A hydraulic brake system is configured such that a pressure of a working fluid from a high-pressure-source device is adjusted by electromagnetic pressure-increase and pressure-decrease linear valves and such that a brake device generates a braking force having a magnitude that depends on the pressur
A hydraulic brake system is configured such that a pressure of a working fluid from a high-pressure-source device is adjusted by electromagnetic pressure-increase and pressure-decrease linear valves and such that a brake device generates a braking force having a magnitude that depends on the pressure adjusted by the linear valves, wherein the following controls are selectively executable, as a control of the energizing currents supplied to the linear valves, a feedback control based on a difference between an actual braking-force index and a target braking-force index; and a feedforward control based on the target braking-force index executed by placing each valve in a valve equilibrium state, wherein, in the feedforward control, an energizing current is supplied to at least one of the two linear valves, the energizing current being larger than that according to a preset relationship between a braking-force index and an energizing current in the valve equilibrium state.
대표청구항▼
1. A hydraulic brake system for braking a vehicle, comprising: a high-pressure-source device configured to supply a working fluid that is highly pressurized;an electromagnetic pressure-increase linear valve and an electromagnetic pressure-decrease linear valve configured to adjust a pressure of the
1. A hydraulic brake system for braking a vehicle, comprising: a high-pressure-source device configured to supply a working fluid that is highly pressurized;an electromagnetic pressure-increase linear valve and an electromagnetic pressure-decrease linear valve configured to adjust a pressure of the working fluid supplied from the high-pressure-source device to an adjusted pressure;a brake device provided in a wheel and configured to receive the working fluid having the adjusted pressure or a pressure in accordance with the adjusted pressure and to generate a braking force having a magnitude in accordance with the pressure of the received working fluid;a braking-force index detector configured to detect a braking-force index indicative of the braking force; anda controller configured to control the braking force generated by the brake device by controlling an energizing current supplied to each of the pressure-increase linear valve and the pressure-decrease linear valve,wherein the controller is configured to selectively execute one of: (a) a feedback control in which a feedback component that is a component of the energizing current supplied to each of the pressure-increase linear valve and the pressure-decrease linear valve is determined based on a difference between an actual braking-force index detected by the braking-force index detector and a target braking-force index that is a target of the braking-force index in a control, so as to lessen the difference and in which the energizing current that contains the feedback component is supplied to each of the pressure-increase linear valve and the pressure-decrease linear valve; and (b) a feedforward control in which a feedforward component that is a component of the energizing current supplied to each of the pressure-increase linear valve and the pressure-decrease linear valve is determined based on the target braking-force index, without determining the difference between the actual braking-force index detected by the braking-force index detector and the target braking-force index, so as to place each of the pressure-increase linear valve and the pressure-decrease linear valve in a valve equilibrium state that is a boundary between a valve open state and a valve closed state and in which the energizing current that contains the feedforward component is supplied to each of the pressure-increase linear valve and the pressure-decrease linear valve, andwherein the controller is configured to determine, when the feedforward control is executed, the energizing current supplied to at least one of the pressure-increase linear valve and the pressure-decrease linear valve so as to cause the braking force to be larger than the braking force caused when the energizing current is determined in an instance in which the feedforward component is set according to a preset relationship between the braking-force index and the energizing current in the valve equilibrium state. 2. The hydraulic brake system according to claim 1, wherein the controller is configured to determine, as the feedforward component, the energizing current according to the preset relationship between the braking-force index and the energizing current in the valve equilibrium state based on the actual braking-force index detected by the braking-force index detector and is configured to supply an energizing current that contains the determined feedforward component and the feedback component to each of the pressure-increase linear valve and the pressure-decrease linear valve, in the feedback control. 3. The hydraulic brake system according to claim 1, wherein the controller is configured to execute the feedback control in a case where the braking-force index detector operates normally and is configured to execute the feedforward control in a case of a failure of the braking-force index detector. 4. The hydraulic brake system according to claim 1, wherein the controller is configured to detect, in the feedback control, a deviation of an actual relationship between the braking-force index and the energizing current in the valve equilibrium state from the preset relationship, andwherein the controller is configured to determine, when the feedforward control is executed, the energizing current supplied to the at least one of the pressure-increase linear valve and the pressure-decrease linear valve so as to be equal to an energizing current in an instance in which the feedforward component is determined according to a relationship between the braking-force index and the energizing current in the valve equilibrium state at the time of occurrence of the detected deviation. 5. The hydraulic brake system according to claim 1, wherein the preset relationship between the braking-force index and the energizing current in the valve equilibrium state falls within a preset specified range, andwherein the controller is configured to determine, when the feedforward control is executed, the energizing current supplied to the at least one of the pressure-increase linear valve and the pressure-decrease linear valve so as to be equal to an energizing current in an instance in which the feedforward component is determined according to a relationship corresponding to a lower limit of the braking force in the specified range. 6. The hydraulic brake system according to claim 1, wherein the preset relationship between the braking-force index and the energizing current in the valve equilibrium state falls within a preset specified range, andwherein the controller is configured to determine, when the feedforward control is executed, the energizing current supplied to the at least one of the pressure-increase linear valve and the pressure-decrease linear valve so as to be equal to an energizing current in an instance in which the feedforward component is determined according to a relationship that is shifted toward a lower limit of the braking force with respect to a middle of the braking force between the lower limit and an upper limit of the braking force in the specified range. 