Analysis of the Locomotive Wheel Slip Controller Operation During Low Velocity

Abstract

Locomotives are equipped with slip controllers that improve their adhesion utilization and keep wheels slip velocities at appropriate values. The current slip controllers typically correctly work during the regular train run. However, there are some cases when some slip controllers may fail. The correct operation at low velocities is one of the cases in which the slip controller can fail. The long-time response of the velocity measurement that is caused by incremental encoders with a low number of pulses per revolution is causing the problem in this case. The wheel slippage can occur when the adhesion conditions are adverse, and applied forces are high in this case. This paper describes a novel slip controller based on the unscented Kalman filter that correctly works during the train low velocity operation with any adhesion conditions. The slip controller was designed with taking into account all aspects that influence the controller operation. Therefore, the adhesion, electric drive, the slip controller, and problem background are described in the paper. The slip controller functionality is verified on measured data and a mathematical model that was verified on the measured data.