Design Of Scheduling Algorithm And Generation Tool For Time-Triggered Ethernet

As the data-driven industrial ecology develops,the transmission speed,real-time,reliability and security of network communications for industrial control networks are more demanding than ever before.Time-triggered Ethernet(TTE),as a new hybrid transmission network technology,introduces time-triggered mechanism,synchronization mechanism and security mechanism into the traditional Ethernet,providing services for applications with different real-time and security requirements on a single physical network.Therefore,it has been obtained attention and recognition by industry and has been gradually used in aviation,aerospace,automotive and other fields.The thorough research is launched in this thesis about scheduling algorithm of time-triggered(TT)services,and a new scheduling algorithm is proposed.Further,a new scheduling table generation tool is designed and implemented.Based on this tool,the function and performance of the proposed scheduling algorithm are verified and analyzed.Firstly,the main mechanisms of TTE are introduced,including its architecture,network topology,communication model,synchronization mechanism and security mechanism,thus to clarify the research significance of scheduling algorithm and the collaborative relationship between scheduling mechanism and other mechanisms of TTE.Next,the scheduling ways,optimization ideas and solving methods of the existing scheduling algorithms are analyzed and summarized.In the partition scheduling way,the TT services are transmitted back-to-back,making the transmission delay of rate constrained(RC)services become too large.While in the porosity scheduling way,the TT services are transmitted with blank intervals,resulting the low channel utilization.Aiming at this problem,a scheduling algorithm based on collision decomposition is proposed.A decomposition scheduling way is used in this algorithm,in which TT services are divided into multiple subsets and scheduled in turn.The porosities of TT services in every subset are as small as possible to reduce the transmission bandwidth waste.And the scheduling of TT services in different subsets are separated by time to reserve bandwidth for RC services.Meanwhile the group-scheduling mechanism is used in this algorithm to reduce the complexity of solving.Further,the designing of pre-process,subsetting strategy,grouping strategy and backtracking strategy makes the algorithm more efficient and flexible to apply into different application scenarios.Then,the research and development needs of TTE for the scheduling table generation tool are analyzed carefully.And a user-friendly generation tool is designed and implemented to make users easy to build the network model and check the scheduling results.The system structure of the tool is divided into two modules,one module is network and services generation,and the other module is scheduling.And a network description file is designed to transfer the network model built by user in the former module to the latter,making the tool easy to integrate other scheduling algorithms.Finally,based on the generation tool,a simulation testing environment of TTE is built.The tests in various services scenarios validate the correctness and effectiveness of the scheduling algorithm.The results of tests show that the proposed scheduling algorithm is not only flexible and efficient enough to deal with the large-scale scheduling,but also can balance the transmission of TT services and RC services according to different application scenarios.It follows that the proposed scheduling algorithm in this thesis can better meet the scheduling needs of TTE,and the designed scheduling table generation tool can be directly used in practical engineering of TTE.