A FINITE-ENERGY PROPERTY OF STABLE INVERSION TO NONMINIMUM-PHASE NONLINEAR-SYSTEMS

Stable inversion is a completely new approach to the output tracking c ontrol of nonminimum phase nonlinear systems, It not only offers exact reproduction of a given reference output trajectory but also guarante es: stability of all external and internal signals, After a brief revi ew of the stable inversion problem, the paper establishes a finite ene rgy property of stable inverses. That is, out of infinitely many possi ble inverse solutions, the one provided bg the stable inversion proces s is the only one that has finite energy, or, the L-2(-infinity, +infi nity)-norm, The effectiveness of the stable inversion approach in outp ut tracking as compared with the well-known classic inversion and nonl inear regulation approaches is demonstrated by working out an example of a nonlinear nonminimum phase system.