Parameter Identification Technique based on Lyapunov Stability

A system identification technique is presented for estimating the parameters of a class of nonlinear systems. An identifier is described which estimate the parameters using system measurements. A robust parameter update law is given based on the theory of Lyapunov stability which not only stabilizes the identifier but also handles the system uncertainty. To show the validity of technique, aerodynamic derivatives of fighter aircraft A-4D are estimated. Subject to this problem, a modeling based step-wise procedure is described. Instead of estimating all derivatives at once, groups of derivatives are estimated in steps.