Judgment Line Calculations for a Vehicle Safety System

• US 20090322500A1
• Filed: 06/25/2008
• Published: 12/31/2009
• Est. Priority Date: 06/25/2008
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Williams, Paul R., Chatterjee, Aamrapali
• Granted Patent: US 7,916,006 B2
• Time in Patent Office: Days
• US Class Current: 340/435
• CPC Class Codes: B60T 2201/022 Collision avoidance systems
• CPC Class Codes: B60T 2260/02 Active Steering, Steer-by-Wire
• CPC Class Codes: B60T 8/17558 specially adapted for collision avoidance or collision mitigation road vehicle drive control systems for collision avoidance otherwise than by controlling a particular sub-unit B60W30/09
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2554/4041 Position
• CPC Class Codes: B60W 2554/4042 Longitudinal speed
• CPC Class Codes: B60W 2554/804 Relative longitudinal speed
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B62D 15/029 Steering assistants using warnings or proposing actions to the driver without influencing the steering system

Abstract

A vehicle has a safety system including at least one object sensor to detect a distance from an object in a path of the vehicle and the speed and acceleration of the object. The sensor data is input into a control to determine a desired braking judgment line and a steering judgment line between the vehicle and the object. The safety system then compares the vehicle and object acceleration. Following, the safety system calculates a judgment line between the object and the vehicle based upon equations for the determined scenario. The judgment line is then used to determine a warning distance and warn a vehicle operator.

Claims

1. A safety system for a vehicle comprising:

at least one object sensor configured to detect a distance from an object in a path of the vehicle and the speed and acceleration of the object;

at least one vehicle sensor configured to determine a speed and acceleration of the vehicle; and

a control to determine a first amount of time until the vehicle must begin braking to avoid contact with the object and a second amount of time until the vehicle must begin steering to avoid contact with the object, with the first and second amount of times being based on the detected distance, the speed and acceleration of the object and the speed and acceleration of the vehicle.

2. The safety system of claim 1, wherein the at least one vehicle sensor is a speedometer.

3. The safety system of claim 1, wherein the first amount of time and the second amount of time are based upon a predetermined distance between the vehicle and the object when the braking and the steering are complete.

4. The safety system of claim 1, wherein the first amount of time and the second amount of time are each based on the vehicle speed and acceleration and the object speed and acceleration.

5. A method for determining a warning for a vehicle safety system comprising:

initiating the safety system with at least one input;

comparing a vehicle acceleration and an object acceleration and selecting from a set of predetermined equations based upon the compared accelerations;

calculating an amount of time to perform at least one of braking and steering to avoid contact with the object using the selected predetermined equations;

determining a distance between the vehicle and the object at which a warning must be conveyed to the vehicle operator, at least partially based upon the calculated amount of time; and

warning a vehicle operator to perform the one of braking and steering based upon the determined distance.

6. The method of claim 5, wherein the initiating the safety system further comprises detecting an object with a sensor.

7. The method of claim 5, wherein the calculating an amount of time further comprises calculating an amount of time to brake and an amount of time to contact with the object.

8. The method of claim 5, wherein the calculating an amount of time further comprises calculating an amount of time to steer and an amount of time to contact with the object.

9. The method of claim 5, wherein the set of predetermined equations include equations based on:

the vehicle velocity being constant and the object velocity being constant;

the vehicle velocity being constant and the object velocity being not constant;

the vehicle velocity being not constant and the object velocity being constant; and

the vehicle velocity being not constant and the object velocity being not constant.

10. A method for determining a warning for a vehicle safety system comprising:

initiating the safety system with at least one input;

comparing a vehicle acceleration and an object acceleration and selecting from a set of predetermined equations for an applicable safety system scenario based upon the compared accelerations;

calculating a first amount of time until contact between the object and the vehicle based upon equations for the determined applicable safety system scenario;

calculating a second amount of time until contact between the object and the vehicle based upon equations for the determined applicable safety system scenario;

determining a warning distance based upon the calculated first and second amounts of time; and

warning a vehicle operator based upon the determined warning distance.

11. The method of claim 10, wherein the initiating the safety system further comprises detecting an object in a vehicle path with a sensor.

12. The method of claim 10, wherein the calculating the first amount of time further comprises calculating a time to brake and a time to contact.

13. The method of claim 10, wherein the calculating the second amount of time further comprises calculating a time to steer and a time to contact.

14. The method of claim 10, wherein the determining the warning distance further comprises:

calculating a braking warning distance;

calculating a steering warning distance; and

comparing the braking warning distance to the steering warning distance to determine a desired warning distance.

15. The method of claim 14, wherein the desired warning distance is the farther distance of the braking warning distance and the steering warning distance.

16. The method of claim 10, wherein the determined applicable safety system scenario is based on one of:

the vehicle velocity being constant and the object velocity being constant;

the vehicle velocity being constant and the object velocity being not constant;

the vehicle velocity being not constant and the object velocity being constant; and

the vehicle velocity being not constant and the object velocity being not constant.