Version 2.5 of the ArduCopter code is now available in the AP Mission Planner and in the downloads area!



  1. The first ArduCopter code release optimized for the APM 2.  Leans and drift should be much reduced or even eliminated for most users.  This was accomplished through a number of core improvements to the DCM implementation by Tridge like this one and this one.
  2. Loiter and waypoint following should be improved due to a D term bug fix, some tuning and the improved DCM performance mentioned above.
  3. On start-up, the yaw heading is updated with first successful mag read (so you should no longer see the slow rotation from north to your actual heading).
  4. Increased output rate to ESCs to 490hz.  This update rate is also user selectable using the new RC_SPEED parameter.
  5. hexa copter stability patch bug fix (should resolve slight flattening when pitching forward and accelerating very rapidly).
  6. improved baro filtering
  7. fix to dataflash logging of Mag heading
  8. addition of H1 swash plate type and bug fix for proactive yaw compensation for collective pitch changes for TradHelis.



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!


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I started in STABILIZE. During the flight I switched to ALT_HOLD.  I flew for a while in alt-hold mode. My wife ordered DOWN and then I switched back to STABILIZE and slowly took down the throttle. During those last seconds of the flight the hexacopter tilted over heavily and went down.



As I mentioned before, the code is, as of 2.5.4, 10m not 20. Changing that value yourself, provided you don't mind compiling (which is pretty straight forward), is one number in one file.

Maybe I'm confused on what you actually want. You keep replying as if the APM2 doesn't offer both modes described in your original image (and that other FCs do). It does.

Looking at the WKM documentation:

Slide X2 channel switch to Home Lock position to fly in home lock when all the following requirements are met:
a) Home point is recorded successfully;
b) 6 or more GPS satellites are found;
c) In GPS Atti. Mode;
d) Multi-rotor is further than 10m away from home point. 


There is no difference between current APM2 behavior and WKM.

Ive been off the thread for a while. When is the next release expected?

The 2.6 merge window closed today, so we're beginning what's probably going to be a week of testing. If that goes well, look for a 2.6 hex push for next weekend. 

So what's the conclusion Marco?  Are your yaw problems gone?

Whats going to be new in 2.6?

@Chris: 2.6 will have:

1) Performance improvements, especially in loiter and navigation

2) Support for MAVLink 1.0

3) Much improved dataflash erase handling, which should ensure that new boards connect immediately via MAVLink rather than having to wait for a long erase cycle. 

4) Other bug fixes, improved safety checks and tuning improvements.

On ArduPlane, the changes are 2,3,and 4, along with a fix for an annoying bug that made elevon setup difficult. 

Awesome, cant wait to get my quad up in the air again!

Loiter worked reasonably well for me even in strong gusty wind. did a better job at holding position than i could!

@Jo: ArduCopter now can offer all the full functional modes for multicopter owners: loiter, rth, autoapproach (not avaiable in other platform) failsafe and super simple mode.
All this mode are tested by me and all the AC Tester Team without a single issue, all the new videos on my youtube channel prove it.
I agree, there are some things to improve but we are working and we are on track.
I use MK and WKM as commercial platforms and are very satisfiedbut ArduCopter now they are reaching, and surpassing in some things.
It's not a race, but we must consider that "we agreed to match" not long ago, and as a "new team" we are making great strides.
With any "modular" platform like AC is not easy to get the perfect setup and configuration, but once you reach a good compromise can achieve excellent results, the real difficulty is that.
With MK you can buy a complete kit and you're sure it will work well, because it has already been tested tens of thousands of times due is a commercial and expensive platform.

Guys,  thought I would post this hear as well, since this thread gets more visibility from the right people :)

In sum,  my GPS no longer gets a fix.  I consistently get 5-7 sats and let it sit for a longgg time and no fix.  CLI GPS test gives no lat, long but it does give alt and sat count.  I am running an APM 2 with 2.5.5.  The GPS used to work, the proof being that I had many loiter flights under my belt.  I am not sure what has changed to cause this, but I am thinking it is hardware.

Is there a GPS hardware "reset" that I can try?  Or any other suggestions?  Everything else seems to work fine on the board.  Should I try a different GPS?

Okay, I'll be patient some more and keep trying to achieve what I want out of the copter.


Can't the 20m circle for super simple mode be narrowed down to something like 10m away?

How do you actually know when the copter is in that circle and whether it is using normal simple mode or super simple mode?  By seeing the reaction of stick input?


Also, about tuning.

If I've read the wiki well, there are 4 main parameters to tune: Rate_P (most important), Stabilize_P, then Rate_I, then Stabilize_I.

The first two are clear to me.  But why do I need to tune Rate_I and Stabilize_I for?

The problem is you sometimes find different explanations about PID's and sometimes you just don't know what they are for.

How should they be tuned if you want soft response, eg. for an AP multicopter.  Smooth reactions but not too sluggish.


I hope I can get my hexa to fly like I want it too soon.

Thanks for your help in advance.

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