【作者】 庄梅玲；

【导师】 方建安；

【作者基本信息】 东华大学 ， 控制理论与控制工程， 2010， 博士

【摘要】 三维曲面展平技术是逆向工程技术的非常重要的一部分,通过对三维实物的测量研究及信息获取到二维图纸的制作,该技术为产品的快速研制开发以及快速原型化设计提供了一条捷径,被广泛的用于航空、机械、轻工、家电、汽车、玩具等领域。服装及人体曲面作为一种非常复杂的三维曲面,其曲面的研究及展平一直是三维服装CAD领域的难点,能通过智能化设计实现三维人体特别是服装曲面的自动展平,实现服装领域的自动智能打板,是很多学者研究的热点也是难点。目前对三维人体和服装曲面展平技术的研究,更多的从机械或者自动化角度进行,能够结合服装专业知识和人体特点的研究还是不多,展平后的曲面实用性比较差。同时对于人体和服装曲面的定义更多的是通过曲面拟合的形式实现,拟合度不高是主要的问题,或者对曲面进行简单的区域划分来进行定义,使服装曲面缺少一种精确的数学定义形式。本文针对三维服装曲面展平的研究状况,以标准女装人台模型为研究对象,提出基于形体特征点和特征线的三维数据测量方法,获取曲面数据,设计了基于特征点和线的曲面三角网格化方法。对网格化曲面上节点的离散高斯曲率的计算给出了计算公式,然后基于蚁群算法原理,提出了一种比较精确的定义复杂三维人体曲面的数学形式。基于胡克定律,提出了一种几何与物理结合的新型展平算法,提高了曲面展平后的实用性。最后结合服装打板和工艺归拔原理,针对不同的分割,设计了不同的物理修正算法,分别实现了展平,并对展平后的样板进行实物制作,对算法有效性进行评价和验证。论文的主要研究内容和创新点如下：1)基于形体特征的三维曲面数据获取技术的研究提出了基于形体特征的三维曲面数据获取方法,将决定服装样板造型的人体控制部位加入到服装曲面数据获取技术中。设计测量曲面上的关键点和关键线,对曲面上测量得到的节点进行三角网格化技术方面,提出了基于特征点和线进行有规律的三角网格化方法,得到了网格化的三维人台曲面以及各节点的拓扑信息。基于数据访问特点,提出了四维双向链表的数据存储方式。通过验证所设计的基于形体特征的数据获取方法及三角网格化技术对提高展平样板的实用性非常有效。2)基于离散高斯曲率的三维原型曲面的定义基于微分几何中的高斯曲率理论和Guass-Bonnet定理,设计了一种三角网格化模型,以线性表的形式将曲面上的节点表示为顶点集合和三角面片集合,给出了三角面片法向量的计算公式。基于模型,提出了一种离散化高斯曲率的计算方法,设计了算法对曲面上的节点计算离散化的高斯曲率。通过试验设计了一评判值,比较各节点高斯曲率的绝对值与评判值的大小,将节点定义成可展性节点和非可展性节点。3)衣身原型曲面的智能分割将蚁群优化算法应用到服装曲面的分割技术中,将衣身原型曲面的分割问题定义为过各节点寻找路径的旅行商问题(TSP),以区域节点所占各区域的平均百分比为评价目标确定是否终止搜索,建立了数学模型,设计了合适的信息素、更新概率和启发式信息等参数,并对算法的收敛性进行了分析了验证,实现了对曲面的分割。最后通过纸片实验,验证了算法的有效性。从而得到了衣身原型曲面上的两种区域分布：可展区域和非可展区域。4)非可展曲面的智能化展平算法的研究对非可展曲面,基于几何与物理相结合技术,提出了一种基于特征点和特征线的新型展平算法,算法首先沿形体上的特征点和特征线将曲面进行几何展平,然后基于胡克定律建立了一种新型能量评价模型,对几何展平结果进行物理修正。在能量释放问题上,考虑了与分割线位置分布的关系,提出了功能性分割线和非功能性分割线两种定义,并提出沿功能性分割线释放能量的展平算法,将本文算法与领域相关算法进行比较,得出本文算法既保证了曲面展平后的材料丝缕方向,又保证了能量积聚的最小化和样板形状的规则。5)基于省道转移原理和服装归拔技术的曲面展平算法的研究对各种分割线分布形式的衣身原型曲面,基于省道转移原理,提出将非功能分割线转变为功能性分割线的能量释放方法,设计辅助线进行分割线类型转变,在辅助线设计上提出了最短路径搜寻算法,与未进行分割线类型转变的展平结果进行对比,得出转变为功能性分割线的能量释放方法能有效减少能量积聚,提高样板的稳定性。对展平后样板的稳定性方面,提出基于材料归拔量的评价方法,建立了可归拔变形量的评价模型,选择可归拔变形量最小的材料进行样板变形量的评价,得出所展平的二维样板变形量都是处于可控范围的,然后提出将可展曲面部分和非可展曲面部分沿分界线进行拼接得到最终生产样板的方法,并输出样板,采用样布进行了制作试验,验证了算法的有效性。更多还原

