 
Summary: IEEE TRANSACTIONS ON AUTOMATIC COhTROL,M L . AC29,NO. 6. JUNE 1984 569
compensatorsystem plant loop has been shown in all of the papers on the
compensatorbased approach.
If x and w are not measurable, but the triple
is output feedback stabilizable, there exist matrices KO and K2 such that
the output feedback control *
u =  K,CAx"KO(F+CX)Ax,K,.xc (32)
regulates A x " and Axc to zero. We note that
C A x " + ( F + C X ) ~ x , = ! .  D u  ( F + C X ) x , , (33a)
or equivalently
Hence, the feedback control design (32) uses only the measurable quanti
ties in the servomechanism, namely )' and .x,.
Moreover, the closedloop matrix when (32) is used is given by
A  BKoC  BK,( F + C X )  BK2
l'CrYDrK&ZYD,K,(F+CX)YD,K, )' (34)
Given KO.and any arbitrary K;. there exists K2 such that
K ; =K 0 ( F + C X ) + K 2 . (35)
Thus, the feedback control (32) is equivalent to a feedback control for the
pair (30) which is given by
Au" KZAX,=  KOCAX"KiAx,.. (36)
