Measurement of a highly freeform surface using a cylindrical null-screen

2021 ◽  
Author(s):  
Oliver Huerta-Carranza ◽  
Manuel Campos-García ◽  
Daniel Aguirre-Aguirre ◽  
Brenda Villalobos-Mendoza ◽  
Victor Ivan Moreno-Oliva
Keyword(s):  
Author(s):  
Feifei Chen ◽  
Yunpeng Miao ◽  
Guoying Gu ◽  
Xiangyang Zhu

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 663
Author(s):  
Hui Zhang ◽  
Dengfei Liu ◽  
Yinwan Wei ◽  
Hong Wang

We propose a design method of asymmetric double freeform surface lens for an integrated LED automobile headlamp and develop an integrated LED automobile optical system. A single asymmetric double freeform surface lens is designed to redistribute rays emitting from the light source for realizing both low and high beams. Moreover, a freeform surface reflector is used to improve the energy efficiency of high beams. The prism placed in the optical path can suppress chromatic dispersion on the edge of the target plane. Simulation and experimental results show that the illumination values and color temperature of the key points can fully meet the requirements of United Nations Economic Commission for Europe vehicle regulations (ECE) R112, 48, and 128. The volume of the whole optical system comprised of freeform surface elements is smaller than that of the low beam system of a traditional headlamp, resulting in saved space, in which other electronic devices can be installed for the safety of the driver, which indicates that the proposed method is practical in the field of automobile lighting.


2018 ◽  
Vol 57 (17) ◽  
pp. 4743 ◽  
Author(s):  
Qun Hao ◽  
Shaopu Wang ◽  
Yao Hu ◽  
Yifeng Tan ◽  
Tengfei Li ◽  
...  

Author(s):  
H. James de St. Germain ◽  
David E. Johnson ◽  
Elaine Cohen

Reverse engineering (RE) is the process of defining and instantiating a model based on the measurements taken from an exemplar object. Traditional RE is costly, requiring extensive time from a domain expert using calipers and/or coordinate measurement machines to create new design drawings/CAD models. Increasingly RE is becoming more automated via the use of mechanized sensing devices and general purpose surface fitting software. This work demonstrates the ability to reverse-engineer parts by combining feature-based techniques with freeform surface fitting to produce more accurate and appropriate CAD models than previously possible.


Author(s):  
Haichao Wang ◽  
Jie Zhang ◽  
Xiaolong Zhang ◽  
Changwei Ren ◽  
Xiaoxi Wang ◽  
...  

Feature recognition is an important technology of computer-aided design/computer-aided engineering/computer-aided process planning/computer-aided manufacturing integration in cast-then-machined part manufacturing. Graph-based approach is one of the most popular feature recognition methods; however, it cannot still solve concave-convex mixed interacting feature recognition problem, which is a common problem in feature recognition of cast-then-machined parts. In this study, an oriented feature extraction and recognition approach is proposed for concave-convex mixed interacting features. The method first extracts predefined features directionally according to the rules generated from attributed adjacency graphs–based feature library and peels off them from part model layer by layer. Sub-features in an interacting feature are associated via hints and organized as a feature tree. The time cost is reduced to less than [Formula: see text] by eliminating subgraph isomorphism and matching operations. Oriented feature extraction and recognition approach recognizes non-freeform-surface features directionally regardless of the part structure. Hence, its application scope can be extended to multiple kinds of non-freeform-surface parts by customizing. Based on our findings, implementations on prismatic, plate, fork, axlebox, linkage, and cast-then-machined parts prove that the proposed approach is applicable on non-freeform-surface parts and effectively recognize concave-convex mixed interacting feature in various mechanical parts.


2010 ◽  
Vol 37-38 ◽  
pp. 1327-1331
Author(s):  
Qi Tong Liu ◽  
Jian Ming Zhan ◽  
Jian Hua Mao

An adaptive tool system of polishing robots for large freeform surface which is installed discoid tool is proposed. To improve processing efficiency, the mechanical of adaptive tool system adjust to curvature changing of large freeform surface is designed. Adaptability of the processing is analyzed and simulated, and kinematic equation of tool system is established. The polishing process of large freeform surfaces with tool system is analyzed.


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