阅读说明：本技术 车辆制动系统及其操作方法 (Vehicle brake system and method of operating the same ) 是由 黄佑铉 于 2021-05-11 设计创作，主要内容包括：公开了一种制动系统及其控制方法。提供的制动系统包括主制动器、辅助制动器、信号总线和通信单元。主制动器将制动力分配到每个车轮。发生故障时,辅助制动器代替主制动器运行。信号总线包括布置在主制动器和辅助制动器之间的一个或多个有线设备,并且在主制动器和辅助制动器之间传输关于存在或不存在故障的信号。通信单元在主制动器和辅助制动器之间传输操作状态信息。响应于通过信号总线检测到的主制动器的故障信号,辅助制动器实施为每个车轮提供制动力的准备。所述系统及其控制方法能够使辅助制动器在较短的时间内检测主制动器的故障,从而确保了车辆的冗余性。(A brake system and a control method thereof are disclosed. A braking system is provided that includes a service brake, an auxiliary brake, a signal bus, and a communication unit. The service brake distributes the braking force to each wheel. When a fault occurs, the auxiliary brake replaces the main brake to operate. The signal bus comprises one or more wired devices arranged between the service brake and the auxiliary brake and transmits signals between the service brake and the auxiliary brake regarding the presence or absence of a fault. The communication unit transmits operating state information between the service brake and the auxiliary brake. In response to a fault signal of the service brake detected via the signal bus, the auxiliary brake carries out a preparation for providing a braking force for each wheel. The system and the control method thereof enable the auxiliary brake to detect a failure of the main brake in a short time, thereby ensuring redundancy of the vehicle.)

1. A braking system comprising:

a service brake configured to provide a braking force to a wheel of a vehicle;

an auxiliary brake configured to provide a braking force to the wheel when the main brake is out of order;

a signal bus extending between the primary brake and the auxiliary brake and configured to transmit a fault status signal between the primary brake and the auxiliary brake, the signal indicating the presence or absence of a fault on the primary brake; and

a communication unit configured to transmit and receive operation state information to and from the service brake and the auxiliary brake,

wherein the auxiliary brake is configured to implement a preparation for providing braking force to a wheel upon receiving a fault status signal over the signal bus indicating that a fault is present on the primary brake.

2. The braking system of claim 1, wherein the fault on the service brake comprises:

the service brake being unable to provide a braking force to exert a deceleration on the wheels equal to or greater than a preset value; or

The foundation brake is incapable of operating an anti-lock braking system (ABS) or an Electronic Stability Control (ESC).

3. The braking system of claim 1, wherein the service brake comprises:

a hydraulic pump;

a motor configured to drive the hydraulic pump;

a hydraulic module configured to provide hydraulic pressure to the wheels; and

a control unit.

4. The braking system of claim 3, wherein the fault on the service brake comprises: a failure of at least one of the motor, the hydraulic module, and the control unit.

5. The braking system of claim 1, wherein:

the service brake includes: a motor, a Motor Current Sensor (MCS), a Motor Position Sensor (MPS), a valve relay, a hydraulic circuit, a supply voltage and a main controller unit, and

the fault on the service brake comprises: a fault in at least one of the motor, the MCS, the valve relay, the hydraulic circuit, the supply voltage, and the main controller unit.

6. The braking system of claim 1, wherein the auxiliary brake is configured to provide braking force to a wheel in response to the operating state information received from the communication unit and indicating a cause of failure of the primary brake.

7. The brake system of claim 1, wherein the preparation to provide braking force to a wheel includes replenishing brake fluid to the auxiliary brake.

8. The braking system of claim 1,

the wheel includes a front wheel and a rear wheel, and

the auxiliary brake is configured to provide a braking force to at least one of the front wheel and the rear wheel.

9. The braking system of claim 1, wherein the fault status signal comprises:

a first signal transmitted from the primary brake to the auxiliary brake and indicating that there is no fault on the primary brake; and

a second signal transmitted from the primary brake to the auxiliary brake and indicating that a fault exists on the primary brake.

10. A braking system according to claim 1, wherein the communication unit is configured to cause the primary brake to automatically transmit a cause of failure of the primary brake to the auxiliary brake.

