Sliding-Mode Control For A Class Of Uncertain Nonlinear State-Delayed Systems

In the 1950s, Emelyanov, a Soviet researcher, first proposed variable structure control (VSC) based on sliding mode(SM), then Utkin and Itkis etc. developed the theory. Significant interests on VSC with SM have been generated in control research realm on account of its excellent robustness and complete adaptability to the uncertainties and external disturbance in the 1970s.So far, VSC with SM has been deeply studied as an important branch of nonlinear control theory. It has been applied to control discrete-time systems, distributed parameters systems and time-delay systems etc. However, the chattering with high frequency in sliding mode control systems is barrier for the application to the practice engineering problems. For this point, many advanced control theories, such as adaptive control and fuzzy control, have been applied to variable structure system to reduce the chattering.Firstly on the basis of many foreign and civil references, this paper introduces the basic theories and items, summaries the history, actuality and foreground of SVC.Secondly, a sliding mode controller (SMC) is constructed to drive the states to the proportional-integral (PI) sliding mode surface for a class of uncertain state-delayed systems with state nonlinear and input nonlinear. Based on this, a L₂ -L_∞state feedback controller is designed. A sufficient condition is proposed in terms of linear matrix inequalities (LMIs), which guarantees the sliding mode robust asymptotically stable and has a noise attenuation levelγin a L₂ -L_∞sense. A numerical simulation is given to illustrate the effectiveness and feasibility of this method.Finally, on synthesizing current methods and experience of reducing the chattering, which is the shortcoming of the sliding mode control systems, this thesis combines quasi-sliding mode control method and fuzzy control. The results of simulations show the effectiveness of reducing the high frequent chattering.