Signal processing in a vehicle classification system

• US 6,891,111 B1
• Filed: 08/31/2000
• Issued: 05/10/2005
• Est. Priority Date: 02/04/1994
• Status: Expired due to Fees

• Current Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Morell, Scott, Cook, Charles R. Jr.
• Primary Examiner(s): Gibson, Randy W.
• Application Number:
  US09/651,714
• Time in Patent Office: 1,713 Days
• Field of Search: 177/144, 177/210.R, 341/169, 280/735, 180/273
• US Class Current: 177/144
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/0025 by using weight measurement
• CPC Class Codes: B60N 2/0035 characterised by the sensor data transmission, e.g. wired connections or wireless transmitters therefor; characterised by the sensor data processing, e.g. seat sensor signal amplification or electric circuits for providing seat sensor information
• CPC Class Codes: B60N 2210/42 Strain gauges
• 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
• CPC Class Codes: H03M 1/504 using pulse width modulation

Abstract

A vehicle weight classification system determines the weight of a seat occupant for controlling airbag deployment. Strain gauge sensors preferably provide signals having a magnitude that is indicative of the weight of the seat occupant. A converting module converts the sensor signals into timing information. A microprocessor, which includes a timer module, receives the timing information and makes a weight determination from the timing information.

Claims

1. A method of determining weight information in a vehicle weight classification system having at least one sensor that generates a signal indicative of weight and a controller that communicates with the sensor, comprising the steps of:

(A) generating a signal indicative of weight;

(B) determining timing information from the signal of step (A); and

(C) determining the weight information from the timing information of step (B), using the controller.

2. The method of claim 1, wherein step (A) is performed using a strain gauge sensor and the magnitude of the signal is indicative of weight.

3. The method of claim 1, wherein step (B) includes generating a pulse width modulated signal that has a width that is indicative of the magnitude of the analog signal.

4. The method of claim 3, wherein step (C) includes using the width of the pulse width modulated signal to derive the weight information.

5. The method of claim 4, wherein step (C) is performed using a timer in the controller.

6. The method of claim 1, including amplifying the signal of step (A), comparing the amplified signal to a reference signal and determining a time that the amplified signal has a chosen relationship to the reference signal to thereby determine the timing information from the signal of step (A).

7. The method of claim 1, wherein step (B) is performed using a pulse width modulating circuit and step (C) is performed using a timer on the controller.

8. A vehicle weight classification system, comprising:

at least one sensor that provides a signal indicative of a weight;

a converting module that converts the sensor signal into timing information; and

a controller that has a timer module that communicates with the converting module such that the controller determines the weight sensed by the sensor from the timing information.

9. The system of claim 8, wherein the sensor comprises a strain gauge sensor supported on a vehicle seat, the sensor producing a signal responsive to a weight on the seat, the signal having a magnitude that is indicative of the weight.

10. The system of claim 8, wherein the converting module includes an amplifier that amplifies the signal from the sensor, a reference portion that generates a reference signal and a comparator portion that compares the amplified signal to the reference signal.

11. The system of claim 10, wherein the comparator portion produces a signal that has timing information that is indicative of a relationship between the amplified sensor signal and the reference signal.

12. The system of claim 11, wherein the controller timer module receives the comparator portion signal and the controller interprets timing information from the comparator portion signal and determines the weight from the timing information.