On the class of all stabilizing regulators

An alternative characterization is given of the class of stabilizing regulators which is convenient to achieve online or offline H/sup 2//H/sup infinity / optimization for performance and robustness. The characterization uses disturbance signal reconstruction and nulling filters. The theory allows a reinterpretation of the necessary and sufficient conditions for regulation. Also, connections between structurally stable regulation and the internal model principle are exposed.<
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