INERTIA MITIGATION SYSTEM

Abstract

In all applications of force, all components, internal or external, moving or otherwise, have inertia associated with their mass and geometry. The inertia of the components, internal or external, moving or otherwise, is detrimental to the precision and/or accuracy of the force being applied by and/or to the system, whether the force is applied internally or externally to the system. A motorbased system and/or a method involves mitigating and/or reducing force errors caused by the inertia of the components, internal or external to the system, moving or otherwise, in systems built for the application of force, the forces being internal or external to the system. This is achieved, in part, by addressing the inertial effects of components in the load-application path, including a motor and/or other force-generating devices, force transmitting elements, and carriers of force between a motor and those elements that contribute to force error due to inertial effects.

Claims

1. An exercise machine, comprising: an electro-mechanical device powering the exercise machine that has sufficient dynamic response such that a user feels only the commanded force plus the minimized error determined by a minimum resistance setting for the machine and maximum acceleration for which the machine is used or specified to be used.

2. The exercise machine of claim 1, further comprising: a pulley; and a cable configured to be at least partially wound around the pulley and to be connected to the electro-mechanical device.

3. The exercise machine of claim 2, further comprising: a grip, wherein a first end of the cable is connected to the electro-mechanical device and a second end of the cable is connected to the grip; and an inertial measurement unit (IMU) provided in the grip and configured to measure specific force applied to the grip, angular rates of the grip and orientation of the grip.

4. The exercise machine of claim 3, further comprising a hardware embedded processor configured to: receive the specific force of the grip, the angular rates of the grip and the orientation of the grip from the IMU via an electrical connection with the IMU, and control the electro-mechanical device based on the specific force of the grip, the angular rates of the grip and the orientation of the grip to counteract inertia in the system by adjusting a torque outputted by the electro-mechanical device to provide a more linear feel to the user applying a force to the cable.

5. The exercise machine of claim 4, wherein a mechanism is added to periodically reset the error that accumulates in a reported position and orientation of an IMU over time, such that the acceleration reported by the sensor remains sufficiently accurate over the course of an exercise session such that when the signal is used to compensate for system inertial effects, system force error remains below the additive sum of the minimum resistance setting and maximum intended force error of the system.

6. An exercise machine, comprising: an electro-mechanical device powering the exercise machine that has sufficient dynamic response such that a user feels only the commanded force plus the minimized error determined by a minimum resistance setting for the machine and maximum acceleration for which the machine is used or specified to be used; a frame; an arm through which the cable passes; a locking plate attached to the frame; and a vertical locking mechanism configured to lock the arm relative to the locking plate.

7. The exercise machine of claim 6, wherein the locking plate includes a plurality of teeth and is fixed to the frame, and wherein the vertical locking mechanism includes a locking tooth that engages a space between two adjacent teeth among the plurality of teeth to lock the arm vertically.

8. The exercise machine of claim 7, wherein the locking plate teeth, voids, and locking tooth are not trapezoidal, such that engagement of the locking tooth on top of a sector tooth will be unstable and cause the locking tooth to slide into and engage a void, rather than a sector tooth.

9. The exercise machine of claim 7, wherein the vertical locking mechanism further includes a spring connected to the locking tooth, the spring being configured to apply a preload to the locking tooth in order to minimize relative movement between the arm and the locking plate.

10. An exercise machine, comprising: an electro-mechanical device powering the exercise machine that has sufficient dynamic response such that a user feels only the commanded force plus the minimized error determined by a minimum resistance setting for the machine and maximum acceleration for which the machine is used or specified to be used; and a flat plate force sensor that is attached to a pulley over or under which a cable passes, where said cable is at least part of the load path between the electro-mechanical device and physical user implement.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

[0020] FIG. 1A is a perspective view of the system of the present invention and FIG. 1B is a view of a cable and hand grip.

[0021] FIG. 2 is a perspective view of the system according to the present application and is a simplified version of FIG. 1A, with a system that includes two arms.

[0022] FIG. 3 is a perspective view of the system of FIG. 2.

