Research On Scheduling Algorithm Of TTE

With the rapid development of aviation technology as well as the increasing demand for electronic equipment performance,the architecture of avionics system is moving toward modularization,integration and standardization.The improvement of airborne network communication technologies has been greatly facilitated by the complexity of electronic systems and the amount of interactive information.Not only the physical structure of the system and the means of information interaction,but also the system development,verification process,system complexity,scalability and internal operability are determined by the network design.For the high-security electronic control system of distributed airborne architecture,the real-time and deterministic communication between network nodes is the key to the realization of the system.The interactive upgrade of airborne information enables traditional full-duplex switched Ethernet to expose its shortcomings,such as large delay jitter,low synchronization accuracy and insufficient time certainty,which are the main problems for the next generation of aeronautical communication networks.Therefore,time-triggered Ethernet(TTEthernet or Time-Triggered Ethernet or TTE)which is a time-deterministic network technology has important application requirements in the aerospace areas,automotive industry and other fields.Based on the analysis of TTE network application scenarios,technical requirements and design ideas,this paper focuses on the time scheduling mechanism of TTE networks.First of all,the key technical mechanism of time-triggered Ethernet is introduced,including its architecture,network topology,time synchronization mechanism,fault tolerance mechanism and time scheduling mechanism.Secondly,two classic schedules are introduced and the design principles of them are also summarized,so this paper indicates the disadvantages of existing scheduling methods and proposes the optimization and improvement direction.Then,based on the pre-processing results of load balancing,taking the scheduling time of the nodes as the optimization variable and establishing optimization problems by minimizing the response delay of each TT task,a new kind of scheduling algorithm based on load balancing for the time-triggered service is proposed which mainly adopts the staged scheduling strategy,and its design idea as well as implementation process is elaborated.Furthermore,in order to verify the effectiveness of the scheduling algorithm,a scheduling table generation software with visual operation interface is designed.The function structure of the software is divided into two parts,one part named front-end application is responsible for the visual operation interface and displaying the scheduling results,and the other part named back-end system is in charge of executing the LBRDM algorithm and the Gurobi solver.Finally,the LBRDM scheduling method is verified and analyzed according to the scheduling results of the software.The results show that the proposed method for generating the time-triggered service scheduling table is effective and applicable to single-hop and multi-hop network topologies,which can guarantee the response delay of real-time services,the available bandwidth resources of non-real-time services as well as the flexibility of scheduling.Therefore,the scheduling method proposed in this paper can better meet the performance index of TTE.Therefore,this paper provides a meaningful reference for the research of schedule generation method of time-triggered tasks.