Research On Speed Control Technology Of Unmanned Electric Locomotive For Restraining Wheel Rail Slip

Nowadays,coal still plays the role of "ballast stone" in ensuring our energy security,and realizing intelligent coal mining is of great significance in promoting our energy supply revolution.As the key equipment of auxiliary transportation in coal mine,it is of great significance to study the driverless control technology of mine electric locomotive to reduce the number of underground workers and reduce the safety risk.The driverless electric locomotive runs in the complex and changeable roadway environment,and its wheel-rail contact environment also changes in real time.Once the electric locomotive skidding occurs during traction or braking,it will cause the risk of wheel rail rubbing and electric locomotive losing control,which seriously affects the safety of coal mine production.It is of great significance to design an anti-skid controller suitable for unmanned electric locomotive to ensure the safety of intelligent and unmanned mine auxiliary transportation.The main contents of the thesis are as follows:Firstly,the theory of wheel-rail rolling contact and adhesion is introduced,and the creep phenomenon caused by relative sliding in wheel-rail rolling contact area is analyzed.The relationship between adhesion coefficient and creep rate is revealed,and the factors affecting wheel-rail adhesion are analyzed,which provides a basis for the following control strategy research.Secondly,Aiming at the problem of wheel/rail slip during the speed increase of electric locomotive,a anti-skid control method based on the balance point correction of creep rate is designed.Considering the complex and changeable environment of underground roadway,the adhesion state of rail surface also changes,a kind of adhesion coefficient observer and the optimal creep rate observer are designed to realize the realtime estimation of the adhesion coefficient and the optimal creep rate of rail surface.In addition,in order to eliminate the noise generated by sensors in practice,an adaptive least square slope estimation method is designed to make the real-time estimation results of adhesion coefficient and optimal creep rate smooth and stable.The anti-skid control method can maximize the use of track adhesion and effectively restrain wheelrail skid.Then,a vector control method based on load torque feedforward was designed on the basis of double closed-loop vector control of traditional permanent magnet synchronous motor,aiming at the possible skid phenomenon of electric locomotive in constant speed cruise mode.Aiming at the shortcoming of slow dynamic response of traditional Romberg torque observer system,an improved torque observer is designed to realize fast recognition of load torque.This control method can effectively restrain the rapid increase of speed when the track viscosity changes,and has the effect of inhibiting wheel-rail slippage.Meanwhile,it improves the anti-load disturbance performance of permanent magnet synchronous motor.Finally,on the MATLAB/Simulink simulation software and the experimental platform,the two anti-skid control methods designed in this thesis are verified by simulation and experiment.The results show that the anti-skid control method based on the balance point correction of creep rate can effectively restrain the skid phenomenon caused by the abrupt change of rail surface during the starting process of electric locomotive.The vector control method based on load torque feedforward can effectively restrain wheel-rail slippage and improve the anti-load disturbance performance of permanent magnet synchronous motor in the constant speed running stage of electric locomotive.