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Liu Y.,Beijing Aerospace Times Laser Inertial Technology Co. | Lang Z.,61081 PLA Troops | Tang W.,Harbin Institute of Technology
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering

A material surface roughness measurement system based on light-section principle and consisted of CCD camera and conventional light-section microscope as well as by using of VC development tool and image process technique was developed. Due to the characteristic that the image of the material surface roughness under light-section microscope had obvious directivity, the images were preprocessed by using of the spin filtering method and the roughness measurement results were compared with the ones based on the conventional filtering methods. The influences of the size of filter window and the filtering method on the tangent direction on measurement results were discussed at the same time. All parameters of the new national standard can be measured by using of this measurement system, and the on-line measurement can be realized. The calibration method of the system was introduced and the main error factors of influencing measurement precision were analyzed. The arithmetical mean deviation Ra which value was 3.2 μm was measured, and the result is 2.93 μm and the relative error is -8.5% which is less than the indicating value allowable error of the system. Source

Wang L.,Beihang University | Zhang C.,Beihang University | Gao S.,Beihang University | Wang T.,Beijing Aerospace Times Laser Inertial Technology Co. | And 2 more authors.

The dynamic Allan variance (DAVAR) [1] is a useful tool to track non-stationaries in the behavior of gyroscopes. It allows us to diagnose whether the stability of gyroscopes is changing with time. Unfortunately, with the length of the analyzed time series increasing, the computational time of the DAVAR grows very quickly. Consequently, it costs huge time to deal with the data. In this article, a Fast algorithm of the DAVAR for gyroscopes is developed. In order to verify its validity, three sets of simulation data are characterized by the Fast algorithm and the classical one. The Fast DAVAR could reduce the computational time dramatically when the long time series is analyzed. Furthermore, a vibration experiment with fiber optic gyroscopes has been implemented to validate the good performance of the Fast algorithm. Compared with the classical one, the Fast algorithm of the DAVAR shortens the computation time 6 times. In conclusion, the Fast algorithm of the DAVAR guarantees a dramatic reduction of the computational time and outperforms the classical DAVAR. © 2015 Elsevier GmbH. All rights reserved. Source

Qu D.-D.,Beijing Institute of Technology | Qu D.-D.,Beijing Aerospace Times Laser Inertial Technology Co. | Zhao Y.-J.,Beijing Institute of Technology | Ren Y.,China Science and Technology Museum
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering

Foldable segmented mirrors satisfy the requirement of next generation telescope which requires larger, lighter and foldable. Detecting the piston error between individual segments with high accuracy is critical to avoiding the image degradation due to segments misalignment with large mirrors. It is also critical to realize the grand scale of the segment mirror. The relationship of piston error and the distance of the main peak point of diffractive spot from the center point of image was proved to be linear within one wavelength range. A method to detect the piston error based on the location of the main peak of diffraction theory was presented. The optical system was simple and the measurement accuracy was high. The accuracy of the peak location was required high enough to satisfy the requirement for piston detecting of segmented mirrors. A peak location method based on Gaussian fitting was used and the location accuracy may arrive to 600 nm on the condition of 10 sampling points or so with the sample interval of 5 μm. The experimental results show that it is a valid method to detect the piston error of the segmented mirrors. The measurement accuracy of piston can achieve within one wavelength range. Source

Shi J.,Beijing Aerospace Times Laser Inertial Technology Co.
2011 IEEE International Conference on Information and Automation, ICIA 2011

According to the accumulation characteristic of SINS positioning error caused by inertial sensor error, this paper brought the rotation monitor technique to improve the SINS accuracy. Dual-axis consequential rotation scheme is designed by deeply analyze toward the existing single-axis and two-axis scheme. This scheme is selected as the final scheme by analyzing modulation results of constant gyro drift, the gyro scale error and the deviation of the gyro installation error. Computer simulation shows that this scheme has better modulation than single-axis and two-axis continuous scheme and can improve position accuracy of SINS effectively. © 2011 IEEE. Source

Sun P.,Inner Mongolia University of Technology | Xing Z.,Inner Mongolia University of Technology | Wang H.,Beijing Aerospace Times Laser Inertial Technology Co. | Zhang Y.,Inner Mongolia University of Technology | Gao J.,Inner Mongolia University of Technology
Taiyangneng Xuebao/Acta Energiae Solaris Sinica

From the perspectives of engineering, taking the blade of certain 1.5 MW wind turbine as the research object and the most optimal structure performance as target, using the combining method of theoretical analysis, finite element analysis and structural optimization, applying hierarchical optimization strategy, the optimal mathematic model, objective function and constraint condition were established. The optimal lamination scheme of blade was obtained by optimizing lay-up angle, lay-up thickness and lay-up sequence, respectively. The structure analysis results indicate that the maximum principal stress and strain of the optimized blade are reduced obviously, respectively. The correctness and effectiveness of the optimization scheme and method are verified. ©, 2015, Science Press. All right reserved. Source

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