计及漂移瓶颈的时变物料配送路径优化

针对不确定作业车间环境下物料配送路径优化问题,采用能反映制造单元相对生产负荷及其变化趋势的瓶颈指数和瓶颈漂移指数表征实时变化的制造单元物料配送优先级,对路径选择过程中违反此优先级的行为设置惩罚成本,提出以最小化包括车辆运输成本和违反优先级的惩罚成本在内的总配送成本为优化目标,建立了时变的物料配送路径优化模型。在此基础上,为保证运输车辆所载物料全额配送,避免非必要负载以及由此造成的非必要配送子路径,对配送路径优化模型进行改进,允许运输车辆非满载和物料拆分配送,以提高物料配送效率降低配送成本;并结合模型特点将贪婪策略融入遗传算法对优化模型求解。最后,通过某作业车间内物料配送实例验证了所提出的计及漂移瓶颈的改进时变物料配送路径优化方法在不确定作业环境中具有有效性和实用性。     

集成自动导引车路径规划的智能制造数字化车间设备布局优化方法

智能制造数字化车间具有自动导引车(AGV)、加工设备高度集成的特点。针对智能制造数字化车间布局和AGV路径规划分开优化,使得某区域的物料搬运过于集中,导致该区域AGV搬运工作量繁重,影响AGV路径规划的问题,建立了以物流运输量最小,物料搬运时长最短以及AGV数量最少为目标的智能制造数字化车间布局和AGV路径规划集成优化模型。提出一种改进的带精英策略的快速非支配排序遗传算法,采用系统化布置设计法来生成部分初始种群,增加初始种群分布,防止陷入局部最优;将不等长的双链染色体与疫苗接种策略引入非支配排序遗传算法,提高了算法的寻优速度和精度;最后求解得到一组Pareto解集,供决策者优中选优。通过实例验证了所提方法的有效性。     

仿真环境下的泊位指派与箱位分配协调优化

基于企业车间配送作业效率问题,对车间位置布局分配进行研究,提出了在仿真环境下基于遗传算法的自动导引车(Automated Guided Vehicle, AGV)泊位指派与物料箱箱位分配协调优化模型。首先,通过分析物料运输作业过程中AGV泊位指派与物料箱箱位分配对配送作业效率的影响,建立以AGV行驶路径最短、物料箱的数量最少,以及单位班次生产线总产量最大为优化目标的数学模型;其次,基于Plant Simulation仿真平台搭建生产线仿真模型,结合遗传算法对车间位置分配策略进行优化调整,得到AGV泊位与物料箱箱位分配的最优方案;最后,以某制造企业的备料中心为研究对象,通过实例验证了仿真环境下基于遗传算法的AGV泊位指派与物料箱箱位分配协调优化的有效性。为提高备料中心配送作业效率提供了可参考的模型和算法,对提高备料中心作业经济效益具有积极的作用。     

设备鲁棒性布局与物料搬运系统协同优化方法

针对现有车间设备鲁棒性布局忽略物料搬运系统设计从而导致最终布局方案偏离全局最优解的问题,提出了一种设备鲁棒性布局及物料搬运系统协同优化方法。通过分析不同生产阶段设备间物流量及物流关系的变化,生成初始鲁棒性布局方案,并对每一种布局方案建立物流路径概率矩阵并进行路径规划。以物料搬运设备效率为约束,选择相应的物料搬运设备。以物料搬运成本及布局面积费用最低为优化目标,建立设备鲁棒性布局及物料搬运系统协同优化模型,采用遗传算法进行求解,得到更贴近实际生产的车间布局规划方案。通过实例验证了模型和算法的有效性。     

基于改进遗传算法的物料配送多目标优化模型研究

为解决装配车间物料配送过程中路径以及作业者数量不易确定的问题,以配送总时间和作业者数量为目标,同时考虑作业者的作业效率以及物料车的装载率,提出一种装配车间物料配送多目标优化模型,并采用改进遗传算法对模型进行求解。为解决多目标优化遗传算法求解过程中收敛速度慢且存在大量非可行解的问题,在算法设计过程中,将作业者配送路径和任务分配顺序进行实值分段编码,并在算法的交叉和变异中增加非可行解检验过程。以叉车装配为例,验证了物料配送优化模型的有效性。     

船舶曲面分段建造作业调度数字化仿真与优化

针对船舶曲面分段建造难度大、效率低的问题,对曲面分段车间建造作业调度过程进行仿真与优化研究。首先,提出基于虚拟流水线的分段建造车间作业调度模式;其次,基于数字化工厂策略实现其作业调度过程的仿真;以最大完工时间最小化为目标,提出基于遗传算法的作业调度过程优化;最后,以实际生产计划为对象进行了实例验证。结果表明:基于虚拟流水线的作业调度模式和基于数字化工厂策略的仿真优化,有效缩短了曲面分段建造周期,为提升船舶建造效率和水平提供了支撑。     

多品种混合装配车间配料区物料摆放布局优化

为了解决混合装配车间配料区的多品种物料摆放问题,提出了工人平均取料路径的概念,并以工人平均取料路径最短为目标,以配料区货架布局、货架容量等为约束条件,建立了以物料摆放位置为决策变量的数学模型。运用了改进的蚁群算法,该算法只允许至今最优解为蚁群搜索释放信息素。同时为了降低解的维度,采用二次解码方法对该问题进行求解。优化结果给出了不同货架物料摆放的布局。改进的蚁群算法具有比一般蚁群算法结果更优的特点。最后以某空调装配车间的配料区为实例,验证了该方法的有效性和可行性。     

复杂形状船舶分段建造空间调度优化算法

为了提高船舶分段建造场地装焊工场的利用率,提出复杂形状船舶分段的分层嵌套空间调度算法,算法将分段空间调度分为调度序列优化和布局寻优两个过程。针对不同的复杂形状分段提出一种通用的分段布局位置干涉检测方法,在此基础上采用栅格遍历与位置筛选的方法求解分段在装焊工场中的布局优化位置;分段调度序列采用基于优先级和遗传算法的混合排序优化方法,序列优化过程中调用分段布局寻优方法。计算结果表明,该算法可明显提高装焊工场的利用率,是解决分段空间调度的一种有效方法。     

基于实时碰撞检测的船舶曲面分段人机交互场地布局技术

针对船舶曲面分段的建造具有外形复杂、固定工位、混合场地的生产特点,为满足曲面分段建造规划对空间布局的精细化、可视化、高效化控制需求,提出了基于实时碰撞检测的曲面分段人机交互式场地布局技术。以曲面分段空间布局参数化注入建模为基础,研究了面向动态过程的曲面分段实时碰撞检测算法,实现了人机交互的可视化场地布局,解决了调整位姿、更换场地、更换时间的时空冲突问题;建立了具有结构化、可控化场地布局能力的技术机制。结合实际的工程实例运行分析,验证了技术的合理性与有效性。     

基于蚁群算法的减速箱装配件运输路径优化

针对某汽车减速箱装配厂零部件运输成本高、路径长的问题,运用蚁群算法对零部件运输路径进行优化。以运输长度为目标函数,划定坐标系,明确各零部件分厂所在坐标,并引入一种蚁群算法对路径进行优化。Matlab仿真结果表明,算法优化后运输长度较原先减少10.88%。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.