An Improved Dynamic Gain Method to Global Regulation of Feedforward Nonlinear Systems

This article proposes an improved dynamic gain method for studying the global regulation problem of feedforward nonlinear systems. The uncertain nonlinear terms admit an incremental rate depending on an unknown constant and the input. With a transformation of the state, an output feedback controller and a state feedback controller are designed respectively, without resorting to the celebrated forwarding design method. Based on the Lyapunov analysis, it is proved that the global regulation of the closed-loop system is achieved. Different from most existing control constructs for feedforward nonlinear systems, a new time-varying function is used for the first time to design the controller with a dynamic gain, which improves the convergence speed of the system state. Through a simulation example, the advantages of the improved dynamic gain method are illustrated.