EXERCISE DEVICE WITH FORCE SENSORS TO ESTIMATE FOOT POSITION

Description

RELATED APPLICATION DATA

This application claims the benefit of U.S. Provisional Patent Application No. 63/354,123 filed on Jun. 21, 2022, the contents of which are incorporated herein by reference as if explicitly set forth.

TECHNICAL FIELD

This patent application generally relates to the field of exercise equipment. More specifically, this patent application relates to determining a user's foot position before and during an exercise.

BACKGROUND

Exercise is known to be a big enabler of physical and mental well-being. Resistance training, also known as strength or weight training, has significant health benefits, but can also be challenging for a typical person to do correctly or well. Exercising the whole body is good for overall wellbeing, rather than just exercising a few isolated muscles. Compound exercises that engage multiple muscle groups are the most beneficial and time-efficient exercises. Resistance training can also be used for cardiovascular training when done with relatively lower resistance at relatively higher reps over a relatively longer period of time.

There are many known types of exercise equipment for doing cardiovascular training in an indoor setting such as treadmills, stationary spin bikes, rowing machines, stair climbers etc. that have some sort of mechanism to vary the resistance mechanically or magnetically or electro-magnetically.

Resistance training is typically performed by doing body-weight exercises, using free weights, using resistance stretch bands, or using weight-training machines with weights driven through stabilized rigid linkages, or cable machines with weights driven through cables and pulleys, but these suffer from various disadvantages. For body-weight exercises, the resistance doesn't always match the strength of the muscles being engaged. Working with free weights can be potentially hurtful, damaging to the surrounding environment, noisy, or require heavy and expensive safety equipment. Cable machines and weight-training machines require a significant amount of space. While one cable machine can do many different exercise, weight-training machines are usually made for a specific exercise requiring a significant number of different devices to provide a full body workout. Stabilization inherent in weight-training machines can prevent the engagement of all the muscle groups need to stabilize movements under load in real life activities. Resistance stretch bands usually act as linear springs, in which the force increases with extension, so the force is not freely and fully controllable. Some magnetic and flywheel mechanisms exist that can vary the resistance to some extent, but the resistance usually increases with increase in speed of the movement and is thus not sufficiently controllable.

There has been growing interest in exercising at home, instead of commuting to the gym and sharing equipment. Exercise equipment made for the home needs to be affordable, quiet, time-efficient, light weight, portable and space-efficient. It can however be a challenge to stay consistent enough to reap the health benefits. Users can be kept motivated through various digital methods like content and feedback on a digital screen, data logging, progress tracking, live group classes, video communication with a coach and/or other users.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some examples of the present disclosure are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numbers indicate similar elements. To easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.

FIG. 1 is a perspective view of an exercise device, according to some examples.

FIG. 2A and FIG. 2B show two configurations of the exercise device of FIG. 1 in use, according to some examples.

FIG. 3A, FIG. 3B and FIG. 3C illustrate strength exercises that can be performed using the exercise device according to some examples.

FIG. 4A and FIG. 4B show two configurations of a second version of the exercise device, according to some examples.

FIG. 5 is a diagram illustrating the location of a foot on each of a left foot plate and right foot plate of an exercise device, and the relationship between the forces applied to each plate.

FIG. 6 is a schematic plan view of an exercise device, according to some examples.

FIG. 7 is a plan view of an exercise device, according to some examples.

FIG. 8 is a schematic diagram illustrating a top view of the location of a foot on the platform of the exercise device of FIG. 7, and the relationship between the forces applied to the platform.

FIG. 9 is a plan view of the platform of the exercise device of FIG. 7, according to some examples.

FIG. 10 is a plan view of the right side of the platform of FIG. 7, according to some examples, illustrating the right LED indicators 706.

FIG. 11 is an exploded perspective view of the configuration and mounting of one of the force sensors of the exercise device of FIG. 7 and FIG. 8, according to some examples.

FIG. 12 illustrates the arrangement of components inside the exercise device to provide cable tension and management according to some examples.

FIG. 13 is an underside view of the platform 702, according to some examples.

FIG. 14 is a flowchart illustrating a method of operating the exercise device according to some examples.

FIG. 15 is a perspective view of the cable guide of FIG. 12 according to some examples.

FIG. 16 is a front view of the cable guide of FIG. 12 according to some examples.

FIG. 17 is a side perspective view of the cable guide of FIG. 12 according to some examples.

FIG. 18 is a top view of the retraction mechanism of FIG. 12 according to some examples.

FIG. 19 is a perspective view of a retraction mechanism according to some examples.

FIG. 20 illustrates an electrical control system and related components for the exercise device according to some examples.

FIG. 21A is a graph that illustrates the relationship of the height of the bar or handle above the platform and the perceived weight experienced by the user, according to some examples.

FIG. 21B is a graph that illustrates the perceived weight experienced by the user based on direction of motion of the cables, according to some examples.

FIG. 21C is a graph that illustrates the perceived weight experienced by the user based on the range of motion of the cables 202 during an exercise, according to some examples.

FIG. 22 illustrates a display that may be shown on a related display device during use of the exercise device, according to some examples.

FIG. 23 illustrates a system including an exercise device, a server, and various client devices according to some examples.

DETAILED DESCRIPTION

FIG. 1 is a perspective view of an exercise device 102 according to some examples. The exercise device 102 includes a base comprising a chassis 104 and a platform 106, spaced-apart left and right side pods 108, wheels 110, and attachment points 112 to which a workout element, such as handles 114 or a bar 116, can be attached for use in resistance training. The exercise device 102 will typically be placed on the ground, although it can be mounted to the wall or another structure. As will be described in more detail below, the attachment points 112 are coupled to two cables 202 that are housed in the side pods 108.

The top of the platform 106 is planar and fairly low in height (in the range of 2-3 inches) when the exercise device 102 is on the ground, which mitigates any risk or fear of falling off of a high step during exercise and makes the exercise device 102 safer. A user can stand, sit, kneel, or lie on the platform 106 depending on the exercise, with the user's weight holding the exercise device 102 down while the user lifts in an upward direction using the bar 116 or the handles 114 as shown in FIG. 3A, FIG. 3B and FIG. 3C. Additionally, since the bar 116 overlaps the side pods 108 on both sides, if a user drops the bar 116 it will hit the side pods 108 before it hits the user's feet.

The chassis 104 is supported by wheels 110. There may be two wheels 110 on just one side so that the exercise device 102 can be picked up from the other side to engage the wheels 110, which permits the exercise device 102 to be moved into and out of storage like a rolling suitcase, without having to lift the full weight of the exercise device 102. In other examples, the device may have four wheels 110 (two on each side as shown in FIG. 1). In some cases, the wheels do not extend below the bottom of the chassis 104 and require that a side of the exercise device 102 be lifted up on one side to engage the wheels on another side.

In other examples, the wheels 110 are spring-loaded and protrude below the chassis 104 when the exercise device 102 is not in use, but are pushed up into the chassis 104 when a certain minimum weight of the user rests on the platform 106, which ensures that the exercise device 102 is securely engaged with the ground when used. This provision of wheels 110 permits the exercise device 102 to be rolled away conveniently, for storage under a bed or couch for example.

In the case of spring-loaded wheels 110, one or more of the wheels 110 may be attached to a sensor to detect whether it or they are pushed up into the chassis by the user's weight. Detection of these two states of the wheels 110 may be used to enable full functioning of the exercise device 102 when the wheels are retracted and to disable full functioning of the exercise device 102 when the wheels are extended. In particular, the exercise device 102 can use these two states to disable tension in the cables provided by the motors 1212 (see FIG. 12) when the user's weight is not on the platform, so that if the user steps off the platform 106 during an exercise or is not on the platform when a handle 114 or the bar 116 is lifted, the platform 106 will not be lifted into the air under the power of the motors. Alternatively, sensors could be provided in the platform 106 or elsewhere to detect the user's weight, to enable or disable functioning of at least the motors 1212 based on detecting the presence or absence of the user's weight.

In other examples, the wheels 110 on one or both of the sides may be casters, or there may be a single caster wheel on one side and two normal wheels on the other side. Providing at least one caster wheel allows the user to rotate the exercise device 102 while on the ground, which helps in moving the exercise device 102 under beds and couches that may have little clearance under them.

FIG. 2A and FIG. 2B show two configurations of the exercise device 102 in use, according to some examples. As shown in FIG. 2A and FIG. 2B, by attaching the bar 116 or the handles 114 to the attachment points 112, the cables 202 can be pulled up vertically or at a certain angle from vertical, under tension that is provided by two motors, one in each side pod 108. The tension in in each cable 202 provides the resistance for the training. The exercise device 102 is designed to mimic free weights like barbells, dumbbells, and so forth.

As shown in FIG. 2A, when the bar 116 is attached to the cables 202, a user can train as if the bar 116 is a barbell. Or, as shown in FIG. 2B, when the two handles 114 are attached to the attachment points 112, they can act independently to be used to train like two dumbbells. Other attachments may also be provided, like a short bar with one attachment point in the middle, a waist belt with two attachments on each side, an ankle/wrist strap with one attachment point, and so forth, can also be used to connect to one or both of the attachment points 112 to provide a variety of different workouts.

