Hi all. I was trying to figure out alt hold and every time I switched into it the throttle would just drop to arm speed. I realized that it’s because the hover throttle is only about 30%, and this is outside the band that alt hold is initiated when it is switched on (40-60%). I tried changing the MOT_THST_EXPO and it didn’t feel like anything had changed. Also tried fiddling around with the motor thrust min and max parameters and that had some change but not enough. Ideally I would like to scale the throttle control so that when the throttle is at 50% it stay hovering. I appreciate the help! Let me know what other information I can provide that might help.
Seems you’re switching from hovering in a mode like stabilize or acro to altitude hold, which may require that you immediately raise the throttle to 50% in order to hold altitude, especially when tuning is incomplete.
If you already know that hover throttle output is about 30%, set MOT_THST_HOVER to 0.3 (or even better, review a log to determine something close to the actual value) and then follow the hover learn procedure via the documentation, which is as @Allister describes above.
Don’t change MOT_THST_EXPO blindly, as it can have far reaching negative effects if done improperly.