Braking control device for vehicle and braking control method for vehicle

Patent metadata

Field	Value
Publication number	US-9434364-B2
Application number	US-201213985127-A
Country	US
Kind code	B2
Filing date	Feb 17, 2012
Priority date	Feb 18, 2011
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

A brake ECU determines whether or not interference-based vibration components are included in a vehicle body deceleration (DV) (steps S 74 , S 76 ). Then, in the case of a positive determination (YES in step S 74 or step S 76 ), the brake ECU makes a comparison with when the determination is not positive, and revises a first deceleration determination value (DV_st) to be a larger value (step S 79 ). If the vehicle body deceleration value (DV) exceeds the first deceleration determination value (DV_st) and a G sensor value (G) exceeds a second deceleration determination value (G_st) (YES in steps S 84 and S 89 ), the brake ECU initiates auxiliary control.

First claim

The invention claimed is:

1. A braking control device for a vehicle, comprising:
a first deceleration calculation unit that calculates a first estimated vehicle body deceleration by using a detection signal of a wheel speed sensor arranged on the vehicle;
a second deceleration calculation unit that calculates a second estimated vehicle body deceleration by using a detection signal of a vehicle body acceleration sensor arranged on the vehicle, the vehicle body acceleration sensor being more distant from a wheel of the vehicle than the wheel speed sensor;
an assist control unit that initiates an assist control, which assists increasing of a braking force that is applied to the wheel based on operation of a brake pedal of the vehicle so that the braking force is greater than a braking force applied to the wheel just by the driver's operation on the brake pedal, when the first estimated vehicle body deceleration exceeds a first deceleration determination value and the second estimated vehicle body deceleration exceeds a second deceleration determination value during operation of the brake pedal of the vehicle;
an outer disturbance determination unit that determines whether a vibration component based on outer disturbance is included in the first estimated vehicle body deceleration; and
a reference value correction unit that corrects the first deceleration determination value to a greater value when the first estimated vehicle body deceleration includes a vibration component based on outer disturbance than when such is not the case, wherein
when the second estimated vehicle body deceleration is greater than the sum of the first estimated vehicle body deceleration and a deceleration specified value or when the first estimated vehicle body deceleration has a negative value, the outer disturbance determination unit determines that the first estimated vehicle body deceleration includes a vibration component based on outer disturbance.

2. The braking control device for a vehicle according to claim 1 , further comprising a bad road index acquisition unit that acquires a bad road index that numerically indicates the unevenness degree of the road surface along which the vehicle is traveling, wherein
the outer disturbance determination unit determines whether or not the road surface along which the vehicle is traveling is a bad road based on the bad road index, and
the reference value correction unit corrects the first deceleration determination value to a greater value when the outer disturbance determination unit determines that the road surface is a bad road than when such is not the case.

3. The braking control device for a vehicle according to claim 2 , further comprising an amplitude calculator that calculates an amplitude of the first estimated vehicle body deceleration,
wherein, in a case in which the outer disturbance determination unit determines that the road surface is not a bad road, the reference value correction unit corrects the first deceleration determination value to a greater value when the amplitude is great than when the amplitude is small.

4. The braking control device for a vehicle according to claim 3 , wherein, in a case in which the outer disturbance determination unit determines that the road surface is not a bad road, the reference value correction unit does not perform correction of the first deceleration determination value based on the amplitude if the amplitude is less than a preset amplitude reference value.

5. The braking control device for a vehicle according to claim 2 , wherein, in the assist control, the assist control unit sets an increasing speed of the braking force applied to the vehicle wheel to a lower value when the reference value correction unit has corrected the first deceleration determination value than when such is not the case.

6. The braking control device for a vehicle according to claim 1 , wherein
during a preset deceleration specified time, the reference value correction unit corrects the first deceleration determination value to a greater value when the first estimated vehicle body deceleration includes a vibration component based on outer disturbance than when such is not the case.

7. The braking control device for a vehicle according to claim 1 , wherein
when receiving a signal indicating that a transmission mounted in the vehicle is about to be downshifted from a transmission control unit, which controls the transmission, the outer disturbance determination unit determines that the transmission is about to be downshifted, and
during a gear shifting specified time, the reference value correction unit corrects the first deceleration determination value to a greater value when it is determined that the transmission is about to be downshifted than when such is not the case.

8. The braking control device for a vehicle according to claim 1 , wherein
when receiving a signal indicating that a manual transmission mounted in the vehicle has been downshifted from a monitoring control device, which monitors the shift position of the transmission, the outer disturbance determination unit determines that the transmission has been downshifted,
if an accelerator operation amount is not increased when it is determined that the transmission has been downshifted, the reference value correction unit corrects the first deceleration determination value to a greater value than when it is determined that the transmission has not been downshifted, and
if the accelerator operation amount is increased when it is determined that the transmission has been downshifted, the reference value correction unit sets the first deceleration determination value to a value corresponding to a determination that the transmission has not been downshifted.

9. The braking control device for a vehicle according to claim 1 , further comprising a duration time acquisition unit that acquires a duration time of a state in which the second estimated vehicle deceleration remains greater than a high depression force determination reference value, which is set for determining whether a depression operation amount of the brake pedal is large, wherein
when the duration time is longer than or equal to a high depression force specified time, the outer disturbance determination unit determines that there is a possibility that a transmission mounted in the vehicle will be downshifted, and
the reference value correction unit corrects the first deceleration determination value to a greater value when there is a possibility that the transmission will be downshifted than when such is not the case.

10. The braking control device for a vehicle according to claim 1 , wherein
in a case in which the brake pedal is being operated, the outer disturbance determination unit determines that there is a possibility that a transmission mounted in the vehicle has been downshifted if a rotational speed of an output shaft of a drive source of the vehicle is increased without an increase in an accelerator operation amount, and
the reference value correction unit corrects the first deceleration determination value to a greater value when there is a possibility that the transmission has been downshifted than when such is not the case.

11. A braking control device for a vehicle, comprising:
a first deceleration calculation unit that calculates a first estimated vehicle body deceleration by using a detection signal of a wheel speed sensor arranged on the vehicle;
a second deceleration calculation unit that calculates a second estimated vehicle body deceleration by using a detection signal of a vehicle body acceleration sensor arranged on the vehicle, the vehicle body acceleration sensor being more distant from a wheel

Assignees

• Terasaka Masato
• Takeya Yusuke
• Tsukamoto Shinji
• Advics Co Ltd

Inventors

• Terasaka Masato
• Takeya Yusuke
• Tsukamoto Shinji

Classifications

• B60T2201/03

  Brake assistants · CPC title

• B60T17/22

  Devices for monitoring or checking brake systems; Signal devices · CPC title

• B60T7/042 Primary

  by electrical means, e.g. using travel or force sensors · CPC title

• B60T7/12

  for automatic initiation; for initiation not subject to will of driver or passenger {(limiting speed of vehicles other than rail vehicles B60K31/00)} · CPC title

• B60T8/1761 Primary

  responsive to wheel or brake dynamics, e.g. wheel slip, wheel acceleration or rate of change of brake fluid pressure · CPC title