Hundreds of different exercises can be done to create a full-body workout using a barbell and two dumbbells. Accordingly, the exercise device 102 can be used to do many different exercise for full body resistance training. Since the two cables 202 can operate independently and with different tension forces, which can also vary dynamically, a user can do many different balance and stabilization resistance exercises with the exercise device 102 as well.

FIG. 3A (bicep curls), FIG. 3B (deadlift) and FIG. 3C (overhead press) illustrate three different strength exercises that can be performed by a user 302, using the exercise device 102 according to some examples.

FIG. 4A and FIG. 4B show two configurations of a second version of the exercise device, according to some examples. The exercise device 402 in this case has rectangular side pods 408. Each side pod 408 has a slot 404 defined therein that permits side-to-side movement of each cable 418 in use. A Y-shaped bar holder 406 is rotatably coupled to each side pod 408 by means of a bracket 410. The bar holders 406, when in the vertical position shown in FIG. 4A, hold a bar 416 at a defined height above the platform 412, which makes it easier for the user to place their feet in alignment under the bar 416, as well as to permit more convenient grasping of the bar without having to lean all the way down to pick the bar off the platform or off the side pods 408. A user can break form if they need to lean all the way down to the pick the bar 416 up off the platform 412, which may lead to injury over a period of time.

Foot position relative to the points at which the cables 418 exit the side pods 408 is important for optimal form and to reduce the risk of injury. For example, if the bar 416 had to be picked from the platform 412, a user would not have room to locate their foot right under the bar 416 initially, which would make them stand further backwards on the platform next to the bar 116. This would either require the user to move forward after the bar 416 had been raised, or do the exercise with feet not in an optimal position, which will in turn cause the user to do the exercise in a nonoptimal form.

As shown in FIG. 4B, the bar holders 406 can be rotated out of the way to a horizontal position adjacent to the side pods 408 to facilitate unobstructed use of the handles 114 with the exercise devices 402.

Also shown in FIG. 4A and FIG. 4B are stops 414 above the wheels 420 on the side pod 408 on the left side, to assist with moving and storage of the exercise device 402.

As illustrated in FIG. 4B, the platform 412 in some examples comprises a left foot plate 422 and a right foot plate 424. Located underneath each of the left and right foot plates 424, 422 at each of their corners are force sensors that can be used to determine the forces applied to the two plates by the user's feet, as well as the position of each of the user's feet as will be described in more detail below. When the user is not holding the bar 416 or one of the handles 114, the sum of the forces will equal the weight of the user. During exercise, the forces on the left foot plate 422 and right foot plate 424 will give an indication of the user's weight plus the forces applied by the user's left and right hands respectively.

Force sensors in a platform can be commonly seen in electronic body weight scales and dual force-plate setups in physical therapy equipment, to measure the force under each foot. Patients may have a musculoskeletal problem or a strength mismatch between the two sides of the body which ends up creating different force/weight readings on each side when standing still or when performing an exercise. This can further exacerbate the physical wellbeing and/or ability to perform functional movements. The use of force sensors to determine applied forces in physical therapy can provide feedback to the therapist and the patient, and can assist with effective physical therapy.

In the disclosed floor-based platform (exercise device 102 and exercise device 402), force sensors are used under the foot plates 422, 424 to enable the sensing of mismatches in forces between the two sides of the body during exercising. Such data can then be used to drive different forces in the two cables that create the load for the exercise. A force differential can be determined by or used as an input to the embedded processor 2012, to either signal the corresponding retraction mechanism 1206 (see FIG. 12 and FIG. 18) to provide more load on the side that is taking less weight, or reduce the weight on the side that is weaker and needs to exercise at less weight. This is especially relevant and useful in dynamic tension devices such as the exercise devices 102 and 402 that are not driven by fixed free weights, but are driven by an electromagnetic mechanism that can change force rapidly and independently on both two sides.

Providing a further benefit, the current system also measures the force produced by the four sensors of each plate 424, 424 independently. The sum of the four measured forces provides the total force value on each side, which is useful as described above, but apart from that the ratio of the forces measured by the four sensors on a foot plate also provides valuable information about the location of the foot compared to the corners of the foot plate where the force sensors are located.

FIG. 5 is a diagram illustrating a top view of the location of a foot on each of the left foot plate 422 and right foot plate 424, and the relationship between the forces applied to each plate. In some examples, each foot plate includes four force sensors F1L 502, F2L 504, F3L 510 and F4L 508 for left foot plate 422 and F1R 512, F2R 514, F3R 520 and F4R 518 for right foot plate 424. Since FIG. 5 is a top view, an “upper” force sensor in FIG. 5 corresponds to a front sensor in FIG. 4B, with a “lower” force sensor in FIG. 5 then corresponding to a rear sensor in FIG. 4B. Also, for ease of illustration, left foot plate 422 and right foot plates 424 are shown as separated in FIG. 5, but as shown in FIG. 4A and FIG. 4B, are typically adjacent.

As shown in the figure, the Y distance between the user's foot position 506 on the left foot plate 422 and the force sensors F1L 502 and F4L 508 is Y1L, while the Y distance between the user's foot position 506 and the force sensors F2L 504 and F3L 510 is Y2L. The X distance between the user's foot position 506 on the left foot plate 422 and the force sensors F1L 502 and F2L 504 is X1L, while the X distance between the user's foot position 506 and the force sensors F3L 510 and F4L 508 is Y2L.

Similarly, the Y distance between the user's foot position 516 on the right foot plate 424 and the force sensors F1R 512 and F4R 518 is Y1R, while the Y distance between the user's foot position 516 and the force sensors F2R 514 and F3R 520 is Y2R. The X distance between the user's foot position 506 on the right foot plate 424 and the force sensors F1R 512 and F2R 514 is X1R, while the X distance between the user's foot position 506 and the force sensors F3R 520 and F4R 518 is Y2R.

The force applied to the left foot plate 422 by the user is FLTOT=F1L+F2L+F3L+F4L while the force applied to the right foot plate 424 by the user is FRTOT=F1R+F2R+F3R+F4R. If the user is standing on the platform 412 without holding the bar 416 or one or both of the handles 114 and is not carrying any other object, the weight of the user will then be FTOT=FL+FR.

Ideally the ratio between the output of the upper sensors in FIG. 5 and the lower sensors is the same for both sides, or (F1L+F2L)/(F4L+F3L)=(F1R+F2R)/(F4R+F3R), indicating that a line between the person's feet is parallel to the front and rear of the platform. Also, ideally, (F1L+F2L)=(F4L+F3L) and (F1R+F2R)=(F4R+F3R), indicating that both feet are centered in a front-back direction on the platform 412 (up-down down in FIG. 5). Finally, ideally (F1L+F4L)/(F2L+F3L)=(F3R+F2R)/(F4R+F1R), indicating that the user's feet are positioned symmetrically about the central line between the two foot plates 422, 424, noting the mirror image nature of the desired foot positions in this case.

The ratio between the output of the upper sensors in FIG. 5 and the lower sensors can be used to provide user feedback on foot positioning, if the ideal situation discussed above is not present. For example, if X2L/X1L=(F1L+F2L)/(F4L+F3L) is greater than X2R/X1R=(F1R+F2R)/(F4R+F3R), and the user's feet are facing upward in FIG. 5, then the user's left foot is further forward than their right foot, and the user can be prompted to either move their left foot back or their right foot forward until they are in a straight line. The foot that is furthest from the center of the foot plate, as determined by the greater deviation of X2L/X1L or X2R/X1R from a value of 1, will typically be the subject of the prompt to move it backward or forward.

Further, if both X2L/X1L and X2R/X1R deviate from 1 by more than a threshold amount, then the user is standing forward or backward from the center of the board too far. For values greater than 1, the user is standing forward on the board, while for values less than one, the user is standing back on the board. In such a case, the user will be prompted to move in the direction (backward or forward) that will tend to bring the X2L/X1L and X2R/X1R ratios back towards a value of 1.

Similarly, for placement of the feet along the Y direction, if Y2L/Y1L=(F1l+F4L)/(F2L+F3L) is less than Y1R/Y2R=(F3R+F2R)/(F4R+F1R), then the user is standing right of the center line of the platform 412, and can be prompted to move right, and vice versa. Other than this comparison, the actual values of Y2L/Y1L and Y1R/Y2R are not important, since these will depend on an individual's stance width. This determination assumes that the user is not manipulating the bar 416 or the handles 114 at all, or is doing so symmetrically. Preferably the left/right determination of the position is done under the former conditions.

The equations described above with reference to FIG. 5 are ratios, which makes them independent of different forces on the left and right force plates, either created intentionally by the user leaning more to one side or pulling harder on the one side, or due to differences in their muscle-skeletal structure. It is however also possible to determine the actual foot positions, as follows.

The total X distance between the left and right force sensors on left foot plate 422, and on the right foot plate 424, is known, and is XTOT=X1L+X2L=X1R+X2R. The total Y distance between the upper and lower force sensors on left foot plate 422, and on the right foot plate 424, is known, and is YTOT=Y1L+Y2L=Y1R+Y2R.

