Research And Implementation Of Scheduling Strategy For Industrial TTE

Time-triggered Ethernet is a new type of real-time Ethernet protocol,which is widely used in aerospace and other systems with high reliability and real-time requirements.However,currently time-triggered Ethernet uses an offline scheduling table generation algorithm,and the protection time for time-triggered messages cannot be dynamically adjusted with network changes.If the protection time of time-triggered messages is too long,network link resources are wasted,or the protection time of time-triggered messages is insufficient,resulting in time-triggered message conflicts.On the other hand,there is a problem with the transmission of rate constrained messages that insufficient stability and reliability.Therefore,the main work of this thesis is as follows.Firstly,this thesis analyzes and researches the scheduling table generation algorithm of time-triggered Ethernet.According to the basic principle of time triggered Ethernet scheduling table generation algorithm,a dynamic scheduling table generation strategy based on time delay error is proposed.The scheduling strategy dynamically reserve time synchronization error protection time for each TT message according to the time synchronization error in the current network,by mathematically modeling time-triggered messages and constructing constraints,then brought into the Satisfiability Modulo Theories solver to dynamically generate a schedule for each basic cycle,completes the configuration of the schedule table in the Time-triggered Ethernet network by issuing the schedule table configuration lastly.On the other hand,the scheduling strategy divides the basic period of Time-triggered Ethernet into synchronous communication period and asynchronous communication period.By dynamically adjusting the proportion of synchronous communication period and asynchronous communication period,the time triggered message and best efforts message are transmitted in partitions,so that make the RC message have different priorities in different communication periods to guarantee the stability and reliability of RC messages.Secondly,according to the proposed dynamic scheduling strategy and the existing hardware equipment in the laboratory,an industrial Time-triggered Ethernet experimental system is built.From the perspective of practical application,this design scheme designs and implements the protocol for the industrial TTE master station and industrial TTE slave station by analyzing the different data requirements such as input and output data,discrete data and alarm data in the industrial network,including the scheduling mechanism,including the realization of the scheduling mechanism and the realization of the device network service.Finally,through the analysis of the data of the built experimental system,the results show that the scheduling strategy proposed in this thesis can dynamically complete the configuration of the scheduling table in the industrial TTE network,and realize the normal operation of each network service function.And the scheduling mechanism can separate the synchronous communication period from the asynchronous communication period to ensure the stability and reliability of TT messages and RC messages in the industrial TTE network.