A Generic Internal Model for Robust Output Regulation Problem for Plants subject to an Uncertain Exosystem*

The canonical internal model is the key technique for handling the robust output regulation problem of systems with an uncertain exosystem. However, the output mapping of this internal model relies on the uncertain parameters of the exosystem. These uncertain parameters in the output mapping have to be further estimated using the adaptive control technique, which complicates the design of the overall control law. In this paper, we consider constructing a so-called generic internal model (gIM) which has the same form as the canonical internal model but with an output mapping independent of the uncertain parameters of the exosystem. With such an internal model, the robust output regulation problem for systems with an uncertain exosystem can be solved solely by the robust control approach, which is much simpler than the control law based on the adaptive control approach. We give conditions for constructing such gIMs.