APPARATUS AND METHOD OF CONTROLLING VEHICULAR BRAKING

A method and apparatus for controlling braking of a vehicle are provided. The apparatus includes an in-wheel motor installed in a wheel to rotate the wheel, an electro-mechanical brake installed in the wheel to perform braking, a vehicular speed sensor to measure a speed of the vehicle, and a processor to: compute a required braking force, in response to receiving a signal initiated by a brake pedal; control braking by distributing the required braking force to the electro-mechanical brake and the in-wheel motor; determine a braking state according to a speed of the vehicle and recompute a braking torque for the in-wheel motor; and in case the electro-mechanical brake fails to operate, control the in-wheel motor to bring the vehicle to a stop.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit under 35 USC § 119 of Korean Patent Application No. 10-2023-0128252, filed on Sep. 25, 2023, in the Korean Intellectual Property Office, the entire disclosures of which are hereby incorporated by reference for all purposes.

BACKGROUND

Exemplary embodiments relate to an apparatus for and a method of controlling vehicular braking, the apparatus and the method being capable of controlling braking of a vehicle having four wheels that operate independently.

2. Discussion of Related Art

In recent years, there has been a trend toward the development of vehicles, each having four wheels that all independently drive and brake and can independently steer.

In the vehicle having four wheels that independently operate, a drive apparatus (a motor) for driving the vehicle, a steering apparatus, and a brake are included in one wheel. Thus, the wheel independently drives and can control the direction of the vehicle.

The related art relating to a vehicle capable of independent drive and steering is disclosed in Korean Patent Application Publication No. 10-2009-0062321 (Independent drive and traveling system of in-wheel drive electric vehicle and method of controlling same)

However, in the case of the vehicle capable of independent drive and steering, each wheel can be controlled independently, but in a case where a brake fails to operate, this may cause a problem with vehicle braking.

Accordingly, there is a need to provide a method of braking the vehicle in a case where the brake fails to operate.

SUMMARY

Various embodiments of the present disclosure, which are contrived to address the above-mentioned problem, are directed to an apparatus for and a method of controlling vehicular braking, the apparatus and the method being capable of stably performing braking in response to the failure of a brake in a vehicle capable of four-wheel drive independent control.

In a general aspect of the disclosure, an apparatus for controlling braking a vehicle includes: an in-wheel motor installed in a wheel and configured to rotate the wheel; an electro-mechanical brake installed in the wheel and configured to perform braking; a vehicular speed sensor configured to measure a speed of the vehicle; and a processor configured to: compute a required braking force in response to receiving a signal initiated by a brake pedal; control braking by distributing the required braking force to the electro-mechanical brake and the in-wheel motor; determine a braking state according to the speed of the vehicle and recompute a braking torque for the in-wheel motor; and in case the electro-mechanical brake fails to operate, control the in-wheel motor to bring the vehicle to a stop.

The processor may be further configured to: when the signal is input from the brake pedal, check a state of charge (SOC) of a battery; in case the SOC of the battery is above a first setting value, control the electro-mechanical brake to perform the braking; and in case the SOC is at or below the first setting value, distribute the required braking force to the in-wheel motor and the electro-mechanical brake.

The processor may be further configured to: in case the electro-mechanical brake fails to operate, determine, according to the signal from the brake pedal, whether sudden braking is required; and when sudden braking is required, control the in-wheel motor to operate at maximum braking torque.

The processor may be further configured to: determine whether sudden braking is required when the electro-mechanical brake fails to operate; determine whether the vehicle is in a speed-reduced state when a sudden braking-required situation is not reached; maintain braking torque for the in-wheel motor when the vehicle is in the speed-reduced state; and recompute the braking torque for the in-wheel motor when the vehicle is not in the speed-reduced state.

The processor may be further configured to: stop the braking that uses the in-wheel motor when the speed of the vehicle is lower than a preset speed; and perform the braking by controlling rear wheels of the vehicle in a toe-in configuration manner.

The processor may be further configured to disperse and distribute the braking force to a plurality of the in-wheel motors and a plurality of the electro-mechanical brakes, based on the required braking force.

The processor may be further configured to, in a case the brake signal is input and the SOC is above the first setting value, control the electro-mechanical brake to perform braking without controlling the in-wheel motor to perform braking.

The processor may be further configured to control the in-wheel motor to generate reverse torque to perform braking.

