Multi-axis tilt estimation and fall remediation
First Claim
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1. A vestibular prosthesis comprising:
- a wearable motion sensing system including accelerometers and gyroscopes, the motion sensing system is configured to generate motion signals indicative of a motion thereof, wherein the motion includes rotation about two distinct axes;
a signal processor in communication with the motion sensing system, the signal processor being configuredto generate a first estimate of a tilt of the motion sensing system based on a nonlinear relationship between output from the accelerometers and quaternions that transform a direction of a gravity vector into a body frame of reference that is stationary with respect to the motion sensing system,to generate a second estimate of the tilt based on output from the gyroscopes,to generate a third estimate of the tilt based on the first estimate and the second estimate, andto represent the first, second, and third estimates as quaternions;
an actuator configured to be triggered responsive to the third estimate of the tilt being in a predetermined region of a decision space having a first dimension representing a value of the tilt and a second dimension representing a rate of change of the tilt.
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Abstract
Among other things, a vestibular prosthesis includes a wearable motion sensing system, the motion sensing system generating a motion signal indicative of a motion thereof, wherein the motion includes rotation about two distinct axes; a signal processor in communication with the motion sensing system, the signal processor being configured to generate an estimate of a tilt of the motion sensing system; and an actuator responsive to the estimate of the tilt made by the signal processor.
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Citations
28 Claims
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1. A vestibular prosthesis comprising:
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a wearable motion sensing system including accelerometers and gyroscopes, the motion sensing system is configured to generate motion signals indicative of a motion thereof, wherein the motion includes rotation about two distinct axes; a signal processor in communication with the motion sensing system, the signal processor being configured to generate a first estimate of a tilt of the motion sensing system based on a nonlinear relationship between output from the accelerometers and quaternions that transform a direction of a gravity vector into a body frame of reference that is stationary with respect to the motion sensing system, to generate a second estimate of the tilt based on output from the gyroscopes, to generate a third estimate of the tilt based on the first estimate and the second estimate, and to represent the first, second, and third estimates as quaternions; an actuator configured to be triggered responsive to the third estimate of the tilt being in a predetermined region of a decision space having a first dimension representing a value of the tilt and a second dimension representing a rate of change of the tilt. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A vestibular prosthesis comprising:
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a wearable motion sensing system including accelerometers and gyroscopes, the motion sensing system is configured to generate motion signals indicative of a motion thereof, wherein the motion includes rotation about two distinct axes; a signal processor in communication with the motion sensing system, the signal processor being configured to generate a first estimate of a tilt of the motion sensing system based on a direction of a gravity vector, in a body frame of reference that is stationary with respect to the motion sensing system, determined based on Euler angles relating a motion of the accelerometers to the tilt of the motion sensing system, to generate a second estimate of the tilt based on Euler angles relating motion of the gyroscopes to the tilt of the motion sensing system, and to generate a third estimate of the tilt based on the first estimate and the second estimate, and an actuator configured to be triggered responsive to the third estimate of the tilt being in a predetermined region of a decision space having a first dimension representing a value of the tilt and a second dimension representing a rate of change of the tilt. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A method of estimating a tilt of a wearer, the method comprising:
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generating, by a motion sensor, motion signals indicative of rotations about at least two axes as experienced by the wearer, wherein generating the motion signals includes generating accelerometer signals and gyro signals, processing the accelerometer signals including determining an accelerometer quaternion, and processing the gyro signals including determining a gyro quaternion; generating, by a processor, a first estimate of the tilt of the wearer based on a nonlinear relationship between the accelerometer signals and quaternions that transform a direction of gravity into a body frame of reference that is stationary with respect to the motion sensing system; generating, by the processor, a second estimate of the tilt of the wearer based on the gyro signals; generating, by the processor, a third estimate of the tilt of the wearer based on the first and second estimates; and providing an output signal to a nervous system of the wearer, the output signal being indicative of the third estimate of the tilt of the wearer and responsive to determining that the third estimate is in a predetermined region of a decision space having a first dimension representing the value of the tilt and a second dimension representing a rate of change of the tilt. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A method of estimating a tilt of a wearer, the method comprising:
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generating, by a motion sensor, motion signals indicative of rotations about at least two axes as experienced by the wearer, wherein generating the motion signals includes generating accelerometer signals and gyro signals, processing the accelerometer signals including determining accelerometer Euler angles, and processing the gyro signals including determining gyro Euler angles; generating, by a processor, a first estimate of the tilt of the wearer based on a direction of a gravity vector, in a body frame of reference that is stationary with respect to the motion sensing system, determined based on the accelerometer Euler angles determined from processing the accelerometer signals; generating, by the processor, a second estimate of the tilt of the wearer based on the gyro signals; generating, by the processor, a third estimate of the tilt of the wearer based on the first and second estimates; and providing an output signal to a nervous system of the wearer, the output signal being indicative of the third estimate of the tilt of the wearer and responsive to determining that the third estimate is in a predetermined region of a decision space having a first dimension representing the value of the tilt and a second dimension representing a rate of change of the tilt. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification