Obstacle Avoidance got confused?

Kewlio · Feb 2, 2017

I flew my Mavic close to some tree branches and obstacle avoidance kicked in and seemed to go a little crazy. I take full responsibility for flying it too close to the branches but I did not hit them.

It kept flipping left and right on it's own and would not respond to my commands to descend or reverse. You can see in the video that I am not turning it left/right with the sticks, it is doing that on it's own presumably due to obstacle avoidance, and it continued doing so until finally clipping a branch and falling about 5 feet onto the grass. It sustained no physical damage but apparently the g-force was enough to destroy the internal workings of the gimbal.

My Mavic has been sent back to DJI for assessment and they said it needs a new gimbal/camera for $300+ so I'm using my DJI Care refresh.

I feel as though when DJI miniaturized the gimbal they also miniaturized it's robustness, as I've flown my Autel X-Star into a tree at full speed and only needed to replace a rotor.

I don't know why it would not respond to control while it was doing whatever it was doing.

I'm nervous that if I fly to close to something obstacle avoidance will wig out and not allow me to reverse away or have control.

Anyone experienced this?

CC Rider · Feb 2, 2017

I saw only what you showed us in your video, and, I don't know, man...but I think you were kinda way too close to those branches, closer than I would feel comfortable flying near. OA is a great feature for any drone to have, but I think you have to be realistic about your expectations of what it can do for you. I mean, the Mavic Pro is a $1K usd flying wonder with object avoidance; it's not a $40K usd perfect marvel comprised of the highest tech available.

Even DJI's info warns you not to fly too close to branches and the like, and not to rely on OA in the kind of conditions I think you were flying in. I count on the Mavic's OA, too, but I don't let it replace overall good piloting. Maybe I'm just being conservative - and if so it's only about this, then - but to me you were flying in dicey circumstances and pushed your luck a tad too far. If it was me, I would have had prop guards mounted for that kind of environment. That's what they're made for and why people use them.

tbird5pt0 · Feb 2, 2017

I'd guess since your mavic was "caught" between at least two and probably a handful of branches, as the avoidance system made an adjustment based on the input from one sensor and manuevered the drone to avoid the obstacle it could see, another branch moved out of the blind spot and into view on the other sensor which basically caused the drone to oscillate until it hit one of the branches hard enough to knock it out of the sky.

Kewlio · Feb 2, 2017

I totally agree and do not rely on OA at all. As I said, I also take responsibility for flying it close to the branches (but it did not collide). But in this case I feel like OA did not do what it is intended to do (prevent collision) and actually contributed to my inability to reverse away from the obstacle or have any control whatsoever. So it might as well have not had OA. In fact, if OA was disabled I probably could have reversed away because it was not OA that slowed the Mavic and prevented collision in the first place. There have been many reports of the sensors not behaving as designed.

I don't see how prop guards would have helped since the Mavic was essentially flying on its own. Might have allowed the Mavic to continue it's freakout a little longer but I think the end result would have been the same.

I guess my expectation is too high in that I don't expect to lose control and the drone to whatever it wants should I fly it too close to something.

CC Rider · Feb 2, 2017

I believe you're right about the sensors being open to mishaps. I, too, have seen and read reports of sensor-related crashes. Disabling them while using the drone for the kind of close up work you suggested would make sense, too, as that would totally remove a computer algorithm from the picture and would leave the flight 100- percent dependent upon realtime human eye/controller maneuvers. I do know some folks fly their Mavics indoors with sensors turned off so they retain more control while flying in those conditions. That's why they give you the option to use the sensors or not. It's need or use are dependent upon what you're trying to do.

When flying my Yuneec Typhoon H, I rarely use the provided OA system as I often fly in wooded areas or fly close up to structures, etc., and don't want OA to cause the aircraft to deviate from where I want to put it. Requires more finesse in piloting, like flying without GPS. So far I've always flown my Mavic with sensors ablazing and have been satisfied with the responses it gives me and the protection I sometimes feel more comfortable having. Not a perfect system, but that little machine has not failed to impress me yet.

tbird5pt0 · Feb 2, 2017

Sorry, but I really couldn't resist. After I watched your video, this is the first thing I thought of...

CC Rider · Feb 2, 2017

Ha ha!

I'm sorry, Kewlio, but that IS funny and appropriate!!

jackgarner · Feb 3, 2017

Kewlio said:
I flew my Mavic close to some tree branches and obstacle avoidance kicked in and seemed to go a little crazy. I take full responsibility for flying it too close to the branches but I did not hit them.

It kept flipping left and right on it's own and would not respond to my commands to descend or reverse. You can see in the video that I am not turning it left/right with the sticks, it is doing that on it's own presumably due to obstacle avoidance, and it continued doing so until finally clipping a branch and falling about 5 feet onto the grass. It sustained no physical damage but apparently the g-force was enough to destroy the internal workings of the gimbal.

