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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Heino, I was talking with Randy and we tested the same thing.  CLI leveling works.  So we can do that for now until we get to the bottom of it.

I also noticed the same thing where the LED's look weird during the GUI level.  My red LED is sort of stuck on dim, which would indicate it's getting an on/off pulse somehow.

Sounds good - I'll continue testing using the CLI level.

CLI level worked here too, thanks

First flight of 2.8 on my Jdrones quad looked good. Default loiter and althold values were not too good for my quad (as in 2.7.3) and I'm adjusting then to what worked will in 2.7.3. 

I think any other issues I had between MP and 2.8 on the APM1 were related to either the MP or APM being in a weird state after trying the GUI level and failing. I'm not seeing any issues as long as I stay away from the MP level and use the CLI.  Thanks!


I think this version is a major step in Arducopter history, because (in my opinion) it's the first time a open source project has a working mpu dmp integration. After the obligatory eeprom clear of my apm2.0 i compiled (with ard. 1.0.1) your 2.8.0 FW with the following parameters and loaded it up:




In Terminal: cleared logs and loaded defaults. Terminal worked like always.

Hardware: APM2.0 (extra BEC 5,4V), Minimosd, 5,8GHZ VTX, FRsky D4FR (sumsignal, higher channels used to low extend), DJI 450 Frame (quadcoter), 4xSkywalker 20 A ESC (@490 Hz PWM), 4xRobbe Roxxy 2827-26 (930KV),4x APC SF 10/4.7(balanced), 3SLipo 3300mAh, Total: ca 1,2Kg

Not tested: GPS, because mag not calibrated yet and no time (it got dark)

Tested: Acro, Stabilize, Althold


Acro: With lowered rate_P 0.120 (like i had to with 2.7.3) and an increased rate_I to 0.100 I finally have a very good Acromode. Normally i fly multiwii for Acro, but moving the "I" authority to the rate controller worked wonders!! Now the apm acromode is how i like it!! Very good!!

Stabilize: No need to change values, flies perfect.

Baro/Althold: Worked good on stockvalues with 2.7.3 and my setup. With 2.8.0 on stockvalues it was not so good (didn't tune) but worked ok.

All modes: No Yaw-Jump anymore - Very nice, but wasn't a big issue with 2.7.3 for me. No glitches or strange flightbehaviour. No wobbles in fast descent. Heading hold worked very good as well.

After all i had a very pleasant and relaxed flight time. Thank you very much for your coding and developing efforts. I would like to know how much cpu power is now free due to the dmp usage.

I noticed one strange value in MP (attached as screenshot). With calibrated acc and the copter standing level next to me the "vertical speed" showed a value of 53.02 ?? Is that normal? EDIT: I am stupid, it is normal, because it is the YAW value........... sorry for missing braincell...

So long

Kraut Rob


Spooky! Right time of year anyway.Despondently twiddling about in Mission Planner and,though not connected to APM,clicked on firmware > load v2.8 quad,the usual run-through load & check completed. Grasping at straws, thought I'd give connect one last try before switching off and getting the  bottle out,ultra freaking hell,it worked!!! That was on USB so I tried via Xbee, you could have knocked me down with an undernourished minnow when that also connected.The bloody gremlins must be having a jamboree here.

Took it out briefly just now - a bit windy out, but it did pretty well.


Re-entered my previous settings except for the I-terms went to Rate instead of Stab.


Feels more responsive in general without being twitchy. Not sure if it is some change in the code or if something upset my sensor, but I had to turn off the Sonar - with it on, I was getting crazy altitude drops in Loiter. With it off, no problem. This was hovering at about 20 feet up, so probably in that zone of crossover between sonar and Baro. But I have pretty much given up on sonar anyway - it is not particularly useful when it works anyway.


Hopefully, we will get a still day soon so I can really get out and fly it and see what happens.

Dumb question - I assume DMP is Digital Motion Processing? What are the benefits?

Thanks Kraut Rob for your test and report!
Nice to read you are happy like me with this milestone release! :-)


Hmmm.... I had trouble connecting APM1.4 via 3DR Radio during the beta testing phase.  USB was fine, but no telemetry.  I was told the issue was fixed.  I haven't tested it yet with 2.8.

I think APM1 people are going to have to be patient until this is sorted out.  You can actually load old firmware versions, if you look down on the bottom right of the Firmware page, you'll see a "Load Old" or something like that.  The top of the list should be 2.7.2 last time I checked.

So please, *report* your problems, so we know what we're looking for, but please be patient while we figure it out.

Yes, milestone was the word i was searching for!

I can't wait to do FPV tomorrow, i will fly the hell out of it that's for sure. Sorry that i am not the gps-test person. I just need gps for my minimosd to show me the way back or do a emergency (video loss) RTL on 30m (above trees). Things i don't need, but love to know i have them if i change my mind: Loiter/Waypoint flying. Things i don't like: Simple mode - my brain gets too twisted then, i always imagine sitting in the cockpit. When i flew my helicopters i was so absorbed with sitting in the nose - i flew fpv without camera.

So long

Kraut Rob

BTW: Haven't been eating Sauerkraut for years.....

Hi Scott!

These mathematics are way over my head but from my understanding it is very time consuming for a cpu to filter (kalman and other "magic") all data of gyro/accelerometer and magnetometer from errors and integrate them into a real flight position/attitude. A cpu is more flexible but a dedicated processor like "DMP" with specialization on this can offload a great deal from the main cpu. I think of it like the modern 3d graphics cards. In theory all images could be done by cpu alone but much slower. A dedicated and specialized GFX processor with reduced capabilities compared to a real cpu can do it so much faster and free time for the main cpu to do other things the specialized GFX processor can't do.

I stand by to be corrected, but that is my amateur point of view.

So long



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