Automotive

Hankook's crazy transforming wheels inspired by origami waterbombs

Hankook's crazy transforming w...
Squeezing the sides of the hub together can nearly double the rolling diameter of this origami-inspired wheel
Squeezing the sides of the hub together can nearly double the rolling diameter of this origami-inspired wheel
View 3 Images
Squeezing the sides of the hub together can nearly double the rolling diameter of this origami-inspired wheel
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Squeezing the sides of the hub together can nearly double the rolling diameter of this origami-inspired wheel
A hydraulic system actuates the wheel transformation on this single-person demonstration vehicle
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A hydraulic system actuates the wheel transformation on this single-person demonstration vehicle
An internal locking skeleton adds rigidity at max diameter
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An internal locking skeleton adds rigidity at max diameter
View gallery - 3 images

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.

An internal locking skeleton adds rigidity at max diameter
An internal locking skeleton adds rigidity at max diameter

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.

A hydraulic system actuates the wheel transformation on this single-person demonstration vehicle
A hydraulic system actuates the wheel transformation on this single-person demonstration vehicle

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.

High-load capacity origami transformable wheel

Source: Science Robotics via Interesting Engineering

View gallery - 3 images
15 comments
15 comments
Adrian Akau
I am sure that there will be good use of this concept in the future. I have often thought about designing a car that could change its body shape just a tad according to its speed to reduce air resistance.
ppeter
Another great solution in desperate need for a problem it could solve?
CraigAllenCorson
This product will go NOWHERE in the passenger vehicle market. It's fine for robots, but that ride is WAY too bumpy for human beings.
1stClassOPP
I love it! Imagine the ratio difference in torque and speed, and obstacle clearance. Think variable ratio transmission. Great!
ARF!
I'm no mathstrologist. I'll just keep wondering if wide tires cancel out ground-hugging aerodynamitry.
AngryPenguin
Looks like it would be useful as a 'folding' wheel.
SpieroFantasio
Probably it is made to replace the gearbox similiar to a CVT.
knelipot
Mud boggers are gonna love these. When the mud pit gets rutted with tall, narrow tracks, just widen the tires and straddle the ruts.
Justin Clark
It's funny that it took researchers and scientists to come up with this idea that is just like a toy I had called the flex from the 1980s did the same thing thank you scientists
Worzel
The weak point is the 'hinge' and that is in exactly the position that will receive the most wear and tear in off road use. When the hinges start to break....!
I've a mini-digger, that has rubber tracks, and the failure point of those, is the steel cross pins that the drive wheel engages, which get ripped out of the rubber. So the weak point is the bonding into the rubber. These wheels will probably have similar fail problems.
If I can see these problems, then potential buyers will also, and will want some very convincing answers.
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