[0023] FIG. 4 is a side view of an arm locking mechanism of FIG. 3.

[0024] FIG. 5 is a zoomed in side view of the arm locking mechanism of FIG. 4.

[0025] FIG. 6 is a perspective view of the locking mechanism of FIG. 4.

[0026] FIG. 7 is a perspective view of an alternate embodiment of a locking mechanism according to the present invention.

[0027] FIGS. 8A-8C illustrate a telescoping/extension locking mechanism for locking the inner tube with respect to the outer tube.

[0028] FIG. 9 illustrates a cross-sectional view of a cable passing through a load cell according to an embodiment of the present invention.

[0029] FIG. 10 is a perspective view of a pulley according to an embodiment of the present invention.

[0030] FIG. 11 is perspective view of a spoke cable spool according to an embodiment of the present invention.

[0031] FIG. 12 illustrates a cross-sectional view of another embodiment of a locking mechanism for vertical pivot of the present invention.

[0032] FIG. 13 is a perspective view of the hand grip attached to a cable joint according to an embodiment of the present invention.

[0033] FIG. 14 is a perspective view of a spoke spool having a cable wound therearound according to an embodiment of the present invention.

[0034] FIGS. 15-18 illustrate different views of the locking plate according to an aspect of the present invention.

[0035] FIG. 19 illustrates a locking mechanism, including a locking plate, for locking each arm of the machine.

[0036] FIG. 20 is an alternate embodiment of the cable spool which is solid and includes grooves/cutouts according to an embodiment of the present invention.

[0037] FIG. 21 illustrates a load cell assembly mounted in a frame according to an embodiment of the present invention.

[0038] FIG. 22 is a perspective view illustrating additional features of the load cell of FIG. 21.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The present invention will now be described with reference to the accompanying drawings, wherein the same reference numerals have been used to identify the same or similar elements throughout the several views.

[0040] When using an IMU, or other sensors able to determine the acceleration of a body, drift (e.g., is the low frequency change in a sensor with time often associated with electronic aging of components or reference standards in the sensor) in the acceleration vector is a common occurrence. The present invention addresses this drift problem in one of several ways, each of which can be performed by a controller of the system.

[0041] The first method to address the drift problem is by periodically resetting the acceleration and directional values reported by the sensor when they are at a known orientation, position, velocity, or acceleration. Such a reset can keep sensor drift below a limit to produce acceptable accuracy and to address inertia-driven force disturbances in a motor-based fitness equipment solution.

[0042] For illustrative purposes, one way, but not the only way, to achieve a reset to a known orientation, position, velocity, or acceleration value for a sensor is to require the sensor to be deposited in a receptacle with known characteristics at the end of an exercise. Alternately, when other sensors detect the sensor is in a relatively unchanging position or near zero velocity, the acceleration-measuring sensor can be assumed to be in a known orientation that will allow the reset of the acceleration vector to a known value.

[0043] A second method to address the drift problem can be to use a global positioning system (GPS), a local positioning system (LPS), or an optical position/motion detection system to reset the acceleration sensor to a known value, thereby eliminating drift.

[0044] A third method to address the drift problem can be to use a sensor that is not subject to drift, such as a GPS, LPS, or optical position/motion detection sensor as the primary data source, and to use an IMU to provide intermediate data points only. As an example, most optical systems rely on frame rates that are on the order of 30 frames per second. By providing updates between primary sensor frames, the IMU can be used to increase the resolution of the acceleration value reported by the primary sensor.

[0045] A fourth method to address the drift problem is to double integrate acceleration over time (which produces position) knowing that the resulting position must reside within the user's exercise space, and if not subtract out the accumulated drift as it relates to acceleration bias.

[0046] For motor-based fitness equipment, the goal is to reduce inertial effects due to acceleration to a level below an acceptable predetermined threshold. For a specified set of requirements, i.e., force and rate, there exist a motor, inertia and mass solution that will meet those requirements. The motor and inertia requirements the analysis yields can not be possible to build with current motor topologies.

