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Yang C.,Nankai University | Zhang H.,Nankai University | Liang H.,Beijing Aerospace Control Instrument Research Institute | Liu B.,Nankai University | And 5 more authors.
IEEE Photonics Technology Letters | Year: 2014

The photoisomerization effect of the azo functional material is introduced into a solid-core microstructured optical fiber (MOF) by infiltrating the N-Ethyl-N-(2-hydroxyethyl)-4-(4-nitrophenylazo) aniline (Disperse Red 1)-chloroform mixture solution into its cladding air holes. The irradiation laser power density as well as temperature effects on the transmission spectral characteristics of the solution-infiltrated MOF have been investigated. Owing to its highly sensitive light responsivity, ease of manipulation, and compactness, our proposed photosensitization approach for fiber-optic devices would have great promises for various related applications, such as light-intensity measurement and light-driven reconfigurable optical filtering. © 1989-2012 IEEE.

Zhou B.,Beihang University | Wang W.,Beijing Aerospace Control Instrument Research Institute
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2012

In strapdown inertial navigation system, the gyroscopes and accelerometers directly sense the carrier's angular motion, line movement and disturbance movement. When the centroid of three accelerometers does not coincide with the centroid of carrier, the impact of the carrier angular motion may cause the acceleration's measurement error. For high- and medium- precision SINS, the error of size effect can not be ignored and needs to be compensated when the carrier is in high dynamic situation. In this paper, the error model of the accelerometer size effect was derived, and a new integral expression for size effect error was proposed which was composed of the gyro output angle increment and the size effect parameters. Only by removing it from the accelerometer speed increment output, can we complete the compensation of the size effect error. The simulation shows that the Shula periodic oscillation amplitude of navigation system positioning error decreases significantly by using the new compensation algorithm, and the positioning precision has improved 5-6 times compared with that before compensation.

Zhou B.,Beihang University | Wang W.,Beijing Aerospace Control Instrument Research Institute
Applied Mechanics and Materials | Year: 2013

Through research on initial alignment problem of fiber optic gyro SINS in the sway condition, this paper proposed a rapid compass alignment scheme with variable parameters, which can accomplish rapid initial alignment. Firstly, analysted SINS compass alignment principle, and gave a concrete realization method which has the same calculation procedure with full damping navigation algorithm. This method makes the alignment and navigation to use the same set of algorithms, and can effectively reduce algorithm complexity. Simulation and repeatedly sway test results show that the alignment algorithm is effective. The alignment precision and instrument accuracy is consistent, it can meet the requirements of the initial alignment. © (2013) Trans Tech Publications, Switzerland.

Zhou B.,Beihang University | Wang W.,Beijing Aerospace Control Instrument Research Institute | He X.,Beijing Aerospace Control Instrument Research Institute
Beijing Hangkong Hangtian Daxue Xuebao/Journal of Beijing University of Aeronautics and Astronautics | Year: 2013

The impact of the gyro constant drift and accelerometer constant bias to the inertial navigation system (INS) can be reduced by rotation modulation technology, but the gyro random drift and noise can not be inhibited. The errors of INS will divergence under action of random disturbances, which affects the long-term ability to navigate. The damping technology to inhibit random error interference was concerned, and a damping rotating fiber optic gyro (FOG) inertial navigation system was presented. Using the damping technology the affect of random noise to navigation system accuracy was suppressed. Simulation results show that the single axis rotating FOG inertial navigation system precision is improved by more than one times with damping technology. When higher precision instrument is adopted, it will be more obvious for suppress effect of random error.

Qu J.,Harbin Institute of Technology | Guo W.,Harbin Institute of Technology | Wang Y.,Beijing Aerospace Control Instrument Research Institute
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology | Year: 2013

Friction material is one of the key components in an ultrasonic motor. The wear of the material affects the contact friction and output performance of the motor. A method which utilizes the equivalent wear of friction material to simulate the wear during operation is proposed based on the wear characteristics of the ultrasonic motor's contact interface. A relationship between wear and performances of the ultrasonic motor is constructed. The influences of wear on output performance, friction coefficient of the contact interface, and wear morphology are researched in the experiments. According to the experiment's results, with wear of friction material (decreasing thickness), the output performance of the ultrasonic motor presents a downward trend, the friction coefficient between contact interfaces decreases gradually, the friction-reducing ratio between contact interfaces increases gradually, and the wear between contact interfaces decreases. The results are helpful to understand operating performance, design, and select friction material of ultrasonic motor. © IMechE 2012.

Qu J.,Harbin Institute of Technology | Zhang Y.,Harbin Institute of Technology | Tian X.,Beijing Aerospace Control Instrument Research Institute | Guo W.,Harbin Institute of Technology
Tribology Letters | Year: 2014

While high friction coefficients and good wear resistance are antagonistic properties of most materials, these properties are expected to promote excellent torque-speed characteristics and extend the life span of ultrasonic motors. Blending is an accepted technique for modifying tribological applications. p-Hydroxybenzoic acid polymer (Ekonol) blends with different compositions, and proportions were prepared through mechanical blending. Poly(tetrafluoroethylene) (PTFE), poly(etheretherketone), and poly(phylenesulfide) (PPS) were selected as dispersed phases. The mechanical properties of the blends were investigated, and their tribological performance was tested using a block-on-ring wear meter. The worn surfaces of Ekonol blends were observed using a scanning electron microscope to elucidate the relevant wear mechanisms. Results showed that the dispersed phases have distinct effects on the impact strength and hardness, as well as friction coefficient and wear rate, of the blends. Curves of hardness and friction coefficient versus the dispersed phase content showed apparent similarities, which indicates that hardness influences the friction of polymer blends in contact with carbon steel. Worn tracks on the surfaces of different polymer materials showed that the dominant wear mechanism transforms from fatigue and abrasion into adhesion with the addition of a dispersed phase; delamination was observed in the transfer films, especially those formed by the Ekonol/PTFE and Ekonol/PPS blends. © 2014 Springer Science+Business Media.

