Mechanical Component Dimension Tolerance and Damping Effect on Controller

In HDDs, there are some notch filters which are used to compensate mechanical high frequency vibration from components. A range of error-rejection transfer function within the servo control loop is employed to depress such vibration. The advantage of such approach is to improve data rate performance. Two major factors associated with each frequency, that is, phase and gain. Due to many sub-components, such as HGA, carriage, pivot and VCM, etc., any condition change, such as dimension, young modulus, temperature, will change transfer function frequency and phase. In this paper, a specified error rejection gain induced failure drives are studied to analyze effect of mechanical component tolerance and damping effect on controller effectiveness