The easiest way to mount APM2 on ArduCopter.

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 :)

Views: 12662

Comment by Ian Garcia on January 24, 2012 at 10:54pm

How about very loose strings then, rather than tight rubber rings? That would surely decouple the vibrations, right? ;)

Comment by Jonathan M on January 24, 2012 at 10:55pm

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. :)

Comment by Jonathan M on January 24, 2012 at 11:01pm

I should rephrase and say "3-5 times the amplitude".  It's hard to sample very high frequency at 50hz :)


Developer
Comment by Max Levine on January 24, 2012 at 11:08pm

@Ian 

APM2 board have very little weight, and it will not be effected by the quads dynamics, 

Actually adding something that will make some little lag in to the frame reaction is a good thing !!!

(not in the code and electronics, but physical suspension) Allowing arms to move (firmly) for just a little before effecting the APM2 sensors, will work like filter. 

there is more to that, but I need to sleep :)          

Comment by Héctor García de Marina on January 25, 2012 at 12:54am

Jonathan,

3-5 times the amplitude mmmm, maybe you are measuring aliasing right? if you are sampling at 50Hz. I am interested in your experiments as I want to try more isolation techniques. Do you mind to share them? :P

Comment by Héctor García de Marina on January 25, 2012 at 1:03am

@Max

All filters (transfer functions) introduces lag (phase delay), and in a closed loop, this lag can lead to instabilty of the closed loop system.

One thing is that the lag introduced don't lead to the instability, which as well depends on your system dynamics and your reference signal (as we have a non-linear system). On the other hand for a control system, your phase margin (for a linear system it measure its robustness) is compromise due to this lag.

It is always a compromise, the lag is never a good companion, but the collateral benefits (i.e. removing high-freq in a low pass filter) could be better.

Comment by Andrew Radford on January 25, 2012 at 2:10am

Given the sample rate on the Gyros, vibration has always been a much bigger problem in this space than lag induced by a suspension mount.

Comment by Anish on January 25, 2012 at 5:58am

have to admit that it is cool :) as @chris pointed out, now joining the rank of commercial flight contraller with "vibration dampening" using advanced patented materials :)

Comment by Anish on January 25, 2012 at 6:06am

@max we have seen some designs incorporating this feature e.g. flexicopter . Would have loved to have someone share some insights to the various mechanical vibration reduction systems ( and may be active vibration reduction :) - way too optimistic)

Comment by Ellison Chan on January 25, 2012 at 8:01am

I still say that Jordi should add some inertial dampeners to the board. ;-)

By phasing the APM2.0 in and out of subspace on every vibration, we would virtually eliminate sensor lag. This is due to  the space time compression that occurs while the APM is the subspace bubble.

Comment

You need to be a member of DIY Drones to add comments!

Join DIY Drones

© 2019   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service