In another general aspect of the disclosure, A processor-implemented method of controlling braking of a vehicle, includes: computing a required braking force in response to receiving a signal initiated a brake pedal; controlling braking by distributing the required braking force to an electro-mechanical brake and an in-wheel motor; determining a braking state according to a speed of the vehicle in case the electro-mechanical brake fails to operate; and controlling the in-wheel motor by recomputing braking torque for the in-wheel motor according to the braking state.

The controlling of the braking may include: controlling the braking using the electro-mechanical brake in case a state of charge (SOC) of a battery is above a first setting value, after checking the SOC of the battery when the signal is input from the brake pedal; and controlling the braking by distributing the required braking force to the in-wheel motor and the electro-mechanical brake in case the SOC of the battery is at or below the first setting value.

The determining of the braking state may include: determining, according to the signal from the brake pedal, whether sudden braking is required, in case the electro-mechanical brake fails to operate; controlling the in-wheel motor to operate at a maximum braking torque when sudden braking is required; and determining whether the vehicle is in a speed-reduced state when sudden braking is not required.

The determining of whether the vehicle is in the speed-reduced state may include: maintaining braking torque for the in-wheel motor when the vehicle is in the speed-reduced state; and recomputing the braking torque for the in-wheel motor when the vehicle is not in the speed-reduced state.

The method may further include: stopping the braking that uses the in-wheel motor when the speed of the vehicle is below a preset speed; and performing the braking by controlling rear wheels of the vehicle in a toe-in configuration manner.

The method may further include: dispersing and distributing the braking force to a plurality of the in-wheel motors and a plurality of the electro-mechanical brakes, based on the required braking force.

The method may further include: in case the brake signal is input and the SOC is above the first setting value, controlling the electro-mechanical brake to perform braking without controlling the in-wheel motor to perform braking.

The method may further include: controlling the in-wheel motor to generate reverse torque to perform braking.

The apparatus for and the method of controlling vehicular braking according to the embodiments of the present disclosure can perform the braking using the in-wheel motor and the steering apparatus in a vehicle having four wheels that independently drive and steer. Thus, although the brake fails to operate, the apparatus and the method can safely bring the vehicle to a stop.

The apparatus for and the method of controlling vehicular braking according to the embodiments of the present disclosure can effectively perform the braking according to a situation, thereby increasing the reliability.

DETAILED DESCRIPTION

The method according to example embodiments may be embodied as a program that is executable by a computer, and may be implemented as various recording media such as a magnetic storage medium, an optical reading medium, and a digital storage medium.

Various techniques described herein may be implemented as digital electronic circuitry, or as computer hardware, firmware, software, or combinations thereof. The techniques may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device (for example, a computer-readable medium) or in a propagated signal for processing by, or to control an operation of a data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program(s) may be written in any form of a programming language, including compiled or interpreted languages and may be deployed in any form including a stand-alone program or a module, a component, a subroutine, or other units suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

Processors suitable for execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. Elements of a computer may include at least one processor to execute instructions and one or more memory devices to store instructions and data. Generally, a computer will also include or be coupled to receive data from, transfer data to, or perform both on one or more mass storage devices to store data, e.g., magnetic, magneto-optical disks, or optical disks. Examples of information carriers suitable for embodying computer program instructions and data include semiconductor memory devices, for example, magnetic media such as a hard disk, a floppy disk, and a magnetic tape, optical media such as a compact disk read only memory (CD-ROM), a digital video disk (DVD), etc. and magneto-optical media such as a floptical disk, and a read only memory (ROM), a random access memory (RAM), a flash memory, an erasable programmable ROM (EPROM), and an electrically erasable programmable ROM (EEPROM) and any other known computer readable medium. A processor and a memory may be supplemented by, or integrated into, a special purpose logic circuit.

The processor may run an operating system (OS) and one or more software applications that run on the OS. The processor device also may access, store, manipulate, process, and create data in response to execution of the software. For purpose of simplicity, the description of a processor device is used as singular; however, one skilled in the art will be appreciated that a processor device may include multiple processing elements and/or multiple types of processing elements. For example, a processor device may include multiple processors or a processor and a controller. In addition, different processing configurations are possible, such as parallel processors.

The present specification includes details of a number of specific implements, but it should be understood that the details do not limit any invention or what is claimable in the specification but rather describe features of the specific example embodiment. Features described in the specification in the context of individual example embodiments may be implemented as a combination in a single example embodiment. In contrast, various features described in the specification in the context of a single example embodiment may be implemented in multiple example embodiments individually or in an appropriate sub-combination. Furthermore, the features may operate in a specific combination and may be initially described as claimed in the combination, but one or more features may be excluded from the claimed combination in some cases, and the claimed combination may be changed into a sub-combination or a modification of a sub-combination.

