DTIC ADA282891: Legged Vehicle for Underwater Mobile Operations | |
by Defense Technical Information Center | |
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This report summarizes technical information gained from | |
an investigation into utilizing SMA actuators as muscle | |
components for the biologically based lobster system to | |
be developed under this project. In order for the SMA | |
actuators to be of value in controlling leg motion of the | |
lobster they must be able to contract and relax in a | |
controlled manner much like muscles. SMA wires made of | |
Nitinol do contract when heated and relax when cooled. | |
The heating mechanism in this application is directly | |
related to current density passed through the wire. If a | |
large number of cycles are required, as in our | |
application, the contraction should be limited to about | |
3%. This can provide a cycle life of millions provided | |
that proper protection from overstressing, overstraining, | |
and overheating are designed into the system. SMA | |
contraction time can be quite fast (0.1 seconds or less) | |
depending on the current pulse amplitude and width. SMA | |
wires are very strong relative to their size. A 4% | |
contraction can exert stresses of 25,000 psi. Control of | |
each actuator requires that current pulses of proper | |
amplitude and duration be applied at the correct times in | |
order to not overheat the wires. Proper control of SMA | |
wires for this application will require sensory feedback | |
Date Published: 2018-03-19 06:03:33 | |
Identifier: DTIC_ADA282891 | |
Item Size: 8891394 | |
Language: english | |
Media Type: texts | |
# Topics | |
DTIC Archive; Jalbert, Jim; MASSA PRO... | |
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