Research On The Train Communication Network Based On The Industrial Ethernet Technology

ABSTRACT:Traditional Ethernet Technology has the characteristic of non real-time and non-deterministic, so it can not be directly applied to train communication network. After making an in-depth research on several unfavorable factors, an effective method is got by changing the Ethernet communication and scheduling mechanism. Also, an experimental platform is designed for testing it.Based on the star network, the real-time characteristics is analyzed about the shared Ethernet and switched Ethernet,the result shows that switched Ethernet meets requirements of the train communication network. The Time-Triggered Architecture is introduced to the Ethernet; because it's Time-Division Multiplexing Access (TDMA) mechanism can ensure Ethernet's real-time and deterministic communication. Based on the time-triggered architecture, this paper gets a new deterministic scheduling mechanism. Through analyzing, a macr-scheduling cycle of train communication network is calculated.For establishing time-triggered Ethernet network, according to the IEEE1588 precision time synchronization protocol, this paper propose a new method for slave clock 'time compensation. The problem of dramatic change about time is solved. The process of simulation modeling and analysis by MATLAB proved that the new method is scientific and reasonable.In order to establish the communication network for experiment, two kinds of communication node is designed based the Ethernet Technology. Also, the real-time operation systemμCOS-Ⅱand TCP/IP protocol stack is transplanted to the communication node. Then the communication network based switched Ethernet is established. Based on the experimental platform and IEEE1588, precision time synchronization protocol is designed, in the other word, a precision clock synchronization network is realized.Last, In order to get the network'real-time response capability and clock synchronization accuracy, this paper designed an accurate measurement method, qualitative analysis is made about the experimental platform.