APPARATUS FOR CLASSIFYING VEHICLE OCCUPANT

• US 20090126513A1
• Filed: 01/10/2008
• Published: 05/21/2009
• Est. Priority Date: 11/21/2007
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group), Kia Motors Corporation (Kia Corp.)
• Inventors: Park, Chun Seok, Yoo, Jae Haeng
• Granted Patent: US 7,614,314 B2
• Time in Patent Office: Days
• US Class Current: 73/862.626
• CPC Class Codes: B60R 21/01532 using electric or capacitive field sensors

Abstract

An apparatus for classifying a vehicle occupant to determine whether to deploy an airbag is disclosed. The classification apparatus includes a sensor which is installed in a seat of a vehicle and is supplied with AC power, the sensor having a sensing conductor and a guard conductor electrically connected to each other, with an insulator interposed therebetween. A controller compares an imaginary current value, attributable to variation in capacitance of the sensor, measured on an output side of the sensor, and a real current value, attributable to variation in resistance of the sensor, with preset threshold values, thus classifying an occupant who is sitting in the seat. According to the classification apparatus, even if moisture permeates into a seat, an occupant can be precisely classified using the real current value and the imaginary current value.

Claims

1. An apparatus for classifying a vehicle occupant, comprising:

a capacitive sensor installed in a seat of a vehicle and supplied with Alternating Current (AC) power,

a current detector connected to an output side of the sensor; and

a controller for measuring an imaginary current value attributable to variation in capacitance of the sensor and a real current value attributable to variation in resistance of the sensor, using the current detector, and for classifying an occupant sitting in the seat by comparing the measured imaginary current value with a threshold value;

wherein the controller is configured to determine the threshold value based on the measured real current value and a threshold data set including predetermined pairs of reference imaginary current values and reference real current values, and wherein the measured real current value acts as a determining factor for the threshold value, and wherein the threshold value corresponds to a companion reference imaginary current value being paired with a companion reference real current value corresponding to the measured real current value.

2. The apparatus according to claim 1, wherein the controller measures output current values of the sensor at different time points, thus obtaining the imaginary current value and the real current value of the output current value.

3. The apparatus according to claim 1, wherein the controller measures output current values of the sensor corresponding to a time point at which an amplitude of an input voltage of the sensor is a peak value, and a time point at which the amplitude thereof is zero, thus obtaining the imaginary current value and the real current value of the output current value.

5. The apparatus according to claim 1, wherein the preset threshold data set includes experimental values previously derived from imaginary current values and real current values, which are measured while a type of occupant is changed according to a degree of wetting of the seat, and is variable depending on the degree of wetting of the seat.

8. The apparatus according to claim 1, wherein the capacitive sensor having a sensing conductor and a guard conductor electrically connected to each other with an insulator interposed therebetween.

9. The apparatus according to claim 1, further comprising a diode interposed between the sensing conductor and the guard conductor, and wherein the diode is configured so that current flows only in a forward direction from the guard conductor to the sensing conductor.

4. (canceled)

6-7. -7. (canceled)

10. A method for classifying a vehicle occupant, comprising

supplying Alternating Current (AC) power to a capacitive sensor installed in a seat of a vehicle;

measuring a imaginary current value attributable to variation in capacitance of the sensor and a real current value attributable to variation in resistance of the sensor, using a current detector connected to an output side of the sensor;

determining a threshold value based on the measured real current value and a threshold data set including predetermined pairs of reference imaginary current values and reference real current values, wherein the measured real current value acts as a determining factor for the threshold value and wherein the threshold value corresponds to a companion reference imaginary current value being paired with a companion reference real current value corresponding to the measured real current value; and

classifying an occupant sitting in the seat by comparing the measured imaginary current value with the threshold value.