ECAS客车车身高度的实时跟踪

Real-time Tracking of Ride Height for Bus with Electronically Controlled Air Suspension

为实现客车车身高度的精确跟踪,满足空气悬架控制要求,设计出一种基于电感式传感器的车身高度跟踪电路,传感器中的电感与跟踪电路由单片机共同控制,实现对传感器电感的充放电,单片机计算不同电感系数下的时间常数,间接获得实时的客车车身高度。并采用温度补偿电路和低温漂特性元件,适应客车工作环境温度的变化。设计出专用的滤波处理软件,既保证了车身动态高度的准确跟踪,又满足车身高度跟踪实时性的要求。试验表明,设计的车身高度跟踪系统启动后很快达到稳定且跟踪变化值在1 mm左右;当环境温度从30℃上升到80℃的过程中,跟踪高度的相对误差在1.9%左右,跟踪最大误差为5 mm,能够保证车身高度控制的准确性。

To exactly track the ride height of bus and satisfy the control demand of air suspension,a height tracking circuit based on the inductance sensor is designed.The inductance of sensor and the designed tracking circuit are jointly controlled by the single chip for the inductance charge-discharge,and the single chip calculates the time constant of different inductance to indirectly obtain the real-time bus height.Temperature compensation and components of low temperature-drift property are adopted to fit the ambient temperature change of the bus.Additionally,a special filtering software is developed to track the dynamic ride height exactly and simultaneously.According to the test results,the height tracking system comes to be stable soon,and the change of ride height is about 1 mm;the relative error is about 1.9% and the max value of tracking error is less than 5 mm when the ambient temperature rises from 30 ℃ to 80 ℃.So,the designed tracking circuit can ensure the veracity of ride height control.