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Old Jul 13, 2012, 08:18 AM
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United States, TX, Richmond
Joined Aug 2010
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Originally Posted by jesolins View Post
R,
Yep. What you have discovered is that changing the weight of a multicopter changes the hover motor/prop RPM which changes that particular multicopter build's vibration frequency and amplitude. Your adding the weight of the Lipos and mounted very tightly to the arms also has a damping effect on the transmitted vibrations. All frames vibrate at different frequencies. If those vibration frequencies are in the resonant ranges of the gyros and particularly the accelerometers,then the data the FCB uses from them can be corrupted by that noise. Some frames and designs use materials that tend to amplify these vibration frequencies and cause higher amplitude harmonics. Multicopter FCBs that have accelerometers are particularly susceptible to the noise these vibrations cause in the the data the FCB uses from the sensors and therefore has to filter the noise to maintain proper level. Gyro only FCBs not so much. Note that the DJI and Sheng Tian modules have the IMUs suspended and weighted to provide the sensors an environment that is somewhat less susceptible to frame vibrations. Therefore those modules are less susceptible to the vibrations some of those plastic type frames tend to modulate. Note that there have been several changes to the plastics in those types of frames since they were introduced and also in the variety of the clone types being sold by various Vendors. YMMV
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Instead of placing the lipo batteries on the sides as you have them in the picture, try attaching them to the bottom plate of the quad. Just use rubberbands for now to see if that helps. I am thinking a lower center of gravity may help like it does on planes.
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Old Jul 13, 2012, 08:22 AM
Tri-Quad-Hexa-Octo-copters!!
United States, TX, San Antonio
Joined Feb 2007
14,258 Posts
R,
There are lots of things you can do to change and reduce the vibration frequency and amplitude that you can experiment with.

1. Balancing motor and props individually and then together is the place to start.

2. Isolate the flight controller as much as possible. Use proven methods such as silicone or Sorbathane grommets and mount the board in a weighted and isolated enclosure. Change the weight of the enclosure to change the way it is affected by your particular builds vibration frequencies.

3. Change total flying weight.

4. Use different frame materials and sizes.

5. Add bracing to frames(not in the prop wash!) at different distances between two or more of the arms..

6. Use the weight of the Lipo(s) to dampen vibrations either on a floating camera mount isolated flight controller mount or main frame or a combination of all.

7. Make sure the ESC and power wires are not transmitting vibrations to the FCB. The wires should never be crossing the FCB or be allowed to touch componets on the board. Having a 180 degree bend before they are attached to the board helps.

8. See the Vibration and balancing solutions section of the
Quadrocopter and Tricopter Info Mega Link Index for more suggestions

Reducing multicopter vibrations to get the best FCB performance for APV requires patient experimentation for the best results. Also as one Gent accurately pointed out, inflight accelerometer and gyro data gathering to show the vibrations during various phases of flight is the correct way to insure you get the best results.

Cheers,
Jim


Quote:
Originally Posted by rizky_p View Post
Thanks for the explanation, i think i understand most of it

Do you have tips on how should i proceed next to dampened the vibration?
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Old Jul 13, 2012, 09:01 AM
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Tasmania, Australia
Joined Aug 2004
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Thanks for the input jesolins. Confirms many of the issues that we see. So regards to vibrations and harmonics, is it possible the best place to mount the control board may be directly to the battery ... being an item of significant mass on a multirotor?? That would help dampen higher frequency vibrations. Isolating the battery (with board attached) with foam would then work well in this case, again because of its mass.
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Old Jul 13, 2012, 10:01 AM
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United States, TX, Richmond
Joined Aug 2010
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Quote:
Originally Posted by kaz1104 View Post
Thanks for the input jesolins. Confirms many of the issues that we see. So regards to vibrations and harmonics, is it possible the best place to mount the control board may be directly to the battery ... being an item of significant mass on a multirotor?? That would help dampen higher frequency vibrations. Isolating the battery (with board attached) with foam would then work well in this case, again because of its mass.
I had a major problem with the jello effect in my videos when I was testing camera mounts for my #16 808 camera. I used an idea from another frame by qiad addict and it completely removed the jello effect so I am wondering if this would work just for dampening vibrations to the controller.

a. Get another DJI plate from gothelirc.com or any vendor. I used the larger plate
b. 4 dampners either from mcmaster.com item #9217K31 or make your own

1. Remove the controller board and cover from the top plate
2. Screw on the dampners onto the plate where the controller was
3. Screw the new plate onto the dampners
4. Put the controller and cover into the new top plate

The dampners basically divide the quad into two sections. A bottom section that contains the arms, motors, esc's, etc. that vibrate and a top section containing your conroller, camera, etc. that may vibrate still but alot less. I have also heard this referred to "dirty" and :clean" sections of a quad.

I made my own dampners using 2 rubber grommets placed between the two plates and held in with a long M3 screw and nut. The screw width is thinner than the center diameter of the grommets I used so they never really touched the screws and it worked. I did purchase the dampners from mcmaster for another frame.
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Old Jul 13, 2012, 10:59 AM
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Canada, ON, Aurora
Joined Oct 2011
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For a Dampner, I just keep the FC in the foam it came in. Perfect protection too, and it's FREE.
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Old Jul 13, 2012, 11:11 AM
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Joined Jun 2011
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Here's a daytime flight video. Loving this board, I just ordered a second one. Very stable and crisp response. Flight begins at about 1min 30 in the video so skip the first 1.5 minute or so if you only want to see some flying.

