An adaptive controller for a class of high-order nonlinear systems with unknown control coefficients

In this paper, a valid approach is successfully addressed to design the adaptive stabilizing control law for a class of high-order nonlinear systems with unknown control coefficients and in triangular form. For such control systems, the state-feedback stabilizing control has been investigated recently under the assumption that the lower bounds of the control coefficients are precisely known. This paper removes such assumption, and gives the recursive design procedure of stabilizing control law by employing the approach of adding a power integrator together with adaptive technique to the appropriately defined unknown system parameters. The designed state-feedback adaptive control law, which vanishes at the origin, guarantees that the states of the closed-loop system are globally asymptotically stable, while all the other signals are uniformly bounded.