Rolling when yaw

TheCif · Mar 16, 2015

Hi there!

After (and of course before) i did an advance imu calibration and sender calibration also, when i make a turn (yaw) the bird starts to roll. What can be cause this?

Thank you!

msinger · Mar 16, 2015

What is a sender calibration?

TheCif · Mar 16, 2015

MAybe i used wrong words.

when setting up the travel of the sticks of the transmitter.

happydays · Mar 16, 2015

Transmitter calibration you mean.

Rolling with yaw is not normal. Was the aircraft perfectly level when you did the advanced calibration?

Also, I would calibrated the transmitter first, then the phantom, not forgetting to calibrate the sticks in the remote assistant so they match with what the transmitter is saying - if that makes sense!

jumanoc · Mar 16, 2015

TheCif said:
Hi there!

After (and of course before) i did an advance imu calibration and sender calibration also, when i make a turn (yaw) the bird starts to roll. What can be cause this?

Thank you!

Use a lever App with you cellphone over the surface you calibrate your bird. If it is not perfectly leveled, phantom will drift when yaw.

iPhone:
https://itunes.apple.com/us/app/ihandy-level-free/id299852753?mt=8

Android:
https://play.google.com/store/apps/details?id=net.androgames.level&hl=us

6max3MAseZPLewvC5xCEi4KP7PB_XqejfirgGFOKWklh8Hl0HkVYZ2aSUKGP7ztJJf8=h310-rw

NTYgvvR8L7ZOjpW0vzIZbkg93zIfCsItBsyzWCyJqlg-T0oUSCsZT0lvRdec-t_--Q=h310-rw

N017RW · Mar 16, 2015

Are you saying one side or corner of the quad drops or dips when Yawing?

Does it then begin to fly towards the dropped corner/side?

TheCif · Mar 16, 2015

I calibrated on the floor of my house, which is horizontal, but i will do it again with a leveler.
So when i turning left the bird starts to turn and banking left also.

N017RW · Mar 16, 2015

Yawing is created by a difference in torque between the complementary pairs of motors. Their RPMs are adjusted accordingly to create the rotation as well as maintaining the attitude.

If you are dipping then it would seem there is an issue with at least one motor and/or its ESC.

Just a guess.

edonovanl · Mar 16, 2015

I have experienced the same thing but do not think it is unusual. If I do a rapid yaw, the drone drifts in different directions as the rotation proceeds. I think the sensor feedback system just cannot keep up with the speed at which the yaw occurs and it's the physics that makes the drone drift. The direction and speed of the wind are additional inputs and can make the drone drift more. A gain adjustment might help and I may try that today.

When I do a slow yaw, the drone is pretty good at responding and keeping position, since the system has more time to respond...

Also, prop balance could be an issue.

BlackTracer · Mar 16, 2015

jumanoc said:

Am I the only one who is wondering how you stand your Phantom on that picture frame??? :lol: :lol:

Sorry couldn't resist.

N017RW · Mar 16, 2015

edonovanl said:
I have experienced the same thing but do not think it is unusual. If I do a rapid yaw, the drone drifts in different directions as the rotation proceeds. I think the sensor feedback system just cannot keep up with the speed at which the yaw occurs and it's the physics that makes the drone drift. The direction and speed of the wind are additional inputs and can make the drone drift more. A gain adjustment might help and I may try that today.

When I do a slow yaw, the drone is pretty good at responding and keeping position, since the system has more time to respond...

Also, prop balance could be an issue.

Yea it is difficult to be sure what the OP is seeing and then describing. Wandering a bit is not unusual but 'rolling' is something different. I took latter as his issue. Maybe it is just wandering.

barefootbeachcombing · Mar 16, 2015

Sounds like yaw drift, perhaps.

Mal_PV2_Ireland · Mar 16, 2015

BlackTracer said:
jumanoc said:

Click to expand...

Am I the only one who is wondering how you stand your Phantom on that picture frame??? :lol: :lol:

Sorry couldn't resist.

Haha no, you're not alone mate

I might have used a real level though.

TheCif · Mar 17, 2015

edonovanl said:
Also, prop balance could be an issue.

As you mention it, it did with a new set of chinese prop and also quaked the whole bird.

edonovanl · Mar 17, 2015

Now I am wondering about my previous post about fast versus slow yaw - tried it yesterday and it was the opposite of what I thought, but it was pretty windy so maybe that's what it was. I'm going to wait for a calm day and try it again because after reading your posts, I don't think my drone maintains position like it should. Not too big a deal because I mostly fly in ATTI mode so when I lose GPS, I'm prepared to handle it...

N017RW · Mar 17, 2015

DJI does not spec 'yaw induced drift' or similar.

It is very difficult for the control system to dampen this as it will need to dynamically tilt the a/c as it spins to cancel any detectable drift.

lake_flyer · Mar 17, 2015

agreed, I think also, the more rotors the less yaw drift. On top of that we have a low end flight controller in our Phantoms.
Not at all bad, but it is still in the toy quadrant on my chart. I'm sure the high end controllers have more code and much more sophisticated algorithms to work with.

A bit drift in yaw is perfectly normal and should be accounted for when flying near people, other living beings and objects.