The Design Of MVB Muti-Protocol Communication Gateway

Now, with rapid development of domestic and international high-speed railways and high-speed trains, and distributed network control systems, train communication network (TCN) has been widely applied to the new trains in the world. In the five kinds of CRH Multiple Units (MU) developed in China, three kinds of MU use TCN network control technology. Multifunction Vehicle Bus (MVB) gateway is an important component of TCN, but its research and application in China are faced with long-term technology blockade and market monopoly of foreign manufacturers. And, because of the difference of the technical standards between the rail transmission equipment manufacturers, many board equipments do not support the MVB bus communication functions. This makes that MVB gateway is widely used. But many MVB gateways only have single protocol conversion function. This not only violates the openness principle of the train bus, but also affects the compatibility of MVB gateway.Under this research background and application environment, the subject refers to TCN network communication standards IEC61375-1, and combines Wi-Fi which is a current wireless communication hotspot, with CAN bus, RS-485 bus and RS-232 bus which are widely applied to trains. The paper proposes a MVB multi-protocol communication gateway scheme. Firstly, this paper outlines the overall development of TCN and MVB gateway, secondly we further research the key technology in the MVB multi-protocol communication gateway, especially the process data communication of MVB real-time protocol; Lastly, we analyze the design and implementation of both the multi-protocol gateway software and hardware in detail. For the hardware, the system uses a small embedded MVB communication board SSMV62AD and high-performance and low-power ARM processor STM32F103ZET6 developed by STMicroelectronics. And we design and debug PCB hardware board of MVB multi-protocol gateway. For the software, according to the principle of real time and reliability of MVB process data link layer communication, the paper proposes the train gateway residential port, the device gateway source port, and the periodically trigger access to occasional data sets schemes. And for the unreliable UDP transmission in Wi-Fi wireless communications, based on the TCP timeout and retransmission, sliding window, and go-back-n protocol response, we improve the efficient and reliable UDP packet transmission. We make a summary of data transmission characteristics of different buses, implement the mutual protocol conversion between MVB and four buses inμC-OSⅡreal-time operating systems, and design a real-time and scheduling multi-task application in the multi-protocol gateway.Finally, to detect basic data communications capabilities of the multi-protocol gateway, we build a CRH1 type MU fault simulation system in the LAB-8902 teaching experiment platform based on Intel Atom D510 processor and Linux operating system. The system can address the fault information occurring in the operation of CRH1 type MU. Besides, the paper analyzes the specific performance testing methods of MVB multi-protocol gateway in detail, and gives the relevant testing results and performance parameters analysis.