Hey DJI: Easy solution to most crashes

[Drestin Black]

Sounds like he meant; when signal is lost the firmware interrupts what's up and goes to the appropriate function, depending on which options were set.

I find that a serious omission in the sdk / I'm sure signal strength is one thing you can read. Why not a "controller_connected" = true | false


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[Drestin Black]

In any case, I'd rather this was a DJI solution for everyone, not a separate, paid app. It'll work best in the firmware/base software


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[Cobs]

I edited my previous post ... but if you wish for it to be in the base firmware then it is out of developers hands.

 

[Drestin Black]

Not so much "want" / I think it'll benefit the most people if it's in the base software

 

[Traveler]

That seems incorrect to me considering Litchi is able to over-ride a failsafe using its waypoint missions, if using a breadcrumb mode it should be able to over-ride it happening, best way would be to add another option besides the others, waypoints/orbit/panorama/breadcrumb (or whatever name), as long as its loaded the waypoint info into the mode it should work (once programmed), fly as normal but it drops the breadcrumbs at intervals, just another flight mode/mission basically.

Perhaps he means they cant detect it losing the signal.

Some interesting code in there ...

public static synchronized DJIAircraft getAircraftInstance() {
if (!isAircraftConnected()) return null;
return (DJIAircraft) getProductInstance();

That looks like its checking for a connection, i think thats where to drop a breadcrumb, either every X amount of meters or every course change you get the AircraftInstance and drop a crumb, if a NULL is returned then you initiate the step-back.

Hmm...

@Override
protected int getMiddleBtnTextResourceId() {
return R.string.orientation_mode_home_lock;
}

Wonder if you can remap the homelock/courselock switches to do a different function, i dont ever remember even using those.

I can only offer what they said. However It is a known fact that when you are flying a waypoint mission in Litchi and you lose signal, the flight will continue, but any POI's will not be acted upon. Perhaps this type of limitation is a good example of why they can't make it happen. Additionally, Litchi's waypoint missions always continue if the signal is lost. This makes me wonder if it is by design or just a consequence of a similar limitation.

I hope they will give it more thought and perhaps in doing so they will have a change in their response.

 

[42FrankZ]

. But as you fly from left to right suddenly you go behind a tree to your right. Accidentally.

If you fly behind the tree in this scenario it isn't an accident. You did it purposefully, or you weren't really in control of your aircraft.

Being in control means not flying into spots that you will loose signal.

 

[Drestin Black]

If you fly behind the tree in this scenario it isn't an accident. You did it purposefully, or you weren't really in control of your aircraft.

Being in control means not flying into spots that you will loose signal.

Well, we all try to be perfect. But sometimes we make mistakes and accidentally fly behind something - intentionally or stupidly - and being able to recover would be nice.

I don't get the resistance; it's just one more option to help recover our craft safely and hopefully save the flight and avoid any further damage. Just an option. Folks seem to get "offended" at the idea of changing the "factory way"

Anyway; appreciate all the feedback


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[David Spiteri]

I have been using my P4 for over a year and to be safe I almost always use the Litchi software. When I program a mission , when the mission starts if for any reason the signal is lost (even for minutes), the flight will continue and when the quad will be near the home-point the signal will be back again. I think that using the Litchi software is very safe. I had many flights there it signal is lost for minutes and and the flights were always done.

 

[David Spiteri]

I correct the previous post , it is P3 not P4

 

[Ian Holmes]

Hi guys. I have set my return to home height to 200 feet and it works OK each time I lose connection. As soon as I get line of sight I just regain control. Regards Ian.

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[Matchlock]

Excellent idea, and it appears to be an elegant solution to a very serious situation. Well done sir, and after thinking this over, this is something I would like in my birds.

Well done sir, well done indeed!!

Bud

I've been reading a lot on this forum and others. To me, the most common sources of crashes are: actually hitting something due to pilot error and return to home crashes.

