Ener Salinas

On the Design of Ultra-Fast Electromechanical Actuators: A Comprehensive Multi-Physical Simulation Model

In this paper, a simulation of an ultra-fast electromechanical drive was performed by using a two-dimensional axi-symmetric multi-physical finite element model. The aim of this paper is to primarily show that the following model can be used to simulate and design those actuators with good accuracy, secondly, to study the behavior and sensitivity of the system and thirdly, to demonstrate the potential of the model for industrial applications. The simulation model is coupled to a circuit and solves for the electro-magnetic, thermal, and mechanical dynamics utilizing a moving mesh. The actuator under study is composed of a spiral-shaped coil and a disk-shaped 3mm thick copper armature on top. Two numerical studies of such an actuator powered by 2640 J capacitor banks were performed. It is shown that forces up to 38 kN can be achieved in the range of 200 μs. To add credibility, a benchmark prototype was built to validate this experimentally with the use of a high speed camera and image motion analysis.

Continuum gradient-based shape optimization of conducting shields for power frequency magnetic field mitigation

A shape optimization technique for quasistatic field problems has been developed. The optimization is based on computing the continuum sensitivity function by solving an adjoint problem. We show how this technique can be used to compute, in a very efficient way, the optimal shape of a conducting (or ferromagnetic) shielding structure, in order to minimize the magnetic field in the region of interest. A two-dimensional example of shielding three-phase underground cables is considered

Parameter analysis and design framework for magnetic adhesion wall climbing wheeled robot

Some robots need to climb ferromagnetic walls for performing important inspections and evaluations of the material properties of these walls. This paper aims to establish a design framework for magnetically adhering wheeled robots having magnets attached to the base of the robot. The different design parameters influencing the magnetic adhesion include the geometry of the flux concentrator, the variation of the air gap on adhesion and climbing performance in addition to various types of materials for magnetic flux concentration. These parameters shaping adhesion behaviour are simulated numerically using magnetostatic analysis in ANSYS Finite Elements Method (FEM) software. The results are evaluated and a set of rules and procedures are created as a framework that will enable a more efficient design and construction of this type of robots.

On the design of a linear composite magnetic damper

High-voltage direct current (HVdc) breakers are the key components in the realization of multiterminal HVdc grids. In the presence of fault current, these breakers should be able to deliver impulsive forces to swiftly open the metallic contacts. After the acceleration phase, the moving armature should be decelerated using controllable forces to avoid plastically deforming fragile components integrated in the system. In this paper, finite-element method-based simulation models, complimented with small-scale and large-scale experimental prototypes, were utilized to benchmark different damping topologies. It was found that a Halbach-based configuration can deliver a damping force that is almost two and a half times larger than its sequel. Its sequel, composed of vertically stacked oppositely oriented magnets, is easier to assemble and is also capable of generating a considerable damping force. Finally, it has been shown that both these schemes, inserted in a composite tube, have a potential to be used as dampers in HVdc breakers.

Multiphysics modeling and experimental verification of ultra-fast electro-mechanical actuators

In this paper, a multi-physics computational tool has been developed to accurately model and build high performance ultra-fast actuators. The research methodology is based on a finite element method model coupled with a circuit model. Electro- magnetic, thermal, mechanical, and algebraic equations are implemented in Comsol Multiphysics and verified with laboratory experiments of a built prototype. A simplified model is preferred as long as its underlying assumptions hold. However, in the presence of large current and force densities, nonlinearities such as deformations may occur. Such phenomena can only be captured by the use of the developed comprehensive multi-physics simulation model. Although this model is computationally demanding, it was shown to have an accuracy of at least 95% when compared with experiments.

Elasticity Theory for Graphene Membranes

Starting from an atomistic approach we have derived a hierarchy of successively more simplified continuum elasticity descriptions for modeling the mechanical properties of suspended graphene sheets. We find that already for deflections of the order of 0.5 A a theory that correctly accounts for nonlinearities is necessary and that for many purposes a set of coupled Duffing-type equations may be used to accurately describe the dynamics of graphene membranes. The descriptions are validated by applying them to square graphene-based resonators with clamped edges and studying numerically their mechanical responses. Both static and dynamic responses are treated, and we find good agreement with recent experimental findings.

Disseminating mechatronics research results (via science and engineering exhibitions)

To overcome engineering skills shortages in the UK, national science and engineering bodies are actively trying to encourage 11-14 year old pupils to take up Science, Technology, Engineering and Mathematics subjects. One strategy is to bring exciting developments in science and engineering to their attention through science exhibitions. This paper describes the preparation of an exhibit for the Royal Society and the Royal Academy of Engineering to showcase the results of our research in mechatronics engineering that has developed wall and pipe climbing robots and swimming robots for a wide range of industrial inspection tasks. The exhibit is titled “Robot Detectives: Sherlock Holmes meets Spiderman”. It interactively demonstrates wall and pipe climbing robots, swimming robots, magnetic flux concentration principles with levitation rigs, and ultrasound and eddy current techniques for non-destructive testing.

Design and Optimization of Coreless Components Using Admittance Matrix and Efficiently Calculated Sensitivities

This paper presents a novel technique for designing coreless components (inductors and transformers) based on the admittance matrix at quasi-static approximation. In addition, an optimization method based on continuum sensitivity is applied. Efficiency of the design method is shown for inductors that have axisymmetry and carry azimuthal currents. In order to avoid coupling between closely located inductors, a shielding structure is proposed and shape-optimized to confine the magnetic energy

Design of Inductors Using Efficiently-Calculated Sensitivities of the Admittance Matrix

This paper presents a design method for coreless inductors based on admittance matrix, at quasi-static approximation, and an optimization technique based on continuum sensitivity. We show the efficiency of the design method for inductors that have 2D symmetry, in axial plane. In order to avoid coupling between closely located inductors, a conductive shielding structure is proposed and shape-optimized to reduce the mutual coupling