【作者】 宋杰；

【导师】 苏楚奇；

【作者基本信息】 武汉理工大学 ， 车辆工程， 2011， 硕士

【摘要】 汽车电子稳定性控制系统(ESP)的工作性能和控制品质不仅与传感器和电子控制单元的控制逻辑有关,而且还与其液压系统的动态特性紧密相关。汽车ESP液压系统由多个液压元件组成,在电子控制单元ECU的控制下各液压元件协同工作,为实现对车辆运行状态的主动干预,根据车辆的不同行驶状态,对相应车轮施加液压制动力。汽车ESP液压系统作为执行机构,是一个在短时间内完成动态响应的高速响应系统。为保证ESP系统的工作可靠性和控制精度,而进行其液压系统动态特性研究是十分必要的。论文以某汽车ESP系统为研究对象,分析了其结构和工作原理。汽车ESP系统主要包括传感器、电控单元和执行机构三部分。电控单元对各传感器输送的车辆运行状态信号进行分析,若检测到此时车辆处于不稳定行驶状态或者有不稳定行驶的趋势,则电控单元对执行机构发出相应指令,执行机构采取动作,使车辆在其物理极限范围内稳定行驶。AMESim是世界著名的工程系统高级建模与仿真软件。利用AMESim软件建立制动助力器、制动主缸、预压单元、液压调节器、制动轮缸等汽车ESP液压系统关键元件的模型,仿真运行结果显示了各个模型的正确性；同时,根据流体力学相关理论,建立汽车ESP液压系统中主要模块(包括回液柱塞泵、低压弹簧蓄能器、节流器、二位二通电磁换向阀)的数学模型,为汽车ESP系统液压调节器的设计和动态特性的分析提供研究基础。利用AMESim软件,模拟汽车ESP液压系统被动制动、半主动制动和全主动制动三种工作状态下的增压、保压和减压工作过程,进一步验证了所建立的汽车ESP液压系统模型的正确性。根据动态设计理论,拟定汽车ESP液压系统动态特性评价指标,并以此对影响汽车ESP液压系统动态特性的关键因素如：液压介质、预压单元、回液柱塞泵、进液阀、排液阀、制动轮缸和低压蓄能器进行批处理仿真分析,得到相应的制动轮缸压力、流量等响应曲线。分析各仿真结果得出结论：液压介质、预压单元、回液柱塞泵、进液阀、排液阀、制动轮缸和低压蓄能器对汽车ESP液压系统动态特性有着重要的影响,在设计汽车ESP液压系统时,应将上述器件的特征关键参数进行合理匹配。更多还原

【Abstract】 Vehicle ESP hydraulic system is composed of several components, which operating performance and control quality not only related with sensor and the control logic of control unit, but also closely related with its hydraulic system’s dynamic characteristic. Hydraulic elements working collaboratively under the control of ECU, To realize initiative intervention to the running status of vehicles, exert the hydraulic pressure braking force to the corresponding wheel according to vehicles’ different transport condition. The hydraulic system is an electron stable procedure of vehicles, and it is an implementing agency that could completes the dynamic response with high-speed in a short time. In order to guarantee the ESP operational reliability and the control precision, it is essential to study hydraulic system dynamic characteristic.This paper takes the ESP as the study object, and has analyzed its structure and the principle of work. Vehicle ESP system mainly includes three parts which are the sensor, the electrically controlled unit and the implementing agency. Electronic control unit analyzed the vehicles running status signal which transported by sensors, if detected that vehicle in unstable operation or in unstable running trend, the electronic control unit will send corresponding instruction to the implementing agency, and then the implementing agency will action according the instruction, So that the vehicle can running stably within the physical limits.Used the AMESim software to establish the ESP model which include brake booster, brake master cylinder, pre-press unit, hydraulic control, brake wheel cylinders etc, and simulation results show the operation of each model is correct; Meanwhile, establish the mathematical model to main modules of ESP hydraulic system (which including the return to liquid piston pump, low pressure accumulator spring, throttle control, two two-way solenoid valve) according to the theory of fluid dynamics, which provides theoretical support to the hydraulic unit stability program design and dynamic analysis.Used the AMESim software to simulate vehicle braking passive electronic stability program, all semi-active braking and active brake booster under the three operating states, the process of packing and pressure of work, and this further validate the correct of the hydraulic automotive electronic stability program system model is.According to the dynamic design theory, development dynamic characteristics evaluation of vehicle ESP which called hydraulic systems. The dynamic characteristics of the hydraulic system include two aspects:a:the flow pulsation of Vehicle ESP hydraulic system, the instantaneous peak pressure and pressure fluctuations, which means System’s stability; b:response speed of the brake wheel cylinder pressure. And carry on the batch run simulation analysis to the Key factors (including pressure medium, precompression unit, returns to the fluid ram pump, to enter the fluid valve, platoon fluid valve, brake wheel cylinder and low pressure accumulator) which affect ESP hydraulic system dynamic characteristic, then get response curse of the pressure to responsed brake wheel cylinder and the flow of brake wheel cylinder. We get conclusion through analyzing various simulation results, which the precompression unit, returns to the fluid ram pump, to enter the fluid valve, the platoon fluid valve, the brake wheel cylinder and the low pressure accumulator has the important influence to the hydraulic system dynamic characteristic, and then it is request match reasonablely to the above components’ key parameter of characteristics when design the Vehicle ESP.更多还原