Power measurement method and apparatus
First Claim
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1. An apparatus for estimating power used by a user in performing a vertical component of a movement, the apparatus comprising:
- an accelerometer configured for attachment to a user and configured for measuring components of the acceleration along three orthogonal axes experienced by the user;
a processor configured to;
receive the measured components of the acceleration Ax, Ay, and Az, along three orthogonal axes xa, ya, and za from the accelerometer,estimate an orientation of the accelerometer by calculating an angle θ
between the acceleration and an axis that has the component with the highest magnitude of acceleration by;
calculating the magnitude of each of the components of the acceleration from the measurements indicating the components of the acceleration Ax, Ay, and Az along the three orthogonal axes xa, ya, and za of the accelerometer,identifying the acceleration component with the highest magnitude,determining the angle θ
between the acceleration and the axis with the highest component of acceleration from
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Abstract
The power used by a user in performing the vertical component of a movement is estimated. An accelerometer attached to a user measures the acceleration experienced by the user during movement. A processor configured to receive the measurements of the acceleration from the accelerometer, be attached to the user, estimate the vertical accelerations from the received acceleration measurements, and estimate the power used from the vertical accelerations.
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Citations
7 Claims
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1. An apparatus for estimating power used by a user in performing a vertical component of a movement, the apparatus comprising:
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an accelerometer configured for attachment to a user and configured for measuring components of the acceleration along three orthogonal axes experienced by the user; a processor configured to; receive the measured components of the acceleration Ax, Ay, and Az, along three orthogonal axes xa, ya, and za from the accelerometer, estimate an orientation of the accelerometer by calculating an angle θ
between the acceleration and an axis that has the component with the highest magnitude of acceleration by;calculating the magnitude of each of the components of the acceleration from the measurements indicating the components of the acceleration Ax, Ay, and Az along the three orthogonal axes xa, ya, and za of the accelerometer, identifying the acceleration component with the highest magnitude, determining the angle θ
between the acceleration and the axis with the highest component of acceleration from - View Dependent Claims (2, 3, 4, 5, 6)
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7. A physical therapy apparatus for estimating power used by a user in performing a sit-to-stand (STS) transfer, the apparatus comprising:
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an accelerometer configured for attachment to a user and configured for measuring acceleration experienced by the user during an STS transfer; and a processor configured to; receive the measurements of the acceleration from the accelerometer; estimate vertical accelerations from the received measurements by; estimating an orientation of the accelerometer from the received acceleration measurements; and identifying the vertical accelerations in the received acceleration measurements using the estimated orientation; and wherein the processor is further configured to; based only on the estimated vertical accelerations, a mass of the user, and gravity, estimate the power used during the STS transfer; and compensate for errors in the estimated orientation by computing a variance of a norm of components of the received acceleration measurements over a period of time; and wherein the apparatus further comprises a transceiver configured to receive the estimated power from the processor, and configured to transmit the estimated power to a remote display device to cause the remote display device to display an indication of an instability when the computed variance is greater than a threshold.
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Specification