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Hey DJI: Easy solution to most crashes

Discussion in 'General Discussion' started by Drestin Black, Oct 2, 2016.

  1. Drestin Black

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    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
     
  2. Drestin Black

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    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.
     
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  3. alokbhargava

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    Let's assume the battery life is 15 minutes. So if connection breaks in first 7.5 minutes, you can expect to get AC back safely else it would die on the return path. I will prefer the current RTH procedure following the shortest path.


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  4. Drestin Black

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    As I said, not intended to replace RTH - have both.

    My idea is intended to get your drone back in connection again.

    I believe that anyone who lost then regained signal wouldn't want to immediately fully abort and just come straight home.

    If you regained signal, wouldn't you want to resume flying whatever you were doing? That's what this would do.

    This is intended to bring the craft back into signal, not intended for a full return flight.


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  5. alokbhargava

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    Our current problem is that there could be an obstruction on the shortest return path. Let's solve that issue by coupling RTH with OAS. I propose that OAS should start increasing the set RTH in case it sees an obstruction until it sees clear path.

    I call this process as ORTH.


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  6. Drestin Black

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    Respectfully, you are completely ignoring my post and threadjacking. This is not a replacement for return to home on the shortest path. That would be your post and idea.

    MY post is about returning to control, getting back to the signal along a SMART path. Instead of making guesses and going up blindly (what if going up causes a collision), my solution would back up along a known, safe path and return to where we had a good signal just moments ago. Reconnect and allow the pilot to decide to resume flying.

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  7. alokbhargava

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    I appreciate your idea and I'm not ignoring your idea. I'm not accepting it as I see that your solution reduces the probability of returning back safely. I'm also not hijacking your thread.

    Whenever someone puts up an idea, we start analyzing it and offer our comments as per our thoughts. We could be totally wrong but that's the way forum works. We debate on the topic and figure out the best for us.

    I compared your solution with what we have currently and thought it would be better if we simply make existing procedure little more intelligent thus increasing the probability of successful flying.

    In case of lost signal for more than 3 seconds, currently there are three options: RTH, hover and land. You are introducing a 4th one similar to reverse mission which I feel will reduce success rate. I may be wrong. I suggested that if we have first option modified with OA, success rate will increase.

    Even in current RTH , one can take back the controls when connection is resumed. But per my experience if it breaks on a short distance, there seems to be a serious problem worth investigation and we should get it back. If signal breaks at a long distance, it's expected and try to get back soon. So in no condition, we would like to wait and follow long route.




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    #7 alokbhargava, Oct 2, 2016
    Last edited: Oct 2, 2016
  8. GMack

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    I dunno.

    Given that my going out course may be zig-zaggy over water, I don't think I want to waste what little battery I might have left when it breaks connection and then try and re-fly the same zig-zaggy course back over the water to get back onto land, unless there was a tracking boat underneath it to catch it. I get nervous enough when the controller starts beeping on low battery. Straight as an arrow home over water and no energy wasted in climbing to a safe clearance altitude either over water.
     
  9. JWH

    JWH

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    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.
     
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  10. GPSMapNut

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    I'd really like to have it as an option but, I'm not holding my breath...
     
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  11. Drestin Black

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    Folks! I guess I should never have mentioned "Return to Home" at all.

    This is not that and doesn't replace it.

    Clear your mind of that function - please try to focus on the scenario.

    You are flying and you go behind a bunch of trees or a building. You lose signal. Are you wanting to throw away the entire flight and go all the way back home or... just back up a little bit, regain signal, then resume flying?

    I'm suggesting a "back up" function. Back out of what got me here.

    Frankly in all my hundreds of flights, I have never wanted to push one button and automatically come straight back home blindly as I grab a beer or go watch tv. I've always flown missions that I took off, flew out, then came back and landed. And almost all of them looked like elongated circles, I didn't come back on the same original line.

    This is. To RTH - talk about your new ideas for new RTH in your own threads. This is back up, regain signal and continue flying yourself. (Though BURGCFY is a bit long)



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  12. Drestin Black

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    Option 3) So, flying along and you lose briefly pass behind a tree or the other side of s large freighter or behind a sail or behind s building. So you land ... in the water or blindly into the ground.

    Option 2) you lose signal, so you just stop and sit there until battery dies doing nothing, then you go into option 3

    Option 1) unit goes up, hopefully doesn't hit anything above, hopefully high enough, the points towards home and flies there in a straight line hopefully not hitting anything. Just seconds after gonna up, it totally regains all contact with the controller ... are you going to ignore that and say, oh well, I'm RTH, guess I gotta keep going. Of course not, you'll say, whew! Glad I'm back in control. Cancel RTH and resume flying.




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  13. alokbhargava

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    I understand you are providing a solution for safety when someone operates NOT in LOS like going behind a tree or a building.

    Cases are different when someone loses signal within LOS.
     
    #13 alokbhargava, Oct 2, 2016
    Last edited: Oct 2, 2016
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  14. Cobs

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    What your suggesting DiB would be best added to the app theyre using, you should maybe email the Litchi creator and put that idea forward, its good thinking and an extra option more advanced users would find useful.
     
