Simulation On Anti-Slip Control Of Railway Vehicle Brake

Safety brake is an important issue for high-speed and heavy haul trains, for which sufficient braking power and wheel-rail adhesion are essential. Anti-slip control is designed to keep the adhesion in a high level, ensuring the effectiveness of the brake. Currently, braking force mainly comes from creep force of wheel/rail contact for most railway vehicles, i.e. the so called adhesion brake. Lots of studies have been done in wheel/rail adhesion, while it is still insufficient for the present engineering. Therefore, it’s very meaningful to study the influence of adhesion on railway braking.Main contents of this thesis are as follows:(1)A model of anti-slip braking system is developed, which includes a sub-model of railway vehicle dynamics, anti-slip control with logic gate, and calculation modules for brake torques of air and regenerative brake systems. Vehicle dynamic model is created with the multi-body dynamic software Simpack. Matlab/Simulink is employed to develop other parts of the model. Through this, railway vehicle dynamics and brake anti-slip control are considered in one simulation.(2)With the creep force model proposed by Polach, influence of important factors on braking performance is studied. This thesis focuses on three factors, which are static friction coefficient at zero slip velocity μ0, the reduction factor in adhesion Ka, and a reduction factor in slip Ks. Influence of curve radius on brake performance is also discussed.(3)Influence of air and regenerative brake properties on brake performance are investigated with model developed in this thesis.(4)Influence of creepage threshold, creep velocity threshold and car deceleration threshold in lagicgate anti-slip control are also studied.It is found that:(1) The friction coefficient has the biggest influence on brake performance of railway vehicle, while reduction factors in adhesion and in slip have little influence;(2) the curve radius has a great effect affection on brake time, but has a negligible influence on brake distance under the conditions invesgated in this thesis;(3) the brake torque increase during application of both both air and regenerative brake systems, but the causes are different. Anti-slip action may cause oscillation of the wheel linear velocity;(4) Acceleration threshold in logic gate control can neither be too large nor too small. A high acceleration threshold may lead to wheel slip even a wheel lock, while a low one reduces the usage of creep force. Creepage threshold and creep velocity threshold have little influence on brake performance.