COT式自动变速器及其换挡特性与控制研究

发布时间：2018-07-23 20:24

【摘要】：变速器是汽车的关键部件,在常规动力、混合动力及纯电动汽车中均发挥了至关重要的作用。长久以来,自动变速器始终处于汽车技术创新的最前沿,从早期的三/四挡AT、五挡AMT,发展到现在的九/十挡AT、七/八挡DCT,自动变速器的发展极大地推动了汽车技术进步。本文提出了一种采用摩擦离合器和超越离合器配合换挡的离合-超越自动变速器(Clutch and Overrunning Clutch Transmission,简称COT),运用系统动力学方法,建立了传动系模型,分析了变速器的换挡特性,提出了换挡控制策略,进行了仿真计算和台架试验研究。具体工作如下:首先,开展了CST类自动变速器的结构方案研究。为减少自动变速器中摩擦离合器的数量,提出了基于知识网络和TRIZ理论的知识创新方法,将该方法应用于自动变速器结构知识创新中,产生了一类仅采用一个摩擦离合器实现全部挡位无动力中断换挡的自动变速器——CST(Clutch and Mechanical Switch Transmission)。CST分为两个子类:采用离合-超越方式换挡的COT和采用离合-牙嵌方式换挡的CDT(Clutch and Dog Clutch Transmission)。通过对四种形式的CST进行结构布置及部分关键零部件的三维结构建模,说明CST具有成为自动变速产品的结构可行性。其次,进行了COT换挡过程的动力学特性分析。以COT机构原型为研究对象,建立了传动系动力学模型,推导了变速器升挡和降挡过程的动力学方程,建立了发动机的转矩计算模型、湿式离合器的转矩计算模型、超越离合器的转矩计算模型及整车阻力矩的计算模型。运用AMEsim软件搭建了整车动力学仿真模型,进行了升挡和降挡仿真计算。在仿真研究的基础上,进一步分析了这种变速器换挡时的动力学基本特性,进而得到了这种变速器的换挡共同特征,即换挡时无动力中断、换挡迅速和换挡时存在转矩冲击。然后,进行了超越离合器接合冲击的计算方法研究。针对COT降挡过程中超越离合器自动接合会对系统带来转矩冲击的问题,采用超越离合器-超越离合器换挡试验台进行了台架试验。运用牛顿力学方法分阶段建立被测对象的动力学模型,运用显式动力学有限元方法获得超越离合器接合产生的冲击激励,将超越离合器接合产生的激励和传动系输入转矩的激励叠加,计算得到变速器输出端的转矩和转速响应,并与实测值进行对比。理论和试验结果共同显示,输入转矩一定的情况下,输入转速对超越离合器接合冲击大小没有影响,输入转速只对传动系转矩变化率和换挡时间产生影响。再后,进行了COT的换挡控制研究。搭建了变速器控制器的整体架构,进行了控制策略底层、中层和上层的三个层级划分。分析了COT换挡过程的关键控制问题,以换挡特性分析结果为基础,制定了COT升挡和降挡控制策略。仿真结果显示,升挡与降挡控制策略均使得换挡冲击度绝对值下降到10 ms-3以内,与未加控制时的仿真结果(升挡15.5 ms-3,降挡24.8 ms-3)相比,换挡品质有明显改善。进一步,在对换挡过程状态方程进行了正则化线性处理的基础上,采用模糊滑模变结构控制方法开发了换挡控制器,并进行了模糊滑模变控制方法与PID控制方法的对比仿真。仿真结果显示,模糊滑模变结构控制具有更高的控制精度及更好的抗干扰能力。最后,开展了COT的台架试验研究。搭建了用于验证COT换挡特性及换挡控制的两挡试验台架,进行了升降挡试验。试验结果显示,升挡时间为0.7 s,驱动降挡时间为0.5 s,说明COT换挡迅速,与前述换挡特性研究结果吻合。升挡与降挡控制试验结果分别比未施加控制时的传动系转矩冲击降低了72.2%和76.2%,说明换挡控制策略有效。论文的研究工作为COT的推广应用做了技术准备,为自动变速器行业提供了新的自动变速器形式,也为更多新型自动变速器的产生提供了完整的理论参考。
[Abstract]:Transmission is the key component of the car, which plays a vital role in conventional power, hybrid and pure electric vehicles. For a long time, the automatic transmission has always been in the forefront of automotive technology innovation, from the early three / four block AT, five block AMT, to the present nine / ten block AT, seven / eight block DCT, and the development of automatic transmission is great. In this paper, a kind of Clutch and Overrunning Clutch Transmission (COT) is put forward by using friction clutch and overrunning clutch, and the system dynamics method is used to establish the transmission model. The shift characteristic of the transmission is analyzed and the shift control is put forward. The strategy, simulation calculation and bench test are carried out. The specific work is as follows: first, the structure scheme of CST type automatic transmission is studied. In order to reduce the number of friction clutch in automatic transmission, a knowledge innovation method based on knowledge network and TRIZ theory is put forward, and this method is applied to the knowledge innovation of automatic transmission. A kind of automatic transmission, CST (Clutch and Mechanical Switch Transmission).CST, is divided into two subclasses: COT with outlier transcendent mode and CDT (Clutch and Dog) by outlier mode (Clutch and Dog). The structure layout of the four forms of CST and the three-dimensional structure modeling of some key parts show that CST has the structure feasibility of becoming the automatic transmission. Secondly, the dynamic characteristics of the COT shift process are analyzed. The dynamic model of the transmission system is established with the prototype of the COT mechanism, and the lifting gear and the drop of the transmission are derived. The dynamic equation of the process, the torque calculation model of the engine, the torque calculation model of the wet clutch, the torque calculation model of the overrunning clutch and the