ArduCopter 3.0.1 has been released and is now available in the Mission Planner,, GitHub and the new Downloads Area.

Warning #1: Compass calibration and reducing interference is far more important than with 2.9.1b

Warning #2: GPS glitches can cause sudden and aggressive position changes while in loiter mode.  You may wish to reduce the Loiter PID P to 0.5 (from 1.0) to reduce aggressiveness (see image below of where this gain can be found in mission planner).

Warning #3: optical flow is not supported but will be back in the next release (AC-3.0.2 or AC-3.1.0).

Warning #4: loiter turns does not maintain altitude.  This bug will be fixed in AC-3.0.2.

Warning #5: This release has only been lightly tested on Traditional Helicopters.

Improvements over 2.9.1b include:

  • Inertial Navigation for Loiter and Auto meaning much more accurate control (Randy,Leonard,JonathanC)
  • 3D navigation controller follows straight lines in all dimensions between waypoints (Leonard,Randy)

         WPNAV_SPEED, WPNAV_SPEED_UP, WPNAV_SPEED_DN, WPNAV_ACCEL allows configuring speeds and acceleration during missions

  • "compassmot" to compensate for interference on compass from the pdb, motors, ESCs and battery.  (Randy,JonathanC) (Set-up video here)
  • Safety improvements:
    • simple Tin Can shaped Geo Fence
    • pre-arm checks to ensure all calibration has been performed before arming (can be disabled by setting ARMING_CHECK to zero).  (video description here)
    • GPS failsafe - switches to LAND if GPS is lost for 5 seconds
    • stability patch improvements to stop rapid climbs in very overpowered or overtuned copters
  • Circle mode improvements including "panorama" when CIRCLE_RADIUS set to zero (Randy,Leonard)
  • SONAR_GAIN parameter added to allow better tuning of sonar surface tracking
  • CH8 auxiliary switch (same features as CH7)
  • works on PX4 (some minor features still not available) (Tridge,PatH)

How to upgrade:

1. Make sure you are using Mission Planner 1.2.59 or newer (get it here)

2. Click on the MissionPlanner's Hardware, Install Firmware screen.  The version numbers should appear as "ArduCopter-3.0.1", then click the appropriate frame icon and it should upgrade as per usual.

3. Reduce the Loiter and Alt Hold PIDs if you have modified them from the defaults.  The modified PID values for the 3DR frame can be seen in the image below.

Note: Nav parameters have been combined with Loiter so do not be concerned if you can't find them.

4. Although not directly related to this release, if you purchased an APM prior to March of 2013, update your PPM encoder to the latest firmware (instructions here).

5. Try out the new version in stabilize mode first, then alt-hold, then loiter and finally RTL and Auto.

Numerous How-To videos are available:

Special Thanks to MarcoDaveC and the large number of testers on the pre-release thread who put their copters at risk during the extended testing period.  Some of their videos can be found hereherehereherehere and here.  Thanks also to MichaelO for the MP changes required for this release.

All feedback welcome.  Please put your questions, comments (good and bad!) below.

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Hi Louis,

What are you press refresh Params after autotune finish or not? Because, You need press refresh params after autotune finished.

Can you supply a flash log?

Hi Spring,

It works well but is constantly evolving. There is nothing stopping you staying at a version that works for you. (I know I stuck with 2.9.1b for quite a while.

If you want plug and play/pray there are options like DJI. 

Just added my external compass and loaded 3.1 rc5. Seems better in loiter (no toilet bowling - no compasmot) and rtl is solid.

Hi Leonardthall,andBalloon

1- to answer Balloon Yes I had refreshed the parameters in the MP.

2-I have not set parameters any parameters in adv parameters menu , I will redo an auto tune procedure with the proper settings on data log to record then will provide you with the file.

Any other possibility why it's not memorizing the autotune pid's  values like a parameter in MP or the safety switch of the PX4FMU/PX4IO

It's a petty that I can' memorized this because the quadric flies great while after the auto tune procedure 

Many thanks

I use gmail also, but I can not see the poster content. See below the email I did receive on gmail, is just a notification about a new message:
9:21 AM (1 hour ago)
to me
Hello criro1999,

You are receiving this notification because you are watching the forum,
"3.1" at "". This forum has received a new topic since your
last visit, "3.1-rc5 oscillations". You can use the following link to view
the forum, no more notifications will be sent until you visit the forum.

If you no longer wish to watch this forum you can either click the
"Unsubscribe forum" link found in the forum above, or by clicking the
following link:

Thanks, The Management

Please describe changes from 3.0.1 to 3.1-rc5 in ACRO mode.

In 3.0.1 i dont change any presets and i understand copter behavior and i like this fly, but in 3.1-rc5 i don understand new behavior in fly.


I want to modify the 3.1RC5 with my custom angle motors (tbs discovery frame) but when I compile de firmware, I obtain the error: Sketch too big.

How to solve this?

Best Regards.

Copter height oscillations in Alt-Hold (with sonar + baro)

Hi Everyone,

As the line suggests. I am using sonar (XL-EZ0, MB1200) + baro on my APM 2.6.
Using 3.0.1 RC5, I have attached the logs for perusal. "This did not happen before" and happens more with slight winds.

Note: There were slight traces of wind, but this Up-Down movement is very consistent. Goes up and down by same distance everytime.

The only thing that I can think of is 'Thr`Mid' set at 596, which I have tried to vary in earlier tests.

Can somebody have a look and suggest why this happens, from the log?

IMU: Vibrations controlled fantastically on my setup.

SonAlt Vs BarAlt: Reading correct values as it jumps and tries to correct.

ThrIn Vs ThrOut, you can see sudden dips. ThrIn (red) remains constant.

Log attached.



Another for the x650 club ;) . Turnigy 2836 950kv motors. 30A esc, APM 2.5; I'm not auto tune yet, it's a little nervous.


I hope to try Autotune this weekend with an APM 2.6 board.  My 2.5 is not doing to well at the moment. :( 


I have the same problem than you.

hopefully someone can help us :)

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