KR20190127045A - Electric brake system and method thereof - Google Patents

Abstract

An electronic brake system is disclosed. According to an embodiment, the electronic brake system comprises: a hydraulic pressure supply device for generating hydraulic pressure using a rotation force of a motor operated by an electrical signal output from a pedal position sensor; and a motor control sensor for measuring a current and a rotation angle of the motor. The electronic brake system more comprises a control unit configured to calculate an equivalent rigidity coefficient of the electronic brake system based on the measured current and the rotation angle of the motor, and determine that the electronic brake system leaks when the calculated equivalent rigidity coefficient is smaller than a first threshold value.

Description

Electronic brake system and method

The present invention relates to an electronic brake system, and more particularly to an electronic brake system for determining the leakage of the system using a motor control sensor. It relates to an electronic brake system for generating a braking force by using.

Vehicles are equipped with a brake system for braking. Recently, various kinds of systems have been proposed for obtaining a stronger and more stable braking force.

An example of a brake system is an anti-lock brake system (ABS) to prevent wheel slippage during braking and a brake traction control system (BTCS) to prevent slippage of driving wheels during rapid start or acceleration of a vehicle. Traction Control System (ESC), Electronic Stability Control System (ESC), which maintains the vehicle's running state by controlling brake hydraulic pressure by combining anti-lock brake system and traction control.

In general, the electronic brake system includes a hydraulic pressure supply device for supplying pressure to the wheel cylinder by receiving the driver's braking intention as an electric signal from a pedal displacement sensor that detects the displacement of the brake pedal when the driver presses the brake pedal.

An electronic brake system provided with the hydraulic pressure supply device as described above is disclosed in EP 2 520 473. According to the disclosed literature, the hydraulic pressure supply device is configured to generate a braking pressure by operating a motor according to the pedaling force of the brake pedal. At this time, the braking pressure is generated by converting the rotational force of the motor into linear motion to pressurize the piston.

In addition, the brake system includes a pedal simulator that provides a feeling of pedaling to the driver by receiving hydraulic pressure according to the driver's pedaling force to measure the pedaling force of the driver.

In the electronic brake system, however, studies on how to determine when leakage has occurred have been continuously conducted.

EP 2 520 473 A1 (Honda Motor Co., Ltd.) 2012. 11. 7.

An embodiment of the present invention is to provide an electronic brake system capable of leak determination using a motor control sensor without using an additional pressure sensor.

According to an aspect of the present invention, a hydraulic pressure supply device for generating a hydraulic pressure using the rotational force of the motor operated by the electrical signal output from the pedal position sensor, and a motor control sensor for measuring the current and rotation angle of the motor. In the electronic brake system, the equivalent stiffness coefficient of the electronic brake system is calculated based on the measured current and rotation angle of the motor, and if the calculated equivalent stiffness coefficient is smaller than the first threshold value, the leakage of the electronic brake system An electronic brake system may further be provided.

In addition, the first hydraulic circuit for transmitting the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel; And a second hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel, wherein the first hydraulic circuit and the second hydraulic circuit are discharged from the hydraulic pressure supply device. Each wheel may include an inlet valve to adjust the flow rate.

In addition, when the electronic brake system is determined to be leaking, the control unit closes the inlet valve included in the first hydraulic circuit so that the flow rate is not discharged to the first hydraulic circuit, and recalculates the equivalent stiffness coefficient. If the calculated equivalent stiffness coefficient is smaller than the second threshold value larger than the first threshold value, it may be determined as a leak of the second hydraulic circuit.

The controller may open the inlet valve included in the first hydraulic circuit, close the inlet valve included in the second hydraulic circuit, if the recalculated equivalent stiffness coefficient is greater than the second threshold value. When the equivalent stiffness coefficient is recalculated and the recalculated equivalent stiffness coefficient is smaller than the second threshold value, it may be determined as a leak of the first hydraulic circuit.

The controller may determine that the electronic brake system is normal if the recalculated equivalent stiffness coefficient is greater than the second threshold value.

According to another aspect, the electronic device includes a hydraulic pressure supply device for generating a hydraulic pressure using the rotational force of the motor operated by the electrical signal output from the pedal position sensor, and a motor control sensor for measuring the current and the rotation angle of the motor. A control method of a brake system, comprising: calculating an equivalent stiffness coefficient of the electronic brake system based on a measured current and rotation angle of a motor; And if the calculated equivalent stiffness coefficient is less than the first threshold value, determining the leakage of the electronic brake system.

If the electronic brake system is determined to be leaking, closing the inlet valve included in the first hydraulic circuit so that the flow rate is not discharged to the first hydraulic circuit; And confirming the leak judgment; It may further include.

In addition, the step of confirming the leak determination; recalculating the equivalent stiffness coefficient; And determining that the recalculated equivalent stiffness coefficient is less than a second threshold value greater than the first threshold value, as a leak of the second hydraulic circuit.

The method may further include: verifying the leak determination; when the recalculated equivalent stiffness coefficient is greater than the second threshold value, opening the inlet valve included in the first hydraulic circuit, and included in the second hydraulic circuit. Closing the inlet valve; And recalculating the equivalent stiffness coefficient, and determining that the recalculated equivalent stiffness coefficient is less than a second threshold value as the leak of the first hydraulic circuit.

The determining of the leak determination may further include determining that the electronic brake system is normal if the recalculated equivalent stiffness coefficient is greater than the second threshold value.

In embodiments of the present invention, the leak may be determined using a motor control sensor without using an additional pressure sensor.

Therefore, the reliability of the leak judgment in the electronic brake system can be improved.

1 is a hydraulic circuit diagram illustrating a non-braking state of an electronic brake system according to an exemplary embodiment of the present invention.
2 is a block diagram of an electronic brake system according to an exemplary embodiment.
3 is a detailed block diagram of an electronic brake system according to an exemplary embodiment.
4 is a flowchart illustrating a leak determination method according to an exemplary embodiment.
5 is a flowchart illustrating a method of determining a leak determining circuit when determining a leak according to an exemplary embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are presented to sufficiently convey the spirit of the present invention to those skilled in the art. The present invention is not limited to the embodiments presented herein but may be embodied in other forms. The drawings may omit illustrations of parts not related to the description in order to clarify the present invention, and may be exaggerated to some extent in order to facilitate understanding.

