Z Axis Vibrations

As requested I threw up a page with some details of the mounting methodology I use

Anti vibration mounting

Hey thanks for this Mike.
I had pondered O-Rings. Not sure how I would implement them just yet but will give it a think.
I assume your using the native holes on the Pixracer for the O-rings and just attaching them to some pylon… IS this correct and if so any idea on the diameter of the O- Rings you would recommend for the racer…Do you know the hardness number for the o=rings.
I suspect that this would work

And thanks for going the extra mile it’s very much appreciated.
I ordered a pack of rings. Will see what I can do if it’s even possible given the available real estate

As I guessed Mike has had good success with relatively compliant mounts (as have I). This is really the opposite of hard mounting and for many craft I’m not surprised it’s effective even with FC’s with isolated IMU’s.

In fact check this out. This 250 5" with a PixRacer has been a superb flyer for several years now. After trying a few different mount methods this one can’t be beat. It’s super compliant and poses no problems with aggressive flying which is one issue sometimes raised about “too soft” mounts. Perhaps Mr. Steele, or whoever the latest Race Master is, could find fault :wink:

Compliant Mount

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I thought i had a compliant mount yet I have issues. Perhaps I am not compliant enough. Perhaps too hard still, maybe something more flexible.

The ‘O’ rings go through the native amount holes in the Pixracer, yes.

These are the two sizes of ‘O’ rings I purchased but use the smaller one most of the time, with a 1cm distance between hole and standoff they provide just the right amount of tension, and as you saw, with the heavier Cube mount I just use 2 per corner.
Not sure about hardness, have not really seen any references to different hardness for silicone as there is for butyl.

This site just won’t let me upload a pic straight from the camera, some glitch with jpeg sizing.


Sorry about the low res.

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Here is another reply I did with details on vibration mitigation.

I find the upload function on this site a pain in the patutie.
Even files that are smaller then the limit fail when I try to upload. So I open them in MSpaint and use the resize function. I then resize to 25% and save the file under a different name, usually it ends in SM to indicate small and then upload that. This method seems to work just fine and I have no issues with it.
But it’s the only way I can get it to work.
I will give the photos a good going over this evening. Just back from the dentist. AT 18 months of lock down…um…needed a bit of work lol.

Yea I had a cracked tooth that i was able to talk the Dentist 3D cap it even know it was close to the root. I love the Ceric machines. Ok to bad about your vibration and sounds like your set on the soft mounting. wish you luck,. If you had Photoshop all you do is to lower the compression value to 4.

here is a old tip from the cube page from the designer of the Cube [Philip Rowse) “Hard mount your system on a rigid frame. if after doing this, your logs show that you are having vibration issues… then get assistance in designing a correct isolation mount. This will only be needed on the 1% of strange frames or petrol vehicles. always get high speed logging data before attempting to use additional isolation.”

Philip later changed his view on this and I am sure he regretted stating that.

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It’s still on his FB page, in the 6 years making custom drones i never once needed to soft mount unless it was a little 3m tape. but i manually tune my rigs as well.

I will need to ask him about this someday. I stand by my logs and jello free video.

Arducopter on 3" quad sub 250 gr. Omnibus nano V6.0 FC

Low tech damper with acceptable vibe:
https://drive.google.com/file/d/1-U4AZpeMDrMRRLl_derXzfHB2TmAUo3T/view?usp=sharing
Please note that entire carrier box was damped!

Hey Brandon. Yeah teeth argh.
As for the vibes…Not set on soft or hard mounting. I just either need to find out why the vibes are being produced and stop it or come up with a dampener that works…or both lol.
So your input is really appreciated.

See I tend to agree that hard mounting should be the way to go. The thing is I just don’t know whats causing the vibes. While new more expensive props improved things. I still have levels I don’t want to see.
I confess I keep wondering if the gimbal is the problem. So this weekend I am trying the O Ring solution and then I am goign to unplug the gimbal. I am wondering if at speed the gimbal is starting to chatter. I have the same gimbal on another drone and notice it vibrates at times. Something odd about the motors. I am replacing it down the road but right now need to rule it either in or out.

Well that works pretty well. Unfortunately wont’ work in my system. But thank you for the input. Everything is a chance for me to learn more.

cheers

Hey Mike.
So my o-rings came yesterday. I had made a poly carbonate mount for the rings the day before and so got it mounted today.
I had two questions. Did you ever have an o-ring break and do I need 1 or two for the pixracer.

Here is mine on a new build. have a few things to fix but ready to GPS calibrate soon.

So if I am seeing this correctly it’s hard mounted to what appears to be a 3d printed frame or shell.
I wish I knew what was driving my vibes so I could correct it and go hard mount. That was the way the bird was designed. To have the FC hard mounted.

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I was wondering about the legs that could make some vibrations… could you test that?