Design of a Xenia Coral Robot Using a High-Stroke Compliant Linear Electromagnetic Actuator

2021 ◽  
Vol 1 (3) ◽  
Author(s):  
Noah Kohls ◽  
Ibrahim Abdeally ◽  
Bryan P. Ruddy ◽  
Yi Chen Mazumdar
Keyword(s):  
Liquid Gallium ◽  
Electromagnetic Actuator ◽  
Robot Dynamics ◽  
Arc Length ◽  
Electromagnetic Actuators ◽  
Magnetic Forces ◽  
Electromagnetic Linear Actuator ◽  
Identification Techniques ◽  
Compliant Actuator ◽  
Actuator Design

Abstract Electromagnetic actuators provide fast speed, large forces, high strokes, and wide bandwidths. Most designs, however, are constructed from rigid components, making these benefits inaccessible for many soft robotics applications. In this work, we develop a new soft electromagnetic linear actuator using liquid gallium–indium for the conductor and neodymium–iron–boron and polymer composites for the permanent magnet. When combined in a solenoid configuration, high strokes can be generated using entirely soft components. To emulate the pulsing motion of Xenia coral arms, we develop an additional soft flexure system that converts the linear translation to rotary motion. The design and fabrication of the electromagnetic actuator and compliant flexure are first described. Models for the magnetic forces and the joint kinematics are then developed and compared with the experimental results. Finally, the robot dynamics are analyzed using stochastic system identification techniques. Results show that the compliant actuator is able to achieve an 18 mm stroke, allowing the soft arms to bend up to 120 deg. This further enables the tips of the arms to traverse an arc length of 42 mm. Bandwidths up to 30 Hz were also observed. While this article focuses on emulating a biological system, this highly deformable actuator design can also be utilized for fully soft grasping or wearables applications.

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.

OPTIMIZATION OF THE FORCE CHARACTERISTIC OF ROTARY MOTION TYPE OF ELECTROMAGNETIC ACTUATOR BASED ON FINITE ELEMENT ANALYSIS

2016 ◽  
Vol 78 (9) ◽  
Author(s):  
Izzati Yusri ◽  
Mariam Md Ghazaly ◽  
Esmail Ali Ali Alandoli ◽  
Mohd Fua'ad Rahmat ◽  
Zulkeflee Abdullah ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Thrust Force ◽  
Rotary Motion ◽  
Electromagnetic Actuator ◽  
Element Analysis ◽  
Electromagnetic Actuators ◽  
Motion Type

This paper addresses a rotary motion type of electromagnetic actuator that compares two types of electromagnetic actuators; i.e the Permanent Magnet Switching Flux (PMSF) and the Switching Reluctance (SR) actuator. The Permanent Magnet Switching Flux (PMSF) actuator is the combination of permanent magnets (PM) and the Switching Reluctance (SR) actuator. The force optimizations are accomplished by manipulating the actuator parameters; i.e. (i) the poles ratio of the stator and rotor; (ii) the actuator’s size; (iii) the number of winding turns; and (iv) the air gap thickness between the stator and rotor through Finite Element Analysis Method (FEM) using the ANSYS Maxwell 3D software. The materials implemented in the actuator’s parameters optimizations are readily available materials, especially in Malaysia. The excitation current used in FEM analysis for both actuators was between 0A and 2A with interval of 0.25A. Based on the FEM analyses, the best result was achieved by the Permanent Magnet Switching Flux (PMSF) actuator. The PMSF actuator produced the largest magnetostatic thrust force (4.36kN) once the size is scaled up to 100% with the input current, 2A respectively. The maximum thrust force generated by the Switching Reluctance (SR) actuator was 168.85μN, which is significantly lower in compared to the results of the PMSF actuator. 

Stability analysis of rigid rotors supported by gas foil bearings coupled with electromagnetic actuators

2019 ◽  
Vol 234 (2) ◽  
pp. 427-443 ◽  
Author(s):  
Kamal Kumar Basumatary ◽  
Gaurav Kumar ◽  
Karuna Kalita ◽  
Sashindra K Kakoty
Keyword(s):  
Stability Analysis ◽  
Equations Of Motion ◽  
Electromagnetic Actuator ◽  
Electromagnetic Actuators ◽  
Foil Bearings ◽  
Damping Characteristics ◽  
Foil Bearing ◽  
Model Combining ◽  
The Stability ◽  
Rigid Rotors

Rotors supported on gas foil bearings have low damping characteristics, which limits its application. A possible solution could be an integration of a gas foil bearing with an electromagnetic actuator. This paper discusses the effect of electromagnetic actuators on the stability of a rotor supported on gas foil bearings. A coupled dynamic model combining the dynamics of gas foil bearing and electromagnetic actuator has been developed. The fluid film forces from the gas foil bearings and the electromagnetic forces from the electromagnetic actuators are integrated into the equations of motion of the rotor. The sub-synchronous vibration present in case of conventional gas foil bearings is reduced and the stability band of the rotor is increased due to the implementation of electromagnetic actuator.

FORCE CHARACTERIZATION OF A TUBULAR LINEAR ELECTROMAGNETIC ACTUATOR USING FINITE ELEMENT ANALYSIS METHOD (FEM)

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
Mariam Md Ghazaly ◽  
Tawfik Ahmed Yahya ◽  
Aliza Che Amran ◽  
Zulkeflee Abdullah ◽  
Mohd Amran Md Ali ◽  
...  
Keyword(s):  
Finite Element ◽  
Ansys Software ◽  
Element Analysis ◽  
Electromagnetic Actuators ◽  
Halbach Array ◽  
Output Characteristics ◽  
Actuator Design ◽  
Force Displacement ◽  
The Magnetic Field

This paper presents an extensive characterising study of two novel electromagnetic actuators, each with different constructions and characteristics aiming to analyse the behaviour and output characteristics of the two designs. The two actuators are Tubular Linear Reluctance Actuator (TLRA) and Tubular Linear Permanent magnet (TLPM) with Halbach array actuator. The study covered the variation of three parameters, which are the actuator air gap, number of turns and actuator size. A comparative section was also presented for the purpose of comparison. The study concentrated extensively on the two characteristics of both actuators known as output thrust force and working range as they are considered as two main concerns of any actuator design. The simulation was used to show the differences between the two designs in many design aspects such as force, displacement and effects of parameters variations. The applied simulation was performed using 3D Finite-element Ansys software, which is capable of showing the magnetic field distribution in the whole actuator and predicting the strength and length of the output stroke.

Combination Axial and Radial Active Magnetic Bearing With Improved Axial Bandwidth

2012 ◽  
Author(s):  
Alexei V. Filatov ◽  
Lawrence A. Hawkins
Keyword(s):  
Structural Integrity ◽  
Electrical Current ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Phase Lag ◽  
Axial Loads ◽  
Electromagnetic Actuators ◽  
Current Path ◽  
Force Reduction ◽  
Actuator Design

Homopolar Permanent-Magnet-Biased Combination Axial and Radial Electromagnetic Actuators used in Active Magnetic Bearings (AMBs) have several advantages over arrangements of separate axial and radial actuators including shorter length, lower part count, lower cost and better rotordynamic response. However, these actuators may require higher-order compensators in applications with significant dynamic axial loads due to somewhat lower axial bandwidth. One of the reasons for a lower axial bandwidth is having the axial magnetic control flux flowing through an opening in a radial actuator assembled from insulated electrical-steel laminations stacked axially. Whenever this flux changes in time, it induces an electrical current in each lamination which is responsible for the dynamic axial force reduction and an additional phase lag. In an improved actuator design, a current path in each lamination is interrupted by a single slot located between two radial control poles. In order to maintain structural integrity of the stack and magnetic conductivity between the radial poles, the slot position is rotated by 90 degrees between each subsequent lamination in the stack. The solution has been evaluated in a test actuator with 3000N axial and 1200N radial load capacities. 7dB gain improvement and 15 degrees phase improvement at 30Hz have been demonstrated.

Electromagnetic actuator design for the control of light structures

2010 ◽  
Vol 6 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Johan Der Hagopian ◽  
Jarir Mahfoud
Keyword(s):  
Electromagnetic Actuator ◽  
Actuator Design

Research on Parameter Identification of Electromagnetic Actuator for Diesel Speed Governing

2013 ◽  
Vol 437 ◽  
pp. 505-512
Author(s):  
Yong Shi ◽  
Tong Jiang ◽  
Zai Ming Yang
Keyword(s):  
Parameter Identification ◽  
Electromagnetic Force ◽  
Analytical Models ◽  
Electromagnetic Actuator ◽  
Geometrical Parameters ◽  
Sensitivity Matrix ◽  
Central Difference ◽  
Electromagnetic Actuators ◽  
Error Sensitivity ◽  
Identification Method

To identify parameters of electromagnetic actuators with analytical models, there are problems such as poor model accuracy, multiple physical fields coupling of model, and slow convergence. Based on error sensitivity numerical analysis, a parameter semi-analytical identification method for electromagnetic actuators is proposed. In this article, a diesel engine speed governing electromagnetic actuator is taken as the research object. First, with finite element method, a numerical simulation model of the electromagnetic actuator is established, and sensitivity of main geometrical parameters relative to electromagnetic force is analyzed. Secondly, with theoretical deduction, a difference model of the nominal and measurement electromagnetic force is built, and the electromagnetic actuators geometrical parameter identification formula is gotten. Thirdly, different numerical methods to construct a system error sensitivity matrix are compared, and the compared result is the accuracy of central difference better. Finally, the average static characteristics error of the electromagnetic actuator is reduced from 3.3174 to 1.0182. Therefore, the identification method is verified effective and feasible.

scholarly journals Static Analysis of the Tubular Electromagnetic Linear Actuator with Permanents Magnets

2018 ◽  
Vol 213 (2) ◽  
pp. 83-95 ◽  
Author(s):  
Krzysztof Just ◽  
Paweł Piskur
Keyword(s):  
Finite Element Method ◽  
Static Analysis ◽  
Preliminary Analysis ◽  
Magnetic Circuit ◽  
Electromagnetic Actuator ◽  
Linear Actuator ◽  
Static Characteristics ◽  
Soft Ferromagnetic ◽  
Ferro Magnetic ◽  
Electromagnetic Linear Actuator

Abstract In this paper a results of a static analysis of the tubular linear electromagnetic actuator is presented. The linear actuator consist of two parts: a cylindrical unmovable coils surrounded by a soft ferromagnetic case, and a runner made from sequence of permanent magnet with a soft ferro-magnetic gasket. In the first part of the paper the analytical method was performed for preliminary analysis. In the second part of the paper the more detailed analysis was depicted with using finite element method (FEM). The magnetic circuit shape and impact of selected dimensions on static characteristics is presented. Then the axial and radial electromagnetic force as a function of the runner dimensions were analysed.

Hydraulically Amplified Magnetostrictive Actuator for Active Engine Mounts

2008 ◽  
Author(s):  
Suryarghya Chakrabarti ◽  
Marcelo J. Dapino
Keyword(s):  
Electromagnetic Actuator ◽  
Frequency Bandwidth ◽  
Force Response ◽  
Frequency Range ◽  
Electromagnetic Actuators ◽  
Engine Mounts ◽  
Displacement Response ◽  
Magnetostrictive Actuator ◽  
Active Engine

A bidirectional magnetostrictive actuator with millimeter stroke and a blocked force of ± 22 N has been developed based on a simple hydraulic magnification mechanism. The purpose of the actuator is to replace the electromagnetic actuator in active engine mounts. The Terfenol-D actuator has a flat free displacement response up to 200 Hz and a flat blocked force response over a frequency range of at least 10 to 500 Hz. The actuator promises to deliver a much broader frequency bandwidth than commercial electromagnetic actuators.

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