The arducopter tuning guide.
This guide was written at the time of the release of Arducopter 2.8.1 FW. It is a compilation of everything I have gathered from the experts in the field of flight controller tuning. It will help give you an understanding of how to tune any rotor based flight controller, but its specific to Arducopter and this firmware release.
I will update this as necessary, or if you can convince me any of it is incorrect just post below and I’ll update this text.
There is a summary/quick reference at the bottom, so once you’ve read this rather rambling explanation you won’t have to again, other than to check details :D
Tuning your flight controller is essential for a perfect flight. Even a fully stock frame will fly better if you tune. The default params will be close, but your battery or motors might be performing differently, your air maybe ‘thinner’ compared to the developer that last published the default params, so you should tune.
What we are trying to achieve is control. We start to accomplish this by modifying the amount of P, I and D in our control loops. All three react to our stick inputs and the errors created by measurements from our sensors, and all three will help us fly better. If we do not have enough of any of the params the copter will not feel like it’s under control, it will wander about, not resist wind and be hard to fly. Too much of any of the params and the copter will seem to have a mind of its own. It will over-react. At best you will see it oscillate, very fast, not so fast or somewhere in between, depending on which parameter has been overclocked. At worst it will simple flip over on take-off or be very unpredictable in flight.
We need to find a balance. You can tune each param up individually, but one will have an effect on another. Therefore we must tune one, then another, then go back and see if we can retune the first one again, this is the balance.
And this is where we adjust those parameters – Mission planner config page:
Before you start:
- Charge all of your batteries, you are going to need them.
- Check you are using compatible ESC’s, motors etc, some combinations cause problems.
- Balance all of your props (in-situ preferably – adding bits of tape or nail varnish to one side of the prop until the motor and prop don’t shake at all under throttle.
- Do all the other sensible things like check everything over and calibrate your ESC’s , radio compass etc.
- Set your copter up as you will normally be flying it. If you tune it then add or remove weight, or change the CoG, you will have to tune it again. Use your normal flight batteries, a 4s tune will be different to a 3S tune. If you don’t want to risk your expensive camera, just substitute its mass with something less valuable, like a bean bag or kids toy.
- Be prepared to have the chopper in your hand if possible and throttled up (so gloves on, maybe a full face motorbike helmet – that sort of thing, this way you be able to tune quickly and accurately. If you simply can’t hold it in your hand, or a simple jig such as you will see in the videos below – i.e. it’s a gas heli copter/ mad octo then you will just have to do it the long way round – in flight. But read this guide anyway it will speed you right up! (PS helis are not currently supported in 2.8.1, watch this space.
So let’s start tuning
Everything you read below will be demonstrated in the tuning video further down, so you know what to look for, and at the bottom is a summary for quick reference. I think, however, it’s important to include as much information here as possible as anyone starting into this hobby will often find this process to be a bit of a black art.
I’ve found the quickest way to tune the arducopter is to start with rate_D, (but you simply can’t do this unless you can hold your beast in hand or in a jig as the copter won’t fly without any rate_P or I) so a more universal way to start, and actually a more informative way is to start with rate_P.
Since this is about learning for everyone, let’s do it that way. I’ll give a brief low-down on the ‘rate_D’ tune (or Dave C tune, as it’s become known) ‘ later. (BTW, that’s very flattering but I’m only relaying info from the real experts, but hey, if I’m gonna be famous, why not for doing something I love :)) Anyway....
STEP ONE - Tuning rate_P
- Put your copter in ACRO mode,
- Turn rate_D and rate_I to ZERO.
- Set your stab_P to about ZERO, or if you decide to avoid the jig/hand tune and go for immediate in-flight tune set it to about 3.0 as the code is currently using the stab param in acro mode), a true acro mode would not use the stab_P parameter.
- Set a range of rate_P you would like to work with. I’d advise 0.050 or lower to 0.225 the first time you do this as, although you are unlikely to end up near either extreme, you will see what happens at, and beyond, the limits. You will be able to reduce this range as you become more familiar with tuning.
- If you know how to do it, set a pot on your transmitter as channel 6 and use mission planner to set your limits, if you have telemetry this is a joy, if not you are going to be plugging and unplugging your usb quite a bit, it’s not that bad though, and defo worth it.
- OK, time to go, hold copter in hand above head, or place in jig. Throttle up to about hovering point. Wiggle your roll and pitch sticks. With rate_P about 0.075 (unless you have a monster powerful chopper) it will react slowly to your sticks, it will feel relaxed, lazy. If you tried to fly this you’d be chasing it about with your sticks, you’d probably crash if it was nose in, if you know what I mean.
