Method and system for vehicle ESC system using map data

• US 20110251749A1
• Filed: 04/09/2010
• Published: 10/13/2011
• Est. Priority Date: 04/09/2010
• Status: Active Grant

• Current Assignee: HERE Global B.V. (Nokia Corporation), University of Iowa Research Foundation
• Original Assignee: HERE Global B.V. (Nokia Corporation)
• Inventors: Schwarz, Chris, Moran, Kevin, Denaro, Robert
• Granted Patent: US 8,437,936 B2
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60T 2210/22 Banked curves
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• 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 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: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/188 hydraulic brakes
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2552/05 Type of road, e.g. motorways, local streets, paved or unpaved roads
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2552/25 Road altitude
• CPC Class Codes: B60W 2552/30 Road curve radius
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 2710/0605 Throttle position
• CPC Class Codes: B60W 2720/14 Yaw
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability

Abstract

An Electronic Stability Control (ESC) system for a vehicle is disclosed. An electronic control unit (ECU) is programmed to reduce vehicle lateral skidding by reducing differences between an intended vehicle yaw rate and an actual vehicle yaw rate by applying modifications to operation of the vehicle brakes and/or throttle. The ESC system receives inputs from wheel speed sensors, a steering wheel position sensor, a yaw rate sensor and a lateral acceleration sensor. The ECS system also receives input that indicates at least a property of the road upon which the vehicle is located, wherein the road upon which the vehicle is located is determined from a positioning system that uses a map database and the property is determined from the map database. The ESC system incorporates the road property information in determining when and/or how to modify operation of the vehicle to reduce vehicle skidding.

Claims

1. An improved Electronic Stability Control system for a vehicle comprising:

a map database that includes data that indicates properties of roads in a road network including shapes of roads upon which the vehicle travels;

a positioning system operably coupled to the map database to determine a position of the vehicle on a road in the road network;

an electronic control unit comprising a processor operable to execute programming functions, wherein said electronic control unit is operably coupled to sensors that indicate a vehicle yaw rate and a steering wheel position, and further wherein said electronic control unit is operably coupled to the positioning system to receive information indicating the position of the vehicle on the road, and wherein said electronic control unit includes outputs to brake actuators associated with brakes associated with individual wheels of said vehicle; and

a ESC program run on the electronic control unit that uses inputs from the sensors and information from the map database that indicates a shape of the road upon which the vehicle is located to determine sensitivity to differences between an intended vehicle yaw rate and an actual vehicle yaw rate to determine whether to provide outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

2. The system of claim 1 wherein the ESC program uses the information from the map database that indicates the shape of a portion of the road ahead of where the vehicle is located out to an extent to determine whether to provide outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

3. The system of claim 1 wherein the ESC program uses the information from the map database that indicates the shape of the road where the vehicle is located to determine whether to provide an output to a throttle actuator associated with a vehicle throttle to reduce vehicle speed.

4. The system of claim 1 wherein the ESC program also uses information from the map database that indicates road slope to determine whether to provide outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

5. The system of claim 1 wherein the ESC program also uses information from the map database that indicates road width to determine whether to provide outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

6. The system of claim 1 wherein the ESC program also uses information from the map database that indicates road bank angle to determine whether to provide outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

7. The system of claim 1 wherein the ESC program uses the information from the map database that indicates the shape of the portion of the road ahead of where the vehicle is located out to an extent to determine whether to provide an output to a throttle actuator associated with a vehicle throttle to reduce a speed of the vehicle.

8. The system of claim 1 wherein the ESC program also uses the information from the map database that indicates the shape of the road upon which the vehicle is located to determine a recovery action, wherein the recovery action is implemented by providing outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

9. The system of claim 1 wherein the ESC program also uses the information from the map database that indicates the shape of a portion of the road ahead of where the vehicle is located out to an extent to determine a recovery action, wherein the recovery action is implemented by providing outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

10. The system of claim 9 wherein the recovery action also includes providing outputs to a throttle actuator associated with a vehicle throttle to modify vehicle speed.

11. A method of operation for an electronic stability control system in a vehicle, the method comprising the steps of:

determining a location of the vehicle along a road in a road network;

accessing a map database to determine a shape of the road at the location of the vehicle along the road;

obtaining outputs from sensors in the vehicle that indicate an actual vehicle yaw rate and an intended vehicle yaw rate;

upon determining that the actual vehicle yaw rate exceeds the intended vehicle yaw rate by a threshold value, wherein the threshold value is determined at least in part by the shape of the road at the location of the vehicle along the road, providing outputs to brake actuators to reduce a difference between the actual vehicle yaw rate and the intended vehicle yaw rate.

12. The method of claim 11 further comprising the steps of:

determining a portion of the road network onto which the vehicle could travel from the location; and

accessing the map database to determine shapes of roads in the portion of the road network onto which the vehicle could travel from the location;

and further wherein the threshold value is determined at least in part by the shapes of roads in the portion of the road network onto which the vehicle could travel from the location.

13. The method of claim 11 further comprising:

upon determining that the actual vehicle yaw rate exceeds the intended vehicle yaw rate by the threshold value, providing an output to a throttle actuator associated with a vehicle throttle to reduce vehicle speed.

14. The method of claim 11 further comprising:

accessing the map database to determine road slope at the location of the vehicle along the road;

and further wherein the threshold value is determined at least in part by the road slope at the location of the vehicle along the road.

15. The method of claim 11 further comprising:

accessing the map database to determine road width at the location of the vehicle along the road;

and further wherein the threshold value is determined at least in part by the road width at the location of the vehicle along the road.

16. The method of claim 11 further comprising:

accessing the map database to determine road bank angle at the location of the vehicle along the road;

and further wherein the threshold value is determined at least in part by the road bank angle at the location of the vehicle along the road.

17. The method of claim 11 further comprising the steps of:

determining a portion of the road network onto which the vehicle could travel from the location;

accessing the map database to determine shapes of roads in the portion of the road network onto which the vehicle could travel from the location, wherein the threshold value is determined at least in part by the shapes of roads in the portion of the road network onto which the vehicle could travel from the location; and

providing an output to a throttle actuator associated with a vehicle throttle to reduce vehicle speed upon determining that the actual vehicle yaw rate exceeds the intended vehicle yaw rate by the threshold value.

18. The method of claim 11 further comprising:

using the information from the map database that indicates the shape of the road upon which the vehicle is located to determine a recovery action; and

implementing the recovery action by providing outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

19. The method of claim 11 further comprising:

using the information from the map database that indicates the shape of a portion of the road ahead of where the vehicle is located out to an extent to determine a recovery action; and

implementing the recovery action by providing outputs to the brake actuators to reduce differences between the intended vehicle yaw rate and the actual vehicle yaw rate.

20. The method of claim 19 further comprising:

providing output to a throttle actuator associated with a vehicle throttle to modify vehicle speed.