1 is a hydraulic circuit diagram showing a state during non-braking of an electronic brake system 1 according to an embodiment of the present invention.

Referring to FIG. 1, the electronic brake system 1 typically includes a master cylinder 20 for generating hydraulic pressure, a reservoir 30 coupled to an upper portion of the master cylinder 20 to store oil, and a brake pedal ( An input rod 12 for pressing the master cylinder 20 according to the stepping force of 10), a wheel cylinder 40 for braking the wheels RR, RL, FR, and FL by transmitting hydraulic pressure, and a brake pedal A pedal displacement sensor 11 for detecting a displacement of the 10 and a simulation device 50 for providing a reaction force according to the stepping force of the brake pedal 10 are provided.

The master cylinder 20 may be configured to have at least one chamber to generate hydraulic pressure. For example, the master cylinder 20 may include a first master chamber 20a and a second master chamber 20b.

Referring to FIG. 1, the simulation apparatus 50 includes a simulation chamber 51 provided to store oil flowing out of the first hydraulic port 24a of the master cylinder 20 and a reaction force piston provided in the simulation chamber 51. 52 and a pedal simulator having a reaction force spring 53 to elastically support it, and a simulator valve 54 connected to the rear end of the simulation chamber 51.

The reaction force piston 52 and the reaction force spring 53 are installed to have a range of displacement in the simulation chamber 51 by oil flowing into the simulation chamber 51.

Meanwhile, the reaction force spring 53 illustrated in the drawing is just one embodiment capable of providing an elastic force to the reaction force piston 52, and may include various embodiments capable of storing the elastic force by shape deformation. For example, it is made of a material such as rubber, or includes a variety of members that can store the elastic force by having a coil or plate shape.

The simulator valve 54 may be provided in a flow path connecting the rear end of the simulation chamber 51 and the reservoir 30. The front end of the simulation chamber 51 may be connected to the master cylinder 20, and the rear end of the simulation chamber 51 may be connected to the reservoir 30 through the simulator valve 54. Therefore, even when the reaction force piston 52 is returned, the oil of the reservoir 30 is introduced through the simulator valve 54 so that the entire interior of the simulation chamber 51 may be filled with oil.

Meanwhile, several reservoirs 30 are shown in the figure, and each reservoir 30 uses the same reference numeral. However, these reservoirs may be provided with the same parts or different parts. For example, the reservoir 30 connected to the simulation device 50 may be the same as the reservoir 30 connected to the master cylinder 20, or may store oil separately from the reservoir 30 connected to the master cylinder 20. It can be a repository.

On the other hand, the simulator valve 54 may be configured as a normally closed solenoid valve to maintain the normally closed state. The simulator valve 54 may be opened when the driver applies the pedal force to the brake pedal 10 to transfer oil in the simulation chamber 51 to the reservoir 30.

In addition, a simulator check valve 55 may be installed between the pedal simulator and the reservoir 30 so as to be connected in parallel with the simulator valve 54. The simulator check valve 55 allows the oil of the reservoir 30 to flow into the simulation chamber 51, but the oil of the simulation chamber 51 flows to the reservoir 30 through a flow path in which the check valve 55 is installed. Can be blocked. Since the oil can be supplied into the simulation chamber 51 through the simulator check valve 55 when the pedal pedal 10 releases the pedal effort, a quick return of the pedal simulator pressure can be ensured.

The operation of the pedal simulation apparatus 50 will be described. The simulation chamber 51 which pushes the reaction force piston 52 while compressing the reaction force spring 53 by the reaction force piston 52 of the pedal simulator when the driver provides the pedal force to the brake pedal 10. The oil in it is delivered to the reservoir 30 through the simulator valve 54, and in this process the driver is provided with a feeling of pedaling. And when the driver releases the pedal force on the brake pedal 10, the reaction force spring 53 pushes the reaction force piston 52, and the reaction force piston 52 returns to its original state, and the oil of the reservoir 30 returns to the simulator valve ( The oil may be filled in the simulation chamber 51 while flowing into the simulation chamber 51 through the flow path where the 54 is installed and the flow path where the check valve 55 is installed.

As such, since the interior of the simulation chamber 51 is always filled with oil, the friction of the reaction force piston 52 is minimized when the simulation apparatus 50 is operated, thereby improving durability of the simulation apparatus 50 as well as foreign matters from the outside. The inflow of can be blocked.

The electronic brake system 1 according to an embodiment of the present invention is a hydraulic pressure supply device 100 which is mechanically operated by receiving a driver's braking will as an electrical signal from a pedal displacement sensor 11 for detecting a displacement of the brake pedal 10. ) And a hydraulic control unit comprising first and second hydraulic circuits 201 and 202 for controlling the flow of hydraulic pressure delivered to the wheel cylinder 40 provided on the two wheels RR, RL, FR, and FL, respectively. A first cut valve 261 provided at a first backup flow path 251 connecting the first hydraulic port 24a and the first hydraulic circuit 201 to the hydraulic pressure; A second cut valve 262 provided in the second backup passage 252 connecting the hydraulic port 24b and the second hydraulic circuit 202 to control the flow of the hydraulic pressure, and the hydraulic pressure based on the hydraulic pressure information and the pedal displacement information. To control supply 100 and valves 54, 60, 221a, 221b, 221c, 221d, 222a, 222b, 222c, 222d, 233, 235, 236, 243 It may comprise a control unit (ECU, not shown).

