Remote-operated excavator to unearth Navy explosives

With its operator sitting 1000 yards away, an excavator will soon begin digging up unexploded ordnance at a Virginia military base.

The Navy, Case Construction Equipment and students at Virginia Tech have created the remote-controlled CX160 excavator. Sitting inside a shielded trailer, operators will watch their work through video monitors linked to cameras on the machine.

Explosives were buried at the Naval Surface Warfare Center in Dahlgren, Va., between 1918 – when the based opened – and the mid-1950s.

“Munitions were buried in a number of sites around the base,” said George Clotfelter, the Navy’s lead engineer on development of the excavator. “The remotely operated machine will allow us to safely excavate the site.”

One graduate and five undergraduate students at Virginia Tech modified a software program called LabVIEW so the excavator could be operated from a safe distance. Senior undergraduate engineering students at the college are required to complete a class in which they create a product.

At a demonstration of the excavator’s special capabilities, an operator manipulated the machine’s joystick controls via the Internet from more than 1,000 miles away.

Addressing safety concerns about operating a 110-horsepower, 35,000-pound excavator from a remote location was a major focus of the class. To solve the problem, students created an emergency shutdown system using a line-of-sight radio link to the excavator that is separate from all other controls. If a continuous tone broadcast to a receiver on the machine is interrupted, the excavator will automatically shut down.

Three video cameras allow the operator to monitor his work, and more could be added if necessary, said Chris Terwelp, one of the students who worked on the project.

“The issue was how to make sure this thing doesn’t get away from us,” said Al Wicks, a Virginia Tech professor of mechanical engineering who supervised the students.

Case design engineers and their counterparts at Sumitomo Construction Machinery developed software to report fuel level, water and oil temperature – information an operator would normally see on a display in the cab. The software sends the readings in real time from the machine’s standard, onboard computer to the Internet, where it can be monitored through any PC with a Web browser or LabVIEW.

Once explosive material is unearthed, a Navy explosives ordnance disposal team will examine it – through X-ray, visual inspection or other means – and decide how to dispose of it. The team cold trigger a detonation at the dig site, the Navy’s Clotfelter said.

Dahlgren was named in honor of Rear Admiral John Adolphus Dahlgren, considered the father of modern naval ordnance. The 4,300-acre facility established as the Naval Proving Grounds has become one of the Navy’s largest research and development centers.