Lost radio signal (or not ?), after RTL Solo landed on the roof.

[pete]

I don't know what happened today, I was busy setting up MPCC and Solo decided to Return Home. The controller was showing "Return Home" so there must have been link between the two and I had video feed.
I was unable to take over the control, Fly button did nothing, Pause did nothing, A button (Fly:manual) nothing, B button (drift mode) nothing. Solo missed the launch point completely and landed on the roof. Very very lucky actually because our roof is really uneven with several layers, one over another and steep. Solo decided to land on the only straight (horizontal) section of the roof (1x2m), narrowly missing a gutter.
I couldn't issue any commands from the controller.
Restarted controller, iPad and finally had the control back but no GPS, launched the Solo in Fly:manual from the roof (just missing the gutter again) and landed. Next flight no problems.

The only thing I can think of is that my controller battery was low (but not completely low) and doesn't explain why I still had video feed and controller was even signaling Return Home (in other words still running). Before I relaunched the Solo from the roof I've put the controller on charge for 5 minutes just in case.

 

[Jubalr]

I agree with your controller low battery assumption. I'm sure Solo would have a FS for that the same as flight battery, and would explain why it would not let you over ride it. It was telling you the it met the low battery threshold for flight but still had enough for telemetry. Like the flight battery when it FS on low battery.

 

[pyrate]

loss of control signal = no control and RTH
not sure how far away you took off from where it landed but GPS is only so accurate

 

[pete]

loss of control signal = no control and RTH
not sure how far away you took off from where it landed but GPS is only so accurate

the horizontal distance from launch point was only about 15m.
but don't understand why I lost the signal, Solo was always in sight and never further than 200m from me.

 

[pete]

I agree with your controller low battery situation. I'm sure Solo would have a FS for that the same as flight battery, and would explain why it would not let you over ride it. It was telling you the it met the low battery threshold for flight but still had enough for telemetry. Like the flight battery when it FS on low battery.

sorry, missed your comment, ok that explains it.
so basically when this happens there is no way to take back the control (even when Solo is almost back to launch point and only 15m away from me)

 

[pyrate]

15 M is a pretty big miss

 

[Jubalr]

sorry, missed your comment, ok that explains it.
so basically when this happens there is no way to take back the control (even when Solo is almost back to launch point and only 15m away from me)

Correct. It;s the same as if you dropped the controller and it was run over. Once it hits that threshold of low controller battery, the best it can do is RTH.

 

[pete]

15 M is a pretty big miss

nothing unusual from my experience, when executing same MPCC several times, no flight is same and sometimes it's out by more than 15m, I had to abort few MPCCs when it was getting too close to a tree or house.

if this is unusual then I wonder if my GPS is out of whack or something, I've ordered the GPS isolation mod from IMP, I wonder if that's gonna improve things

 

[Pedals2Paddles]

Are you guessing on this low controller battery failsafe? I've never heard of such a thing, and I don't think it would be designed like that either.

 

[Jubalr]

Are you guessing on this low controller battery failsafe? I've never heard of such a thing, and I don't think it would be designed like that either.

How else could it be set up? At a given point, the controller output is going to drop due to voltage. Same as turning it off to the receiver (Solo). He also indicate it was charged for a few minutes and was able to fly again.

On a side note; Last summer I purchased the controller extended battery from 3DR. BIG difference in operation time. I sometimes go 3 weeks or more before charging at 50%.

 

[pete]

does this also imply that with lower battery levels on the controller (ie. less than 25%) the strength of the signal is not as good as lets say at controller battery level of 75% ?

 

[Jubalr]

does this also imply that with lower battery levels on the controller (ie. less than 25%) the strength of the signal is not as good as lets say at controller battery level of 75% ?

Like I said. I don't know where the break point is. But like any transmitter there is going to be a point of diminishing returns as far as transmit power. And the Solo (receiver) at some point is going to see it as loss of signal.

 

[pete]

anyway, lesson learnt (or learned ? whatever), I'll be now charging the controller every day, just like the Solo batteries. I was bit lazy with that because the controller usually lasts several days.

 

[Jubalr]

anyway, lesson learnt (or learned ? whatever), I'll be now charging the controller every day, just like the Solo batteries. I was bit lazy with that because the controller usually lasts several days.

Good point. It's always good when a lesson can be learned without a cost. I try not to let the controller get below 50%.

 

[Pedals2Paddles]

The solo has a failsafe for loss of ground control signal. That loss of signal could be due to the battery dying, out of range, etc. But it sounds like your saying you think the controller itself detects it has a low battery, and somehow engages a failsafe mode and then locks the pilot out. Or that the solo detects the controller has a low battery and begins a RTH and ignores the controller. Neither of which I believe.

 

[Pedals2Paddles]

Also, I would count that roof landing as your one and only blessing. That will never happen twice! Wow.

 

[Jubalr]

The solo has a failsafe for loss of ground control signal. That loss of signal could be due to the battery dying, out of range, etc. But it sounds like your saying you think the controller itself detects it has a low battery, and somehow engages a failsafe mode and then locks the pilot out. Or that the solo detects the controller has a low battery and begins a RTH and ignores the controller. Neither of which I believe.

Don't know. Very few cases of people letting their controller get that low. But would be very easy to do especially considering the processor in the controller. Battery voltage gets to X, initiate RTH and save the battery. Alternative; drain to a point of x volts that is lower than can reliably transmit and let Solo RTH. Given the target market and marketing focus at the release of Solo, it would certainly be easy to incorporate. Regardless though, in this case I do believe the controller battery was too low.

 

[pete]

Also, I would count that roof landing as your one and only blessing. That will never happen twice! Wow.

if the roof landing never happens again and instead Solo decides to land 15m on the other side then it's going to land in the swimming pool. I reckon 3DR secretly installed that object avoidance system on my Solo, still cannot believe it chose to land on the only tiny section of the roof that's actually straight.

 

[pete]

Battery voltage gets to X, initiate RTH and save the battery. Alternative; drain to a point of x volts that is lower than can reliably transmit and let Solo RTH.

I have attached bin log to my original post, in case someone can read controller "decision making" from that. I have no idea, only installed APM Planner on my Mac today and I really struggle with this software, seems to me like unfinished product and zero information on how to use it.
(I failed to install Mission Planner - I put WMware on my Mac, installed my old Windows XP Pro, installed Mission Planner but it fails to run) so all I have is this APM Planner for Mac.

 

[Pedals2Paddles]

@Jubalr, I do agree the problem was the controller battery being too low to function properly. I just believe the RTH was initiated by the solo's own failsafe, due to the loss of ground control communication after communication was lost. Not because the controller said "Hey, i'm about to die, so come home now". I do not believe any such controller battery related failsafe exists. Although I'm a little perplexed how he was getting video and telemetry still. It doesn't make much sense.

That said, it certainly isn't a bad idea to have such a failsafe.