VEHICLE STABILITY CONTROL SYSTEM AND METHOD

• US 20140012477A1
• Filed: 08/28/2013
• Published: 01/09/2014
• Est. Priority Date: 01/23/2008
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: LU, Jianbo, JOHNSON, Leonard K., MEYERS, Joseph Carr
• Granted Patent: US 9,352,731 B2
• Time in Patent Office: Days
• US Class Current: 701/78
• CPC Class Codes: B60K 31/00 Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator fittings acting on two or more sub-units B60W30/14; speedometers G01P; systems or devices for controlling speed in general G05D13/00 ; in traffic anti-collision system for road vehicles G08G1/16
• CPC Class Codes: B60T 2201/04 Hill descent control
• CPC Class Codes: B60T 2201/06 Hill holder; Start aid systems on inclined road
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60T 7/122 for locking of reverse movement
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/17551 determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters
• CPC Class Codes: B60T 8/17552 responsive to the tire sideslip angle or the vehicle body slip angle
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2510/0225 Clutch actuator position
• CPC Class Codes: B60W 2510/0604 Throttle position
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2510/186 Status of parking brakes
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/12 : Brake pedal position
• CPC Class Codes: B60W 2552/15 : Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/0677 : Engine power
• CPC Class Codes: B60W 30/18118 : Hill holding

Abstract

A vehicle stability control system comprises a 5-sensor cluster and a stability controller configured to communicate with the 5-sensor cluster and receive signals corresponding to a lateral acceleration, a longitudinal acceleration, a yaw rate, a roll rate, and a pitch rate from the 5-sensor cluster. The stability controller can also be configured to determine a braking amount or a throttle amount to maintain vehicle stability. The system also comprises a brake controller configured to communicate with the stability controller and receive a braking request from the stability controller, and a throttle controller configured to communicate with the stability controller and receive a throttle request from the stability controller. The system may also comprise a braking or throttling command computed based on various scenarios detected by measured and calculated signals.

Claims

1. A vehicle stability control system, comprising:

a 5-sensor cluster;

a stability controller configured to communicate with the 5-sensor cluster and receive signals corresponding to a lateral acceleration, a longitudinal acceleration, a yaw rate, a roll rate, and a pitch rate from the 5-sensor cluster, the stability controller also configured to determine a braking amount or a throttle amount to maintain vehicle stability;

a brake controller configured to communicate with the stability controller and receive a braking request from the stability controller; and

a throttle controller configured to communicate with the stability controller and receive a throttle request from the stability controller.

2. The vehicle stability control system of claim 1, wherein the stability controller is configured to receive signals corresponding to a sideslip angle, a vehicle longitudinal velocity, wheel speeds, a throttle input, a transmission status, and a brake status.

3. The vehicle stability control system of claim 2, wherein the stability controller is configured to receive signals corresponding to a clutch status.

4. The vehicle stability control system of claim 2, wherein the brake status includes a foot brake stratus and a parking brake status.

5. The vehicle stability control system of claim 1, wherein the stability controller comprises a state estimator.

6. The vehicle stability control system of claim 1, wherein the state estimator is configured to receive signals corresponding to the lateral acceleration, the longitudinal acceleration, the yaw rate, the roll rate, and the pitch rate from the 5-sensor cluster.

7. The vehicle stability control system of claim 6, wherein the state estimator is configured to determine road grade based on inputs from the 5-sensor cluster.

8. The vehicle stability control system of claim 7, wherein the state estimator is configured to use the road grade to determine whether the vehicle'"'"'s throttle or brakes should be activated via a throttle request or braking request, respectively.

21. The vehicle stability control system of claim 1, wherein the stability controller is configured to detect a vehicle sliding into a loss of control.

9. A method for performing hill hold control, the method comprising:

receiving signals corresponding to a lateral acceleration, a longitudinal acceleration, a yaw rate, a roll rate, and a pitch rate;

calculating a vehicle pitch angle from the lateral acceleration, the longitudinal acceleration, the yaw rate, the roll rate, and the pitch rate;

calculating a road grade from the vehicle pitch angle; and

determining whether to apply brakes of a vehicle based on the road grade, a vehicle speed or wheel speeds, a transmission status, a throttle input, and a brake status.

