Road friction estimation system and method
AssigneeThe Goodyear Tire & Rubber Company
InventorKanwar Bharat Singh
Life of this patent
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Abstract
A road friction coefficient estimation system and method uses tire load estimation sensors attached to a vehicle's tires. Tire load and slip angle for each tire are estimated from sensor data. From vehicle CAN bus sensors, vehicle acceleration and yaw rate operational parameters are obtained and a dynamic observer model calculates lateral and longitudinal force estimates on each of the tires. An individual wheel force estimation is calculated on each tire from the lateral and longitudinal force estimates for each tire. From the dynamic slip angle estimation on each tire and the individual wheel force estimation on each of the tires, a model-based friction estimation is made.
Claims19
A road friction coefficient estimation system for calculating a road friction coefficient estimation comprising:
- at least one front tire and at least one rear tire supporting a vehicle, at least one tire having at least one strain sensor mounted to the tire for generating a strain sensor signal;
- a tire load estimator generating a load estimation on the one tire from the strain sensor signal;
- a tire slip angle estimator generating a slip angle estimation for the one tire from the strain sensor signal and the load estimation;
- a plurality of vehicle-based sensors for measuring a plurality of vehicle operational parameters;
- a model-based friction estimator generating an estimated road surface friction coefficient based on the plurality of vehicle operational parameters, the load estimation, and the slip angle estimation.
A road friction coefficient estimation system for calculating a road friction coefficient estimation comprising:
- a vehicle having a plurality of supporting tires;
- a tire load estimator generating a dynamic load estimation on each of the plurality of tires from a strain signal received from at least one tire-based strain sensor mounted to a sidewall of each of the plurality of tires;
- a tire slip angle estimator generating a dynamic slip angle estimation on each of the plurality of tires from the strain signal received from the at least one tire-based strain sensor mounted to each of the plurality of tires;
- a plurality of vehicle sensors measuring vehicle acceleration and yaw rate operational parameters;
- a dynamic observer model for calculating lateral and longitudinal force estimates on each of the plurality of tires;
- a load transfer ratio calculator generating an estimated load transfer ratio from the estimated dynamic load on each of the plurality of tires;
- an individual wheel force estimator calculating an individual wheel force estimation on each of the plurality of tires from the lateral and longitudinal force estimates on each of the plurality of tires;
- and
- a model-based friction estimator calculating a surface friction coefficient estimation based on the dynamic slip angle estimation on each of the plurality of tires, the individual wheel force estimation on each of the plurality of tires, and the dynamic load estimation on each of the plurality of tires.
A method of estimating road friction coefficient comprising:
- equipping each tire in a plurality of tires supporting the vehicle with at least one tire-mounted strain sensor measuring strain within a tire sidewall and generating a strain signal;
- generating a dynamic load estimation on each of the plurality of tires based upon the strain signal;
- generating a dynamic slip angle estimation for each of the plurality of tires from a strain signal transmitted by the at least one tire-mounted strain sensor mounted to each of the plurality of tires;
- measuring vehicle acceleration and yaw rate operational parameters using vehicle-mounted sensors;
- calculating lateral and longitudinal force estimates on each of the plurality of tires using a dynamic observer model;
- calculating an estimated load transfer ratio from the estimated dynamic load on each of the plurality of tires;
- calculating an individual wheel force estimation on each of the plurality of tires from the lateral and longitudinal force estimates on each of the plurality of tires;
- and
- calculating an estimated road surface friction coefficient based on the dynamic slip angle estimation on each of the plurality of tires, the estimated dynamic load on each of the plurality of tires, and the individual wheel force estimation on each of the plurality of tires.
Dependencies are inferred from the claim text.