• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.735-739
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• 2003

This paper presents a direct seek control algorithm for swing-arm type dual stage servo system that consists of a coarse actuator and a fine actuator. The proposed scheme is to design a control system that attenuates the effect of dynamic coupling between the two actuators so that the seek operation can be performed in a single-shot with stability. In an optical drive system with dual stage servo mechanism, the effect of dynamic coupling between the two actuators needs to be handled during the coarse seek operation due to its inherent structure. In an extreme case, the two actuators can collide each other, which leads to critical degradation of the seek performance. To handle this problem, our proposed control scheme is to generate the drive signals such that the two actuators behave as if they are a single fixed body. To this end, a feedforward controller and two feedback controllers are designed that enable the current drive system perform wide range of track seek. Simulation results are provided to show the validity and feasibility of our proposed algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.424-429
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• 2003

This paper proposes a swing-arm type dual-stage actuator, which consists of a PZT actuator for fine motion and a VCM(Voice Coil Motor) for coarse motion, for SFF ODD(Small Form Factor Optical Disk Drive), in order to achieve fast access speed and precise track following control. We focus our attention on the design and control of the PZT actuator, because there have been a lot of previous researches related to the VCM and dual-stage actuators. Due to the dual cantilever structure, the PZT actuator can generate precise translational tracking motion at its tip where optical pickup is attached at, and the effect of hysteric behavior of the PZT element is reduced. The dynamic model of the PZT actuator is derived by using the Hamilton's principle, and verified by comparing with the experimental frequency response. The sliding mode control is designed in order to be robust against modeling uncertainties. Simulations and experimental results confirm the effectiveness of the suggested control scheme.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.664-669
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• 2003

This paper proposes a swing-arm type dual-stage actuator, which consists of a PZT actuator for fine motion and a VCM(Voice Coil Motor) for coarse motion, for SFF ODD(Small Form Factor Optical Disk Drive), in order to achieve fast access speed and precise track following control. We focus our attention on the design and control of the PZT actuator, because there have been a lot of previous researches related to the VCM and dual-stage actuators. Due to the dual cantilever structure, the PZT actuator can generate precise translational tracking motion at its tip where optical pickup is attached at, and the effect of hysteric behavior of the PZT element is reduced. The dynamic model of the PZT actuator is derived by using the Hamilton's principle, and verified by comparing with the experimental frequency response. The sliding mode control is designed in order to be robust against modeling uncertainties. Simulations and experimental results confirm the effectiveness of the suggested control scheme.