[Robotgroup] Detect the Rink. Re: Drive a Droid proposal

[Bruce Waters]

Vern,
        I suggest a point-of-view shift from detect-the-ropes
to detect-the-rink.   If you place two detectors, one outboard
of each wheel,  you can have the bot naturally turn back into 
the rink without a rink monitor person.   Just "pause" the wheel 
*opposite* the sensor which no longer senses the rink.
As the "guest operator" continues forward, the bot will curve 
back into the rink.   Even if the "guest operator" goes 
backwards, the paused wheel (pls recall: that is the one probably 
still on the rink) will just hold its ground as the bot swivels the 
out-of-bounds wheel back onto the rink.  Also, if neither 
wheel senses the rink then both wheels are "paused" and the 
way-out-of-bounds bot simply stops.  An override to take a
bot out of "rink only mode" could be available for a rink 
monitor administrative person if desired or one could use the
brute-force technique of picking up a way-out-of bounds bot 
and placing it back on the rink.
      A down side to the detect-the-rink approach is that the 
entire rink area (less swivel space) has to be made so the 
sensors can detect the rink and still do not false-positive 
when a bot is out-of-bounds.    
   False negatives (from perhaps a failing sensor) would show
up as a bot on the rink going in tight circles.   With some 
"handed" sensors one might even be able to globally trigger 
left-or-right false negatives and have all the bots act like 
ballroom dancers synchronously twirling CW or CCW to 
delight any bot choreographer or racetrack anarchist.
     A great advantage of detect-the-rink is that the "rink" can 
be any shape including shapes with safety zones.   Some 
interesting shapes might include a "racetrack figure8" or oval
wide enough for bots to pass each other.  Ropes for crowd 
control are orthogonal to robot control with detect-the-rink .  
One could choose to have an inner and an outer oval of ropes 
for a racetrack oval, or just an outer set, or no ropes at all.   
One could even have segmented ropes with gates or holes 
and the ropes could move around off-rink without interfering 
with bot control.  
     
Bruce Waters