共查询到19条相似文献,搜索用时 109 毫秒
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针对木工板手工排样效率低和材料利用率低问题,提出木工板“一刀切”排样优化算法.在剩余矩形填充算法中添加启发式分块原则,改进的剩余矩形填充算法满足“一刀切”工艺要求.采用遗传算法对矩形件进行排样优化,以提高木工板利用率,降低企业生产成本.为提高算法的优化精度,使用基于指数变换的非线性动态适应度函数,引入精英保护策略,应用部分填充交叉(partially matched crossover)算子.结合剩余矩形填充“一刀切”算法对遗传种群进行解码计算原料利用率,并作为适应度函数值,进行迭代搜索最优解.排样实例表明木工板“一刀切”排样优化算法能够很好地解决多品种大规模木工板排样问题. 相似文献
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矩形优化排样问题是一个在制造业领域生产实践中普遍遇到的问题,采用了一种改进的最低水平线搜索算法求解此类问题.首先分析了原始的最低水平线搜索算法在排样中存在的缺陷,并针对该缺陷为其设计了一个评价函数,排样时对所有未排零件进行评价,选择评价值最高的零件排入当前位置,从而克服了算法在搜索过程中的随机性,优化了算法的搜索方向.实验仿真的结果表明,提出的算法可以得到较好的排样效果,并且其解决问题的规模越大,优化性能越好,适合于求解大规模排样问题. 相似文献
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提出一种利用人工神经网络求解不规则件排样问题的混合优化方法.该方法首先把排样和制造工艺联系起来,将多边形各边向外扩充,为零件预留加工余量;然后采用自组织特征映射模型(SOM)和Hopfield人工神经网络相结合的方法,运用SOM神经网络对初始在板材内随机排布的不规则零件进行平移,逐步减小不规则零件之间的重叠面积,求得各零件的最优位置,再运用Hopfield神经网络对平移后的零件旋转,进行迭代运算,当能量函数达到稳定状态时,得到各排样零件的最优旋转角度组合,实现自动排样.算法可以解决不规则件和矩形件在规则板材以及不规则板材上的排样问题,实例证明了该算法的有效性和实用性. 相似文献
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对于"一刀切"矩形件优化排样问题,采用遗传算法与蚁群算法的混合算法进行研究.针对两种算法的传统混合策略和现有混合策略的不足,对两种算法的混合策略进行改进,并利用种群本身的染色体适值来判断种群进化是否停滞,确定了算法的最佳融合时机.对具体算例的分析验证表明,改进后的混合策略可有效减少算法的冗余迭代次数,提高搜索速度,是一种行之有效的排样算法. 相似文献
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针对理论上属于NPC问题的非规则件优化排样问题,论文提出一种基于小生境技术的自适应遗传模拟退火算法与基于内靠接临界多边形最低点的启发式布局算法相结合的方法。考虑到算法中交叉概率和变异概率的选择影响到算法收敛性,提出了自适应的交叉概率和变异概率,通过基于小生境技术的遗传模拟退火算法对非规则件排样的最优顺序和各自的旋转角度进行优化搜索。将非规则件定位在有缺陷原材料和非规则件多边形的内靠接临界多边形最低点以实现个体的解码,同时避开了原材料表面缺陷。排样实例表明,该优化排样算法行之有效,具有广泛的适应性。 相似文献
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基于现有的优化排样算法,模拟鸡蛋孵化过程,设计一种孵化算法来解决排样问题。算法是对实际生活中存在现象的抽象和改进。将寻找最优解整个过程划分为占位,孵化,挤兑,抢占,复活,五个阶段,探索状态下排布决策的适应性,从而得到排样件在排样时的最优次序和最大可容纳的样本数目。 相似文献
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目的针对产品设计中操作界面布局设计时存在的随意性、不确定性大等问题,使用多目标优化设计的方法,寻找界面元素的最优布置,以提升界面的使用舒适性和人机交互效率。方法在分析了工效学准则和界面布局美度评价准则的基础上,确立了层次性、相关性、简洁性和舒适性四个界面布局基本原则,并依据原则构建了界面元素布局多目标优化数学模型,在此模型的基础上采用改进的遗传算法,建立基于遗传算法的界面元素布局多目标优化方法。结果给出产品操作界面布局设计的基本原则,提出一种基于遗传算法的产品操作界面元素布局的多目标优化方法及流程。结论提出的布局原则和优化方法能较好地协助设计师获得满足设计需求的布局方案,实例结果表明了理论模型的合理性与遗传算法对于界面元素布局多目标优化问题求解的有效性。 相似文献
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In this paper a new graph-based evolutionary algorithm, gM-PAES, is proposed in order to solve the complex problem of truss layout multi-objective optimization. In this algorithm a graph-based genotype is employed as a modified version of Memetic Pareto Archive Evolution Strategy (M-PAES), a well-known hybrid multi-objective optimization algorithm, and consequently, new graph-based crossover and mutation operators perform as the solution generation tools in this algorithm. The genetic operators are designed in a way that helps the multi-objective optimizer to cover all parts of the true Pareto front in this specific problem. In the optimization process of the proposed algorithm, the local search part of gM-PAES is controlled adaptively in order to reduce the required computational effort and enhance its performance. In the last part of the paper, four numeric examples are presented to demonstrate the performance of the proposed algorithm. Results show that the proposed algorithm has great ability in producing a set of solutions which cover all parts of the true Pareto front. 相似文献
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Hybrid heuristic algorithms are proposed for the nesting of two-dimensional rectangular parts in multiple plates. The nesting algorithm of Babu and Babu is first modified and a new heuristic nesting algorithm, IBH, is proposed to utilize the material plate further. IBH is then combined in a meta-heuristic approach, simulated annealing. The proposed hybrid algorithms can then be extended to solve the nesting problem involving irregular parts by embedding irregular parts to rectangles. One problem arises in this 'irregular-to-rectangular' process, i.e. conversion of demands of the original irregular parts into demands of the embedding rectangles. A greedy heuristic rule is therefore presented to determine the number of embedding rectangles of different types to be used in order to maximize the utilization of the material plate given that the demand of each irregular part must be satisfied. Promising computational results are obtained and reported by running examples from the literature and data relevant to the footwear industry. 相似文献
