Tutorial on configuring ArduCopter for V-tail copters?

[Chris Anderson]

I know that ArduCopter supports V-Tails copters, although it requires some compile-time config settings. But I can't find a tutorial on what/where to change. 

Can anyone point me to the right settings or instructions for that?

Thanks, 

Chris 

--
Chris Anderson

CEO, 3D Robotics

ch...@3drobotics.com

[Jason Short]

It doesn't support V-tail copters. I wrote a version and a few other have done custom version to get Vtails to work. I think one of them has made it into Master.

Jason

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[Chris Anderson]

Do you remember how the Austin team got theirs going? I don't see it in the GitHub repository (only the plane version shows up in a search)

[Jason Short]

Yes, I wrote that for them.

I thought I saw a VTail mixer get committed 3 weeks ago, but I don't see it right now.

Jason

[Chris Anderson]

I found this Vtail pull request. It says it's been merged to master. Not sure what the process/ETA is for it getting pushed to public. 

-c

[Randy Mackay]

Jason,

 

     We’ve got this pull request that came in 12days ago but I haven’t merged it yet.

             https://github.com/NullVoxPopuli/ardupilot/commit/1c83fc3d527ee9c23311c41041892cce367f0cbb

 

     The changes are pretty straightforward to merge into master.  The special thing appears to be that only the back motors are used for yaw control.  Otherwise it looks pretty normal.

 

     The motor mix looks roughly right in your opinion?

 

-Randy

[Randy Mackay]

Chris, Jason,

 

      Ok, I’ve pulled in that change request into master after modifying it slightly:

1.       Made the motor order the same as our standard X copters.  Our motor order is weird but we intend to fix it eventually and it’s better to be consistent.

2.       There was a typo (I think) in the roll factor for the front right motor

 

     Hopefully it’ll work..

 

-Randy

 

From: drones-...@googlegroups.com [mailto:drones-...@googlegroups.com] On Behalf Of Chris Anderson
Sent: April 14, 2014 1:34 PM
To: drones-discuss
Subject: Re: [drones-discuss] Tutorial on configuring ArduCopter for V-tail copters?

 

I found this Vtail pull request. It says it's been merged to master. Not sure what the process/ETA is for it getting pushed to public. 

 

-c

 

 

[Randy Mackay]

 

      Sorry, I forgot to mention that to try it out you’ll need to be using the latest code from master and you’ll need to set the FRAME parameter to “4”.

 

-Randy

 

From: Randy Mackay [mailto:rmac...@yahoo.com]
Sent: April 14, 2014 3:01 PM
To: 'drones-...@googlegroups.com'
Subject: RE: [drones-discuss] Tutorial on configuring ArduCopter for V-tail copters?

 

Chris, Jason,

 

      Ok, I’ve pulled in that change request into master after modifying it slightly:

1.       Made the motor order the same as our standard X copters.  Our motor order is weird but we intend to fix it eventually and it’s better to be consistent.

2.       There was a typo (I think) in the roll factor for the front right motor

 

     Hopefully it’ll work..

 

-Randy

 

From: drones-...@googlegroups.com [mailto:drones-...@googlegroups.com] On Behalf Of Chris Anderson
Sent: April 14, 2014 1:34 PM
To: drones-discuss
Subject: Re: [drones-discuss] Tutorial on configuring ArduCopter for V-tail copters?

 

I found this Vtail pull request. It says it's been merged to master. Not sure what the process/ETA is for it getting pushed to public. 

 

-c

 

 

[Jason Short]

        add_motor_raw(AP_MOTORS_MOT_3,  0.7071,  0.7071,  0.00, 3); // Front Left

        add_motor_raw(AP_MOTORS_MOT_1, -0.7071,  0.7071,  0.00, 1); // Front Right

        add_motor_raw(AP_MOTORS_MOT_2,  0.0000, -1.0000,  1.00, 2); // Rear  Left

        add_motor_raw(AP_MOTORS_MOT_4, -0.0000, -1.0000, -1.00, 4); // Rear  Right

I think this is what we ended up with.

Jason

[Craig Elder]

Randy would you mind adding Frame type 4 to the frame parameter meta data

http://copter.ardupilot.com/wiki/arducopter-parameters/#Frame_Orientation_X_or_V_ArduCopterFRAME

Thanks

[Randy Mackay]

Craig,

 

     Done!

 

     There’s a slight danger that people will try to start using it before AC3.2 goes out but such is life with our current parameter documentation handling.  If that happens they will end up with the X motor matrix so it might not immediately crash.

 

-Randy

[Craig Elder]

thanks

[Stefan Gofferje]

On 04/14/2014 02:44 AM, Chris Anderson wrote:
> I know that ArduCopter supports V-Tails copters, although it requires
> some compile-time config settings. But I can't find a tutorial on
> what/where to change.
>
> Can anyone point me to the right settings or instructions for that?

Maybe not 100% on topic but should we also write something about CoG and
CoT on a V-tail? Those birds do AFAIK get a bit twitchy if not balanced
well.

If I understand it right, the CoT/CoG shift is calculated like this:

Ts = thrust of a single drive unit
Tf = combined front motors' thrust
Tr = combined rear motors' thrust
Ah = angle of rear props from horizontal plane
Cs = CoT/CoG shift in percent to the front

Tf = 2 * Ts
Tr = 2 * sin(Ah) * Ts
Cs = ((Tf/Tr)-1)*100

-S


--
(o_ Stefan Gofferje | SCLT, MCP, CCSA
//\ Reg'd Linux User #247167 | VCP #2263
V_/_ Heckler & Koch - the original point and click interface