Simulation study on starting of dual clutch transmission for tracked vehicles

In order to study the application of dual clutch transmission （DCT） on tracked vehicles, a simulation moclel and two control methods were performed for starting analysis. Based on a certain transmission of an existing tracked vehicle, a DCT structure was proposed. Matlab/Simulink was a dopted as a platform to develop the simulation model. The engine speed was controlled to follow the target speed as a launch strategy. Two control methods, a proportional integral derivative （ PID ） control method and a fuzzy control method, were proposed to control the engine throttle and oil pressure in order to track the target engine speed. Simulation results show that either the PID control or fuzzy control method can improve the starting performance compared with no loop control meth od. Fuzzy control method can lead a better starting quality compared with PID control method.

Developing Additive Technology for Wet Dual Clutch Transmissions

Wet dual clutch transmissions(W-DCTs) show overall benefits including excellent fuel efficiency,wide torque capacity range,long durability,driving comfort and sportiness.Many breakthroughs have been made to further improve the fuel efficiency by design innovations and introductions of new hardware.Each W-DCT has its unique design and hardware.It demands the lubricant to provide excellent wet clutch friction performance and anti-shudder friction durability,good synchronizer friction performance and durability,high load-carrying ability,excellent bearing performance,strong anti-corrosion performance,high thermal and oxidative stability,excellent material compatibility,etc.Particularly,the requirement of the wet clutch friction performance in W-DCT is much more severe than conventional ATFs and CVTFs.We report here our latest W-DCTF technologies developed for different W-DCT applications.DCTF-1 was optimized for a two-sump W-DCT application with the clutch lining material of friction material A(FM-A).DCTF-1 shows high and stable dynamic friction,static friction,particularly,high quasi-static friction without any shudder tendency in GK tests.DCTF-2 was designed for a one-sump W-DCT application with the same clutch lining material of FM-A.DCTF-2 completes 42,000 cycles of the severe GTI chassis dynamometer vehicle test without any issues,which is comparable to the factory fill fluid DCTF-FF.DCTF-3 was developed for a one-sump W-DCT application with a different clutch lining material of FM-B.DCTF-3 shows high and stable dynamic friction in the severe newly developed SAE DCT test procedure.DCTF-3 also gives excellent LVFA durability of over 720 h in the JASO M349 test procedure on FM-B.

Design of Multi-domain Collaborative Simulation System for Dual Clutch Transmission Based on CAN Bus

A multi-domain collaborative simulation(MDCS) system for dual clutch transmission(DCT) was presented based on controller area network(CAN) bus.An interface card of CAN bus was designed,in which MDCS subsystems were linked as the nodes according to the interface mode of MDCS.A DCT simulation model was established based on Matlab/Simdriveline,whose running process was accurately controlled by the designed control system.The playback system of vehicle state(VPS) was proposed whose input was the road-test data,with a real vehicle test environment for the development of transmission control unit(TCU) being provided.A DCT kinematic system model was set up,and the running status of DCT parts could be displayed in real time.The functions of MDCS were verified based on the extra-urban driving cycle(EUDC) and the vehicle road-test data respectively.The results show the functions of MDCS are accomplished,and the unified supporting platform for the development of TCU is achieved by MDCS.

Strategy to control crawling vehicles with automated mechanical transmission

In order to move vehicles with automated mechanical transmission （AMT） a little bit of distance, such as reversing into or moving in a garage, a control strategy for crawling vehicles was proposed. Based on the dynamic analysis of vehicle starting process and requirements of crawl driv- ing for the vehicle, a control strategy of the clutch was designed. The strategy increased the.slipping friction torque first and then decreased it, in order to realize the crawl driving. The speed increased by the engagement of the clutch, and then the clutch turned to disengage to the half disengage point, when the speed met the requirements. Based on the control strategy, a control software was de- signed. In the end, the software was tested on a vehicle with AMT. The lowest steady vehicle speed was reduced to 40% of the original value, which was set in the control strategy.

