Diagnostic method for a seat load

• US 20030051564A1
• Filed: 08/16/2002
• Published: 03/20/2003
• Est. Priority Date: 02/08/1999
• Status: Active Grant

• Current Assignee: Joyson Safety Systems Japan K.K.
• Original Assignee: Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Inventors: Aoki, Hiroshi
• Granted Patent: US 6,817,254 B2
• Time in Patent Office: Days
• US Class Current: 73/862.391
• 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: 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

To provide a diagnostic method of a seat load measuring apparatus for detecting an abnormality of the seat load measuring apparatus, outputs of load sensors 1R, 1L are inputted into a differential amplifier 4 through a multiplexer 3, converted into digital signals by a A/D converter 5, and then inputted into the MPU 6. An offset correction amount is added into the input of the differential amplifier 3 from the MPU 6 through a D/A converter 10. First, the output of the differential amplifier 4 is measured in a state in which no load is applied to a seat and a value thus measured is assumed as X1. After a predetermined load is applied to the seat, the output of the differential amplifier 4 is measured and a value thus measured is assumed as Y1. It is judged that a difference between X1 and Y1 is in a predetermined range between A1 and B1. When the difference between X1 and Y1 is not in the range between A1 and B1, an alarm indicating abnormality is emitted.

Claims

1. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat and an amplifier for amplifying signals from the load sensors, the diagnostic method comprising the steps of comparing information from the seat load measuring apparatus in a state in which the vehicle seat is not mounted on the load sensors to information from the seat load measuring apparatus in a state in which the vehicle seat is mounted on the load sensors, and thereby judging whether the seat load measuring apparatus normally functions.

8. A diagnostic method as claimed in any one of claims 1 through 7, wherein at least an output of said amplifier is used as the information from said seat load measuring apparatus.

9. A diagnostic method as claimed in any one of claims 1 through 8, wherein the seat load measuring apparatus has a dead weight calibrating portion, wherein at least an output of the dead weight calibrating portion in each of said states is used as the information from said seat load weight measuring apparatus.

2. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises a plurality of load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat and a plurality of amplifiers for amplifying signals from the load sensors, the diagnostic method comprising the steps of comparing the respective pieces of information from seat load measuring portions corresponding to the respective load sensors when the load sensors are assembled in seat portions, and thereby judging whether the seat load measuring apparatus functions normally.

3. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat and an amplifier for amplifying signals from the load sensors, the diagnostic method comprising the steps of comparing information from the seat load measuring apparatus in a state in which the vehicle seat is mounted on the load sensors but before installation to the vehicle body to information from the seat load measuring apparatus after the installation to the vehicle, and thereby judging whether the seat load measuring apparatus functions normally.

4. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises a plurality of load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat and a plurality of amplifiers for amplifying signals from the load sensors, the diagnostic method comprising the steps of comparing the respective pieces of information from seat load measuring portions corresponding to the respective load sensors when seat portions with the load sensors are installed to a vehicle body, and thereby judging whether the seat load measuring apparatus normally functions.

5. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat and an amplifier for amplifying signals from the load sensors, the diagnostic method comprising the steps of comparing information from the seat load measuring apparatus in a state in which no load is applied to the load sensors to information from the seat load measuring apparatus in a state in which a predetermined load is applied to the load sensors, and thereby judging whether the seat load measuring apparatus normally functions.

6. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat and an amplifier for amplifying signals from the load sensors, the diagnostic method comprising the steps of comparing information from the seat load measuring apparatus in a state in which no load is applied to the vehicle seat to information from the seat load measuring apparatus in a state in which a predetermined load is applied to the vehicle seat, and thereby judging whether the seat load measuring apparatus normally functions.

7. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat and an amplifier for amplifying signals from the load sensors, the diagnostic method comprising the steps of comparing a sensitivity of the seat load measuring apparatus before the vehicle seat is mounted on the load sensors to a sensitivity of the seat load measuring apparatus after the vehicle seat is mounted on the load sensors, and thereby judging whether the seat load measuring apparatus normally functions.

10. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat, an amplifier for amplifying signals from the load sensors, and a dead weight calibrating portion, the diagnostic method comprising the steps of making an initial dead weight calibration in a state in which the seat is mounted on the load sensors, storing a correction amount for this calibration as an initial correction amount, comparing the initial correction amount to a correction amount for another dead weight calibration made after the initial dead weight calibration, and thereby judging whether the seat load measuring apparatus normally functions.

11. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat, an amplifier for amplifying signals from the load sensors, and a dead weight calibrating portion, the diagnostic method comprising the steps of making an initial dead weight calibration in a state in which the seat is not mounted on the load sensors, storing a correction amount for this calibration as an initial correction amount, comparing the initial correction amount to a correction amount for another dead weight calibration made after the initial dead weight calibration, and thereby judging whether the seat load measuring apparatus normally functions.

12. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat, an amplifier for amplifying signals from the load sensors, and a dead weight calibrating portion, the diagnostic method comprising the steps of making a dead weight calibration in a state in which the seat is mounted on the load sensors, storing an output of the seat load measuring apparatus as an initial value, comparing the initial value to an output of the seat load measuring sensor measured when no object is on the seat, and thereby judging whether the seat load measuring apparatus normally functions.

13. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat, an amplifier for amplifying signals from the load sensors, and a dead weight calibrating portion, the diagnostic method comprising the steps of making a dead weight calibration in a state in which the seat is not mounted on the load sensors, storing a correction amount for this calibration as a first correction amount A, making a dead weight calibration again in a state in which the seat is mounted on the load sensors, storing a correction amount for this calibration as a second correction amount B, measuring the load applied on the seat by using the second correction amount B to output a measured value as the output of the load measuring apparatus, measuring the load applied on the seat by using the first correction amount A, and emitting an alarm or performing a compensating calculation when the value measured using the first correction amount A exceeds a predetermined value.

14. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat, an amplifier for amplifying signals from the load sensors, and a dead weight calibrating portion, the diagnostic method comprising the steps of making a dead weight calibration in a state in which the seat is not mounted on the load sensors and a predetermined load is applied to the load sensors, storing a correction amount for this calibration as a first correction amount C, making a dead weight calibration again in a state in which the seat is mounted on the load sensors, storing a correction amount for this calibration as a second correction amount D, measuring a load applied on the seat by using the second correction amount D to output a measured value as the output of the load measuring apparatus, measuring the load-applied on the seat by using the first correction amount C, and emitting an alarm or performing a compensating calculation when the value measured using the first correction amount C exceeds a predetermined value.

15. A diagnostic method for a seat load measuring apparatus for measuring the load applied on a vehicle seat, wherein the seat load measuring apparatus comprises load sensors for detecting the weight of the vehicle seat itself and the weight of an object on the vehicle seat, an amplifier for amplifying signals from the load sensors, and a sensitivity calibrating portion for the load sensors, the diagnostic method comprising the steps of making an initial sensitivity calibration storing a sensitivity correction amount for this calibration, comparing the sensitivity correction amount to a sensitivity correction amount for another sensitivity calibration made after the initial sensitivity calibration, and thereby judging whether the seat load measuring apparatus normally functions.