Electromechanical braking system and control method for it

Abstract

Disclosed is an electromechanical braking system comprising: a first pedal sensor, a second pedal sensor, and a third pedal sensor configured to detect pedal force applied to the brake pedal and to generate a first brake signal, a second brake signal, and a third brake signal; a first EMB, a second EMB, a third EMB, and a fourth EMB, each installed in a plurality of wheels of the vehicle and configured to provide braking force to a plurality of wheels of the vehicle; a first brake controller connected to the first pedal sensor and configured to obtain a first target braking torque based on the first brake signal and to transmit the first target braking torque to the first, second, third, and fourth EMBs;and a second brake control unit connected to and configured with the first pedal sensor, the second pedal sensor, and the third pedal sensor to obtain a second target braking torque based on the first brake signal, the second brake signal, and the third brake signal, and to transmit the second target braking torque to the first, second, third, and fourth EMBs.

Description

Background1. Area

[0001] The disclosure relates to an electromechanical braking system applicable to an autonomous vehicle by ensuring minimal braking control even in a failure situation of some components, and a control method thereof. 2. Description of the state of the art

[0002] With the advancement of automotive technology, the development and requirements of autonomous driving technology are becoming more specific. Above all, one of the key issues in autonomous driving technology is ensuring safety. If a vehicle drives itself instead of humans, safety should be ensured while the vehicle is moving, and accordingly, safety standards for autonomous vehicles should be at very high levels.

[0003] In comparison, the performance of the braking system used in autonomous vehicles should not only be good but also be capable of performing brake control without any problems, even if a failure occurs in any of the components that make up the braking system. To this end, existing automobile manufacturers ensure safety by providing redundancy in the components of the electromechanical braking system used in autonomous vehicles.

[0004] However, providing redundancy to the electromechanical braking system causes disadvantages such as complexity, an increase in weight and high costs of added parts. Summary

[0005] It is an aspect of the disclosure to provide an electromechanical braking system capable of ensuring minimum braking performance even in a failure situation of some components in a braking system, and a control method therefor.

[0006] Additional aspects of the disclosure are set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure.

[0007] According to one aspect of the disclosure, an electromechanical brake system may include: a first pedal sensor, a second pedal sensor, and a third pedal sensor configured to detect a pedal force applied to a brake pedal and generate a first brake signal, a second brake signal, and a third brake signal; a first electromechanical brake (EMB), a second EMB, a third EMB, and a fourth EMB, each installed in a plurality of wheels of a vehicle and configured to apply a braking force to the plurality of wheels of the vehicle; a first brake controller connected to the first pedal sensor and configured to obtain a first target braking torque based on the first brake signal and transmit the first target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB;and a second brake controller connected to the first pedal sensor, the second pedal sensor, and the third pedal sensor, and configured to obtain a second target braking torque based on the first braking signal, the second braking signal, and the third braking signal, and to transmit the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB, wherein the second brake controller may be configured to detect a failure of at least one of the first pedal sensor, the second pedal sensor, or the third pedal sensor based on the first braking signal, the second braking signal, and the third braking signal.

[0008] Based on a failure of a brake controller of the first brake controller or the second brake controller, another non-failed brake controller may transmit the first target braking torque or the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB.

[0009] The first pedal sensor, the first brake controller, the first EMB, and the fourth EMB may be powered by a first battery of the vehicle. The second pedal sensor, the third pedal sensor, the second brake controller, the second EMB, and the third EMB may be powered by a second vehicle battery.

[0010] Based on a failure of the first battery, the second brake controller may obtain the second target braking torque based on the first braking signal, the second braking signal, and the third braking signal, and transmit the second target braking torque to the second EMB and the third EMB.

[0011] Based on a failure of the second battery, the second brake controller may obtain the first target braking torque based on the first braking signal and transmit the first target braking torque to the first EMB and the fourth EMB.

[0012] The first EMB, the second EMB, the third EMB, and the fourth EMB can detect failures of a plurality of wheel speed sensors each installed in the plurality of wheels of the vehicle.

[0013] The first EMB, the second EMB, the third EMB, and the fourth EMB may receive a wheel speed signal from the plurality of wheel speed sensors installed in the plurality of wheels of the vehicle, respectively, and transmit the wheel speed signal to the first brake controller and the second brake controller.

[0014] The first brake controller may obtain the first target braking torque based on the first braking signal and the wheel speed signal. The second brake controller may obtain the second target braking torque based on the first braking signal, the second braking signal, the third braking signal, and the wheel speed signal.

[0015] The first brake controller may be connected to an electronic control unit (ECU) in the vehicle through a communication network, and may perform at least one of the anti-lock braking system (ABS) control, the electronic stability control (ESC) control, and the traction control system (TCS) control.

[0016] The first brake controller and the second brake controller can be connected to a first local area network. Upon detection of a failure of the first pedal sensor, the second brake controller can obtain the second target braking torque based on the second brake signal and the third brake signal.

[0017] The second brake controller can transmit the second target braking torque to the first brake controller.

[0018] The second brake controller can transmit the second target braking torque to the first EMB, the second EMB, the third EMB and the fourth EMB.

[0019] The second brake controller may transmit a failure signal from the second pedal sensor to the first brake controller. The first brake controller does not need to receive the first target braking torque based on receipt of the failure signal.

[0020] The first brake controller may transmit the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB based on receiving the second target braking torque.

[0021] Upon receiving both the first target braking torque and the second target braking torque, the first EMB, the second EMB, the third EMB, and the fourth EMB may perform a brake control based on the first target braking torque. According to one aspect of the disclosure, a method of controlling an electromechanical brake system of a vehicle includes: a first pedal sensor, a second pedal sensor, a third pedal sensor, a first brake controller, a second brake controller, a first electromechanical brake (EMB), a second EMB, a third EMB, and a fourth EMB, wherein the first pedal sensor, the first brake controller, the first EMB, and the fourth EMB are powered by a first battery of the vehicle, and the second pedal sensor, the third pedal sensor, the second brake controller, the second EMB, and the third EMB are powered by a second battery of the vehicle.and the third pedal sensor, a pedal force applied to a brake pedal; at the first pedal sensor, generating at the second pedal sensor and the third pedal sensor a first brake signal, a second brake signal, and a third brake signal; at the first brake controller connected to the first pedal sensor, obtaining a first target braking torque based on the first brake signal; at the first brake controller, transmitting the first target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB; at the second brake controller connected to the first pedal sensor, the second pedal sensor, and the third pedal sensor, obtaining a second target braking torque based on the first brake signal, the second brake signal, and the third brake signal; at the second brake controller, transmitting the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB; at the first EMB, the second EMB,the third EMB and the fourth EMB, performing a brake control based on the first target braking torque upon receiving both the first target braking torque and the second target braking torque; detecting a failure of at least the first battery, the second battery, the first pedal sensor, the second pedal sensor, the third pedal sensor, the first brake controller, or the second brake controller; and performing a brake control based on the detected failure at any one of the first brake controller and the second brake controller.

[0022] Performing the brake control based on the detected failure may include, at the second brake controller, obtaining the second target braking torque based on the first braking signal, the second braking signal, and the third braking signal; and, at the second brake controller, transmitting the second target braking torque to the second EMB and the third EMB.

[0023] Performing the brake control based on the detected error may include the first brake controller obtaining the first target braking torque based on the first brake signal; and the first brake controller supplying the first target braking torque to the first EMB and the fourth EMB.

[0024] Performing the brake control obtaining may include, at the second brake controller, transmitting a failure signal of the first pedal sensor to the first brake controller; at the second brake controller, obtaining the second target braking torque based on the second braking signal and the third braking signal; and, at the second brake controller, transmitting the second target braking torque to the first brake controller or transmitting the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB.

[0025] The method may further include, at the first brake controller, transmitting, upon receiving the second target braking torque, the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB. Short description of the drawings

[0026] These and / or other aspects of the disclosure will be apparent and more easily understood from the following description of the embodiments when considered in conjunction with the accompanying drawings, in which: Fig. 1 schematically shows a configuration of an electromechanical brake system according to an embodiment; Fig. 2 is a block diagram showing a portion of an electromechanical braking system according to one embodiment; Fig. 3 shows a state in which a second battery in the electromechanical brake system of Fig. 1 has failed; Fig. 4 shows a state in which a first battery in the electromechanical brake system of Fig. 1 has failed; Fig. 5 shows a state in which a first electromechanical brake in the electromechanical brake system of Fig. 1 has failed; Fig. 6 shows a state in which a second brake control in the electromechanical brake system of Fig. 1 has failed; Fig. 7 shows a state in which a first pedal sensor in the electromechanical brake system of Fig. 1 has failed; Fig. 8 is a flowchart illustrating a method of controlling an electromechanical braking system according to one embodiment, and Fig. 9 is a flowchart illustrating a method of controlling an electromechanical braking system according to one embodiment. Detailed description

[0027] The following detailed description is provided to assist the reader in obtaining a thorough understanding of the methods, devices, and / or systems described herein. Accordingly, various changes, modifications, and equivalents are suggested to those skilled in the art. The sequence of described method steps is an example; however, the order of steps and / or the steps themselves are not limited to what is set forth herein and may be varied as is known in the art, with the exception of steps that necessarily occur in a particular order. In addition, corresponding descriptions of well-known functions and structures may be omitted for clarity and conciseness.

[0028] Furthermore, exemplary embodiments are described in more detail below with reference to the accompanying drawings. However, the exemplary embodiments may be embodied in many different forms and should not be construed as limited to the embodiments shown herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the exemplary embodiments to those skilled in the art. Like reference numerals indicate like elements throughout.

[0029] It is understood that while the terms "first," "second," etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. As used herein, the term "and / or" includes any combination of one or more of the related listed elements.

[0030] It is assumed that when an element is described as "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intervening elements. In contrast, when an element is described as "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms "a," "an," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0032] The expression “at least one of a, b and c” should be understood to include only a, only b, only c, both a and b, both b and c, or all of a, b and c.

