抄録
Here the controller design method for a kind of nonminimum phase systems which sometimes appear in controller design problems for automobiles, aircrafts, or large scale systems is considered. In these cases a unstable zero which locates near the origin may limit the performance of the controlled system. Especially it is concerned that the proposed controller design method is such a one that the available closed loop performance is easy to see for a designer when he knows the location of the unstable zero. In the proposed method, the performance, disturbance attenuation, robustness and the location of the closed loop poles are taken account through loop-transfer function gain shaping with the clssical stability margin concept. To do so, the framework of H∞ mixed sensitivity problem is used and how to choose the frequency weights is proposed. This method can be applied to servo system design or plants having poles on the imaginary axis. And also undesirable pole-zero cancellation coming from the mixed sensitibity problem is prevented by proposed frequency weights choice.
