Unstable hovering, "wobbling"

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Hello (please excuse my poor English),

I am flying a P4pro since a few days. It is already the second "replacement" drone, thee other two had to be returned because of several problems. Before the P4pro I had seveal kit drones, then an Yuneec Typhoon H and an Phantom 4 (non-Pro).

The first P4pro I received had a problem with "hovering", it hovered VERY unstable, massive "wobbling" back-and forth and left-to-right, about four times a second. The sound was very strange, like "Wow-wow-wow..."
It also had a very soft camera lens.

I returned it and got another P4pro. This drone hovered stable and had a sharp lens but it could not hold the yaw position of the camera gimbal; after every turn the gimbal yaw was "creeping" very slow for about 30 seconds from right to left, turning about 10-15% of the horizonal viewing angle.

I returned this P4pro too and got the third.
First flights were perfect, no "wobbling", no "gimbal creeping", and the centering of the camera lens was clearly the best of the three.
But a fed days later, when the drone hovered high over me, I again heard the "Wow-wow-wow" propeller noise, and after reducing the height, a VERY strong "wobble" when hovering was visible.
The drone also reacted "sluggish" and "pardox" to some steering commands when "wobbling". Trying to fly forward resulted in a quick left-then-right yaw turn of the drone at the start, leading to a light "zig-zag" flying.

I immediately landed and re-calibrated compass and IMU.
After that, the drone flew without "wobbling" and reacted precise to the steering commands.
But only for a few minutes, then the "wobble of death" was back!
I tried to land, but the drone was almost out of control, at ~7 meters it crashed into a tree, ripped off the camera at the gimbal yaw arm and came down.

thanks to the low altitude and soft ground, no further damage of the "drone core" itself, not even a greater scratch or so. "Only" the gimbal yaw arm and the black ribbon cable of the gimbal are broken.

Did somebody here experience similar problems, like "wobbling"?

-intrcptr
 
Dang your having a heck of a time getting a bird that works for you! Have you flown in this area before? Could it be possible interference in that spot? Would def send it in for repair with your flight logs and hopefully DJI will take care of you under warranty if they deem it was the bird's fault.
 
You should only calibrate the IMU on a completely level surface. Failure to do so can cause all kinds of issues.

When flying with obstacle avoidance off does the motors make the sound you're describing?

Sounds like to me this is all user error. Without being their to watch you fly I have no idea what you're doing wrong, but clearly it's something if three P4P's are having issues.
 
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After calibrating IMU and compass, all problems were gone... for a while.

The first drone was returned primarily because of the very de-centered camera lens, the "wobble" was not very strong.

Second drone was returned because of the "gimbal creeping" and a "clogged" camera shutter release button; I sometimes had to press it a dozen times before ONE picture was taken. And the packaging was wrong, only three "silver" but five "black" propellers... final inspection anyone ?!?

Third drone flew perfect a few times, then the "wobble of death" came.

I also had a "standard" Phantom 4 (sold a few days ago), it always flew perfectly at the same places.
 
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I realise this is an old thread, but I just wanted to share my experience with an erratically twitching P4, which sometimes took over a minute to warm up, and which periodically struggled to hover notwithstanding countless "by the book" IMU and compass calibrations. This issue has been haunting me for the past six months.........
I live in hot part of the world in Australia, and after reading on other threads about pre cooling the bird before calibrating the IMU to iron out "twitches", I figured I'd give it a shot! I have read about some people refrigerating their drone prior to calibration but that sounds a little risky to me, as condensation could potentially cause internal problems either immediately or some time down the track.
So I simply placed the aircraft in front of the air-conditioner for half an hour, so the cool air entered via the battery port (battery removed). After an IMU calibration, hey presto! The belligerent P4 was back to its poised and elegantly stable old self!
So if you live in a hot climate and suffer similar symptoms, give it a go, it worked for me!
 
I had/have a similar issue. With some differences.

Flying a Phantom 4 Pro. Perfect balance no wobble using 3 different sets of props.

However. I add a mount between the landing gear (not blocking any sensors) from which I connect a 360 cam mount. Swapped the camera with a cell phone to make a live video call from.

Tested 3 mounts. All 3 without the added weight of a cell phone allow for the drone to fly perfectly balanced no wobble. As soon as i try with a cell phone the drone wobbles like one of the props is busted, or prop mount is loose or unbalanced.

I do the exact same tests with all the same props on my older dji 4 standard and it has no issue/wobble at all.

Only the pro does.

Verified:
1. Not the props
2. Not the camera mounts
3. Not the weight (least on the dji4 STD.)

Is it possible the very slight added weight of the cell phone is showing an issue with one of the motors that otherwise wouldn't show? Proverbial straw that broke the camel's back? Maybe there is an indiscernible wobble when there is no payload but it shows itself when the added payload of a cell phone is included?

Anyone ever experience this? I'll get a video of the effect some time in this coming week.
 
It is very important to get a good clean reliable compass calibration.
I believe both the compasses? or compass sensors on the pro are in the horizontal section of the landing gears, though it might be worth confirming that. Placing a phone or camera near them might be interfering with the local magnetic field (metallic cases, induced field from current carrying components. Radio transmissions?)
I think the reason the compasses are located there is to keep them as far away from other electrical components and radios.

Does rotating the phone 180 degrees have any effect?

These drones tent to crash with dodgy compass data...Its probably trying to correct for an incorrect/ impossible/ rapidly changing compass situation.

Having said that,I had a very slight but noticable rapid vertical oscillation and the motors were not smooth in the hover after a firmware upgrade.
I re calibrated IMU (flat surface) and compass (outside house and holding far above ground away from pipes, cables, cars and because concrete floors have steel rebar in them)
Was fine after that.
 
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