Research On Synchronization And Switching Technology Of Redundant Dynamic Positioning System

Dynamic positioning system can make the vessel keep certain position and direction on the sea, have advantages that are not restricted by the depth of water and enter or retreat rapidly, and achieve the precise flexibility of ships. To many vessels which carry on the operation on the sea, it is necessary to use the dynamic positioning system. Because the reliability of the dynamic positioning system has a close relationship to the ship's safety, redundant dynamic positioning system is studied.to improve its reliability. The focus of this paper is to study the technology of synchronization and switching of redundant systemsFirst of all, a dual redundant dynamic positioning system is designed and built. The system reliability index and its calculation method are discussed. The reliability of the triple redundant system was calculated.Secondly, the technology of synchronization of redundant dynamic positioning system is studied. The general method of the synchronization in hardware and software is analyzed, based on which a software algorithm of synchronization which based on master-slave model is designed, and the software modules that synchronization algorithm needs is developed under the QNX OS.Thirdly, the switching technology of redundant dynamic positioning system is studied. As the prerequisite for switching, the type of system's faults and their detection methods are discussed To make the system switch reliably whenever faults occur, for hardware, circuits for arbitration and signal shifting used in redundant systems are designed. For software, the algorithm of data voting for triple redundant system.Last but not the least, the dual redundant system which has been built has been tested under the QNX OS. The hardware and software environment is introduced at first, including QNX OS and components of the dual redundant system which has been built. And then, the fault simulation project of dual redundant system is designed. In the end, the synchronization and switching performance of the system is tested, the response of system is analyzed and the test results are obtained.According to the test, the system can seize the power of control at the point of power on, run synchronize, detect the fault of the system, and the computers of the system can switch between master and slave. So, the paper has met the requirements and achieves the objectives of the design.