Dreaded Vibrations! - Please help, giving up!

So I am using a pixhawk on a quad and it works great if I just let it hover, POS hold is rock solid and so is alt hold. But in AltHold or POS HOLD as soon as I give it some forward momentum and then back or just sharp turns it instantly goes 100% throttle until I switch it to Stab and I have to let it fall for a bit until its back at the level it started at at.

Now I know it's vibrations because I review my logs and the Z, x y,  accel is great until it it puts out more throttle then it goes crazy and thats when alt hold misbehaves. I tried EKF and issue still happens, I tried really thin "airy" foam but compressed with the same foam on top (made a pixhawk sandwhich), my latest was moongel and I did 2 peices at each end and used its standard pre cut size. I was thinking of doing 2 layers next...

So I am trying to find out which motor, prop is the issue but I have gone through a number of props (I just have been flying normally and not using RTL or alt hold (RTL uses ALT hold so if it goes into RTL I lose my quad in the sky forever)

I switched out a motor since it sounded funny on the bench although I felt minimal vibrations when testing with out props. It just has a "hum" vibration, hard to explain. (this is 4 all 4 motors)

I balanced the props and tested them on the quad and they all produced similar vibes and nothing major

I bought new arms in case some were twisted or something and still same issue.

Tightened all screws

I put it in Poshold and just watched the props for a couple minutes in hover and they looked fine

Frame: Aphid x450 (Uses f450 arms)

Sunnysky xx2212 980kv, 3S, 10x4.5sf plastic.

You need to be a member of diydrones to add comments!

Join diydrones

Email me when people reply –

Replies

  • So an update,

    Purchased new sunnysky motors with t prop adapter, new frame, and new carbon props, seems to fly really well now, hammering the sticks trying to cause massive vibrations and its still good. I think it was motors that caused the issue.

    I am having an issue and I beleive it may be becase of of the moongel, I am losing yaw lock, I have not done compassmot yet but thats the plan later today. Just wanted to ask if anyone had similar issues with moongel?

  • hi, as you say the root of it all is vibration in the motors - so careful balancing will help a lot.

    but for the vibration thats left (theres always some), ive found that stiffer foams work much better.  if you can, get your APM on a board with as much weight as possible (ESCs? battery? radio?) and isolate that as a single block.  in any case i have had much success with neoprene - both a sheet i bought in a local rc shop as "radio mounting foam" and a chopped up mouse mat.  recently i am trying 1/4" sorbothane which is also working very very well.

    one more thing .. i have a TBS discovery flying with the same motors and found that there is more z axis vibration in the centre of the plates between the arms.  mounting at the edge of the plates seems better.

    • Thank you,

      I bought 4 new SS x2212, new frame, new carbon props, I was very rough with the first quadcopter so maybe the motors got a little to much abuse.

This reply was deleted.

Activity

DIY Robocars via Twitter
RT @a1k0n: @DanielChiaJH @diyrobocars @circuitlaunch Here's my car's view of that race. About 8.4 second lap times for laps 2 and 3... both…
yesterday
DIY Robocars via Twitter
RT @DanielChiaJH: Great racing against @a1k0n today at @diyrobocars! Pretty cool to both break sun-9s at the track today I think I got very…
Sunday
DIY Robocars via Twitter
Broadcasting the @circuitlaunch race live now at https://m.twitch.tv/diyrobocars Races begin around 2:00pm PT
Saturday
DIY Robocars via Twitter
RT @a1k0n: ran a huge number of hyperparameter tuning experiments yesterday; now I can train a new policy, far with better quality, in 15 m…
Saturday
DIY Robocars via Twitter
RT @a1k0n: Did I get rid of hand-tuned parameters? Yes. Am I still hand-tuning more parameters? Also yes. I have a few knobs to address the…
Sep 26
DIY Robocars via Twitter
RT @a1k0n: I'm not going to spoil it, but (after charging the battery) this works way better than it has any right to. The car is now faste…
Sep 26
DIY Robocars via Twitter
RT @a1k0n: Decided to just see what happens if I run the sim-trained neural net on the car, with some safety rails around max throttle slew…
Sep 26
DIY Robocars via Twitter
Sep 24
DIY Robocars via Twitter
RT @SmallpixelCar: @a1k0n @diyrobocars I learned from this. This is my speed profile. Looks like I am too conservative on the right side of…
Sep 24
DIY Robocars via Twitter
RT @a1k0n: @SmallpixelCar @diyrobocars Dot color is speed; brighter is faster. Yeah, it has less room to explore in the tighter part, and t…
Sep 24
DIY Robocars via Twitter
RT @a1k0n: I'm gonna try to do proper offline reinforcement learning for @diyrobocars and throw away all my manual parameter tuning for the…
Sep 23
DIY Robocars via Twitter
RT @circuitlaunch: DIY Robocars & Brazilian BBQ - Sat 10/1. Our track combines hairpin curves with an intersection for max danger. Take tha…
Sep 22
DIY Robocars via Twitter
RT @SmallpixelCar: Had an great test today on @RAMS_RC_Club track. However the car starts to drift at 40mph. Some experts recommended to ch…
Sep 11
DIY Robocars via Twitter
RT @gclue_akira: 世界最速 チームtamiyaのaiカー https://t.co/1Qq2zOeftG
Sep 10
DIY Robocars via Twitter
RT @DanielChiaJH: Always a good time working on my @diyrobocars car at @circuitlaunch. Still got some work to do if I’m to beat @a1k0n howe…
Sep 10
DIY Robocars via Twitter
RT @SmallpixelCar: My new speed profile for @RAMS_RC_Club track https://t.co/RtLb7TcgIJ
Sep 10
More…