Microfabricated flexible ground reaction sensor cluster for navigation in GPS-denied environments
First Claim
1. A ground reaction sensor cluster (GRSC) comprising the following:
- an array of capacitive pressure and shear sensors, the array comprising a plurality of flexible capacitive sensor cells that detect changes in capacitance in response to a footstep, each cell of the array comprising a plurality of overlapping, fingered capacitors that detect pressure and shear force by determining the change in capacitance in each fingered capacitor, wherein the array of sensors is distributed along a contact portion of a shoe;
a multiplexing receiver that receives the capacitance inputs from each of the plurality of capacitive sensor cells, wherein the multiplexing receiver is communicatively connected to one or more electronic elements that further process the received capacitance inputs to determine, based on the detected pressure and shear forces, the direction and bearing of the footstep.
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Accused Products
Abstract
Embodiments are directed to a ground reaction sensor cluster (GRSC) and to methods for precisely determining zero velocity points and bearing changes using a GRSC and for navigating using a GRSC and an inertial motion unit (IMU) in a global positioning satellite (GPS)-denied environment. The GRSC device itself includes an array of capacitive pressure and shear sensors. The array includes multiple flexible capacitive sensor cells that detect changes in capacitance in response to a footstep. Each cell of the array includes multiple overlapping, fingered capacitors that detect pressure and shear force by determining the change in capacitance in each fingered capacitor. The GRSC device also includes a multiplexing receiver that receives the capacitance inputs from each of the capacitive sensor cells. The multiplexing receiver and other electronic elements further process the received capacitance inputs to determine, based on the pressure and shear forces, the direction and bearing of the footstep.
9 Citations
20 Claims
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1. A ground reaction sensor cluster (GRSC) comprising the following:
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an array of capacitive pressure and shear sensors, the array comprising a plurality of flexible capacitive sensor cells that detect changes in capacitance in response to a footstep, each cell of the array comprising a plurality of overlapping, fingered capacitors that detect pressure and shear force by determining the change in capacitance in each fingered capacitor, wherein the array of sensors is distributed along a contact portion of a shoe; a multiplexing receiver that receives the capacitance inputs from each of the plurality of capacitive sensor cells, wherein the multiplexing receiver is communicatively connected to one or more electronic elements that further process the received capacitance inputs to determine, based on the detected pressure and shear forces, the direction and bearing of the footstep. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for precisely determining zero velocity points and bearing changes using a ground reaction sensor cluster (GRSC), the method comprising:
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detecting a user'"'"'s footstep using an array of pressure and shear sensors distributed along a contact portion of a user'"'"'s shoe, wherein pressure sensing elements of the GRSC measure the distribution of ground reaction and shear sensing elements of the GRSC measure lateral forces and torque; determining a zero point at which the user'"'"'s shoe is at zero velocity based on the detected pressure and shear sensor measurements; determining, based on the lateral force measured by the shear sensor at the zero point, the degree to which the user'"'"'s bearing has changed; and sending the bearing changes to an internal motion unit (IMU) communicatively attached to the GRSC, wherein the IMU uses the determined bearing change to refine its calculated zero point and velocity determinations. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method for navigating using a ground reaction sensor cluster (GRSC) and an inertial motion unit (IMU) in a global positioning satellite (GPS)-denied environment, the method comprising:
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determining that a user has passed into an environment where a GPS device used by the user is no longer receiving GPS signals, wherein the GPS device is communicatively connected to a GRSC and an IMU; detecting the user'"'"'s footsteps using the GRSC, the GRSC comprising an array of pressure and shear sensors distributed along a contact portion of the user'"'"'s shoe, wherein pressure sensing elements of the GRSC measure the distribution of ground reaction and shear sensing elements of the GRSC measure lateral forces and torque; determining a zero point at which the user'"'"'s shoe is at zero velocity based on the GRSC'"'"'s detected pressure and shear sensor measurements; determining, based on the lateral force measured by the shear sensor at the zero point, the degree to which the user'"'"'s bearing has changed; sending the bearing changes to an internal motion unit (IMU) communicatively attached to the GRSC, wherein the IMU uses the determined bearing change to refine its calculated zero point and velocity determinations; and determining the user'"'"'s direction and velocity using the measurements of the GRSC and the IMU to navigate the user until the user'"'"'s GPS device is back in range of GPS satellites. - View Dependent Claims (20)
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Specification