Some Control Problems Of Networked Control Systems With Time-Delay

Networked control systems are closed loop control systems connected via a communications network. Such systems take full account of the delay problem among the data collections, controllers, actuators, and they have advantages of less wiring, resource sharing, low overhead easy installation and maintenance, etc... So in recent years, they have been widespread concern.Meanwhile, the control problem of nonlinear systems is a difficult task. Because the system exists the nonlinear problem and has a complex structure, which makes the analysis and design for the controller difficult. However, due to the appearance of the fuzzy system with IF-THEN rules, it has become one of the most effective solutions to complex system modeling method, which has the feature that in any accuracy, fuzzification complex nonlinear process. Thus, by T-S fuzzy model, nonlinear system can be made in accordance with the local linear model to form a smooth connection according to the fuzzy membership functions. Then, this method provides a general framework for the analysis of nonlinear system and controller design. Also, because in many practical control systems, especially in NCSs, the controlled object is continuous, but the controller is discrete, then the system can be described as a model input delay sampling system.Therefore, in the first and second chapter, this article introduces the related knowledge of the networked control systems, the sampling control, the tracking control, and the related content of the LMI, the fuzzy control theory, the parallel distributed compensation and the stability theory. In the third chapter, a class of sampling control method based on input delay approach has been researched, it draws the exponential stability and the Sufficient conditions of L2-gain, and the maximum transmission time delay to ensure that the system is stable. According to the numerical analysis, it demonstrates the effectiveness of this method. Also, this method is applied to the problem of the tracking control about the network control system in the forth chapter. Therefore, it has been applied in the forth chapter. In the forth chapter, the controlled object is described the T-S fuzzy model, the fuzzy controller is designed under circumstance of the gain matrix of known and unknown, and the reference model is a linear model. Using the input delay method, the controlled object status information each time has been tracked. While some properties based on the Lyapunov stability theory, the Jenson inequality and the convex function, by using the new scaling methods for solving the linear matrix inequalities, it draws the maximum transmission time delay to ensure that the system is stable so that the result has a lower conservative resistance, and meets the tracking performance. Finally, according to the simulation examples, we have drawn up the state response curves and the tracking error curves for the system, which illustrates the feasibility of this method.Finally, it has made the summary and the prospect for the whole article, pointed out the results of this study and the problem which have not overcome, and a clear future research direction have been made.