【作者】 钟山；

【导师】 杨永强；

【作者基本信息】 华南理工大学 ， 机械电子工程， 2013， 博士

【摘要】 随着人们审美观念的变化和制造水平的不断提高，个性化且具有复杂曲面的零件日益广泛地应用于生产和生活中，另外全球的市场竞争要求缩短设计制造周期，因此探索复杂曲面的快速设计制造技术十分必要。增材制造AM（Additive Manufacturing）在加工复杂曲面方面具有明显优势，正向设计FD（Forward Design）和逆向设计RD（ReverseDesign）两种模式都可以提供复杂曲面增材制造所需的CAD模型，其建模快速性与精确性各有特点。本文主要研究复杂曲面的正向/逆向快速设计的关键技术，此外基于正向/逆向设计的CAD模型，提出复杂曲面增材制造的三种数据处理方法。据此，论文研究的主要内容与成果如下：（1）面向复杂曲面的增材制造，为了提高设计速度和精度，解决NURBS复杂曲面正向快速设计的关键问题，提出一种NURBS曲面局部特征重用方法。首先提出特征形状的识别和提取算法；然后制定局部特征安装的规则与方法，完成形状局部特征的复制粘贴；最后采用过渡曲面拼接算法，实现相邻NURBS曲面满足G2连续的光滑拼接。仿真结果显示，重用后特征具有良好的几何性。（2）面向复杂曲面的增材制造，从保证设计的快速性和精确性出发，为解决STL复杂曲面逆向快速设计的关键问题，建立基于延拓逼近的曲线曲面数学模型。首先建立基于延拓逼近的曲线重构数学模型；其次提出基于延拓逼近的STL曲面重构算法，较好地保证STL曲面重构的连续性和光顺性；最后对平面凸轮轮廓曲线和汽车保险杠曲面进行重构实验，验证延拓逼近曲线曲面重构算法的快速性和精确性。（3）针对正向快速设计得到的NURBS复杂曲面，为了提高成形精度与效率，提出一种面向增材制造的多策略自适应分层综合算法。首先提出切线角和毗邻分层面积变化综合判定算法去决定分层厚度；其次为保证后续数控加工的插补速度恒定和加工精度，提出基于Clothoid曲线模型的水平层面曲线轮廓重构算法。加工实例证明，自适应综合算法的分层效率高，成形后得到的复杂曲面制品具有良好加工精度。（4）针对逆向快速设计得到的STL复杂曲面，从提高成形精度与效率出发，提出一种面向增材制造的优化分层处理算法。首先为了优化水平分层厚度，在自适应切片中提出逐步细化的分层算法；然后采用延拓逼近算法去重构水平轮廓曲线；其次提出基于层片布尔运算支撑区域的识别算法。最后以加工实例验证算法的适用性和精确性。（5）基于逆向快速设计得到的空间点云模型曲面零件，为了提高成形精度与效率，提出面向增材制造的IDS（Inverse Distance Square）自适应直接分层算法。首先提出空间点云数据直接切片的新思路；然后提出IDS自适应直接分层算法，分层精度更高；其次在垂直切片投影构造面的曲线轮廓重构中，建立基于点云的延拓外推模型；最后采用角度误差法和弓高误差法，完成曲线重构与轮廓数据点的均化和精整处理。加工实例验证算法高精度和高效率。更多还原

【Abstract】 With people’s aesthetic concepts changing and the manufacture process standardimproved, individuated products of complicated surfaces are used increasingly in productionand daily lives. On the other hand, competitions in the global product market require themanufacture industry shortens the design and manufacture cycle. Therefore, it is verynecessary to research the rapid design and manufacture technology of complicated surfacedproducts. Additive Manufacturing owns an obvious advantage in respect of processingproducts of complicated surfaces. Forward Design and Reverse Design are capable of helpingprovide Additive Manufacturing for complicated surfaces with suitable CAD models. Thispaper is aimed at the research on the crucial technology of rapid Forward/Reverse Design forcomplicated-surfaced products. Besides, based on CAD models of Forward/Reverse Design,three data processing methods of Additive Manufacturing for complicated surfaces areproposed. According to what is mentioned above, the main content and results of this paperare as follows.（1）Additive Manufacturing for complicated surfaces. For the sake of improving,thedesign speed and accuracy and solving the crucial problems on rapid Forward Design ofproducts of complicated NURBS surfaces, a reuse method of partial features of NURBSsurfaces is proposed. First of all, the recognition and extraction algorithm of feature shapes isproposed. Secondly, the principals and methods of partial feature installation are drawn up.Afterwards, copy and paste of partial shape features are finished. Finally, the joint andconstruction algorithm of transition surfaces is proposed in order that continuous and smoothjoint satisfying G2between two adjacent NURBS surfaces is realized. It is shown inaccordance with the simulation result that reused features have good geometric properties.（2）Additive Manufacturing for complicated surfaces. For the purpose to guaranteedesign rapidity and accuracy and solve the crucial problems on Rapid Forward Design ofproducts of complicated STL surfaces, mathematic models for The Extended Approximationof curves and surfaces are set up. Above all, mathematic models of curve reconstruction basedon The Extended Approximation are established. Then STL surface reconstruction algorithmbased on The Extended Approximation is presented, which is able to well ensure continuityand smoothness of STL surface reconstruction. Finally, the reconstruction experiment onoutline curves of plane cams and surfaces of bumpers is carried out to test and verifyspeediness and the precision of the Extended Approximation algorithm.（3）Aimed at rapid Forward Designed products of NURBS complicated surfaces and in the way of increasing shaping accuracy and efficiency, a comprehensive algorithm ofmulti-strategied adaptive slicing for Additive Manufacturing is presented. Firstly, it is raisedthat slice thickness depends comprehensively on contingence angles of the points in verticalprofile curves and the area changes of adjacent slices. Plus, horizontal slice outline curvereconstruction algorithm based on Clothoid curve models is proposed by way of making surethat interpolation speed of follow-up numerical control machining is constant. It is proved bypractical processing examples that slicing efficiency of the comprehensive adaptive algorithmis higher and after being shaped, complicated-surfaced products owns great fabricatingaccuracy.（4）Aimed at rapid Reversed Designed products of STL complicated surfaces, aslice-optimizing processing algorithm for Additive Manufacturing is proposed for the purposeto increase shaping accuracy and efficiency. For the first part, a stepwise refined slicingalgorithm in adaptive slices is proposed so that horizontal slice thickness can be optimized. Inaddition, the horizontal outline curves are reconstructed by means of the The ExtendedApproximation algorithm. Again, the recognition algorithm of supporting regions based onslice Boolean operation is proposed. In the end, feasibility and precision of this algorithm aretested and verified by practical fabricating examples.（5）Surfaced products of dimensional point cloud models based on rapid ReverseDesign. By way of increasing shaping accuracy and efficiency, the IDS (Inverse DistanceSquare) adaptive direct slicing algorithm for Additive Manufacturing is presented. For thefirst place, a new idea about direct slicing of dimensional point cloud data is raised. After that,the IDS adaptive direct slicing algorithm is proposed and slicing accuracy of this algorithm ishigher. Additionally, in curve contour reconstruction of the vertical projection-constructingplane,The Extended Approximation extrapolated models based on point clouds are set up.Finally, the angle error method and bow height error method are made use of to achievehomogenisation and refinement of curve reconstruction and profile data points. Then higherprecision and efficiency of this algorithm are tested and verified by practical fabricatingexamples.更多还原