High-Bandwidth Servo Design for Shaping Primary Arm-Resonance in Magnetic Disk Drives

Abstract

In the head positioning control of magnetic disk drives, a bandwidth must be increased to meet greater performance demands. However, one of the barriers to achieving high-bandwidth is the effect of mechanical resonance modes. Accordingly, we have developed a method for designing a high-bandwidth servo controller that takes into account the mechanical resonance modes. This design method uses discrete-time H_∞ synthesis. It is shown that this method can increase the bandwidth by shaping the primary arm-resonance characteristic.