calculation model of the resistance moment of the whole vehicle are set up. The simulation model of the whole vehicle dynamics is built with the AMEsim software, and the simulation calculation of the lifting and reducing gear is carried out. On the basis of the simulation research, the simulation of the engine is carried out. The basic dynamic characteristics of the gearshift are analyzed in one step, and then the common characteristics of the gear shift are obtained, that is, no power interruption, rapid shift and torque impact when shifting. Then, the calculation method of the joint impact of the overrunning clutch is carried out. In the process of COT falling gear, the overrunning clutch is automatic. The joint will bring the torque impact to the system, and use the overrunning clutch and overrunning clutch shift test bench to carry out the bench test. Using the Newton mechanics method, the dynamic model of the measured object is set up by the Newton mechanics method. The dynamic finite element method is used to get the shock excitation of the overrunning clutch joining, and the overrunning clutch is joined together. The generated excitation and drive system input torque excitation superposition, calculated the torque and speed response of the transmission output end, and compared with the measured values. Theory and test results show that the input speed has no effect on the engagement impact of the overrunning clutch when the input torque is certain, and the input speed is only to the transmission torque. The change rate and shift time have an impact. Then, the shift control of COT is studied. The overall architecture of the transmission controller is built. Three levels of the control strategy, the middle layer and the upper layer are divided. The key control problems of the COT shift process are analyzed. Based on the analysis results of the shift characteristics, the COT lifting and reducing control is formulated. The simulation results show that the control strategy of lifting and falling gear decreases the absolute value of the shift impact to less than 10 MS-3, and the shift quality is obviously improved compared with the simulation results (15.5 MS-3 and 24.8 MS-3) without control. The shift controller is developed with fuzzy sliding mode variable structure control method, and the comparison simulation between fuzzy sliding mode control method and PID control method is carried out. The simulation results show that the fuzzy sliding mode variable structure control has higher control precision and better anti-interference ability. Finally, the platform test research of COT is carried out. The model is used to verify the CO. The T shift characteristic and the shift control two gear test bench have carried out the lifting and lifting test. The test results show that the lifting gear time is 0.7 s and the drive down time is 0.5 s, which indicates that the COT shift is rapid, which is in accordance with the previous shift characteristic research results. The test results of the lifting gear and the gear reduction control are reduced by 72 respectively than that of the transmission system without the control. .2% and 76.2% show that the shift control strategy is effective. The research work of this paper makes technical preparation for the popularization and application of COT. It provides a new form of automatic transmission for the automatic transmission industry, and provides a complete theoretical reference for the production of more new automatic transmission.
【学位授予单位】：华南理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：U463.2

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