After months of testing AC3.1 is finally available in the Mission Planner and GitHub.

Warning #1: If the vehicle is left landed (but armed) while in AltHold or Loiter mode for more than a few seconds, the vehicle may suddenly jump into the air the moment the pilot raises the throttle above zero.  The reason is the baro altitude may fall while the vehicle is sitting on the ground.  In AC3.2 this bug is fixed because we reset the target before take-off.

Warning #2: Motors will spin (slowly) by default as soon as the copter is armed!  You can switch this feature off by setting the MOT_SPIN_ARMED parameter to zero.

Warning #3: if you see "Bad Gyro" on the HUD then you may have a blown 3.3V regulator.  See this thread for details.

Warning #4: if you use a sonar set the SONAR_GAIN parameter to 0.8 or lower

Warning #5: Trad Heli users should now connect their main rotor ESC to APM's RC8 output

Warning #6: Trad Heli BUG causes loss of collective control in ACRO mode if swash type set to flybarred (i.e. not flybarless).  Will be fixed in AC3.2.


The major improvements over AC3.0.1 are (full list here):

1. Pixhawk support (Tridge & PX4 development team)

2. Autotune of Roll and Pitch gains (Leonard/Randy)

3. Drift mode (Jason)

4. Improved Acro (Rob/Leonard) and new Sport mode (Leonard)

5. Arming, Take-off, Land in Loiter or AltHold

6. TradHeli improvements (Rob) including:

a) support for direct drive tail rotors

b) smoother ramp-up of main rotor

c) reduced collective for better control in stabilize mode (STAB_COL_MIN, STAB_COL_MAX params)

7. Support for SingleCopter (Bill King)

8. Performance improvements resolve AltHold troubles for Hexa & Octacopters

9. Safety Improvements:

a) GPS Glitch detection (Randy)

b) Motors spin when armed (Jonathan Challinger)

c) crash detector shuts off motors if copter flipped for 2secs

d) batt failsafe option to RTL instead of LAND, gps failsafe option to trigger AltHold instead of Land

e) more pre-arm checks of inertial nav speed,

10. Bug fixes:

a) optical flow working again (although performance is still not great because not integrated with inertial navigation)

b) ROI working (use DO_SET_ROI command)


How to upgrade:
Click on the MissionPlanner's Initial Setup >> Install Firmware screen.  The version numbers should appear as "ArduCopter-3.1", then click the appropriate frame icon and it should upgrade as per usual.

Special thanks to Marco and the many beta testers on the AC3.0.1 thread who put their copters at risk during the testing of this new version and uncovered many problems so that you don't have to!  Here are some of their videos: loiter in wind, patio sonar, autotune, autotune2, roi, beach, acro, vrbrain, tricopter, train spotting, radio failsafe, the tree, double loiter


If you haven't seen it recently, please check out the ArduCopter wiki.


Feel free to post comments below and we're going to use the new APM Forum for support issues so please post your support requests there.

Views: 151455

Reply to This

Replies to This Discussion

Remember when shielding against E/M fields, you can't just wrap the APM nor the GPS/Compass Combo, depending on where the Magnetometer is located, as the Magnetometer (Compass) must be able to see the earth's mag field or it won't work. The best answer is to move the Magnetometer away from the interference source or in the case of magnetic holders/fasteners, to eliminate them in favor of non-magnetic ones.

Try to lower your D rate both Pitch and roll by 5, start it with pitch.

Are you saying to change the rate values?  I do not understand why, because my stabilize mode is just fine, almost perfect. I start to think that this Alt_Hold issue is affecting a lot more people than just me. I don't remember the firmware version that I have, I think that is 3.1 RC5. I'll try to erase/reset the actual firmware and do a fresh install with the last "stable" firmware available.  

Again, if you could analyze my Tlog I would appreciate (to know if this is from my setup, or some bug in the code).
Thanks again,


edited: actual version - 3.1 (5c6503e2)

for small missions, no problems. 
during long missions, according to 75% of flies away a wrong. 
in the area of ​​strong deviation from maxT. 
could this be a fault of the software? 
after the mission end with RTL no problems
greeting Rainer


Ok, new firmware uploaded (3.1 stable), same behavior :(    Just perfect in stabilized mode but in AltHold does not maintain the altitude at all.  

Help needed please... 

@Babis: not easy to understand what's happend but 99% is related to high vibrations to your board, please look them up using this doc.
The flight mode "Alt-Hold, Loiter, RTL and Auto" use the inertial controller, if there's too much vibrations to the board the results are always bad, is normal.
Have you cover the baro with the sponge?
It's already been repeated many times but I still write, please use APM Forum for all your request, not this thread, thank you!

Please enable the necessary data in the log to check the vibration to your board, fly again and upload here the new log (not the tlog).
Here how to proceed.

thank you Marco for your help ..yes i cover the baro..but i must have enough vibrations ..i didn t check was my fault..and i was hover my quad indoor,,when i chang the mode drift fast forward and left and fild the wall ....thank you again 

Ok, i'm sorry but first check your vibrations, when are inside the safe range you can archive same result shown in my video at the top.

Thank you Marco!   I just did what you told, here is a Log with default + IMU data. 

Waiting for some more help from you,

Thanks, Daniel.


Hi Randy .. I have a question .. When setting up multiple copters .. I use copy paste in my radio settings as I have more than one one machine but same setup just different model names in the radio.. In MP when you do setup of new copter do you have to do radio calibration for each model .. and does the 2nd or 3rd radio calibration done for each setup have any affect on the first setup I did ..i.e ..should I be worried about radio settings (calibration) when i go back to say model 1 to change a flight mode sequence in MP ..Or does the radio calibration setting get stored in the APM board rather than saved in MP so it knows which radio setting is for with which model ?  Hopefully you understand what i am trying to say


The Radio settings are stored into the APM's internal memory. Whenever you connect the USB, the (default or user) settings are loaded from APM's EEPROM memory, to be displayed on the MP. The MP is just a display device, it does not store anything specific for you.

PS: In case you want to use similar settings with two radio models, do the setup of the different Radio models, and save the parameters (Full Parameters list) to file(s). You can just reload these configuration file and load those for the other models, load and write to APM (writes to APM's onboard EEPROM permanent memory). 

Hope this answers your question!

Thanks Shyam 

So just to confirm ... when you do "radio calibration" it stores that info onto the controller you have plugged in at the time ?... So each controller has its own "radio calibration" settings onboard.

Reply to Discussion


© 2020   Created by Chris Anderson.   Powered by

Badges  |  Report an Issue  |  Terms of Service