Disc drive dynamics identification using synchronous excitation signal

摘要

A method and system for identifying the resonance characteristics of a disc drive. A repetitive excitation signal is applied to the actuator assembly. The repetitive excitation signal has a period substantially equal to a positive integer multiple of a period of revolution of the disc. The position of the read/write head relative to a target track on the disc surface is sensed. The sensed position of the read/write head is compared to a desired position of the read/write head and apposition error signal indicative of the difference between the sensed position and the desired position is generated. The position error signal is time averaged over multiple revolutions of the disc to obtain an averaged repetitive position error signal. The resonance characteristics of the drive is determined based on a correlation of the averaged repetitive position error signal with respect to the repetitive excitation signal.