【作者】 孙琦；

【导师】 过学迅；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2009， 硕士

【摘要】 自动变速器可以减轻驾驶员的劳动强度,提高车辆乘坐的舒适性,是车辆传动系统发展的最终目标之一。无级变速器(Continuously Variable Transmission)具有性能优良、结构紧凑、操纵方便、成本低等优点,能够充分地发挥发动机的特性,提高汽车的燃油经济性、动力性、驾驶舒适性及行驶平顺性,是自动变速技术发展的前沿。本文首先对自动变速技术发展的现状进行了分析。结合现有试验条件,选择金属带式CVT为研究对象,简要介绍了金属带式CVT技术的现状和多项关键技术,控制系统是CVT关键技术之一。控制系统的核心是控制算法,智能控制是一门涉及领域十分广泛的新兴学科,也是控制理论发展的高级阶段,能够解决那些用传统方法难以解决的复杂系统的控制问题。本文研究将智能控制技术引入CVT的控制系统,寻求更佳的控制效果。分析了基于双压力回路控制系统的金属带式CVT的结构、工作原理和控制方式,着重研究金属带式CVT的速比和夹紧力控制。由于金属带的结构特殊,实现金属带式无级变速器的速比和夹紧力的精确控制十分困难,本文对金属带式CVT的传力特性和液压系统进行了分析和简化,基于台架实验结果,利用Matlab/Simulink软件建立装备金属带式CVT的整车仿真模型。设计并通过试验优化速比控制器及夹紧力控制器的模糊控制策略,与采用常规PID控制的控制器对比仿真试验;仿真结果表明,模糊控制是解决复杂系统控制问题的理想途径,经过优化的模糊控制策略应用于金属带式CVT具有较好的控制效果,模糊控制算法对于各种工况均具有较强的鲁棒性,且算法容易实现。最后,分析了模糊单片机的发展过程,结合实际条件,提出基于MC9S12DP256单片机设计金属带式CVT控制器软、硬件。设计了基于变频技术的CVT传动系统试验台台架和基于LabVIEW虚拟仪器的试验台控制系统,为进一步的研究金属带式CVT奠定了基础。更多还原

【Abstract】 Automatic transmission can reduce driver’s intense feeling and improve passenger’s comfortable feeling during a driving. It is one of the aims in the development of vehicle’s power train. A continuously variable transmission (CVT) is able to achieve more efficient operating levels with respect to drive performance and fuel consumption than conventional automatic transmission.The development of automatic transmission technology is analyzed in this paper. A metal-belt CVT is chose to be an object of study. The development of CVT and its core technologies is introduced, and the control system is one of the CVT core technologies. Control arithmetic is a key of control system. Intelligent control is a new type of control techniques, and it is an advanced control theory to solve complex control issues. Intelligent control is brought into control system of metal-belt CVT to seek a better effect of controlling.The configuration, elements and control ways of metal-belt CVT with dual-pressure circuit are analyzed. The ratio and line pressure control of metal-belt CVT are emphasized in the study. A simulation model of vehicle transmission system with CVT is built by Matlab/Simulink. Fuzzy logic control (FLC) strategy of ratio controller and line pressure controller are designed and optimized. Simulation of FLC compared with normal PID controller shows that optimized FLC strategies of ratio controller and line pressure controller have better effect on control of metal belt CVT.The development of fuzzy logic microcomputer is introduced. The hardware and software of metal-belt CVT ECU is designed based on MC9S12DP256. The test rig of CVT driveline which based on frequency conversion technology and the control system of test rig that based on LabVIEW are designed in the last, paving the way for further research.更多还原