Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!zephyr.ens.tek.com!tektronix!reed!reeder
From: reeder@reed.UUCP (Doug Reeder)
Newsgroups: comp.robotics
Subject: Re: Artificial Muscle Actuators
Message-ID: <16515@reed.UUCP>
Date: 18 Jun 91 06:28:05 GMT
References: <30737@hydra.gatech.EDU> <1991Jun12.084550.21121@agate.berkeley.edu>
Reply-To: reeder@reed.UUCP ()
Distribution: comp.robotics
Organization: Tether Propulsion Division, Institute of Knowledge, Jinx
Lines: 29


In article <30737@hydra.gatech.EDU> jt34@prism.gatech.EDU (THOMPSON,JOHN C) writes:
>Does anyone know of a source for muscular type actuators?
>How about research references on the subject? Thanks

    I have used nitinol alloy wire (shape memory metal).  When you heat it
up, it contracts.  It is easily heated by running current through it.  When
you turn the current off, the heat radiates to the atmosphere and the wire
lengthens.  The wires I used: 
length 100mm
diameter .15mm
resistance 4 ohms
max. wattatge  .8 watts
cooled off in about a second.  I got them from Toki America, the American
barnche of the Toki Corporation several years ago.  I might be able to dig
up their address if someone really needs it. They were selling it under the
trademark name Biometal.

    A complete summary of my reseach results:  It doesn't contract as far or
with as much force as they claim it does. The 10 cm lengths contracted
perhaps 6mm, with about 1 or 2 newtons of force, using perhaps 1 watt of
power.  Their efficiency is therefore about 1%.  (This is all from memory)
The power per unit mass is high.  I spent something like $70 for 12 of these.

-- 
Doug Reeder                                   USENET: ...!tektronix!reed!reeder
Internet: reeder@reed.EDU                     BITNET: reeder@reed.BITNET
I'm looking for a grad school or a job as a research assistant where I can work
on tethers for space propulsion or robotics, in particular, walking machines.