Anti‐slip control based on optimal slip ratio for heavy‐haul locomotives

To solve the problem of wheelset slip and effectively exert locomotive traction, a protection method of anti‐slip control with integral sliding mode based on optimal slip ratio is proposed. First, a dynamic model of heavy‐haul locomotives is established and a sliding mode observer is designed to observe the real‐time adhesion coefficients of heavy‐haul locomotives. An extremum seeking algorithm with sliding mode is used to monitor and search the optimal region of slip ratio. Then, a PID compound control is combined to weaken oscillations in the sliding mode extremum seeking. Finally, an integral sliding mode controller with new reaching law is designed to ensure the slip ratio of locomotives running on different rail surfaces are at optimal values, which maximise the utilisation of adhesion between wheels and rails. Simulation results also verify the feasibility and effectiveness of the integral sliding mode variable structure control method based on optimal slip ratio in the anti‐slip traction system of vehicles.