Browsing by Author "Sung, Cheng-Kuo"

Now showing 1 - 8 of 8

A novel method for fabrication of self-aligned double microlens arrays
(2007-04-15)
Ho, Jeng-Rong
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Shih, Teng-Kai
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Cheng, J. W. John
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Sung, Cheng-Kuo
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Chen, Chia-Fu
Based on the excimer laser microdrilling and the spin coating scheme, a new fabrication method of polymeric, double microlens arrays on a thin plastic pedestal sheet is proposed in this study. On each through hole on the pedestal sheet, a double microlens pair, consisting of two microlenses with different parabolic surfaces, is sited. The two microlenses of each pair are located respectively on both ends of the through hole and arranged surface to surface and automatically share a common lens principal axis. The fabricated microlens arrays are made of PMMA that are formed on a PMMA pedestal sheet with thickness of 100 mu m. The diameter and height for the microlens on one layer are of 150 mu m and 28 mu m, respectively, and they are correspondingly of 130 mu m and 24 mu m on the other layer. Experimental results demonstrate that the double microlens arrays have a better focusing property than the single-layer mircolens array. Simulation results indicate that, simply by changing the thickness of the pedestal sheet, the present fabricated double microlens arrays can serve the purposes for light collimating and diffusing. Due to its inherent simplicity in fabrication, the present method has high flexibility for making double microlens arrays with different lens configurations and various lens refractive indices. The facts that precise alignment and all processing steps are performed in ambient and at low temperature render the proposed approach a potential low-cost method for fabrication of double microlens arrays. (c) 2006 Elsevier B.V. All rights reserved.
Landing posture control of a generalized 5-RDOF twin-body system via methods of input-output linearization and PD control
(2007)
Yang, Yi-Ling
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Yang, Cheng-Cheng
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Chao, Paul C. -P.
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Sung, Cheng-Kuo
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電控工程研究所
This study is dedicated to achieve landing posture control of a generalized 5-Rotadonal-DOF (5-RDOF) twin-body system using methods of PD control and input-output linearization. The 5-RDOF twin-body system considered is in fact a simplified model of a cellular phone. A successfully designed landing posture control scheme is expected to prevent structural damage of the cellular phone. To this end, dynamic equations of motion for the 5-RDOF twin-body system are built based on the Lagrange-Euler formulation. To simplify the modeling, the input torques associated with 2-RDOF joint have been decoupled by defining relative rotational angles of the joint as state variables. There are two controllers applied to achieve the final landing posture control: (1) PD controller and (2) input-output linearization with computed torques. Finally, the controller performance is validated by MATLAB simulations. The results show that the design controller is capable of performing landing control, and the relations between dynamics responses and control variables are discussed.
Landing Posture Control via Trajectory Planning for a Generalized Twin-body System
(2009)
Yang, Yi-Ling
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Chao, Paul C. -P.
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Sung, Cheng-Kuo
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電控工程研究所
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Institute of Electrical and Control Engineering
For the purpose of preventing a free-failing object from damage, this study is devoted to the landing posture control via trajectory planning for a generalized twin-body system by employing the methods of PD and sliding control. The system discussed herein is the simplified model of a free-failing cellular phone with two rotational DOFs. In this paper, the governing equations of the system are first established based on the Lagrange-Euler formulation. Then, PD and sliding controllers are designed to achieve the desired landing posture. In addition, the trajectory planning is adopted to reduce the input energy. The performance of the controller is validated by MATLAB simulations, and the relations between input energy, trajectory-function, and falling height are discussed.
Nonplanar modeling and experimental validation of a spindle-disk system equipped with an automatic balancer system in optical disk drives
(2007-05-01)
Chao, Paul C. -P.
