Interesting idea for setting gains/PIDs - RC Groups
Thread Tools
Jun 13, 2012, 12:32 AM
Atomic Playboy

Interesting idea for setting gains/PIDs

I was doing this with my KK board tricopter tonight, but had to stop because my servo went bad. Until the servo failed, it really seemed like a good way to adjust the gains... if not a little dangerous.

The KK board is running 1.6 acro. So as I understand:
Yaw pot = P and I for yaw
Roll pot = P for roll and pitch
Pitch pot = I for roll and pitch

So my plan is/was to hold it level over my head at half throttle. Then:
- Adjust trims so it doesn't feel like it's tilting in any direction
- Adjust yaw pot, twist it quickly and see if it oscillates side to side. If not, increase gain. If so, decrease.
- Adjust roll pot. Roll or pitch it by hand or with stick, feel for oscillation. Increase gain if none, decrease if some.
- Lightly move tricopter laterally in any direction and feel it try to move back to the original position. Adjust Pitch pot (I).

I am assuming I'm testing each one of these correctly. Remember the 1.6 firmware doesn't do what the pots say. They are P, I, and P+I for yaw. If anyone has a better way to test, I'm all ears. I keep crashing when I fly it, and I cannot keep it hovering long enough to figure out where the pots need to be. I'm just trying to at least get it as good as possible before I take it up again.

Thoughts? Suggestions on better ways to twist/turn/tilt it for testing each pot?
Sign up now
to remove ads between posts
Jun 13, 2012, 02:42 PM
KK Tri Flyer
mattcro's Avatar
If the trims and/or gains are way off then that's not a bad way to test... just be careful of those props!!

Set up a throttle curve (or endpoint) that prevents you applying full throttle, so that you can't accidentally knock the stick and rip it out of your hand.

Hold it out sideways and out to the side instead of over your head, so it can't fall on you if you lose your grip. It does not have to be held horizontal if your board is an ordinary KK and does not have accelerometers.

Once you've got it roughly set up and trimmed, do some test flights to fine tune the gyros and trim. Holding it in your hand will affect the gyro operation because you'll probably dampen the movements a bit.
Jun 13, 2012, 03:04 PM
Ya, matts on it. Was going to mention you'll notice some difference in actual flight and wind as well. I also found thermal drift is huge on mine. If its sunny out, after 1 minute flight itll vear off sharply. Disconecting lipo and waiting a couple minutes solves it.
Jun 13, 2012, 05:29 PM
Quad Whisperer
You only need to lower the throttle to zero for a few seconds to get rid of thermal drifting.
Jun 13, 2012, 06:38 PM
Atomic Playboy
I grabbed a new servo that truly has all metal gears in it (Spektrum A4020). Tonight I was able to hold the thing above my head and start doing some adjustments. It's WAY better than it was when I started. It really wanted to drift all over the place and oscillate before.

I've got Yaw at about 10%, Roll at 5%, and Pitch at 25%. Reducing the roll pot really reduced the drift, and reducing the roll pot significantly reduced pitch and roll oscillations.

One thing I noticed though, when I put the rudder stick to the right, the rear motor doesn't tilt at all, but works fine in the other direction. I thought it might be the servo, but I put the servo directly into the transmitter, and it's got full travel in both directions. I haven't flown it outside yet, waiting for my battery to charge. Maybe it's a non-issue, but it sure seems like something is up.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Interesting house idea dll932 Life, The Universe, and Politics 11 Jun 05, 2012 12:28 PM
Discussion Interesting idea dll932 Life, The Universe, and Politics 7 May 26, 2012 10:27 AM
Discussion What to look for when setting main gain? rkenosha Aerial Photography 3 Mar 03, 2012 08:52 AM
Discussion Ideas for a 25Kw set up wanted - Full scale OzparkPilot Giant Electric Planes 5 Oct 27, 2011 08:01 PM
Careful! SOLVED: Setting EPA for AL on 3 way switch - 0 gain switch of death tahoelight Aerial Photography 5 Oct 25, 2011 10:41 PM