I was bored so I thought I would see if my P4P would follow my P4P+. I started the active track with the P4P and it instantly started seesawing. Well needless to say it went to hell in a hand basket in a blink of eye! Has anyone else experinced this. Good thing it was just my other P4P and not somebodys HEAD. I'll post the video.

Zig-Zag... haha


RedHotPoker

Thats what it does and why a minimum distance should be used and why it should be done in a lot more open space than there was ;)

Bashy Posted at 2-12 19:34
Thats what it does and why a minimum distance should be used and why it should be done in a lot more open space than there was ;)

That's what it does!! They should call it active attack not active track. So your telling me that they programmed it to seesaw to get a fix on the subject? It was 13-15 feet away from the other P4P and 15-16 feet off the ground. I'll go back and read the manual but I don't remember it giving specific measurements or a safety buffer zone for such a dangerous seesaw move.  

Edward J Smith Posted at 2-12 20:09
That's what it does!! They should call it active attack not active track. So your telling me that they programmed it to seesaw to get a fix on the subject? It was 13-15 feet away from the other P4P and 15-16 feet off the ground. I'll go back and read the manual but I don't remember it giving specific measurements or a safety buffer zone for such a dangerous seesaw move.

Did you have obstacle avoidance on? I have experienced similar in two conditions. When tracking a moving subject at speeds above 15-20mph it gets out of control laterally from overcompensation. In tight quarters it overcompensates from obstacle avoidance. It looks like it backed off, lost obstacle avoidance and tried to catch up "losing" sight of the other drone.

Edward J Smith Posted at 2-12 20:09
That's what it does!! They should call it active attack not active track. So your telling me that they programmed it to seesaw to get a fix on the subject? It was 13-15 feet away from the other P4P and 15-16 feet off the ground. I'll go back and read the manual but I don't remember it giving specific measurements or a safety buffer zone for such a dangerous seesaw move.

I dont think it does say that but flying within 13-15ft (seems a bit closer to me) is far to close for any safety margin, even worse when the object is so small and so light in colour, CHASCOADMIN reply sounds about spot on...

The truth is I didn't put it Active Track to follow the other drone I thought it would hold it in frame better because of a real slight wind. they were both moving around a little because well that's what they do. Not a lot but enough to not be center in the frame all the time. Had I known that it would have seesawed like that Of course I wouldn't have used it. I have only used it twice before this but it never acted like that. I did have all the optical avoidance enabled. this was at a complete stand still with both drones, and you can see when it starts to track it moves the other drone in center.

I think you were right "It looks like it backed off, lost obstacle avoidance and tried to catch up "losing" sight of the other drone"

Aloha Edward,

     It turns out that Active Track is not able to fix and track on an object as small as another Phantom.  I tried tracking a P3 Advanced (with propguards no less) using my P4 Pro and while the P4 Pro could get a fix, it could not track the P3A.  The P4 Pro would rotate to the P3A but would not move and eventually lost the tracked image.

     One of the Administrators said he had also tried it and was not successful.  When I was trying these tracking experiments, I tried to be above the tracked Phantom so I could get a larger object to track.

     I think the problem with that crash was the two Phantoms have similar sensors in the front and they were facing each other within range of each other.  The signals confused and / or jammed the sensors and you recorded the results.  

     Why were they facing each other?  Tracking usually involves following an object that is not traveling toward the tracker.  As some of the other commenters said, the sensors may have been too close to each other and I would agree.  But then Active Track requires sensors to.  Interesting question.

     Like you, I have been curious about a quad tracking another quad, as noted.  I still have not tried to track my P4 Pro with my Mavic Air yet. With this thread's information, I will be a little more careful just in case.  Mahalo for the information!

Aloha and Drone On!

See-sawing is a typical manifestation of a control that is not properly tuned to the system that it is controlling.  In the controls world its called "hunting."  (over compensating or dead-banding works too)  And/or the control system is not capable of performing the function that is being expected of it.  I have seen it in an improperly tuned PID controls.  Sensors with slow response times or a lot of hysterisis can cause that too.

Anokadrone Posted at 2-13 10:13
See-sawing is a typical manifestation of a control that is not properly tuned to the system that it is controlling.  In the controls world its called "hunting."  (over compensating or dead-banding works too)  And/or the control system is not capable of performing the function that is being expected of it.  I have seen it in an improperly tuned PID controls.  Sensors with slow response times or a lot of hysterisis can cause that too.

