US 12,269,478 B2
Method of estimating maximum road friction coefficient
Hae Ryong Choi, Seoul (KR); Dong Yoon Hyun, Seoul (KR); and Seung Han You, Seoul (KR)
Assigned to Hyundai Motor Company, Seoul (KR); Kia Corporation, Seoul (KR); and Korea University of Technology and Education Industry-University Cooperation Foundation, Cheonan-si (KR)
Filed by Hyundai Motor Company, Seoul (KR); Kia Corporation, Seoul (KR); and Korea University of Technology and Education Industry-University Cooperation Foundation, Cheonan-si (KR)
Filed on Oct. 4, 2021, as Appl. No. 17/492,919.
Claims priority of application No. 10-2020-0176152 (KR), filed on Dec. 16, 2020.
Prior Publication US 2022/0185293 A1, Jun. 16, 2022
Int. Cl. B60W 40/068 (2012.01); B60W 10/18 (2012.01); B60W 40/107 (2012.01); B60W 40/109 (2012.01); B60W 40/114 (2012.01)
CPC B60W 40/068 (2013.01) [B60W 10/18 (2013.01); B60W 40/107 (2013.01); B60W 40/109 (2013.01); B60W 40/114 (2013.01); B60W 2520/14 (2013.01); B60W 2520/263 (2013.01); B60W 2520/28 (2013.01); B60W 2520/30 (2013.01); B60W 2540/18 (2013.01); B60W 2552/40 (2020.02); B60W 2710/18 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of estimating a maximum road friction coefficient, the method comprising:
collecting, by a processor, operation information related to a vehicle;
differentially controlling, by the processor, at least one of driving torque and braking torque of a front wheel and a rear wheel of the vehicle within a range of a driving request, a braking request, or a request to maintain a constant speed of the vehicle for estimating the maximum road friction coefficient;
compensating, by the processor, slip due to tire force in the front wheel and the rear wheel;
determining, by the processor, a wheel speed difference ratio of the front wheel and the rear wheel according to a speed of the front wheel and a speed of the rear wheel where the slip due to tire force is compensated; and
estimating, by the processor, the maximum road friction coefficient according to the wheel speed difference ratio and a current road friction coefficient of each wheel including the front wheel and the rear wheel,
wherein, in determining the wheel speed difference ratio, a speed of each wheel is compensated for a steering angle, a yaw rate, and a lateral speed of the vehicle, and
wherein the wheel speed difference ratio is determined based on the speed of each wheel compensated for the slip due to tire force, the lateral speed, the steering angle, and the yaw rate of the vehicle based on a center of gravity of the vehicle and a longitudinal speed of the vehicle.