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  15. macheung

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    The retrace steps is a great idea that should at least be an option. This would all but eliminate the chance of an obstacle impact on return. In my opinion, this may be a good default if the system detects that there are sufficient battery reserve to return home on a retrace. Otherwise, it should retrace as much as it can until where a direct return becomes necessary due to battery.

    The algo becomes...
    1 - Is this optional featured enabled?
    2 - Is there more than enough battery to do direct RTH with margin?
    3 - if yes, retrace and reevaluate step 2 every few seconds until within 20 meter of home then do RTH. If no, direct RTH.
     
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  16. Traveler

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    I personally can see this as being an excellent option, but I would like to make a minor suggested change. If the signal was strong with a sudden drop off, then it's reasonable to conclude that a reverse course along the recorded path could result in a reestablished connection. Then if it fails to reconnect at a prior know good waypoint, then execute a standard RTH. However if the signal was predictively degrading due to distance, then it would be reasonable to assume that a standard RTH is the logical choice.
    Make a smart RTH even smarter.
    Good idea DB!



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  17. Cobs

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    Ive no idea what code they use but what DiB asks for would be something like this methinks ...

    Check:
    If (self.isFlying && self.RCsignal==lost)
    waitframe // Wait for Lost Signal
    wait 3
    self.Mode==GPS // Engage GPS mode... incase it was in ATTI or Manual.
    thread MessagePilot
    self.moveto self.PreviousTarget
    waitframe
    self.HasReachedTarget -- // Remind itself it "didnt get there" and remove "problem waypoint" from completed waypoint list
    self thread ReConnected
    end

    ReConnected:
    if (self.ReConnected == 1)
    waitframe // Wait For Reconnect
    {
    MessagePilot end
    thread CancelMission
    end
    }
    else
    {
    self thread Check // Go back to first check and remove another waypoint and move back 1 as signal/pilot not re-established, it would keep doing this until there is signal and pilot input or it got back to waypoint 1
    }
    break

    MessagePilot:
    printscreen "Returning To Previous Waypoint"
    printscreen "Please Standby"
    end

    CancelMission:
    printscreen: "RTH?"
    waitframe // Wait For Pilot Input
    if (CancelMission ==1) // Pilot has pressed RTH
    {
    self RTH
    end
    }
    else
    {
    printscreen "Please Check Your Waypoints for Errors"
    printscreen " Or Fly LOS"
    printscreen "You Have Control"
    thread Check // thread back to the first check that detects lost signal
    wait 2
    printscreen end
    end
    }


    You could even get it to drop breadcrumbs (waypoints) at every change of direction so it should always return the way it came ... assuming it still has enough power ... its time they used SmartSolar or MiniArmWindDynamos to recharge in the air here ... infact RF is electricity and can be pulled from thin air. ;)

    Look good to you DiB?
    If (DiB.IsHappy==1)
    {
    Knock yourself out DJI/Litchi etc
    }
    :)

    EDIT: Checked the AndroidSDK seems its Java, shouldnt be too hard to translate ;)
     
    #17 Cobs, Oct 3, 2016
    Last edited: Oct 3, 2016
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  18. konidair

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    Not a bad idea to implement this as an EXTRA option in settings but please fix your misleading title as this option will never fix "most crashes".
    Also keep in mind that "retrace" is not always a safe route(e.g if you are flying behind a moving object that's heading towards your "breadcrumbs" or if you are returning home having low battery and the wind with you and you lose signal you don't want your drone to start flying away from you against the wind).



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  19. Cobs

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    It could be named a breadcrumb (BC) flight (Auto-Runs on takeoff IF the drone isnt in a waypoint mission mode) - just drops waypoints here and there on normal flights and offers you a return via BC or RTH option ... i think is what DiB means.
     
  20. Drestin Black

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    I wrote "most crashes" because I've read as many crash reports as I could both before as way of teaching myself what NOT to do :) and then after I started this idea to see if I was right. What I found was that most crashes are the "whoops, I hit something" type - but a very close 2nd was "Lost signal"

    After lost signal - folks with RTH then encountered one of two things. The drone went high enough that it came up over the top of whatever blocked it's signal in the first place, the signal came back, everyone breathed a sigh of relief, canceled RTH and then resumed the flight.

    My solution sought to both improve on that and act on our normal behaviors. THis is why I keep reminding people, this is not a replacement for or "fix" to RTH - it's still desired and needed by many.

    Logically - if you were flying along and suddenly lost signal. Stop, Back Up Along your existing path - sometimes only a few feet is all that's needed - and the signal would return. At that point, let the pilot decide. I'm venturing a guess that most would say, "Whew, Thanks DiB (haha)!" and then resume with their flight. That's why I am not concerned about straight line return home vs breadcrumbs for power consumption. It's not expected that anyone would let the drone FULLY back up to home. Just back up enough to resume signal and control. At that point, the pilot could resume flying or, what the heck, even kick in the RTH function and straight line it back. The point is; control is restored, safety (both to drone and public) restored and options restored.