动态规划在矩形毛坯单一排样中的应用

介绍矩形毛坯单一排样的概念和常用算法，其中的动态规划算法原理简单，容易实现，并根据其特点分析了动态规划算法在矩形毛坯单一排样中的应用。     

解决二维下料问题的最优两阶段排样方式

提出了一种用于生成矩形毛坯二维下料方案的同质块两阶段排样方式算法.下料方案中仅允许一种尺寸的毛坯出现在指定大小的矩形块即同质块中,从而简化了切割过程.该算法使用隐式枚举方法来考虑所有可能的同质块大小,从中选择最优同质块;结合线性规划确定最佳两阶段排样方式,以达到最佳效果.通过文献中的测题,将该算法与2种普通两阶段排样方式算法及普通T型排样方式算法进行比较,实验结果表明,该算法在计算时间和材料利用率两方面均有优势.     

解决二维下料问题的最优两阶段排样方式

提出了一种用于生成矩形毛坯二维下料方案的同质块两阶段排样方式算法.下料方案中仅允许一种尺寸的毛坯出现在指定大小的矩形块即同质块中,从而简化了切割过程.该算法使用隐式枚举方法来考虑所有可能的同质块大小,从中选择最优同质块;结合线性规划确定最佳两阶段排样方式,以达到最佳效果.通过文献中的测题,将该算法与2种普通两阶段排样方式算法及普通T型排样方式算法进行比较,实验结果表明,该算法在计算时间和材料利用率两方面均有优势.     

复合条带两段排样方式的生成算法

提出复合条带两段排样方式用以解决无约束二维剪切问题。这种排样方式首先将板材分成两个段,然后用若干条互相平行的水平或竖直剪切线将各段分别切成复合条带,最后将复合条带切成所需要的毛坯。采用确定型算法生成这种排样方式,求解背包模型分别生成毛坯在复合条带中的排样方式和复合条带在段中的排样方式,使用枚举算法确定最优两段组合,得到最终排样方式。采用文献中基准测题,将这种复合条带两段排样方式与文献中五种重要的排样方式进行比较。实验结果表明这种排样方式平均价值高于以上五种排样方式,且算法时间复杂度较低。     

有约束单一尺寸矩形毛坯下料问题的一种求解算法

讨论有约束单一尺寸矩形毛坯下料问题:切割库存板材满足一定数量的单一尺寸矩形毛坯的需求,优化目标是使所切割的板材总面积最小,该问题广泛的出现在制造业领域的板材切割下料环节。提出一种基于五块布局模式的优化下料算法。首先调用无约束五块布局算法生成整张板材上的毛坯排样方式,然后调用有约束五块布局算法生成部分板上的毛坯排样方式。使用算例对文中下料算法进行了测试,并与文献中下料算法进行了比较。实验结果表明,下料算法可以提高下料利用率,而且计算时间合理。     

冲裁件智能排样系统的研究

提出Hopfield人工神经网络与遗传算法相结合的算法,进行了智能排样系统的研究。该系统通过读入冲裁零件排样图形,自动计算出排样结果,并输出零件的优化排样图形。实例分析结果表明。该系统不但具有良好界面和人机交互功能,而且排样自动化程度高、提高了材料利用率。     

基于单毛坯条带的矩形件排样算法

提出一种基于单毛坯条带的矩形件排样算法,该算法采用三条剪切线将板材分成四个矩形区域,每个区域中包含一组方向和长度都相同的单毛坯条带。其中,用枚举的方法确定三条分割线的位置,用背包算法确定每个区域中条带的最优布局,使整张板材价值达到最大。将该算法与线形规划相结合形成基于单毛坯条带的矩形件排样方案生成算法,用于求解大规模矩形件排样问题。利用文献中报道的例题进行计算,实验结果表明该算法的计算时间满足实际应用的需要,并能在一定程度上提高材料利用率。     

改进的遗传算法在异形件优化排样中的应用

对于二维不规则图形零件在排样区域上的最优排列，也就是对二维不规则图形的计算机自动排样算法进行优化的问题。采用矩形包络算法、遗传算法和模拟退火算法相结合，寻找排样件在排样时的最优次序及各自的旋转角度。再用基于“最低水平线”策略的启发式排样算法实现二维不规则图形零件自动排样。从而得到满意的优化排样结果。     

计算机辅助设计冲裁工艺

介绍了冲裁工艺CAD系统、冲裁件图形交互输入过程、图形信息的输出、图形信息的提取、冲裁工艺性分析、毛坯排样及工艺方案的选择等。     

基于图形区域的同类零件自动优化排样算法实现

对于计算机的自动优化排样,提出了一种基于零件图形区域的动态定位算法,该算法用于某一类零件的单排或对头双排,既能排要效率,又能提高排样的自动化程度。     

Development of a Practical Blank Layout Optimisation System for Stamping Die Design

Blank layout is one of the most important processes in stamping die design. As the major cost in sheet metal stamping is the material cost, any efforts to minimise the scrap may result in substantial savings not only in strip material, but also in overall production. This paper is mainly targeted at establishing a practical blank layout optimisation system for stamp ing die by using AutoCAD’s ObjectARX toolkit. The basic principles of blank layout optimisation are first described, and then the general structure of the system is proposed. Not only a suitable algorithm for layout calculation, but also the manufacturing requirements and user operation are fully considered in this system. Finally, an algorithm for blank shape offsetting is proposed to solve the problem of self-intersection in offset curves, and the traditional ‘1-step tranzlation’ algorithm for the calculation of layout parameters is improved to eliminate the conflict between precision and efficiency in the layout optimisation.     

