A disturbance observer approach to detecting and rejecting narrow-band disturbances in hard disk drives

This paper presents a servo compensator to detect and reject narrow-band disturbances in the non-repeatable runout (NRRO) for hard disk drives (HDDs). A disturbance observer (DOB) with a band-pass Q filter is used to detect the presence of the narrow-band disturbance. Once the disturbance is detected, the frequency of the disturbance is identified by the least mean squares (LMS) algorithm. Based on the frequency estimate, a narrow band-pass Q filter centered at the estimated frequency is applied to the DOB to compensate for the disturbance. The performance of this compensator is demonstrated by simulation on an open-source realistic hard disk drive model.

[1]  S. Nakagawa,et al.  A phase-stabilized servo controller for dual-stage actuators in hard disk drives , 2002, Digest of the Asia-Pacific Magnetic Recording Conference.

[2]  Masayoshi Tomizuka,et al.  Adaptive rejection of the dominant frequency components of non-repeatable runout in hard disk drives , 2007, 2007 European Control Conference (ECC).

[3]  Hiroshi Fujimoto,et al.  Proposal of perfect tracking and perfect disturbance rejection control by multirate sampling and applications to hard disk drive control , 1999, Proceedings of the 38th IEEE Conference on Decision and Control (Cat. No.99CH36304).

[4]  Abdullah Al Mamun,et al.  Hard Disk Drive: Mechatronics and Control , 2006 .

[5]  M. Tomizuka,et al.  Repeatable runout compensation for hard disk drives using adaptive feedforward cancellation , 2006, 2006 American Control Conference.

[6]  Gunhee Jang,et al.  New design of a HDD spindle motor using damping material to reduce NRRO , 2000 .

[7]  Masayoshi Tomizuka,et al.  Adaptive and Optimal Rejection of Non-Repeatable Disturbance in Hard Disk Drives , 2005, AIM 2005.

[8]  Masayoshi Tomizuka,et al.  Improved track following in magnetic disk drives using a disturbance observer , 2000 .

[9]  Masayoshi Tomizuka,et al.  Pivot Friction Compensation Using an Accelerometer and a Disturbance Observer for Hard Disk Drives , 1997, 8th International Symposium on Information Storage and Processing Systems.

[10]  William C. Messner,et al.  A novel disturbance observer design for magnetic hard drive servo system with a rotary actuator , 1998 .

[11]  Guoxiao Guo,et al.  Midfrequency disturbance suppression via micro-actuator in dual-stage HDDs , 2002 .

[12]  Youyi Wang,et al.  Optimal Narrow-Band Disturbance Filter for PZT-Actuated Head Positioning Control on a Spinstand , 2006, IEEE Transactions on Magnetics.

[13]  M. Tomizuka,et al.  Comparison of four discrete-time repetitive control algorithms , 1993, IEEE Control Systems.