scholarly journals Development of a Novel Latching-Type Electromagnetic Actuator for Applications in Minimally Invasive Surgery

Actuators ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 41 ◽  
Author(s):  
HaoChen Wang ◽  
Ali K. El Wahed
Keyword(s):  
Magnetic Circuit ◽  
Single Port ◽  
Short Pulse ◽  
Healthcare Sector ◽  
Electromagnetic Actuator ◽  
Finite Element Analyses ◽  
Field Interaction ◽  
Magnetic Forces ◽  
Magnetic Shell ◽  
The Magnetic Field

Single-port laparoscopic surgery (SLS), which utilises one major incision, has become increasingly popular in the healthcare sector in recent years. However, this technique suffers from several problems particularly the inability of current SLS instruments to provide the optimum angulation that is required during SLS operations. In this paper, the development of a novel latching-type electromagnetic actuator is reported, which is aimed to enhance the function of SLS instruments. This new actuator is designed to be embedded at selected joints along SLS instruments to enable the surgeon to transform them from their straight and slender shape to an articulated posture. The developed electromagnetic actuator is comprised of electromagnetic coil elements, a solid magnetic shell, and a permanent magnet used to enhance the magnetic field interaction along the force generation path and also to provide the latching effect. In this investigation, electromagnetic finite element analyses were conducted to design and optimise the actuator’s electromagnetic circuit. In addition, the performance of the new actuator was numerically and experimentally determined when output magnetic forces and torques in excess of 9 N and 45 mNm, respectively together with an angulation of 30° were achieved under a short pulse of current supply to the magnetic circuit of the actuator.

scholarly journals Finite Element Analysis of Magnetic Field Exciter for Direct Testing of Magnetocaloric Materials’ Properties

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2792
Author(s):  
Wieslaw Lyskawinski ◽  
Wojciech Szelag ◽  
Cezary Jedryczka ◽  
Tomasz Tolinski
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Circuit ◽  
Homogeneous Magnetic Field ◽  
Element Analysis ◽  
Mcm Testing ◽  
Testing Region ◽  
Magnetocaloric Materials ◽  
Field Excitation ◽  
The Magnetic Field

The paper presents research on magnetic field exciters dedicated to testing magnetocaloric materials (MCMs) as well as used in the design process of magnetic refrigeration systems. An important element of the proposed test stand is the system of magnetic field excitation. It should provide a homogeneous magnetic field with a controllable value of its intensity in the MCM testing region. Several concepts of a magnetic circuit when designing the field exciters have been proposed and evaluated. In the MCM testing region of the proposed exciters, the magnetic field is controlled by changing the structure of the magnetic circuit. A precise 3D field model of electromagnetic phenomena has been developed in the professional finite element method (FEM) package and used to design and analyze the exciters. The obtained results of the calculations of the magnetic field distribution in the working area were compared with the results of the measurements carried out on the exciter prototype. The conclusions resulting from the conducted research are presented and discussed.

Design of an electromagnetic actuator for parametric stiffness excitation

2007 ◽  
Vol 26 (3) ◽  
pp. 800-813 ◽  
Author(s):  
Erich Schmidt ◽  
Wolfgang Paradeiser ◽  
Fadi Dohnal ◽  
Horst Ecker
Keyword(s):  
Finite Element ◽  
Permanent Magnets ◽  
Electromagnetic Actuator ◽  
Finite Element Analyses ◽  
Coil Current ◽  
Content Type ◽  
Electromechanical Device ◽  
Stiffness Variation ◽  
Actuator Design ◽  
First Time