My Mavic has been sent back to DJI for assessment and they said it needs a new gimbal/camera for $300+ so I'm using my DJI Care refresh.

I feel as though when DJI minitiarized the gimbal they also minitiarized it's robustness, as I've flown my Autel X-Star into a tree at full speed and only needed to replace a rotor.

I don't know why it would not respond to control while it was doing whatever it was doing.

I'm nervous that if I fly to close to something obstacle avoidance will wig out and not allow me to reverse away or have control.

Anyone experienced this?

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I personally don't trust stuff like that to begin with... but hey - my drone is in the same place =P

Could you upload the controller flight log to healthydrones and the .dat file from the drone to something like onedrive or dropbox? I'd be more than happy to try and figure out why it wouldn't respond to stick commands

How to retrieve a .DAT

Kewlio · Feb 3, 2017

jackgarner said:
I personally don't trust stuff like that to begin with... but hey - my drone is in the same place =P

Could you upload the controller flight log to healthydrones and the .dat file from the drone to something like onedrive or dropbox? I'd be more than happy to try and figure out why it wouldn't respond to stick commands

How to retrieve a .DAT

I appreciate that. But honestly I don't see any point in it. I've uploaded my flight logs to DJI, sent them the videos and they didn't seem to care (I'm a small fish, a nobody, and they already have my money). They already have my Mavic and I am using my DJI Care refresh.

It certainly makes me nervous that should I get too close to an object I might not longer have control. Thinking I will probably disable the obstacle avoidance sensors since they seem to be more gimmick than help.

If you want to take a look here is where I'd already uploaded my log to healthy drones -

HealthyDrones.com - Innovative flight data analysis that matters

m0j0 · Feb 7, 2017

Ummm so you flew that close to the branches ... on purpose? Umm I'm sorry but that seems like a reasonably expected outcome. If you absolutely must fly that close to branches, I'm certain the Mavic can't see, turn off the obstacle avoidance and take your chances.

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Kewlio · Feb 8, 2017

m0j0 said:
Ummm so you flew that close to the branches ... on purpose? Umm I'm sorry but that seems like a reasonably expected outcome. If you absolutely must fly that close to branches, I'm certain the Mavic can't see, turn off the obstacle avoidance and take your chances.

Sent from my iPad using Tapatalk

Ummm, interesting analysis. If you watch the video you'll notice the Mavic most certainly saw the branches, contradictory to your statement that " the Mavic can't see" them. It got confused by seeing the branches, not by not seeing them.

I disagree that flying too close to something without colliding with it causing OA to get confused, thereby relinquishing control from the operator, is a reasonably expected outcome. Get too close to something and Mavic goes haywire is reasonable? Ummmmm....... ok.

m0j0 · Feb 8, 2017

The Mavic saw the branches improperly. That was my point. That is why it ended up that way. No worries though please continue to test the limits of the obstacle avoidance system. I myself see value to the community by you doing just that. Please continue to post the videos.

Thanks

m0j0 · Feb 8, 2017

No, get to close to an object that the Mavic is unable to properly identify and expect the performance to be somewhat erratic. That seems like a reasonable outcome.. again though. Continue to fly between tree branches with the OA on. My guess is that you will experience similar outcomes. In other words, I expect failures. Still this is a good learning opportunity for us all. Keep doing it

Kewlio · Feb 8, 2017

First it was "I'm certain the Mavic can't see [the tree branches]" then "The Mavic saw the branches improperly". Which is it?

I encourage you to apply with the CIA, as you appear to have a very bright future as an intelligence analyst. On second thought, belay my last!

m0j0 · Feb 8, 2017

Kewlio said:
First it was "I'm certain the Mavic can't see [the tree branches]" then "The Mavic saw the branches improperly". Which is it?

I encourage you to apply with the CIA, as you appear to have a very bright future as an intelligence analyst. On second thought, belay my last!

Riddle me this riddler. If the OA was able to see the branches wouldn't it have prevented you from flying forward? Of course when you fly a centimeter from the branch it recognizes it... so the answer to your question is BOTH just like I said.. but I stick to my previous statement. Keep flying your Mavic into trees.. I suggest you back up and give it room so you can pick up some speed to really test it.

Your tests have worked out wonderfully so far. Keep pressing ahead and report your research here. Thus far it has been enlightening.. after your tests you can then test the DJI RMA process or the length of time DJI Care refresh turns around a Mavic.

Deuces (mic drop)

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flyboy73 · Feb 8, 2017

Kewlio said:
First it was "I'm certain the Mavic can't see [the tree branches]" then "The Mavic saw the branches improperly". Which is it?

I encourage you to apply with the CIA, as you appear to have a very bright future as an intelligence analyst. On second thought, belay my last!

After watching your video I suggest you don't apply to the CIA either. What did you expect? You were literally asking for what happened.