ELECTRONIC PARKING BRAKE CONTROL DEVICE AND METHOD

Abstract

EPB (electronic parking brake) control device, comprising: a first EPB switch (130) of an EPB; a first controller (110) connected to two terminals among the plurality of terminals (ch1-ch4) of the first EPB switch (130) and configured to calculate a first signal value by combining the signals received from the two terminals and to diagnose the state of the first EPB switch (130) according to the first signal value, and a second controller (120) connected to the other two terminals among the plurality of terminals (ch1-ch4) of the first EPB switch (130) and configured to calculate a second signal value by combining signals received from the two terminals and to diagnose the state of the first EPB switch (130) according to the second signal value, wherein the first controller (110) determines whether the first EPB switch (130), the first controller (110), or the second controller (120) has failed according to the first signal value, and determines the location and cause of the failure to finally diagnose the condition of the first EPB switch (130).

Description

BACKGROUNDREGIONExemplary embodiments of the present disclosure relate to an EPB (Electronic Parking Brake) control device and a method for a vehicle, and more particularly, to an EPB control device and a method that check the state of an EPB system using a signal input from an EPB of a vehicle and can switch the control in the event of a failure so that the vehicle can travel.BACKGROUND EXPLANATIONA self-driving vehicle is generally understood to mean a vehicle which independently and without the assistance of the driver records information from the outside, monitors the environment, determines the road state and drives to the destination.Based on an autonomous driving system installed in the self-driving vehicle, the self-driving vehicle controls a brake to decelerate or stop the vehicle according to the surrounding situation by utilizing the communication inside the vehicle.When emergency braking is required while the vehicle is running in the autonomous driving mode, a main controller transmits a brake signal and controls the brake to stop the vehicle. At this time, when the brake is abnormal, the vehicle may operate an EPB to perform the braking.The EPB can be operated by a simple key operation even when the driver does not manually operate the parking brake, and maintains a parking or holding state of the vehicle by controlling a braking force automatically applied to a wheel to prevent the vehicle from being pushed backward when stopped or started on a hill.The EPB includes an application switch (AS) for activating the EPB and a release switch (RS) for deactivating the EPB.The EPB is activated when the AS is turned on by a driver, and deactivated when the RS is turned on by the driver.The EPB may provide various conveniences to the driver. However, when the EPB is abnormally operated during travel by an abnormal signal or the like, the vehicle may be suddenly braked or turned, and a braking force may not be normally generated.Therefore, in order to check whether the EPB operates in normal operation or to ensure the reliability of the EBP when the AS and the RS operate in normal operation, it is necessary to diagnose a switch failure of the EBP.In the related art, the self-driving vehicle has two controllers to ensure the redundancy of the vehicle controller. Even if an abnormality occurs in a main controller, a sub controller may be used to control the vehicle. Although the vehicle has two controllers, an EPB switch is configured to input a signal to the main controller. Thus, when an abnormality occurs in the main controller, the sub controller cannot control the EPB switch.When the main controller transmits a signal of the EPB switch to the sub controller by communication, the sub controller may receive the signal of the EPB switch, but a problem may occur in signal synchronization. Therefore, there is a limitation in the control of the EPB switch by the sub-controller. DE 10 2013 009 025 A1 discloses an EPB control device having an EPB switch and a controller connected to all four terminals of the EPB switch, wherein the controller determines whether the EPB switch has failed. DE 197 51 431 A1 discloses a further EPB control device in which parallel operating controls are provided. It is therefore an object of the present invention to provide an improved EPB control apparatus and method which avoid the aforementioned problems.The related art of the present disclosure is disclosed in Korean Patent Application KR 10 2010 0 116 782 A entitled "Method for Diagnosing Fault in Electric Brake System",SUMMARYVarious embodiments are directed to an EPB (Electronic Parking Brake) control apparatus and method that can divide and input signals of an EPB into two controllers that combine signals input for the respective terminals to determine whether signals of an EPB switch are normal and determine failure of the controllers or the EPB switch. The invention is defined by the features of claims 1 and 10.In addition, various embodiments are directed to an EPB control apparatus and an EPB method that include two controllers and one or two EPB switches, and perform the control by any controller when the other controller has failed to ensure redundancy.In an embodiment, an EPB control device may include: a first EPB switch of an EPB; a first controller connected to two terminals among the plurality of terminals of the first EPB switch and configured to