It should be understood that the example embodiments disclosed herein are merely illustrative and are not intended to limit the scope of the invention. It will be apparent to one of ordinary skill in the art that various modifications of the example embodiments may be made without departing from the spirit and scope of the claims and their equivalents.

Hereinafter, with reference to the accompanying drawings, embodiments of the present disclosure will be described in detail so that a person skilled in the art can readily carry out the present disclosure. However, the present disclosure may be embodied in many different forms and is not limited to the embodiments described herein.

In the following description of the embodiments of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear. Parts not related to the description of the present disclosure in the drawings are omitted, and like parts are denoted by similar reference numerals.

In the present disclosure, components that are distinguished from each other are intended to clearly illustrate each feature. However, it does not necessarily mean that the components are separate. That is, a plurality of components may be integrated into one hardware or software unit, or a single component may be distributed into a plurality of hardware or software units. Thus, unless otherwise noted, such integrated or distributed embodiments are also included within the scope of the present disclosure.

In the present disclosure, components described in the various embodiments are not necessarily essential components, and some may be optional components. Accordingly, embodiments consisting of a subset of the components described in one embodiment are also included within the scope of the present disclosure. In addition, embodiments that include other components in addition to the components described in the various embodiments are also included in the scope of the present disclosure.

Hereinafter, with reference to the accompanying drawings, embodiments of the present disclosure will be described in detail so that a person skilled in the art can readily carry out the present disclosure. However, the present disclosure may be embodied in many different forms and is not limited to the embodiments described herein.

In the following description of the embodiments of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear. Parts not related to the description of the present disclosure in the drawings are omitted, and like parts are denoted by similar reference numerals.

In the present disclosure, when a component is referred to as being “linked,” “coupled,” or “connected” to another component, it is understood that not only a direct connection relationship but also an indirect connection relationship through an intermediate component may also be included. In addition, when a component is referred to as “comprising” or “having” another component, it may mean further inclusion of another component not the exclusion thereof, unless explicitly described to the contrary.

In the present disclosure, the terms first, second, etc. are used only for the purpose of distinguishing one component from another, and do not limit the order or importance of components, etc., unless specifically stated otherwise. Thus, within the scope of this disclosure, a first component in one exemplary embodiment may be referred to as a second component in another embodiment, and similarly a second component in one exemplary embodiment may be referred to as a first component.

In the present disclosure, components that are distinguished from each other are intended to clearly illustrate each feature. However, it does not necessarily mean that the components are separate. That is, a plurality of components may be integrated into one hardware or software unit, or a single component may be distributed into a plurality of hardware or software units. Thus, unless otherwise noted, such integrated or distributed embodiments are also included within the scope of the present disclosure.

In the present disclosure, components described in the various embodiments are not necessarily essential components, and some may be optional components. Accordingly, embodiments consisting of a subset of the components described in one embodiment are also included within the scope of the present disclosure. In addition, exemplary embodiments that include other components in addition to the components described in the various embodiments are also included in the scope of the present disclosure.

The present disclosure will be described below with reference to the accompanying drawings.

FIG.1is a view schematically illustrating a configuration of a four-wheel drive independent control vehicle10in which an embodiment of the present disclosure finds application.

As illustrated inFIG.1, the vehicle10has four wheels21to24that can operate independently.

The vehicle10includes a drive apparatus (an in-wheel motor) for driving, a steering apparatus, and a braking apparatus (a brake) in each wheel. These apparatuses independently drive and brake and can control the direction of the vehicle10.

The vehicle10can independently control four wheels21to24and thus can rotate in place or move horizontally in the axial direction.

These independent control capabilities enable the vehicle10to provide various types of mobility that are distinct from existing types of mobility.

For example, the purpose-built vehicle (PBV), a purpose-built mobility solution, has been developed with diverse implementation approaches as an innovative transportation solution for the purpose of prioritizing mobility and utility over a mere transportation solution.

FIG.2is a block diagram schematically illustrating a configuration of an apparatus100for controlling vehicular braking according to a first embodiment of the present disclosure.

As illustrated inFIG.2, the apparatus100for controlling vehicular braking according to the present disclosure may include a memory120, a sensor140, an electro-mechanical brake (EMB)170, a brake pedal190, a battery management system (BMS)150, an in-wheel module160for four wheels, and a processor110.

