Please use this identifier to cite or link to this item: `http://hdl.handle.net/11455/1650`
DC FieldValueLanguage
dc.contributor.author歐星文zh_TW
dc.contributor.authorWen, Ou Hsinen_US
dc.date2000zh_TW
dc.date.accessioned2014-06-05T11:41:21Z-
dc.date.available2014-06-05T11:41:21Z-
dc.identifier.urihttp://hdl.handle.net/11455/1650-
dc.description.abstractThe purpose of this thesis is to develop a method to offset a NURBS(Non-Uniform Rational B-Spline) curve based on input error bound, and the offset curve should have the same format as the source curve. The designing of offset curves and surfaces is an essential task in CAD/CAM such as tool-path generation and pattern design. In previous work, offset curves are usually fitted with small straight lines or arc segments, and the continuity of the offsets reaches only zero or one. To obtain satisfying smooth offset curves, a large number of segments are required. For offset curves with NURBS format, it is easier to obtain curves with higher continuity and the required data memory is much less then using straight lines and arcs. The approach consists of following steps: (1) data points are sampled on source curve uniformly; (2) find tangent and normal vector of each sampling point; (3) find offset of sampling points with offset distance; (4) delete those offset points considered too close to one another; (5) use curve fitting method or control polygon based method to find the offset curve and to control the error of the curve using offset sampling points; (6) adjust the weights of control points of offset curve to reduce the error of the curve. At last, the advantages and disadvantages of each method and its influences on the change of errors are analyzed.en_US
dc.description.tableofcontents中文摘要 I 英文摘要 II 第一章、介紹 1 1.1 目的與方法 2 1.2 文獻回顧 3 1.3 內容大綱 7 第二章、NURBS之基本原理與常用演算法 8 2.1 NURBS曲線/曲面數學理論 8 2.1.1 Bezier曲線/曲面的定義 8 2.1.2 B-Spline曲線/曲面的定義 10 2.1.3 Bezier曲線/曲面的定義 14 2.2 節點插入法 16 2.3 節點消去法 19 2.4 權重與曲線外形的關係 23 第三章、偏置取樣點的取得 28 3.1 偏置位置的取得 28 3.2 幾何不連續處之消去 33 第四章、偏置曲線的產生 38 4.1 以擬合方式產生偏置曲線 38 4.1.1 使用插值法擬合曲線 39 4.1.2 使用近似法擬合曲線 41 4.1.3 曲線誤差之計算 43 4.1.4 以擬合方式產生偏置曲線 44 4.2 以控制點偏置求取偏置曲線 48 4.3 以權重的改變縮小偏置曲線的誤差 51 第五章、程式執行範例與應用 56 5.1 程式執行範例 56 5.2 曲線偏置之應用 70 第六章、結論與展望 73 參考文獻 Reference -Ⅰ-zh_TW
dc.language.isoen_USzh_TW
dc.publisher機械工程學系zh_TW
dc.subject誤差控制zh_TW
dc.subjectError controlen_US
dc.subjectNURBS曲線zh_TW
dc.subject偏置曲線zh_TW
dc.subjectNURBS curveen_US
dc.subjectOffset curveen_US
dc.subjectCurve fittingen_US
dc.subjectControl polygon based methoden_US
dc.title誤差控制之NURBS曲線偏置zh_TW
dc.titleError based NURBS Curve Offseten_US
dc.typeThesis and Dissertationzh_TW
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.openairetypeThesis and Dissertation-
item.cerifentitytypePublications-
item.fulltextno fulltext-
item.languageiso639-1en_US-
item.grantfulltextnone-
Appears in Collections:機械工程學系所

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