calculate a first signal value by combining the signals received from the two terminals and diagnose the state of the first EPB switch based on the first signal value; and a second controller connected to the other two terminals among the plurality of terminals of the first EPB switch and configured to calculate a second signal value by combining signals received from the two terminals and diagnose the state of the first EPB switch according to the second signal value. The first controller may determine whether the first EPB switch, the first controller, or the second controller has failed based on the first signal value, and determines the location and cause of the failure to finally diagnose the state of the first EPB switch.The first controller may be connected to a first terminal and a fourth terminal among the plurality of terminals of the first EPB switch, transmit a first state request signal to the first terminal, and transmit a fourth state request signal different from the first state request signal to the fourth terminal, and the second controller may be connected to a second terminal and a third terminal among the plurality of terminals of the first EPB switch, transmit a second state request signal to the second terminal, and transmit a third state request signal different from the second state request signal to the third terminal.When the first EPB switch has failed, the first and second controllers may each determine whether the cause of the failure is an open circuit, a battery short circuit, or a ground fault based on the first or second signal values and determine the location at which the failure occurred between the first and fourth terminals of the first EPB switch.The EPB controller may further include a second EPB switch. The first controller may be connected to a first terminal and a fourth terminal of the second EPB switch, the second controller may be connected to a second terminal and a third terminal of the second EPB switch, and the first and second controllers may respectively calculate the signal value of the signals received from the second EPB switch and diagnose the state of the second EPB switch.In an embodiment, an EPB control method may include: transmitting, by a first controller and a second controller, a state query signal for checking the state of a first EPB switch; calculating, by the first controller, a first signal value by combining signals received from a first terminal and a fourth terminal of the first EPB switch and diagnosing the state of the first EPB switch; calculating, by the second controller, a second signal value by combining signals received from a second terminal and a third terminal of the first EPB switch and diagnosing the state of the first EPB switch; diagnosing, by the first and the second controllers, the state of the first EPB switch based on the second signal value; and determining whether the first EPB switch, the first controller, or the second controller has failed based on the first and second signal values, and determining the location and the cause of the failure to finally diagnose the state of the first EPB switch.The EPB control method may further include: transmitting, by the first and second controllers, a state inquiry signal for checking the state of a second EPB switch; calculating a signal value by combining the signals received from the second EPB switch and diagnosing, by the first and second controllers, the state of the second EPB switch; diagnosing, by the first or second controller, whether the first or second EPB switches have failed; and switching the controller to the second EPB switch to generate a braking force via the second EPB switch when the first EPB switch has failed.The first and second state polling signals may be 1001, and the third and fourth state polling signals may be 0011.Diagnosing the state of the first EPB switch may include determining that the first EPB switch is in a neutral state when the first signal value 3013, determining that the first EPB switch is in an application state when the first signal value 2033 is, and determining that the first EPB switch is in an enable state when the first signal value 3033 is; and determining that the first EPB switch is in the neutral state when the second signal value 2033 is, determining that the first EPB switch is in the application state when the second signal value 3033 is, and determining that the first EPB switch is in the release state when the second signal value 3013 is.The final diagnosing of the state of the first EPB switch may include determining that the failure has been caused by an open circuit in the first or fourth terminal when the first signal value is 2013, and determining that the failure has been caused by an open circuit in the second or third terminal when the second signal value is 2013.The final diagnosing of the state of the first EPB switch may include determining that the failure has been caused by a battery short circuit in the first or fourth terminal when the first signal value is one of the values 3333, 2233, or 3113, and determining that the failure has been caused by a battery short circuit in the second or third terminal when the second signal value is one of the values 3333, 2233, or 3113.The final diagnosing of the state of the first EPB switch may include determining that the failure has been caused by a ground fault in the first or fourth terminal when the first signal value is one of 0000, 0011, or 1001, and determining that the failure has been caused by a ground fault in the