ABSTRACT
We consider the multiobjective problem of ℋ ∞ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003067702/c6b3ff05-4348-45f5-97a1-acfe807326ca/content/eq646.tif"/> sub-optimal control with the controller constrained to achieve robust closed-loop regulation with respect to step inputs. Computable necessary and sufficient conditions under which the problem admits a solution are derived. When these conditions are met, explicit state-space formulae for a controller that solves the problem are given. In particular, if robust regulation of ℓ outputs is desired, the controller we exhibit is of McMillan degree ℓ in the state feedback case. In the output feedback case, the controller we exhibit is of McMillan degree no greater than (n - ℓ), where n is the order of the plant.