一种适于复杂零件排样的改进算法研究

在对排样问题进行了深入分析的基础上 ,对传统的平移算法进行了必要的改进 ,提出了一种新的优化算法并进行了验证。以该算法为核心的排样系统除可完成一般的卷料、条料、板料上的单排、双排和对头排外 ,还可求解嵌套排样问题 ,具有计算速度快、优化效果明显、优化结果可靠等优点     

设备布局离散优化问题的粒子群算法研究

设备布局设计是制造系统设计的重要组成部分，设备布局是否合理对整个制造系统的总体功效起着非常重要的影响。粒子群优化算法（PSO）是一种新的群智能优化算法，常用于求解连续空间极值问题，近来正逐渐进入组合优化领域。利用多雏实数编码及映射方法将连续PSO算法应用于求解设备环形布局问题，为此类离散优化问题的求解提供了一种新的思路。利用GA中的杂交策略扩展PSO算法，提高了PSO算法性能。通过实例计算和结果比较，说明了该算法能有效地求得设备环形布局问题的优化解，是一种行之有效地算法，有很好的实用价值。     

矩形件排样优化的背包算法

根据矩形件排样的实际下料工艺要求，将一个二维排样问题转化为一个一维下料问题，并构造了一个利用背包问题解法的矩形件排样的近似优化算法。     

APPLICATION OF INTEGER CODING ACCELERATING GENETIC ALGORITHM IN RECTANGULAR CUTTING STOCK PROBLEM

An improved genetic algorithm and its application to resolve cutting stock problem are presented. It is common to apply simple genetic algorithm (SGA) to cutting stock problem, but the huge amount of computing of SGA is a serious problem in practical application. Accelerating genetic algorithm (AGA) based on integer coding and AGA's detailed steps are developed to reduce the amount of computation, and a new kind of rectangular parts blank layout algorithm is designed for rectangular cutting stock problem. SGA is adopted to produce individuals within given evolution process, and the variation interval of these individuals is taken as initial domain of the next optimization process, thus shrinks searching range intensively and accelerates the evaluation process of SGA. To enhance the diversity of population and to avoid the algorithm stagnates at local optimization result, fixed number of individuals are produced randomly and replace the same number of parents in every evaluation process. According to the computational experiment, it is observed that this improved GA converges much sooner than SGA, and is able to get the balance of good result and high efficiency in the process of optimization for rectangular cutting stock problem.     

飞机钣金零件自动排料系统的设计与开发

基于最低水平线搜索排样算法,探讨了飞机钣金零件自动排料系统的设计与开发。与传统的依靠人工经验试凑排料相比,该系统可自动完成排料,同时可运用人工干预将小零件填满空白区域,从而获得了利用率较高的飞机钣金零件排料图,降低了生产成本,提高了零件的生产效率。     

飞机钣金零件自动排料系统的设计与开发

基于最低水平线搜索排样算法,探讨了飞机钣金零件自动排料系统的设计与开发。与传统的依靠人工经验试凑排料相比,该系统可自动完成排料,同时可运用人工干预将小零件填满空白区域,从而获得了利用率较高的飞机钣金零件排料图,降低了生产成本,提高了零件的生产效率。     

Research of knowledge-based system for stamping process planning

This paper gives a brief introduction to establishing a knowledge-based system for intelligent stamping process planning. Studies on the system’s framework, knowledge model and reasoning mode are introduced. Some key technologies such as the feasibility of the stamping process, an optimal algorithm for blank layout, intelligent strip layout and force calculation are researched. The efficiency of stamping process planning can be improved by the system.     

基于人机交互的遗传退火算法及其在履带起重机布局设计中的应用

针对履带起重机上车构件布局优化问题，给出一种基于人机交互的遗传退火算法。该算法在退火遗传算法的基础上引入“人机合作”思想，充分发挥人的主观能动性，改善了算法的性能。与传统算法相比，该算法收敛快、通用性好，适合求解复杂优化问题。利用本算法得出了符合工程要求的优化结果。     

Octree-to-BRep conversion for volumetric NC simulation

User-friendliness such as ease of creation and modification and system-friendliness such as space and time complexities, accuracy etc. are two important criteria for the selection of a solid representation scheme. No single solid representation scheme fully meets all the requirements of user-friendliness and system-friendliness. Hence, any practical CAD/CAM system maintains the geometry of the objects in more than one solid representation scheme simultaneously. Therefore, it is often required to convert one solid representation scheme to the other. The authors have developed a volumetric NC simulation system in which the instantaneous blank is represented as an octree as its space and time complexities are independent of the number of NC blocks. However, since octree does not lend itself readily for operations such as arbitrary transformations, rendered display etc., it is not directly usable for downstream applications such as animated display, verification and optimization. Boundary representation is suitable for these downstream applications. Therefore, it is required to convert octree of the instantaneous blank into BRep. An efficient algorithm for this conversion is presented in this paper. This algorithm essentially splits the octree into three quadtrees that store the geometry along the three principal directions. This algorithm is fast as it involves only tree-traversals.