Tire and suspension warning and monitoring system
First Claim
1. A method of monitoring tire imbalance comprising:
- sensing and analyzing changes to matched-filtered vibrations of a tire/wheel assembly, and determining tire imbalance based on said sensing and analyzing, wherein said sensing and analyzing comprises;
sensing at least one acceleration of the wheel to provide acceleration signals;
collecting a predetermined number of acceleration signal samples;
transforming and normalizing the samples;
computing a rotational frequency of the wheel from the normalized samples;
computing a harmonic frequency of the rotational frequency of the wheel;
summing frequency components around the harmonic frequency; and
comparing summed frequency components with a previously stored baseline value.
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Abstract
A tire and suspension monitoring and warning system consisting of a set of multi-function sensors that monitor and warn of a failure mode. The system monitors and warns for tire imbalance, tire tread wear, and shock absorbers for a tire attached to a vehicle. The monitoring and warning system includes one axial, radial, and lateral acceleration measurement of the wheel to provide acceleration signal sample power. For tire imbalance, signal sample power in the second harmonic of the tire rotational frequency is compared to that of the first harmonic. For tire tread wear, average signal sample power within a second frequency range is compared to a previously stored baseline value. For shock absorber performance, a sum of all frequency components in a second predetermined frequency range is compared to a baseline value.
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Citations
14 Claims
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1. A method of monitoring tire imbalance comprising:
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sensing and analyzing changes to matched-filtered vibrations of a tire/wheel assembly, and determining tire imbalance based on said sensing and analyzing, wherein said sensing and analyzing comprises;
sensing at least one acceleration of the wheel to provide acceleration signals;
collecting a predetermined number of acceleration signal samples;
transforming and normalizing the samples;
computing a rotational frequency of the wheel from the normalized samples;
computing a harmonic frequency of the rotational frequency of the wheel;
summing frequency components around the harmonic frequency; and
comparing summed frequency components with a previously stored baseline value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for monitoring tire imbalance comprising:
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a sensor to sense changes to matched-filtered vibrations of a tire/wheel assembly; and
a processing device to analyze the sensed changes to the matched-filtered vibrations and to determine tire imbalance based on the sensed changes, wherein said sensor senses at least one acceleration of the wheel and provides acceleration signals corresponding thereto; and
said processing device comprises;
a collector for collecting a predetermined number of acceleration signals samples;
a transformer and normalizer for transforming and normalizing the samples within a first predetermined frequency range;
a first calculator for calculating a rotational frequency of the wheel from the transformed and normalized samples;
a second calculator for calculating a harmonic frequency of the wheel from the calculated rotational frequency of the wheel;
a comparator for comparing the harmonic frequency with a previously stored baseline value; and
an output circuit for outputting a signal indicative of the comparison results of the comparator. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification