Low Budget Omnidirectional Treadmill

Omni-treadmill

Moving around in space is one of the major hurdles in virtual reality. A holodeck wouldn’t be much fun if you kept walking into walls.  [Gamnaught] is working on a simple solution to this complex problem with his budget omnidirectional treadmill. Omnidirectional treadmills have been around in various forms for a number of years. The idea behind them simple: allow a person walk in any direction without actually changing their position. This is a bit different from the unidirectional treadmill models found at the local gym. Some very complex solutions have been used to create omnidirectional treadmills, including multiple motors and computer control systems as can be found in the US Army omnidirectional treadmill.  [Gamnaught] kept it simple. He built a circular 2×4 platform 13-15 degree bowl. The bowl is covered with carpet, and the user wears furniture sliders on their shoes. The low friction of the sliders allows the user to walk, run, and even walk backwards on the platform. Bungie cords provide resistance so the user doesn’t walk off the platform.

The early results look promising. [Gamnaught] says the balance felt a bit weird at times and took some getting used to. Anyone who has spent time with the Oculus Rift or other VR systems will tell you – many aspects of virtual reality take some getting used to. The treadmill is still open loop, however [Gamnaught] hopes to add motion tracking with a Sixense STEM system. We think a OpenCV based system would work as well. We’ve also seen carpet sliders sold as a children’s toy to be strapped over regular sneakers. Going the toy route would avoid needing a dedicated pair of footwear for the treadmill. More build information can be found on [Gamnaught’s] Reddit thread on the topic.

34 thoughts on “Low Budget Omnidirectional Treadmill

  1. Very nice. I would be skeptical about an OpenCV system that would work in real-time to provide usable control, but I think latency is going to be an issue no matter what. Excellent build though, and I hope to see more from this project.

      1. That’s very fast, but 120 fps is still > 8ms delay. That’s not much in the grand scheme of things, but it does compound with display lag. Not to mention, getting 120 fps requires the right equipment. Most affordable CCD/CMOS cameras are 60 fps at best.

    1. Omni went “Commercial customers only” and “licenses only, no sales” (such B.S.), they go to the community for help starting up and then shut down to the community shortly thereafter.

  2. We did this in the 80’s wearing curling slipons’, and a belt with rubber straps, when you got tired you just kinda hung there. A few months later we got a big metal hamster ball type deal… there were injuries… good times!

  3. I really don’t think these things will take off. Whenever I see a demo vid of the Omni or the Virtualizer I just can’t get over how unnatural and uncomfortable it looks. The guys that demo it have practised for a long time to make it look natural but… I dunno, I’m not convinced. I think we need to get motors involved somehow. But doing that cost effectively… yeah, that’ll take some doing.

  4. I wonder if the individual facets cause any problems?

    If I were going to make such a “bowl omin-treadmill” – I think I would take a cue from how you make a parabolic solar cooker mold – just use a spherical cross-section rather than a parabolic one.

    You basically take a piece of pipe and pound it vertically (using a level) into the ground to act as an axle for a scraper “bar” (made from plywood or metal) with a cut-out shaped to the half cross-section of your form. You pile dirt around the pipe, and rotate the scraper around it, spray water, pat it down – keep doing this until you have your shape, then you can add a sprinkling of cement powder, more water, more scraping, let dry.

    Once you have a great enough thickness, you can then smear on some grease or other mold release agent, and lay down strips of fiberglass matting (or other cloth if you don’t need the glass strength), and epoxy. Keep building this up, layer by layer until you get the thickness needed or desired. Let it cure, then remove it from the mold.

    The inner surface may need a bit of sanding (and cleanup of the mold release agent), but once done, you have a nice smooth surface, no facets, which you can add your carpet, etc. Definitely more work to do that the mentioned system, but the result might be more pleasing to use.

    1. Hardest part would be to carpet without any wrinkles.

      The facets are there to relieve the stress on the carpet and keep it from concentrating near the bottom/stretching near the top.

      Unless you can mold the carpet with automotive felt?

  5. FWIW I’d rather float or fly around a virtual world. If I have to walk, let a joystick do it. I’m not gonna move into a computer-generated universe to *increase* the amount of exercise I get.

    I remember an early system used hand gestures, different finger-pointing combos, in a smart glove, to control one’s flight around the place. Depending on the architecture, sounds fine to me. I’d want a more weightless, 3D, space-based space than the 2.5D room-based spaces we tend to have in this apparent universe. It’d be better to spend time flying from one area to another in free space, rather than walking round a floor. You don’t need floors or walls or ceilings if there’s no weather to keep out, so why have them?

  6. I laughed at the bungee cord “safety” measure, it needs something like this medical research equipment has http://resourcesonbalance.com/neurocom/products/CRS.aspx Because of my brain injury I was part of a balance study. I’m one test the platform remains still but the cubical moves, it’s insane. I was OK until it looked like the front wall was about to fly over my head. I’m over 6′ tall, I grabbed the rail the harness attaches to before the harness had a chance to catch me.

    1. I dont think the bunjees are there for safety. They provide a slight restoring force that will make sure the user is always lightly pushed towards the centre. Otherwise you would just walk off the sides. Carpet sliders still provide some friction, so I imagine without the bunjees it would be more like walking on ice or any other slippery surface, more difficult, but not impossible to move.

  7. if one had sufficient space and funding: giant sphere floating in a giant bowl of water, submerged at least halfway, preferably much more, could be the platform for walking, and movement could be tracked using a mouse-derived method. safety nets/foam padding on the ‘horizon’ (stationary, not making physical contact with the sphere) would protect the subject from falling in due to imbalance , speed+ sudden stops, etc. and maybe even a smaller sphere making contact with the submerged base of the sphere to add resistance, or balance correction (360° rotatable wheel in contact with sphere to transfer rotational force in necessary direction) maybe even several wheels/spheres /’bearongs’ distributed around the sphere-platform.. but first, how do you make a giant ball that you can walk on?

    1. there are lots of ideas on how to track the movement, but i think the simplest answer has been left out – til now! (I think this is the simplest…) put rings under the carpet that sense the pressure of the feet sliding on it, or use them to track something embedded in the shoe slider. these would provide velocity and direction with the only latency being the microprocessor that reads and transmits the data to the main system.

      1. You could probably do surprisingly good things with 4 weighing scales. Use strain gauges, one on each corner, to measure the weight distribution. A bit of maths and you can work wonders.

        Still I think actual foot-based walking is a poor way of navigating a world though. If you’re gonna have a floor at all, people are gonna want to crouch on it, etc. As far as simply walking goes, who needs that? Whoever asked for a game where they have to walk around everywhere? Real life has that and it’s totally boring enough that we invented cars, and tamed horses first chance we got.

  8. There are other ways too. Take 2 simple existing treadmils. Replace the belts with wire ladders, one for X inside the other for Y, effectively crossing each other. Now stick some soft rubber studs on your shoes.

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