Design And Implementation Of Real-Time Scheduling System For Shipborne Control Network

Due to the development of marine technology and military,the research of unmanned underwater vehicle is of great significance.Aiming at the real-time and deterministic problems of Ethernet in the communication of the ship-borne control system,this paper proposes a periodic time-triggered real-time communication scheduling scheme based on the master-slave mode.The scheme implements soft real-time communication scheduling of the shipboard control system at the application layer without changing the Ethernet network layer and the transport layer(such as UDP/IP)protocol.In order to ensure the real-time performance of the unmanned underwater vehicle(UUV)communication,this paper designs a master-slave parallel communication scheduling scheme based on the characteristics of the dual-switch network architecture of the target UUV.Under the premise of meeting the data exchange requirements of the shipboard control system,the scheduling scheme parallelly schedules two control units respectively connected to the two switches in the same time slot.It not only avoids the delay uncertainty caused by store-and-forward when a packet has a packet transmission conflict in the switch,but also effectively compresses the number of micro-scheduling cycles within a macro scheduling period,improving the real-time performance of the communication.The underwater master control unit which is responsible for the communication scheduling of the shipboard control system is designed and implemented.The master control unit uses the hardened industrial computer hardware and the VxWorks real-time operating system to improve the reliability and real-time performance.The modular and multi-tasking architecture is adopted to realize software on the underwater master control unit,and the above-mentioned communication scheduling scheme is used to realize the cyclic data exchange between the control units on the vehicle.In the overall design stage,the software function modules are divided,and the overall architecture of the software is given.In the detailed design and implementation stage,the design flow of the software modules and the function functions and interface functions involved are described in detail.A stand-alone test and system test platform for underwater master control software is built to test the functions of the software.The test results show that t communication scheduling scheme designed in this paper can meet the communication dispatching requirements the real-time demands.