| In recent years,with the continuous expansion of the operation scale of high-speed EMUs,how to improve the adhesion ability of EMU wheels and rails has become an important topic in research.In the process of driving at high-speed,the condition of the wheel-rail surface will be very complicated,which may lead to wheelset coasting or even idling,and if the method cannot be taken to suppress it in time,it may cause serious accidents such as EMU derailment.Therefore,the research on the wheel-rail adhesion control of highspeed EMUs is particularly important.This paper focuses on the wheel-rail adhesion control method of high-speed EMU,first introduces the mechanism of wheel-rail creep-slip adhesion,and analyzes its adhesion-creepslip characteristic curve.By simulating the road conditions,the relationship between creep speed and adhesion coefficient under different rail surfaces was obtained.Several important adhesion calculation models are introduced and the factors affecting the adhesion of highspeed EMUs are briefly summarized.Secondly,A single-axis dynamic model of the train was established,and the simulation verification proved the feasibility of the model,and finally the idling simulation was added,which laid the foundation for the subsequent adhesion control research.Then,the traditional adhesion control method and the modern optimal adhesion control method were used to build the simulation module in MATLAB/Simulink,and simulate it.The traditional adhesion control method adopts the combined correction method,and the simulation comparison is carried out under the conditions of poor wheel-rail adhesion and poor wheel-rail adhesion.From the simulation results,it can be seen that the adhesive control system based on the combined correction method can increase output torque and reduce wheelset idling.However,when using this method,wheelset idling may have already occurred and the maximum adhesion between wheels and rails cannot be fully utilized.Due to the shortcomings of the combinatorial correction control method,the optimal adhesion control based on the variable step gradient method is proposed for simulation verification.By building a full-dimensional state observer,the pole configuration and the adhesion load torque are observed,and then the slope of the adhesion characteristic curve is obtained by using the least squares method with forgetting factor.A new research method-variable step gradient descent method is obtained by deforming the activation function,which can quickly search for the optimal reference creep speed,small fluctuation range,small overshoot,and effectively prevent wheel-to-wheel idling.Compared with the combined correction control method,the optimal adhesion control method based on the variable step gradient method can make full use of the adhesion between wheel and rail and give full play to the potential of the EMUS. |
