International Journal of Applied Electromagnetics and Mechanics - Volume 34, issue 4

Authors: Mehrtash, Moein | Shameli, Ehsan | Khamesee, Mir Behrad

Article Type: Research Article

Abstract: Recently, magnetic telemanipulation devices have shown a great deal of promise in such areas as semi-conductor manufacturing, wind tunnels, drug delivery, and many more. However, these devices are generally associated with problems caused by payload variation and uncertainties in the parameters of the system which in turn, have limited the development and application of magnetic telemanipulation technology to its full capacity. This paper addresses and deals with these issues by implementation of a precise position …control method for a magnetic telemanipulation system with high level of uncertainties in its parameters. The levitation system used in this study is primarily designed for performing remote pick and place operations. The levitated object is a 28 gr microrobot capable of grasping and releasing payloads as heavy as 8 gr. To cope with the uncertainties in the modeling and payload variation, a model reference adaptive feedback linearization (MRAFL) controller is designed and its performance compared with an ordinary feedback linearization (FL) controller. Through experimental results it is shown that the MRAFL controller enables the microrobot to grasp and transport a payload as heavy as 30% of its own weight without a considerable effect on its positioning accuracy. In the presence of the payload, the MRAFL controller resulted in a RMS positioning error of 8 μm} compared with 27.9 μm} of the FL controller. The approach presented in this work is versatile as it leads to the modeling and control of a highly nonlinear system through a modular approach that can be applied to a variety of magnetic levitation and telemanipulation systems. Show more

Keywords: Magnetic levitation, Mechatronics, dynamic modeling, feedback linearization, adaptive control, telemanipulation

DOI: 10.3233/JAE-2010-1312

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 34, no. 4, pp. 211-223, 2010

Authors: Greiser, Steffen | Böhm, Valter | Zimmermann, Klaus

Article Type: Research Article

Abstract: Motivated by the technical progress, electromagnetic action principles are more and more used in micro systems. It is well known that the discrete positioning of magnetic beads like ferrofluid droplets can be realised using an array of electromagnets whereat the position of the beads depends on the arrangement of the electromagnets. This paper refers to the analogous positioning of magnetic beads independent from the arrangement of the electromagnets. Therefore a control strategy was designed …to position magnetic beads like ferrofluid droplets, ferrogels or ferroelastomers. The derived control law allows the definition of dynamic properties like time and damping constant. To achieve these properties, the controller is adjusted based on a model of the plant. This model regards the dynamical movement of the mentioned materials in electromagnetic fields and is characterised by simplified, nonlinear, ordinary differential equations. The theoretical results are verified by means of a basic assembly allowing the positioning of spherical ferroelastomers on macro scale. The measurements illustrate that the theoretically derived position controller meets the requirements of a predefined time and damping constant. Show more

Keywords: Position control, feedback linearization, magnetic bead, ferrofluid, ferroelastomer, magnetic force

DOI: 10.3233/JAE-2010-1313

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 34, no. 4, pp. 225-235, 2010

Authors: Bakshi, Amit | Kulkarni, S. V.

Article Type: Research Article

Abstract: Dynamic axial displacement of high voltage (HV) winding disk of a power transformer has been calculated by Green's function approach, when time varying axial electromagnetic forces corresponding to worst case of short circuit condition, are applied. An elaborate analysis of the axial electromagnetic forces and corresponding axial displacement of a top-end disk of HV winding is carried out. Under the action of these time varying forces, the winding moves in the axial direction as a function …of time between radially placed insulation spacers. Between the spacer supports the winding sections can be considered as clamped-clamped (C-C) beams. Static Green's function of such a beam structure is determined first, and convolving it with axial electromagnetic force determines the axial displacement (bending) at any point on the beam for the purpose of verification of the methodology. Dynamic Green's function of the same winding sector is subsequently derived, which is used to obtain displacement of the winding section by convolving it with an applied time varying axial electromagnetic force. The results are verified with commercial FEM software. Show more

Keywords: Axial electromagnetic force, finite element method (FEM), magnetic vector potential, axial displacement, Green's function

DOI: 10.3233/JAE-2010-1314

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 34, no. 4, pp. 237-247, 2010

Authors: Niho, Tomoya | Horie, Tomoyoshi

Article Type: Research Article

Abstract: This paper describes a method for non-contact vibration control of non-ferromagnetic conductive structures using electromagnetic force. This method has potential applications in conventional engineering and medical engineering. Elastic vibration is induced by an electromagnetic force, which is produced by the interaction between a magnetic field and the eddy currents induced by a transient magnetic field. Since the intensity of the electromagnetic force changes with the intensity or time variation of the transient …magnetic field, the amplitude or time variation of the elastic vibration can be controlled by the transient magnetic field. On the other hand, the electromotive force induced by the deformation velocity and magnetic field reduces the vibration, which is referred to as the magnetic damping effect. Since the magnetic damping effect reduces vibration and induces a time delay in the vibration response, consideration of the magnetic damping effect is required for non-contact vibration control of non-ferromagnetic structures using electromagnetic force. In this study, a method for controlling the vibration of non-ferromagnetic conductive structures using electromagnetic force is proposed, which is based on theoretical and one-degree-of-freedom models of vibration with magnetic damping. The parameters of the model are determined on the basis of the coupled eigenvalues obtained from the coupled finite element equation. Feedback control is also used to realize vibration control. In order to examine the validity and performance of the proposed vibration control method, vibration control experiments are carried out for various desired amplitudes and frequencies of vibration. Show more

Keywords: Vibration control, magnetic damping effect, electromagnetic force, coupled problem, elastic vibration

DOI: 10.3233/JAE-2010-1315

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 34, no. 4, pp. 249-264, 2010

Authors: Shan, Xiao-Biao | Yuan, Jiang-Bo | Xie, Tao | Chen, Wei-Shan

Article Type: Research Article

Abstract: This paper presents a mathematical model for designing broadband piezoelectric energy harvesters by integrating multiple piezoelectric bimorphs (MPBs) with different resonant frequencies into a system. The finite element method (FEM) was used to predict the resonant frequencies of the MPBs. To verify the theoretical analysis, the resonant frequencies of the MPBs were measured using an experimental method. The results obtained from theoretical analysis were in very good agreement with those from the FEM and experimental …results. The performance of MPBs is studied in energy harvesting. The results show that the MPBs can effectively increase the output power and enable broadband energy harvesters. Show more

Keywords: Energy harvesting, multiple piezoelectric bimorphs, FEM

DOI: 10.3233/JAE-2010-1317

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 34, no. 4, pp. 265-275, 2010