Newsgroups: comp.robotics
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From: crumley@bell.ecn.purdue.edu (John C. Crumley)
Subject: Re: Basic mechanical questions
Message-ID: <crumley.771270070@bell.ecn.purdue.edu>
Sender: news@noose.ecn.purdue.edu (USENET news)
Organization: Purdue University Engineering Computer Network
References: <derossi-070694212106@magic-macip-63.genmagic.com> <nagleCr37Dx.K8u@netcom.com>
Date: Fri, 10 Jun 1994 17:41:10 GMT
Lines: 33

nagle@netcom.com (John Nagle) writes:

>derossi@genmagic.com (Chris Derossi) writes:
>>Rotation I can do with just about any motor. Speed isn't really
>>that important and I can achieve accuracy by using switches to
>>sense when the arm tower is aligned with each of the seven locations.

>       Continuous position sensing is preferred.  With limit switches,
>you don't get any position indication until you've arrived, so you tend
>to overshoot.  It then matters how fast and which way you're going.

With continuous sensing you could then eliminate one degree of freedom,
or motion.  The arm could rotate in an empty plane (I think in the middle
of the tower's height would be best) and stop in the space between
towers.  Then it could translate up or down until it was next to the
disc it is trying to get.  Finally it would rotate again to move the
gripper around the disc.  If you are confident enough in the positioning
equipment, you would not need the empty plane.

How are you planning on letting go of the cd and placing it in the tray
with a top and bottom surface?

john


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John Crumley
crumley@ecn.purdue.edu
Automation Lab
Engineering Research Center for Intelligent Manufacturing Systems
Purdue University
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