Two global regulators for systems with measurable nonlinearities and unknown sinusoidal disturbances

In this paper the class of nonlinear observable systems with known output dependent nonlinearities affected by disturbances generated by an unknown exosystem is considered. The output feedback set point regulation problem is solved by adaptively generating the reference input on line when both the parameters and the order of the exosystem are unknown and the resulting reference control input consists of a biased sum of sinusoids. Two global solutions to this problem are provided when only an upper bound on the exosystem order is known: the first scheme is simpler but is restricted to minimum phase systems while the second one can handle non-minimum phase systems as well and identify the exosystem parameters.