The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Ahmet Ozkan Ozer - One of the best experts on this subject based on the ideXlab platform.
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Modeling and Controlling an Active Constrained Layer (ACL) Beam Actuated by Two Voltage Sources With/Without Magnetic Effects
IEEE Transactions on Automatic Control, 2017Co-Authors: Ahmet Ozkan OzerAbstract:A fully dynamic three-layer active constrained layer (ACL) beam is modeled for cantilevered boundary conditions by using a thorough variational approach. The Rao-Nakra thin compliant layer assumptions are adopted to model the sandwich structure, and all Magnetic Effects for the piezoelectric layers are retained. The piezoelectric layers are activated by two different voltage sources. When there are no “mechanical” boundary forces acting in the longitudinal direction, it is shown that the system with certain parameter combinations is not uniformly strongly stabilizable by the B* - type feedback controller, which is the total current accumulated at the electrodes for the piezoelectric layers. However, as the Magnetic Effects are ignored (electrostatic assumption), the closed-loop system with all mechanical feedback controllers is shown to be uniformly exponentially stable.
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Semigroup well-posedness of a voltage controlled active constrained layered (ACL) beam with Magnetic Effects
2016 American Control Conference (ACC), 2016Co-Authors: Ahmet Ozkan OzerAbstract:The layered smart composites involving a piezoelectric layer are traditionally activated by a voltage source, and the Magnetic Effects are totally ignored since these Effects are relatively smaller in comparison to electrical and mechanical Effects. However, recent results for even a single piezoelectric beam show that ignoring these Effects may cause uncontrollable and unstabilizable systems. In this paper, a variational approach is used to derive a voltage-controlled Rao-Nakra type active constrained layer model. All Magnetic Effects due to the full set of Maxwell's equations are included. It is shown that the proposed model can be put into the semigroup formulation, i.e. ẋ = Ax + Bu; and is well-posed in the corresponding energy space. Moreover, the observed quantity due to the observation operator B* (corresponding to the control operator B with the voltage control) is totally electrical.
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ACC - Semigroup well-posedness of a voltage controlled active constrained layered (ACL) beam with Magnetic Effects
2016 American Control Conference (ACC), 2016Co-Authors: Ahmet Ozkan OzerAbstract:The layered smart composites involving a piezoelectric layer are traditionally activated by a voltage source, and the Magnetic Effects are totally ignored since these Effects are relatively smaller in comparison to electrical and mechanical Effects. However, recent results for even a single piezoelectric beam show that ignoring these Effects may cause uncontrollable and unstabilizable systems. In this paper, a variational approach is used to derive a voltage-controlled Rao-Nakra type active constrained layer model. All Magnetic Effects due to the full set of Maxwell's equations are included. It is shown that the proposed model can be put into the semigroup formulation, i.e. ẋ = Ax + Bu; and is well-posed in the corresponding energy space. Moreover, the observed quantity due to the observation operator B* (corresponding to the control operator B with the voltage control) is totally electrical.
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Modeling and related results for current-actuated piezoelectric beams by including Magnetic Effects
arXiv: Analysis of PDEs, 2016Co-Authors: K. Morris, Ahmet Ozkan OzerAbstract:Piezo-electric material can be controlled with current as the electrical variable, instead of voltage. The main purpose of this paper is to derive the governing equations for a current-controlled piezo-electric beam and to investigate stabilizability. Besides the consideration of current control, there are several new aspects to the model here. Most significantly, Magnetic Effects are included. For the electroMagnetic part of the model, electrical potential and Magnetic vector potential are chosen to be quadratic-through thickness to include the induced Effects of the electroMagnetic field. Two sets of decoupled system of partial differential equations are obtained; one for stretching motion and another one for bending motion. Hamilton's principle is used to derive a boundary value problem that models a single piezo-electric beam actuated by a charge (or current) source at the electrodes. Current or charge controllers at the electrodes can only control the stretching motion. Attention is therefore focused on control of the stretching equations in this paper. It is shown that the Lagrangian of the beam is invariant under certain transformations. A Coulomb-type gauge condition which is widely used in the electroMagnetic theory is used here. This gauge condition decouples the electrical potential equation from the equations of the Magnetic potential. A semigroup approach is used to prove that the Cauchy problem is well-posed. Unlike the voltage or charge actuation, a bounded control operator in the natural energy space is obtained in the current actuation case. The paper concludes with analysis of stabilizability and comparison with other actuation approaches and models.
