Lévitation (physique)

La lévitation est le fait, pour un être ou un objet, de se déplacer ou de rester en suspension au-dessus du sol, sous l'effet d'une force qui compense la gravitation, sans contacts physiques solides. Méthodes de lévitation

Le vol (animal, aéronautique), par : **La portance aérostatique (poussée d'Archimède) fait flotter dans l'air des objets qui sont moins denses que celui-ci, comme par exemple les ballons d'hélium, et les aérostats (montgolfière, zeppelin), **La portance aérodynamique maintient des objets en mouvement tels que les animaux volants ou les aérodynes (avions, hélicoptères) au dessus du sol. Ce vol peut être stationnaire (colibri, hélicoptère).
La sustentation électromagnétique, qui utilise un champ magnétique pour la lévitation. Cette technique est utilisée par les trains à sustentation magnétique, **Effet Meissner
La propulsion électrohydrodynamique, qui utilise une haute tension électrique afin de mettre en mouvement un fluide (éventuellement de l'a

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Development of SCARA-Type Haptic Device for Electrostatic Non-Contact Handling System

Benjamin Burns

This paper describes the development of a SCARA-type haptic device, which will be used to assist a human operator in non-contact object handling of silicon wafers using electrostatic levitation. The device has three degrees of freedom, of which only one (vertical) is actively controlled. By utilizing the admittance control paradigm, a high vertical stiffness and a high output force can be achieved. These properties are necessary for the intended application of non-contact object handling to prevent instabilities (induced by the human motion) of the electrostatic levitation system. As the nominal air gap between object and electrostatic levitator is in the order of 350 micrometer, with an allowable position error of about 150 micrometer, instability can easily occur if there is no haptic assistance, especially in the picking up or placing process. The developed SCARA-type haptic device has a mechanical stiffness of 51 N/mm for the vertical direction when it is in the weakest posture, which is sufficient for the non-contact handling task. The design and performance of the haptic device for the active vertical degree of freedom are described in this paper.

2008

Chargement

Polarized Linear Motor Combined With Levitation Actuators Working in a Partial Vacuum Environment — Application to Swissmetro

Christophe Espanet, Pascal Hagmann, Marcel Jufer

Worldwide high speed Maglev (> 400km/h) developments refer to Maglev such as the Japanese JR-Maglev MLX, the German Transrapid and the USA Inductrack Maglev. Other world projects exist such as the Japan HSST (< 300km/h) and the China HTC. The JR-Maglev, the Transrapid and the HSST have reached industrial levels. The Swissmetro Project presents a unique aspect of Maglev: it is designed to work under partial vacuum (< 10kPa) in two tunnels and for high speeds (>400km/h). The authors investigate new possibilities to combine both the propulsion and the levitation. In order to minimize the heat due to the motor levitation and guidance losses, a polarized excitation is proposed. The use of permanent magnet NdFeB for the excitation is still not applied for high speed Maglev, requiring mechanical power greater than 6MW. Such a solution only appears in Urban Rapid Transit Maglev (

2006

Chargement

Passive Guidance Forces of Polarized Linear Motors Combined with Levitation Actuators Working in Partial Vacuum – Application to Swissmetro

Christophe Espanet, Marcel Jufer

Maglev (>400 km/h) refer to Maglev such as the Japanese JR-Maglev MLX, the German Transrapid and the USA Inductrack. The Swissmetro Project, presenting a unique aspect of Maglev, is designed to work under partial vacuum (400 km/h). The authors investigate the combination of the propulsion with the levitation. To minimize the heat due to the iron and copper losses, a polarized excitation is proposed with NdFeB PM for the magnetic way poles. This paper emphasis the determination of the passive guidance forces of the active magnetic way, based on 3D FEM analysis. The possibility, to use these passive forces to guide the vehicle, is presented. This paper describes the issues related to such technical choices.

2006

Chargement

Sustentation électromagnétique

La sustentation électromagnétique est une méthode permettant de faire léviter un objet en le faisant reposer sur un champ magnétique. Les forces magnétiques appliquées à cet objet s'opposent ainsi à

MSE-438: Superconducting electronics: A materials perspective

Introduction to superconducting electronic applications and their material requirements, including the fundamental phenomenology of superconductors. Key applications and their material requirements: a) magnets; b) quantum metrology; c) quantum computation.

ME-474: Numerical flow simulation

This course provides practical experience in the numerical simulation of fluid flows. Numerical methods are presented in the framework of the finite volume method. A simple solver is developed with Matlab, and a commercial software is used for more complex problems.

MICRO-470: Scaling laws & simulations in micro & nanosystems

This class combines an analytical and finite elements modeling (FEM) simulations approach to scaling laws in MEMS/NEMS. The dominant physical effects and scaling effects when downsizing sensors and actuators in microsystems are discussed, across a broad range of actuation principles.