Friday, September 12, 2008

A look at the DARPA Grand Challenge

The DARPA Grand Challenge is an autonomous vehicle research and development program with the goal of developing technology that will keep warfighters off the battlefield and out of harm’s way. The Urban Challenge features autonomous ground vehicles maneuvering in a mock city environment, executing simulated military supply missions while merging into moving traffic, navigating traffic circles, negotiating busy intersections, and avoiding obstacles. While it has military purposes the program reminds me of Brad Templeton's ideas of robotic vehicles for use by regular people in regular cities.

An autonomous ground vehicle is a vehicle that navigates and drives entirely on its own with no human driver and no remote control. Through the use of various sensors and positioning systems, the vehicle determines all the characteristics of its environment required to enable it to carry out the task it has been assigned. The National Defense Authorization Act for Fiscal Year 2001, Public Law 106-398, Congress mandated in Section 220 that “It shall be a goal of the Armed Forces to achieve the fielding of unmanned, remotely controlled technology such that… by 2015, one-third of the operational ground combat vehicles are unmanned.

Clearly this stems from American unwillingness to send troops into harms way. We tend to rely on bombing even though bombs dropped from airplanes are difficult to accurately target and result in collateral damage. Just ask the Chinese whose Yugoslavian embassy was bombed (supposedly accidentally) by U.S. forces, and think about all the accidental bombings of innocent civilians in Afghanistan and Iraq the last few years. It would seem that using robotic military vehicles runs the risk of the robots going awry.

The war in Iraq has proved a fertile testing ground for autonomous and unmanned vehicles of all kinds.

The 2005 report to Congress says their 2004 test involved a 142 mile route but no vehicle completed more than 7 miles. Yet with that paltry completion they call it a success. There were nearly 200 teams in the 2005 contest.

Their first challenge was a qualifying exam where the vehicles were sent through a 2.5 mile course laid out at an airfield. The 2.5-mile route included waypoints with associated speed limits and route width and was provided to teams in advance. Course features were representative of the GCE desert course: a narrow opening (cattle gate), a relatively steep uphill/downhill section, a vehicle-passing test, and a 100-foot tunnel that blocked GPS signals. Each team was offered three or more opportunities to run the course. Vehicles were evaluated on their ability to remain within course boundaries, avoid obstacles, and finish as quickly as possible.

The vehicles which qualified then were sent on a 132-mile route contained a series of graduated challenges beginning with a dry lake bed, narrow cattle guard gates, narrow roads, tight turns, highway and railroad underpasses. Travel surfaces included broken pavement, gravel utility roads, and off-road trails. The route featured more than 50 turns of at least 90 degrees, leaving only a slim margin of error for vehicle navigation systems. In many areas, vehicles that left the center of the route were quickly mired in soft sand or faced impassable conditions. Vehicles passed through tunnels and avoided more than 50 utility poles situated along the edge of the road. The route culminated with Beer Bottle Pass, which featured a steep, narrow downslope with a sheer drop-off on the side. Course speeds varied from 10 mph in sections deemed unsafe for higher speed, to 40 mph on the
dry lake bed. Completing the 132-mile route required approximately 6 hours at the defined course speeds. Each autonomous vehicle was monitored by DARPA via a real-time tracking system and was followed by DARPA personnel in a control vehicle equipped with an E-stop system.

The third competition of the DARPA Grand Challenge, known as the "Urban Challenge", took place on November 3, 2007 at the site of the now-closed George Air Force Base (currently used as Southern California Logistics Airport), in Victorville, California. The course involved a 96 km (60-mile) urban area course, to be completed in less than 6 hours. Rules included obeying all traffic regulations while negotiating with other traffic and obstacles and merging into traffic.



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