Stability of adaptive control in the presence of input disturbances and H∞. performance

Adaptive control in the presence of input disturbances is considered. It is shown that standard adaptive control algorithms can stabilize the system in the presence of input disturbances and guarantee an ℒ2-gain bound. This method allows one to guarantee the performance of the adaptive control even before the adaptive parameters converge to their optimal values. The results are obtained for linear systems with polytopic type parameter uncertainties. Static output-feedback as well as state feedback are considered. The computational efficiency of the results is also discussed. An illustrative example is given.