| Wireless networked control systems,with the advantages of large flexibility,low cost,high security,ease of installation and maintenance,is a key enabling technique for promoting the development of IIo T.WNCS has a wide range of applications in many scenarios consisting of real-time control system,such as industrial automation,automotive electronics,avionics,building management,etc,which indicates the application of WNCS will bring enormous development opportunities to wireless communication.One of the important research fields of WNCS is the design on scheduling schemes of transmission,which is of great significance to reduce resource consumption,promote system performance and ensure the normal operation of the system.A mass of work has been done on the research of transmission scheduling schemes,but most of them designed the schemes separately from a communication or control perspective.For example,the design from a communication perspective mainly meets the control performance requirements by providing ultra-high quality of service,which consumes lots of resources.The design from a control perspective directly targets the control performance,ignoring the influence of communication system,which is difficult to apply in practice.Hence,to address the shortcomings of existing schemes,this thesis proposes new transmission scheduling schemes by integrating communication and control,which could further reduce resource expenditures and obtain better system performance.Firstly,by analyzing the relationship between the actual state and the estimated state of the plant in WNCS,and comparing it with the AWGN channel model in communication system,this thesis introduces the mutual information into the control system.Based on that,a transmission scheduling scheme is proposed,which utilizes the mutual information between the actual state and the estimated state to evaluate the deviation between them.In order to determine the upper bound of mutual information,this scheme defines the concept of state-to-noise ratio by analogy with signal to noise ratio in communication systems,and takes it as the decision criteria of event triggering.Compared with the traditional schemes,this scheme can greatly alleviate the resource overhead and hardware requirements as well as maintain good control performance.Furthermore,to tackle the problem that existing transmission scheduling schemes do not fully consider the communication constraints,this thesis designs a transmission scheduling scheme based on the integrated design of communication control.In this scheme,taking account of the constraints on control system and communication system,the optimization problem with the goal to minimize the total cost of the system is constructed while the triggering decision of is treated as the optimization variable.In particular,the optimization problem is further simplified by utilizing the optimal control policy and resource allocation.Finally,this thesis proposes an algorithm to solve the optimization problem,and obtains the optimal transmission scheduling scheme corresponding.Through numerical simulation,the correctness and effectiveness of the schemes designed in this thesis can be verified,especially their advantages on improving the system performance and reducing the difficulty of practical deployment and application compared with the traditional scheme. |
