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• Redirected walking with a VR shoe

  finallyfunctional • 03/13/2023 at 13:15 • 0 comments

  Recently in my discord we had a conversation about negating drift from the origin and supporting omnidirectional movement with a VR shoe that isn't actually capable of omnidirectional movement. Maybe it's limited to only be able to move forward and backward, and to turn or spin. If a VR shoe is capable of spinning the user or turning the user without them being aware of it, you could combine that with redirected walking to possible allow near-infinite walking in VR.

  Two ideas are a VR shoe capable of negating the user's forward and backward motion and able to turn or spin. Use it to negate the user's motion when they are walking forward or backwards, but if they start to drift a little, turn the user slightly, and or slow or increase the shoe speed, to start moving them back to their origin. Or have a VR shoe that is just capable of turning the user. As they walk forward or backwards, or side to side, just keep turning the user in circles to keep them in the play space. 

  Maybe you could do near-infinite walking in the VR game in a much smaller playspace than would be required for traditional redirected walking. And you could use them on carpet and other surfaces that would be harder for a shoe that actually moves you. I'd be worried about the user getting dizzy, and I'm sure there are other things to worry about, but maybe the pros would outweigh those cons.

• Omnidirectional Sphere Wheel

  finallyfunctional • 02/06/2023 at 00:18 • 0 comments

  I describe a 2in diameter omnidirectional wheel here.

• Motorized VR Shoe Concept

  finallyfunctional • 12/17/2022 at 13:46 • 0 comments

  I've made motorized VR shoes in the past.

  I was thinking about some of the challenges of motorizing VR shoes, especially if you want full omnidirectional movement. The three main issues I ran into where size constraints, weight, and weight distribution.

  Motors, batteries, electronics, the drive mechanism, and other components all add weight and take up space in the shoes. The weight and small size constraints are the hardest to deal with, especially if you want shoes for people with small feet. 

  For weight distribution, the user will shift their weight between the ball of the foot and heel as they walk. A while ago I built a pair of massive motorized omnidirectional shoes that used omniwheels. Some omniwheels were for forward/backward motion, some were for side to side. I found that I could distribute my weight onto the wrong set of wheels, so the other set had no traction. I go into more detail and show what this looks like in this video. Some sort of suspension system was needed. 

  I've had the idea for a while now that maybe to deal with the size constraints, some of the components don't have the be in the shoe itself. This isn't new, the University of Tsukuba shoes had the motors mounted in a backpack. But I was thinking that maybe they could be mounted on the back of the user's calf to avoid having to run something all the way up to the user's back. 

  So maybe have a frame similar to running stilts, part of which does rest on the back of the user's calf, and mount motors and electronics there to keep the shoe itself smaller. That would provide a lot more room to play with.
  

  That idea doesn't deal with the weight and distribution of weight problems. I was thinking what if the VR shoe itself is passive, and behind the VR shoe is a motorized caster connected to vertical rods that can slide up and down along the frame that is on the user's calf. 

  There would be a mechanism using springs that push the motorized caster into the ground, such that when the user lifts their foot, the springs push the shoe up and therefore the caster down, keeping the wheel in contact with the floor. To deal with the weight of the whole device, as the springs push the caster down, they also help the user lift their foot, negating the weight. 

  For distribution of weight, if the springs are strong enough and push into the ground hard enough, they should always have traction...theoretically. 

  The motorized caster could be something similar to what the Summerboard uses. Omniwheels could be used too, but a reason I don't really like them is they can't be used on a squishy, rubbery surface like I use in my current setup. That kind of surface reduces noise and increases traction. But omniwheels won't work on them because there isn't enough space between the rollers and the frame of the omniwheel itself.

  So in summary, have a frame that runs up the back of the user's calf and mounts to the shoe, similar to running stilts. It could have a pivot point around the ankle. Mount a spring loaded vertical rod to the frame on the calf. Have a motorized caster coupled to the vertical rod. The springs will negate the weight of the device and make sure the caster always has traction. The calf frame allows components to be mounted there, getting around space constraint.

• Video and Photos of Motorized Caster

  finallyfunctional • 04/22/2022 at 02:29 • 0 comments

  In a previous post I described an idea I had for a small, motorized caster. I took that design and made it. Here is a quick video showing my first build.

  Here's what it looks like next to the passive VR shoe. You can see it's slightly shorter.
  

