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Key technology of mine underground mobile positioning based on LiDAR and coded sequence pattern

中国有色金属学会会刊：英文版 2011年第S3期21卷 570-576页

作者： WANG Zhi1, 2. WU Li-xin1, 2. LI Hui-ying3.1. college of Resources and {2. Engineering, Northeastern university, Shenyang 110004,{3. 2. Academy of Disaster Reduction and Emergency Management, Ministry of {2. Affairs and Ministry of Education, beijing Normal university, beijing 100875,{3. 3. college of Computer Science and {12., Jilin university, Changchun 13.012.{3. [a] college of Resources and civil Engineering Northeastern University Shenyang 110004 China [b] Academy of Disaster Reduction and Emergency Management Ministry of Civil Affairs and Ministry of Education Beijing Normal University Beijing 100875 China [c] college of Computer Science and technology Jilin University Changchun 130012 China

Technologies of underground mobile positioning were proposed based on LiDAR data and coded sequence pattern landmarks for mine shafts and tunnels environment to meet the needs of fast and accurate positioning and navigation of equipments in the mine underground without satellite navigation signals. A coded sequence pattern was employed for automatic matching of 3. scans. The methods of SIFT feature, Otsu segmentation and fast hough transformation were described for the identification, positioning and interpretation of the coded sequence patterns, respectively. The POSIT model was presented for speeding up computation of the translation and rotation parameters of LiDAR point data, so as to achieve automatic 3. mapping of mine shafts and tunnels. The moving positioning experiment was applied to evaluating the accuracy of proposed pose estimation method from LiDAR scans and coded sequence pattern landmarks acquired in an indoor environment. The performance was evaluated using ground truth data of the indoor setting so as to measure derivations with six degrees of freedom.

关键词： LiDAR coded sequence pattern mobile positioning SLAM algorithm POSIT algorithm

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Analysis on cohesive crack opening displacement considering the strain softening effect

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Science china(Physics,mechanics & Astronomy) 2006年第1期49卷 88-101页

作者： WANG Limin1, XU Shilang2.& ZHAO Xiqiang3.1. mechanics Department, Shandong {2. of technology, Zibo 2.5049,{3. 2. civil Engineering Department, Dalian {2. of technology, Dalian 11602.,{3. 3. Mathematics Department, Ocean {2. of{3., Qingdao 2.6071,{3. mechanics Department Shandong University of Technology Zibo 255049 China civil Engineering Department Dalian University of Technology Dalian 116024 China Mathematics Department Ocean University of China Qingdao 266071 China

In order to investigate the crack propagation in quasi-brittle materials like rock, ceramic and concrete, Hillerborg and his co-researchers abstracted the fracture process zone in front of a stress free crack in terms of a “fictitious crack zone”. On the fictitious crack zone, cohesive stresses distribute following a given softening relationship of stress vs. crack opening. Based on the polynomial or power series expression of cohesive crack opening displacement, the relationship of the cohesive stress vs. the crack opening displacement is established using elastic theory and integral equation, and some unknown physics variables are obtained using variation approach. The calculation results gained in this paper are close to the experimentally test ones.

关键词： cohesive crack, softening, dissipation work, variation approach.

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Parameter identification theory of a complex model based on global optimization method

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Science china(Physics,mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2.& XU BingYe3.1 college of Automotive Engineering, South{2. university of {3., Guangzhou 510640,{2. 2.beijing Research Institute of Mechanical and Electrical {3., beijing 100083,{2. 3.Department of Engineering mechanics, Tsinghua university, beijing 100084,{2. 1. college of Automotive Engineering South China University of Technology Guangzhou 510640 China 2. beijing Research Institute of Mechanical and Electrical technology Beijing 100083 China 3. Department of Engineering mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 92.°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

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Numerical simulation of surface movement laws under different unconsolidated layers thickness

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中国有色金属学会会刊：英文版 2011年第S3期21卷 599-603页

作者： DAI Hua-yang1, LI Wen-chang2. LIU Yi-xin1,3. JIANG Yao-dong3.1. {2. of Geosicence and Surveying Engineering, china university of mining and technology, beijing 100083,{3. 2. {2. of Resources and Safety Engineering, china university of mining and technology, beijing 100083,{3. 3. {2. of {12. and civil Engineering, china university of mining and technology, beijing 100083,{3. [a] college of Geosicence and Surveying Engineering China University of Mining and Technology Beijing 100083 China [b] college of Resources and Safety Engineering China University of Mining and Technology Beijing 100083 China [c] college of mechanics and {2. Engineering China University of Mining and Technology Beijing 100083 China

