Research On Magnetorheological Braking Technology And Current Controller Of Metro Vehicles

As an underground transportation method,the subway is of great significance to the development of urban transportation.As of the end of 2017,34 cities opened subway lines to ease the pressure on urban transportation.However,during the air braking process of metro vehicles,the violent friction between the brake shoe and the tread generates a large amount of harmful metal dust,which will lead to high concentration of metal particles in the stations and compartments where space is relatively closed,and unhealthy effect on passengers and subway staves.At present,the large-capacity ventilation device is installed to meet the air quality requirement in the underground space.As a new type of non-friction braking technology,magnetorheological braking does not generate harmful dust during braking,and solve the problem of metal particle pollution caused by traditional tread braking.It is a suitable braking technology for relatively enclosed space.The paper takes Chengdu Metro Line 1 as an example to study the application of magnetorheological braking technology in trailers.The research includes the magnetorheological brake device and the current controller of magnetic field.Firstly,according to the theoretical research of the magnetorheological braking technology of the subway and the installation requirements of the bogie,the mechanical structure of the single-disc braking device was designed,and the braking torque of the braking device was calculated.According to the theory of magnetic field,the magnetic circuit of the magnetorheological braking device was analyzed to determine the parameters of the excitation coil.Then the two-dimensional magnetic field analysis of the magnetorheological fluid braking device was performed using the ANSYS finite element analysis software to obtain the characteristic parameters of magneticrheological fluid in the magnetic field.In order to test the magnetorheological braking device,the current controller is designed according to the magnetic field parameters and the load characteristics of the excitation coil.The test results show that the current controller designed in this paper can meet the requirements of different constant current when the brake device is tested.After completed the manufacture and assembly of the magnetorheological braking device,we tested the braking device on the inertial test stand for no-load characteristics and static characteristics.According to the experimental data,the paper analyzed the effects of the magnetic saturation of the magnetic circuit,the magnetic properties of the material,and the gap width of the magnetorheological fluid on the braking performance.The results provide suggestions for further improvement.