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The optimal fixture layout is crucial to product quality assurance in the multi-station sheet metal assembly processes. Poor fixture layout may lead to product variation during the assembly processes. In this paper, a genetic algorithm (GA)-based optimisation approach has been presented for the robust fixture layout design in the multi-station assembly processes. The robust fixture layout is developed to minimise the sensitivity of product variation to fixture errors by selecting the appropriate coordinate locations of pins and slot orientations. In this paper, a modified state space model for variation propagation in the multi-station sheet metal assembly is developed for the first time, which is the mathematical foundation of optimal algorithm. An e-optimal is applied as the robust design criteria. Based on the state space model and design criteria, a genetic algorithm is used to find the optimal fixture layout design. The proposed method can greatly reduce the sensitivity level of product variation. A four-station assembly process of an inner-panel complete for a station wagon (estate car) is used to illustrate this method. 相似文献
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为避免单元系统布局和单元内设施布局分开孤立研究所导致的问题解空间损失,利用并行工程的思想对单元布局的两个环节集成考虑,对单元系统布局、单元内设施布置、设施摆放方向进行同时描述,并建立多目标集成优化模型。针对模型的复杂性,设计了改进粒子群算法,算法吸收了遗传算法中的交叉操作算子,具有跳出局部最优解的能力。最后通过求解单元设施布置实例,验证模型和算法的有效性。 相似文献
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A. S. Gogate 《国际生产研究杂志》2013,51(20):5607-5631
Significant savings in cost and time can be achieved in rapid prototyping (RP) by manufacturing multiple parts in a single setup to achieve efficient machine volume utilization. This paper reports the design and implementation of a system for the optimal layout planning of 3D parts for a RP process. A genetic algorithm (GA) based search strategy has been used to arrive at a good packing layout for a chosen set of parts and RP process. A two stage approach has been proposed to initially short-list acceptable orientations for each part followed by the search for a layout plan which optimizes in terms of final product quality and build time. The GA uses a hybrid objective function comprising of the weighted measures like part build height, staircase effect, volume and area-of-contact of support structures. In essence it captures the key metrics of efficiency and goodness of packing for RP. The final layout plan is produced in the form of a composite part CAD model which can be directly exported to a RP machine for manufacturing. Design methodology of the system has been presented with some representative case studies. 相似文献
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In this paper, we present an algorithm that solves a paper reel layout problem where the available space is divided into equal-size cells. The problem is to find a layout with the minimum transportation cost subject to adjacency and other constraints. A genetic algorithm is used in a two-stage iterative approach to solve the problem. Computational results seem to indicate the efficiency and effectiveness of the proposed solution method. 相似文献
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This paper deals with the problem of generating 2D cutting paths for a stock plate nested with a set of regular and/or irregular parts. The objective of the problem is to minimize the total non-productive traveling distance of a cutter starting from a known depot, then cutting all the given parts, and returning back to the depot. A cutting path consists of the depot and piercing points, each of which is to be specified for cutting a part. The cutting path optimization problem is shown to be formulated as a generalized version of the standard traveling salesman problem. To solve the problem, a two-step genetic algorithm combining global search for piercing point optimization and local search for part sequencing is proposed. Traditional genetic operators developed for continuous optimization problems are modified to effectively deal with the continuous nature of piercing-point positions. A series of computational results are provided to illustrate the validity of the proposed algorithm. 相似文献