[0033] Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

[0034] Fig. 1 schematically shows a configuration of an electromechanical brake system 1 according to an embodiment, and Fig. 2 is a block diagram showing a part of the electromechanical brake system 1 according to an embodiment.

[0035] With reference to the Fig. 1 and Fig. 2, the electromechanical brake system 1 may include a brake pedal unit 10, a first electro-mechanical brake (EMB) 21, a second EMB 22, a third EMB 23, a fourth EMB 24, a first wheel speed sensor 31, a second wheel speed sensor 32, a third wheel speed sensor 33, a fourth wheel speed sensor 34, a first battery 40, a second battery 50, a communication network 60, a first local area network 70, a second local area network 80, a third local area network 90, and a first brake control device 110.

[0036] The brake pedal unit 10 may include a first pedal sensor 11, a second pedal sensor 12, a third pedal sensor 13 and a second brake control device 120.

[0037] The first pedal sensor 11, the second pedal sensor 12, and the third pedal sensor 13 can detect a pedal force applied to a brake pedal to generate a first brake signal, a second brake signal, and a third brake signal. Each of the first pedal sensor 11, the second pedal sensor 12, and the third pedal sensor 13 can be a pedal travel sensor (PTS). The PTS can detect information about how far a driver has pressed the brake pedal, i.e., a pedal force, and can generate a brake signal corresponding to the pedal force.

[0038] The second brake control device 120 may form the brake pedal unit 10 together with the first pedal sensor 11, the second pedal sensor 12, and the third pedal sensor 13. The second brake control device 120 may obtain a second target braking torque based on a first braking signal, a second braking signal, and a third braking signal generated by the first pedal sensor 11, the second pedal sensor 12, and the third pedal sensor 13. Specifically, the second brake control device 120 may obtain a second target braking torque based on the first braking signal, the second braking signal, the third braking signal, and wheel speed signals received from the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24. The second brake control device 120 may transmit the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0039] Furthermore, the second brake control device 120 can detect a failure of at least one of the first pedal sensor 11, the second pedal sensor 12, or the third pedal sensor 13 based on a first brake signal, a second brake signal, and a third brake signal. Detecting a failure of at least one of the first pedal sensor 11, the second pedal sensor 12, or the third pedal sensor 13 can be performed by comparing the first brake signal, the second brake signal, and the third brake signal with each other.

[0040] Thus, the second brake control device 120 may form the brake pedal unit 10 together with the first pedal sensor 11, the second pedal sensor 12, and the third pedal sensor 13, and detect a failure of the first pedal sensor 11, the second pedal sensor 12, or the third pedal sensor 13, or obtain a second target braking torque and transmit the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0041] The first pedal sensor 11, the second pedal sensor 12 and the third pedal sensor 13 can be connected to the second brake control device 120 via a cable.

[0042] In addition, the first pedal sensor 11 can be connected to the first brake control device 110 via a cable.

[0043] The first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 may each be installed in wheels of a vehicle to provide braking force. The first EMB 21 may be a front-left EMB, the second EMB 22 may be a front-right EMB, the third EMB 23 may be a rear-left EMB, and the fourth EMB 24 may be a rear-right EMB.

[0044] An EMB can provide braking pressure to each wheel using power from an electric motor, unlike an existing hydraulic brake. The EMB can perform various braking controls required for autonomous vehicles or intelligent devices for constant-speed driving, such as anti-lock braking system (ABS) control, electronic stability control (ESC) control, and traction control system (TCS) control, in addition to normal braking control. For this purpose, the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 may each include EMB control devices (not shown). The EMB control devices of the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 can each detect whether the first wheel speed sensor 31, the second wheel speed sensor 32, the third wheel speed sensor 33, and the fourth wheel speed sensor 34 have failed.

[0045] In addition, the EMB control devices of the first EMB 21, the second EMB 22, the third EMB 23 and the fourth EMB 24 can respectively transmit the wheel speed signals received from the first wheel speed sensor 31, the second wheel speed sensor 32, the third wheel speed sensor 33 and the fourth wheel speed sensor 34 to the first brake control device 110 and the second brake control device 120.

[0046] The first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 may receive a first target braking torque and / or a second target braking torque from the first brake controller 110 and the second brake controller 120. Furthermore, the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 may perform braking controls on the respective wheels based on the first target braking torque and / or the second target braking torque.

[0047] When the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 receive both a first target braking torque and a second target braking torque, the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 can perform brake controls based on the first target braking torque. That is, while both the first brake control device 110 and the second brake control device 120 are operating normally, the first brake control device 110 can function as a main brake control device. This may be because the first brake control device 110 is connected to an electronic control unit (ECU) in the vehicle via the communication network 60 to perform additional control functions, such as ABS control, ESC control, and TCS control. The communication network 60 may be a body controller area network (CAN) or a vehicle control unit (VCU) CAN.

