Adaptive pressure based weight estimation system for a vehicle occupant
First Claim
1. A system for estimating the weight of an occupant of a seat in a motor vehicle, the seat having a foam cushion bottom, the apparatus comprising:
- a pressure sensor disposed in the foam cushion bottom so as to be responsive to the weight of the occupant, the sensor providing a pressure signal output;
a temperature sensor for sensing a temperature in proximity to said pressure sensor, and providing a temperature signal output; and
a controller for estimating the weight of the occupant based on the pressure signal output, the temperature signal output, and a calibrated value corresponding to a pressure signal output when the seat is vacant, the controller including means for adjusting the calibrated value downward in response a pressure signal output that remains lower than the calibrated value for at least a predetermined time, the adjustment being determined as a predetermined fraction of a difference between the pressure signal output and the calibrated value.
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Accused Products
Abstract
An improved pressure-based weight estimation system that includes an adaptive technique for reliably and accurately determining the vacant, or unoccupied, seat pressure. The vacant seat pressure is initially determined by a factory calibration procedure, and is thereafter suitably updated by an adaptive learning algorithm based on temperature, time, and the measured pressure. If the seat temperature is within a normal range, and the measured pressure remains at least a predetermined amount below the calibrated vacant seat pressure for at least a predetermined time, a fraction of the difference between the measured and calibrated values is subtracted from the calibrated value to form a new calibration value. The predetermined difference amount determines the sensitivity of the control, and the predetermined time prevents adaptive correction of the calibration value due to transient pressure conditions.
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Citations
12 Claims
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1. A system for estimating the weight of an occupant of a seat in a motor vehicle, the seat having a foam cushion bottom, the apparatus comprising:
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a pressure sensor disposed in the foam cushion bottom so as to be responsive to the weight of the occupant, the sensor providing a pressure signal output; a temperature sensor for sensing a temperature in proximity to said pressure sensor, and providing a temperature signal output; and a controller for estimating the weight of the occupant based on the pressure signal output, the temperature signal output, and a calibrated value corresponding to a pressure signal output when the seat is vacant, the controller including means for adjusting the calibrated value downward in response a pressure signal output that remains lower than the calibrated value for at least a predetermined time, the adjustment being determined as a predetermined fraction of a difference between the pressure signal output and the calibrated value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A system for estimating the weight of an occupant of a seat in a motor vehicle, the seat having a foam cushion bottom, the apparatus comprising:
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a pressure sensor disposed in the foam cushion bottom so as to be responsive to the weight of the occupant, and providing a pressure signal output, the signal output having a reference value when the seat is vacant; a temperature sensor for sensing a temperature in proximity to said pressure sensor, and providing a temperature signal output; and a controller for estimating the weight of the occupant by compensating the pressure signal output based on the sensed temperature, and comparing the compensated pressure signal output to a threshold based on said reference value, and for periodically adjusting the reference value downward in response a pressure signal output that remains lower than the reference value for at least a predetermined time, the adjustment being determined as a predetermined fraction of a difference between the pressure signal output and the reference value. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification