Browsing by Author "Chan, T. C."

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Friction effect on ball positioning of an automatic balancer in optical disk drives
(2012-09-01)
Chan, T. C.
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Sung, C. K.
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Chao, Paul C. P.
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影像與生醫光電研究所
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電機工程學系
This study was aimed at evaluating the perfect balancing position of an automatic ball balancer installed in optical disk drives taking into consideration the effects of the rolling friction, speed ratio, and scaling parameter on ball positioning. A mathematical model that is employed to derive the dynamic equations of the ABB system was constructed. Stability of the steady-state solutions was then analyzed. A numerical simulation and an experimental study were conducted to verify the mathematical model. The simulation and experimental results were in good agreement.
Influence of external excitations on ball positioning of an automatic balancer
(2013-11-01)
Sung, C. K.
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Chan, T. C.
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Chao, C. P.
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Lu, C. H.
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電機資訊學士班
This study examined the influence of external excitations on ball positioning in an automatic ball balancer (ABB) installed in a rotor system. The authors' previous studies adopted a model that considered the ABB as an autonomous system by neglecting external excitations. We examined how the magnitude, the frequency and even the phase of an external excitation affected ball positioning. Simulations were performed to predict the ball positions under various external forces. Then, we constructed an experimental rig by employing a shaker to apply excitations to the rotor system and the associated ABB to verify the theoretical development. Simulation results indicated that the balancing balls of the ABB could counterbalance the external force by the change of the ball positions. However, it was observed from the experiment that the ball would not be displaced if the external force was applied after the ball had been positioned because the excessive rolling resistance between the ball and the runway prevented the ball from moving to desired positions. (C) 2013 Elsevier Ltd. All rights reserved.
Non-linear suspension of an automatic ball balancer
(2011-03-01)
Chan, T. C.
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Sung, C. K.
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Chao, Paul C. P.
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
This study investigates the effects on ball positioning because of the non-linear suspensions of an automatic ball balancer (ABB) installed in a rotor system. A complete dynamic model of the ABB, focusing on the non-linearity of the suspensions, is presented. The elastic behaviour of these suspensions is assumed to be well characterised by equivalent non-linear springs. Herein, two Duffing-type non-linear springs are considered: stiffness-softening and stiffness-hardening. Four types of asymptotic solutions that represent the ball positions at steady state are obtained by employing the method of multiple scales. The stabilities of all four types of solutions were found using Floquet theory. In contrast to the perfectly balanced solutions (Type I), the other solution (Type II) is affected by non-linear stiffness suspension. After properly designing the avoidable level of non-linearity, the balancing balls of the ABB still resided at the positions required to reduce the expected vibrations in the steady state. Numerical simulations were performed to validate the theoretical results. The results were also used to predict the level of residual vibration, and design guidelines that would guarantee the desired performance of the ABB for high-precision applications were formulated. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.