[0048] The first brake control device 110 may require various logics to perform the additional control functions, such as ABS, ESC, and TCS, in cooperation with the ECU in the vehicle, and accordingly, the first brake control device 110 may include a relatively complicated circuit configuration compared to the second brake control device 120. However, the disclosure is not limited thereto, and according to one embodiment, the second brake control device 120 may also be connected to the ECU in the vehicle via the communication network 60 and include a circuit configuration with high complexity by including logics to perform the additional control functions, such as ABS control, ESC control, and TCS control.

[0049] The first brake controller 110 may obtain a first target braking torque based on a first braking signal received from the first pedal sensor 11. Specifically, the first brake controller 110 may obtain a first target braking torque based on the first braking signal and wheel speed signals received from the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24. The first brake controller 110 may transmit the first target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0050] In a normal situation where no problem occurs in the electromechanical brake system 10, the second brake control device 120 may function as a main control device among the first brake control device 110 and the second brake control device 120 to obtain a target braking torque (second target braking torque) and transmit the target braking torque to the four EMBs, at which time the first brake control device 110 may perform additional controls such as ABS, TCS, and ESC.

[0051] Since the second brake control device 120 obtains a second target braking torque based on a first braking signal, a second braking signal, and a third braking signal from the first pedal sensor 11, the second pedal sensor 12, and the third pedal sensor 13, the second brake control device 120 can obtain a more precise target braking torque than the first brake control device 110 and perform fail-safe protection with respect to failures of at least one pedal sensor.

[0052] The communication network 60 can connect the first brake control device 110 to the ECU in the vehicle. Furthermore, the first local area network 70 can connect the first brake control device 110 to the second brake control device 120.

[0053] The first brake controller 110 may be connected to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 through the second local area network 80 to receive and transmit a first target braking torque and wheel speed signals. The second brake controller 120 may be connected to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 through the third local area network 90 to receive and transmit a second target braking torque and wheel speed signals.

[0054] The communication network 60, the first local area network 70, the second local area network 80, and the third local area network 90 may be vehicle communication networks (NTs). For example, the first brake controller 110, the second brake controller 120, the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 may receive and transmit signals or data through Ethernet, Media Oriented Systems Transport (MOST), Flexray, Controller Area Network (CAN), Local Interconnect Network (LIN), etc. Preferably, the first local area network 70, the second local area network 80, and the third local area network 90 may be implemented with CAN or Flexray. Furthermore, even more preferably, the communication network 60 may be implemented with a body CAN or VCU CAN to relay communications between the first brake controller 110 and the ECU in the vehicle.

[0055] The first battery 40 may be connected to the first pedal sensor 11, the first brake control device 110, the first EMB 21, and the fourth EMB 24 to supply them with power. The second battery 50 may be connected to the second pedal sensor 12, the third pedal sensor 13, the second brake control device 120, the second EMB 22, and the third EMB 23 to supply them with power.

[0056] As such, through an X-split configuration, where each of two batteries is connected to two EMBs at diagonal positions of four EMBs, normal brake control may be possible even if one of the two batteries has failed. Details of this will be discussed later with reference to Fig. 3 and Fig. 4 described.

[0057] As such, by including the first pedal sensor 11, the second pedal sensor 12, the third pedal sensor 13, the first brake control device 110, the second brake control device 120, the first battery 40, and the second battery 50, redundancy can be ensured with respect to a failure or breakdown that may occur in the electromechanical brake system 1.

[0058] In the following, various examples are used to describe how brake control is carried out with redundancy in the event of a failure of a specific component in the electromechanical brake system 1.

[0059] Referring to Fig. 1, a case is described in which a communication interruption occurs between the first brake control device 110 and the second brake control device 120.

[0060] If the first local area network 70 connecting the first brake control device 110 to the second brake control device 120 fails, communication between the first brake control device 110 and the second brake control device 120 may be interrupted. In this situation, the electromechanical brake system 1 may preferably use the second brake control device 120 for brake control. At this time, the first brake control device 110 may perform abnormal brake control such as ABS.

[0061] In the electromechanical brake system 1, the second local network 80 and the third local network 90 as well as the first local network 70 may also be affected by a failure or communication interruption.

[0062] If a failure has occurred in the second local area network 80, no information or signals required for brake control can be received or transmitted between the first brake control device 110 and the four EMBs. In this case, the second brake control device 120 can perform brake control on the four EMBs.

[0063] In contrast, if a failure has occurred in the third local area network 90, no information or signals required for brake control can be received or transmitted between the second brake control device 120 and the four EMBs. In this case, the first brake control device 110 can perform brake control on the four EMBs.

[0064] Fig. 3 shows a state in which the second battery 50 in the electromechanical brake system 1 of Fig. 1 has failed.