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Further stabilization and exact observability results for voltage-actuated piezoelectric beams with Magnetic Effects
Mathematics of Control Signals and Systems, 2015Co-Authors: Ahmet Ozkan OzerAbstract:It is well known that Magnetic energy of the piezoelectric beam is relatively small, and it does not change the overall dynamics. Therefore, the models, relying on electrostatic or quasi-static approaches, completely ignore the Magnetic energy stored/produced in the beam. A single piezoelectric beam model without the Magnetic Effects is known to be exactly observable and exponentially stabilizable in the energy space. However, the model with the Magnetic Effects is proved to be not exactly observable/exponentially stabilizable in the energy space for almost all choices of material parameters. Moreover, even strong stability is not achievable for many values of the material parameters. In this paper, it is shown that the uncontrolled system is exactly observable in a space larger than the energy space. Then, by using a $$B^*$$ B ∗ -type feedback controller, explicit polynomial decay estimates are obtained for more regular initial data. Unlike the classical counterparts, this choice of feedback corresponds to the current flowing through the electrodes, and it matches better with the physics of the model. The results obtained in this manuscript have direct implications on the controllability/stabilizability of smart structures such as elastic beams/plates with piezoelectric patches and the active constrained layer (ACL) damped beams/plates.
K. Morris - One of the best experts on this subject based on the ideXlab platform.
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Modeling and related results for current-actuated piezoelectric beams by including Magnetic Effects
arXiv: Analysis of PDEs, 2016Co-Authors: K. Morris, Ahmet Ozkan OzerAbstract:Piezo-electric material can be controlled with current as the electrical variable, instead of voltage. The main purpose of this paper is to derive the governing equations for a current-controlled piezo-electric beam and to investigate stabilizability. Besides the consideration of current control, there are several new aspects to the model here. Most significantly, Magnetic Effects are included. For the electroMagnetic part of the model, electrical potential and Magnetic vector potential are chosen to be quadratic-through thickness to include the induced Effects of the electroMagnetic field. Two sets of decoupled system of partial differential equations are obtained; one for stretching motion and another one for bending motion. Hamilton's principle is used to derive a boundary value problem that models a single piezo-electric beam actuated by a charge (or current) source at the electrodes. Current or charge controllers at the electrodes can only control the stretching motion. Attention is therefore focused on control of the stretching equations in this paper. It is shown that the Lagrangian of the beam is invariant under certain transformations. A Coulomb-type gauge condition which is widely used in the electroMagnetic theory is used here. This gauge condition decouples the electrical potential equation from the equations of the Magnetic potential. A semigroup approach is used to prove that the Cauchy problem is well-posed. Unlike the voltage or charge actuation, a bounded control operator in the natural energy space is obtained in the current actuation case. The paper concludes with analysis of stabilizability and comparison with other actuation approaches and models.
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Modeling and Stabilizability of Voltage-Actuated Piezoelectric Beams with Magnetic Effects
Siam Journal on Control and Optimization, 2014Co-Authors: K. Morris, Ahmet Ozkan OzerAbstract:Models for piezoelectric beams and structures with piezoelectric patches generally ignore Magnetic Effects. This is because the Magnetic energy has a relatively small effect on the overall dynamics. Piezoelectric beam models are known to be exactly observable and can be exponentially stabilized in the energy space by using a mechanical feedback controller. In this paper, a variational approach is used to derive a model for a piezoelectric beam that includes Magnetic Effects. It is proved that the partial differential equation model is well-posed. Magnetic Effects have a strong effect on the stabilizability of the control system. For almost all system parameters the piezoelectric beam can be strongly stabilized, but it is not exponentially stabilizable in the energy space. Strong stabilization is achieved using only electrical feedback. Furthermore, using the same electrical feedback, an exponentially stable closed-loop system can be obtained for a set of system parameters of zero Lebesgue measure. These r...
