🚀 go-pugleaf

From article <19496@ttidca.TTI.COM>, by hollombe@ttidca.TTI.COM (The Polymath):
> In article <J?=%^5|@ads.com> pkenny@ADS.COM (Patrick Kenny) writes:
> 
> }Where do you see the next breakthrough in robotics coming from
> }and how will the acceptance of robots affect our culture.
> 
> The technology is advancing so fast it's hard to decide what's a
> breakthrough.  Six degree of freedom arms are now common.  A year ago they
> were like hen's teeth and outrageously expensive if you could find one.

Sorry, but the PUMA 600 (as it was called then) was available 10
years ago.

> Force sensing is now commonplace.

Force sensing is one thing; force servoing is quite another.  There's
been research in force servoing for over a decade now, but there's
still no industrial robot that offers force servoing as an option.  [So
we at Sandia spend a lot of time figuring out how to get hooks into the
commercial robot's controllers so we can servo tool contact forces.]
Unimation has long offered their "alter" interface which requires an
additional processor between the force sensor and the Unimation
controller to close the force loop around the position loop inside the
controller [that's a mouthful, eh?].  But thru-the-arm tool contact
force servoing at their 28 ms update rate means you can't move very
fast when the tool is in contact.  Adept now offers their Force Sensing
Module which gives the ability to sense, record, and reacte to contact
forces; but not to servo them.  This gives the ability to do "guarded
moves" which is certainly useful.  They had a DARPA funded project to
do thru-the-arm force servoing and developed that capability in their
Force Control System (which we have at Sandia as a beta-test site).
But even at a 250 Hz force servo rate around a 500 Hz inner position
loop, there is still too much bandwidth limitation to perform tasks
like deburring that humans can do relatively easily.  Adept is no
longer working on the FCS since they surveyed industry to see who
wanted force servoing and most responses were negative.  [I think this
is due to the fact that thru-the-arm servoing does still have
limitations and industry knows it.  Why do active sensing and control
for an insertion task when a RCC on a good arm can do it passively?]

> -- 
> The Polymath (aka: Jerry Hollombe, M.A., CDP, aka: hollombe@ttidca.tti.com)

Cliff
-- 
A society is not civilized until it domesticates the icecube.

Cliff Loucks  <=>  loucks@intvax.UUCP
Sandia National Labs, Albuquerque, New Mexico