second or third terminal when the second signal value is one of 0000, 0011, or 2002.According to the embodiments of the present disclosure, the two controllers may respectively combine the signals received from the EPB switch, and thus easily diagnose failure of the controller or the EPB switch, enabling emergency control of the vehicle.The two controllers may also use different status interrogation signals for the respective ports and receive signals from the EPB switch, thereby improving the identifiability of the signals and enabling the status of the EPB switch to be more accurately determined.In addition, the brake redundancy in the vehicle controller may be ensured by two controllers and at least one EPB switch. Thus, the vehicle can be easily controlled despite failure, whereby accident can be prevented and stability can be improved.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a block diagram briefly illustrating a configuration of an EPB (Electronic Parking Brake) control device according to a first embodiment of the present disclosure. FIG. 2 is a diagram illustrating the configuration of an EPB control device according to a second embodiment of the present disclosure. FIGS. 3A and 3B are diagrams illustrating a configuration of an EPB switch according to an embodiment of the present disclosure. FIGS. 4A to 4C are diagrams for describing the configuration of a circuit formed by a key operation of the EPB switch illustrated in FIG. 3. FIGS. 5A to 5D are graphs illustrating signals of the terminals ch 1 and ch 4 of the EPB switch according to the embodiment of the present disclosure. FIGS. 6A to 6D are graphs illustrating the signals of the terminals ch 2 and ch 3 of the EPB switch according to the embodiment of the present disclosure. FIGS. 7A to 7C are tables showing output signals for the respective causes of failures in the EPB control device according to the embodiment of the present disclosure. FIG. 8 is a flowchart illustrating a failure diagnosis method of an EPB control device according to an embodiment of the present disclosure.DETAILED DESCRIPTION OF THE DEPICTED EMBODIMENTSAs is conventional in the relevant art, some example embodiments may be represented in the drawings in the form of functional blocks, units and / or modules. Those skilled in the art will appreciate that these blocks, units and / or modules are physically implemented by electronic (or optical) circuits such as logic circuits, discrete components, processors, hardwired circuits, memory elements, wiring connections, and the like. When implemented by processors or similar hardware, the blocks, units, and / or modules may be programmed and controlled using software (e.g., code) to perform various functions described herein. Alternatively, each block, unit, and / or module may be implemented by dedicated hardware or as a combination of dedicated hardware for executing some functions and a processor (e.g., one or more programmed processors and associated circuitry) for executing other functions. Each block, unit, and / or module of some example embodiments may be physically divided into two or more interacting and discrete blocks, units, and / or modules without departing from the scope of the inventive concept. Blocks, units, and / or modules of some example embodiments may also be physically combined into more complex blocks, units, and / or modules without being outside the scope of the inventive concept.Hereinafter, an EPB (Electronic Parking Brake) control device and a method will be described with reference to the accompanying drawings according to various exemplary embodiments.It should be appreciated that the drawings are not to scale and the thickness of the lines or the size of the components may be exaggerated for clarity and clarity only. The terms used herein are also defined in consideration of the functions of the invention and may be changed according to the habit or intention of the users or operators. Therefore, the terms should be defined based on the general disclosures set forth herein.FIG. 1 is a block diagram briefly illustrating a configuration of an EPB (Electronic Parking Brake) control device according to a first embodiment of the present disclosure.As illustrated in FIG. 1, the EPB control device according to the first embodiment of the present disclosure includes a first controller 110, a second controller 120, and an EPB switch 130.The EPB controller is connected to an EPB motor 180 and a battery 170 to operate the EPB. The EPB motor 180 is connected to the EPB switch 130 and is operated by an operation of the EPB switch 130, and the battery 170 is configured to supply operating current to the EPB motor 180.The EPB control device is installed in a vehicle further including a steering device, an air conditioner, and components (transmission, battery, and battery management system) depending on a power source (engine). However, the description thereof is omitted here.An EPBS (Electronic Parking Brake System) supplies power from the battery 170 to the EPB motor 180 when the EPB switch 130 is operated, and the EPB motor 180 is driven to operate an EPB actuator (not shown) and generate a braking force. The EPB is activated or deactivated by actuating the EPB switch 130.The EPB switch 130 has a plurality of terminals ch 1 to ch 4. Of the plurality of terminals, two terminals are connected to the first controller 110 and the other two terminals are connected to the second controller 120.For example, the first and fourth terminals ch 1 and ch 4 are connected