Research And Simulation Of Metro Braking System

Accompanied with the accelerating process of the urbanization, urban transport is under increasing pressure. In order to form a convenient urban transport network, more and more cities put subway into their construction plans. Metro as the main force of the urban rail transit, its technical performance can directly affect the city’s carrying capacity. Especially braking technology, as one of the key technologies to guarantee the train’s safe running, has received considerable concern.This article adopts the numerical simulation technique to research the braking system on our county’s Metro vehicles. Combined with the features of the Metro braking system at home and abroad, this paper analyzes the structure, the control mode and the braking functions of the braking system and so on. The pneumatic control unit and the electric control unit form the chief components of domestic Metro braking control system which takes computer-controlled electrical direct electro-pneumatic braking system.In the pneumatic control part, the EP valve, the relay valve, the empty-load valve and the emergency valve are analyzed of the physical structures and working principles. Then, their performance curves are obtained through building the pneumatic control models in the AMESim software. Finally the model of the car direct-braking unit will be built.In the electrical control part, the classification and the characteristics of the brake control policy are introduced. According to the Metro vehicle brake control policy, this paper researches the system’s power calculation and the way of the system power distribution. Then the components of the models are established in the AMESim software, which mainly consists of vehicle control unit (VCU), brake control unit (BCU) and traction control unit (TCU) of traction control part and so on. On the basis of the previous work, the Metro control network of the braking system will be set up.Then, the real-time simulation model of the whole train (4M+2T) brake system is established in the AMESim software according to the actual situation during the brake process. After that, the performance curves are obtained through running the models in service brake, emergency brake and fast brake conditions, mainly containing the pressure rose curves in brake cylinder, the braking distance curves, the braking acceleration curves and the system power distribution curves, at the end, this part analyzes the braking performance.Finally, according to the performance curves, the optimization scheme of braking system which is for advising purposes is obtained through analyzing the performance impacts of various relevant parameters in braking system.