Fault diagnosis of AMT gear shifting process based on semi-quantitative SDG model

In order to diagnose gear shifting process in automated manual transmission（AMT）,a semi-quantitative signed directed graph（SDG）model is applied.Mathematical models are built by analysis of the power train dynamic and the gear shifting control process.The SDG model is built based on related priori knowledge.By calculating the fuzzy membership degree of each compatible passway and its possible fault source,we get the possibilities of failure for each possible fault source.We begin with the nodes with the maximum possibility of failure in order to find the failed part.The diagnosis example shows that it is feasible to use the semi-quantitative SDG model for fault diagnosis of the gear shifting process in AMT.

Investigation of the Effects of Profile Shift in Helical Gear Mechanisms with Analytical and Numerical Methods

In this paper, the effects of profile shift in cylindrical helical gear mechanisms have been investigated with numerical and analytical calculations. The mathematical model for computer simulation of gears has been designed and the numerical calculations have been carried out. Analytical calculations have been made with an excel program which was designed at different profile shift coefficients for a selected mechanism. Analytical calculations of the same mechanism have been verified by using ANSYS 14.5. The results of analytical and numerical solutions have been compared to profile shift coefficients.

Analysis on the gear-shifting schedule of hydraulic automatic transmission

With an advanced foreign hydraulic automatic transmission as the objective,an analytical method for the gear-shifting schedule is proposed.First the demanded maximum gradient of test is estimated.Then a test scheme and analytical procedure is formulated by initial test and hypothetical shift parameters.Finally through gear-shifting tests under different road conditions,load,accelerator pedal position limitation,throttle opening and output shaft speed are found to be the gear-shifting parameters.Under a common road condition,the gear-shifting schedule is a double-parameter schedule.Based on the driver＇s demands on braking and dynamic performance,different shift schedules are made under downhill,uphill and quick releasing acceleration pedal conditions.The operation criteria of down-shift schedule on abrupt grade are proposed.

Simulation of automobile fuel consumption and emissions for various driver's manual shifting habits

The effects of different habits of the drivers on gear shifting strategies for manual powertrain were investigated. For the realization of simulation, the shifting habits of the drivers were conducted in the Advisor software to investigate and compare the emission rates. Simulation was developed based on the optimal gear shifting strategy and criteria and was validated both in fuel economy and emissions by analyzing the results in the various driving cycle and driving styles. To explore an optimal gear shifting strategy with best fuel economy and lowest emission for a manual transmission, a strategy was designed with a highest possible gear criterion as long as the torque requirement can be satisfied. Based on two different criteria, namely the engine working conditions and the driver's intention, the governing parameters in decision making for gear shifting of manual transmission in conventional engine were discussed. It is also shown that the optimum gear shifting strategy is based on that both the engine state and the driver's intention eliminates unnecessary shiftings that are present when the intention is overlooked. The optimum shifting habit and the best driving cycle in terms of minimum emissions and fuel consumption were proposed.

Design and analysis of shift robot with passive joint

In order to improve the efficiency of gear shifter testing,a kind of shift robot with a special pas-sive joint is proposed to complete the human-like shifting operation automatically.The shift robot is mainly composed of two prismatic pairs,a cylindrical pair and a passive joint.The two prismatic pairs act as actuators of the mechanism to complete a part of the shifting operation,and then the shift lever can be pulled into the accurate gear position by the shift torque of the gear shifter.However,the shifting lever may skip the target gear position into the next gear position.In order to solve the gear-skip phenomenon,a limit block is applied to the passive joint.Then,the shifting processes are simulated through the dynamic model of the shift robot.The optimal position of the limit block is de-termined based on its dynamic characteristics.

Methods for the Gear-Position Decision in AMT

Aimed at defects of the gear position decision in an automatic mechanical transmission, a method of synthetic shift schedule of 5 speed gear position is presented, which is based on the fuzzy discernment of the driver intention and the road characteristics. A contrastive experimental analysis between the synthetic gear position decision method and the traditional gear position decision method is given by analyzing Santana 2000.

CNC FLEXIBLE GENERATING SPECIFIC GEAR TOOTH PROFILE BASED ON STANDARD INVOLUTE GEAR HOB

A new method named orthogonal two-way link-shift here has been proposed.Based on the method and a standard involute gear hob, a specific gear tooth profile (including anarbitrary gear tooth profile and a modified involute gear tooth profile) can be generated on aCNC(computer numerical control) bobbing machine. Computer simulation has been carried out, and theresults prove that the method is right and practicable. So, the fabrication costs can be greatlydecreased than before. The new method has momentous significance to realize gear's optimizedmodification under different work conditions.