The ratio X2L/XTOT can be determined from the output of the sensors on the left foot plate 422 as (F1L+F2L)/(FLTOT), noting that a larger output from F1L 502 and F2L 504 implies a larger distance X2L and a smaller distance X1L. X2L can be determined by multiplying the determined (measured) ratio as follows: X2L=XTOT*(X2L/XTOT), and then X1L=XTOT−X2L, or X1L can be determined as above for X2L.

The ratio Y2R/YTOT can similarly be determined from the output of the sensors on the left foot plate 422 from (F1L+F4L)/FTOT). Y2L can be determined by multiplying the determined (measured) ratio as follows: Y2L=YTOT*(Y2L/YTOT), and then Y1L=YTOT−YL2, or X2L can be determined as for X1L.

Foot location is important for proper form and the balanced application of forces on the body. When users exercise with a barbell, proper foot location relative to the barbell is important. For example, if a user stands too far back from the line of the barbell, that can load the muscles of the spine too much. Usually, the information about foot location along with right posture is learned from exercise experts or monitored by an in-person coach while a user is doing the exercise. But when a user is exercising on their own without an expert witness to monitor their form, it can be difficult for the novice user to do it right.

By estimating a user's foot location, the exercise device 102/402 can sense how far away from an ideal foot position each foot is located. If one or both of the user's feet are too far away from the ideal location or ideal relative position from each other, as determined by a threshold from an ideal actual or relative position, this determination can be used by the embedded processor 2012 to disable the forces applied by the retraction mechanisms 1206. This requires the user to stand at the correct foot locations prior to being able to commence the exercise, and is a much more effective measure to ensure adherence compared to instructions or markings on the platform, which may get ignored. Additionally, during exercise, if the user moves a foot away from an ideal position by more than a certain threshold, the embedded processor 2012 disables the forces applied by the retraction mechanisms 1206. This can provide a way of disabling the forces if the user is struggling with a certain exercise, or otherwise wants to terminate or pause the exercise.

FIG. 6 is a schematic plan view of an exercise device 600, according to some examples. As shown in the figure, the exercise device 600 includes a platform 606 with a left cable exit 608 and a right cable exit 610. The exercise device 600 corresponds to the exercise device 102/402, but also includes a left LED strip 602 and a right LED strip 604, which are located for example one on each of the two side pods 108 or 408. By also including a strip of LEDs on the left and right side pod, the embedded processor 2012 can provide visual feedback about location of each foot and instructions to move the foot forward or backwards. The LED strips can be multi colored, including for example with red, yellow, green settings that can create different colors to indicate different directions or conditions.

The left and right LED strips 604, 602 can also be used to indicate direction by illuminating the LEDs in each strip such that they appear to run from back to front or front to back, in sequence at certain speeds to prompt the user to move one or both feet in the direction of apparent motion illustrated by the relevant LED strip. Such a visual indicator will be lot more effective and entertaining compared to markings on the platform. For example, if a person is standing too far back while doing a deadlift exercise, the LEDs could be orange and be illuminating from back to front to advise the user to move forwards while the force stays disabled or very low. As the user moves forward to the right location, the LEDs can stop blinking and turn green, while the full force selected becomes enabled for a lift/exercise.

Additionally, prompts can also be generated and provided audibly and/or visibly using the speakers 2316 and/or the display device 2202.

One advantage of the exercise devices 102, 402 is that the exercise forces can rapidly be turned on and off as needed. For example, a height setting can be provided where the exercise force stays off until the bar 416 or handle 114 reaches an appropriate height setting, and is turned on when the bar is raised higher than the height setting. This provides a so-called “virtual rack,” as it eliminates the need for a real rack to hold a barbell at a certain height from which the exercise can be commenced.

However, for an exercise like a back squat, just setting the minimum height at which the force is enabled is not enough, since the user needs to be able to pick up the bar from the ground, load it behind their head and then find a way to turn the force on so they can lower the bar from that height to do squats. Enabling the forces above a certain height would not work for this exercise, which depends on the user lowering the bar from the start height. When the user has finished, they again have to find way to turn the force off with the bar behind their neck. Usually, a real squat rack holds the bar at shoulder height, the user ducks their head under the bar and picks the bar on their shoulders from the squat rack. The user then replaces the bar back onto the squat rack when they are done. In a floor-based exercise platform with no real physical rack, there is need for a method of enabling and disabling the exercise force.

The foot location sensing can affirmatively be used by the user as a manual switch to accomplish this task. The user can stand with their sufficiently far feet back from the center line 612 of the platform 606, which will keep the force disabled, so it should be very easy to pick up the light bar 416 with very little tension on the cables 418, move it above their head and load it at the upper back region in preparation for the back squat. When ready, the user can walk forward a bit to locate their foot right under the bar line, which turns the LED strips green and enables the force. A short delay may be provided between reaching the correct position and enabling the force. The user can then perform squats. When the user is are ready to stop, they can move one leg back from the symmetrically-centered position or walk back a little bit, which should quickly disable the force and make it easy to pick the bar up off the back and move it above their head to them set it down on the platform.

This method is much easier to learn and trust for a user and costs nothing extra, compared to other solutions, such as a remote controller button on the bar that will have to wirelessly communicate over Bluetooth or similar technology to the platform to enable and disable force.

FIG. 7 is a plan view of an exercise device 700, according to some examples. As shown in the figure, the exercise device 700 includes a platform 702 with a left cable exit 710 and a right cable exit 708. The exercise device 700 differs from the exercise device 402 described above in that a single platform 702 is provided instead of a separate left foot plate 422 and right foot plate 424. Additionally, six load sensors are provided under the platform 702 instead of the eight load sensors provided under the foot plates of exercise device 402.

The exercise device 700 otherwise corresponds to the exercise device 102/402, but also includes a left LED indicators 704 and a right LED indicators 706, which are located for example one on each of the two side pods 108 or 408, or inward thereof. As before, the embedded processor 2012 can provide visual feedback about the location of each foot and instructions to move the foot forward or backwards using the left LED indicators 704 and right LED indicators 706. The LED indicators can be multi colored, including for example with red, yellow, green settings that can create different colors to indicate different directions or conditions. The LED indicators are described in more detail below with reference to FIG. 10 Additionally, prompts can also be generated and provided audibly and/or visibly using the speakers 2316 and/or the display device 2202.

The left cable exit 710 and right cable exit 708 can also be seen to be positioned ahead (above in the figure) of center line 712 in this example, since manipulation of the handles 114 or bar 116 will primarily occur ahead of the center line 712. As shown, in some examples, the platform 702 includes six force sensors 714, 716, 718, 720, 722 and 724. An example of the configuration and mounting of the force sensors is illustrated in FIG. 11.

FIG. 8 is a schematic diagram illustrating a top view of the location of a foot on the platform 702, and the relationship between the forces applied to the platform 702. In some examples, the platform 702 includes six force sensors, identified as F1L 714, F2M 716, F3R 718, F4L 720 F5M 722 and F6R 724 in FIG. 8. Since FIG. 8 is a top view, an “upper” force sensor in FIG. 8 corresponds to a front or rear sensor of the platform 702, with a “lower” force sensor in FIG. 8 then corresponding to a rear or front sensor of the platform 702.

As shown in the figure, the Y distance between the user's left foot position 802 and the force sensors F1L 714 and F4L 720 is Y1L, while the Y distance between the user's left foot position 802 and the force sensors F2M 716 and F5M 722 is Y2L. The X distance between the user's left foot position 802 and the force sensors F1L 714 and F2M 716 is X1L, while the X distance between the user's left foot position 802 and the force sensors F5M 722 and F4L 720 is Y2L.

Similarly, the Y distance between the user's right foot position 804 on the platform 702 and the force sensors F2M 716 and F3R 718 is Y1R, while the Y distance between the user's right foot position 804 and the force sensors F5M 722 and F6R 724 is Y2R. The X distance between the user's right foot position 804 and the force sensors F2M 716 d F3R 718 is X1R, while the X distance between the user's right foot position 804 and the force sensors F5M 722 and F6R 724 is Y2R.

The force applied to the left foot plate 422 by the user is FLTOT=F1L+F2M+F3R+F4L+F5M+F6R, which is the weight of the user if the user is standing on the platform 412 without holding the bar 416 or one or both of the handles 114 and is not carrying any other object.

Ideally the ratio between the output of the upper sensors in FIG. 8 and the lower sensors is the same for both sides, or (F1L+F2M)/(F4L+F5M)=(F2M+F3R)/(F5M+F6R), indicating that a line between the person's feet is parallel to the front and rear of the platform. Also, ideally, (F1L+F2M)=(F4L+F5M) and (F2M+F3R)=(F5M+F6R), indicating that both feet are centered in a front-back direction on the platform 412 (up-down down in FIG. 8). Finally, ideally (F1L+F4L)=(F3R+F6R), indicating that the user's feet are positioned symmetrically about a center line 806 of the platform 702.

