Liddiard Omnidirectional Wheels

Omnidirectional wheels are one of the hardy perennials of the world of invention. There seems to be something about the prospect of effortless parallel parking that sets the creative juices of backyard inventors flowing, and the result over the years have been a succession of impressively engineered ways to move a car sideways.

The latest one to come our way is courtesy of Canadian inventor [William Liddiard], and it is worthy of a second look because it does not come with some of the mechanical complexity associated with other omnidirectional wheel designs. [Liddiard]’s design uses a one-piece tyre in the form of a flexible torus with a set of rollers inside it which sits on a wheel fitted with a set of motorised rollers around its circumference. The entire tyre can be rotated round its toroidal axis, resulting in a tread which can move sideways with respect to the wheel.

The entire process is demonstrated in a video which is shown below the break, and the small Toyota used as a demonstration vehicle  can move sideways and spin with ease. We would be wary of using these wheels on a road car until they can be demonstrated to match a traditional tyre in terms of sideways stability when they are not in their omnidirectional mode, but we can instantly see that they would be a significant help to operators of industrial machines such as forklifts in confined spaces.

Omniwheels are a regular subject here at Hackaday, we’ve had quite a few projects feature them over the years. Most seem to use a variant of a Mechanum wheel, and a lot of them use a tricycle form factor. We’ve also had one or two rather nice builds of the wheels themselves.

Via [Itay Ramot] and [Patent Yogi].

46 thoughts on “Liddiard Omnidirectional Wheels

  1. While these are certainly clever and I’m sure will have some applications, their use on automobiles are unlikely. I just can’t see these permitting a turn at highway speeds without the risk of excessive side-slip.

    1. At the moment it doesn’t appear to be capable of more than an a few inches per second. The videos where he gets in the car and “drives” it around is enormously sped up, if you watch closely.

      1. … and good luck braking.

        And let’s not even talk about durability with the rubber subject to such stresses or the tire footprint.

        Certainly, if you look at the trees and in particular the flapping flag at the top left seems that the video is speedup by at least 8x without any indication to the viewer. Video that claims made by a proffesional patent company. That is definitely intentionally misleading.

  2. Sorry, my BS indicator goes off here.
    You probably can never balance such a wheel, so it will only be usable for very slow speeds.
    The tire has no strong connection to the rim. So breaking probably will not work.

      1. Not only that, tires nowadays have gone through a lot of research, from rubber hardness and strength, to deformation due to centrifugal and traction forces. It’s a very complicated matter and that’s why you still don’t see other types of tires being widely used out there (like the airless tires).

        The tires in this article will certainly find it’s way to some specialized applications, but even there, they are very complex and probably not cost effective compared to traditional omni wheels.

      2. I see them fly off and the braking will be done by the rim as your rubber wheel goes on its own journey.
        Makes braking so much more exciting though. And it’s cheaper to get new tires because the side of the road will have tons of them!

      1. What would really be a concern is whether the torus would stay on the rim in the event of a high-speed violent swerve, say to avoid something on the highway.
        That aside, any small pieces of gravel could well be picked up when operating the tire in sideways mode and be taken inside the rim where it could jam the mechanism.
        Modern tires are deceptively simple devices with a ton of engineering and over a hundred years of refinements in them, the fewer the number of parts (moving or otherwise) the fewer things there are to go wrong or fail when you might need them most.

      1. On another note: I call BS on “it does not come with some of the mechanical complexity associated with other omnidirectional wheel designs”. The thing comes with multiple additional rollers and even motors. I would not consider that less complex. What happens when one of the motors breaks?
        To me, Mechanum wheels seem like a much more elegant solution to the problem.

      2. I don’t think they’re meant to be inflated. If they were, the rubber tire and the central torus inside it would no longer make contact.

        Cool demo, just a little misleading. I don’t think these wheels are intended to be used on normal vehicles at all. One was used in the demo only because it was readily available. Special-purpose military and science vehicles are where these wheels may find use.

        1. They way I understood it, the inner torus is just another set of rollers that in a way pulls the tire towards the other rollers and the motors to give them more traction. It doesn’t have to touch the tire on all sides.
          Also, if the tire touched the inner torus on all sides, and wasn’t inflated, it would be a very bumpy ride. Almost as though you were driving on the inner torus.

        2. In it’s current state I can’t see it holding up to the harsh environments that would be demanded of it in a military capacity.

          Might be good for moving goods around a warehouse or factory if they can speed the system up a bit.

      3. Well spotted.
        But I suppose you could make a valve that extend inwards, but then you need to rotate the wheel in various ways for 10 minutes to find it, and then get the plug out (you can’t leave it open to pick up dirt).

