Magnetic sensor arrays and methods of making and using thereof

Abstract

Described herein magnetic sensor array that comprise a plurality of magnetic force sensors disposed in relative position with respect to one another within a matrix. In some embodiments, the plurality of magnetic force sensors can be integrated within the matrix at relative positions with respect to one another to create a 2-dimensional or 3-dimensional array of sensors within the matrix.

Description

[0001] Attorney Docket No. 10776-035W01

[0002] MAGNETIC SENSOR ARRAYS AND METHODS OF MAKING AND USING THEREOF

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims benefit of priority of U.S. Provisional Application No. 63 / 679,566, filed August 5, 2024, which is incorporated herein by reference in its entirety.

[0005] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0006] This invention was made with government support under HL152410 and EB034605 awarded by the National Institutes of Health. The government has certain rights in the invention.

[0007] BACKGROUND

[0008] Force sensors play a critical role in a wide range of applications, including robotics, wearable devices, medical diagnostics, prosthetics, industrial automation, and tactile sensing systems. Conventional force sensing mechanisms, such as piezoresistive, capacitive, and optical sensors, have been widely used to detect mechanical loads. While effective in certain contexts, these technologies often suffer from limitations such as limited sensitivity, susceptibility to electromagnetic interference, reduced spatial resolution in large- area applications, and challenges in achieving flexible or conformable form factors.

[0009] Magnetic force sensors, particularly those utilizing magneto-sensitive elements such as Hall effect sensors, magnetoresistive sensors, or giant magnetoresistive (GMR) devices, offer unique advantages in detecting force-induced changes in magnetic fields. When integrated with magnetic materials (e.g., permanent magnets or magnetic composites), these sensors can provide robust and contactless measurements of applied forces, deformations, or displacements. However, the development of scalable, high-resolution magnetic force sensor arrays remains a technical challenge.

[0010] Conventional approaches to magnetic force sensing are often limited to single-point detection or rely on complex wiring and signal conditioning schemes that hinder scalability and integration. Moreover, magnetic crosstalk between adjacent sensing elements in an array can lead to reduced accuracy and difficulty in interpreting force distribution patterns. Attorney Docket No. 10776-035W01

[0011] There is a growing demand for systems that can accurately map distributed mechanical forces across a surface while maintaining high sensitivity, low power consumption, mechanical flexibility, and manufacturability.

[0012] SUMMARY

[0013] Described herein magnetic sensor array that comprise a plurality of magnetic force sensors disposed in relative position with respect to one another within a matrix. In some embodiments, the plurality of magnetic force sensors can be integrated within the matrix at relative positions with respect to one another to create a 2-dimensional or 3 -dimensional array of sensors within the matrix. Magnetic sensor array can then measure forces acting on the matrix. When integrated within a device or deployed on a surface, the sensor array can efficiently measure forces acting on the device or surface. Likewise, when worn by a user, the sensor can efficiently measure forces acting on the user. The sensor arrays described herein can find use in a wide range of applications, as described in more detail below.

[0014] In some embodiments, the matrix comprises an elastomeric matrix. In certain embodiments, the elastomeric matrix comprises a crosslinkable composition, such as a crosslinkable silicone composition.

[0015] In some embodiments, the magnetic sensor array comprises from 2 to 50 magnetic force sensors, such as from 5 to 50 magnetic force sensors, from 5 to 40 magnetic force sensors, from 5 to 30 magnetic force sensors, from 5 to 25 magnetic force sensors, from 5 to 20 magnetic force sensors, from 5 to 15 magnetic force sensors, from 8 to 50 magnetic force sensors, from 8 to 40 magnetic force sensors, from 8 to 30 magnetic force sensors, from 8 to 25 magnetic force sensors, from 8 to 20 magnetic force sensors, or from 8 to 15 magnetic force sensors.

[0016] In some embodiments, the matrix comprises a film or sheet. In some embodiments, the film or sheet has a thickness of less than 10 mm, such as a thickness of less than 9.5 mm, less than 9 mm, less than 8.5 mm, less than 8 mm, less than 7.5 mm, less than 7 mm, less than 6.5 mm, less than 6 mm, less than 5.5 mm, less than 5 mm, less than 4.5 mm, less than 4 mm, less than 3.5 mm, less than 3 mm, less than 2.5 mm, less than 2 mm, or less than 1.5 mm. In certain examples, the film or sheet has a thickness of from 0.5 mm to 7.5 mm, such as a thickness of from 0.5 mm to 7 mm, from 0.5 mm to 6.5 mm, from 0.5 mm to 6 mm, from 0.5 mm to 5.5 mm, from 0.5 mm to 5 mm, from 0.5 mm to 4.5 mm, from 0.5 mm to 4 mm, from 0.5 mm to 3.5 mm, from 0.5 mm to 3 mm, from 0.5 mm to 2.5 mm, from 0.5 Attorney Docket No. 10776-035W01 mm to 2 mm, from 0.5 mm to 1.5 mm, from 0.75 mm to 7.5 mm, from 0.75 mm to 7 mm, from 0.75 mm to 6.5 mm, from 0.75 mm to 6 mm, from 0.75 mm to 5.5 mm, from 0.75 mm to 5 mm, from 0.75 mm to 4.5 mm, from 0.75 mm to 4 mm, from 0.75 mm to 3.5 mm, from 0.75 mm to 3 mm, from 0.75 mm to 2.5 mm, from 0.75 mm to 2 mm, from 0.75 mm to 1.5 mm, from 1 mm to 7.5 mm, from 1 mm to 7 mm, from 1 mm to 6.5 mm, from 1 mm to 6 mm, from 1 mm to 5.5 mm, from 1 mm to 5 mm, from 1 mm to 4.5 mm, from 1 mm to 4 mm, from 1 mm to 3.5 mm, from 1 mm to 3 mm, from 1 mm to 2.5 mm, from 1 mm to 2 mm, or from 1 mm to 1.5 mm. In some embodiments, the film or sheet has a surface area of at least 25 mm2, such as a surface area of from 25 mm2to 1 m2.

[0017] In some embodiments, the array further comprises circuitry configured to store and / or transmit outputs from the plurality of magnetic force sensors. In some embodiments, the array further comprises memory for storing outputs from the plurality of magnetic force sensors. In some embodiments, the array further comprises hardware for wireless transmission of outputs from the plurality of magnetic force sensors.

[0018] In some embodiments, the array further includes a power supply configured to power the plurality of magnetic force sensors.

[0019] In some embodiments, each of the magnetic force sensors can comprise a magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and a spacer disposed between the magnetometer and the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator. In some embodiments, the magnetic actuator includes an elastomeric resin; and a population of magnetic particles dispersed within the elastomeric resin. In some embodiments, the spacer can be an elastomeric spacer.

[0020] In some embodiments, each of the magnetic force sensors includes a magnetic actuator having a proximal end and a distal end, the magnetic actuator including an elastomeric resin; and a population of magnetic particles dispersed within the elastomeric resin; a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and a spacer disposed between the magnetometer and the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator.

[0021] In some embodiments, each of the magnetic force sensors includes a magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in Attorney Docket No. 10776-035W01 proximity to the distal end of the magnetic actuator; and an elastomeric spacer disposed between the magnetometer and the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator.

[0022] In some embodiments, each of the magnetic force sensors can include a magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and an elastomeric housing enclosing at least a portion of the magnetic actuator and extending beyond the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator. In some embodiments, no elastomeric housing is disposed between the magnetometer and the distal end of the magnetic actuator.

[0023] In some embodiments, the magnetic actuator and the magnetometer can be sized relative to one another such that a force applied to the magnetic actuator in a x-y plane relative to the magnetometer, along a z-axis relative to the magnetometer, or any combination thereof produces a magnetic field response that is increasing and proportionate or decreasing and proportionate or decreasing and proportionate to the applied force.

[0024] In some embodiments, the magnetic actuator and the magnetometer can be sized relative to one another such that compression of the magnetic actuator under an applied force along the z-axis relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate or decreasing and proportionate to the applied force.

[0025] In some embodiments, the magnetic actuator and the magnetometer can be sized relative to one another such that shear of the magnetic actuator under an applied force in a x-y plane relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate or decreasing and proportionate to the applied force.

[0026] In some embodiments, each of the magnetic force sensors can include two or more magnetic actuators, each magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in proximity to the distal end of the one or more magnetic actuators; and a spacer disposed between the magnetometer and the distal end of the one or more magnetic actuators, thereby creating a standoff distance between the magnetometer and the distal end of the one or more magnetic actuators.

[0027] In some embodiments, the two or more magnetic actuators and the magnetometer are sized relative to one another such that a force applied to the two or more magnetic Attorney Docket No. 10776-035W01 actuators in a x-y plane relative to the magnetometer, along a z-axis relative to the magnetometer, or any combination thereof produces a magnetic field response that is increasing and proportionate or decreasing and proportionate or decreasing and proportionate to the applied force. In some embodiments, each of the magnetic actuators are adjacent to each other. In some embodiments, the magnetometer is operatively positioned in proximity to the distal end of the magnetic actuators. In some embodiments, the sensor further comprising a rigid spacer disposed between the magnetometer and the distal end of the two or more magnetic actuators, thereby creating a distance between the magnetometer and the distal end of the two or more magnetic actuators, wherein the rigid spacer is formed from a rigid material such as hard plastic, wood, glass, non-magnetic metal, or a material with a Shore A Hardness of greater than 70 and / or a Shore D Hardness of greater than 10.

[0028] It will be understood that embodiments employing a rigid spacer can be used, for example, for remote sensing, or sensing through a wall, or across empty air space. An example would be sensing through a protecting casing, where the magnetometer is outside the casing and the elastomeric portion of the sensor is inside the casing. In these examples, the wall of the casing can function as the rigid spacer. As such, the rigid spacer need not be exclusively part of the sensor. In some embodiments, a portion of the spacer can be a void space (e.g., an air space) as well.

[0029] In some embodiments, each of the magnetic force sensors can include a magnetic actuator, having a proximal end and a distal end; two or more magnetometers operatively positioned in proximity to the distal end of the magnetic actuator; and a spacer disposed between the two or more magnetometers and the distal end of the magnetic actuator, thereby creating a standoff distance between the one or more magnetometers and the distal end of the magnetic actuator.

[0030] In some embodiments, the magnetic actuator and the two or more magnetometers are sized relative to one another such that a force applied to the magnetic actuator in a x-y plane relative to the two or more magnetometers, along a z-axis relative to the two or more magnetometers, or any combination thereof produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force. In some embodiments, each of the magnetometers are adjacent to each other.

[0031] In some embodiments, the magnetic actuator can be a substantially circular horizontal cross-section, cylindrical shape or a substantially conical shape. In some embodiments, the standoff distance can be from greater than 0 mm to 5 mm. Attorney Docket No. 10776-035W01

[0032] In some embodiments, the spacer can be formed from an elastomeric resin, a rigid material, or any combination thereof. In some embodiments, when the spacer is formed from an elastomeric resin, the spacer includes a portion of a housing that partially or completely encloses the magnetic actuator. In some embodiments, the elastomeric spacer includes a portion of a housing that partially or completely encloses the magnetic actuator. In some embodiments, the elastomeric resin further comprises a non-magnetic filler, such as silica particles. In some embodiments, the sensor can further include a rigid spacer disposed between the magnetometer and the distal end of the elastomeric spacer, thereby creating a standoff distance between the magnetometer and the distal end of the elastomeric spacer, wherein the rigid spacer is formed from a rigid material such as hard plastic, wood, glass, non-magnetic metal, or a material with a Shore A Hardness of greater than 70 and / or a Shore D Hardness of greater than 10. In some other embodiments, the sensor further comprises a rigid spacer disposed between the magnetometer and the distal end of the elastomeric housing, thereby creating a standoff distance between the magnetometer and the distal end of the elastomeric housing, wherein the rigid spacer is formed from a rigid material such as hard plastic, wood, glass, non-magnetic metal, or a material with a shore hardness of greater than 70 A or greater than 10D.

[0033] In some embodiments, the magnetic particles comprise magnetic microparticles. In some embodiments, the magnetic microparticles have an average particle size of from 1 micron to 150 microns (e.g., 1 micron to 50 microns). In some embodiments, the magnetic particles comprise magnetic nanoparticles. In some embodiments, the magnetic nanoparticles have an average particle size of from 50 nm to less than 1 micron, such as from 50 nm to 500 nm. In some embodiments, the magnetic particles comprise anisotropic magnetic particles.