OK I understand everything but what a PID control is.

I guess I was asking too much out of my bird. Lesson learned now I'm glad I have care + package. Thought I just totaled a set of props but getting a compass error and it won't calibrate. So off to DJI for my "replacement" bird. Only had 65 hours on her. hope they don't give me one with hundreds on it

Edward J Smith Posted at 2-13 10:33
OK I understand everything but what a PID control is.

PID stands for Proportional, Integral, Derivative.  Its a common control algorithm used in machine controls of all kinds. Been around for years.

You need much more accurate GPS to track safely at that proximity. 3m accuracy needed to be accounted for. If it backed off and tried to go back to it's previous coordinate and missed by 2m... I bet it would track better at a safer distance especially if you could take OBS out of the equation between the two.

CHASCOADMIN Posted at 2-13 16:28
You need much more accurate GPS to track safely at that proximity. 3m accuracy needed to be accounted for. If it backed off and tried to go back to it's previous coordinate and missed by 2m... I bet it would track better at a safer distance especially if you could take OBS out of the equation between the two.

GPS has nothing to do with Active Track, it is optical tracking that is doing the work. It cannot work effectively on small objects.

Damn, Gee, you got ya self a down vote and for what? who've you upset??? I i compensated for it  ;)

Geebax Posted at 2-13 16:59
GPS has nothing to do with Active Track, it is optical tracking that is doing the work. It cannot work effectively on small objects.

So when it loses the track what does it do? Just float into space? Nope. Loss of track and OBS are both backed up.

Bashy Posted at 2-13 21:01
Damn, Gee, you got ya self a down vote and for what? who've you upset??? I i compensated for it  ;)

Me too.....good call.   If it is reverting to GPS when the primary inputs fail, then the system is not accurate enough to compensate.  Floating in space would be a better alternative than taking a wild stab at what it thinks might be the correct position.  Possibly hoping that it will re-establish a viable signal from the the primary inputs.  Bad control strategy.  Could result in a high speed face-plant.

Bashy Posted at 2-13 21:01
Damn, Gee, you got ya self a down vote and for what? who've you upset??? I i compensated for it  ;)

I gave you one back. Yeah, there are all sorts of people who do it for reasons only known to themselves.

CHASCOADMIN Posted at 2-13 23:03
So when it loses the track what does it do? Just float into space? Nope. Loss of track and OBS are both backed up.

Why talk in three letter acronyms, it is not impressing anyone, especially when we have no idea what OBS stands for.


If it loses track of the object it simply stops and hovers where it is, and for that it uses the normal GPS function. If you think it uses GPS to track the object, then please explain how in detailed terms?

Anokadrone Posted at 2-14 05:17
Me too.....good call.   If it is reverting to GPS when the primary inputs fail, then the system is not accurate enough to compensate.  Floating in space would be a better alternative than taking a wild stab at what it thinks might be the correct position.  Possibly hoping that it will re-establish a viable signal from the the primary inputs.  Bad control strategy.  Could result in a high speed face-plant.

Aloha Anoka,

     The quad does not revert to GPS after loosing its track on the target.  It never lost GPS.  Active Track is an attempt at autonomous flight using optical and ultrasound systems.  GPS is a monitoring system at this stage.  If you looked at the flight DATA, you would get GPS coordinates for the whole flight of Active Track.

     The problem is the Vision Positioning and Object Detection (Avoidance) is not accurate enough to detect the target or as I indicated earlier and / or there is interference from the target's own VPS and Ultrasound (they use the same frequency 40 kHz).  You have normal control of the quad when you go into Active Track.  A failed attempt to go into Active Track returns you to normal control.

     Hope this helps!

Aloha and Drone On!

CHASCOADMIN Posted at 2-13 23:03
So when it loses the track what does it do? Just float into space? Nope. Loss of track and OBS are both backed up.

When it loses tracking, i am 79.3% sure it stops and waits for further input

Bashy Posted at 2-14 21:30
When it loses tracking, i am 79.3% sure it stops and waits for further input

That would make way more sense

well I am probably completely wrong, but according to the AI instruction it should go back to the last GPS waypoint in which 3 meter accuracy could be a bad thing. if it is using active track and thinks that the object moved or locks on to something else then you have a problem.

Erm, ya not using waypoints in this mode, all ya doing is visually tracking the subject, waypoints is totally different ;)