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Accurate Evaluation of Free-form surface Profile Error Based on Quasi Particle Swarm Optimization Algorithm and surface subdivision

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Chinese Journal of Mechanical Engineering 2013年第2期26卷 406-413页

作者： WEN Xiulan ZHAO Yibing WANG Dongxia ZHU Xiaochun XUE Xiaoqiang Automation Department Nanjing Institute of Technology

Although significant progress has been made in precision machining of free-form surfaces recently, inspection of such surfaces remains a difficult problem. In order to solve the problem that no specific standards for the verification of free-form surface profile are available, the profile parameters of free-form surface are proposed by referring to ISO standards regarding form tolerances and considering its complexity and non-rotational symmetry. Non-uniform rational basis spline（NURBS） for describing free-form surface is formulated. Crucial issues in surface inspection and profile error verification are localization between the design coordinate system（DCS） and measurement coordinate system（MCS） for searching the closest points on the design model corresponding to measured points. A quasi particle swarm optimization（QPSO） is proposed to search the transformation parameters to implement localization between DCS and MCS. surface subdivide method which does the searching in a recursively reduced range of the parameters u and v of the NURBS design model is developed to find the closest points. In order to verify the effectiveness of the proposed methods, the design model is generated by NURBS and the measurement data of simulation example are generated by transforming the design model to arbitrary position and orientation, and the parts are machined based on the design model and are measured on CMM. The profile errors of simulation example and actual parts are calculated by the proposed method. The results verify that the evaluation precision of freeform surface profile error by the proposed method is higher 10%-22% than that by CMM software. The proposed method deals with the hard problem that it has a lower precision in profile error evaluation of free-form surface.

关键词： profile error evaluation free-form surface quasi particle swarm optimization surface subdivision

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维普期刊数据库

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A novel method for sculptured surface subdivision

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Computer Aided Drafting,Design and Manufacturing 2012年第1期22卷 15-19页

作者： You Sikun Liu Xiaochu Deng Hongguang Liu Jun Department of Mechanical Engineering School of Mechanical and ElectricGuangzhou UniversityGuangzhou 510006China

In this work, a novel method for sculptured surface subdivision to improve the machinery＇s ability and efficiency in 5-axis CNC machining complex surface is introduced. The method subdivides automatically a monolithic convex or concave or simultaneously complex sculptured surface into a number of surface patches and achieves the goal of similar normal directions and small difference between the curvatures in every patch by using weight fuzzy cluster algorithm which takes the curvatures and normal vectors of the sculptured surface into account simultaneously. The inclination angle variation between every two Cutter Contact Points （CC Points） is decreased in every patch to avoid large-angle rotation of tool to save machining time when a flat-end mill is used. This work contributes to automating 5-axis CNC tool path generation for sculptured part machining and forming a foundation for further research.

关键词： 5-axis fuzzy cluster curvature and normal direction surface subdivision

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维普期刊数据库

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Adaptive triangular mesh coarsening with centroidal Voronoi tessellations

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第4期10卷 535-545页

作者： Zhen-yu SHU Guo-zhao WANG Chen-shi DONG Institute of Computer Graphics and lmage Processing Department of Mathematics Zhejiang University Hangzhou 310027 China Laboratory of Information and Optimization Technologies Ningbo Institute of Technology Zhejiang University Ningbo 315100 China

We present a novel algorithm for adaptive triangular mesh coarsening. The algorithm has two stages. First, the input triangular mesh is refined by iteratively applying the adaptive subdivision operator that performs a so-called red-green split. Second, the refined mesh is simplified by a clustering algorithm based on centroidal Voronoi tessellations (CVTs). The accuracy and good quality of the output triangular mesh are achieved by combining adaptive subdivision and the CVTs technique. Test results showed the mesh coarsening scheme to be robust and effective. Examples are shown that validate the method.

关键词： Triangular mesh Mesh coarsening surface subdivision Centroidal Voronoi tessellations (CVTs)

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维普期刊数据库

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Implementation of Triangle subdivision for Holding Sharp Features with Flatness Control

Implementation of Triangle Subdivision for Holding Sharp Fea...

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2011 International Conference on Computer Science and Information Technology(ICCSIT 2011)

作者： Wei Liu Lizhu Wang Lina Xu Faculty of Materials and Energy Guangdong University of technology

ISBN: (纸本)9781612848334

In this paper we introduce a improved rule for the well-known Loop subdivision that can keep the sharp shape of the object, in addition, we put forward a approach named flatness control to control how quickly the control points in an neighborhood converge towards the tangent plane which will obtain a more complicated surface. In order to get the required model, in the first step, we compute the position using the improved rules and modify it with flatness control in the second step.

关键词： surface subdivision Loop subdivision sharp features flatness control

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