A micro rotary actuator using shape memory alloys
1988; Elsevier BV; Volume: 15; Issue: 1 Linguagem: Inglês
10.1016/0250-6874(88)85021-2
ISSN1873-3050
AutoresK.J. Gabriel, William S. Trimmer, James Alfred Walker,
Tópico(s)Shape Memory Alloy Transformations
ResumoA thin (100 μm diameter) rod of shape memory alloy (Nitinol)_wire was clamped at two ends under torsional strain and used as a micro, rotary actuator less than 0.04 cm3 in volume. Using three electrical connections (the two ends of the wire and a contact in the middle of the wire), the two halves of the wire were differentially heated, which caused repeatable, continuous and directional angular dflections of the wire about its longitudinal axis. In addition, this configuration allows the shape memory alloy to serve as both the actuating mechanism and the mechanical bias (which restores the deformation in the wire after shape recovery). Thus, the biasing takes place with the activation time constant of the wire and not with the thermal cooling time constant in most previous designs. The present actuator achieves operating bandwidths of approximately 4 Hz, two to three times higher than that of actuators of similar size that rely on bias springs. A micro fluid-valve and a pair of micro-tongs are presented as some applications of such an actuator.
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