Looking for troubleshooting help...bad case of the violent wobbles!

ArduCopter
1

Hi All,

I’ve gone and messed something up while fixing something else…I seem to be good at that.

It is a new project, on the maiden test flight I had solid smooth performance for all of the 45 seconds it lasted until I ran into a battery/battery monitor issue.

In tracking down that issue I decided to rewire some of the less tidy connections, I also changed the orientation of the cube/board to improve access to certain I/O ports.

I redid did all the calibration steps after reorientating the board (accelerometer, compass, radio, esc).

Back to the field for another test flight to find I have developed a violent wobble. I don’t think I can do it justice with words so I posted a 30-second video HERE

Have any of you seen this before? Any suggestions on what it could be?

The major change that occurred between smooth flight and the wobble is the change in board orientation. I believe I have configured it correctly in the parameters with AHRS_ORIENTATION set to 6 as the cube is pointed 90 degrees to the left of forward.

Any help will be greatly appreciated.

Cheers,

Pete

The build:

  • Pixhawk 2.1 Black Cube
  • HEX mini carrier board
  • Herelink
  • Here2 GPS/Compass
  • Mauch PL 200 and PL 4 6S BEC
  • T-Motor F60 PROIII motors
  • T-Motor T-5150 props
  • T-Moto F35A ESC’s
  • 14.8V 1500mAh Lipo4S
2

Does the Pitch/roll respond properly in the HUD of Mission Planner? Nevermind, watched the video it wouldn’t fly at all if this was wrong. Post a link to that .bin flight log or at a minimum the parameter file.

3

@dkemxr, thank you for your reply.

Here is a link to the .bin log: https://www.dropbox.com/s/zmptw5zde2943kr/2020-09-11%2017-10-00.bin?dl=0

4

A 5" quad isn’t going to fly well on default parameters. Not sure how it ever did. Start here:
https://ardupilot.org/copter/docs/tuning-process-instructions.html

5

@dkemxr thanks for the link. I got rid of the wobbles and had it holding steady with AltHold for about 10 - 15 seconds then what appears to be a new issue arose and she started to decent regardless of throttle input. As she descended she started to corkscrew.

When I re-armed I noticed #2 motor was not consistent. It spun up in sync with the other 3 then started to falter, then spun back up to match the others then faltered.

I’m new to analyzing logs, any specific values I should look for regarding this behavior?

6

Just post a link to the log.

7

@dkemxr Not sure if this contributed to the issue or was caused by the issue but upon inspection, once I had it on the desk I found the signal lead for the ESC for #2 motor had a loose solder connection.

Unfortunately, I had already deleted the log file prior to your response.

I did try to fly her again on the 22nd. She appears inconsistent to the controls in stabilized mode though my limited flight skills contribute to this I am sure.

When I put her into Altitude Hold all hell breaks loose.

Here is the .bin from that session: https://www.dropbox.com/s/utfsfnkfyla09wh/2020-09-22%2018-22-16.bin?dl=0

I appear to have a large magnetic field issue, I plan on moving the ESC’s out towards the motos to address this.

As before, I appreciate your assistance.