Adaptive observer for a class of MIMO non triangular uniformly observable nonlinear systems

An adaptive observer is proposed for a class of uniformly observable nonlinear MIMO systems involving some unknown constant parameters. Two main characteristics of the proposed observer are worth to be mentioned. The first lies in the fact that the exponential convergence of the proposed observer is guaranteed under a certain persistant excitation condition which is given. The second main characteristic lies in its capability to give rise to different observers among which adaptive high gain like observers and adaptive sliding mode like observers. This is achieved through the specification of a design function in the observer gain which is calibrated through the choice of a single scalar parameter. Simulation results are given in order to highlight the performance of the proposed observer.