The apparatus100for controlling vehicular braking may further include a communication unit (not illustrated) for communication within the vehicle10and communication with the outside. For example, the communication unit can transmit and receive data within the vehicle10using CAN communication or LIN communication. Furthermore, the communication unit can transmit and receive data to and from the outside using communication standards such as vehicle-to-vehicle (V2V) communication, Ethernet, WiFi, and Bluetooth.

The sensor140may include a vehicular speed sensor141and a torque sensor142. The sensor140may further include a motor angle sensor, a steering angle sensor, a brake pedal sensor, a voltage sensor, a current sensor, and a temperature sensor, among other sensors, and descriptions thereof are omitted.

The vehicular speed sensor141detects a traveling speed of the vehicle10.

The torque sensor142measures braking force acting on each wheel.

The battery management system (BMS)150controls a battery in such a manner that the battery is charged or that an output of the battery is supplied to the processor110and the in-wheel module160. In addition, the battery management system (BMS)150can check a state of charge (SOC) of the battery (not illustrated) and can detect a failure of the battery.

Stored in the memory120can be data for traveling, driving, braking, and braking of the vehicle10, data measured from the sensor140, and state data of the battery. In addition, stored in the memory120can be data for the in-wheel module160.

Stored in the memory120can be at least one of the following algorithms: a steering control algorithm, a drive control algorithm, a braking control algorithm, or a traveling control algorithm.

Examples of the memory120may include nonvolatile memories, such as a random access memory (RAM), a ROM, electrically erased programmable ROM (EEPROM), and a flash memory, and other memory devices.

The electro-mechanical brake (EMB)170applies braking torque to the wheel, according to the braking force computed by converting force acting on the brake pedal190into an electrical signal, and thus performs braking. In addition, the electro-mechanical brake (EMB)170may include a button and a switch. The electro-mechanical brakes (EMBs)170can transfer the braking force to the four wheels21to24, respectively, based on a signal that is input by operating the button or the switch.

The electro-mechanical brakes (EMBs)170are provided on the four wheels21to24, respectively, and can independently brake the four wheels21to24.

The electro-mechanical brake (EMB)170can control a posture of the vehicle10by integrally controlling ABS, TCS, BAS, and electronic stability program (ESP) functions.

In a case where the brake pedal190is operated by a driver, the brake pedal190changes and applies a signal according to the degree of operation (pushing). The vehicle10operates the electro-mechanical brakes (EMBs)170according to the signal of the brake pedal190, thereby reducing a speed of the vehicle10or bringing the vehicle10to a stop.

The in-wheel module160is installed in the four wheels21to24and may include drive apparatuses, braking apparatuses, suspensions, and steering apparatuses. In this case, the drive apparatus is an in-wheel motor180, and the braking apparatus is an electronic-mechanical brake (EMB).

The in-wheel module160drives the in-wheel motors180of the four wheels21to24according to a control signal applied from the processor110, thereby enabling the vehicle10to travel. The in-wheel module160can reduce the speed of the vehicle10by controlling the electronic-mechanical brakes (EMBs)170. The in-wheel module160can control the directions of the four wheels21to24through the steering apparatuses.

The in-wheel module160can brake the vehicle10through the electro-mechanical brakes (EMBs)170. In addition, the in-wheel module160can brake the vehicle10by controlling the in-wheel motors180and thus generating reverse torque.

The in-wheel module160includes first to fourth in-wheel modules161to164, which are installed in the four wheels21to24, respectively. The in-wheel motors180are installed in first to fourth in-wheel modules161to164, respectively. The electro-mechanical brakes (EMBs)170may be installed in the first to fourth in-wheel modules161to164, respectively.

The first in-wheel module161is installed in a front left wheel, the second in-wheel module162in a front right wheel, the third in-wheel module163in a rear left wheel, and the fourth in-wheel module164in a rear right wheel.

The processor110may include at least one micro-processor and can operate based on the algorithm stored in the memory120.

The processor110can determine a traveling state of the vehicle10based on the SOC of the battery and on data that are input from the sensor140.

The processor110computes required braking force according to the degree of operation of the brake pedal190. The processor110performs braking by controlling the in-wheel motors180and the electro-mechanical brakes (EMBs)170, thereby enabling the vehicle10to reduce the speed thereof and to bring the vehicle10to a stop.

The processor110computes the required braking force in response to operation of the brake pedal190or a brake key (not illustrated). Then, the processor11distributes the control signal to the electro-mechanical brake (EMB)170and to at least one of the first to fourth in-wheel modules161to164, thereby correspondingly applying the control signal.

In addition, the processor110can distribute the braking force based on the speed of the vehicle10and the SOC of the battery.

