Wu H.,North China Electrical Power University |
Wu Y.,China Institute of Technology |
Liu C.,North China Electrical Power University |
Yang G.,North China Electrical Power University |
Li Z.,China North Industries Corporation
Chinese Journal of Electronics | Year: 2016
This paper presents a novel approach to the initialization of an ego-motion estimation technique for autonomous power line inspection. Dual channel vision, consisting of an infrared and optical camera, is typically adopted during inspection. The infrared camera is far more proficient at reliably detecting heated regions of the power tower which can be regarded as a prior relationship between the tower and cameras. Using the infrared camera, which is equipped parallel to the optical camera, an incomplete correspondence between the optical image and a 3D CAD model is established. Depending on the degree of correspondence, the initial pose of the CAD model in the optical image is estimated through two stages of coarse-to-fine estimation. The primary contributions of this paper include: 1) using dual vision for partial initialization; 2) incorporating two-stage algorithms to estimate an accurate pose quickly; 3) implementing an algorithm which functions correctly regardless of the motion blur or background texture. Experimental results consistently show that the initial pose can be estimated efficiently and robustly. © 2016 Chinese Institute of Electronics.
Wang D.,Beijing Institute of Technology |
Hao Q.,Beijing Institute of Technology |
Song Y.,Beijing Institute of Technology |
Cheng X.,Tsinghua University |
And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016
In our previous works, we presented a zoom system and image stabilization design based on deformable mirrors (DMs). According to the high bandwidth and free edge characteristics of the piezoelectric deformable mirror (PDM), we tested the system's image-stable capability. We found the PDM could realize some tilt displacements while keeping a certain stable surface shape, it could obtain higher image stabilizing precision when integrated with the traditional mechanical image stabilization systems. In the design of the image stabilization system, the PDM's tilt displacement range is a key factor for consideration. So in this paper, we carried out a tilt displacement range testing experiment by using the OKO's 37-channel PDM. We measured and analyzed the variation of the tilt displacements in optical image stabilization process, and calculated the maximum tilt angle as the PDM surface shape was stabilized. We built an experimental platform consisting of a fixed target, an imaging system based on PDM, and a CCD camera. We used the ZYGO interferometer as an evaluation instrument to measure the surface shape stability. When the PDM surface had a tilt displacement, the image point of the fixed target on the camera sensor shifted correspondingly. The tilt angle of the PDM could be obtained by calculating this shift. The results showed that the maximum tilt angle of the PDM was 0.2mrad. The paper also analyzed the experiment errors when concerning about the off-axis error of the PDM deflection center. © 2016 SPIE.
Yang R.-J.,Nanjing University of Science and Technology |
Yang H.,China North Industries Corporation |
Liang X.-D.,North Heavy Industries Group Corporation Ltd. |
Wang L.-M.,Nanjing University of Science and Technology
Dandao Xuebao/Journal of Ballistics | Year: 2012
To enhance the large-space combat capability for guided projectile(GP), a robust adaptive controller for GP was proposed by combining a parameter estimation scheme with the sliding mode control. Considering the aerodynamic parameter symmetry and cross coupling characteristics of GP, a parametric sliding mode controller was obtained via feedback linearization. The parametric adaptation law was designed based on Lyapunov stability theory, and the adaptive sliding mode controller had strong robustness. Simulation results indicate that the proposed controller is robust with respect to large aerodynamic parametric uncertainty, and has excellent dynamic tracking performance with no control chattering.
Liang F.,Southwest Jiaotong University |
Li F.H.,Southwest Jiaotong University |
Zhang Y.W.,Hebei Hydrology and Engineering Geology Prospecting Institute |
Cui S.A.,Southwest Jiaotong University |
Li J.L.,China North Industries Ltd
Applied Mechanics and Materials | Year: 2013
Based on thermodynamic principles,this paper uses ANSYS to simulate thermal stress of the concrete piers and analyzes the main factors, namely, structure size, concrete strength, boundary conditions and freeze-thaw cycle system which affect thermal stress. We then draw the conclusion that the existence of thermal stress will make the concrete structure undertake cracking risk. Thermal stress difference in massive concrete structures is large and the influence of thermal stress on concrete structures is only limited to a certain size range; thermal stress inside the concrete increases with the increment of concrete strength grade; thermal stress inside the concrete decreases with the increment of boundary constraint conditions; the rate of change of thermal stress increases with the acceleration of freeze-thaw cycles. Meanwhile, we propose that through increasing the thickness of the protective layer and boundary constraint conditions properly, cracking risk of concrete structures can be reduced. © (2013) Trans Tech Publications, Switzerland.