  Here's what it looks like next to a regular shoe. I'm thinking I'll have one right under the heel as shown, two more right in front of it (so three under the heel forming a triangle), two more behind the ball of the foot, and two more in front of the ball of the foot.

• Motorized Caster

  finallyfunctional • 04/16/2022 at 13:12 • 0 comments

  I had an idea for a motorized caster yesterday and spent some time making a model of it. Up until now I haven't found a motorized caster or thought of one that I think would be small enough and powerful enough for a VR shoe. But this one might be.

  It's 1.375in tall and 1.5in wide, so small enough.

  The wheel on the bottom is tilted. It rolls on the side that is horizontal. The very top spur gear is used to turn the whole caster to set the direction. The lower spur gear is used to turn the upper bevel gear, which turns the slanted bevel gear, which turns the wheel. So lock the direction and turn the lower spur gear to move the caster in the locked direction.

  It uses a few needle roller thrust bearings, a 6mm bearing, and a 6mm bent screw.

  These are a few test pieces of the bevel gears.

  I'm thinking that 2-4 of these could be put on a VR shoe under the heel, with 2 more under the ball of the foot and 2 more under the toes. The casters could be coupled together by belts so that 1 or 2 powerful motors could be used to drive them, and 1 or 2 smaller motors could be used to rotate them. 

  I'd like to allow the VR shoe to bend at the ball of the foot. The issue is that the casters on both sides of the bend couldn't be coupled by belts. The belt would bend and get stretched when the user bends the VR shoe. A possible resolution to this would be to have two spherical gears, one on each side of the bend. The spherical gears could have groves in them to create teeth. When the VR shoe is bent, the gears will still be in contact, with one gear moving along the other and the teeth of one gear sliding in the grooves of the other.

• Three Joint Arm + VR Shoes Concept

  finallyfunctional • 10/17/2021 at 16:14 • 0 comments

  I made a quick sketch of this idea. These sketches are just meant to explain the general idea.

  The two rectangles are VR shoes, similar to what I have already made. A shoe is coupled in its center to a pair of arms as shown. The ends of the arms and center of the shoe are pivot points, joints. As the user walks the arms will pivot around the joints. There is also a circle in the middle with a pivot point in its center to support the user being able to turn and walk in any direction.

  The idea is to put either motors or springs on the joints so that when the user extends his foot the motor or spring will pull the shoe back to the center. I illustrate the idea here with some torsion springs.

  I imagined this being the default state of the arms, where they basically point backwards. However there may be a different default state that is better.

  The next sketch adds some circles. These are meant to represent casters.

  There are two casters at the front of each shoe and one on the arm, situated behind the shoe. I think with these casters and rigid joints the shoes will be stable.

  Finally, slits could also possibly be added to the arms to make them more dynamic and support more configurations. Linear actuators or compression/extension springs could be used to move the arms along the slits.

  My thoughts on this concept are - 

  • Simple design. Could be active with motors at the joints or passive with springs.
  • If springs are used the user will feel resistance when extending his foot away from the center, but it will help him bring his foot back. A balance for the resistance would be needed. Motors wouldn't have this issue.
  • When the user is extending his foot, he could theoretically backdrive the motors and recharge the battery.
  • The arms may get in the way or collide with each other when doing certain movements, like crossing feet.
  • It's possible to collide with the center circular piece while walking.
  • I'm not sure how well the center circular piece will turn with the user.

• Passive VR Shoe with Rack and Pinion Mechanism

  finallyfunctional • 10/17/2021 at 15:52 • 0 comments

  Here is my explanation of the idea.

  https://i.imgur.com/Kwwp7m4.mp4

  A rack and pinion mechanism is what I use in the video, but a lever mechanism could be used as well. The main issue I have is being able to fit enough gearing to convert the small amount of vertical distance to the large amount of horizontal distance required.

  The gearing has to be set up correctly so that there isn't too much input torque needed to overcome the gearing. For example, I weigh 165 pounds and if you're using a 1 inch pinion then I will get a torque of around 9 Nm. The input torque required for the gearing ratio cannot be higher than that. With those restraints I believe that using a large wheel on the output is best, since it reduces the gearing needed.

  I am currently working on my other VR shoe project but want to eventually try to make a working version of this concept. If I can, this VR shoe could be very cheap to produce.

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