The processor110can check the traveling state of the vehicle10and the SOC of the battery. Correspondingly, the processor110can compute drive force and the braking force that are to be applied to the first to fourth in-wheel modules161to164, respectively, mounted on the vehicle10based on at least one of restricted output values of the battery and can apply the computed drive force and braking force to the first to fourth in-wheel modules161to164.

Accordingly, the in-wheel motors180can operate according to the respectively applied control signals, thereby applying the braking force to the four wheels21to24. In addition, the in-wheel motors180can generate the reverse torque, thereby performing braking.

During braking, the processor110can check whether or not the electro-mechanical brake (EMB)170operates normally and can detect a failure thereof.

In a situation where the electro-mechanical brake (EMB) fails to operate, the processor110can determine whether or not sudden braking is required, and, if necessary, can control braking by redistributing the braking force.

In a case where the electro-mechanical brake (EMB)170fails to operate, the processor110can perform braking by generating the reverse torque through the in-wheel motor180.

In addition, the processor110can recompute and distribute the braking force according to a state of the vehicle10, for example, according to whether or not the speed of the vehicle10, which is measured from the vehicular speed sensor141, decreases or increases. Then, the processor110can apply the control signal to each of the first to fourth in-wheel modules161to164.

In a case where the electro-mechanical brake (EMB)170fails to operate, the processor110can output a warning against a brake failure through a display (not illustrated), such as an instrument panel.

FIG.3is a flowchart illustrating a method of controlling vehicular braking according to a second embodiment of the present disclosure.

As illustrated inFIG.3, the apparatus100for controlling vehicular braking monitors the traveling state of the vehicle10and the SOC of the battery. When a brake-required situation occurs, the apparatus100for controlling vehicular braking controls the vehicle10in such a manner as to reduce the speed thereof and to bring the vehicle10to a stop.

While the vehicle10travels, the processor110receives vehicular speed information from the vehicular speed sensor141(S310), and receives SOC information from the battery management system (BMS)150, thereby monitoring the SOC of the battery (S320).

When a signal is input from the brake pedal190(S330), the processor110computes the required braking force (S340).

The processor110disperses and distributes the braking force to a plurality of the in-wheel motors180and the electro-mechanical brakes (EMB)170based on the required braking force (S350).

The electro-mechanical brakes (EMB)170operate according to the respective distributed braking force, thereby braking the vehicle10. In addition, the in-wheel motors180operate according to the respective distributed braking force and perform barking control in such a manner as to generate the reverse torque.

At this point, the processor110receives, as input, feedback from the electro-mechanical brake (EMB)170, and thus can check a state of the electro-mechanical brake (EMB)170and whether or not to brake the vehicle10.

The processor110determines whether or not the feedback is received from the electro-mechanical brake (EMB)170(S370). In a case where the feedback is received, the processor110maintains the braking by the electro-mechanical brake (EMB)170(S380).

In a case where the feedback is not received, the processor110can determine that a problem occurs with the electro-mechanical brake (EMB)170or that the electro-mechanical brake (EMB)170fails to operate.

In a case where the electro-mechanical brake (EMB)170fails to operate, the processor110determines that a current braking-required situation corresponds to sudden braking (S390).

In a case where the current braking-required situation corresponds to sudden braking, the processor110controls the in-wheel motor180by setting the in-wheel motor180to maximum braking torque (S400). Accordingly, the in-wheel motor180performs braking by maximally generating the reverse torque.

In a case where the current braking-required situation does not correspond to sudden braking, the processor110determines, according to the vehicular speed information being input from the vehicular speed sensor141, whether or not the vehicle10is currently in a speed-reduced state (S410).

In a case where the vehicle10is currently in the speed-reduced state, the processor110keeps the braking torque against the in-wheel motor180at a current value (S420).

In a case where the vehicle10is not currently in the speed-reduced state, the processor110recomputes the braking torque against the in-wheel motor180, thereby correspondingly applying the control signal to the in-wheel motors180(S430).

When a current speed of the vehicle10decreases below a preset value due to a braking control-caused decrease in the speed of the vehicle10(S440), the processor110causes the in-wheel motor180to cancel braking and performs braking by steering the rear wheels23and24in such a manner as to attain a toe-in state (S450).

When the electro-mechanical brake (EMB)170fails to operate, the processor110generates and outputs a warning against this failure, and controls the vehicle10by performing braking in such a manner as to bring the vehicle10to a stop.

The operation of the vehicular braking apparatus100is described in detail as follows.