[0047] The control solution of the present invention to reduce inertia effects due to acceleration is now explained. A force control loop is employed where the command from the controller (e.g., hardware embedded processor) is the user requested resistance. The user can request resistance by either inputting a resistance level to a user interface (e.g., a display connected to a hardware-embedded processor and hardware-embedded memory) of the system, as shown in FIG. 1A, or in any manner known in the art. In the present invention, force feedback comes from a rigid load sensor (i.e., IMU) that is placed on the cable path close to the user. This minimizes inertia and dynamics between user and rigid load sensor. For instance, the rigid load sensor can be mounted on a hand grip of the cable (e.g., on hand grips of the cables), as discussed above and shown FIG. 1B below.

[0048] By mounting the load sensor rigidly fixed on the cable path close to the user, there is a reduction in compliance (i.e., relative movement between the sensor and the cable), which produces a more accurate acceleration (e.g., acceleration vector) applied coaxially to the cable.

[0049] A conditioned or corrected force error is formed by subtracting the command from the feedback, which is then filtered by the PID and feed-forward conditioning, and is then subsequently converted to a motor current command by a motor controller, where units of force are translated to units of current. This control is a PI filter (proportional-plus-integral) using measured current (e.g., of the motor) as the feedback applied sinusoidally for smoothness (cogging and torque ripple eliminated) according to motor poles and phases. This affords the user smooth and accurate cable resistance for any motion imparted, in the instances where cable resistance is provided due to resistance from the motor.

[0050] In the absence of an acceleration term, the present invention can include limiting the inertia of components in the load path, such that when that inertia is multiplied by the accelerations at which the machine is intended to operate, the magnitude of that term is less than the additive combination of the minimum resistance setting of the machine and the maximum resistance error acceptable for that machine, provided that the motor can overcome its own inertia. It is understood that the maximum resistance error cannot be larger than the minimum resistance setting in order to avoid a case of slack in the cable.

[0051] The components in the load path can include a motor (including the corresponding components of the motor), pulleys, a cable spool, the cable itself (e.g., a cable comprised of synthetic fibers or steel, or any material), any and all pulley(s), grip(s), all bearings and all linkages. Further, the present invention contemplates the elimination of or at least reduction of slack and/or slop (e.g., play or free play) in all joints and structural elements, and the rotational position sensor. For instance, as illustrated in FIGS. 3-9 and 12, a preload can be applied to a locking mechanism, which locks an arm holding the cable, such that there is minimum slack in the locking mechanism.

[0052] That is, known exercise machines have a lot of slack (e.g., undesired movement), including machines having arms which utilize a pin to lock the arms in place, and machines using unloaded sector plates or geared locking mechanisms, with cables extending through the arms and the arms being movable to adjust a height of the cable with respect to a user. This slack between the various components of known exercise machines contributes to a larger error when calculating a force input applied by the user to the cable. In other words, slack between components allows more elements to move, which in turn adds undesirable and unanticipated inertia to the system.

[0053] In contrast to the known exercise machines, the present invention seeks to limit (e.g., reduce) the inertia of components of the system, especially components in the load path, such that when that inertia, when multiplied by the acceleration(s) at which the machine is intended to operate, produces a term of magnitude less than the additive combination of the minimum resistance setting of the machine and the maximum resistance error acceptable for that machine, which can be assumed to be 50% of the minimum force setting, for example.

[0054] Components with low inertia include, but are not limited to, a motor, a motor rotor, a cable spool, a cable itself (e.g., comprised synthetic fibers, steel or the like), any and all pulleys, grip(s), all bearings, and all linkages in the load path from the motor rotor to the user implement grip(s). Further, the present invention contemplates the elimination of or at least reduction of slack and/or slop in all joints and structural elements, and additionally the rotational position sensor. The cable can be comprised of synthetic fibers (e.g., Kevlar), carbon fiber, etc., or can be comprised of steel. However, regardless of materials chosen, the cables must have an extension in tension of less than 3% of the cable length under tension to assure the precision operations.

[0055] An inertial measurement unit (IMU), is known in the art as an electronic device that measures and reports a body's specific acceleration, angular rate, and the orientation of the body, using a combination of accelerometers, gyroscopes, and sometimes magnetometers. The IMU can include multiple accelerometers, can perform multiple angular rate measurements and can be provided in the grip (e.g., hand grip in FIGS. 1B and 13) of the system. The measurements provided by the IMU can be used, for example, by a controller (e.g., a hardware embedded processor, which can include memory for storing algorithms for performing the described structure) of the system, to cancel or minimize inertial effects of the various components of the system. That is, the IMU can be electrically connected or wirelessly connected (e.g., as known in the art) to the controller in order to send the controller the measurements (specific force, angular rate, and the orientation of the body).

[0056] The IMU can provide a force vector in 3-D space to allow the controller to better control the motor (e.g., electro-mechanical device), in order to reduce potential slack of the cable and improve the accuracy of resistance applied to the cable. That is, if slack is present in the system, the resistance applied to the cable by the motor will not correspond to the resistance inputted by the user to the system, and further, would result in a lurching effect during movement of the cable (e.g., while performing an exercise). Placing the IMU at the hand grip or other physical user implement (e.g., mechanism in which the user interacts with, other than the hand grip) results in a relatively low noise level, which can then be fed into a filter to reduce any remaining noise level to near zero (or possibly to zero).

[0057] The system of the present invention can include any type of motor, however, it is preferred to utilize an axial flux motor (e.g., a dual rotor axial-gap motor), an electrostatic motor, or a Halbach array motor, as each of these motors can contribute to a reduction of inertia.

[0058] A Halbach array is arrangement of permanent magnets that creates a stronger field on one side while reducing the field on the other side to near zero by orienting the magnets so that their poles are out of phase. The Halbach array can be operated as a brushless direct current (DC) (BLDC motor) or as a brushless alternating current (AC) (BLAC) motor (also referred to as a permanent magnet synchronous motor or PMSM). Utilization of a Halbach array to handle rotor flux reduces the need for mass of the rotor, as it results in greater concentration of magnetic flux on the face of rotor. That is, since less material is needed, the Halbach array motor has less mass and therefore less inertia. Electric motors based on the Halbach array offer increased power density and high efficiency, which is also partially enabled because lamination or back iron is not needed, resulting in a motor that is essentially ironless and which therefore reduces eddy current losses and hysteresis losses (e.g., core losses or iron losses). Therefore, the Halbach array results in a maximum field strength and a minimum mass to a practical extent.

[0059] An axial flux motor (e.g., an axial gap motor) has a gap between the rotor and stator, and therefore the direction of magnetic flux between the rotor and stator is aligned in parallel with the axis of rotation (e.g., of the motor), rather than radially as with the concentric cylindrical geometry of a radial gap motor. One version applicable of an axial flux motor includes a dual rotor axial-gap motor, in which torque is produced on each face of the motor instead of one side, which provides two air gaps that produce torque. Dual rotor axial-gap motors provide increased power density with reduced weight and size, thereby resulting in a reduced inertia.

[0060] An electrostatic motor (e.g., capacitor motor) is based on Coulomb forces, and its energy output is related to the change in electrostatic energy that occurs when charges are moved between the terminals of a high-voltage (HV) supply, whereas a regular motor is based on magnetic forces and a change of magnetic-dipole energy within a magnetic field. Electrostatic based motors intrinsically have low inertia.

[0061] Further, the present invention contemplates motors having high winding counts or high phases, including four phase, five phase and six phase, but is not limited thereto. For example, at least two phases to any number of phases may be utilized. The increased windings or increased phases results in an increased torque density, which reduces inertia. The increase in phases results in closer to peaks on the sine wave of an output of the motor, which results in increased torque density and allows for the motor to be downsized, which decreases inertia. The present invention can utilize a permanent magnet AC motor or a permanent magnet brushless synchronous motor (brushless-sinusoidal or square wave type).