Analysis of Gear Breakage and Countermeasures Based on Fault Tree

Gears are important parts of mechanical products and have been widely used in various industries.A spur gear was broken early in a transmission chain.This article starts with the breakage fault of the gear.The processes of fault analysis and improvement countermeasure were comprehensively sorted out based on fault tree,and the relevant influencing factors which affect the life of gears were examined one by one.Through detailed investigation,the abnormal high load on the gears was clarified.The gear design strength reserve did not meet the requirements for customer-specific operating conditions,and further improvements had been made.By optimizing the oil-filling characteristics and timing matching of the hydraulic system,the impact of shift shock was reduced,thereby reducing the load on the gears.At the same time,by increasing the pressure angle of the gear,the gear strength margin was increased from the design point of view.Through the fatigue test on the bench,the gears worked safely.After further verification of the actual vehicle test,the gears worked safely and normally,so the improvement measures were effective.This article provides a useful reference for trouble shooting processes and a problem solving method for similar faults through detailed analysis of factors affecting gear life.

激励频率对换挡行星传动系统非线性动力学影响分析

换挡机构是变速系统中最关键的部件之一,其性能直接影响传动系统的动力性和平稳性。建立了二级换挡行星传动系统动力学方程,研究了外界激励频率对传动系统复杂动力学特性的影响;通过分析分岔图、时域响应图、相图、庞加莱截面图以及频谱图变化规律,明晰了二级换挡行星传动系统混沌振动特性,获得了外界激励频率稳定振动区间;利用比例微分控制方法对传动系统混沌振动进行控制,将混沌振动调整为稳定的单周期振动。研究结果为提高换挡行星传动系统运转的稳定性奠定了基础。

Mesh stiffness evaluation of an internal spur gear pair with tooth profile shift

Tooth profile shift will change the thickness of gear teeth and a part of geometrical parameters of a gear pair, thus influencing its mesh stiffness and consequently the dynamic performances. In this paper, an analytical mesh stiffness calculation model for an internal gear pair in mesh considering the tooth profile shift is developed based on the potential energy principle. Geometrical representations of the tooth profile shift are firstly derived, and then fitted into the analytical tooth stiffness model of gears. This model could supply a convenient way for mesh stiffness calculation of profile shifted spur gears. Then, simulation studies are conducted based on the developed model to demonstrate the effects of tooth profile shift coefficient on the tooth compliances and the mesh stiffness of the internal spur gear pair. The results show that tooth profile shift has an obvious influence on the mean value, amplitude variation and phase of the mesh stiffness, from which it can be predicted that the dynamic response of an internal gear transmission system will be affected by the tooth profile shift.

汽车领域人工智能应用探讨

人工智能技术的发展推动着全球各行业的技术革新。目前汽车行业的蓬勃发展离不开人工智能技术的融合应用,主要包括2个方面:在汽车制造中,生产线设备维护、故障检测、智能仓储物流等智能化系统;在车载系统中,智能汽车电子、自动驾驶技术、ADAS车辆行驶状态检测等。基于此,主要对人工智能技术在汽车制造与车载系统中的应用加以分析。研究数据表明,与传统技术的汽车生产相比,融合人工智能技术的汽车生产安全性提高了11.6%,返工率降低了5.0%,故障平均检测时长缩短了15 min。展望了未来人工智能在汽车自动驾驶方面的机遇和以及安全防盗、算力不足的挑战,为推动智能汽车发展提供参考。

Shifting Into a New Gear

China plans to build and sell 5 million hybrid and electric cars by 2020 and is promoting their use The Ministry of Industry and Information Technology(MIIT)is drafting a 10-year plan from 2011 to 2020 for the development of energy-efficient and new energy cars.

混合动力汽车无同步器AMT主动同步控制策略

以混合动力商用车电控机械式自动变速器(Automated Mechanical Transmission,AMT)换挡过程为研究对象,以减小换挡冲击和缩短换挡时间为目的,使用Simulink搭建了包含动力源动态协调与基于最优控制原理的电动机主动同步控制的无同步器换挡控制模型,并使用AMESim建立了动力系统及整车动力学仿真模型;以5挡升至6挡为例,采用AMESim与Simulink开展联合仿真分析,并与传统换挡策略的换挡性能进行了对比。仿真结果表明,换挡过程中,同步时间缩短21.42%,最大冲击度减少24.88%,整个换挡时间缩短18%。最后,基于dSPACE半实物仿真平台对所提控制策略进行了实时验证。

Gear downshift control of inverse-automatic mechanical transmission of electric vehicle

