Exact output control for a family of linear plants with parameter uncertainties (Q1911252)

The investigated problem consists in finding a linear discrete-time compensator which, independently of the actual value of the parameter vector, guarantees zero continuous-time steady-state output error with respect to a given continuous-time external reference. The authors propose a possible solution to the exact tracking problem for an unknown linear plant, such that its solutions belong to a known, admissible, finite set. The proposed solution consists of a periodic controller given by the periodic switching among the deadbeat ripple-free controllers that can be designed for each possible configuration of a plant. The paper gives also solvability conditions in terms of internal model and structural properties of the plant, in both the discrete- and continuous-time domains.