leecemb@EA.USL.EDU (11/09/90)
Has anyone ever used or heard of someone who has used memory metals in robots.
They are metals that return to a certain shape after being heated. I read an
article in a magazine about them, I don't remeber all of the specs but they
set up simple machine to show it's possible uses.
They had they wire attached to two poles(+,-) and they had a rubber band
going from the wire to another point (see diagram).
++ ### (memory metal) --
++*********************************--
++ # # --
# #
# #
# # (Rubber Band)
# #
# #
# #
#O#
Whenever the wire is heated it would pull the rubber band; however when the
wire is cool the rubber band would pull the wire.
They also had a demonstration on how two wire could be used to act as a finger
Heating one would cause it to flex one way and heating the other would cause it
to flex the other and heating both would make it bend backwards.
Does anyone have more information about this?mwtilden@watmath.waterloo.edu (M.W.Tilden, Hardware) (11/10/90)
In article <0093F732.C4DCDA20@EA.USL.EDU> leecemb@EA.USL.EDU writes: >Has anyone ever used or heard of someone who has used memory metals in robots. It's called nitenol wire and it comes in several different strengths and deformation abilities. There was a company in New Jersey that sold devices and raw materials using nitenol but they folded about a year ago. Why? Well, I bought their experimenters sample pack and found out that the metal has very poor use-stability. You can reform the metal if you put current through it (ie: heat it up) but too much current actually destroys the memory latice. This wouldn't be so bad but the wire has this property of changing it's resistance based on the amount of stress it's under. High stress areas wind up losing their memory because current builds there in comparison to other low stress, low resistance locations along the wire. Result: useslessness. What's the point of making a robot which cannot handle variable loads wthout destroying it's own muscles? The University of Oxford built the most complex nitenol arm so far but quickly grew frustrated with it because of it's slowness and need for continual re-calibration. Kyocera in Japan had a demonstration of small robots using nitenol wire at a trade show two years ago but conceeded that the stuff needed vast improvements before any serious robotics could be considered. For myself, I had hoped to use the stuff for walking-creature legs but aside from the above, the stuff is also grossely inefficient, so any such creature would not even be capable of lifting it's processor, let alone it's batteries. Anyway, it was a good idea at the time. Maybe will be again. Is all. -- Mark Tilden: _-_-_-__--__--_ /(glitch!) M.F.C.F Hardware Design Lab. -_-___ | \ /\/ U of Waterloo. Ont. Can, N2L-3G1 |__-_-_-| \/ (519) - 885 - 1211 ext.2454, "MY OPINIONS, YOU HEAR!? MINE! MINE! MINE! MINE! MINE! AH HAHAHAHAHAHAHAHAHA!!"
jrv@demon.siemens.com (James R Vallino) (11/10/90)
In article <0093F732.C4DCDA20@EA.USL.EDU> leecemb@EA.USL.EDU writes: >They also had a demonstration on how two wire could be used to act as a finger >Heating one would cause it to flex one way and heating the other would cause it >to flex the other and heating both would make it bend backwards. > >Does anyone have more information about this? I recently saw a video tape of a finger design developed in one of the Japanese industrial labs. Each finger was composed of several hollow channels. By adjusting the air pressure in each of the channels and the relative pressure between the channels you could get the finger to move around in lots of different ways. The video showed several fingers working together handling relatively lightweight objects. When I saw the video and was told how it worked it seemed like a real simple and elegant technique. -- Jim Vallino Siemens Corporate Research, Inc., Princeton, NJ jrv@demon.siemens.com princeton!siemens!demon!jrv (609) 734-3331
cb1p+@andrew.cmu.edu (Chris Beasley) (11/13/90)
Back a couple of years ago one of the professors here at CMU (Mark Freiddman) was pretty excited about the uses of this stuff. I think he went as far as getting some sample pieces of Nytinol (SP?) and cobbing up some experiments. Perhaps he has actually built something interesting in the intervening years. B
hollombe@ttidca.TTI.COM (The Polymath) (11/13/90)
In article <0093F732.C4DCDA20@EA.USL.EDU> leecemb@EA.USL.EDU writes: }Has anyone ever used or heard of someone who has used memory metals in robots. The following is the text of a sheet handed out by Robot World at the Robots and Machine Vision conference, minus some spelling errors and meaningless hype: ========================= DH-101 BIOMETAL ROBOT ARM Presenting the silent, motorless robot with built in programmer, computer link, and rechargeable battery for seven hours of remote operation. The Toki Biometal Arm uses specially developed biometal wires and electronic pulses to produce a noiseless, computer controlled, robotic operation. Bio-metal is a thin wire made of a nickel-titanium alloy which shrinks linearly to its original length when an electrical current is applied. BIOMETAL ARM FEATURES Manual operation -- with an ordinary joystick to control the arm directly. The system controller -- allowing programming directly by reproducing the arm's movements with a "teach in" memory control. computer control -- from the printer interface of an IBM compatible computer. The DH-101 consists of five axes which are controlled by six separate bio-metal wires. The robot movement and joints are designed to compare to those of a human arm, and the control switches are labeled accordingly. ========================= I saw what I think was a miniature demo version of the arm at the show. It was available for ~$500. It was interesting as a curiosity, but didn't appear to have much practical use, IMHO. You can reach Robot World West at: Robot World West 2650 Villa De La Valle Del Mar, CA 92014 (619) 259-7893 and Robot World at: Robot World Cohoes Commons 1225 Jefferson Road Rochester, NY 14623 (716) 427-8050 I have no connection and have never dealt with either. -- The Polymath (aka: Jerry Hollombe, M.A., CDP, aka: hollombe@ttidca.tti.com) Head Robot Wrangler at Citicorp(+)TTI Illegitimis non 3100 Ocean Park Blvd. (213) 450-9111, x2483 Carborundum Santa Monica, CA 90405 {csun | philabs | psivax}!ttidca!hollombe