[Robotgroup] more about motor controllers

[Robo Al]

On Sat, 2008-04-26 at 22:24 -0700, Gray Mack wrote:
> And while your at it, don't forget an emergency kill
> switch. All robots should have this, an easily
> accessible switch or key or flag that when pulled out
> or switched off prevents all movement of the bot but
> can allow higher brain functions to work. So when
> something goes wrong, you can quickly prevent the bot
> from damaging itself or others.

Gray points out a really significant issue here. As an
earlier post pointed out the dangers of even the RC
controlled robots have:

http://urlenco.de/eebwzd

http://www.flickr.com/photos/ewanspence/2327074994/

You may want to ask our prez about how his leg felt
after boogy bot decided to do its own thing.

I would recommend using controllers that force a pulse
to be present every so often. This will save you from
issues where your BS completely hangs after issuing a
full speed ahead.

Having said that, I've been thinking about taking this a
step further and having a dead-man switch type of safety
system. Power to all moving parts would be controlled by
a remote switch that when not pressed it will cause the
mobile platform to stop on its tracks and apply brakes.
Then a local pull cord will disable the brakes in case
the platform stops in an unsafe position and needs to be
moved manually.

Just my 2 cents.