Robust adaptive H-infinity control using integral quadratic constraints

This paper introduces a new approach to robust adaptive H-infinity control. The main idea of the paper is to extend an existing approach to robust H control to allow for constant or slowly varying unknown parameters in an adaptive way. This is achieved by treating the presence of the unknown parameters as states resulting ill a bilinear nonlinearity. A copy of this nonlinearity is repeated in the controller and the presence of the repeated nonlinearity is exploited using a special integral quadratic constraint. (C) 2008 Elsevier Ltd. All rights reserved.