Research On Scheduling Methods For Networked Control Systems Based On Game Theory

Networked Control System (Networked Control System, NCS), a special distributed control system using network as communication channel, is an inevitable trend in control area. Subject to the constraints of the hardware and technology, network conditions reach the desired level, so that there is time delay, data dropout and other issues inevitably exist in the system where multiple control loops share the same communications network. Thus, it leads to the decline in the dynamic performance of the system and even instability. Due to NCS is composed by communication network and the control system, its performance is not only determined by the control algorithm but also depends on the rational management of the limited network resources. The scheduling methods of NCS were studied to improve the overall performance of the system and maximize the utilization of network resources.First of all, an overview of research background, the basic structure, the application and the basic issues in NCS was given. Then the basic concept of NCS scheduling methods was introduced to lead to the problems need to be solved in the scheduling.In order to improve the control performance in NCS while efficiently use the limited network resources, a two-dimensional bandwidth and mixed priority scheduling strategy was presented to overcome the shortcomings in current scheduling policies, where the priority of the task and network bandwidth can be collaborative scheduled. Therefore, the execution order of the task was codetermined by its primary priorities and its secondary priority. Besides, the two-dimensional bandwidth control strategy was further introduced into the two-dimensional priority scheduling mechanism so that the network bandwidth can be dynamically adjusted according to user requirements, and overcome the existing network in real time in the two-dimensional priority scheduling mechanism further introduction of the two-dimensional bandwidth control strategy to overcome the existing network bandwidth dynamically adjusted in real time according to user needs, and thereby the network environment can be improved the network environment.Given the contention for limited network resources amongst the network nodes in NCS is a game process, a preliminary discussion for the allocation problem of network resources was made on non-cooperative game theory. On account of the NCS with constrained bandwidth resource, a non-cooperative game model for bandwidth scheduling was established to optimize network bandwidth scheduling. In addition, a easy implementation of priority feedback scheduling strategy was designed on the basis of assurance system high utilization of network resources. In this priority scheduling policy the sensors’priorities would be adjusted online according to the control performance of the control loops, and the overall control quality of the system would be greatly improved.Finally, the simulation experiments were conducted on TrueTimel.5simulation toolbox combined with Matlab/Simulink environment to verify the effectiveness of the proposed methods.