increase the accuracy of centroid determination by introducing MEMS-Gyro. Further, it improves the precision and dynamic performance of the star tracker. In the end of this article, the feasibility of the approach is verified by the numerical simulation. © 2013 Trans Tech Publications Ltd, Switzerland.


Wang Z.,Beijing University of Technology | Yang Y.,Beijing University of Technology | Yang J.,Tsinghua University | Yang J.,Collaborative Innovation Center for Devices and Systems | Yang J.,State Key Laboratory of Precision Measurement Technology and Instruments
Mathematical Problems in Engineering | Year: 2015

Inertial navigation devices include star sensor, GPS, and gyroscope. Optical fiber and laser gyroscopes provide high accuracy, and their manufacturing costs are also high. Magnetic suspension rotor gyroscope improves the accuracy and reduces the production cost of the device because of the influence of thermodynamic coupling. Therefore, the precision of the gyroscope is reduced and drift rate is increased. In this study, the rotor of liquid floated gyroscope, particularly the dished rotor gyroscope, was placed under a thermal field, which improved the measurement accuracy of the gyroscope. A dynamic theory of the rotor of liquid floated gyroscope was proposed, and the thermal field of the rotor was simulated. The maximum stress was in x, 1.4; y, 8.43; min 97.23; and max 154.34. This stress occurred at the border of the dished rotor at a high-speed rotation. The secondary flow reached 5549 r/min, and the generated heat increased. Meanwhile, the high-speed rotation of the rotor was volatile, and the dished rotor movement was unstable. Thus, nanomaterials must be added to reduce the thermal coupling fluctuations in the dished rotor and improve the accuracy of the measurement error and drift rate. © 2015 Wang Zhengjun et al.


Cao L.,State Key Laboratory of Precision Measurement Technology and Instruments | Wang Z.,State Key Laboratory of Precision Measurement Technology and Instruments | Zong S.,State Key Laboratory of Precision Measurement Technology and Instruments | Zhang S.,Key Laboratory of Organic Photoelectrons and Molecular Engineering of Ministry of Education | And 2 more authors.
Journal of Polymer Science, Part B: Polymer Physics | Year: 2016

Holography is considered to be the next generation of technology to achieve true three-dimensional (3D) displays as it can reconstruct the wavefronts of light with the whole depth cues of a real 3D scene. Current updatable holographic materials lack multiplexing properties and fatigue resistance for 3D displays. We report on a new holographic material of side-chain diarylethene polymer with the thickness of 320 μm, minimum multiplexing angle of 0.17°, rapid response time of several seconds, and fatigue resistance. The updatable reconstructions of 3D scenes with write/erase cycles are realized in experiments. This thick photochromic polymer shows potential for applications such as real-time 3D displays for big data. © 2016 Wiley Periodicals, Inc.


Deng Y.,State Key Laboratory of Precision Measurement Technology and Instruments | Zhou B.,State Key Laboratory of Precision Measurement Technology and Instruments | Xing C.,State Key Laboratory of Precision Measurement Technology and Instruments | Zhang R.,State Key Laboratory of Precision Measurement Technology and Instruments
Sensors (Switzerland) | Year: 2014

A novel multifrequency excitation (MFE) method is proposed to realize rapid and accurate dynamic testing of micromachined gyroscope chips. Compared with the traditional sweep-frequency excitation (SFE) method, the computational time for testing one chip under four modes at a 1-Hz frequency resolution and 600-Hz bandwidth was dramatically reduced from 10 min to 6 s. A multifrequency signal with an equal amplitude and initial linear-phase-difference distribution was generated to ensure test repeatability and accuracy. The current test system based on LabVIEW using the SFE method was modified to use the MFE method without any hardware changes. The experimental results verified that the MFE method can be an ideal solution for large-scale dynamic testing of gyroscope chips and gyroscopes. © 2014 by the authors; licensee MDPI, Basel, Switzerland.


Zhang H.,State Key Laboratory of Precision Measurement Technology and Instruments | Liu C.,State Key Laboratory of Precision Measurement Technology and Instruments | Fu L.,State Key Laboratory of Precision Measurement Technology and Instruments | Guo Y.,State Key Laboratory of Precision Measurement Technology and Instruments
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Construction of high-speed railway in China has entered a period of rapid growth. To accurately and quickly obtain the dynamic envelope curve of high-speed vehicle is an important guarantee for safe driving. The measuring system is based on binocular stereo vision. Considering the difficulties in field calibration such as environmental changes and time limits, carried out a field calibration method based on fast reconstruction of three-dimensional control field. With the rapid assembly of pre-calibrated three-dimensional control field, whose coordinate accuracy is guaranteed by manufacture accuracy and calibrated by V-STARS, two cameras take a quick shot of it at the same time. The field calibration parameters are then solved by the method combining linear solution with nonlinear optimization. Experimental results showed that the measurement accuracy can reach up to ± 0.5mm, and more importantly, in the premise of guaranteeing accuracy, the speed of the calibration and the portability of the devices have been improved considerably. © 2015 SPIE.


Li R.,State Key Laboratory of Precision Measurement Technology and Instruments | Qu X.,State Key Laboratory of Precision Measurement Technology and Instruments
Jiqiren/Robot | Year: 2014

A measurement and control technology is presented to compensate the movement angle error for each axis of the robot. The effect significance of various factors on the movement angle error is discussed. The control error model of motor moving and the deformation error model of joint or link are analyzed independently. A measuring scheme based on biaxial orthogonal inertial measurement is proposed. In order to obtain the distribution of the space geometric error, the angle error of each robot axis is measured in the motion range of every axis in advance. Then the orthogonal polynomial fitting is used to establish the position error distribution model of each axis. An error compensation value is calculated using the proposed model before the robot runs, so as to control the robot for position compensation. The distribution law of each axis motion error in the robot and the way of orthogonal polynomial fitting are analyzed. The laser tracker is used to measure the compensation effect of the position accuracy of the robot end. The robot control accuracy can be improved by studying robot performance and its compensation.


PubMed | State Key Laboratory of Precision Measurement Technology and Instruments
Type: Journal Article | Journal: Sensors (Basel, Switzerland) | Year: 2014

A novel multifrequency excitation (MFE) method is proposed to realize rapid and accurate dynamic testing of micromachined gyroscope chips. Compared with the traditional sweep-frequency excitation (SFE) method, the computational time for testing one chip under four modes at a 1-Hz frequency resolution and 600-Hz bandwidth was dramatically reduced from 10 min to 6 s. A multifrequency signal with an equal amplitude and initial linear-phase-difference distribution was generated to ensure test repeatability and accuracy. The current test system based on LabVIEW using the SFE method was modified to use the MFE method without any hardware changes. The experimental results verified that the MFE method can be an ideal solution for large-scale dynamic testing of gyroscope chips and gyroscopes.

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