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Active runout cancellation for fine‐seeking control in optical disk drives
Author(s) -
Liu JiengJang,
Yang YeePien
Publication year - 2007
Publication title -
optimal control applications and methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.458
H-Index - 44
eISSN - 1099-1514
pISSN - 0143-2087
DOI - 10.1002/oca.836
Subject(s) - settling , track (disk drive) , compensation (psychology) , servo , settling time , control theory (sociology) , servo control , control (management) , hard disk drive performance characteristics , engineering , computer science , control engineering , mechanical engineering , step response , artificial intelligence , psychology , environmental engineering , psychoanalysis , computer hardware
The fine‐seeking control, one of the radial positioning servo functions on the optical disk drives, seeks a limited number of tracks forward or backward. Two properties, noted as controllable seeking velocity and achievable settling, are important issues for fine‐seeking performance. Unless these performances are satisfied, the settling down track cannot be guaranteed to be the desired track; hence, additional seeking is required to come forward to the destination track. Owing to the periodic runout effects, the conventional feedback approaches are difficult to achieve stable velocity control and satisfactory settling performance for high spindle speed operation. This paper proposes the extended usage of frequency adaptive control technique (FACT) for active runout suppression on fine seeking. It is shown that the runout effects can be isolated from the servo systems as long as the FACT is applied. A mode switching control approach is then introduced to switch the adaptation between the track‐following and fine‐seeking processes. This leads to an efficient compensation for periodic runout, thereby eliminating the direction hysteresis in fine seeking. Experimental results are shown to be effective for the performance on both velocity control and settling behavior after seeking. Copyright © 2007 John Wiley & Sons, Ltd.