Omnidirectional Treadmill

Abstract

An omnidirectional treadmill for facilitating the VR experience includes a concave platform with a regular array of openings in which ball-bearing elements are installed, spanning the platform's upper surface. The platform is supported by a frame connected to a freely rotating body support to hold the user in position above the platform's central point. The combined use of the concave, ball-bearing-covered platform and the body support allows the user to move freely in a manner that allows the user's feet to roll on the platform floor, giving the user a feeling of considerable freedom. The user's movement is tracked and translated into movement in the VR application.

Description

[Technical Field]

[0001] This application is a continuation of, and the applicant claims priority from, International Application PCT / DE 2023 / 000137, filed October 11, 2023, under 35 U.S.C. §120. International Application PCT / DE 2023 / 000137 claims priority from U.S. Provisional Application No. 63 / 437,790, filed January 9, 2023, under 35 U.S.C. §119(e), the disclosures of each of which are incorporated herein by reference. International applications under PCT Article 21(2) have not been published in English.

[0002] The present invention relates to an omnidirectional treadmill device, and more particularly to an omnidirectional treadmill configured to provide the most seamless 360° movement to the user to support a VR experience. [Background technology]

[0003] The development of virtual reality (VR) technology has accelerated significantly in recent years, resulting in VR headsets such as the Oculus Quest now being very popular, as well as a thriving community of VR enthusiasts looking to enhance their VR experience with a variety of accessories.

[0004] Despite rapid developments in technology, obstacles still exist that prevent VR from becoming truly immersive and dominating the console market. For example, while initially putting on a VR headset is an engaging experience for many users, this experience is often quickly diminished when the user suffers from "motion sickness." Motion sickness in VR is believed to be due, at least in part, to the fact that the joystick on the controller is used to move in specific directions in VR, while the user's body is actually stationary.

[0005] To solve this problem, omnidirectional treadmills have been proposed. By physically walking on a treadmill to create corresponding movements in virtual reality, the discrepancy between the virtual and real worlds that causes motion sickness can be reduced, significantly enhancing overall immersion in the VR experience. An omnidirectional treadmill is a device that allows a user to walk or run in any direction, but does not move in space.

[0006] Various omnidirectional treadmills have been proposed in the art, some of which are already available on the market. Many of them use mechanical parts that actually move with the user's feet. Such designs are often expensive and have challenges with inertia because the moving parts cannot stop at the exact moment the user wants them to. To do this, the treadmill needs to be able to predict the user's thoughts / intentions. This is not yet possible, so the user moves slightly more than intended, which must be compensated for, resulting in uncomfortable correction movements. In other designs, a platform with a low-friction surface is combined with special low-friction shoes. The low-friction shoes allow the user to slide their feet backwards on the platform to mimic walking. To the user, this feels more like sliding than walking, and special shoes are required to use the treadmill. Additionally, this method is generally very noisy.

[0007] A freely rotating element on a platform that rolls at a mount under the user's foot when the user places their foot on it would solve both of the above problems and make it easier for the user to control the acceleration and speed of their movement while maintaining a relatively natural gait. In theory, this would be possible without special footwear. However, the sole should not have a deep profile, or it would get stuck between the balls.

[0008] Two types of rolling, omnidirectional treadmills have been proposed in the prior art. The treadmill consists of several freely rotating cylinders and a platform covered with rolling balls / spheres. The cylindrical geometry is not truly omnidirectional because the cylinders are each limited to a single axis of rotation along their length. This reduces the quality of movement the user experiences as they shuffle across the cylinders. In fact, this would not work at all with the proposed form factor of the device because every step would involve trying to rotate the cylinders about their axis of rotation. Since this is not possible, the user would become "stuck."

[0009] A spherical shape appears to be the most effective solution. Prior art solutions, such as Korean Patent Publication No. 10-2015-0128184 and U.S. Patent No. 10,101,805, propose the use of a spherical shape. However, the proposed concepts have fundamental problems that make practical implementation impossible. They include a central area on the platform that lacks any rotatable elements. These central areas provide a point where the user can establish a fixed connection to the floor surface.

