Research of inverse mathematical model to high-speed trains

Operation safety and stability of the train mainly depend on the interaction between the wheel and rail. Knowledge of wheel/rail contact force is important for vehicle control systems that aim to enhance vehicle stability and passenger safety. Since wheel/rail contact forces of high-speed train are very difficult to measure directly, a new estimation process for wheel/rail contact forces was introduced in this work. Based on the state space equation, dynamic programming methods and the Bellman principle of optimality, the main theoretical derivation of the inversion mathematical model was given. The new method overcomes the weakness of large fluctuations which exist in current inverse techniques. High-speed vehicle was chosen as the research object, accelerations of axle box as input conditions, 10 degrees of freedom vertical vibration model and 17 degrees of freedom lateral vibration model were established, respectively. Under 250 km/h, the vertical and lateral wheel/rail forces were identified. From the time domain and frequency domain, the comparison of the results between inverse and SIMPACK models were given. The results show that the inverse mathematical model has high precision for inversing the wheel/rail contact forces of an operation high-speed vehicle.