Patent ID: 8444230

Claim:
A vehicle motion control apparatus provided at a brake system including a master cylinder, wheel cylinders respectively provided at plural wheels of a vehicle, solenoid valves respectively provided between the master cylinder and the corresponding wheel cylinders and an electric motor operating a pump for controlling a supply of brake fluid to the wheel cylinder, the vehicle motion control apparatus applying a hydraulic pressure to the wheel cylinders at a predetermined pressure increasing rate based on a condition of the vehicle regardless of operation of a brake operation member by an operator of the vehicle, the vehicle motion control apparatus comprising: hydraulic pressure applying means for applying the hydraulic pressure to any one of the wheel cylinders by operating the pump with the electric motor to supply brake fluid to a master cylinder side of the solenoid valve for the corresponding wheel cylinder and by controlling an operation of the solenoid valve to allow brake fluid to flow from the solenoid valve to a wheel cylinder side of the solenoid valve so that a target pressure increasing rate specified on a basis of the condition of the vehicle is satisfied even when the operator of the vehicle does not operate the brake operation member; motor controlling means for controlling an output of the electric motor to be reduced in accordance with a condition of a road surface, on which the vehicle drives, when the hydraulic pressure applying means applies the hydraulic pressure to the wheel cylinder; means for determining that the output of the electric motor has been reduced by the motor controlling means; and valve controlling means for controlling the operation of the solenoid valve to increase an amount of brake fluid allowed to flow from the solenoid valve by the operation of the solenoid valve whenever the means for determining determines that of the output of the electric motor has been reduced to maintain the target pressure increasing rate when the motor controlling means controls the electric motor to reduce the output, wherein when the motion control apparatus applies a hydraulic pressure to the wheel cylinders at the predetermined pressure increase rate when the operator of the vehicle does not operate the brake operation member, a reduction of the pressure increasing rate relative to the wheel cylinders caused by a reduction of the output of the electric motor by the motor controlling means is compensated with an increase of the pressure increasing rate by controlling the solenoid valve by the valve controlling means to increase the amount of brake fluid allowed to flow to the wheel cylinders.