Autonomous ground vehicle” doesn't always conjure up pleasant visions, especially if you think about the murder and mayhem caused by driverless big rigs in Stephen King's short story “Trucks,” or the robot tanks bent on destroying humanity in “The Terminator.”
But Gary Schmiedel, vp of engineering for Oshkosh Truck Corp., hopes to create a far more positive association for that phrase. “What's driving development of what we call autonomous, or driverless, vehicles is the desire to keep human beings out of harm's way,” he says. “This is particularly true in military applications. If we can keep a soldier out of a truck cab in hostile territory, we just might save their life,” he explains. “But it also applies to many commercial areas…where robot truck technology can help redistribute driver labor more efficiently and safely.”
Many of the robot trucks being tested in the field today are based on the cargo-carrying behemoths pounding out the miles for the U.S. Army and Marines in Iraq and Afghanistan.
The TerraMax, for example, is built on the Oshkosh Medium Tactical Vehicle Replacement (MTVR) truck platform originally designed for the Marine Corps. Built to drive 70% of the time in off-road conditions, the MTVR has an AWD TAK-4 independent suspension and central tire inflation that make rocks, dips, holes and crevasses easier to handle. The vehicle is also built to navigate 60% grades and 30% side slopes.
Oshkosh is currently getting the second-generation TerraMax ready for this fall's Grand Challenge, a 175-mile off-road race designed by the Defense Dept. to test robot trucks. Schmiedel points out that self-navigating vehicles bring there own set of challenges. “First, you must have a suite of sensor devices that know where the vehicle is, where it wants to go, and that can see obstacles ahead of the vehicle with a high degree of resolution.”
Second, a computer “brain” guided by a GPS satellite interface must gather that information and be able to direct the vehicle along a predetermined path, while also being flexible enough to change that path in case obstacles or other problems crop up.
“We're talking about making decisions in real time, and that's a lot harder than it sounds,” Schmiedel says. “Just watch yourself as you drive down the highway at 60 mph and see how many minor adjustments you make in a 15 minute span, [including] speeding up, slowing down or changing lanes, and you'll begin to realize just how much information you have to process at high speed to operate that vehicle safely and successfully.”
Finally, a whole series of what Schmiedel terms “low level controls” must be rugged and responsive enough for the computer to steer, stop, accelerate and shift gears without fail.
Drive-by-wire technology plays a big role in driverless vehicles by enabling onboard computers to do several things. First, it controls the steering via a “servomotor.” Second, it operates the accelerator and transmission via direct electronic interface. Third, the Bendix braking system uses EBS in conjunction with an actuator to operate the brake pedal.
Based on sensor data alone, the TerraMax must make its own decisions on route planning, obstacle avoidance and speed — without the aid of human intervention during the race, Schmiedel adds.
As far as commercial applications for the TerraMax, Schmiedel suggests snow removal on airport runways as one example. “This is a really good application for a vehicle like this because you have a fixed area that it will travel; you know where the pavement is and isn't,” he says. Using a robot truck is one way to get rid of the operator error that can occur when visibility is low and multiple pieces of equipment are being operated at the same time.
In this example, the robot truck isn't eliminating drivers altogether. Rather, it is freeing them up for other driving tasks. “These trucks can clear the runways all day and night, whereas a human operator needs rest and sleep,” Schmiedel says. “It's far more important to dedicate the human driver's time to clearing areas around jet ways and ramps, where lots of maneuvering takes place, rather than the routine back and forth clearing of runways. It's simply a more efficient and effective use of a driver's time and skills.”