For a VTOL, I’m trying to get the motors to spin when armed (at very low speeds, just to check if the motors are spinning correctly and in the correct direction before taking off).
I’ve followed the documentation posted here to create a custom mixer (custom.main.mix) and a script in init.d/airframes (created in ROMFS/px4fmu_common/…) that loads the mixer by calling set MIXER custom.
Since it is for testing purposes, only the multirotor part of the VTOL is mixed right now. Below is the multirotor part of the mixer.
R: 4+ 10000 10000 10000 0
In this script in init.d/airframes, I also call param set PWM_MIN1 1100 (also for channel 2, 3 and 4). If I then look in parameters in QGroundControl, min pwm is set to 1100 for those channels. If I then arm, the pwm is set to 900. The other lines in the script are executed (battery cells are set correctly etc).
I can use Idle speed to bump it up to 1120, but that seems weird to me. Why include the PWM_MIN if it doesn’t change anything?
I don’t think this should depend on ESC calibration. The PWM that is being sent (checked with oscilloscope) is 900 us instead of what is specified with PWM_MIN
Hi @Etruscian,
It’s best to leave the PWM_MIN at default. To specify at what PWM the motors are of a VTOL in MC mode with minimal throttle, you can change VT_IDLE_PWM_MC .
If you still have issues it would be best if you could share a log file, then we can help you better.