Lateral and longitudinal velocity determination for an automotive vehicle

• US 7,451,033 B2
• Filed: 06/10/2005
• Issued: 11/11/2008
• Est. Priority Date: 06/10/2005
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Tseng, Hongtei Eric, Meyers, Joseph C., Xu, Li
• Primary Examiner(s): Beaulieu; Yonel
• Application Number:
  US11/160,148
• Publication Number:
  US 20070005212A1
• Time in Patent Office: 1,250 Days
• Field of Search: 701/70, 701 45- 47, 701/36, 340/425.5, 340/438, 280734-735, 280/728.1, 180/170, 307/9.1
• US Class Current: 701/70
• 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
• CPC Class Codes: B60T 2250/04 Vehicle reference speed; Vehicle body speed
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 30/045 Improving turning performance
• CPC Class Codes: B60W 40/10 related to vehicle motion

Abstract

A system (18) for controlling a safety system (44) of a vehicle (10) is disclosed herein. The system includes a longitudinal acceleration sensor (36), a vehicle or wheel speed sensor(s) (20), a lateral acceleration sensor (32), a yaw rate sensor (28), and a controller (26). The controller determines a stability index and provides a first observer that determines a reference longitudinal velocity in response to the sensors. The controller determines a reference lateral velocity in response to the sensors. The controller provides a second observer that determines a second longitudinal velocity in response to the sensors and a first adjustment based on the reference longitudinal velocity. The controller determines a second lateral velocity in response to the sensors and a second adjustment based on the reference lateral velocity. The controller determines an output lateral velocity and an output longitudinal velocity in response to the first and second observers and the stability index and accordingly controls the safety system.

Claims

1. A system for controlling a safety system of an automotive vehicle, said system comprising:

a plurality of wheel speed sensors;

a longitudinal acceleration sensor for generating a longitudinal acceleration signal;

a vehicle speed sensor for generating a vehicle speed signal;

a lateral acceleration sensor for generating a lateral acceleration signal;

a yaw rate sensor for generating a yaw rate signal; and

a controller coupled to said longitudinal acceleration sensor, said vehicle speed sensor, said lateral acceleration sensor, and said yaw rate sensor;

wherein said controller is operable to determine a stability index and provide a first observer for determining a reference longitudinal velocity in response to said longitudinal acceleration signal, said yaw rate signal, a pitch attitude, and vehicle speed from said wheel speed sensors;

wherein said controller is operable to determine a reference lateral velocity in response to said lateral acceleration signal, said yaw rate signal, a roll attitude, a pitch attitude, and vehicle speed from said wheel speed sensors;

wherein said controller is operable to provide a second observer for determining a second longitudinal velocity in response to said longitudinal acceleration signal, said yaw rate signal, a lateral velocity, said pitch attitude, and a first adjustment based on said reference longitudinal velocity;

wherein said controller is operable to determine a second lateral velocity in response to said lateral acceleration signal, said yaw rate signal, a roll attitude, a pitch attitude, and a second adjustment based on said reference lateral velocity;

wherein said controller is operable to determine an output lateral velocity and an output longitudinal velocity in response to said first observer, said second observer, and said stability index; and

wherein said controller is operable to control said safety system in response to said output lateral velocity and said output longitudinal velocity.

2. A system as recited in claim 1, wherein said safety system includes at least one system selected from the group consisting of an antilock-brake system (ABS), a roll stability control (RSC) system, a traction control system, and a yaw stability control (YSC) system.

3. A system as recited in claim 1, wherein said controller is operable to determine said output lateral velocity and said output longitudinal velocity in response to said first observer, said second observer, said stability index, and the wheel speed from at least one of said wheel speed sensors.

4. A method for controlling a system of a vehicle, said method comprising the steps of:

determining a stability index;

providing a first observer that determines a reference longitudinal velocity in response to a longitudinal acceleration, yaw rate, a pitch attitude, and vehicle speed from wheel speed sensors;

determining a reference lateral velocity in response to a lateral acceleration, yaw rate, a roll attitude, a pitch attitude, and vehicle speed from wheel speed sensors;

providing a second observer that determines a second longitudinal velocity in response to a longitudinal acceleration, yaw rate, a lateral velocity, a pitch attitude, and a first adjustment based on said reference longitudinal velocity;

determining a second lateral velocity in response to a lateral acceleration, yaw rate, said roll attitude, said pitch attitude, and a second adjustment based on said reference lateral velocity;

determining an output lateral velocity and an output longitudinal velocity in response to said first observer, said second observer, and said stability index; and

controlling a vehicle system in response to said output lateral velocity and said output longitudinal velocity.

