tailieunhanh - Electrical Engineering Mechanical Systems Design Handbook Dorf CRC Press 2002819s_2

Tham khảo tài liệu 'electrical engineering mechanical systems design handbook dorf crc press 2002819s_2', kỹ thuật - công nghệ, điện - điện tử phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Extraction licthoaology Alternating Sums of tblume Volume Decomposition Graph-Based Recognition Knowledge-Based Recognita. User-lnteracttve Recognition Syntactic Pattern Recognition Recognition from CSG Recogntton fmm 2D Drawing Hybrid feature Recognition FIGURE Chronology of feature recognition work. 2002 by CRC Press LLC FIGURE Volume decomposition approach to feature recognition. Volume Decomposition Volume decomposition approaches seek to break up the A Volume into machining volumes. This process is illustrated in Figure . One of the most well-known approaches using volume decomposition is that adopted by Sakurai and Chin 1994 . In their approach the A Volume is decomposed by extending planar and curved faces of the part into minimal cells. These cells are recombined to form maximal volumes. By subtracting these volumes in different orders alternate volume decompositions can be generated. Tseng and Joshi 1994 have also adopted a similar decomposition process. One advantage of the approach adopted by Sakurai and Chin 1994 is that the definition and use of maximal volumes permit their algorithm to generate all feature interpretations. They argue that this provides an opportunity to find the optimal or near optimal feature interpretations Sakurai and Chin 1994 . This follows because their method is purely algorithmic as opposed to the more common heuristic approaches. One concern about their approach is that it is driven purely by the geometry of the part. Although this enables them to create a decomposition without having to specify a feature type and domain a priori it raises the question as to whether or not all maximal volumes generated can be mapped to a feature within a given domain in particular the machining domain. A second concern is whether their approach can be extended to surfaces which generate closed halfspaces quadrics for example. Alternating Sums of Volume A similar approach to volume decomposition first proposed by Woo