Racket sport inertial sensor motion tracking analysis
First Claim
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1. A racket system comprising:
- an inertial sensor comprising an accelerometer with three degrees of freedom in measurement of acceleration of a racket and a gyro sensor with three degrees of freedom in measurement of angular rotation of the racket;
a processor in communication with the inertial sensor, the processor configured to;
generate time histories describing acceleration and rotation of the racket based on signals from the accelerometer and the gyro sensor;
identify pulse features in the time histories;
segment the time histories into individual stroke profiles based on time matching of the pulse features, wherein the acceleration and rotation of the racket define characteristics of the individual stroke profiles;
generate stroke trajectories based on the individual stroke profiles, the stroke trajectories describing position, velocity and orientation of the racket measured during stroke interactions; and
determine aerodynamic forces and moments acting on the racket based on the stroke trajectories; and
a memory device in communication with the processor, the memory device configured to store the individual stroke profiles;
wherein the individual stroke profiles are divided into stroke classes based on the corresponding characteristics, the stroke classes defining a stroke repertoire.
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Abstract
A system for a racket comprises an inertial sensor for coupling to the racket, a processor connected to the inertial sensor, and a memory device connected to the processor. The inertial sensor includes an accelerometer array with three degrees of freedom in acceleration and a gyro array with three degrees of freedom in rotation. The processor is configured to generate stroke profiles describing acceleration and rotation of the racket based on signals from the accelerometer and the gyro arrays, and the memory device is configured to store the stroke profiles.
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Citations
28 Claims
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1. A racket system comprising:
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an inertial sensor comprising an accelerometer with three degrees of freedom in measurement of acceleration of a racket and a gyro sensor with three degrees of freedom in measurement of angular rotation of the racket; a processor in communication with the inertial sensor, the processor configured to; generate time histories describing acceleration and rotation of the racket based on signals from the accelerometer and the gyro sensor; identify pulse features in the time histories; segment the time histories into individual stroke profiles based on time matching of the pulse features, wherein the acceleration and rotation of the racket define characteristics of the individual stroke profiles; generate stroke trajectories based on the individual stroke profiles, the stroke trajectories describing position, velocity and orientation of the racket measured during stroke interactions; and determine aerodynamic forces and moments acting on the racket based on the stroke trajectories; and a memory device in communication with the processor, the memory device configured to store the individual stroke profiles; wherein the individual stroke profiles are divided into stroke classes based on the corresponding characteristics, the stroke classes defining a stroke repertoire. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method comprising:
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sensing acceleration of a racket with an inertial sensor coupled thereto, the inertial sensor comprising an accelerometer with three degrees of freedom in measurement of acceleration of the racket; sensing angular velocity of the racket with the inertial sensor, the inertial sensor further comprising a gyro sensor with three degrees of freedom in measurement of angular rotation of the racket; generating time histories with a processor in communication with the inertial sensor, the time histories describing the acceleration and angular velocity of the racket; identifying pulse features within the time histories; generating individual stroke profiles by segmenting the time histories based on time matching of the pulse features, wherein the acceleration and angular velocity of the racket define characteristics of the individual stroke profiles; storing the individual stroke profiles in memory, wherein the individual stroke profiles are divided into stroke classes based on the corresponding characteristics, the stroke classes defining a stroke repertoire; estimating state vectors for converting the individual stroke profiles into stroke trajectories representing reconstructed racket flight paths, the state vectors describing position, velocity and orientation of the racket during stroke interactions; and determining impact forces and angular momentum transfer from the racket to a ball and from the ball to the racket during the stroke interactions, wherein a ball strike causes a simultaneous change in linear and angular momentum of the racket. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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22. A racket system comprising:
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an inertial sensor coupled to a racket, the inertial sensor having three degrees of freedom in acceleration and three degrees of freedom in angular rotation; a processor configured to; generate time histories describing acceleration and rotation of the racket based on signals from the inertial sensor;
identify pulse features in the time histories;segment the time histories into individual stroke profiles based on time matching of the pulse features, wherein the acceleration and rotation of the racket define characteristics of the individual stroke profiles; generate stroke trajectories based on the individual stroke profiles, the stroke trajectories describing position, velocity and orientation of the racket measured during stroke interactions, wherein generating stroke trajectories further comprises reconstructing external forces and moments acting on the racket system during the stroke interactions; and a cueing device coupled to the processor, the cueing device configured to generate realtime audio, haptic or visual player feedback based on conformance of the individual stroke profiles to a stroke model. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification