Yaw params question

[Patnet]

I'm having a problem yawing left. It won't go. I'm going through the params and am unclear as to what the different abbreviations mean. For example, what's the difference between Yaw Control Rate OM and Yaw Control Rate IM?

Is there any documentation on this? Thanks,

This is what I've got. OM is way different to the other Yaw rates. Why would that be?

CTRL_YAW_ANG_D 0
CTRL_YAW_ANG_DM 0
CTRL_YAW_ANG_F 0
CTRL_YAW_ANG_I 1.99999994948e-05
CTRL_YAW_ANG_IM 0.0399999991059
CTRL_YAW_ANG_OM 1.25
CTRL_YAW_ANG_P 0.0500000007451
CTRL_YAW_ANG_PM 1.25
CTRL_YAW_RTE_D 240
CTRL_YAW_RTE_DM 386
CTRL_YAW_RTE_F 0.25
CTRL_YAW_RTE_I 0.725000023842
CTRL_YAW_RTE_IM 386
CTRL_YAW_RTE_OM 870
CTRL_YAW_RTE_P 1445
CTRL_YAW_RTE_PM 386

[chschmid]

[Patnet]

Thanks Christof, the motors aren't tilted.

Would you happen to know anything about the Yaw Rate in in Radio & Controls in Ground Control and Max. Yaw Rate in Navigation and Control Limits in Misc. Settings?

Also, do the PID settings even affect the ability to yaw, or are they just for stability when flying--ie stopping the quad from not flying straight?

Thanks for your help.

[LPR]

[chschmid]

I guess Larry just answered the use of yaw PIDs and limits.

Regarding your YAW problem, please post a pict of your craft and a log (e.g. PH, yaw left, yaw right). If you have a vid of that, post it. In the log we can see what is going on. Please provide a link to your log for download only.

Possible reasons:
wrong radio setup, no yaw left radio command possible
unbalanced torque CW/CCW which can have many reasons (one is a slightly tilted motor).

Cheers
Christof

[Patnet]

Larry, Christof, thanks.

Here are images of the craft. How do I create a log? I don't have the SD card reader installed. Is there another way to do it?

[Patnet]

Christof, are these what you mean? They are taken on the bench with the Telemetry log function in the desktop software. It saves as txt, so I don't see how you see them in the Desktop log viewer though, because they don't save with the .log extension.

I just ran through all the stick commands starting with left stick then right.

Yaw radio values show left and right OK in the Desktop Radio & Controls tab, by the way.


https://www.dropbox.com/s/bwmgsyr0a3p4k ... d.txt?dl=0

https://www.dropbox.com/s/wlymnuj6mikl4 ... g.txt?dl=0

[chschmid]

Hi Patnet

No, I would need the logs on the SD card - in flight.
It would be so much easier to find out what's wrong.
At least you found out so far that the radio is fine. Any chance to add an extension board with SD?
Otherwise you can measure the angle of ea motor with a waterlevel. Check the props for differences. Can you measure thrust? Sometimes props differ a lot. But in your case the torque difference seems to be heavy and you should be able to find it.

Cheers
Christof

[Patnet]

Hi Christof, thanks. I just checked the level of the arms. One arm is very slightly off level. Any suggestions of a packing material to use that won't compress over time with landings? I'll put it under an arm or motor screw.

I've swapped out the left two motors for the right two ones and seen a very slight improvement during a test flight just now. I yaw left very slowly when close to the ground, but not above about 6m. So maybe getting the advantage of a ground wash.

Right yaw is never a problem.

[chschmid]

Hi Patnet

Maybe use a washer. There are some precise washers from 0.1mm up. If you found the "guilty", you can even tilt it a little bit. Or even tilt two motors a little bit to have the same yaw torque CW and CCW. This is the easiest way if you can not measure props. Just trial and error until yaw feels the same for left and right.
PID's are only used for proper heading and lock in without over or undershoot. So nothing to tune yet.

Cheers
Christof