Browsing by Author "Shen, Chien-Yu"

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Design and implementation of a sliding-mode controller and a high-gain observer for output tracking of a three-axis pickup
(2007-04-15)
Chao, Paul C. -P.
;
Shen, Chien-Yu
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電控工程研究所
;
Institute of Electrical and Control Engineering
A novel decoupling actuation scheme applied to a new three-axis four-wire optical pickup is synthesized in this study based on theories of sliding-mode control and high-gain observer. The three-axis pickup owns the capability to move the lens holder in three directions of focusing, tracking and tilting. This capability is required particularly for higher data-density optical disks to annihilate the non-zero lens tilting. To achieve control design, Lagrange's equations are first employed to derive equations of motion for the lens holder. A sliding-mode controller is then designed to perform dynamic decoupling and nonlinearity cancellation with the aims of precision tracking, focusing and no tilting. A full-order high-gain observer is next forged to estimate the velocities of the moving lens holder in order to provide low-noised feedback velocity signals for the designed sliding-mode controller. Simulations are carried out to choose appropriate parameter values of the designed controller and observer. Finally, experiments are conducted to validate the effectiveness of the controller for annihilating lens tilting and the capability of the observer for reducing the effects of digital noises on pickup positionings. (c) 2006 Elsevier B.V. All rights reserved.
Dynamic modeling and experimental verification of a piezoelectric part feeder in a structure with parallel bimorph beams
(2007-06-01)
Chao, Paul C. -P.
;
Shen, Chien-Yu
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The study is aimed to perform dynamic modeling of a part feeder powered by piezoelectric actuation. This part feeder consists mainly of a horizontal platform vibrated by a pair of parallel piezoelectric bimorph beams. Owing to intermittent impacts with the platform, the transported part on the platform is able to march forward from one end to another. Dynamic modeling of the feeder is accomplished by essentially using the Rayleigh-Ritz decomposition method. The process of modeling first incorporates material properties and constitutive equations of the piezoelectric materials, and then captures the complex dynamics of the parallel-beam piezo-feeder by three low-order assumed-modes in the transverse direction of the vibrating beams. Applying Lagrange's equations on the kinetic and strain energies formulated in terms of generalized coordinates associated with the first three modes, the system dynamics is then represented by three coupled discrete equations of motion. Based on these equations, motions of the platform can be obtained. With platform motion in hand, the intermittent impacts between the parts and the platform are modeled, rendering the marching speed of the part. Numerical simulations are conducted along with the experiments. The closeness found between the theoretical predicted transporting speed of the part and the experimental counterparts verify the effectiveness of the models established. (C) 2007 Elsevier B.V. All rights reserved.
Novel lens design and experimental verification for high efficiency direct lype backlight module of LCD-TVs
(2007)
Chiu, Chi-Wei
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Shen, Chien-Yu
;
Chao, Paul C. -P.
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Sensorless Tilt Compensation for a Three-Axis Optical Pickup Using a Sliding-Mode Controller Equipped With a Sliding-Mode Observer
(2009-03-01)
Chao, Paul C. -P.
;
Shen, Chien-Yu
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A sliding-mode controller equipped with a sliding-mode observer is synthesized and applied to a novel three-axis four-wire optical pickup for the purpose of sensorless tilt compensation. The three-axis pickup owns the capability to move the lens holder in three directions of focusing, tracking and tilting, which is required particularly for higher data-density optical disks and precision measuring instruments to annihilate nonzero lens tiltings. To achieve the sensorless compensation, Lagrange's equations are first employed to derive equations of motion for the lens holder. A sliding-mode controller is then designed to perform dynamic decoupling and forge control efforts toward the goals of precision tracking, focusing, and zero tilting. Along with the controller, a sliding-mode observer is designed to perform the online tilt estimation of the lens holder. This estimated tilt allows the previously designed sliding-mode controller to be implemented in most existing commercial pickups without additional photodiodes to detect the tilting motion of the lens holder. A full-order high-gain observer is next forged to estimate the moving velocities of the lens holder in order to provide low-noised feedback velocity signals for the designed sliding-mode controller. Simulations are carried out to choose appropriate controller and observer gains. Finally, experiments are conducted to validate the effectiveness of the controller for annihilating lens tilting And the capability of the tilt observer for performing sensorless tilt compensation.