Patent Application
20070270285
In order for a treadmill surface to move in any direction, it must have two perpendicular vector motion components, plus and minus X, and plus and minus Y. A controlled combination of these motion vectors creates a sum vector that can create surface movement in any direction. The omni-directional treadmill (ODT) used a flattened toroid belt as the active surface, and uses motorized wheel assemblies to rotate the belt around the minor axis for X direction movement, and around the Y axis for Y direction movement. The motors may be controlled with a manual or computer operated speed controller.
The toroid belt must be fabricated from a material flexible enough to be folded in the desired shape, yet durable enough to walk or run on while resisting wear. The material should be non-porous so that it can contain internal lubricant. A rubber-like polymer about ¼″ thick would be an example of such a material.
A closed-loop motor control system 103 integrated with a sensing device may be added to automatically keep the user 106 centered on the treadmill 207. Many applications, such as “Virtual Reality” (VR) simulations, as well as all manner of Video Games, would benefit from such an arrangement.
A programmable motor control system 104 may be added to allow the pre-programming and repeated playback of various motion routines. This arrangement could be especially useful for applications in the film industry, where the same user movement may need to be accurately repeated over several takes.
The entire treadmill mechanism may be mounted to a motion platform 209 to allow various angular motions and positions of the treadmill. Tipping the surface with actuators 105 would be useful for simulating inclined terrain, such as the side of a hill. The Y-direction motor 102 is mounted to the motion platform 209 with a mounting bracket 108 and moves freely with the platform 209.
A useful application for an omni-directional treadmill (“ODT”) would be for use in “Bluescreen” (Chroma-Key) effects for the film industry. The Bluescreen technique involves shooting foreground action against an evenly-lit monochromatic background (usually blue or green) for the purpose of removing the background from the scene and replacing it with a different image or scene. Often, use of this technique is limited by the size of the monochromatic background, which is usually a single curtain or wall, and never larger than the size of a studio sound stage. If the action for a scene called for an actor to run or walk great distances against an alien landscape, for example, the action would normally be confined to the dimensions of the monochromatic background. If the actor were on an ODT that was the same color as the background, the action could take place while the actor remained in a relatively small area in front of the monochromatic background. The continuous surface of the toroid-belt ODT lends itself to smooth coloration that would be difficult to achieve with other ODT designs in which the surface is composed of many moving parts.
The belt 207 rests on the flat surface 203 on the motion platform 209. The platform has a concavity 308 that allows for the mounting of the X-direction rollers. The platform extension 307 leads to a flange 306 which can be mounted on a frame, actuators, or a surface.
If the X-direction motors 101 are moving, and the Y-direction motor 102 remains stationary, the X-direction roller wheel assemblies 302 will rotate, with the small rollers 303 stationary within the wheel bodies 304, while the Y-direction small rollers 204 will free-spin within their stationary wheel bodies 205, creating surface movement only in the X direction. Conversely, if the Y-direction motor 102 is moving, and the X-direction motors 101 remain stationary, the Y-direction roller wheel assemblies 208 will rotate while the X-direction small rollers 303 will free-spin within their stationary wheel bodies 304, creating surface movement only in the Y direction. Movement in any direction other than pure X or pure Y will involve a combination of both types of wheel assembly movements.
While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention.
