You'll need 4 rubber rings ~1.5-2cm diameter, ( used on prop-savers ) and 4 M3x10mm Spacers.
Just squeeze it through the hole:
and lock it on the spacer:
you can use 4 extra spacers and mount the top plate:Good flying to you all :)
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Very interesting. I will have to try this. I am doing some experimentation with different isolation techniques and vibration measurements using the accel data sampled at 50 hz on the bench. I already have found that my vibration grommets allow 3-5 times the amount of vibes that mounting the APM on foam allows. I will add this to the list of experiments. :)
How about very loose strings then, rather than tight rubber rings? That would surely decouple the vibrations, right? ;)
Hahaha, this is so interesting. So different to the dynamics I am used to.
So you do want to introduce lag then, on purpose, because you are more worried about high frequency vibration, yet you are not worried about what the lag will do to the controls. Those gotta be some nasty vibrations then...
The board sits tight, and can't move free of the frame. I'll try to find some copper plate to add some weight to the board, but as is it should work fine. I not seeing any problems so far on indoors testing.
Ian: It's just the opposite. You want as much mass as possible to introduce inertia to decouple the vibration from the frame. A heavier board is better than a light one in this instance. The actual movement of the frame in space is much slower than the induced vibration from an out-of-balance prop. It's the latter that we need to decouple.
Well, this will introduce phase lag for sure. It's possible that if the rubbers are very tense, and given that the autopilots are very light, it works out in the end. Back in the day working on these guys
http://cosmiclog.msnbc.msn.com/_news/2009/10/07/4351338-xombie-rock...
we had to bend over backwards to avoid exactly this type of lag. Bad memories...
Well, I can see how this setup could cause a lot of jostling around of the APM. Depending on how tight the bands are, it could introduce a lag between acceleration of the drone and the APM following suit. This is vibration isolation rather than dampening. Ideally the the APM could be tightly coupled to the drone frame, and just block transmission of frequencies related to motor vibrations vibrations.
Ian: Why? This is exactly the correct way to mount an autopilot, and the way that's recommended by the other autopilot companies, such as Fyetech. It decouples vibrations from the frame and avoids high-frequency aliasing.
Is that mostly for anti-vibration or are the holes on the frame not a good match for the APM2?
I just created an adapter mounting plate to allow those who had mounting holes customized for the APM1 to convert to APM2:
And another special mount for AeroQuad, which uses standard Arduino boards:
That's got to be terrible for dynamics.
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