[0034] In some embodiments, the magnetic particles are present in the elastomeric resin in an amount of from 0.1% by weight to 90% by weight, based on the total weight of the elastomeric resin, such as from 50% by weight to 90% by weight, from 40% by weight to 80% by weight, from 30% to 70% by weight, from 20% to 60% by weight, from 15% to 50% by weight, from 0.1% to 50% by weight, from 0.1% to 40% by weight, from 0.1% to 30% by weight, from 0.1% to 20% by weight, from 0.1% by weight to 10% by weight, 0.1% by weight to 5% by weight, from 0.1% by weight to 2.5% by weight, or from 0.1% by weight to 1 % by weight, based on the total weight of the elastomeric resin. Attorney Docket No. 10776-035W01

[0035] In some embodiments, dipoles of the magnetic particles are aligned and / or oriented within the magnetic actuator. In some embodiments, dipoles of the magnetic particles are aligned and / or oriented within the magnetic actuator when the magnetic actuator is compressed by from 10% to 60% under an applied force.

[0036] In some embodiments, the sensor array further comprises a microcontroller, a processor, or a combination thereof operatively coupled to the magnetometer and configured to calculate a force applied to the magnetometer based on a measurement of a change in magnetic field strength.

[0037] In some embodiments, the magnetic actuator exhibits a Shore A Hardness within 25% (e.g., within 20%, within 15%, or within 10%) of a Shore A Hardness of the matrix.

[0038] In some embodiments, the sensor array further comprises an integrated motion sensor, such as a 9-axis inertial measurement unit.

[0039] Also provided herein are devices comprising the sensor arrays described herein. For example, provided herein is footwear (e.g., insoles) that comprise a sensor array described herein.

[0040] In some embodiments, the footwear includes a plurality of magnetic force sensors disposed in proximity to a wearer’s heel when the footwear is worn by a user. For example, in some embodiments, the footwear includes from 3 to 7 magnetic force sensors (e.g., in a cross-shaped pattern) disposed in proximity to the wearer’s heel when the footwear is worn by the user.

[0041] In some embodiments, the footwear includes a plurality of magnetic force sensors disposed in proximity to a ball of a wearer’ s foot when the footwear is worn by a user. For example, in some embodiments, the footwear includes from 2 to 8 magnetic force sensors (e.g., in rows) disposed in proximity to the ball of the wearer’s foot when the footwear is worn by the user.

[0042] Also provided herein are methods of using the sensor arrays described herein. By way of example, the footwear described herein can be used for the measurement of gait, for injury prevention, for physical therapy, for the improvement of gait, for the diagnosis or assessment of a neurological disorder or injury, or any combination thereof.

[0043] The details of one or more embodiments of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims. Attorney Docket No. 10776-035W01

[0044] DESCRIPTION OF DRAWINGS

[0045] FIGs. 1A-1B show a vertical cross section (FIG. 1 A) and horizontal cross section (FIG. IB) of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In this embodiment, the magnetic actuator (101) has a substantially cylindrical shape. In some embodiments, the plate (106) can be absent.

[0046] FIG. 2A-2B show a vertical cross section (FIG. 2A) and horizontal cross section (FIG 2B) of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In this embodiment, the magnetic actuator (101) has a substantially rectangular cuboid shape. In some embodiments, the plate (106) can be absent.

[0047] FIG. 3A-3B show a vertical cross section (FIG. 3A) and horizontal cross section (FIG 3B) of an example force sensor (100) including a magnetic actuator (101) having a Attorney Docket No. 10776-035W01 proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In this embodiment, the magnetic actuator (101) has a substantially conical shape. In some embodiments, the plate (106) can be absent.

[0048] FIG. 4A-4B show a vertical cross section (FIG. 4A) and horizontal cross section (FIG 4B) of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In this embodiment, the magnetic actuator (101) has a substantially spherical or ovoid shape. In some embodiments, the plate (106) can be absent.

[0049] FIG. 5 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal Attorney Docket No. 10776-035W01 end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In this embodiment, the largest cross-sectional dimension of the elastomeric housing (111) is larger than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In some embodiments, the plate (106) can be absent.

[0050] FIG. 6 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, the elastomeric housing (104) does not completely enclose the magnetic actuator (101). However, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In some embodiments, the plate (106) can be absent.

[0051] FIG. 7 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, the elastomeric housing (104) does not completely enclose the magnetic actuator (101). The elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), thereby creating a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this Attorney Docket No. 10776-035W01 embodiment, no elastomeric housing is disposed in a region (112) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In FIG. 7, the elastomeric housing (104) does not extend beyond and enclose the proximal end (107) of the magnetic actuator (101). However, it some embodiments, the elastomeric housing (104) extends beyond and encloses the proximal end (107) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In some embodiments, the plate (106) can be absent.

[0052] FIG. 8 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, an elastomeric spacer (105) is disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force.

[0053] FIG. 9 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a first portion (114) of a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The sensor further includes a rigid spacer (113) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101), such that the rigid spacer (113) creates a second portion (115) of a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). In this example, the largest cross-sectional dimension of the magnetic actuator (109) Attorney Docket No. 10776-035W01 is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In some embodiments, the plate (106) can be absent.

[0054] FIG. 10 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, two magnetometers (102A and 102B) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometers (102A and 102B) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102A and 102B) and the distal end (108) of the magnetic actuator (101). In some embodiments, the plate (106) can be absent. In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional distance (117) between the two magnetometers (102A and 102B) when the magnetic actuator (101) is not subjected to an applied force. Using this sensor, rotation can be measured based on the signal detected by the two magnetometers in the x-y axes.

[0055] FIG. 11 shows a vertical cross section of an example force sensor (100) including two magnetic actuators (101A and 101B) each having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the two magnetic actuators (101A and 101B), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuators, such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of two magnetic actuators (101A and 101B). The elastomeric spacer (105) creates a standoff distance (103) between the magnetometer (102) and the distal end (108) of two magnetic actuators (101A and 101B). In some embodiments, the plate (106) can be absent. In this example, the largest cross-sectional dimension of the magnetometer (110) is smaller than the largest cross-sectional distance (116) between the two magnetic actuators (101A and 101B) when the magnetic actuators are not subjected to an applied force. Using this sensor, location of a pinpoint force applied to the top surface of the elastomeric housing can be determined. Attorney Docket No. 10776-035W01

[0056] FIG. 12 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a first portion (114) of a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The sensor further includes a rigid spacer (113) disposed between the magnetometer (102) and the distal end (108) of the magnetic actuator (101), such that the rigid spacer (113) creates a second portion (115) of a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The sensor further includes a gap (119) between the magnetometer (102) and the rigid spacer (113), such that the gap (119) creates a third portion (118) of a standoff distance (103) between the magnetometer (102) and the distal end (108) of the magnetic actuator (101). The gap (119) may be a void (e.g., an airspace), or may be filled with any other material, such as a fabric. In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In some embodiments, the plate (106) can be absent.

[0057] FIG. 13 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned substantially adjacent to and parallel with the magnetic actuator (101), and a plate (106). In this example, a portion of the elastomeric housing (104) extends beyond the distal end (108) of the magnetic actuator (101), such that a portion of the elastomeric housing forms an elastomeric spacer (105) disposed between the plate (106) and the distal end (108) of the magnetic actuator (101). The elastomeric spacer (105) creates a standoff distance (103) between the plate (106) and the distal end (108) of the magnetic actuator (101).

[0058] FIG. 14 shows a vertical cross section of an example force sensor (100) including a magnetic actuator (101) having a proximal end (107) and a distal end (108), an elastomeric Attorney Docket No. 10776-035W01 housing (104) formed from an elastomeric resin, a magnetometer (102) operatively positioned in proximity to the distal end (108) of the magnetic actuator (101), and a plate (106). In this example, the magnetic actuator (101) abuts the magnetometer (102) (i.e., there is no standoff distance between the magnetometer (102) and the distal end (108) of the magnetic actuator (101)). In this example, the largest cross-sectional dimension of the magnetic actuator (109) is smaller than the largest cross-sectional dimension of the magnetometer (110) when the magnetic actuator (101) is not subjected to an applied force. In some embodiments, the plate (106) can be absent.

[0059] FIG. 15A shows an image of a flat flexible magnetometer circuit and controller chip. FIG. 15B shows an image of a sensor formed by combining the silicone sensor component (magnetic actuator enclosed in an elastomeric hosing) with the flat flexible magnetometer circuit.

[0060] FIG. 15C is a plot showing the magnetic field response vs. time during several repeated stepwise 1 mm compression cycles performed on a sensor using the flat flexible magnetometer circuit.

[0061] FIG. 16 includes images of the qualitative silicone -based adhesive bonding tests (top left and top right), and an image of the three sensors that were constructed using the three different silicone-based adhesives (SILPOXY, MED4-4220, and MED3-4013) to adhere the silicone sensor component (magnetic actuator enclosed in an elastomeric hosing) to the magnetometer circuit board. All three of these adhesives were found to have sufficient bonding strength to join the silicone sensor component to the magnetometer circuit board.

[0062] FIG. 17 is a plot showing magnetic field response vs. time during the 1 mm stepwise compression test for sensor formed by combining the silicone sensor component with the flat flexible magnetometer circuit using various silicone-based adhesives.

[0063] FIG. 18 is a three-dimensional rendering of an example flat flexible magnetometer circuit and controller chip.

[0064] FIG. 19 illustrates an example insole containing a sensor array in different stages of its manufacturing process. A) Silicone insole with magnets and internal circuitry. B) Men’s size 11 / 12 left insole and a Women’s size 5 / 6 right insole in the finished stage before inserting into the shoe. C) Example insole inserted into a standard athletic shoe.

[0065] FIG. 20 illustrates the external validation testing performed on the insoles. A) Men’s size 12 insole testing atop a 3D force plate. B) Ground Truth vs. Predicted ground reaction forces presented for the X, Y, and Z axes (from left to right respectively) for all 13 Attorney Docket No. 10776-035W01 movements for same insole. Blue dots represent each point predicted by the model and red line represents a perfect prediction.

[0066] FIG. 21 shows representative time series ground reaction forces in the X, Y, and Z axes (from top to bottom respectively) for a representative insole validation data set. The red trace represents the predicted force from the example insoles, and the blue tract represents the ground truth measured by the force plate

[0067] FIG. 22 shows an example sensor array integrated within a helmet.

[0068] FIG. 23 shows an example sensor array disposed within a cushion in a rocket.

[0069] FIG. 24 shows an example sensor array disposed within a glove.

[0070] FIG. 25A shows an example sensor array disposed within a prosthetic liner.

[0071] FIG. 25B is a demonstration of a smart prosthetic liner prototype device shown in FIG. 25A. The prototype had multiple sensors embedded seamlessly within the liner and sensor customization and proper material selection allowed for the mechanical properties of the sensors to match the mechanical properties of the rest of the liner. This figure shows forces being applied to one of the sensors in the prototype, and the data from the demonstration plotted via software. All sensors were capable of reporting 3-axis forces in real time within the liner.

[0072] FIG. 26A shows an example sensor array disposed within a 3D force plate.

[0073] FIG. 26B - FIG. 26E illustrate that sensor embedded load cells, and devices constructed with such load cells are capable of extremely high levels of accuracy in comparison to typical gold standard force measurement systems. FIG. 26B shows the performance (force measurement) of an example load cell described herein vs. a reference load cell during validation testing in the X-axis (Fx), Y-axis (Fy), and Z-axis (Fz) from left to right. FIG. 26C shows the performance (force measurement) of an example force plate described herein vs. a reference force plate during validation testing in the X-axis (Fx), Y- axis (Fy), and Z-axis (Fz) from left to right. FIG. 26D shows the performance (moments) of an example force plate described herein vs. a reference force plate during validation testing in the X-axis (Mx), Y-axis (My), and Z-axis (Mz) from left to right. FIG. 26E shows force vs. time plots for the X-axis (Fx), Y-axis (Fy), and Z-axis (Fz) from top to bottom from a human countermovement jump collected atop an example force plate described herein in series with a reference force plate.

