Unexplained Return to Home triggered...

[cwoav8r]

So... on vacation and taking some video on the creek at our cabin. I have had nothing but trouble with my Galaxy GS9+ crashing during flights...

Secrets to Flying When Phone Disconnects

so I brought an old iPhone 7 and Galaxy S7 to fly with. All my flights with the iPhone were perfect, when I tried my Galaxy S7, not so much. Using my droid phone, I was repositioning for another run up the creek, then it went into RTH for some reason and it started to climb like a homesick angel. Thankfully obstacle avoidance stopped it when it reached the bottom of the canopy. I was in tripod mode, LOS was set to hover because of the dense foliage above, however the RTH altitude was set to 90m (I assumed that if LOS was set to hover it would stay put). I was unable to regain control until I unplugged the phone from the RC and manually flew it back to a safe landing.

I forgot to pack the micro USB cable that came with the RC and I was using a spare I had with me that was plugged into the bottom port of the RC. As I am writing this, the GS7 is plugged into my laptop with the same cable and if I brush against the cable it disconnects and reconnects to the PC, so at this point I blame the cable. But I am still trying to figure out why the attached phone has so much control over the RC. Why, when there is a phone malfunction does my M2P freak out... and is that what triggered the RTH???

Given the area I am flying on the creek with all the trees and dense foliage setting a proper RTH location is pretty much impossible. Obstacle avoidance on the M2P is awesome by the way... just trying to figure out what settings I may be missing in case of LOS, and why I am having phone problems with my droids.

I uploaded the log files to the various viewers but I cant see anything that explains it. Maybe someone can help with figuring this out...

Log file is attached and here is the video... at about the 2:00 minute mark it stops recording, goes to RTH, and recording starts again.

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Thanks!
Ed

 

[Phantomrain.org]

Just looks like you lost connection and it was coming home and than it connected again, time for a smart controller .

Phantomrain.org
Gear to fly your Mavic in the Rain !

 

[Meta4]

then it went into RTH for some reason and it started to climb like a homesick angel. Thankfully obstacle avoidance stopped it when it reached the bottom of the canopy. I was in tripod mode, LOS was set to hover because of the dense foliage above, however the RTH altitude was set to 90m (I assumed that if LOS was set to hover it would stay put).

Here's what your flight data looks like: DJI Flight Log Viewer - PhantomHelp.com
It confirms your Loss of Signal action was set to hover.
Your Mavic was nowhere near low battery level, there's no indication of losing signal either.
Losing the phone would have had no effect on RTH.
Could you have accidentally initiated RTH yourself?

I was unable to regain control until I unplugged the phone from the RC and manually flew it back to a safe landing.

Even without the phone, the simplest and quickest way to cancel any automated flight such as RTH is to switch the flight mode switch out of PGPS and back.

 

[Kilrah]

Just looks like you lost connection and it was coming home and than it connected again, time for a smart controller .

RTH is supposed to trigger on loss of signal between controller and aircraft, the mobile device is optional has nothing to do with it.

 

[cwoav8r]

It confirms your Loss of Signal action was set to hover.

Saw the same data on DJI Flight Log Viewer - PhantomHelp.com

Where do I see that in the log, I am missing it... should I set the altitude lower? Why did it climb?

Losing the phone would have had no effect on RTH.

But that seems to be a recurring theme... with the droids anyway... no control whatsoever until I unplugged.

Could you have accidentally initiated RTH yourself?

Nope, only had thumbs on the sticks... absolutely positive I didn't hit the screen or the RTH button on the RC.

Even without the phone, the simplest and quickest way to cancel any automated flight such as RTH is to switch the flight mode switch out of PGPS and back.

Do you mean to switch from tripod to position and back? I was in tripod mode...

RTH is supposed to trigger on loss of signal between controller and aircraft, the mobile device is optional has nothing to do with it.

The M2P was within 100ft, not sure how I could have suffered LOS... still, every time I have had an issue has been with an android based mobile device. I totally agree that the RC should have full control, but why does my RC have no control when there is an issue until I disconnect the phone? I have duplicated this numerous times, losing confidence in the droids.

 

[Kilrah]

It shouldn't behave that way, but I've also previously had the issue where a bad connection to the phone caused this, it seems that there's a sort of transitional state where the connection is still detected but no data is flowing, the controller thinks the phone is still there and waits on an answer from it, and stops transmitting until that happens. If you disconnect the cable the RC sees there's no phone and stops waiting for it, and everything works fine again.

The problem is not with android devices, but you really need to have a good cable (and be sure the plug in the phone isn't damaged/worn).

 

[sar104]

Nope, only had thumbs on the sticks... absolutely positive I didn't hit the screen or the RTH button on the RC.

I'm afraid your recollection is incorrect. The log records flight action commands, and at 245 seconds you commanded RTH with the RC go home button:

 

[cwoav8r]

Yea, that makes sense. I do think it was more of a problem with the cable. I just wish I knew why my GS9+ was constantly shutting down on me, nothing to do with anything else... just hate that I can't reliably use it to fly because it just randomly shuts off on me.

 

[Meta4]

Where do I see that in the log, I am missing it... should I set the altitude lower? Why did it climb?

It's in the Verbose CSV file.
Under the MC_PARAM.failSafeAction field, it shows Hover for the whole flight.

But that seems to be a recurring theme... with the droids anyway... no control whatsoever until I unplugged.

Your live view had stalled, but you still had full control through the controller.
As mentioned in post #6, it had nothing to do with Android at all.

Do you mean to switch from tripod to position and back? I was in tripod mode...

Once the drone is in RTH, it's no longer in Tripod Mode
Switching to Sport Mode and back would have cancelled the RTH.