[0062] FIGS. 1A and 1B of the present application, reproduced below, illustrate a system (e.g., an exercise device) including a tower (e.g., frame), a motor, a cable spool (i.e., spool), various pulleys, a carriage, an arm, a cable and a hand grip. FIG. 1A is a perspective view of the system of the present invention and FIG. 1B is a view of the cable and hand grip. Only one arm is illustrated, however, a plurality of arms and corresponding components (i.e., tower, motor, spool, pulleys, cable and hand grip) can be provided, as illustrated in FIGS. 2 and 3. In performing an exercise, a user sets a resistance level via the user interface, grips the hand grip and performs a movement (i.e., exercise).

[0063] The system of the present invention can be an exercise machine, but is not limited thereto. Other applications include robotic surgery, exoskeletons, industrial automation/manufacturing robotics, multi-axis machine tools, warehouse robotics, robotics generally, and motor-based exercise machines including those that exclusively include a cable in a portion of the load path between the motor and user, as well as those that do not include a cable in a portion of the load path between the motor and user. The motor can include the cable spool, that is, the cable spool can be fixedly attached to the motor, such as by fasteners (e.g., bolts, screws and the like), and rotation of the motor can directly cause rotation of the cable spool.

[0064] A first end of the cable can be fixedly attached to the cable spool and rotation of the motor can directly cause rotation of the cable spool, which causes the cable to be wound onto the cable spool or to be unwound from the cable spool (see FIG. 14, for example). The cable passes through a plurality of pulleys, including a first pulley positioned in-line with the cable spool (i.e., along a same plane as the cable spool such that the cable maintains a particular height), then through a second pulley that is oriented about 90 with respect to the first pulley (see FIG. 22, for example). Further, the cable can then pass through an optional third pulley, through a hole (e.g., axially extending hole) in the arm, then through optional fourth and fifth pulleys. A second end of the cable can be attached to a hand grip via a cable joint. The cable joint can include an IMU as discussed above. The fourth and fifth pulleys can be adjacent one another and have the same orientation, such that the cable passes through a space between the fourth and fifth cables (see FIG. 8B, for example).

[0065] The pulleys can be provided with a minimum pulley diameter to meet minimum bend requirements of the cable, to reduce inertia. Further, one face of the cable spool can be incorporated into a motor rotor (i.e., one face of the cable spool can be a part of a motor rotor or the cable spool and a motor rotor can be a single integral unit), in order to minimize dedicated inertia in the load path. Further, the cable spool can have a spoked design, as illustrated in FIG. 11. Use of a spoked design of the cable spool provides sufficient structural rigidity and strength while minimizing inertia.

[0066] FIG. 2 is a perspective view of the system according to the present application and is a simplified version of FIG. 1A, with a system that includes two arms. The two arms are pivotable in a horizontal direction and a vertical direction and are also extendable/telescoping. That is, as described below, each arm has at least one movable member (e.g., inner tube) that translates (e.g., moves) along an axial direction relative to a fixed member (e.g., outer tube).

[0067] FIG. 3 of the present application illustrates a perspective view of the system of FIG. 2, which illustrates details of the arms. Each arm (e.g., arm carriage) can pivot via top gear plates engaging a respective tower plate disposed on the tower, so as to allow the arms to translate in a horizontal direction (e.g., lateral direction of the arm). The tower plate can include locking members that engage a space between gear teeth of the top locking plates (e.g., top gear plates), as shown in FIGS. 3 and 4. This locking feature is also referred to as the horizontal locking mechanism and can be exactly the same (or similar) to the vertical locking mechanism illustrated in FIGS. 6-8 and described below.

[0068] FIGS. 4-6 of the present application illustrate a locking mechanism (e.g., vertical locking mechanism) of each arm, which is the same as the horizontal locking mechanism shown in FIG. 3 with a different orientation. The locking mechanism includes a locking plate, which can be in the form of a fixed semi-circular locking plate which is mounted to a frame of the tower, an anti-translation plate including a locking pawl (e.g., locking gear tooth) that engages the locking plate (e.g., a space between protrusions or teeth of the locking plate), and a spring (e.g., locking spring) or other actuator that applies a preload to the anti-translation plate to lock the arm to the tower (e.g., in a specific vertical position). The arm further includes an inner tube and outer tube.

