METHOD AND APPARATUS FOR VEHICLE SWAY DETECTION AND REDUCTION

• US 20130030665A1
• Filed: 07/28/2011
• Published: 01/31/2013
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Advics Company Limited (Aisin Corp.), Advics North America Incorporated (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: ASANO, Kenji, NISHIO, Akitaka, KAJITA, Hisashi
• Granted Patent: US 8,700,282 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/182 Brake pressure, e.g. of fluid or between pad and disc
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 40/10 related to vehicle motion
• CPC Class Codes: B60W 40/114 Yaw movement
• CPC Class Codes: B60Y 2200/147 Trailers, e.g. full trailers or caravans

Abstract

A method and apparatus for controlling a vehicle involves determining if the vehicle is swaying and if the vehicle is swaying, reducing a torque of an engine of the vehicle and/or applying independent braking forces to each wheel of the vehicle. A vehicle for controlling vehicle sway includes an engine, a plurality of wheels, a braking system configured to apply independent braking forces to each wheel, and a controller configured to control the engine and the braking system. The controller is configured to determine a correlation coefficient in accordance with any phase shift occurring between a yaw acceleration signal and a lateral acceleration signal. The correlation coefficient is compared to a threshold value to determine whether the vehicle is swaying. If the vehicle is swaying, the controller causes a torque of the engine to be reduced and/or braking forces to be applied independently to each wheel.

Claims

1. A method of determining whether a vehicle is undergoing sway, comprising:

A. sensing yaw acceleration of a moving vehicle by way of a sensor and providing a yaw acceleration output;

B. sensing lateral acceleration of the moving vehicle with a sensor and providing a lateral acceleration signal;

C. determining whether there is a phase shift of the yaw acceleration signal relative to the lateral acceleration signal;

D. calculating the magnitude of the phase shift determined in step C; and

E. comparing the magnitude of the phase shift with a threshold value.

2. The method according to claim 1 wherein the calculation of step D comprises calculating a correlation coefficient by the formula:

3. The method according to claim 2, wherein step E further comprises determining whether the correlation coefficient is less than the threshold value for at least a predetermined time period.

4. The method according to claim 1 wherein the calculation of step D comprises calculating a correlation coefficient by the formula:

5. The method according to claim 4 wherein step E further comprises determining whether the correlation coefficient is less than the threshold value for at least a predetermined time period.

6. The method according to claim 1 wherein the calculation of step D comprises calculating a correlation coefficient by the formula:

7. The method according to claim 6 wherein step E further comprises determining whether the correlation coefficient is less than the threshold value for at least a predetermined time period.

8. The method according to claim 1 further including, if vehicle sway is determined, the step of applying independent braking forces to each wheel of the vehicle to create a yaw movement of opposite phase to the vehicle sway.

9. The method according to claim 8, further including, if vehicle sway is determined, reducing a torque of the engine.

10. The method according to claim 1 further including, if vehicle sway is determined, reducing a torque of the engine.

11. The method according to claim 1, further comprising:

F. determining whether vehicle speed is greater than a predetermined value;

G. determining whether a number of yaw rate oscillations is greater than a predetermined value;

H. determining whether a number of lateral acceleration oscillations is greater than a predetermined value;

I. determining that vehicle sway is occurring if the predetermined values of steps D and F, respectively, are exceeded.

12. A vehicle, comprising:

an engine;

a plurality of wheels;

a braking system configured to apply independent braking forces to each wheel;

sensors which sense yaw acceleration and lateral acceleration of the vehicle while moving to provide a yaw acceleration signal and a lateral acceleration signal; and

a controller operably connected to the engine and the braking system and configured to;

determine whether there is a phase shift of the yaw acceleration signal relative to the lateral acceleration signal;

calculate the magnitude of a phase shift which is determined;

compare the magnitude of the phase shift with a threshold value to determine whether the vehicle is undergoing sway; and

if the vehicle is undergoing sway, perform at least one of;

reducing a torque of the engine and applying a braking force independently to each wheel.

13. A non-transitory tangible computer readable medium which stores a control program for determining whether vehicle sway exists and effecting a control to reduce the vehicle sway in a vehicle which includes an engine, a plurality of wheels, sensors which sense yaw acceleration and lateral acceleration of the vehicle while moving to provide a yaw acceleration signal and a lateral acceleration signal;

the control program enabling a computer to execute a control comprising;

determining whether there exists a phase shift of the yaw acceleration signal relative to the lateral acceleration signal;

calculating, when a phase shift is determined to exist, a magnitude of the phase shift;

determining if the vehicle is undergoing sway by comparing the magnitude of the phase shift with a threshold value; and

reducing a torque of the engine and/or applying a braking force independently to one or more of the wheels by the brake system when it is determined that the vehicle is undergoing sway.