An unnamed stealth operation: self-mobile trailer provides autonomous operation using hybrid technology; allows for silent operation in military danger zones

Diesel Progress North American Edition, March, 2008 by Dawn M. Geske

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Following 24 months of development, Alion Science and Technology, McLean, Va., has demonstrated an autonomous robotic vehicle that has the capability to carry 1000 lb. of cargo. Not only is the self-mobile trailer (SMT) completely autonomous but it uses a diesel-electric hybrid, which gives it stealth capabilities when entering a danger zone.

"This vehicle features a very innovative design," said Rod Riddick, Alion senior vice president and manager of the Integration Solutions Group. "The vehicle is capable of nearly silent operation with extremely low visible, thermal, acoustic and radar signatures. It is highly mobile, capable of autonomously trailing a foot patrol over challenging terrain and fording small rivers."

Working under an $850,000 U.S. Army Small Business Innovative Research contract to develop a proof-of-concept vehicle that could support different missions for a small combat team, Alion's goal was to demonstrate an unmanned vehicle that could be used to transport high-density cargo on man-passable terrain and sustain operations in severe locations.

Ideally, the SMT is designed for a variety of military operations requiring silent entry into a combat area and will remove the danger of having a human present. Alion suggested applications such as expediting the recovery of parachuted payload bundles deployed with troops, acting as a lookout on a reconnaissance mission, assisting combat controller missions by providing laser ranging, surveying and targeting destination capabilities, or providing expeditionary power to support an operation.

Alion performs a variety of R&D and engineering projects for the Department of Defense, civilian government agencies and commercial customers. For the SMT project, Alion worked in cooperation with subcontractor General Dynamics Robotics Systems, a tactical autonomous robotics and command and control technology provider located in Westminster, Md.

The proof-of-concept SMT was built on a modified Yamaha Grizzly ATV 4x4 chassis and equipped with a two-cylinder Yanmar 2V78 diesel engine rated 22 hp. The hybrid operation of the vehicle is driven by an eCycle MG2-13 electric motor, which stores energy in four 12V Odyssey PC1200 batteries connected in parallel.

When operating in hybrid mode, Alion said the SMT is virtually silent and able to operate on the battery power for 60 to 90 minutes at 5 mph, allowing it to enter danger zones unnoticed. The electric motor can also be used to boost power to the 22 hp engine when additional horsepower is needed, Alion said, and supply an auxiliary winch equipped on the SMT to accommodate a variety of hoisting applications required of the vehicle.

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Electrical output is also generated to power an auxiliary panel at the front of the vehicle that supports electronic systems from recharging battery packs, powering communications, sensors, life support, telemetry, off-board lighting or public address systems. Outputs are 110 and 220 Vac, and 24 and 48 Vdc with variable zero to 12 Vdc.

Because the four-wheel drive vehicle's engine is only run as needed, a built-in 7 gal. fuel tank is all that is necessary to feed the engine. The SMT has the ability to use a fast-attach racing system to add more fuel bladders for extra-long missions where the engine will be running more, Alion said.

To make the SMT autonomous, Alion added GPS for navigation and a laser radar (LADAR) for obstacle avoidance. Three modes of autonomous operation allow the SMT to navigate a mission. In Follower mode, maximum speed and follow-through distance are set using the Operator Control Unit (OCU). The operator can then walk the path and transmit GPS waypoints back to the SMT while the vehicle navigates those waypoints following at a close distance. In Autonomous Waypoint mode, the operator uses a touchscreen on the OCU interface to place waypoints on a map, which the SMT is tasked to follow. In Tele-operation mode, the OCU and an on-screen navigation pad are used by the operator as well as a look-through video camera to tele-operate the vehicle. This is a 100% attention-demanding task, Alion said, that would typically only be used for a short period of time.

Besides the SMT's ability to maneuver on its own, it is also quite nimble--with the capability to ford water 36 to 48 in. deep. It has a maximum speed of 28 mph and can be transformed to hold Medevac stretchers, allowing injured personnel to be removed from a site. The top-mounted rack system provides a rail around the vehicle to transport cargo and reconfigures into two man-sized stretchers. When unloaded, the SMT weighs in at 1000 lb. or less and has dimensions of 53 in. wide by 96 in. long by 54 in. high, which allow it to be transported on HMMVV, CV-22, MH-47, MH-53, MH-60 and MARK-V military vehicles.

"I consider the SMT concept demonstration to be a huge success, as it provided a means to evaluate the performance and operational utility of the SMT prototype vehicle," said Sal Strano, product director with the Army's Program Executive Office for Simulation, Training and Instrumentation (PEO STRI) headquartered in Orlando, Fla. "Based on the results of the demo, I feel that the SMT proved that it could enhance a military operator's ability to carry a combat load, improve endurance in the field and increase situational awareness."