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William C Messner - One of the best experts on this subject based on the ideXlab platform.
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Advanced Manual System Identification Using Lead and Lag Compensators With Complex Poles and Zeros
Volume 1: Advances in Control Design Methods Nonlinear and Optimal Control Robotics and Wind Energy Systems; Aerospace Applications; Assistive and Reh, 2016Co-Authors: Piers M. Echols-jones, Maxim Dokukin, Igor M. Sokolov, William C MessnerAbstract:Automated methods for deriving dynamic models from frequency response data of high-order dynamics systems are the default choice of most engineers. However, these methods themselves often require manual tuning of weighting parameters, a priori selection of system order, and even by hand removal of extraneous dynamics. On the other hand, manually matching complicated features in the Bode Plot of the frequency response of high-order system is difficult with conventional first and second order numerators and denominators. In this papers we present a manual technique for systematically creating a dynamic model from Bode Plots of frequency response data with complicated features. We apply the method to identifying dynamics of a piezoelectric stage holding the sample of an atomic force microscope (AFM). We show the manual method works better than the tfest command of Matlab™ for this example system.
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controller design for nonlinear multi input multi output systems using the contoured robust controller Bode Plot
Volume 3: Nonlinear Estimation and Control; Optimization and Optimal Control; Piezoelectric Actuation and Nanoscale Control; Robotics and Manipulators, 2013Co-Authors: J. D. Taylor, William C MessnerAbstract:In this paper, a novel approach to controller design for non-linear multi–input/multi–output (MIMO) systems is presented based on the Contoured Robust Controller Bode (CRCBode) Plot. CRCBode Plots show level–sets of a robust metric and identify certain “forbidden regions” on the controller Bode magnitude and phase Plots such that intersections of the controller frequency response with these forbidden regions indicate that a robust stability and performance criterion is violated. Nonlinear system dynamics are included as a structured uncertainty set consisting of linearizations about several operating points. To demonstrate this approach, we design a controller for a MIMO high–speed, low–tension magnetic tape drive memory system. A preliminary approximate inverse step is described, followed by several loop–shaping design iterations to eliminate all intersections with the forbidden regions on the CRCBode diagrams. Finally, the CRCBode compensator is compared to one generated using an automated H∞ synthesis algorithm.Copyright © 2013 by ASME
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Modified Bode Plots for Robust Performance in SISO Systems With Structured and Unstructured Uncertainties
IEEE Transactions on Control Systems Technology, 2012Co-Authors: Takenori Atsumi, William C MessnerAbstract:We have developed a loop-shaping methodology for robust control design in single-input single-output (SISO) systems with structured and unstructured uncertainties. This design method employs visualization tools that are modifications of the classical Bode Plot. Using the proposed method control engineers can easily consider the effects of the structured and unstructured uncertainties without the need for transfer-function models of the plant, the sensitivity function performance, or the uncertainty. The method simultaneously can avoid excessive conservativeness and excessively high order controllers while improving controller performance and robustness. We show utility of the proposed method by applying it to a head-positioning control system in a hard disk drive.
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Nonlinear modeling of butterfly valves and flow rate control using the Circle Criterion Bode Plot
Proceedings of the 2010 American Control Conference, 2010Co-Authors: J. D. Taylor, Bruno Sinopoli, William C MessnerAbstract:Butterfly valves are widely used control components in piping systems. This paper derives the nonlinear mathematical relationship between flow rate, pressure difference, and valve angle in a butterfly valve. We use the Circle Criterion Bode Plot and loop shaping to design a flow rate controller in a motor-gearbox-butterfly valve system. The design employs a complex proportional-integral-lead (CPIL) compensator, and we show the benefit of using a damping ratio less than unity. Finally, we demonstrate the effectiveness of the design through simulation.
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Modified Bode Plots for Head-Positioning Control in Hard Disk Drives with Structured and Unstructured Uncertainties
IFAC Proceedings Volumes, 2010Co-Authors: Takenori Atsumi, William C MessnerAbstract:Abstract This paper presents a loop-shaping method for robust control design that can account for structured uncertainties using modifications of the classical Bode Plot. By using this method, the robust performance criterion is explicitly translated into allowable and forbidden regions on Bode Plot of a compensated SISO system. There is no need for transfer function-based models of the plant, the sensitivity function performance, or the uncertainty. As a result, the designed controllers are able to avoid excessive conservativeness that may lead to high-order controllers while improving the control performance. This paper shows utility of the proposed method by applying it to a head-positioning control system in a hard disk drive.
Bei Gou - One of the best experts on this subject based on the ideXlab platform.
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A PEM fuel cell temperature controller design using a thermal equivalent circuit model
International Journal of Power and Energy Conversion, 2012Co-Authors: Bei GouAbstract:In order to control a temperature in the fuel cell system, a thermal equivalent circuit model for PEM fuel cells and its control algorithms are presented. By defining temperature as a state, the energy balance model can be established so that feedback control algorithm can be directly employed. The details of the design of the thermal equivalent circuit model and its control scheme are provided in the paper. The proposed thermal equivalent circuit model and its control design were analysed through Bode Plots. Based on the Bode Plot results, the proposed thermal circuit model for PEM fuel cells is applied to design an appropriate temperature controller.
