Vehicle brake control device for an electrically driven vehicle

A vehicle brake control device for an electrically driven vehicle, comprising:

• a master cylinder that generates a master cylinder pressure in accordance with a braking operation;
• a front wheel cylinder disposed at a front wheel to supply a hydraulic pressure braking power to the front wheel;
• a rear wheel cylinder disposed at a rear wheel to supply a hydraulic pressure braking power to the rear wheel;
• a brake hydraulic pressure actuator interposed between the master cylinder and the front and rear wheel cylinders, and the brake hydraulic pressure actuator including a hydraulic pressure pump driven by a pumping motor and a differential valve for controlling the pressure difference between a wheel cylinder pressure of the front and rear wheel cylinders and the master cylinder pressure during operation of the pumping motor;
• a regenerative brake force control unit connected to an electric drive motor that is coupled to a drive wheel that is one of the front and rear wheels, the regenerative brake force control unit controlling a regenerative brake force that is generated by the electric drive motor;
• and
• a regenerative cooperative brake control unit that calculates a target deceleration of a driver's request and outputs a regenerative braking command to the regenerative brake force control unit and a fluid pressure command to a brake control unit of the brake hydraulic pressure actuator to achieve the target deceleration during the braking operation, the regenerative cooperative brake control unit calculating a sum of a base hydraulic deceleration portion derived from of the master cylinder pressure and a deceleration portion derived from the regenerative brake force, and further compensating for a shortage of the regenerative deceleration portion in the sum to achieve the target deceleration by an add-on deceleration portion generated by the brake hydraulic pressure actuator,
• the regenerative cooperative brake control unit stopping the pumping motor from operating upon determining the vehicle speed has fallen below a first predetermined vehicle speed value,
• the regenerative cooperative brake control unit setting a target deceleration value that is lower than the target deceleration and restarting the pumping motor upon determining the vehicle speed exceeding a second predetermined vehicle speed value and the braking operation is occurring while the pumping motor is in a stopped state as a result of the vehicle speed falling below the first predetermined vehicle speed value.