Research Of The Bus Communication Technology For Unmanned Underwater Vehicle Propulsion System

In recent years,Unmanned Underwater Vehicle has gradually become a research hotspot in the field of ocean development and military monitor with its advantages of compact size,easy controllability,long time of endurance and strong carrying ability.Fieldbus technology has become one of the developing trends in the field of automation because of its open communication protocol,intelligent field devices and decentralized system structure.This paper considers the Unmanned Underwater Vehicle as application object,and applys the fieldbus technology to the communication network on the vehicle's propulsion system.Firstly,according to the working condition of the Unmanned Underwater Vehicle and characteristic of propeller distribution,three communication protocols respectively named Modbus,CAN bus and industry ethernet are selected to construct the communication network for the propulsion system.This paper then introduces these protocols in detail,and analyzes their communication principle,data frame forma,ayered structure and so on.It provides theoretical basis for realizing the protocols based on software and hardware.Next,this paper proposes a designing scheme for the communication network of propulsion system of the Unmanned Underwater Vehicle,and designs the hardware circuit for the control board of the variable frequency unit.The control board can collect signal,control the drive circuit,and communicate with Modbus,CAN bus or industry ethernet protocol.After that,this paper develops the protocols on the hardware basis.In addition,in order to resolve Modbus protel's problem such as poor performance in communication efficiency and fixed priority of slave stations,this paper proposes an improvement project based on a weight-variable token-ring model.After analyzing the project in theory,this paper makes a simulation experiment in the Matlab environment.The result shows the improvement project can improve the communication efficiency,and help the slave station with low priority avoid packet loss.Finally,in order to complete the communication system,this paper designs a control panel for local control and a upper computer program for remote control.What's more,a experiment is designed to test the feasibility of the Modbus protocol.The test results show that the communication network designed in this paper can transfer data reliably,and can be applied to propulsion system of the Unmanned Underwater Vehicle for information exchanges.