Re: [CAD_CAM_EDM_DRO] typical servo speeds

Graham Stabler wrote:

> I'm enquiring for someone else, they wish to make a system to simulate
> the flapping of a hummingbird wing or something of that nature, rather
> than a fixed mechanism a fully controllable one is desired.
>
> Assuming very low load can a servo motor oscillate at 20hz and if so
> what sort of amplitude might be possible and what sort of
> controllability? Also which servo types are preferred (pcb motors?)

The sky is truly the limit. There are special "moving coil"
motors made for such applications. I have some Yaskawa
super-Minertia motors that are similar. The armature consists
mostly of a coil bobbin on a fiberglass form, with a fixed slug
of iron in the center to complete the magnetic path. The only
thing that moves is the couple grams of copper/fiberglass, so
the inertia is hundreds of times less than a conventional motor.
Maxon also makes motors with very light armatures like this.

Given enough cooling and a powerful enough amplifier, you can
make motors like this accelerate to several thousand RPM and
come to a complete stop again in less than a single revolution.

Printer Motors Inc., Kollmorgen and a few others make disc-type
motors with relatively low inertia. Because of the large disc,
these have more inertia than the "ironless rotor" motors which
have a rotor longer than the diameter.

A real hummingbird, I believe, flaps its wings at about 600 Hz
(or am I thinking about a bumblebee?)

Jon