Signal processing in a vehicle weight classification system

• US 20010025730A1
• Filed: 02/23/2001
• Published: 10/04/2001
• Est. Priority Date: 02/25/2000
• Status: Active Grant

• Current Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Morell, Scott, Cook, Charles R. Jr., Reich, Daniel, Belau, Horst, Lichtinger, Harald, Swart, Marten
• Granted Patent: US 6,677,538 B2
• Time in Patent Office: Days
• US Class Current: 177/25.13
• 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 2/0024 for identifying, categorising or investigation of the occupant or object on the seat
• 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: B60N 2230/30 Signal processing of sensor data
• 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

A vehicle weight classification system recognizes the various factors that influence system performance. Some of the factors are compensated for using analog signal processing circuitry or techniques. Other factors are compensated for using digital signal processing techniques. The unique combination of analog and digital approaches, rather than pure analog or pure digital, provides an effective solution at addressing the various factors that influence signals and system performance in a vehicle weight classification system while keeping the cost and complexity of the system within acceptable limits.

Claims

1. A method of compensating for various influences on a sensor signal that provides an indication of a weight of a seat occupant in a vehicle supplemental restraint system, comprising the steps of:

(A) identifying a plurality of factors that influence the sensor signal;

(B) processing the signal using analog signal processing to compensate for at least one of the factors; and

(C) processing the signal using digital signal processing to compensate for at least one other of the factors.

2. The method of

claim 1

, wherein the factors include temperature, sensor offset, signal strength, signal spread, and vehicle seat parameters.

3. The method of

claim 2

, including compensating for the temperature factor using the analog signal processing.

4. The method of

claim 2

, including compensating for the sensor offset factor using the analog signal processing.

5. The method of

claim 2

, including compensating for the signal strength using the digital signal processing.

6. A vehicle weight classification system, comprising:

a plurality of sensors that provide an electrical signal indicative of the weight of a seat occupant;

a signal conditioner associated with each sensor having a first portion that utilizes an analog signal to compensate for at least one factor that influences the sensor signal and a second portion that utilizes a digital signal to compensate for at least one other factor that influences the sensor signal; and

a controller that receives the conditioned signal and controls a supplemental restraint device.

7. The system of

claim 6

, wherein the signal conditioning module first portion compensates for temperature influences on the sensor signal.

8. The system of

claim 6

, wherein the signal conditioning module first portion compensates for sensor offset factors.

9. The system of

claim 6

, wherein the signal conditioner second portion compensates for signal strength.