【作者】 刘玺；

【导师】 程秀生；

【作者基本信息】 吉林大学 ， 车辆工程， 2011， 博士

【摘要】 随着车辆自动操纵技术的迅速发展,自动变速器呈现蓬勃发展的趋势,自动变速器性能的充分发挥可使整车具有降低燃油消耗率、改善排放、提高动力传动系统使用寿命及减轻驾驶者劳动强度等优点,因此得到了越来越广泛的应用。双离合器自动变速器(Dual Cluth Transmission,简称DCT)是一种新型自动变速器,它是在平行轴式变速器基础上发展而来,将奇、偶数档位分别布置在两个离合器上,通过两个离合器交替实现换档。它既保持了传统手动变速器结构简单、机械效率高等优点,又能实现动力无中断换档,提高车辆动力性和经济性,改善换档品质。因此近年来DCT已成为国际变速器领域研究开发的热点。本文基于国内外DCT研究现状,结合国家“863”高技术研究发展计划资助项目“6档双离合器自动变速器开发”,对湿式双离合器自动变速器换档过程关键技术进行了深入研究,主要研究内容如下:(1)在分析了湿式双离合器自动变速器电液系统组成和原理基础上,对DCT换档过程中的电液系统相关电液阀特性进行了分析与建模仿真,并进行了试验验证,仿真结果和试验数据能够较好的吻合。(2)对DCT预选档过程的预选档特性和换档力控制技术进行了研究,并针对换档力控制技术,对同步器工作过程进行了分析,在此基础上建立了同步过程数学模型和预选档过程换档阻力模型,并对预选档过程换档拨叉的目标位置及该位置对应的换档力进行了研究。在此基础上,进行了整车试验,验证了所制定的换档力模糊控制策略的有效性,对改善DCT换档品质有实际意义。(3)对DCT换档过程离合器控制的最佳目标扭矩确定方法进行了研究。在对双离合器自动变速器不同工况的换档过程进行分析的基础上,制定了分阶段换档策略,建立了各阶段换档动力学模型。根据二次型最优控制理论,结合换档品质评价指标,选定滑磨功和冲击度作为二次型性能指标函数,建立了换档过程的状态空间模型,依此求得换档过程各个阶段的离合器最优目标扭矩,并结合试验车参数进行了不同权重系数的换档过程仿真,通过仿真对比,表明了通过调整权重系数,可以使滑磨功和冲击度得到有效平衡,通过运用基于二次型最优的DCT换档过程离合器目标扭矩决策技术可以获得较好的换档品质。(4)对DCT换档过程的湿式离合器压力控制方法进行了研究。在对湿式双离合器结构、工作原理和扭矩传递特性进行分析的基础上,建立了湿式离合器扭矩模型,为湿式离合器基于数学模型的控制奠定基础。鉴于数学模型控制中精确度不足及长期使用后性能改变的问题,将PSD控制算法引入到单神经元PID控制中,形成单神经元自适应PSD智能控制器并应用到湿式离合器控制系统中,建立离合器压力智能控制算法并进行整车试验,试验结果表明基于单神经元自适应PSD的湿式离合器控制算法跟随性好,控制精度高,使车辆具有较好的换档特性。(5)在分析驾驶员类型基础上,进行了有关DCT换档过程中基于驾驶员类型的DCT换档规律及其确定方法的研究。采用BP神经网络分类器对驾驶风格进行辨识,再采用贝叶斯融合决策方法先后对同类操纵的驾驶风格辨识结果和所有操纵类型驾驶风格辨识结果进行了数据融合决策,最终辨识出驾驶员类型。根据驾驶员类型,制定了基于驾驶员类型的DCT换档规律,通过对不同驾驶员类型的DCT换档规律仿真对比,表明了基于驾驶员类型的DCT换档规律能够适应不同类型的驾驶员需求。本文通过理论分析与试验研究相结合的方法,对湿式双离合器自动变速器换档过程关键技术进行了深入研究,试验结果表明获得了较好的换档品质,对湿式双离合器自动变速器换档技术的开发具有一定的参考价值。更多还原

【Abstract】 With the rapid development of automatic control technology, automatic transmission has been developing vigorously. It has the virtues of reducing fuel consumption, improving emissions, enhancing the life of driveline and relieving labour intensity of drivers etc. Thus, it has been applied more and more frequently.Dual clutch transmission is a new type of transmission. It is based on the parallel axis type transmission. Odd and even gears are respectively arranged with two clutches and shift by exchanging the two clutches. It not only maintains the merits of simple structure, low cost and high mechanical efficiency compared with conventional manual transmission, but also attains shifting without power interruption, and improves power performance, fuel economy and shifting quality. So in recent years, DCT has been a focus of the research in the field of international transmission.This paper is based on the current situation of the research on DCT, combining with the national 863 Science Plan of China-Imlpementing Scheme on "the development of six-speed dual clutch transmission".The key technologies during the shifting process of wet dual cluth transmission are studied. The main contents of research are as follows:(1) Based on the analysis of the functions, compositions and operation principles of electrohydraulic system, the hydraulic characteristics of shifting force control and clutch pressure control are studied. The models of shifting force control module and clutch pressure control valve are established and simulations are carried out. And solenoid valve test is conducted on a hydraulic pressure colligation test-bed, the test results show that the simulating outcomes are in coincidence with the experimental data, reflecting the basic properties of electromagnetic pressure control.(2) Characteristics of pre-select gears and control technology of shifting force are researched. Mathematical model of synchronous process and resistance model of pre-select gears process are established based on the working process of synchronizer. The target position of shifting fork in the process of pre-select gears and the shifting force corresponding to the position are determined. The fuzzy control strategy of shifting force is proved to be effective by the vehicle test. (3) The determination method of cluth optimum target torque in the shifting process is studied. Staged shift strategy is formulated and shifting dynamical models in different stages are established based on analysis of dual clutch transmission in the shifting process of different working conditions. An optimal control trajectory of clutch pressure at every shift stage is obtained by optimal control algorithm in which longitudinal jerk and friction work are chosen to form quadratic performance index functions, and the optimal control of clutch pressure in the shift process is realized using optimal control trajectories. Jerk and friction during shifting process can be well equilibrated by adjusting weight coefficients.(4) The structure of wet dual clutch, its operating principles and torque transfer characteristics are analysed, then the troque model of wet clutch is established based on the analysis. Considering the accuracy of mathematical control model is not precise enough and the quality change after using for a long time, PSD control arithmetic is introduced into the single neuron PID control, and the single neuron adaptive PSD intelligent controller is formed and applied into wet clutch control system. The clutch pressure intelligent control algorithm is built and the real vehicle tests are done. Test results show that the wet clutch control arithmetic based on the single neuron adaptive PSD possesses good following performance and high control precision. Based on the optimal theory of the clutch target torque, the determination technique keeps slipping work and jerk well balanced and supplies the vehicle with good shift characteristics.(5) The DCT shift schedule based on driver type is studied. After identifying the driving style with BP neural network classifier, the data fusion decision is made based on the driving style identification result of manipulation and the driving style identification result of all different manipulation with bayesian fusion decision method, and the driver type is identified in final. DCT shift schedule based on driver type is established with the identification result, and the simulation is carried out. The validity of the shift schedule is verified by the simulation results.In this paper, the key technologies during the shifting process of wet dual cluth transmission are studied by theoretical analysis associated with experimental research. The results show that a good shifting quality is achieved, which has some reference value to the shifting technology development of wet dual cluth transmission.更多还原