Estimation of Lateral Wheel-Rail Contact Forces and Track Irregularities Through a Nonlinear Constrained Estimator

The running safety of railway vehicles depends on the real-time knowledge of wheel-rail contact interactions. The nonlinear nature of the latter, coupled with the random wear statuses of railway tracks, make difficult their direct measurement. Dedicated sensors are needed, but noise from wheel-rail contact harshness can corrupt measurements. A nonlinear state observer based on a Constrained Unscented Kalman Filter, which allows for constraining the estimated railway vehicle states and parameters, is proposed in the present work to estimate lateral wheel-rail contact forces and moments and identify lateral track irregularities. The developed technique can be applied for monitoring continuously the track conditions through in-service railway vehicles, enhancing control system effectiveness by estimating wheel-rail contact interactions based on measurements provided by onboard sensors.