集成式电液制动系统建模与压力控制方法研究

Modeling and Pressure Control of Integrated Electro-Hydraulic Brake System

以集成式电液制动系统(integrated electro-hydraulic brake,I-EHB)为研究对象,建立了其机械、液压子系统的数学模型,得到了系统的5阶非线性状态方程.在I-EHB系统处于不同压力下的平衡状态的方程进行线性化处理,得到系统的传递函数,并利用AMESim软件验证了传递函数的正确性.设计了基于PID控制的位置-压力串级控制器,伺服主缸活塞处于死区行程内,采取以补偿孔位置为活塞运动目标的位置反馈控制;超过死区行程后,采用以伺服主缸目标压力跟随为控制目标的压力反馈控制.将伺服主缸压力响应时间和超调量分别控制在80 ms,6%内,有效提高I-EHB系统的制动安全性和舒适性.

A fifth-order model for I-EHB (integrated electro-hydraulic brake) system was derived from its mechanical and hydraulic subsystems. The model was linearized at equilibrium states, and then the transfer functions of the I-EHB system were obtained and verified by AMESim software. A cascade controller composed with position and pressure control was designed based on PID control. The control process was arranged that, while the position of the piston was in the deadzone of servo master cylinder, the piston was controlled to move to cover the pressure compensated orifice with position feedback, once the piston was beyond the deadzone, the cascaded controller could be switched into pressure control. Results with the cascade controller show that, the response time of the pressure in the servo master cylinder is less than 80 ms and the overshoot is within 6%, which helps improving the braking safety and comfort.