Disturbance observer based adhesion control for Shinkansen

When the wheels of the train slip on the rails, the torque is reduced to avoid the continuously slipping condition. This is because the coefficient between the wheels and the rails have a peak at a certain slip velocity. As the adhesive force changes at the rail condition, the wheels of the train suddenly slips. We propose to estimate the adhesive force by a disturbance observer. And the gradient of the adhesive force against the slip velocity is estimated by the proposal method. As a result, the motor torque is controlled such that the train is driven by the maximum adhesive force.