1999 Volume 12 Issue 6 Pages 319-325
This paper proposes a design method of a robust controller with the ability to adjust control performances adaptively. The controller having a time-varying parameter is based on the parametrization of H∞ controllers. The time-varying parameter takes the place of the so-called Q-parameter to reduce a Lyapunov function of the resulting closed-loop system. This time-varying parameter changes according to the estimations of plant parameters which are derived from a realtime nonlinear calculation with a disturbance observer. The closed-loop system is guaranteed to be quadratically stable.