[0065] Referring to Fig. 3, the second battery 50 may be connected to the second pedal sensor 12, the third pedal sensor 13, the second brake control device 120, the second EMB 22, and the third EMB 23 to supply them with power. If the second battery 50 fails, the second pedal sensor 12, the third pedal sensor 13, the second brake control device 120, the second EMB 22, and the third EMB 23 may be turned off and thus deactivated. In this case, the first brake control device 110 may receive a first target braking torque based on a first braking signal from the first pedal sensor 11 and transmit the first target braking torque to the first EMB 21 and the fourth EMB 24. Accordingly, even if the second battery 50 fails, brake control at the first EMB 21 and the fourth EMB 24 may be possible, thereby maintaining the minimum braking performance required by legal regulations.That is, even in a failure situation of the second battery 50, a pedal sensor, a brake controller, and two EMBs can be maintained in an activated state by the first battery 40.

[0066] Fig. Fig. 4 shows a state in which the first battery 40 in the electromechanical brake system 1 of Fig. 1 has failed.

[0067] Referring to Fig. 4, the first battery 40 may be connected to the first pedal sensor 11, the first brake control device 110, the first EMB 21, and the fourth EMB 24 to supply them with power. If the first battery 40 has failed, the first pedal sensor 11, the first brake control device 110, the first EMB 21, and the fourth EMB 24 may be turned off and thus deactivated. In this case, the second brake control device 120 may receive a second target braking torque based on a second braking signal and a third braking signal from the second pedal sensor 12 and the third pedal sensor 13, and transmit the second target braking torque to the second EMB 22 and the third EMB 23. Accordingly, even if the first battery 40 has failed, brake control at the second EMB 21 and the third EMB 23 may be possible, thereby maintaining the minimum braking performance required by legal regulations.That is, even in a failure situation of the first battery 40, two pedal sensors, a brake controller, and two EMBs can be maintained in an activated state by the second battery 50. Accordingly, even in a failure situation of the first battery 40, the second brake control device 120 can detect a failure of the second pedal sensor 12 or the third pedal sensor 13 based on a second brake signal and a third brake signal.

[0068] Meanwhile, when the first brake control device 110 is deactivated, the second brake control device 120 cannot perform additional control functions such as ABS, ESC, and TCS, except for normal brake control, because the second brake control device 120 is not directly connected to the ECU through the communication network 60. Accordingly, the second brake control device 120 may not require a complicated circuit configuration for performing the additional control functions and may have a simpler configuration than the first brake control device 110. Instead, the second brake control device 120 may include logic for detecting a failure of the first pedal sensor 11, the second pedal sensor 12, or the third pedal sensor 13, unlike the first brake control device 110. Fig. 5 shows a state in which the first EMB 21 in the electromechanical brake system of Fig. 1 has failed.

[0069] The first brake control device 110 and the second brake control device 120 can detect a failure of an EMB control device of each of the first EMB 21, the second EMB 22, the third EMB 23 and the fourth EMB 24.

[0070] Referring to Fig. 5, when the first brake control device 110 and / or the second brake control device 120 detects a failure of an EMB control device of the first EMB 21, the first brake control device 110 and / or the second brake control device 120 may perform brake control on the second EMB 22, the third EMB 23, and the fourth EMB 24. At this time, the first brake control device 110 and / or the second brake control device 120 may compensate for a first target braking torque and / or a second target braking torque taking into account the failure of the first EMB 21, thereby performing normal brake control on the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0071] Even in a situation where a failure of any of the second EMB 22, the third EMB 23 or the fourth EMB 24 is detected, the same response procedure as in the situation where the first EMB 21 has failed can be applied.

[0072] Fig. Fig. 6 shows a state in which the second brake control device 120 in the electromechanical brake system 1 of Fig. 1 has failed.

[0073] Referring to Fig. 6, a limitation that occurs when the second brake control device 120 has failed may be that a failure of any of the first pedal sensor 11, the second pedal sensor 12, or the third pedal sensor 13 may not be detected. In this situation, the first brake control device 110, instead of the second brake control device 120, may obtain a first target braking torque based on a first braking signal and transmit the first target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0074] In contrast, a limitation that occurs when the first brake control device 110 has failed may be that additional control functions, such as ABS, ESC, and TCS, cannot be executed because the second brake control device 120 is not connected to the ECU in the vehicle through the communication network 60. In this situation, the second brake control device 120, instead of the first brake control device 110, may obtain a second target braking torque based on a first braking signal, a second braking signal, and a third braking signal, and transmit the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0075] In summary, when the second brake control device 120 has failed, normal brake control can be performed except that a failure of any one of the first pedal sensor 11, the second pedal sensor 12, or the third pedal sensor 13 cannot be detected, and when the first brake control device 110 has failed, normal brake control can be performed except that additional control functions such as ABS, ESC, and TCS cannot be performed. Accordingly, when any one of the first brake control device 110 or the second brake control device 120 has failed, another one that has not failed can transmit a first target braking torque or a second target braking torque to the EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24, thereby performing normal brake control.

[0076] Fig. Fig. 7 shows a state in which the first pedal sensor 11 in the electromechanical brake system 1 of Fig. 1 has failed.