The ratio between the output of the upper sensors in FIG. 8 and the lower sensors can be used to provide user feedback on foot positioning, if the ideal situation discussed above is not present. For example, if X2L/X1L=(F1L+F2M)/(F4L+F5M) is greater than X2R/X1R=(F3R+F2M)/(F6R+F5M), and the user's feet are facing upward in FIG. 8, then the user's left foot is further forward than their right foot, and the user can be prompted to either move their left foot back or their right foot forward until they are in a straight line. The foot that is furthest from the center of the foot plate, as determined by the greater deviation of X2L/X1L or X2R/X1R from a value of 1, will typically be the subject of the prompt to move it backward or forward.

Further, if both X2L/X1L and X2R/X1R deviate from a value of 1 by more than a threshold amount, then the user is standing forward or backward from the center of the board too far. For values greater than 1, the user is standing forward on the board, while for values less than one, the user is standing back on the board. In such a case, the user will be prompted to move in the direction (backward or forward) that will tend to bring the X2L/X1L and X2R/X1R ratios back towards a value of 1.

Similarly, for placement of the feet along the Y direction, if Y2L/Y1L=(F1l+F4L)/(F2M+F5M) is less than Y1R/Y2R=(F3R+F6R)/(F2M+F5M), then the user is standing right of the center line of the platform 412 (as illustrated in FIG. 8), and can be prompted to move right, and vice versa. Other than this comparison, the actual values of Y2L/Y1L and Y1R/Y2R are not important, since these will depend on an individual's stance width. This determination assumes that the user is not manipulating the bar 416 or the handles 114 at all, or is doing so symmetrically. Preferably the left/right determination of the position is done under the former conditions.

The equations described above with reference to FIG. 8 are ratios, which makes them independent of different forces on the left and right force plates, either created intentionally by the user leaning more to one side or pulling harder on the one side, or due to differences in their muscle-skeletal structure. It is however also possible to estimate the actual foot positions, as follows.

If XTOT=X1L+X2L=X1R+X2R and is YTOT=Y1L+Y2L=Y1R+Y2R, then the ratio X2L/XTOT can be determined from the output of the sensors on the platform as (F1L+F2M)/(F1L+F2M+F4L+F5M), noting that a larger output from F1L 714 and F2M 716 implies a larger distance X2L and a smaller distance X1L. X2L can be determined by multiplying the determined (measured) ratio as follows: X2L=XTOT*(X2L/XTOT), and then X1L=XTOT−X2L, or X1L can be determined as above for X2L. The same determination can be for X1R and X2R, using F3R and F6R instead of F1L and F4L.

The ratio Y2R/YTOT can similarly be determined from the output of the sensors on the platform 702 from (F1L+F4L)/(F1L+F2M+F4L+F5M). Y2L can be determined by multiplying the determined (measured) ratio as follows: Y2L=YTOT*(Y2L/YTOT), and then Y1L=YTOT−YL2, or X2L can be determined as for X1L. The same determination can be for X1R and X2R, using F3R and F6R instead of F1L and F4L.

It will be appreciated that the number of force sensors provided or used on the platform for the determination of a user's foot position can vary. In some examples, a total of four sensors can be used, such as F1L 714, F4L 720 and F3R 718, F6R 724, which would approximate F1L/F4L=X1L/X2L and F3R/F6R=X1R/X2R. This would also approximate Y2R/Y1L=(F1L+F4L)/(F3R+F6R) for sufficient relative foot positioning along the Y axis. In such a case, force sensors F2M 716 and F5M 722 could be omitted for cost reduction and replaced with fixed mounting points or no mounting points at all, the latter requiring a stiffer or less wide platform 702. Alternatively, six sensors can be provided but only F1L 714, F4L 720 and F3R 718, F6R 724 used for positioning as discussed in this paragraph, with F2M 716 and F5M 722 only used for determining total weight.

Finally, unless the context indicates otherwise, the term force sensor as used herein can refer to any sensor for detecting the presence of a foot on the platform, whether or not the force sensor in fact provides an output of the magnitude of the force. In some examples, a multi-touch capacitive touch screen is provided on all or part of the platform 702. In other examples, an array of capacitive touch sensors could be provided over the surface of the platform 702. In such a case, application of force to the upper surface of the panel will result in detection of both the presence and the location of a user's foot, which can then be used to provide prompts to the user as discussed herein.

FIG. 9 is a plan view of the platform 702 of the exercise device of FIG. 7, according to some examples, illustrating foot positioning thresholds. Due to hysteresis of the load cells and possible inaccuracies, and the fact that a person's foot has a non-trivial length, and that users may distribute their weight differently front-to-back on the soles of their feet, the exact position of the (center) of a user's foot cannot be determined accurately. Accordingly, a threshold tolerance of approximately 3 in. total (or 1.5 in. forward or backward of the centerline is appropriate in some examples.

Accordingly, a front threshold 902 and a rear threshold 904 are specified for the exercise device 102, 402, 700. As long as the user's feet are each between the front threshold 902 and the rear threshold 904 as determined by the exercise device or an associated device, no warning or instructions are provided to the user to adjust their feet. However, if the exercise device 102, exercise device 402, exercise device 700 determines that one or both of the user's feet are ahead of the front threshold 902 and/or behind the rear threshold 904, then a notification is provided to the user to move the relevant foot or both feet as the case may be. Additional steps may be taken based on detection by the exercise device that one or both of the user's feet are ahead of the front threshold 902 and/or behind the rear threshold 904, including not applying the full force of an exercise to the cables 202 until the user's feet are correctly positioned, or removing the full force of an exercise if a user's foot is moved beyond one of the thresholds 902, 904.

It will be appreciated that the center line 712 need not in fact be located at the actual center of the platform 702 of the exercise device 102 in the front and back direction, but is the effective center line for purposes of the exercise, on which it is intended that the user stand. The position of the center line 712 may be forward or backward of the actual center line of the platform 702 depending on the configuration of the board, characteristics of the user, and so forth. Similarly, the position of the cable exits 708 on the board as well as their relationship to the effective centerline may vary. In some examples, the effective center line may be moved forward of the physical center line to match with a line joining the cable exits 708. In some examples, the location of the cable exits 708 be moved backwards to coincide with the physical centerline of the platform.

The effective center line 712 can also be moved forward or backwards in the associated software, such as in an app or in the embedded processor 2012, by adjusting the ratios between the measured forces used to define the location of the center line 712. Similarly, the distance of the front threshold 902 and rear threshold 904 from the center line 712 can also be varied by varying the parameters in software.

FIG. 10 is a plan view of the right side of the platform 702 of FIG. 7, according to some examples, to illustrate the right LED indicators 706. The right LED indicators 706 are seen to include a “move foot back” chevron 1002, a “move foot forward” chevron 1004 and a status indicator 1006. If the exercise device 102/402/700 determines that the user's right foot (or both feet) are ahead of the front threshold 902 or behind the rear threshold 904, the relevant one or both of the “move foot back” chevron 1002 or “move foot forward” chevron 1004 is/are illuminated to prompt the user to move their right foot (or both feet) in the direction indicated by the relevant chevron. The chevrons 1002, 1004 can be illuminated in various colors, can flash, or the bars in the chevron can be illuminated in sequence to emphasize the instructed direction of movement. As mentioned previously, the visual indications provided by the chevrons 1002, 1004 can be associated with enabling or disabling the force applied by the cables.

The status indicator 1006 can be illuminated to provide relevant status information, such as illuminating green when the user's right foot is positioned correctly, or when both feet are positioned correctly. In some examples, the status indicator 1006 can flash to provide notification of the imminent application of the full exercise force to prepare the user to begin exercising.

Numerous display variations are possible. In some examples, the whole platform 702 or part thereof may be constructed as a multi color or single color display panel with a scratch resistant transparent top. In such a case, a recommended foot position can be displayed as an outline, the current status of the user's foot position, and movement recommendations may be provided. Additional information, such as the user's total weight, weight history, and so forth can then also be provided. Such a display may also include capacitive touch sensing to determine foot position as described above.

In some examples, LED strips are embedded in the platform 702 with a transparent cover as needed, along the center line 712, front threshold 902 and rear threshold 904. Alternative lighting techniques can be used in all cases, for example light pipes, illuminated by light sources in one or both of the side pods 108 could be provided along the center line 712, front threshold 902 and rear threshold 904. A light source such as a laser in a side pod 108 can be used to create a beam that diverges beam along a vertical plane to interact with a reflective bottom surface or reflective strips or features (such as reflective angled cutouts) in a light pipe, thereby to direct light upwards towards the top surface of the platform 702.

FIG. 11 is an exploded perspective view of the configuration and mounting of one of the force sensors 714, 716, 718, 720, 722 and 724 of FIG. 7 and FIG. 8, according to some examples. As illustrated, the force sensor comprises a load cell 1102 mounted to a base 1104 via a spacer 1106. The load cell 1102, the spacer 1106 and the base 1104 are fastened together using several bolts 1112. In some examples, the load cell 1102 is a planar beam load cell, and the base 1104 is an internal frame of the exercise device 700 to which other components are mounted.

The platform 702 is in turn mounted to the load cell 1102 via a spacer 1108 and a bolt 1110. The head of the bolt 1110 may be recessed into the platform 702, and the spacer may be made of a hard rubber or other material that will permit some accommodation of deflection or flexing of the platform 702 during use.