[0010] However, these prior art solutions overlook the fact that providing a central gripping surface for stability also prevents the user from walking with a natural gait. In a normal walking motion, each foot is alternately placed forward and then pulled under and behind the user, causing the user to walk forward with the other foot during the final part of the motion. When a foot is prevented from moving behind the user's center of gravity, as is the case with friction using a central gripping surface in known solutions, the user's gait becomes awkward and unnatural. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-2015-0128184 [Patent Document 2] U.S. Patent No. 10,101,805 Summary of the Invention [Problem to be solved by the invention]

[0012] There is a need for a VR treadmill that enables precise omnidirectional movement while allowing users to walk safely with a natural and comfortable gait, further promoting immersion.

[0013] The present invention is viewed in this context. [Means for solving the problem]

[0014] As an omnidirectional treadmill device for supporting VR experiences, this device includes a concave platform with a regular arrangement of openings in which ball-bearing elements are installed, which extends across the platform's upper surface. The platform is supported by a frame, which is connected to a freely rotatable body support, supporting the user in a position above the platform's center point. The combined use of the concave surface, the ball-bearing-covered platform, and the body support allows for complete freedom of movement in a way that allows the user's feet to roll on the platform floor, which feels natural to the user. The rotating body support, sometimes referred to as the body support, can hold the user in place using, for example, a hip belt. However, this is not just for safety reasons. For an immersive and smooth running experience, it is desirable to lean into the belt. Essentially, you run against the belt. This ensures that your feet roll back by themselves.

[0015] Thus, according to one aspect, there is provided an omnidirectional treadmill apparatus comprising: a circular platform having a concave surface with a central point forming the bottom of its upper surface, the upper surface having a regular array of circular openings distributed over its area; a plurality of spherical ball bearing elements, each mounted in a corresponding opening in the upper surface whereby an upper portion of each ball bearing element is exposed and protrudes from the opening, and each ball bearing element is configured to rotate about any axis while mounted in the opening; a frame configured to support the platform; and a body support mechanism comprising a harness support connected to the frame via a freely rotatable connection and secured to secure a person's body in a predetermined position above the central point of the platform, while allowing the supported person to rotate in any desired direction via the rotatable connection to the frame.

[0016] In some embodiments, the frame includes a central support located below the center point of the platform. The body support mechanism includes a pair of arms pivotally connected to the central support and wrapped around the platform to hold the belt support in place above the platform. Harness support is understood to include all possible embodiments capable of holding the user in place. In addition to a belt, a vest or any other support device may also be used.

[0017] In some embodiments, the frame is divided into a lower frame portion that supports the device on the floor and an upper frame portion to which the running platform is attached. This division is necessary in some embodiments because the rotating body support arm requires free space between the two frame portions to be able to rotate.

[0018] In some embodiments, the openings in the top of the platform are cylindrical openings with a depth less than the diameter of the corresponding ball bearing elements, so that the ball bearing elements protrude through the openings. The openings do not necessarily have to be cylindrical. Any opening geometry that holds the balls in place and allows them to partially protrude can be used. This includes spherical openings.

[0019] In some embodiments, the openings in the top of the platform have anchoring devices to hold corresponding ball bearing elements in the openings with minimal friction. These can take the form of covers, among others, which desirably include holes so that the balls continue to protrude from the top. One embodiment includes balls that fit into the openings up to at least half the diameter of the balls. The holes in the covers can then have a diameter slightly smaller than the diameter of the balls. This ensures that the balls remain in their holes.

[0020] Additionally, the opening in the top of the platform can contain various smaller secondary ball bearing elements that are positioned below the larger primary ball bearing elements, which reduces friction on the primary ball bearing elements.

[0021] In some embodiments, the ball bearing elements are coated with a lubricating liquid.

[0022] In some embodiments, the ball bearing elements are arranged in concentric rings around a center on the top surface of the platform.

[0023] Various measures can be taken to reduce the force required to rotate the balls. One is, of course, the use of lubricants, as mentioned above. Furthermore, the smoother the balls, the lower the resistance. For example, a ball with precision grade G5 will roll more smoothly than one with precision grade G100. Friction can also be reduced further by placing the balls over small holes through which compressed air flows.

[0024] Furthermore, the ball can be rotated or suspended in various ways using an electric motor or compressed air flowing through a hole below the ball. When compressed air is used, the hole through which the air flows does not need to be exactly below the ball. This is also feasible, but would allow the ball to easily rotate in all directions. This has already been mentioned above. If the hole were instead placed toward the outside of the ball, the rotation of the inside of the ball would be supported, while the rotation of the outside would be slowed down. This can be useful to support the rotation at the right moment (at the beginning of the step) and even to slow down the rotation at the right moment (at the end of the step). When pushing off the surface at the end of the step, it is advantageous if the ball rotates as slowly as possible, or even not at all. This does not necessarily have to be achieved using an electric motor or compressed air. The balls can also be rotated using a magnetic field. They can be reliably slowed down by a magnetic field.

