Implicit adaptive observers for a class of nonlinear systems

The authors propose a nonlinear adaptive observer for joint state and parameter estimation with global convergence. The considered class of nonlinear systems is the one originally considered for the design of high gain observers with an additional term involving a single unknown parameter. It is the fruit of mixing techniques of high gain observers, implicit observers in the form of differential-algebraic equations, and of some new idea for implicit adaptive observers. Potential applications of such adaptive observers are fault detection and isolation, and adaptive control