Adaptive stabilizing controller design for a class of uncertain feedforward nonlinear systems

This paper investigates the problem of global stabilization by adaptive state feedback for a class of feedforward nonlinear systems. Different from the existing results, the systems considered have unknown control coefficient with known sign. By introducing the state transformation, the new system is obtained which is convenient for control design. Then, the estimation law for the control coefficient is constructed, and the state feedback controller is proposed with the gain updated on-line. It is shown that the global asymptotic stability of the original system can be guaranteed by appropriate choice of the dynamic gain and the estimation law for the control coefficient. Finally, a simulation example is given to illustrate the correctness of the theoretical results.