Abstract
We have developed a user-friendly loop-shaping method employing the Robust Bode (RBode) plot for optimizing an H∞ controller in a magnetic-head-positioning system of a hard disk drive. The RBode plot represents the robust performance criterion as allowable and forbidden regions on the controller Bode plot. As a result, control engineers can easily optimize an existing H∞ controller so that the control system gets the better performance against perturbations of the controlled object. In the proposed method, there is no need to construct the transfer function models of the controlled object and of the disturbance. Simulation results for a track-following control in the hard disk drive show the utility of the proposed method.
