基于Voronoi图的复杂曲面加工刀具轨迹规划
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摘要
刀具轨迹规划算法是数控加工的核心技术,是多轴联动机床数控加工的重要基础。本文针对复杂曲面直接偏置法生成环形刀轨时经常出现轮廓局部自交与全局自交问题,将Voronoi图理论应用于平面多连通域环切刀具轨迹规划中。首先,分析了平面多连通域特点,提出了一种适合于多连通域Voronoi图的分治波阵面传播算法,该算法首先将多连通域看成若干单连通域的组合,采用波阵面传播算法构造各单连通域,即构建外轮廓和孤岛Voronoi图,然后将这些Voronoi图进行缝合,缝合线包括内外轮廓Voronoi图的缝合以及内轮廓相互之间Voronoi图的缝合。之后,基于构建的Voronoi图进行加工区域划分,然后在各小区域即区内保持偏置量一致的条件下依次对各边界轮廓作偏置来生成环形刀具轨迹,为使刀具轨迹满足实际加工的需要,对环间最优切削行距进行了分析和规划。最后,以核电站水室封头零件的外表面粗加工为例,验证了算法的有效性。本研究不仅为具有多连通域特点的复杂零件加工提供刀具轨迹规划算法,同时也为进一步开发数控软件提供技术支持。
Tool-path generation algorithm is the core technolgy of the automatic programming software and it is also the important basis for numerical control maching.As the traditional offset method is of low efficiency and often cause local and overall intersection,the Voronoi diagram is used for tool-path generation for multiply connected domain.First,partition and wavefront algorithm is empolied for multiply connected domain based on the feature analysis of multiply connected domain,in the new approach,the multiply connected domain is considered as a composition of each domain,each domain is constructed with partition and wavefront method,so the Voronoi diagram is build for outer line and isolated island,then all the voronoi diagram are sewed,the machining area is divided,the offset approach is used for tool path generation for each area with the condition that the offset value is the same for each outer line.Then the gap between each contour is analyzed and optimized to meet the needs of actual maching.Finally,the algrithm is tested for the rough maching of water cabinet cover of a nuclear power station.This new approach can not only be used for complicated part maching with multiply connected domain,but also can provide a technacal support for the development of numerical control system software.
Tool-path generation algorithm is the core technolgy of the automatic programming software and it is also the important basis for numerical control maching.As the traditional offset method is of low efficiency and often cause local and overall intersection,the Voronoi diagram is used for tool-path generation for multiply connected domain.First,partition and wavefront algorithm is empolied for multiply connected domain based on the feature analysis of multiply connected domain,in the new approach,the multiply connected domain is considered as a composition of each domain,each domain is constructed with partition and wavefront method,so the Voronoi diagram is build for outer line and isolated island,then all the voronoi diagram are sewed,the machining area is divided,the offset approach is used for tool path generation for each area with the condition that the offset value is the same for each outer line.Then the gap between each contour is analyzed and optimized to meet the needs of actual maching.Finally,the algrithm is tested for the rough maching of water cabinet cover of a nuclear power station.This new approach can not only be used for complicated part maching with multiply connected domain,but also can provide a technacal support for the development of numerical control system software.
引文
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[13]陈剑虹,马鹏举,田杰谟,等.基于Voronoi图的快速成型扫描路径生成算法研究[J].机械科学与技术,2003,22(5):728-731.CHEN J H,MA P J,TIAN J M,et al.Scanning path algorithm for rapid prototyping(RP)based on Voronoi diagrams[J]Mechanical Science and Technology.2003,22(5):728-731.
[14]付庄,王树国,王剑英.多连通域Voronoi图生成算法的研究[J].系统工程与电子技术,2000,22(11):88-90.FU Z,WANG S G,WANG J Y.An algorithm of Voronoi diagram generation for multiply connected polygonal domains[J].Systems Engineering and Electronics,2000,22(11):88-90.
