ON THE EFFECT OF PERTURBATIONS ON THE STABILITY OF INPUT-OUTPUT LINEARIZING CONTROLLERS FOR A CLASS OF DISCRETE-TIME NONLINEAR-SYSTEMS

An analysis of the effect of parameter perturbations on the stability of input-output linearizing controllers for a class of MIMO discrete-t ime nonlinear systems is presented. A static-state feedback is designe d to input-output linearize a system without perturbations, and it is applied to the same system with an uncertain parameter vector, thus in troducing an uncertain parameter term in the nominal input-output line arized system. It is shown that the state trajectories of the closed-l oop perturbed system are ultimately bounded provided the closed-loop n ominal system is exponentially stable and some conditions on the bound s of the perturbation terms are satisfied. (C) 1998 John Wiley & Sons, Ltd.