The hydraulic pressure supply device 100 includes a hydraulic pressure providing unit 110 providing oil pressure transmitted to the wheel cylinder 40, a motor 120 generating a rotational force by an electrical signal of the pedal displacement sensor 11, and a motor. It may include a power conversion unit 130 for converting the rotational movement of the 120 to a linear movement to transmit to the hydraulic pressure providing unit (110). Alternatively, the hydraulic pressure providing unit 110 may operate by the pressure provided by the high pressure accumulator, not the driving force supplied from the motor 120.

Next, the flow paths 211, 212, 213, 214, 215, 216, 217 and the belts 231, 232, 233, 234, which are connected to the first pressure chamber 112 and the second pressure chamber 113, are provided. 235, 236, 241, 242 and 243 will be described.

The second hydraulic passage 212 may communicate with the first hydraulic circuit 201, and the third hydraulic passage 213 may communicate with the second hydraulic circuit 202. Therefore, the hydraulic pressure may be transmitted to the first hydraulic circuit 201 and the second hydraulic circuit 202 by the advancement of the hydraulic piston 114.

In addition, the electronic brake system 1 according to the embodiment of the present invention is provided in the second and third hydraulic flow paths 212 and 213, respectively, to control the flow of oil, the first control valve 231 and the second control valve ( 232).

The first and second control valves 231 and 232 allow only oil flow in the direction from the first pressure chamber 112 to the first or second hydraulic circuits 201 and 202, and oil flow in the opposite direction. May be provided as a check valve for blocking. That is, the first or second control valves 231 and 232 allow the hydraulic pressure of the first pressure chamber 112 to be transmitted to the first or second hydraulic circuits 201 and 202 while the first or second hydraulic valves are used. It is possible to prevent the hydraulic pressure of the circuits 201 and 202 from leaking into the first pressure chamber 112 through the second or third hydraulic passages 212 and 213.

On the other hand, the fourth hydraulic passage 213 may be branched into the fifth hydraulic passage 215 and the sixth hydraulic passage 216 on the way and may communicate with both the first hydraulic circuit 201 and the second hydraulic circuit 202. . For example, the fifth hydraulic passage 215 branched from the fourth hydraulic passage 214 communicates with the first hydraulic circuit 201, and the sixth hydraulic passage 216 branched from the fourth hydraulic passage 214 is It may be in communication with the second hydraulic circuit 202. Therefore, the hydraulic pressure may be transmitted to both the first hydraulic circuit 201 and the second hydraulic circuit 202 by reversing the hydraulic piston 114.

In addition, the electronic brake system 1 according to the embodiment of the present invention is provided in the third hydraulic valve 233 and the sixth hydraulic passage 216 provided in the fifth hydraulic passage 215 to control the flow of oil. It may include a fourth control valve 234 for controlling the flow.

The third control valve 233 may be provided as a bidirectional control valve for controlling oil flow between the second pressure chamber 113 and the first hydraulic circuit 201. The third control valve 233 is normally closed and may be provided as a normal closed solenoid valve that operates to open the valve when the open control signal is received from the electronic control unit.

In addition, the fourth control valve 234 may be provided as a check valve that allows only oil flow in a direction from the second pressure chamber 113 to the second hydraulic circuit 202 and blocks oil flow in the opposite direction. . That is, the fourth control valve 234 may prevent the hydraulic pressure of the second hydraulic circuit 202 from leaking into the second pressure chamber 113 through the sixth hydraulic channel 216 and the fourth hydraulic channel 214. Can be.

In addition, the electronic brake system 1 according to the embodiment of the present invention is provided in the seventh hydraulic passage 217 connecting the second hydraulic passage 212 and the third hydraulic passage 213 to control the flow of oil. And a fifth control valve 235 and a sixth control valve 236 provided in the eighth hydraulic passage 218 connecting the second hydraulic passage 212 and the seventh hydraulic passage 217 to control the flow of oil. can do. In addition, the fifth control valve 235 and the sixth control valve 236 are normally closed solenoid valves that operate to open the valve upon receiving an open signal from the electronic control unit 2000. Can be prepared.

When the abnormality occurs in the first control valve 231 or the second control valve 232, the fifth control valve 235 and the sixth control valve 236 are operated to open to operate the first control chamber 112. The hydraulic pressure may be transmitted to both the first hydraulic circuit 201 and the second hydraulic circuit 202.

The fifth control valve 235 and the sixth control valve 236 may operate to open when the hydraulic pressure of the wheel cylinder 40 is removed and sent to the first pressure chamber 112. This is because the first control valve 231 and the second control valve 232 provided in the second hydraulic passage 212 and the third hydraulic passage 213 are provided as check valves that allow only one-way oil flow.

In addition, the electronic brake system 1 according to an embodiment of the present invention is provided in the first and second dump passages 116 and 117, respectively, to control the flow of oil, the first dump valve 241 and the second dump valve ( 242 may be further included. The dump valves 241 and 242 may be check valves that open only the direction from the reservoir 30 to the first or second pressure chambers 112 and 113 and close the opposite directions. That is, the first dump valve 241 allows oil to flow from the reservoir 30 to the first pressure chamber 112, but blocks the flow of oil from the first pressure chamber 112 to the reservoir 30. It may be a check valve, the second dump valve 242 allows the oil to flow from the reservoir 30 to the second pressure chamber 113, the oil from the second pressure chamber 113 to the reservoir 30 Flowing may be a check valve to shut off.

In addition, the second dump flow path 117 may include a bypass flow path, and the bypass flow path may include a third dump valve 243 for controlling oil flow between the second pressure chamber 113 and the reservoir 30. Can be installed.

The third dump valve 243 may be provided as a solenoid valve for controlling bidirectional flow, and is normally open, but is normally open and operates to close the valve upon receiving a closing signal from the electronic control unit. type) solenoid valve.

The hydraulic pressure providing unit 110 of the electronic brake system 1 according to the embodiment of the present invention may operate in a double-acting manner. That is, the hydraulic pressure generated in the first pressure chamber 112 while the hydraulic piston 114 is advanced is transmitted to the first hydraulic circuit 201 through the first hydraulic passage 211 and the second hydraulic passage 212 to the right. The wheel cylinder 40 installed on the front wheel FR and the left rear wheel LR may be actuated and transferred to the second hydraulic circuit 202 through the first hydraulic channel 211 and the third hydraulic channel 213. The wheel cylinder 40 is installed on the right rear wheel RR and the left front wheel FL.

