Adaptive stabilisation of extended nonlinear output feedback systems

The paper deals with the adaptive stabilisation for a class of uncertain no nlinear systems whose nonlinear terms are functions of two state variables. The uncertainty is parametrised by an unknown constant parameter vector af fined to smooth nonlinear functions. The model format considered in the pap er can be viewed as an extension to the standard output feedback systems wi th nonlinear terms of the single output which has been extensively studied recently. Based on the principle of adaptive backstepping design, an adapti ve control algorithm is proposed to stabilise the system in a feasibility r egion, using the feedback of the system output which is a vector containing the two state variables.