        All in all I don’t see the guy make all that many millions.

  3. While definitely an impressive* proof of concept…… I can’t see this on the road in any common capacity. Take away the “Wow, it’s on a car” factor and you are left with something that while still impressive is most likely going to find it’s niche in some highly specialized application.

    *In that it is moving a relatively large object.

    1. remote controled multi wheeled trailers for moving hundreds of tons like transformers and large turbines springs to mind. as the motive force is in the wheel couiod reduce the complexity of that sort of machine.

  4. Where do you put the steel belt? These tires go through a heck of a lot of stretching between the inner diameter and outer, so they cannot be reinforced. What’s the contact patch? Sidewall stiffness? Now that the wheel is so heavy, how responsive is the suspension?

    It’s cute, but the materials science needed to perform at least as well as a 1916 tire isn’t there.

  5. I’m surprised that the rubber allows for this form of sideways rotation. The stresses on the rubber are quite different then they are on conventional tires. How do you make a rubber tire like this, that interesting. Because every side of the tire will eventually be on the outside, there the rubber stretches the most. On the inside the ribber is compressed the most. In order to evenly distribute the forces on the rubber you must have a mold that corrects for that. Otherwise if the tires is rotated 180deg (the inside is out) the rubber is stretched max. and would be thinner and therefore more vulnerable.

    I also wonder how the electric motors in the rim are powered, do they use some form of dragging contacts?
    There is a lot more to this concept then you would imagine at first and honestly I can’t see it being an improvement (regarding simplicity) over mechanum wheels.

    Nonetheless… a cool concept.

    1. That’s an excellent point and not immediately obvious, at least to me. They would need to manufacturer it as a straight cylinder and wrap it into that shape, and use vulcanization to bond the ends.

  6. More “Solar freaking roadways”….
    1. How do you power and control the motors in the wheel? For the demo you could probably package some batteries in there and control it with some variation of wireless. Not a practical solution in most use cases.
    2. How do you build the rubber tire? Tire fab today has an inner and outer mold. Hollow torus=no inner mold.
    3. How do you get the hard parts correctly placed inside a hollow torus with no openings?
    4. Twisting the torus in that axis is _hard_. There is a significant difference in circumference between the inside and outside of the torus. Twisting in this axis requires the rubber to stretch/compress to accommodate that difference as it twists.Minimizing this would require thinner walls and softer rubber which is against most of the other requirements.
    5. Wear. How well does this work when the tire has half the tread worn off? If you drive straight more than sideways (most likely) the tire will develop circumferential wear patterns, how will that effect the sideways motion?
    6. Dirt. Way too many delicate little gizmos too close to the road. Demo on clean concrete – sure. What happens when you run that through some mud a few times?

    Interesting idea? yep. Cool demo? check. Practical device? Not a chance.

    1. If I was to guess I’d assume that the set of visible lug nuts probably holds the two halves of the wheel together and somewhere underneath those are another set of lug nuts that actually hold the wheel to the axle. So you would probably just take those off, half of the housing would come off and the central rubber section of the wheel would be easily accessible. As would the secondary lug nuts to remove the whole unit from the axle.

    2. You change entire wheel, whole assembly with motors and batteries. Tire change for $499. Of course you would have to rename it to iTire and advertise it as “the tire of the future” or else no one would give you such money for that crap.

  7. I think this mechanism would be best in tubular movement – like an oil pipeline pig, except this maintains static friction instead of a pig’s sliding friction.

    One one each end of a platform and it could worm its way down a pipe of a similar diameter or larger.

  8. Why does the video need to masked the license plate? Seriously, they put up 4 highly customized wheels and all the power and electronics to make it work yet they could not bother to remove a license plate? So what if people found out about the license plate? It looks like a sub-$5000 car anyway.

  9. Loved the music.

    “Most likely, William Liddiard will earns millions from his patented technology.” [sic]

    Most likely, William Liddiard will loose his moneys, his family’s moneys and his friend’s moneys from this patented technology.

    We really need a patent system overhaul. The clerk obviously did zero research and the patent lawyers now have his relative’s money.

  10. I can see a use for this kind of wheel for moving moderately sized object to heavy objects in tight confines. With that said its probably cheaper to make a 6 wheel drive mover with independent steering to accomplish the same with probably less moving parts. The other thing is that those wheels have tires on them that for all intense and purpose have the contact patch of a bike, not good for something moving at a high rate of speed that weighs in at a couple of tons. There is a reason why even hybrids with hypermiling tires have a contact patch that is around 200mm, not 20mm as seen here.

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