Of three modes of compensation of a feedback control system, the feedforward is equivalent to feedback compensation and the feedback compensation has much wider applicability than in the series compensation when the physical realizability of the compensating element is considered. The originally given control system (uncompensated) of Fig. 3 can equivalently be transformed to the one shown in Fig. 7 (b), after making a proper feedback compensation as follows (Fig. 6)
H=
Go-
Gpwhere,
Go is a relatively simple transfer function to be defined by a designer and fulfils the following conditions:
_??_
Since the feedback loop appearing in Fig. 7 (b) contains very simple transfer elements, its characteristics can be thoroughly discussed. This means that synthesis of the feedback system from ν to
xo is relatively simple. Following this idea, the task of design of feedback compensation would become straightforward and exact. Specific requirements on the system output
x would demand some retouch on the form of
Go (
s) and/or on the parameter-selection of
Ge. This procedure is independent of the type of
Gc, which could be of any type such as on-off, P, PI, I, PID or sampling.
抄録全体を表示