Similarly, the hydraulic pressure generated in the second pressure chamber 113 while the hydraulic piston 114 is retracted is transmitted to the first hydraulic circuit 201 through the fourth hydraulic channel 214 and the fifth hydraulic channel 215 to the right. The wheel cylinder 40 installed on the front wheel FR and the left rear wheel LR can be actuated and transferred to the second hydraulic circuit 202 through the fourth hydraulic channel 214 and the sixth hydraulic channel 216. The wheel cylinder 40 is installed on the right rear wheel RR and the left front wheel FL.

In addition, the negative pressure generated in the first pressure chamber 112 while the hydraulic piston 114 is reversed sucks oil from the wheel cylinders 40 installed at the right front wheel FR and the left rear wheel LR, and thus the first hydraulic circuit. The wheel 201, the second hydraulic passage 212, and the first hydraulic passage 211 may be transferred to the first pressure chamber 112 and are provided on the right rear wheel RR and the left front wheel FL. The oil of the cylinder 40 may be sucked and transferred to the first pressure chamber 112 through the second hydraulic circuit 202, the third hydraulic channel 213, and the first hydraulic channel 211.

Next, the motor 120 and the power converter 130 of the hydraulic pressure supply device 100 will be described.

The motor 120 is a device for generating a rotational force by the signal output from the electronic control unit 2000, and may generate the rotational force in the forward or reverse direction. Rotational angular velocity and rotational angle of the motor 120 can be precisely controlled. Since the motor 120 is a well-known technique already known, a detailed description thereof will be omitted.

On the other hand, the electronic control unit including the motor 120, the valves 54, 60, 221a, 221b, 221c, 221d, 222a, 222b, 222c, 222d, which are provided in the electronic brake system 1 of the present invention to be described later 233, 235, 236, and 243. An operation of controlling the plurality of valves according to the displacement of the brake pedal 10 will be described later.

The driving force of the motor 120 generates the displacement of the hydraulic piston 114 through the power converter 130, and the hydraulic pressure generated while the hydraulic piston 114 slides in the pressure chamber is the first and second hydraulic flow paths. It is transmitted to the wheel cylinder 40 installed in each wheel RR, RL, FR, FL via 211, 212.

The power converter 130 is a device for converting rotational force into a linear motion, for example, may be composed of a worm shaft 131, a worm wheel 132 and a drive shaft 133.

The worm shaft 131 may be integrally formed with the rotation shaft of the motor 120, and a worm is formed on an outer circumferential surface thereof so as to engage with the worm wheel 132 to rotate the worm wheel 132. The worm wheel 132 is connected to engage with the drive shaft 133 to move the drive shaft 133 in a straight line, the drive shaft 133 is connected to the hydraulic piston 114 to slide the hydraulic piston 114 in the cylinder block 111. Move it.

To describe the above operations again, a signal sensed by the pedal displacement sensor 11 while the displacement occurs in the brake pedal 10 is transmitted to the electronic control unit 2000, the electronic control unit 2000 is a motor 120 Drive in one direction to rotate the worm shaft 131 in one direction. The rotational force of the worm shaft 131 is transmitted to the drive shaft 133 via the worm wheel 132, and the hydraulic piston 114 connected to the drive shaft 133 moves forward to generate hydraulic pressure in the first pressure chamber 112.

On the contrary, when the stepping force is removed from the brake pedal 10, the electronic control unit 2000 drives the motor 120 in the opposite direction so that the worm shaft 131 rotates in the opposite direction. Accordingly, the worm wheel 132 also rotates in the opposite direction and generates negative pressure in the first pressure chamber 112 while the hydraulic piston 114 connected to the drive shaft 133 returns (reverses moving).

On the other hand, the hydraulic and negative pressure can be generated in the opposite direction. That is, while the displacement occurs in the brake pedal 10, the signal sensed by the pedal displacement sensor 11 is transmitted to the electronic control unit (ECU, not shown), and the electronic control unit drives the motor 120 in the opposite direction. To rotate the worm shaft 131 in the opposite direction. The rotational force of the worm shaft 131 is transmitted to the drive shaft 133 via the worm wheel 132, and the hydraulic piston 114 connected to the drive shaft 133 moves backward to generate hydraulic pressure in the second pressure chamber 113.

On the contrary, when the stepping force is removed from the brake pedal 10, the electronic control unit drives the motor 120 in one direction so that the worm shaft 131 rotates in one direction. Accordingly, the worm wheel 132 also rotates in the opposite direction and generates negative pressure in the second pressure chamber 113 while the hydraulic piston 114 connected to the drive shaft 133 is returned (moving forward).

As such, the hydraulic pressure supply device 100 serves to transfer the hydraulic pressure to the wheel cylinder 40 or to suck the hydraulic pressure to the reservoir 30 according to the rotational direction of the rotational force generated from the motor 120.

Meanwhile, when the motor 120 rotates in one direction, hydraulic pressure may be generated in the first pressure chamber 112 or negative pressure may be generated in the second pressure chamber 113. Whether or not to release the braking can be determined by controlling the valves 54, 60, 221a, 221b, 221c, 221d, 222a, 222b, 222c, 222d, 233, 235, 236, 243. This will be described in detail later.

Although not shown in the drawings, the power converter 130 may be configured as a ball screw nut assembly. For example, a screw formed integrally with the rotation shaft of the motor 120 or connected to rotate together with the rotation shaft of the motor 120, and a ball nut which is screwed with the screw in a limited rotation state and linearly moves according to the rotation of the screw. Can be. The hydraulic piston 114 is connected to the ball nut of the power converter 130 to pressurize the pressure chamber by the linear motion of the ball nut. The structure of such a ball screw nut assembly is a well-known technique that is already known as a device for converting rotational motion into linear motion, and thus a detailed description thereof will be omitted.

