Yesterday i misjudged my battery and ran out of battery power 7 kms away from my launching point. I tried to land it in a safe park but as soon as plane went close to the ground, it lost RC signal and went into RTL with 100% throttle again.So my try to land in a remote park was unsuccessful and i had to just leave it to its fate. But with a pure chance of luck i found it resting on a tree branch without any damage after 1 day…
Is there any way to stop RTL getting activated on special cases? So please suggest how to do successful remote landings in case of emergency.Thanks.
There isn’t - at least nothing trivial - but you could potentially have
used disarm-on-a-switch to avoid the thing climbing away ('though it would
have attempted to change course and glided around on a heading towards
home in this case)
Yep! Aircraft have been lost by accidentaly switching - some people use
physical protection, some people use fancy transmitter programming to
require two switch movements for the channel to be asserted.
Can i request for a new smarter feature request where arduplane handles this particular situation like i faced but Arduplane handles it better way and where you don’t have to assign a switch to disarm?
Maybe this will work: upload a mission with just 1 way point “LAND” where you want it to land and switch to AUTO. I’ve never tried this and don’t know if it works, but I think its better than an uncontrolled crash.
But of course it requires you have telemetry and use a ground station.
Before flight, search for suitable areas for landing. Set up rally points for that areas. If you see that you have to ditch, then switch to RTL, plane will go to the closest rally point, then start loitering around that point. If you add low voltage cutoff to your motor ESC, then the plane will simply circle down when battery depleted.
I am thinking of accomplishing it with little different way. Please suggest me if there will be any issues with going this route.
Mike @ Dragonlink suggested me this:
I do not set failsafe on Arduplane but instead set it up on my Dragonlink.Its easy to setup “hold custom channel values” by just pressing the menu button for 1 second while flying.So to set it up, I assign RTL on a switch and just fly my plane lets say 300~400 meters away and hit the RTL switch. While the plane returning to the home in RTL mode, I press menu button on dragonlink transmitter to save this custom value for the Rx to present to the flight controller in case of signal loss. Test again if its working properly.
And now in emergency(case of depleted battery),i choose any suitable place to land and switch to FBWA mode and move my throttle down to Zero and press the menu button for 1 second to setup that one time emergency failsafe and i will keep trying glide my plane smoothly to the ground. As soon as plane gets closer to the ground, it would loose signal but it will remain in FBWA mode with zero throttle and glide to the ground in stabilized mode.
Off course i will need to setup my failsafe again after recovering the plane. Do you guys see any issues if i do that? Please suggest. Thanks.
Ninja:
This is a completely different direction you are in right now, but if this is a worry for you going forward, perhaps you should investigate Pitlabs autopilot and OSD system.
I don’t use their autopilots, only their OSD modules because I fly multi-rotors, but I do know enough about their autopilots to have an answer to your problem.
The Pitlabs autopilot can be setup with “ILS” approaches to anywhere. You can select the runway area and landing direction, which can be any field, select the Glideslope - approach angle, etc.
The autopilot can fly these approaches automatically. It’s just a matter of selecting the runway you want to use and a couple of other menu selections, and your plane will go to the approach and fly it down to landing.
In your case, being so far away from home, maybe a couple of runways along or near your route. Your battery gets weak or the winds have changed, so you select the nearest runway, tell the plane to fly there, pack up your gear and go get your plane.
this is how i’ve been doing it on all my setups for years. it might be an unpopular approach, but imho there’s two basically different situations that the chain of failsafe features needs to take care of, which are:
a) the rare case of hardware loss of receiver output signal (brownout, failure etc.)
b) moving out of HF range with an otherwise healthy system
i personally have never been a great fan of mixing both by using FC failsafe only. imho only a hardware issue requires emergency action from the autopilot, whereas a loss of HF connection only imho should exclusively be handled by the RC system, keeping the option to change from the default RTL to a more appropriate mode if the situation requires that.
@glacier051 Thanks for the suggestion. Yes Pitlab OSD is great. In-fact i have a pitlab OSD waiting to be connected to Arduplane in my next build.
@vierfuffzig Thanks Basti for confirming that its not a bad idea to go with this route. I am going to setup failsafe on my dragonlink.In that way i won’t get stuck in rare battery situation that i faced.
What would happen if you set up an approach in FBWA and then disarmed? My control surfaces are still “working” as I’m walking back with my plane after a normal landing so I would guess it should still keep wings level to land if you disarm in the air. Or is there safety I’m forgetting about?
In the mission planner configuration tab in the full parameter tree under batt there is Batt_fs_low_act and the ranges are 0 none 1 rtl 2 land 3 terminate 4 q land. I would think 2 or 3 would accomplish landing the plane. Terminate might be the one because once termination the rtl can’t kick in.
afs TERMINATE is not what you want.
Advanced failsafe options are designed to deliberately crash the aircraft. Termination is where the aircraft deliberately dives into the ground by setting all control surfaces to maximum and throttle is disarmed so as to enter a spin.
I would think land would be optimal but I guess it would come down to how it work in the real world. As long as while in land the rf fs does kick in and try to bring it back. At least in terminate it disarms and doesn’t allow for fs to kick in.