Output regulation of linear systems with adaptive internal model

Given a controllable and observable linear system with additive disturbances and output reference generated by a linear stable exosystem with unknown parameters, the problem of designing an output feedback regulator which guarantees asymptotic regulation and disturbance rejection is considered. The system is assumed to be known while the frequencies of the exosystern are unknown. A global solution is proposed consisting of a dynamic output feedback controller, which includes exponentially convergent estimates of the unknown frequencies and of the reference control