B. Schwartz et al., Global normal forms for MIMO nonlinear systems, with applications to stabilization and disturbance attenuation, MATH CONTR, 12(2), 1999, pp. 121-142
A geometric characterization of a class of square invertible nonlinear syst
ems that can be molded into a normal form by a global diffeomorphism is det
ailed. Then additional conditions are fashioned that permit the implementat
ion of the recursive design method known as "backstepping."