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Vtail Octocopter

Posted by Mathew Wellington on July 30, 2011 at 12:00am

 

Have had this flying as a prototype for a while using open pilots copter control, now using APM.
She weighs 3.8 kg, with a bit over 10 kg thrust
Control is done with 5 motor channels , the front motors are operated as one, and control pitch, the left and right middles motors are controlled as left and right pairs, so that two more channels, and control roll, and finally the rear motors are operated individually (channels 4 and 5) for pitch and yaw control.
Size wise, motor to motor shes 700 wide and 800 long.

Now what i need to learn is how to enable camera contol on APM 2, and how to do the motor mixing (will modify a hexacopter profile)

https://www.youtube.com/watch?v=dwmYk7MKxi8

 

Can anyone give me a quick guide on how to do the mix and enable camera compensation ?

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Comments

  • F. C. Bearsch September 28, 2014 at 5:12pm
    Did you continue this?
  • Mathew Wellington September 10, 2011 at 12:00pm

    mixing works great

    PID's are tuned, but still need refining when the camera mount and extra weight is added, hopefully today

  • Björn Videnberg September 10, 2011 at 8:24am

    Got it fully tweaked now? how is the mixing working?

  • Mathew Wellington September 6, 2011 at 2:01am

    Ok, heres how i did the mix

     

    I modified a Y6 mix, as it required not alot of work :)


    first, define how much "authority" pitch and roll corrections have my mix has them at 100%, but in some cases you may want less

    int roll_out =  g.rc_1.pwm_out;int pitch_out =  g.rc_2.pwm_out;


    if i wanted for example to have pitch to have 80% authority the code would look like this

    int pitch_out =  g.rc_2.pwm_out * .8 ;


    second step is decide what motors will run from what channelfor me channel 1 = front motor pair, channel 2 = left motor pair, channel 3 = right motor pair, channel 4 = right rear motor(CW yaw) and channel 7= left rear motor (CCW yaw), channels 5 and 6 are skipped as they are used for camera control 


    Now the mixes


    in my example i have the front motors responding to throttle and pitch only, so the code looks like this

    motor_out[CH_1]         =  g.rc_3.radio_out + pitch_out;


    the left two motors are throttle and Roll only

    motor_out[CH_2] =  g.rc_3.radio_out + roll_out;


    the right two motors are throttle and roll also, but this time you need to correct for roll in the other direction, so we put a negative sign in front of the roll term

    motor_out[CH_3] =  g.rc_3.radio_out - roll_out;


    Ok, almost there!


    the rear motors, individually controlled, take care of throttle, pitch (- this time) and Yaw
    first - for throttle and pitch

    motor_out[CH_7]         =  g.rc_3.radio_out - pitch_out;

    motor_out[CH_4]         =  g.rc_3.radio_out - pitch_out;


    and now for yaw

    motor_out[CH_4]        -= g.rc_4.pwm_out;

     motor_out[CH_7]       += g.rc_4.pwm_out;


    hope the above makes sense, remeber this isnt my work, i just bodged it around :)

    Comment

     

  • Björn Videnberg September 2, 2011 at 2:56pm

    Nice :=)

  • Mathew Wellington September 2, 2011 at 2:19pm

    here it is flying on ACM2 with a custom mix - tweaking required !

     

  • Björn Videnberg September 2, 2011 at 10:46am

    I will follow you're blog, so pls update when things happens :=)

  • Björn Videnberg September 2, 2011 at 10:33am

    I asked the guys i in rcgroups about mwc thread about v-tail for that flightcontroller. Quad V-tail is working as far as I understand. 

  • Mathew Wellington September 1, 2011 at 11:34pm

    i have just done the program for AC2 , about to test tomorrow :) had a couple of guys offter to code it, but no matter, think i have it sorted. will share the mix when it works

  • Björn Videnberg September 1, 2011 at 11:06pm

    What have happened with V-tail in AC2 and APM plattform?

This reply was deleted.