[0069] The locking spring can be a coil tension or compression spring, a machined spring, a leaf spring or torsion spring or any other type of spring, or a gas cylinder or fluid cylinder, or friction plate or cylinder. The unlocking device can be a gas cylinder or fluid cylinder, a screw motor, a cam, a manual lever, a manual screw, a solenoid or any other actuating device.

[0070] The shape of the locking plate described above is very important. It is important that the locking feature is such that the anti-translation bar/plate cannot be engage in such a way that it lands in a stable position on the top of the locking plate. The locking features (e.g., locking pawl of the locking mechanism) and teeth of the locking plate) do not have a trapezoidal shape to assure the locking mechanism is not mis-engaged by resting on top of a gear tooth when locked (which can be the case with trapezoidally shaped teeth/protrusions that engage one another). For example, potential teeth implementations, their associated voids, and locking mechanisms should be triangular, or be shaped like cones with rounded tops, or any shape such that when locked, there is no risk (e.g., minimized risk) of a locking mechanism resting on top of a tooth of the locking plate.

[0071] The spring can be provided in plurality, as shown in FIGS. 4-6 and 8, and can radially surround a rod that is connected to a hydraulic cylinder. Activation of the hydraulic cylinder, such as by a user (e.g., user activation), causes the spring(s) to be compressed, which unlocks the locking paw from the locking plate, thereby allowing the arm to move vertically. Once the springs are disengaged, a user can manipulate (e.g., move) the arm to a different vertical position, and once the hydraulic cylinder is deactivated (e.g., by a user), the arm can be locked into this new different vertical position (e.g., the locking paw engages a space between different teeth of the locking plate, that is, it engages a different position). Due to the utilization of the hydraulic cylinder, the preload applied by the springs is equal to or greater than the force required to move the locking plate from engagement and can be relatively high to resist movement of the arm relative to the carriage, thereby reducing inertia and undesired movement of the system (e.g., eliminating all compliance and/or any motion of the locking mechanism). For instance, the pre-load applied by the springs can be constantly applied and can amount to a predetermined amount, such as 400 ft-lbs. The purpose of the hydraulic cylinder to disengage the spring, which is not possible without the hydraulic cylinder or a large lever arm.

[0072] The spring(s) can be connected to first and second joints, and the first and second joints can be connected (e.g., such as by welding, brazing, fastening and the like) to a outer tube of the arm. The spring(s) can include a housing having a first end having an extension with a hole and a second end having an extension with a hole. The spring(s) can be attached to the first joint by a rod/pin extending through the first joint (e.g., a hole of the first joint or holes of two arms of the first joint) and through the hole of the extension, and the rod/pin can be fixed into place by a locking collar. The locking collar can engage a groove of the rod/pin and can be provided in plurality to lock two sides of the rod/pin in-place relative to the first joint. Similarly, the springs(s) can be attached to the second joint by a rod/pin extending through the second joint (e.g., a hole of the second joint or holes of two arms of the second joint) and through the hole of the extension, and the rod/pin can be fixed into place by a locking collar. The locking collar can engage a groove of the rod/pin and can be provided in plurality to lock two sides of the rod/pin in place relative to the second joint.

[0073] FIG. 7 involves another embodiment of a locking mechanism according to the present invention, in which a lever is used to cause the locking pawl to engage (e.g., lock) or disengage its connection to the locking plate. A pre-load is applied to the locking pawl via a cam and at least one spring. Although two springs are shown, greater or fewer springs can be employed in this embodiment. The cam can be designed such that when the locking bar is engaged, it is in a stable position and resists the forces in a direction for disengaging the lock.

[0074] FIGS. 8A-8C illustrate a telescoping/extension locking mechanism for locking the inner tube with respect to the outer tube. The inner tube can be disposed within the outer tube and can be movable relative to the outer tube. At least one spring can be used, but preferably two springs are used and the spring(s) can be attached between two plates via corresponding fasteners (i.e., bolts and nuts). The spring(s) apply a force (e.g., clamping force) to clamp (e.g., fix) the inner tube to the outer tube. A first plate among the two plates can be fixed to the outer tube, and a second plate among the two plates can be fixed to the inner tube, such that the spring(s) located therebetween exhibit the clamping force onto the first and second plates.

