复合式汽车变速器最佳经济性速比优化算法研究

复合式汽车变速器,由金属带式无级变速器(continuously variable transmission,CVT)和有级变速传动装置组成,可根据汽车工况的需要分别实现无级变速传动和有级变速传动。综合考虑了发动机效率和CVT效率对汽车油耗的影响,提出了一种复合式汽车变速器最佳经济性速比优化方法。首先建立了动力传动系统的数值模型,为系统优化匹配和仿真分析奠定了基础。其次,建立了CVT最佳经济性速比匹配优化目标函数模型。基于simulation X软件,建立了装有复合式变速器的汽车仿真模型,对CVT的最佳经济性速比进行了优化,并对比分析了速比优化前后汽车的动力性和燃油经济性,证明了本文算法的有效性和实用性。     

车用摆销链式CVT速比控制参数优化策略研究

速比控制是变速器控制领域的关键技术之一。通过分析摆销链式CVT的结构及工作原理,采用模糊PID控制方法对汽车行驶循环工况进行仿真;搭建CVT传动系统数学模型和速比模糊控制器子模型,基于Simulink/Cruise联合仿真软件平台对模糊控制进行仿真研究;最后,引入遗传算法对速比控制器控制规则进行参数优化,分别对汽车起步工况和循环工况速比跟踪控制策略进行验证。结果表明,基于遗传算法的速比模糊控制对目标速比的跟随效果及误差变化均优于传统的模糊PID控制方法,可满足摆销链式CVT速比控制的要求。     

液力变矩器-机械无级变速器自动变速汽车综合控制策略研究

针对采用液力变矩器作为汽车起步和低速行驶时的调速装置,金属带无级变速传动为高速行驶时调速装置的双状态无级自动变速汽车,在液力变矩器台架试验的基础上,建立了双状态无级自动变速汽车的动力学仿真模型和金属带无级变速传动系统的综合控制策略,分析了分段加速行驶过程中,汽车液力变矩器和金属带无级变速器速比的变化规律,为开发设计双状态无级自动变速汽车提供理论依据。     

回流式无级自动变速传动系统设计方法研究

提出了新型回流式无级自动变速传动系统的设计方法。该设计方法以传动系统效率和速比变化范围为设计指标，确保汽车在各种行驶工况下传动系统效率在80％以上，在不同节气门开度下发动机稳态工作点均能位于最佳燃油经济线上。以长安羚羊SC7101轿车为例，完成了回流式无级自动变速传动系统关键参数的设计，为新型无级自动变速传动系统的研制开发奠定基础。     

基于发动机转速调节特性CVT速比模糊控制仿真研究

针对发动机的负荷特性和转速调节特性,建立了发动机的稳态转矩模型并确定了发动机的最佳动力性和经济性曲线,然后使用经济性加权系数法计算得出发动机的目标转速。将动力传动系统简化成双旋转质量模型,通过整车的数学模型利用Simulink建立物理模型,提出基于发动机转速调节特性的速比模糊控制方法,并分别对起步工况、制动工况和循环工况进行仿真。仿真结果显示:可以实现实际速比对目标速比很好的跟随效果,说明基于发动机转速调节特性的速比模糊控制方法能够很好的应用于速比控制。     

基于模糊免疫PID的CVT速比控制研究

针对装备金属带式无级变速器的某款车型,确定了发动机的目标转速调节特性曲线和无级变速器的目标速比,建立了CVT液压控制执行机构的数学模型。考虑到CVT速比控制的时变非线性和时滞耦合性的特点,借鉴生物免疫系统中的免疫反馈原理,结合模糊控制和PID控制各自的优点,设计了模糊免疫PID速比控制器,并在Simulink环境下对CVT整车模型起步、急加速和上坡工况进行了仿真分析。结果表明,模糊免疫PID速比控制能够很好地跟踪目标速比,具有良好的动态响应性能和较高的稳态控制精度。     

基于传动集成控制的锥环无级变速方法的研究

本文研究了一种新型汽车无级变速机构,其由两个圆锥体和一个金属锥环组成,锥环式无级变速器利用锥环本身的机械特性,实现变速器速比的转换。在Matlab/Simulink环境下建立了整车动力传动系一体化控制仿真模型,根据PID控制器的控制原理及特点对传统的PID控制器进行了改进,并对几种典型行驶工况进行了仿真分析,仿真结果表明,设计的调速控制策略能适应车辆各种行驶工况的要求,实际速比能很好地跟随目标速比。     

考虑CVT效率的无级变速车辆最佳经济性控制

传统的无级变速传动系统最佳经济性控制策略只考虑使发动机工作在其效率最高的工作点,并没有考虑无级变速器(Continuously variable transmission,CVT)效率对系统燃油消耗量的影响,而实际上无级变速器效率随其工况的变化在70%到95%之间变化,对系统燃油消耗量的影响是不可忽略的。在分析系统燃油消耗量与发动机效率和无级变速器效率之间关系的基础上,提出综合考虑发动机与无级变速器效率的最佳经济性控制策略,设计算法,以系统效率最高为优化目标,对各需求功率和车速下下发动机与无级变速器联合高效工作的目标转速和转矩进行计算。建立系统仿真模型,对优化前后的控制规律进行仿真对比分析,并在定车速工况下对优化前后的控制规律进行了对比试验。仿真及试验结果表明,综合考虑发动机与无级变速器效率的最佳经济性控制可以实现节油2%左右。     

基于模糊PID控制的CVT速比仿真研究

针对装备金属带式无级变速器的某款具体车型,建立了其发动机的转矩模型和油耗模型,基于此得出了目标转速调节特性曲线.之后,确定了无级变速传动的目标速比,并按照质量集中法简化了传动系统的模型.结合模糊PID的控制原理,提出了以CVT速比变化率为控制对象的模糊PID控制算法.在SIMULINK平台下对包含该控制算法的CVT整车...     

机电式CVT混合动力系统工况过渡控制

针对搭载机电式无级自动变速(Electric-mechanic continuously variable transmission,EMCVT)混合动力传动系统结构,采用枚举法分析了系统工作模式,将系统模式切换过渡工况归纳为发动机介入传动系统和退出传动系统两种情况。分别制定了两种情况下的控制逻辑和各阶段的控制目标,提出了发动机、电机、EMCVT和离合器综合协调控制的过渡工况控制策略。根据系统结构,建立了各关键部件的动力学模型,在MATLAB/SIMULINK仿真平台上,搭建了系统过渡工况控制仿真模型,分别针对发动机介入传动系统和退出传动系统两种情况进行了仿真。仿真结果表明,采用所提出的控制策略能大大降低系统冲击,提高模式切换品质,为机电控制CVT的应用提供理论参考。     

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.