Frequency-based nonlinear controller design for regulating systems subjected to time-domain constraints

Glass, John W.; Franchek, Matthew A.

doi:10.1002/(sici)1099-1239(200001)10:1<39::aid-rnc460>3.0.co;2-o

Cited by 8 publications

(6 citation statements)

References 18 publications

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“…If the nonlinear output p(t) is periodic and its derivative is piecewise smooth on the periodic interval 0 ≤ t ≤ 1/ f u [16], p(t) can be expanded to a Fourier series…”

Section: Describing Function Methodsmentioning

confidence: 99%

Frequency-domain based feedback control of flow separation using synthetic jets

Kim

Kerr

Beşkök

et al. 2006

2006 American Control Conference

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This research aims to facilitate feedback control of flow separation using synthetic jets. The effects of synthetic jets on flow separation are assessed via CFD simulations on a rounded backward-facing step. The NARMAX (Nonlinear Auto Regressive Moving Average with eXogenous inputs) system identification method is applied to develop a nonlinear flow model. Low-pass filtering is introduced as an effective method to facilitate a quasi-linear approximation of the nonlinear fluidic system including synthetic jet actuation in the frequency domain. Employing the describing function method, the approximate frequency response of the system is analyzed and implemented for the synthesis of a linear feedback controller. Finally, a PI controller is demonstrated to achieve tracking of a desired pressure with an improvement in the transient response over the open loop system.

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“…If the nonlinear output p(t) is periodic and its derivative is piecewise smooth on the periodic interval 0 ≤ t ≤ 1/ f u [16], p(t) can be expanded to a Fourier series…”

Section: Describing Function Methodsmentioning

confidence: 99%

Frequency-domain based feedback control of flow separation using synthetic jets

Kim

Kerr

Beşkök

et al. 2006

2006 American Control Conference

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“…Let Now the key point is to modify the zero-pole block with nonlinear elements, as it was done in [3]. However, in the present paper the modification is made on the block diagram of a zero-pole or phase lead-lag block.…”

Section: Design Techniquementioning

confidence: 98%

“…1 shows a simple two-window compensator. Another use of the nonlinear elements is presented in [3], where performance specifications were unachievable with a linear controller. After designing a linear block, a lead compensator is extracted and its equation is modified with an odd nonlinear term multiplied by a coefficient.…”

Section: Introductionmentioning

confidence: 99%

A simple hybrid/switching strategy for improving linear controllers

Elso

García-Sanz

2007

2007 Mediterranean Conference on Control &Amp; Automation

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This paper presents a method for improving linear controllers once they have been designed using any linear technique. The controller enhancement is achieved by the introduction of a block which varies two parameters according to the error amplitude. It is also presented a stability condition for the designs, based on previous stability results for switching systems. Both the design method and the stability criterion are easy to use for a control engineer, even not being a specialist on switching control. A classical two-mass-spring benchmark control problem is also presented to illustrate the new technique.

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“…One approach to overcome this limitation is to use nonlinear controllers [4], [10], [11]). Combining switching and QFT was first introduced in [4] to prioritize some specifications over others according to the state of the system at each time.…”

Section: A Qft Design Problemmentioning

confidence: 99%

Design of supervisory based switching QFT controllers for improved closed loop performance

Namaki-Shoushtari

Sedigh

2010

2010 18th Iranian Conference on Electrical Engineering

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In this paper, the problem of supervisory based switching Quantitative Feedback Theory (QFT) control is proposed for the control of highly uncertain plants. According to this strategy, the uncertainty region is divided into smaller regions with a nominal model. It is assumed that a QFT controller exits for robust stability and performance of the individual uncertain sets. The proposed control architecture is made up by these local controllers, which commute among themselves in accordance with the decision of a high level decision maker called the supervisor. The supervisor makes the decision by comparing the candidate local model behavior with the one of the plant and selects the controller corresponding to the best fitted model. A hysteresis switching logic is used to slow down switching for stability reasons. It is shown that this strategy leads to improved closed loop performance, and can also handle the uncertainty sets that can not be tackled by a single QFT robust controller. Simulation results are proposed to show the effectiveness of the proposed methodology.

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Frequency-based nonlinear controller design for regulating systems subjected to time-domain constraints

Cited by 8 publications

References 18 publications

Frequency-domain based feedback control of flow separation using synthetic jets

Frequency-domain based feedback control of flow separation using synthetic jets

A simple hybrid/switching strategy for improving linear controllers

Design of supervisory based switching QFT controllers for improved closed loop performance

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