[0025] To achieve a braking effect when pushing off (at the end of the step), it can also be ensured that the ball at the edge of the platform can only rotate in the direction of the central point. This means that the ball only rotates when it starts the step, but does not rotate when it pushes off the platform again at the end of the step. This can be done in various ways. One possibility would be to change the shape of the ball so that it can only rotate in one direction. This can be achieved, for example, by providing a surface with features that only get stuck in certain positions by rotating in a certain direction.

[0026] Other objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, it being understood, however, that the drawings are designed by way of example only and are not intended to define the limits of the invention. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a first perspective view of an example configuration of a treadmill apparatus as viewed from above. [Figure 2] 2 is a second perspective view of the example configuration shown in FIG. 1, viewed from below. [Figure 3] FIG. 1 is a perspective view of an example treadmill apparatus configuration with ball bearing elements removed. [Figure 4] FIG. 10 is a close-up view of the top of the platform of an example treadmill apparatus configuration with the ball bearing elements removed. [Figure 5] FIG. 10 is a close-up view of the top of the platform of an example treadmill apparatus configuration with ball bearing elements installed. [Figure 6] FIG. 1 is a cross-sectional view of several ball bearing elements. [Figure 7] FIG. 1 is a top view of several ball bearing elements. [Figure 8] 1 illustrates a foot with several axes of rotation, the orientation and alignment of which are merely examples. DETAILED DESCRIPTION OF THE INVENTION

[0028] In the figures and detailed description, common reference numerals are used to identify common elements. Those skilled in the art will readily appreciate that the above figures are examples and that other structures, modes of operation, sequences of operation, and elements / functions may be provided and implemented without departing from the features and characteristics of the invention as set forth in the claims.

[0029] Exemplary embodiments are described in detail below to illustrate the principles of the present invention. The exemplary embodiments serve to illustrate aspects of the present invention, but the present invention is not limited to any one embodiment. The scope of the present invention includes numerous alternatives, modifications, and equivalents, and is limited only by the claims.

[0030] In order to provide a better understanding of the present invention, numerous specific details are provided in the following description. However, the present invention may be practiced according to the claims without some or all of these specific details. For the sake of clarity, detailed descriptions of technical materials known in the art related to the present invention are omitted.

[0031] The terminology used herein is used only to describe particular embodiments and should not be construed as limiting the present invention. As used herein, the term "and / or" includes all combinations of one or more of the associated listed elements. As used herein, the singular forms "one," "a," and "the" include both the plural and the singular unless the context clearly indicates otherwise. It should be further understood that the terms "comprising" and / or "containing" and / or "including," when used herein, specify the presence of particular features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.

[0032] The presented treadmill allows omnidirectional motion for users walking with a natural gait by having a concave platform with an upper surface completely covered by a series of ball-bearing elements that hold and support the user at a point in space above the center of the platform with a rotatable body support connected to a frame below. This allows users to walk and even run in any direction without risk of injury, with motion that feels natural enough to make users momentarily forget they are in a VR experience.

[0033] 1 and 2, first and second perspective views of an example configuration of a treadmill apparatus 100 according to the present description are shown from above and below.

[0034] As can be seen, the device 100 comprises a circular platform 102 with a concave profile. The top surface 104 of the platform 102 is completely covered by a regular row or area of ​​ball bearing elements 106 that are placed in openings 107 in the top surface 104. In this example, these openings 107 and ball bearing elements 106 are arranged concentrically around a central point 108 of the platform 102, although other arrangements are also contemplated. The only restrictions are that each of the ball bearing elements 106 must be close enough to allow the feet of the held person, hereafter also referred to as user 115, to roll seamlessly over them, and that the ball bearing elements 106 must cover the top surface.

[0035] As used herein, the term "top surface" refers exclusively to the portion of the platform on which the user 115 walks while interacting with the treadmill. The statement that the entire surface is covered means that both the central region and the curved sides of the top surface are covered.

