APM Copter 2.9.1.b has been released


APM Copter 2.9.1.b has been released to the Mission Planner and is also posted in the downloads area.
2.9.1b is a maintenance release incorporating changes to 4 default parameters that have been optimized since 2.9.1 was released.  There are also 4 minor bug fixes.  There are no code function changes or additional features.
The changes are:
1) reduce default INS_MPU6K_FILTER to 20hz
2) reduce InertialNav Z-axis time constant to 5 (was 7)
3) increased max InertialNav accel correction to 3 m/s (was 1m/s)
4) reduce yaw_rate P default to 0.20 (was 0.25)
5) bug fix for alt_hold being passed as int16_t to get_throttle_althold_with_slew which might have caused problems if you climbed over 320m.
6) bug fix for throttle after acro flip (was being kept at min throttle if pilot switched out of ACRO mode while inverted)
7) bug fix to acro trainer to do with roll correction 
8) prevent cli from being entered more than 20seconds after reboot.
Users are recommended to:
    Update Mission Planner to 1.2.41 and
    Update their flight code to 2.9.1b from the Firmware tab on Mission Planner. There is no need to go through a new configuration process in the Mission Planner.


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  • Testing ArduCopter 3,1-rc2 Loiter in hot strong gusty winds with turbulence from surrounding tall trees, minimal PID tuning, good vibration isolation, compassmot and GPS antenna location, couldn't ask for more, liked it so much I did 2 flights over 10 minutes each waiting for the stronger gusts.


  • I use the latest version of Mission Planner 1.2.59. Can't at all see COMPASSMOT in the setup in CLI.

    Can someone please help?? 


  • Hi

    What do you think about this axel Z? 




  • Dear experts and developers, can you explain that was wrong during the flight

    This is my video

    This is the log 

    2013-05-28 20-02-07.rlog

  • Developer

    I've started an AC3.0 discussion here so let's move our AC3.0 discussions over there.

    We are doing the upgrade more gently this time around.  AC-2.9.1b will remain the default version pushed out by the mission planner for the next month or so but we're encouraging people to upgrade to 3.0 via the Mission Planner's Beta firmwares link.

    I really want to thank all the people who have helped us test the various AC3.0 release candidates.  I think we've saved the wider community a lot of trouble through your efforts and some copter sacrifice.

  • T3

    Hiya- I know this is an old question, but what is the best way to disable the "yaw towards next waypoint" behavior?  I'd rather maintain a consistent yaw, because my copter is used for mapping "lawnmower" style, and I feel that it is wasting some energy yawing at each of the many 90 degree turns on its flight paths.  I'd rather not compile custom code if I can avoid it. Thanks for your help!

  • Hi,

    i built my second octocopter as a coaxial octo. This time i carefully selected props and motors for high efficiency, Now i like to use the "motor top bottom ratio function" (mot_tb_ratio) to minimize inefficiency due to the coaxial setup. The function is not used in 2.9

    How can i activate this feature and are there any problems related to this?

  • Default PIDs and Setting...

    I have a suggestion for documentation and for the first post of a new release like when R3 will become an official release. It would be nice to have a print screen of the "default"  PIDs and access to a param file. That would make the information easy to refer to when we mess up our PIDs or when we change the wrong parameter in the advance settings.

  • I need to manually compile & upload my firmware because I use U4EAKE's code for my LED strips which run off the relay, but I'm getting a compile error.  I do recall someone saying a while ago that you need to specify which board and configuration you are using for it to work.  I have a quadcopter in X conf with APM 1.4 board.  I've tried both version 1.0.1 and 1.0.3 of Arduino but I get the same error output.  Any guidence will be greatly appreciated...

    In file included from ArduCopter.pde:111:
    /config.h:48:2: error: #error CONFIG_HAL_BOARD must be defined to build ArduCopter
    ArduCopter:379: error: new declaration 'uint8_t digitalRead(uint8_t)'
    C:\Program Files (x86)\ArduPilot-Arduino-1.0.3-windows\hardware\arduino\cores\arduino/Arduino.h:100: error: ambiguates old declaration 'int digitalRead(uint8_t)'
    ArduCopter:2191: error: expected constructor, destructor, or type conversion before 'int'
    ArduCopter.pde: In function 'int SKETCH_MAIN(int, char* const*)':
    ArduCopter:2191: error: 'OK' was not declared in this scope
    UserCode.pde: In function 'void userhook_MediumLoop()':
    UserCode:51: error: 'rl_state' was not declared in this scope
    UserCode:60: error: 'rl_counter' was not declared in this scope
    UserCode:66: error: 'rl_state' was not declared in this scope
    UserCode:83: error: 'rl_counter' was not declared in this scope
    UserCode:89: error: 'rl_state' was not declared in this scope
    UserCode:107: error: 'rl_state' was not declared in this scope
    compat.pde: In function 'uint8_t digitalRead(uint8_t)':
    compat:33: error: new declaration 'uint8_t digitalRead(uint8_t)'
    C:\Program Files (x86)\ArduPilot-Arduino-1.0.3-windows\hardware\arduino\cores\arduino/Arduino.h:100: error: ambiguates old declaration 'int digitalRead(uint8_t)'

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