I Have inserted the starting pass at a much needed section on Vibration Control in the ArduCopter Wiki and would very much like feedback for corrections or additions from you all.
This is the close coupled mount that I use on my little F330 Flamewheel.
To achieve this plus and minus one tenth G vibration dampening.
In any case, please review the Vibration Control Wiki section under Assembly and give me some (constructive) feedback.
Thank You,
Gary McCray
Comments
Here is a picture of the F450 Oring suspended plate with 3/32 Orings twisted at each corner.
This provides for less vertical board travel, lighter initial hold and faster snubbing.
Corners are counter twisted in relation to adjacent ones to balance motion and prevent board twist.
Corners are also cut back slightly more per Robert Lefebvres suggestion.
Hi Josh, Id lose the Velcro and Zip ties for this.
They represent a vibration transmitting non-compliant restraint.
If you can find a way to secure one or two rubber bands for retaining the board under light to moderate pressure, they are a very good elastic spring.
While they don't have much actual dampening value, they do serve to hold the flight control board firmly in place on the antivibration gel while still permitting necessary differential motion between the vibrating frame and the (hopefully) not vibrating flight control board.
And most vibration dampening materials actually work better under 10 to 20 percent compression.
The rubber bands can isolate while the gel dampens.
This is the technique I will be using for securing the flight control board against assorted gels and dampening media.
Gary, will do, and I'll double check all of my props again as well, but my X/Y accel is almost nothing. I think a key part of the gel is also how securely you ziptie/velcro it to the board, I'll need to play with that. If I can keep it around +/- 7, I'll be happy with such as simple setup that allows me to keep a case on the APM.
Hi Josh, maybe a bit too much gel, you might try cutting 1 pad into quarters and try 1/4 under each corner and see if that doesn't cut vibration a bit.
I have ordered 2 kinds of Align gel, Kyosho Zeal, some 1/2" 30 durometer Sorbothane bumpers and some urethane anti-vibration grommets so I can try various and some "stacked" solutions.
So I'm seeing ~ +/-10 on my accel Z with the gel pads. I'll do a velcro baseline.
Right you are Alberto, should have it this time.
And thank you again.
it's "enable raw" XD
Thank You Alberto, absolutely right, correcting it now.
Intrinsic problem to writer also being proof reader.
there is a mistake in the wiki:
Hi Robert,
Clearance is deceptive in photo, would actually be unlikely to hit a vertical extension post with terminal velocity drop straight into concrete even with the O-rings shown here.
It is almost impossible to push on it hard enough to cause it to have contact.
And I am probably going to end up using Silicone O-rings with thicker cross section than the 1/16" shown here precisely to further limit vertical travel and increase snubbing effect.
Even if the fatter O-rings remove most of the undesirable vertical travel, I think your idea of a (low density) piece of foam under it could have merit in any case and would provide a built in secondary dampening system.
I will certainly give that a try.
Hi Thomas, Aluminum generally won't have a noticeable effect on magnetometer performance, because, although it acts as a magnetic dampener, it's effect relative to Earths magnetic field is negligible.
Steel screws (or plates for that matter) are entirely a different matter and certainly "can" effect a magnetometer depending on position and distance, I know you aren't experiencing any problems, and I use them too.
But if you or anybody else ever does have a problem with them, Nylon, Brass and even non-magnetic stainless steel will usually work just fine.
PS: Really nice Spectrum Analyzer program.
It is proving fairly easy to dampen the primary vibration spectrum for multicopters namely motor/prop vibrations.
The secondary vibrations resulting from non-synchronized motors and props producing resonant high amplitude vibrations of greatly variable frequencies will always be hard to deal with.
It should be noted though that those problems are small inside a conservative flight envelope but increase rapidly as higher performance maneuvering is attempted.
Basically if you are trying to operate a conservatively flown video or camera ship secondary harmonic vibration should remain a small problem. If you are flying high G acrobatics, you are probably less concerned with vibration in any case.
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