Tire wear state estimation system utilizing cornering stiffness and method

Abstract

A tire wear state estimation system includes as inputs an axle force estimation, a measured tire inflation pressure; a tire load estimation; a tire cornering stiffness estimation; and a tire identification by which a specific tire-based correlation model correlates tire inflation pressure, the tire load estimation, the tire cornering stiffness estimation, and the vehicle-based sensor axle force estimation.

What is claimed is: 
     
         1 . A tire wear state estimation system comprising:
 at least one tire supporting a vehicle;   tire pressure measuring means affixed to the one tire for measuring tire inflation pressure;   tire load measuring means for measuring tire load;   tire cornering stiffness measuring means for measuring tire cornering stiffness;   tire identification means for identifying the tire; and   tire wear estimation means for calculating an estimation of a tire wear state based upon inputs comprising the tire inflation pressure, the tire load, the tire cornering stiffness, and the tire identification.   
     
     
         2 . The tire wear state estimation system of  claim 1 , wherein the tire pressure measuring means comprises a tire-mounted pressure measuring device operative to measure by a pressure sensor a tire cavity pressure and transmit tire inflation pressure data from the tire cavity pressure measurement. 
     
     
         3 . The tire wear state estimation system of  claim 2 , wherein tire identification data is stored within and accessible from the tire-mounted pressure measuring device. 
     
     
         4 . The tire wear state estimation system of  claim 2 , wherein the tire cornering stiffness measuring means comprises:
 at least one on-board vehicle based sensor;   a cornering stiffness estimator model operatively using vehicle information input from the at least one on-board vehicle based sensor.   
     
     
         5 . The tire wear state estimation system of  claim 4 , wherein the cornering stiffness estimator model comprises:
 an axle force estimator receiving the vehicle information input and operative to generate an axial force component estimation;   a tire slipangle estimator for generating a tire slipangle estimation based on the vehicle information input and the vehicle sideslip angle estimation; and   an axle cornering stiffness estimator for generating an axle cornering stiffness estimation based on the tire slip angle estimation and the axial force component estimation.   
     
     
         6 . The tire wear state estimation system of  claim 5 , wherein the axle cornering stiffness estimator comprises a recursive least squares algorithm with forgetting factor based on a polynomial model capturing a dependency between axle force component estimation and the tire slip angle estimation. 
     
     
         7 . The tire wear state estimation system of  claim 5 , further comprising a vehicle sideslip angle estimator operative to generate a vehicle sideslip angle estimation from the axial force component estimation, the tire slip angle estimator generating the tire slip angle estimation based on the vehicle slip angle estimation and the axial force component estimation. 
     
     
         8 . The tire wear state estimation system of  claim 5 , wherein the tire slip angle estimator comprises a sliding mode observer for non-linear systems. 
     
     
         9 . The tire wear state estimation system of  claim 1 , wherein the tire wear estimation means comprises a correlation model based on the tire identification between the tire wear state, the tire inflation, the tire load, and the tire cornering stiffness. 
     
     
         10 . The tire wear state estimation system of  claim 8 , wherein the correlation model comprises a recursive least squares algorithm based on a polynomial model with forgetting factor capturing a dependency between the tire wear state, the tire inflation, and the tire cornering stiffness for a tire-specific tire identification. 
     
     
         11 . A tire wear state estimation system comprising:
 at least one tire for supporting a vehicle;   a tire-mounted pressure measuring device affixed to the one tire operative to measure a tire pressure within a tire cavity;   tire identification stored within and accessible from a tire-mounted data storage device;   tire load measuring means for measuring tire load;   tire cornering stiffness measuring means for measuring tire cornering stiffness; and   tire wear estimation means for calculating an estimation of a tire wear state based upon inputs comprising the tire inflation, the tire load, the tire cornering stiffness, and the tire identification.   
     
     
         12 . The tire wear state estimation system of  claim 11 , wherein the tire cornering stiffness measuring means comprises a cornering stiffness estimator model operatively using vehicle information input from at least one on-board vehicle based sensor generating vehicle operational information; and the cornering stiffness estimator model comprises an axle force estimator receiving the vehicle operational information and operative to generate an axial force component estimation based on the vehicle operational information. 
     
     
         13 . The tire wear estimation system of  claim 11 , wherein further comprising:
 a vehicle side slip angle estimator for generating a vehicle side slip angle estimation;   a tire slip angle estimator for generating a tire slip angle estimation based on the vehicle information input and the vehicle side slip angle estimation; and   an axle cornering stiffness estimator for generating an axle cornering stiffness estimation based on the tire slip angle estimation and the axial force component estimation.   
     
     
         14 . The tire wear state estimation system of  claim 12 , wherein the axle cornering stiffness estimator comprises a recursive least squares algorithm with forgetting factor based on a polynomial model capturing a dependency between axle force component estimation and the tire slip angle estimation. 
     
     
         15 . A method of tire wear state estimation comprising:
 affixing a tire pressure measuring device to a vehicle-supporting tire, the pressure measuring device having at least one pressure sensor measuring a tire inflation pressure within a tire cavity;   measuring tire load;   measuring tire cornering stiffness;   determining a tire identification; and   estimating a tire wear state based upon inputs comprising the tire inflation pressure, the tire load, the tire cornering stiffness, and the tire identification.   
     
     
         16 . The method of  claim 15 , wherein measuring the tire cornering stiffness comprises:
 utilizing an axle force estimator receiving vehicle information input from at least one vehicle-based sensor and operative to generate an axial force component estimation;   utilizing a vehicle side slip angle estimator to generate a vehicle side slip angle estimation;   utilizing a tire slip angle estimator for generating a tire slip angle estimation based on the vehicle information input and a vehicle side slip angle estimation; and   an axle cornering stiffness estimator for generating an axle cornering stiffness estimation based on the tire slip angle estimation and the axial force component estimation.   
     
     
         17 . The method of  claim 16 , wherein further comprising utilizing in the axle cornering stiffness estimator a recursive least squares algorithm with forgetting factor based on a polynomial model capturing a dependency between axle force component estimation and the tire slip angle estimation.