Yaw Drift

M

mbowser

Member
I'm close to the point where I am happy with my quad's tuning except for a slight amount of yaw drift. It probably wouldn't be a problem if I wasn't such a noob pilot, but I get all confused when it happens and I have trouble making my brain correct properly. I've trimmed my tx in both directions and it only results in pushing the yaw drift the other way. I can't seem to dial it in; it's almost as if the perfect step is 1/2 a trim setting. I've got a KK2.1 with 1.6 firmware and I have tried a bunch of combinations of PI Editor settings for yaw, but the closest I come to getting it to hover without yaw drift (or oscillations) is P=50, I=50.

Another possible cause is that I have a Turnigy 6X FHSS transmitter (cheap) and every time I do a receiver test, the values seem to change (meaning that they are 3 - 5 degrees off in either direction and have to be trimmed before flying). If I trim the rudder to 0 (in receiver test mode), push it all the way left or right and let it return to center position, the value on the kk will often be plus or minus 1 or 2 degrees. Is this common among cheap tx or is it common among all tx?

Any help is greatly appreciated.
-matt
 

jbrumberg

jbrumberg

Member
Matt- I have a relatively cheap FHSS Tx and cheap Rx (FS R9B). My Rx appears to fluctuate maybe one a one click adjustment +/- with a Tx battery change or after the Tx battery runs down. I am watching this, and I was going to post about this too; but you beat me to it. There is a little snow on the ground here, but I am going to do some more tuning today. I am troubled by the difference (lack of symmetry) with my roll/pitch P-gain:80 and I-gain:60. I would think that in a perfect set up it should be 60 and 60. There are a gazillion videos explaining this stuff indifferent ways. So far the different explanations and how to correct have not perfectly "clicked" for me yet. Drift can be due to wind, imbalance of PI settings, COG, rotor blades, motor outputs, motor/rotor-chassis alignments (although there is opposing opinions), and probably a whole lot of other stuff of which I am ignorant. My ignorance is probably a good thing. There are enough things for me to adjust one by one as I continue to try to tune my quad.

Good luck and keep us posted.

Jay
 

jbrumberg

jbrumberg

Member
Matt- I've been thinking abouut this, are you still doing your tuning indoors? And what are your limit settings? Jay
 

M

mbowser

Member
Jay, I got your PM, I agree it's frustrating to see all those youtube tuning videos and they seem to be absolutely all over the place as far as settings go. Being very new to this game, these settings are very foreign to me and I'm not sure I fully understand the P and I gain and limit concept. I think I would do much better with a better understanding of how each setting affects the stability of the quad. The only concrete description I have seen so far says that as your P gain goes up the quad will begin high frequency oscillations and when the I gain goes up the low frequency oscillations will begin. When you reach that point, dial it back. I'm still confused about what the Limit settings do.

Anyway, with that said, I used about 3 batteries worth of juice tuning this afternoon and I have managed to get the yaw drift mostly under control. I am still playing inside on the bed so I suspect the ground effects are not helping matters but I was able to sustain some decent hover time over the bed.
I'm keeping a spreadsheet of my PI Editor tuning values and the latest and most stable settings to date have been as follows:

PI Editor
Roll/Pitch P Gain: 40
Roll/Pitch P Limit: 40
Roll/Pitch I Gain: 25
Roll/Pitch I Limit: 20

Yaw P Gain: 60
Yaw P Limit: 60
Yaw I Gain: 0
Yaw I Limit: 20

Self Level Settings
P Gain: 60
P Limit: 60
ACC Trim Roll: 0
ACC Trim Pitch: 0

I haven't found it anywhere, but maybe someone can explain to me how the Self Level Settings are linked to the PI Editor settings. I am only flying in Self Level mode for now.

-matt
 

jbrumberg

jbrumberg

Member
Matt= turn off self-leveling. It's not helping you with PI settings. I believe a lot of those training videos recommend that you turn it off, but they mumble it real fast. It's taking away control of your right stick or try self-level with P-G= 0 and Limit = 0 you will have better stick control and still have some self leveling. I tried 0 and 0. I like it, but I have to say self leveling is challenging me for a different reason I never had it and I am having trouble getting used to it. When I put all my Roll/Pitch P-gain's and I-gains and limits and Y P-gains and I-gains and limits at similar settings things balanced out for my set up. One of those video guys said P"s and I's should be equal and I guess in a perfect situation that would be true, but statistically that should work out mathematically in any scenario I think. I was a psychologist not a statistician/mathematician. I hated those courses. Ground effects are not helping you either. One video or maybe a couple talk about how self leveling takes control away from the right stick and recommend some limit settings. I like them lower, but that could change. I am still learning this stuff myself.

Just a suggestion and think about it. If you like your Yaw settings, keep them constant and change one thing at a time. The first thing to change is do the 0-0 self-leveling. If that kind of works turn S-L off. If that kind of works match your roll/pitch P's and I' and limits. If that works do the same with the yaw settings and match limits. If that works Match your roll/pitch P's and I's to your Yaw P's and I's and limits. There's symmetry here. Theses are symmetrical flying machines. There should be some balance going on somewhere. If you find that you have to overcorrect your sticks in a certain way then limits should be looked at first I think. I approached this in this kind of manner with this kind of perspective. I am a newbee too, and I am still having my challenges as well. I wish I knew the answers. I hope I can help with an approach.

I hope this helps. We are in this together. Good luck-

Jay
 
Last edited by a moderator:


jbrumberg

jbrumberg

Member
Matt- Nice clip. I would not do that in my bedroom and my wife is a 6 hour drive away presently. Actually I probably could not do due to my mind set. I keep going back to all those tuning videos. To me I keep picking up what I missed the previous viewing. There's always something more to learn and to try. S-L does mess with the right stick. You tend to like it; I tend not to; a challenge for both of us. We will both find the "mix" with which we are comfortable. Good luck Jay
 

You must log in or register to reply here.
Top