Method for determining an occupancy status of a seat and corresponding determination system

Patent metadata

Field	Value
Publication number	US-12030407-B2
Application number	US-202117534746-A
Country	US
Kind code	B2
Filing date	Nov 24, 2021
Priority date	Nov 27, 2020
Publication date	Jul 9, 2024
Grant date	Jul 9, 2024

Abstract

The present disclosure relates to a method for determining the occupancy status of a seat of a motor vehicle, the method being implemented by a determination system comprising a seat, six interdigitated capacitive sensors, and a controller comprising a reference capacitance value and a threshold value for each interdigitated capacitive sensor, the method comprising a step of measuring three capacitance values for each interdigitated capacitive sensor, the following steps being implemented by the controller for the measured capacitance values: calculating a resulting capacitance value based on the measured capacitance values, calculating the difference between the resulting capacitance value and the reference capacitance value, comparing the calculated difference to the threshold value, determining the occupancy status of the seat, based on the result of the comparison.

First claim

The invention claimed is:

1. A method for determining the occupancy status of a seat of a motor vehicle, the method being implemented by a determination system comprising a seat, at least six interdigitated capacitive sensors carried by the seat, and a controller connected to the interdigitated capacitive sensors, the controller comprising a memory comprising a database, the database comprising at least one reference capacitance value and one threshold value for each interdigitated capacitive sensor, the method comprising measuring at least three capacitance values for each interdigitated capacitive sensor, the following steps being implemented by the controller for the capacitance values measured by each interdigitated capacitive sensor:
calculating a resulting capacitance value based on at least two measured capacitance values,
calculating the difference between the resulting capacitance value and the reference capacitance value,
comparing the calculated difference to the threshold value, and
determining the occupancy status of the seat, based on the result of the comparison.

2. The method of claim 1 , further comprising determining a minimum capacitance value and a maximum capacitance value among the measured capacitance values, and wherein calculating the resulting capacitance value includes calculating an average capacitance value based on the minimum capacitance value and maximum capacitance value.

3. The method of claim 1 , wherein the database further comprises second capacitance variation ranges defined for the interdigitated capacitive sensors, each second variation range being defined for a capacitance sensor, the second variation ranges being representative of a status of occupied by a thing, an animal, or a child, and wherein the method further comprises, for each interdigitated capacitive sensor, comparing the calculated difference to the second variation range, the determined occupancy status being a status of occupied by a thing, an animal, or a child, when the average capacitance values calculated for each interdigitated capacitive sensor are comprised within the second capacitance variation ranges.

4. The method of claim 3 , wherein the database further comprises at least two capacitance variation subdomains defined for the interdigitated capacitive sensors and respectively, each capacitance variation subdomain being representative of a range of child age values, and wherein the method further comprises:
comparing the calculated differences to at least two capacitance variation subdomains, and
determining a range of child age values, based on the result of the comparison.

5. The method of claim 1 , wherein calculating the resulting capacitance value includes calculating an average capacitance value based on the at least two measured capacitance values.

6. The method according to claim 5 , wherein the database further comprises second capacitance variation ranges defined for the interdigitated capacitive sensors, each second variation range being defined for a capacitance sensor, the second variation ranges being representative of a status of occupied by a thing, an animal, or a child, and wherein the method further comprises, for each interdigitated capacitive sensor, comparing the calculated difference to the second variation range, the determined occupancy status being a status of occupied by a thing, an animal, or a child, when the average capacitance values calculated for each interdigitated capacitive sensor are comprised within the second capacitance variation ranges.

7. The method of claim 1 , wherein the database further comprises first capacitance variation ranges defined for the interdigitated capacitive sensors, each first variation range being defined for an interdigitated capacitive sensor, the first variation ranges being representative of a status of occupied by a person, and wherein the method further comprises, for each interdigitated capacitive sensor:
comparing the calculated difference to the first variation range, the determined occupancy status being the status of occupied by a person when the differences calculated for each interdigitated capacitive sensor are comprised within the first variation ranges.

8. The method of claim 7 , wherein the database further comprises at least two capacitance variation subdomains defined for each interdigitated capacitive sensor, each capacitance variation subdomain being representative of a morphological type of a person, and wherein the method comprises:
comparing the calculated differences to at least two capacitance variation subdomains; and
determining a morphological type of the person sitting in the seat, based on the result of the comparison.

9. The method of claim 1 , wherein the method includes measuring at least three capacitance values for each interdigitated capacitive sensor each time a door of the motor vehicle is opened or unlocked.

10. The method of claim 1 , wherein the method includes measuring at least three capacitance values for each interdigitated capacitive sensor each time a door of the motor vehicle is closed or locked.

11. The method of claim 1 , wherein measuring at least three capacitance values for each interdigitated capacitive sensor lasts less than three seconds.

12. The method of claim 11 , wherein measuring at least three capacitance values for each interdigitated capacitive sensor lasts less than one second.

13. The method of claim 1 , wherein the memory comprises, for each interdigitated capacitive sensor, a curve representing average capacitance values as a function of time, and a determined deviation, and wherein the method further comprises the following steps, implemented, for each interdigitated capacitive sensor:
determining a minimum capacitance value and a maximum capacitance value among the measured capacitance values,
selecting a determined number of last capacitance values of the curve, the determined number being between 5 and 20,
calculating the difference between the minimum capacitance value and the selected values,
calculating the difference between the maximum capacitance value and the selected values,
if at least one of the differences is greater than the deviation, the method returns to the measurement step,
if the differences are less than the deviation, the method continues via the step of calculating a resulting capacitance value.

14. The method of claim 13 , wherein, if the differences are less than the deviation, the method comprises saving the average capacitance value in the curve.

15. The method of claim 13 , wherein the curve comprises a capacitance value measured after the manufacture of the seat and before its mounting in the vehicle, a capacitance value measured after the mounting of the seat in the motor vehicle, and a capacitance value measured before its first use.

16. The method of claim 13 , wherein the determined number is equal to 10.

17. A system for determining the occupancy status of a seat of a motor vehicle, the system comprising:
a motor vehicle seat comprising:
a seating portion having a receiving face intended to accommodate a person, the receiving face being divided into a front area and a rear area, the front area and the rear area being located one on either side of a transverse central plane of the seat,
a backrest having a receiving face intended to accommodate the back of a person, the backrest being hinged to the seating portion, the rear area of the receiving face of the seating portion being adjacent to the backrest,
only three interdigitated capacitive sensors carried by the receiving face of the ba

Assignees

• Faurecia Sieges Dautomobile

Inventors

• Baudu Samuel
• Balde Mamadou
• Le Roux Stéphane
• Rouchou Mohamed

Classifications

• B60R21/01516 Primary

  using force or pressure sensing means · CPC title

• B60N2210/12

  Capacitive; Electric field · CPC title

• B60N2/003

  characterised by the sensor mounting location in or on the seat · CPC title

• B60N2210/40

  Force or pressure sensors · CPC title

• B60N2/0026

  for distinguishing between humans, animals or objects · CPC title