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    26 February 2016, Volume 37 Issue 1 Previous Issue    Next Issue

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    A Method for Pipe Auto Layout Based Improved RRT Algorithm
    Xu Lianjie, Liu Jianhua, He Yongxi, Wu Hongchao, Liu Jiashun
    2016, 37(1): 1-9.  DOI: 10.11996/JG.j.2095-302X.2016010001
    Abstract ( 136 )   PDF (1591KB) ( 337 )  
    An improved rapidly-exploring random tree algorithm is proposed based on collision
    information for the problem of non-orthogonal pipe automatic routing. This algorithm has three main
    improved methods: node expansion based collision information, fast bypassing obstacle algorithm
    and node expansion based on the thinking of node’s probability. It could search out a path to walk
    along the surface of structure parts in comparably short time. On the basis of the three methods, the
    optimization strategy based key nodes is used to optimize the obtained path and form the final result
    of pipe routing layout. A prototype system is developed and the feasibility of the algorithm by
    instance is verified.
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    Measurement Points Methods of Zooming Vanishing Point Triangle Based on Proportion or Reversing Coincidence View Point
    Wu Xuemei, Li Pingchuan, Wang Ying, Qian Xiaoming
    2016, 37(1): 11-13.  DOI: 10.11996/JG.j.2095-302X.2016010011
    Abstract ( 138 )   PDF (291KB) ( 216 )  
    The basic principles of measuring point method are more complex, and when drawing
    two-point perspective manually, the problem always occurred that vision point and vanishing points
    are out of the drawing board. A method is introduced with direct building facade method and assistant
    vanishing point. In order to effectively use drawing space, vanishing point triangles zoom according
    to the proportion or coincidence view point reverse. The advantage of the methods is to save vertical
    drawing space and perspective drawing is not too small. The practice have done to basic building. The
    methods are effective.
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    An Applicable and Efficient Algorithm for Carline Generation
    Zhu Bin, Jin Quandong, Wang Yantao
    2016, 37(1): 14-19.  DOI: 10.11996/JG.j.2095-302X.2016010014
    Abstract ( 93 )   PDF (1144KB) ( 228 )  
    The design and manufacturing of auto-body welding lines are important to production
    quality and efficiency of automobiles. Carlines are grid lines parallel to the axes of an auto-body
    coordinate system and used to position key components in the coordinate system. The carlines are
    used as datum references for the manufacturing and inspection of auto-bodies, so that they are of
    importance in guaranteeing manufacturing precision of auto-bodies. An algorithm is proposed for
    carline generation based on coordinate system transformation. At first, local coordinate systems are
    created. And then the revolution of jigs and their constituting parts is calculated and stored through
    the transformation between the local coordinate systems and the auto-body coordinate system. Finally,
    carlines are generated by projective transformation and marked automatically. In comparison to the
    traditional method, it can greatly improve the efficiency of carline generation as well as ensure the
    correctness of carlines. An automatic carline generation software module has been implemented and
    applied in the design of auto-body welding lines.
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    Clamping Sequence, Fixture Layout and Clamping Force on Machining Deformation and Synchronous Optimization Analysis
    Xu Xiaoyu, Zhao Xiaoci
    2016, 37(1): 20-24.  DOI: 10.11996/JG.j.2095-302X.2016010020
    Abstract ( 106 )   PDF (434KB) ( 253 )  
    In order to minimize the clamping deformation and improve the machining accuracy
    of thin-walled parts, a synchronous optimization method of clamping sequences, fixture layout and
    clamping forces was presented with the objective function of minimizing the deformation and through
    the combination of genetic algorithm and finite element method. An aviation thin-walled work piece
    was optimized by this method, and compared the optimization results with the experience empirical design
    and the traditional analysis results. This method can effectively reduce the work piece deformation due to
    improper clamping and improve the machining accuracy. The result proved the veracity of the
    synchronous optimization method of clamping sequences, fixture layout and clamping forces.
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    Branch Cable Automatic Routing Based on Co-evolutionary Algorithm
    Xu Jinbao, Liu Jianhua, Liu Jiashun, Liu Xiao
    2016, 37(1): 25-33.  DOI: 10.11996/JG.j.2095-302X.2016010025
    Abstract ( 122 )   PDF (2226KB) ( 249 )  
    Facing the problem that the middle forked point is difficult to determine which exists in the
    branch cable routing, a branch cable automatic routing method is proposed based on co-evolutionary
    algorithm. Firstly, the branch cable harness model is established. The approach divides the whole
    system of branch cable into a few single cables based on the cable harness model, and every single
    cable represents a population. Improved RRT (rapidly-exploring random trees, RRT) algorithm is
    used to obtain initial path of every single cable. Then middle forked points is optimized based on the
    idea of co-evolution, which is affected by other single cables during its evolution, and the branch
    cable routing optimized obtained. Finally, the final optimization of path points obtained were fitted to
    obtain the cable as a result. A 3D automatic routing prototype system is developed and some
    experiments are applied to verify the efficiency of the method.
