| Railway transportation has the characteristics of wide space,long time,high complexity and strong dynamic.How to dynamically adjust the speed of trains in different space positions according to the needs of road network control(that is,temporary speed revision)is the key to ensure the safe and orderly operation of the entire railway transport network.This dissertation aims at the demand of train speed dynamic control in railway network.Combined with the existing method of vehicle identification using RFID in railway system,a set of Internet of things system with temporary speed revision of railway network is put forward.Key issues involved in the system,such as robustness of RFID communication,tag energy consumption and energy acquisition,vehicle positioning are studied and some effective methods are put forward.First,according to the demand of speed limit in dynamic section of train network,In this paper,a train temporary speed revision control system based on RFID wireless identification and gridding real-time information transmission is proposed.Train temporary speed revision control system is implemented by laying RFID tag in the center of the track.The on-board RFID reader can automatically read the data on the electronic tag while the train is on the train and interact with the control system on the vehicle or alert the driver to the driver through screen display and sound so as to realize the speed limit in the area.Second,aiming at the problem that the transmission quality of RFID signal is easily affected by the deployment environment,the design technology of RFID tag antenna with high robustness and environmental influence is studied.A highly robust tag antenna is proposed.By designing the antenna structure and dimensions,when the RFID tag is attached to the dielectric material surface and the conductor surface,the tag antenna can work in two independent modes.It is dipole mode and patch antenna mode(equivalent to slot array mode)respectively,so that the tag can maintain a consistent gain both on the dielectric surface and on the conductor surface.It overcomes the problem that the universal label attached to the conductor surface in the current market can not work.Third,aiming at the problem of energy consumption of RFID tag on train track,the energy acquisition method of RFID tag environment is studied,and a RFID active tag structure with solar energy charging is proposed.The energy consumption and charging efficiency of the tag in the communication process of the temporary speed revision system of the train network are studied and analyzed in depth.The simulation results show that the the solar RFID tag designed by the authors allows the tag to always maintain sufficient energy for communication and data transmission.Fourth,aiming at the problem of how to ensure the train to pass safely at reasonable speed in the multi-layer speed limit interval,a train positioning method based on "extreme learning machine" is designed in this paper,which improves the positioning accuracy of the train on the track line.Then,based on the idea of event and state of dynamic model,according to the principle of "event trigger,state transition",a method of information processing of multi-layer temporary speed revision interval is proposed,which overcomes the confusion of judgment in multi-layer interval judgment.In order to control confusion and provide drivers with accurate information and warning of speed limit,the train can drive safely and pass through the speed limit interval at a better speed at the same time.Finally,the research and design of the train speed limit control system are completed,the experimental tag module and the reader module are designed and developed,and the experimental system is built.The above research contents are tested and verified in the real application environment.The experiment shows that the relevant technical methods and measures proposed in this paper are effective.To some extent,it can solve the problems existing in the train temporary speed revision project. |
PDF Full Text Request