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基于蚁群算法的零件多工艺路线决策方法研究 总被引:8,自引:0,他引:8
为满足企业对工艺规划的新需求,提出了采用蚁群算法进行多工艺路线决策的方法。在几何和技术需求以及可用加工资源的基础上,零件所有特征的各个加工阶段的工序节点构成了工艺求解空间,把加工工序安排的基本原理作为决策加工顺序的约束。采用蚁群算法对工艺求解空间中的所有工序节点在搜索规则的约束作用下进行遍历,最终寻找到能够完全满足工序节点搜索规则的优化工序序列。最后,用实例验证了该方法的可行性,证明该方法可以搜索出可行的工艺路线。 相似文献
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特征设计与工艺规划集成技术研究 总被引:1,自引:1,他引:0
针对CAD/CAPP数据与功能集成的需要,提出了基于特征设计与映射的特征工艺规划方案.通过调用特征库中标准的特征或用户定义特征(UDF)的实例完成零件模型设计.通过建立映射规则将设计特征模型重构为加工特征模型.通过建立工艺知识的决策规则与工艺知识库,将加工特征与加工方法、制造资源关联,实现基于特征的工序、工步的自动生成.特征工艺树通过与典型工艺模板的匹配构造工艺规划树,实现零件工艺路线的自动生成.通过人工交互编辑工序、工步及工艺路线、可输出完整的工艺文件. 相似文献
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基于特征的齿轮轴类零件工艺规程推理机制的研究 总被引:2,自引:0,他引:2
在基于特征的零件信息描述基础上,给出了适于齿轮轴类零件精度的特征描述方法。针对工艺过程中带有极大不确定因素的特点,将模糊推理与模糊知识相结合,通过模糊规则矩阵表达其工艺知识,通过模糊推理求得特征的最终加工工序以实现工艺过程的自动生成。 相似文献
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以回转类零件为对象,采用特征建模的方法构建了零件特征信息模型.以AutoCAD2004为平台,应用ActiveX技术和参数化技术,实现了轴类零件图形的参数化绘制.采用产生式规则对工艺知识进行归纳与表达,利用工艺知识特征建立了高效的推理机制,提出了工艺规程和工序的决策规则与算法,实现了回转类零件工艺决策的智能化. 相似文献
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在基于特征的零件信息描述基础上,给出了适于齿轮轴类零件精度的特征描述方法。针对工艺过程中带有极大不确定因素的特点,将模糊推理与模糊知识相结合通过模糊规则矩阵表达其工艺知识,通过模糊推理注得到征的最终加工工序以实现工艺过程的自动生成。 相似文献
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中国入世能否取得预期的效果,很大程度上取决于规则意识的强弱程度。本文提出入世必须树立较强的规则意识,且应循序渐进,即制定规则、学习规则、运用规则;并从企业和政府两个角度论述了如何树立规则意识,在WTO的规则框架内获取最大的收益。 相似文献
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A mixed dispatching rule approach in FMS scheduling 总被引:1,自引:0,他引:1
Nobuaki Ishii Joseph J. Talavage 《International Journal of Flexible Manufacturing Systems》1994,6(1):69-87
Short-term scheduling in flexible manufacturing systems (FMSs) is a difficult problem because of the complexities and dynamic behavior of FMSs. To solve this problem, a dispatching rule approach is widely used. In this approach, however, a single dispatching rule is usually assigned for all machines in a system during a given scheduling interval. In this paper, a mixed dispatching rule which can assign a different dispatching rule for each machine is proposed. A search algorithm which selects an appropriate mixed dispatching rule using predictions based on discrete event simulation is developed for this approach. The search algorithm for the mixed dispatching rule is described in detail. The effectiveness (in meeting performance criteria) of the mixed dispatching rule and the efficiency of the search algorithm relative to exhaustive search (complete enumeration) is demonstrated on an FMS model. The mixed dispatching rule approach performs up to 15.9% better than the conventional approach, and is 4% better on average. The statistical significance of the results is dicussed. 相似文献
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采用约束图 (无向图 )来表达几何系统的柔性约束关系模型 ,通过面向对象技术用类封装系统几何基元并通过无向图的扩展邻接多重表来构建该系统模型 ;对不同约束的具体处理方法可归纳并规范为处理规则 ,规则也采用规则图 (无向图 )的形式来表达 ,对于每一个规则 ,设一个标识。我们建立两种典型类型的规则图 ,对应于两种类型的规则图分别建立两个函数 ,在函数体中根据规则的标识将规则映射为方程(组 ) ,通过数值算法得到方程 (组 )的解 ;在约束模型推理求解过程中 ,根据人工智能技术中深度优先搜索算法并结合几何元素的自由度分析 ,搜索到可依次求解未知元素的约束子图 ,对于约束子图我们同样设一标识 ,约束子图和规则图通过标识相匹配 ,根据规则图的类型 ,调用对应于该类型规则的函数即可求解出约束子图中的未知元素 相似文献
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Rames C. Panda 《仪器科学与技术》2013,41(5):557-573
Abstract The control of various processes using a proportional-integral (PI) controller is investigated in this work. A new tuning rule based on the ultimate gain and phase margin specification is proposed. The tuning rule is given by analytical approximations. To obtain the tuning rule, a control signature is formulated using the ultimate properties of the system. The PI controller parameters are related with process model parameter to yield a model based tuning rule. Simulation examples are provided to demonstrate the performance and robustness of the present tuning rule. The new tuning rule requires a relatively small computational effort and is particularly useful for online applications. 相似文献
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提出规则蕴含的因果关系、充分性和必要性等不确定性规则的相关概念以及需要解决的规则不确定性问题,在此基础上介绍基于双参数的不确定性诊断规则的表示形式,进一步说明了规则条件参数计算方法和规则不确定参数的获取方法。与已有重要的不确定性知识的数值处理方法进行比较表明,该方法能够表示具有复杂不确定性加权关系的诊断规则,并且能够根据规则的约束条件通过数值计算获取规则的不确定性相关参数。实际应用结果表明,基于双参数的不确定性诊断规则表示方法是行之有效的。 相似文献
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Sandstone reservoir is one of the main types of oil and gas reservoirs in China. It has porous microstructure, which directly affects the transport properties of a sandstone. Hence, the study of porous microstructure is important to the exploration and exploitation of oil and gas. Three-dimensional microstructure of a sandstone can be reconstructed using the simulated annealing method based on statistical properties of its two-dimensional micrograph. The aim of reconstruction is to minimize the discrepancy between the statistical properties of the reconstructed microstructure and those of the two-dimensional image. To accelerate the rate of convergence, we proposed a different-phase neighbours (DPNs)-based pixel selection rule to replace the random pixel selection rule of the simulated annealing reconstruction. In this rule, pixels with the largest number of DPNs have the largest selection probability. The selection probabilities of other pixels are proportional to their DPNs. Microstructure reconstructed with the DPNs-based rule is compared with those with the random selection rule and two other biased pixel selection rules. The DPNs-based rule is the most effective in enhancing convergence. Permeability of the microstructure reconstructed with the DPNs-based rule is estimated by the Kozeny–Carman formula and is in good agreement with the one reconstructed with the random pixel selection rule. 相似文献
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针对协商过程的时态关联具有近似性的特点,提出了一种基于聚类的近似时态关联规则挖掘方法.该方法通过对特定关联模式的实例进行聚类,找到满足给定条件的时态关联规则,并给出规则中各属性取值以及关联间隔约束的有效范围.近似时态关联规则较一般的关联规则具有更强的灵活性和适应性,其对规则的描述更符合协商中的情况. 相似文献