[0074] Like reference symbols in the various drawings indicate like elements. Attorney Docket No. 10776-035W01

[0075] DETAILED DESCRIPTION

[0076] A number of embodiments of the disclosure have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

[0077] Definitions

[0078] To facilitate understanding of the disclosure set forth herein, a number of terms are defined below. Unless defined otherwise, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference.

[0079] General Definitions

[0080] The term “comprising” and variations thereof as used herein is used synonymously with the term “including” and variations thereof and are open, non-limiting terms. Although the terms “comprising” and “including” have been used herein to describe various embodiments, the terms “consisting essentially of” and “consisting of’ can be used in place of “comprising” and “including” to provide for more specific embodiments of the invention and are also disclosed. Other than where noted, all numbers expressing quantities of ingredients, reaction conditions, geometries, dimensions, and so forth used in the specification and claims are to be understood at the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, to be construed in light of the number of significant digits and ordinary rounding approaches.

[0081] As used in this specification and the following claims, the terms “comprise” (as well as forms, derivatives, or variations thereof, such as “comprising” and “comprises”) and “include” (as well as forms, derivatives, or variations thereof, such as “including” and “includes”) are inclusive (i.e., open-ended) and do not exclude additional elements or steps. For example, the terms "comprise" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Accordingly, these terms are intended to not only cover the recited element(s) or step(s), but may also include other elements or steps not expressly recited. Furthermore, as used herein, the use of the terms “a”, “an”, and “the” when used in conjunction with an Attorney Docket No. 10776-035W01 element may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” Therefore, an element preceded by “a” or “an” does not, without more constraints, preclude the existence of additional identical elements.

[0082] The use of the term “about” applies to all numeric values, whether or not explicitly indicated. This term generally refers to a range of numbers that one of ordinary skill in the art would consider as a reasonable amount of deviation to the recited numeric values (i.e., having the equivalent function or result). For example, this term can be construed as including a deviation of ±10 percent of the given numeric value provided such a deviation does not alter the end function or result of the value. Therefore, a value of about 1 % can be construed to be a range from 0.9% to 1.1 %. Furthermore, a range may be construed to include the start and the end of the range. For example, a range of 10% to 20% (i.e., range of 10%-20%) can includes 10% and also includes 20%, and includes percentages in between 10% and 20%, unless explicitly stated otherwise herein.

[0083] It is understood that when combinations, subsets, groups, etc. of elements are disclosed (e.g., combinations of components in a composition, or combinations of steps in a method), that while specific reference of each of the various individual and collective combinations and permutations of these elements may not be explicitly disclosed, each is specifically contemplated and described herein.

[0084] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. By “about” is meant within 5% of the value, e.g., within 4, 3, 2, or 1% of the value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed.

[0085] As used herein, the terms "may," "optionally," and "may optionally" are used interchangeably and are meant to include cases in which the condition occurs as well as cases in which the condition does not occur. Thus, for example, the statement that a Attorney Docket No. 10776-035W01 formulation "may include an excipient" is meant to include cases in which the formulation includes an excipient as well as cases in which the formulation does not include an excipient.

[0086] By way of non-limiting illustration, examples of certain embodiments of the present disclosure are given below.

[0087] Magnetic Sensor Arrays

[0088] Described herein magnetic sensor array that comprise a plurality of magnetic force sensors disposed in relative position with respect to one another within a matrix. In some embodiments, the plurality of magnetic force sensors can be integrated within the matrix at relative positions with respect to one another to create a 2-dimensional or 3 -dimensional array of sensors within the matrix. Magnetic sensor array can then measure forces acting on the matrix. When integrated within a device or deployed on a surface, the sensor array can efficiently measure forces acting on the device or surface. Likewise, when worn by a user, the sensor can efficiently measure forces acting on the user. The sensor arrays described herein can find use in a wide range of applications, as described in more detail below.

[0089] In some embodiments, the matrix comprises an elastomeric matrix. In certain embodiments, the elastomeric matrix comprises a crosslinkable composition, such as a crosslinkable silicone composition.

[0090] In some embodiments, the magnetic sensor array comprises from 2 to 50 magnetic force sensors, such as from 5 to 50 magnetic force sensors, from 5 to 40 magnetic force sensors, from 5 to 30 magnetic force sensors, from 5 to 25 magnetic force sensors, from 5 to 20 magnetic force sensors, from 5 to 15 magnetic force sensors, from 8 to 50 magnetic force sensors, from 8 to 40 magnetic force sensors, from 8 to 30 magnetic force sensors, from 8 to 25 magnetic force sensors, from 8 to 20 magnetic force sensors, or from 8 to 15 magnetic force sensors.

[0091] In some embodiments, the magnetic force sensors in the magnetic sensor array are separated from their nearest neighboring magnetic force sensor by a minimum distance of at least 5 mm, such as at least 10 mm, at least 15 mm, at least 20 mm, at least 25 mm, at least 30 mm, at least 35 mm, at least 40 mm, at least 45 mm, or at least 50 mm.

[0092] In some embodiments, the matrix comprises a film or sheet. In some embodiments, the film or sheet has a thickness of less than 10 mm, such as a thickness of less than 9.5 mm, less than 9 mm, less than 8.5 mm, less than 8 mm, less than 7.5 mm, less than 7 mm, Attorney Docket No. 10776-035W01 less than 6.5 mm, less than 6 mm, less than 5.5 mm, less than 5 mm, less than 4.5 mm, less than 4 mm, less than 3.5 mm, less than 3 mm, less than 2.5 mm, less than 2 mm, or less than 1.5 mm. In certain examples, the film or sheet has a thickness of from 0.5 mm to 7.5 mm, such as a thickness of from 0.5 mm to 7 mm, from 0.5 mm to 6.5 mm, from 0.5 mm to 6 mm, from 0.5 mm to 5.5 mm, from 0.5 mm to 5 mm, from 0.5 mm to 4.5 mm, from 0.5 mm to 4 mm, from 0.5 mm to 3.5 mm, from 0.5 mm to 3 mm, from 0.5 mm to 2.5 mm, from 0.5 mm to 2 mm, from 0.5 mm to 1.5 mm, from 0.75 mm to 7.5 mm, from 0.75 mm to 7 mm, from 0.75 mm to 6.5 mm, from 0.75 mm to 6 mm, from 0.75 mm to 5.5 mm, from 0.75 mm to 5 mm, from 0.75 mm to 4.5 mm, from 0.75 mm to 4 mm, from 0.75 mm to 3.5 mm, from 0.75 mm to 3 mm, from 0.75 mm to 2.5 mm, from 0.75 mm to 2 mm, from 0.75 mm to 1.5 mm, from 1 mm to 7.5 mm, from 1 mm to 7 mm, from 1 mm to 6.5 mm, from 1 mm to 6 mm, from 1 mm to 5.5 mm, from 1 mm to 5 mm, from 1 mm to 4.5 mm, from 1 mm to 4 mm, from 1 mm to 3.5 mm, from 1 mm to 3 mm, from 1 mm to 2.5 mm, from 1 mm to 2 mm, or from 1 mm to 1.5 mm. In some embodiments, the film or sheet has a surface area of at least 25 mm2, such as a surface area of from 25 mm2to 1 m2.

[0093] In some embodiments, the array further comprises circuitry configured to store and / or transmit outputs from the plurality of magnetic force sensors. In some embodiments, the array further comprises memory for storing outputs from the plurality of magnetic force sensors. In some embodiments, the array further comprises hardware for wireless transmission of outputs from the plurality of magnetic force sensors.

[0094] In some embodiments, the array further includes a power supply configured to power the plurality of magnetic force sensors.

[0095] In some embodiments, the sensor array further comprises a microcontroller, a processor, or a combination thereof operatively coupled to the magnetometer and configured to calculate a force applied to the magnetometer based on a measurement of a change in magnetic field strength.

[0096] In some embodiments, the magnetic actuator exhibits a Shore A Hardness within 25% (e.g., within 20%, within 15%, or within 10%) of a Shore A Hardness of the matrix.

[0097] In some embodiments, the sensor array further comprises an integrated motion sensor, such as a 9-axis inertial measurement unit.

[0098] Also provided herein are devices comprising the sensor arrays described herein. For example, provided herein is footwear (e.g., insoles) that comprise a sensor array described herein. Attorney Docket No. 10776-035W01

[0099] In some embodiments, the footwear includes a plurality of magnetic force sensors disposed in proximity to a wearer’s heel when the footwear is worn by a user. For example, in some embodiments, the footwear includes from 3 to 7 magnetic force sensors (e.g., in a cross-shaped pattern) disposed in proximity to the wearer’s heel when the footwear is worn by the user.

[0100] In some embodiments, the footwear includes a plurality of magnetic force sensors disposed in proximity to a ball of a wearer’ s foot when the footwear is worn by a user. For example, in some embodiments, the footwear includes from 2 to 8 magnetic force sensors (e.g., in rows) disposed in proximity to the ball of the wearer’s foot when the footwear is worn by the user.

[0101] Also provided herein are methods of using the sensor arrays described herein. By way of example, the footwear described herein can be used for the measurement of gait, for injury prevention, for physical therapy, for the improvement of gait, for the diagnosis or assessment of a neurological disorder or injury, or any combination thereof.

[0102] Magnetic Force Sensors

[0103] Magnetic force sensors that can be incorporated in the force sensor arrays described herein include those described in International Publication No. WO 2022 / 256326, which is incorporated herein by reference in its entirety. Example force sensors are illustrated in FIGs. 1A-18, which are described in the Description of Drawings above.

[0104] Briefly, in some embodiments, magnetic force sensor can comprise a magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and a spacer disposed between the magnetometer and the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator. In some embodiments, the magnetic actuator includes an elastomeric resin; and a population of magnetic particles dispersed within the elastomeric resin. In some embodiments, the spacer can be an elastomeric spacer.

[0105] In some embodiments, the force sensor includes a magnetic actuator having a proximal end and a distal end, the magnetic actuator including an elastomeric resin; and a population of magnetic particles dispersed within the elastomeric resin; a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and a spacer disposed between the magnetometer and the distal end of the magnetic actuator, thereby Attorney Docket No. 10776-035W01 creating a standoff distance between the magnetometer and the distal end of the magnetic actuator.

[0106] In some embodiments, the force sensor includes a magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and an elastomeric spacer disposed between the magnetometer and the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator.

[0107] In some embodiments, the force sensor can include a magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and an elastomeric housing enclosing at least a portion of the magnetic actuator and extending beyond the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator. In some embodiments, no elastomeric housing is disposed between the magnetometer and the distal end of the magnetic actuator.

[0108] In some embodiments, the magnetic actuator and the magnetometer can be sized relative to one another such that a force applied to the magnetic actuator in a x-y plane relative to the magnetometer, along a z-axis relative to the magnetometer, or any combination thereof produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force.

[0109] In some embodiments, the magnetic actuator and the magnetometer can be sized relative to one another such that compression of the magnetic actuator under an applied force along the z-axis relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force.

[0110] In some embodiments, the force sensor can include two or more magnetic actuators, each magnetic actuator having a proximal end and a distal end; a magnetometer operatively positioned in proximity to the distal end of the one or more magnetic actuators; and a spacer disposed between the magnetometer and the distal end of the one or more magnetic actuators, thereby creating a standoff distance between the magnetometer and the distal end of the one or more magnetic actuators.

[0111] In some embodiments, the two or more magnetic actuators and the magnetometer are sized relative to one another such that a force applied to the two or more magnetic actuators in a x-y plane relative to the magnetometer, along a z-axis relative to the magnetometer, or any combination thereof produces a magnetic field response that is Attorney Docket No. 10776-035W01 increasing and proportionate or decreasing and proportionate to the applied force. In some embodiments, each of the magnetic actuators are adjacent to each other. In some embodiments, the magnetometer is operatively positioned in proximity to the distal end of the magnetic actuators. In some embodiments, the sensor further comprising a rigid spacer disposed between the magnetometer and the distal end of the two or more magnetic actuators, thereby creating a distance between the magnetometer and the distal end of the two or more magnetic actuators, wherein the rigid spacer is formed from a rigid material such as hard plastic, wood, glass, non-magnetic metal, or a material with a Shore A Hardness of greater than 70 and / or a Shore D Hardness of greater than 10.

