Browsing by Author "Sung, C. K."

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A Hula-Hoop Energy-Harvesting System
(2011-10-01)
Lu, C. H.
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Wang, Y. J.
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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
This paper proposes a hula-hoop energy-harvesting system that integrates a hula-hoop motion transformer with an electromagnetic generator. The hula-hoop motion transformer converts the linear motion from environment, machinery, or even human body into rotational one under specifically designed dynamic conditions. Then, the system can generate power through electromagnetism after combining the electromagnetic generator with the rotational motion. The equations prescribing the relation between induced voltage and power for the system are derived according to Faraday's theory. Meanwhile, the physical model of energy-harvesting system is established and the governing dynamic equations are derived as well via the Lagrange's equations. Good agreement of induced voltage and power between theoretical and experimental results is obtained. The maximum power that the system can generate is approximately 5 mW when the frequency and amplitude of the external excitation are 8 Hz and 11.2 N, respectively.
A new energy harvest system with a hula-hoop transformer, micro-generator and interface energy-harvesting circuit
(2011-06-01)
Chao, Paul C-P
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Shao, C. I.
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Lu, C. X.
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Sung, C. K.
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影像與生醫光電研究所
This study presents a synthesis of a new energy harvest system that consists of a hula-hoop transformer, a micro-generator and an interface energy harvest circuit. The hula-hoop transformer mainly comprises a main mass sprung in one translational direction and a free-moving mass attached at one end of a rod, the other end of which is hinged onto the main mass. The transformer is capable of transforming linear reciprocating motions to rotary ones based on the concepts similar to the hula hoop motions. The transformer is subsequently integrated with a miniaturized rotary generator in size of 10 9 10 9 2 mm 3 and its compact energy harvest circuit chip. The designed generator consists of patterned planar copper coils and a multi-polar hard magnet ring made of NdFeB. The genetic algorithm (GA) is next applied to optimize the critical dimensions of the miniaturized generator. The optimized generator offers 4.5 volt and 7.23 mW in rms at 10,000 rpm. With micro-generator successfully fabricated, a novel energy harvest circuit employing a new dual phase charge pump, power management circuit, a low dropout regulator and battery charger is designed and fabricated via the 0.35 mu m process. This charge pump circuit owns the merit of automatic conversion of low-power AC signals by the micro-generator to DC ones. Experiments were conducted to show the favorable performance of the proposed energy harvest system. This is the first work that invents a motion transformer from ubiquitous reciprocating to rotational motions. In this way, higher-efficient energy conversion via compact-sized rotational electromagnetic generators can be realized as opposed to popular piezoelectric structures.
Dynamic Analysis of a Motion Transformer Mimicking a Hula Hoop
(2011-02-01)
Lu, C. X.
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Wang, C. C.
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Sung, C. K.
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Chao, Paul C. P.
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電機工程學系
Hula-hoop motion refers to the spinning of a ring around a human body; it is made possible by the interactive force between the moving ring and the body. Inspired by the generic concept of hula-hoop motion, this study proposes a novel motion transformer design that consists of a main mass sprung in one translational direction and a free-moving mass attached at one end of a rod, the other end of which is hinged onto the center of the main mass. It is expected that the transformer is capable of transforming linear reciprocating motion into rotational motion. In addition, the transformer could be integrated with coils, magnets, and electric circuits to form a portable energy scavenging device. A thorough dynamic analysis of the proposed transformer system is conducted in this study in order to characterize the relationships between the varied system parameters and the chance of hula-hoop motion occurrence. The governing equations are first derived with Lagrange's method, which is followed by the search for steady-state solutions and the corresponding stability analysis via the homotopy perturbation method and the Floquet theory. Direct numerical simulation is simultaneously performed to verify the correctness of the approximate analysis. In this manner, the feasibility of the proposed design and the occurrence criteria of hula-hoop motion are assessed. [DOI: 10.1115/1.4001839]
DYNAMIC ANALYSIS OF HULA HOOP MOTION AND OPTIMIZED ENERGY HARVEST CIRCUIT
(2014-01-01)
Huang, T. -C.
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Chao, Paul C. -P.
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Chen, W. -D.
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Tsai, C. -H.
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Lu, C. X.
The nonlinear dynamics of hula hoop motion is deciphered in this study by nonlinear dynamic modeling techniques to find solution and stability analysis. This is different from the previous study [1], where a homotopy method is employed. The analysis results are capable of transforming linear reciprocating motion into rotational motion. The dynamic governing equations of the system are first successfully derived by force balance. The non-linear dynamic analysis is next applied to derive approximate, asymptotic solutions. Stabilities associated with all solution are determined by subsequent analysis on the derived asymptotic solutions. In addition, the transformer could be integrated with coils, magnets, and electric circuits to form a portable energy scavenging device. A novel front-end circuit is proposed in this work for harvesting human\'s energy. The situation of human\'s walking and running is simulated by a shaker. And the ac-like energy is processed by the novel energy harvesting circuit, transformed as a DC voltage suitable for devices successfully. The efficiency of the entire circuit is proven up to 60%, and is an input-powered circuit with no standby power. A complete experimental system is also designed and successfully confirm the existence of the stable nonlinear solutions found by analytical and numerical analysis.
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.