Research And Application Of Marine Engine Redundancy Bus Data Communication Strategy

The marine engine has evolved from its original pure diesel engine to a cleaner and more eco-friendly natural gas engine and then to dual fuel engine with diesel and natural gas.The demand for engine control has also evolved from a single controller to a multi-control parallel control.To obtain more comprehensive engine status parameters,more monitoring nodes need to be added for data collection of engine operating conditions.Therefore the number of data that needs to be transmitted and shared in a marine engine data communication network is gradually increasing,and the original communication node cannot directly meet the existing communication requirement by directly accessing a control room with wires for reading and operating.Considering the particularity of marine engine working environment,it is a major trend to adopt CAN Bus with low cost,strong immunity,high transmission speed and high reliability as the main carrier of marine engine data communication network.CANopen protocol is chosen with multi-node capacity,high flexibility and easy node attribute configuration as the standard protocol of marine engine data communication network.The main research work of this paper is the implementation of CANopen protocol for marine engine data communication network.According to the actual demand,the reliability and reliability of communication network are increased by adopting redundancy and time window setting methods to improve the real-time performance of data transmission.Firstly the paper introduces the application of CAN Bus technology in marine engine data communication,analyzes the upper application protocol of CAN Bus machine and shows the necessity of adding redundancy in communication network.Taking dual fuel engine as communication model,the structure of marine engine communication network is analyzed,and the control parameters and monitoring parameters in the communication network are summarized.The CANopen communication network architecture with dual-fuel engine is built.Secondly,the core functions of constructing object dictionary,SDO communication,PDO communication,heartbeat communication and network management in CANopen protocol for marine engine data communication are implemented one by one.On this basis,in order to improve the overall reliability of the communication network,double CAN communication is successfully implemented in the bus communication by using dual CAN redundancy method.If the bus fault occurs,the bus can be switched to the bus without interruption.And solve the problem that the SDO flash write process in the CANopen protocol may cause a brush writing error.The use of the mutex lock function to improve the function may ensure that a configuration error occurs in the SDO configuration process.In the process data,in order to avoid the disadvantage that the lower priority nodes in the communication network cannot join the data communication,the real-time communication of each node is improved by adding the time window.Finally,the functional test of marine engine redundancy bus data communication is completed by CANtest host communication display and CANscope bus jammer.The test results show that the CANopen protocol constructed in this paper can fulfill the data transmission and sharing requirements of CAN bus application layer communication,after bus failure,do not disturb the bus switching,SDO configuration process error-free,set the time window to meet the real-time requirements of node communication.In summary,this paper builds a marine engine data communications network to meet the communication needs.The research work in this thesis provides technical support for marine engine control and condition monitoring.