The static and dynamic performance of a new kind of linear microactuat
ors of 4x4x0.1 mm(3) size is presented, providing large work outputs.
The actuators consist of a stress-optimized active microdevice of a sh
ape memory alloy with one-way effect connected to a biasing device. Th
e biasing device is either a superelastic microspring or a second acti
ve device with opposite actuation direction. For a maximum strain of 1
.3%, strokes of 570 mu m and maximum forces of 110 mN are achieved. Ti
me-resolved experiments with an optical transmission scheme reveal for
a driving power of 190 mW heating and cooling times of 300 ms and 1.5
s, respectively, Considerably shorter switching times down to 50 ms a
re achieved by making use of partial phase transformations. (C) 1998 E
lsevier Science S.A. All rights reserved.