[15]杨工明,陈言秋,黄松波.Voronoi图的描述和平分线单调性的研究[J].计算机辅助工程,2000(4):31-39.YANG G M,CHEN Y Q,HUANG S B.The description of Voronoi diagram and the monotone of Vononoi bisectors[J].Computer Aided Engineering,2000(4):31-39.
[16]郑铁豹,王新生.一种有Voronoi剖分约束的启发式穿越算法,燕山大学学报,2012,36(4):348-352.ZHENG T B,WANG X S.A heuristic traversing algorithm with constrainted Voronoi division[J].Journal of Yanshan University,2012,36(4):348-352.
[2]KIM H C,LEE S H,YANG D Y.Toolpath planning algorithm for the ablation process using energy sources[J].Computer-Aided Design,2009,41(1):59-64.
[3]PARK S C.Sculptured surface machining using triangular mesh slicing[J].Computer-Aided Design,2004,36(3):279-288.
[4]刘壮,张德强,周来水,等.自由曲面三轴粗加工刀具轨迹的计算方法[J].南京航空航天大学学报,1997,29(2):131-137.LIU Z,ZHANG D Q,ZHOU L S,et al.3-axis machining algorithn for multi-surfaces[J].Journal of Nanjing University of Aeronautics&Astronautics,1997,29(2):131-137.
[5]黄常标,江开勇,林俊义.平面型腔平行双向刀具轨迹的优化生成[J].制造业自动化,2005,27(6):28-30.HUANG C B,JIANG K Y,LIN J Y.Optimal generation of parallel bidirectional tool path in planar cavity[J].Manufacturing Automation,2005,27(6):28-30.
[6]KIM B H,CHOI B K.Machining efficiency comparison directionparallel tool path with contour-parallel tool path[J].Computer-Aided Design,2002,34(2):89-95.
[7]LEE E.Contour offset approach to spiral toolpath generation with constant scallop height[J].Computer-Aided Design,2003,35(6):511-518.
[8]詹阳烈.型腔高速切削加工的刀具轨迹规划方法研究[D].上海:上海交通大学,2009:17-44.ZHAN Y L.The research toolpath generation method for high speed machinine of pocket[D].Shanghai:Shanghai Jiao Tong University,2009:17-44.
[9]PERSSON H.NC machining of arbitrarily shaped pockets[J].Computer-Aided Design,1978,10(3):169-174.
[10]LEE D T.Medial axis transformation of a planar shape[J].IEEETransactions on Pattern Analysis and Machine Intelligence,1982,4(4):363-369.
[11]STEVEN F.A sweepline algorithm for Voronoi diagrams[J].Algorithmioa,1987,2(1):153-174.
[12]HELD M.Voronoi diagrams and offset curves of curvilinear polygons[J].Computer-Aided Design,1998,30(4):287-300.
[13]陈剑虹,马鹏举,田杰谟,等.基于Voronoi图的快速成型扫描路径生成算法研究[J].机械科学与技术,2003,22(5):728-731.CHEN J H,MA P J,TIAN J M,et al.Scanning path algorithm for rapid prototyping(RP)based on Voronoi diagrams[J]Mechanical Science and Technology.2003,22(5):728-731.
[14]付庄,王树国,王剑英.多连通域Voronoi图生成算法的研究[J].系统工程与电子技术,2000,22(11):88-90.FU Z,WANG S G,WANG J Y.An algorithm of Voronoi diagram generation for multiply connected polygonal domains[J].Systems Engineering and Electronics,2000,22(11):88-90.
[15]杨工明,陈言秋,黄松波.Voronoi图的描述和平分线单调性的研究[J].计算机辅助工程,2000(4):31-39.YANG G M,CHEN Y Q,HUANG S B.The description of Voronoi diagram and the monotone of Vononoi bisectors[J].Computer Aided Engineering,2000(4):31-39.
[16]郑铁豹,王新生.一种有Voronoi剖分约束的启发式穿越算法,燕山大学学报,2012,36(4):348-352.ZHENG T B,WANG X S.A heuristic traversing algorithm with constrainted Voronoi division[J].Journal of Yanshan University,2012,36(4):348-352.