Robust output regulation for a class of linear differential-algebraic systems

This letter addresses the problem of robust output regulation of systems described by linear differential-algebraic equations (DAEs). Taking advantage of some recent relevant results concerned with the development of normal forms for general DAEs, it is shown how an internal model can be designed in such a way that the problem in question is reduced to the problem of robustly stabilizing an augmented system modeled by DAEs. Then, a suitable enhancement—within the context of systems modeled by DAEs—of the theory of extended observers is proposed, by means of which such robust stabilization problem is solved.