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 not turn off transmitter. But, It have RTL by itself and auto land on at that time is ok.

Sorry Alexey, you can't.

When you connect both you can't connect the OSD tx. When you just have the OSD you have to connect the tx.

The way to do this easily is when you remove the xbee connection , connect the OSD connection to that one instead of the rx only port.

That is about as simple as I can give you.


Thank you, 

I will do tx with ability to connect to OSD

Today, I test 2.9 rc2 by used GPS MTK3329 removed battery backup again. it's loiter mode very good and hold on the air and test Guided mode very nice and no oscillate. 


No one had problems with optical flow in the actual master repository?

I can´t believe that I am the only one.




     So it works ok with 2.9-rc2 but not on master?  That's very easy to imagine because we've just done a major change (in master) to allow us to port the code to other hardware (especially the PX4).  We're still working the issues out...we hadn't got to optical flow yet so thanks for testing this for us!  We will sort it out.


     With the easy performance monitoring we have in 2.9 (the dataflash PM message includes info on the # of slow running loops) we've stumbled over some performance issues on the APM1.  These issues have actually been there from even before 2.8.1 but in any case, we're working to resolve this before pushing out release candidate #3.  Hopefully won't be more than another 24h or so..

Hi Randy,

Much appreciate the work you guys are doing.

I've "invested" heavily in APM1's, what would the last stable code for them be, both quad and  'plane?



Does anyone have a log screenshot of RAW accel data that shows what vibration levels SHOULD look like?  The reason I ask is because I am not sure I know what "acceptable" level of vibes on this system actually is.  I have a TBS Discovery, which is a great little frame, but has issue with vibes due to the infamous DJI vibro-arms.  Even well balanced props, motors will give some cameras (and maybe controllers) fits.  My APM2 currently sits on 0.25" thick 25duro soborothane, which generally does well.  Though, in this case, the controller is probably too light.

I will post some of my levels tonight, but I thought I would see if anyone has any shots of there levels.  A description of your setup and any iso techniques would be good as well.

I've had vibration issues on a TBS Discovery too - after a few flights today using Moon Gel (, things seem to be better. I used Moon Gel under the APM, and zip-ties to hold the APM to the top of the top plate (will get photos if needed)

It was pretty well tuned before hand, but after flying a while, i'd end up using full direction travel on the stick to keep it level - ended up flying backwards/sideways to get back to me! It now loiters and NAV is pretty good too. I had some good 3M double-sided tape/pads holding it on and it didn't move. Now there's (to me) too much wiggle, but it seems to work...

Intersting, so you are mounting it to the top plate rather than the bottom?  I have some moongel as well that i can try out.

Guys, just a warning.  We've been down this road before with vibration damping systems.  I actually did some very complicated systems, about a year ago, when we had much worse vibe problems.  It's a long, lonely road, and in my experience, goes nowhere.

You're far better off solving the source of the vibrations.  Or just turn the inertial Alt-Hold off.  But if you're having problems with your attitude too, it might be hopeless.

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