Arlington, Virginia - The US military’s Defense Advanced Research Projects Agency program first got onto our radar back in 2012 with its Grand Challenge for autonomous vehicles, but it also has a research project for manned vehicles, the Ground X-Vehicle Technologies program, that is quite literally re-inventing the wheel.
Tank designer J Walter Christie proved back in 1928 that, while taking the tracks off a tank made it a way more efficient road vehicle, tracked suspension was essential for military operations off-road. Since removing or replacing the tracks was a workshop job, that’s as far as the idea went - until now.
Developed in conjunction with Carnegie Mellon University’s National Robotics Engineering Centre, the reconfigurable wheel-track has six roller-brackets rollers, mounted around around a three-pointed rim, with an extremely low-profile solid rubber tyre. In normal road use, everything stays locked up and the wheel runs on its hub a usual.
On rough ground, however, the brakes are locked and the rollers unlocked so that the tyre revolves on the rim; then the hinged brackets are retracted to create a three-sided suspension set-up similar to that of a snowmobile and hey presto! You have a tracked vehicle. The whole process takes just two seconds and can be done without even slowing down.
And if you think it sounds like something out of a Transformers movie, watch the video.
Christie M1928 prototype tank demontrated that wheels are better for roads, tracks for cross-country work.
Also in the video and almost as spectacular, is a development of Christie’s Helicoil suspension, designed by Pratt & Miller, that offers insanely long travel - up to two metres of it! More than that, it’s independently adjustable - something Christie didn’t have the electronics to accomplish in the 1930s - so that the body of the little test buggy stays just about level even on a radical cross-slope that would have even a Unimog rolling over.
Less visual but just as impressive technically, is an electric in-hub motor developed in conjunction with British com[any QinetiQ, which manages to fit a 100kW electric motor, a three-speed planetary gearbox and a liquid-cooling system inside a standard 20 inch hub (all US Military vehicles use the same 20 inch all-terrain tyres).
Camo-clad supernerd Major Amber Walker explains that these are all part of a program to make soldiers more mobile by “avoiding armour and developing options to move quickly and be agile over all terrain”. Just imagine being able to buy reconfigurable wheel-tracks for your Jeep or Land Cruiser…