[0112] In some embodiments, the force sensor can include a magnetic actuator, having a proximal end and a distal end; two or more magnetometers operatively positioned in proximity to the distal end of the magnetic actuator; and a spacer disposed between the two or more magnetometers and the distal end of the magnetic actuator, thereby creating a standoff distance between the one or more magnetometers and the distal end of the magnetic actuator.

[0113] In some embodiments, the magnetic actuator and the two or more magnetometers are sized relative to one another such that a force applied to the magnetic actuator in a x-y plane relative to the two or more magnetometers, along a z-axis relative to the two or more magnetometers, or any combination thereof produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force. In some embodiments, each of the magnetometers are adjacent to each other.

[0114] In some embodiments, the magnetic field response can increase 5-20% less than the increase proportionate to the applied force.

[0115] In some embodiments, the magnetic actuator can have a largest cross-sectional dimension that is smaller than a largest cross-sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force. The largest cross-sectional dimension of the magnetic actuator can be from 5% to 80% of the largest cross-sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force. In some embodiments, the magnetic actuator can have a largest cross-sectional dimension that is smaller than a largest cross-sectional dimension of the magnetometer when the magnetic actuator is compressed by 40% under an applied force. In some embodiments, the largest cross-sectional dimension of the magnetic actuator can be from Attorney Docket No. 10776-035W01

[0116] 50% to 90% of the largest cross-sectional dimension of the magnetometer when the magnetic actuator is compressed by 40% under an applied force.

[0117] In some embodiments, the magnetic actuator can have a largest cross-sectional area that is smaller than a largest cross-sectional area of the magnetometer when the magnetic actuator is not subjected to an applied force. The largest cross-sectional area of the magnetic actuator can be from 50% to 90% of the largest cross-sectional are of the magnetometer when the magnetic actuator is not subjected to an applied force. In some embodiments, the magnetic actuator has a largest cross-sectional area that is smaller than a largest cross- sectional area of the magnetometer when the magnetic actuator is compressed by 40% under an applied force. In some embodiments, the largest cross-sectional area of the magnetic actuator is from 50% to 90% of the largest cross-sectional area of the magnetometer when the magnetic actuator is compressed by 40% under an applied force.

[0118] In some embodiments, the magnetic actuator and the magnetometer are sized relative to one another such that compression of the magnetic actuator under a window of applied forces ranging from an applied force effective to compress the magnetic actuator by 5% to an applied force effective to compress the magnetic actuator by 40% produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force across the window of applied forces. In some embodiments, the magnetic actuator and the magnetometer are sized relative to one another such that compression of the magnetic actuator under a window of applied forces ranging from an applied force effective to compress the magnetic actuator by 3% to an applied force effective to compress the magnetic actuator by 20% produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force across the window of applied forces.

[0119] In some embodiments, a force applied to the magnetic actuator in the x-y plane relative to the magnetometer produces a magnetic field response that is increasing and linear relative to the applied force. In some embodiments, a force applied to the magnetic actuator along the z-axis relative to the magnetometer produces a magnetic field response that is increasing and linear relative to the applied force. In some embodiments, a force applied to the magnetic actuator in the x-y plane relative to the magnetometer produces a magnetic field response that is increasing and linear relative to the applied force and a force applied to the magnetic actuator along the z-axis relative to the magnetometer produces a magnetic field response that is increasing and linear relative to the applied force. Attorney Docket No. 10776-035W01

[0120] In some embodiments, the magnetic actuator and the magnetometer can be sized relative to one another such that shear of the magnetic actuator under an applied force in a x-y plane relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force. The magnetic actuator can have a largest cross-sectional dimension that is smaller than a largest cross- sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force. In some embodiments, the largest cross-sectional dimension of the magnetic actuator can be from 5% to 80% of the largest cross-sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force. In some embodiments, the magnetic actuator can have a largest cross-sectional dimension that is smaller than a largest cross-sectional dimension of the magnetometer when the magnetic actuator is sheared by 40% under an applied force. In some embodiments, the largest cross- sectional dimension of the magnetic actuator can be from 50% to 90% of the largest cross- sectional dimension of the magnetometer when the magnetic actuator is sheared by 40% under an applied force.

[0121] In some embodiments, the magnetic actuator can have a largest cross-sectional area that is smaller than a largest cross-sectional area of the magnetometer when the magnetic actuator is not subjected to an applied force. The largest cross-sectional area of the magnetic actuator can be from 50% to 90% of the largest cross-sectional are of the magnetometer when the magnetic actuator is not subjected to an applied force. In some embodiments, the magnetic actuator has a largest cross-sectional area that is smaller than a largest cross- sectional area of the magnetometer when the magnetic actuator is sheared by 40% under an applied force. In some embodiments, the largest cross-sectional area of the magnetic actuator is from 50% to 90% of the largest cross-sectional area of the magnetometer when the magnetic actuator is sheared by 40% under an applied force.

[0122] In some embodiments, the magnetic actuator and the magnetometer are sized relative to one another such that shear of the magnetic actuator under a window of applied forces ranging from an applied force effective to induce a shear strain of the magnetic actuator by 5% to an applied force effective to induce a shear strain of the magnetic actuator by 40% produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force across the window of applied forces. In some embodiments, the magnetic actuator and the magnetometer are sized relative to one another such that shear of the magnetic actuator under a window of applied forces ranging Attorney Docket No. 10776-035W01 from an applied force effective to induce a shear strain of the magnetic actuator by 3% to an applied force effective to induce a shear strain of the magnetic actuator by 20% produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force across the window of applied forces.

[0123] In some embodiments, the magnetic actuator can have a largest cross-sectional dimension of from 1 mm to 25 mm. For example, from 1 mm to 5 mm, from 1 mm to 10 mm, from 1 mm to 15 mm, from 1 mm to 20 mm, from 5 mm to 20 mm, from 5 mm to 15 mm, from 10 mm to 25 mm, or from 10 mm to 20 mm.

[0124] In some embodiments, the magnetic actuator can be a substantially circular horizontal cross-section, cylindrical shape or a substantially conical shape. In some embodiments, the magnetic actuator has a substantially circular horizontal cross-section. In some embodiments, the magnetic actuator has a substantially cylindrical shape. In some embodiments, the magnetic actuator has a substantially conical shape.

[0125] In some embodiments, the standoff distance can be from greater than 0 mm to 5 mm, such as from greater than 0 mm to 1.5 mm, greater than 0 mm to 3 mm, greater than 1 mm to 5 mm, greater than 1 to 3 mm, or greater than 2 mm to 5 mm. In some embodiments, the standoff distance can be selected to provide a measurable signal such as magnetic field response greater than 100 pT with an applied force. In some embodiments there may be no standoff distance.

[0126] In some embodiments, the spacer can be formed from an elastomeric resin, a rigid material, or any combination thereof. In some embodiments, the spacer can be formed from an elastomeric resin. In some embodiments, the spacer can be an elastomeric spacer.

[0127] In some embodiments, the elastomeric housing is formed from an elastomeric resin. In some embodiments, the elastomeric spacer can be formed from an elastomeric resin.

[0128] In some embodiments, the spacer can be formed from a rigid material. In some embodiments, when the spacer is formed from an elastomeric resin, the spacer includes a portion of a housing that partially or completely encloses the magnetic actuator. In some embodiments, the elastomeric spacer includes a portion of a housing that partially or completely encloses the magnetic actuator.

[0129] In some embodiments, the elastomeric resin further comprises a non-magnetic filler, such as silica particles. In some embodiments, the elastomeric resin comprises a crosslinkable composition, such as a crosslinkable silicone composition. In some embodiments, the elastomeric resin comprises (A) a first organosilicon compound having at Attorney Docket No. 10776-035W01 least two ethylenically unsaturated moieties per molecule; and optionally (B) one or more additional organosilicon compounds. In some embodiments, the sensor can further include a rigid spacer disposed between the magnetometer and the distal end of the elastomeric spacer, thereby creating a standoff distance between the magnetometer and the distal end of the elastomeric spacer, wherein the rigid spacer is formed from a rigid material such as hard plastic, wood, glass, non-magnetic metal, or a material with a Shore A Hardness of greater than 70 and / or a Shore D Hardness of greater than 10. In some other embodiments, the sensor further comprises a rigid spacer disposed between the magnetometer and the distal end of the elastomeric housing, thereby creating a standoff distance between the magnetometer and the distal end of the elastomeric housing, wherein the rigid spacer is formed from a rigid material such as hard plastic, wood, glass, non-magnetic metal, or a material with a shore hardness of greater than 70 A or greater than 10D.

[0130] In some embodiments, the sensor further comprises a microcontroller, a processor, or a combination thereof operatively coupled to the magnetometer and configured to calculate a force applied to the magnetometer based on a measurement of a change in magnetic field strength.

[0131] Composites Forming the Magnetic Actuator

[0132] As discussed above, the magnetic actuator can be formed of a composite that comprises an elastomeric resin; and a population of magnetic particles (e.g., anisotropic magnetic particles) dispersed within the elastomeric resin.

[0133] Magnetic particles

[0134] The magnetic particles can be any suitable magnetic particles.

[0135] In some embodiments, the magnetic particles comprise magnetic microparticles. The microparticles can be of any shape, and have one or more dimensions ranging from 1 micron to 150 microns (e.g., from 1 micron to 100 microns, or from 1 micron to 50 microns). In some embodiments, all dimensions can range from 1 micron to 150 microns (e.g., from 1 micron to 100 microns, or from 1 micron to 50 microns).

[0136] In some embodiments, the magnetic particles can comprise nanoparticles. The term “nanoparticle,” as used herein, generally refers to a particle of any shape having one or more dimensions ranging from 1 nm up to, but not including, 1 micron.

[0137] In some embodiments, the population of magnetic particles are a monodisperse population of magnetic particles. In other embodiments, the population of magnetic particles are a polydisperse population of anisotropic magnetic particles. In some instances Attorney Docket No. 10776-035W01 where the population of magnetic particles is polydisperse, greater that 50% of the particle size distribution, more preferably 60% of the particle size distribution, most preferably 75% of the particle size distribution lies within 10% of the median particle size.

[0138] The magnetic particles can comprise any suitable magnetic material, such as ferromagnetic alloys comprising Fe, Nd, Co, Ni, or combinations thereof. In certain embodiments, the magnetic particles can comprise Ni particles. In some embodiments, the magnetic particles can comprise spherical (or substantially spherical) magnetic particles. In some embodiments, the magnetic particles can comprise cubic magnetic particles. In other embodiments, the magnetic particles can comprise anisotropic magnetic particles. Such particles can be formed using methods known in the art, including synthesis driven by appropriate shaping ligands, template-assisted synthesis, template- as sis ted electrodeposition, and magnetically directed assembly. Examples of such materials are described, for example, in Lisjak et al. “Anisotropic Magnetic Nanoparticles: A Review of their Properties, Synthesis, and Potential Applications,” Progress in Materials Science, 2018, 95; 286-328 (which is hereby incorporated by reference in its entirety for its description of anisotropic magnetic particles, and which is attached to this filing).

[0139] The magnetic particles can be essentially homogeneous throughout, meaning that the composition does not vary throughout the particle cross-section (from the particle surface to the particle center). Alternatively, the magnetic particles can possess a non- homogeneous structure. For example, the particles may possess a core-shell structure, or a multilayer structure (e.g., a magnetic core coated by a non-magnetic shell material).

[0140] The magnetic particles may have any desired shape. In certain embodiments, the particles can have a non-spherical shape. As generally used herein, “non-spherical” is used to describe particles having at least one dimension differing from another dimension by a ratio of at least 1 :1.10. In one embodiment, the non-spherical particles have at least one dimension which differs from another dimension by a ratio of at least 1 : 1.25. A wide variety of shapes are considered “non-spherical” shapes. For example, non-spherical particles may be in the shape of rectangular disks, high aspect ratio rectangular disks, rods, high aspect ratio rods, worms, oblate ellipses, prolate ellipses, elliptical disks, UFOs, circular disks, barrels, bullets, pills, pulleys, bi-convex lenses, ribbons, ravioli, flat pill, bicones, diamond disks, emarginated disks, elongated hexagonal disks, tacos, wrinkled prolate ellipsoids, wrinkled oblate ellipsoids, or porous elliptical disks. Additional shapes beyond those Attorney Docket No. 10776-035W01 illustrated in the figures are also within the scope of the definition for “non-spherical” shapes.

