Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!sdd.hp.com!hplabs!hplabsb!mgsmith From: mgsmith@hplabsb.HP.COM (Michael Smith) Newsgroups: comp.robotics Subject: Re: High Accuracy manipulators Keywords: accuracy, position control vs. force control Message-ID: <5832@hplabsb.HP.COM> Date: 4 Sep 90 16:40:17 GMT References: <1990Aug28.234809.15660@portia.Stanford.EDU> <1990Aug30.014817.8794@portia.Stanford.EDU> <141582@sun.Eng.Sun.COM> <5829@hplabsb.HP.COM> <29067@netnews.upenn.edu> Reply-To: mgsmith@hplabsb.UUCP (Michael Smith) Organization: Hewlett-Packard Labs, Palo Alto, CA Lines: 35 In article <29067@netnews.upenn.edu> ulrich@grip.cis.upenn.edu (Nathan Ulrich) writes: > >But I'm not a pessimist. I think high-accuracy operations can be realized >with current technology and with serial robot manipulators. But not with >precise position control and not with "endpoint" control, but with force >control. This same low-accuracy human manipulation system can locate its >two hands relative to each other in space with enough accuracy to put a >0.9995" peg in a 1.0000" hole. How? By using compliance and force control. >This is better than any robot manipulator can accomplish without huge chamfers >and the use of a RCC (which is passive compliance). > >My opinion only. Now tell me why I'm wrong. > I work for a $10 billion a year company and I have never seen an application where such a peg is put into a hole! Such an application is about as realistic as bin picking or stacking legos. It doesn't matter how well a system does something that is not useful. This is a major contention of mine. I believe that a great deal of robotics research is misdirected. Hey, sure such stuff is fun. My first paper was on bin picking and I have given demonstrations on compliance using a force sensor because it was technically challenging and interesting but subsequently I found that it was misguided. I have never seen force compliance used in an actual application, not because it is unavailable, but because it is not as needed as other technologies. We have been collectively doing research in robotics for many years now and they are still not widely used in manufacturing. Why? Because they are not cost effective and because they have been frequently misapplied. We need to really look at what robots should be used for and then work on the problems that specifically prevent them from being used in those applications. Mike "my favorite project was a robotic bartender" Smith HP Labs