SMA torsion spring actuator mechanism:
In the actuator mechanism, two SMA torsion springs are pre-loaded
by twisting each of them reversely (by 180[deg]).
The rotation takes place when one of the springs is heated (usually by
electric current).
By using Ti-Ni-Cu SMA whose stiffness increases drastically when it is heated,
a large torque can be generated even in small size.
Original 0 degree :
pre-loaded
by twisting
The SMA
keeps a relatively high power/weight ratio
even in micro-scale and thus is more advantageous than conventional electromagnetic motors,
which have limitations in miniaturization since
they become ineffective as its power/weight ratio
decreases significantly in micro-scale.