[0141] In some embodiments, the magnetic particles can comprise rod-shaped particles. “Rod-shaped,” as used herein, refers to a particle which has an elongated spherical or cylindrical shape (e.g., the shape of a pill) or a flattened rod-shape, such as the shape of a green bean. Rod-shaped particles have an aspect ratio of at least 1.25 (e.g., at least 1.5, at least 2, at least 2.5, or at least 5). “Aspect ratio,” as used herein, refers to the length divided by the diameter of a particle.

[0142] In certain embodiments, the particles can be rod-shaped. In some embodiments, the rod-shaped particles can have an aspect ratio, defined as the length of the rod-shaped particle divided by the diameter of the rod-shaped particle, of at least 1.25 (e.g., at least 2.5, at least 5, at least 10, at least 15, at least 25, at least 50, at least 100, at least 150, at least 200, at least 250, or more). In some embodiments, the rod-shaped particles can have an aspect ratio, defined as the length of the rod-shaped particle divided by the diameter of the rod-shaped particle, of 500 or less (e.g., 250 or less, 200 or less, 150 or less, 100 or less, 50 or less, 25 or less, 15 or less, 10 or less, 5 or less, or 2.5 or less).

[0143] The rod-shaped particles can have an aspect ratio ranging from any of the minimum values described above to any of the maximum values described above. In certain embodiments, the rod-shaped particles can have an aspect ratio of from 1.25 to 500 (e.g., from 5 to 500, from 5 to 250, from 5 to 100, from 5 to 500, from 5 to 250, or from 5 to 100).

[0144] In some embodiments, the rod-shaped particles can have an average diameter of at least 5 nm (e.g., at least 25 nm, at least 50 nm, at least 100 nm, at least 200 nm, at least 300 nm, at least 400 nm, at least 500, at least 600 nm, at least 700 nm, at least 800 nm, or at least 900 nm). In some embodiments, the rod-shaped particles can have an average diameter of 950 nm or less (e.g., 900 nm or less, 800 nm or less, 700 nm or less, 600 nm or less, 500 nm or less, 400 nm or less, 300 nm or less, 200 nm or less, 100 nm or less, 50 nm or less, or 25 nm or less.

[0145] The rod-shaped particles can have an average diameter ranging from any of the minimum values described above to any of the maximum values described above. In certain embodiments, the rod-shaped particles can have an average diameter of from 50 nm to 800 nm (e.g., from 50 nm to 500 nm, or from 100 nm to 300 nm).

[0146] In some embodiments, the rod-shaped particles can have an average length of at least 500 nm (e.g., at least 1 micron, at least 5 microns, at least 10 microns, at least 15 Attorney Docket No. 10776-035W01 microns, at least 20 microns, at least 25 microns, at least 50 microns, at least 75 microns, at least 100 microns, at least 150 microns, or at least 200 microns). In some embodiments, the rod-shaped particles can have an average length of 250 microns or less (e.g., 200 microns or less, 150 microns or less, 100 microns or less, 75 microns or less, 50 microns or less, 25 microns or less, 20 microns or less, 15 microns or less, 10 microns or less, 5 microns or less, or 1 micron or less).

[0147] The rod-shaped particles can have an average length ranging from any of the minimum values described above to any of the maximum values described above. In certain embodiments, the rod-shaped particles can have an average length of from 500 nm to 100 microns (e.g., from 1 micron to 25 microns).

[0148] In some embodiments, the magnetic particles can comprise anisotropic magnetic particles. In some embodiments, dipoles of the magnetic particles are aligned and / or oriented within the magnetic actuator. In some embodiments, dipoles of the magnetic particles are aligned and / or oriented within the magnetic actuator when the magnetic actuator is compressed by from 10% to 60% under an applied force.

[0149] The magnetic particles can be present in the composition in an amount of from 0.1% by weight to 90% by weight, based on the total weight of the elastomeric resin, such as from 50% by weight to 90% by weight, from 40% by weight to 80% by weight, from 30% to 70% by weight, from 20% to 60% by weight, from 15% to 50% by weight, from 0.1% to 50% by weight, from 0.1% to 40% by weight, from 0.1% to 30% by weight, from 0.1% to 20% by weight, from 0.1% by weight to 10% by weight, 0.1 % by weight to 5% by weight, from 0.1% by weight to 2.5% by weight, or from 0.1% by weight to 1% by weight, based on the total weight of the elastomeric resin.

[0150] The magnetic particles can be present in the composition in an amount of from 0.01% by volume to 20% by volume (e.g., from 0.01% by volume to 15% by volume, from 0.01 % by volume to 10% by volume, from 0.01% by volume to 7.5% by volume, from 0.01% by volume to 5% by volume, from 0.01% by volume to 2.5% by volume, or from 0.01% by volume to 1% by volume), based on the total volume of the composition.

[0151] In some embodiments, the magnetic particles can be uniformly dispersed throughout the elastomeric resin. In other embodiments, the magnetic particles can by non- homogenously dispersed throughout the elastomeric resin. For example, the magnetic particles can be at varying concentrations throughout the elastomeric resin (e.g., at a higher concentration at a region in proximity to a magnetometer and at a lower concentration at a Attorney Docket No. 10776-035W01 region further away from a magnetometer). In some embodiments, a gradient of magnetic particles can be dispersed within the elastomeric resin.

[0152] Elastomeric Resins

[0153] The elastomeric resin can comprise an elastomeric resin suitable for use in an additive manufacturing process. Such materials are well known in the art. In some examples, the elastomeric resin can comprise a thermoplastic polymer such as acrylonitrile butadiene styrene (ABS), polyphenylene sulfide (PPS), polyphenylsulfone (PPSU), polyetheretherketone (PEEK), polyurethane (PU), polyetherimide (PEI), polyphenylene ether (PPE), polycarbonate (PC), and combinations thereof. In some embodiments, the elastomeric resin can comprise a crosslinkable composition (e.g., a blend of monomers, oligomers, and / or polymers which can be crosslinked during the additive manufacturing process). Depending on the additive manufacturing process employed, the crosslinkable composition can be selected such that crosslinking can be induced thermally and / or by impinging electromagnetic radiation (e.g., UV and / or visible light). In certain embodiments, the elastomeric resin can comprise a crosslinkable silicone composition. For example, the elastomeric resin can comprise (A) a first organosilicon compound having at least two ethylenically unsaturated moieties per molecule; and optionally (B) one or more additional organosilicon compounds. Suitable silicone compositions are known in the art. See, for example, U.S. Patent No. 10,155,884 to Dow Silicones Corp., U.S. Patent Application Publication No. 2017 / 0312981 to Wacker Chemie AG, U.S. Patent Application Publication No. 2018 / 0370141 to Wacker Chemie AG, U.S. Patent Application Publication No. 2018 / 0066115 to Wacker Chemie AG, U.S. Patent Application Publication No. 2018 / 0186076 to Dow Corning Corp., and U.S. Patent Application Publication No. 2019 / 0100626 to Lawrence Livermore National Security LLC, each of which is hereby incorporated by reference in its entirety. Other suitable elastomeric resins are described, for example, in U.S. Patent Application Publication No. 20160319150 to Cornell University.

[0154] Optionally, the composition may further optionally a non-magnetic filler. The nonmagnetic filler may be, for example, an organic filler, an inorganic filler, a ceramic powder, or combinations thereof. The organic filler may be a polymer, such as, but not limited to, polystyrene, polyethylene, polypropylene, polysulfone, polyamide, polyimide, polyetheretherketone, etc. The organic filler can also be a smaller molecule either amorphous or crystalline in nature, and can be of in various shapes and sizes. The inorganic filler or ceramic powder can be any inorganic compounds that are compatible with the Attorney Docket No. 10776-035W01 curing chemistry. Examples include, but are not limited to, silicon dioxide, titanium dioxide, zirconium dioxide, barium titanate, strontium titanate, etc. A mixture of more than one inorganic or organic with inorganic fillers are also suitable.

[0155] In embodiments including the non-magnetic filler, the non-magnetic filler can be present as any suitable wt. % of the composition, such as about 0.01 wt. % to about 90 wt. %, about 1 wt. % to about 80 wt. %, about 5 wt. % to about 80 wt. %, about 10 wt. % to about 80 wt. %, about 15 wt. % to about 80 wt. %, about 25 wt. % to about 80 wt. %, about 30 wt. % to about 80 wt. %, about 40 wt. % to about 80 wt. %, about 50 wt. % to about 75 wt. %, about 55 wt. % to about 75 wt. %, about 60 wt. % to about 70 wt. %, alternatively about 0.1 wt. %, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70 wt. % or more.

[0156] The non-magnetic filler can have any suitable particle size, e.g., the longest dimension of the particle, such as the average longest dimension. For example, the nonmagnetic filler can have a primary particle size of about 5 to about 100, about 10 to about 90, about 20 to about 80, about 30 to about 70, about 40 to about 60, or about 50, microns, alternatively 5 microns or less, alternatively 100 microns or more. As used herein, “primary” particle size refers to the actual particles in their un-conglomerated state, which can optionally conglomerate to form larger “secondary” particles.

[0157] Any of the compositions may optionally and independently further comprise additional ingredients or components (“additives”). Examples of additional ingredients include, but are not limited to, adhesion promoters; dyes; pigments; anti-oxidants; initiators for crosslinking; carrier vehicles; heat stabilizers; flame retardants; thixotropic agents; flow control additives; inhibitors; extending and reinforcing fillers; and cross -linking agents. One or more of the additives can be present as any suitable wt. % of the composition, such as about 0.1 wt. % to about 15 wt. %, about 0.5 wt. % to about 5 wt. %, or about 0.1 wt. % or less, about 1 wt. %, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or about 15 wt. % or more of the composition.

[0158] EXAMPLES

[0159] Example 1: Proof of Principle Sensor Array

[0160] Described herein is an example magnetic sensor array comprising a plurality of plurality of magnetic force sensors disposed in relative position with respect to one another Attorney Docket No. 10776-035W01 within a matrix. In this example, the magnetic sensor array takes the form of a working and validated wireless insole prototype, which can be inserted into the show of a wearer.

[0161] The example array includes circuitry that provides suitable battery life and data bandwidth for use in various applications when worn by a user as an insole. For example, the hardware and / or embedded software systems can be used for gait analysis / diagnosis, gait monitoring (e.g., at-home gait monitoring), physical therapy (e.g., improvement of gait), physical therapy / rehabilitation, training (e.g., athletic training), methods of injury prevention, footwear selection, insole selection, etc. In some examples, the example array can include circuitry that provides sample gait data from a user at 300Hz and is capable of 16 hours continuous at-home use.

[0162] An example sensor array is shown in FIG. 19. These insoles were able to record data at greater than 300Hz, and utilizing appropriate sleep modes, last for at least 3 days of continuous use.

[0163] Multiple sensor arrangements within the insole were evaluated against 3D force plates to optimize the number and arrangement of sensors in the array to maximize accuracy. Multiple insole sensor arrangements were evaluated to determine which arrangement(s) can effectively capture all foot forces. The example insoles validated against a standard 3D force plate to demonstrate that the insoles exhibited > 90% accuracy (R2) vs a standard 3D force plate.

[0164] Specifically, validation testing was completed on a number of insoles of different sizes (n= 13) against a gold-standard 3D force plate. The example insoles exhibited an overall average accuracy of 95.6% for all movements tested, which is much higher than originally anticipated, confirming our success in optimizing sensor placement.

[0165] Two working cloud databases were also developed for the insoles which could both easily upload data from the insoles immediately, either automatically or upon request, depending on the needs of the user. Thus, the insoles and accompanying software allow for: 1) live viewing and cloud uploading 16 hours of at-home data collected at 300 Hz, and 2) measuring ground reaction forces with similar accuracy to standard 3D force plates. Aspects of this work are described in more detail below.