In order to improve the driving dynamics and riding comfort of pure electric vehicles,taking a two-speed I-AMT(Inverse-Automatic Mechanical Transmission)with rear friction clutch as the research object,a gear shift strategy,which consists of the open-loop control of the clutch position control and the closed-loop control of the drive motor speed control,is proposed.Considering the inherent time-delay and external disturbances within the motor speed adjustment system,a two DOF(degree-of-freedom)Smith predictor with feedforward input is designed to track the target speed of the drive motor.The feedforward input is used to eliminate the influence of clutch sliding friction on the motor speed control,while the feedback speed tracking controller is applied to realize the speed tracking performance with the existence of time-delay and the external disturbance.In order to verify the effectiveness of the gear shift control strategy and the accuracy of the two DOF Smith controller with feedforward control,simulation results comparison is firstly carried out to illustrate the effectiveness of the control scheme.Then,a light pure electric vehicle equipped with I-AMT was used for downshift experiments under large throttle,which is the most difficult working scenario to control the transmission.The experimental results show that the two DOF Smith controller can eliminate the influence of time-delay on the closed-loop control,and the proposed whole gear shift control strategy can limit the clutch slippage time within 1.5 s,resulting in a smaller shift jerk,thus guarantee the driving dynamics and riding comfort simultaneously.

大型水运枢纽船舶闸室连续排挡模型及算法研究

为提高内河通航设施船舶通航效率,提高通航设施工作能力,提出一种可以求解考虑船舶顺序入闸和不考虑船舶顺序入闸两种情况的船舶闸室连续排挡模型和算法。利用二维装箱问题模型建立船舶闸室连续排挡模型,采用贪婪策略思想,提出船舶闸室连续排挡模型求解算法。根据百色枢纽工程生成仿真到闸船舶船型数据,用算法进行闸室排挡计算。结果表明,在随机生成90艘船舶的情况下,考虑船舶到闸顺序的排挡结果需要使用47个闸次,闸次平均占用率为76.424%,不考虑船舶到闸顺序的排挡结果需要使用45个闸次,闸次平均占用率为76.821%,模型和算法能够对不同情况下船舶闸室进行有效连续排挡。

基于扭矩预测的拖拉机动力换挡修正策略

为了解决挡位密集的拖拉机在负载变化的情况下容易出现频繁换挡,提出了一种对负载扭矩预测和考虑驾驶员意图的挡位修正策略。基于AMESim和Matlab/Simulink联合建立仿真模型,设计了基本换挡和挡位修正2种仿真方案。仿真结果表明,经过挡位修正模块修正的换挡策略减小了换挡频率并避免了换挡循环,降低了拖拉机作业速度波动,提高了拖拉机的作业质量,降低了燃油消耗量,提高了燃油经济性。

新型插电式混合动力客车换挡控制策略的分析

提出了一种新型插电式混合动力变速器并分析其换挡模式。基于AMESim仿真软件建立新型混合动力变速器模型,分析和制定换挡控制策略,设计测试用例并在MATLAB/Simulink中搭建整车模型。仿真测试结果表明,该新型混合动力装置对换挡冲击的控制效果良好,换挡品质好,可实现动力无中断、平滑换挡,满足控制策略要求。对提升城市新能源客车换挡品质及节能环保等方面具有现实意义。

基于加速度反馈的电机快速换挡方法

商用车在换挡过程中,会出现短暂的动力中断,电机的调速时间直接影响动力中断时间。而动力中断时间决定了换挡的品质,文章提出了一种基于微分负反馈的变速器快速换挡方法,对驱动电机的转速反馈进行微分处理,从转速反馈信息中提取转速变化量的信息。然后经过比例积分控制器调节,输出指令扭矩,从而实现驱动电机的快速转速调节。

驱动系统效率最优的并联混合动力商用车模式切换及换挡控制策略

为提高搭载自动变速器的并联混合动力商用车燃油经济性,以驱动系统效率最优为目标,提出一种新的驱动模式边界划分和挡位边界划分方法。制定了基于效率最优的模式切换及换挡控制策略,并在中国重型商用车行驶工况下对所制定的控制策略进行了仿真验证。结果表明,所提出的策略不仅能够维持电池荷电状态的平衡,且百公里油耗比电辅助控制策略低11.2%,具有更好的燃油经济性。

基于AVL-DRIVE系统的乘用车双离合变速器换挡品质评价分析

为了解决搭载双离合变速器车辆在低速行驶状态下易出现顿挫现象的问题,提升动力响应能力以及换挡品质,本文以某款双离合变速箱乘用车为研究对象,基于AVL-DRIVE驾驶性评价系统,在不同驾驶模式下对其进行换挡测试。结果表明,不同的驾驶模式下换挡品质存在较大差异,针对评分较低的项目进行分析并提出优化策略,为汽车制造商改进整车品质提供可靠依据。