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Fig. 16.5. NASA rovers began the robotic exploration of Mars in 2004.
The first Defense Advanced Research Projects Agency (DARPA) Grand
Challenge, held in the United States in 2004, was a competition for driverless
vehicles funded by DARPA. The goal was to successfully navigate a 150-mile
course in the Mojave Desert in California. No team successfully completed
the course in the first Grand Challenge. The vehicle that traveled farthest was
Sandstorm, a converted Humvee built by a research team from Carnegie Mellon
University. Sandstorm covered more than seven miles before it caught fire and
ended up stranded on a rock. No prize was given that year, and the organiz-
ers scheduled a second event a year later. That time, five vehicles finished the
course. The winner was Stanley, built by a team from Stanford University led by
Sebastian Thrun. Stanley completed the course in about seven hours, closely fol-
lowed by two entries from Carnegie Mellon, Sandstorm and Highlander, led by
the roboticist Red Whittaker ( Fig. 16.6 ). In 2007, DARPA organized a third driver-
less car competition, this time on a sixty-mile course called the Urban Challenge
that required driving through inhabited areas. The robotic vehicles had to avoid
other vehicles and obstacles in a crowded urban environment, obeying all traf-
fic regulations. The challenge was won by Tartan Racing, a team from Carnegie
Mellon University, driving a modified Chevy Tahoe SUV named Boss.
The robotic vehicles most in the news are undoubtedly unmanned aerial
vehicles , also called drones ( Fig. 16.7 ). The military increasingly uses drones for
surveillance and battlefield exploration. These military drones are typically
large and expensive. Just as we saw the PC movement emerge from the hobby-
ist community, today we are seeing explosive growth of a low-cost “hobbyist”
drone movement. A key ingredient for a drone is an autopilot. When autopi-
lots were originally introduced in the 1930s, the control systems merely kept
the aircraft level and flying on a preset course. Nowadays, autopilots can be
used to automate the whole flight plan, as well as the takeoff and landing.
What has changed in the last ten years is that all the components needed
to construct an autopilot have become much smaller and cheaper. These
devices include gyroscopes to measure rates of rotation; magnetometers to act
as a digital compass; barometric pressure sensors to determine altitude; and
Fig. 16.6. Carnegie Mellon University's
driverless vehicle Sandstorm competed
in the 2004 and 2005 DARPA Grand
Challenges.
Fig. 16.7. The Northrop Grumman
Global Hawk drone can fly at sixty
thousand feet for flights as long as thirty
hours.
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