A Terminal Sliding Mode Algorithm for Train Velocity Tracking Considering Wheel-Rail Adhesion

Automated train operation plays more and more critical role in railway development. One of the core problems is to achieve that train velocity tracks the desired speed as soon as possible. Traditional velocity tracking algorithm is only based on the train body dynamic model while ignore the effect of wheel-rail adhesion on the train control. In practice, we can only control the driving torque on wheels, and further control the train speed indirectly. The complex nonlinear wheel-rail adhesion and uncertainties bring us big challenges to design the controller. In this paper, the wheel-rail adhesion model is firstly combined with train dynamic model, and a terminal sliding mode algorithm is used to deal with the nonlinear control problem. The control scheme realizes that the velocity error converges to zero in finite time. Numerical simulation results are succeeded to verify the efficiency of the presented controller. Furthermore, a comparison between different algorithms shows that the proposed method performs better in rapid convergence than other methods.