11. A method for controlling a brake system of a vehicle comprising a primary brake and an auxiliary brake, the method comprising:

detecting a fault on the foundation brake, the foundation brake configured to generate fault information indicative of a cause of the fault;

in response to detecting a fault on the primary brake, causing the secondary brake to implement a preparation to provide braking force to a wheel of a vehicle;

determining whether the service brake has lost a braking function based on the failure information generated by the service brake after controlling the auxiliary brake to implement preparation for providing braking force to wheels; and

in response to determining that the primary brake has lost braking function, transferring control of the provision of braking force to the wheels from the primary brake to the auxiliary brake.

12. The method of claim 11, further comprising: transmitting the fault information generated by the primary brake to the auxiliary brake, the auxiliary brake being configured to provide a braking force to a wheel based on the fault information.

Technical Field

In some embodiments, the present disclosure relates to a brake system and a control method thereof.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

With the increasingly active development of vehicle autopilot technology, problems regarding the driving stability of an autopilot vehicle are emerging. When driving an autonomous vehicle, the risk of accidents increases when an abnormality occurs in the braking system during deceleration or braking.

As a solution of the prior art, in case of a problem of the brake system, an auxiliary brake has been additionally installed in the vehicle. By general definition, the control Unit of the primary brake is a Main Controller Unit (MCU), and the control Unit of the secondary brake is a Redundant Controller Unit (RCU). When the MCU detects the service brake is damaged, it transmits damage information to the RCU through Controller Area Network (CAN) communication of the vehicle. Accordingly, the RCU takes over control of the vehicle braking system from the MCU and participates in vehicle braking. With this brake system and control method, redundancy in braking performance of the vehicle can be ensured.

However, the related art involves a delay occurring in the standby time of the RCU due to the MCU transmitting the fault notification to the RCU through CAN communication. CAN communication typically has a communication period of 10 ms. The MCU takes 20ms to signal a fault to the RCU and transfer control. Thus, during the 20ms period, the primary brake system remains in the blank time to cause it to operate abnormally, while the auxiliary brake system is not authorized to transfer control. When the vehicle is running at a high speed, the 20ms blank may be fatal to the safety of the driver.

Disclosure of Invention

In accordance with at least one embodiment, the present disclosure provides a braking system comprising: the brake system comprises a main brake, an auxiliary brake, a signal bus and a communication unit. The foundation brake is configured and arranged to provide a braking force to each wheel of the vehicle. The auxiliary brake is configured and arranged to operate in place of the primary brake in the event of a failure at the primary brake. The signal bus includes at least one or more wired devices disposed between the primary brake and the auxiliary brake and is configured to transmit a signal between the primary brake and the auxiliary brake indicating the presence or absence of a fault. The communication unit is configured and arranged to transmit and receive operating state information between the primary brake and the auxiliary brake. In this case, the auxiliary brake is used to carry out a preparation for providing a braking force for each wheel of the vehicle in response to the detection of a fault signal of the service brake via the signal bus.

According to another embodiment, the present disclosure provides a method for controlling a brake system of a vehicle, comprising: detecting a malfunction of a primary brake by a control unit of the primary brake, and when it is determined that a malfunction occurs on the primary brake, transmitting information on the malfunction to an auxiliary brake by a digital signal, and upon receiving the digital signal, performing preparation by the auxiliary brake to provide a braking force to each wheel of a vehicle and transmitting information on a cause of the malfunction of the primary brake to the auxiliary brake, and when it is determined that the primary brake has lost a braking function, receiving, by the auxiliary brake, a shift of control of providing the braking force from the primary brake.

Drawings

Fig. 1 is a schematic view of a braking system according to at least one embodiment of the present disclosure.

Fig. 2 is a block diagram of a braking system during normal operation of a vehicle according to at least one embodiment of the present disclosure.

Fig. 3 is a block diagram of a braking system of a vehicle when a foundation brake fails according to at least one embodiment of the present disclosure.

Fig. 4 is a flow chart of a control method of a braking system according to at least one embodiment of the present disclosure.

Detailed Description

Accordingly, in at least one embodiment, the present disclosure is directed to improving the backup performance of an auxiliary brake in a braking system.

Some exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings. In the following description, the same reference numerals preferably denote the same elements, although the elements are shown in different drawings. In addition, in the following description of some embodiments, a detailed description of known functions and configurations incorporated herein will be omitted for clarity and conciseness.