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    Physical Characteristic Oriented Modeling for Flexible Cable Harness Based on Cosserat Elastic Rod Theory
    Lin Haili, Liu Jianhua, Tang Chengtong, Liu Jiashun
    2016, 37(1): 34-42.  DOI: 10.11996/JG.j.2095-302X.2016010034
    Abstract ( 239 )   PDF (2789KB) ( 369 )  
    To simulate laying process of cable harness, a physical characteristic oriented modeling for
    flexible cable harness is proposed based on Cosserat elastic rod theory. The cable’s total energy is
    obtained by applying Cosserat elastic rod theory on discrete cable model. The cable’s configuration
    with the lowest energy can be obtained by using optimization algorithm, which is the equilibrium
    state. The model takes into consideration the flexibility and continuity of the cable, which could
    simulate bending and twisting. From the discrete expression of the cable, the cable’s energy can be
    calculated by numerical method. And penalty method is used to convert the constraint problem to an
    unconstrained problem. The trust region algorithm is implemented to get the configuration of the
    cable with minimum potential energy. This method is applied in the simulation of cable laying
    process in a virtual environment and a prototype system is developed, and the model is validated by
    this system.
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    Research on Postprocessor of Five-Axis Machining Based on D-H Modified Method
    Qian Jing, Liu Zhibing, Wang Xibin, Yan Tao
    2016, 37(1): 43-48.  DOI: 10.11996/JG.j.2095-302X.2016010043
    Abstract ( 94 )   PDF (1030KB) ( 272 )  
    Transforming the CL data produced by CAD/CAM software into NC codes is needed in
    industrial areas. The application of D-H modified notation method in five-axis machine tools
    postprocessor development is studied. The process of parameter definition is described in D-H
    modified method and the improvement is put forward. A special postprocessor of DMU 80
    monoBlock five-axis machine tool is developed. At last, a simulation is made to verify the validity of
    the postprocessor by VERICUT. This program has some guiding significance in increasing the
    efficiency of data conversion in free-form surface five-axis machining.
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    The Process Optimization Strategy Based on Three-Dimensional Process Model Cut Load Dynamic Change
    Zhao Qian, Jiao Li, Tan Fanghao, Luo Zhiwen, Wang Xibin, Wang Zhao
    2016, 37(1): 49-55.  DOI: 10.11996/JG.j.2095-302X.2016010049
    Abstract ( 104 )   PDF (1555KB) ( 207 )  
    Integrating parts machining feature as well as constraints of various aspects, the right
    classification of typical surface groups is obtained by using of Boolean difference calculation. The surface
    groups is needed to generate typical process line spectrum for the sake of speeding up process design and
    optimization. According to the analysis of dynamic characteristics on the cut-part contact from the
    machining of difference three-dimensional process model typical surface groups, the dynamic cutting
    force prediction model of complex surface machining based on B-spline curves is used to analyze the
    changes of dynamic load, and effective control of cutting load is achieved through the optimization of
    cutting parameters. Finally, the turning of a part is carried out as a verification of the feasibility of the
    process optimization strategy.
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    On the Five Dimensions of Aesthetic Cognition of Airplane
    Gong Haoqin
    2016, 37(1): 56-59.  DOI: 10.11996/JG.j.2095-302X.2016010056
    Abstract ( 133 )   PDF (207KB) ( 264 )  
    Design of airplane goes hand in hand with aerodynamic character. The correspondence of
    its form and function pursuit leads to its unique aesthetic perception. The beauty of the airplane is
    aesthetic cognition of airplane, which is also the interpretation of the aerospace science and
    technology from the aspect of the aesthetic. Through the aesthetic analysis of the airplane function,
    shape, materials, technology, decoration and other aspects, it describes that the beauty of the airplanes
    is the combination of development of the science and technology and the aesthetic cognition in this
    essay. There are both the elegance of the aesthetic and the rationality of the technology in airplane,
    which indicate that industrial design will play a greater role in the aircraft exterior and interior design.