7. The hydraulic brake system according to claim 1, wherein the controller is configured to determine, when the feedforward control is executed, the energizing current supplied to the at least one of the pressure-increase linear valve and the pressure-decrease linear valve so as to be equal to a value that is shifted, by a given current amount, toward the side on which the braking force is large, as compared with the energizing current in an instance in which the feedforward component is determined according to the preset relationship between the braking-force index and the energizing current in the valve equilibrium state. 8. The hydraulic brake system according to claim 1, wherein each of the pressure-increase linear valve and the pressure-decrease linear valve has (A) a valve seat, (B) a valve member configured to be seated on the valve seat so as to effectuate the valve closed state and configured to be separated away from the valve seat so as to effectuate the valve open state, (C) an elastic biasing mechanism configured to bias, by an elastic biasing force, the valve member in one of a direction in which the valve member is seated on the valve seat and a direction in which the valve member is separated away from the valve seat, and (D) an electromagnetic coil configured to generate an electromagnetic acting force by the energizing current supplied thereto and configured to bias the valve member in the other of the direction in which the valve member is seated on the valve seat and the direction in which the valve member is separated away from the valve seat, the valve equilibrium state being effectuated by a balance among the elastic biasing force, the electromagnetic acting force, and a pressure-difference-based acting force that acts on the valve member in dependence on the adjusted pressure, andwherein the controller is configured to determine, in the feedforward control, the energizing current supplied to the at least one of the pressure-increase linear valve and the pressure-decrease linear valve so as to be equal to an energizing current in an instance in which the feedforward component is determined according to a relationship between the braking-force index and the energizing current in the valve equilibrium state when the elastic biasing force is changed to a value different from a preset value. 9. The hydraulic brake system according to claim 1, wherein the controller is configured to judge whether the braking force is larger than a set degree and to change the energizing current supplied to the at least one of the pressure-increase linear valve and the pressure-decrease linear valve to a value that is shifted toward a side on which the braking force is small where it is judged that the braking force is larger than the set degree, in the feedforward control. 10. The hydraulic brake system according to claim 9, wherein the controller is configured such that, when the energizing current supplied to the at least one of the pressure-increase linear valve and the pressure-decrease linear valve is changed to the value that is shifted toward the side on which the braking force is small, the energizing current is changed to the value that is shifted by a current amount smaller than a current amount when shifted toward the side on which the braking force is large, in the feedforward control. 11. The hydraulic brake system according to claim 9, wherein the controller is configured to judge, based on a change in the pressure of the working fluid supplied from the high-pressure-source device, whether the braking force is larger than the set degree, in the feedforward control. 12. The hydraulic brake system according to claim 1, further comprising a pressure regulator having a pilot chamber and configured to regulate the pressure of the working fluid supplied from the high-pressure-source device to a pressure in accordance with a pressure of the working fluid in the pilot chamber and to supply the working fluid whose pressure is regulated, wherein the pressure-increase linear valve is disposed between the high-pressure-source device and the pilot chamber for increasing the pressure of the working fluid in the pilot chamber, and the pressure-decrease linear valve is disposed between the pilot chamber and a low-pressure source for decreasing the pressure of the working fluid in the pilot chamber, whereby the pressure of the working fluid in the pilot chamber is adjusted to the adjusted pressure, andwherein the brake device is configured to receive the working fluid supplied from the pressure regulator or the working fluid having a pressure in accordance with a pressure of the working fluid supplied from the pressure regulator and to generate the braking force having a magnitude in accordance with the pressure of the received working fluid. 13. The hydraulic brake system according to claim 12, further comprising a master cylinder device to which a brake operation member is connected and which is configured to receive the working fluid supplied from the pressure regulator and to supply, to the brake device, the working fluid that is pressurized depending on the pressure of the received working fluid to a pressure in accordance with the pressure of the received working fluid, without depending on a brake operation force applied to the brake operation member by a driver, wherein the hydraulic brake system is configured to permit the brake device to generate the braking force having a magnitude in accordance with the pressure of the working fluid supplied from the master cylinder device to the brake device. 14. The hydraulic brake system according to claim 1, further comprising a master cylinder device to which a brake operation member is connected, the master cylinder device being configured to receive the working fluid whose pressure is adjusted to the adjusted pressure by the pressure-increase linear valve and the pressure-decrease linear valve and configured to supply, to the brake device, the working fluid that is pressurized depending on the pressure of the received working fluid to a pressure in accordance with the pressure of the received working fluid, without depending on a brake operation force applied to the brake operation member by a driver, wherein the hydraulic brake system is configured to permit the brake device to generate the braking force having a magnitude in accordance with the pressure of the working fluid supplied from the master cylinder device to the brake device.
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이 특허에 인용된 특허 (4)
Ohkubo, Masayasu; Mizutani, Yasuji; Sakazaki, Kazuyoshi, Brake control apparatus and control method thereof.
Hiroshi Isono JP; Yasuji Mizutani JP, Vehicle braking system having devices for controlling fluid flows between pressurizing and assisting chambers of master cylinder and pressure source and reservoir.
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