Autotune guidance

Since this has been the topic of discussion, I figured you might want to see it and know a little about it.This is the beast in all of the above postings. I made the 8K battery boxes, ADS-B Mount, the orange electronics plate, and other misc bits and bobs. My two favorite additions are the Electronics plate, eSun ProPLA Orange, and the Battery Boxes. The Electronics plate is printed at 100% infil and is 4mm thick. It is surprising light. I spaced the Plate 30mm off the Tarot top plate so that I could make all the motor and esc connections via xt30 connectors. The Holybro PM07 PDB Power module is mounted on the bottom of the plate. If any of you have or had a 680 Pro, you know how little space and how much of a pain it is to work on. 10 M3 screws on the top plate and all the electronics come off in one piece. Maintenance or repairs are now a snap.

Just so I know what to expect…

After Autotune completes, then I flip my Autotune switch from high to low then back to high… It’s not going to start autotuning again right? IT will only Autotune once per arm/disarming cycle? In other words, I won’t be fighting autotune as I land it?

After AT completes, (with tadada sound and GCS notification), you leave the switch as is, land and disarm.
If you refresh params, you will see the new values at the tuning Page.

Take off in stabilize and get ready to take over, to test the new tune.

Take a screenshot before the tune just to compare or revert to if something goes wrong

Ok, now I am confused again. Previously in this thread, it has been discussed, and I thought established that,

(this also correlates with the Autotune guidance in the documentation at: https://ardupilot.org/copter/docs/autotune.html) where it says:

  • When the tune completes the copter will change back to the original PID gains.
  • Put the ch7/ch8 switch into the LOW position then back to the HIGH position to test the tuned PID gains.
  • Put the ch7/ch8 switch into the LOW position to fly using the original PID gains.
  • If you are happy with the autotuned PID gains, leave the ch7/ch8 switch in the HIGH position, land and disarm to save the PIDs permanently.

It was the original reason for this thread actually, because the original poster was having trouble getting the new PID’s to get saved…

That said, all the videos I’ve seen on YouTube do as you describe, and seems to work fine. It’s also how Randy Mackay does it in the video in the documentation at https://ardupilot.org/copter/docs/autotune.html. At the end of his video, he describes landing with the switch in the high position to save or low position not to (like what you claim), So this is why the confusion. Unless I am misinterpreting, the video at https://ardupilot.org/copter/docs/autotune.html doesn’t match the written instructions on the same page. Am I wrong?

I just want to clear it up, once and for all because I was about to Autotune and flip the switch back and forth once before landing, but I don’t want it going back into Autotune mode while I’m landing.

The instructions are correct, they both end up the same way. In your switch in autotune, land-disarm-save tune.

Confusion may rise by the fact that autotune may be selected as rc option, or a flight mode. Also you may get confused by the option to on and off autotune switch, in order to test your new tune mid-flight…

I personally, NEVER tested this option, or seen it working, neither I would suggest it to anyone.
Spare a few seconds, land and test your tunes

A! Not forget, as long as you move the sticks AT isn’t engage, so don’t worry that you might re enable AT as you land

Best,
Dimitris

My whole point of the post was simply this. I watched randy’s, Dennis Baldwins, Lee’s Painless 360 and a few others. I don’t know how, but I was able to do an initial tune, it was a little breezy, so i decided that on a really calm day, i would run a few tuning sessions and see if the PID values would change at all. This is where I ran into issues. For the life of me, I couldn’t get the craft to save the new pids. The problem I had, was that no matter what i did, arm fly autotune, set low, set high, and land, the craft refused to disarm. Through all of this, I’ve learned a great deal. I had planned on flying this weekend, the weather has not been cooperating, rain the last few days. I’m hoping that Monday or Tuesday this week I’ll be able to run the procedures once and for all, taking notes as I go. @Leonardthall and @smartdave have given me a wealth of incite and understanding on the Autotuning process and key set up features. I also found this spreadsheet from @xfacta, super helpful since the charts in the tuning wiki dont have gridlines to chart pick. New Tuning Instructions Wiki Page. Thanks @xfacta Shawn for doing the hard math and setting up the spreadsheet. Where did the formulas come from? I have an aeronautics degree and some of them look familiar.

I didn’t do any real work - It’s all Leonards hard work, I reproduced his graphs in Excel to derive the formulas.

Ok, according to what you say, I will consider steps 7 & 8 as being optional steps then. I just tuned my Roll axis, skipped the Autotune documentation steps 7 & 8 and it did save the new values. Thanks.

