Comprehensive Analysis Of Network Control Systems Based On Advanced PETRI Networks

As the rapid development of sensing,communication and computer network technology,research on networked control systems has been increasingly concerned.NCSs are a class of complicated control systems in which the components such as controllers,sensors and actuators are spatially distributed and connected via computer network.It is the very structure characteristic that makes network control systems with low repair and maintenance cost,high flexibility,increased distribution area of controlled node and facility to design large-scale control systems,etc.Different from the traditional point-to-point direct control system,such benefits of NCSs have made it more widely applied to large industrial process control systems in practice.At present,the network control systems have become a hot research direction in the field of international control,and has great theoretical significance and practical background.How to cope with the problem of modeling and analysis of the network control systems become an important branch of research direction.Simply relying on mathematical tools will make the exploration of networked control systems too limited to solve the problems of the broader field,especially for some complex systems that are difficult to use mathematical model to depict,traditional mathematical modeling methods are already ineffective.Computer science and control science subject can mix into a interdisciplinary that just provides a new solution for the study and opens up a new perspective of research on networked control systems,Petri net is the earliest modeling technology that combines computer theory with control theory to analyze the problem.Petri Net is a visual language,focusing on the various state changes and the relationship between them,which aims at studying the organizational structure and dynamic behavior of model system.In this paper,Petri net is used to formalize the modeling of networked control system,and based on properties of it,the delay in networked control system is analyzed.computer network communication technology and modern control technology are used to analyzes transmission problems existing in the networked control system,in addition,a solution making it stable is put forward after analyzes the main factors affecting the reliability of the network transmission system.The main innovations are as follows:1?In this paper,hierarchical reservation modeling is applied to the networked control system.The top-down modeling method of Petri net is used to refine the controllers,sensors and actuators and refine them step by step.And the network transmission delay is randomly distributed over a certain period of time,rather than a fixed transmission time.The packet loss and out-of-order model is also designed.The network delay is calculated using the token-based timestamp algorithm.2?Based on the advanced Petri net model of networked control system,the network delay data is extracted and analyzed.Firstly,the hidden Markov model is established by using B W algorithm,and the stochastic properties of Markov processes in the networked control system are further verified.Secondly,the hidden Markov model is applied to the next state delay estimation.Finally,the delay of the next system state in the advanced Petri net model is compared with the probabilistic time delay estimated by Hidden Markov Model.3?Finally,for the Hidden Markov Network Control Systems with Bernoulli packet dropping phenomenon,the stability analysis of the system is analyzed by the Lyapunov stability theory of the control system,and the system stability is analyzed for the zero disturbance and disturbance Zero system state,respectively.It proposed system stability criterion theorems,and further through the LMI method to determine the mathematical proof of theorem,and the H? filter of system is designed.