The magnet trick: New invention makes vibrations disappear – TechnoNews

When all the pieces shakes, precision is normally inconceivable—everyone who has ever tried to take a photograph with shaky palms or make handwritten notes on a bumpy bus journey is aware of that. With technical precision measurements, even a lot smaller vibrations are a significant drawback, for instance, with high-performance microscopes or exactly aligned telescope mirrors. Even the smallest vibrations, which aren’t even perceptible to people, can render the measurement outcome unusable.

A brand new sort of vibration damping know-how has now been invented at Tu Wien that solves such issues in an uncommon approach: electropermanent magnets are used. These are magnets that, like strange everlasting magnets, keep their magnetism completely with out the necessity for an influence provide, however that are additionally fitted with a coil in order that their magnetization could be modified extraordinarily quick utilizing {an electrical} pulse. This makes it potential, for instance, to actively suppress vibrations in mirrors in massive telescopes and thus dramatically improve their efficiency.

The examine is printed within the journal IEEE Transactions on Industrial Electronics.

A floating platform with nanometer precision

The vibration damping system at Tu Wien consists of a completely mounted base and a free-floating platform above it. The platform is suspended within the air, stored in place by robust magnetic forces. A number of electromagnetic actuators can then fine-tune the place of the platform with excessive precision in fractions of a second—even when a load of a number of kilograms is mounted on this platform.

“In sensitive applications, such as the positioning of mirror segments, the position of this platform must be kept stable to within a few tens of nanometers,” says Prof. Ernst Csencsics from the Institute of Automation and Management Expertise at Tu Wien.

“This is only possible if you can compensate for even tiny ground vibrations, such as those that occur when someone walks past outside the laboratory, or those caused by normal building vibrations.”

The place of the platform should subsequently be measured extraordinarily precisely and any motion have to be counteracted instantly. This makes it potential to suppress vibrations very effectively, particularly low-frequency vibrations, that are normally an issue in such purposes.

Electromagnets want fixed energy

“Electromagnets are usually used for such active vibration damping,” explains Institute Director Prof Georg Schitter. “A current flows through coils in a magnetic field, and depending on how strong this current is, different forces can be generated. This works very quickly and precisely.”

One main drawback of this know-how, nevertheless, is that the present should movement constantly, in any other case the magnetic forces disappear immediately. A everlasting magnet, alternatively, can keep its magnetic properties for any size of time with none exterior vitality provide—as soon as it has been magnetized by a really robust magnetic area.

On a regular basis everlasting magnets, as we all know them from magnetic boards or fridge magnets, are additionally created on this approach: You want an appropriate, magnetizable materials and expose it to a robust magnetic area as soon as. This creates a magnetic order within the materials, inflicting it to stay magnetic completely.

Remagnetizing everlasting magnets in a focused method

The researchers have now succeeded in combining the benefits of electromagnets and everlasting magnets in vibration damping utilizing a so-called electropermanent magnet.

“This is a permanent magnet that is also fitted with a coil,” says Csencsics.

So long as the power of the everlasting magnet is within the appropriate vary, it doesn’t require any energy and the hovering platform is held in place. Solely small corrective measures by the actuators are essential to compensate for vibrations.

Nevertheless, if the power of the everlasting magnet is not acceptable, for instance as a result of the burden resting on the hovering platform has modified or as a result of it must be tilted, then extra drastic strategies are used: A brief, robust present pulse is distributed via the coil, creating a really robust magnetic area for a second and thus additionally altering the magnetization of the everlasting magnet.

By deciding on the correct magnetic pulse power, the everlasting magnet could be set to a brand new working level, at which it then stays fixed once more with out the necessity for an vitality provide.

Working prototype, patent pending

This management could be automated: The system routinely acknowledges whether or not it’s nonetheless near the specified working level or whether or not remagnetization is critical.

“We have developed the necessary control technology over the last two years and it is already working very well,” says Csencsics. The invention has already been patented with the assist of Tu Wien’s analysis and switch assist group.

“With our prototype, we have shown that extremely precise and energy-saving vibration suppression is possible,” says Schitter.

“The technology would be perfect for large telescopes, for example, which consist of several mirror segments. The telescope must be able to be aligned to different areas of the sky, and the mirrors must then be aligned with high precision and kept stable in every position. This is exactly what our technology would be ideal for.”

In precept, nevertheless, the know-how of electro-permanent magnet vibration damping might in fact even be utilized to different areas, such because the precision manufacturing of semiconductor chips and huge high-quality optics, adaptive actuators or laboratory-based precision measurement know-how.

“Wherever you need the highest possible precision that could be disturbed by vibrations, our technology is an interesting solution,” the researchers say.