Moreover, the use of alphanumeric codes such as first, second, i), ii), a), b), etc. to describe each element is for the purpose of distinguishing one element from another, and does not imply or claim material, order, or sequence of elements. Throughout the specification, when a component "comprises" or "comprising" an element is meant to include the other element as well, it does not exclude the other element unless there is a specific description to the contrary.

Fig. 1 is a schematic view of a braking system according to at least one embodiment of the present disclosure.

As shown in fig. 1, the braking system may include some or all of the following: a master cylinder 110, a service brake or service brake system 120, an auxiliary brake or auxiliary brake system 130 and a signal bus 140, a communication unit 150, a first flow path 160, a second flow path 170 and wheels 180a, 180 b.

The master cylinder 110 is configured to have at least one chamber to generate hydraulic pressure. The master cylinder 110 is a device that generates hydraulic pressure to discharge brake fluid.

The first flow path 160 is a passage through which the brake fluid moves between the master cylinder 110 and the service brake 120 and between the master cylinder 110 and the auxiliary brake 130. Unlike fig. 1 in which the primary brake 120 and the auxiliary brake 130 are arranged in parallel, they may be connected in series. In this case, the first flow path 160 is provided only between the master cylinder 110 and the service brake 120.

The second flow path 170 is a passage for supplying the hydraulic pressure generated from the service brake 120 and the auxiliary brake 130 to each wheel 180a, 180 b. The second flow path 170 shown in fig. 1 schematically shows the flow of hydraulic pressure, and the second flow path 170 is not limited to the arrangement shown in fig. 1.

The signal bus 140 is disposed between the primary brake 120 and the auxiliary brake 130 and includes one or more conductors adapted to transmit digital signals between the primary brake 120 and the auxiliary brake 130 indicating the presence or absence of a fault. The digital signal includes a first signal (high) and a second signal (low).

For example, in its normal operation, the primary brake 120 transmits a first signal to the auxiliary brake 130 via the signal bus 140. Conversely, when the power of the service brake 120 is turned off, the second signal is transmitted to the auxiliary brake 130. Using these signals, the primary brake 120 and the auxiliary brake 130 may monitor each other. The time taken to transmit the first signal and the second signal is less than 1 ms.

The communication unit 150 is arranged to transmit and receive operation state information to and from the service brake 120 and the auxiliary brake 130. The communication unit 150 may communicate using a Controller Area Network (CAN). The communication unit 150 serves to transmit and receive signals between the service brake 120 and the auxiliary brake 130 and between components in the vehicle that require communication.

Typically, the signal transmission period of the communication unit 150 is about 10 ms. For example, when an abnormal situation occurs in the service brake 120, the service brake 120 may notify the abnormal situation to the auxiliary brake 130 through CAN communication and transmit a signal for transferring the braking control authority of the brake system to the auxiliary brake 130, which may take about 20 ms.

The service brakes 120 are configured to provide braking force to the respective wheels. The service brake 120 receives an electric signal from an input terminal of a brake pedal and generates hydraulic pressure in a fluid by a mechanical operation. The service brake 120 may implement functions of an anti-lock brake system (ABS), an Electronic Stability Control (ESC), etc., which are safe driving functions while individually controlling hydraulic pressure supplied to each wheel.

The service brake 120 includes some or all of the following mid-to-high ends: the hydraulic control system includes a hydraulic pump, a motor configured to drive the hydraulic pump, a hydraulic module configured to provide hydraulic pressure to each wheel, and a control unit. The configuration of the foundation brake 120 is well known and will not be described in detail herein. The foundation brake 120 responds to an abnormality occurring at any component of the foundation brake 120 (e.g., a hydraulic pump, a motor, and a control unit) to transmit a fault signal to the auxiliary brake 130 through the signal bus 140.

Even when the service brake 120 determines that there is no abnormality in the hydraulic pump, the motor, the hydraulic module, and the control unit, when the service brake 120 fails to achieve a vehicle deceleration equal to or greater than a preset value, it performs self-monitoring to transmit a fault signal to the auxiliary brake 130 through the signal bus 140. For example, when the vehicle is decelerating, the foundation brake 120 with normal performance may generate more than 6.5m/s²Is reduced (about 0.65 times the acceleration due to gravity). When the service brake 120 cannot generate more than 6.5m/s²At deceleration, the auxiliary brake 130 needs to be implemented quickly as a backup for the primary brake 120.