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    Extraction of Design Factors of Saline Soil Culture Based on Visual Correlation Analysis
    Wang Weiwei, Liu Yin, Wang Yi
    2016, 37(1): 60-65.  DOI: 10.11996/JG.j.2095-302X.2016010060
    Abstract ( 119 )   PDF (3691KB) ( 336 )  
    A creative product design idea of saline soil cultural is proposed that can make its spirit
    heritage to excavate and protect saline soil culture. Through the research on revolution brought by
    three salt ancestors during the development, the involving artifacts were analyzed. Action verbs and
    other modern design methods were integrated into the extraction of characteristic factors. Using eye
    movement test for visual correlation analysis and combining with emotional engineering method to
    evaluate the extracted programs, the selected design factors were applied to the product design. This
    process has achieved good results that can be seen in serial tea set design. The connotation of the
    product has enhanced. The attractiveness of saline soil culture has increased.
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    Using Bag of Visual Words for Video Retrieval Calibration
    Wu Lianliang, Cai Hongming, Jiang Lihong
    2016, 37(1): 66-73.  DOI: 10.11996/JG.j.2095-302X.2016010066
    Abstract ( 96 )   PDF (2622KB) ( 567 )  
    With the rapid development of Internet technology, the number of videos is proliferating in
    an exploding way. The traditional text-based retrieval method may bring problems of content missing
    and semantic gap, and result in lower retrieval relevance score. Therefore, a video retrieval calibration
    method is proposed, which is based on bag of visual words and combines the visual features
    extraction technology, TF-IDF technology and the open data technology. First, the HSV-based
    clustering algorithm is used to extract the video key frames and the weight vector. Second, speed up
    robust features and some other visual features are used to resolve video content missing problem.
    Third, the TF-IDF technology is used to measure the weight of keyword, and the open data
    technology to obtain the visual features and semantic of the query word, then solve the semantic gap
    problem. Finally, our video retrieval calibration algorithm is applied on the Internet Archive data set.
    The result shows that compared with traditional text-based video retrieval method, our method has a
    15% relative improvement on the average retrieval relevance score.
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    Accelerated Multimodal Images Joint Non-local Filtering
    Yang Yuanqin, Wei Ning, Dong Fangmin
    2016, 37(1): 74-78.  DOI: 10.11996/JG.j.2095-302X.2016010074
    Abstract ( 94 )   PDF (685KB) ( 266 )  
    In this paper, a novel non-local averaging based multimodal image filtering method is
    provided. In the method, the mean average for filtering the noisy image is computed non-locally and
    weights for average is jointly guided by the reference image taken from another imaging device. The
    experiment results show that the proposed method is better than state of the art joint bilateral filter,
    especially in the case of the periodic texture is involved in the images. Furthermore, an acceleration
    algorithm is proposed by constructing integral histograms, speeding up by factor of about 2 order
    compared with the brute-force method. In addition, the algorithm is independent of the size of the
    filter, and easy to be implemented on parallel system.
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    A Correcting Method Based on Header and Footer Line for Warped Documnet Images
    Zeng Fanfeng, Duan Yangbo
    2016, 37(1): 79-83.  DOI: 10.11996/JG.j.2095-302X.2016010079
    Abstract ( 96 )   PDF (6613KB) ( 360 )  
    The recognition rate of OCR (optical character recognition) is low because of the warped
    document images. For those warped document images with header and footer lines, a fast method is
    proposed to increase the rate of OCR in this paper. Firstly, the location of the header line is detected
    and restored in the document image. Then the distance of the line moving upward or downward is
    calculated based on geometric algorithm. After that, the image is scanned using the distance as
    parameters and the distance that every target pixel needs to remove is calculated. At the same time, all
    pixel are removed in order to restructure the image and then a well corrected image is obtained.
    Experiments demonstrated that this correcting method was efficient. The OCR rate of warped
    document image with header line could be significantly improved.
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    Classification of the Detail Features for Clothes Based on HOG and Geometric Features
    Ji Juan, Qin Ke, Yang Ruoyu
    2016, 37(1): 84-90.  DOI: 10.11996/JG.j.2095-302X.2016010084
    Abstract ( 142 )   PDF (5123KB) ( 584 )  
    Due to the increased demand for the diversification of clothing products, clothes
    classification is very necessary, no matter for operators or consumers. Existing methods usually solve
    the problem based on the whole clothes, paying little attention to the detail features on the clothes.
