| Raising speed of freight and passenger train and heavy haul of freight train is the maindeveloping direction of our railway transportation. The performance of braking system isfundamental to the safety of transportation. Raising speed and heavy haul are the challenges to thetrain braking system. In the essential, the brake system of train is the highest degree system ofguaranteeing safety. Under any serious condition and any train failure, the train braking systemmust make the train safely stop at the stopping distance that is decided by the railwaytransportation department. The derailment accidents and breaking couplers, many of whichhappened during braking, are not unusual since the speed of freight train is raised. Improving thebraking performance of freight train, especially of the long heavy haul freight train is more andmore important and urgent. This subject is also the state of the art in the world. At the same time,in the process of raising speed and marching into the high speed of passenger train, thedevelopment of braking system is still the one of the three key technologies. The most essentialtechnology, which is also under the research in the world, is to improve the performance of anti-skid system so that the optimal adhesion can be utilized to shorten the braking distance as far aspossible.The Electronically Controlled Pneumatic (ECP) braking system for long heavy haul freighttrain and the anti-skid system for passenger train are the topics of this thesis. The ECP brakingsystem for long heavy haul freight train is under the research in the North America. ECP is thesystematic project that includes the fields of communication, electronics, computer control andmachine. The research of ECP system design and the control portion of Car Control Device (CCD)are the heart of this thesis. The research route is to design the ECP system and build the model ofintelligent control of CCD, test ECP system and analyze one dimensional longitudinal dynamics oftrain and the safety parameters of train brake dynamics. As far as the anti-skid system isconcerned, it is the main sub-system of passenger train braking system. It concerns adhesiontheory between wheel and rail, data-acquisition, electronic control unit. This thesis is mainlyconcentrated with the heart of the anti-skid system that is the control system. The research processis followed with analyzing wheel-rail's adhesion during braking, designing the fuzzy neutralnetwork control system, testing control system and analyzing the performance under braking.The thesis can be divided into two separate paFts. The first is the research of the anti-skidcontrol system of passenger train. Firstly, the wheel-rail's adhesion during braking is researched,and the optirnal adhesion is proved to be existed at the inflexion point of speed. The inflexion isthe second differential of the speed curve and the meaning is the same to the jerk, so the jerk isintroduced into the control model of anti-skid system. The speed difference is replaced by the s1ipratio, because plenty tests show that the slip ratio is closely related to the adhesion. Secondly, ThefuZZy neutral netWork control model of anti-skid, which is realized using Visual C++ 5.0, is builtusing three parameters, namely the slip ratio, the acceleration and deceleration and the jerk.Finally, the indoor tests are used to analyze the performance of the control model, the result is thatthe anti-skid control model can indeed follow with the optimal adhesion of wheel and rail andmodulate the air pressure of the brake cylinder finely. This research work is most advanced and ispaving the way for the intelligent anti-skid system to be used in the high-speed train in the future.The second part is the research of ECP braking system of long heavy haul freight train. Atfirst, the braking system of freight train is devised and the test device is also built. The aimpressure of brake cylinder is calculated using br... |
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