Landing gear servo glitches when arming

PX4 Autopilot
1

Here’s a new one.

When I arm my drone, as the motors start to rotate, the retract servo makes a quick movement like it wants to retract, then goes back to normal position. I call it a glitch .. a quick movement, then stops. I have checked every possible setting on the RC transmitter, checked all the params in PX4, but nothing shows up as the culprit.

It doesn’t matter if arming with the RC transmitter’s yaw stick or using the QGC slider. The glitch happens both ways leading me to think that some kind of mixing is going on in PX4.

Background: Its a Tarot X6 with Pixhawk 4 running PX4 v1.16.1. This condition never showed up with previous versions, never saw it before. This drone has hundreds of flights and this never happened until upgrading to 1.16.1. Makes me suspicious.

Can anyone jump in with some suggestions or anecdotal experience?

Thanks,

Joe

2

I assume it’s connected over PWM. Make sure that the PWM_DISARM value of the corresponding output is set to the same value as the PWM_MIN/MAX (whichever is correct for the deployed gear state).
You could also check if setting COM_PREARM_MODE to 2 would help.

Beside that a log file would be appreciated. Ideally with logging from boot to see what’s going on at arming.