Browsing by Author "Wu, SD"

Now showing 1 - 13 of 13

Closed-loop fuzzy control of torsional micromirror with multiple electrostatic electrodes
(2002)
Chiou, JC
;
Lin, YC
;
Wu, SD
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Constraint violation stabilization using input-output feedback linearization in multibody dynamic analysis
(1998-03-01)
Chiou, JC
;
Wu, SD
;
電控工程研究所
;
Institute of Electrical and Control Engineering
A constraint violation stabilization technique for solving differential algebraic equations (DAE) of multibody dynamic systems is presented. The technique, based on the input-output feedback linearization, is employed to transform the nonlinear DAE into a set of linear equations. Pin reaching the input-output linear relationship with proven stable zero dynamics, a robust control design is adopted to construct constraint forces that can be used to effectively correct the errors accumulated in the constraint equations during the process of time integration. In the present development. If the pole placement method is used in control design of the resulting linear differential equations, constraint forces based on Baumgarte's constraint violation stabilization technique are recovered. On the other hand, if variable structure control design is adopted, a new method in calculating constraint forces is obtained. Two numerical examples are used to demonstrate the effectiveness of stabilizing the constraint violation by using the proposed technique.
Extraction of substrate parameters for RF MOSFETs based on four-port measurement
(2005-06-01)
Wu, SD
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Huang, GW
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Chen, KM
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Chang, CY
;
Tseng, HC
In this work, a new method for extracting substrate parameters of radio frequency (RF) metal oxide semiconductor field effect transistors (MOSFETs) based on four-port measurement is presented. A T-liked substrate resistance network is used and the values of all components in the cold MOSFETs were extracted directly from the four-port data between 250 MHz and 8.5 GHz. The output admittance Y-22 can be well modeled up to 26.5 GHZ based on the extracted substrate resistances and the other extrinsic capacitances extracted from an active device.
Family of constraint-preserving integrators for solving quaternion equations
(2001-01-01)
Chiou, JC
;
Jan, YR
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Wu, SD
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電控工程研究所
;
Institute of Electrical and Control Engineering
A family of numerical time integrators that exactly preserve the constraint of quaternion equations is developed, The constraint-preserving integrators based on the property of the skew-symmetric matrix and the proposed proven theorems are used to improve the accuracy of updating Euler parameters. The stability and accuracy analysis of the generalized constraint-preserving integrators is also discussed. Furthermore, we demonstrate that the proposed integrators are A-stable integrators that are proven to be useful in calculating angular orientations of kinematic and dynamic systems. A numerical example is used to demonstrate the superiority of the proposed integrators.
Modified Adams-Moulton predictor-corrector method in solving multibody dynamical systems
(2000)
Wu, SD
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Chiou, JC
;
Lin, YC
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電控工程研究所
;
Institute of Electrical and Control Engineering
A modified Adnms-Moulton predictor-corrector method is proposed to solve multibody dynamical systems. The proposed method is obtained by combining an Adams-Bashforth predictor method and an Adams-Moulton corrector method with derived weighting coefficients. With the modification, the accuracy of the proposed method is almost one order of magnitude better than the Adams-Moulton predictor-corrector method with the same step size. Stability limits of the proposed method are also studied. Because the present method has greater stability limits than Adams-Moulton predictor-corrector methods, the proposed method has good robustness during the process of time integration. A crank-slider mechanism is used as an example to investigate the capability of the proposed method in solving multibody dynamic systems.
New constraint stabilization technique for dynamic systems with nonholonomic constraints
(1999-05-01)
Wu, SD
;
Chiou, JC
;
Yang, JY
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電控工程研究所
;
Institute of Electrical and Control Engineering
On the generation of higher order numerical integration methods using lower order Adams-Bashforth and Adams-Moulton methods
(1999-08-15)
Chiou, JC
;
Wu, SD
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, a new explicit numerical integration method is proposed. The proposed method is based on the relationship that m-step Adams-Moulton method is the linear convex, combination of (m - 1)-step Adams-Moulton and m-step Adams-Bashforth methods with a fixed weighting coefficient. By examining the order of accuracy and stability regions, we conclude that the present method is superior to the traditional Adams-Bashforth-Moulton predictor-corrector method. A simple harmonic oscillator problem is used to demonstrate the efficiency of the proposed method. (C) 1999 Elsevier Science B.V. All rights reserved.