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After a successful roll autotune and an aborted Autotune pitch only attempt, I just checked my parameters and see that my ATC_ACCEL_P_MAX changed from “108700” to “0”. I got the value 108700 from the spreadsheet priveded by @xfacta - Should I change this back before attempting Autotune on the pitch again? When compare parameter from before the roll autotune and after the roll autotune, I see it was thesuccesful roll autotune which changed it, but that seems odd because in the roll autotune, it got a precise value for the ATC_ACCEL_R_MAX, and I don’t think the ATC_ACCEL_P_MAX should’ve changed… Am I correct that ATC_ACCEL_P_MAX being the maximum pitch angle, is the reason Shawn’s spreadsheet gives a value to limit the amount of tilt angle allowed?

I also noticed as I was flying it out to autotune the pitch that it was pitching very hard, like looked like it was about to flip if I was hard on the sticks, so I think this is related.

Yes, change it back.

Send a log of that flight if you can.

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Just to be clear, I know the wiki is a bit out of date on this. The only thing required to save gains is to disarm in autotune mode. You can switch into whatever other modes you like but it is not a requirement. Switching out and back lets you try out the new gains but it is not required. If its all going well just land and disarm in autotune, other wise you can land in stabalize and switch to autotune with minimum throttle then disarm.

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This is the log from my successful roll autotuning:

And this is my aborted autotune of pitch:

The reason I aborted was I decided to yaw by 90 degrees so that the pitch wasn’t affected by the breeze as much, as in, turned it into a crosswind instead of a tailwind. Then the breeze picked up and blew it kind of far away and I nearly lost track of the drone’s heading, so it got a little scary watching the drone drift away and not being able to see which way it was headed. Oterwise, the pitch autotune was going as planned other with the exception of the fact that the when I’d go full pitch forward or back, it was really harsh looking.

The other parameter that changed was ATC_RATE_FF_ENAB. It changed from “1” to “0” after successful roll autotuning. I figure it’s supposed to have changed, but if I’m wrong, will you please let me know?

On a separate note, you might notice in my log file that after all that flying, I got it landed and my battery still showed as having 98% on QGroundControl. My battery monitor has been working fine otherwise, but when I went to arm it again, it still showed 98% full and at the same time failed a pre-arm check due to low battery failsafe. I figure it was a glitch or problem with QGroundControl, battery or telemetry but I’ll deal with that bit next attempt at autotuning my pitch since I don’t see any changes in my battery related parameters and the failsafe still seems to work (plus I am only flying short flights.)

Actually… I went to upload a short clip of the extreme tilt angle I saw, and when I did, I see in at least one place where the roll is also pitching so extreme:

And I think this is because I also reverted my PSC_ACCZ_I & MOT_THST_HOVER back to defaults… I think I will tone those down a bit from defaults, maybe to values given by the Tuning Process Instructions. and with accordance to your advice:

So… Maybe the pitch thing is not related afterall.

I am still not sure if I should revert ATC_RATE_FF_ENAB back to “1” (is at “0” now after successful roll autotune, which is when it changed) …?

I’m sorry if this wasted your time but thanks again for your help.

Out of curiosity. If you have retractable landing gear. Should you autotune gear up or gear down?

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I will have this question too when I get ready to tune my s1000, which will be when I am done setting up the X8. My plan is to start with the X8 as practice, then do the s1000 since it’s going to carry some expensive filming gear.

Ha. This is directly related to my X8. Lol

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Tarot TL65B44? or…? I didn’t even know I could add retractable landing gear for it… Oh the possibilities… Don’t get me started… :money_mouth_face:

Oh wait… mine is 3DR X8. Yours might be different x8…

Mine is the Tarot X8 V2

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You started the tune with ATC_RATE_FF_ENAB set to 0. Probably after doing the stability check.

This should be set to 1 after a successful autotune.

Yeh it is working correctly in the log.

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Upon double checking, I see you’re right. What I do is “save to file” in Mission Planner after I make any changes. That is how I compare changes and am able to revert back at any time or see what changed, etc. I should probably look into how to analyze the log files…

Ok, so I will set this back to “0” for now, since I’ve only tuned one axis successfully (Roll). After successful pitch autotuning, I’ll set it back to zero again before I autotune the yaw, since any successful autotune seems to change it.

That makes me feel better. THANKSx1,000,000