Method and apparatus for recording the rotation angle of a vehicle

• US 7,933,697 B2
• Filed: 07/24/2009
• Issued: 04/26/2011
• Est. Priority Date: 07/24/2008
• Status: Active Grant

• Current Assignee: Veoneer Sweden Safety Systems AB
• Original Assignee: Autoliv AB (Autoliv Incorporated)
• Inventors: Fukushima, Shinya, Oda, Makoto
• Primary Examiner(s): Camby; Richard M.
• Application Number:
  US12/508,919
• Publication Number:
  US 20100023208A1
• Time in Patent Office: 641 Days
• Field of Search: 701/29, 701/35, 701/31, 701/36, 701/70, 701/207, 180/271, 180/274, 340/436, 340/438
• US Class Current: 701/35
• CPC Class Codes: G07C 5/085 using electronic data carriers

Abstract

An apparatus for recording the rotation angle of a vehicle comprises an angular velocity sensor adapted to measure an angular velocity ω of the vehicle, an integrator adapted to integrate the measured angular velocity ω across a predetermined unit of time Δt to calculate a differential rotation angle Δα in unit of time Δt, a ring buffer adapted to store the differential rotation angles Δαan acceleration sensor adapted to detect that an accident occurred with the vehicle, and a nonvolatile recording device adapted to record, when an accident is detected by the acceleration sensor, the differential rotation angles Δα_M . . . Δα_M+N−1 stored in the ring buffer, across a predetermined recording time T before and after the accident.

Claims

1. A method for recording the rotation angles of a vehicle comprising the steps of:

measuring an angular velocity of the vehicle;

integrating the measured angular velocity across a predetermined unit of time to calculate a differential rotation angle in unit of time;

storing the differential rotation angle in a buffer; and

when a vehicle accident is detected, recording in a recording device a plurality of differential rotation angles stored in the buffer across a predetermined recording time before and after the accident.

2. The method for recording rotation angles of a vehicle according to claim 1, further comprising the steps of:

reading the plurality of differential rotation angles recorded in the recording device; and

subsequently integrating the plurality of differential rotation angles to calculate a total rotation angle at an arbitrary point in time within the recording time.

3. The method for recording the rotation angles of a vehicle according to claim 1, further comprising the steps of:

detecting whether or not an airbag of the vehicle has been deployed; and

disabling replacement of the plurality of differential rotation angles recorded in the recording device if the airbag has been deployed.

9. The method for recording the rotation angles of a vehicle according to claim 1, wherein the plurality of differential rotation angles include the differential rotation angle.

4. An apparatus for recording rotation angles of a vehicle comprising:

an angular velocity sensor for measuring an angular velocity of the vehicle;

an integrator for integrating the measured angular velocity across a predetermined unit of time to calculate a differential rotation angle in unit of time;

a buffer for storing a plurality of differential rotation angles;

an accident sensor for detecting vehicle accidents; and

a recording device for recording, when an accident is detected by the accident sensor, the plurality of differential rotation angles stored in the buffer across a predetermined recording time before and after the accident.

5. The apparatus for recording rotation angles of a vehicle according to claim 4, further comprising:

a reader for reading the plurality of differential rotation angles recorded in the recording device; and

an integrator for subsequently integrating the plurality of differential rotation angles to calculate a total rotation angle at an arbitrary point in time within the recording time.

6. The apparatus for recording rotation angles of a vehicle according to claim 4, wherein the buffer is a ring buffer capable of storing the plurality of differential rotation angles, and

wherein each of the plurality of differential rotation angles occurs in unit of time, across the recording time.

7. The apparatus for recording rotation angles of a vehicle according to claim 4, further comprising an airbag deployment sensor for detecting whether or not an airbag of the vehicle has been deployed, wherein replacement of the plurality of differential rotation angles recorded in the recording device is disabled when the airbag deployment sensor detects an airbag deployment.

8. The apparatus for recording rotation angles of a vehicle according to claim 4, wherein a recordable area of the recording device gradually increases along a time axis in an amount equivalent to a maximum or minimum differential rotation angle in unit of time, the maximum or minimum differential rotation angle in unit of time being determined based on a maximum or minimum angular velocity that can be output by the angular velocity sensor.

10. The apparatus for recording rotational angles of a vehicle according to claim 4, wherein the plurality of differential rotation angles include the differential rotation angle.