Drifting even after calibration

[Shadow Art]

Phantom 2 with H3-3D gimbal had a few rough "landings" due to ring state vortex. Replaced gimbal, checked software update, did advanced IMU calibration* and controller calibration. Compass calibration is good also. (* I did get a warning that MC was too warm during IMU calibration but ignored it because it was at room temperature) Shell does not appear to be warped or damaged.

What else would cause it to drift severely?

 

[Damon]

Possibly GPS cable is not firmly seated or GPS sustained crack/damage from the impact?

 

[skidtrash]

I had the same problem... sent my unit to DJI ...it been there for 6 weeks havent heard a word from them

 

[Wedeliver]

I

Phantom 2 with H3-3D gimbal had a few rough "landings" due to ring state vortex. Replaced gimbal, checked software update, did advanced IMU calibration* and controller calibration. Compass calibration is good also. (* I did get a warning that MC was too warm during IMU calibration but ignored it because it was at room temperature) Shell does not appear to be warped or damaged.

What else would cause it to drift severely?

I have been working on this issue and I have a couple questions. when your craft is "drifting" is it level? If you observe it, is it tilting just a little? Does it go around ina big, like 150or20 foot diameter circle? can you hear anything at all from the motors that is just a little off, like a clicking or popping, not loud but continous.

thank you

 

[EMCSQUAR]

If you have a drifting issue, it's best you do the full calibration route. I've had a few brought to me after crashes and I start from ground zero - first check for loose connections - I hot glue ALL solder joints, check to make sure arms are not bent, motors are level and tight, props are level then do a default settings reset (tools page), then do a stick calibration, an advanced IMU cal then compass cal. Doing these helps immensely in getting Phantom back in "smooth mode".

 

[houldsworth1]

I seem to have the same issue. I had two crashes today - both into trees - but the first time it stopped in the tree and the second time it only dropped about 2'.

The Phantom now drifts but how far and how much seems to vary. Sometimes it is just a little, other times it seems to be continuous but slow. If I switch to ATTI mode I can see the unit straighten up and seem to fly more level. One of the props is definitely a little out of whack.

I have tried two advanced IMU calibrations and a compass calibration but still have the same drifting going on. Oh, and I get the 'too warm' message during the IMU advanced calibration also, even after leaving it along for hours in a 65f house.

 

[Wedeliver]

I seem to have the same issue. I had two crashes today - both into trees - but the first time it stopped in the tree and the second time it only dropped about 2'.

The Phantom now drifts but how far and how much seems to vary. Sometimes it is just a little, other times it seems to be continuous but slow. If I switch to ATTI mode I can see the unit straighten up and seem to fly more level. One of the props is definitely a little out of whack.

I have tried two advanced IMU calibrations and a compass calibration but still have the same drifting going on. Oh, and I get the 'too warm' message during the IMU advanced calibration also, even after leaving it along for hours in a 65f house.

That mc is too hot we all get and we are supposed to just hit ok and the process should be allowed to complete. Sometimes you need to do it twice. Have you looked at the compass on the leg to see if it was damaged, cable coming loose, or twisted or moved on the leg? Also, you are seeing the craft is not level in GPS then I would look real close at your props and motors.

Good luck and keep us posted, especially if you find what the problem is.

Craig

 

[shadowband]

Oh, and I get the 'too warm' message during the IMU advanced calibration also, even after leaving it along for hours in a 65f house.

Not to worry - That message is always output during IMU advanced callibration. It's a known issue that should just be ignored, and the advanced callibration should complete within 10 minutes. It's even noted during the following Phantom 2 Vision+ Assistant tutorial:
http://www.youtube.com/watch?v=695FLzWT_ko

 

[Shadow Art]

Someone in another forum posted that the IMU and compass calibrations should be done while the craft is facing magnetic north. I haven't read this tip anywhere else.

 

[houldsworth1]

That mc is too hot we all get and we are supposed to just hit ok and the process should be allowed to complete. Sometimes you need to do it twice. Have you looked at the compass on the leg to see if it was damaged, cable coming loose, or twisted or moved on the leg? Also, you are seeing the craft is not level in GPS then I would look real close at your props and motors.

Good luck and keep us posted, especially if you find what the problem is.

Craig

Thanks. Good info.

I took it for another flight and it actually seems a little better even though the GPS lock took a long while to achieve. It seemed to get better with some altitude so perhaps the house / trees were interfering with the signal since I was flying it in my back yard.

One of the props is slightly bent downwards. I know it's the prop because if I spin it I can measure the gap over the 'arm' and, if I switch it with the other prop, then the gap issue follows the bent prop.

Someone bought me a set of prop guards but I hear mixed reviews on those so I haven't fitted them yet. Should I ?

 

[Shadow Art]

Based on the replies I figured my problem was structural and not software. Once I started taking things apart and looking closer, I noticed that there was wear marks on the outside of two motors and scuff marks on the inside shell where the motors sit. There didn't appear to be any contact between the motor and the shell but there must have been enough (maybe under load) to just slow those two down enough to cause them to run off speed. Hence the drift.

 

[N017RW]

Someone in another forum posted that the IMU and compass calibrations should be done while the craft is facing magnetic north. I haven't read this tip anywhere else.

That is NOT true.
Current or 'starting' direction the a/c is facing plays no part in IMU calibration or compass compensation.

 

[Wedeliver]

Based on the replies I figured my problem was structural and not software. Once I started taking things apart and looking closer, I noticed that there was wear marks on the outside of two motors and scuff marks on the inside shell where the motors sit. There didn't appear to be any contact between the motor and the shell but there must have been enough (maybe under load) to just slow those two down enough to cause them to run off speed. Hence the drift.

Actually nobody knows why your quad is drifting but the replies speak to the reasons that it can happen. We have heard stories of the GPS module, which is located in the top of the shell, being found to have a crack which caused problems. That might have been mentioned on the first page of this thread. I have seen where the compass on the leg can be damaged yet without close inspection it is not noticeable. with a quad that does not fly level in GPS mode, we can make an assumptions that the motors are having a hard time keeping things level and what might cause that becomes the question. Could be motor issues, bent props, bad software settings, maybe a bent arm.. Process of elimination and you will probably find the cuplprit and manage to have no drifting in the end. good luck and keep us posted.

If someone would like to comment, correct, add to. etc the above, this is an important topic for discussion as I am constantly dealing with it. I have one Phantom v1.1.1 that only drifts when I put big legs on.. I have messed with the compass till the sun went down.. works fine with the old legs... but I want it to work fine with the big legs...