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model reconstruction for worn blades based on hybrid surface registrations

Advances in Manufacturing 2022年第3期10卷 479-494页

作者： Kang Cui Rui-Song Jiang Lin Jing School of Automation and Software Engineering Shanxi UniversityTaiyuan 030006People's Republic of China School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065People's Republic of China

model reconstruction is crucial in blade repair because it directly determines the shape precision and finish of a repaired ***,owing to insufficient surface data pertaining to defective regions and the unique deformation caused by harsh environments,modeling a worn blade remains ***,a model reconstruction method for worn blades is developed in this *** conventional methods of constructing and interpolating sectional curves,the proposed method focuses on modifying a nominal computer aided design(CAD)model to reconstruct the worn *** weighted rigid registration and constraint-based non-rigid registration,the design surface extracted from the nominal CAD model can be deformed to align with the surface data of the worn blade without a significant loss of its initial *** results show that the deformed design surface exhibits sufficient smoothness and accuracy for guiding tool path generation in the subsequent blade repair.

关键词： Turbine blades Repair model reconstruction Registration

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A Medium/Long-Range Forecast of Pacific Subtropical High Based on Dynamic Statistic model reconstruction

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Acta meteorologica Sinica 2007年第3期21卷 376-384页

作者：洪梅张韧刘科峰余丹丹 Institute of Meteorology PLA University of Science and TechnologyNanjing 211101 LASGInstitute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 Institute of Meteorology PLA University of Science and TechnologyNanjing 211101

Based on the 500-hPa geopotential height field series of T106 numerical forecast products, by empirical orthogonal function （EOF） time-space separation, and on the hypotheses of EOF space-models being stable, the EOF time coefficient series were taken as dynamical statistic model variables. The dynamic system reconstruction idea and genetic algorithm were introduced to make the dynamical model parameters optimized, and a nonlinear dynamic statistic model of EOF separating time coefficient series was established. By the model time integral and EOF time-space reconstruction, a medium/long-range forecast of subtropical high was carried out. The results show that the dynamical model forecast and T106 numerical forecast were approximately similar in the short-range forecast （≤5 days）, but in the medium/long-range forecast （≥5 days）, the forecast results of dynamical model was superior to that of T106 numerical products. A new method and idea were presented for diagnosing and forecasting complicated weathers such as subtropical high, and showed a better application outlook.

关键词： dynamical statistic model reconstruction genetic algorithm empirical orthogonal function (EOF) subtropical high forecast

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model reconstruction FROM CLOUD DATA FOR RAPID PROTOTYPE MANUFACTURING

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Transactions of Nanjing University of Aeronautics and Astronautics 2001年第2期18卷 170-175页

作者：张丽艳周儒荣周来水南京航空航天大学CAD/CAM工程研究中心

model reconstruction from points scanned on existing physical objects is much important in a variety of situations such as reverse engineering for mechanical products, computer vision and recovery of biological shapes from two dimensional contours. With the development of measuring equipment, cloud points that contain more details of the object can be obtained conveniently. On the other hand, large quantity of sampled points brings difficulties to model reconstruction method. This paper first presents an algorithm to automatically reduce the number of cloud points under given tolerance. Triangle mesh surface from the simplified data set is reconstructed by the marching cubes algorithm. For various reasons, reconstructed mesh usually contains unwanted holes. An approach to create new triangles is proposed with optimized shape for covering the unexpected holes in triangle meshes. After hole filling, watertight triangle mesh can be directly output in STL format, which is widely used in rapid prototype manufacturing. Practical examples are included to demonstrate the method.

