A novel estimator for adhesion force of railway vehicles braking systems and reference speed calculation

In this paper, sliding mode control is designed as the controller for railway vehicle braking systems and a novel estimator is introduced to estimate the immeasurable adhesion force torque, which is based on the locomotive wheel model and a proportional integral control. Then value of adhesion force can be achieved by a simple division transformation of the estimated adhesion force torque. The value of adhesion force calculated from the estimation of adhesion force torque has three benefits. Due to the accuracy of estimated adhesion force, it can be used to calculate the reference speed and used as a necessary parameter of controller. What's more, it can be used as an input of the algorithm for calculating the optimal slip rate, which lays the foundation for future research. The simulation verifies the performance of the proposed estimator.