to the first controller 110, and the second and third terminals ch 2 and ch 3 are connected to the second controller 120. The connections between the ports and the controllers are only an example and may be changed.The first controller 110 functions as a main controller and controls the operation of the components in the vehicle while transmitting data to or receiving data from the respective components via a communication bus.The second controller 120 serves as a sub-controller for assisting the first controller, and monitors the first controller to determine whether the first controller is abnormal. When an abnormality occurs in the first controller or the connection or communication with the first controller is abnormal, the second controller 120 acquires a control authority to control the vehicle and performs a backup operation.Until the ignition is turned off after the vehicle starts, the first and second controllers 110 and 120 periodically transmit a state request signal to the EPB switch 130, and determine whether the EPB switch 130 is normally operated.The first and second controllers 110 and 120 also diagnose a failure not only based on the state of the EPB switch, but also based on the connections between the EPB switch and the controllers or the states of the controllers.The first and second controllers 110 and 120 each apply the state interrogation signal to the EPB switch 130, and then receive signals of the EPB switch 130 corresponding to the state interrogation signal.The first and second controllers 110 and 120 each receive the signals of the EPB switch 130 via the terminals connected to the EPB switch 130, and combine the received signals to determine the state of the controller or the state of the EPB switch 130.The first and second controllers 110 and 120 each calculate the signal value of the signals of the EPB switch 130 by combining the received signals, and determine whether the EPB switch 130 is normally operating based on the calculated signal value.The first and second controllers 110 and 120 check the state of the EPB switch, respectively, and diagnose failure thereof based on the value of the signals received from the EPB switch 130.When it is determined that the signal of the EPB switch 130 is normal, both the first and second controllers 110 and 120 finally determine that the EPB switch 130 is operating normally. When the first or second controller 110 and 120 determines that the signal of the EPB switch 130 is abnormal, the controller determining that the signal of the EPB switch 130 is normal acquires the control authority for controlling the vehicle.The first and second controllers 110 and 120 also determine the application, release, and neutral states of the EPB switch 130 based on the signal of the EPB switch 130, and determine whether the EPB switch 130 is open or short-circuited, thereby diagnosing the cause of a failure in the EPB switch and the location of the terminal where the failure occurred.FIG. 2 is a diagram illustrating the configuration of an EPB control device according to a second embodiment of the present disclosure.As illustrated in FIG. 2, the EPB control device according to the second embodiment of the present disclosure includes a first controller 110, a second controller 120, a first EPB switch 130, and a second EPB switch 140.As described above with reference to FIG. 1, the EPB control device is connected to the battery 170 and the EPB motor 180, and generates a braking force by operating the first or second EPB switches 130 or 140.The same components as described in FIG. 1 are represented by the same reference numerals, and their description is omitted here.The first EPB switch 130 serves as a main switch and supplies battery power to the EPB motor to generate a braking force according to an operation of the switch or a control command of the first or second controller.The second EPB switch 140 functions as an auxiliary switch of the first EPB switch 130.When the controller determines that the first EPB switch 130 has failed, the second EPB switch 140 is operated to generate a braking force instead of the first EPB switch 130.When the first EPB switch 130 has failed, the first or second controller 110 or 120 switches control from the first EPB switch 130 to the second EPB switch 140 such that the second EPB switch 140 applies the operating power of the battery 170 to the EPB motor 180. Thereby, a braking force is generated.The first EPB switch 130 has a plurality of terminals ch 1 to ch 4. Of the plurality of terminals, two terminals are connected to the first controller 110 and the other two terminals are connected to the second controller 120.The second EPB switch 140 has a plurality of terminals ch 1 to ch 4. Of the plurality of terminals, two terminals are connected to the first controller 110 and the other two terminals are connected to the second controller 120.For example, the first and fourth terminals ch 1 and ch 4 of the first EPB switch 130 are connected to the first controller 110, and the second and third terminals ch 2 and ch 3 of the first EPB switch 130 are connected to the second controller 120.In addition, the first and fourth terminals ch 1 and ch 4 of the second EPB switch 140 are connected to the first controller 110, and the second and third terminals ch 2 and ch 3 of the second EPB switch 140 are connected to the second controller 120.The first controller 110 receives the signals of the first and fourth terminals ch 1 and ch 4 of the first EPB switch 130, and receives the signals of