Journal of the Institute of Electronics Engineers of Korea SC (전자공학회논문지SC)

The Institute of Electronics and Information Engineers (대한전자공학회)
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An Improved Tracking Servo System in Optical Disk Drives

광디스크 드라이브의 개선된 트래킹 서보 시스템

  • Lee, Tae-Gyu (Hanyang University, Department of Electrical Engineering) ;
  • Jeong, Dong-Seul (Hanyang University, Department of Electronics and Computer Engineering) ;
  • Chung, Chung-Choo (Hanyang University, Division of Electrical and Biomedical Engineering)
  • 이태규 (한양대학교 전기공학과) ;
  • 정동슬 (한양대학교 전자통신전파공학과) ;
  • 정정주 (한양대학교 전기제어생체공학부)
  • Published : 2007.07.25
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Abstract

An optical pick up generally has coupled dynamics between focusing and tracking servos. The coupled dynamics reduces tracking performance of optical disk drives. A conventional control method is holding the previous tracking control command in the presence of surface defect. The method has a long settling time. If the defective area is getting larger, objective lens will get away from the following track. In order to overcome this problem, this paper proposed a new control method for optical disk drives based on a prediction of tracking error and focusing error. We present how to compensate the coupled dynamics so that reduced setting time is achieved. It is verified by experiments that the proposed method brings an improved performance in the presence of surface defect as well as in the normal operating condition.

광디스크 드라이브에서 일반적으로 광 픽업은 포커싱과 트래킹 서보 시스템의 결합된 동력한 시스템을 갖는다. 이 결합된 동력학 시스템은 서로의 구동간섭에 의하여 광디스크 드라이브의 성능을 저하시킨다. 특히 디스크의 표면에 결함이 존재할 경우에는 포커싱과 트래킹 서보 시스템의 구동간섭으로 인해 시스템이 안정화하는데 많은 시간이 소요되고 결함구간이 길어질 경우 광학 렌즈가 추종하던 트랙을 이탈할 수 있다. 본 논문에서는 이 문제점을 극복하기 위하여, 트래킹 에러와 포커싱 에러의 관측을 기반으로 광디스크 드라이브의 새로운 제어 방법을 제안한다. 결함이 존재할 경우 결합된 동력학 시스템에 대한 보상을 통하여 시스템의 안정화 시간을 감소시킨다. 동일한 표면 결함에 대하여 제안된 제어 방법의 개선된 성능은 실험을 통하여 검증하였다.

Keywords

References

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