[0036] Each ball-bearing element 106 is mounted in a corresponding opening 107 in the top surface, leaving the upper portion of each ball-bearing element 106 exposed and protruding from the opening 107. The ball-bearing elements 106 are mounted so that they can freely rotate about any axis within their openings. Various types of openings 107 can be used, ranging from simple cylindrical or spherical shapes whose depth is less than the diameter of the balls, to more complex arrangements in which smaller balls roll with the main balls to reduce friction within the opening 107. Figures 6 and 7 show example arrangements of the ball-bearing elements / balls 106 and smaller ball-bearing elements / balls 109. Figure 6 shows a cross-section, and Figure 7 shows a top view. Many other arrangements are possible. Figure 6 also shows the configuration of the cover 111.

[0037] Platform 102 is supported by a frame. In this example, the frame includes a lower frame portion 110, which supports the entire treadmill on the floor, and an upper frame portion 120, which connects platform 102 to lower frame 110. The upper and lower frames are connected to each other by an axle 113, which passes through the center of a ball bearing located inside component 118. This ball bearing enables rotation of components 118, 112, 114, 116, 117, and 122, i.e., rotation of the body support.

[0038] To ensure that the user 115 does not lose balance on the platform's ball bearings and can freely and safely walk and run in any direction on the treadmill without fear of falling and suffering bodily harm, the treadmill 100 also includes a body support mechanism that holds the user 115 in place over the center point 108 of the platform 102.

[0039] In this example, the body support mechanism takes the form of a harness mount 116. The harness mount is pivotally connected to a frame below the platform 102 via a pair of arms 114 and a set of radially arranged supports 112. Together, the supports 112 form a fixed point above the platform 102 that can rotate with the user 115 while holding the user in place. The arms 114 are connected to the harness mount 116 via supports 122, and a harness 117 can be worn at the front.

[0040] 1 may or may not be integrated into the belt holder 116, but must hold the user 115 in place by some means.

[0041] FIG. 3 shows another perspective view of the treadmill 100, in which the ball bearing elements 106 have been removed from the platform.

[0042] In another example, the treadmill may be supplied with the ball bearing elements 106 already installed in the openings 107 and a separate cover to hold them in place. This way, the purchaser does not have to insert the balls themselves. If cover 111 is used, as it should be, no additional cover is required for shipping, since the balls are held in the holes by cover 111.

[0043] 4 and 5 show close-up views of the top surface of the platform in an example configuration with the ball bearing elements removed (FIG. 4) and installed (FIG. 5), respectively.

[0044] The curvature of the concave platform 102 means that as the user shifts their weight, gravity rolls the user's front foot 115 down over the ball element, returning the user to the center point. After passing the center point, the foot then rolls up the rear slope through a natural gait range. The other foot follows the same offset movement pattern as in normal running or walking. In this way, the user 115 can take a full, natural step. When the user 115 turns, the arms of the body support rotate together and around the center of the platform to keep the user 115 safe on the treadmill.

[0045] Various means are used to track the user's motion and translate that motion into corresponding VR motion. Camera tracking, using multiple cameras positioned around or mounted on the treadmill, is one way to track motion. Other methods are possible, such as IMU sensors, SLAM trackers, UWB technology, electromagnetic tracking, rotation measurement devices, Vive base stations, and others. Several methods can also be combined with each other. The goal of this motion tracking is preferably to track and communicate motion as the shoe / foot's position and rotation in three-dimensional space. Looking at the position and rotation over time yields the foot's motion. The more technical and commonly used term for this form of tracking is 6DOF tracking. 6DOF stands for six degrees of freedom, which means that the exact position and full orientation in space in all three spatial axes / dimensions (X, Y, Z) and the rotations (roll, pitch, yaw) about each of these axes are tracked. In theory, only rotation around the Z-axis (Figure 8), commonly called yaw, is required to control the direction of movement in VR applications through the feet. Therefore, 4DOF tracking, consisting of spatial position in all three spatial axes / dimensions (X, Y, Z) (=3DOF tracking) as well as the yaw axis (Z-axis in Figure 8), is theoretically sufficient. However, considering that in practice, most tracking systems only track in either 2DOF, 3DOF, or 6DOF, another term is 6DOF tracking, or three-dimensional tracking. However, these terms can also refer to only 4DOF.

[0046] An emulator can be programmed with information about the foot position and rotation. The emulator converts the information about the foot movement into joystick movement, or in other words, movement in a VR application. The emulated joystick movement in this case consists of two components: the direction of the joystick movement and the joystick displacement amplitude, which measures how far the joystick is moved from its neutral position (center point).