the first and fourth terminals ch 1 and ch 4 of the second EPB switch 140.The second controller 120 receives the signals of the second and third terminals ch 2 and ch 3 of the first EPB switch 130, and receives the signals of the second and third terminals ch 2 and ch 3 of the second EPB switch 140.The first and second controllers 110 and 120 check the states of the first and second EPB switches 130 and 140, respectively, and diagnose whether a failure has occurred based on the values of the signals received from the first and second EPB switches 130 and 140.As described above, the first and second controllers 110 and 120 are cross-connected to the first and second EPB switches 130 and 140, so that the terminals of the first and second EPB switches 130 and 140 are second-connected to the first and second controllers 110 and 120, respectively. In this way, the first and second controllers 110 and 120 finally determine the states of the EPB switches based on the signals of the two EPB switches.The first controller 110 may receive four signals from the first and second EPB switches 130 and 140, and the second controller 120 may receive four signals from the first and second EPB switches 130 and 140 to determine the states of the first and second EPB switches based on a total of eight signals. When a failure occurs in one of the EPB switches, the first and second controllers may determine that the signals received from the corresponding EPB switch are abnormal, whereby the failure of the EPB switch can be easily determined.The first and second controllers 110 and 120 each diagnose an abnormality of the controller or a failure of the connection state between the controller and the EPB switches based on the signals received from the first and second EPB switches 130 and 140.For example, if the first controller determines that the signal of the first EPB switch is normal, but the second controller determines that the signal of the first EPB switch is abnormal, it may indicate that the second controller or the connection between the second controller and the first EPB switch is abnormal. The EPB control device according to the second embodiment of the present disclosure includes two controllers, i.e., the first and second controllers 110 and 120, and two switches, i.e., the first and second EPB switches 130 and 140. In the event of failure of control, the EPB control device may switch the control so that the other normal control controls the vehicle. In addition, in the event of failure of one of the EPB switches, the EPB controller may control vehicle braking via the other normal EPB switch. In this way, the EPB control device can control the vehicle even in an emergency situation, for example in the event of a failure.FIGS. 3A and 3B are diagrams illustrating a configuration of an EPB switch according to an embodiment of the present disclosure.As illustrated in FIG. 3A, the EPB switch 130 includes a first button 131, a second button 132, a plurality of terminals ch 1 to ch 4, and a switching circuit 135. The second EPB switch 140 is configured in the same manner, and description thereof is omitted here.The first and second keys of the EPB switch 130 are operated to change the configuration via the internal connections of the switching circuit 135, thereby changing the signals to be output via the plurality of terminals ch 1 to ch 4.The first key 131 applies an application signal to the switching circuit 135, and the second key 132 applies an enable signal to the switching circuit 135.The first and second buttons 131 and 132 are operated by a driver. The first and second buttons 131 and 132 may also be actuated by actuation of a foot brake (not shown) or based on a signal from a vehicle key. For example, the application signal may be applied to the EPB switch 130 when the ignition is turned off or the vehicle key is at a predetermined distance from the vehicle, or the enable signal is applied to the EPB switch 130 when the vehicle key is at a certain location. A parking brake is then activated or deactivated.As illustrated in FIG. 3B, the switching circuit 135 includes a plurality of switches SW 1 to SW 4, a plurality of diodes D 1 to D 4, and the plurality of terminals ch 1 to ch 4 connected to the first or second controller 110 or 120.The first and second keys 131 and 132 apply the application and the release signals to the switching circuit 135, respectively. When the first and second keys 131 and 132 are released, the neutral signal is applied.The first and second buttons 131 and 132 may be configured as a switch. The first and second buttons 131 and 132 may generate signals corresponding to the case that a switch is pulled and the case that the one switch is pressed, or one end and the other end of a switch may function as the first and second buttons, respectively.When the key 131 or the key 132 is operated, the application signal, the enable signal or the neutral signal is input to the switching circuit 135. In response to the input signal, the plurality of switches SW 1 to SW 4 are operated to change the internal circuit configuration. When the circuit configuration of the switching circuit 135 is changed, the signals output via the plurality of terminals ch 1 to ch 4 change.When the application signal is input to the switching circuit 135, the first and third switches SW 1 and SW 3 are operated. When the enable signal is input to the switching circuit 135, the second and fourth switches SW 2 and SW 4 are operated.The first and second controllers 110 and 120 each