Research On Scheduling Of Transmission In CPS Network Based On Variable Sampling Period

With the improvement of people’s requirement about the intelligence of physical world, it’s an inevitable trend of developing to produce more interactive between the information world and the physical world, Cyber-Physical Systems are associated with this trend as demands of new age. It’s a new kind of intelligent complex system with computer, communication, controlling technology. CPS obtains the physical world’s information with sensor, and then the information is transmitted to the controller in the information world. With the controller’s computer, a command is generated and transmitted to the actuator, at last, the command is fed back to the physical world. In this process, the transmission of information is implemented through the network.Firstly, This thesis reviews the theoretical basis and the research status of CPS, and compares it with the traditional application systems. On this basis, we focus on the network in CPS, and several key factors which affect the network’s QoS, which lead to the problem to be solved in this thesis. On one hand, for a more accurate command, the controller requires the sensor to sample faster, but on the other hand, with the limitation of network’s resources, the data in the network can’t be too abundant, so it’s the work of this thesis to optimize the sampling period under the dual constraint.Secondly, we study the traditional scheduling strategy in CPS,and establish a model in Matlab to simulate it, then we summarize the advantages and disadvantages of them in CPS. On this basis, a multi-priority scheduling strategy is proposed, and with it, the information can be transmitted in a more flexible way in the network. Then in the framework of this strategy, in view of the characteristics of different components, we put forwards two algorithms with variable sampling period, and the network’s resources and the control performance are all considered.Finally, we analyze the strategy’s simulation. With the Truetime toolbox, we establish a CPS’s model with some control loops, and they share an Ethernet’s bandwidth. We compare our strategy with traditional algorithm, and the results verify the validity of the proposed method.