Robust resilient dynamic controllers for systems with parametric uncertainty and controller gain variations

One of the fundamental problems in feedback control design is the ability o f the control system to maintain stability and performance in the face of s ystem uncertainties. To this end, elegant multivariable robust control desi gn frameworks such as H-infinity control, L-1 control and mu synthesis have been developed to address the robust stability and performance control pro blem. An implicit assumption inherent in these design frameworks is that th e controller will be implemented exactly. In a recent paper by Keel and Bha ttacharyya, it was shown that even though such frameworks are robust with r espect to system uncertainty, they are extremely fragile with respect to er rors in the controller coefficients. In this paper, we extend the robust fi xed-structure controller synthesis approach to develop controllers which ar e robust to system uncertainties and non-fragile or resilient to controller gain variations.