Please help, inexplicable automatic pitch/yaw signal

Hi all,

My APM powered quadcopter has a persistent pitch signal even when my controls are all in neutral. In other words, upon take off, there is a constant and persistent pitch+yaw signal being sent to the motors. So the effect is a sort of spiral of doom before coming back down to the ground.

I’ve checked and re-checked all calibrations, balance, motors, ESCs, and everything else I could think of. At this point I am out of ideas, which is why I have come to ask for your advice.

Does anyone have any idea what could be causing this unwanted “baseline” signal? More importantly, what parameters could I even look at in order to correct this behavior?

Thank you for your time!

Providing tlogs and data flash logs will help to troubleshoot your issue.

Seconded. A log would help.

Have you checked your motor order?

Sorry, I am new to APM. I’m having trouble downloading the logs, nothing shows up.

However, below is a screenshot of the raw servo output to motor 3 and motor 4 (yes, I have checked, re-checked, and re-re-checked that motors, proprs, and ESCs are all setup correctly). Clearly motor 3 is being given an incorrect signal.

Signal to motor 3, motor 4 (in X configuration) while quad is kept level. I can see with my eyes that motor 3 is spinning slower than the rest.

I’ve tested and eliminated:

  1. Prop
  2. Motor
  3. ESC
  4. PDB
  5. ESC, Accelerometer, Magnetometer, Radio calibration

Somewhere between sensor inputs and sending the signal via PDB to ESC, the motor gets an unwanted signal and I have no idea where to go from here.

I appreciate any help!

Hi all,

I have fixed the issue. Unfortunately, I’m still not sure what was going wrong. What fixed the problem was re-flashing the software onto the flight controller and re-doing all calibrations and parameter settings. My best guess is that perhaps early on in my learning of the systems, I may have changed a parameter without fully understanding the implications.

Regardless, I’ve now had a successful first flight of my custom quad!