Robust direct adaptive control with least prior knowledge

A new, robust, discrete time, singularity-free, direct adaptive-control scheme is proposed with respect to a class of modeling uncertainties in this paper. Two key features of this scheme are that a relative dead zone is used, but no knowledge of the parameters of the upper bounding function on the class of modeling uncertainties is required, and no knowledge of the lower bound on the leading coefficient of the parameter vector is required to ensure the control law singularity free. Global stability and convergence results of the scheme are provided