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ISCAS - A thermal equivalent circuit for PEM fuel cell temperature control design
2008 IEEE International Symposium on Circuits and Systems, 2008Co-Authors: Bei GouAbstract:A thermal equivalent circuit is presented in this paper for polymer electrolyte membrane (PEM) fuel cells. In order to control a temperature in the fuel cell system, a thermal equivalent circuit model for polymer electrolyte membrane (PEM) fuel cells and its control algorithms are presented. By defining temperature as a state, the energy balance can be established so that feedback control algorithm can be directly utilized. The details of the design of the thermal equivalent circuit model and its control scheme are provided in the paper. The proposed thermal equivalent circuit model was analyzed through Bode Plots. With the help of Bode Plot results, the proposed thermal circuit model for PEM fuel cells can be used in designing an appropriate controller.
J. D. Taylor - One of the best experts on this subject based on the ideXlab platform.
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Controller Design for Nonlinear Multi-Input/Multi-Output Systems Using the Contoured Robust Controller Bode Plot
Volume 3: Nonlinear Estimation and Control; Optimization and Optimal Control; Piezoelectric Actuation and Nanoscale Control; Robotics and Manipulators, 2013Co-Authors: J. D. Taylor, William MessnerAbstract:In this paper, a novel approach to controller design for non-linear multi–input/multi–output (MIMO) systems is presented based on the Contoured Robust Controller Bode (CRCBode) Plot. CRCBode Plots show level–sets of a robust metric and identify certain “forbidden regions” on the controller Bode magnitude and phase Plots such that intersections of the controller frequency response with these forbidden regions indicate that a robust stability and performance criterion is violated. Nonlinear system dynamics are included as a structured uncertainty set consisting of linearizations about several operating points. To demonstrate this approach, we design a controller for a MIMO high–speed, low–tension magnetic tape drive memory system. A preliminary approximate inverse step is described, followed by several loop–shaping design iterations to eliminate all intersections with the forbidden regions on the CRCBode diagrams. Finally, the CRCBode compensator is compared to one generated using an automated H∞ synthesis algorithm.Copyright © 2013 by ASME
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controller design for nonlinear multi input multi output systems using the contoured robust controller Bode Plot
Volume 3: Nonlinear Estimation and Control; Optimization and Optimal Control; Piezoelectric Actuation and Nanoscale Control; Robotics and Manipulators, 2013Co-Authors: J. D. Taylor, William C MessnerAbstract:In this paper, a novel approach to controller design for non-linear multi–input/multi–output (MIMO) systems is presented based on the Contoured Robust Controller Bode (CRCBode) Plot. CRCBode Plots show level–sets of a robust metric and identify certain “forbidden regions” on the controller Bode magnitude and phase Plots such that intersections of the controller frequency response with these forbidden regions indicate that a robust stability and performance criterion is violated. Nonlinear system dynamics are included as a structured uncertainty set consisting of linearizations about several operating points. To demonstrate this approach, we design a controller for a MIMO high–speed, low–tension magnetic tape drive memory system. A preliminary approximate inverse step is described, followed by several loop–shaping design iterations to eliminate all intersections with the forbidden regions on the CRCBode diagrams. Finally, the CRCBode compensator is compared to one generated using an automated H∞ synthesis algorithm.Copyright © 2013 by ASME
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Controller design for nonlinear systems using the Contoured Robust Controller Bode Plot
International Journal of Robust and Nonlinear Control, 2013Co-Authors: J. D. Taylor, William MessnerAbstract:SUMMARY In this paper, we develop the Contoured Robust Controller Bode (CRCBode) Plot and demonstrate its use in the design of robust controllers for nonlinear single-input single-output (SISO) systems. The CRCBode Plot shows contours (level sets) of a robust performance quantity on the Bode magnitude and phase Plots of the controller. An iterative frequency domain loop-shaping design approach is employed to eliminate all intersections of the controller frequency response with certain ‘forbidden regions,’ indicating that a standard SISO robust stability and performance criterion is satisfied. Nonlinearities are accounted for by avoiding the maximum forbidden regions over a structured uncertainty set consisting of linearizations of the system dynamics about several operating points. We demonstrate this technique by designing and experimentally verifying a flow-rate controller for a butterfly-valve based liquid cooling system, which is robust to valve nonlinearities and flow disturbances. Finally, we compare this compensator with one generated using an automated H ∞ synthesis algorithm and discuss the advantages of the CRCBode approach. Copyright © 2013 John Wiley & Sons, Ltd.
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Nonlinear modeling of butterfly valves and flow rate control using the Circle Criterion Bode Plot
Proceedings of the 2010 American Control Conference, 2010Co-Authors: J. D. Taylor, Bruno Sinopoli, William C MessnerAbstract:Butterfly valves are widely used control components in piping systems. This paper derives the nonlinear mathematical relationship between flow rate, pressure difference, and valve angle in a butterfly valve. We use the Circle Criterion Bode Plot and loop shaping to design a flow rate controller in a motor-gearbox-butterfly valve system. The design employs a complex proportional-integral-lead (CPIL) compensator, and we show the benefit of using a damping ratio less than unity. Finally, we demonstrate the effectiveness of the design through simulation.