[0075] The inner tube is split axially with a single slit, as shown in FIG. 8C. The slit may extend along an entire axial length of the inner tube, or alternatively may extend only up to an end of the sleeve surrounding the inner tube. The sleeve can be affixed to the outer tube and can surround the inner tube. The second plate can be affixed to the inner tube and bolted rigidly to a rectangular arm. The first plate can be fixed to the sleeve. There can be a gap between the two plates (first and second plates). Springs are used, as shown, to force the two plates together, which causes the inner tube to expand due to the presence of the slit of the inner tube, thereby clamping the inner tube onto the sleeve (the sleeve being fixed). A hydraulic cylinder is used to release the clamping force thereby allowing the cylindrical arm to be adjusted, and can be attached to the sleeve.

[0076] The telescoping/extension locking mechanism further includes a hydraulic mechanism (e.g., hydraulic piston/cylinder) that compress the spring(s) to disengage the spring(s), which allows a user to translate/slide the circular tube relative to the outer tube to effectively increase or decrease the length of the arm. This can be done to perform different exercises.

[0077] This locking mechanism can also be applied to the elevation and rotation axes of the machine to provide a solution with infinite adjustability of arm positions. Where the locking plate/locking bar described above is limited to locking positions determined by sector plate voids, the clamping mechanism described above can provide infinite adjustability of arm position when applied to other axes of arm motion.

[0078] FIG. 9 illustrates a cross-sectional view of the system of the present invention, in which a synthetic cable is employed to reduce inertia, and which is rotatably mounted to various pulleys, as described above with respect to FIG. 1A.

[0079] The unique geometry of the force sensor to which the center pulley in FIG. 9 is attached is a critical feature of the present invention. By mounting the center pulley directly to the face of a flat plate force sensor, higher accuracy and longer sensor life are achieved. The pulley is attached offset relative to the force sensor thereby creating a moment on the force sensor that causes it to deflect in pure bending and eliminates any torsional loads on the sensor. This geometry is lower in cost relative to conventional load cells and S-Beam type sensors (as known in the art). Furthermore, the sensor as described above allows for use of lower cost strain gauges, since full bridge strain gauges are not required. The load cell is rigidly mounted and secured from all four sides, and is isolated from any sort of deflection, including torsional loads.

[0080] FIG. 10 is a perspective view of a pulley that is representative of each of the pulleys of the system according to the present invention. Each of the pulleys are optimized to reduce rotational inertia by having a reduced diameter, and can include spoking as described for the cable spool above, and/or can include lightweight materials, such as aluminum or magnesium, to result in a a reduced rotational inertia.

[0081] FIG. 11 is perspective view of a spoke cable spool, which has a reduced mass as compared to a solid cable spool, thereby reducing inertia (e.g., rotational inertia).

[0082] FIG. 12 illustrates a cross-sectional view of another embodiment of a locking mechanism for vertical pivot (e.g., a vertical locking mechanism), which employs a disc brake (e.g., hydraulic disc brake as known in the art) that rotates about a semi-circular member (e.g., stator) and can clamp down on the stator to cause the pivotable arm (e.g., arm) to lock into place, thereby securing a vertical position of arm. Further, this embodiment can be employed in each arm of the system.

[0083] FIG. 13 is a perspective view of the hand grip, which can be attached to the cable joint by a carabiner. The cable is attached to the cable joint in a manner as known in the art. A synthetic material, such as an elastomeric material, can be attached to the hand grip, and the synthetic material can be attached to a carabiner. The carabiner can be attached to a closed loop, and the cable can be attached to the closed loop. However, the present application is not limited thereto.

[0084] FIG. 14 is a perspective view of a spoke spool having a cable wound therearound.

