Point cloud based design and manufacturing

基于点云的设计和制造

• 批准号: 170374-2007
• 负责人: Spence, Allan
• 金额: $ 1.42万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=361779
• 关键词: Point; cloud; based; design; manufacturing

Conventional CAD/CAM software uses simple "CSG" block, etc. primitives combined with Boolean intersect, etc. operations to create 3-D models.  Sculptured B-spline curves and surfaces can be added, and "evaluated" to yield a topological set of "B-rep" bounded, volume enclosing surfaces.  In practice, the CSG to B-rep evaluation process involves inexact surface/surface intersections, and floating point round-off based exchange reliability problems remain.  Concurrently, stereo vision and laser triangulation systems, used to digitize design concept models, etc. into dense point clouds, have grown in acceptance.  These point clouds are converted to fitted B-spline surfaces and "faired" to smooth out curvature "bumps".  Use of B-splines reduces data storage requirements, and is compatible with the existing IGES/STEP exchange standards.     Ultimately, however, CAD models are converted back to point style representations.  Graphics hardware is based on rapid display of polygons that are created by "tesselating" from the B-rep model.  For manufacturing, Rapid Prototyping machines require STL triangle based file representations.  Ultimately, Computer Numerical Control (CNC) machining requires creation of tool paths that consist of (short) linear motions.  Their inherent reliability, combined with ever increasing computer speed and memory availability, has created a CAD research community trend away from CSG/B-rep and B-spline models to wholly point cloud representations.  The proposed research will harness this emerging trend, and extend early but successful applicant research from stereo vision and laser triagulation based sheet metal strain analysis to more general surface gray level and color measurement, point cloud based collision detection, and rapid prototype surface coloring using a 3-D Coordinate Measuring Machine (CMM) mounted inkjet printer head.  Additional potential applications include electrochemical etching for sheet metal and copper printed circuit boards, Computer Aided Tissue Engineering (CATE) by inkjet cell deposition, and haptic surgery planned using medical Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scan data.

传统的CAD/CAM软件使用简单的CSG块等基元结合布尔求交等操作来创建三维模型。可以添加和评估雕刻的B-Spline曲线和曲面，以产生有界的、体积封闭的曲面的拓扑集。但在实践中，CSG到B-rep的求值过程涉及不精确的曲面/曲面求交，基于浮点舍入的交换可靠性问题仍然存在。同时，立体视觉和激光三角测量系统，用于将设计概念模型等数字化为密集的点云，已经被越来越多的人接受。当这些点云被转换成拟合样条曲面并进行光顺以消除曲率的“凹凸”。B样条线的使用减少了数据存储需求，并且与现有的IGES/STEP交换标准兼容。然而，最终，CAD模型被转换回点样式表示。图形硬件是基于快速显示多边形的，这些多边形是通过从B-REP模型中“镶嵌”而创建的。对于制造来说，快速成型机需要基于STL三角形的文件表示。最终，计算机数字控制(CNC)加工需要创建由(短)直线运动组成的刀具路径。由于其固有的可靠性，再加上计算机速度和内存可用性的不断提高，已经形成了CAD研究社区的趋势，从CSG/B-rep和B-Spline模型到完全的点云表示。提出的研究将利用这一新兴趋势，并将早期但成功的应用研究从基于立体视觉和激光三重聚的板材应变分析扩展到更一般的表面灰度和颜色测量，基于点云的碰撞检测，以及使用安装在3D坐标测量机(CMM)上的喷墨打印头进行快速原型表面着色。其他潜在应用包括用于金属薄板和铜印刷电路板的电化学蚀刻、通过喷墨细胞沉积进行的计算机辅助组织工程(CATE)，以及使用医疗计算机断层扫描(CT)和磁共振成像(MRI)扫描数据计划的触觉手术。