Research ArticleGlobal adaptive output feedback control for a class of nonlinear time-delay systems

- A universal-type adaptive output feedback controller is constructed to globally stabilize for nonlinear time-delay systems.
- The stability and convergence analyses are carried out using the Lyapunov theory.
- The efficiency of output feedback controllers is demonstrated by two simulation examples.

This paper addresses the problem of global output feedback control for a class of nonlinear time-delay systems. The nonlinearities are dominated by a triangular form satisfying linear growth condition in the unmeasurable states with an unknown growth rate. With a change of coordinates, a linear-like controller is constructed, which avoids the repeated derivatives of the nonlinearities depending on the observer states and the dynamic gain in backstepping approach and therefore, simplifies the design procedure. Using the idea of universal control, we explicitly construct a universal-type adaptive output feedback controller which globally regulates all the states of the nonlinear time-delay systems.