[0047] One advantage of this 6DOF tracking approach is that the feet can be used directly to control the direction of the emulated joystick. To do so, both feet preferably have a forward-facing vector, pointing from the heel toward the tip of the foot, like the Y axis in Figure 8. The two forward-facing vectors are then preferably combined to form an omnidirectional vector. This can be done by adding the vectors or by creating a mean / average vector of the two vectors.

[0048] Information about the foot's motion in three-dimensional space is also useful for emulating backward motion. This allows for determining when the foot is in the air and when it is in contact with the treadmill surface. If the difference between a foot in the air and a foot on the treadmill surface is too inaccurate for simple motion tracking using a camera, full tracking, or other 6DOF tracking methods, other sensors, such as pressure, distance, or contact sensors, can also be used.

[0049] When the user 115 is running forward, the user moves their feet from the front or center to the back on the treadmill surface. However, when the user 115 is running backward, the user moves their feet from the center to the front on the treadmill surface. This is called motion on the treadmill surface. These must be distinct from airborne motion. This is because when running forward, the airborne motion between steps is also back-to-front. When running backward, the airborne motion between steps is also front-to-back. This means that it is more difficult to understand the difference between the two types of motion when one cannot distinguish between airborne motion and motion on the treadmill surface. Forward motion can thus be initiated by moving at least one foot forward in the air or by moving it backward on the treadmill surface. Backward motion can thus be initiated by moving at least one foot backward in the air or by moving it forward on the treadmill surface.

[0050] If it is not possible or desirable to reliably distinguish between airborne and treadmill motion, alternative approaches for backward motion are also possible. On the one hand, the upward and downward tilt of the foot can be considered to distinguish when forward or backward motion is being performed. Foot tilt is not the same as controlling the direction of motion through foot rotation as described above. When controlling the direction of motion, the tilt / rotation of the foot to the left and right is considered. Instead, what is meant here is the upward and downward tilt / rotation, which changes over the course of a step and can thereby be used to distinguish between forward and backward motion.

[0051] This difference is shown in Figure 8. Tilting / rotating the foot up and down refers to rotation around the X axis. Tilting / rotating the foot left and right to control the direction of movement refers to rotation around the Z axis. It is not significant that the right foot is shown in Figure 8; the left foot would also be fine.

[0052] Another alternative is to take advantage of the fact that steps for forward exercise on a treadmill generally begin in front of or above the midpoint and end only behind the midpoint. In contrast, steps for backward exercise generally begin midway and end further forward, but the posterior region is not used. This distinction can be used to distinguish between forward and backward exercise.

[0053] Information about foot movement in three-dimensional space is also useful for emulating lateral movements. On the one hand, one or both feet can naturally be rotated laterally. Since the overall direction of movement is controlled by the orientation of the feet, rotating one or both feet sideways results in a rotation of the overall direction of movement to the side. The angle at which the lateral movement increases can also be specified. For example, if the right foot rotates more than 70° to the right, an enhanced lateral movement can be initiated. Although the overall direction vector is already rotated to the right in this case, the initiation of enhanced lateral movement means that this rotation is increased to, for example, approximately 90° forward.

[0054] Omnidirectional treadmills are used with 6DOF tracking technology that not only detects forward and backward motion, but also detects the complex lateral movements of the user's feet and accurately translates these into virtual reality applications. This is made possible by continuously measuring the position of the feet and their direction of movement, which allows various methods to be used to determine the angular relationship for the lateral movement.

[0055] One method for lateral movement is to measure the angle between the foot's forward vector and the movement direction vector. The forward vector is the vector that runs from the back of the foot to the toes, i.e., the Y axis in Figure 8. The movement direction vector is the vector that is created when drawing a continuous vector between two positions of the foot at two points in time. If the lateral movement is performed with an angle between the foot's forward vector and the movement direction vector that exceeds a predetermined threshold, this movement will be emulated as a lateral movement with a corresponding angle in the VR application.

[0056] Another way to obtain the angle for lateral movement is to measure the angle between the omnidirectional vector (from the combined forward-facing vectors of both feet) and the foot movement direction. The movement direction is created when drawing a continuous vector between two positions of the foot at two time points. If this angle exceeds a certain threshold, a lateral movement with the corresponding angle will occur in the VR application.

[0057] A third method to obtain the angle for lateral movement is to use the angle between the omnidirectional vector (from the combined forward vectors of both feet) and the vector connecting the center of the treadmill to the foot position. If this angle exceeds a certain threshold, a lateral movement with the corresponding angle will occur in the VR application.

