The Modeling And Control For Three Kinds Of Networked Control Systems

Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCSs).In NCSs, the communication between sensors, actuators, and controllers occurs through a shared band limited digital communication network. Recently, much attention has been paid to the study of stability analysis and controller design of NCSs due to their low cost, high efficiency, simple installation and maintenance, and high reliability and flexibility. However, the insertion of the communication channels raises new interesting and challenging problems such as quantization, sampling, time delays, and packet dropout. Therefore, NCSs have been a hot research topic for the high value of theory and application.In this paper, some work has been done on the several hot topics in NCSs field.Firstly, a new method is proposed to obtain the maximum allowable delay bound (MADB)of multi-input and multi-output (MIMO) networked control systems.Due to the fact that the network-introduced delays are distributed, the whole networked control systems (NCSs) are actually systems with multiple delays.The delay-dependent sufficient condition on asymptotical stability of NCSs is derived using the Lyapunov second method. Both the MADB and the output feedback stabilizing controller can be obtained by solving linear matrix inequalities (LMI).Secondly, based on static scheduler, a method of modeling for multi-packet transmission networked control systems (NCS) with short delay is presented. The NCS is described as linear switched systems model under certain switching sequences. By switched system theory and robust stability theory,both asymptotic stability criterion for stability of NCS with multi-packet transmission and the method of designing periodically dynamic output feedback stabilization controller are obtained. Based on dynamic scheduler, the NCS is modelled as linear switched systems under arbitrary switching sequences. By switched systems and H∞theory,the sufficient conditions for H∞performance of NCSs with multi-packet transmission are obtained. Further more, optimal H∞state feedback controller can also be designed based on the criterion for stability analysis.At last, we consider a class of NCSs with norm-bounded uncertainties. Using the continuous modeling method, the NCSs can be described as delayed differential equations, which can be viewed as a general form of the NCSs model, where the effect of the network-introduced delay and data packet dropout are simultaneously considered. Robust exponential stability criterion is derived based on a delay dependent method. Robust output feedback controller can also be determined by solving a set of linear matrix inequalities.