Feedforward control with sampled-data polynomial based on triangle hold for track seek of hard disk drive

Abstract

This research proposes feedforward control techniques aimed at reducing the seek time in hard disk drives (HDDs). These techniques utilize a sampled-data polynomial approach based on a triangular approximation first-order hold (triangle hold) with a non-zero initial value. In the first proposed method, we developed a sampled-data polynomial that allows for arbitrary initial values of the acceleration trajectory. In the second proposed method, to reduce computational load, we employ an approximate initial value for the acceleration trajectory in the sampled-data polynomial. These methods improve the seek time of the magnetic-head positioning control system in HDDs, primarily because the triangle hold offers a faster response compared to the traditional zero-order hold (ZOH). Moreover, these methods improve the seek time over the conventional method with the causal first-order hold (CFOH) because the triangle hold reduces the amplitude of transient vibrations. Validation results for the track-seek control of HDDs demonstrate that the proposed methods effectively reduce seek time compared to conventional methods.