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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  • Hi!

    I had trouble with the calibration of my self build voltage devider ("Pin2") and the Missionplanner (i think 1.2.14(??) - 1.2.17).

    I entered the measured values as always and the MP generates a wacky divider (& voltage). I solved the problem by typing in the values and the divider directly into the MP parameterlist. It's just an inconvenience i didn't have with the older MP versions. So not a problem with the 2.8.1 FW just an MP issue. I also tried - on purpose - to irritate the barocode and i was partly successful :)! I armed the copter in the warm house (20C), ran out in the cold (5C), started the copter without gps fix (blinking) and turned on althold. The copter started to climb ca 1.5m :). I also expected the gyro/acc to dislike the temp. difference but they did well. When arming outside althold works well(even without gps fix). Hihi, at least found something in 2.8.1!! I only managed to do it one time, so i am not shure if it was the temp difference (normally the readout is temp. compensated) or something else - but i will do my best to provoke problems! I also tried to produce the issue of turning out the transmitter after landing with a preprogrammed failsafe in my FrskyRX (modeswitch to RTL, throttlestick to hoverposition, ail/nick to neutral position). As expected the copter wanted to do a RTL at 30m (i set it to 30m to avoid trees). That is not an APM or software issue, because it did what it was supposed to do (of course i held it down by hand).

    I imagine this issue can occur when you landed and lift the still powered copter (to unpower it on a table or so without crawling on the floor) with one hand and holding the TX in the other and "pulling some strings" with your jacket. That is described in the wiki "Don't pick up the model and the radio at the same time, you may bump the throttle." So what can be done about it? First of all everybody should be (and probably is) aware of dangers of RC stuff in general. (A careless friend of mine accidently "launched" a 500 Heli in the livingroom with futaba failsave - he jumped out and re-entered when there was no noise anymore..... luckily no one harmed but renovation necessary). Without sonar or contacts in the landing legs or some other kind of sensor it is not so easy for the copter to find out fast: "the throttlestick is down because i have landed and i can disarm now". For the moment i see some possible solutions:

    A.: Get used to always disarm your copter immediately after landing (thr dwn, yaw left).

    B.: Shorter time till the copter disarms itself after throttle cut. Currently it's about 10 sec. I think 5 sec would do it. I think this parameter is accessible in the MP - parameterlist - sorry haven't searched or wiki-ed for it.

    C.: Put a powerswitch for your apm on top of your copter so you can turn off the electronic when bending down. I think this is the worst idea - and another point of a possible failure.

    I have another question. There is a discussion currently going on in "my" german forum about gimbal stabilization. I have no experience with gimbals in any way. On the MP i see a lot of gimbal options. The people in the forum want to film a snowboardride with their multicopter. One is piloting and the other one (probably with another transmitter or trainercable) should point the camera to the object. They want stabilization in all 3 axes. Can this be done with the current software? From my understanding using apm2 for flying and camera stuff with 3 axes you would run out of traditional RC - channels and require some dataradio setup (laptop/joystick). Is it possible to setup the apm as gimbal only - or trick it into it by defining it as heli with 90 degree swashplate?

    Thank you very much for reading, and sorry for my long post.

    So long

    Kraut Rob

  • I'm a bit puzzled, but not done debugging yet, but could use some pointers. Maybe I changed too many parameters at the same time:

    - Installed cool led strips: where I can find the meaning of the led_mode parameter in the Mission Planner? Default is 9. 

    - When I power the led strips, which also supplies power to MinimOSD, my 3DR modem will not connect. The led strips work fine, the MinimOSD work, but the 3DR modem does not work. If I do not power the LED strips and MinimOSD, then the 3DR modem works fine. 

    - I also built an Antenna tracker based on Maestro: when I use the trim, everything moves as desired and within the specified limits, but does nothing on tilt when bench testing (in a close small space)

    Again: Maybe I'm lazy: I still have lots of debugging to do, and did not go outdoors yet, but some pointers would be useful at this point. 

  • As promissed, today I filmed my flight test. Most relevant part is the Auto flight with about 500mts flight path (doesn't seem too much, but it can make you hold your breath for a while). There was some stormy weather, with wind but luckilly no rain at the time, wich allowed for a great flight under stressfull conditions. There are 9 wayppoints, some at 10mts, one at 15mts, and the others at 25mts high. 2 waypoints with 40 second Loiter, and it behaved flawlessly !!! Great job team :D Then some stunts and stability tests. I'm using an APM1+Oilpan+Lea 6H gps. An old but very reliable platform that has been with me for about 2 years now. Even tough the baro is not the high accuracy one, it still provides some very good Alt hold.

  • Got some more tuning time today, My OCTO lifts at 40% throttle so is slightly overpowered without the camera. After tuning today I've reduced Rate_P to 0.130  rate_i 0.030 and rate_d to 0.004. I've left Imax at default.

    At one stage I had sudden spikes in one of the motors, this was when Rate_i was set to 0.05, its gone now and I've got a very flyable machine although it has been a calm day and I've yet to test in wind. Fast climbs are great but the descent is very wobbly almost out of control so I want to increase my Rate_p but I'm afraid this will upset normal flight.

  • hi

    im try to connect allegro acs756 Hall effect current sensor +-100A to apm2.0 after setting amp_per_volt =  40

    in mission planner i can see 100А value when real current is 0

    this sensor measure both charge and discharge and have zero point at 2,5volt output

    how to change arducopter offset for current measurement?


  • Bonjour  à tous 

    trop content des efforts de  Randy et de l'équipe j'ai voulu joué un peu  comme Marco ( la casquette et le savoir faire en moins !)

    voici le résultat vidéo 1er montage GOPRO sur arducopter trop COOL 


  • I thought I read it somewhere but now I can't find it...what do I change to speed up yaw?  Rate Yaw PI?

  • Im eventually going to get time today to test 2.8.1 on my QC.  I've got a APM 1.4 board with MB1200 sonar, UBLOX GPS, XBEE 900mhz telemetry, 11x4.7 props and LED strips under the arms which work of the relay with U4EAKEs code.  Im running 924kv motors with 25amp ESCs and a 3000mah LiPo.  Even after reading all the documentation about tuning PIDs Im still not 100% sure what process to follow and what exactly to look out for.  Randy states above to turn down the Rate Roll P by 25% if you see bad flight behaviours.  What exactly would bad flight behaviours be???  I dont really get much time to fly or test a version number, and just when I think Im getting somewhere a new version comes out... LOL   Below is a pic of my pride & joy... :-)


  • Whoo-Hoo! ROI works perfectly! Seems a bit more wobbly in Auto mode though.

    Think I ran out of battery at the end. *sigh*

  • Arducopter 2.8.1 compiled with # define RECEIVER_RSSI_PIN 6
    I sent the APM 2.0 and does not work rssi
    something else to do

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