[0058] In all three approaches to measuring the angle of lateral movement, the measurement is continuous, allowing the user to move laterally at any angle.

[0059] In all three approaches, the omnidirectional vector created by combining the forward-facing vectors of both feet serves as the starting point (zero point) for setting the measured angle and for making the corresponding directional change. For example, if a lateral movement is detected at a 50° angle, the omnidirectional vector is adjusted by this angle, resulting in a 50° lateral movement relative to the omnidirectional vector in the VR application.

[0060] Thus, if a lateral movement is detected to exceed a certain lateral movement angle threshold, the original omnidirectional vector is temporarily ignored, and the omnidirectional vector jumps by the measured angle, i.e., 50° in the given example. After the angle between the lateral movement and the omnidirectional vector falls below a certain threshold, the system switches back to the original omnidirectional vector, or the omnidirectional vector jumps back so that it again becomes the combined vector of the forward vectors of both feet. This ensures that the user's basic orientation and original movement direction are maintained in the VR application as soon as they resume normal forward or backward movement.

[0061] The system also makes it possible to utilize a combination of the above approaches to ensure optimal accuracy and user experience, allowing for flexible adaptation to different VR applications and individual user preferences.

[0062] When moving laterally, it also makes sense to distinguish between a foot in the air and a foot on the treadmill surface. This is because in VR applications it is also possible to distinguish in which direction the user is moving. However, instead of distinguishing between forward and backward, a distinction is now made between left and right. Leftward movement can therefore be initiated by moving at least one foot in the air from right to left, or by moving it on the treadmill surface from left to right. Rightward movement can therefore be initiated by moving at least one foot in the air from left to right, or by moving it on the treadmill surface from right to left.

[0063] The emulator accurately calculates foot velocity and, using a threshold, determines joystick amplitude and filters to avoid undesired stalls due to the foot changing direction at the end of a step. Foot velocity is accurately calculated by tracking with at least a 3DOF tracker, which measures the foot's position at different times. This velocity is then determined by dividing the change in position over time. This is done by calculating the difference between two consecutive positions (in X, Y, and Z coordinates) and dividing these differences by the time difference between the two measurements. The result indicates how fast the foot is moving. This method is significantly more accurate than velocity calculations based on acceleration data (common in the art / competitors), because velocity calculations based on acceleration data require integrating acceleration over time to obtain velocity. This integration process inevitably introduces accumulated error, especially when the acceleration signal has noise or bias. Every small error in the acceleration measurement results in a larger error in the velocity calculation over time.

[0064] The emulator is configured to calculate the amplitude of the joystick displacement (joystick displacement amplitude) based on the user's velocity measured as described above, so that the user's velocity in the associated virtual reality application is linearly converted to the joystick displacement amplitude. In this conversion, 0% joystick displacement corresponds to a player movement of 0 km / h in the VR application, while 100% joystick displacement corresponds to the user's maximum velocity in the associated VR application. If the maximum possible velocity in the VR application, linearly converted to the velocity, is at least equal to the maximum velocity the user can actually achieve on the treadmill, the entire range of velocity is covered, and the user's velocity can therefore be accurately translated from minimum to maximum for the VR application. In this way, for example, if the maximum possible velocity in the VR application is 50 km / h, the user can run as fast as they want, and their velocity will be accurately transmitted, even at full speed. For example, if a user only runs at 25 km / h, the software emulates a 50% joystick amplitude, which is communicated to the VR application as 50% of the maximum possible speed (50 km / h), thus also resulting in a speed of 25 km / h in the VR application. Because many VR applications allow for a slower maximum speed than most people can achieve on a treadmill, the VR application can be modified to increase the maximum speed, thereby enabling a full range of speeds. This modification is not necessary for many VR applications because only a limited maximum speed is perfectly acceptable or desirable in the application. For example, if the maximum speed in a VR application is only 10 km / h, the joystick amplitude translation in the emulator can easily be adjusted so that 100% joystick amplitude is reached exactly when the user also reaches 10 km / h on a treadmill.

[0065] The emulator is also configured to adjust the joystick amplitude to avoid common joystick deadzones in games, e.g., a 20% deadzone. This is achieved by adjusting the start of the joystick amplitude (0%) to the edge of the deadzone, effectively ignoring the first 20% of joystick movement and translating subsequent movement accordingly.

