The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform

Benjamin Shapiro - One of the best experts on this subject based on the ideXlab platform.

  • planar steering of a single ferrofluid drop by optimal minimum power dynamic feedback control of four Electromagnets at a distance
    Journal of Magnetism and Magnetic Materials, 2011
    Co-Authors: Roland Probst, Arash Komaee, Alek Nacev, Zachary Cummins, Benjamin Shapiro
    Abstract:

    Abstract Any single permanent magnet or electromagnet will always attract a magnetic fluid. For this reason it is difficult to precisely position and manipulate ferrofluid at a distance from magnets. We develop and experimentally demonstrate optimal (minimum electrical power) 2-dimensional manipulation of a single droplet of ferrofluid by feedback control of 4 external Electromagnets. The control algorithm we have developed takes into account, and is explicitly designed for, the nonlinear (fast decay in space, quadratic in magnet strength) nature of how the magnets actuate the ferrofluid, and it also corrects for electromagnet charging time delays. With this control, we show that dynamic actuation of Electromagnets held outside a domain can be used to position a droplet of ferrofluid to any desired location and steer it along any desired path within that domain—an example of precision control of a ferrofluid by magnets acting at a distance.

  • Steering a ferromagnetic particle by magnetic feedback control: Algorithm design and validation
    Proceedings of the 2010 American Control Conference ACC 2010, 2010
    Co-Authors: Arash Komaee, Benjamin Shapiro
    Abstract:

    We present results for planar manipulation of a single drop of magnetic nano-particles (a ferrofluid) in a liquid by feedback control of an array of Electromagnets. Control design is based on a first-principles physical model of the magnetic fields, the resulting magnetic forces, and opposing viscous drag on the ferrofluidic drop, and it exploits the nonlinear (quadratic) nature of the dependence of the magnetic force on the electromagnet actuations. An ability to control the droplet along arbitrary trajectories is verified both in simulations and in an experiment. © 2010 AACC.

Masaaki Sakui - One of the best experts on this subject based on the ideXlab platform.

  • Three-Dimensional Motion of a Small Object by Using a New Magnetic Levitation System Having Four I-Shaped Electromagnets
    IEEE Transactions on Magnetics, 2008
    Co-Authors: Takahisa Ohji, Hiroaki Hara, Kenji Amei, Masaaki Sakui
    Abstract:

    In common active magnetic levitation systems, a floating object is controlled stably by an electromagnet with a narrow air-gap, which reduces the leakage flux. However, in order to move a floating object dynamically, it is necessary to arrange Electromagnets for horizontal motion and to make the air-gap wide for vertical motion at the expense of leakage flux. In this paper, we propose a novel magnetic levitation system having a compact electromagnet composed of four I-shaped Electromagnets. We report constructional features, control techniques, and three-dimensional motion of the floating object.

  • application of lorentz force to a magnetic levitation system for a non magnetic thin plate
    Journal of Materials Processing Technology, 2007
    Co-Authors: Takahisa Ohji, Kenji Amei, Takashi Shinkai, Masaaki Sakui
    Abstract:

    Abstract This paper proposes a new magnetic levitation system using both Lorentz force and Coulomb force for a non-magnetic thin plate. The eddy current induced in a conductive plate generates not only the repulsive force between an ac electromagnet and the plate but also the heat loss. To take a new levitation force different from that Coulomb force, Electromagnets was arranged at just sides of the eddy current path. In this case, since the magnetic flux act as vector product to the eddy current, quasi-static Lorentz forces are generated to the plate effectively. First, for verifying the mechanism of the generation of quasi-static Lorentz forces, experimental equipment having three U-shape ac Electromagnets was fabricated. As a result, new forces equivalent to the Lorentz forces, which was proportional to induced currents of additional Electromagnets, was extracted. Further, the tendency of forces verified in that experiment was also verified by finite element analysis.

Arash Komaee - One of the best experts on this subject based on the ideXlab platform.

  • planar steering of a single ferrofluid drop by optimal minimum power dynamic feedback control of four Electromagnets at a distance
    Journal of Magnetism and Magnetic Materials, 2011
    Co-Authors: Roland Probst, Arash Komaee, Alek Nacev, Zachary Cummins, Benjamin Shapiro
    Abstract:

    Abstract Any single permanent magnet or electromagnet will always attract a magnetic fluid. For this reason it is difficult to precisely position and manipulate ferrofluid at a distance from magnets. We develop and experimentally demonstrate optimal (minimum electrical power) 2-dimensional manipulation of a single droplet of ferrofluid by feedback control of 4 external Electromagnets. The control algorithm we have developed takes into account, and is explicitly designed for, the nonlinear (fast decay in space, quadratic in magnet strength) nature of how the magnets actuate the ferrofluid, and it also corrects for electromagnet charging time delays. With this control, we show that dynamic actuation of Electromagnets held outside a domain can be used to position a droplet of ferrofluid to any desired location and steer it along any desired path within that domain—an example of precision control of a ferrofluid by magnets acting at a distance.

