Vehicle occupant position detector and airbag control system

• US 6,394,490 B2
• Filed: 03/22/2001
• Issued: 05/28/2002
• Est. Priority Date: 08/16/1999
• Status: Expired due to Fees

• Current Assignee: CTS Corporation
• Original Assignee: CTS Corporation
• Inventors: Wills, Michael R., Osmer, William, Blakesley, Patrick B.
• Primary Examiner(s): Johnson, Brian L.
• Assistant Examiner(s): Sliteris, Jacqueline
• Application Number:
  US09/814,904
• Publication Number:
  US 20010010424A1
• Time in Patent Office: 432 Days
• Field of Search: 280/735 180/271 701/45
• US Class Current: 280/735
• CPC Class Codes: B60R 21/01516 using force or pressure sensing means
• CPC Class Codes: B60R 21/0152 using strain gauges
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015

Abstract

An automobile seat occupant sensor and airbag control system for detecting the location and weight of a person in a car and a seat inclination angle. The system includes an airbag and an airbag deployment mechanism for deploying the airbag. Several sensors are fixedly located in a weight path of the vehicle seat. The sensors are located between a seat bottom and a vehicle floor. A controller is connected between the airbag deployment mechanism and the sensors for controlling deployment of the airbag. The controller calculates a center of gravity of the seat occupant, weight of the occupant and a seat inclination angle and uses this information to control deployment of the airbag.

Claims

1. A vehicle airbag control system for sensing the weight and position of an occupant in a vehicle seat and controlling an airbag, comprising:

a) an airbag;

b) airbag deployment means for deploying the airbag;

c) a plurality of sensors, fixedly located in a weight path of the vehicle seat, the sensors located between a seat bottom and a vehicle floor, the sensors further located substantially near an outer perimeter of the seat, each sensor providing an electrical output signal representative of the weight applied by the vehicle occupant at the sensor location, the sensors having strain gauge resistors mounted to a cantilevered beam;

(d) a seat zone located within the outer perimeter of the seat, the seat zone defined as a region of the seat which when the occupant is positioned within the airbag can be safely deployed; and

(e) controller means, connected between the airbag deployment means and the sensors for controlling deployment of the airbag in response to the electrical output signals, the controller means calculating a center of gravity of the seat occupant to locate the position of the occupant in the seat and determining if the center of gravity of the occupant is in a first position located inside the seat zone where the airbag is allowed to deploy or is in a second position located outside the seat zone where the airbag is prevented from deploying, the controller means further calculating a weight of the seat occupant and allowing deployment of the airbag if the occupants weight is above a first magnitude and preventing deployment of the airbag if the occupants weight is below the first magnitude.

2. A method for controlling deployment of an air bag, comprising:

a) providing a plurality of seat weight sensors attached between a vehicle seat and a vehicle floor, the sensors located substantially at an outer perimeter of the seat, each sensor having a plurality of strain gage resistors mounted to a cantilevered beam between the seat and a vehicle floor;

b) providing an airbag controller;

c) seating an occupant into the seat;

d) generating a plurality of electrical signals from the seat weight sensors proportional to the weight and location of the seat occupant;

e) providing the electrical signal to an airbag controller that is connected to the airbag;

f) calculating a center of gravity and weight of the seat occupant from the electrical signals to locate the position of the occupant in the seat;

g) determining if the center of gravity of the occupant is in a first position within the outer perimeter of the seat where the airbag is allowed to deploy or is in a second position outside the outer perimeter of the seat where the airbag is prevented from deploying; and

h) determining if the occupant weight is above a first magnitude where the airbag is allowed to deploy or is below the first magnitude where the airbag is prevented from deploying.

3. The method for controlling deployment of an air bag according to claim 2 wherein, the airbag is deployed with maximum force, if a heavy occupant is detected in the seat and the airbag is deployed at less than maximum force, if a light occupant is detected in the seat.

4. The method for controlling deployment of an air bag according to claim 2, further comprising:

determining if the center of gravity is located outside the vehicle seat.

5. A control system for controlling an airbag, the control system controlling the airbag in relation to the weight and position of a seat occupant, comprising:

a) an airbag;

b) an airbag inflator, connected to the air bag, for inflating an airbag;

c) a sensor, attached to a seat, for sensing a weight of the seat occupant at a sensor location, the sensor located substantially near an outer perimeter of the seat and providing an electrical output signal representative of the weight applied by the vehicle occupant at the sensor location, the sensor including a plurality of strain gauge resistors mounted to a vertically oriented base;

d) a processor connected to the sensors and to the airbag inflation means;

e) software operative on the processor for;

e1) calculating the weight of the seat occupant;

e2) determining if the weight of the seat occupant is less than a first magnitude;

e3) preventing actuation of the airbag inflation means, if the weight of the seat occupant is less than a first magnitude; and

e4) allowing actuation of the airbag inflation means, if the weight of the seat occupant is greater than the first magnitude;

f) calculating a center of gravity of the seat occupant;

g) determining if the center of gravity is inside or outside a first area, the first area defined as being substantially within the outer perimeter of the seat;

h) preventing actuation of the airbag inflation means, if the center of gravity is outside the first area; and

i) allowing actuation of the airbag inflation means, if the center of gravity is inside the first area.