考虑离合器摩擦性能衰减的湿式DCT车辆起步控制研究

建立了考虑离合器摩擦系数变化及离合器性能衰减的湿式双离合变速器(dual clutch transmission,DCT)车辆起步过程动力学模型,以车辆起步过程冲击度、滑摩功和起步滑摩时间为优化目标,采用线性二次型最优控制方法获得了车辆起步过程离合器最优传递转矩。针对离合器摩擦系数变化及离合器性能衰减对车辆起步过程离合器压力控制的影响,提出了一种离合器压力非线性鲁棒控制策略,以实现对离合器最优传递转矩的跟踪。结果表明,所提出的非线性鲁棒控制策略能够在离合器摩擦系数变化的情况下实现对离合器最优传递转矩的有效跟踪,跟踪误差不大于0.02 N·m,且能够适应摩擦性能衰减导致不同寿命阶段摩擦系数的不同变化规律,与比例-积分-微分(proportion-integral-differential,PID)控制策略相比具有更精确的控制效果和更强的鲁棒性。

双离合器变速箱换挡集成学习控制器设计及分析

为了提高车辆运行的稳定性,设计了一种双离合器DCT变速箱换挡集成学习控制器。基于预测模型建立MPC控制器,以补偿转矩保障转速精准追踪。研究结果表明,在0.11 s时DCT开始出现升挡转矩相,车速整体维持稳定变化的态势,车辆冲击度的最大值是4.8 m/s^(3),有利于大大提高换挡的稳定性。相比其他控制方法,基于经验知识MPC换挡方案获得更优的平顺性控制效果,滑摩功也发生降低,可以更快完成动力响应。该研究有助于提高汽车自动控制,为后续的换挡控制奠定理论基础。

预选挡对双离合变速器敲击动力学影响的试验研究

搭建可模拟发动机转速波动的变速器敲击动力学试验台架,采集双离合变速器(dual-clutch transmission, DCT)的壳体振动和齿轮瞬时转速信号,研究不同预选挡位下DCT变速器的敲击响应和齿轮系统动力学随输入角加速度幅值变化的演变规律。根据齿轮系统间隙非线性动力学模型的计算结果和齿轮啮合基本定律,提出了一种基于齿轮特征频率角加速度幅值特性的齿轮运动状态判定准则。台架敲击试验结果表明预选挡显著改变DCT变速器的敲击响应和齿轮副动力学行为,当输入角加速度幅值增加到某一数值时,DCT变速器敲击响应发生向上跳跃现象,主动和被动子变速器之间产生明显的低频动力学耦合,承载齿轮转速信号呈现显著的多谐波非线性特性。根据提出的齿轮运动状态判定准则判断跳跃突变后的承载齿轮副发生齿面分离和敲击现象,动力学突变后的动力学耦合导致DCT变速器的敲击响应急剧恶化。最后,在整车上验证了台架试验的动力学耦合和敲击响应突变现象。

基于液压系统的自动挡变速器的故障分析与处理

本文阐述了自动变速器液压驻车系统的工作原理,利用CANape软件对双离合器自动变速器由液压驻车系统和液压控制模块引起的常见的故障进行详细分析,并针对故障提出可行的解决措施,为解决自动挡变速器常见故障等问题提供了理论和实践依据。

MPC-Based Downshift Control of Automated Manual Transmissions

Automated manual transmissions,which usually adopt synchronizers to complete the gear shift process,have many advantageous features.However,the torque interruption and the challenging control objectives during the gear shift process limit its industrial application,especially for the power-on gear downshift.This paper proposes a model predic-tive control(MPC)method to control the clutch engagement process and effectively shorten the torque interruption,consequently enhancing the gear downshift quality.During the control law deduction,the proposed MPC also accounts for time-domain constraints explicitly.After the control law was deduced,it was validated through simulations under two typical power-on gear downshift working scenarios.Both of the simulation results demonstrate that the controller proposed in this paper can shorten the torque interruption time during power-on gear downshifts while minimizing vehicle jerk for overall satisfactory drivability.

