【作者】 王伟玮；

【导师】 宋健；

【作者基本信息】 清华大学 ， 机械工程， 2011， 博士

【摘要】 汽车电子稳定性控制系统ESC的研究已是汽车动力学控制领域的研究热点和核心技术。ESC系统的主要功能分为三个部分：制动防抱系统ABS、牵引力控制系统TCS和主动横摆力矩控制AYC。ESC在汽车运动过程中，通过监测汽车行驶状态，根据车辆实际运动状态和驾驶员期望运动状态之间的差别，进行发动机扭矩调节或者通过主动制动的压力调节，保证汽车按照驾驶员的期望运动。ESC液压执行单元的关键性能就是主动增压，即主动制动功能的实现。本文针对主动增压的液压回路进行了研究，分析了动力源——柱塞泵的工作原理，提出了ESC液压执行单元无背压条件下实现主动增压功能的设计方法。在此基础之上，对主动增压相关回路的零部件进行了参数设计，减小了吸入阀小孔节流效应形成的压力降，在柱塞泵入口实现了0.4bar的真空度，从而实现了ESC液压执行单元的主动增压功能。为了研究ESC液压执行单元的动态特性，和ESC产业化以后的硬件参数匹配，本文建立了ESC液压执行单元的综合仿真平台，平台中考虑了增减压阀孔径的选择、柱塞泵排量的优化、蓄能器的容积设计，分析了这些参数对ESC系统主动增压速率和减压速率的影响，为ESC硬件匹配工作建立了理论分析基础。在ESC系统中，多采用电子控制单元控制的二位二通高速开关阀来实现制动压力的增压、保压、减压3种控制。传统高速开关阀的控制常采用脉冲宽度调制PWM（Pulse Width Modulation）控制，调制频率集中在10~100Hz这一低频范围内。本文提出了高速开关阀在高频PWM控制下实现比例开度功能的方法。建立了高速开关阀的数学模型，并搭建了高速开关阀PWM仿真模型，分析了2~4kHz频率下的动态响应特性，通过优化线圈匝数、弹簧刚度、阀座角度等参数，实现大范围的比例开度控制区间，利于ESC系统控制增压速度和实现限压功能。完成ESC液压执行单元的试制后，在ESC硬件在环仿真试验台和实车上进行了相关试验。结果表明，ESC液压执行单元能够实现主动增压的功能，通过改变增减压阀孔径、柱塞泵排量、电机转速等参数能够控制增减压的速率，并通过应用在限压阀上的高速开关阀的高频PWM控制，验证了比例开度功能以及各个参数对PWM占空比控制区间的影响因素。更多还原

【Abstract】 The research of vehicle electronic stability control system (ESC) is focus andcentral issue of vehicle dynamic control. The function of ESC includes anti-lockedbraking system (ABS), traction control system (TCS) and active yaw control (AYC). Inorder to make vehicle moves as driver’s wish, when the vehicle drives, ESC Monitorsvehicle driving status to adjust engine torque or brake pressure due to the differencebetween the actual state of motion of the vehicle and driver’s expect state of motion.The critical function of ESC hydraulic control unit (HCU) is that how to apply thebrake actively. This thesis studies the hydraulic circuit of the active brake system,analyzes the working principle of the power source-piston pump, and designs theparameters of relevant components in the hydraulic circuit of the active brake system.On the basis, the pressure drop as a result of the suction orifice effect has been reducedand a vacuum of0.5bar has been achieved in the inlet of the piston pump. After that,the function of active brake can be achieved.In order to study the dynamic of ESC-HCU and match hardware parameter afterESC manufacturing, This thesis establishes a simulation platform of ESC-HCU inwhich the choice of orifice diameter of inlet and outlet valve, the optimization of thepiston pump flow, the design of volume of accumulator are considered. Nevertheless,this thesis analyzes the influence of these parameters to the rate of pressure increasingand pressure decreasing which is the basis for ESC hardware match.In ESC, the two-status-two-way high-speed on/off valve is used to build up, holdor reduce the brake pressure. Traditional research of high-speed on/off valve in controlof pulse width modulation (PWM) concentrated in low frequency of10-100Hz. Thisthesis studies the proportion function of high-speed on/off valve in control of highfrequency of2~4kHz. This thesis establishes a high-speed on/off valve simulationmodel which is in control of PWM of2~4kHz modulation frequency inMATLAB-Simulink, and analyzes the proportion function of high-speed on/off valve indifferent duty cycle of the control of PWM. Nevertheless, a further study on influenceof different parameters to enlarge the control rage is discussed. By change the coilnumber, spring stiffness and seat angle, the ESC can control the rate of buildingpressure and limit the system pressure. After the sample of the designed ESC being manufactured, hardware in loop testand a test in actual vehicle are carried out. The result verifies the function of activebrake can be achieved and the rate of building pressure can be controlled by changingthe orifice diameter of inlet and outlet valve, piston pump flow and volume ofaccumulator. Nevertheless, the application of high-speed on/off valve in pressure-limitvalve in control of high frequency PWM verifies the proportion function of high-speedon/off valve and the influence of different parameters to the control rage.更多还原