System and method for detection of freefall with spin using two tri-axis accelerometers
First Claim
1. A system for detecting freefall of an object comprising:
- first and second tn-axis accelerometers A and B located a predetermined fixed distance R apart from each other, each of said accelerometers generating first, second and third acceleration vector signals indicative of a magnitude and direction of acceleration forces imparted thereto;
a processor including a software module for processing said acceleration vector signals and determining therefrom whether said accelerometers are being exposed to centrifugal accelerations in a zero gravity condition resulting from a spin; and
a signal generator for generating a control signal in response to determination by said processor that said accelerometers are undergoing freefall with spin in a common plane.
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Accused Products
Abstract
A system and method detect freefall associated with an object that is spinning or tumbling as it falls. Two tri-axis accelerometers provide inputs to an algorithm that detects the freefall of a spinning object that would not otherwise be detected by a conventional freefall detection system, due to the centrifugal and centripetal forces being placed on the falling object as it spins. The system can be used to detect the freefall of portable devices with onboard memory or hard disk drives, allowing the devices to have time to park the read/write head and reduce the potential of losing data that can be damaged by impact. This freefall detection system may be applied to such portable devices as notebook computers, PDAs, MP3 players, digital cameras, mobile phones and even automobiles.
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Citations
17 Claims
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1. A system for detecting freefall of an object comprising:
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first and second tn-axis accelerometers A and B located a predetermined fixed distance R apart from each other, each of said accelerometers generating first, second and third acceleration vector signals indicative of a magnitude and direction of acceleration forces imparted thereto; a processor including a software module for processing said acceleration vector signals and determining therefrom whether said accelerometers are being exposed to centrifugal accelerations in a zero gravity condition resulting from a spin; and a signal generator for generating a control signal in response to determination by said processor that said accelerometers are undergoing freefall with spin in a common plane. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 17)
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9. A method for detecting freefall of an object comprising:
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locating first and second tri-axis accelerometers A and B a predetermined fixed distance R apart from each other, each of said accelerometers generating first, second and third acceleration vector signals indicative of a magnitude and direction of acceleration forces imparted thereto; processing said acceleration vector signals with a software algorithm and determining therefrom whether said accelerometers are being exposed to centrifugal accelerations in a zero gravity condition resulting from a spin; and generating a control signal in response to determination that said accelerometers are undergoing freefall with spin in a common plane. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification