To avoid worsening of control stability, disturbance restrainability, and the like by composing a transfer function of one path in a control system of an approximate model lowered in dimension and coinciding with a transfer function of the same path in a frequency range where target value follow-up performance is demanded.
A control frequency range where target value follow-up performance is demanded in a general servo system is determined of itself, and there is no problem from the viewpoint of control as long as a transfer function Gs' of an approximate model coincides with a transfer function Gs originally used in this frequency band. It is therefore so determined that the target value follow-up performance is flat in OdB. The approximate model of a transfer function, a control object, is composed of a part P surrounded by a dashed line, and the transfer function Gs' of a model lowered in dimension compared to the transfer function Gs of a part surrounded by a conventional dotted line is used. In association with this, a normative model Gm' of target value follow-up performance can be reduced in order compared to conventional Gm in a range of ensuring properness of a feedforward compensator Gm'/Gs'. Target value follow-up performacne can therefore be maintained satisfactorily.
KAMITSUMA FUMIHIDE
KUBOKAWA NORITADA
SUGIMOTO BUNICHI
