Brake control apparatus

1. A brake control apparatus comprising:

a master cylinder arranged to raise an internal pressure of a wheel cylinder of a vehicle;

a booster arranged to raise the internal pressure of the wheel cylinder by operating the master cylinder by an electric motor in accordance with or independently of operation of an input device of the vehicle;

a pressure regulator provided with a hydraulic pressure source, and arranged to raise the internal pressure of the wheel cylinder independently of operation of the master cylinder;

a control section including:

a first controller connected for signal communication to the booster, and configured to control the booster; and

a second controller connected for signal communication to the pressure regulator, and configured to control the pressure regulator,

the control section being configured to:

detect as a first state of malfunction at least one of a state of malfunction in which it is impossible to normally drive the electric motor of the booster and a state of malfunction of a processor of the first controller;

detect as a second state of malfunction a state of malfunction in which it is possible to continue to perform control by the booster;

select in response to detection of the second state of malfunction a booster-based backup mode in which the first controller controls the internal pressure of the wheel cylinder by operating the booster;

select in response to detection of the first state of malfunction a pressure-regulator-based backup mode in which the second controller controls the internal pressure of the wheel cylinder by operating the pressure regulator; and

control the internal pressure of the wheel cylinder in the selected backup mode; and

a plurality of sensors arranged to collect information used to measure an amount of operation of the input device,

wherein the control section is further configured to:

detect that at least one of the sensors is in a state of malfunction; and

select the booster-based backup mode and control the internal pressure of the wheel cylinder by operating the booster by the first controller in accordance with an output of a normal one or set of the sensors in response to detecting that at least one of the sensors is in a state of malfunction,

wherein:

the master cylinder includes a piston arranged to raise an internal pressure of the master cylinder by being moved by the electric motor;

the sensors include a master cylinder pressure sensor arranged to measure an internal pressure of the master cylinder;

the first controller is configured to:

perform a feedback control of the electric motor during automatic braking control so as to conform the internal pressure of the master cylinder measured by the master cylinder pressure sensor to a desired value for automatic braking;

set a desired displacement of the piston of the master cylinder in accordance with the desired value for automatic braking;

estimate an actual displacement of the piston of the master cylinder in accordance with an amount of rotation of the electric motor;

detect that the master cylinder pressure sensor is in a state of malfunction; and

control the internal pressure of the wheel cylinder in the booster-based backup mode by inhibiting the feedback control and operating the booster so as to conform the estimated actual displacement of the piston to the desired displacement under control of automatic braking, in response to detecting that the master cylinder pressure sensor is in a state of malfunction.

2. A brake control apparatus comprising:

a master cylinder arranged to raise an internal pressure of a wheel cylinder of a vehicle;

a booster arranged to raise the internal pressure of the wheel cylinder by operating the master cylinder by an electric motor in accordance with or independently of operation of an input device of the vehicle;

a pressure regulator provided with a hydraulic pressure source, and arranged to raise the internal pressure of the wheel cylinder independently of operation of the master cylinder;

a control section including:

a first controller connected for signal communication to the booster, and configured to control the booster; and

a second controller connected for signal communication to the pressure regulator, and configured to control the pressure regulator,

the control section being configured to:

detect as a first state of malfunction at least one of a state of malfunction in which it is impossible to normally drive the electric motor of the booster and a state of malfunction of a processor of the first controller;

detect as a second state of malfunction a state of malfunction in which it is possible to continue to perform control by the booster;

select in response to detection of the second state of malfunction a booster-based backup mode in which the first controller controls the internal pressure of the wheel cylinder by operating the booster;

select in response to detection of the first state of malfunction a pressure-regulator-based backup mode in which the second controller controls the internal pressure of the wheel cylinder by operating the pressure regulator; and

control the internal pressure of the wheel cylinder in the selected backup mode; and

a plurality of sensors arranged to collect information used to measure an amount of operation of the input device,

wherein the control section is further configured to:

detect that at least one of the sensors is in a state of malfunction; and

select the booster-based backup mode and control the internal pressure of the wheel cylinder by operating the booster by the first controller in accordance with an output of a normal one or set of the sensors in response to detecting that at least one of the sensors is in a state of malfunction,

wherein:

the master cylinder includes a piston arranged to raise an internal pressure of the master cylinder by being moved by the electric motor;

the sensors include:

a stroke sensor arranged to measure a stroke of the input device that is a brake pedal; and

a master cylinder pressure sensor arranged to measure an internal pressure of the master cylinder;

the first controller is configured to:

perform a feedback control of the electric motor so as to conform the internal pressure of the master cylinder measured by the master cylinder pressure sensor to a desired fluid pressure;

set a desired displacement of the piston of the master cylinder in accordance with the stroke of the brake pedal measured by the stroke sensor;

detect that the master cylinder pressure sensor is in a state of malfunction; and

control the internal pressure of the wheel cylinder by adjusting a displacement of the piston to the desired displacement by the electric motor in accordance with the measured stroke of the brake pedal, in response to detecting that the master cylinder pressure sensor is in a state of malfunction.

