A brake fluid pressure control device for a includes a wheel speed acquisition device that acquires a wheel speed, a slippage amount calculation device that calculates a wheel slippage amount, and a bad road determination device that determines whether a road surface of travel is a bad road. The bad road determination device determines whether the road surface of travel is a bad road using a bad road determination threshold value, and a value that relates to wheel behavior that is calculated based at least upon the wheel speed. The bad road determination threshold value is modified according to the wheel slippage amount. The present invention can appropriately set a bad road determination threshold value that is in accordance with a slippage amount, which corresponds to braking power, and can improve bad road determination precision without depending on variation in change of wheel speed.

A brake fluid pressure control device for a includes a wheel speed acquisition device that acquires a wheel speed, a slippage amount calculation device that calculates a wheel slippage amount, and a bad road determination device that determines whether a road surface of travel is a bad road. The bad road determination device determines whether the road surface of travel is a bad road using a bad road determination threshold value, and a value that relates to wheel behavior that is calculated based at least upon the wheel speed. The bad road determination threshold value is modified according to the wheel slippage amount. The present invention can appropriately set a bad road determination threshold value that is in accordance with a slippage amount, which corresponds to braking power, and can improve bad road determination precision without depending on variation in change of wheel speed.

A brake fluid pressure control device for a vehicle includes a wheel speed acquisition device that acquires a wheel speed, an estimated vehicle body speed calculation device that calculates an estimated vehicle body speed on the basis of the wheel speed, and a bad road determination device that determines whether a road surface of travel is a bad road. The brake fluid pressure control device for a vehicle can provide hydraulic control of a brake fluid that is used in wheel brakes, and the bad road determination device determines whether the road surface of travel is a bad road on the basis of the deviation between the estimated vehicle body speed and the wheel speed. The present invention can detect phenomena particular to bad roads, and can more accurately perform bad road determination, and allows for the improvement of control such as ABS control.

A brake fluid pressure control device for a vehicle includes a wheel speed acquisition device that acquires a wheel speed, an estimated vehicle body speed calculation device that calculates an estimated vehicle body speed on the basis of the wheel speed, and a bad road determination device that determines whether a road surface of travel is a bad road. The brake fluid pressure control device for a vehicle can provide hydraulic control of a brake fluid that is used in wheel brakes, and the bad road determination device determines whether the road surface of travel is a bad road on the basis of the deviation between the estimated vehicle body speed and the wheel speed. The present invention can detect phenomena particular to bad roads, and can more accurately perform bad road determination, and allows for the improvement of control such as ABS control.

A brake fluid pressure control device for a vehicle that includes a wheel speed obtaining device to obtain wheel speed, and a vehicle body deceleration calculating means to calculate a vehicle body deceleration on the basis of the wheel speed. If a condition is satisfied in which the vehicle body deceleration continues to stay at a low rate of less than or equal to a predetermined threshold value for a predetermined period of time, the pressure increasing rate in pressure increasing control is altered to a higher value than before the condition is satisfied. The brake fluid pressure of a brake caliper can quickly be brought close to the fluid pressure of a master cylinder. Therefore, it is possible to improve the brake responsiveness when the brake is re-operated by the driver during the ABS control, thereby reducing the driver's feeling of wrongness and strangeness.

A brake fluid pressure control device for a vehicle that includes a wheel speed obtaining device to obtain wheel speed, and a vehicle body deceleration calculating means to calculate a vehicle body deceleration on the basis of the wheel speed. If a condition is satisfied in which the vehicle body deceleration continues to stay at a low rate of less than or equal to a predetermined threshold value for a predetermined period of time, the pressure increasing rate in pressure increasing control is altered to a higher value than before the condition is satisfied. The brake fluid pressure of a brake caliper can quickly be brought close to the fluid pressure of a master cylinder. Therefore, it is possible to improve the brake responsiveness when the brake is re-operated by the driver during the ABS control, thereby reducing the driver's feeling of wrongness and strangeness.

A brake fluid pressure control device for a vehicle that can perform fluid pressure control on the brake fluid pressure applied to wheel brakes. It is determined whether the pressure increasing time in the current pressure increasing control exceeds determination time which is set on the basis of the pressure increasing time in past pressure increasing control. If the pressure increasing time in the current pressure increasing control exceeds the determination time, it is determined that the road surface on which the vehicle is travelling has changed from the road surface with a low coefficient of friction to the road surface with a high coefficient of friction.

A brake fluid pressure control device for a vehicle that can perform fluid pressure control on the brake fluid pressure applied to wheel brakes. It is determined whether the pressure increasing time in the current pressure increasing control exceeds determination time which is set on the basis of the pressure increasing time in past pressure increasing control. If the pressure increasing time in the current pressure increasing control exceeds the determination time, it is determined that the road surface on which the vehicle is travelling has changed from the road surface with a low coefficient of friction to the road surface with a high coefficient of friction.

One embodiment provides a vehicle brake hydraulic controller including: an antilock braking controlling module configured to perform an antilock braking control in which a brake hydraulic pressure applied to wheel brakes is reduced under the condition that a slip-related amount has reached a pressure reduction threshold value; and a turning judging module configured to judge whether a vehicle is turning based on a steering angle, wherein, when the antilock braking control is performed and in the case that the turning judging module judges that the vehicle is turning, the antilock braking controlling module performs a turning pressure reduction control so as to: change the pressure reduction threshold values to be more easily reached by the slip-related amount than at the time of straight running; and change the pressure reduction amounts to be larger than that at the time of straight running.

A tire force estimation system includes a sensor, a sensor information acquisition unit, and a tire force calculator. The sensor measures a physical quantity of a tire. The sensor information acquisition unit acquires the physical quantity measured by the sensor. The tire force calculator includes an arithmetic model for calculating tire force F based on the physical quantity, and calculates the tire force F by inputting the physical quantity acquired by the sensor information acquisition unit into the arithmetic model.