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PX4 / PX4-Autopilot

PX4 Autopilot Software
https://px4.io
BSD 3-Clause "New" or "Revised" License
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MC motors spin when arming VTOL in FW mode #19841

Open jhoexp opened 2 years ago

jhoexp commented 2 years ago

Describe the bug If you want to do a traditional take off on a VTOL quadplane you need to arm in FW mode. I have set the CBRK_VTOLARMING so that arming is allowed when in FW mode, but when I do ARM it, the multicopter motors start too. They just turn at idle doing nothing.

The only workaround I found to avoid this is reducing the VT_IDLE_PWM_MC, so that the MC motors don’t start, but it’s not ideal because this affect the MC mode too, and I want them to idle when armed in MC mode.

To Reproduce Steps to reproduce the behavior:

  1. VTOL Quadplane (Babyshark ariframe);
  2. CBRK_VTOLARMING set to: 159753;
  3. after startup move Transition switch to FW;
  4. Arm the plane;
  5. Plane motor armed and MC motors armed too, spinning at idle (if Idle_pwm is set high enough for them to start up)

Expected behavior Only the FW motor should be armed when arming a VTOL in FW mode, MC motors should remain disarmed.

Log Files and Screenshots Sorry, no log for now.

Drone (please complete the following information):

jhoexp commented 2 years ago

I just want to point out that this behaviour rises some safety concern. On big vtols that have traditional takeoff and landing capabilities, you really need to arm in FW mode to do manual startup/calibration of the combustion engine/s or turbine startup procedures, so it's pretty dangerous if you are around and the MC motors start when thet shouldn't.

jhoexp commented 2 years ago

Tried other VTOL frames to see if this problem was airframe dependent, but nothing changed.

This is creating serious troubles if you need to flight test the Vtol in FW mode before trying a transition, and that's mandatory with big planes. Can someone please verify this and/or bring it to the attention of a developer? It should be an easy fix, given that is very easy to reproduce even at the bench. Thanks!