[0085] FIGS. 15-18 illustrate different views of the locking plate according to an aspect of the present invention. If the locking plate uses teeth or protrusions that uses flat surface on the tip of them (i.e., a flat top surface), then the pawl can rest the flat top surface instead of being locked into position between the protrusions. Therefore, the rounded protrusions and rounded roots of FIGS. 15-18 are utilized because they are always unstable at the tip and will only have stability between the protrusions. That is, this locking feature results in less user error and minimizes or eliminates positioning the pawl onto a tip of the protrusion of the locking plate. Therefore, the locking plate of FIGS. 15-18 provides particular benefits over the locking plate of FIGS. 4-6. The locking plate and corresponding mechanisms of FIGS. 15-18 can be used in the machine of any of the figures (that is, can replace the locking plate of FIGS. 1-7).

[0086] FIG. 19 illustrates a locking mechanism, including a locking plate, for locking each arm of the machine. The locking mechanism can be utilized for any pivot direction, such as a horizontal direction or a vertical direction. Additionally, any type of actuator can be used to lock a paw (e.g., gear) to a gear(s)/protrusion(s) of the locking plate, as shown. FIG. 19 illustrates an anti-translation plate, which locks the gear/locking pawl and prohibits the locking pawl from sliding in any direction, including from left or right (e.g., from side to side, perpendicular to an extension direction of the paw/gear(s) of the locking plate).

[0087] FIG. 20 is an alternate embodiment of the cable spool (e.g., spool) which is solid and includes grooves/cutouts. The grooves/cutouts reduce the mass and inertia of the spool, and the spool is non-spoked.

[0088] A non-contacting guide is implemented around the outer radius of the spool to reduce the risk of a loose or slack cable jumping out of its intended path around the spool. Such a guide may be implemented around pulleys in the system. Similarly, guides may be implemented through linear spaces traversed by the cable between the spool and user implement to avoid cable escapes, tangling, and fouling.

[0089] FIG. 21 illustrates a load cell assembly mounted in a frame according to an embodiment of the present invention. The load cell assembly is as known in the art, which is also known as a force transducer or a strain gauge, which converts a force, such as tension, compression, pressure, or torque, into an electrical signal that can be measured and standardized. For instance, an increasing force to the load cell results in proportional changes to the generated electrical signal. The load cell can be pneumatic, hydraulic or electric and can detect any type of force, as known in the art.

[0090] FIG. 22 is a perspective view illustrating additional features of the load cell of FIG. 21. The load cell according to FIG. 22 is contained within rigid members (e.g., plates/frame members) to isolate the load cell from loads and deflections in the system. This results in a pulley with minimal or no movement relative to the load/deflection. Further, the cable, described above, passes around a pulley, which is mounted in a cantilevered configuration, which imparts pure bending of the load cell to measure a force applied to the cable. This feature allows for no torsional loads being applied to the load cells, and allows for the use of an axial strain gauge only, and does not require the use of strain gauge rosettes (e.g., or bridges to accommodate torsional loads, as in the prior art).

[0091] The present invention encompasses various modifications to each of the examples and embodiments discussed herein. According to the invention, one or more features described above in one embodiment or example can be equally applied to another embodiment or example described above. The features of one or more embodiments or examples described above can be combined into each of the embodiments or examples described above. Any full or partial combination of one or more embodiment or examples of the invention is also part of the invention.

[0092] Various embodiments described herein can be implemented in a computer-readable medium using, for example, software, hardware, or some combination thereof. For example, the embodiments described herein can be implemented within one or more of Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), Field Programmable Gate Arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a selective combination thereof. In some cases, such embodiments are implemented by the controller. That is, the controller is a hardware-embedded processor executing the appropriate algorithms (e.g., flowcharts) for performing the described functions and thus has sufficient structure. Also, the embodiments such as procedures and functions can be implemented together with separate software modules each of which performs at least one of functions and operations. The software codes can be implemented with a software application written in any suitable programming language. Also, the software codes can be stored in the memory and executed by the controller, thus making the controller a type of special purpose controller specifically configured to carry out the described functions and algorithms. Thus, the components shown in the drawings have sufficient structure to implement the appropriate algorithms for performing the described functions.

[0093] The present invention being thus described, it will be obvious that the same can be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.