ADAPTIVE FEEDBACK LINEARIZATION OF NONLINEAR-SYSTEMS

After an examination of the restrictive assumptions that limit the applicability of existing adaptive nonlinear control schemes, new adaptive regulation and tracking schemes are developed for a class of feedback linearizable nonlinear systems. The coordinate-free geometric conditions, which characterize this class of systems, neither restrict the location of the unknown parameters, nor constrain the growth of the nonlinearities. Instead, they require that the nonlinear system be transformable into the so-called pure-feedback form. When this form is ''strict'', the proposed scheme guarantees global regulation and tracking properties, and substantially enlarges the class of nonlinear systems with unknown parameters for which global stabilization can be achieved. The new design procedure is systematic and its stability proofs use simple analytical tools, familiar to most control engineers.