| In recent years,the development of China’s railway industry has advanced considerably.As the main artery of national economy,railway has effectively promoted the rapid development of economy.Based on the actual situation of our country,railway freight transport plays a dominant role in the transportation industry because of its advantages of heavy load,high speed,low cost.At the same time,it also puts forward higher requirements for its safety.However,it is very difficult to effectively realize real-time monitoring and transmission of the status information of freight trains due to the restrictions of no power generation device,frequent changes of compartment marshall,unattended train compartments and harsh working environment etc.So,The detection of freights status information has attracted much attention.This research subject is based on the project "The freight train power generation and real-time vehicle status monitoring system based on internet of things technology" in 2018,which is a major project of Liaoning institute of industry technology of colleges and universities.Firstly,by consulting a large number of technical literatures,the development of trains information detection and transmission technology at home and abroad was studied.Secondly,the main status information such as axle temperature,braking pressure and method for measuring relative temperature and humidity in compartments was demonstrated.Combined with the operation and characteristics of freight trains,a variety of wireless transmission technologies were compared,Zigbee wireless transmission technology was selected as the vehicle communication mode of this design,and the overall design scheme of the system was formulated.Then,the communication principle of Zigbee technology is described.And designed the communication method and protocol under the railway freight environment.Then select CC2530 chip as the core,and complete the hardware circuit design according to the overall design scheme of the system,including node hardware circuit,data acquisition circuit,power supply circuit,communication interface circuit and vehicle--ground communication circuit.Subsequently,the system software and the host computer are designed correspondingly through the IAR development environment and the Z-stack protocol stack.Finally,this thesis is based on TI company’s data packet detection software between Packet Sniffer,program development environment IAR and hardware Zigbee USB Dongle circuit board.A test platform for packet transmission status of wireless network between detection nodes is verified.The network construction and data transmission performance test of different distance compartment nodes are simulated,and the transmission effect under different conditions is verified.The transmission of vehicle--ground information is simulated by GPRS communication module,and the simulated freight train status information collected is displayed in the man-machine interface,which basically verifies the feasibility of the research design.The work of this thesis has certain referential value to solve the problem of freight train information monitoring in the future. |
