Hankook's crazy transforming wheels inspired by origami waterbombs
Hankook's R&D department has been working with biorobotics experts from Seoul National University and Harvard engineers on a weird transforming origami wheel project. These folding oddities can drastically alter their diameter and carry heavy loads.
It's taken nearly a decade to get to this point, but the team has got a fully functioning set of transforming wheels built and attached them to a couple of demonstration vehicles, demonstrating that the wheels can vary their diameter from 46 to 80 cm (18.1 to 31.5 in), while supporting enough weight to put a full-size vehicle on top.
The wheels are a three-layer construction based on a thick, flexible composite membrane designed to fold along similar lines to an origami waterbomb. To add structural strength and wear resistance, the non-folding panels are sandwiched with laser-cut aluminum facet panels, which hold most of the membrane rigid, with the exception of the fold lines.
Left to their own devices, the wheels collapse to their minimum diameter, but squeezing them horizontally causes the wheels to fold up to their maximum diameter, where internal locking plates add extra rigidity to the structure. So the team has fitted up both a lab demo platform and a Jeep Wrangler with a set of these wheels, as well as pressure plates that push outwards on the inner hub walls to vary the diameter of the wheels at will.
That's the how of it, but there remains the question of why. In video demonstrations, the team shows how they can be used to let small robots get nice and low to duck under obstacles, or high in order to travel faster and smoother. Previous prototypes have also included extending bars that fold out as the wheels expand, effectively putting a sort of climbing apparatus on the wheels that can pull a vehicle over ledges significantly higher than the wheel diameter.
The researchers point out that this flexible design has some give in it, suggesting that there's a suspension benefit too, but it's hard to see them being a ton of use on a road vehicle, even if the outer aluminum pates were covered with grippy rubber. The multi-faceted surface of the latest design is certainly much smoother-rolling than earlier prototypes, but it still looks like a lumpy, bumpy ol' ride compared to, say, a regular tire. The team says it doesn't expect these things to be commercially competitive; certainly not in their current form.
On the other hand, this kind of convertible capability could come in handy in certain extreme off-road environments, particularly off-world applications like rovers designed to explore other planets. At the least, it's certainly interesting to look at.
Check out a video below.