  We present a new direct adaptive control approach for nonlinear systems with
unmatched and matched uncertainties. The method relies on adjusting the
adaptation gains of individual unmatched parameters whose adaptation transients
would otherwise destabilize the closed-loop system. The approach also
guarantees the restoration of the adaptation gains to their nominal values and
can readily incorporate direct adaptation laws for matched uncertainties. The
proposed framework is general as it only requires stabilizability for all
possible models.