Liu X.,Harbin Medical University | Jiang H.,Heilongjiang Province Hospital Nangang Branch | Lang Y.,Beijing Aerospace Control Instrument Research Institute | Wang H.,Harbin Institute of Technology | Sun N.,Harbin Medical University
Experimental and Therapeutic Medicine | Year: 2013

The present study proposed a novel projection display system based on a virtual reality enhancement environment. The proposed system displays stereoscopic images of fractures and enhances the computed tomography (CT) images. The diagnosis and treatment of fractures primarily depend on the post-processing of CT images. However, two-dimensional (2D) images do not show overlapping structures in fractures since they are displayed without visual depth and these structures are too small to be simultaneously observed by a group of clinicians. Stereoscopic displays may solve this problem and allow clinicians to obtain more information from CT images. Hardware with which to generate stereoscopic images was designed. This system utilized the conventional equipment found in meeting rooms. The off-axis algorithm was adopted to convert the CT images into stereo image pairs, which were used as the input for a stereo generator. The final stereoscopic images were displayed using a projection system. Several CT fracture images were imported into the system for comparison with traditional 2D CT images. The results showed that the proposed system aids clinicians in group discussions by producing large stereoscopic images. The results demonstrated that the enhanced stereoscopic CT images generated by the system appear clearer and smoother, such that the sizes, displacement and shapes of bone fragments are easier to assess. Certain fractures that were previously not visible on 2D CT images due to vision overlap became vividly evident in the stereo images. The proposed projection display system efficiently, economically and accurately displayed three-dimensional (3D) CT images. The system may help clinicians improve the diagnosis and treatment of fractures.

Qu J.,Harbin Institute of Technology | Zhang Y.,Harbin Institute of Technology | Tian X.,Beijing Aerospace Control Instrument Research Institute | Li J.,Harbin Institute of Technology
Wear | Year: 2015

Friction materials with favorable mechanical and tribological characteristics are critical to the drivability and reliability of ultrasonic motors. Preliminary screening at atmospheric conditions suggests that filled polymer composites such as poly-tetrafluoroethylene (PTFE), phenol formaldehyde resins (PF), and poly-p-hydroxybenzoic acid (Ekonol®) are potential candidates for use as friction materials ultrasonic motors. The wear behavior of these polymers in contact with duralumin (2A12) stators was examined and compared under various environmental conditions: room temperature (RT) and atmospheric pressure, RT and low vacuum (5Pa), RT and high vacuum (5×10-3Pa), and both low temperature and low vacuum. The wear loss of these various polymers was characterized by tracking changes in their surface roughness parameters (Ra and Rv). Wear tracks on the surfaces of different frictional materials were inspected using scanning electron microscopy. Results show that the wear resistance of Ekonol and PF composites is poorer in vacuum than in ambient conditions, whereas that of PTFE composite is not readily susceptible to ambient conditions. Lastly, wear modes and mechanisms at the various conditions are discussed. © 2014 Elsevier B.V.

Chen X.,Beijing Institute of Technology | Yang L.,Beijing Aerospace Control Instrument Research Institute | Li P.,Beijing Institute of Technology | Luo H.,Beijing Institute of Technology
Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument | Year: 2013

Any objects using an engine or moving objects will be charged because of a variety of different charging processes. It is possible to sense the object and its moving direction by measuring the electrostatic field around the object. In this paper, an electrostatic direction-finding system based on FPGA is designed to detect the direction of the charged moving object in real time. The system is composed of the electrostatic detection electrode array, current detecting electrostatic detection circuit and digital signal processing circuit based on FPGA. To meet the requirements of high input impedance and high sensitivity of the electrostatic signal detection circuit, the first and second stage amplifier circuits based on FET and operational amplifier were designed. According to the principle of electrostatic direction-finding, an electrostatic sensor calibration system was designed to calibrate the electrostatic sensors in the electrostatic direction-finding array, which insures the consistency of the electrostatic detection array and improves the direction-finding accuracy. The signal processor based on FPGA was designed according the performance parameters of the electrostatic direction-finding system, which achieves the signal acquisition and processing of the electrostatic sensors and the direction real time solution of the charged moving object. The experiment result shows that the direction angle error of the charged moving object using this system is less than 15° and the system meets the real-time solution requirements in certain extent.

Geng X.,Beijing Aerospace Control Instrument Research Institute | Geng X.,Tianjin University | Zhang F.-M.,Tianjin University
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2014

The color CCD and infrared filter are adopted to set up the measurement platform of high temperature forgings. The digital and physical filter technologies are applied to improve the quality of forging image and comparison measurement method is utilized to derive its two-dimensional size accurately. In order to calibrate the equivalent size of pixels in image, images of standard gauge blocks are captured and distortion calibration, noise suppression and sub-pixel edge detection are executed. As it is verified by other gauge blocks, the horizontal measurement uncertainty of the system is 0.0051 mm, while the vertical is 0.0087 mm. At 1000°C, image of 45# forging is captured and its dimension is calculated through the procedure, which has a difference less than 1 mm compared with the theoretical value, and meets the requirements of the precision.

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