Biomedical Engineering Reference
In-Depth Information
Power supply
FIGURE 9.51
An illustrative view of the IPMNC actuator showing a flying machine.
Terminals
D
are connected at their ends to a power supply
H
by the electric wire
E
. As shown, wire
E
connecting terminal
D
to power supply
H
includes an on-off
switch
F
. The IPMNC is packaged in this form for application as a resonant flying
machine. In this configuration, the treated IPMNCs (“muscles”) can flap like a pair
of wings and create a flying machine. “Resonant” means excitation at the resonant
frequency of the membrane, which causes the most violent vibration of the mem-
brane. Each body of mass has a resonant frequency at which it will attain its
maximum displacement when shaken by some input force or power. To obtain large
displacements of the actuator, oscillating signals should be applied at a frequency
close to its body resonant frequency.
Figure 9.52 shows a fabricated large IPMNC actuator strip with a pair of elec-
trodes (terminals) in the middle fixed to the actuator surfaces of top and bottom.
Connecting the circuit to an AC-power source (alternating current signal generator)
can produce oscillating motion of the membrane actuator similar to a hummingbird's
or insect's wing-flap motion. Furthermore, by applying the input voltage signal at
or near the resonant frequency of the wing structure, large deformations can be
obtained that will vibrate the wing structure in a resonant mode.
The wing assembly is preferably encapsulated in a thin elastic membrane to prevent
dehydration of the IPMNC actuator. Also, solid-state polyelectrolytes can be incorporated.
In reality, the possible wake capture mechanism in typical flies is described in
figure 9.53, where nonlinear wing operation is necessary to mimic biological loco-
motion. Therefore, the IPMNCs should be controlled in a similar manner to carry
out such locomotion either actively or passively. Figure 9.54 depicts a flapping wing
system equipped with IPMNCs.
9.4.2.1
Artificial Coral Reefs for Underwater Mine and Moving
Object Detection
Figures 9.55 and 9.56 depict large arrays of IPMNC strips acting like large colonies
of coral reefs. These artificial coral reefs can act like large sensing arrays to detect
any special movement of objects underwater—in particular, mines dropped from the
surface—or even movement of surface objects.
