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'm running 2.8.1 and I am having difficulty using the ch6 pid tuning feature. The pot adjusts values during tuning, this is noticeable  but when I refresh parmeters it defaults to the min value set. The pot is about 50% so the min value is not correct.

  • Hi...I just updated my quad w/ APM 2.0 to the new 2.8.1 firmware.  I used DaveC's tuning guide and got the gains dialed in really well in the backyard.  When I powered off to replace the battery, I found that it reset most of the gains back to default. This behavior is repeatable and I have tried reloading the firmware (cleared EEPROM as well) but I can't seem to get it to hold gain settings.

    Has anyone else seen this before or have an idea of something I might be doing wrong?  Thanks.


  • Moderator

    I flew APM1/AC2.8.1 today on an auto mission. At the end of the mission, the copter switched automagically to loiter, and then descended to the ground unexpectedly.  Unfortunately, there was a cattle corral and fence where the mission ended, so it descended into a fence. The 3DR frame held up very well, with only tiny nicks in one of the props (still serviceable) 

    As the copter makes clear to me that it is going to land, I switch modes and gun the throttle but it is too late to stop the "landing" - Video: (when uploaded/processed)

    A question, since I've been focused away from AC lately: 

    - At the end of an auto mission, what is the expected behavior? I expect it to switch to loiter and remain there until told to do something different, or until a failsafe triggers. 

    The log file is attached, if there are any kindly souls out there who want to examine this, help me with a second set of eyes to determine why it descends. I suspect some issue with Alt Hold is at play here, that it should have hovered, thinks it is hovering, but could not, for some reason. Clearly it can maintain altitude, since the entire mission is: stabilize into a hover, switch to auto, flies the mission, switches to loiter on it's own, and immediately begins to descend, I begin flipping switches and powering up, and it "lands". Landed well, though....I was happy about that. 

    Oh, up to 25Mph gusts today, but it flew *very* well, until the very end. 

    2012-12-01 14-53-35.tlog

  • Still had the same bad wobble and nearly flipped over when I loaded 2.8.1 on my hex yesterday when using defaults.

    Also the new version of Mission Planner now has to many drop down menus. See related post link below.  Its also now missing the Pitch channel revers check box.

  • Moderator

    HIL FG simulation for v2.8.1 now doesn't work at all, and the option to pick a previous firmware only allows v2.8.1, all the other options load v2.8.1.

  • Last my test change Altitude by APM Planner

  • I just realize that failsafe_off_event() has been changed and doesn't restore the previous flight mode when radio contact is restored but allows user to override pitch, roll, etc. This got confusing 'cos I thought of being in stabilize mode while i was in some kind of loiter mode (maybe a hybrid residual of RTL) with manual override and also when I cut the throttle, the copter came down slowly but the props never stopped spinning (had to take off the battery). Maybe changing the flight mode once radio was restored could have get it back to normal but the behavior was really odd and I think thet if I lose radio control and I don't get to know it this can be dangerous. So I'd recommend to get back to the failsafe_off_event() implementation as it was in 2.7.4.
  • With INSTANT_PWM removed, would this mean I have to purchase faster ESC's? as they only arm with INSTANT_PWM enabled?

  • It's awfully quiet in here ...

    Must be flying a very good version ;-)

  • whether and attempted to but no luck. as arduino loading gives errors, you must change much.
    # define ACCEL_ALT_HOLD 1
    ArduCopter.cpp: 10719: warning: 'void clear_new_altitude ()' defined but not used
    ArduCopter.cpp: 11045: warning: 'void ReadSCP1000 ()' defined but not used
    ArduCopter.cpp: 452: warning: 'void report_heli ()' Declared 'static' but never defined
    ArduCopter.cpp: 453: warning: 'void report_gyro ()' Declared 'static' but never defined ............................. ......................
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