基于灰色关联和模糊理论的双离合变速器车辆起步品质评价

针对目前双离合变速器(DCT)车辆起步评价以驾驶员主观评价为主,主观性过强导致评价不准确的问题,基于灰色关联分析法和模糊综合评价法建立了DCT车辆起步品质评价体系。考虑动力性、舒适性和经济性,选取起步响应延迟时间、起步加速时间、起步加速度峰值、发动机转速波动以及冲击度作为评价指标;使用变异系数法计算了各指标的客观权重,并基于灰色关联分析法明确了各指标与起步品质的关联度排序,验证了权重计算结果的准确性与可靠性;最后,基于模糊综合评价法建立起步品质评价模型并进行客观评分,使DCT车辆的起步品质评价更加客观真实。

P2.5-PHPS发动机至混合驱动模式切换过程动态协调控制研究

搭载双离合变速器的P2.5插电式混合动力系统传动效率高,换挡和模式切换过程无动力中断,应用前景广阔,但其模式切换过程由于发动机与电机的扭矩响应特性存在差异,扭矩波动明显,影响驾乘体验。针对上述问题,提出一种发动机驱动至混合驱动模式切换的协调控制策略,以搭载双离合变速器的P2.5插电式混合动力系统为研究对象,对其发动机至混合驱动模式切换过程进行分析,依据分析结果将系统模式切换过程划分为4个阶段。在此基础上,基于PID反馈原理控制动力源的实际输出转矩并通过控制加速踏板开度变化率限制发动机的扭矩变化率,利用驱动电机扭矩快速响应的优势补偿发动机扭矩响应滞后来降低输出扭矩波动,制定模式切换过程多阶段双动力源扭矩协调控制策略。搭建基于P2.5插电式混合动力系统的发动机至混合驱动模式切换动态协调控制仿真模型。仿真结果表明,模式切换过程无动态协调控制策略的最大冲击度约7.1 m/s^(3),策略下最大冲击度约1.78 m/s^(3),减小74.9%,表明所提出的控制策略能有效减小模式切换过程冲击度,提高整车平顺性。

双离合变速器动力系统加速工况扭振和敲击的被动控制措施研究

为研究不同预选挡机制下的双离合变速器敲击特性和控制方法,分别在整车和敲击台架上评价变速器的敲击主客观表现和随角加速度变化的敲击灵敏度;其次,根据敲击灵敏度,整车扭振响应和敲击主客观结果的相关性提出了一种定量评价变速器输入轴角加速度的无敲击扭振阈值。在相同整车上分别评价不同扭振和敲击的被动控制措施,包括离合器式扭转减振器,双质量飞轮式扭转减振器,以及离合器微滑摩和离心摆吸振器与扭转减振器的组合方案。台架试验结果表明预选挡显著改变双离合变速器的敲击特性,在某一激励幅值时产生敲击突变现象。整车试验结果表明离合器式和双质量飞轮式扭转减振器无法满足双离合变速器加速工况无敲击扭振阈值要求,在低转速段产生明显敲击;离合器微滑摩和离心摆吸振器与扭转减振器组合方案的输入轴角加速度幅值满足无敲击扭振阈值要求,消除了双离合变速器动力系统存在预选挡时的加速敲击。

考虑DCT车辆起步过程离合器接合稳定性的双质量飞轮参数优化

在车辆起步过程中,发动机输出转矩波动会导致离合器接合不稳定,从而影响整车动力传动系统的平顺性。双质量飞轮(dual mass flywheel,DMF)可减小发动机转矩波动对离合器及整车动力传动系统的影响。针对起步过程离合器接合不稳定影响整车平顺性的问题,以双离合器自动变速器(dual clutch automatic transmission,DCT)车辆为研究对象,研究了DMF的刚度、阻尼和初级与次级飞轮惯量比对DCT车辆起步过程离合器接合稳定性的影响,并建立了以离合器黏滑比和整车冲击度为目标函数的多目标优化模型,利用遗传算法对模型进行优化,得到了使离合器接合稳定性提高且整车冲击度明显降低的DMF最优参数组合。

基于可解释极端随机树模型的DCT液压响应预测

为解决传统湿式双离合器变速器(Dual Clutch Transmission,DCT)控制策略在硬件误差以及复杂工况下液压响应预测精度不完全可控的问题,提出了一种基于SHAP图可解释极端随机树预测模型,使用机器学习方法结合某汽车公司DCT实验室采集的真实离合器数据对DCT液压响应进行预测。模型利用SHAP算法对于重要特征选择的可解释性,筛选并保留对液压响应影响较大的特征,将时间切片和升降压判定作为特征加入训练数据,训练预测模型。结果表明,该模型训练结果的均方误差MSE为0.6703,可决系数R2为1.0000,并且在测试集上预测值与实际值之间的平均误差为12.99 kPa,远低于设计误差25 kPa,具有较高的预测精度,特征选择较准确,可以很好地解决传统物理模型无法计算不同工况下液压响应的问题,为下阶段基于数据和物理双驱动的DCT控制策略优化提供较准确的预测结果。