apply a state interrogation signal to the EPB switch 130 in a predetermined period of time and receive signals in response to the state interrogation signal.The first controller 110 receives the signals of the first and fourth ports ch 1 and ch 4, and the second controller 120 receives the signals of the second and third ports ch 2 and ch 3.When the application signal, the enable signal, and the neutral signal are input to the EPB switch 130, the first and second controllers 110 and 120 compare the signals output via the plurality of terminals with the reference values of the respective signals to diagnose failure of the EPB switch 130.FIGS. 4A to 4C are diagrams for describing the configuration of a circuit formed from a key operation of the EPB switch illustrated in FIGS. 3A and 3B.As illustrated in FIG. 4A, when the neutral signal is input to the switching circuit 135, a first diode D 1 is connected to the first and fourth terminals ch 1 and ch 4, and a third diode D 3 is connected to the second and third terminals ch 2 and ch 3.When the neutral signal is input to the switching circuit 135, the first switch SW 1 connected to the first terminal ch 1 is connected to the second switch SW 2, the second switch SW 2 is connected to the first diode D 1 and connected to the fourth terminal ch 4, the third switch SW 3 connected to the second terminal ch 2 is connected to the fourth switch SW 4, and the fourth switch SW 4 is connected to the third diode D 3 and connected to the third terminal ch 3.As illustrated in FIG. 4B, when the application signal is input to the switching circuit 135, a second diode D 2 is connected to the first and fourth terminals ch 1 and ch 4, and the second and third terminals ch 2 and ch 3 are connected to each other.When the application signal is input to the switching circuit 135, the first switch SW 1 connected to the first terminal ch 1 is connected to the second diode D 2, the second diode D 2 is connected to the fourth terminal ch 4, and the third switch SW 3 connected to the second terminal ch 2 is connected to the third terminal ch 3.As illustrated in FIG. 4C, when the enable signal is input to the switching circuit 135, the first and fourth terminals ch 1 and ch 4 are connected to each other, and a fourth diode D 4 is connected to the second and third terminals ch 2 and ch 3.When the enable signal is input to the switching circuit 135, the first switch SW 1 connected to the first terminal ch 1 is connected to the second switch SW 2, the second switch SW 2 is connected to the fourth terminal ch 4, the third switch SW 3 connected to the second terminal ch 2 is connected to the fourth switch SW 4, and the fourth switch SW 4 is connected to the fourth diode D 4 and connected to the third terminal ch 3.FIGS. 5A to 5D are graphs illustrating the signals of the terminals ch 1 and ch 4 of the EPB switch according to the embodiment of the present disclosure.The following descriptions focus on the first EPB switch 130, and the EPB switch described without the term "first" or "second" may denote the first EPB switch 130 of the first embodiment or the first EPB switch 130 of the second embodiment, and the content of the EPB switch may be applied to the second EPB switch 140 in the same manner.FIG. 5A illustrates the status interrogation signal applied by the first controller 110 to the EPB switch 130, FIG. 5B illustrates an output signal when the EPB switch is in the neutral state, FIG. 5C illustrates an output signal when the EPB switch is in the applied state, and FIG. 5D illustrates an output signal when the EPB switch is in the enable state. The output signals of the EPB switch for the respective terminals are input to the first controller 110.As illustrated in FIG. 5A, the state interrogation signal is applied from the first controller 110 to the first and fourth terminals ch 1 and ch 4 of the EPB switch. The first controller 110 additionally converts 0 and 1 into a signal 10 in the first terminal ch1 and a signal 01 in the fourth terminal ch4 in order to request a status check.Thus, a first status interrogation signal of 1001 is applied to the first terminal ch1 and a fourth status interrogation signal of 0011 is applied to the fourth terminal ch4.When the state inquiry signal is applied to each of the terminals, the EPB switch 130 outputs a signal according to the neutral state, the application state, or the release state.Since the first and fourth terminals of the first and second EPB switches 130 and 140 are connected to the first controller 110, the first and second EPB switches 130 and 140 receive the same status request signals for the respective terminals from the first controller 110. When the first and second EPB switches 130 and 140 are in a normal state, the first and second EPB switches 130 and 140 output the same signals to the first controller 110.As illustrated in FIG. 5B, when a first state request signal 1001 is applied to the first terminal ch 1 and a fourth state request signal 0011 is applied to the fourth terminal ch 4 while the EPB switch is in the neutral state, the circuit described above with reference to FIG. 4A is applied so that the first and second terminals ch 1 and ch 4 output signals via the first diode D 1.When the first state interrogation signal of 1001 is applied to the first terminal ch1 of the EPB switch, 1001 is applied to the fourth terminal ch4 via the first diode D1. In addition, when the fourth state interrogation signal 0011 is applied to the fourth terminal ch4 of the EPB switch, 0000 is applied to the