Phantom is not stable after IMU calibration.

BlackTracer said:
Pmcdn said:
So, after all the back and forth trying to get the paper pieces just right under my Plus V3's skids to fix the yaw drift, which I probably did about 8 to 10 calibrations, I decided to be smart and do a cali on a level surface first!

My Plus is only a month old and last week or so I noticed it drifted about 3 feet or more to the rear and left when I yawed. So, I immediately started raising the skids on the opposite side and trying to counter the drift, assuming my IMU wasn't level inside the quad.

Today, I got my bubble level and discovered that my kitchen granite counter tops are dead on level, so I just did a calibration there, flew it and now it is dead on when it yaws. It's like it is mounted on the end of a pose when it yaws! It's fantastic!

If only I'd thought to do a calibration on a level surface FIRST ;-)

Congrats but why wouldnt you do it on a level surface in the first place? That is one of the criteria of an IMU calibration.

+1000

I always suggest doing it on a surface levelled to the horizon. I use a ball bearing and a tile that i know is dead flat. My phantom does high speed yaws on a dime.

You need to remember how important a calibration is and what it does. The phantom is taking a new snapshot of what it thinks is the yard stick is. I know the phantom is a bigboytoy, but on the othe end of the spectrum, I calibrate machines at work and if im off +/-10cm, it means half a million in reworks.

If you want happy flying, like your head, keep the phantom cool and levelled.
 
BlackTracer said:
Pmcdn said:
So, after all the back and forth trying to get the paper pieces just right under my Plus V3's skids to fix the yaw drift, which I probably did about 8 to 10 calibrations, I decided to be smart and do a cali on a level surface first!

My Plus is only a month old and last week or so I noticed it drifted about 3 feet or more to the rear and left when I yawed. So, I immediately started raising the skids on the opposite side and trying to counter the drift, assuming my IMU wasn't level inside the quad.

Today, I got my bubble level and discovered that my kitchen granite counter tops are dead on level, so I just did a calibration there, flew it and now it is dead on when it yaws. It's like it is mounted on the end of a pose when it yaws! It's fantastic!

If only I'd thought to do a calibration on a level surface FIRST ;-)

Congrats but why wouldnt you do it on a level surface in the first place? That is one of the criteria of an IMU calibration.

Wasn't thinking I guess, which I pointed out above. When I noticed it not yawning properly was right when this thread began to thrive. I just assumed that mine needed to be counter balanced in calibration. I was wrong.
 
I had the same result. I leveled the platform I built so it was spot on level. Then when I did the calibration with the Phantom on the platform I knew the Phantom was level. Did the calibration and took it out for a quick test and the yaw was very close to perfect. It was so cold out that I couldn't take it for an extensive flight. So starting off on a perfectly level surface is the starting point. Those that find the yaw is off after that could follow the procedure outlined in this post.
 
Lol quite amusing... I've had this issue for ever and just thought 'eeeeh bit wierd... bit oh well'
I'm sure it was perfect out of the box, but I just don't remember watching it....

but yeah the last flight I was thinking she does drift a fair bit when going round in a circle...

My table is completely level as tested with level... but I'm guessing the variation comes from the 2x black foam rubbery things that sits in each skid ???
Will put a level over the Phantom tomorrow and then do the paper sheet method..
3:30am... can't sleep... kind of forgot what I read as I read like 3 diff threads about this lol.. I just need to focus on 1 side right ?? Like I mean I don't need to concentrate on each corner... just either the left or the right, right ?

I'd take the black things out.... but took me like an hour to take 4x out and replace then last time... little buggers are pretty sticky!!

Anyone ever done an IMU with it upside down :p seems like it would be pretty level...... course the Phantom might start flips....
 
I have been having issues with my 2plus holding/getting a good calibration. Using 3 ideas from different threads I just tested mine and it spun without taking a side trip wherever it wanted.
Here is what worked for me tonite.

1.I had balanced the table used to calibrate the IMU, all level all around. then I saw another idea here. Run the level across top of motor mounts. I did this and they were NOT level even though the "aircraft" was. I shimmed slightly to get a level running both corners(motor mount post).

2. Did calibration only on cold mc

3.Took a small magnet and degaussed the compass( pass it around nearby while watching the reading on pc) my one # was 20700, a few swipes and it was 12600 and all the rest were well within range. First time I did this .

test flight tonite --straight up, great spin, great control.

a big Thanks to all the guys figuring things out on this stuff


Most likely will still install the new antistatic compass tomorrow when it gets here.
 

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