FIG. 12 illustrates the arrangement of components inside the exercise device 102 to provide cable tension and management according to some examples. FIG. 12. is a schematic top view of the exercise device 102 showing the position of a retraction mechanism 1206 in a left side pod 1202 and a cable guide 1208 in the right side pod 1204. For purposes of clarity, the components are only described with reference to the cable 202 that exits the right side pod 1204. It will be appreciated that the arrangement of the illustrated components is mirrored for the cable that exits the left side pod 1202, but with the retraction mechanism in the right side pod 1204 facing in the opposite direction so that the cables crisscross underneath the platform with a small clearance between the cables and an underside of the platform. This configuration of retraction mechanisms 1206 and cable guides in opposite side pods with the cables passing in opposite directions allows a low platform height, which just needs to be sufficiently high to allow adequate cable clearance.

An example of the cable guide 1208 is described in more detail below with reference to FIG. 15, FIG. 16, and FIG. 17, while an example of the retraction mechanisms 1206 is described in more detail below with reference to FIG. 18.

The retraction mechanism 1206 includes an electric motor 1212 and a directly coupled long tubular threaded spool 1210 onto which the cable 202 winds and unwinds in use of the exercise device 102, under torque that is applied to the threaded spool 1210 by the motor 1212. The cable 202 passes through the chassis 104 under the platform 106 from the threaded spool 1210 to the cable guide 1208. The spool is a zero-backlash mechanism to convert torque to tension, which may sometimes be powered manually or by an electric motor. An electric motor can also be called an electro-magnetic mechanism that uses electricity and magnetism to create torque.

The cable guide 1208 in turn comprises a pulley 1216 that receives the cable 202 from the retraction mechanism 1206 and guides it upwards so that it is oriented generally vertically and can be attached via its attachment point 112 (not shown) to a handle 114 or the bar 116. Also provided are two rollers 1214 that permit movement of the cable in a forward or backward direction (up or down in FIG. 12) relative to the platform 106.

FIG. 13 is an underside view of the platform 702, according to some examples. As can be seen, to provide stiffness to the platform without unduly increasing its weight, a number of beams 1302 are provided between the load cells 1102. Furthermore, several ribs 1304 are provided, extending front to back on the platform 702 between the beams 1302. The ribs 1304 and beams 1302 may be made of various materials such as plastic or aluminum. Various configurations of supporting and stiffening structures are contemplated or possible, such as use of a formed sheet, for example including corrugations, in place of the ribs 1304.

FIG. 14 is a flowchart 1400 illustrating a method of operating the exercise device 102 according to some examples. For explanatory purposes, the operations of the flowchart 1400 are described herein as occurring in serial, or linearly. However, multiple operations of the flowchart 1400 may occur in parallel. In addition, the operations of the flowchart 1400 need not be performed in the order shown and/or one or more blocks of the flowchart 1400 need not be performed and/or can be replaced by other operations. The operations of the flowchart 1400 may be controlled or performed by the embedded processor 2012 in the exercise device 102 (see FIG. 20), and/or by code running on one of the other devices in system 2300 (see FIG. 23), such as one of the client devices 2304, the set top box 2308, the server 2302 and so forth. In some cases the devices may work together to perform the method. For example, an interactive exercise program running on the server 2302, a client device 2304 or the set top box 2308 may receive inputs, such as user input to start an exercise session, or an indication of the presence or position of a user on the exercise device 102 from the exercise device 102, which may then provide an instruction to the embedded processor 2012. For the purposes of illustration only, the flowchart 1400 is described herein as being performed by the exercise device 102 using the embedded processor 2012.

The method starts at operation 1402 with the exercise device 102 being powered on. After the exercise device 102 is in a state in which it is ready for the user to begin exercising in operation 1404, the method proceeds to operation 1406. The exercise device 102 may for example need to perform various checks, make certain connections, receive appropriate instructions from for example an associated exercise app, and check other contextual factors before being ready for exercise.

The exercise device 102 measures the forces exerted by the user on the platform in operation 1406 using force sensors as described in more detail above. Using the measurements and the identities of the force sensors, the exercise device 102 determines the placement of the user's feet as described in more detail above, in operation 1408. The exercise device may also include a minimum threshold total weight, for example 50 lbs., below which the exercise device 102 will not be enabled.

In operation 1410, the exercise device 102 compares the position of the user's feet to determine if both feet are positioned correctly with respect to the specified thresholds. As mentioned above this can be the fore/aft positions of both feet, left/right positioning of each foot relative to a centerline, and/or relative positioning of the feet with respect to each other.

If the feet are positioned correctly as determined in operation 1410, the exercise device 102 is enabled in operation 1412 and the user can begin exercising. This will typically involve enabling the retraction mechanisms 1206 to apply the specified force to the cables 202 and thus the handles 114 or the bar 116.

If the feet are not positioned correctly as determined in operation 1410, a notification is provided to move each or both of the feet in a direction towards correct placement as appropriate in operation 1414. In some examples, this is done using LED indicators on the exercise device 102 as described above, but other notifications could also be provided, for example text or graphics on display device 2202 or television 2318, or audibly via earbuds 2314 or speakers 2316.

In both cases, the flowchart 1400 then returns to operation 1406 and proceeds from there with continued monitoring of the forces applied to the platform by the user.

In addition to providing safer operation of the exercise device 102, this also permits a user to position the bar 116 or the handles 114 at a desired exercise height before commencing the exercise, as well as terminating the exercise by stepping slightly forward or backward with one foot, irrespective of the height of the bar 116 or handles 114.

FIG. 15 is a perspective view of the cable guide 1208 of FIG. 12 according to some examples. The cable guide 1208 includes a housing 1502 within which the two rollers 1214 are rotationally mounted with the cable 202 exiting the housing 1502 between the rollers 1214. Below the housing, the pulley 1216 receives the cable from the direction of the retraction mechanism 1206 and turns it upward towards the attachment point 112 (not shown) where it can be attached to a bar 116 or a handle 114. The rollers 1214 and the pulleys 1216 are mounted to the housing using sealed ball bearings to provide quiet and low-friction movement of the cable 202. The elongated rollers 1214 are parallel to each other and oriented in a direction across the exercise device 102 with a gap between them through which the cable passes. The pulley 1216 is located underneath the gap between the rollers 1214.

FIG. 16 is a front view of the cable guide 1208 of FIG. 12 according to some examples. As can be seen, the arrangement of the rollers 1214 and the pulley 1216 permit functional side-to-side movement of the cable 202 between an outer limit 1602 and an inner limit 1604 within which the movement of the cable 202 does not interfere with the housing 1502. The pulley 1216 is positioned such that the vertical exit point of the cable 202 from the housing is offset to towards the outside of the exercise device 102 (away from the platform 106) so that the angle between vertical and the inner limit 1604 is greater than the angle between vertical and the outer limit 1602, since in use the handles 114 are likely to extend further over the platform 106 than away therefrom.

FIG. 17 is a side perspective view of the cable guide 1208 of FIG. 12 according to some examples. The arrangement of the pulley 1216 below the gap between the roller 1214 can clearly be seen in FIG. 17. Also, it can be seen that the rollers 1214 permit the cable 202 to move functionally forward and backward over the exercise device 102 without it interfering with the housing. The arrangement of the rollers 1214 and the pulley 1216 ensure that the cable 202 can be moved not only in a vertical direction but also within a certain range of angles from the vertical in all four directions (left, right, forward, and backward).

FIG. 18 is a top view of the retraction mechanism 1206 of FIG. 12 according to some examples. In use, the retractable cables wind and unwind on a long tubular threaded spool 1210, which is coupled directly to the shaft of the motor 1212, which is a brushless AC electric motor in some examples. The threaded spool 1210 converts the torque and rotation of the motor 1212 into tension and linear movement of the cable 202 in use.

A helical groove 1802 on the threaded spool 1210 is sized to receive the cable 202 and ensures that the cable 202 winds smoothly onto and off the threaded spool 1210 without overlap. The cable 202 is secured at the far end 1804 of the threaded spool 1210 in some examples. The width of the groove 1802 matches the nominal thickness of the cable 202. The helical groove in the spool can be clockwise or anti-clockwise along the length looking from the direction of the motor, depending on the desired direction of rotation of the threaded spool 1210. When fully retracted, approximately 9 feet of cable 202 is wound on the threaded spool 1210 to provide enough cable length for a user with a height of 6 feet 6 inches and proportionally long arms to hold a bar 116 fully extended vertically above their head as shown in FIG. 3C.

To provide rapid responsiveness and natural feel under cable acceleration (for example when initiating a movement or during a directional change during a movement, it is desirable that the motor and the threaded spool 1210 have relatively low rotational inertia. Furthermore, additional rotating components such as gears or pulleys or belts or chains, especially with substantial mass and a large outer diameter, will add to the net rotational inertia of a rotating mechanism. Gearboxes additionally have backlash (also known as play or slop), which refers to the angle that the output shaft of a gearhead can rotate without the input shaft moving. Backlash can create noise and reduce responsiveness. The use of a direct drive motor without any gears, pulleys or sprockets or belts or chains between the motor 1212 and the threaded spool 1210 provides a low moment of inertia without backlash between the motor 1212 and the threaded spool 1210. In some examples, the groove 1802 may be fabricated directly into an extended shaft that protrudes from the motor 1212.

