IMU Calibration

[Explorocam]

Hi all,


I'm calibrating my IMUs and I'm using a bubble level on the top of my F550 to make sure it's level when calibrating. But even after calibration I'm still getting a slight drift to the right. So I added even a little more wedge under the right side of the hex to lift the right side. I still get a little drift to the right though. I've even lifted the right enough that it is noticeable to the naked eye and yet I still get a little drift. Any idea why this is occurring?

 

[kloner]

your recalibrating when you lift the side it's flying towards? keep putting it the same spot on the table each time, you can get it perfect

keep an eye on the numbers it shows and move it the right way, you can fake it to each degree it measures. pieces of paper under a leg was a really accurate way to slightly or masively move the controller with accuracy

 

[DesJardins]

I have a tiny drift to the right so I'll need to do this also

 

[Explorocam]

I'll keep trying something but I'm doing exactly what you said, lifting the side it is drifting towards, hitting calibration and then write. But the results are always the same. Both Assistent and Naza have been updated {1.8 and 2.02}.

Now when I plug it in and go to the calibration I see that the Acceleration is X=0, Y=0, Z=1.
The Gyroscope degrees is kind of jumping around X=0~+/-.04, Y=0~+/-.04, Z=0~+/-.04
The calibration numbers notice movement I'm putting and I am using a bubble level, so I'm a bit confused. I'll try putting the bubble level directly on the Naza box case itself and see if that makes a difference.

Not sure what all this means but its as if the calibration is not actually taking affect.

your recalibrating when you lift the side it's flying towards? keep putting it the same spot on the table each time, you can get it perfect

keep an eye on the numbers it shows and move it the right way, you can fake it to each degree it measures. pieces of paper under a leg was a really accurate way to slightly or masively move the controller with accuracy

 

[kloner]

im not sure, but i didn't mess with a bubble level, i messed with the problem i saw in the sky and made the side it went higher. beyond that, not sure what other way to make it stop a drift. mines probably not bubble level hovering, but it hovers in place without a breeze

 

[Explorocam]

im not sure, but i didn't mess with a bubble level, i messed with the problem i saw in the sky and made the side it went higher. beyond that, not sure what other way to make it stop a drift. mines probably not bubble level hovering, but it hovers in place without a breeze

Well, It's pretty breezy now but I tested it out and it might be a little better, but I'm not sure why it is if it is.
BTW, Just out of curiosity; WHat are your basic and attitude gains set at?

 

[kloner]

basic is 120-190 on ele/ail with a dial,,, 130 vert/rud and 80 atti

you understand that part about not messing with a bubble level and to mess with the problem? reading your reply makes it sound like it's suppose to fly level if the things bubble level...level. that's not the case, that's how you got it...... mine was lik -.7, .4, .8...... i hit calibrate, flew it, was worse. Brought it back in and made the side that it went towards higher with sheets of paper, think the numbers went to like -.4, .5,.7 and hit calibrate and it hovers hands free in manual if i don't touch anything... it's crazy flat even flying

 

[Explorocam]

Ok, I'm start to really get bothered by this IMU calibration. I think that maybe mine is not working. As you all know I tried calibrating while raising the side of the craft that it was drifting towards. (it drifts to the right so I raised the right side and calibrated) This did not seem to do anything regardless of raising different hights. So I experimented by lifting the left side, same effect, didn't really notice much of a difference. So tonight there is no wind {dead calm} and I raised the right side again this time at least a full centimeter and it still drifts to the right, I'm about to try 2cm but I'm starting to get nervous about going to far. How far am I supposed to raise the one side to level this damn thing off?

I know it's not the compas because it holds perfect in GPS and the Return to Home works great to, no toilet bowl effect or anything. But when I'm in altitude mode there is drift to the right, enough drift that when I'm in forward flight I have to apply a little left cyclic to keep it going straight. Plus I have to give more cyclic to the left if I want to fly sideways to the left than I do to the right cyclic when I'm flying to the right.

I check my radio to, I checked the trims and the sub-trims and they are all at "0". I don't know if I should try reinstalling the the firmware or send it back to DJI but this is really freaking annoying me.

Am I doing it wrong?
Should I apply sub-trim?
should I rais the right side up like six inches or something?
Should I send it back to DJI?
These are all the freaken questions in my head right now.

Please help anyone.

