Hi Christopher,

we have been working on sorting strategies with smart surfaces for some
time now.  Check out our '96 and '97 ICRA papers, or the January-March
issue of "IEEE Computer Science and Engineering", there we show some
strategies on how to separate parts (without sensor feedback) based on
part size.  This is also explained in our web site at
http://www.cs.cornell.edu/home/karl/MicroManipulation

Motion planning with multiple objects has been investigated by several
robotics researchers.  Latombe's book on robot motion planning has a good
overview on this area.

Regards,
Karl Bohringer
Postdoctoral Researcher, UC Berkeley

PS: Some references in bibtex format...

@article{BDmDKS97a,
        author = "Karl-Friedrich B{\"o}hringer and Bruce R. Donald and
Noel C. MacDonald and Gregory T. A. Kovacs and John W. Suh",
        title = "Computational Methods for Design and Control of {MEMS}
Micromanipulator Arrays",
        journal = "Computer Science and Engineering",
        year = 1997,
        month = "January -- March",
        pages = "17 -- 29",
}

@inproceedings{BohringerSuhDonaldKovacs97a,
        author = "Karl-Friedrich B{\"o}hringer and John W. Suh and Bruce
R. Donald and G. T. A. Kovacs",
        title = "Vector Fields for Task-level Distributed Manipulation:
                Experiments with Organic Micro Actuator Arrays",
        booktitle = ICRA,
        year = 1997,
        month = Apr,
        day = "20 -- 25",
        pages = "1779 -- 1786",
        address = "Albuquerque, New Mexico",
}

@INPROCEEDINGS{BohringerDonaldMacDonald96b,
        author = "Karl-Friedrich B{\"o}hringer and Bruce R. Donald and
Noel C. MacDonald",
        title = " What Programmable Vector Fields Can (and Cannot) Do:
                 Vector Field Algorithms for {MEMS} Arrays and
                 Vibratory Parts Feeders",
        booktitle = ICRA,
        year = 1996,
        month = Apr,
        day = "22--28",
        pages = "822--829",
        address = "Minneapolis, MN",
        note = "\ifURL{{\tt \URLhome/MicroManipulation}}\fi",
}


On Wed, 1 Oct 1997, The MEMS
Lists Manager wrote:

>
> ------- Forwarded Message
>
> Date:    Wed, 01 Oct 1997 01:26:42 -0700
> From:    "Christopher J. Phoenix" 
> To:      info-mems
> Subject: Smart surfaces--algorithms?
>
> I'm contributing to a paper that involves a transport system with many tiny
> actuators, similar to your smart surfaces.  We're looking at how to avoid
> traffic jams from moving many small parts at once.  Ultimately we'd like to
> be able to perform a sorting function, where the actuators detect the type
> of part and decide locally what direction it should go in; but I suspect
> that this will cause traffic jams or even gridlock, if the parts get too
> congested on the surface.
>
> Have you done any research on decentralized path planning for many parts on
> a smart surface?  Do you know anyone who has?  I'm looking for an algorithm
> that clearly eliminates the danger of gridlock with crossing streams of
> parts, or anything similar that might be a good starting point.
>
> Thanks,
> Chris
> - --
> Chris Phoenix   cphoenix@best.com
> Work (Reading Research Council): 650-692-8990;    Home/voicemail: 415-860-1536
>
>
> ------- End of Forwarded Message
>
>
>