Comments on review by Prof. P.D. Roberts of ´Dynamical Hierarchical Control´

In an otherwise balanced and erudite review of the revised edition of my book ´Dynamical hierarchical control´ \IEEProc. D, Control Theory & Appl, 1982, 129, (5), p. 211], the reviewer (Prof. P.D. Roberts) pointed out that my statement in Chapter 3 that the 6th-order dynamical nonlinear example of two coupled synchronous machines was the highest-order nonlinear dynamical problem that had so far been treated by hierarchical techniques was false probably when the first edition was published (1977) and certainly when the second one was published (in 1980). I certainly have not seen a higherorder nonlinear dynamical problem treated by hierarchical techniques in the mainstream literature, up to the end of 1979 when the revised edition went to the press. The reviewer´s words ´but the statement is certainly false at the time of the second edition, which itself contains an example of a 20th-order system consisting of 11 coupled machines, albeit using a linearised model´ are misleading, since my statement in Chapter 3 obviously dealt with nonlinear problems treated as such and not with linearised versions of the same.