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Sung, Cheng-Kuo
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Wu, Szu-Tuo
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Huang, Jeng-Sheng
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電控工程研究所
Non-planar dynamic modeling and experimental validation of a spindle-disk system equipped with an automatic ball-type balancer system (ABS) in optical disc drives are performed in this study. Recent studies about planar dynamic modeling and analysis have shown the capability of the ABS in spindle-disk assembly via counteracting the inherent imbalance. To extend the analysis to be practical, non-planar dynamic modeling are conducted in this study to re-affirm the pre-claimed capability of the ABS system, along with experiments being designed and conducted to validate the theoretical findings. Euler angles are first utilized to formulate potential and kinetic energies, which is followed by the application of Lagrange's equation to derive governing equations of motion. Numerical simulations are next carried out to explore dynamic characteristics of the system. It is found that the levels of residual runout (radial vibration), as compared to those without the ABS, are significantly reduced, while the tilting angle of the rotating assembly can be kept small with the ABS installed below the inherent imbalance of the spindle-disk system. Experimental study is also conducted, and successfully validates the aforementioned theoretical findings. It is suggested that the users of the ABS need to cautiously operate the spindle motor out of the speeds close to the resonances associated with various degrees of freedom. In this way, the ABS could hold the expected capability of reducing vibration in all important directions, most importantly in radial directions.
Optimal Control of an Under-Actuated System for Landing With Desired Postures
(2011-03-01)
Yang, Eileen Chih-Ying
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Chao, Paul C. -P.
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Sung, Cheng-Kuo
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電控工程研究所
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Institute of Electrical and Control Engineering
Control over landing posture can effectively prevent structural damage when a portable device is accidentally dropped. Given size and cost constraints, the number of actuators should be limited. This paper presents an optimal posture control method that allows an under-actuated system to land with the desired posture. A simplified model of a portable computer/telephone is considered, comprising two rigid bodies and an active joint. The objective is to minimize the input torque produced by the actuator to achieve the desired posture. A two-point boundary value problem is formulated; i.e., the initial and final angular positions and velocities are predetermined, and the inequality constraints are established on the basis of the capacity of the actuator and acceptable level of state variables. In the numerical analysis, the backward-sweep algorithm is applied to determine the appropriate Lagrange multiplier, and the falling dynamics are explored using MATLAB. The optimal controller design is presented, together with simulation results confirming that the system is capable of performing landing posture control with minimum input torque.
Sliding-mode control of a twin-body system with 2-relative-RDOF to achieve desired landing postures
(2007)
Yang, Yi-Ling
;
Yang, Chen Cheng
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Chao, Paul C. -P.
;
Sung, Cheng-Kuo
;
電控工程研究所
This study is dedicated to accomplish landing posture control of a twin-body system with 2-relative rotation degree of freedom (RDOF) using method of sliding control. The twin-body system is simplified model of a cellular phone with two relative RDOF, the inclination between two bodies and rotation through self-axis. The objective of the research is controlling the landing posture without structural damage. First, the equations governing the dynamics of the twin-body system are essential based on the Lagrange-Euler formulation. The damping uncertainty caused by the actuators with bearing would be considered, and the robust controller is designed based on the sliding control and applied to achieve the control object. Finally the controller performance is validated by MATLAB simulations. The results shown that the designed controller is capable of performing lading control, and the relations between dynamics responses and control variables are discussed.
Superhydrophobic, antiadhesive, and antireflective surfaces mediated by hybrid biomimetic salvinia leaf with moth-eye structures
(2014-08-01)
Yang, Cho-Yun
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Tsai, Yu-Lin
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Yang, Cho-Yu
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Sung, Cheng-Kuo
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Yu, Peichen
In this paper, we successfully demonstrate multifunctional surfaces based on scaffolding biomimetic structures, namely, hybrid salvinia leaves with moth-eye structures (HSMSs). The novel fabrication process employs scalable polystyrene nanosphere lithography and a lift-off process. Systematic characterizations show the biomimetic HSMS exhibiting superhydrophobic, self-cleaning, antiadhesive, and antireflective properties. Furthermore, the resulting surface tension gradient (known as the Marangoni effect) leads to a superior air retention characteristic in the HSMS under water droplet impact, compared with the traditional hybrid lotus leaf with a moth-eye structure (HLMS). Such results and learnings pave the way towards the attainment and mass deployment of dielectric surfaces with multiple functionalities for versatile biological and optoelectronic applications. (C) 2014 The Japan Society of Applied Physics
Superhydrophobic, antiadhesive, and antireflective surfaces mediated by hybrid biomimetic salvinia leaf with moth-eye structures (vol 7, 087001, 2014)
(2015-06-01)
Yang, Cho-Yun
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Tsai, Yu-Lin
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Yang, Cho-Yu
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Sung, Cheng-Kuo
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Yu, Peichen