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 ?
Comments
mixing works great
PID's are tuned, but still need refining when the camera mount and extra weight is added, hopefully today
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
here it is flying on ACM2 with a custom mix - tweaking required !
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
i see my first post is mis leading - ment to say "i need to use APM now" not that I am using APM on it currently, hence need some help with the mixing setup
the picture is wrong, left rear motor is CW , not CCW
the rear motors are around that way so the prop tourque adds to the thrust in the direction you want to go
thanks guys
I built it 70mm wide and 800 long (motor to motor)
motors - RCtimer 750 kv with 10 by 4.5 props
battery 4S 5000 to 12000
the most i have lifted is 3.8kg, i plan it to go to 5, you dont want to go much over that, as in a decent side wind you need alot of reserve thrust
Mix
this is from Copter Control settings, with 127=100%
http://forums.openpilot.org/topic/5689-vtail-octo/
front motors , pitch only, 50% authority
rear motors pitch at 50% and Yaw at 50%
side motors roll only 50%
no need to control individually, and would much rather save the channels, i see no need for it
the hex uses an identical mix/channel count, except the roll needs to be cranked up to 75% authority (maybe even more after todays testing) to compensate for only one motor each side
If you guys are able to do this mix on ACM2 i would be very apreciative
Camera - just need roll comp, pitch comp and pitch mixing with TX input, didnt know it was enabled yet in ACM 2
Been flying the Vtail hexa today, its nice as its a less imposing machine to deal with, smaller and lighter.
But the Vtail 8 is much more stable, the paired roll motors work well and stop any induced yaw when flying sideways ( the hex has induced yaw)
Also check out the VTQ (Vtail Quad) - awesome for FPV and stunt flying, as its CG is closer to the front, it pivots around the front motors nicely https://www.youtube.com/watch?v=vA8MPgPpHI0
Camera mixing - what's your goal? Both pitch and roll outputs are fully stabilized already. By default channel 6 mixes pitch. Roll could easily be mixed as well.