Best,
Chris

X250 with KK2 board Outdoor flight (5 min 55 sec)
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Old Jul 13, 2012, 11:33 AM
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United States, TX, Richmond
Joined Aug 2010
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Originally Posted by bobepine View Post
Here's a daytime flight video. Loving this board, I just ordered a second one. Very stable and crisp response. Flight begins at about 1min 30 in the video so skip the first 1.5 minute or so if you only want to see some flying.

Best,
Chris

http://youtu.be/WrnuEKfzycY
Very nice flying.
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Old Jul 13, 2012, 12:21 PM
Tri-Quad-Hexa-Octo-copters!!
United States, TX, San Antonio
Joined Feb 2007
14,258 Posts
K,
Yes this has been done successfully in the past. Well...maybe not directly to the Lipo, but attached to the same floating plate that is isolated from the main frame. Experiment and let us know how it works for your particular build You have to keep a flight controller with an accelerometer always level with the prop plane for the self-level to work well. So however you mount the FCB it should always remain in the level mounted and accelerometer calibrated position.
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Quote:
Originally Posted by kaz1104 View Post
Thanks for the input jesolins. Confirms many of the issues that we see. So regards to vibrations and harmonics, is it possible the best place to mount the control board may be directly to the battery ... being an item of significant mass on a multirotor?? That would help dampen higher frequency vibrations. Isolating the battery (with board attached) with foam would then work well in this case, again because of its mass.
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Old Jul 13, 2012, 12:29 PM
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United States, OR, Portland
Joined Apr 2011
385 Posts
Here's a quad I built that had a dirty frame and clean frame, with the camera, KK board and battery all mounted to the clean side (a stiff carbon tube). If the battery wasn't strapped down tight it didn't work very well, but when strapped down REALLY tight... Worked nicely, nice enough to use cheap hk props and prop savers (as a test, I prefer apc props and collet style prop adapters or threaded shafts).

http://fpvlab.com/forums/showthread....olation-method!
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Old Jul 13, 2012, 12:50 PM
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Austria
Joined Jan 2004
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Here is a little video of a KeyCam #11 mounted on a micro quad with kk2

Consider that 2 propeller have been glued back after a crash, and the other 2 are a bit damage .... and no balance at all have been done ...

Hobbyking Turnigy Integrated PCB Plug and Play Micro-Quad (PNP) + KK2 + KeyCam #11 (1 min 12 sec)


To me is looking pretty stable, and I'm also on my 5th fly on a quad copter.

Tchuss

e_lm_70
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Old Jul 13, 2012, 01:01 PM
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United States, MD, Ellicott City
Joined Feb 2010
184 Posts
I LOVE THIS BOARD!!!!! enjoy

kk2 Board micro Quad Part 2 (3 min 36 sec)


KK2 Micro quad part1 (8 min 21 sec)
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Old Jul 13, 2012, 01:04 PM
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Carmichael, CA
Joined Feb 2007
3,449 Posts
Here is one way to damp vibrations:

http://code.google.com/p/arducopter/...ngtheAPM2Board

The tension and thickness of those o-rings could be used to tune out resonance.

A buddy of mine made a "weight box" for the APM2 board on his quad. It's a no more than a small Radio Shack project enclosure, half filled with epoxy, and stuck to the frame with gyro tape. I guess both ideas could be combined, then you wouldn't have to be so good at balancing props, LOL!

Kev

[edit: Great flying, and nice video guys! Bobepine yours is very well tuned. e_lm_70, did that oscillation pop up since the damaged props, or has it always been? MIDNCOCO, nice display of the SL abilities, and excellent review overall!]
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Old Jul 13, 2012, 03:33 PM
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Canada, ON, Newmarket
Joined Nov 2006
2,228 Posts
I got a GLB X525 for my first quad copter. It had a Multi Wii board and the programmer was defective. Well waiting for a replacement programmer I got the KK2 thinking it would be better for me being a noob to these. I have the KK2 in it but I'm having some issues with it. The motors keep pulsing and I don't know why? Any help is appreciated.

X525-KK2.3GP (0 min 15 sec)
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Old Jul 13, 2012, 04:24 PM
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United States, OR, Portland
Joined Apr 2011
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Quote:
Originally Posted by davecrash View Post
I got a GLB X525 for my first quad copter. It had a Multi Wii board and the programmer was defective. Well waiting for a replacement programmer I got the KK2 thinking it would be better for me being a noob to these. I have the KK2 in it but I'm having some issues with it. The motors keep pulsing and I don't know why? Any help is appreciated.

http://youtu.be/ZrxiOvNqIQE
Have you gotten it out of ground effect yet? Close to the ground its going to bump around a bit until you get high enough to get out of ground effect.
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Old Jul 13, 2012, 04:36 PM
Tri-Quad-Hexa-Octo-copters!!
United States, TX, San Antonio
Joined Feb 2007
14,258 Posts
D,
Recheck your motor servo wires are going to the correct arms and that the motors and props are rotating in the correct directions per the manual. Those are the things that normally cause that pulsing which would become a flip if you inappropriately added more power.
Cheers,
Jim
Quadrocopter and Tricopter Info Mega Link Index
Quote:
Originally Posted by davecrash View Post
I got a GLB X525 for my first quad copter. It had a Multi Wii board and the programmer was defective. Well waiting for a replacement programmer I got the KK2 thinking it would be better for me being a noob to these. I have the KK2 in it but I'm having some issues with it. The motors keep pulsing and I don't know why? Any help is appreciated.

http://youtu.be/ZrxiOvNqIQE
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