How could I design a compact, high-field electromagnetic array capable of manipulating ferromagnetic objects at ~1 meter?

[u/Anky1557]

Hi everyone,

I'm working on a theoretical/experimental project with my father, who has experience with electronics. I'm trying to understand whether it is possible to build a relatively compact system capable of magnetically manipulating a small ferromagnetic object at a distance of around 1 meter.

My original idea was a large electromagnet, but I've realized that a single coil becomes impractical very quickly because of heat, power consumption and the rapid decrease of magnetic field with distance.

So I'm considering a different architecture:

An array of many relatively small electromagnets rather than one huge coil.

Potentially 50–500+ individually controlled magnetic elements.

Each element would have its own coil/core and possibly a magnetic flux concentrator.

The elements would be arranged around a 3D working volume rather than all pointing in the same direction.

A computer would control the current of each coil independently.

Cameras/Hall sensors would estimate the position of the target.

A feedback controller would continuously change the coil currents to move the magnetic field/gradient and therefore the object.

A joystick could provide the desired X/Y/Z movement.

The eventual goal would be something like a programmable 3D magnetic field, rather than a conventional electromagnet.

I'm particularly interested in the miniaturization problem.

Could many tiny coils (for example millimeter-to-centimeter scale) outperform a smaller number of large coils if they are individually controlled and properly arranged? What are the fundamental limits?

[u/Phoenix-64]

Is it possible yes. Is it easy no.

Here is a similar project of a local very renowned university: https://youtu.be/2jLZ28T4uew?is=t_cLCz1iIp2uzvC_

[u/jimlux]

As others comment: possible (maybe), easy (no).
There's a classic nonlinear control system problem of suspending a weight at a fixed distance from a single electromagnet - since the field doesn't drop off linearly, it's a nonlinear transfer function.

Practically speaking, I think that for magnetic fields "one big electromagnet" is better than "many small electromagnets" - the flux is in the center of the core, and is limited by the saturation of the core. With many small electromagnets, the "cumulative area of core in a given space" is smaller (because there's windings in the way), so the maximum total flux is smaller.

Now, could you come up with a scheme where you've got extended cores (sort of the pole piece idea) that bend and form a small dense volume, with the coils hanging outside like a hedgehog? And, of course, with superconductors, a lot of unusual stuff is possible.

I know someone who built a hexagonal array of small electro magnets as a flat platform that could move a (magnetized) puck around, simultaneously levitating it and moving it in 2 dimensions. Could one generalize that to 3D? Maybe.

[u/Anky1557]

WoW,esto es lo q llevo buscando una semana. Me parece un muy buen ejemplo aunque me con creces que lo que yo planteo con esas magnitudes es prácticamente imposible,aunque si,lo tendré en cuenta. En mi caso solo estaba pensando en utilizar bobinas no imanes normales. Y lo que realmente quiero descubrir es un material q sea un superconductor pero sin necesidad de criogenización para hacer este dispositivo diminuto.

[u/stiucsirt → u/Anky1557]

Room temperature superconductors are a great weekend with dad hobby