Some problems in nonlinear output regulation

Nonlinear output regulation problem has been an important area in control theory and applications. Many methods and tools have been developed in recent years to deal with various nonlinear output regulation problems. However, many problems remain open. In this thesis, we address the following four topics in nonlinear output regulation.; Semi-global robust output regulation for minimum phase nonlinear systems. Semi-global robust output regulation problem for a class of minimum phase nonlinear systems is investigated by using a framework proposed recently by Huang and Chen. Under the framework, a robust output regulation problem for a given plant can be systematically converted into a robust stabilization problem for an appropriately augmented plant, thus setting a stage for solving the robust output regulation problem using a variety of stabilization techniques.; Semi-global output regulation for linear singular systems with input saturation. The solvability conditions for the semi-global output regulation problem of linear singular systems with input saturation are established. We show that, under some standard assumptions, we can convert a singular system into a reduced-order normal system by employing the familiar system equivalence technique.; Robust output regulation for discrete-time nonlinear systems . The robust output regulation problem for discrete-time nonlinear systems is investigated. Firstly, the solvability conditions for the discrete-time kth-order robust output regulation problem is established by using internal model principle. Secondly, in analogy to the continuous-time case, we develop a framework for solving the discrete-time robust output regulation problem.; Output regulation for discrete-time nonlinear systems using neural networks. We consider an approximate solution of the output regulation problem for discrete-time nonlinear systems using neural networks. The advantages of our approach are that it is much more efficient than existing approaches, and it can handle systems with uncertain parameters. (Abstract shortened by UMI.)...