- Slowly turn up rate_P with your pot, or in MP. Move the copter about with your hand and with the sticks as you do so, raise the throttle a bit, lower it a bit, add in more rate_P. It will start to feel and look much tighter in the air, throttle right up and flick your stick the copter should move fast, decisively but then stop quickly and smoothly. If it seems lazy you need more rate_P, if it starts to bounce when you move the sticks or tip the copter about then you have past your limit at this point. Get to a point where you are happy, it feels tight but does not shake.
- Save this rate_P, value, our aim is now to increase it using another parameter – rate_D so on to step two
STEP TWO – Tuning rate_D
- You have found a nice rate_P value (or so you think), so leave that fixed for now. For example 0.110
- Set a range of rate_D from 0.000 to 0.025.
- Throttle up in hand with rate_D at 0.000, things should be as you left them at the end of step one.
- Now start turning up rate_D, again move the sticks, shake the beast about, you will notice that at a fairly precise point you start to see very fast oscillations. This is your maximum rate_D, I’d set it just under where you can induce these fast oscillations by moving the sticks fast of shaking a leg.
- Now you can go back to rate_P and tune that again, you should be able to increase it considerably!!! So to step three.
NOTE: once you have found your rate_D you can try something interesting - you will have to hold onto your bird for this obviously. Set rate_P to zero, then crank up your rate_D as you just have. You will discover that these fast oscillations occur at pretty much the same level of rate_D, no matter what you have set rate_P to. This is why I think it’s more than possible to start tuning rate_D then move on to P. But that’s a shortcut, and this is not what this guide is all about.
STEP THREE – Tuning rate_P even more
- You have your maximum rate_D set, now try increasing rate_P again.
- You should be able to add at least 30%, maybe more before you get the oscillations. It will react faster to stick movement, be difficult to move with your hand and just feel very solid in the air.
Congratulations, your copter should be flying better than it ever has done before.
- Using your ‘happy’ rate_P and rate_D values, start tuning rate_I. This is better done in-flight and will feature in part two of this guide. Basically just keep tuning it up until you notice a loss of ‘feel’. It will hold an angle better for you, unless it’s too high then things go sluggish and eventually oscillate slowly.
STEP FIVE - HEAD OUTSIDE!!!
For now set Stab_P at 3.0 - 3.5, closer to 3.0 if you have a high power machine, just to get you flying in stab mode. Then spend your time tuning rate_I and stab_P.
If you find your set up immediately too harsh, back off on rate_P and rate_D by 10% each, and try a lower i-term, if it's still too harsh do that again!
All that’s left is to watch the video below so you can see what I’m describing and head outside for fine tuning. Oh, and await part two of the guide and amendments from any discussions raised, then we will have a proper tuning guide that will be integrated into the wiki advanced tuning guide :D
Results for tuning in this video were
Oh and as promised, below is Part One of the Summary Guide. I aim this to be on one sheet of A4 and tell you everything you need know ‘in the field’.
- Tune up just rate_P
- Tune up rate_D
- Tune up rate_P more
- Tune rate_I as best you can
- Take it outside with a stab_p of 3.0ish and tune rate_I and stab_p in flight, to your liking, maybe adjusting the other params too slightly, to get it just as you want it.
Summary of what you are looking for
Too much rate P will oscillate quickly, and cause to copter to sound angry under stick input, bouncing rather than smoothly following your inputs. It will also shake more at full throttle and under hard turning.
Not enough you will not feel like you have full control. It will feel sloppy and be very easy to over correct with your inputs. It will feel delayed.
Perfect is where it feels locked in, stiff in the air, but not shaky. (although if I’m sport flying I turn it up a bit for maximum ‘wang’ and just tolerate the slight oscillations)
Too much rate_I will oscillate if you get high enough (a much slower oscillation than a rate_P shake). But quite a long while before it oscillates it will have other detrimental effects on flight performance, like a sluggish feeling or a tendancy to flip over on take-off. This is why I suggest tuning this in flight rather than in your hand/jig.
Not enough will cause the copter to get pushed by a constant wind, then it will fight back using just P. It will not hold a very firm angle during forward flight and will need more correction. This will not be as smooth as it could be in either case.