【Abstract】 The technology for surface flattening is the important part of the converse projects. It is such work that the 2-D drawing is made through measuring the 3-D object. The technology has made the new products be researched, produced and becoming prototype more rapidly and expediently. It is widely used many fields such as aviation, mechanism, light industry, domestic wiring, car and toy design. The body and garment surface as the very complex 3-D surface are more difficult to be studied in the field of 3-D garment CAD. To flatten such surface by intelligent algorithm and realize the automatic intelligent pattern making are the studying hotspot and nodus for many academician.Now in the researching for 3-D surface flattening, the research for rigid surface as mechanism and aviation appliance is much, and they are also flattened intelligently. The study for body and garment surface is done from the angle of mechanism and automatics. The research is less that combined with the clothing specialty acknowledge and body feature. That leads to the bad practicability for flattened surface. The minimum of area changing fore-and-after the surface being flattened and the speed are paid more attention to. At the same time more research for body surface is to define the surface by the method of surface imitation. The imitation degree is not high is the exited problem. Another problem is some research only have the simple area dividing for the surface and a kind of accurate definition form for the body surface is not formed.According to the present researching condition, the article takes standard female model as studying object and a kind of new 3-D measurement and surface gridding method is brought forward which based on body feature points and lines. To calculate the discrete gauss curvature of the nodes on the surface the formula is given. Then basing on ant colony algorithm a more accurate mathematics definition forms for complex 3-D body surface is put forward. A new surface flattening algorithm is designed which combined with geometry and physics and based on Hook Law. Finally combining with clothing pattern-making and technical shrink and stretch principles, all kinds of surface with different dividing lines are flattened by designing physical amending algorithm. Using the flattened pattern to cut fabrics and sewing them into body surface, which is used to evaluate and test the efficiency of the algorithm. The major researching content and innovation are as following:1) The researching of data acquirement techniques for 3-D surface on body features.A kind of new 3-D surface data acquirement methods is put forward which based on body features. Some key points and lines that play the major role on the body are used to the data acquirement techniques of garment surface. The points and lines are designed and selected. These are also used to the surface gridding techniques. In order to triangulate the measured nodes the method based on surface featured points and lines is lodged and used. The gridding surface of body and the topology information of each node are got. Basing on the data visiting features, the 4-D bidirectional link list is designed as data memory mode. All those are verified to be very effective for the improvement of flattened pattern.2) The definition for 3-D body surface on discrete gauss curvature.A kind of new triangled model is set based on the Gauss Curvature theory from differential geometry and Guass-Bonnet theorem. Express the nodes as vertex and triangle muster by linear list. The calculation formula is given for normal vector of triangles. According to the model the algorithm is designed to calculate the discrete gauss curvature for each node. A evaluating value is set by test. All nodes are classified into two types as developed ones and undeveloped ones by comparing absolute value of gauss curvature for each node with the evaluating value.3) The research of intelligent partition technique for body surface.Apply the ant-colony optimization algorithm to surface partition. The partition for surface is defined as TSP that the optimizing path is found passing through nodes. Take average percentage of nodes as evaluating target function to determine whether the searching will end. A mathematics model is set. Such parameters as pheromones, updating probability and heuristic information are set by test according to actual problem. The astringency of algorithm is also analyzed and proved. The surface is divided into developed area and undeveloped one. The partition line is found also. Finally some papers are placed onto the body to verify the algorithm efficiency.4) The research of intelligent flattening algorithm for undeveloped surface. The new flattened algorithm for undeveloped surface is put forward. The algorithm is based on feature points and lines. It also combines geometric with physics. The algorithm firstly flattens the surface along feature points and lines according to geometric principles. Then a kind of new energy evaluating model is set up based on Hook Law. Using the model the geometric flattened result is amended. It is a kind of physical method. In order to deal with the problem of energy release during surface flattening, the position of dividing lines is analyzed and such two kinds of definition as functional partition lines and nonfunctional partition lines are brought forward. The flattening algorithm that releases the energy along functional partition lines is designed. By comparing the algorithm of this article with the correlative ones it can be got that the algorithm of this article not only make sure that the material’s basic longitude and latitude but also make sure that the minimum accumulated energy and regular pattern shape.5) The researching of surface flattening algorithm basing on dart transfer principles and clothing shrunk and stretched by ironing.For the body surface with all kinds of partition lines, different energy release algorithm is designed basing on dart transfer principles. In the algorithm the nonfunctional partition lines are transferred into functional partition lines. In order to realize those transferences the assistant lines are designed. The shortest path searching algorithm is put forward for the designing of assistant lines. The flattened result with partition lines type transferring is compared with that without partition lines type transferring. Such conclusion can be drawn that the new algorithm can effectively reduce energy accumulation and improve the pattern stability. In order to improve flattened pattern stability, an evaluating model for valuating material’s shrink and stretch deformable capacity is set up. Such fabrics with minimum shrink and stretch deformable capacity is selected to evaluate flattened pattern deformable capacity. By comparing such conclusion can be got that the flattened pattern deformable capacity in this article is within the scope of permission. Then the fabrics are sewn into surface to test the efficiency of algorithm. The result showed that the new algorithm in this article is good for the improvement the practicality of flattened pattern and also with good stability.更多还原