双离合自动变速箱起步过程控制策略研究

为提高搭载双离合自动变速箱车辆起步瞬间的动力响应性和起步过程的平顺性,提出了一种新的起步控制策略。采用目标转速控制方法,在起步过程分别对发动机和离合器扭矩进行控制,两者结合以实现起步动力响应的快速性和起步过程的平稳性。最后通过Simulink建模,生成代码下载到变速箱控制单元(TCU)中,通过客观评价测试系统对新的控制策略进行实车测试验证。测试结果表明,该新控制策略客观得分较高,不但能够实现起步瞬间动力响应的快速性,而且能够实现起步过程发动机转速稳定,满足车辆起步的平顺性以及动力响应性要求。

变速器EOL测试偶数输入轴拖曳转速过高问题分析

某双离合变速器总成在开发阶段End Of Line(EOL)下线测试时,由于偶数输入轴拖曳转速过高,导致偶数离合器Kiss Point(KP)点学习失败,最终影响变速器总成EOL的一次合格率。基于EOL下线测试方法及评价准则,结合此双离合变速器的结构特点,分析产生拖曳扭矩的零件,通过总成有限的ABA互换零件方式锁定产生拖曳扭矩的主要影响因子,最终调整零件加工尺寸的合理范围实现偶数输入轴拖曳转速降低,提升变速器总成EOL下线的一次合格率。

基于响应曲面法的齿轮轴高精磨削加工参数优化研究

针对某变速器发生异响展开研究,锁定问题发生的根本原因是圆度不合格,进而将故障发生时间锁定在齿轮轴的外圆高精磨削加工过程中。识别出5个对圆度影响显著的因子。通过中心复合响应曲面方法设计出因子及因子的水平,利用Minitab软件,生成108次随机试验矩阵。对108次试验结果进行分析发现,模型一阶项、二阶平方项对异响的影响显著,二阶交互的作用不显著。通过残差分析验证了模型符合假设,进而得到模型回归方程的最优解。同时,基于模型,调整了因子参数,缩短了加工时间,提升了生产效率,解决了高精磨削加工过程中的圆度不合格问题。研究表明,该方法可以识别出模型中弯曲、非线性关系,进而得到全局最优。同时,所建立的模型为零件加工过程参数调整提供了依据。

双离合变速器后壳体压铸件的快速开发

首先基于压铸理论对铝合金双离合变速器后壳体进行初始压铸工艺设计,然后运用MAGMASOFT?模拟软件对铸件初始压铸工艺进行模拟,根据模拟结果分析了铸件可能产生缺陷的位置及原因,并对此初始工艺进行改进优化,最后依据最优工艺条件设计模具并试制生产铸件。实际生产验证表明,试制铸件状态与模拟结果基本吻合,采用模拟软件辅助设计,突破了传统的铸造技术局限,大幅度缩短了工艺定型周期,减少了实际生产中模具调试和更改的次数,实现了复杂铸件快速开发的目的。

双离合器式自动变速器换挡特性研究

介绍了双离合式自动变速器工作原理 ,建立了换挡过程的数学模型 ,并对升、降挡的换挡特性进行了仿真与试验分析 。

双离合器式自动变速器控制系统的关键技术

从离合器起步时的动力学模型、离合器接合速度的控制策略及离合器执行机构的跟踪品质三个方面,总结双离合器式自动变速器(Dual clutch transmission,DCT)起步控制技术的发展现状,提出进一步优化DCT起步性能的途径。将目前的换挡规律分别归纳为基于经验、基于约束条件、智能修正和综合智能四种类型,总结各种换挡规律的应用现状,提出进一步完善综合智能换挡体系的方法。总结改善DCT换挡品质的研究成果,提出进一步提高换挡品质的方法。总结数字仿真在DCT研发中的应用现状,分析半实物仿真在DCT控制系统研发中的应用方法。