I'd like to address this second category because there is a very easy solution to it, that can be done via software (firmware/app) and would benefit just about everyone. It's so simple I've thought about it a while before posting in case I'm missing something. And DJI Legal, I hereby relinquish any rights to this idea; you are free to implement it without compensation or acknowledgement to me, so long as you do not charge anything extra for this "feature."

Currently we have Return to Home and Smart Return to Home. Thank you, these have no doubt saved many folks in many instances. They have their limitations and problems though. They have to have the right altitude set, and it's done manually, before engagement. And there are limits to how high and also, on systems with Obsticle Avoidance, limitations on what to do should an unexpected obstacle be encountered. Many drones have been lost because RTH crashed into something by taking a as-the-bird-flys straight line back home path.

The solution elements are already already present on all the drones. A record of where the drone has flown and the ability to follow waypoints autonomously. The flight record has a very accurate "breadcrumb" trail and I way points can be programmed and followed, even while out of contact with the controller.

One last comment before I spit out the solution I'm sure many are guessing. In most cases we do not need to fly all the way back home automatically. The RTH function would co-exist with this new one, for times when a straight line, come back to home, is still required. My solution doesn't replace RTH.

The most common times SRTH is used is when the drone loses contact briefly with the controller. RTH kicks in and then just simplistically fly in a straight line back, only offering altitude (and maybe some front OA, if it's on and working) home. What pilots Really want in these instances is control of their craft back so they can resume flying safely and under control.

Back To Contact or BTC is my proposed name. When the drone loses connection, this system would first stop and hover the drone in place for, say, 3 seconds. Signal might resume for various reasons, let's give it a chance (and for the system to queue up what may come next).

If the connection is still missing after 3 seconds; the drone should read back from the flight log the GPS coordinates of the path it just safely flew and replay those waypoints and fly, essentially (if not physically), back along the path that had radio connectivity, it would fly along that path as long as necessary; eventually that would come home to land.

This would be both optional to engage and, of course, can be overridden at any time.

The simple idea: when the drone loses contact with the controller, stop, hover, then fly back along the path it just came, presumable back into signal range where the pilot can decide what to do himself.

Sincerely,
Happy DJI pilot seeking to be safer & happier one,
DiB

 

[hcvvmk]

The simple idea: when the drone loses contact with the controller, stop, hover, then fly back along the path it just came, presumable back into signal range where the pilot can decide what to do himself.



Yes you are absolutely correct, to add on, I have come across events like lost of video signal (dark screen) but with functioning GUI (height, distance etc.) on P3A due to flying too low and being blocked by trees. The golden rule is 'DO NOT PANIC'. It will not stop flying by itself. Just make sure to INCREASE ITS ALTITUDE so that it does not have the risk of hitting any obstacles, and slowly adjust its position back to home based.

Another case I have experienced was hitting the maximum flying distance and time with minimal battery; the drone will return by itself and land on its home and during this time, I was unable to override its auto RTH function, the safest to this scenario is to fly on an open area and prepare to catch the drone in case to avoid it from landing on the water. (yep, i was flying along a coastal area)

Hitting the RTH button is only necessary if signal is lost from the controller..however as soon as the signal is gained back, we should hit the 'x' button to cancel the RTH as mentioned by you.

Cheers!

 

[kphantom]

Shorter version: Keep RTH but make SmartRTH better; do what a pilot really wants. Get communication back and resume safe control of his craft. Upon signal loss, go back along the path just flown, presumably back into controller connection again. Use the flight log for breadcrumbs to set waypoints to follow automatically.

Good idea. The nearest I came to crashing was an RTH initiated due to low battery. If the RTH would just reverse course, it would have been no problem.