The M2P was within 100ft, not sure how I could have suffered LOS

You didn't. But if you did, the drone would have just hovered in place.

still, every time I have had an issue has been with an android based mobile device. I totally agree that the RC should have full control, but why does my RC have no control when there is an issue until I disconnect the phone? I have duplicated this numerous times, losing confidence in the droids.

Explained in post #6

 

[cwoav8r]

I'm afraid your recollection is incorrect. The log records flight action commands, and at 245 seconds you commanded RTH with the RC go home button:

View attachment 77463

The phone had to have commanded that... I was totally watching the M2P at the time and maneuvering with the sticks. I would have to have purposely moved my thumb from the stick and looked at the RC to find, hit, and hold the RTH button. I am 100% positive that I did not hit the RTH button and in fact when it started to climb in RTH mode I did look at the controller and hit the RTH button to cancel which didn't work. Don't get me wrong... I believe you and the data, but I am sure it was the phone, and not me that initiated it.

 

[sar104]

The phone had to have commanded that... I was totally watching the M2P at the time and maneuvering with the sticks. I would have to have purposely moved my thumb from the stick and looked at the RC to find, hit, and hold the RTH button. I am 100% positive that I did not hit the RTH button and in fact when it started to climb in RTH mode I did look at the controller and hit the RTH button to cancel which didn't work. Don't get me wrong... I believe you and the data, but I am sure it was the phone, and not me that initiated it.

The flightAction parameter was RC_OnekeyGoHome. That's the button on the RC, not a command from the phone. If you want to take a look at the DAT file event stream then post the mobile device DAT (FLY051.DAT).

Mobile device DAT file: How to retrieve a V3.DAT from the tablet

 

[cwoav8r]

It's in the Verbose CSV file.
Under the MC_PARAM.failSafeAction field, it shows Hover for the whole flight.

Sorry, just trying to understand... if it was properly set to hover, why did it climb?

Your live view had stalled, but you still had full control through the controller.
As mentioned in post #6, it had nothing to do with Android at all.

When it went to RTH, I had no control with the RC. I am guessing that being in that mode the M2P would not respond to the RC because it was in RTH? The only way I regained control was to disconnect the phone, pressing the RTH button to cancel didn't work.

The flightAction parameter was RC_OnekeyGoHome. That's the button on the RC, not a command from the phone. If you want to take a look at the DAT file event stream then post the mobile device DAT (FLY051.DAT).

I am absolutely sure I didn't press the RTH button... so sure, because I was careful to not specifically set an RTH location (even though it does automatically) and I selected "Hover" for LOS because of the location I was flying... I was very afraid of it trying to RTH with all the overhead obstacles. If the RTH button did get pressed, I have no clue how it could have happened...

Please understand I am not trying to be argumentative, I totally appreciate and respect your help. I'm new to my Mavic and just trying to figure out what is really going on. The FLY051.DAT is attached if you can help with that...

Thanks all!

 

[Meta4]

Sorry, just trying to understand... if it was properly set to hover, why did it climb?

There was no loss of signal or low battery level, which are two of the things that can cause RTH.
So it has to be something else.

When it went to RTH, I had no control with the RC. I am guessing that being in that mode the M2P would not respond to the RC because it was in RTH?

Being in RTH doesn't prevent control of the drone.
Although the drone will continue to RTH (unless cancelled) you still have the ability to vary the altitude etc.

 

[Kilrah]

Sorry, just trying to understand... if it was properly set to hover, why did it climb?

The setting only applies to a loss of RC signal. A manually triggered RTH always does the full RTH procedure.

 

[cwoav8r]

Copy all... so something triggered a manual RTH... still dumbfounded as to how I did it, and don't why when it did I had no control over altitude. Viewing the log, when it went to RTH you can see I input left stick down and it didn't respond.

Thanks guys!
Ed

 

[sar104]

I am absolutely sure I didn't press the RTH button... so sure, because I was careful to not specifically set an RTH location (even though it does automatically) and I selected "Hover" for LOS because of the location I was flying... I was very afraid of it trying to RTH with all the overhead obstacles. If the RTH button did get pressed, I have no clue how it could have happened...

Please understand I am not trying to be argumentative, I totally appreciate and respect your help. I'm new to my Mavic and just trying to figure out what is really going on. The FLY051.DAT is attached if you can help with that...

Thanks all!

No problem - the idea is not to stop you from describing what happened.

The DAT file event stream confirms the txt log - an RC initiated RTH followed by cancelled RTH 10 seconds later:

244.650 : 12947 [L-RC]rc cmd:STD_GO_HOME
254.031 : 13417 [L-RC]rc cmd:STD_EXIT_GOHOME_OR_LANDING

So I'm not sure what to say - the record seems unambiguous. I guess it might we worth checking that the logs are not misreporting, but even an app-requested RTH would require you to have pressed the RTH icon and then confirmed the action. You could do a test flight in which you initiate RTH with the RC, then cancel it, then initiate RTH from the app and cancel it, to compare the log and event stream description for consistency with this flight.

 

[cwoav8r]

Roger that... Thanks sar. I'll do some more flying tomorrow and try it. That last flight screwed me up a bit climbing into the trees, at least the Mavic was smart enough to register the overhead obstacle and stop. BTW what are the "[L-RC]Emergency break. rc vib!" lines in the log... is that the obstacle avoidance registering?

 

[sar104]

Roger that... Thanks sar. I'll do some more flying tomorrow and try it. That last flight screwed me up a bit climbing into the trees, at least the Mavic was smart enough to register the overhead obstacle and stop. BTW what are the "[L-RC]Emergency break. rc vib!" lines in the log... is that the obstacle avoidance registering?

"Emergency break" is the DJI version of "Emergency brake". It's the obstacle avoidance kicking in. I think that "RC vib" refers to the feedback you get from the RC when that happens.