[0077] Referring to Fig. 7, the second brake control device 120 may detect a failure of at least one of the first pedal sensor 11, the second pedal sensor 12, or the third pedal sensor 13 based on a first brake signal, a second brake signal, and a third brake signal. When the second brake control device 120 detects a failure of the first pedal sensor 11, the second brake control device 120 may obtain a second target braking torque based on a second brake signal and a third brake signal. The second brake control device 120 may transmit a failure signal of the first pedal sensor 11 to the first brake control device 110. The first brake control device 110, having received the failure signal of the first pedal sensor 11, may abort a calculation for obtaining a first target braking torque.

[0078] At this time, the second brake control device 120 may transmit the second target braking torque to the first brake control device 110 or to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24. Any of the methods described above may be applied, although a distinction may be made according to the methods.

[0079] For example, when the second brake control device 120 transmits the second target braking torque to the first brake control device 110, the first brake control device 110 may transmit the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24. Accordingly, the first brake control device 110 may function as a main brake control device and perform additional brake controls, such as ABS control, ESC control, and TCS control.

[0080] When the second brake control device 120 transmits the second target torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24, the second brake control device 120 can operate as a main brake control device and perform brake control faster than the method described above. Fig. 8 is a flowchart illustrating a method of controlling an electromechanical braking system according to one embodiment. Fig. 9 is a flowchart illustrating a method of controlling an electromechanical braking system according to one embodiment.

[0081] The electromechanical brake system 1 can Fig.1. That is, the electromechanical brake system 1 may include: the first pedal sensor 11, the second pedal sensor 12, and the third pedal sensor 13, which are configured to detect a pedal force applied to the brake pedal and generate a first brake signal, a second brake signal, and a third brake signal; the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24, which are installed in the respective wheels of the vehicle to provide a braking force; the first brake control device 110, which is connected to the first pedal sensor 11 and configured to obtain a first target braking torque based on the first brake signal and transmit the first target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24;the second brake control device 120, which is connected to the first pedal sensor 11 and the third pedal sensor 13 and is configured to obtain a second target braking torque based on the first brake signal, the second brake signal, and the third brake signal, and to transmit the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24; the first battery 40, which is configured to supply power to the first pedal sensor 11, the first brake control device 110, the first EMB 21, and the fourth EMB 24;and the second battery 50 configured to supply power to the second pedal sensor 12, the third pedal sensor 13, the second brake control device 120, the second EMB 22, and the third EMB 23, wherein, when the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 receive both the first target braking torque and the second target braking torque, the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 can perform brake control based on the first target braking torque.

[0082] The method of controlling the electromechanical brake system 1 may include: operation 810 of detecting a failure of at least one of the first battery 40, the second battery 50, the first pedal sensor 11, the second pedal sensor 12, the third pedal sensor 13, the first brake control device 110, and the second brake control device 120; and operation 820 of performing a brake control in the first brake control device 110 or the second brake control device 120 in response to the detected failure.

[0083] In operation 810 of detecting a failure, a failure of the first battery 40 may be detected (830). In this case, operation 820 of performing a brake control may further include operation 832 of obtaining a second target braking torque based on a first braking signal, a second braking signal, and a third braking signal in the second brake control device 120, and operation 834 of transmitting the second target braking torque to the second EMB 22 and the third EMB 23.

[0084] In operation 810 of detecting a failure, a failure of the second battery 50 may be detected (840). In this case, operation 820 of performing a brake control may further include operation 842 of obtaining a first target braking torque based on a first braking signal in the first brake control device 110, and operation 844 of transmitting the first target braking torque to the first EMB 21 and the fourth EMB 24.

[0085] In operation 810 of detecting a failure, a failure of the first pedal sensor 11 may be detected (850). In this case, operation 820 of performing a brake control may further include operation 852 of transmitting a failure signal of the first pedal sensor 11 to the first brake control device 110 in the second brake control device 120, operation 854 of obtaining a second target braking torque based on a second braking signal and a third braking signal in the second brake control device 120, and operation 856 of transmitting the second target braking torque to the first brake control device 110 in the second brake control device 120, or operation 858 of transmitting the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 in the second brake control device 120.

[0086] Operation 820 of performing a brake control may further include operation 858 of transmitting the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 in the first brake control device 110 when the first brake control device 110 receives the second target braking torque.

[0087] In operation 810 of detecting a failure, a failure of the second pedal sensor 12 or the third pedal sensor 13 may be detected (860). In this case, operation 820 of performing a brake control may further include: operation 862 of obtaining a first target braking torque and a second target braking torque based on sensor signals from the remaining pedal sensors that have not failed; and operation 858 of transmitting the first target braking torque and the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0088] In operation 810 of detecting a failure, a failure of the first brake control device 110 may be detected (870). In this case, the operation 820 of performing a brake control may further include: operation 872 of obtaining a second target braking torque in the second brake control device 120; and operation 858 of transmitting the second target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0089] In operation 810 of detecting a failure, a failure of the second brake control device 120 may be detected (880). In this case, operation 820 of performing a brake control may further include: operation 882 of obtaining a first target braking torque in the first brake control device 110; and operation 858 of transmitting the first target braking torque to the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24.

