Version 2.5 of the ArduCopter code is now available in the AP Mission Planner and in the downloads area!
The default PIDs are optimized for a 3DR/Jdrones quad with 850 motors and 10" props. If you're using more powerful motors/props, start by turning down Rate Roll P in 25% steps.
While some testers have reported very good flights with the default PIDs, some have reported that this release is a little "sharper" due to the DCM improvements and have found they needed to:
reduce stabilize P by 10% (i.e. 4.5 -> 4.2)
reduce stabilize D by 30% (i.e. 0.15 -> 0.10)
increase rate D from 0 to 0.001
Tuning loiter can be tricky. Refer to the discussions which will appear below for more community feedback on what parameters work best.
Please post your feedback in this discussion. For enhancement requests and bug report, please add them to the arducopter issues list. When possible please include logs (tlog and/or dataflash) and tell us whether you're using APM1 or APM2 and what version of the software you're using (presumably 2.5 but tell us anyway!).
Thanks for this release go to the developers (both in the core team but also those who have provided bug fixes through the issues list) and also the community members who participated in the previous release thread and provided some great detailed information in the form of issue reports and logs which allowed us to nail some bugs!
Good luck Dave, I intend to do the same, it will be interesting to see what the results are?
O.k so I started with the settings from Hans.. Just flying in the spare room 4m x 3m to get a feel for it and its easier than taking the laptop down the field. Using the stab and rate pitch and roll settings my Tri didn`t really like them and kept pulsing intermittantly in hover so it wasn`t very stable, so I changed them back to my settings but increased only the stab pitch and roll P setting from 4.5 to 5.0 as per Hans setting now time to go down the muddy field and try loiter... Will report back in a couple of hours...
Right using Hans`s settings for loiter and waypoints, the loiter is as good as it will get I think? keeps within a couple of meters but the waypoints still need some work, although they are not bad... Well done Hans.
Still cant compare waypoints against google earth though as it`s always 20 miles out! is missing the - sign before the longtitude..
Glad you are also getting in the right direction now in Loiter mode. Hope that Dave C can give some additional pointers to get a even better performance since my tuning is based on a lot of trail and error.
Used his guide for setting up de Tri, but the instructions stopped at the Rate and Stab PID's. Thanks for that by the way Dave. Would be nice to have the same practical instructions that covered the other settings like Loiter and Nav a bit.
Hans why did you set the WP_RADIUS to 100? How does that parameter work and what does it do?
Waypoint radius is used in the flight planner when planning waypoints I think it is measured in meters and can be changed, I am not sure of its exact purpose but I think when it is reached the craft will loiter in that radius for the time delay set??
If that’s true it should be set to 0 for a stationary Loiter? Maybe that’s why it does not stay in one spot?
If its true? I am not sure? but I think it only works in auto mode
If I'm not mistaken, its a treshold value that indicates the distance the quad must be from the WP in order that the next command can be initiated, next waypoint, loiter,.....
I've had chance to play with the tri a bit more, again only rate and stab tuning, but I think I have discovered a really nice way to tune the APM for tri, at least for mine anyway.
I went down the rate_D tuning route - hand testing to begin with
1. IN THE HAND! Zero rate or stab params, adding in rate_d till i got twitches, then adding rate_I till the twitches lessened. then backed off on rate_D a bit
Result, rate_D 0.008, rate_I 0.40
2. IN FLIGHT I then setup a low stab_P (3.500) and started channel 6 tuning rate_P for both acro mode and stab in-flight, then tuned stab_P
Result, rate_P 0.160 stab_p 4.000
3. I thought I'd try a bit of stab_D for good measure and got it to about .25 before things degraded. Nice to be able to use rate_D and stab_d together though.
The most controllable, locked in tri i have ever flown, (MWii, KK, Ardu in my arsenal) Super fast solid decents, locked in vertical climbs, cm perfect stabilised fly abouts, really great.
I can't wait till its light again and I can do you a vid.
In the meantime I attached the params I ended up with. In my opinion, (and that's all it is, I speak from observation rather than deep technical understanding), getting the most out of rate_D requires balanced props and as little vibes to the apm as poss. I flew mine with an unbalanced tail prop to see what happened, you could see the tail and the apm shaking, and the tri would wander accordingly, twitching due to the high rate_D. A bit of tape later and it was vibe free and totally rock solid.
I'm not tuning loiter or nav at the mo, as I'm first trying to understand the code a bit better, you'll be the first to know when I do. Although with these params you will notice that loiter_D is very high - something I'm playing with, probably not recommended ;)
For info, 2.5.5. APM2, 1050kv turnigy motors, 30a turnigy escs, 10*4.5 props, very light alu tri frame (this thing has some serious power which is why I have to lower stab_p a bit!)
Cheers for that. I've just put nx-4008s with Gemfan 11x4.7s on my tri (running 3s for now, will be on 4s next week), so I'll have a go at tuning it according to your guide.
I do love the tri compared to the quad! I'm building a second one that will run a multiwii board with dt750s and 11x4.7s.
Yes, a well tuned tri is very nice to fly, it feels like it has a definite 'forwards' compared to a more symmetrical quad. For info I've only ever used 3s.