    Therefore, identifying and classifying the detail features of clothes are emphasized in this paper such
    as the type of collar, the length of sleeves and the trousers or the dresses. Based on the contour
    extraction, the paper proposes the voting strategy for the results gained from multi-scale HOG
    features. Also the geometric features are used based on corner detection, solving problems like collar
    position uncertainty, neckline shape interference caused by surrounding patterns and so on. Then,
    SVM classifier is used to get the final results. After that, some advice is also provided on costume
    matching using multiple coefficient matrixes of features matching. Experiments show that our method
    is effective for classifying some mentioned detail features. Also, it shows some practical value for the
    automatic matching recommendation.
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    Big Data Image Segmentation Based on Multi-exemplar Affinity Propagation
    Xu Xiaoli
    2016, 37(1): 91-96.  DOI: 10.11996/JG.j.2095-302X.2016010091
    Abstract ( 83 )   PDF (876KB) ( 303 )  
    Based on multi-exemplar affinity propagation clustering, a fast segmentation algorithm is
    proposed for big data images. The proposed algorithm preprocesses an input big data image by mean
    shift algorithm to form segmented regions that preserve the desirable discontinuity characteristics of
    images. The numbers of segmented regions, instead of the numbers of image pixels, are considered as
    the input data scale of multi-exemplar affinity propagation clustering algorithm. The average of the
    color vectors in each region is calculated and considered as an input data point of multi-exemplar
    affinity propagation clustering algorithm. Euclidean distances between regions are regards as
    similarity measure index, and then the multi-exemplar affinity propagation clustering algorithm is
    applied to perform globally optimized clustering and segmentation based on similarity matrix.
    Experimental results illustrate that the proposed algorithm has superior performance and less
    computational costs compared for big data image segmentation.
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    Key Technology of 3D Virtual Maintenance Training System
    Ma Tian, Li Hongan, Ma Benyuan, Kang Baosheng
    2016, 37(1): 97-101.  DOI: 10.11996/JG.j.2095-302X.2016010097
    Abstract ( 81 )   PDF (1969KB) ( 268 )  
    In order to solve the problem of complex operation in 3D virtual maintenance training, a
    general data format of disassembly and assembly relation was proposed, and the data processing
    method was realized, which could be used to customize training application for various equipments
    easily. A simple and efficient disassembly operation method was presented, which has automatic shaft
    alignment constraint, and a 2D screen space dragger was designed and realized based on that. A 3D
    virtual maintenance training simulation system was developed, and the virtual scene was rendered and
    managed through OpenSceneGraph (OSG) engine, which architecture and scene organization were
    analyzed. The disassembly operation record and report output were realized. The application results
    show that this system has good performance on real-time and 3D display effect.
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    Real-Time and Dynamic Clothes Simulation of Different Fabric Materials
    Xue Yuan, Huang Luchen, Yang Ruoyu
    2016, 37(1): 102-109.  DOI: 10.11996/JG.j.2095-302X.2016010102
    Abstract ( 124 )   PDF (681KB) ( 352 )  
    A parametric method for 3D human modeling is proposed in this paper. A set of feature
    parameters are defined to control the topological structure of human body comprising ten parts.
    Zhang spline is then used to construct the human surface of each part. Real-time garment dressing
    simulation is implemented based on the integrated human model. As an improvement of traditional
    mass-spring method, large-span bend spring is proposed for the purpose of wrinkle simulation.
    Furthermore, proper setting of parameters along with multistep correction strategy enables simulation
    of different fabric materials, namely cotton, silk and elasticity. The experimental results show that our
    system can construct relatively realistic human model as well as realize complete and flexible
    garment dressing simulation in real time.
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    A Method of Positioning and Posture Perceiving Based on the Virtual-Real Roaming System
    Zhao Haiying, Chen Hong, Mu Xiaofeng
    2016, 37(1): 110-114.  DOI: 10.11996/JG.j.2095-302X.2016010110
    Abstract ( 100 )   PDF (3782KB) ( 300 )  
    The paper focuses on the integration of GPS positioning technology with the emerging
    intelligent mobile terminal, realizing the function of cell phone GPS extension and highlighting the
    unique advantage in the aspect of ruins displaying. The following is the specific method, firstly,
    establish the region mapping of virtual scene and real scene through the data conversion; then bind
    the camera angle and handheld devices by using the gyroscope and set up posture mapping between
    virtual character and reality role; finally achieve the virtual-real roaming through plugin package
    Unity3D. The method breaks the limitation of time and space, enriches the information content and
    the interestingness of works, and provides a personalized browse mode of cultural heritage scenes. It
    could be applied on some ruins’ scenes such as Yuanmingyuan Imperial Garden.
