Ah, I hadn't thought about using stepper motors (I've never looked into how
difficult the control would be).  Would this package be of any use to you?
 I would assume you could kludge it to work, but I don't know if it really
helps.

I will have to think about the holonomic controller.  (I don't have access
to that paper here, I'll get it later today)  That will be difficult to
debug because I don't have a holonomic robot.  But I suppose I could use
the holonomic controller on a non-holonomic robot, right?

-Jon


On Wed, Feb 20, 2013 at 5:20 AM, Claudio Carbone <cla_carbone@tiscali.it>wrote:

>  Nice work Jon.
> I'll check the code one of these days.
> In my university our diff robots are so small and cheap they have steppers
> rather than encoders
>
> One thing I can think can expand your stack is a holonomic controller:
> lin_spd=cos(robot_theta) *vx+sin(robot_theta)*vy;
> ang_spd=-( 1/d )*sin(robot_theta) *vx+(1/d)*cos(robot_theta)*vy;
>
> d being the distance from the actual drive center (the pivoting point of
> the platform) along the longitudinal axis of the robot (the forward
> movement axis).
> Then going from (lin_spd, ang_spd) to (wheel_1, wheel_2) is trivial.
>
> Relevant article:
> Bilateral Teleoperation of a Formation of Nonholonomic Mobile Robots
> Under Constant Time Delay
> Oscar M. Palafox and Mark W. Spong
> (can't attach here)
>
>
> Best regards
> --
>
> *Eng. Claudio Carbone
> Embedded Systems Design***
> **
>
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>
>
> --
>
> *Eng. Claudio Carbone
> Embedded Systems Design***
> **
>
> P.IVA: 11688471009
> tel: +393809017424
> email: Send email
>  <cla_carbone@tiscali.it>[image: My linkedin profile]<http://it.linkedin.com/in/embeddedesign/en>
>
> My Portfolio****
> [image: My portfolio site] <http://www.fusioncoredesign.it/>****
>
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