 

[skipper1]

It doesn't cost anything to use some sub-trim and if it works, it's fixed.
My little quad with naza, indoors drifts to the right also and have been doing the same thing you and kloner are doing, tricking it by raising one side and like you, no difference.
If you figure out how to keep it from drifting, you need to post the solution for others, I'll do the same.

 

[ChrisViperM]

A few things I would do:

Create a complete new Model in your Remote - could be that you have some sort of mixer activated in your current model, which you don't get rid of by just calibrating.
Flash the firmware of your IMU....can be the same version you are using, just flash it to get rid of any existing settings....bind it with the new Model in your Remote and make all ground settings
Be very careful when setting the Center Of Gravity...this is sometimes a bit confusing with all the +/- settings...this has always created problems in the past.
If it's just a liitle bit drifting, you either do it kloners way, or give it a little sub-trim like skipper1 said

If that all doen't help, try to switch motors/ESC's...the left ones to the right and vica versus

If you are still having troubles, send the IMU to your dealer

Chris

 

[Explorocam]

A few things I would do:

Create a complete new Model in your Remote - could be that you have some sort of mixer activated in your current model, which you don't get rid of by just calibrating.
Flash the firmware of your IMU....can be the same version you are using, just flash it to get rid of any existing settings....bind it with the new Model in your Remote and make all ground settings
Be very careful when setting the Center Of Gravity...this is sometimes a bit confusing with all the +/- settings...this has always created problems in the past.
If it's just a liitle bit drifting, you either do it kloners way, or give it a little sub-trim like skipper1 said

If that all doen't help, try to switch motors/ESC's...the left ones to the right and vica versus

If you are still having troubles, send the IMU to your dealer

Chris

OK, I'll try creating a new model in the radio and reflash the IMU. because the lifting one side did not change anything. Hopefully that will help.
I contacted DJI and they said if this doesn't help to send it back to the dealer.

 

[Explorocam]

your recalibrating when you lift the side it's flying towards? keep putting it the same spot on the table each time, you can get it perfect

keep an eye on the numbers it shows and move it the right way, you can fake it to each degree it measures. pieces of paper under a leg was a really accurate way to slightly or masively move the controller with accuracy

Dude, my numbers jump around as if it's being moved while it's sitting perfectly stationary. I already raised the right side (drifts to the right) about 1cm to 1.5cm. This didn't help.
Are my numbers supposed be jumping around?
Doesn't 1 to 1.5cm seem a little high of lift to you?

 

[kloner]

make us a movie of the assistant when you hit write or go or whatever makes the new setting stick I only hit it twice in my life so i'm a little green. Did you say something about an error in imu cali before?

 

[Explorocam]

make us a movie of the assistant when you hit write or go or whatever makes the new setting stick I only hit it twice in my life so i'm a little green. Did you say something about an error in imu cali before?

This is what I see. The gyroscope degrees kind of jump around not sure if this is normal. The little candles are what I used to raise the right side and still no affect.

 

[kloner]

way too hi, maybee that's the problem..... when you hit the button are the numbers different than when going in and starting the imu calib

 

[kloner]

just watched the movie,,, when you raise that the numbers should change,,, alot that hi...

whos your dealer?

 

[Explorocam]

No, the numbers don't really change regardless of how far I raise the one side or the other. My dealer is http://www.rcflightstore.com/.

I didn't get much of a change when I raised the right or the left side. I tried lifting the right side that much to see if there was a difference, not much of a difference, it still drifted to the right.

 

[kloner]

those numbers are your gyro output or whatever..... the jumping around is normal, the not moving when it is isn't

Try this, take the model in front of the pc and hold it in your hand and see if at a certain point of level that numbers don't rise and fall alot more than what we saw.... if it never moves it would appear your gyro is messed up

 

[Explorocam]

those numbers are your gyro output or whatever..... the jumping around is normal, the not moving when it is isn't

Try this, take the model in front of the pc and hold it in your hand and see if at a certain point of level that numbers don't rise and fall alot more than what we saw.... if it never moves it would appear your gyro is messed up

I've done this before and they do kind move but do jump around. The numbers do go higher and lower in the scale of them jumping around. I'm about to setup the model again on my radio and I've installed the assistant again and when the has a new model I'll reflash the IMU firmware.

 

[kloner]

so if you can, lift the right side ( think that's where it drifted till you see a number change that corresponds to the direction being observed by the imu, then calibrate it.....