应用回声状态网络的EGR阀电路在线诊断

为了实现废气再循环(EGR)阀电路控制性能能够满足车载诊断系统(OBD)的排放要求,应用主元分析(PCA)和回声状态网络(ESN)的融合理论,提出了柴油机EGR阀控制电路故障在线诊断策略.利用PSpice软件对EGR阀电路故障仿真的采样值作为PCA输入值,电路各元器件故障代码作为ESN输出值,进行了柴油机EGR阀电路故障的在线训练与诊断.基于PCA-ESN融合诊断策略,进行了EGR阀电路故障在线诊断试验.结果表明:故障诊断的正确率为94.3％;误判率为0.58％;拒绝率为0.15％.该诊断策略能够快速实现故障诊断及定位,确保了柴油机EGR阀在各种工况下快速、准确和可靠开启.     

汽油电控发动机EGR阀漏气故障诊断与排除

通过分析EGR阀漏气故障案例的诊断排除过程,说明了EGR阀故障诊断与排除的基本方法与程序。根据发动机EGR控制系统的类型、作用、工作原理及EGR阀结构和工作过程,以五菱B12发动机为例,论述了EGR阀漏气对发动机的影响及其故障特征,阐述了EGR阀漏气故障分析与诊断方法,提出了EGR阀漏气的故障排除方法。     

内燃机电子控制中基于Motohawk EGR阀控制模型设计

分析EGR阀电控系统的控制策略,利用motohawk搭建了发动机转速传感器模块、油门踏板位置传感器模块、节气门位置传感器模块、EGR阀位置传感器模块,并模拟水温传感器,根据不同工况下的EGR率要求处理上述传感器获得信号,借助查表法、经典PID控制算法,产生相应的PWM波驱动直流电机,带动EGR阀杆产生目标开度。     

4DB发动机EGR阀相关故障诊断分析

4DB发动机故障灯亮(EGR阀故障)有很多原因,通过对EGR阀故障诊断与分析,强调日常使用减少发动机内部积碳的产生以及定期保养清洗EGR阀与进气管的积碳的重要性,以保证发动机处于最佳的工作状态。     

带故障诊断的全隔离式电磁阀驱动电路设计

介绍一种带故障诊断的全隔离电磁阀驱动电路,电路在功率驱动、故障诊断、输出保护三方面都采用光电隔离方式,电流测量采用霍尔元件隔离方式;能够在线完成对MOS管及执行机构"短路"、"断路"的故障诊断,在系统发生故障时,切断电磁阀驱动电源,达到保护系统的目的。     

柴油机EGR阀位移传感器的设计与试验

为准确快速地检测EGR阀的开度,设计了EGR阀位移传感器的结构和信号处理电路,制定了结构和元器件参数的优化策略,并进行了参数最优匹配.根据国Ⅵ的OBD系统项目试验条款,对3款EGR阀位移传感器进行了自诊断、性能优化与排放测试等试验.结果表明:优化后的线性度误差、灵敏度误差和重复性误差分别0.32％、0.21％和0.56％,证实了制定的优化策略是切实可行的,表明了设计的EGR阀位移传感器适合柴油机在线实时检测要求,为柴油机满足OBD排放法规提供了保障.     

基于工程机械液压系统运行中的故障诊断技术研究

工程机械液压系统在实际运行中经常出现各种故障,快速诊断对于维护系统正常工作具有至关重要的作用。基于此,介绍工程机械液压系统的基本原理和结构,对液压系统常见的故障类型进行分类,包括液压泵漏油、阀门卡滞等,并分析不同故障诊断技术在工程机械液压系统中的应用。实践证明,通过了解液压系统结构和故障类型,选择合适的诊断方法进行故障诊断,并不断探索新的诊断技术,能够有效提高故障诊断的准确性,为工程机械液压系统维护保养提供良好的支持。     

基于神经网络的电动机逆变驱动系统故障诊断

针对电动机变频调速系统中逆变器开关元件故障类型多，传统故障诊断方法难以实现故障分离等情况，本文提出了一种基于神经网络的电动机变频调速系统故障诊断方法。通过对逆变器输出信号的谱分析可以获得对故障敏感的故障特征量，将这些故障特征量输入神经网络后，由网络输出层的结点输出可以判断故障类型，从而实现故障分离。研究结果表明，该方法可有效实现开关元件断路、短路故障，为进一步实现逆变器容错驱动奠定了理论基础。     

数控机床故障的诊断与维修实例

介绍了数控机床系统常见的故障及排除的方法和实例,具体包括数控机床的机械故障诊断和数控机床的电气故障诊断方法,并给出了维修实例。     

数控机床故障的诊断与维修实例

介绍了数控机床系统常见的故障及排除的方法和实例,具体包括数控机床的机械故障诊断和数控机床的电气故障诊断方法,并给出了维修实例.     

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.     

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.