 

[NRJ]

I gave you a couple of examples before.
Imagine this scenario: You are filming a train in motion. You and your RC are located on the right side of the train and your drone starts flying at 6ft high, passing in front of the train and filming it's left side...and then you lose signal, your drone backtracks and crashes on the train that's now crossing your breadcrumbs trajectory.
As I have previously written, your idea is good, but nothing is more important than pre-planning your fligts, identifying hazards and simply setting the correct RTH altitude.

Also, IMHO 99% of the time going up and straight home is the safest option. Losing signal/connection with the drone is a scary situation especially if you are flying out of LOS. You don't know if your drone has fallen, if it still flies, if the battery is failing and what kind of other errors it might have during the rest of the flight, so it makes sense to get it back home asap.
I repeat this is my personal opinion but I would like to have a backtrack option available.


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RTH and going up and straight home is good in your scenario. But, what if you are flying under a bridge and you lose signal. Flying straight up may just cause you to lose your bird. Not good in this option. A stop and hover would be better, but then you just drain the battery and it will land in the water. In this bridge scenario, the Back up option works. You can't plan for everything, but the more options you have to get out of it... helps.

 

[NRJ]

If you fly behind the tree in this scenario it isn't an accident. You did it purposefully, or you weren't really in control of your aircraft.

Being in control means not flying into spots that you will loose signal.

I would think that we don't always know where a signal will go bad and not go bad. It also depends on the antenna system on the RC, the type, and power amplified.

 

[42FrankZ]

I would think that we don't always know where a signal will go bad and not go bad. It also depends on the antenna system on the RC, the type, and power amplified.

There could be unknown factors but most of the things that will cause a signal degradation is under the control of the pilot. Using the wrong antenna for the flight, flying behind objects, flying out of VLOS, etc are all things the pilot can control.

 

[skipilot1]

It sounds like all of the above options are needed, depending on the area you are flying. The straight line is needed over water, especially if past the halfway point on the battery. However, in an area where there are trees, buildings, etc. then the "bread crumb" method may be needed. Those options would need to be added to the menu and the proper one selected at the beginning of the flight.

I fail to understand the need for the obstacle issue. Your RTH altitude should always be set above the highest obstacle during your flight.

 

[konidair]

RTH and going up and straight home is good in your scenario. But, what if you are flying under a bridge and you lose signal. Flying straight up may just cause you to lose your bird. Not good in this option. A stop and hover would be better, but then you just drain the battery and it will land in the water. In this bridge scenario, the Back up option works. You can't plan for everything, but the more options you have to get out of it... helps.

Flying under a bridge it's way more likely to lose GPS signal than RC connection, so none of our "solutions" will work. Without a gps signal the drone cannot go home, cannot go back using breadcrumbs and cannot even hover!


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[erkme73]

I really like the OP's idea. But, to be fool-proof, it would have to include altitude breadcrumbs. By that I mean, when retracing the GPS horizontal positions, it must also retrace the altitude history.

As we all know, signal improves with height - so in a scenario where a decrease in altitude caused the loss of signal, simply retracing the last GPS steps without increasing first, well, lights out.

For example, I have property in TN that is right on the edge of the Cumberland Plateau. From my typical launch point, I'm 1000' above the river at the bottom of my property. I can fly my P2V+ out over the river - easily 3-4000' away from my position. But when I fly below the cliff edge, my signal will abruptly drop. I may be 500' BELOW my launch point when RTH kicks in. If a 'backup' feature kicked in, it would have to take into account my previous drop in altitude before trying to unwind the path it took to get there. If not, she's gone.

 

[Cobs]

Flying under a bridge it's way more likely to lose GPS signal than RC connection, so none of our "solutions" will work. Without a gps signal the drone cannot go home, cannot go back using breadcrumbs and cannot even hover!

It would have to be a very wide bridge, ive flown under many bridges and never lost a signal or had it failsafe yet, water is good at reflecting and bouncing signals.

Although Litchi can over-ride a failsafe in its mission mode it seems it cant detect it happening so unless DJI release more source code for developers its not going to happen unless DJI add it themselves.