共查询到20条相似文献,搜索用时 140 毫秒
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针对考虑关节弹性的冗余度机器人具有最小力矩的轨迹规划问题进行了研究,提出了可用于实时控制的规划算法,并给出了平面3R机器人的仿真实例。 相似文献
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为了提高复杂产品的装配效率,对遗传帝国竞争混合算法进行了研究与改进,给出了混合算法的融合策略,以解决虚拟装配中的装配序列规划问题。建立考虑装配序列可行性、装配序列稳定性、装配重定向性以及装配聚合性四个评价指标的适应度函数,以适应度函数值最低为目标利用混合算法进行迭代。以某乘用车后桥减速器为实例进行试验,验证了混合算法在求解装配序列规划问题的可行性,并同单一的遗传算法、帝国竞争算法及粒子群算法进行比较,验证了混合算法在求解装配序列规划问题上的优越性。 相似文献
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面向STEP-NC控制器的数控加工工艺规划模型 总被引:6,自引:0,他引:6
STEP-NC是欧美提出的一种用以取代ISO 6983的新数控接口标准(ISO 14649)。分析了STEP-NC数据模型及其对数控系统的影响,基于STEP-NC的基本思想将数控加工中的工艺规划划分为离线规划、在线规划和实时规划,重点研究了基于STEP-NC控制器的在线规划问题。为了避免过多地占用加工时间,提出了按工步级规划→特征级规划→零件级规划的在线规划模式,并据此分别给出了工步级铣削用量的优化模型、特征级工艺路线的筛选方法以及基于启发式算法的工步排序方法。 相似文献
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矩阵链乘积最优计算次序问题的算法,是一个经典的计算机算法设计问题。本文在分析最优解结构的基础上,基于动态规划算法,用Java语言给出解决该问题的一个通用的程序。全文分为四个部分,首先讨论了动态规划时间效率优化的可行性和必要性,接着给出了动态规划时间复杂度的决定因素,然后分别阐述了对各个决定因素的优化方法,最后总结全文。 相似文献
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基于时间约束网络的动态规划调度算法 总被引:5,自引:0,他引:5
为解决与时间有关的规划调度问题,提出了一种基于时间约束网络的动态算法。该算法与传统的计算最短路径方法不同,它只需计算受到新增约束影响的局部网络。同时,给出了算法的最坏时间复杂性,并进行了证明。最后,以Job—Shop调度系统为例进行了仿真验证,结果表明,该算法可快速地判断约束网络的一致性,并计算每个工序的最早可能开始时间。 相似文献
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基于Ray Casting的医学体数据场绘制算法 总被引:1,自引:1,他引:0
在医学体可视化中,Ray Casting算法由于具有高的计算需求、模糊的绘制质量和复杂的分类等缺陷,限制了该算法的进一步应用。为此,本文定义了一种多种因素相结合的光学属性赋值方法,该方法将物体距离视点的距离与物体距离光源的距离有效结合起来。在此基础上提出了一种高效精确的医学体绘制算法,该算法首先将医学体数据场进行分类,对于前景体素集采用LOD(Layer of Detail)技术进行重采样,进而将采样点用上述定义进行赋值;最后将背景体素采用基于空间跳跃的加速技术进行显示。实验结果表明对于512×512×482×2 Byte大小的体数据,在普通微机上能够达到2.5 fps的绘制速度;而且组织器官显示清晰,符合人的视觉特征。 相似文献
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Pei-Chann Chang Hui-Mei Wang 《The International Journal of Advanced Manufacturing Technology》2004,24(7-8):615-620
This paper studies the problem of scheduling semiconductor burn-in operations, where each job has non-identical lot sizes and an oven (a batch processing machine) that processes several jobs within its capacity limit simultaneously. We present some properties of the problem and an efficient heuristic algorithm. In a computational experiment, pairs of burning operations (,) were presented with the arrival time ri and processing time pi for different (,) pairs to examine the effect of arrival time and the processing time on minimising the total completion time. The result shows that a ratio of to greater than 1 was superior to other ratios, which can be a guide for schedule planners of burn-in operations. The heuristic obtains a satisfactory average performance rapidly. This revised version was published online in October 2004 with a correction to the issue number. 相似文献
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Deming Lei 《The International Journal of Advanced Manufacturing Technology》2011,55(9-12):1183-1192
The problem of scheduling stochastic job shop subject to breakdown is seldom considered. This paper proposes an efficient genetic algorithm (GA) for the problem with exponential processing time and non-resumable jobs. The objective is to minimize the stochastic makespan itself. In the proposed GA, a novel random key representation is suggested to represent the schedule of the problem and a discrete event-driven decoding method is applied to build the schedule and handle breakdown. Probability stochastic order and the addition operation of exponential random variables are also used to calculate the objective value. The proposed GA is applied to some test problems and compared with a simulated annealing and a particle swarm optimization. The computational results show the effectiveness of the GA and its promising advantage on stochastic scheduling. 相似文献