Yang Q.,Beijing Institute of Technology |
Yang Q.,North China Electrical Power University |
Wang M.,Beijing Institute of Technology |
Wang M.,North China Electrical Power University |
Yang H.,China North Industries Corporation
Chinese Control Conference, CCC | Year: 2013
Some existing map-matching algorithms have some defects in the robustness and working in real-time. However, the computational geometry algorithms only use the non-numerical methods which make it easy and fast to get the results. But the existing algorithms based on computational geometry can't work in the situation that the main roads and the side roads are paralleled to each other. To solve the problems mentioned above, a map matching algorithm based on graphics is proposed in this paper. The algorithm proposed in this paper utilizes the method which is used to determine whether the segment is intersected with the polygons in graphics to determine the candidate road set. And in the process of getting the match road, if the current position is not in the only confidence region of the candidate roads, the algorithm gets the match road by checking if the position property (the current position is in which side of the road) has changed for more than 3 times. If so, the road is chosen as the match road. By doing this, the algorithm can choose the candidate road set and match the vehicle to the roads effectively. Through real car tests, the correct matching rate is no less than 95% and the time for single point matching is no more than 0.9 ms. © 2013 TCCT, CAA.
Liu H.-O.,Beijing Institute of Technology |
Jin L.,Beijing Institute of Technology |
Chen J.-B.,China North Industries Corporation
Journal of Beijing Institute of Technology (English Edition) | Year: 2016
In order to improve the shift decision strategy for an off-road vehicle with automated manual transmission (AMT), the generalized road resistance coefficient is defined based on the longitudinal dynamics analysis. Vehicle mass and generalized road resistance coefficient are estimated using the recursive least square (RLS) method with multiple forgetting factors. The improved shift schedule is designed based on the generalized road resistance coefficient under uphill road condition. The simulation and real vehicle test verify the effectiveness of improved shift strategy and the improvement of vehicle dynamic performance. © 2016 Beijing Institute of Technology.
Wang J.,Beijing Institute of Technology |
Lin W.,China North Industries Corporation |
Wang P.,Beijing Institute of Technology |
Liu M.,Beijing Institute of Technology |
Wang W.,Beijing Institute of Technology
Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering | Year: 2011
A precise, controllable and repeatable test conditions was provided by the hardware-in-the-loop simulation technology for guiding missile. According to the work characteristics of laser guided weapon simulation system, the impact of laser energy chain on the accuracy of hardware-in-the-loop simulation was analyzed. The major factors that affect the property of the laser energy were analyzed, including the weather factors, the reflection characteristics of targets and the distance between the missile and target, etc. And the theoretical model and calculation method were given. According to the actual power density for the seeker, laser energy chain were studied which provided a theoretical foundation for the hardware- in-the-loop simulation system.
Cao B.,Nanjing University of Science and Technology |
Wang H.,Nanjing University of Science and Technology |
Wang Y.,Nanjing University of Science and Technology |
Huang D.,Nanjing University of Science and Technology |
And 2 more authors.
2014 Asia-Pacific Microwave Conference Proceedings, APMC 2014 | Year: 2015
In this paper, a W-band high gain L-probe feed low temperature co-fired ceramic (LTCC) antenna array with a laminated waveguide (LWG) cavity is presented. The LWG cavity reduces the losses caused by severe surface wave at this band. Moreover, the L-probe is deployed to drive the antenna for high gain. In addition, a low-loss LWG feed network is applied to antenna array design. The simulated results show that the gain of antenna element is more than 7 dBi from 90 GHz to 100 GHz, and the maximum is 8.3 dBi. The 1×4 antenna array is designed with a gain up to 14 dBi by reconfiguring radiating elements and feeding network. Copyright 2014 IEICE.
Yang D.-M.,Southwest University of Science and Technology |
Wang Q.-L.,Southwest University of Science and Technology |
Ji H.-X.,Southwest University of Science and Technology |
Xie L.-M.,Southwest University of Science and Technology |
And 2 more authors.
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition) | Year: 2012
The γ-LiAlO 2:Tb 3+phosphor was synthesized by citric acid sol-gel method, and its excitation and emission spectra was investigated. γ-LiAlO 2:Tb 3+has several emission peaks, and these are located at 489, 542, 584 and 620 nm, which correspond to the 5D 4→ 7F J, (J=6, 5, 4, 3) transitions of Tb 3+, respectively. The main peak is at 542 nm. The strongest excitation peak at 238 nm of the powder(monitored at an emission wavelength of 542 nm) belongs to the broadband excitation. The effect of amount of Tb 3+ doping content, the charge compensation agent(Li +) on the emission intensity of the γ-LiAlO 2:Tb 3+phosphor were also studied. The results showed that the emission intensity can be controlled by the above factors, and the intensity can be enhanced by selecting the prime optimum conditions.
Yang Z.-P.,University of Science and Technology of China |
Wu Y.-H.,China North Industries Corporation |
Bian Q.-Q.,Mianyang Normal University
Gongneng Cailiao/Journal of Functional Materials | Year: 2013
Modified polyolefin microporous membrane was prepared as the separator for Li-ion batteries by surface radiation coating of methoxy poly (ethylene oxide) acrylate ester. The modified membrane can be well wetted by liquid electrolyte. The ion conductivity of the membrane is easily achieved by absorbing the liquid electrolyte due to the high amphoteric character surface. With the modified membrane as a separator, the graphite/cathode cell exhibited a good capacity retention. It is also found that the Li-ion cell fabricated in this manner not only has stable capacity retention, but also show good high-rate performance.