***UPDATED Strange behavior P4 - Bobs and Weaves in the slightest wind. VIDEO ADDED ***

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Hi all,

You may have seen my other post about the hole in my siding and the poor stability of my P4.

I recalibrated the compass and the IMU and took her out yesterday. I made it perform a POI orbit of my home and while it DID execute a perfect circle on the map during the orbit, (I might just be hyper sensitive to its behavior) it seems to me the bird now has a "bumpy stride" to it. In the slightest wind it seems to almost rock from side to side or corner to corner. An attitude/behavior I normally see in a rapid descent with no other direction motion. Also during a simple hover it does the side to side / corner to corner bumping / rocking, as well as bobbing up and down several inches. As stated in my other thread i've got 7.5 hrs of flight time with this bird, and unless I'm crazy this is not behavior I've ever experienced with it ( again unless I never noticed it befor, and now I'm overly sensitive after hitting the house. Although it was doing this the day it hit the house prior to the crash)

I'll try to get some footage of the anomalous behavior later today.

Pardon the lighting, but as you can see it drifts toward the house , and loses altitude dramatically both occasions I let it try to hold position


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I watched your videos and I'm not quite sure what your talking about with the bobbing and weaving because you seem to be flying it around rather than at a stable hover.

I can however tell you that when I've attempted to fly my P4 in my backyard at night (pitch black) I would get a vertical up and down movement and slight drifting. I would also get a warning that says "ambient light too low". I suspect the erratic behavior of my drone at night is simply because it's far too dark in my backyard for the downward facing sensors to really see the ground at low altitudes. Is it possible your experiencing the same thing? Do you get any warnings?

Just a thought.
 
I wasn't flying it around the entire time. It was dark because that was the quickest I could get the bird out and in the air. Really don't think the VPS should be needed for the stability I've experienced previously from THIS particular bird. I moved the AC around a few times because others have stated that right after takeoff you may sometimes get funky hovering, and to try to re-establish the position with the GPS system.

Video 1 Hover times:
17s - 30s
57s-1:14
2:05-2:23

Video 2 Hover Times:
50s-1:04
1:30-1:50 (Dark too far from cam - Audible comment that I did not direct the bird to drop altitude - Very bad hovering here.)
3.44-4.15 - lotta drift.


Again, I'm not some newbie who doesn't understand his bird. I've got 55 miles and just over 7hrs in the air on 2 different phantoms. I feel like I can expect better from my bird.I will say that the "rocking" from corner to corner / "bumpy" hover is gone.

I'm going to re-calibrate again and will post back if that helps. The stool i calibrated on was leveled with a spirit level and was PERFECT but as we know feces happen so I'll calibrate again. Incidentally would doing a cold calibration have any effect on the bird in this manner? I had refrigerated my bird prior to calibrating as others have said this will help the warm up time.
 
Hey jbrown! Ok I watched your videos again and noticed that your sensor indicator on the display is red in your second video. Now that would indeed indicate some sort of interference with the VPS system or that it's turned off. As stated previously, when I had an issue with ambient light that caused my night time erratic flight, that indicator was also red during that flight. You must be getting some type of warning on takeoff or during flight if your not turning the sensors off yourself. Again I suspect the sensors are not seeing the ground.

Here's a still from your video with the red indicator:
7817300E-97AC-478E-91BE-05BADAD77216_zpsbulff9ai.jpg


And here's a still of my display screen to show you the exact icon that I'm pointing at on your display that's red:
00DB510D-1709-432E-8142-22B1FFA9FAEA_zpswjwuu2u3.jpg


Personally I don't believe it's a calibration issue. I'm somewhat of a noob myself but I'm learning more everyday. Maybe someone here will correct me if my analysis of your problem seems incorrect.

I hope this helps. :)
 
Insufficent light for the VPS simply can't be ruled out with the video you posted. I expect that over featureless concrete at night like that the two VP cameras simply see a uniform gray, and can't register any detail to fix and lock on to.

If the VPS is unavailable, GPS will be used for positioning, but the error in GPS is pretty big, so you'll get all sorts of drift within a 10-15' circle.

Does it do this in daylight? Can you post a video under those conditions, showing the problem?
 
I'm going to try to get a daylight video. I believe it was doing this daylight as well. I thought VPS was only used at lower altitudes anyways. If i recall correctly the bird was rock solid stable at higher altitudes during previous flights. Altitudes where the VPS wouldn't be used. The sensor icon is red because the Obstacle Avoidance is disabled as it makes for a very slow and sluggish P4 in my opinion.

I may be making a mountain out of a molehill though. watching my bird smack the house and land in the bushes rattled me pretty hard.
 
If you have vps disabled the drone isn't going to be rock solid in a hover ad it uses vps for this. So instead it's using less accurate gps. Above 30 feet it uses GPS which isn't as accurate but it's also harder to see the instability at that height.
 
If you have vps disabled the drone isn't going to be rock solid in a hover ad it uses vps for this. So instead it's using less accurate gps. Above 30 feet it uses GPS which isn't as accurate but it's also harder to see the instability at that height.
VPS is enabled, object avoidance is not. I think I'm just tweaked after the crash. Bird looked fine hovering today at low height. And as f3 said, at higher altitude u can't see uber drifting as easily.over probably just never paid such close Attention to the hover before the crash.I'm looking for something to be wrong since the crash. I should be happy. Bird is fine! Btw I had An f2 Honda CBR

Sent from my VS987 using PhantomPilots mobile app
 
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