And the power conversion unit 130 according to an embodiment of the present invention should be understood as being capable of employing any structure if the rotational motion in addition to the structure of the ball screw nut assembly can be converted to linear motion.

In addition, the electronic brake system 1 according to the embodiment of the present invention is capable of supplying oil discharged from the master cylinder 20 directly to the wheel cylinder 40 during abnormal operation (fallback mode). The first and second backup channels 251 and 252 may be further included.

The first backup passage 251 may be provided with a first cut valve 261 for controlling the flow of oil, and the second backup passage 252 may be provided with a second cut valve 262 for controlling the flow of oil. have. In addition, the first backup passage 251 connects the first hydraulic port 24a and the first hydraulic circuit 201, and the second backup passage 252 connects the second hydraulic port 24b and the second hydraulic circuit ( 202 may be connected.

The first and second cut valves 261 and 262 may be provided as normal open type solenoid valves that are open in a normal state and operate to close the valve when the closing signal is received from the electronic control unit. have.

Next, with reference to Figure 1 will be described with respect to the hydraulic control unit 200 according to an embodiment of the present invention.

The hydraulic control unit 200 may be configured of a first hydraulic circuit 201 and a second hydraulic circuit 202 which receive hydraulic pressure to control two wheels, respectively. For example, the first hydraulic circuit 201 may control the right front wheel FR and the left rear wheel RL, and the second hydraulic circuit 202 may control the left front wheel FL and the right rear wheel RR. . Each wheel FR, FL, RR, and RL has wheel cylinders 40 installed therein to be supplied with hydraulic pressure to perform braking.

The first hydraulic circuit 201 is connected to the first hydraulic passage 211 and the second hydraulic passage 212 to receive the hydraulic pressure from the hydraulic pressure supply device 100, and the second hydraulic passage 212 is the right front wheel FR And two flow paths connected to the left rear wheel RL. Similarly, the second hydraulic circuit 202 is connected to the first hydraulic passage 211 and the third hydraulic passage 213 to receive the hydraulic pressure from the hydraulic pressure supply device 100, and the third hydraulic passage 213 is the left front wheel. It branches into two flow paths connected to FL and the right rear wheel RR.

The hydraulic circuits 201 and 202 may include a plurality of inlet valves 221 (221a, 221b, 221c, and 221d) to control the flow of the hydraulic pressure. For example, the first hydraulic circuit 201 may be provided with two inlet valves 221a and 221b connected to the first hydraulic flow path 211 to control the hydraulic pressure transmitted to the two wheel cylinders 40, respectively. . In addition, the second hydraulic circuit 202 may be provided with two inlet valves 221c and 221d respectively connected to the second hydraulic flow path 212 to control the hydraulic pressure transmitted to the wheel cylinder 40.

The inlet valve 221 is disposed upstream of the wheel cylinder 40 and is open in a normal state, and operates to close the valve upon receiving the closing signal from the electronic control unit 2000. It can be provided with a solenoid valve of.

In addition, the hydraulic circuits 201 and 202 include check valves 223a, 223b, 223c, and 223d provided in a bypass flow path connecting the front and rear of the respective inlet valves 221a, 221b, 221c, and 221d. Can be. The check valves 223a, 223b, 223c, and 223d allow only the flow of oil from the wheel cylinder 40 toward the hydraulic pressure providing unit 110, and the oil from the hydraulic pressure providing unit 110 toward the wheel cylinder 40. The flow of can be arranged to limit. The check valves 223a, 223b, 223c, and 223d can quickly release the braking pressure of the wheel cylinder 40, and the wheel cylinders when the inlet valves 221a, 221b, 221c, and 221d do not operate normally. The hydraulic pressure of 40 may be introduced into the hydraulic pressure providing unit 110.

In addition, the hydraulic circuits 201 and 202 may further include a plurality of outlet valves 222: 222a, 222b, 222c, and 222d connected to the reservoir 30 to improve performance when braking is released. The outlet valves 222 are connected to the wheel cylinders 40, respectively, to control the hydraulic pressure from the wheels RR, RL, FR, and FL. That is, the outlet valve 222 senses the braking pressure of each wheel (RR, RL, FR, FL) to selectively open when the decompression braking is required to control the pressure.

The outlet valve 222 is normally closed and may be provided as a normal closed solenoid valve that operates to open the valve upon receiving an open signal from the electronic control unit.

In addition, the hydraulic control unit 200 may be connected to the backup passage (251, 252). For example, the first hydraulic circuit 201 is connected to the first backup passage 251 to receive hydraulic pressure from the master cylinder 20, and the second hydraulic circuit 202 is connected to the second backup passage 252. The hydraulic pressure may be provided from the master cylinder 20.

In this case, the first backup passage 251 may join the first hydraulic circuit 201 upstream of the first and second inlet valves 221a and 221b. Similarly, the second backup passage 252 may join the second hydraulic circuit 202 upstream of the third and fourth inlet valves 221c and 221d. Therefore, when the first and second cut valves 261 and 262 are closed, the hydraulic pressure provided from the hydraulic pressure supply device 100 may be supplied to the wheel cylinder 40 through the first and second hydraulic circuits 201 and 202. When the first and second cut valves 261 and 262 are opened, the hydraulic pressure provided from the master cylinder 20 may be supplied to the wheel cylinder 40 through the first and second backup passages 251 and 252. Can be. At this time, the plurality of inlet valves (221a, 221b, 221c, 221d) is an open state, it is not necessary to switch the operating state.

On the other hand, the reference numeral "PS11", which is not described, is a first hydraulic oil pressure sensor for detecting the hydraulic pressure of the first hydraulic circuit 201, and "PS12" is a second hydraulic oil for sensing the hydraulic pressure of the second hydraulic circuit 202. Low pressure sensor, "PS2" is a backup flow pressure sensor for measuring the oil pressure of the master cylinder (20). And "MPS" is a motor control sensor for controlling the rotation angle of the motor 120 or the current of the motor.