[0166] Insole Electrical and Mechanical Design (Sensor Placement and Battery)

[0167] Building on the proof of concept prototypes, the key component improvements were optimized sensor placement, more comfortable mechanical design, and wireless data logging over extended periods of time. Utilizing the overarching trends from discussions Attorney Docket No. 10776-035W01 with clinician stakeholders and published literature in the gait analysis and foot pressure mapping spaces, we designed the location and number of sensors to efficiently measure force transmission through the foot for a wide variety of individual wearers. We strategically placed 15 sensors under each of the critical portions of the foot, identified through pressure maps and comparative analysis. We included two rows of sensors in the ball of the foot, and five individual sensors in the heel to ensure accurate capture for varying foot size and conformation from these critical components of the foot during gait analysis. We manufactured two sensor layouts, that were both scalable to incremental shoe sizes and an efficient use of available space that maintains the necessary distance between magnetometers to enhance accuracy and performance. Additionally, we incorporated a control sensor dedicated to monitoring and compensating for any variations in ambient magnetic fields, ensuring reliable sensor performance and data integrity across different environments in which the insoles are worn. The optimized sensor placement and the associated flex circuitry is shown in FIG. 19A.

[0168] The mechanical insole design and circuit integration were successfully combined enhance user comfort during extended wear periods. The internal structure of the insole was modified to include a compartment for the battery within the natural arch support, optimizing space utilization without compromising the ergonomic integrity of the insole. The new design ensures that the added battery weight is evenly distributed, minimizing pressure points and maintaining the natural contours of the foot. The battery compartment can accommodate larger batteries that will extend operational function over multiple days, facilitating at least 4 hours of continuous data collection from all 15 sensors, while maintaining sustained comfort and functionality for users in various applications. Stakeholder interviews indicated that several minutes of data collection per day would be sufficient for understanding gait patterns and identifying critical changes due to illness progression or indication of disease onset. In light of this, the insoles were designed to enter a sleep mode after collecting 30 minutes of gait data per day such that the insoles can be used continuously for several days without needing to be charged. Therefore, this hardware / software design greatly exceed the goal of 16 hours of battery life.

[0169] Clinicians also emphasized that collecting and offloading data episodes at a specific time (, instead of utilizing live data capture) would be beneficial for clinician and patient acceptance. This modification allows for extended battery life by incorporating active gait monitoring episodes with sleep mode and does not require a maintained Bluetooth Attorney Docket No. 10776-035W01 connection for live data viewing. The circuitry and firmware was designed to include data storage capability via SD card and protocols to control data collection via Bluetooth. The insoles also have the capability for live data viewing for research and protocol refinement. All data collected during validation testing described below was uploaded to the Google Firebase cloud, without issue.

[0170] Once the insoles were redesigned to incorporate different battery sizes within the arch support, several different battery sizes / strengths were assessed. We tested 400mAh and 500mAh batteries. While all 15 sensors were actively collecting data, the insoles were worn until the batteries died. We completed this testing with 3 sets of insoles and 3 batteries of each size. We confirmed that, on average, we could read continuous data from all sensors for 3.1 and 3.6 hours, respectively. Therefore, with appropriate use of sleep mode limiting data collection to a maximum of 1 hour of gait measurement per day, the batteries will last at least 3 full days of continuous use without needing to be recharged. The system is capable of collecting data from all 15 sensors at >300Hz.

[0171] However, there is a tradeoff between the raw noise levels of the magnetometer, data collection frequency, and battery life. For the purpose of validation work, we chose to maximize data fidelity, i.e., low magnetometer noise levels to ensure the insoles had the best chance to achieve high accuracy. Therefore, we set the data collection frequency to 45Hz during the validation work as this would yield the most appropriate understanding of the true accuracy of the sensor insole system itself. Importantly, since the insole circuits were designed, newer magnetometer technology (Melexis MLX90394) has been released with a drastically better noise / data frequency trade off than the magnetometers used in the current work (Melexis MLX90392). Going forward, newer magnetometers can be employed which will allow for a sample frequency >300Hz while maintaining the same low noise level we required for this validation study.

[0172] Example insole prototypes are shown in several stages of manufacturing in FIG. 19. To ensure both comfort and mechanical integrity over extended wear periods, have utilized a silicone material as the matrix with properties closely resembling those of gel shoe insoles. This material selection effectively mimics the cushioning and support provided by traditional gel insoles, thereby enhancing user comfort, while maintaining accuracy of the sensors. The insoles were designed to fit seamlessly into standard athletic shoes (FIG. 19C), ensuring compatibility and ease of use without compromising the footwear's original fit and function. We manufactured and validated the accuracy for multiple sizes. Specifically, Attorney Docket No. 10776-035W01 insoles for a women’s size 5 / 6 and a men’s size 11 / 12 were completed to capture the smaller and larger end of the expected needs for the clinical study.

[0173] Insole Calibration and Validation

[0174] To facilitate external validation testing of the insoles, we developed machine learning calibration procedures. Because of the complexity of converting raw signals from the magnetometers into force when sensors are integrated into shoe insoles in various quantities and layouts, we developed a machine learning algorithm that can generalize to any insole and accounts for individual sensor variability. For each insole, we collected ~12 minutes of continuous data wearing the insoles and standing atop a 3D force plate (Fig. 20A), while doing static (e.g. standing, standing with weight, postural sway) and dynamic movements (e.g. walking, squats, lunges, change of direction, shuffle). We collected several trials of movements to capture comprehensive training data, followed by a separate collection of test data with a different set of movements. Utilizing both the force plate and the insole data, algorithms were utilized to convert the magnetic measurements to force, and subsequently compare the accuracy of the predicted force measurements of the insoles to the ground truth measured forces from the force plates, as shown in Fig. 20B. These results are reported in normalized root mean square error, providing an indication of the accuracy of the insole measurements

[0175] The final validation testing for the insoles was completed with external partners. Over several days, nine insoles of various sizes and two sensor arrangements were validated. Each insole was worn atop a Bertec 3D force plate, while the user performed at least 12 trials of each of the following movements: shuffle steps, standing with weight shift, squats, walking, lunges, marching, change in direction walking, and weighted walking, standing and shuffling. These movements were designed to capture both functional movements that decline with age and gait patterns. Because each wearer had a slightly different footprint within the shoes, and will tie shoes differently, we concluded that at this stage, individual calibrations for each wearer against 3D force plates increased accuracy of the predictive model. This approach enhanced the model’s ability to generalize and accurately predict forces during diverse movements, ultimately improving the insole's performance, reliability, and usability of the data for future gait analysis. Table 1 presents a selection of the error results for several movements tested.

[0176] On average, the overall normalized root mean square error (NRMSE) for all insoles tested across all movements was 4.62, 3.74, and 6.32 in the X, Y, and Z axes respectively. Attorney Docket No. 10776-035W01

[0177] This indicates on average the insoles were >95% accurate. For several insoles, additional movements were tested with the following NRMSE in X, Y, Z respectively: standing with weight shift: 4.13, 2.62, 4.92, lunges: 4.29, 4.62, 5.14, march in place: 3.51, 2.31, 5.56, change of direction steps: 5.61, 4.54, 6.91, weighted walking: 3.41 , 4.33, 7.04, weighted stand with weight shift: 3.70, 4.18, 5.22 and weighted shuffle step: 3.68, 2.81, 7.51. As we continue to tailor the machine learning algorithms to better account for changes in individual wearers, optimize number of sensors, sensor location and sensor production quality, we anticipate that error to continue to decrease. For the insoles manufactured as in FIG. 19, a representative set of specific movement validation data for an Axiostride insole is plotted in FIG. 21. The data trace in red represents the force in Newtons predicted by the insole sensors during a forward and backward step (walking) series, change of direction steps, squats, and a series of forward and lateral lunges. The blue trace in the plot is the measured force in Newtons from a stationary Bertec 3D force plate which acts as the ground truth. We recognize that shoe fit is critical to decreasing error and will continue to integrate compensation parameters into the machine learning algorithms as we continue to analyze the validation data. In addition, we are confident that incorporating the newer higher performance magnetometer chips and continuing to optimize tradeoffs between data fidelity and sampling rates would again improve the insoles to higher and higher accuracy levels.

[0178] Table 1. Validation testing results presented as normalized root mean square error in the X, Y, and Z axis ground reaction forces between the ground truth 3D force plate and insoles across all movements and tests.

[0179] We also verified that the calibration holds over multiple episodes of data collection and wear. In one preliminary test, the error remained less than 6% over data collection Attorney Docket No. 10776-035W01 episodes over two days. Although we anticipate our accuracy to improve significantly with further refinement of our machine learning algorithms, our current data indicates that the insoles are significantly more accurate (just 2-6% error) than the goal we set out to achieve of less than 10% error in comparison to gold standard 3D force plates. This suggests that with our calibration procedures, the force data collected from the insoles will be sensitive and accurate enough to differentiate different gait patterns.

[0180] Additionally, we performed a series of sensor dropout studies, where data from certain sensors were removed from validation runs, to further explore options for sensor placement and reducing overall number of sensors to optimize data bandwidth tradeoffs. To compare to the original data set including all 15 sensors, we tested iterations with only 11 sensors active, 8 sensors active and 5 sensors active. The NRMSE (X, Y, and Z axes) remained low with all 15 sensors (3.68, 4.53, 3.64), with 11 sensors (4.75, 3.98, 4.16) and with 8 sensors (4.24, 5.31, 3.89), but increased when tested with only 5 sensors (4.32, 5.35, 10.48). These results indicate that we can potentially decrease the number of sensors without compromising data accuracy to a significant extent, thus allowing a higher sample rate while maintaining battery life.

[0181] We validated the insoles, database and hardware functionality, and calibration algorithms. As a follow-on study, we will perform a more robust empirical data-oriented version of the sensor arrangement study described above. Statistical analysis will be performed on data collected from the insoles during these studies to see which sensors of the 15 are most critical for capturing foot forces, such that sensor arrangement can be optimized via this data for future iterations of the insoles. This data will be utilized to define the minimum number of sensors and the arrangement of sensors which are necessary for accurately capturing 3D forces through the insoles. These data will inform the next iterations of the insoles which will then be fabricated with optimized sensor arrangements and leverage higher sampling rates and battery life depending on how many sensors are determined to be needed by the study. The next generation of insoles will then be manufactured in a range of sizes.

[0182] Significance

[0183] We have developed 3D force sensing shoe insoles that allow for the high-fidelity data of 3D force plates to be automatically monitored by wearable technology during at- home real-life activities. These insoles are the first system that can measure 3D ground reaction forces via shoe insoles that fit in normal shoes. Healthcare providers will screen Attorney Docket No. 10776-035W01 and monitor at-risk patients without needing a gait laboratory visit, as patients use insoles inside any brand shoe and continue normal at-home activities. The insoles will collect and securely transmit gait data to the cloud to be processed with artificial intelligence (Al) algorithms to profile walking deficits, screen for neurological disease gait biomarkers, and inform disease progression. Results of this screening, such as high variability in push off force or low gait speed, can trigger a more formal diagnosis or intervention.

[0184] Maintaining the ability to move and complete activities of daily living with aging is essential, as loss of functional mobility associated with aging is the leading cause of dangerous falls and loss of independence in the form of nursing home admittance. Approximately 60% of community-residing individuals >80 years-old have a gait disorder, and abnormal gait patterns are associated with a two-fold increased risk of institutionalization and death. Three-dimensional force plates, motion capture technologies, and gait mats are commonly used tools for analyzing gait function, but their lack of portability, requirement for trained personnel, and cumbersome data analysis render them unfeasible for scalable screening. To address these limitations, researchers have begun pursuing wearable technologies. No currently available wearable technology includes 3D force and accelerometry measurement which are both critical for fully understanding gait and monitoring walking deterioration. In addition, current wearables suffer from poor reliability, require manual data analysis, and require patients to attach the sensor to an inconvenient location, which is not practical for daily use and prevents them from being scalable solutions.

[0185] These insoles will alleviate these limitations as a scalable, accessible solution by providing a robust and user-friendly option for at-home gait analysis that automatically delivers neurological disease and fall risk screening directly to physicians. These insoles are distinct from current gait analysis technologies because they are a wearable technology capable of measuring 3D forces and 3D acceleration at multiple discreet locations across the feet. This capacity for high-fidelity sensing can provide a significantly more robust signal for training Al algorithms than any other currently available wearable technology. While previous research has shown machine learning / AI can be extremely useful for distinguishing specific abnormal gait features, no such algorithm has reached the level of clinical utility and adoption due to limitations in the feasibility and fidelity of the sensor technologies used.

