Adaptive control of triangular systems with nonlinear parameterization

The paper deals with adaptive control of uncertain nonlinear triangular systems whose uncertainty is characterized by nonlinear parameterization of unknown constant vectors. Robust adaptive control techniques are incorporated in the backstepping control design with flat zones to tackle the nonlinear parameterization together with a novel smooth projection algorithm for parameter estimation. The proposed algorithm guarantees the global boundedness of all the variables and the convergence of the tracking error to any prespecified small limit