The retraction mechanism 1206 needs to create a relatively high force, for example up to 150 lbs on each cable 202, for a total maximum force of 300 lbs on the bar 116 in barbell mode. The maximum torque required can be determined by multiplying the required force by the radial distance from the center axis of the threaded spool 1210 to the center of the cable 202 on the threaded spool 1210. To create the required relatively high force, either the peak torque capacity of the motor 1212 needs to be relatively high or the radius of spool needs to be relatively low. As the torque increases, motors become bigger, heavier and more expensive. To keep the cost and the weight of the exercise device 102 down, a light weight and low-torque motor is desirable, which requires that the radius of the threaded spool 1210 be kept quite small, allowing relatively high force generation using a relatively small and low-torque motor.

As the radius of a conventional spool becomes smaller, problems can arise with the number of turns required to accommodate a long cable. This can result in the cable overlapping itself or require the provision of special winding mechanisms. To resolve these challenges, the threaded spool 1210 is designed to an elongated rod or tube, with the length of the threaded spool 1210 being defined by the length of cable wrapped in the helical groove of the spool. In some examples the length of the groove is a multiple (integer or non-integer) of at least twice its diameter.

With a spool having a thread to accommodate the cable, such as the threaded spool 1210, the spool can become quite long to accommodate the approximately 9 feet of cable. A long spool can cause problems as the span between the cable being fully wound and fully unwound on the spool can become significant. There is also a certain limit to how wide (front to back) the exercise device 102 can be while still retaining a desirable form factor. Additionally, the platform 106 is quite low for user convenience, and does not itself provide sufficient room for a retractor mechanism. The dimensions of the threaded spool 1210 will thus depend on a number of factors, including the width (front to back) of the exercise device 102, the desired size of the side pods 108, the bending forces that the threaded spool 1210 will need to endure when the cable is under maximum design load at the far end 1804 of the threaded spool 1210, motor size, torque and speed requirements, and so forth.

In one example, with a maximum motor torque of 7 Nm, a cable length to unspool of 9 feet and a spool pitch of 4 mm, the required 150 lb. force can be generated with a spool having a diameter of 21 mm, with a helix length of 167 mm and an overall spool length of 219 mm to accommodate the cable length. In this case the spool length is thus approximately ten times the spool diameter, although it will be appreciated that other integer or non-integer multiples are possible. Preferably the spool length is at least five times the spool diameter, but no less than twice the spool diameter.

FIG. 19 is a perspective view of a retraction mechanism 1206 according to some further examples. As before, the retractable cables wind and unwind on a long tubular threaded spool 1210, which is coupled directly to the shaft of the motor 1212, which is a brushless AC electric motor in some examples. The threaded spool 1210 converts the torque and rotation of the motor 1212 into tension and linear movement of the cable 202 in use. The motor 1212 is mounted to a frame 1902, which is in turn mounted to a chassis of the exercise device 102/402. The end of the threaded spool 1210 remote from the motor 1212 is coupled to the frame 1902 by a bearing mounted in a bearing bracket 1908. This bearing reduces or eliminates bending forces on the threaded spool 1210 and shaft, which would otherwise have to be absorbed by the motor 1212

The retraction mechanism 1206 includes a locking safety mechanism 1906 that prevents withdrawal of a cable from the side pods 108/408 unless the exercise device is powered on and enabled. The safety mechanism 1906 is located outboard of the bearing bracket 1908, and enablement of the device is typically done by an adult through the set top box 2308 via the television remote control 2312 (see FIG. 23) or an application on the client device 2304 when the user wants to exercise, in conjunction with other contextual factors. The safety mechanism 1906 remains or enters a default locked position when not affirmatively activated or in the case of power loss to the exercise device 102/402 or to the retraction mechanism 1206, by engaging a ratchet wheel or gear 1904 mounted to the shaft of the motor 1212.

FIG. 20 illustrates an electrical control system 2002 and related components for the exercise device 102 according to some examples. Illustrated in FIG. 20 are a left motor 2004 with a left encoder 2006 and left motor terminals 2014, a right motor 2008 with a right encoder 2010 and right motor terminals 2016, an embedded processor (microcontroller) 2012, a rechargeable battery pack 2020 with a battery management system 2018, and a left motor hex bridge inverter 2026 and a right motor hex bridge inverters 2024. The battery terminals 2022 are coupled to the hex bridge inverter 2024 and hex bridge inverter 2026, which are in turn coupled to the left motor terminals 2014 and right motor terminals 2016 respectively. The hex bridge inverter 2026 and hex bridge inverter 2024 are each independently controlled by the embedded processor 2012 to provide a current through each motor that will generate a required torque in the left motor 2004 and right motor 2008 respectively.

The control system 2002 for an AC motor is often called as an inverter as it takes DC voltage and coverts it into three phase AC voltage that then drives the AC motor. The control system 2002 comprises a dual inverter that can independently drive the left motor 2004 and right motor 2008. The embedded processor 2012 manages the exercise device 102 using seven sensors 2030 for current and voltage (one on each winding of each motor and one on the DC input bus current), a left encoder 2006 for the left motor 2004 and a right encoder 2010 for the right motor 2008. The embedded processor 2012 sends pulse-width modulation signal commands separately to the hex bridge inverter 2024 and hex bridge inverter 2026, each of which comprise 6 electronic MOSFET switches.

The DC inputs from the battery terminals 2022 to the hex bridge inverter 2026 and hex bridge inverter 2024 each include a DC link capacitor 2028 to reduce higher frequency voltage and current ripple. If the PWM frequency is less than 20 khz, audible motor noise may be created due to the creation of vibrations at frequencies that are audible to humans. Accordingly, the PWM frequency used by the embedded processor 2012 is greater than 20 kHz and can for example fall within a range of 30-60 khz. Higher PWM frequencies also create cleaner sinusoidal current waveforms with less torque ripple in low inductance motors, which can further reduce audible noise and improves motor efficiency. Motors that have quicker responses will often have very low inductance and are desirable in an application like this to provide quick responsiveness. The switching losses in the MOSFET switches increases with higher PWM frequencies, hence the gate drive circuit for each MOSFET is designed carefully in the PCB layout and configured to reduce gate ringing and switching losses in the MOSFETs

To provide a DC input power source, a battery pack 2020 is used instead of a DC power supply. In use, the exercise device 102 may draw high power from the battery pack 2020 for short periods of time during movement of the bar 116 or handles 114 in one direction, with a quick return to low power or no power when moving in the other direction. The power draw is usually higher while the cable 202 is being retracted, compared to when the cable 202 is being withdrawn. Each motor may act as generator while the user is lifting the bar 116 or a handle 114, thus consuming low power or even negative power. Negative power draw means that current tends to flow back from the motor to the inverter and the DC power source.

Standard DC power supplies that run off the electrical grid are normally unable to receive current or power in such situations as they are usually unidirectional by design. Hence, the excess power is diverted to power resistors to dissipate as heat. If the excess power is not diverted, the DC bus voltage in the DC link capacitors 2028 can rise to dangerous levels leading to permanent damage to the capacitors and/or the MOSFETs and/or the power supply. Bidirectional power supplies exist that return power to the electrical grid, but they are heavy and expensive.

Using a battery pack 2020 as the power source permits power to be returned to the battery pack 2020, which avoids the need for power resistors, keeps the exercise device 102 cooler and also proves to be energy efficient. Additionally, battery packs 2020 are good at providing high current levels for short periods of time due to their lower internal resistance. The size and cost of the battery is thus not defined by the peak power requirement but instead by the total energy consumed. Hence, using a battery pack 2020 instead of a DC power supply can make the exercise device 102 cheaper and lighter. The size and cost of a DC power supply is defined by the peak power requirement, which makes them heavier and expensive.

Additionally, use of the exercise device 102 is made more convenient and flexible by providing a battery pack 2020 instead of a DC power supply, which needs a thick power cord connected to the power outlet, that brings high voltage AC down to the device and corresponding safety concerns especially the risk of an electric shock in case of a fault. A long power cord or extension cord can also act as a trip hazard. A small low voltage DC output trickle charger can be used that slowly charges the battery pack 2020 over a period of time when the device is not in use. The relatively higher voltage from the power outlet just goes to the trickle charger and not the exercise device 102. The charger module can be a wall outlet mount module that may have already been certified. The battery management system 2018 keeps track of the voltages in the cells of the battery pack 2020 during charging and ensures that all cells are evenly charged. The battery management system 2018 systems keeps track of the battery voltage and disables the exercise device 102 if the battery is almost fully discharged, to protect the battery from permanent damage that may result from over discharging.