William Messner - One of the best experts on this subject based on the ideXlab platform.
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Controller Design for Nonlinear Multi-Input/Multi-Output Systems Using the Contoured Robust Controller Bode Plot
Volume 3: Nonlinear Estimation and Control; Optimization and Optimal Control; Piezoelectric Actuation and Nanoscale Control; Robotics and Manipulators, 2013Co-Authors: J. D. Taylor, William MessnerAbstract:In this paper, a novel approach to controller design for non-linear multi–input/multi–output (MIMO) systems is presented based on the Contoured Robust Controller Bode (CRCBode) Plot. CRCBode Plots show level–sets of a robust metric and identify certain “forbidden regions” on the controller Bode magnitude and phase Plots such that intersections of the controller frequency response with these forbidden regions indicate that a robust stability and performance criterion is violated. Nonlinear system dynamics are included as a structured uncertainty set consisting of linearizations about several operating points. To demonstrate this approach, we design a controller for a MIMO high–speed, low–tension magnetic tape drive memory system. A preliminary approximate inverse step is described, followed by several loop–shaping design iterations to eliminate all intersections with the forbidden regions on the CRCBode diagrams. Finally, the CRCBode compensator is compared to one generated using an automated H∞ synthesis algorithm.Copyright © 2013 by ASME
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Controller design for nonlinear systems using the Contoured Robust Controller Bode Plot
International Journal of Robust and Nonlinear Control, 2013Co-Authors: J. D. Taylor, William MessnerAbstract:SUMMARY In this paper, we develop the Contoured Robust Controller Bode (CRCBode) Plot and demonstrate its use in the design of robust controllers for nonlinear single-input single-output (SISO) systems. The CRCBode Plot shows contours (level sets) of a robust performance quantity on the Bode magnitude and phase Plots of the controller. An iterative frequency domain loop-shaping design approach is employed to eliminate all intersections of the controller frequency response with certain ‘forbidden regions,’ indicating that a standard SISO robust stability and performance criterion is satisfied. Nonlinearities are accounted for by avoiding the maximum forbidden regions over a structured uncertainty set consisting of linearizations of the system dynamics about several operating points. We demonstrate this technique by designing and experimentally verifying a flow-rate controller for a butterfly-valve based liquid cooling system, which is robust to valve nonlinearities and flow disturbances. Finally, we compare this compensator with one generated using an automated H ∞ synthesis algorithm and discuss the advantages of the CRCBode approach. Copyright © 2013 John Wiley & Sons, Ltd.
Mohammad Saleh Tavazoei - One of the best experts on this subject based on the ideXlab platform.
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Fractional order control of thermal systems: achievability of frequency-domain requirements
Nonlinear Dynamics, 2015Co-Authors: Vahid Badri, Mohammad Saleh TavazoeiAbstract:Fractional order models have been widely used in modeling and identification of thermal systems. General model in this category is considered as the model of thermal systems in this paper, and a fractional order controller is proposed for controlling such systems. The proposed controller is a generalization for the traditional PI controllers. The parameters of this controller can be obtained by using a recently introduced tuning method which can simultaneously ensure the following three requirements: desired phase margin, desired gain crossover frequency, and flatness of the phase Bode Plot at this frequency. In this paper, it is found whether simultaneously achieving the mentioned frequency-domain requirements will be possible in the control of the considered thermal systems. Numerical examples are presented to show the usefulness of the obtained results.
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On tuning FO[PI] controllers for FOPDT processes
Electronics Letters, 2013Co-Authors: Vahid Badri, Mohammad Saleh TavazoeiAbstract:A method recently proposed for tuning fractional order [proportional integral] (FO[PI]) controllers is investigated. This tuning method, when applied in control of first-order plus dead time (FOPDT) processes, can ensure the desired phase margin, the desired gain crossover frequency and the flatness of the phase Bode Plot at such a frequency. The necessary and sufficient condition for the applicability of the aforementioned tuning method is derived. Also, it is shown that this condition can be used in obtaining the achievable performance region of the tuning method in the gain crossover frequency-phase margin plane.
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On tuning fractional order [proportional-derivative] controllers for a class of fractional order systems
Automatica, 2013Co-Authors: Vahid Badri, Mohammad Saleh TavazoeiAbstract:Abstract This paper deals with a method recently proposed for tuning fractional order [proportional–derivative] (FO-[PD]) controllers. Using this tuning method, the tuned FO-[PD] controller can ensure the desired phase margin, the desired gain crossover frequency, and the flatness of the phase Bode Plot at such a frequency. In the present paper, the achievable region of this tuning method in the gain crossover frequency–phase margin plane is obtained analytically. Also, the continuity of this region and uniqueness of the tuned parameters are investigated. Moreover, the achievable region of the aforementioned tuning method in the presence of time delay in the feedback loop is found.