PurposeAn overview is given on design features, numerical modelling and testing of a novel electromagnetic actuator to achieve a controllable stiffness to be used as a device for parametric stiffness excitation.Design/methodology/approachIn principle, the actuator consists of a current driven coil placed between two permanent magnets. Repellent forces are generated between the coil and the magnets, centering the coil between the two magnets. The 2D finite element analyses are carried out to predict the forces generated by this arrangement depending on coil current and coil position. Force measurements are also made using the actual device.FindingsActuator forces as predicted by the finite element analyses are in excellent agreement with the measured data, confirming the validity of the numerical model. Stiffness of the actuator is defined as the increase of force per unit of coil displacement. Actuator stiffness depends linearly on the coil current but in a nonlinear manner on the coil displacement. The performance of the actuator is sufficient to demonstrate the effect of a so‐called parametric anti‐resonance on a test stand.Research limitations/implicationsAlthough the performance of the actuator is satisfactory, there is potential for further improvement of the actuator design.Originality/valueThis paper reports for the first time on an electromechanical device to create a time‐periodic stiffness variation to be used for research in the field of parametrically excited mechanical systems. The device is used to prove experimentally an effect to suppress mechanical vibrations which has been studied so far only in theoretical studies.

scholarly journals Dynamical Galactic Halos

1993 ◽  
Vol 157 ◽  
pp. 415-419
Author(s):  
D. Breitschwerdt ◽  
H.J. Völk ◽  
V. Ptuskin ◽  
V. Zirakashvili
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
The Other ◽  
Galactic Rotation ◽  
Galactic Halos ◽  
Magnetic Forces ◽  
Dynamical Coupling ◽  
Field Lines ◽  
The Magnetic Field ◽  
Open Magnetic Field

It is argued that the description of the magnetic field in halos of galaxies should take into account its dynamical coupling to the other major components of the interstellar medium, namely thermal plasma and cosmic rays (CR's). It is then inevitable to have some loss of gas and CR's (galactic wind) provided that there exist some “open” magnetic field lines, facilitating their escape, and a sufficient level of self-generated waves which couple the particles to the gas. We discuss qualitatively the topology of the magnetic field in the halo and show how galactic rotation and magnetic forces can be included in such an outflow picture.

A Proposed Experiment of Direct Detecting of the Vector Potential within Classical Electrodynamics

1997 ◽  
Vol 11 (12) ◽  
pp. 531-540
Author(s):  
V. Onoochin
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Field ◽  
Charged Particle ◽  
Vector Potential ◽  
Energy Exchange ◽  
Short Pulse ◽  
Classical Electrodynamics ◽  
Direct Influence ◽  
Ultra Short Pulse ◽  
The Magnetic Field

An experiment within the framework of classical electrodynamics is proposed, to demonstrate Boyer's suggestion of a change in the velocity of a charged particle as it passes close to a solenoid. The moving charge is replaced by an ultra-short pulse (USP), whose characteristics should depend on the current in the coil. This dependence results from the exchange of energy between the electromagnetic field of the pulse and the magnetic field within the solenoid. This energy exchange could only be explained, by assuming that the vector potential of the solenoid has a direct influence on the pulse.

A general method for calculating the self-induced magnetic force of an axisymmetric toroidal current

1984 ◽  
Vol 31 (3) ◽  
pp. 415-421
Author(s):  
S. Bobbio ◽  
G. Rubinacci
Keyword(s):  
Approximate Formula ◽  
Magnetic Force ◽  
The Self ◽  
Large Aspect Ratio ◽  
Magnetic Forces ◽  
Correct Calculation ◽  
Peripheral Surface ◽  
Ratio Limit ◽  
The Magnetic Field ◽  
General Method

A method is presented for computing the class of axisymmetric current distributions flowing in a torus whose peripheral surface is a flux surface for the magnetic field produced by the current itself. The method allows the correct calculation of the ‘self-induced’ magnetic forces arising from the interaction between these currents and their own field. The general expression for the self-induced force is given and an approximate formula is presented in the large aspect-ratio limit.

Design and Analysis of a Vibration-Based Magnetoelectric Energy Harvesting Device

2013 ◽  
Vol 722 ◽  
pp. 75-80 ◽  
Author(s):  
Zhang Zhang ◽  
Xian Zhi Dai ◽  
Yong Wang
Keyword(s):  
Magnetic Field ◽  
Cantilever Beam ◽  
Magnetic Circuit ◽  
Magnetic Field Gradient ◽  
Sensor Nodes ◽  
Ambient Vibration ◽  
Gradient Magnetic Field ◽  
Wireless Sensor Nodes ◽  
The Magnetic Field ◽  
Theoretical Results

An energy harvester is presented to harvest ambient vibration energy using a cantilever beam and multiple Terfenol-D/PMN-PT/Terfenol-D laminate magnetoelectric transducers. The harvester uses eight magnets to make up a magnetic circuit arranged on the free end of the cantilever beam. The magnetic circuit can produce a high gradient magnetic field space. The multiple transducers are placed at the high magnetic field gradient position to make the best use of the magnetic field produced by the magnets. The nonlinear vibration and electrical-output performances of the harvester at resonance are analyzed. The theoretical results indicate that the prototype can produce a load power of 7.619 mW, which is sufficient to supply low consumption wireless sensor nodes.

