Research On Train Axle Temperature Detection System Based On MVB Bus

The development of train technology has become the focus of China's industrialization process,and the safety,reliability and cost of trains are in urgent need of reaching higher standards.When the train is running,the bearings in the axle box of the bogie will generate a lot of heat under the bad working condition,which will shorten the bearing's life and even cause an accident.Therefore,it is very significant in ensuring driving safety by installing axis temperature detection system on the train to detect axis temperature in time and prevent safety hazards.Based on the development and trend of train axle temperature detection,this paper presents a train axle temperature detection system which is suitable for Train Communication Network(TCN).TCN network includes wire train bus(WTB)and multifunction vehicle bus(MVB).MVB is applied as vehicle internal control bus to provide excellent speed of response.Axle temperature detection devices are installed on the front and rear bogies of each carriage.The device detects the axle temperature by means of contacting measurement and can be directly connected to MVB bus.In each MVB network segment,there is a bus manager,which is responsible for polling the axle temperature detection devices.At the same time,the data is sent to the gateway for converting the protocol.Then the data is sent to the driver's cab through WTB bus.The axle temperature data and alarm status are displayed on the LCD screen.The axle temperature detection device is the key part of the whole system.Through the analysis of the requirement of the train axle temperature detection,a new type of axle temperature detection device is proposed in this paper.This device can obtain temperature data efficiently and judge alarm conditions.It has MVB1 equipment function and can be used as MVB slave equipment to connect to train bus directly.It has the characteristics of simple structure,fast response speed and low cost.The digital temperature sensor QT18B20 is selected as the axle temperature measuring element,and each of the four axle boxes of the bogie is fixed a sensor to detect the axle temperature indirectly.Then the hardware,mechanical and electrical interface design are carried out,and a new type of redundant circuit design is given.Axis temperature detection controller is the core of axle temperature detection device.In order to simplify the system structure,a controller based on single-chip FPGA is designed.The top-level design of the system is divided into four modules: sending module,receiving module,axis temperature processing module and logic control module.In Quartus II development environment,Verilog HDL hardware description language is used to complete the code implementation of each module.Then,the functional simulation tests of each module are carried out using ModelSim simulation platform and the simulation waveforms of each module are given.Then,the online logic analyzer Signal Tap II is utilized to collect real-time signals from the chips and complete board-level simulation.Finally,an experimental platform is built to test the functions of the axle temperature detection device,including MVB communication test,temperature measurement test and alarm condition judgment test.The results show that the device can achieve the desired results.