Intelligent Vehicle Source,
April 1999

Stereo Vision Leads Demo Alpha Vehicles Cross-Country

During the last week of September, “Demo Alpha” was the focus of US troops and Army decision-makers at Aberdeen Proving Ground in Maryland (USA). The field trials and VIP event showcased the capabilities of two autonomous scout vehicles developed under the US Army’s Demo III program. Demo Alpha was the first of three annual demonstrations planned under this program.
The vehicles successfully criss-crossed fields and woodland terrain at speeds of up to 20 mph, with the only human input being “waypoints” used to define a high-level path, much in the same way a military commander would instruct troops to survey an area of several square kilometers. Between waypoints, the vehicles successfully detected and avoided obstacles such as rocks, telephone poles, trees, logs, and roadside signs with no human intervention.

Begun in early 1998 under the leadership of the US Army Research Laboratory and prime contractor General Dynamics Robotic Systems (formerly Robotic Systems Technology), this $25M, three-year program represents the largest ongoing US government investment in automated vehicles. Major subcontractors are SAIC and Sarnoff Labs. Contracts for development of supporting technology with organizations such as the Jet Propulsion Laboratory, Carnegie Mellon University, and the National Institute of Standards and Technology (NIST), brings the total price tag of the program to approximately $50M. Demo III literature indicates that the program seeks to develop and demonstrate new and evolving autonomous vehicle technology, emphasizing perception, navigation, intelligent system architecture, and planning.

The program calls for the vehicles to perform a variety of military scout reconnaissance functions, with the autonomous mobility simply a supporting function. These mobility requirements call for the vehicle to maneuver autonomously while avoiding all non-negotiable obstacles, at speeds of up to 40 mph (64 kph) on primary roads and at 20 mph (32 kph) cross country. Per-vehicle costs in low volumes are on the order of $500,000.

The mature version of the vehicles, called the Experimental Unmanned Vehicle (XUV), will employ a wide variety of sensors for mobility. These include day/night stereo vision, a scanning laser rangefinder, and two radar systems, a 2 GHz radar to penetrate vegetation (under joint development with researchers in the UK) and a 77 GHz radar for imaging obstacles at longer ranges. Additional small ultrasonic sensors will also be employed for close-in safeguarding functions. The vehicle mechanics include four wheel drive and front/rear wheel steering.

Long Days in the Field

The weeks leading up to the demo were exceptionally intense, particularly because both the laser range-finder and the millimeter wave radars were delivered only a few weeks prior to the event. Stereo vision and GPS navigation had been integrated onto the vehicles earlier in the summer. Working almost continuously during late August and September, developers were able to make exceptional gains in stereo vision function, while at the same time battling reliability and software problems with the newly delivered equipment. Ultimately, stereo vision was chosen as the prime sensor for Demo Alpha, with full integration of the other sensors to continue after the event. As one result, the vehicles could not detect negative obstacles (e.g., holes, ditches).

Noting the surprisingly good performance of the stereo vision system, Army program manager Chuck Shoemaker called these capabilities a “breakthrough.” Robbie Mandelbaum of Sarnoff Labs agreed, saying that Demo Alpha “has really proven the robustness and capability of stereo vision.” Employing a swiveling camera head to expand the field of view, also referred to as “active gaze control,” this subsystem was based on contributions from researchers at NASA’s Jet Propulsion Laboratory.

Troops in Charge

Being sure to focus system development on the eventual user, the first four days of Demo Alpha were devoted to use of the vehicles by Army scout troops, as they experimented with use of the vehicles to support their standard mission operations. The final day was focused on Pentagon and Army VIPs who will ultimately make decisions about bringing such systems into full production. A key customer is the Army Training and Doctrine Command (TRADOC), who has the responsibility to define requirements for new support capabilities in military operations. A TRADOC requirement for such vehicles would be the “magic bullet” to propel these types of vehicles into full usage.

Demo Bravo A Year Away

The next major program demo is Demo Bravo, scheduled for October 2000 at Fort Knox, Kentucky, at which time additional sensors and road-following capability will be incorporated. The final program demo in summer of 2001 will incorporate four vehicles. At this time, according to program literature, “troops will be able to experiment with small, highly agile, unmanned vehicles … which will enable a meaningful assessment of the promise of autonomous robotic ground vehicles early in the next century.”

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