Development of a double magnetic circuit yield stress measurement device for magnetorheological fluid

2016 ◽  
Vol 28 (10) ◽  
pp. 1249-1259 ◽  
Author(s):  
Xiang-Fan Wu ◽  
Xing-Ming Xiao ◽  
Zu-Zhi Tian ◽  
Fei Chen ◽  
Jian Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Yield Stress ◽  
Magnetic Circuit ◽  
Stress Measurement ◽  
Magnetorheological Fluid ◽  
High Yield ◽  
Magnetic Field Measurement ◽  
Measurement Device ◽  
Accuracy And Repeatability ◽  
The Magnetic Field

On the basis of shear working mode of magnetorheological fluid, in this article, a novel temperature controllable yield stress measurement device is designed, and the double magnetic circuit structure and the heating structure are proposed. And then, the magnetic field and temperature field of the measurement device are simulated, respectively, by the finite element method. Furthermore, several experiments are carried out to evaluate the magnetic field, measurement precision, and repeatability of the self-designed device. The results indicate that the proposed measurement device has uniform magnetic field distribution and controllable temperature and also has high yield stress testing accuracy and repeatability.

Magnetic Field Analysis of Surface-Mounted Permanent-Magnet Motors

2011 ◽  
Vol 52-54 ◽  
pp. 285-290
Author(s):  
Yi Chang Wu ◽  
Feng Ming Ou ◽  
Bo Wei Lin
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Magnetic Circuit ◽  
Circuit Model ◽  
Field Analysis ◽  
Permanent Magnet Motors ◽  
Element Analysis ◽  
Magnetic Field Analysis ◽  
Field Estimation ◽  
The Magnetic Field

The prediction of the magnetic field is a prerequisite to investigate the motor performance. This paper focuses on the magnetic field estimation of surface-mounted permanent-magnet (SMPM) motors based on two approximations, i.e., the magnetic circuit analysis and the finite-element analysis (FEA). An equivalent magnetic circuit model is applied to analytically evaluate the magnetic field of a SMPM motor with exterior-rotor configuration. The two-dimensional FEA is then applied to numerically calculate the magnetic field and to verify the validity of the magnetic circuit model. The results show that the errors between the analytical predictions and FEA results are less than 6%. It is of benefit to further design purposes and optimization of SMPM motors.

Determination of Magnetic Losses in a Transformer by Wattmetric Method

2020 ◽  
Vol 63 (5) ◽  
pp. 27-31
Author(s):  
Sergey Plotnikov ◽  
Keyword(s):  
Single Phase ◽  
Magnetic Circuit ◽  
Dynamic Measurement ◽  
Frequency Error ◽  
Magnetic Losses ◽  
Empirical Knowledge ◽  
The Magnetic Field ◽  
Good Agreement ◽  
Three Components

The purpose of the article is to describe the methodology for determining the components of losses in the magnetic circuit of a transformer. Based on current empirical knowledge about the extent to which each of the three components of the losses in the steel of the magnetic circuit depends on the frequency of the magnetic field, a wattmetric method for determining these losses has been developed. The method consists in measuring the total losses in the magnetic circuit at three frequencies using the idle experience and calculating the three components of the losses. It does not matter to what extent each component depends on the amplitude of mag-netic induction or other parameters. It has been established that it is advisable to carry out idling experiments in the range of 50 ... 70 Hz, in which there is no dynamic measurement error, and the frequency error of the coefficients of the calculated matrix is negligible. The results obtained for a single-phase transformer are in good agreement with modern ideas about the ratio of the three components of the losses in the magnetic circuit.

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