城轨列车减速度反馈制动力闭环控制方法

针对城轨列车在目前理论减速度开环控制模式下,实际制动减速度精度较低的问题,提出一种基于参数估计的制动力闭环控制方法。将列车运行于坡道、弯道等路段产生的附加运行阻力和摩擦副摩擦系数变化等导致的实际制动力偏差等效为列车在制动过程中所受的总扰动,以列车减速度和制动缸压力等作为输入,通过梯度估计方式对该扰动进行求解。根据总扰动的估计值对列车制动力控制目标进行在线修正以实现城轨列车制动力闭环控制。为便于在实际的制动系统电子制动控制单元中进行编程,将上述控制算法进行了离散化。仿真和硬件在环试验结果表明:参数估计算法能够对恒定扰动和变扰动进行估计,估计值的收敛速度与估计器系数呈正相关,但当估计器系数大于1之后,收敛速度趋于饱和。制动力闭环控制算法能够提高列车实际减速度对其目标值的跟随性,当坡道坡度呈正弦变化且实际摩擦系数同时随速度变化时,闭环控制的减速度偏差由开环时的0.36 m/s~2降至0.08 m/s~2。并且当制动过程中发生滑行时,防滑控制与制动力闭环控制仍能较好兼容,滑行轴速度、制动缸压力及列车实际减速度的变化满足预期。

Deceleration-feedback braking force closed-loop control method for urban rail train

Aiming at the problem that the accuracy of the actual braking deceleration of the urban rail train is low under current theoretical deceleration open-loop control mode, a closed-loop braking control method is proposed based on parameter estimation. The actual braking force deviations caused by the additional running resistance when the train is running on ramps and curves and the change of friction coefficient of friction pair are taken as an equivalent total disturbance suffered by the train during braking. Then, taking the train deceleration and braking cylinder pressure as the inputs, the gradient estimation approach is adopted to solve the total disturbance. According to the estimated value of the total disturbance, the control target of train braking force is modified online to realize the closedloop control of the urban rail train braking force. In order to facilitate the programming in the actual electronic braking control unit of the braking system, the above control algorithm is discretized. The simulation and hardware-in-the-loop test results show that the parameter estimation algorithm can estimate both constant disturbance and variable disturbance, and the convergence rate of the estimated value is positively correlated with the estimator coefficient. However, when the coefficient increases to greater than 1, the convergence rate tends to saturation. This braking force closed-loop control algorithm can improve the tracking performance of the actual train deceleration to the target value. When the slope of the ramp changes according to sinusoidal law and at the same time the actual friction coefficient changes with the velocity, the deceleration deviation of the closed-loop control decreases from 0. 36 m/ s 2 to 0. 08 m/ s 2 . Moreover, when sliding occurs during braking, anti-skid control and braking force closed-loop control still can be compatible well, and the changes of the sliding axle speed, brake cylinder pressure and actual train deceleration meet the expectations.