Comments on Stein's postulated high-frequency behavior of H/sub infinity / optimal controllers

G. Stein (26th IEEE Conf. Decision Control, Los Angeles, CA, Dec. 1987) showed that H/sub infinity / controller designs often give very unrealistic high-frequency behavior. The polynomial systems approach to H/sub infinity / is used by the commenter to demonstrate that the high frequency gain of H/sub infinity / controllers can be made to fall off at any desired rate provided improper noise and weighting models are chosen.<
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