基于航空发动机的总装脉动生产线技术

文中从航空发动机装配生产的自身特点入手,结合中国航空发动机发展的实际需求,设计了一种符合中国航空发动机装配特点的柔性化总装脉动生产线。通过对生产线柔性和效率的深度剖析与航空发动机装配工艺的实际调研,并根据脉动式生产线在航空发动机总装过程中的具体应用,提出了涵盖两大价值流、AGV(自动导引运输车)式发动机装配平台、贯穿整个生产流程的 AGV 中央控制系统和装配质量数据系统以及提高装配质量和效率的装配检测工具的装配理念,以此实现航空发动机脉动式装配以及装配数据的追溯与实时控制,高效精准地辅助航空发动机的总体装配。     

涡扇发动机装配脉动生产线分析

装配脉动生产线可有效缩短产品装配周期,大幅度提升生产管理及供应链管理水平,已成为国外大涵道比涡扇发动机装配的发展趋势。对比国内外发动机装配生产线现状,对国外发动机脉动装配生产线的应用情况及工作特点进行分析,指出国内建设涡扇发动机装配脉动生产线的注意要点,为今后研发先进航空发动机装配脉动生产线提供参考。     

汽车发动机装配线监控系统的设计与实现

该系统以OPC技术为基础,通过PC与PLC的通讯,实现了对发动机总装线各个工位加工状态的实时监控,显示现场电控设备出现的各种故障及报警,使整个装配线的状态可控,并对发动机装配过程中的数据进行采集,保存到SQL Server数据库中,为数据的后续SPC分析提供依据.设计了上传数据到服务器模块,处理了生产线上的突发事件对生产数据的影响,描述了系统和数据库的详细设计.运行结果表明该系统性能稳定,满足生产需要.     

混流装配线负荷平衡方法研究及应用

发动机混流装配生产线是对不同型号发动机顺序装配的流水线工艺程.为了提高装配质量和生产效率,充分利用资源,对发动机混流装配生产线规划设计的平衡问题和投产顺序问题进行了研究,建立了工作站内部和工作站之间负荷均衡以及最小化工作站闲置时间的数学模型,并通过实例验证了该方法有效地提高了整个装配线的生产效率.     

代理式装配线质量监控系统的智能决策

研究了质量监控系统中智能决策代理的结构、功能、控制策略及实现方法，并给出了部分实验结果。采用人工神经网络实现的决策Agent，通过对装配工艺参数的调整，能有效地控制发动机的重要性能指标，尤其对于装配过程中出现的产品质量问题，如泄漏不合格等，具有很好的预见性，对改进产品的装配质量能提出建设性意见。本文将智能Agent引入装配生产线质量监控系统，建立了基于多代理的装配生产线在线质量监控系统。该系统已在某汽车发动机装配车间得到应用。     

发动机装配过程中火花塞孔密封性测试失效问题分析和解决

针对发动机装配过程中出现的火花塞孔密封性失效问题,开展系统的根本原因分析,结合火花塞装配拧紧过程及失效发动机拧紧过程信息,确认了火花塞拧紧过程出现的垫片卡滞与火花塞孔密封性失效的因果关系。同时基于该根本原因分析结果和装配过程节拍需求,综合完成火花塞拧紧三阶段过程的拧紧参数优化,系统有效地预防了火花塞垫片卡滞情况的发生,解决了火花塞孔密封性失效的问题,在降低生产线返工成本的同时,提高了发动机装配一次性合格率。     

工业相机在发动机装配线的应用分析

在高度柔性的自动化生产线中,以工业相机为代表的工业相机凭借响应速度快和高可靠性的优势逐渐取代人工视觉,在工况监视、成品检验和质量控制等领域发挥着不可替代的作用。立足于汽车发动机装配制造系统,阐述工业相机系统的构成和原理,介绍现有生产线的工业相机应用状况,基于现有发动机装配生产线要求,前瞻工业相机的应用项目开发、拓展。     

基于价值流图分析的火箭氢氧发动机精益生产分析与改善

针对首都航天机械有限公司火箭氢氧发动机装配现场生产效率低、等待周期长、生产成本高等当前问题,提出了基于精益生产思想的氢氧发动机装配现场改善方法。结合现场原有的生产组织方式和装配工艺流程,绘制了改善前的价值流现状图,利用价值流图分析方法识别了装配过程中的各类浪费和瓶颈问题,结合航天生产特点提出了具体的改善措施,绘制了未来价值流图。通过优化装配工艺方法、平衡生产节拍、设备自动化、灵活配置人员等方式,实现了提高发动机装配效率、缩短装配周期的目的。应用5S管理与定置管理方法,实现了现场管理的科学化与规范化。通过精益生产方式的实施与应用,发动机装配效率、生产成本、现场作业环境、劳动强度得到明显改进,公司综合效益明显提升。     

基于数字化技术的航空发动机装配分析

通过对数字化装配技术的介绍,阐述了数字化装配的关键技术,解决了传统航空发动机装配精度受人为因素的诸多限制和装配质量无法保证的问题,优化了装配工艺方法、工装结构和生产线布局,实现了发动机装配的可行性、可达性,验证装配工艺设计的合理性,有效地提升了发动机的可靠性,是现代航空发动机制造技术的前沿研究方向,极大地提高了发动机制造水平。     

基于数字化技术的航空发动机装配分析

介绍数字化装配技术,着重论述了数字化装配的相关技术,为了解决航空发动机装配中的一系列问题,现在已有可行性较高的装配工艺方法、工装结构和生产线布局,保证了发动机装配的可行性,减小了出现相关漏洞的可能性,及时地检验装配工艺设计是否合理,优化航空发动机装配过程。     

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.     

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....     

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。     

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.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.