Optimal Layout of Three-Dimensional Coordinate Measurement System Based on Laser Multi-Lateration

2014 ◽  
Vol 41 (7) ◽  
pp. 0708001
Author(s):  
胡进忠 Hu Jinzhong ◽  
余晓芬 Yu Xiaofen ◽  
任兴 Ren Xing ◽  
赵达 Zhao Da
Keyword(s):  
Measurement System ◽  
Three Dimensional ◽  
Optimal Layout ◽  
Coordinate Measurement ◽  
Three Dimensional Coordinate

Research on the influence of background light on the accuracy of a three-dimensional coordinate measurement system based on dual-PSD

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaohong Lu ◽  
Yu Zhou ◽  
Jinhui Qiao ◽  
Yihan Luan ◽  
Yongquan Wang
Keyword(s):  
Neural Network ◽  
Measurement System ◽  
Bp Neural Network ◽  
Measurement Accuracy ◽  
Three Dimensional ◽  
Electrical Method ◽  
Content Type ◽  
Coordinate Measurement ◽  
Background Light ◽  
Three Dimensional Coordinate

Purpose The purpose of this paper is to analyze the measurement error of a three-dimensional coordinate measurement system based on dual-position-sensitive detector (PSD) under different background light. Design/methodology/approach The mind evolutionary algorithm (MEA)-back propagation (BP) neural network is used to predict the three-dimensional coordinates of the points, and the influence of the background light on the measurement accuracy of the three-dimensional coordinates based on PSD is obtained. Findings The influence of the background light on the measurement accuracy of the system is quantitatively calculated. The background light has a significant influence on the prediction accuracy of the three-dimensional coordinate measurement system. The optical method, electrical method and photoelectric compensation method are proposed to improve the measurement accuracy. Originality/value BP neural network based on MEA is applied to the coordinate prediction of the three-dimensional coordinate measurement system based on dual-PSD, and the influence of background light on the measurement accuracy is quantitatively analyzed.

Layout Optimization of Three-Dimensional Coordinate Measurement System Based on Laser Multi-Lateration

2014 ◽  
Vol 41 (1) ◽  
pp. 0108006
Author(s):  
胡进忠 Hu Jinzhong ◽  
余晓芬 Yu Xiaofen ◽  
彭鹏 Peng Peng ◽  
黄开辉 Huang Kaihui
Keyword(s):  
Measurement System ◽  
Three Dimensional ◽  
Layout Optimization ◽  
Coordinate Measurement ◽  
Three Dimensional Coordinate

scholarly journals High-NA fiber point-diffraction interferometer for three-dimensional coordinate measurement

2014 ◽  
Vol 22 (21) ◽  
pp. 25550 ◽  
Author(s):  
Daodang Wang ◽  
Xixi Chen ◽  
Yangbo Xu ◽  
Fumin Wang ◽  
Ming Kong ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Coordinate Measurement ◽  
Three Dimensional Coordinate

CFD Performance Evaluation and Runner Blades Design Optimization in a Francis Turbine

2009 ◽  
Author(s):  
Jose Manuel Franco-Nava ◽  
Erik Rosado-Tamariz ◽  
Oscar Dorantes-Gomez ◽  
Jose´ Manuel Ferna´ndez-Da´vila ◽  
Reynaldo Rangel-Espinosa
Keyword(s):  
Measurement System ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Francis Turbine ◽  
Computational Domain ◽  
Coordinate Measurement ◽  
Spiral Case ◽  
Hydraulic Turbines ◽  
Optimization Methodology ◽  
Artificial Neural Network Ann

The application of computational fluid dynamics (CFD) in the redesign or rehabilitation of hydraulic turbines appears to be necessary in order to improve their efficiency and cost-effectiveness beyond the traditional redesign practices. The runner geometry considered within the computational domain was modelled by using a three-dimensional laser triangulation scanner coupled with a portable coordinate measurement system. The runner geometry was generated by a number of 3D sub models, one for each of the main components of the runner, crown, band and a blade. In order to obtain a blade geometry a portable coordinate measurement system based on optical digitalization technology (scanner technology) was used. A numerical optimization methodology is developed and applied to a Francis turbine. The hydrodynamic performance analysis was investigated by application of a three dimensional Navier-Stoke commercial turbomachinery oriented CFD code. Analysis of the flow through the spiral case and stay vanes was carried out so as to include appropriate flow effects induced by these components and boundary conditions at the inlet of the wicket. A CFD analysis for the wicket and runner was carried out to generate the so called reference solution. Then, the runner blades design was optimized by a process implemented in a commercial CFD code which combines genetic algorithms and a trained artificial neural network (ANN). A database of geometries and their respective CFD computations were computed in order to determine the optimum geometry for a given objective function. The flow within hydraulic turbines has a thin boundary layer and noticeable pressure gradients. Hence, the CFD computations were carried out using the Sparlat-Allmaras turbulence model. After optimization cycle convergence, an increment not only in efficiency but also in power was obtained. The optimized runner represented by a parametric model achieves considerably higher efficiency than the reference runner. Efficiency versus power curve was used to compare data from measurements at the power station for the reference runner versus the parametric optimized runner model. Results have shown that application of CFD based optimization can modify and improve runners design so as to increase the efficiency and power of installed hydraulic power stations.

Three-Dimensional Coordinate Measurement with Point-Diffraction Interferometer Based on Levenbery-Marquardt Algorithm

2014 ◽  
Vol 34 (8) ◽  
pp. 0812001
Author(s):  
王道档 Wang Daodang ◽  
王福民 Wang Fumin ◽  
陈茜茜 Chen Xixi ◽  
孔明 Kong Ming ◽  
赵军 Zhao Jun
Keyword(s):  
Three Dimensional ◽  
Coordinate Measurement ◽  
Marquardt Algorithm ◽  
Three Dimensional Coordinate
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