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    Research and Implementation of Visual Management System Based on Quest3D
    Feng Guizhen, Zhang Zengqiang, Chi Jianbin, Xing Haijun
    2016, 37(1): 115-119.  DOI: 10.11996/JG.j.2095-302X.2016010115
    Abstract ( 80 )   PDF (6061KB) ( 354 )  
    As a platform of 3D interactive technology based on DirectX, Quest3D has very good
    application space. By taking a project as an example and structuring with VC++, Quest3D and
    MySQL, a visual management system based on studying the process, method and related technology
    of constructing 3D interactive virtual scene with Quest3D is developed, which achieves data
    synchronization and updates through service monitoring mechanism. In the virtual engineering
    projection scene, users can interactively manipulate and freely walk with mouse or keyboard, search
    projection message, visually warn existed problems and the preplan of emergency event handling and
    so on, provideing visual solution for the engineering construction and project management.
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    An Improved Method for Engineering Drawing Animation of PowerPoint
    Luo Nianmeng, Dong Tianlin, Deng Xiaojie
    2016, 37(1): 120-124.  DOI: 10.11996/JG.j.2095-302X.2016010120
    Abstract ( 102 )   PDF (849KB) ( 259 )  
    Animation in PowerPoint has a major position in the current teaching of engineering
    drawing, but making and modifying animation are difficult in the PowerPoint. A method of
    combining AutoCAD vector graphic to make animation is put forward, and the problem of graphic
    drawing and animation remodification is solved well.
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    Accurate Methods of Printing Figures with AutoCAD Format Embedded in Scientific and Technological Documents
    Jing Tianhu, Ma Xiaolong, Liu Junli, Mo Shixu
    2016, 37(1): 125-139.  DOI: 10.11996/JG.j.2095-302X.2016010125
    Abstract ( 190 )   PDF (487KB) ( 264 )  
    It is significant to accurately print out text height, line width and drawing scales of figures
    in textbooks on engineering drawing and courseware. In order to precisely print illustrations in these
    documents, features of displaying figures, line width of drawing objects, and character height in
    drawings are studied from several concepts about plotting based on analysis of the making course of
    drawings by means of AutoCAD software embedded in scientific and technological documents whose
    components of pages are predominantly words and characters. The study shows that preliminary
    dimensions of figures measured by Word software should be regarded as physical paper size of
    drawings and canvas for painting, and printing scale of drawings and properties of line weight and
    height of text characters in drawings ought to be exactly set, by which accurate drawings up to the
    national standards about engineering drawings in documents can be printed out.
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    Analysis of Dynamic Characteristic of a Pipelayer Crane System
    Song Qiuhong, Wang Haohui, Xu Shaorong, Yang Shaojie
    2016, 37(1): 130-138.  DOI: 10.11996/JG.j.2095-302X.2016010130
    Abstract ( 50 )   PDF (5053KB) ( 254 )  
    Pipelayer is a kind of engineering machinery, which is used in the pipe laying and lifting
    operation, and it would create a dangerous swing sharply under the external incentives. This can not
    only reduce the lifting precision, but also cause collisions between hanging objects and structures. So
    it has great importance for safety of pipelayer operation to analysis its system dynamic characteristic,
    control and predict shimmy. First the article describes the working environment of pipelayer, then
    proposes summary and comparison of relevant research of domestic and foreign. In this paper, the
    mathematical model of hanging objects is established, and MATLAB is used to do data analysis. The
    result shows that length of the sling, external excitation, landing speedcan lead to a great impact on
    the dynamic response, shimmy frequency and angel of inner and outer surfaces.
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    Overtake of Pedestrian Based on Geometrical Method in Evacuation Process
    He Dazhi, Li Ping, Zhang Qianhan
    2016, 37(1): 139-142.  DOI: 10.11996/JG.j.2095-302X.2016010139
    Abstract ( 69 )   PDF (378KB) ( 221 )  
    Overtake is a very important character of pedestrian. When people move to the destination,
    they can watch the circumstances around themselves, and chose a better direction to move, rather than
    turning around until they collide with other evacuee. The paper propose an effective method based on
    geometrical algorithm. In this method, the each pace moving of a pedestrian is divided into three
    steps. The first step is to define the vision region, and four important sight lines and three vision
    regions. The second step is to counter the numbers of evacuee in each region, and compare the
    density of evacuee in each region and chose the minimal one. The last step is to decide the direction
    in the chosen region. Experimental results demonstrate the reality of the method.
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