3. A brake control apparatus comprising:

a master cylinder arranged to raise an internal pressure of a wheel cylinder of a vehicle in accordance with operation of an input device of the vehicle;

a booster arranged to raise the internal pressure of the wheel cylinder by operating the master cylinder independently of operation of the input device;

a pressure regulator provided with a hydraulic pressure source, and arranged to raise the internal pressure of the wheel cylinder independently of operation of the master cylinder;

a control section including:

a first controller connected for signal communication to the booster, and configured to control the booster; and

a second controller connected for signal communication to the pressure regulator, and configured to control the pressure regulator,

the control section is configured to:

detect that at least one of the booster and the first controller is in a state of malfunction;

select a backup mode in accordance with the state of malfunction of the booster, wherein the backup modes restrict operation of the booster; and

control the internal pressure of the wheel cylinder by operating the pressure regulator in the selected backup mode; and

a plurality of sensors arranged to collect information used to measure an amount of operation of the input device,

wherein the first controller is configured to:

detect that at least one of the sensors is in a state of malfunction; and

control the internal pressure of the wheel cylinder by operating the booster in accordance with an output of a normal one or set of the sensors in response to detecting that at least one of the sensors is in a state of malfunction;

wherein:

the master cylinder includes a piston arranged to raise an internal pressure of the master cylinder;

the sensors include a master cylinder pressure sensor arranged to measure an internal pressure of the master cylinder;

the booster includes an electric motor arranged to operate the master cylinder;

the control section is further configured to:

set a desired displacement of the piston of the master cylinder in accordance with a desired value of the internal pressure of the master cylinder; and

estimate an actual displacement of the piston of the master cylinder in accordance with an amount of rotation of the electric motor; and

the first controller is configured to:

detect that the master cylinder pressure sensor is in a state of malfunction; and

control the internal pressure of the wheel cylinder by operating the booster so as to conform the estimated actual displacement of the piston to the desired displacement independently of operation of the input device under control of automatic braking, in response to detecting that the master cylinder pressure sensor is in a state of malfunction.

4. A brake control apparatus comprising:

a master cylinder arranged to raise an internal pressure of a wheel cylinder of a vehicle in accordance with operation of an input device of the vehicle;

a booster arranged to raise the internal pressure of the wheel cylinder by operating the master cylinder independently of operation of the input device;

a pressure regulator provided with a hydraulic pressure source, and arranged to raise the internal pressure of the wheel cylinder independently of operation of the master cylinder;

a control section including:

a first controller connected for signal communication to the booster, and configured to control the booster; and

a second controller connected for signal communication to the pressure regulator, and configured to control the pressure regulator,

the control section is configured to:

detect that at least one of the booster and the first controller is in a state of malfunction;

select a backup mode in accordance with the state of malfunction of the booster, wherein the backup modes restrict operation of the booster; and

control the internal pressure of the wheel cylinder by operating the pressure regulator in the selected backup mode; and

a plurality of sensors arranged to collect information used to measure an amount of operation of the input device,

wherein the first controller is configured to:

detect that at least one of the sensors is in a state of malfunction; and

control the internal pressure of the wheel cylinder by operating the booster in accordance with an output of a normal one or set of the sensors in response to detecting that at least one of the sensors is in a state of malfunction;

wherein:

the master cylinder includes a piston arranged to raise an internal pressure of the master cylinder;

the input device includes a brake pedal;

the sensors include:

a master cylinder pressure sensor arranged to measure an internal pressure of the master cylinder; and

a stroke sensor arranged to measure a stroke of the brake pedal;

the booster includes an electric motor arranged to operate the master cylinder;

the control section is further configured to:

set a desired displacement of the piston of the master cylinder in accordance with a desired value of the internal pressure of the master cylinder; and

estimate an actual displacement of the piston of the master cylinder in accordance with an amount of rotation of the electric motor; and

the first controller is configured to:

detect that the master cylinder pressure sensor is in a state of malfunction; and

control the internal pressure of the wheel cylinder by adjusting the displacement of the piston by the booster in accordance with the measured stroke of the brake pedal so as to raise the internal pressure of the master cylinder by a constant amplification factor, in response to detecting that the master cylinder pressure sensor is in a state of malfunction.