Based on specific geology and mining conditions of certain coal working face in china, a series of numerical models under different unconsolidated layers thickness were respectively established by employing FLAC{2.. The relationship between the unconsolidated layers thickness and surface movement laws was studied. Maximum surface subsidence, Maximum horizontal displacement and surface subsidence degree were obtained. Contours of surface subsidence/horizontal displacement and curves were drawn. Some laws of surface subsidence/horizontal displacement were analyzed. The role of the unconsolidated layers in surface subsidence was revealed. It is significant to predict surface subsidence of thick unconsolidated layers for coal mine and take effective measures to control surface subsidence.

关键词： unconsolidated layers surface movement numerical simulation deep mining FLAC3.

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A class of discounted models for singular diffusion control

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Chinese Science Bulletin 2000年第5期45卷 405-408页

作者： LIU Kunhui, QIN Mingda & LU Chuanlai1. college of Sciences, Northern Jiaotong university, {2. 100044,{3. 2. Department of Mathematics and mechanics, {2. university of Science and technology, beijing 100083 .china 3. Department of Information Engineering, {2. university of Posts and Telecommunications, {2. 100876,{3. Correspondence should be addressed to Lu Chuanlai college of Sciences Northern Jiaotong University Beijing China Department of Mathematics and mechanics Beijing University of Science and Technology Beijing China Department of Information Engineering Beijing University of Posts and Telecommunications Beijing China

A kind of discounted problems for singular diffusion control have been studied. The drift and diffusion coefficients of state process are nonlinear. The class of models has been basically extended from a corresponding one established by Karatzes et al. before. By applying some analysis methods different from earlier works, the sufficient and necessary conditions of the existence of optimal control have been obtained. If an optimal control exists, it is a 'transient reflection' of state process for two lines.

关键词： stochastic control variational equation singular stochastic control.

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Decisive influence of the ionization strength of cosmic rays on the cavitation characteristics of pure water

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Science china(Technological Sciences) 2009年第6期52卷 1804-1808页

作者： CHANG JinShi college of Water Conservancy & civil Engineering,{2. Agricultural {3.,beijing 100083,{2. college of Water Conservancy & civil Engineering China Agricultural University Beijing 100083 China

The experiment result in this article shows that the initial and critical cavitation pressure of pure water are both increasing along with the increase of height above sea level,and the ionization strength of cosmic rays in the lower aerosphere is the crucial factor which influences the cavitation pressure of pure *** author concludes the relationship between the cavitaion pressure of pure water and the height above sea ***,air particles in water caused by the radiation of cosmic rays can exist in the water for a long time and will not escape.

关键词： initial cavitaiton pressure critical cavitation pressure ionization strength of cosmic rays height above sea level

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Mixed boundary conditions for piezoelectric plates

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Science china(Physics,mechanics & Astronomy) 2009年第5期52卷 755-761页

作者： GAO Yang 1 ,XU SiPeng 2.&ZHAO BaoSheng 3.1college of Science,{2. Agricultural university,{3. 100083,{2. 2.1} of Engineering,Ocean university of china,Qingdao 2.6071,{2. 3.School of Mechanical Engineering,university of Science and technology of Liaoning,Anshan 114044,{2. college of Science China Agricultural University Beijing 100083 China college of Engineering Ocean University of China Qingdao 266071 China School of Mechanical Engineering University of Science and Technology of Liaoning Anshan 114044 China

For plate bending and stretching problems in piezoelectric materials,the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate mixed boundary conditions accurate to all order.A decay analysis technique is used to establish necessary conditions that the prescribed data on the edge of the plate must satisfy in order that it should generate a decaying state within the *** the case of axisymmetric bending and stretching of a circular plate,these decaying state conditions are obtained explicitly for the first time when the mixed conditions are imposed on the plate *** are then used for the correct formulation of boundary conditions for the interior solution.

