Robust output feedback control for a class of nonlinear systems

This paper investigates the problem of robust output feedback stabilization for a family of uncertain nonlinear systems. The proposed method contemplates uncertainties and results in asymptotic stability of system errors. The proposed method relaxes the debility of existing researches where the system nonlinearities are assumed to be bounded by a function of system output. In this note, the system nonlinearities under consideration are required to be bounded by a known function of state (not the system output), additionally no restrictive assumption is made on the system uncertainties. As some examples, the method is applied to two different control systems: the output feedback control of an atomic force microscopy as an example of chaotic systems; and the speed control of DC motors with only measurements of the armature current (not the shaft speed).