Development of an Extended Kalman Filter for Determination of the Normal Wheel-Rail Contact Force

The estimation of railway friction level requires an accurate determination of the wheel-rail contact force.This study developed an extended Kalman filter to estimate the normal wheel-rail contact force.The filter is based on a dynamic system, taking both the axlebox acceleration and vertical primary suspension force as the main input variables.The multi-body dynamics simulation results, including the simulated axlebox acceleration, primary suspension force and wheel-rail contact force, were then used to tune and validate the extended Kalman filter.The study indicates the extended Kalman filter, is reliable for estimating the normal wheel-rail contact force.To determine the sensitivity of the filter, the effect of the vehicle speed was examined.The study shows the accuracy of the extended Kalman filter may decrease with the increase in the running speed of the vehicle.By tuning the filter based on a high running speed, the proposed extended Kalman filter is promising for the determination of the normal wheel-rail contact force in practice.