FIG.4is a flowchart illustrating the flow of data that occurs when the apparatus100for controlling vehicular braking computes the braking force, in the method according to the second embodiment of the present disclosure.

With reference toFIG.4, in a case where the driver operates the brake pedal190, the processor110receives, as input, the speed of the vehicle10(refer to S201), a brake position (the degree of operation) of the brake pedal190(refer to S202), and vehicular data (refer to S203), and computes the required braking force. At this point, the vehicular data (refer to S203) include an acceleration in the vertical direction and the mass of the vehicular10.

The processor110refers to a braking force map MAP based on the speed of the vehicle (refer to S201) and on the brake position (refer to S202), among the data being input (S204), and compares the computed braking force against a mathematical model, which varies with the vehicular data (refer to S203) (S205).

As a result of the comparison, the processor110computes a maximum value MAX from the braking force according to the result of the comparison (S206), and finally determines the required braking force (S207).

The processor110sets a maximum braking force as the required braking force, thereby distributing the braking force.

FIG.5is a flowchart illustrating the flow of data that occurs when the apparatus100for controlling vehicular braking monitors the battery, in the method according to the second embodiment of the present disclosure.

With reference toFIG.5, the processor110receives, as input, the SOC from the battery management system (BMS)150and can determine according to a state of the battery whether or not to perform the braking control using the in-wheel motors180.

The processor110receives, as input, a braking signal resulting from the operation of the brake pedal190(S211) and receives, as input, the SOC of the battery from the battery management system (BMS)150(S212).

The processor110compares the SOC of the battery against a first setting value γ (S213).

In a case where the brake signal is input and where the SOC of the battery is above the first setting value γ (S214), the processor110causes the in-wheel motor180not to be subject to the braking control (S215).

In a case where the SOC of the battery is so sufficient as to be at or above the first setting value γ, the processor110can perform braking using the electro-mechanical brake (EMB)170without the in-wheel motor180being involved.

In a case where the SOC of the battery is below the first setting value γ, the processor110performs the braking control with the in-wheel motor180being involved (S216).

The processor110controls braking by distributing the computed required braking force to the in-wheel motor180and the electro-mechanical brakes (EMB)170.

FIG.6is a flowchart illustrating the flow of data that occurs when the apparatus100for controlling vehicular braking distributes the braking force, in the method according to the second embodiment of the present disclosure.

With reference toFIG.6, the processor110can control braking without using the in-wheel motor180.

The processor110sets a distribution ratio of the required braking force computed inFIG.4, that is, a distribution ratio of the final braking force (refer to S221) on a per-mechanical brake (EMB)170basis and divides the braking force (S222).

The electro-mechanical brakes (EMBs)170are provided in the four wheels21to24, respectively, thereby independently braking the four wheels21to24.

As illustrated inFIG.5, in a case where the SOC of the battery is at or above the first setting value γ, the processor110does not use the in-wheel motor180(S225), and instead, performs braking through the electro-mechanical brake (EMB)170.

The processor110distributes the braking force to the electro-mechanical brakes (EMBs)170provided in the four wheels21to24, respectively, according to the distribution ratio. The processor110applies the control signal in such a manner that the electro-mechanical brakes (EMBs)170individually perform braking.

Accordingly, the electro-mechanical brakes (EMBs)170operate according to the respective received control signal (S223) and apply predetermined braking force to the four wheels21to24, respectively, thereby performing braking (S224).

FIG.7is a flowchart illustrating the flow of data that occurs when the apparatus100for controlling vehicular braking distributes the braking force, with the in-wheel motor180of being involved, in the method according to the second embodiment of the present disclosure.

With reference to7, the processor110can control braking using the in-wheel module160. The processor110can control barking by distributing the braking force to the in-wheel motor180and the electro-mechanical brake (EMB)170.

In a case where the processor110performs braking using the in-wheel motor180according to the SOC of the battery, the processor110computes a T-N (torque vs. RPM) diagram of a motor's nominal torque based on the speed of the vehicle10(refer to S232) and a motor's rotational speed (RPM) (refer to S233) (S234), and checks a motor's possible maximum torque based on the computed diagram (S235). The processor110converts the possible maximum torque into the braking force of the in-wheel motor180.

The processor110compares the previously computed required braking force (refer to S231) and the braking force (the braking force of the in-wheel motor180), which results from the conversion from the possible maximum torque (S236).

In a case where the braking force of the in-wheel motor180is greater than the required braking force, the processor110distributes the required braking force according to a preset distribution ratio 8% (S237). The processor110distributes the braking force, obtained by multiplying the required braking force by the preset distribution ratio 8%, to the in-wheel motor180. The processor110distributes the braking force, obtained by the required braking force by (100—the preset distribution ratio ε %), to the electro-mechanical brake (EMB)170.