[0186] Future Efforts Attorney Docket No. 10776-035W01

[0187] For further validation, we will enroll 100 subjects, men and women of all races and ethnic backgrounds who are community dwelling and 65 years of age or older. Potentially eligible participants will have the study explained to them. During a first visit, questionnaires and data collection will occur to ensure participants are eligible and medically safe for participation. During a second visit, participants will wear insoles and perform several functional mobility tests that are currently used in the clinic to assess fall risk. These physical performance tests will be carried out using standardized protocols by trained and experienced staff. The outcome variables of these physical performance tests have been used in many previous research studies to examine functional mobility and predict fall risk, understand functional decline due to aging, and assess exercise intervention efficacy.

[0188] We will train an Al algorithm to assess functional mobility and fall risk via 3D ground reaction force data recorded from the shoe insoles during normal gait cycles. An Al approach will use the entire ground reaction force data trace recorded by the insoles during 5 normal gait cycles to predict whether participants fall above for below the critical cut points on each functional mobility test. Finally, we will compare the ability of the traditional gait parameters (averaged peak vertical / anterior / posterior ground reaction forces, stride frequency) and physical performance test outcome variables against the capacity of the Al approach to predict falls. We anticipate the Al prediction models will compare favorably with previous prediction models in terms of accuracy and ease of implementation. Successful completion of this study will yield a technology that has shown utility in enhancing functional mobility and fall risk prediction from standard gait testing, especially in that the Al algorithm will facilitate unsupervised functional gait assessment which will be tested.

[0189] These studies will train the Al algorithm for classifying functional mobility within a laboratory setting, however, we also aim gain these types of understanding from unsupervised gait that occurs in an at-home setting. Therefore, we will also perform a 1- month pilot study, testing the performance of the Al algorithm in the desired at-home setting, where the data collected for the Al is unsupervised. This will require the Al to be able to determine normal gait cycles from other activities like standing from a seated position or shifting balance while standing. While testing is ongoing, 20 of the 100 subjects will be randomly selected to have insoles sent home with them for a 1 -month period. The Attorney Docket No. 10776-035W01 subjects will be instructed to wear shoes with the shoe insoles inserted as often as possible and data will be recorded during the entire 1 - month period.

[0190] Data recorded from the insoles will be processed to isolate gait events that serve as input to the trained Al. With these criteria, gait cycle events can be identified and isolated from the data, which can then be input into the Al for functional mobility classification. Since gait can be somewhat stochastic based on the environment, mental load, and other factors, we will investigate using anywhere between 1-100 gait cycles for classification. In the case where multiple gait cycles are used, each individual gait cycle will be classified, and the majority of classifications will determine the final classification (e.g. 55 cycles are classified as functional immobile, then the subject is classified as functionally immobile). Again, we anticipate that the Al algorithm will prove effective in detecting gait events from unsupervised settings and classifying individuals according to their functional mobility. This will demonstrate that the insoles are capable of providing functional mobility and gait insights without requiring trained personnel or lab equipment.

[0191] The success of these insoles as a gait monitoring tool that can be used to track changes in functional mobility over time or track progression due to exercise interventions is partially dependent on whether users find utility or enjoyment from the product such that they will continue to use it. In the cases of these insoles, this means the insoles must be comfortable and that individuals enjoy wearing them each day.

[0192] These insoles can provide multi 3D force sensing capabilities. Optionally, these insoles can be used in combination with standard 9-axis Inertial Measurement Units (IMUs) to provide for 3D force and 3D motion insoles. These insoles can be used for applications including:

[0193] External load monitoring for athletes via measuring 3D ground reaction forces during practice, game, and other settings;

[0194] Athlete readiness monitoring via vertical jump testing or other sport / rehab related movement protocols;

[0195] For properly sizing and / or fitting footwear such as shoes or insoles;

[0196] Assessing and as a coaching aid for sport specific movements such as pitiching, other throwing movements, jumping, golf swings, batting motions in baseball and other bat sports, etc.;

[0197] Remote (at-home, or “in the wild”) gait screening and monitoring for assessment of gait disorders which may relate to aging processes or neurodegenerative diseases; Attorney Docket No. 10776-035W01

[0198] Understanding ground reaction forces, shoe fit, foot friction, etc. which may cause foot ulcers especially in individuals with diabetic peripheral neuropathy, and for assessing therapies aimed at reducing such unwanted stimuli or for healing injuries and ulceration;

[0199] As a higher- fidelity activity monitor capable of more accurate step counting in addition or measuring external load (via 3D force and motion sensing) for individuals seeking to improve heal and function through physical activity;

[0200] As a gait analysis tool in gait labs for assessment of gait dysfunction from all potential causes;

[0201] As a part of “digital twin” systems designed to intake data from human movement, and model stresses and strains on the body to improve understanding of biomechanics on an individual level.

[0202] All other uses of smart insole technology that require 3D ground reaction force measurement or the combination of 3D force and 3D motion measurements

[0203] Lessons Learned and Problems Solved

[0204] During fabrication of the example sensor arrays, it was discovered that proper alignment of magnets (magnetic actuators) with magnetometers during fabrication of the force sensors was important for producing consistent results.

[0205] Specifically, aligning / gluing magnets individually creates inconsistencies in alignment with magnetometers, stretches / crimps silicone between sensors which creates instability in the signal, lower durability of bond between insole silicone and insole circuit, and takes an infeasible amount of time. Therefore, when fabricating sensor arrays, a layer of adhesive was applied across the entire insole circuit board in one go, and all 15 magnets were aligned with their magnetometers in parallel by shifting the magnet laden insole around on the magnets as a unit. While there was a significant learning curve this yielded much higher consistency for signal and mechanical durability of insole.

[0206] The selection of appropriate materials also played a role in producing insoles with improved wearability. Including a high concentration of magnetic powder makes the magnetic composite portions of the force sensors stiffer than the surrounding area. For wearable applications this is not inappropriate as it may create discomfort. By using a silicone for the silicone magnetic composite portion with a softer shore hardness than the pure silicone portions of the sensor insole, we were able to approximately equate the stiffness of these components so we retain a powerful magnetic composite for sensor functionality while reducing differences in stiffness which may cause discomfort to wearers. Attorney Docket No. 10776-035W01

[0207] We also studied sensor location and number. Because the vast majority of forces through the foot goes through the heel and the ball of the foot, accuracy was improved by positioning the majority of sensors in these locations as well. In addition, sensors were spread at those locations, that is, two rows of sensors near the ball of the foot, and 5 sensors in a cross shape in the heel area to ensure that regardless of variations in foot shape and size we have ample ability to detect forces in these two important areas. While the insoles were made with 15 sensors, we performed testing which showed the insoles retain similar accuracy with removing data from certain sensors down to 8 sensors, thus it is possible to strategically position just 8 sensors in future prototypes but retain accuracy (far more testing needs to be done on this one).

[0208] Further Examples of Sensor Arrays

[0209] The sensor arrays described herein can be disposed on or within a helmet or other protective headwear for monitoring and quantifying head impacts or injuries. See FIG. 22. Likewise, the sensor arrays can be disposed within athletic equipment (e.g., pads) or other personal safety equipment (e.g., vests, knee pads, etc.) to monitoring and quantifying impacts or injuries.

[0210] The sensor arrays described herein can be formed as (or incorporated within) cushions for monitoring sensitive electronic components or other packages in rockets or other containers to quantify movement, vibrations, shock, forces that occur on packaging or sensitive components. See FIG. 23.

[0211] The sensor arrays described herein can be disposed on or within in gloves or other wearable padding for assisting in manufacturing and manufacturing trainings, monitoring ergonomics, monitoring workloads, measuring fit of glove or suits or other apparel or gear. See FIG. 24.

[0212] The sensor arrays described herein can be embedded within prosthetic liner for objective assessment of fit. Monitoring activity, monitoring load at interface of residual limb and prosthesis, measuring forces which may cause injury or ulceration at interface and aiding in therapies for healing such injuries. See FIG. 25A-25B.

[0213] The sensor arrays described herein can be used to form 3D force plates for biomechanics analysis or other uses of 3D load cells. See FIG. 26A-26E. Sensor embedded load cells, and devices constructed with such load cells are capable of extremely high levels of accuracy in comparison to typical gold standard force measurement systems Attorney Docket No. 10776-035W01

[0214] The sensor arrays described herein can be used 3D force sensing grips for tools and sporting implements, such as golf clubs, baseball or other sport bats, to optimize user performance.

[0215] The sensor arrays described herein can be used as robotic fingertips or tactile skin with discrete 3D force sensing nodes.

[0216] The sensor arrays described herein can be used as wearable smart cushions for monitoring physiology such as heart rate monitors, respiration sensor, or other physiological signals.

[0217] The sensor arrays described herein can be used smart cushions for measuring fit, ergonomics, causes of discomfort in suits or wearables or other gear such as space suits.

[0218] The compositions and methods of the appended claims are not limited in scope by the specific compositions and methods described herein, which are intended as illustrations of a few aspects of the claims and any compositions and methods that are functionally equivalent are intended to fall within the scope of the claims. Various modifications of the compositions and methods in addition to those shown and described herein are intended to fall within the scope of the appended claims. Further, while only certain representative compositions and method steps disclosed herein are specifically described, other combinations of the compositions and method steps also are intended to fall within the scope of the appended claims, even if not specifically recited. Thus, a combination of steps, elements, components, or constituents may be explicitly mentioned herein; however, other combinations of steps, elements, components, and constituents are included, even though not explicitly stated.

Claims

Attorney Docket No. 10776-035W01WHAT IS CLAIMED IS:

1. A magnetic sensor array comprising a plurality of magnetic force sensors disposed in relative position with respect to one another within an elastomeric matrix; wherein each of the plurality of magnetic force sensors comprises a magnetic actuator having a proximal end and a distal end, the magnetic actuator comprising an elastomeric resin; and a population of magnetic particles dispersed within the elastomeric resin.

2. The sensor array of claim 1 , wherein the elastomeric matrix comprises a crosslinkable composition.

3. The sensor array of any one of claims 1-2, wherein the elastomeric matrix comprises a crosslinkable silicone composition.

4. The sensor array of any one of claims 1-3, wherein the magnetic sensor array comprises from 2 to 50 magnetic force sensors, such as from 5 to 50 magnetic force sensors, from 5 to 40 magnetic force sensors, from 5 to 30 magnetic force sensors, from 5 to 25 magnetic force sensors, from 5 to 20 magnetic force sensors, from 5 to 15 magnetic force sensors, from 8 to 50 magnetic force sensors, from 8 to 40 magnetic force sensors, from 8 to 30 magnetic force sensors, from 8 to 25 magnetic force sensors, from 8 to 20 magnetic force sensors, or from 8 to 15 magnetic force sensors.

5. The sensor array of any one of claims 1-4, wherein the elastomeric matrix comprises a film or sheet.

6. The sensor array of claim 5, wherein the film or sheet has a thickness of less than 10 mm, such as a thickness of less than 9.5 mm, less than 9 mm, less than 8.5 mm, less than 8 mm, less than 7.5 mm, less than 7 mm, less than 6.5 mm, less than 6 mm, less than 5.5 mm, less than 5 mm, less than 4.5 mm, less than 4 mm, less than 3.5 mm, less than 3 mm, less than 2.5 mm, less than 2 mm, or less than 1.5 mm.Attorney Docket No. 10776-035W017. The sensor array of any one of claims 5-6, wherein the film or sheet has a thickness of from 0.5 mm to 7.5 mm, such as a thickness of from 0.5 mm to 7 mm, from 0.5 mm to6.5 mm, from 0.5 mm to 6 mm, from 0.5 mm to 5.5 mm, from 0.5 mm to 5 mm, from 0.5 mm to 4.5 mm, from 0.5 mm to 4 mm, from 0.5 mm to 3.5 mm, from 0.5 mm to 3 mm, from 0.5 mm to 2.5 mm, from 0.5 mm to 2 mm, from 0.5 mm to 1.5 mm, from 0.75 mm to7.5 mm, from 0.75 mm to 7 mm, from 0.75 mm to 6.5 mm, from 0.75 mm to 6 mm, from 0.75 mm to 5.5 mm, from 0.75 mm to 5 mm, from 0.75 mm to 4.5 mm, from 0.75 mm to 4 mm, from 0.75 mm to 3.5 mm, from 0.75 mm to 3 mm, from 0.75 mm to 2.5 mm, from 0.75 mm to 2 mm, from 0.75 mm to 1.5 mm, from 1 mm to 7.5 mm, from 1 mm to 7 mm, from 1 mm to 6.5 mm, from 1 mm to 6 mm, from 1 mm to 5.5 mm, from 1 mm to 5 mm, from 1 mm to 4.5 mm, from 1 mm to 4 mm, from 1 mm to 3.5 mm, from 1 mm to 3 mm, from 1 mm to 2.5 mm, from 1 mm to 2 mm, or from 1 mm to 1.5 mm.

