Newsgroups: comp.robotics,sci.electronics
Path: cantaloupe.srv.cs.cmu.edu!rochester!udel!news.mathworks.com!europa.eng.gtefsd.com!howland.reston.ans.net!agate!darkstar.UCSC.EDU!news.hal.COM!decwrl!amd!netcomsv!netcomsv!netcom.com!nagle
From: nagle@netcom.com (John Nagle)
Subject: Really BIG linear motor
Message-ID: <nagleCy32qy.LxL@netcom.com>
Summary: These things compete with hydraulics
Keywords: motor linear big
Organization: NETCOM On-line Communication Services (408 261-4700 guest)
Date: Sat, 22 Oct 1994 16:49:46 GMT
Lines: 21
Xref: glinda.oz.cs.cmu.edu comp.robotics:14646 sci.electronics:105476

     Some new, big linear actuators were shown at the Motion Control Show
in San Jose last week. Aura (El Segundo, CA, 310-643-5300) showed a
truly impressive device, a linear actuator with a 32 inch stroke and
a maximum force of 2400 lbs.  It looks like a big hydraulic cylinder,
especially since it's equipped for water cooling.

     More modest models start at 10-30lb force, 0.5" stroke, 3.9lb weight.
Note the high power/weight ratio.  That's continuous; it can be exceeded
by big margins temporarily if you monitor the unit's surface temperature.
The smallest unit is priced around $500, not including controller.

     This is not a ball screw; it's a real linear motor, with cobalt-
neodymium magnets.  The coil is sectioned and commutated, so very long
actuators are possible.  Feedback is with a LVDT sensor (an MLDT
sensor on the biggest models).

     These things are finally getting serious enough to give hydraulics
some competition.  And they have obvious robot applications.

					John Nagle