10. The method of claim 9, wherein determining whether to apply brakes of the vehicle is based additionally on a sideslip angle.

11. The method of claim 9, wherein determining whether to apply brakes of the vehicle is based additionally on a clutch status.

12. The method of claim 9, further including applying brakes of the vehicle when appropriate until driver applies brakes or presses throttle when in gear.

13. The method of claim 9, wherein the lateral acceleration, the longitudinal acceleration, the yaw rate, the roll rate, and the pitch rate are received from a 5-sensor cluster.

14-20. -20. (canceled)

22. A method for detecting a vehicle sliding into loss of control, the method comprising:

receiving signals corresponding to a lateral acceleration, a longitudinal acceleration, a yaw rate, a roll rate, and a pitch rate;

calculating a vehicle pitch angle from the lateral acceleration, the longitudinal acceleration, the yaw rate, the roll rate, and the pitch rate;

calculating a longitudinal velocity gradient from the vehicle pitch angle;

calculating a signed longitudinal velocity based on the longitudinal velocity gradient;

calculating a sideslip angle;

comparing the magnitude of the sideslip angle with a first threshold indicative of the vehicle'"'"'s motion trend; and

comparing the magnitude of the longitudinal velocity gradient with a second threshold indicative of lateral motion of the vehicle.

23. A vehicle stability control system for controlling a vehicle'"'"'s sliding into loss of control, the system comprising:

detecting the vehicle'"'"'s sliding into loss of control by comparing the vehicle'"'"'s longitudinal velocity gradient with a reference speed computed from wheel speed sensors inputs;

detecting a lateral velocity of the vehicle and a longitudinal velocity of the vehicle when vehicle sliding is detected;

calculating a sliding velocity vector of the vehicle from the lateral velocity of the vehicle and the longitudinal velocity of the vehicle;

braking the vehicle such that tire forces of the vehicle are aligned in a direction opposite the vehicle sliding velocity vector to remove a sliding energy of the vehicle.

26. The method of claim 23, wherein braking the vehicle comprises braking until input is received from a driver to apply brakes or press a throttle of the vehicle when the vehicle is in gear.

27. The method of claim 23, wherein braking the vehicle comprises applying an amount of brake pressure proportional to at least one of the reference speed computed from the wheel speed sensors inputs and the longitudinal velocity gradient.

24. A method for performing hill hold control for a vehicle, the method comprising:

receiving signals corresponding to a lateral acceleration, a longitudinal acceleration, a yaw rate, a roll rate, and a pitch rate;

calculating a sideslip angle based on at least the lateral acceleration;

calculating a vehicle pitch angle from the lateral acceleration, the longitudinal acceleration, the yaw rate, the roll rate, and the pitch rate;

calculating a longitudinal velocity gradient from the longitudinal acceleration, yaw rate, the sideslip angle, and a global pitch angle;

calculating a road grade from the vehicle pitch angle and the global pitch angle;

detecting back sliding using the road grade, a vehicle speed or wheel speeds, a vehicle side slip angle, and the longitudinal velocity gradient; and

applying braking when back sliding is detected.

25. A method for performing hill hold control for a vehicle, the method comprising:

receiving signals corresponding to a lateral acceleration, a longitudinal acceleration, a yaw rate, a roll rate, a pitch rate, and wheel speed;

calculating a sideslip angle based on at least the lateral acceleration;

calculating a vehicle pitch angle from the lateral acceleration, the longitudinal acceleration, the yaw rate, the roll rate, and the pitch rate;

calculating a road grade from the vehicle pitch angle and a global pitch angle, and when an inclined or decline road grade is calculated;

calculating a longitudinal velocity gradient from the longitudinal acceleration, yaw rate, the sideslip angle, and the global pitch angle;

detecting back sliding using the road grade, a vehicle speed or wheel speeds, the side slip angle, and the longitudinal velocity gradient;

detecting undesired acceleration of the vehicle using wheel speed; and

applying braking when one or more of back sliding and undesired acceleration is detected, and maintain braking until a driver of the vehicle applies a sufficient level of braking or throttle.