andre.g

  • *
  • 23
yaw by differential thrust
« on: April 19, 2017, 11:10:44 am »
is it possible to configure librepilot in order to have yaw by differential thrust of the motors?
I have a flying wing with two motors but no rudder.
thank you

f5soh

  • *****
  • 3772
    • LibrePilot
Re: yaw by differential thrust
« Reply #1 on: April 19, 2017, 11:32:34 am »
yes, can be done adding changes to the mixer table.
Like differential ground vehicles.

Your wing is "elevon" type ?

andre.g

  • *
  • 23
Re: yaw by differential thrust
« Reply #2 on: April 19, 2017, 11:34:08 am »
yes

andre.g

  • *
  • 23
Re: yaw by differential thrust
« Reply #3 on: April 19, 2017, 11:38:39 am »
thank you for the answer, but i'm a newbie so i don't know how to add mix, could you explain?

f5soh

  • *****
  • 3772
    • LibrePilot
Re: yaw by differential thrust
« Reply #4 on: April 19, 2017, 12:01:48 pm »
Follow the wizard and configure as a normal elevon wing.

Import the uav file attached, this change only the mixer table and keep the original config without modifications.

Here is the original elevon wing diagram:



After you imported the "mixer file" you should reboot the board and adjust the min / neutral / max in Output tab, same a the first motor you configured with wizard. (Assuming both Esc are calibrated the same)
Right motor is connected to output4 and left motor to output3, if something wrong you can swap output4 and output3.



Remember if you save the settings while you are in vehicle tab, mixer table will be reverted to normal motor scheme.
Throttle curve reduced to 80% max is normal, this give some room for Yaw stabilization at full Throttle.


« Last Edit: April 19, 2017, 12:05:29 pm by f5soh »

andre.g

  • *
  • 23
Re: yaw by differential thrust
« Reply #5 on: April 19, 2017, 12:22:32 pm »
Thank you very much!

Inviato dal mio ALE-L21 utilizzando Tapatalk


Re: yaw by differential thrust
« Reply #6 on: May 20, 2017, 10:27:53 pm »
Hi,

I'm trying the same, but with a "standard" plane, only Rudder is missing and should be compensated using the two motors. I've tried importing your .uav file, but then i'm also have a "elevon" mix, which I don't need.
I've attached my current mixer as screenshot. Any advices? :)

f5soh

  • *****
  • 3772
    • LibrePilot
Re: yaw by differential thrust
« Reply #7 on: May 20, 2017, 10:33:50 pm »
Assuming motors are connected to output 3 and 4, you miss:

- Curve 1 to 127 for output3 (give Throttle response)
- Yaw value for output3 and output4, should be (3)127, (4)-127 or (3)-127, (4)127 for differential thrust using Yaw

Reduce Throttle curve to 0.8 / 80% max

Re: yaw by differential thrust
« Reply #8 on: May 20, 2017, 11:00:32 pm »
Great! Thank you very much!
Another short question: What does these magic numbers mean? means the exact value 127 just "activated" and everything beside that will be ignored?

 

f5soh

  • *****
  • 3772
    • LibrePilot
Re: yaw by differential thrust
« Reply #9 on: May 20, 2017, 11:05:34 pm »
127 = 100%