Vehicle rollover detection method and apparatus

• US 20040254710A1
• Filed: 05/06/2004
• Published: 12/16/2004
• Est. Priority Date: 06/12/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Yano, Ryuji
• Granted Patent: US 7,493,204 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60R 2021/01322 comprising variable thresholds, e.g. depending from other collision parameters
• CPC Class Codes: B60R 2021/01327 Angular velocity or angular acceleration
• CPC Class Codes: B60R 21/0132 responsive to vehicle motion parameters , e.g. to vehicle longitudinal or transversal deceleration or speed value

Abstract

There is provided a method for detecting the possibility of rollover of a vehicle, including the steps of: detecting an actual roll angular velocity of the vehicle; obtaining an actual roll angle of the vehicle; determining an actual lateral acceleration of the vehicle; providing a two-dimensional map correlating values of the roll angular velocity with values of the roll angle to define a rollover judgment threshold; changing the threshold based on the actual roll angle and the actual lateral acceleration; forming a plot of the actual roll angular velocity versus the actual roll angle on the two-dimensional map; and judging that there is a possibility that the vehicle rolls over when the plot exceeds the threshold.

Claims

1. A method for detecting the possibility of rollover of a vehicle, comprising:

detecting an actual roll angular velocity of the vehicle;

obtaining an actual roll angle of the vehicle;

determining an actual lateral acceleration of the vehicle;

providing a two-dimensional map correlating values of the roll angular velocity with values of the roll angle to define a rollover judgment threshold;

changing the threshold based on the actual roll angle and the actual lateral acceleration;

forming a plot of the actual roll angular velocity versus the actual roll angle on the two-dimensional map; and

judging that there is a possibility that the vehicle rolls over when the plot exceeds the threshold.

2. A method according to claim 1, wherein said changing includes:

bringing the threshold closer to an origin of the two-dimensional map when the actual roll angle is larger than a reference roll angle under a condition that the actual lateral acceleration is at a given level; and

bringing the threshold farther from the origin of the two-dimensional map when the actual roll angle is smaller than the reference roll angle under a condition that the actual lateral acceleration is at the given level.

3. A method according to claim 2, wherein the threshold is defined by two threshold lines in first and third quadrants of the two-dimensional map and is changed in such a manner that both of the threshold lines are brought closer to or farther from the origin of the two-dimensional map.

4. A method according to claim 1, wherein said determining includes:

detecting a traveling speed of the vehicle;

detecting a steering angle of the vehicle; and

calculating the lateral acceleration from the vehicle traveling speed and steering angle.

5. An apparatus for detecting the possibility of rollover of a vehicle, comprising:

means for detecting an actual roll angular velocity of the vehicle;

means for obtaining an actual roll angle of the vehicle;

means for determining an actual lateral acceleration of the vehicle;

means for providing a two-dimensional map correlating values of the roll angular velocity with values of the roll angle to define a rollover judgment threshold;

means for changing the threshold based on the actual roll angle and the actual lateral acceleration;

means for forming a plot of the actual roll angular velocity versus the actual roll angle on the two-dimensional map; and

means for judging that there is a possibility that the vehicle rolls over when the plot exceeds the threshold.

6. An apparatus according to claim 5, wherein said changing means brings the threshold closer to an origin of the two-dimensional map when the actual roll angle is larger than a reference roll angle under a condition that the lateral acceleration is at a given level, and brings the threshold farther from the origin of the two-dimensional map when the actual roll angle is smaller than the reference roll angle under a condition that the lateral acceleration is at the given level.

7. An apparatus according to claim 5, further comprising:

means for detecting a traveling speed of the vehicle; and

means for detecting a steering angle of the vehicle,

wherein said determining means determines the lateral acceleration from the vehicle traveling speed and steering angle.

8. An apparatus for detecting the possibility of rollover of a vehicle, comprising:

a rate sensor to detect an actual roll angular velocity of the vehicle; and

a controller connected to the rate sensor to read the actual roll angular velocity and storing therein a roll angular velocity versus roll angle map, the roll angular velocity versus roll angle map having threshold lines in first and third quadrants of the map to define rollover ranges on farther sides of the threshold lines from an origin of the map, the controller being configured to;

calculate an actual roll angle of the vehicle from the actual roll angular velocity;

determine an actual lateral acceleration of the vehicle;

calculate a threshold change factor from the actual roll angle and the actual lateral acceleration;

change the threshold lines with reference to the threshold change factor so as to adjust the rollover ranges;

form a plot of the actual roll angular velocity versus the actual roll angle on the map; and

judge the possibility of rollover of the vehicle when the plot falls within either of the rollover ranges.

9. An apparatus according to claim 8, wherein the controller is configured to bring both of the threshold lines closer to the origin of the map so as to enlarge the rollover ranges when the threshold change factor is larger than a reference value and to bring both of the threshold lines farther from the origin of the map so as to narrow the rollover ranges when the threshold change factor is smaller than the reference value.

10. An apparatus according to claim 8, further comprising:

a vehicle speed sensor to detect a traveling speed of the vehicle; and

a steering angle sensor to detect a steering angle of the vehicle,

wherein the controller is connected to the vehicle speed sensor and the steering angle sensor to read the vehicle traveling speed and the steering angle, respectively, and is configured to calculate the lateral acceleration from the vehicle traveling speed and the steering angle.

11. An apparatus according to claim 8, wherein the threshold change factor is calculated by dividing the actual roll angle by the lateral acceleration.