モード切り換え型制御系における初期値補償の最適化

Abstract

One of authors previously has proposed the Initial Value Compensation (IVC) method at mode switching for head positioning servo of magnetic disk drives. The basic consept of IVC is to cancel undesirable poles of the closed loop system by zeros. Zeros of the transfer function between the head position and the state variables of the plant and the compensator can be relocated by injecting suitable values to the state variables of the compensator at mode switching via the IVC gain. However, in the previous study, the class of relocatable zeros has not been clarified. Furthemore, the degree of freedom of the IVC gain has not been studied. In this paper, these problems are investigated. First, it is clarified that the class of relocatable zeros is concerned with zeros of the transfer function of the plant and poles of the transfer function of the compensator. Second, by using the degree of freedom of the IVC gain, the optimization method for zero-input responses is proposed. Finally, numerical results for the head-positioning servo system of the magnetic disk drives are given to show the effectiveness of our proposed method.