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Lu C.-F.,Chung Chou University of Science and Technology | Hsu C.-H.,National Chung Hsing University | Juang C.-F.,National Chung Hsing University
IEEE Transactions on Power Systems | Year: 2013

This paper proposes an evolutionary fuzzy lead-lag control approach for coordinated control of flexible AC transmission system (FACTS) devices in a multi-machine power system. The FACTS devices used are a thyristor-controlled series capacitor (TCSC) and a static var compensator (SVC), both of which are equipped with a fuzzy lead-lag controller to improve power system dynamic stability. The fuzzy lead-lag controller uses a fuzzy controller (FC) to adaptively determine the parameters of two lead-lag controllers at each control step according to the deviations of generator rotor speeds. This paper proposes an Advanced Continuous Ant Colony Optimization (ACACO) algorithm to optimize all of the free parameters in the FC, which avoids the time-consuming task of parameter selection by human experts. The effectiveness and efficiency of the proposed evolutionary fuzzy lead-lag controller for oscillation damping control is verified through control of a multi-machine power system and comparisons with other lead-lag controllers and various population-based optimization algorithms. © 2012 IEEE.


Chiu M.-C.,Chung Chou University of Science and Technology
Archives of Acoustics | Year: 2011

Recently, there has been research on high frequency dissipative mufflers. However, research on shape optimization of hybrid mufflers that reduce broadband noise within a constrained space is sparse. In this paper, a hybrid muffler composed of a dissipative muffler and a reactive muffler within a constrained space is assessed. Using the eigenvalues and eigenfunctions, a coupling wave equation for the perforated dissipative chamber is simplified into a four-pole matrix form. To efficiently find the optimal shape within a constrained space, a four-pole matrix system used to evaluate the acoustical performance of the sound transmission loss (STL) is evaluated using a genetic algorithm (GA). A numerical case for eliminating a broadband venting noise is also introduced. To verify the reliability of a GA optimization, optimal noise abatements for two pure tones (500 Hz and 800 Hz) are exemplified. Before the GA operation can be carried out, the accuracy of the mathematical models has been checked using experimental data. Results indicate that the maximal STL is precisely located at the desired target tone. The optimal result of case studies for eliminating broadband noise also reveals that the overall sound power level (SWL) of the hybrid muffler can be reduced from 138.9 dB(A) to 84.5 dB(A), which is superior to other mufflers (a one-chamber dissipative and a one-chamber reactive muffler). Consequently, a successful approach used for the optimal design of the hybrid mufflers within a constrained space has been demonstrated.


Chiu M.-C.,Chung Chou University of Science and Technology
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2012

Recently, research on new techniques for dissipative mufflers in dealing with the higher frequencies has been addressed. However, the shape optimization of hybrid mufflers in reducing broadband noise within a constrained space as well as a pressure-drop limit which are both concerned with the necessity of operation and system venting in practical engineering work was rarely tackled. Therefore, this study will not only analyze the sound transmission loss (STL) of a space-constrained multichamber hybrid muffler but also optimize the best design shape under a specified pressure drop. In this paper, the generalized decoupling technique and plane wave theory used to solve the coupled acoustical problem of perforated mufflers with/without sound absorbing material are presented. The four-pole system matrix used to evaluate acoustic performance is also introduced in conjunction with a genetic algorithm (GA). A numerical case for eliminating a broadband venting noise emitted from a pressure relief valve using four kinds of hybrid mufflers is also introduced. To verify the reliability of the GA optimization, optimal noise abatement for a pure tone (1000 Hz) is exemplified. Before the GA operation can be carried out, the accuracy of the mathematical models need to be checked using the experimental data. The optimal result in eliminating broadband noise reveals that the overall noise reductions with respect to various mufflers under a maximal allowable pressure drop of 100 Pa can achieve 62.6, 54.8, 32.3 and 87.8 dB. Consequently, the approach used for the optimal design of the multichamber hybrid mufflers under space and back pressure constrained conditions is indeed easy and quite effective. © 2012 American Society of Mechanical Engineers.