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ACC - Modeling an elastic beam with piezoelectric patches by including Magnetic Effects
2014 American Control Conference, 2014Co-Authors: A. Ozkan Ozer, K. MorrisAbstract:Models for piezoelectric beams using Euler-Bernoulli small displacement theory predict the dynamics of slender beams at the low frequency accurately but are insufficient for beams vibrating at high frequencies or beams with low length-to-width aspect ratios. A more thorough model that includes the Effects of rotational inertia and shear strain, Mindlin-Timoshenko small displacement theory, is needed to predict the dynamics more accurately for these cases. Moreover, existing models ignore the Magnetic Effects since the Magnetic Effects are relatively small. However, it was shown recently [10] that these Effects can substantially change the controllability and stabilizability properties of even a single piezoelectric beam. In this paper, we use a variational approach to derive models that include Magnetic Effects for an elastic beam with two piezoelectric patches actuated by different voltage sources. Both Euler-Bernoulli and Mindlin-Timoshenko small displacement theories are considered. Due to the Magnetic Effects, the equations are quite different from the standard equations.
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CDC - Strong stabilization of piezoelectric beams with Magnetic Effects
52nd IEEE Conference on Decision and Control, 2013Co-Authors: K. Morris, A. Ozkan OzerAbstract:It is widely accepted in the literature that Magnetic Effects in the piezoelectric beams is relatively small, and does not change the overall dynamics. Therefore, most models for piezoelectric beams completely ignore the Magnetic energy. These models are known to be exponentially stabilizable by a mechanical feedback controller in the energy space. In this paper, we use a variational approach to derive the differential equations and boundary conditions that model a single piezoelectric beam with Magnetic Effects. Next, we show that the resulting control system can be formulated as a port-Hamiltonian system and is hence well-posed. Finally, by using only an electrical feedback controller (the current flowing through the electrodes), we show that the closed-loop system is strongly stable in the energy space for a dense set of system parameters. The difference between this result and that for models that neglect Magnetic Effects is discussed.
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Strong stabilization of piezoelectric beams with Magnetic Effects
52nd IEEE Conference on Decision and Control, 2013Co-Authors: K. Morris, Özkan A. ÖzerAbstract:It is widely accepted in the literature that Magnetic Effects in the piezoelectric beams is relatively small, and does not change the overall dynamics. Therefore, most models for piezoelectric beams completely ignore the Magnetic energy. These models are known to be exponentially stabilizable by a mechanical feedback controller in the energy space. In this paper, we use a variational approach to derive the differential equations and boundary conditions that model a single piezoelectric beam with Magnetic Effects. Next, we show that the resulting control system can be formulated as a port-Hamiltonian system and is hence well-posed. Finally, by using only an electrical feedback controller (the current flowing through the electrodes), we show that the closed-loop system is strongly stable in the energy space for a dense set of system parameters. The difference between this result and that for models that neglect Magnetic Effects is discussed.
Özkan A. Özer - One of the best experts on this subject based on the ideXlab platform.
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Modeling an elastic beam with piezoelectric patches by including Magnetic Effects
2014 American Control Conference, 2014Co-Authors: Özkan A. Özer, K. A. MorrisAbstract:Models for piezoelectric beams using Euler-Bernoulli small displacement theory predict the dynamics of slender beams at the low frequency accurately but are insufficient for beams vibrating at high frequencies or beams with low length-to-width aspect ratios. A more thorough model that includes the Effects of rotational inertia and shear strain, Mindlin-Timoshenko small displacement theory, is needed to predict the dynamics more accurately for these cases. Moreover, existing models ignore the Magnetic Effects since the Magnetic Effects are relatively small. However, it was shown recently [10] that these Effects can substantially change the controllability and stabilizability properties of even a single piezoelectric beam. In this paper, we use a variational approach to derive models that include Magnetic Effects for an elastic beam with two piezoelectric patches actuated by different voltage sources. Both Euler-Bernoulli and Mindlin-Timoshenko small displacement theories are considered. Due to the Magnetic Effects, the equations are quite different from the standard equations.