[0066] The position of the feet in three-dimensional space (3DOF) is not only important for accurately determining speed. It is also required to define specific regions of the treadmill, such as zones with specific attributes. For example, by combining the forward vectors of both feet to control the omnidirectional vector, the feet typically swing slightly outward as they push off the treadmill surface at the end of each step. This swinging motion shifts the omnidirectional vector left and right when the user simply wants to walk straight. To dampen these undesired motions while maintaining accurate directional control of the feet, it is desirable to designate a region where foot rotation has little (or no) effect on the omnidirectional vector. This region's positioning, shape, and damping strength are desirably customizable to suit the user's individual needs. Additionally, this region must rotate with the omnidirectional vector to always maintain the same orientation relative to the user. Typically, this region is located in the rear half of the treadmill (considering the omnidirectional vector pointing forward). This is because it is in this area that the foot performs a pivoting movement when pushing off the treadmill to take a step.

[0067] Ultimately, it makes sense to implement some or all of the emulator and possibly track the movement with the help of a neural network / artificial intelligence. This means, on the one hand, that information about the foot's movement and rotation in a first position can be obtained using computer vision. In other words, it means tracking the foot. Next, the emulator or parts of it can also be implemented using a neural network / artificial intelligence. The neural network can be trained to distinguish between various types of movement, such as forward, backward, or sideways. It can also be trained to determine omnidirectional movement based on various factors. Again, foot alignment is the most important factor here.

[0068] Other methods for all the tracking and emulation procedures listed are possible.

[0069] By tracking foot movements in three dimensions, it is possible to implement so-called "full-body tracking." For this purpose, it would make sense to track additional points, such as the knees or hips. However, it would also be possible to ensure that foot movements are reflected in the VR application without these additional points. In this case, however, it would probably be better to call it "foot tracking." This would allow the user or another user 115 to see the user's feet and their movements, such as dancing or kicking, in the VR application. It is important to understand that only the movements of the feet or body parts themselves are transmitted. These movements must be distinguished from movements generated from emulation. Emulated movements are the movements of the user 115 in virtual space. In other words, they are the movements of the user 115 from point A to point B. Therefore, these movements must be considered independent of each other. For example, if you want to dance in real time, you can transfer only the foot movements. However, in most cases, only emulated movements are required, since most applications involve getting from point A to point B. In other words, it involves moving through a virtual world. Of course, both foot movement and emulated movement can be transferred.

[0070] It is therefore proposed that the omnidirectional treadmill device have a means to detect the foot movements of the user 115, including rotation, in three-dimensional space (4DOF / 6DOF tracking). The hardware for this can be attached or placed on the shoe or platform, or at any location. Various options can also be combined.

[0071] It would be advantageous if the device were designed to distinguish between airborne movement and movement on a treadmill surface, and to this end the platform or shoe may have at least one additional sensor that detects when the user's foot 115 contacts the platform.

[0072] An emulator that converts information about foot movements into joystick movements for control in VR applications would be advantageous.

[0073] The emulator is able to determine the direction of movement based on an omnidirectional vector generated by combining the forward-facing vectors of both feet.

[0074] It is advantageous if the emulator emulates movement in a forward, backward or sideways direction based on foot movement and / or tilt / rotation and / or foot contact with the treadmill.

[0075] It is also proposed to use neural networks or artificial intelligence for movement tracking and / or emulation.

[0076] It is advantageous if the device enables full body tracking or foot tracking, so that in addition to the user's feet 115, other points on the body can be tracked, such as the knees or hips.

[0077] Unless otherwise defined, all terms (including technical terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It is further understood that terms as defined in dictionaries in common usage should be interpreted to have a meaning consistent with their meaning in the context of the relevant prior art and this disclosure, and should not be interpreted in an idealized or overly formal sense except as expressly defined herein.

[0078] The illustrated embodiment is exemplary and non-limiting. Although a particular configuration of a service provider customer experience verification system has been described in particular terms with reference to the illustrated embodiment, it should be understood that the invention can be applied to various solutions consistent with the scope and spirit of the claims. There are many alternative ways of implementing the invention.

[0079] It is to be understood that the embodiments of the invention described herein are merely illustrative of the application of the principles of the invention. Reference to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.

