TWT News

Redesigning the Wheel: the Reconfigurable Wheel Track

Wheels are round. This is an established fact regarding carts, vehicles, and most modes of transportation. The wheels on the bus go round and round, we sing as children. So yes, a wheel is round. Except when it isn’t.

The Reconfigurable Wheel-Track.
The Reconfigurable Wheel-Track. Image credit: Carnegie Mellon

In a collaborative effort between Carnegie Mellon and the Defense Advanced Research Projects Agency (DARPA), the Reconfigurable Wheel Track was created. The RWT can transform a tire into a track while a vehicle is in motion. With just the push of a button and a few seconds, military vehicles are able to adjust to any terrain. In transforming into a track, the shape morphs from a circle to a triangle.

The RWT initiative itself is part of the Ground X-Vehicle Technologies program run by the Pentagon. Other goals of the program, according to DARPA’s website, include reducing vehicle size and weight and increasing vehicle speed in “today’s armored fighting vehicles.” The bullet point Carnegie Mellon tackled- “access 95 percent of terrain”- is of particular use for military vehicles used in desert or mountainous regions.

As for the Ground X-Vehicle Technologies program, there are four main categories for improvements and research. The RWT falls under the first area, “radically enhanced mobility.” From the DARPA website:

Gif showing RWT at work
Gif by CNET

“Ability to traverse diverse off-road terrain, including slopes and various elevations. Capabilities of interest include revolutionary wheel/track and suspension technologies that would enable greater terrain access and faster travel both on- and off-road compared to existing ground vehicles.”

Carnegie Mellon announced in November of last year that the RWT was one of the winners for Popular Science’s “Best of What’s New” Award. Dimi Apostolopoulos, a senior systems scientist at Carnegie Mellon University’s Robotics Institute said in a statement: “Creating a reconfigurable wheel-track system that works on a moving vehicle and at high speeds was an exceptional challenge, but our NREC team came up with a design that works and has the potential to transform ground mobility. We are appreciative of DARPA’s GXV-T program and we thank the editors of Popular Science for this recognition.”

On April 19, a video showcasing a test of the RWT was posted on YouTube (see below). While it only shows the system on pavement, it proves that the technology can work. No doubt additional tests, particularly on less smooth terrain, will be done before the RWT is implemented on active military vehicles. The last thing anybody wants is to have the wheel-to-track conversion fail in the middle of an active war zone.

While designed and primarily used for military functions, some commercial car companies are offering tracks for consumers. This is more geared towards drivers braving conditions like sand or snow but could theoretically be usefully to anybody. The GMC Sierra All Mountain concept from 2017 is the most extreme example, with tracks built in instead of the traditional wheels. It was designed for a partnership with Vail Resorts.

Other creations from the GXV-T program include technologies like the Multi-mode Extreme Travel Suspensions. Having a good suspension is critical when traversing abnormal terrain, and the METS gives the vehicle the ability to raise wheels 30 inches or drop 42 inches. Each wheel can be controlled separately as well. This, combined with the RWT, would make getting stuck almost an impossibility. They can all be browsed through on DARPA’s website.

Yes, the wheel is round, and the children’s song remains the same. But in the future, it may need a few edits to keep up with the times. The wheels on the bus go round and round… and can go off-road in an instant.

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