Intelligent tire-based road friction estimation system and method

• US 9,340,211 B1
• Filed: 12/03/2014
• Issued: 05/17/2016
• Est. Priority Date: 12/03/2014
• Status: Active Grant

• Current Assignee: Goodyear Tire & Rubber Company
• Original Assignee: Goodyear Tire & Rubber Company
• Inventors: Singh, Kanwar Bharat
• Primary Examiner(s): Nguyen, Tan Q
• Application Number:
  US14/558,755
• Publication Number:
  US 20160159365A1
• Time in Patent Office: 531 Days
• Field of Search: 701/32.9, 701/72, 701/73, 701/80, 701/41, 731/46, 731/465
• US Class Current: 1/1
• CPC Class Codes: B60T 2210/12 Friction
• CPC Class Codes: B60T 2270/86 Optimizing braking by using ESP vehicle or tire model
• CPC Class Codes: B60T 8/1725 Using tyre sensors, e.g. Sidewall Torsion sensors [SWT] for tyre pressure and temperature detection B60C23/00
• CPC Class Codes: B60W 2400/00 Indexing codes relating to detected, measured or calculated conditions or factors
• CPC Class Codes: B60W 2520/20 Sideslip angle
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 40/068 Road friction coefficient

Abstract

A road friction estimation system and method includes tire-affixed sensors and on-board vehicle sensors, a model-based tire force estimator operable generating from sensor-input a model-derived tire force estimation, a vehicle observer generating an observer-derived tire force estimation and a friction estimator generating a road friction estimation from a comparison of the model-derived tire force estimation and the observer-derived tire force estimation.

Claims

1. A road friction estimation system for a road on which a vehicle is traversing, comprising:

the vehicle having at least one supportive vehicle tire, the vehicle tire having a tire cavity and a ground-engaging tread, and the tire having a plurality of tire-specific parameters;

a plurality of tire-affixed sensors mounted to the tire operably measuring the tire-specific parameters to generate tire-specific information;

a plurality of on-board vehicle sensors mounted to operably measure a plurality of vehicle-specific parameters to generate vehicle-specific information;

a model-based tire force estimator operable to generate a model-derived tire force estimation;

a vehicle observer operable to generate an observer-derived tire force estimation;

a friction estimator operable to generate a road friction estimation from a comparison of the model-derived tire force estimation and the observer-derived tire force estimation;

wherein the vehicle observer receives a plurality of inputs based upon the tire-specific information; and

wherein the plurality of inputs to the vehicle observer comprises;

a load estimation for the one vehicle tire;

a slip angle estimation for the one vehicle tire;

a cornering stiffness estimation for the one tire.

2. The road friction estimation system of claim 1, wherein the cornering stiffness estimation for the one tire comprises cornering stiffness adaptation inputs based upon the tire-specific information.

3. The road friction estimation system of claim 2, wherein the cornering stiffness adaptation inputs comprise temperature change within the one tire, pressure change within the one tire, wear state of the one tire and loading on the one tire.

4. The road friction estimation system of claim 3, wherein the model-based tire force estimator operably utilizes a slip-dependent friction function.

5. The road friction estimation system of claim 3, wherein the cornering stiffness adaptation input providing the loading on the one tire is derived from a dynamic load estimator having as inputs the vehicle-specific information and the tire-specific information.

6. The road friction estimation system of claim 3, wherein the cornering stiffness adaptation inputs providing the changes in the temperature and the pressure of the one tire are derived from the plurality of tire-affixed sensors.

7. A road friction estimation system for estimating a friction coefficient for a road on which a vehicle is traversing, comprising:

the vehicle having at least one supportive vehicle tire, the vehicle tire having a tire cavity and a ground-engaging tread, and the tire having a plurality of tire-specific parameters;

a plurality of tire-affixed sensors mounted to the tire operably measuring the tire-specific parameters to generate tire-specific information;

a plurality of on-board vehicle sensors mounted to operably measure a plurality of vehicle-specific parameters to generate vehicle-specific information;

a model-based tire force estimator operable to generate a model-derived tire force estimation;

a vehicle observer operable to generate an observer-derived tire force estimation;

a friction estimator operable to generate a road friction estimation from a comparison of the model-derived tire force estimation and the observer-derived tire force estimation;

wherein the vehicle observer receives a plurality of inputs based upon the tire-specific information, the plurality of inputs to the vehicle observer are determined from the tire-affixed sensors and comprise;

a load estimation for the one vehicle tire;

a slip angle estimation for the one vehicle tire;

a cornering stiffness estimation for the one tire.

8. The road friction estimation system of claim 7, wherein the cornering stiffness estimation for the one tire receives a plurality of stiffness adaptation inputs based upon the tire-specific information, the cornering stiffness adaptation inputs comprising:

temperature change within the one tire;

pressure change within the one tire;

wear state of the one tire; and

loading on the one tire.

9. The road friction estimation system of claim 8, wherein the model-based tire force estimator operably utilizes a slip-dependent friction function.

10. A method for estimating road friction on which a vehicle is traversing, comprising:

equipping the vehicle with at least one supportive vehicle tire, the vehicle tire having a tire cavity and a ground-engaging tread, and the tire having a plurality of tire-specific parameters;

attaching a plurality of tire-affixed sensors to the tire operably measuring the tire-specific parameters to generate tire-specific information;

attaching a plurality of on-board vehicle sensors to the vehicle to operably measure a plurality of vehicle-specific parameters to generate vehicle-specific information;

generating from a model-based tire force estimator a model-derived tire force estimation;

generating from a vehicle observer an observer-derived tire force estimation;

generating from a friction estimator a road friction estimation from a comparison of the model-derived tire force estimation and the observer-derived tire force estimation; and

wherein the plurality of inputs to the vehicle observer comprises;

a load estimation for the one vehicle tire;

a slip angle estimation for the one vehicle tire;

a cornering stiffness estimation for the one tire.

11. The method of claim 10, wherein further comprising inputting cornering stiffness adaptation inputs into the cornering stiffness estimation.

12. The method of claim 11, wherein the cornering stiffness adaptation inputs comprise temperature change within the one tire, pressure change within the one tire, wear state of the one tire and loading on the one tire.

13. The method of claim 12, wherein further comprising deriving the cornering stiffness adaptation input from a dynamic load estimator having as inputs the vehicle-specific information and the tire-specific information.

14. The method of claim 13, wherein further comprising determining the changes in the temperature and the pressure of the one tire from the plurality of tire-affixed sensors.