Wheelset Dynamics and Wheel Slip Detection

摘要

This paper proposes a radically new approach for the detection of wheel slip/slide, which may provide an important alternative and advantageous technique in traction/braking control systems to maximise the use of adhesion in poor contact conditions. Instead of the direct measurement of speed difference between wheels and the train, the proposed concept explores the variations in wheelset dynamic properties caused by condition changes at the wheel-rail contact and therefore detects slip conditions from the dynamic behaviour of a wheelset indirectly. In this study, the configuration of a typical traction system is used, consisting of an induction traction motor (with associated power inverter and field-orientated control) connected to a wheelset via a gearbox, but the developed technique may be also applied to braking control systems. Non-linear wheel-rail contact laws are used in the simulations, and linearised models at different contact conditions are developed to enable a detailed analysis of the key dynamic properties. Simulation results are produced to support the proposed idea. The main aim of the study is to present the basic principle and theoretical background of the novel concept, although some of the fundamental issues for practical implementations are also discussed.