It is argued that J. C. Doyle's (Proc. ACC, p. 1691-8, 1986) criticisms reveal significant misunderstanding of quantitative feedback theory (QFT). Doyle's examples, claimed to be QFT-incompatible, can be handled using QFT with vastly more economical loop compensators than Doyle's designs. The QFT infinite-frequency condition, charged by Doyle to be highly restrictive, is shown to be necessary for all linear time-invariant (LTI) compensation techniques for achieving even moderate feedback benefits. In all available comparable designs, QFT has been more economical than other LTI ones.
|Number of pages||6|
|Journal||Proceedings of the American Control Conference|
|State||Published - 1987|