ArduCopter 2.8 / 2.8.1 released

Arducopter 2.8.1 is now in the mission planner and in the downloads area! Remember to do your MP configuration again after loading this code, since it erases your EEPROM and sets it to the new defaults. 

Note: Issues with APM1 user's level feature not working are now resolved.  If you installed 2.8 we highly recommend you upgrade to 2.8.1 as 430 extra bytes of RAM have been freed up which reduces the chance of memory corruption (although we haven't seen any cases of this on the APM2 at least) .

Note #2: this release has not gone out for Traditional Helicopters until they can be tested fully.  Flip and Toy mode have also not been fully tested.

Improvements over 2.7.3:

  • Improved ACRO mode (Leonard Hall)
  • Improved stability patch to reduce "climb-on-yaw" problem (Leonard, Rob Lefebvre, Randy)
  • Rate controller targets moved to body frames (yaw control now works properly when copter is inverted) (Leonard/Randy)
  • Less bouncy Stabilize yaw control (Leonard)
  • OpticalFlow sensor support for APM2.5 (Randy)
  • DMP works again by adding "#define DMP_ENABLED ENABLED" to APM_Config.h You can also log DMP vs DCM to the dataflash by adding "#define SECONDARY_DMP_ENABLED ENABLED" (Randy)
  • Watch dog added to shutdown motors if main loop feezes for 2 seconds (Randy)
  • Thrust curve added to linearize pwm->thrust. Removes deadzone found above 90% throttle in most ESC/motors (Randy)
  • More timing improvements (main loop is now tied to MPU6000s interrupt) (Randy)
  • GPS NMEA bug fix (Alexey Kozin)
  • Logging improvements (log I terms, dump all settings at head of dataflash log) (Jason)


Bug Fixes / Parameter changes:

  • fixed skipping of last waypoint (Jason)
  • resolved twitching when no GPS attached (Tridge)
  • fixed loss of altitude if alt hold is engaged before first GPS lock (Randy/Jason)
  • moved Roll-Pitch I terms from Stabilize controllers to Rate controllers
  • TILT_COMPENSATION param tuned for TradHeli (Rob)

Code Cleanup:

  • HAL changes for platform portability (Pat Hickey)
  • Removed INSTANT_PWM (Randy)

As per usual PIDs are optimised for the 3DR/jDrones quad with 850 motors and 10" props. If you're using more powerful motors/props and are seeing bad flight behaviour in stabilize, start by turning down Rate Roll P in 25% steps.

Please note that on this release we've moved the Roll and Pitch I terms from the Stabilize controller to the Rate controller. There's some evidence that says this can lead to flips on take-off if you move the roll or pitch sticks around as you take-off so we recommend you leave these sticks in the middle until you're in the air.

Please feel free to report issues you find in the discussion below and/or add them to the issues list.

Thanks and enjoy!

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  • I loaded the 2.9rc4 software on my tricopter and overall I think it's great.  I've done some tuning now and it's flying well doing basic things.  I'm still learning to tune and would like to get better at it.  I even ran a mission for the first time today - everything worked great.

    The only strange behavior still is during hard flying.  One test I've done is to simply move left and right.  Once I hit a certain speed and reverse direction the copter over controls.  You can actually hear some of the motors all but stop and it's almost 90 degrees in the air - no problem on recovery.  Didn't know if this is a tuning issue where I could make things better.

    The second issue is dropping altitude during fast forward flight.  I don't know what is normal or to be expected.  Going at a moderate rate altitude hold works great.  Fast forward flight is my only problem.  Perhaps this is normal.

    I've attached my settings and the tlog of a test flight.  Hopefully that is the correct data.   For the test flight I did the left right and forward flight test.  At the end I did a RTL with landing to make sure that would work properly.

    Just looking for some suggestions on what parameters to tweak to have a even better flying machine.  I need to learn how to interpret the logs - I'm still learning.  I've made a lot of progress this weekend.

    Thank you!



    2013-01-13 16-45-40.tlog

  • Ahh it's been a while since i spammed this thread...


    Are we sitting comfortably?


    I had a great day today. I've ironed out most of my mechanical niggles and got 2.9 rc4 out for a play.


    I testing everything i could before it got dark, then i tested AUTO :)


    Quick summary:


    APM2.5 mounted on a mix of foam, rubber, silicon and nylon.

    Jdrones 880kv motors (thanks Dany, Hobbyking f30a esc's, simonk firmware. 10*4.7 APC props, ublox GPS, Xbee 2.4s, futaba t7c and r617fs. 4s 4000mah turnigy nanotech. Param file attached.