关键词： reverse engineering model reconstruction cloud data data filtering hole filling

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reconstruction of symmetric models composed of analytic curves and surfaces from point cloud

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1351-1362页

作者： Qing WANG Wei-dong ZHU Ying-lin KE State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

This paper presents a method to reconstruct symmetric geometric models from point cloud with inherent symmetric structure. Symmetry types commonly found in engineering parts, i.e., translational, reflectional and rotational symmetries are considered. The reconstruction problem is formulated as a constrained optimization, where the objective function is the sum of squared distances of points to the model, and constraints are enforced to keep geometric relationships in the model. First, the explicit representations of symmetric models are presented. Then, by using the concept of parameterized points (where the coor-dinate components are represented as functions rather than constants), the distances of points to symmetric models are deduced. With these distance functions, symmetry information, for both 2D and 3D models, is uniformly represented in the process of reconstruction. The constrained optimization problem is solved by a standard nonlinear optimization method. Owing to the explicit representation of symmetry information, the computational complexity of our method is reduced greatly. Finally, examples are given to demonstrate the application of the proposed method.

关键词： Reverse engineering model reconstruction Constrained optimization Symmetry

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A landslide monitoring method using data from unmanned aerial vehicle and terrestrial laser scanning with insufficient and inaccurate ground control points

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第10期16卷 4125-4140页

作者： Jiawen Zhou Nan Jiang Congjiang Li Haibo Li State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China College of Water Resources and Hydropower Sichuan UniversityChengdu610065China

Non-contact remote sensing techniques,such as terrestrial laser scanning(TLS)and unmanned aerial vehicle(UAV)photogrammetry,have been globally applied for landslide monitoring in high and steep mountainous *** techniques acquire terrain data and enable ground deformation ***,practical application of these technologies still faces many difficulties due to complex terrain,limited access and dense *** instance,monitoring high and steep slopes can obstruct the TLS sightline,and the accuracy of the UAV model may be compromised by absence of ground control points(GCPs).This paper proposes a TLS-and UAV-based method for monitoring landslide deformation in high mountain valleys using traditional real-time kinematics(RTK)-based control points(RCPs),low-precision TLS-based control points(TCPs)and assumed control points(ACPs)to achieve high-precision surface deformation analysis under obstructed vision and impassable *** effects of GCP accuracy,GCP quantity and automatic tie point(ATP)quantity on the accuracy of UAV modeling and surface deformation analysis were comprehensively *** results show that,the proposed method allows for the monitoring accuracy of landslides to exceed the accuracy of the GCPs themselves by adding additional low-accuracy *** proposed method was implemented for monitoring the Xinhua landslide in Baoxing County,China,and was validated against data from multiple sources.

关键词： Landslide monitoring Data fusion Terrestrial laser scanning(TLS) Unmanned aerial vehicle(UAV) model reconstruction

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Robust Parameter Estimation from Point Cloud Data with Noises for Augmented Reality 36

Robust Parameter Estimation from Point Cloud Data with Noise...

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第36届中国控制会议

作者： Yingzi Wei Tianhao Zhang Kanfeng Gu Zhengjin Shi Shenyang Ligong University School of Information Science and Engineering Shenyang Institute of Automation Chinese Academy of Science

ISBN: (纸本)9781538629185

Allowing for a priori optimization of the robot manipulation to improve the performance in the unmanned environment,it is critical for the augmented reality system to estimate the attitude of point clouds in model *** estimation of planar parameter is not always faithful for point cloud fitting,because the gross errors and outliers are not considered in by the traditional plane fitting *** attempt is to combine the random sample consensus and the least-squares method to detect and eliminate the outliers of point clouds for the plane *** 3D scanning system is applied for collecting the real data of point cloud from the planar *** the preprocessing,the point clouds are imported into OpenGL for the3 D model *** modeling process is depicted,*** comparative simulation experimental results between our method and the traditional methods,such as least-squares and eigenvalue method,are ***,our method is applied to the experiment of 3D laser scanning point cloud planes for the attitude *** method is validated on both simulated data and real *** results show that our method has better robustness and accuracy,especially for the point clouds containing various errors and outliers.

关键词： Point clouds Attitude estimation model reconstruction Augmented reality Random sample consensus

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