Research On Modeling And Optimal Scheduling Technology For Time-Triggered Ethernet

Safety-critical electronic systems impose strict requirements on the real-time performance,stability and bandwidth of communication networks.As the "nerve" and "skeleton" of safety-critical electronic systems,communication bus faces difficult problems such as poor real-time performance,uncertain transmission delay and jitter,poor fault tolerance and low bandwidth.Time-triggered Ethernet adds a Timetriggered mechanism on the basis of IEEE 802.3,fully adapting to the typical business requirements of real-time,reliability and stability in aerospace,industrial control and other fields.With the rapid increase of network scale and the increasing data traffic,how to improve the scheduling performance of Time-triggered Ethernet and enhance the quality of service of Time-triggered Ethernet transmission has become the research focus and of Time-triggered Ethernet technology.This paper focuses on the Time-triggered Ethernet modeling and optimization scheduling technology.The specific contents are as follows:(1)A Time-triggered Ethernet optimal scheduling model is established.The working principle of Time-triggered Ethernet communication is discussed from the Time-triggered Ethernet topology,frame structure and message structure.The clock synchronization technology that guarantees the time trigger mechanism is deeply studied.Two scheduling mechanisms based on Time-triggered and event-triggered are analyzed.According to the network topology,message type,and transmission constraint,the Time-triggered Ethernet is modeled.(2)A Time-triggered Ethernet scheduling technology based on genetic annealing algorithm is proposed.The genetic algorithm and simulated annealing algorithm are theoretically researched from three aspects: definition,characteristic and process.The Time-triggered message transmission constraint is innovatively combined with the Time-triggered Ethernet objective function in the form of a penalty function,and an adaptive function with configurable parameters is designed.Besides,the coding,selection and crossover processes are optimized,and the idea of annealing is used to design the individual mutation process.An extensible experimental platform is built on the complex star topology,and a large number of performance tests of the scheduling algorithm are carried out.The experimental results show that: compared with the standard genetic algorithm,the hybrid scheduling algorithm improves the Time-triggered message schedule solution speed by 15.73% and reduces the end-toend delay of Time-triggered traffic by 6.82%.(3)A Time-triggered Ethernet optimization scheduling technology based on fast increment is proposed.Based on the idea of constraint programming,by setting the basic scheduling unit,the Time-triggered Ethernet scheduling problem is transformed into a mixed integer programming problem.Through the rapid increment of the basic scheduling unit,the multi-hop delay is corrected backtracking,and the optimization time triggers the solution process of the message static scheduling table.Based on the OMNe T++ simulation tool,a Time-triggered Ethernet scheduling simulation system is built.Multi-topology and multi-data traffic simulations are carried out to verify the scheduling performance.The experimental results show that: under the premise that Time-triggered messages can be scheduled,using the Time-triggered Ethernet optimization scheduling technology based on rapid increments,the average end-toend delay of rate-limited messages is reduced by 14.08%,and the worst end-to-end delay is reduced by 22.86%.The technology significantly improves the service quality of Time-triggered Ethernet transmissions and fully meets the application requirements of safety-critical electronic systems.