A New Kind of Geologist
Meteorites are the only significant source of material from other
planets and asteroids, and therefore are of immense scientific
value. Antarctica's frozen and pristine environment has proven to
be the best place on Earth to harvest meteorite specimens. Due to the lack
of melting and surface erosion keep meteorite falls visible on the
ice surface in pristine condition for thousands of years. Within this section we will describe the robotic technologies that enabled the first discovery of Antarctic meteorites by a robot. Using a novel autonomous control
architecture, specialized science sensing, combined manipulation
and visual servoing, and Bayesian classification; the Nomad robot
found and classified five indigenous meteorites during an
expedition to the remote site of Elephant Moraine in January of
2000. This section of the site overviews Nomad's mechatronic systems,
and details the control architecture that governs the robot's
autonomy and classifier that enables the autonomous
interpretation of scientific data.
Nomad is an unique autonomous field robot with advanced control,
perception and cognition of a planetary rover and the first
robot to exhibit intelligence to explore an extreme polar
environment and automatically classify indigenous rocks. It combines advanced mobility with hierarchical distributed control to safely navigate in unknown environments.
Nomad is equipped with a sophisticated sensor payload
that enables navigation and science. A laser rangefinder is
used to detect obstacles and orientational (roll / pitch / yaw) sensors make
the robot cognizant of potentially dangerous terrain. A high-resolution
color camera detects and studies
rock targets on the ice and snow. A manipulator arm places a
visible-to-near-infrared reflection spectrometer within a
centimeter of a rock face. For precision placement, a camera
mounted on the manipulator's wrist allows the sensor
deployment software to visually servo to a rock. Nomad runs
safeguarded navigation ( path evaluation and driving) and science
( coordination and execution of search functions) autonomy as the two
major software systems. These elements (both hardware and software) are explored with greater detail in this section's subsections.
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