Hwang H.-E.,Chung Chou University of Science and Technology
Optics Communications | Year: 2012

A novel technique, based on a modified Gerchberg-Saxton algorithm (MGSA) in the Fresnel-transform (FrT) domain, is proposed to encode a color image into three phase-only functions (POFs) for three separated channels: red (R), green (G), and blue (B). The decomposed three RBG channels can avoid the interference of crosstalks efficiently. In proposed decryption process, a color image can be promptly reconstructed by summing of the three decrypted RGB images after the created three POFs which are decrypted one by one. In this paper, all the created three POFs and the system parameters of FrT can be used as the keys for increasing security that are also demonstrated. The computer application simulations to the partial color encryption and decryption are given to validate the feasibility of the proposed scheme. © 2011 Elsevier B.V. All rights reserved.


Yeh F.-K.,Chung Chou University of Science and Technology
Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering | Year: 2013

This study addresses a sliding-mode-based contour-following controller design for guidance and autopilot systems of launch vehicles with highly maneuverable actuators, mainly consisting of the thrust vector control and side jet systems, to perform the trajectory-tracking task given a predetermined trajectory. In particular, the trajectory is pre-designed by the method of calculus of variations with focus on maximizing the final velocity transferring to the orbit to obtain the optimal trajectory for a launch vehicle throughout the whole course. Chiefly, an integrated guidance/autopilot controller is designed to achieve the main goal of robust tracking issues for launch vehicles in real time such that the relative motion between a vehicle and the predetermined trajectory is minimized. As for the attitude control, an autopilot system is designed not only to stabilize the attitude of the launch vehicle but also to realize the guidance law of the translational motion control. In order to establish a complete system model, besides the motion dynamics of launch vehicles, we also take into account several influential factors such as the propellant effort of a movable nozzle thrust vector control and side jet systems, aerodynamic influence, the Earth's gravitational field, and wind gusts/shears. The overall stability of the integrated guidance/autopilot system is assured via rigorous analysis by Lyapunov stability theory, and its corresponding performance is verified by numerical simulations. © IMechE 2012.


Chiu M.-C.,Chung Chou University of Science and Technology
Journal of Low Frequency Noise Vibration and Active Control | Year: 2011

Although research in finding optimal muffler shapes for low-frequencies noise using reactive mufflers has already been addressed, research into shape optimization of hybrid mufflers that reduce broadband noise within a constrained pressure-drop backpressure is lacking. Therefore, the shape optimization of four kinds of hybrid mufflers using simulated annealing (SA) in conjunction with the generalized decoupling technique and plane wave theory are presented. Here, a numerical case in eliminating nitrogen venting noise is introduced. The reliability of the SA optimization is also verified using the optimization of muffler A for a pure tone. Moreover, the accuracy of the mathematical models is acceptable with minor deviations between the theoretical and experimental data. Results reveal that the higher backpressure limit will result in a higher acoustical performance. Consequently, the acoustical performance for a hybrid muffler equipped with multiple reactive chambers and one dissipative chamber is superior to that of reactive mufflers.


Chiu M.-C.,Chung Chou University of Science and Technology
Archives of Acoustics | Year: 2012

Noise control is essential in an enclosed machine room where the noise level has to comply with the occupational safety and health act. In order to overcome a pure tone noise with a high peak value that is harmful to human hearing, a traditional reactive muffler has been used. However, the traditional method for designing a reactive muffler has proven to be time-consuming and insufficient. In order to efficiently reduce the peak noise level, interest in shape optimization of a Helmholtz muffler is coming to the forefront. Helmholtz mufflers that deal with a pure tone have been adequately researched. However, the shape optimization of multi-chamber Helmholtz mufflers that deal with a broadband noise hybridized with multiple tones within a constrained space has been mostly ignored. Therefore, this study analyzes the sound transmission loss (STL) and the best optimized design for a hybrid Helmholtz muffler under a space- constrained situation. On the basis of the plane wave theory, the four-pole system matrix used to evaluate the acoustic performance of a multi-tone hybrid Helmholtz muffler is presented. Two numerical cases for eliminating one/two tone noises emitted from a machine room using six kinds of mufflers (muffler A∼F) is also introduced. To find the best acoustical performance of a space-constrained muffler, a numerical assessment using a simulated annealing (SA) method is adopted. Before the SA operation can be carried out, the accuracy of the mathematical model has been checked using the experimental data. Eliminating a broadband noise hybridized with a pure tone (130 Hz) in Case I reveals that muffler C composed of a one- chamber Helmholtz Resonator and a one-chamber dissipative element has a noise reduction of 54.9 (dB). Moreover, as indicated in Case II, muffler F, a two-chamber Helmholtz Resonator and a one-chamber dissipative element, has a noise reduction of 69.7 (dB). Obviously, the peak values of the pure tones in Case I and Case II are efficiently reduced after the muffler is added. Consequently, a successful approach in eliminating a broadband noise hybridized with multiple tones using optimally shaped hybrid Helmholtz mufflers and a simulated annealing method within a constrained space is demonstrated. Copyright © 2012 by PAN - IPPT.


