【作者】 吴军；

【导师】 薛殿伦；

【作者基本信息】 湖南大学 ， 机械工程， 2012， 硕士

【摘要】 在当今社会，汽车已经成为人们生活中很重要的一部分，人们不再仅仅重视汽车的经济性和动力性，对汽车的驾驶舒适性也提出了更高的要求，特别是轿车进入家庭，私人司机的大量出现，对自动挡汽车的需求日益迫切。金属带式无级自动变速器(CVT：Continuously Variable Transmission)因其具有结构简单、操纵方便、传动效率高、节能和环保等优点，作为一种理想的变速装置成为人们的首选，近几年得到快速的发展。因此本文研究中选择金属带式无级变速器作为研究对象，并针对复杂路面情况，提出了综合控制策略工作模式，以兼顾经济性和动力性的需求。本文首先在查阅了大量资料的基础上，对金属带式无级变速器经济性、动力性、传动效率、可靠性与寿命、排放和成本等方面的优势及其在国内外发展状况以及未来的发展趋势进行了论述。其次，根据金属带式无级变速器的结构对其工作原理进行了分析，并详细分析了金属带式无级变速传动的控制技术，为后面的建模与仿真提供了很好的理论基础。再次，对影响CVT控制性能的电液系统进行了比较分析，并着重分析电控系统，包括CVT电控系统的结构，接口线路和软件设计。由于速比控制对综合控制策略影响很大，本文侧重分析了PID速比控制器，包括PID的控制原理、速比变化率PID控制算法和PID控制算法的一些改进。然后，在MATLAB环境下，对发动机实验数据进行处理，得到了该发动机的输出转矩、输出功率、燃油效耗率的数据模型，据此得到发动机的输出转矩MAP图等，进而获得最佳经济工作线和最佳动力工作线，并在Matlab/Simulink中建立了整车模型，以便对控制策略进行仿真分析及验证。最后，为了适应我国广大农村地区以及城乡结合地带的汽车行驶过程中经常会遇见道路摩擦阻力变化的情况，提出了在道路摩擦阻力变化时的综合控制策略，以解决驾驶员单纯选择经济性模式或动力性模式时，由于驾驶员的操作熟练程度和对路况判断准确程度不同和驾驶员个体差异会使动力传动系统控制效果不能实现最佳的弊端。并利用所建立的整车模型，对道路摩擦阻力变化时的典型工况进行了仿真分析。结果表明：经济性模式可以在小功率需求时表现出较好的经济性而在大功率需求时不能提供很好的动力性，动力性模式可以在大功率需求时提供较好的动力性而在小功率需求时不能有很好的经济性，只有综合控制策略能将经济性和动力性的优点很好地结合在一起，验证了本文提出的综合控制策略的可行性。更多还原

【Abstract】 In today’s society, the car has become an important part of life. People are nolonger just attached to the car ’s fuel economy and power, also put forward higherrequirements to automobile driving comfort, especially the car enters a family.Personal driver appeared in large numbers, the automatic car needs urgent. Becausemetal belt type continuously variable transmission (CVT: Continuously VariableTransmission) has the advantages of simple structure, convenient operation, hightransmission efficiency, energy saving and environmental protection and otheradvantages. It is an ideal transmission so it become the first choice for people. Inrecent years it has been the rapid development. This paper studies the selection ofmetal belt type CVT as the research object. And in view of the complex roadconditions, puts forward the comprehensive control strategy model to balance theeconomy and power demand.This paper first reviewed a large number of data. The metal belt type CVT’seconomy, power, transmission efficiency, reliability and life expectancy, emissionsand cost and other aspects of the advantages and the domestic and foreigndevelopment condition and future development trend are discussed.Secondly, the working principle of the metal belt type continuously variabletransmission is analyzed according to it’s structure. And give a detailed analysis ofmetal belt continuously variable transmission’s control technology for the modelingand simulation provides a good theoretical basis.Again, carry on the comparative analysis to the electro-hydraulic system that getthe effect of CVT control performances. And focuses on analysis of electric controlsystem including the structure of CVT electronic control system, interface circuit andsoftware design. As a result of ratio control get great influence on the integratedcontrol strategy. This paper focuses on the analysis of PID speed controller. Includingthe PID control principle, changing rate of speed ratio of PID control and PID controlalgorithms.Then, in the MATLAB environment take experimental data processing of engineand get the engine output torque, output power, fuel consumption rate of the datamodel, get the engine output torque MAP. Then get the best economic line and theoptimal power line and establish a vehicle model in the Matlab/Simulink. So that we can take the simulation analysis and verification of the control strategy.Finally, in order to adapt to the process of moving vehicle often meet roadfriction resistance changes in China’s vast rural areas and urban areas, we put forwardthe integrated control strategy when road friction resistance changes. In order to solvethe malpractice of the driver simply choose economy mode or dynamic mode and dueto the driver’s skill level and on the road accurate degree and the driver of theindividual differences can make power transmission system control effect can not beachieved best. And according to the established vehicle model, typical workingconditions of road friction resistance changes were simulated and analyzed. Theresults show that the economic model showed better economy in small power demandbut cannot provide good dynamic performance in big power demand. Dynamic modelcan provide better power in big power demand but cannot have good economy insmall power demand. Only the integrated control strategy can get the advantages ofthe fuel economy and power. So the result demonstrates the feasibility of integratedcontrol strategy.更多还原