Even after determining that there is no abnormality in the hydraulic pump, the motor, the hydraulic module, and the control unit, when the service brake 120 similarly transmits a fault signal to the auxiliary brake 130, the service brake 120 may detect a possible defect in the ABS and ESC functions.

The auxiliary brake 130 is arranged to operate in place of the primary brake 120 when the primary brake 120 fails. The auxiliary brake 130 may be arranged in parallel as shown in fig. 1, but is not limited to this arrangement, and it may also be arranged in series with the primary brake 120.

The auxiliary brake 130 is not limited to the method of sharing the second flow path 170 with the foundation brake 120 as shown in fig. 1, and it may have a separate braking mechanism disposed in addition to the foundation brake 120. For example, the auxiliary brake 130 may provide braking force to each wheel 180 with a separate flow path arranged independently of the second flow path 170.

The auxiliary brake 130 may have a function and performance comparable to the primary brake 120. The auxiliary brake 130 may have a minimum function for maintaining safety in an emergency (e.g., the service brake 120 cannot be operated), for example, a function of controlling braking only on the front wheels 180a by generating hydraulic pressure only on the front wheels 180 a. Alternatively, the auxiliary brake 130 may have a function of controlling not only the front wheels 180a but also the rear wheels 180b of the vehicle.

When a fault occurs, the primary brake 120 transmits signals to the auxiliary brake 130 primarily using the signal bus 140. When any one of the components of the service brake 120 malfunctions while the vehicle is driving or braking, the service brake 120 transmits a second signal to the auxiliary brake 130. In summary, when the service brake 120 is operating normally, it transmits a first signal to the auxiliary brake 130, and when the service brake 120 is malfunctioning, it transmits a second signal to the auxiliary brake 130. Using these signals, the auxiliary brake 130 can continuously monitor the status of the primary brake 120.

When the auxiliary brake 130 detects a fault condition of the primary brake 120 via the signal bus 140, the auxiliary brake 130 prepares to provide braking force to the respective wheels 180 before it receives control of the braking system transferred from the primary brake 120. For example, the preparing may include pre-generating hydraulic pressure by the auxiliary brake 130.

Once the auxiliary brake 130 receives the operation state information indicating the cause of the failure of the foundation brake 120 through the communication unit 150, the brake system control authority of the foundation brake 120 is transferred to the auxiliary brake 130. In the case where the control authority is transferred, the auxiliary brake 130 is used to provide braking force to each wheel in place of the foundation brake 120. In other words, the auxiliary brake 130 controls the braking system of the vehicle.

Fig. 2 is a block diagram of a braking system in normal operation according to at least one embodiment of the present disclosure. Fig. 3 is a block diagram of a braking system in the event of a foundation brake failure in accordance with at least one embodiment of the present disclosure.

As shown in fig. 2, once the braking input 200 is generated by the driver or an autopilot signal, the braking input 200 is transmitted to the primary brake 120 or the auxiliary brake 130. In response to the braking input 200, the primary brake 120 or the auxiliary brake 130 controls each wheel by providing a braking force to each wheel. Typically, the foundation brake 120 exclusively receives the brake input 200 without an anomaly.

The foundation brake 120 transmits a fault signal to the auxiliary brake 130 in response to an abnormality of the foundation brake 120 at any one of the following components of the foundation brake system 120: a motor 211, a motor current sensor (MCP) 212, a Motor Position Sensor (MPS) 213, a valve relay 214, a hydraulic circuit 215, a supply voltage 216, and a Main Controller Unit (MCU) 217.

Specifically, it is determined whether the service brake 120 has lost safe driving functions such as ABS and ESC by further determining whether there is a malfunction of a Wheel Slip Sensor (WSS).

The supply voltage 216 may encounter anomalies such as an off or low voltage condition. When the supply voltage 216 is off, the second signal will be automatically transmitted to the auxiliary brake 130, and in the case of a low voltage, the MCU 217 will detect the low voltage and similarly transmit the second signal to the auxiliary brake 130.