[0090] As described above, the electromechanical brake system 1 may include the brake pedal unit 10 including the first pedal sensor 11, the second pedal sensor 12, the third pedal sensor 13, and the second brake control device 120, the first brake control device 110, the first battery 40, the second battery 50, the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24. The first battery 40 may be connected to the first pedal sensor 11, the first brake control device 110, the first EMB 21, and the fourth EMB 24 to supply them with power. The second battery 50 may be connected to the second pedal sensor 12, the third pedal sensor 13, the second brake control device 120, the second EMB 22, and the third EMB 23 to supply them with power. 110 can be connected to the first pedal sensor 11, the second brake control device 120, the first EMB 21, the second EMB 22,The third EMB 23 and the fourth EMB 24 may be connected via a wire and the communication network 60. The second brake control device 120 may be connected to the first pedal sensor 11, the second pedal sensor 12, the third pedal sensor 13, the first brake controller 10, the first EMB 21, the second EMB 22, the third EMB 23, and the fourth EMB 24 via a cable and the communication network 60, thereby implementing the minimum braking performance required for an autonomous vehicle at low cost, even in the event of a failure or breakdown of some parts, which may generally occur in an autonomous driving situation.

[0091] According to one aspect of the disclosure, an electromechanical braking system capable of providing minimum braking power required for autonomous driving upon occurrence of a failure by ensuring redundancy of a pedal sensor, a battery, and a brake controller with a minimal configuration may be provided, and a method of controlling the electromechanical braking system may be provided.

[0092] Accordingly, it may be possible to implement brake control suitable for autonomous driving with minimal cost in various failure situations.

[0093] Example embodiments of the present disclosure have been described above. In the example embodiments described above, some components may be implemented as a "module." Here, the term "module" refers to, but is not limited to, a software and / or hardware component, such as a field programmable gate array (FPGA) or application-specific integrated circuit (ASIC), that performs particular tasks. A module may advantageously be configured to reside on the addressable storage medium and may be configured to execute one or more processors.

[0094] For example, a module can include components such as software components, object-oriented software components, class components, and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The operations provided in the components and modules can be combined into fewer components and modules or further divided into additional components and modules. Furthermore, the components and modules can be implemented to execute one or more CPUs in a device.

[0095] With that said, and in addition to the exemplary embodiments described above, embodiments may therefore be implemented by computer-readable code / instructions in / on a medium, e.g., a computer-readable medium, to control at least one processing element to implement each exemplary embodiment described above. The medium may correspond to any medium(s) that permits storage and / or transmission of the computer-readable code.

[0096] The computer-readable code may be recorded on a medium or transmitted over the Internet. The medium may include read-only memory (ROM), random-access memory (RAM), compact disk-read-only memories (CD-ROMs), magnetic tapes, floppy disks, and optical recording media. The medium may also be a non-transferable, computer-readable medium. The media may also be a distributed network such that the computer-readable code is stored, transmitted, and executed in a distributed manner. Furthermore, as one example only, the processing element may include at least one processor or at least one computer processor, where processing elements may be distributed and / or contained in a single assembly.

[0097] While exemplary embodiments have been described with reference to a limited number of embodiments, those skilled in the art, given the benefit of this disclosure, will appreciate that other embodiments may be developed that do not depart from the scope as disclosed herein. Accordingly, the scope should be limited only by the appended claims.

