Browsing by Author "PERNG, DB"

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AUTOMATIC 3D MACHINING FEATURE-EXTRACTION FROM 3D CSG SOLID INPUT
(1990-06-01)
PERNG, DB
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CHEN, Z
;
LI, RK
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交大名義發表
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資訊科學與工程研究所
AUTOMATIC CONSISTENCY VERIFICATION OF MECHANICAL CAD FILES
(1993-07-01)
PERNG, DB
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CHEN, Z
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WU, JS
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資訊科學與工程研究所
;
工業工程與管理學系
A system for automatic verification of the exactness of the CAD files of a mechanical part with planar and cylindrical faces through 3D part reconstruction is described. A set of consistency checking rules are specified to facilitate the part reconstruction. The system not only reconstructs the 3D geometry from a correct drawing file, but also produces adequate error messages to aid the designer to make corrections. We shall present our method with illustrations. Experimental results indicate that the set of checking rules is very useful and the system is very effective.
AUTOMATIC FORM FEATURE RECOGNITION AND 3D PART RECONSTRUCTION FROM 2D CAD DATA
(1994-10-01)
LIU, CH
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PERNG, DB
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CHENZ
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資訊科學與工程研究所
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工業工程與管理學系
In this paper, a method which can recognize form features and reconstruct 3D part from 2D CAD data automatically is proposed. First, we use the divide-and-conquer strategy to extract the vertex-edge data from each 2D engineering drawing of IGES format. Then, a set of production rules are developed to facilitate the form feature matching process. A new structure of form feature adjacency graph (FFAG) is devised to record the related attributes of each form feature. Finally, to avoid the combinatorial subparts-composition problem, a sweeping operation and volumetric intersection approach is used to rapidly reconstruct the remaining 3D object. The last reconstructed 3D object is used as the base of the FFAG. All the recognized form features in the FFAG can be classified as depression or protrusion features on the 3D part base. The FFAG structure can be easily transformed into CSG/DSG structure, which is readily integrated with the downstream CAPP/CAM systems. A detailed example is provided to illustrate the feasibility and effectiveness of the proposed system.
AUTOMATIC RECONSTRUCTION OF 3D SOLID OBJECTS FROM 2D ORTHOGRAPHIC VIEWS
(1988)
CHEN, Z
;
PERNG, DB
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
FAST RECONSTRUCTION OF 3D-MECHANICAL PARTS FROM 2D-ORTHOGRAPHIC VIEWS WITH RULES
(1992-01-01)
CHEN, Z
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PERNG, DB
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CHEN, CJ
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WU, CS
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資訊科學與工程研究所
A fast algorithm for 3D part reconstruction from a 3-view drawing is presented. A set of rules are specified to facilitate the part reconstruction. The main idea is to use the rules to determine the truth or falsity of 3D faces and the coexistence or non-coexistence relationships between 3D faces. In a graph search formulation of the reconstruction problem, these rules can reduce remarkably (a) the graph search space, (b) the occurrence of backtracking in the search and (c) the branching factor of the tree expansion. We shall present our method with illustrations. Currently we limit the type of part to be plane-faced for presentation simplicity, although we are extending our method to cover the cylindrical parts, too. Experimental results indicate the set of rules is useful and our reconstruction method is very effective.
FEATURE-BASED PROCESS PLAN GENERATION FROM 3D DSG INPUTS
(1994-07-01)
PERNG, DB
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CHENG, CT
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交大名義發表
;
工業工程與管理學系
;
National Chiao Tung University
A method that can automatically generate a process plan from 3D input data for a prismatic part is proposed. The 3D input data are the machining features represented in the DSG tree model [1]. A DSG tree is a special case of CSG tree in which all geometric operations are of difference type. The proposed method can (a) transfer the DSG-represented input data into refined machinable features, (b) determine the machinability of features, and (c) determine the cutting directions of all features of a prismatic part. This information is used to determine the machines, tools, and machining sequences that are required to manufacture a part. The NC paths are also generated. Computer simulations are provided to illustrate the proposed method. The major contribution of this paper is that the process plan of a CSG represented prismatic part can be generated automatically through the proposed method. It, therefore, extends the application domain of the CSG tree model and fully integrates CAD/CAM systems.