Tracking Control For A Class Of Nonlinear Networked Control Systems

Control systems with feedback loop closed via a real-time shared media network are called networked control systems. It has advantages such as low cost, high reliability, easy installation and maintenance, etc. However, the insertion of communication network also brings some detrimental phenomena such as network-induced delay and data packet dropout, etc, which often affect the performance of networked control systems or even cause the systems instability. In addition, many plants in industry have nonlinear characteristics. T-S fuzzy models are able to approximate any smooth nonlinear function to any degree of accuracy. Hence, it is important to investigate the nonlinear networked control systems based on T-S fuzzy models in practice. On the other hand, tracking control is ubiquitous in dynamic processes, e.g., industry, biology, etc. Compared with the stabilization problem, tracking control is also important for practical applications. The main objective of tracking control is to make the state or output of the controlled plant track the state of a reference model or a given reference signal as close as possible in the requirements of the given tracking performance. The tracking control problem of discrete uncertain nonlinear networked control systems was investigated based on T-S fuzzy model in this paper.The main research works in the thesis are as follows:Chapter1, the research background and research situation at home and abroad of this thesis is introduced.Chapter2, the problem of robust tracking control for uncertain discrete nonlinear NCSs is investigated. By using an input-delay approach, a class of nonlinear systems is modeled as an uncertain discrete T-S fuzzy system. Based on Lyapunov stability theory, a sufficient condition for the existence of robust tracking controller that guarantees the given tracking performance is presented in terms of a set of LMIs with an upper bound and a lower bound of the time delay. Finally, a numerical example is given to demonstrate the effectiveness of the proposed method.Chapter3, the problem of output tracking control for uncertain discrete nonlinear NCSs based on the membership function deviation is investigated, discrete T-S fuzzy model is employed to represent uncertain nonlinear systems. Based on Lyapunov stability theory and LMIs approach, the H∞tracking control problem is transformed into feasibility problem of the LMIs. The linear matrix inequalities are solved to obtain the parameters of the controller. Finally, numerical example show the effectiveness of the proposed method.Chapter4, the main research works of the thesis are concluded, and some research issues in future are prospected.