Stability Analysis Of Networked Control System Based On Switching System Processing Method

Networked control systems are distributed control systems in which sensors actuators, controllers, and other units communicate with shared communication network. Unlike conventional modes of control systems, the networked control systems are of a series of benefits, such as wide distribution of controlled objects, high level of application, easy maintenance and so on. Network-induced delay and packet loss are the two most important issues of the theoretical analysis.Switching systems are described as effective models that can be used to solve the problem of building molds of variable delay and uncertainty complicated packet loss of networked control systems. By timing case analysis, the actual systems in different situations described as different subsystems, ultimately switching between different variability reflects the different delay and packet loss. This approach is more effective to reflect the specific characteristics of the network, and the model is more accurate, helping to reduce the conservatism of study.This thesis is concerned with the modeling, stability analysis and control for networked control systems with network-induced delay, using switching systems theory. The main achievements are as follows:(1)The detailed summary of some basic contents、issues and recent works on network control systems is made. Introduce the basic mathematical theory and the theory describing the switching systems, norm, etc.(2)Considering the networked control systems with short time delay, sensors are driven by time, the controllers are driven by event, the actuators are driven by time, but the actuators read control signal more frequently than sensors sampling, the form of controllers is state feedback. In this mode of operation, through the analysis of the role of a sampling period of the control signal, discrete objects will be charged to obtain a switching system model with limited sub-systems.(3)According to the established model, select a adequate Lyapunov function. At first, according to the relationship of the Lyapunov function between the various subsystems, with time going on, get the exponential inequality; secondly, as the system states can not be mutated at the switching time, get the exponential inequality; and finally, introducing the concept of the average dwell time, with the above two steps gradually get the exponential inequality of switching system. Under the premise of zoom factor less than one, determine the average dwell time. Then according to norm theory, get the exponential inequality of the above process and the conclusion of the stability in the condition that the system-shrinkage rate is less than one. At last, analyze the relationship between this conclusion and the traditional criterion of Lyapunov.(4)According to the models of switching systems and stability conditions, introduce the mean to devise the controllers. By analysis the relationship between shrinkage percentage and the stability of switching system, the problem of controller design is transformed into solving the controller parameters so that the shrinkage percentage is minimal. Finally use genetic algorithm to get the controller parameters.(5)Finally, put up the summary to the full text and propose some forecasts to the future research.