Claims

[1] Electromechanical braking system comprising: a first pedal sensor, a second pedal sensor, and a third pedal sensor configured to detect a pedal force applied to a brake pedal and generate a first brake signal, a second brake signal, and a third brake signal; a first electromechanical brake (EMB), a second EMB, a third EMB, and a fourth EMB, each installed in a plurality of wheels of a vehicle and configured to provide braking force to the plurality of wheels of the vehicle; a first brake controller connected to the first pedal sensor and configured to obtain a first target braking torque based on the first braking signal and to transmit the first target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB; and a second brake controller connected to the first pedal sensor, the second pedal sensor, and the third pedal sensor and configured to obtain a second target braking torque based on the first brake signal, the second brake signal, and the third brake signal and to transmit the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB, wherein the second brake controller is configured to detect a failure of at least one of the first pedal sensor, the second pedal sensor, or the third pedal sensor based on the first brake signal, the second brake signal, and the third brake signal. [2] The electromechanical brake system according to claim 1, wherein, based on a failure of one of the first brake controller and the second brake controller, another brake controller that has not failed is configured to transmit the first target braking torque or the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB. [3] An electromechanical brake system according to claim 1, wherein: the first pedal sensor, the first brake controller, the first EMB and the fourth EMB are powered by a first battery of the vehicle; and the second pedal sensor, the third pedal sensor, the second brake controller, the second EMB and the third EMB are powered by a second battery of the vehicle. [4] The electromechanical brake system according to claim 3, wherein, based on a failure of the first battery, the second brake controller is configured to obtain the second target braking torque based on the first braking signal, the second braking signal, and the third braking signal, and to transmit the second target braking torque to the second EMB and the third EMB. [5] The electromechanical brake system according to claim 3, wherein, based on a failure of the second battery, the second brake controller is configured to obtain the first target braking torque based on the first braking signal and to transmit the first target braking torque to the first EMB and the fourth EMB. [6] The electromechanical brake system according to claim 1, wherein the first EMB, the second EMB, the third EMB and the fourth EMB are configured to detect failures of a plurality of wheel speed sensors respectively installed in the plurality of wheels of the vehicle. [7] The electromechanical brake system according to claim 1, wherein the first EMB, the second EMB, the third EMB, and the fourth EMB are configured to receive a wheel speed signal from the plurality of wheel speed sensors respectively installed in the plurality of wheels of the vehicle, and to transmit the wheel speed signal to the first brake controller and the second brake controller. [8] The electromechanical brake system according to claim 7, wherein the first brake controller is configured to obtain the first target braking torque based on the first braking signal and the wheel speed signal, and the second brake controller is configured to obtain the second target braking torque based on the first braking signal, the second braking signal, the third braking signal, and the wheel speed signal. [9] An electromechanical brake system according to claim 1, wherein the first brake controller is connected to an electronic control unit (ECU) in the vehicle through a communication network and is configured to perform at least one control of an anti-lock braking system (ABS), an electronic stability control (ESC), or a traction control system (TCS). [10] The electromechanical brake system according to claim 1, wherein the first brake controller and the second brake controller are connected to a first local area network, and the second brake controller is configured to obtain the second target braking torque based on the second braking signal and the third braking signal upon detection of a failure of the first pedal sensor. [11] Electromechanical brake system according to claim 10, wherein the second brake controller is configured to transmit the second target braking torque to the first brake controller. [12] The electromechanical brake system according to claim 10, wherein the second brake controller is configured to transmit the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB. [13] The electromechanical brake system of claim 11, wherein the second brake controller is configured to transmit a failure signal of the second pedal sensor to the first brake controller, and the first brake controller is configured not to obtain the first target braking torque based on receipt of the failure signal. [14] The electromechanical brake system of claim 13, wherein the first brake controller is configured to transmit the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB based on receiving the second target braking torque. [15] The electromechanical brake system according to claim 1, wherein upon receiving both the first target braking torque and the second target braking torque, the first EMB, the second EMB, the third EMB, and the fourth EMB are configured to perform a brake control based on the first target braking torque. [16] A method of controlling an electromechanical brake system of a vehicle, comprising: a first pedal sensor, a second pedal sensor, a third pedal sensor, a first brake controller, a second brake controller, a first electromechanical brake (EMB), a second EMB, a third EMB, and a fourth EMB, wherein the first pedal sensor, the first brake controller, the first EMB, and the fourth EMB are powered by a first battery of the vehicle, and the second pedal sensor, the third pedal sensor, the second brake controller, the second EMB, and the third EMB are powered by a second battery of the vehicle, the method comprising: at the first pedal sensor, detecting a pedal force applied to a brake pedal by the first pedal sensor, the second pedal sensor and the third pedal sensor; at the first pedal sensor, generating a first brake signal, a second brake signal and a third brake signal by the second pedal sensor and the third pedal sensor; at the first brake controller connected to the first pedal sensor, obtaining a first target braking torque based on the first braking signal; at the first brake controller, transmitting the first target braking torque to the first EMB, the second EMB, the third EMB and the fourth EMB; at the second brake controller connected to the first pedal sensor, the second pedal sensor, and the third pedal sensor, obtaining a second target braking torque based on the first braking signal, the second braking signal, and the third braking signal; at the second brake controller, transmitting the second target braking torque to the first EMB, the second EMB, the third EMB and the fourth EMB; at the first EMB, the second EMB, the third EMB and the fourth EMB, performing a braking control based on the first target braking torque upon receiving both the first target braking torque and the second target braking torque; Detecting a failure of at least one of the first battery, the second battery, the first pedal sensor, the second pedal sensor, the third pedal sensor, the first brake controller, or the second brake controller; and at any brake controller of the first brake controller or the second brake controller, performing a brake control based on the detected failure. [17] The method of claim 16, wherein performing the brake control based on the detected failure comprises: at the second brake controller, obtaining the second target braking torque based on the first braking signal, the second braking signal, and the third braking signal; and at the second brake control, transmitting the second target braking torque to the second EMB and the third EMB. [18] The method of claim 16, wherein performing the brake control based on the detected failure comprises: at the first brake controller, obtaining the first target braking torque based on the first braking signal; and at the first brake control, transmitting the first target braking torque to the first EMB and the fourth EMB. [19] The method of claim 16, wherein performing the brake control obtaining comprises: at the second brake controller, transmitting a failure signal of the first pedal sensor to the first brake controller; at the second brake controller, obtaining the second target braking torque based on the second braking signal and the third braking signal; and at the second brake controller, transmitting the second target braking torque to the first brake controller or transmitting the second target braking torque to the first EMB, the second EMB, the third EMB and the fourth EMB. [20] The method of claim 19, further comprising, at the first brake controller, transmitting, upon receipt of the second target braking torque, the second target braking torque to the first EMB, the second EMB, the third EMB, and the fourth EMB.

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