SMA’s Are Strong And Compact

Many different solutions have been proposed for this problem, some include using “muscles” controlled by air pressure, piezoelectric materials, or shape memory alloys. Shape memory alloys mimic human muscles and tendons very well.

SMA’s are strong and compact so that large groups of them can be used for robotic applications, and the motion with which they contract and expand are very smooth creating a life-like movement unavailable in other systems.

Creating human motion using SMA wires is a complex task but a simple explanation is detailed here. For example to create a single direction of movement (like the middle knuckle of your fingers) the setup shown in Figure 1 could be used.

The bias spring shown in the upper portion of the finger would hold the finger straight, stretching the SMA wire, then the SMA wire on the bottom portion of the finger can be heated which will cause it to shorten bending the joint downwards (as in Figure 1). The heating takes place by running an electric current through the wire; the timing and magnitude of this current can be controlled through a computer interface used to manipulate the joint.

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This entry was posted on Tuesday, August 26th, 2008 at 8:47 am and is filed under Hobby Robotics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.