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Bar-Cohen : Biomimetics: Biologically Inspired Technologies DK3163_c001 Final Proof page 10 21.9.2005 6:40pm

10 Biomimetics: Biologically Inspired Technologies

Figure 1.4 Self-assembly of large numbers of MEMS parts into two- and three-dimensional arrays of engineered
crystals. (Courtesy of Babak Amir Parviz, University of Washington, Seattle, WA.)

biologically inspired characteristic is pursued through the use of self-assembly towards developing
an engineering tool to produce structures, devices, and systems. Progress using self-assembly has
allowed for the guided assembly of micro-devices on substrates and self-assembly of large numbers
of parts into two- and three-dimensional arrays or engineered crystals (Figure 1.4). These methods
are expected to allow the integration of devices from different manufacturing processes (CMOS,
MEMS, micro-optics) into one system, addressing some of the main challenges to manufacturing
that are foreseen in 21st century.

1.5.2 Biologically Inspired Mechanisms
Many mechanisms are attributed to a biological source for their inspiration. Some of these
mechanisms include:

1.5.2.1 Digging as the Gopher and the Crab

Since 1998, the author, his Advanced Technologies Group, and engineers from Cybersonics, Inc.,
have been involved with research and development of sampling techniques for future in situ
exploration of planets in the Universe. The investigated techniques are mostly based on the use
of piezoelectric actuators that drive a penetrator at the sonic-frequency range. Using the mechanism
developed, which they called the Ultrasonic/Sonic Driller/Corer (USDC), deep drills were devel-
oped that was inspired by the gopher and sand-crab with respect to penetrating soil and debris
removal (Bar-Cohen et al., 2001). A piezoelectric actuator induces vibration in the form of a
hammering action and the mechanism consists of a bit that has a diameter that is the same or larger
than the actuator. In the device that emulates the gopher, it is lowered into the produced borehole,
cores the medium, breaks and holds the core, and finally the core is extracted on the surface. This
device can be lowered and raised from the ground surface via cable as shown in Figure 1.5. Analogy
to the biological gopher is that the gopher digs into the ground and removes the loose soil out of the
underground tunnel that it forms, bringing it to the surface.
Another digging device emulates the sand-crab. Like the sand-crab, this device uses mechanical
vibrations on the front surface of the end-effector to travel through particulate media, such as soil
and ground. In this configuration, the device digs and propagates itself through the medium. The
biological crab shakes its body in the sand and thus inserts itself into the sand, as can commonly be