Hereinafter, the operation of the electronic brake system 1 according to the embodiment of the present invention will be described in detail.

The hydraulic pressure supply device 100 may use the low pressure mode and the high pressure mode separately. The low pressure mode and the high pressure mode may be changed by different operations of the hydraulic control unit 200. The hydraulic pressure supply device 100 may generate a high hydraulic pressure without increasing the output of the motor 120 by using the high pressure mode. Therefore, it is possible to ensure stable braking force while lowering the price and weight of the brake system.

In more detail, the hydraulic piston 114 generates hydraulic pressure in the first pressure chamber 112 while advancing. As the hydraulic piston 114 moves forward in the initial state, that is, as the stroke of the hydraulic piston 114 increases, the amount of oil transferred from the first pressure chamber 112 to the wheel cylinder 40 increases, so that the braking pressure is increased. To rise. However, since there is an effective stroke of the hydraulic piston 114, there is a maximum pressure due to the advancement of the hydraulic piston 114.

At this time, the maximum pressure in the low pressure mode is smaller than the maximum pressure in the high pressure mode. However, the high pressure mode has a small pressure increase rate per stroke of the hydraulic piston 114 as compared with the low pressure mode. This is because all of the oil pushed out of the first pressure chamber 112 does not flow into the wheel cylinder 40, but part of the oil flows into the second pressure chamber 113. This will be described in detail with reference to FIG. 5.

Therefore, in the early stage of braking where braking responsiveness is important, a low pressure mode having a large pressure increase rate per stroke may be used, and a high pressure mode having a large maximum pressure may be used in a late braking where the maximum braking force is important.

When braking by the driver is started, the amount of braking required by the driver may be sensed through information such as the pressure of the brake pedal 10 that the driver presses through the pedal displacement sensor 11. The electronic control unit 2000 receives the electrical signal output from the pedal displacement sensor 11 to drive the motor 120.

In addition, the electronic control unit 2000 has the magnitude of the regenerative braking amount through the backup flow path pressure sensor PS2 provided on the outlet side of the master cylinder 20 and the hydraulic flow pressure pressure sensor PS1 provided on the second hydraulic circuit 202. In response to the input, the magnitude of the friction braking amount may be calculated by determining the magnitude of the friction braking amount according to the difference between the required braking amount and the regenerative braking amount of the driver.

Next, FIG. 2 is an internal block diagram of the electronic brake system 1 according to an embodiment of the present invention, and the electronic control unit 2000 and the electronic brake system 1 which collectively control the electronic brake system 1 are illustrated. FIG. 3 is a block diagram showing a state connected to the brake device 1000 included in FIG. As illustrated in FIG. 2, the brake device 1000 included in the electronic brake system 1 is not shown in FIG. 1, but may be configured in various configurations included in the brake device according to a control signal of the electronic control unit 2000. Operation may be possible.

Specifically, referring to FIG. 3, the electronic control unit 2000 of the electronic brake system 1 according to an embodiment of the present invention may include an input unit 102, a determination unit 104, a calculation unit 106, and a control unit ( 108).

The input unit 102 receives an operation signal and a control signal of the brake device 1000.

For example, the input unit 102 receives a motor control sensor value from the motor control sensor MPS of the brake device 1000. The motor control sensor value calculated by the motor control sensor MPS includes a rotation angle of the motor 120 or a current value of the motor.

In addition, the input unit 102 may receive, in real time, the hydraulic pressure of each area of the circuit of the brake device 1000 from the pressure sensor PS of the brake device 1000. For example, the input unit 102 receives the hydraulic pressure of the first hydraulic circuit 201 sensed by the PS11 pressure sensor shown in FIG. 1, and inputs the hydraulic pressure of the second hydraulic circuit 202 sensed by the PS12 pressure sensor. The oil pressure of the master cylinder 20 sensed by the PS2 pressure sensor may be input.

In addition, the input unit 102 may receive the open state of the various valves and the piston stroke distance information, etc. included in the brake device 1000, and various controls only from the configuration shown in the brake device 1000 of FIG. 3. It is not limited to receiving a signal or an operation signal.

Next, the calculator 106 estimates the equivalent stiffness coefficient from the input rotation angle of the motor 120 and the current value of the motor. Hereinafter, the method by which the calculating part 106 estimates the equivalent stiffness coefficient K of the electronic brake system 1 is demonstrated.

In general, the motor torque of the electronic brake system can be represented by the product of the motor rotation angle and the equivalent stiffness coefficient of the system, as shown in [Equation 1].

[Equation 1]

는 모터 토크를,

는 모터 회전각을 의미하며, k는 전자식 브레이크 시스템의 등가 강성계수를 의미한다. only,

Motor torque,

Is the motor rotation angle and k is the equivalent stiffness coefficient of the electronic brake system.

)를 모터 회전각(

)으로 나눈 값으로 표현될 수 있다. Therefore, the equivalent stiffness coefficient K of the system is the motor torque (

) Motor rotation angle (

It can be expressed by dividing by).

)는 모터 제어 센서(MPS)로부터 입력부(102)가 입력 받은 모터의 전류값과 비례 관계이다. In this case, the motor rotation angle may be input by the input unit 102 from the motor control sensor MPS. In addition, the motor torque (

) Is proportional to the current value of the motor inputted by the input unit 102 from the motor control sensor MPS.

Therefore, the equivalent stiffness coefficient K of the electronic brake system 1 can be modeled as follows.

[Equation 2]

는 모터 회전각을, i_q는 모터(120)의 전류값을 의미한다. Where k is the equivalent stiffness factor of the electronic brake system and C _k is the motor current constant,

Denotes a motor rotation angle, and i _q denotes a current value of the motor 120.

Accordingly, the calculation unit 106 may calculate the equivalent stiffness coefficient in real time from the current value and the rotation angle of the motor obtained from the input unit 102, and the determination unit 104 may determine the electronic brake based on the calculated equivalent stiffness coefficient. It is possible to determine whether leakage has occurred in the circuits constituting the system 1.

