48
G. K. Ananthasuresh
Fig. 24 Four parallel-connection heatuators forming expansion building block (top row) and
contraction building blocks (bottom row)
convection, and radiation effects as well as temperature-dependent properties are
to be accounted for in simulation and design [34]. Both intuition and systematic
optimizations can lead to interesting designs. Shown in Fig. 25 is a planar robotic
platform that uses three arrays of expanding parallel heatuators.
The bent-beam actuator and heatuator building blocks are used in arrays or
in special arrangements. We see them in many actuators that use electrothermal
principle. They are thus ubiquitous—the same principle used in many places.
Fig. 25 A microfabricated
planar platform actuated with
electrothermal expansion
building blocks (adapted
from [12]): by applying
different voltages at the three
anchor pads, the central
problem can be positioned in
the plane. The orientation is
not independently controlled
here as there are only two
independent voltage
differences among the three
pads