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Strong stabilization of piezoelectric beams with Magnetic Effects
52nd IEEE Conference on Decision and Control, 2013Co-Authors: K. Morris, Özkan A. ÖzerAbstract:It is widely accepted in the literature that Magnetic Effects in the piezoelectric beams is relatively small, and does not change the overall dynamics. Therefore, most models for piezoelectric beams completely ignore the Magnetic energy. These models are known to be exponentially stabilizable by a mechanical feedback controller in the energy space. In this paper, we use a variational approach to derive the differential equations and boundary conditions that model a single piezoelectric beam with Magnetic Effects. Next, we show that the resulting control system can be formulated as a port-Hamiltonian system and is hence well-posed. Finally, by using only an electrical feedback controller (the current flowing through the electrodes), we show that the closed-loop system is strongly stable in the energy space for a dense set of system parameters. The difference between this result and that for models that neglect Magnetic Effects is discussed.
Pedro J. García-r - One of the best experts on this subject based on the ideXlab platform.
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Thermo-Magnetic Effects in Nano-Scaled MOSFET: An Experimental, Modeling, and Simulation Approach
IEEE Journal of the Electron Devices Society, 2015Co-Authors: Gabriela A. Rodríguez-ruiz, Edmundo A. Gutiérrez-d, Arturo L. Sarmiento-reyes, Zlatan Stanojevic, Hans Kosina, Fernando J. Guarin, Pedro J. García-rAbstract:A numerical simulation methodology for incorporating thermo-Magnetic Effects on the MOSFET gate tunneling current is introduced. The methodology is based on the solution of the Schrödinger-Poisson coupled system, which allows simulating the influence of a static Magnetic field and temperature on the wave functions and gate tunneling current of MOSFET devices. In addition to the preliminary results on the simulation methodology, experimental results on the effect of the Magnetic field on the subthreshold slope, the off-current, and transconductance, are also introduced. The proposed simulation methodology, in conjunction with experimental data, is useful for device degradation and reliability studies in nano-scaled MOSFET devices. This experimental characterization technique sets also the basis for the development of a Magnetic force nanoscopy technique, where the conductive properties, thanks to the Lorentz force, can be two-dimensionally mapped over the nano-scaled MOSFET channel plane.
Gabriela A. Rodríguez-ruiz - One of the best experts on this subject based on the ideXlab platform.
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Thermo-Magnetic Effects in Nano-Scaled MOSFET: An Experimental, Modeling, and Simulation Approach
IEEE Journal of the Electron Devices Society, 2015Co-Authors: Gabriela A. Rodríguez-ruiz, Edmundo A. Gutiérrez-d, Arturo L. Sarmiento-reyes, Zlatan Stanojevic, Hans Kosina, Fernando J. Guarin, Pedro J. García-rAbstract:A numerical simulation methodology for incorporating thermo-Magnetic Effects on the MOSFET gate tunneling current is introduced. The methodology is based on the solution of the Schrödinger-Poisson coupled system, which allows simulating the influence of a static Magnetic field and temperature on the wave functions and gate tunneling current of MOSFET devices. In addition to the preliminary results on the simulation methodology, experimental results on the effect of the Magnetic field on the subthreshold slope, the off-current, and transconductance, are also introduced. The proposed simulation methodology, in conjunction with experimental data, is useful for device degradation and reliability studies in nano-scaled MOSFET devices. This experimental characterization technique sets also the basis for the development of a Magnetic force nanoscopy technique, where the conductive properties, thanks to the Lorentz force, can be two-dimensionally mapped over the nano-scaled MOSFET channel plane.