The perfect amount will cause the copter to lean gracefully into a constant wind, but also allow you to set a lean angle and stay there as you fly about. As you dial rate_i in pay close attention to the feel of the copter, you are not looking to create oscillations here at all, you should notice a strange ‘feel’ long before this point.
Too much rate_D will oscillate very fast, you will see a twitch forming then a fast buzzing oscillation
Not enough rate_D will simply mean you can’t dial enough rate_P and so you will suffer the effects of having rate_P too low.
A perfect rate_D will help fight the wind and follow your sticks as its fast to react, but will also allow you to reach a maximum rate_P level for you frame, thus giving better control.
Does anyone know of a guide on tuning by looking at the logs? I've seen reference to it here and there about comparing the tracking of roll and pitch but is there a guide on what to look for and what to adjust?
Would be great if there was a program that could analyze the flash logs and suggest changes in PID or other parameters. All the info is there. It could even point out problems like a motor working harder than others or a frame imbalance.
What is the best configuration of arduino?
I had some problems with my flights.
My setup is:
Tarot fy650 quadcopter
Turnigy multistar 390kv
Hobbyking 30amp esc with simonk firmware(latest version)
turnigy wooden props 15x4.5
4s nanotech 4000mah battery
I'm having trouble calibrating the pids and i think my quad is not tracking well enough:
Also my pid setting are:
maybe a stupid question, but is there a way to configure the throttle stick less sensitive? what i am looking for is a way to adjust and hold altitude in a better way. once reaching the point where my copter hovers, a small little change on the throttle stick makes it ascend or descend immediatly.
Would be great to have some sort of dead band similar it is the case on alt-hold/loiter.
Is the only way to configure an expo-curve around the hover point on the transmitter?
I just built a quad with bumblebee frame, stock outrunners and an APM 2.5 running arducopter 2.9.1b
Took her for a test flight yesterday in stabilize mode (quite breezy day) and apart from a little drifting, performance was outstanding for out of the box test.
Only problem was landing, as soon as I spool down the motors and get 4-5 inches off the ground the APM kicks in and takes it up a few feet making a soft landing difficult. I broke about 3 skids but fortunately my eldest is a fan of archery and his 6mm carbon fibre arrow shafts make a perfect replacement.. (till he finds out)
Anyhow I noticed that you recommended taking the rate_I down to 0 and then tweak the sweet spot..
In MP 1.2.55 the PIDS have a rate_I for pitch, yaw, roll, loiter and throttle_accel.
I'm assuming that the rate_I to change in this case is the throttle_accel..
Forgive me if this is a dumb question i'm pretty new to this..
Thanks for all your tutorials and help here it never fails to amaze me just how far the open source community goes on empty..
thank you so much for your guide.
it helped me a lot to get my copters much more stable than I ever thought they might get.
however, i still experience some little problem i could not get rid of so far:
when being in loiter or alt-hold mode and hovering around the copter is loosing altitude.
once i keep it in place it compensates that loss and goes back to the original alt again.
seems that the APM does not take use of enough throttle to compensate loss in altitude while moving around.
does anyone have a hint for me, how to solve that?
thanks a lot and best regards from vienna,
Dear Friends, I am having a problem tuning PID trought channel 6, the issue is for example setting min as 0.0700 and max of 0.1400 when I turn the pot of my 9cap it just chooses max or min value, shouldn't it go between those values as I turn it? How can I change that?
THANK YOU! :)
I need some assistance on tuning the 2.5 Arduccopter. It is mounted on on a DJI quad frame.
I went through the tuning as listed. Actually did it two times and got comparable readings both times.
I went out to do the rate_i tuning in stab mode. As I added some power, it lifted off then suddenly went up to about 8 feet and flipped. It was right at the ground when it completed the flip.
I had a similar experience a week ago. I loaded the params file for the DJI quad and decided to give it a preliminary test. I was able to fly it although it needed tuning. Suddenly it went up about 15 feet held for a couple of seconds and then tumbled to the ground.
I have setup a Naza-M with GPS and a couple of KK2.0 boards on quad-, hex-, and octo- copters. I am really excited about the options on the Arducopter 2.5 (from 3DRobotics) but so far, the results of trying to get this in the air has not been good.
I do have the upgrade GPS and using telemetry.
Any help before I try this again would be welcome.
I apologize if it has already been covered but when I use channel 6 to tune the pids, the turning of the knob works great but when I refresh the parameters it always saves whatever I had in the min field as the parameter value.
Anyone else found this or have a suggestion?