Instability and Oscillations During and After Autotune Process

ArduCopter
1

Problem Description:

Initial Hover Oscillation Post-Autotune Completion: After completing the autotune process, the drone remains stable initially. However, once the drone reaches a hover state, oscillations start occurring. I attempt to land the drone manually to prevent further instability.
Oscillation During Subsequent Autotune: On the second attempt at autotuning, the drone starts oscillating during the autotune process itself. The instability is observed immediately after starting the autotune sequence, indicating that something during the tuning process is contributing to the oscillations.

image
image940×278 81.1 KB

image
image940×290 90.1 KB

2

Can you supply a link to the .bin log file and a few details about the copter ?
Upload the .bin log file to a file sharing service and copy the link to it and paste in here.

3

Thank you for considering my question. Please find the .bin log file here. https://drive.google.com/drive/folders/1awr4s4Tt0NZ1dYgWMgQF3EA9FCa4tpPI?usp=drive_link
Copter Details:

  • Configuration: Quadcopter (Plus)
  • Motors: MAD M6 260 KV
  • Propeller Size: 24 inches
4

The log has restricted access, set it to “anyone”

What ESCs?

5

ESC : T-Motor Air 40A ESC

6

The Autotune results didnt get saved. Here’s what I would do:

  1. update to latest stable firmware - existing parameters will be preserved
  2. in MissionPlanner, go to Initial Parameters, put in your prop size and battery cell count, also select “suggested” then accept all changes
  3. set the pitch and roll values from autotune (they will be near enough for now), plus some other parameters (see below)
  4. do a test flight in Althold and Loiter to gather more data
ATC_ANG_PIT_P,7.6
ATC_ANG_RLL_P,7.6
ATC_INPUT_TC,0.2
ATC_RAT_PIT_D,0.0031
ATC_RAT_PIT_I,0.088
ATC_RAT_PIT_P,0.088
ATC_RAT_RLL_D,0.0031
ATC_RAT_RLL_I,0.088
ATC_RAT_RLL_P,0.088
INS_HNTCH_ENABLE,1
INS_LOG_BAT_MASK,1
INS_LOG_BAT_OPT,4
LOG_BITMASK,180222

Did you do the ESC calibration process after you set these?

MOT_PWM_MAX,1900
MOT_PWM_MIN,1100

If you didnt, then run the calibration process linked below BEFORE you do the motor tests listed next.

After these changes, reboot the flight controller, go to MissionPlanner Motor Test and check/set these:

MOT_SPIN_ARM
MOT_SPIN_MIN

MOT_SPIN_ARM should be as low as you can get it and all motors would still reliably start up. Add +0.03 to that value and set that new value for MOT_SPIN_MIN

Now do a test in AltHold and Loiter - just do some gentle pitch, roll and yaw. If everything is going OK do some ascent and descent too.
Let’s see that .bin log.

Semi-automatic ESC calibration:
https://ardupilot.org/copter/docs/esc-calibration.html#semi-automatic-esc-by-esc-calibration