As an example, if the stiffness coefficient calculated by the calculator 106 is smaller than a preset threshold value (first threshold value), the determination unit 104 determines that a leak has occurred.

Therefore, when the control unit 108 receives the leak generation signal from the determination unit 104, the control unit 108 controls the inlet valve to determine in which circuit the leak occurs in the first hydraulic circuit 201 or the second hydraulic circuit 202. do.

First, the braking force is calculated in a state where all of the inlet valves 221a and 221b included in the first hydraulic circuit 201 are closed. At this time, since all of the inlet valves 221a and 221b included in the first hydraulic circuit 201 are closed, the braking force is generated only by the second hydraulic circuit 202.

Only when the second hydraulic circuit 202 generates the braking force has an equivalent stiffness coefficient higher than the system equivalent stiffness coefficient at the time of generating the braking force by using both the first hydraulic circuit 201 and the second hydraulic circuit 202. Therefore, the equivalent stiffness coefficient calculated when the braking force is generated only by the second hydraulic circuit 202 is compared with a second threshold value larger than the first threshold value.

If the equivalent stiffness coefficient calculated when the braking force is generated only by the second hydraulic circuit 202 is greater than the second threshold value, the determination unit 104 may determine that the second hydraulic circuit 202 operates normally. It may be determined that a leak has occurred in the first hydraulic circuit 201.

On the contrary, if the equivalent stiffness coefficient calculated when the braking force is generated only by the second hydraulic circuit 202 is smaller than the second threshold value, the controller 108 controls the inlet valves 221a and 221b included in the first hydraulic circuit 201. ) Is opened again, and the inlet valves 221c and 221d included in the second hydraulic circuit 202 are closed. Therefore, in this case, since all of the inlet valves 221c and 221d included in the second hydraulic circuit 202 are closed, the braking force is generated only by the first hydraulic circuit 201.

Only when the first hydraulic circuit 201 generates the braking force has an equivalent stiffness coefficient higher than the system equivalent stiffness coefficient at the time of generating the braking force by using both the first hydraulic circuit 201 and the second hydraulic circuit 202. Therefore, the equivalent stiffness coefficient calculated when the braking force is generated only by the first hydraulic circuit 201 is compared with a second threshold larger than the first threshold.

If the equivalent stiffness coefficient calculated when the braking force is generated only by the first hydraulic circuit 201 is greater than the second threshold value, the determination unit 104 may determine that the first hydraulic circuit 201 operates normally. It may be determined that a leak has occurred in the second hydraulic circuit 202.

On the contrary, if the equivalent stiffness coefficient calculated when the braking force is generated only by the second hydraulic circuit 202 is smaller than the second threshold value, the equivalent stiffness coefficient calculated when the braking force is generated by the first hydraulic circuit 202 alone is also the second threshold. Since it is smaller than the value, the determination unit 104 determines that the electronic brake system is normal.

In the above, the structure of the electronic brake system 1 which concerns on this invention was demonstrated.

Hereinafter, a control method of the electronic brake system 1 according to the present invention will be described. Specifically, FIG. 4 is a flowchart illustrating a leak determination method according to an exemplary embodiment, and FIG. 5 is a flowchart illustrating a method of determining a leak determination circuit according to an embodiment.

First, the electronic brake system 1 obtains a motor control sensor (MPS) motor current value (400). In addition, the electronic brake system 1 obtains a motor rotation angle from the motor control sensor MPS (410).

Next, the electronic brake system 1 calculates an equivalent stiffness coefficient of the system (420). Specifically, the system equivalent stiffness coefficient can be estimated from the obtained motor current value and the motor rotation angle.

That is, the estimated equivalent stiffness coefficient is compared with a preset threshold value (first threshold value). If the calculated equivalent stiffness coefficient is greater than the first threshold value (YES in 430), the electronic brake system 1 is internal to the system. It is determined that leakage does not occur, that is, normal (440).

However, when the calculated equivalent stiffness coefficient is smaller than the first threshold value (NO in 430), the electronic brake system 1 determines that leakage has occurred in the system, and additionally performs leakage determination (450).

Specifically, the leak determination method inside the system will be described with reference to FIG. 5.

First, when the control unit 108 in the electronic brake system 1 receives the leak generation signal from the determination unit 104, which circuit of the first hydraulic circuit 201 and the second hydraulic circuit 202 generates a leak. To determine the inlet valve (500).

Specifically, the controller 108 calculates the braking force in a state in which all of the inlet valves 221a and 221b included in the first hydraulic circuit 201 are closed. At this time, since all of the inlet valves 221a and 221b included in the first hydraulic circuit 201 are closed, the braking force is generated only by the second hydraulic circuit 202.

At this time, the calculation unit 106 in the electronic brake system 1 recalculates the equivalent stiffness coefficient (510). When the calculation unit 106 generates the braking force only by the second hydraulic circuit 202 when calculating the equivalent stiffness coefficient, the braking force is generated by using both the first hydraulic circuit 201 and the second hydraulic circuit 202. Since the equivalent stiffness coefficient higher than the system equivalent stiffness coefficient will be calculated, the equivalent stiffness coefficient calculated when the braking force is generated only by the second hydraulic circuit 202 is compared with a second threshold value larger than the first threshold value (520). .

If the equivalent stiffness coefficient calculated when generating the braking force using only the second hydraulic circuit 202 is greater than the second threshold value (YES in 520), the determination unit 104 determines that the second hydraulic circuit 202 operates normally. In operation 530, it may be determined that a leak occurs in the first hydraulic circuit 201.

Therefore, in order to minimize the leakage in the first hydraulic circuit 201, the control unit 108 generates the braking pressure only by the second hydraulic circuit 202 while maintaining the inlet valve closing control of the first hydraulic circuit.