Open Newton-Cotes differential methods as multilayer symplectic integrators
(1997-11-01)
Chiou, JC
;
Wu, SD
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交大名義發表
;
電控工程研究所
;
National Chiao Tung University
Open Newton-Cotes differential methods that possess the characteristics of multilayer symplectic structures are shown in this paper. In numerical simulation, volume-preservation plays an important role in solving the Hamiltonian system. In this regard, developing a numerical integrator that preserves the volume in the phase space of a Hamiltonian system is a great challenge to the researchers in this field. Symplectic integrators were proven to be good candidates for volume-preserving integrators (VPIs) in the past ten years. Several one-step (single-stage or multistages) symplectic integrators have been developed based on the symplectic geometric theory. However, multistep VPIs have seldom been investigated by other researchers for the lack of an advanced theory. Recently, Zhu et al. converted open Newton-Cotes differential methods into a multilayer symplectic structure so that multistep VPIs of a Hamiltonian system are obtained. Mainly, their work has concentrated on the issue of achieving both the accuracy and efficiency by solving the quantum systems. But, there exist some unclear aspects in deriving this result in their paper. In this regard, we resolve their problem and provide a different aspect in connecting the relationship between open Newton-Cotes differential methods and symplectic integrators. A numerical example has been carried out to show the effectiveness of the present differential method. (C) 1997 American Institute of Physics. [S0021-9606(97)02234-4].
Reduced reverse narrow channel effect in thin SOI nMOSFETs
(2000-09-01)
Chang, CY
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Chang, SJ
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Chao, TS
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Wu, SD
;
Huang, TY
The effects of narrow channel width on the threshold voltage of deep submicron silicon-on-insulator (SOI) nMOSFETs with LOGOS isolation have been investigated. The reverse narrow channel effect (RNCE) in SOI devices is found to be dependent on the thickness of the active silicon film. A thinner silicon film is found to depict less threshold voltage fall-off. These results can be explained by a reduced oxide/silicon interface area in the transistor width direction, thus the boron segregation due to silicon interstitials with high recombination rate is reduced.
RF MOSFET characterization by four-port measurement
(2005-05-01)
Wu, SD
;
Huang, GW
;
Chen, KM
;
Tseng, HC
;
Hsu, TL
RF MOSFET's are usually measured in common source configuration by a 2-port network analyzer, and the common gate and commen drain S-parameters cannot be directly measured from a conventional 2-port test structure. In this work, a 4-port test structure for on-wafer measurement of RF MOSFET's is proposed. Four-port measurements for RF MOSFET's in different dimensions and the de-embedded procedures are performed up to 20 GHz. The S-parameters of the RF MOSFET in common source (CS), common gate (CG), and common drain (CD) configurations are obtained from a single DUT and one measurement procedure. The dependence of common source S-parameters of the device on substrate bias are also shown.
Robust attitude control of spacecraft using sliding mode control and productive networks
(1997-05-01)
Chiou, JC
;
Hwang, MC
;
Wu, SD
;
Yang, JY
;
交大名義發表
A new robust attitude control design of spacecraft is proposed by combining sliding mode control (SMC) and productive networks (PN). Essentially, the sliding mode control uses discontinuous control action to drive state trajectories toward a specific hyperplane in the state space, and to maintain the state trajectories sliding on the specific hyperplane. This principle provides a guideline to design a robust controller. Productive networks, which are a special type of artificial neural network, are then used to implement reaching and sliding conditions, and tackle the drawbacks of SMC such as chattering and high control gains. Attractive features of the proposed method include a systematic procedure of controller design, a reduction in chattering, robustness against model uncertainties and external disturbances. An inverted pendulum and a spacecraft attitude control problem are given to deomonstrate the effectiveness of the proposed method.
Robust attitude control of spacecraft using sliding mode control and productive networks
(1997-05-01)
Chiou, JC
;
Hwang, MC
;
Wu, SD
;
Yang, JY
;
電控工程研究所
A new robust attitude control design of spacecraft is proposed by combining sliding mode control (SMC) and productive networks (PN). Essentially, the sliding mode control uses discontinuous control action to drive state trajectories toward a specific hyperplane in the state space, and to maintain the state trajectories sliding on the specific hyperplane. This principle provides a guideline to design a robust controller. Productive networks, which are a special type of artificial neural network, are then used to implement reaching and sliding conditions, and tackle the drawbacks of SMC such as chattering and high control gains. Attractive features of the proposed method include a systematic procedure of controller design, a reduction in chattering, robustness against model uncertainties and external disturbances. An inverted pendulum and a spacecraft attitude control problem are given to deomonstrate the effectiveness of the proposed method.
The design and assembly of surface-micromachined optical switch for optical add/drop multiplexer application
(2003-08-01)
Lin, YC
;
Chiou, JC
;
Lin, WT
;
Lin, YJ
;
Wu, SD
An assembly process including: flip-chip bonding, microelectromechanical (MEMS) structure release, and atomic layer deposition (ALD) is proposed to integrate a surface micro-machined optical switch for optical add/drop multiplexer (OADM) applications. In the current optical switch designs, pre-stressed beams were used to pop up the micromirror and an electrode (substrate) under the beams was designed to perform ON/OFF function of the optical switch. In order to achieve desired popped-up angle for precise-optical switching, a flip-chip bonding technique is applied to a mechanical stopper with an accurate joint height that can be used to constrain the movement of the micromirror. A conformal thin layer of dielectric material (Al2O3) coated on the surfaces of device through an ALD coating process is used to improve vertical actuation force, as well as electrical isolation. Experiments indicate that the micromirrors fabricated by the present assembly process can achieve desired angle that meet the requirements of the proposed OADM configuration.