混合动力挖掘机动力系统方案设计与仿真研究

基于公理设计(axiomatic design,AD)与发明问题解决原理(theory of inventive problem solving,TRIZ)的集成模型进行混合动力挖掘机动力系统方案设计,优选以超级电容和ISG(integrated starter generator)电机组成辅助动力源的并联混合动力系统方案.提出了发动机双模式转矩均衡控制策略,实现发动机工作点的自适应调节.混合动力挖掘机系统的SIMULINK建模仿真结果表明,方案及控制策略具有显著的节能效果.     

基于AMEsim的混合动力液压挖掘机系统建模及控制策略研究

为了能够从理论上对混合动力液压挖掘机进行研究,并找出有利于系统节能和降低排放的有效途径,以某20t液压挖掘机为原型,分析其动力系统各元件特性,并利用AMEsim软件建立并联式混合动力挖掘机系统的整机仿真模型.通过试验采集挖掘机在典型工况下的功率谱.根据挖掘机的工况特点,提出一种基于工况预测的准定工作点控制策略,并应用于仿真模型.仿真结果表明,所提出的控制策略能有效地减小超级电容电荷状态(SOC)波动,稳定发动机工作点,提高燃油经济性.     

一种液压挖掘机并联式混合动力系统结构及控制策略

为了能够从理论上对混合动力液压挖掘机进行研究,并从中找出有利于系统节能和降低排放的有效途径,以山河智能SWE230液压挖掘机为原型,分析其动力系统各元件特性,并利用AMEsim软件建立并联式混合动力挖掘机系统的整机仿真模型.通过试验采集挖掘机在典型工况下的功率谱.根据挖掘机的工况特点,提出1种基于工况预测的准定工作点控制策略,并应用于仿真模型.仿真结果表明,所提出的控制策略能有效减小超级电容荷状态(SOC)波动,稳定发动机工作点,提高燃油经济性.     

基于超级电容的并联式混合动力车转矩控制

针对并联式混合动力车动力系统中发动机和电驱动系统之间存在的能量分配和转矩协调问题,以发动机高效率工作为目的,建立了混合动力车前向式动力系统模型,以发动机稳态特性图和超级电容的SOC值为主要依据,设计了发动机和电动机间的转矩分配控制策略,仿真结果表明所建立的系统模型和协调转矩控制策略能够实时动态的控制发动机和电机的转矩分配,可有效的控制混合动力系统在高效区工作,既满足了系统对动力性的需求,又优化提高燃油经济性.     

轻度混合动力汽车动力性能仿真及动力系统参数匹配研究

介绍了采用起动机/发电机/电动机一体化技术的ISG(Integrated starter/generator)型混合动力汽车动力传动系统结构及控制策略,建立了装备双模式无级变速传动系统的ISG型混合动力汽车起步加速过程的动力学模型,并进行了计算机仿真。提出了轻度混合动力汽车动力系统的匹配设计方法,分析了电动机峰值功率、启动转矩和发动机启动转速对整车动力性能和传动系统转矩响应的影响,为轻度混合动力汽车总体设计提供了理论依据。     

并联式混合动力汽车转矩实时分配控制策略研究

为提高并联式混合动力汽车的整体效率,确保发动机工作在高效区的同时,动力电池不会因过度放电对使用寿命造成损害,对并联式混合动力汽车转矩实时分配控制策略展开研究。以全球轻型车测试规程(WLTP)为循环工况,采用马尔科夫链模型预测车辆在未来时域内的需求转矩,以未来时域内电机目标转矩占总需求转矩的百分比和电池SOC值作为输入,以转矩分配因子作为输出,建立模糊控制器,利用自适应模拟退火算法对模糊控制器的输出值进行离线优化,通过动态调节优化后的转矩分配因子实现需求转矩的合理分配,确保电池SOC值波动在设定的上下限内。在MATLAB和Cruise仿真平台中,对本文提出的控制策略进行联合仿真,并与逻辑门限值控制策略进行对比分析,结果表明:相比于逻辑门限值控制策略,转矩实时分配控制策略不仅保证发动机在高效区工作,而且电池SOC值的波动范围也保持在与初始值上下的3%以内,有效的改善了动力电池的使用寿命。     

混合动力液压挖掘机动力控制策略的研究

设计了一套液压挖掘机的节能液压系统,并且提出了具有超级电容混合动力液压挖掘机的全新结构和动力控制策略。通过计算机仿真,得出了对22吨并联式混合动力液压挖掘机的最优配置。     

纯电动汽车加速过程转矩优化策略

为了提升纯电动汽车在加速过程中的动力性能,解决纯电动汽车在起步和急加速过程中可能存在的电机输出转矩不足而不能满足驾驶员加速意图的问题,提出了一种基于模糊控制的转矩控制策略。首先通过电机转速和加速踏板开度确定纯电动汽车的基准转矩,然后根据纯电动汽车在不同车速所需要的电机转矩不同,建立了以车速和车速偏差为输入变量,以补偿转矩为输出变量的模糊控制器。最终通过基准转矩值和转矩补偿值确定电机的输出转矩,将转矩命令发送给电机系统。仿真结果表明,该控制策略能够有效提高纯电动汽车在加速过程的动力性能。     

基于遗传-蚁群算法的PHEB模糊控制策略优化

以并联式混合动力客车（PHEB）为研究对象,设计了以整车需求转矩与发动机最佳转矩之差以及超级电容荷电状态为输入,以发动机转矩为输出的模糊控制器,并应用遗传-蚁群算法对其进行隶属度函数和控制规则优化。基于MATLAB/Advisor建立了PHEB模糊控制策略模型和整车模型,并对优化前后的实例PHEB性能进行了仿真分析。研...     

基于典型作业工况的串联式电传动推土机功率跟随控制策略

为提高串联式混合动力推土机的燃油经济性,研究动力传动系统的能量分配策略。分析发动机和发电机的动态工作特性,通过台架试验建立发动机的动力输出特性模型、油耗特性模型和发电机的效率特性模型;通过超级电容的电阻串并联模型结构分析,建立超级电容的动态工作模型,设定荷电状态的安全工作范围。基于台架试验及模型获得的发动机最佳燃油消耗曲线,提出一种最佳燃油消耗曲线的功率跟随控制策略。研究推土机的典型作业工况,在典型作业工况下对提出的控制策略进行仿真,阐述超级电容的荷电状态及电压、电流的变化规律,并与传统机械传动结构的原型机在发动机工作转速、转矩、油耗和加速踏板位置变动等参数方面进行对比分析。结果表明,在推土机典型作业工况下,采用最佳燃油消耗曲线的功率跟随控制策略与原型机相比,节油率达13.1%。     

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.     

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....     

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.