This is a discussion re the ArduCopter-3.1 AutoTune feature.  A place for people to report successes and failures, ask questions and get answers.

The AutoTune wiki page is here.

 

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Flew in 15 to 20 MPH winds yesterday and the auto tune derived PIDs were very stable. Flew in Stabilize, Loiter, and Circle.  The quad was much less jerky in Loiter than using the default PIDs.  And while I need some more flights to be sure it seemed I was getting longer time in the air before the battery alarm went off.  Probably because it was working less hard to stay put and stable.

It seems the 10 minutes it took to do auto tune from the defaults was because the defaults were far from the end result.  I suspect if I did it again to 'tweak' the first set it would go much faster.

So I'd declare this a success.  Auto tune works fine.  It's a great addition.  Here is what I've concluded:

- If you change from the default physical config autotune will take longer.  In my case it was 880 motors, 11 inch props, 5Ah battery plus 1Ah battery, flying at 6,300 feet elevation, elevating the APM about 2" above the base and the power distro module.

- To get the autotune switch to work you must have a wire connection between ch7 or 8 on your controller and the  7 or 8 input to the APM.  I had to add that wire.

- The less wind you have the faster it will get done. If the PIDs you start out with are far from ideal it's going to take up to 10 minutes or so. The more time you spend driving it back to the test area the less time is available to complete the tune process.  I got through it successfully only when I had a day that was completely still so I had to pull it back from drifting off only three or four times, and for very short distances.

- Be sure to read and understand how to preserve the PIDs that result. I had one false start because I complete the tune then flipped the wrong switch and those were lost.

- Assure the GPS has a good fix before you start.  I left power on for about 2 minutes sitting on the ground before arming to assure it had plenty of sats.

- Assure all the physical parts are secure and not moving around when the copter does the rather violent roll and pitch maneuvers that are part of the auto tune process.  If something moves around it will create noise in the accel data and the process may fail or result in bad PIDS.  I ended up bracing my camera mount laterally to stiffen it, just for the autotune.  Before I did that I could see it flexing a bit side to side even while moving hard left and right in Stabilize.

These notes are based on my experience. Your mileage may vary.

Hi Aaron,

How is you autotune going?

It worked really well! Took less than 10 minutes and my copter is way more stable now. I have 4s, 14inch props, 750 kv motors so pretty far from the defaults.

Is there info in the log that could tell me what PIDs were when autotune stopped. I had almost finished, but it took 12 minutes and the battery died. I'd rather not kill another battery, so I was hoping I could find the settings that it was last on to start from there. I'm thinking the RPgain, RDgain and SPgain are what I need, but SPgain is pretty high, around 9.5, so I don't want to render it unflyable if I'm wrong.

Thanks,

Barry

Attachments:

Hi Barrett,

Roll Rate D = 0.0145
Roll Rate P = 0.25
Roll Rate I = 0.25

Roll Stab P = 6.75

Pitch Rate D = 0.015
Pitch Rate P = 0.25
Pitch Rate I = 0.25

Pitch Stab P = 6.75

Those are what Autotune was looking like it was going to give you.

Could you tell me a bit more about your copter. Weight, Size, Motor kv and power, cell count, props and a couple of photoes if you have them.

The reason I ask is you have pretty much maxed out autotune. We may need to give more headroom for copters like yours and I would like to know what that is.

Thanks.

Thanks Leonard.

 Basic info: RCT 550 hex frame, RCT 2812-1000kv motors, RCT 10x4.5 CF props, 2-3000mah 3s e-flite in parallel, about 2020gm AUW. GoPro and gimbal are not on right now. I probably need a little bigger motors, but it's what I've got right now. I'll set the gains later and give them a try.

Leonard,

 I just read your last paragraph. Not sure why I missed it before. Do you mean it maxed out PIDs, or it maxed out the actual tuning process? If the latter is the case, it may be due to it being a bit gusty while I was trying to tune. It was definitely fighting the wind. It's been so windy here in Austin I got tired of waiting for calm. It definitely seemed to be flying much better towards the end of the process. I wouldn't think my copter is anything out of the norm.

Thanks,

Barry

Leonard,

 I tried the settings above. It was vibrating so intensely as I throttled up I wasn't willing to takeoff. I set PIDs back to default except for D, which I'm not sure what default was. I set it to .001. Is that ok? Would wind have caused the long autotune time and high PIDs? On my quad autotune was about 6-7 minutes from default, and 1-2 minutes if I felt it needed re-tuning. Hoping for a calm morning soon.

Barry

Hi Barrett,

Yeh, this is strange. Maybe it was the wind. Looking closely at your Autotune measurements they are strange in their shape. Sorry, all I can suggest is that you try again in calm conditions. I tend to find first thing in the morning the best time for calm conditions.

D should be 0.004 (but I would start with 0.006)

Good evening to all autotuners,

trying to tune mini spider hex from Blackout. Flies OK just as it is but when I invoke autotune it finishes itself too early. It just never starts fliping from front to back. I have done many attempts also with different starting PID values but so far no luck. Log file from the last flight is attached (five autotune attempts with landing and disarming/arming in between of the attempts).

Copter configuration:

Blackout Mini Spider

6x Cobra 2204/28 2300Kv

6x Afro Ligh 12A ESC w/BLHeli 11.2 (Demag compensation OFF, PWM Frequency HIGH, Motor Timing MEDIUM HIGH)

3S 2200mAh nanoTech 25-50C

OpenPilot REVO ArduRevo (latest code compiled by stefan, in terminal it says V3.2-05)

Props: GF 5030

Any ideas what should I try to get autotune to finish? It worked very well for me on two previous builds (TBS Discovery and mini quad 250).

Attachments:

Is it possible to show a comparison? I'm just wondering what it should look like.

Here are 2 logs from today with no wind. The P&S Stab are really high. Are the measurement shapes more typical? It's flying ok, if a little twitchy.

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