Claims

1. An omnidirectional treadmill device (100), comprising: a circular platform (102) having a concave profile with a central point (108) forming the bottom of an upper surface (104), said upper surface (104) having a regular row of circular openings (107) formed across said upper surface (104); The omnidirectional treadmill device (100) allows omnidirectional movement of a user walking with a natural gait, the circular platform (102) having the upper surface (104) that is completely covered with a series of ball bearing elements with as small a gap as possible and arranged around the central point (108) of the upper surface (104) of the circular platform (102), the ball bearing elements allowing for seamless rolling of the foot; By covering the entire surface, it is meant that both the central region and the curved sides of the upper surface are covered; the omnidirectional treadmill apparatus (100) comprises a plurality of spherical ball bearing elements (106), each ball bearing element (106) seated in a corresponding opening (107) in the upper surface (104) such that an upper portion of each ball bearing element (106) is exposed and protrudes from the opening (107), and each ball bearing element (106) is configured to rotate about any axis while seated in the opening (107); The omnidirectional treadmill apparatus (100) comprises a frame (110, 120), the frame (110, 120) being configured to support the circular platform (102) and being divided into a lower frame portion that supports the omnidirectional treadmill apparatus (100) on a floor surface, and an upper frame portion to which the platform is attached; the omnidirectional treadmill apparatus (100) comprises a body support mechanism comprising a harness attachment (116) connected to the frame (110, 120) via a freely rotatable connection and configured to secure a person's body (115) in a predetermined position above the central point (108) of the circular platform (102), while allowing the supported person (115) to rotate in any desired direction via the rotatable connection to the frame (110, 120); The circular platform (102) is supported by the frame, the lower frame portion (110) supports the entire treadmill on the floor, and the upper frame portion (120) connects the circular platform (102) to the lower frame portion (110); The upper and lower frame portions are connected to each other by a stem (113); The axle (113) extends through the center of a ball bearing, which allows the body supports (118, 112, 114, 116, 117, and 122) to rotate relative to the circular platform (102); An omnidirectional treadmill device (100).

2. 2. The omnidirectional treadmill apparatus of claim 1, wherein the frame includes a central support positioned below the central point of the circular platform, and the body support mechanism includes at least one arm rotatably coupled to the central support and surrounding the circular platform to hold a belt support in place above the circular platform.

3. The omnidirectional treadmill apparatus (100) of claim 1, wherein the harness attachment portion (116) comprises an integrated belt (117).

4. 2. The omnidirectional treadmill apparatus (100) of claim 1, wherein the frame (110, 120) is divided into a lower frame portion (110) that supports the apparatus on a floor surface and an upper frame portion (120) that holds the circular platform (102) in place.

5. 2. The omnidirectional treadmill apparatus of claim 1, wherein the openings in the upper surface of the circular platform have a depth less than the diameter of the corresponding ball bearing elements, whereby the ball bearing elements protrude therefrom.

6. 2. The omnidirectional treadmill apparatus of claim 1, wherein the openings in the top surface of the circular platform include mounting devices that hold each of the ball bearing elements to the apparatus with minimal friction.

7. 2. The omnidirectional treadmill apparatus (100) of claim 1, wherein the openings (107) include a plurality of smaller secondary ball bearing elements (109) positioned below the primary ball bearing element (106) of each opening (107).

8. The omnidirectional treadmill apparatus (100) of claim 1, wherein the ball bearing elements (106) are coated with a lubricating liquid.

9. 10. The omnidirectional treadmill device (100) of claim 1, comprising an emulator that converts information about foot movements into joystick movements for control in VR applications.

10. 10. A method of using the omnidirectional treadmill apparatus of claim 1, wherein the positional and rotational movements of the shoe or foot in three-dimensional space are tracked and observed over time.

11. The method of claim 10, wherein an emulator is used to determine the direction of movement based on an omnidirectional vector obtained by combining the direction vectors of both feet pointing from the heel to the toe of the foot.

12. 11. The method according to claim 10, wherein information about the position and rotational kinematics of the shoe or foot in three-dimensional space is also used for the emulation of backward kinematics.

13. The method of claim 10 , wherein additional sensors, such as pressure, distance, or contact sensors, are used to determine when the foot is in the air and when the foot is in contact with the treadmill surface.

14. 11. The method of claim 10, wherein information about the movement is also used for emulating lateral movements, regarding the position and rotation of the shoe or foot in three-dimensional space.

15. 11. The method according to claim 10, wherein neural networks or artificial intelligence are used for the movement tracking and / or emulation.

16. The method of claim 10 , wherein full body tracking or foot tracking is enabled by default.

Images