P4P Flown with Litchi crashed into tree despite anticollision

Mo of Pocatello · Apr 13, 2017

Today I flew my P4P using Litchi in waypoints mode with anticollision and active anticollision both turned on. (What's Active Anticollision anyway?). I set my first waypoint to be beyond a tree with 2m altitude, The idea is to test the anticollision feature. The P4P slowed down and rang an alarm as it approached the tree at first, but then I think it turned in place on the yaw axis and rammed sideways right into the tree, breaking a couple of rotors. Hope the electronics is OK! Haven't tested it yet.

zander lane · Apr 25, 2017

...active collision avoidance means it will go sideways (...possibly directly into something...like a tree) when it has an obstacle in front of it - I hate this feature as it can instill a false sense of security - maybe if the side sensors actually sensed and avoided (...they only work in tripod mode and one other mode now unfortunately) - until the sensors are better and in EVERY direction, I leave 'em off most times and just try to be careful (...says the man who just destroyed his new p4p by flying sideways into a tree, D'OH!)

smiller · Apr 25, 2017

Some unknown problem was going on as there are several YouTube videos displaying collision avoidance working very well with Litchi, following are but a few:

Mo of Pocatello · Apr 25, 2017

Here's what I think might have happened: when my P4P first approached the tree, it recognized the tree as an obstacle. But then after it turned left, it didn't figure out that the same tree should now be on the right!

smiller · Apr 25, 2017

But why would it have turned left? Even if active avoidance had something to do with it, when that mode is triggered the unit will move sideways but maintain its forward orientation, not yaw left or right, so forward OA should still have been effective.

dmurphynj · Apr 25, 2017

It wasn't Litchi, but my P4P was in Tapfly mode and flew head on right into a tree. Collision avoidance... didn't.

Mo of Pocatello · Apr 25, 2017

Hmmm, wonder what was wrong there?

zander lane · Apr 25, 2017

...with tapfly in free mode there is no OA - was that the situation perhaps?

dmurphynj · Apr 26, 2017

zander lane said:
...with tapfly in free mode there is no OA - was that the situation perhaps?

Sadly, it wasn't in free mode ... this is what DJI had to say verbatim:

"unit succefusly avoided tree's directly infront of it, but crashed away from where the units obstacle avoidance could avoid the one with it crash. Units vision angle is limited, tree was directly infront but got grazed sideways. [Non warranty Repair]"

And here is the video of the crash - not sure I agree with the assessment, but I'm just glad I had DJI Care Refresh.