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Irina Ioachim François Soumis 《International Journal of Flexible Manufacturing Systems》1995,7(1):5-26
In this paper, we analyze the efficiency of a given robot movement schedule for the case of a flow shop robotic production cell withm different machines, one input conveyor, and one output conveyor. We begin with the case of one-robot cells and extend our results to multirobot cells. The paper studies the efficiency of a movement schedule for identical parts by defining a movement network associated with this schedule. This network models any cell layout and applies to multirobot cells. Using the movement network, we propose two cycle time evaluation methods, the first using linear programming and the second based on finding a longest path. The latter method generates a procedure to obtain an analytical formula for the cycle time. We extend the proposed methods to study the efficiency of a given input sequence (schedule) for different parts, that is, to determine the sequence processing time. The results obtained here allow us to quickly evaluate the efficiency of any given feasible movement schedule, for identical or different parts. 相似文献
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P. Udhayakumar S. Kumanan 《The International Journal of Advanced Manufacturing Technology》2012,61(5-8):621-635
Effective sequencing and scheduling of the material handling system (MHS) have an impact on the productivity of the flexible manufacturing system (FMS). The MHS cannot be neglected while scheduling the production tasks. It is necessary to take into account the interaction between machines and MHS. This paper highlights the importance of integration between production schedule and MHS schedule in FMS. The Giffler and Thompson algorithm with different priority dispatching rules is developed to minimize the makespan in the FMS production schedule. Its output is used for MHS scheduling where the distance traveled and the number of backtrackings of the automated-guided vehicles are minimized using an evolutionary algorithms such as an ant colony optimization algorithm and particle swarm optimization (PSO) algorithm. The proposed evolutionary algorithms are validated with benchmark problems. The results available for the existing algorithms are compared with results obtained by the proposed evolutionary algorithms. The analysis reveals that PSO algorithm provides better solution with reasonable computational time. 相似文献
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针对柔性作业车间调度和预防性维护的单目标集成优化问题,以最大完工时间为优化指标,建立了基于维修时间窗的集成优化模型,设计了混合“教与学”优化(HTLBO)算法求解该模型。提出一种“基于工序加工时间最短”的机器序列初始化策略,对部分初始种群进行初始优化,以提高部分初始解的质量,使得算法能够以较短的时间收敛。对文献中柔性作业车间调度的基准问题进行求解并比较其计算结果,初步证明该混合算法的可行性;针对集成维修时间窗的柔性作业车间调度优化模型,借鉴文献中的数据生成实例进行求解,并与其他算法进行比较,证明该混合算法的有效性。 相似文献
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基于遗传算法的支持向量机时间序列预测模型优化 总被引:14,自引:0,他引:14
建立在统计学习理论和结构风险最小原则上的支持向量机在理论上保证了模型的最大泛化能力,因此与建立在经验风险最小原则上的神经网络模型相比,理论上更为完善。本文运用支持向量机建立时间序列预测模型,研究影响模型预测精度的相关参数,在分析参数对时间序列预测精度的影响基础上,提出用遗传算法建立支持向量机预测模型的参数自适应优化算法。最后,用算例表明了本文算法的正确性和有效性。 相似文献
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需求提前期分布对供应链牛鞭效应的影响分析 总被引:3,自引:0,他引:3
汪传旭 《计算机集成制造系统》2007,13(5):995-1000,1007
为研究需求提前期在节点企业之间的不同分布对供应链牛鞭效应的影响,构建了基于时间序列自适应过滤预测和指数平滑预测方法所得出的多节点企业供应链条件下牛鞭效应的一般数学模型,并据此模型从理论和实证两方面进行了说明,所得结论为企业通过合理计划需求提前期和实现供应链网络重构来减小供应链牛鞭效应提供了参考. 相似文献