The method for determining the fault comprises the following steps: determining a signal base when a preset threshold is exceeded, determining that no signal is received from the sensor for a predetermined time or more, and/or comparing several signal values to ascertain an abnormal value that occurs in any one signal alone, thereby determining a fault condition.

The auxiliary brake 130 starts preparing upon receiving a fault occurrence signal indicating a fault of the primary brake 120 via the signal bus 140. While the auxiliary brake 130 is preparing, the brake input 200 is prevented from being transmitted to the auxiliary brake 130.

Referring to fig. 3, the braking input 200 is transferred to the auxiliary brake 130 only after the auxiliary brake 130 receives the operation state information indicating the cause of the failure of the primary brake 120 through the communication unit 150 and the braking system control authority of the primary brake 120 is transferred to the auxiliary brake 130.

In this way, the vehicle brake system according to at least one embodiment of the present disclosure advances or accelerates the standby preparation time of the auxiliary brake 130 by using the signal bus 140 having a higher transmission speed than the communication unit 150. This improvement of the standby function contributes to driving the vehicle more safely when the driver is driving at high speed, and in particular has the effect of increasing the stability of the automatic vehicle.

Fig. 4 is a flow chart of a control method of a braking system according to at least one embodiment of the present disclosure.

As shown in fig. 4, the control method of the brake system may substantially include six process steps.

First, it is determined whether a malfunction occurs on some components of the service brake 120 (S410). The foundation brake 120 determines a malfunction occurring on the foundation brake 120 by determining when an abnormality has occurred on some components of the foundation brake 120, when the foundation brake 120 fails to exhibit a braking capability corresponding to a deceleration rate higher than a preset value, or when the foundation brake 120 has lost its function to such an extent that the ABS and ESC functions cannot be implemented. When no failure occurs in the foundation brake 120, the redundancy control is terminated.

When the service brake 120 determines that it is out of order, it notifies the auxiliary brake 130 of the out-of-order by using a digital signal (S420). The digital signal consists of both a high and a low signal, the low of which is transmitted to the auxiliary brake 130, for example, in response to the occurrence of a malfunction of the service brake 120. In the case of using the digital signal alone, the auxiliary brake 130 only identifies whether the primary brake 120 has failed, without knowing the exact cause of the failure on the primary brake 120.

The auxiliary brake 130 performs preparation for providing braking force to each wheel (S430). The time when the auxiliary brake 130 receives the cause of the failure through the communication unit 150 and starts to generate the wheel hydraulic pressure is typically 20ms after the service brake 120 fails. However, the auxiliary brake 130 receives a fault signal within a short time of 1ms via the signal bus 140 directly wired between the primary brake 120 and the auxiliary brake 130, which allows the auxiliary brake 130 to be prepared faster than before.

The service brake 120 transmits a signal containing operation state information indicating a cause of a fault on the service brake 120 to the auxiliary brake 130 through the communication unit 150 (S440). Based on the operation state information transmitted through the communication unit 150, the auxiliary brake 130 determines whether the service brake 120 can exhibit a normal braking function in the event of abnormality of the service brake 120 (S450). Upon determining that the foundation brake 120 has not lost the braking function, the auxiliary brake 130 cancels the preparation and ends the control (S451).

Upon determining that the foundation brake 120 has lost the braking function, the auxiliary brake 130 receives control of providing braking force transferred from the foundation brake 120 (S460). In other words, the auxiliary brake 130 controls the braking system.

By this method for controlling the brake system of the vehicle, the backup performance of the auxiliary brake 130 is accelerated to exhibit a better backup function than the related art. When at least one embodiment of the present disclosure is particularly applied to an autonomous vehicle, safety of vehicle occupants can be improved by improving braking redundancy.

As described above, according to some embodiments of the present disclosure, a brake system for a vehicle and a control method thereof enable an auxiliary brake to detect a failure of a primary brake in a shorter time than that achieved in the past using a signal bus, thereby ensuring redundancy of the vehicle.

Although exemplary embodiments of the present disclosure have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as claimed. Accordingly, exemplary embodiments of the present disclosure have been described for the sake of brevity and clarity. The scope of the technical idea of the present embodiment is not limited by the description. Accordingly, one of ordinary skill will appreciate that the scope of the claimed invention is not limited by the explicitly described embodiments.