On the contrary, if the equivalent stiffness coefficient calculated when generating the braking force using only the second hydraulic circuit 202 is smaller than the second threshold value (NO in 520), the controller 108 may include the inlet included in the first hydraulic circuit 201. The valves 221a and 221b are opened again (550) and the inlet valves 221c and 221d included in the second hydraulic circuit 202 are closed (560). Therefore, in this case, since all of the inlet valves 221c and 221d included in the second hydraulic circuit 202 are closed, the braking force is generated only by the first hydraulic circuit 201.

Similarly, the calculation unit 106 in the electronic brake system 1 recalculates the equivalent stiffness coefficient (570).

If the equivalent stiffness coefficient calculated when generating the braking force using only the first hydraulic circuit 201 is greater than the second threshold value (Yes of 580), the determination unit 104 determines that the first hydraulic circuit 201 operates normally. In operation 590, it may be determined that leakage occurs in the second hydraulic circuit 202. Therefore, in order to minimize the leakage in the second hydraulic circuit 202, the control unit 108 generates the braking pressure only by the first hydraulic circuit 201 while maintaining the inlet valve closing control of the second hydraulic circuit (600). ).

However, if the equivalent stiffness coefficient calculated when the braking force is generated only by the second hydraulic circuit 202 is smaller than the second threshold value (No of 580), the equivalent stiffness coefficient calculated when the braking force is generated only by the first hydraulic circuit 202 only. Since it is smaller than the second threshold of FIG. 2, the determination unit 104 determines that the electronic brake system is normal (610).

Although one embodiment of the disclosed invention has been illustrated and described above, the disclosed invention is not limited to the specific embodiments described above, and those skilled in the art without departing from the scope of the claims. Of course, various modifications can be made by the above, and these modifications can not be individually understood from the disclosed invention.

10: brake pedal 11: pedal displacement sensor
20: master cylinder 30: reservoir
40: wheel cylinder 50: simulation device
54: simulator valve 60: inspection valve
100: hydraulic pressure supply unit 110: hydraulic pressure supply unit
120: motor 130: power converter
200: hydraulic control unit 201: first hydraulic circuit
202: second hydraulic circuit 211: first hydraulic flow path
212: second hydraulic flow path 213: third hydraulic flow path
214: fourth hydraulic flow path 215: fifth hydraulic flow path
216: sixth hydraulic flow path 217: seventh hydraulic flow path
218: eighth hydraulic flow path 221: inlet valve
222: outlet valve 223: check valve
231: first control valve 232: second control valve
233: third control valve 234: fourth control valve
235: fifth control valve 236: sixth control valve
241: first dump valve 242: second dump valve
243: third dump valve 251: first backup flow path
252: second back-up flow path 261: first cut valve
262: second cut valve

Claims (10)

In the electronic brake system including a hydraulic pressure supply device for generating a hydraulic pressure using the rotational force of the motor operated by the electrical signal output from the pedal position sensor, and a motor control sensor for measuring the current and the rotation angle of the motor,
A controller that calculates an equivalent stiffness coefficient of the electronic brake system based on the measured current and rotation angle of the motor, and determines that the calculated equivalent stiffness coefficient is less than a first threshold value as a leak of the electronic brake system; Electronic brake system including. The method of claim 1,
A first hydraulic circuit for transferring the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel; And
A second hydraulic circuit configured to transfer the hydraulic pressure discharged from the hydraulic pressure supply device to a wheel cylinder provided on at least one wheel;
The first hydraulic circuit and the second hydraulic circuit, the electronic brake system including an inlet valve for each wheel to adjust the flow rate discharged from the hydraulic pressure supply device. The method of claim 2,
The control unit,
If it is determined that the electronic brake system is leaking, the inlet valve included in the first hydraulic circuit is closed so that the flow rate is not discharged to the first hydraulic circuit, the equivalent stiffness coefficient is recalculated, and the recalculated equivalent stiffness coefficient And if less than a second threshold value greater than a first threshold value, determine the leak in the second hydraulic circuit. The method of claim 3,
The control unit,
If the recalculated equivalent stiffness coefficient is greater than the second threshold value, the inlet valve included in the first hydraulic circuit is opened, the inlet valve included in the second hydraulic circuit is closed, and the equivalent stiffness coefficient is reset. The electronic brake system that calculates and determines that the recalculated equivalent stiffness coefficient is less than the second threshold value as the leak of the first hydraulic circuit. The method of claim 4, wherein
The control unit,
And if the recalculated equivalent stiffness coefficient is greater than the second threshold value, determine that the electronic brake system is normal. In the control method of the electronic brake system including a hydraulic pressure supply device for generating a hydraulic pressure by using the rotational force of the motor operated by the electrical signal output from the pedal position sensor, and a motor control sensor for measuring the current and the rotation angle of the motor. In
Calculating an equivalent stiffness coefficient of the electronic brake system based on the measured current and rotation angle of the motor;
And determining that the calculated equivalent stiffness coefficient is less than a first threshold value as a leak of the electronic brake system. The method of claim 6,
If it is determined that the electronic brake system is leaking, closing the inlet valve included in the first hydraulic circuit such that the flow rate is not discharged to the first hydraulic circuit; And
Confirming the leak judgment; The control method of the electronic brake system further comprising. The method of claim 7, wherein
Confirming the leak determination;
Recalculating the equivalent stiffness coefficient; And
If the recalculated equivalent stiffness coefficient is less than a second threshold value that is greater than the first threshold value, determining the leak of the second hydraulic circuit. The method of claim 8,
Confirming the leak determination;
Opening the inlet valve included in the first hydraulic circuit and closing the inlet valve included in the second hydraulic circuit if the recalculated equivalent stiffness coefficient is greater than the second threshold value; And
And recalculating the equivalent stiffness coefficient, and determining that the recalculated equivalent stiffness coefficient is less than a second threshold value as a leak of the first hydraulic circuit. The method of claim 9,
Confirming the leak determination;
And determining that the electronic brake system is normal if the recalculated equivalent stiffness coefficient is greater than the second threshold value.

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