Hello,
I notice a strange behaviour on my new H frame build. I reused the same APM2.5, version 2.9.1b that I had on my previous quad which worked perfectly.
Normally (that's what I read on the wiki and this how my previous quad behaved) when you program RX failsafe for RTL (Ch3 drops to 900 and triggers failsafe), the behaviour should be:
-when quad is on the ground with motors armed (landed), stabilize mode and throttle down : motors should disarm
What I observe (and this is repeatable) : with quad in the state as described above (landed, armed, throttle at zero), I simulate failsafe by switching off radio => quad takes off like a beast to go to home position, in other words does a RTL !!!!
Is this a new behaviour of 2.9.1b ?
I would like to come back tp the "normal" behaviour , that is "to disarm". Any advice to help me find out what I misconfigured would be welcome.
Extra info : the only difference with my new build vs the previous one, is a 3300uF capacitor I plugged on the APM (on the input rail) to serve as micro UPS for a fraction of a second, should there be a short APM brown out. Would that cause this behaviour ?
Replies
I know this thread is two years old, but it's prominent when googling for this issue. Did OP ever try again without the capacitor?
BTW, I have had this happen while in stabilize with zero throttle and I turn the RX off: Goes immediately to RTL. This was because I had incorrectly set the power off on the receiver to kick me over to RTL, so as soon as the RX lost signal from TX, it would tell the APM to go to RTL. As far as the APM was concerned, there was no fail safe event; it never knew the RX had lost signal. I subsequently set my RX up properly so that when it lost the TX it would kill all signals. The APM then interprets the lack of signals correctly and fires a failsafe event which means only disarm when in stabilize (or acro) with zero throttle OR if not in those, fire RTL (or finish mission when in auto mode).
Of course, it's wildly easier to see all this stuff with Mission Planner loaded, that way you can see the exact values that the APM is getting from the receiver.
Hi Mike,
This is indeed a very old thread...I did not try again recently this scenario with the V3.2.1 firmware and I do not fly anymore with APM boards (only Pixhawk), so I can't tell, sorry.
I agree with Jim, it should disarm and the issue is likely that your throttle is not going to zero or you're not in stabilize or acro mode.
Disarm motors – if you are in stabilize or acro mode and your throttle is zero
RTL – if you have a GPS lock and are at least 2 meters from your home position
LAND – if you have no GPS lock or are within 2 meters of home when the failsafe triggers
Continue with the mission – if you are in AUTO mode and have set the FS_THR_ENABLE parameter to “2″.
What i tried correspond to the first case and should not RTL. Either the wiki is wrong either i have an issue with how my APM failsafe is configured
3300uF capacitor I plugged on the APM (on the input rail) to serve as micro UPS for a fraction of a second, should there be a short APM brown out.
I believe this is very interesting. How long will the capacitor keep alive the APM after Lipo is disconnected or brown out?
Any safe implication you see?
Don't think that this is a new behavior. When you land in stabalize and throttle to zero, the copter does not disarm. If it did it could also do this in flight too with a throttle set to 0 and would take about 5 seconds to rearm. Not good if this happened in flight. I move my throttle to zero in flight all the time when hot dogging around.
So as expected, when the radio is turned off, the copter goes into a RTL mode and climbs to the default RTL altitude.
After landing you will want to insure you are in either stabalize or acro and move the throttle to the lower left and hold it there for about 5 seconds. This will disarm the motors and then you can turn off your radio without it taking off.