The left encoder 2006 and the right encoder 2010 are each multi-turn type encoders that keep track of rotational position changes beyond 360 degrees and they are thus able to provide an output that is proportional to length of unspooled cable 202 outwards on both sides of the exercise device 102. This permits measurement of the height of the bar 116 or handle 114 above the platform 106. When using a traditional barbell, for exercises like an overhead press, the user needs to first place the barbell on the studs of a squat rack at a certain height and has to load the weights onto the barbell before the exercise can be performed. This ensures the force start point is set at the certain height above the floor and the exercise is always performed at a height above this start point. The user can also easily return the barbell to the squat rack at end of the exercise or during the exercise if they are struggling, without risking injury. But it can still be risky or inconvenient, if the user lowers the bar below the height of the studs during the exercise

FIG. 21A is a graph that illustrates the relationship of the height of the bar 116 or handle 114 above the platform and the perceived weight experienced by the user, according to some examples. Since the position or height of the bar 116 or handle 114 above the platform 412 is known by the exercise device 102, a preset force-start start point 2102 at certain height above the platform can be set so that the tension in the cables 202 stays close to zero when the bar 116 or handle 114 is under the force-start start point 2102. This enables a user to pick up and lift the bar 116 or handles 114 easily and safely at a small nominal tension in the cables until the designated point at which the tension in the cable increases to the required level. The increase in the tension in the cables 202 to the required level occurs linearly over a short distance to avoid a sudden increase in the forces experienced by the user, until it reaches the full weight point 2104 of the exercise. If any time the user lowers the bar 116 or handles below the start point 2102, the tension in the cable returns to the small nominal tension, reducing or eliminating the risk of the user getting hurt if they are struggling to maintain the forces need to perform the exercise. This makes the exercise device 102 safer than a barbell picked up from studs on a squat rack.

The height of the force start point 2102 point can be specified for different exercises and for different users. It may be set to immediately above the shoulders for overhead-press as shown in FIG. 3C. For bicep curls, as shown in FIG. 3A, the force-start point height may be set aligned with mid thighs. For bent-over-rows, the force-start point height maybe set aligned with the knees. For deadlifts, it may be aligned to the lowest height that a user can comfortably lean based on their mobility and flexibility. This feature eliminates the requirement for a bulky squat rack while providing a safe exercise environment while doing workouts typically associated with free weights. The force-start point for every exercise along with the designated weight or force level can be stored for future use or entered before the exercise. In some cases, the user can enter their height and optionally their gender in an associated device such as a smartphone, the exercise device 102 or the associated device can calculate force-start points heights for various different exercises based on the user's height and known body proportions. The user can also directly specify start point heights or fine-tune start-point heights that have been estimated from the user's height, based on user preferences.

The left encoder 2006 and right encoders 2010 also permit the speed of each threaded spool 1210 to be monitored. If the user ever drops a bar 116 during an exercise, the bar 116 will accelerate under the effects of tension in the cables 202 force and gravity on the bar 116, with a corresponding rapid increase in the speed of the motors 1212. This is sensed by the encoders and in response to the embedded processor 2012 detecting that the speed of the cable or the speed of the motor 1212 has exceeded a certain threshold, the embedded processor 2012 triggers a safety feature to cut the current to the motors 1212 and thus releases the tension in the cables 202.

The height of the bar 116 or cable 202 can also be used to release the tension in the cable 202 if height thresholds are triggered before the speed of the motor 1212 has reached the speed threshold. For example, if a start-point height has been set, the tension in the cables will revert to the small nominal tension if the bar 116 or handle 114 goes below the start-point height. Furthermore, if the bar 116 or handle 114 is dropped from a low height above the platform 106, the tension in the cables will revert to the small nominal tension once a minimum height above the platform is reached as detected by an encoder. While the bar 116 or handle 114 will still continue to fall under the effect of gravity, the impact of the bar 116 or handle 114 when it lands will be much more benign compared to dropping a weighted barbell or dumbbell. Additionally, the bar 116 will hit the side pods 108 first before hitting the user's feet.

FIG. 21B is a graph that illustrates the perceived weight experienced by the user based on direction of motion of the cables 202, according to some examples, while FIG. 21C is a graph that illustrates the perceived weight experienced by the user based on the range of motion of the cables 202 during an exercise, according to some examples.

It has been observed that strength of a user during an exercise is not fixed throughout the range of motion or the direction of motion. For example, while doing a deadlift, the strength of a user increases as the weight moves up in the range of motion. And the strength of a user is typically higher while lowering a weight (called the eccentric phase) compared to when they are lifting the weight (called the concentric phase). Hence, it may be beneficial to challenge the user by varying the tension in the cables 202 at different points in the user's range of motion (called accommodating resistance) or based on the direction of motion (called eccentric overloading) to match their strength curve.

Based on the outputs from the encoders, the tension in the cable can be varied by the embedded processor 2012. As shown in FIG. 21B, based on the encoders reporting that the cable 202 is being withdrawn, a first (lower) force level can be specified and controlled by the embedded processor 2012 for the concentric phase force 2106. Similarly, based on the encoders reporting that the cable 202 is being retracted, a second (higher) force level can be specified and controlled by the embedded processor 2012 for the eccentric phase force 2108. The direction of movement of the cable 202 can also be determined by the embedded processor 2012 encoder output detecting whether the encoder output is increasing or decreasing.

As shown in FIG. 21C, the embedded processor 2012 can also specify and control the tension in the cables to increase the force on the bar 116 or a handle as a cable 202 is being withdrawn from the side pods 108. In the figure, the relationship 2110 is shown to be a linear relationship between the height above the platform 106 and the force experienced by the user, but it will be appreciated that other relationships could be specified as needed or to match the strength curve of a user over the range of motion for a specific exercise.

With a traditional barbell, the user has to overcome the inertia of the barbell to move it from zero speed to a certain speed, hence the amount of force exerted by the user at beginning of a lift may be perceptibly higher than the weight of the barbell. As the barbell slows down at the end of the lift, the amount of force exerted by the user may be perceptibly lower than the weight of the barbell. Similarly, while changing direction during a curl or other exercise, the amount of force exerted by the user will be higher than the weight of the barbell at the bottom of the motion and lower at the top of the motion. While lowering the weight, if the user lowers the weight rapidly, the perceived force will be lot lower than the gravitational weight. This is known as the inertia effect.

Users are often advised to lift weights slowly and lower them very slowly. This makes sure the amount of force exerted by the user stays uniform throughout the range of motion and during the concentric and eccentric phases. However, in some power lifting exercises such as snatch, clean and jerk, the momentum of the barbell is utilized to perform the exercise. These dynamic movements are for advanced users and can be hurtful if not done properly, due to sudden changes in amount of force exerted by the user.

Since the exercise device 102 is able to measure the speed of the motors 1212, the embedded processor 2012 can include a program or setting that increases or decreases the force in the cables dynamically as the speed of movement of the cable 202 increases or decreases. This feature allows the exercise device 102 to simulate the inertia effect. The amount and the rate at which the inertia effect is simulated can also be set or modified by the user.

If the inertia effect is not being simulated, an advantage of the exercise device 102 over free weights is that that no matter how fast a user lifts or lowers the bar 116, the amount of force experienced by the user can be controlled by the embedded processor 2012 to be uniform or to vary uniformly as discussed above. This ensures the amount of force experienced by the user does not change suddenly or unexpectedly, providing additional safety benefits.

It has also been observed that strength of a user may vary from day to day due to various circumstances. The strength of a user may also decrease over the course of a session. The exercise device 102 can capture metrics relating to the time of repetitions and/or the times or speeds of concentric and eccentric phases. Based on a certain change in the time or speed of one or more repetitions or phases from an average determined over the course of a session, or from previous sessions, the embedded processor 2012 can reduce the designated force profile for a particular exercise as the user's strength seems to drop, or increase the designated force profile for the exercise if the user's strength seems to have increased. This may reduce the need for the user to manually designate the level of a force profile at beginning of every exercise session, although it is always possible to set the level of resistance if desired. Such a features makes the process very time-efficient and frees the user from the burden of deciding how much to lift,

The platform 106 may also have a plurality (four in some examples) of electrode sensors and/or a dedicated retractable hand bar may include a plurality of electrode sensors in addition to or instead of sensors in the platform 106. These electrodes send very tiny amounts of current up through one leg and down through other leg, or through the user's hands in the hand-held sensors, to be able to estimate body composition (percentage of bone, muscle, subcutaneous and visceral fat) as well as to estimate the heart rate of the user. Such information about the body observed over time and alongside the exercise data can be used to track the progress and wellness of the user.

FIG. 22 illustrates a display that may be shown on a related display device 2202 during use of the exercise device 102, according to some examples. The display includes a window with a video feed 2204 from a camera located in or on the display device 2202 and pointed at the user, so that they can monitor their form during the exercise. Alternatively, an instructor or avatar can be shown instead, to provide guidance to the user. The display also includes a chart 2206 showing the height of the bar 116 over time, as well as a display of the force applied to the bar over time. The display also includes a status display 2208 that shows the selected exercise, the exercise mode (such as fixed force or height or speed adaptive), the number of sets of the exercise that have been done in the current session, and the number of repetitions done in the current set of the exercise.

