Brake control device

A brake control device installed to a vehicle, comprising:

• a target acceleration setting portion for determining a target acceleration which the vehicle should achieve, wherein a microcomputer serves as the target acceleration setting portion;
• and
• a braking/driving cooperative control portion for calculating, based on the target acceleration determined by the target acceleration setting portion, a required powertrain axle torque required to power the vehicle and a required brake axle torque required to brake the vehicle, transmitting the calculated required powertrain axle torque to a powertrain axle torque realizing portion which performs control so that the powertrain of the vehicle generates the required powertrain axle torque, and transmitting the calculated required brake axle torque to a brake axle torque realizing portion which performs control so that a brake device of the vehicle generates a brake pressure corresponding to the required brake axle torque, wherein a microcomputer serves as the braking/driving cooperative control portion, wherein:
• a microcomputer serves as the powertrain axle torque realizing portion,
• a microcomputer serves as the brake axle torque realizing portion,
• the target acceleration setting portion calculates, when a speed of the vehicle on an ascending slope decreases to become equal to or smaller than a border vehicular speed, a negative soft acceleration which comes closer to zero in accordance with deceleration of the vehicle, identifies the calculated soft acceleration as the target acceleration, and keeps the soft acceleration constant after the vehicular speed becomes smaller than a minimum detectable vehicular speed of the wheel speed sensor;
• the braking/driving cooperative control portion determines, at a timing at which the speed of the vehicle on the ascending slope becomes smaller than a minimum detectable vehicular speed of the wheel speed sensor, a negative initial value of the required brake axle torque, a negative final value, and a correction duration, and causes the required brake axle torque to change from the initial value to the final value during the correction duration from the timing;
• the initial value is a required brake axle torque determined based on the target acceleration;
• the final value is a torque with which the vehicle can stop at the ascending slope;
• and
• the braking/driving cooperative control portion estimates a stop time at which an actual speed of the vehicle becomes zero based on a detected vehicular speed at a limit time and a detected acceleration of the vehicle calculated by the detected vehicular speed, the limit time being a last moment of a period in which the detected vehicular speed of the vehicle detected based on a detection signal of the wheel speed sensor is equal to or larger than a minimum detectable vehicular speed, and the braking/driving cooperative control portion identifies a period from the limit time to the stop time as the correction duration.