Slip Ratio Control in Rail Vehicle Braking with Sliding Mode Control Method

Wheel slide protection is the safe-related fundamental function for rail vehicle braking systems. The braking distance depends on the adhesion condition and the anti-skid controller's performance. In this paper, a sliding mode slip ratio control method was proposed based on online estimation of the tangential force between wheel and rail. Simulation results show that the estimator can estimate the tangential force with braking force and wheel's angular speed as inputs. And the actual slip ratio can track the reference value whether it is a constant or time-variant one. This method helps to control the sliding degree when wheelsets skidding during braking under degraded adhesion condition.