first terminal ch1 via the first diode D1. Thus, the first terminal ch1 outputs 1001 based on 1001 and 0000, and the fourth terminal ch4 outputs 1011 based on 1001 and 0011.The first controller 110 receives 1001 from the first terminal ch 1 of the EPB switch 130 and receives 1011 from the fourth terminal ch 4 of the EPB switch 130. The first controller 110 receives the same signals from the first and second EPB switches 130 and 140.The first controller 110 combines the signals 1001 and 1011 of the first and fourth terminals for the respective digits (digits). Specifically, the first controller 110 combines the 1 of the first terminal and the 1 of the fourth terminal, recognizes the combined number as a binary number 11, and determines the value of the binary number as a signal value 3. In addition, the first controller 110 combines the 0 of the first terminal with the 0 of the fourth terminal, recognizes the combined number as a binary number 00, and determines the value of the binary number as a signal value 0. In addition, the first controller 110 combines the 0 of the first terminal and the 1 of the fourth terminal, recognizes the binary number as the binary number 01, and determines the value of the binary number as the signal value 1. in addition, the first controller 110 combines the 1 of the first terminal and the 1 of the fourth terminal, recognizes the combined number as the binary number 11, and determines the value of the binary number as the signal value 3.When the signal value of 3013 is calculated based on the signals of the first and fourth terminals, the first controller 110 determines that the EPB switch is in the neutral state and operates normally. When the same signals are received from the first and fourth terminals of the first and second EPB switches and the signal value 3013 is calculated, the first controller 110 determines that the two EPB switches are in the neutral state and are operating normally.As illustrated in FIG. 5C, when the first state request signal 1001 is applied to the first terminal ch 1 and the fourth state request signal 0011 is applied to the fourth terminal ch 4 while the EPB switch 130 is in the applied state, the circuit described above with reference to FIG. 4B is applied so that the first and fourth terminals ch 1 and ch 4 output signals via the second diode D 2.When the first state interrogation signal 1001 is applied to the first terminal ch1, 0000 is applied to the fourth terminal ch4 via the second diode D2. In addition, when the fourth state interrogation signal 0011 is applied to the fourth terminal ch4, 0011 is applied to the first terminal ch1 via the second diode D2. Thus, the first terminal ch1 1011 outputs based on 1001 and 0011, and the fourth terminal ch4 outputs 0011 based on 0000 and 0011.The first controller 110 receives 1011 from the first terminal ch 1 of the EPB switch 130, and receives 0011 from the fourth terminal ch 4 of the EPB switch 130. The first controller 110 receives the same signals from the first and second EPB switches 130 and 140.The first controller 110 combines the signals 1011 and 0011 of the first and fourth ports for the respective numerals, and calculates the signal value of the first and fourth ports. The first controller 110 sequentially combines the signal of the first terminal and the signal of the fourth terminal for the respective numerals, recognizes the combined numerals 10, 00, 11 and 11 as binary numbers, calculates the signal values of the respective binary numbers as 2, 0, 3 and 3, and combines the signal values. Thus, the first controller 110 determines that the signal value of the first and fourth terminals is 2033.When the signal value 2033 is calculated based on the signals of the first and fourth terminals, the first controller 110 determines that the EPB switch is in the application state and the signals are normal. When the same signals are received from the first and fourth terminals of the first and second EPB switches and the signal value 2033 is calculated, the controller 110 determines that the two EPB switches are in the application state and are operating normally.As illustrated in FIG. 5D, when the first state interrogation signal of 1001 is applied to the first terminal ch1 and the fourth state interrogation signal of 0011 is applied to the fourth terminal ch4 while the EPB switch 130 is in the enabled state, the circuit described above with reference to FIG. 4C is applied so that the first and fourth terminals ch1 and ch4 output signals.When the first state interrogation signal 1001 is applied to the first terminal ch1, 1001 is applied to the fourth terminal ch4. In addition, when the fourth state interrogation signal 0011 is applied to the fourth terminal ch4, 0011 is applied to the first terminal ch1. That is, the first terminal ch1 outputs 1011 based on 1001 and 0011, and the fourth terminal ch4 outputs 1011 based on 1001 and 0011.The first controller 110 receives 1011 from the first terminal ch 1 of the EPB switch 130 and receives 1011 from the fourth terminal ch 4 of the EPB switch 130. The first controller 110 receives the same signals from the first and second EPB switches 130 and 140.The first controller 110 combines the signals 1011 and 1011 of the first and fourth ports ch 1 and ch 4 for the respective numerals, and calculates the signal value of the first and fourth ports ch 1 and ch 4. The first controller 110 sequentially combines the signal of the first terminal and the signal of the fourth terminal for the respective numerals, recognizes