Design And Realization Of Multi-bus Gateway For Integrated Bridge System

With the continuous improvement of the ship equipments’ automation level, there aremore and more kinds of the measurement and control equipments. Different equipments,under different environments, are installed with different kinds of field bus. While the realsituation is that these different field bus equipments often need to interact and share theinformation. Besides, the trend of the development in the future is to establish acomprehensive integrated bridge system as the information network platform for the wholeship, which, at the same time, needs all the equipment of the whole ship to be networked, inorder to realize the interworking between the upper layer management equipments and lowerlayer field bus. In this way, the ship’s drivers and decision makers could, through theintegrated bridge platform of the management layer, make the real-time monitoring andoperation for the lower layer field bus equipments. Therefore, it is impressive to solve theproblem, communicating the heterogeneous networks between management layer and fieldbus layer.This thesis firstly put forward an overall design plan for the multi-bus gatewaysystem, according to the needs and features of the integrated bridge system, in order to realizethe communication of the different bus equipments of the lower layer field bus of theintegrated bridge system. This plan takes the embedded real-time operating system as coresoftware, and PC104embedded platform as hardware carrier.According to reality, ships’ field equipments mostly use the CAN bus or RS422bus, andthe Ethernet is very popular in the upper management layer. Therefore, this thesis makes adetailed study on the technical features of the above three different communication interface,then, put forward a communicating scheme for the heterogeneous networks, which couldrealize the protocol transformation of several field bus and of the bus and Ethernet. This is thetheoretical basis for the communicating and information sharing between the field bus layerand upper management layer. Besides, this thesis, according the scheme, design a totally newcommunicating protocol, based on the integrated bridge subsystem, in order to prove thefeasibility of the scheme.This thesis puts emphasis on the design of the software of multi-bus gateway, andintroduces the functions and the technical points of the multi-bus gateway. According to thedesigned communicating protocol, this thesis makes a detailed discuss on the designs ofcommunicating interface of the CAN bus, RS422bus and Ethernet. According to the actual working situation of the integrated bridge system, this thesis designs the data receiving andsending for the three interfaces based on their respective features. Besides, according to theintegrated bridge system’s requirement for reliability, this thesis realize the redundancy designfor CNN bus and Ethernet.At last, this thesis completes the overall design of the application program for multi-busgateway, and, under the lab environments, simulates the environments of integrated bridgenavigation subsystem, building CAN network, RS422bus network and Ethernet, in order totest the function of the multi-bus gateway. The result of the test shows that the functions ofmulti-bus gateway has realized, since the communicating protocol of integrated bridgenavigation subsystem has be justified, and could make reliable protocol transformationthrough the multi-bus gateway.