gon

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Failsafe problem with gps flight mode
« on: May 16, 2017, 04:30:21 pm »
Hi,

I'm having a weird behaviour with failsafe. I'm not sure if this is intentional:

I want my drone to turn off the motors in RC failsafe. So if I turn off my RC controller, the drone should turn off the motors. The default configuration under Input->Failsafe settings already does it. And it works if for example, I have 3 "manual" (stabilized) flight modes (with any stabilization algorithm). But if I put PositionHold (for example) as one of the flight modes, if I turn off the controller, all the propellers start to spin at a very high throttle. Even if the throttle before turning off the controller was 0% and even if the actual flight mode doesn't use the gps.

So, just putting a GPS flight mode, the failsafe behaviour is the inverse as desired, it doesn't matter the current flight mode.

Is this a bug? How can I make the failsafe to be the same independently of the flight modes configured?
(version 16.09)

Thanks!

Re: Failsafe problem with gps flight mode
« Reply #1 on: May 16, 2017, 07:34:42 pm »
It sounds like you are actually using RC failsafe instead of FC failsafe.  In that case, the RC puts out predetermined stick positions and the FC does not even know the RC has a problem.

Look at your Flight Data - System Health when you switch the transmitter off.  If INPUT goes orange, it is in FC failsafe and the FC failsafe settings you selected should be in effect.  If the input stays green, you are using RC failsafe and the FC does not know there is a problem.  Most RC systems (except maybe the least expensive ones) allow you to say "stop sending pulses" when the transmitter is off.  That is what must happen for FC failsafe to be used.

Be aware that when looking at the failsafe switch position from the System page that -1 means stop motors, 0 means use FMS switch position #1, ... 2 means use FMS switch position #3.

You can also look at the Input -> RC Input page to see what the RC controls are doing if you are getting RC failsafe.

gon

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Re: Failsafe problem with gps flight mode
« Reply #2 on: May 17, 2017, 07:04:32 pm »
Hi! Thanks for your tips!

I've finally found what the problem was: As you said, it was a RC failsafe since the System Health monitor had "Input" green when I turn the controller off. And although the receiver puts throttle 0 in failsafe, the switch's correspondent channel outputs a middle value (which is equivalent to the switch position 2). I had PositionHold in that place so it ignores the throttle channel and the motors starts to spin.

I guess I'm gonna solve this by putting a "normal" (stabilized) flight mode in the position 2, and the GPS ones in position 1 and 3.
(Is there another way to solve this?)

Thanks!


Re: Failsafe problem with gps flight mode
« Reply #3 on: May 18, 2017, 05:27:18 am »
Set the throttle channel to -1 (as negative as it will go) will stop the motors if you have mostly default settings.