Accel Calibration failing if existing accel/gyro parameters are no good

I’ve experienced this twice now. Both times immediately after loading 3.5-RC2. Unsure if it is specific to 3.5-RC2 or a common problem I just never noticed until now. This did not happen when I did the same thing with 3.5-RC1.

  1. Loaded 3.5-RC2, replacing 3DR Solo version of 3.3
  2. Copied a bunch of saved parameters in to include AHRS_TRIM, INS_ACCOFFS, INS_ACCSCAL, and INS_GYROFFS parameters.
  3. Reboot.
  4. HUD showed pitch and roll were way off.
  5. Clicked Calibrate Accel.
  6. Pixhawk ceased responding, lost serial connection, and played dead.
  7. GCS reports calibration failed and had no connection to Pixhawk
  8. Power cycle Pixhawk. Results repeat every time.

After repeating this a few times with the same frustrating result, I went through and wiped out the AHRS_TRIM, INS_ACCOFFS, INS_ACCSCAL, and INS_GYROFFS parameters and calibrated from scratch successfully.

  1. AHRS_TRIM set for zero
  2. INS_ACCOFFS sets for zero
  3. INS_ACCSCAL set for one
  4. INS_GYROFFS set for zero.
  5. Power cycle pixhawk
  6. HUD showed pitch roll way off (more than before)
  7. Clicked Calibrate Accel, Process completed successfully
  8. Clicked Calibrate Level, process completed successfully

I don’t know if this a common thing across Ardupilot or something new with AC3.5. I’ve never experienced this before now.

Hi Matt,

Thanks for the report. Can you post here the values of the relevant parameters you were copying?