8. The sensor array of any one of claims 5-7, wherein the film or sheet has a surface area of at least 25 mm2, such as a surface area of from 25 mm2to 1 m2.

9. The sensor array of any one of claims 1-8, wherein the array further comprises circuitry configured to store and / or transmit outputs from the plurality of magnetic force sensors.

10. The sensor array of any one of claims 1-9, wherein the array further includes a power supply configured to power the plurality of magnetic force sensors.

11. The sensor array of any one of claims 1-10, wherein each of the plurality of magnetic force sensors further comprises: a magnetometer operatively positioned in proximity to the distal end of the magnetic actuator; and a spacer disposed between the magnetometer and the distal end of the magnetic actuator, thereby creating a standoff distance between the magnetometer and the distal end of the magnetic actuator; wherein the magnetic actuator and the magnetometer are sized relative to one another such that a force applied to the magnetic actuator in a x-y plane relative to the magnetometer, along a z-axis relative to the magnetometer, or any combination thereofAttorney Docket No. 10776-035W01 produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force.

12. The sensor array of claim 11 , wherein the magnetic actuator and the magnetometer are sized relative to one another such that compression of the magnetic actuator under an applied force along the z-axis relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force.

13. The sensor array of any one of claims 1-2, wherein the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force.

14. The sensor array of any one of claim 1-4, wherein the magnetic actuator has a largest cross-sectional dimension that is smaller than a largest cross-sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force.

15. The sensor array of claim 14, wherein the largest cross-sectional dimension of the magnetic actuator is from 5% to 80% of the largest cross-sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force.

16. The sensor array of any one of claims 1 1- 15, wherein the magnetic actuator has a largest cross-sectional dimension that is smaller than a largest cross-sectional dimension of the magnetometer when the magnetic actuator is compressed by 40% under an applied force.

17. The sensor array of claim 16, wherein the largest cross-sectional dimension of the magnetic actuator is from 50% to 90% of the largest cross-sectional dimension of the magnetometer when the magnetic actuator is compressed by 40% under an applied force.

18. The sensor array of any one of claims 11-17, wherein the magnetic actuator has a largest cross-sectional area that is smaller than a largest cross-sectional area of the magnetometer when the magnetic actuator is not subjected to an applied force.Attorney Docket No. 10776-035W0119. The sensor array of claim 18, wherein the largest cross-sectional area of the magnetic actuator is from 50% to 90% of the largest cross-sectional are of the magnetometer when the magnetic actuator is not subjected to an applied force.

20. The sensor array of any one of claims 11-19, wherein the magnetic actuator has a largest cross-sectional area that is smaller than a largest cross-sectional area of the magnetometer when the magnetic actuator is compressed by 40% under an applied force.

21. The sensor array of claim 20, wherein the largest cross-sectional area of the magnetic actuator is from 50% to 90% of the largest cross-sectional area of the magnetometer when the magnetic actuator is compressed by 40% under an applied force.

22. The sensor array of any one of claims 11-21, wherein the magnetic actuator and the magnetometer are sized relative to one another such that compression of the magnetic actuator under a window of applied forces ranging from an applied force effective to compress the magnetic actuator by 5% to an applied force effective to compress the magnetic actuator by 40% produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force across the window of applied forces.

23. The sensor array of any one of claims 11-22, wherein a force applied to the magnetic actuator in the x-y plane relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force, wherein a force applied to the magnetic actuator along the z-axis relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force, or any combination thereof.

24. The sensor array of any one of claims 11-22, wherein the magnetic actuator and the magnetometer are sized relative to one another such that compression of the magnetic actuator under a window of applied forces ranging from an applied force effective to compress the magnetic actuator by 3% to an applied force effective to compress the magnetic actuator by 20% produces a magnetic field response that is increasing andAttorney Docket No. 10776-035W01 proportionate or decreasing and proportionate to the applied force across the window of applied forces.

25. The sensor array of claim 11 , wherein the magnetic actuator and the magnetometer are sized relative to one another such that shear of the magnetic actuator under an applied force in a x-y plane relative to the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force.

26. The sensor array of claim 25, wherein the magnetometer produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force.

27. The sensor array of any one of claims 25-26, wherein the magnetic actuator has a largest cross-sectional dimension that is smaller than a largest cross-sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force.

28. The sensor array of claim 27, wherein the largest cross-sectional dimension of the magnetic actuator is from 5% to 80% of the largest cross-sectional dimension of the magnetometer when the magnetic actuator is not subjected to an applied force.

29. The sensor array of any one of claims 25-28, wherein the magnetic actuator has a largest cross-sectional dimension that is smaller than a largest cross-sectional dimension of the magnetometer when the magnetic actuator is sheared by 40% under an applied force.

30. The sensor array of claim 29, wherein the largest cross-sectional dimension of the magnetic actuator is from 50% to 90% of the largest cross-sectional dimension of the magnetometer when the magnetic actuator is sheared by 40% under an applied force.

31. The sensor array of any one of claims 25-30, wherein the magnetic actuator has a largest cross-sectional area that is smaller than a largest cross-sectional area of the magnetometer when the magnetic actuator is not subjected to an applied force.Attorney Docket No. 10776-035W0132. The sensor array of claim 31, wherein the largest cross-sectional area of the magnetic actuator is from 50% to 90% of the largest cross-sectional are of the magnetometer when the magnetic actuator is not subjected to an applied force.

33. The sensor array of any one of claims 25-32, wherein the magnetic actuator has a largest cross-sectional area that is smaller than a largest cross-sectional area of the magnetometer when the magnetic actuator is sheared by 40% under an applied force.

34. The sensor array of claim 33, wherein the largest cross-sectional area of the magnetic actuator is from 50% to 90% of the largest cross-sectional area of the magnetometer when the magnetic actuator is sheared by 40% under an applied force.

35. The sensor array of any one of claims 25-34, wherein the magnetic actuator and the magnetometer are sized relative to one another such that shear of the magnetic actuator under a window of applied forces ranging from an applied force effective to induce a shear strain of the magnetic actuator by 5% to an applied force effective to induce a shear strain of the magnetic actuator by 40% produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force across the window of applied forces.

36. The sensor array of any one of claims 25-35, wherein the magnetic actuator and the magnetometer are sized relative to one another such that shear of the magnetic actuator under a window of applied forces ranging from an applied force effective to induce a shear strain of the magnetic actuator by 3% to an applied force effective to induce a shear strain of the magnetic actuator by 20% produces a magnetic field response that is increasing and proportionate or decreasing and proportionate to the applied force across the window of applied forces.

37. The sensor array of any one of claims 11-36, wherein the magnetic actuator has a largest cross-sectional dimension of from 1 mm to 25 mm.

38. The sensor array of any one of claims 11-36, wherein the magnetic actuator has a substantially circular horizontal cross-section.Attorney Docket No. 10776-035W0139. The sensor array of any one of claims 11-38, wherein the magnetic actuator has a substantially cylindrical shape or a substantially conical shape.

40. The sensor array of any one of claims 11-39, wherein the standoff distance is from greater than 0 mm to 5 mm, such as from greater than 0 mm to 1.5 mm.

41. The sensor array of any one of claims 11-40, wherein the standoff distance is selected to provide a measurable signal such as magnetic field response greater than 100 pT with an applied force.

42. The sensor array of any one of claims 11-41, wherein the spacer is formed from an elastomeric resin, a rigid material, or any combination thereof.

43. The sensor array of any one of claims 11-42, wherein the spacer is formed from an elastomeric resin.

44. The sensor array of any one of claims 11-43, wherein when the spacer is formed from an elastomeric resin, the spacer comprises a portion of a housing that partially or completely encloses the magnetic actuator.

45. The sensor array of any one of claims 11-44, wherein the magnetic particles comprise magnetic microparticles.

46. The sensor array of claim 45, wherein the magnetic microparticles have an average particle size of from 1 micron to 150 microns, such as from 1 micron to 50 microns.

47. The sensor array of any one of claims 11-46, wherein the magnetic particles comprise magnetic nanoparticles.

48. The sensor array of claim 47, wherein the magnetic nanoparticles have an average particle size of from 50 nm to less than 1 micron, such as from 50 nm to 500 nm.Attorney Docket No. 10776-035W0149. The sensor array of any one of claims 11-48, wherein the magnetic particles comprise anisotropic magnetic particles.

50. The sensor array of any one of claims 11-49, wherein the magnetic particles are present in the elastomeric resin in an amount of from 0.1% by weight to 90% by weight, based on the total weight of the elastomeric resin, such as from 50% by weight to 90% by weight, from 40% by weight to 80% by weight, from 30% to 70% by weight, from 20% to 60% by weight, from 15% to 50% by weight, from 0.1% to 50% by weight, from 0.1% to 40% by weight, from 0.1% to 30% by weight, from 0.1% to 20% by weight, from 0.1% by weight to 10% by weight, 0.1% by weight to 5% by weight, from 0.1% by weight to 2.5% by weight, or from 0.1% by weight to 1% by weight, based on the total weight of the elastomeric resin.

51. The sensor array of any one of claims 11-50, wherein the elastomeric resin further comprises a non-magnetic filler, such as silica particles.

52. The sensor array of any one of claims 11-51, wherein the elastomeric resin comprises a crosslinkable composition, such as a crosslinkable silicone composition.

53. The sensor array of claim 52, wherein the elastomeric resin comprises (A) a first organosilicon compound having at least two ethylenically unsaturated moieties per molecule; and optionally (B) one or more additional organosilicon compounds.

54. The sensor array of any one of claims 11-53, wherein dipoles of the magnetic particles are aligned and / or oriented within the magnetic actuator.

55. The sensor array of claim 54, wherein dipoles of the magnetic particles are aligned and / or oriented within the magnetic actuator when the magnetic actuator is compressed by from 10% to 60% under an applied force.

56. The sensor array of any one of claims 11-55, wherein the sensor array further comprises a microcontroller, a processor, or a combination thereof operatively coupled toAttorney Docket No. 10776-035W01 the magnetometer and configured to calculate a force applied to the magnetometer based on a measurement of a change in magnetic field strength.

57. The sensor array of any one of claims 11-56, wherein the magnetic actuator exhibits a Shore A Hardness within 25% (e.g., within 20%, within 15%, or within 10%) of a Shore A Hardness of the elastomeric matrix.

58. The sensor array of any one of claims 1-57, each of the magnetic force sensors in the magnetic sensor array are separated from their nearest neighboring magnetic force sensor by a minimum distance of at least 5 mm, such as at least 10 mm, at least 15 mm, at least 20 mm, at least 25 mm, at least 30 mm, at least 35 mm, at least 40 mm, at least 45 mm, or at least 50 mm.

59. The sensor array of any one of claims 1-58, wherein the sensor array further comprises an integrated motion sensor, such as a 9-axis inertial measurement unit.

60. Footwear comprising the sensor array of any one of claims 1-59.

61. The footwear of claim 60, wherein the footwear comprises an insole.

62. The footwear of any one of claims 60-61, wherein the footwear includes a plurality of magnetic force sensors disposed in proximity to a wearer’ s heel when the footwear is worn by a user.

63. The footwear of claim 62, wherein the footwear includes from 3 to 7 magnetic force sensors disposed in proximity to the wearer’ s heel when the footwear is worn by the user.

64. The footwear of any one of claims 60-62, wherein the footwear includes a plurality of magnetic force sensors disposed in proximity to a ball of a wearer’s foot when the footwear is worn by a user.Attorney Docket No. 10776-035W0165. The footwear of claim 64, wherein the footwear includes from 2 to 8 magnetic force sensors disposed in proximity to the ball of the wearer’s foot when the footwear is worn by the user.

66. The use of the footwear of any one of claims 60-65 for the measurement of gait, for injury prevention, for physical therapy, for the improvement of gait, for the diagnosis or assessment of a neurological disorder or injury, or any combination thereof.

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