Patent ID: 11904861
Assignee: KIA CORPORATION
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 11:
12. A method of estimating a road surface friction coefficient, the method comprising:
collecting, by a processor, information for determining a speed of a vehicle from sensors mounted in the vehicle;
determining, by the processor, whether to estimate the road surface friction coefficient by determining whether the vehicle is in an inertial driving state, according to the collected information;
arbitrarily adding, by the processor, a braking force causing a wheel speed difference to an axle of the vehicle, to which the braking force is applied, and adding a driving force for canceling the braking force, to an axle of the vehicle to which the driving force is applied, when the processor determines that the vehicle is the inertial driving state; and
estimating, by the processor, a state of the road surface friction coefficient by the wheel speed difference caused by the arbitrarily added braking force,
wherein the estimating of the road surface friction coefficient includes:
receiving wheel speeds of the vehicle from a wheel coupled to the axle, to which the braking force is applied, and a wheel coupled to the axle, to which the driving force is applied;
determining a magnitude of the wheel speed difference between the wheel speeds; and
determining a value of the wheel speed difference as a corrected wheel speed difference index value by multiplying the wheel speed difference, which is determined in the determining of the magnitude of the wheel speed difference between the wheel speeds, by a predetermined correction coefficient, depending on a magnitude of a target driving torque acting on the axle, to which the driving force is applied.