FIG. 23 illustrates a system 2300 including an exercise device 102, a server 2302, and client devices 2304 according to some examples. In various examples, the client devices 2304 may include desktop PCs, mobile phones, laptops, tablets, wearable computers, smart televisions or other computing devices that are capable of connecting to the Internet 2306 and communicating with the server 2302, such as described herein. The client device 2304 may be paired with the exercise device 102 using a Bluetooth connection, to provide a user interface by means of which a user of the exercise device 102 can manage the exercise device 102, as well as to receive feedback on their use of the exercise device 102.

A mobile phone or a tablet computer may be a suitable client device 2304 for use with the exercise device 102, since these devices have a touch screen for display and user input, a Bluetooth adapter for communication with the exercise device 102, a Wi-Fi adapter for connection to the Internet 2306, and a camera and microphone for video communication. An application running on a mobile phone or tablet computer can thus do all the data processing, relaying of logged data to the server 2302, as well as streaming of video or other audio content from the internet, and communicating with the users of other exercise devices 102 or with remote personal trainers. Such an application can also be used to control the exercise device 102 to select exercise types and levels, select different user profiles for the exercise device 102, and track and display information about the user's current session and overall progress as shown in FIG. 22.

Another suitable device for use with the exercise device 102 is a set top box 2308 with an associated television 2318 or monitor. The set top box 2308 is a smart, internet-connected device with an inbuilt computer capable of running an application to provide the capabilities described above with reference to the client device 2304. Some examples of such a set-top box are Amazon Fire TV cube, Amazon fire TV stick, Google Chromecast TV, and so forth. The television 2318 may also be a smart television that has set top box functionality built in, in which case a separate set top box 2308 may not be required.

The set top box 2308 provides a video signal to the TV over HDMI or other display protocol. The set top box 2308 and/or a smart television 2318 may be preferred over a smartphone or a tablet because they can be controlled by a remote control 2312 that can be used from a distance, provide a larger display, and may be easier to use, especially for the elderly. Wireless connectivity like Bluetooth, Wi-Fi, etc. are typically available on current smart televisions or set-top boxes, or can be easily added via a USB interface. Such connections can again be used to exchange data between remote servers 2302, the exercise device 102 and to communicate with workout partners or personal trainers over the Internet 2306

For video communication, a camera 2310 may be in-built into the set-top set top box 2308 or the television 2318 TV. Alternatively, a camera with a wired USB interface can be connected to a USB interface on the set-top set top box 2308 or smart television 2318. Audio output can be provided by earbuds 2314 connected to the set top box 2308 or the smart television 2318, or by wired or wireless speakers 2316. A microphone may be built into the camera, the set-top box, may be connected to the set-top set top box 2308 via USB, or be included in wireless earbuds connected through Bluetooth.

Various examples are contemplated. Example 1 is a method of operating an exercise device including a platform on which a user can stand, and an electromagnetic force generator for generating an exercise force, the platform including force sensors, the method comprising: detecting at least one foot position on the platform using the force sensors of the platform; based on the at least one foot position being outside of a threshold of a preferred foot position, disabling the electromagnetic force generator; and based on the at least one foot position being within a threshold of a preferred foot position, activating the electromagnetic force generator.

In Example 2, the subject matter of Example 1 includes, wherein the threshold of the preferred foot position is in a front-back direction of the platform from a central exercise position on the platform.

In Example 3, the subject matter of Examples 1-2 includes, wherein the exercise device further includes one or more lights, comprising: based on the at least one foot position being outside of a threshold of an ideal foot position, prompting movement of a user's foot towards an ideal foot position using the one or more lights.

In Example 4, the subject matter of Examples 1-3 includes, wherein activating the electromagnetic force generator comprises generating an exercise force corresponding to an exercise force specified in an exercise routine.

In Example 5, the subject matter of Examples 1-4 includes, wherein the at least one foot position comprises a left foot position and a right foot position, and wherein the detecting at least one foot position comprises detecting the left foot position and detecting the right foot position, the method further comprising: based on the left foot position and the right foot position being within a threshold of alignment with each other from a central left/right position, activating the electromagnetic force generator; and based on the left foot position and the right foot position being outside the threshold of alignment with each other from the central left/right position, disabling the electromagnetic force generator.

In Example 6, the subject matter of Example 5 includes, wherein the threshold of alignment is in a front-back direction of the platform.

In Example 7, the subject matter of Examples 5-6 includes, wherein the threshold of alignment is in a side-to-side direction of the platform.

In Example 8, the subject matter of Examples 5-7 includes, wherein the exercise device further includes one or more lights, comprising: based on the left foot position and the right foot position being outside the threshold of alignment with each other, prompting movement of one of a user's feet towards the other one of the user's feet using the one or more lights.

Example 9 is a non-transitory computer-readable storage medium, the computer-readable storage medium including instructions that when executed by a computer, cause the computer to operate an exercise device including a platform on which a user can stand, and an electromagnetic force generator for generating an exercise force, the platform including force sensors, by performing operations comprising: detecting at least one foot position on the platform using the force sensors of the platform; based on the at least one foot position being outside of a threshold of a preferred foot position, disabling the electromagnetic force generator; and based on the at least one foot position being within a threshold of a preferred foot position, activating the electromagnetic force generator.

In Example 10, the subject matter of Example 9 includes, wherein the threshold of the preferred foot position is in a front-back direction of the platform from a central exercise position on the platform.

In Example 11, the subject matter of Examples 9-10 includes, wherein the exercise device further includes one or more lights, the operations further comprising: based on the at least one foot position being outside of a threshold of an ideal foot position, prompting movement of a user's foot towards an ideal foot position using the one or more lights.

In Example 12, the subject matter of Examples 9-11 includes, wherein activating the electromagnetic force generator comprises generating an exercise force corresponding to an exercise force specified in an exercise routine.

In Example 13, the subject matter of Examples 9-12 includes, wherein the at least one foot position comprises a left foot position and a right foot position, and wherein the detecting at least one foot position comprises detecting the left foot position and detecting the right foot position, the operations further comprising: based on the left foot position and the right foot position being within a threshold of alignment with each other from a central left/right position, activating the electromagnetic force generator; and based on the left foot position and the right foot position being outside the threshold of alignment with each other from the central left/right position, disabling the electromagnetic force generator.

In Example 14, the subject matter of Example 13 includes, wherein the exercise device further includes one or more lights, comprising: based on the left foot position and the right foot position being outside the threshold of alignment with each other, prompting movement of one of a user's feet towards the other one of the user's feet using the one or more lights.

Example 15 is an exercise device system, comprising: a platform on which a user can stand, the platform including force sensors; an electromagnetic force generator for generating an exercise force; and one or more processors, the one or more processors in use performing operations comprising: detecting at least one foot position on the platform using the force sensors of the platform; based on the at least one foot position being outside of a threshold of a preferred foot position, disabling the electromagnetic force generator; and based on the at least one foot position being within a threshold of a preferred foot position, activating the electromagnetic force generator.

In Example 16, the subject matter of Example 15 includes, wherein the threshold of the preferred foot position is in a front-back direction of the platform from a central exercise position on the platform.

In Example 17, the subject matter of Examples 15-16 includes, wherein the exercise device system further includes one or more lights, the operations further comprising: based on the at least one foot position being outside of a threshold of an ideal foot position, prompting movement of a user's foot towards an ideal foot position using the one or more lights.

In Example 18, the subject matter of Examples 15-17 includes, wherein activating the electromagnetic force generator comprises generating an exercise force corresponding to an exercise force specified in an exercise routine.

In Example 19, the subject matter of Examples 15-18 includes, wherein the at least one foot position comprises a left foot position and a right foot position, and wherein the detecting at least one foot position comprises detecting the left foot position and detecting the right foot position, the operations further comprising: based on the left foot position and the right foot position being within a threshold of alignment with each other from a central left/right position, activating the electromagnetic force generator; and based on the left foot position and the right foot position being outside the threshold of alignment with each other from the central left/right position, disabling the electromagnetic force generator.

In Example 20, the subject matter of Example 19 includes, wherein the exercise device system further includes one or more lights, comprising: based on the left foot position and the right foot position being outside the threshold of alignment with each other, prompting movement of one of a user's feet towards the other one of the user's feet using the one or more lights.

Example 21 is at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement of any of Examples 1-20. Example 22 is an apparatus comprising means to implement of any of Examples 1-20. Example 23 is a system to implement of any of Examples 1-20. Example 24 is a method to implement of any of Examples 1-20.

As referred to herein, the term non-transitory machine-readable medium refers to a single or multiple storage devices and/or media (e.g., a centralized or distributed database, and/or associated caches and servers) that store executable instructions and/or data. The terms shall accordingly be taken to include, but not be limited to, solid-state memories, and optical and magnetic media, including memory internal or external to processors. Specific examples of machine-storage media, computer-storage media and/or device-storage media include non-volatile memory, including by way of example semiconductor memory devices, e.g., erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), FPGA, and flash memory devices (external or internal to processor); magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

Changes and modifications may be made to the disclosed examples without departing from the scope of the present disclosure. These and other changes or modifications are intended to be included within the scope of the present disclosure, as expressed in the following claims as filed or amended.