From DARPA to the battlefield: Oshkosh demonstrates driverless PLS vehicle; robot truck could carry beans and bullets in war zones with less risk to personnel

Diesel Progress North American Edition, May, 2006 by Bill Siuru

Virtually every modern war has introduced--or at least greatly hastened the development of--new mobility technology. In WWI, it was the tank, WWII, the airplane and Jeep and in Vietnam, it was the helicopter. For Afghanistan and Iraq, it could be the unmanned vehicle.

Already, unmanned air vehicles (UAV) like the Predator and Global Hawk, are performing high-risk missions without putting human pilots in harm's way. Now because of the risks to troops posed by suicide bombers or improvised explosive devices (IED), the push is on to develop unmanned trucks.

One in four military casualties in Iraq is part of a supply convoy. The best way to protect troops is to keep them out of trucks delivering food, supplies and ammunition in combat zones. Thus, Congress has mandated that by 2015, one-third of all military ground vehicles be unmanned.

In response, Oshkosh Truck Corp. recently demonstrated an unmanned version of its Palletized Load System (PLS) vehicle at the U.S. Army Tactical Wheeled Vehicle Component Technology Demonstration Center in Yuma, Ariz. According to Gary Schmiedel, Oshkosh's vice president for Advanced Product Engineering, "Following the success of TerraMax at the 2005 DARPA Grand Challenge, we knew the next step was to take this technology and integrate it into other vehicles used in situations suited for unmanned missions.

"Because of its heavy use in resupply missions, we selected the Oshkosh PLS, to be the second Oshkosh unmanned vehicle. An unmanned resupply vehicle would immediately meet a significant military need and increase the safety of our troops."

The 10-wheel-drive truck features the "unmanned navigational kit," an improved version of the systems used during the 2004 and 2005 DARPA Grand Challenge races (see December 2005, Diesel Progress). The system has undergone additional testing in desert environments, similar to those in the Middle East.

Like the TerraMax Medium Tactical Vehicle Replacement (MTVR) used in the Grand Challenge, the PLS version was developed by Oshkosh Truck, with assistance from Rockwell Collins and the University of Parma, Italy. Rockwell Collins developed the Vehicle Management System (VMS) and University of Parma provided the vehicle's stereo vision system.

Hardware was selected to withstand hot desert conditions and withstand off-road high- and low-frequency vibration. Dust is not a big problem because all the computers are housed in a closed container cooled by a closed-loop, filtered, air-conditioning system.

The VMS includes hardware and software for vehicle sensor management, navigation and control that interface with the vehicle's throttle, braking, steering and transmission as well as both navigation and perception sensors. The VMS emulates a human driver. A real-time path planner computes the course using the desired path while avoiding the obstacles along the way.

The behavior management module, the "brain" of the system, monitors and reacts to dynamically changing conditions. It receives input from the real-time path planner, obstacle database, navigation sensors and the vehicle interface module.

Both LIDAR (Light Detection And Ranging) and stereo vision is used for obstacle detection. There are two forward and one rear-facing SICK LIDARs, plus an Ibeo Automobile Sensors LIDAR mounted in the bumper. These state-of-the-art sensor systems plus a recovery maneuver allows backing of the vehicle over recently traversed terrain.

The exact location of obstacles is obtained via stereo triangulation between the two views of the object and further refined via sensor fusion with raw data from a laser scanner in the front bumper. In this way it is possible to detect thin vertical posts and fence poles. Two cameras mounted at a distance apart on top of the vehicle--like two eyeballs with overlapping vision--provide digital depth perception. This, plus GPS and navigation systems, provide a dependable, precise and high-resolution picture of the surroundings and location. If an obstacle is detected, the software determines whether to go over it, around it, and at what speed.

The PLS vehicle is totally autonomous once en route, but it is programmed by the mission. Much like any manned vehicle, the "driver" of the PLS must know the destination upon setting out in its mission. As a result, the navigation software has the capability to be programmed to only travel a set course. Navigation relies on Differential GPS (DGPS) provided by Trimble with corrections provided by Omnistar and WAAS (Wide Area Augmentation System) with dead reckoning used when GPS is not available, such as in a tunnel.

And how soon may the technology be fielded, "I think it's months, not years before this is ready for real-world use," said John Stoddart, president of Oshkosh Truck's Defense Division.

Oshkosh also sees other applications for the technology. For instance, it also is developing a driverless snowplow truck for use on airport runways.

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BILL SIURU, PHD, PE