  • Steering a ferromagnetic particle by magnetic feedback control: Algorithm design and validation
    Proceedings of the 2010 American Control Conference ACC 2010, 2010
    Co-Authors: Arash Komaee, Benjamin Shapiro
    Abstract:

    We present results for planar manipulation of a single drop of magnetic nano-particles (a ferrofluid) in a liquid by feedback control of an array of Electromagnets. Control design is based on a first-principles physical model of the magnetic fields, the resulting magnetic forces, and opposing viscous drag on the ferrofluidic drop, and it exploits the nonlinear (quadratic) nature of the dependence of the magnetic force on the electromagnet actuations. An ability to control the droplet along arbitrary trajectories is verified both in simulations and in an experiment. © 2010 AACC.

Nagayoshi Kasashima - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of Driving Currents of Electromagnets To Rotate Spherical Motors
    2018 International Symposium on Power Electronics Electrical Drives Automation and Motion (SPEEDAM), 2018
    Co-Authors: Akio Gofuku, Yu Yamamoto, Tomoaki Yano, Nagayoshi Kasashima
    Abstract:

    A spherical motor has advantageous features to construct a mechanism with multi-degree of freedom because it can rotate in any direction and the rotation center coincides with its geometrical center. This paper deals with a spherical motor such that permanent magnets are arranged on the surface of its rotor and Electromagnets are arranged in the stator. When more than three linear-independent Electromagnets are installed in this type of spherical motor, an optimization problem should be solved under some constraint conditions and an objective function. This paper proposes a technique to solve the optimization problem in order to calculate the currents to Electromagnets for each relative rotation angle between the rotor and the stator by applying the generalized reduced gradient method. The technique makes possible to use a convex function as the objective function. The applicability of the proposed technique is demonstrated by an example to calculate the currents to Electromagnets for a spherical motor that twelve permanent magnets and ten Electromagnets are installed.

  • Driving technique of Electromagnets to rotate spherical motors based on torque map
    2016 International Symposium on Power Electronics Electrical Drives Automation and Motion (SPEEDAM), 2016
    Co-Authors: Akio Gofuku, Yu Yamamoto, Tomoaki Yano, Nagayoshi Kasashima
    Abstract:

    This study develops a technique for rotation control of spherical motors driven by electromagnetic forces. The technique uses the data of generated torque per unit current and cogging torque of an electromagnet that are obtained beforehand at relative positions between the electromagnet and the rotor. An electromagnet placed on the stator of a spherical motor gives two kinds of rotation torques to the rotor. One is the torque by flowing current to the electromagnet. The other is the cogging torque that a permanent magnet on the rotor attracts the iron core of the electromagnet. The torque map expresses the two kinds of rotation torques when the unit current flows to an electromagnet in its various relative position to the rotor. In order to obtain the currents of Electromagnets in the case that there are more than three Electromagnets on the stator, this paper proposes a technique applying the Lagrange multiplier method under a constraint condition. This paper shows an example to obtain the currents of Electromagnets by the proposed technique in the case that five Electromagnets are arranged at the vertices of regular pentagon.

Takahisa Ohji - One of the best experts on this subject based on the ideXlab platform.

  • Three-Dimensional Motion of a Small Object by Using a New Magnetic Levitation System Having Four I-Shaped Electromagnets
    IEEE Transactions on Magnetics, 2008
    Co-Authors: Takahisa Ohji, Hiroaki Hara, Kenji Amei, Masaaki Sakui
    Abstract:

    In common active magnetic levitation systems, a floating object is controlled stably by an electromagnet with a narrow air-gap, which reduces the leakage flux. However, in order to move a floating object dynamically, it is necessary to arrange Electromagnets for horizontal motion and to make the air-gap wide for vertical motion at the expense of leakage flux. In this paper, we propose a novel magnetic levitation system having a compact electromagnet composed of four I-shaped Electromagnets. We report constructional features, control techniques, and three-dimensional motion of the floating object.

  • application of lorentz force to a magnetic levitation system for a non magnetic thin plate
    Journal of Materials Processing Technology, 2007
    Co-Authors: Takahisa Ohji, Kenji Amei, Takashi Shinkai, Masaaki Sakui
    Abstract:

    Abstract This paper proposes a new magnetic levitation system using both Lorentz force and Coulomb force for a non-magnetic thin plate. The eddy current induced in a conductive plate generates not only the repulsive force between an ac electromagnet and the plate but also the heat loss. To take a new levitation force different from that Coulomb force, Electromagnets was arranged at just sides of the eddy current path. In this case, since the magnetic flux act as vector product to the eddy current, quasi-static Lorentz forces are generated to the plate effectively. First, for verifying the mechanism of the generation of quasi-static Lorentz forces, experimental equipment having three U-shape ac Electromagnets was fabricated. As a result, new forces equivalent to the Lorentz forces, which was proportional to induced currents of additional Electromagnets, was extracted. Further, the tendency of forces verified in that experiment was also verified by finite element analysis.