ADAPTIVE NONLINEAR DESIGN WITH CONTROLLER-IDENTIFIER SEPARATION AND SWAPPING

We present a new adaptive nonlinear control design which achieves a co mplete controller-identifier separation. This modularity is made possi ble by a strong input-to-state stability property of the new controlle r with respect to the parameter estimation error and its derivative as inputs. These inputs are independently guaranteed to be bounded by th e identifier. The new design is more flexible than the Lyapunov-based design because the identifier can employ any standard update law gradi ent and least-squares, normalized and unnormalized. A key ingredient i n the identifier design and convergence analysis is a nonlinear extens ion of the well-known linear swapping lemma.