For example, when the distribution ratio is 60%, the processor110distributes 60% of the required braking force to the in-wheel motor180and distributes 40% of the required braking force to the electro-mechanical brake (EMB)170, and then can correspondingly perform braking.

Because there is a possibility that the braking by the in-wheel motor180will fail, the processor110may distribute the required braking force to the electro-mechanical brake (EMB)170.

In a case where the braking force of the in-wheel motor180is equal to or smaller than the required braking force, the processor110may distribute the braking force, corresponding to the maximum braking force of the in-wheel motor180, to the in-wheel motor180, and may distribute the braking force obtained by subtracting the maximum braking force from the required braking force to the electro-mechanical brake (EMB)170(S238).

That is, when the maximum braking force of the in-wheel motor180is 70%, the processor110is set to distribute 70% of the required braking force to the in-wheel motor180and to distribute 30% of the required braking force to the electro-mechanical brake (EMB)170, thereby correspondingly performing braking.

Based on the preset distribution ratio and the distribution ratio, which is dependent on the maximum braking force (S239), the processor110switches to control input for the in-wheel motor180and the electro-mechanical brake (EMB)170(S241).

The processor110controls each of the electro-mechanical brakes (EMBs)170according to a designated distribution ratio (S242). In addition, the processor110controls each of the in-wheel motors180according to the designated distribution ratio (S243).

FIG.8is a flowchart illustrating the flow of data that occurs when the apparatus100for controlling vehicular braking determines, through feedback on the braking force, that the brake operates abnormally, in the method according to the second embodiment of the present disclosure.

With reference toFIG.8, when distributing the required braking force and controlling the electro-mechanical brake (EMB)170(S251), the processor110receives the feedback from the electro-mechanical brake (EMB)170and thus checks the braking force (S252).

The vehicle10, capable of independently controlling four wheels, does not have hydraulic stop and connection apparatuses, unlike the existing vehicle. There is a probability that braking will not function normally due to communication and power supply issues. To address this problem, the processor110can verify, through feedback, whether or not braking functions normally.

In a case where an input-to-reception ratio of feedback is lower than a reference setting ratio α % (S253), or in a case where the feedback signal is not received (S254), the processor110determines that the electro-mechanical brake (EMB)170fails to operate (S255).

When it is determined that the electro-mechanical brake (EMB)170operates normally, the processor110maintains exiting control input. When it is determined that the electro-mechanical brake (EMB)170fails to operate, the processor110proceeds to the next step.

FIG.9is a flowchart illustrating the flow of data that occurs when the apparatus100for controlling vehicular braking determines sudden braking, in the method according to the second embodiment of the present disclosure.

With reference toFIG.9, when it is determined that the electro-mechanical brake (EMBs)170fails to operate, the processor110determines whether or not sudden braking is required.

The processor110monitors a brake position (S261).

The processor110compares the brake position with a setting position β. In a case where the brake position is greater than the setting position β (S262), the processor110determines that sudden braking is required (S263).

For example, normal braking is performed when the brake position is at approximately 50%. However, when sudden braking is required, the brake position may be at or above 90%.

When an obstacle is present ahead in the vehicle's traveling or when a traffic light turns red, the driver brings the vehicle10to a sudden stop by operating the brake. In addition, even in a situation where the vehicle10is allowed to come to a slow stop, the driver may operate the brake pedal190to 90%.

Therefore, the processor110can determine a sudden braking-required situation by understanding the driver's intention to perform sudden braking, and thus can control braking. The processor110cannot only determine the position (the degree of operation) of the brake pedal190but can also determine the sudden braking-required situation according to a rate of change per time.

When the sudden braking-required situation is determined, the processor110controls the in-wheel motor180using current possible maximum braking torque of the in-wheel motor180.

FIG.10is a flowchart illustrating the flow of data that occurs when the apparatus100for controlling vehicular braking determines the speed-reduced state, in the method according to the second embodiment of the present disclosure.

With reference toFIG.10, in a state where the electro-mechanical brake (EMB)170fails to operate, in a case where the sudden braking-required situation is not reached, the processor110does not control the in-wheel motor180using maximum available braking torque, and determines in-wheel braking input after determining whether or not the speed of the vehicle10is in the speed-reduced state.

The processor110uses longitudinal acceleration Ax in order to determine whether or not the speed of the vehicle10is in the speed-reduced state.