    Acro - brilliant, very stable, defaults are ideal for a beginner, and can be configured to be very sharp indeed. (Can't wait till we go body frame and we can flip in pitch as well as roll)


    Stabilise - just about perfect, completely confidence inspiring, great fun, just stable as hell, as it should be.


    Alt-hold - i challenge you to find a better one! Just on baro (and acc's) it's sooo responsive, just watch the vid to see what i mean.


    Loiter - great, super stable in low winds, loitering in a 1m box for minutes and minutes.


    RTL - tried 8. Each one would have landed within touching distance if i hadn't stood back to watch. brilliant.


    Auto - well just check these pics out!!!









    And to the video.




    I had a few minor issues, these are as follows...


    Althold - if i fly forward i gradually lose altitude – about 1 metre in every 20.


    Loiter - If i fly around in loiter a gradual drift builds up so that it will no longer hold position, flicking out of loiter and back in rectifies this.


    Auto. If my first command is take off and the second is a way point,  it takes off but doesn’t move to waypoints, it just stays at take off position. Im pretty sure its me doing something wrong though.


    And for your perusal, the logs to go with the video pics and files


    The mode tests are shown in both t-logs

    The auto in the video starts on 78% of the larger t-log.


    The log file contains much of what you see in the video, my probs with auto (not advancing to waypoint after auto-take off), and the night time automission.


    Param file for most of the flights attached. (params look different at the start of the log, but i'd tuned rate_p in flight to get it right) attached.




    Oh and let me know if I'm doing anything wrong. Thanks :)

    all modes test.tlog

    auto in the dark from 78%.tlog

    2013-01-13 20-42 14.log
  • This my tlog test auto mode 2 rounds .

    2013-01-13 18-00-42.tlog

  • Hi,

    I have seen some problems with loiter on RC4.

    I use it on a Arducopter Quad 1.0 frame with "standard" motors and in this case a 2200mAh 3cell battery.

    It gets unstable if I try to move position and then let go of the sticks.

    I use standard PID settings, and I guess they should be ok for this frame (Note I did not erase Eeprom after RC3).




    2013-01-13 16-12

  • I've just tried my hand at uploading a beta firmware release for the first time, and all went well, but...

    After successfully connecting back to MP with usb, and going to the config tab, I get no radio channel input bars at all. When connecting my battery instead of usb, I get the famed no throttle input steady beeps of death from the ESC's..

    Upon re-flashing with the current 2.8.1 in MP all is well again, and I get everything as expected..

    What might I be missing? 2.9-rc4 compiles happily and uploads..



  • Moderator

    Alt hold still jacked on APM1 with RC4 with sonar enabled. Holding quad 1m high with bottom down reports altitude pretty close to 1m. Point quad toward a wall 3m away and altitude shoots to 9m or so. Level the quad again at 1m high causes reported altitude to crash to -3m until it works its way slowly back to 1m. Normal? This instability is reflected in flight. Would anyone like me to try anything?

    With sonar disabled, altitude hold does not shoot up and down like with sonar enabled. It just doesn't work. It's like there is no deadband around hover throttle.

  • Hi,

    A very minor thing in RC4, but very easy to fix. To enable / disable CURRENT in log we have write CUR and not as expected CURRENT. Reported here: Issue 516

    Another thing. Is there a reason for not enabling RAW and MOTORS as default? I think I have seen developers writing that they prefer those enabled. 


  • Hi Randy,

          I just test 2.9 rc4 finish on the evening and sent my logs for looks it

    2013-01-12 18-15 3.log

    2013-01-12 18-14 2.log

    2013-01-12 18-17 4.log
  • Randy,

    Just a question:  Is inertial aided alt hold automatic with v2.9+? I noticed the parameter AHRS_BARO_USE, which is disabled currently on mine.  My guess is that is for something else.

  • Developer

    ArduCopter 2.9-rc4 (release candidate #4) is now in the download area.  Apologies to those people who tested rc3 just yestereday. 


    This release candidates includes just two (important) fixes over rc3:

    1) Smoother transition between manual and auto flight modes
    2) bug fix for LAND not actually landing when initiated from failsafe (RTL worked but if you're very close to your home position when failsafe is activated it goes straight to LAND - it was this situation that was not working properly).


    We are hopeful that this will be the version that will end up in the mission planner in a few days assuming no other issues pop up.


    If anybody's having any issues with this version or -rc1, -rc2 or -rc3 I'm here to help!

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