Yeh F.-K.,Chung Chou University of Science and Technology
IET Control Theory and Applications | Year: 2012

This work addresses an attitude controller design using a fuzzy sliding-mode controller, which is mainly composed of the sliding-mode controller and the fuzzy inference mechanism, for a mini-unmanned aerial vehicle (mini-UAV) with propellers, to follow the predetermined trajectory. In this study, a fuzzy sliding-mode controller with a sliding surface vector is proposed, such that a simple fuzzy inference mechanism is adopted with centre of membership functions to estimate the upper bound of lumped uncertainty. Accordingly, the attitude trajectory tracking control using the proposed control strategy is illustrated while a mini-UAV is flying. Finally, the authors use the Lyapunov stability theory to achieve the stability analysis of the overall attitude tracking system degraded by white noise interference. Extensive simulation results are obtained to validate the effectiveness of the fuzzy sliding-mode controller. © 2012 The Institution of Engineering and Technology.


Yeh F.-K.,Chung Chou University of Science and Technology
IET Control Theory and Applications | Year: 2012

This approach addresses an adaptive-sliding-mode guidance law for missiles equipped with thrust vector control and divert control system, for the task of intercepting of a theatre ballistic missile with manoeuvring acceleration. The aim of the present study is to achieve a bounded target interception under the three degrees of freedom (DOF) control and the zero-effort-miss phase to improve the intercepting accuracy of the missile by narrowing the distance between the intercepting missile and the target missile to within effective range for triggering the missile's explosion. Considering the external disturbances and the variation in the missile's mass, the 3 DOF adaptive-sliding-mode guidance law is designed using adaptive control and sliding-mode control to minimise the distance between the centre of the intercepting missile and that of the target missile asymptotically. Also, the overall system stability is verified using the Lyapunov stability theory. Furthermore, successful simulation results are conducted to validate the effectiveness of the proposed adaptive-sliding-mode guidance law. © 2012 The Institution of Engineering and Technology.


Chiu M.-C.,Chung Chou University of Science and Technology
Journal of Sound and Vibration | Year: 2013

A broadband noise hybridized with pure tones often occurs in practical engineering work. However, assessments of a muffler's optimal shape design that would simultaneously overcome a broadband noise hybridized with multiple tones within a constrained space were rarely addressed. In order to promote the best acoustical performance in mufflers, five kinds of the hybrid mufflers composed of a reactive unit, a dissipative unit, and Helmholtz resonator (HR) units will be proposed. Moreover, to strengthen the noise elimination at the pure tone, mufflers having parallel multiple-sectioned HRs or having multiple HR connections in series (muffler D and muffler E) will be also presented in the noise abatement. On the basis of the plane wave theory, the four-pole system matrix used to evaluate the acoustic performance of a multi-tone hybrid Helmholtz muffler will be presented. A numerical case for eliminating broadband noise hybridized with a pure tone emitted from a machine room using five kinds of mufflers (muffler A-E) will also be introduced. To find the best acoustical performance of a space-constrained muffler, a numerical assessment using a simulated annealing (SA) method is adopted. To verify the availability of the SA optimization, a numerical optimization of muffler A at a pure tone (280 Hz) is exemplified. Before the SA operation can be carried out, the accuracy of the mathematical model will be checked using the experimental data. The influences of the sound transmission loss (STL) with respect to N1-array HR and the STL with respect to one-array HR sectioned in N2 divisions have also been assessed. Also, the influence of the STL with respect to the design parameters such as the ratio of d1/d2, the diameter of the perforated hole (dH), the porosity (p%) of the perforated plate, and the outer diameter (d2) of the dissipative unit has been analyzed. Consequently, a successful approach in eliminating a broadband noise hybridized with a pure tone using optimally shaped hybrid mufflers and a simulated annealing method within a constrained space has been demonstrated. © 2013 Elsevier Ltd.

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