Based on the longitudinal acceleration Ax (S271), the processor110compares longitudinal acceleration Ax with a second setting value −ξ (S272). At this point, minus longitudinal acceleration Ax represents the speed-reduced state, and plus longitudinal acceleration Ax represents a state of acceleration.

In a case where, as a result of the comparison of the longitudinal acceleration Ax with the second setting value −ξ, the longitudinal acceleration Ax is lower than the second setting value −ξ (S273), the processor110determines that speed reduction is in progress (S274), and maintains in-wheel braking force (S275).

The processor110determines that, in a state where the electro-mechanical brake (EMB)170fails to operate, the braking force acts normally through the in-wheel braking force, and maintains the in-wheel braking force.

In a case where the longitudinal acceleration Ax is higher than the second setting value −ξ (S276), the processor110determines that the braking is insufficient (S277) and recomputes the in-wheel braking force (S280).

In a case where the longitudinal acceleration Ax is higher than 0 (S278), the processor110determines that acceleration is in progress (S279), and recomputes the in-wheel braking force (S280). For example, in a case where the braking force is insufficient while the vehicle10travels on a downhill slope, the vehicle may be in the state of acceleration.

FIG.11is a flowchart illustrating the flow of data occurs when the apparatus for controlling vehicular braking recomputes the in-wheel braking torque, in the method according to the second embodiment of the present disclosure.

With reference toFIG.11, in a case where the braking force is insufficient or where the acceleration is in progress, the processor110determines that current in-wheel braking input does not act on braking, and recomputes the in-wheel braking force.

The processor110can compute a difference between a target speed of the vehicle10(refer to S281) and the current speed of the vehicle10(refer to S282) (S283), can perform PI control based on the difference (S284), and can recompute the in-wheel braking torque (S285).

When the electro-mechanical brake (EMB)170fails to operate, the target speed of the vehicle10is 0.

The processor110can compute the in-wheel braking force based on the difference between the target speed of the vehicle10and the current speed of the vehicle10and can increase the braking force in such a manner that vehicle10reduces the speed thereof.

FIG.12is a flowchart illustrating the flow of data that occurs when the apparatus for controlling vehicular braking performs braking control using the rear wheels23and24, in the method according to the second embodiment of the present disclosure.

With reference toFIG.12, during braking, the processor110monitors a vehicular speed signal that is input from the vehicular speed sensor141(S291).

In a state where the electro-mechanical brake (EMB)170fails to operate, the speed of the vehicle10is reduced by braking the vehicle10using the in-wheel motor180.

When braking reduces the speed of the vehicle10to lower than a first speed o due (S292), the processor110cancels braking that uses the in-wheel motor180(S293). At this point, the first speed may be set to approximately 40 km/h or lower.

In a case where the in-wheel motor180generates the reverse torque, thereby performing braking, it is possible to perform braking until the vehicle comes to a stop. However, in a case where the in-wheel motor180is not precisely controlled in a low-speed section, a situation may occur where the in-wheel braking torque restricts the behavior of the vehicle10.

Accordingly, when the vehicle10enters the low-speed section, the processor110stops braking using the in-wheel motor180.

The processor110applies the control signal to the steering apparatuses of the third and fourth in-wheel modules163and164of the rear wheels23and24, thereby causing the rear wheels23and24to attain the toe-in state. In a case where the rear wheels23and24attain the toe-in state, the braking force can be generated in a low speed of the vehicle10.

The processor110can increase the braking force and can enhance the straight-line traveling using steering angles of the rear wheels23and24by controlling wheel angles of the rear wheels23and24in a toe-in configuration manner. Thus, the processor110can bring the vehicle10to a stop.

At this point, the processor110can control the four wheels21to24in a toe-in configuration manner. However, when performing this toe-in control, the traveling direction of the vehicle10may be limitedly controlled, thereby causing a problem in avoiding an obstacle. For this reason, it is preferred that the rear wheels23and24are controlled in a toe-in configuration manner.

Accordingly, the processor110can increase the braking force and can enhance the straight-line traveling using the steering angles of the rear wheels23and24by controlling the wheel angles of the rear wheels23and24in a toe-in configuration manner. Thus, the processor110can bring the vehicle10to a stop.

When the vehicle10comes to a complete stop, the processor110finishes braking (S295).

Therefore, although the electro-mechanical brake fails to operate in a vehicle capable of independently controlling four wheels, the apparatus for controlling vehicular braking and method according to the first and second embodiment of the present disclosure can effectively perform braking using in the in-wheel motor and can improve the safety of the vehicle.