5. A method as recited in claim 4, wherein said output lateral velocity and said output longitudinal velocity are determined in response to said first observer, said second observer, said stability index, and the wheel speed from at least one of said wheel speed sensors.

6. A method as recited in claim 4, wherein said output lateral velocity and said output longitudinal velocity are determined in response to said first observer when said yaw rate is above said stability index.

7. A method as recited in claim 4, wherein said output lateral velocity and said output longitudinal velocity are determined in response to said first observer when said yaw rate is above said stability index and the wheel speed from at least one of said wheel speed sensors is reliable.

8. A method as recited in claim 4, wherein said output lateral velocity and said output longitudinal velocity are determined in response to said second observer when said yaw rate is below said stability index or the wheel speed from at least one of said wheel speed sensors is unreliable.

9. A method as recited in claim 8, wherein said wheel speed is unreliable during antilock braking.

10. A method as recited in claim 4, said method further comprising the step of resetting said reference lateral velocity and said second lateral velocity in response to a linear slip angle of a rear axle.

11. A method as recited in claim 4, said method further comprising the step of resetting said reference lateral velocity and said second lateral velocity in response to a linear slip angle of a rear axle and about zero.

12. A method as recited in claim 4, wherein said second observer is a kinematic-based observer.

13. A method for controlling a system of a vehicle, said method comprising the steps of:

generating a plurality of wheel speed signals with a plurality of wheel speed sensors;

determining vehicle speed in response to said plurality of wheel speed signals;

generating a lateral acceleration signal;

generating a yaw rate signal;

generating a longitudinal acceleration signal;

determining a stability index in response to said yaw rate signal;

determining a reference longitudinal velocity in response to said longitudinal acceleration signal, said yaw rate signal, a pitch attitude, and said vehicle speed;

determining a second longitudinal velocity in response to said longitudinal acceleration signal, said yaw rate signal, a lateral velocity, and a pitch attitude;

determining an output longitudinal velocity from either said reference longitudinal velocity or said second longitudinal velocity in response to said stability index; and

controlling a vehicle system in response to said output longitudinal velocity.

14. A method as recited in claim 13, wherein said output longitudinal velocity is determined in response to a first observer, a second observer, said stability index, and the wheel speed from at least one of said wheel speed sensors.

15. A method as recited in claim 13, wherein said output longitudinal velocity is determined in response to a first observer when the yaw rate is above said stability index.

16. A method as recited in claim 13, wherein said output longitudinal velocity is determined in response to a first observer when the yaw rate is above said stability index and the wheel speed from at least one of said wheel speed sensors is reliable.

17. A method as recited in claim 16, wherein said output longitudinal velocity is determined in response to a second observer when said yaw rate is below said stability index or the wheel speed from at least one of said wheel speed sensors is unreliable.

18. A method for controlling a system of a vehicle, said method comprising the steps of:

generating a plurality of wheel speed signals with a plurality of wheel speed sensors;

determining vehicle speed in response to said plurality of wheel speed signals;

generating a lateral acceleration signal;

generating a longitudinal acceleration signal;

generating a yaw rate signal;

determining a stability index in response to said yaw rate signal;

determining a reference lateral velocity in response to said lateral acceleration signal, said yaw rate signal, a roll attitude, a pitch attitude, and said vehicle speed;

determining a second lateral velocity in response to said lateral acceleration signal, said yaw rate signal, said roll attitude, said pitch attitude, and a second adjustment based on said reference lateral velocity;

determining an output lateral velocity from either said reference lateral velocity or said second lateral velocity in response to said stability index; and

controlling a vehicle system in response to said output lateral velocity.

19. A method as recited in claim 18, said method further comprising the step of resetting said reference lateral velocity and said second lateral velocity in response to a linear slip angle of a rear axle and about zero.

20. A method as recited in claim 18, wherein said output lateral velocity is determined in response to a first observer when the yaw rate is above said stability index.

21. A method as recited in claim 18, wherein said output lateral velocity is determined in response to a first observer when the yaw rate is above said stability index and the wheel speed from at least one of said wheel speed sensors is reliable.

22. A method as recited in claim 21, wherein said output lateral velocity is determined in response to a second observer when said yaw rate is below said stability index or the wheel speed from at least one of said wheel speed sensors is unreliable.