关键词： boundary conditions piezoelectric plates mixed data bending problems stretching problems

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Boundary conditions for the bending of a piezoelectric beam

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Science china(Physics,mechanics & Astronomy) 2008年第7期51卷 847-856页

作者： GAO Yang1, XU SiPeng2.& ZHAO BaoSheng3.1 college of Science,{2. Agricultural university,{3.,{2. 2.college of Engineering, Ocean university of{2., Qingdao 2.6071,{2. 3.School of Mechanical Engineering, university of Science and {12. Liaoning, Anshan 114044,{2. 1. college of Science China Agricultural University Beijing 100083 China 2. college of Engineering Ocean University of China Qingdao 266071 China 3. School of Mechanical Engineering University of Science and Technology Liaoning Anshan 114044 China

For beam bending in transversely isotropic piezoelectric media, the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the beam of general edge geometry and loadings. By generalizing the method developed by Gregory and Wan, a set of necessary conditions on the edge-data for the existence of a rapidly decaying solution is established. The prescribed edge-data of the beam must satisfy these conditions in order that they could generate a decaying state within the beam. When stress and mixed conditions are imposed on the beam edge, these decaying state conditions for the case of bending deformation of piezoelectric beam are derived explicitly. They are then used for the correct formulation of boundary conditions for the beam theory solution (or the interior solution). Besides, an analytical solution of elastic beam is formulated to verify validity of our boundary conditions. For the stress data, our boundary conditions coincide with those obtained in conventional forms of beam theories. More importantly, the appropriate boundary conditions with two sets of mixed edge-data are obtained for the first time.

关键词： boundary conditions beam bending piezoelectric media decaying states regular states

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The refined theory of deep rectangular beams based on general solutions of elasticity

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Science china(Physics,mechanics & Astronomy) 2006年第3期49卷 291-303页

作者： GAO Yang1 & WANG Minzhong2.1. college of Science, china Agricultural {2.,{3., china 2. State Key Laboratory for Turbulence and Complex Systems and Department of mechanics and Engi- neering Science, Peking {2., beijing 100871, china college of Science China Agricultural University Beijing 100083 China State Key Laboratory for Turbulence Complex Systems Department of mechanics Engineering Science Peking University Beijing 100871 China

The problem of deducing one-dimensional theory from two-dimensional the- ory for a homogeneous isotropic beam is investigated. Based on elasticity theory, the re- fined theory of rectangular beams is derived by using Papkovich-Neuber solution and Lur’e method without ad hoc assumptions. It is shown that the displacements and stresses of the beam can be represented by the angle of rotation and the deflection of the neutral surface. Based on the refined beam theory, the exact equations for the beam without transverse surface loadings are derived and consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beam under transverse loadings are derived directly from the refined beam theory and are almost the same as the governing equations of Timoshenko beam theory. In two ex- amples, it is shown that the new theory provides better results than Levinson’s beam the- ory when compared with those obtained from the linear theory of elasticity.

关键词： deep rectangular beams,the refined theory,Papkovich-Neuber solution,Lur'e method,governing equation

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The refined theory of transversely isotropic piezoelectric rectangular beams

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Science china(Physics,mechanics & Astronomy) 2006年第4期49卷 473-486页

作者： GAO Yang1 & WANG Minzhong2.1. college of Science, china Agricultural {2.,{3., china 2. State Key Laboratory for Turbulence and Complex Systems and Department of mechanics and Engi- neering Science, Peking {2., beijing 100871, china 1. college of Science China Agricultural University Beijing 100083 China 2. State Key Laboratory for Turbulence and Complex Systems and Department of mechanics and Engineering Science Peking University Beijing 100871 China

The problem of deducing one-dimensional theory from two-dimensional theory for a transversely isotropic piezoelectric rectangular beam is investigated. Based on the piezoelasticity theory, the refined theory of piezoelectric beams is derived by using the general solution of transversely isotropic piezoelasticity and Lur'e method without ad hoc assumptions. Based on the refined theory of piezoelectric beams, the exact equations for the beams without transverse surface loadings are derived, which consist of two governing differential equations: the fourth-order equation and the transcendental equation. The approximate equations for the beams under transverse loadings are derived directly from the refined beam theory. As a special case, the governing differential equations for transversely isotropic elastic beams are obtained from the corresponding equations of piezoelectric beams. To illustrate the application of the beam theory developed, a uniformly loaded and simply supported piezoelectric beam is examined.

关键词： rectangular beams, the refined theory, piezoelectric, transversely isotropic.

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