Patent ID: 8224546

Claim:
An ABS control system for providing ABS control on a split road surface, which comprises: a plurality of wheels including front and rear wheels on right and left sides of the vehicle, one of the right and left sides on a low μ road surface side of the vehicle, and another of the right and left sides being on a high μ road surface side of the vehicle; a plurality of wheel cylinders respectively supplying braking pressure to brakes arranged to stop rotation of the wheels; a control unit including a pressure decrease mode that continues decreasing a pressure in a respective wheel cylinder corresponding to a respective wheel, the control unit: calculating slip ratios for the rear wheels of the vehicle and identifying a rear wheel on the low μ road surface side of the vehicle and a rear wheel on the high μ road surface side of the vehicle, comparing the slip ratio of the rear wheel identified as on the low μ road surface side of the vehicle to a first threshold value, comparing the slip ratio of the rear wheel identified as on the high μ road surface side of the vehicle to a second threshold value, the second threshold value being smaller than the first threshold value, initiating a select low control, when the slip ratio of the rear wheel identified as on the low μ road surface side of the vehicle exceeds the first threshold value and the slip ratio of the rear wheel identified as on the high μ road surface side does not exceed the second threshold value, by simultaneously executing a pressure decrease mode by continuing decreasing the pressure in wheel cylinders for the rear wheel identified as on the low μ road surface side of the vehicle and for the rear wheel identified as on the high μ road surface side of the vehicle, and initiating a select high μ road control, when the slip ratio of the rear wheel identified as on the low μ road surface side of the vehicle does not exceed the first threshold value and the slip ratio of the rear wheel identified as on the high μ road surface side of the vehicle exceeds the second threshold value, by simultaneously executing the pressure decrease mode by continuing decreasing the pressure in wheel cylinders for the rear wheel identified as on the low μ road surface side of the vehicle and for the rear wheel identified as on the high μ road surface side of the vehicle.