the combined numerals 11, 00, 11 and 11 as binary numbers, calculates the signal values of the respective binary numbers as 3, 0, 3 and 3, and combines the signal values. In this way, the first controller 110 determines that the signal value of the first and fourth terminals is 3033.When the signal value of 3033 is calculated based on the signals of the first and fourth terminals, the first controller 110 determines that the EPB switch is in the enable state and the signals are normal. When the same signals are received from the first and fourth terminals of the first and second EPB switches and the signal value 3033 is calculated, the controller 110 determines that the two EPB switches are in the enabled state and are operating normally.FIGS. 6A to 6D are graphs illustrating the signals of the terminals ch 2 and ch 3 of the EPB switch according to the embodiment of the present disclosure.FIG. 6A illustrates the state interrogation signal applied by the second controller 120 to the EPB switch 130, FIG. 6B illustrates an output signal when the EPB switch is in the neutral state, FIG. 6C illustrates an output signal when the EPB switch is in the applied state, and FIG. 6D illustrates an output signal when the EPB switch is in the enable state. The output signals of the EPB switch for the respective terminals are input to the second controller.As illustrated in FIG. 6A, the state interrogation signal is applied from the second controller 120 to the second and third terminals ch 2 and ch 3 of the EPB switch. The second controller 120 applies a second state request signal 1001 to the second terminal ch2 and applies a third state request signal 0011 to the third terminal ch3.When the state detection signals are applied to the respective terminals, the EPB switch 130 outputs a signal according to the neutral state, the application state, or the release state.Since the second and third terminals of the first and second EPB switches 130 and 140 are connected to the second controller 120, the first and second EPB switches 130 and 140 receive the same status request signals for the respective terminals from the second controller 120. When the first and second EPB switches 130 and 140 are in a normal state, the first and second EPB switches 130 and 140 output the same signals to the second controller 120.As illustrated in FIG. 6B, when the second state request signal 1001 is applied to the second terminal ch 2 and the third state request signal 0011 is applied to the third terminal ch 3 while the EPB switch 130 is in the neutral state, the circuit described above with reference to FIG. 4A is applied so that the second and third terminals ch 2 and ch 3 output the signals via the third diode D 3.When the second state interrogation signal 1001 is applied to the second terminal ch2, 0000 is applied to the third terminal ch3 via the third diode D3. In addition, when the third state interrogation signal 0011 is applied to the third terminal ch3, 0011 is applied to the second terminal ch2 via the third diode D3. That is, the second terminal ch2 outputs 1011 based on 1001 and 0011, and the third terminal ch3 outputs 0011 based on 0000 and 0011.The second controller 120 receives 1011 from the second terminal ch 2 of the EPB switch 130, and 0011 from the third terminal ch 3. The second controller 120 receives the same signals from the first and second EPB switches 130 and 140 in the normal state.The second controller 120 combines the second and third terminal signals 1011 and 0011 for the respective numerals and calculates the signal value of the second and third terminals. The second controller 120 sequentially combines the second terminal signal and the third terminal signal, recognizes the combined numbers 10, 00, 11 and 11 as binary numbers, calculates the signal values of the respective binary numbers as 2, 0, 3 and 3, and combines the signal values. In this way, the second controller 120 determines that the signal value (second signal value) of the second and third terminals is 2033.When the signal value 2033 is calculated based on the signals of the second and third terminals, the second controller 120 determines that the EPB switch is in the neutral state and the signals are normal. When the same signals are received from the second and third terminals of the first and second EPB switches and the signal value 2033 is calculated, the second controller 120 determines that the two EPB switches are in the neutral state and are operating normally.As illustrated in FIG. 6C, when the second state request signal 1001 is applied to the second terminal ch 2 and the third state request signal 0011 is applied to the third terminal ch 3 while the EPB switch 130 is in the application state, the circuit described above with reference to FIG. 4B is applied so that the second and third terminals ch 2 and ch 3 output signals.When the second state interrogation signal 1001 is applied to the second terminal ch2, 1001 is applied to the third terminal ch3. In addition, when the third state interrogation signal 0011 is applied to the third terminal ch3, 0011 is applied to the second terminal ch2. That is, the second terminal ch2 outputs 1011 based on 1001 and 0011, and the third terminal ch3 outputs 1011 based on 1001 and 0011.The second controller 120 receives 1011 from the second terminal ch 2 of the EPB switch 130 and receives 1011 from the third terminal ch 3 of the EPB switch 130. The second controller 120 receives the same signals from the first and second EPB switches 130 and 140 in the normal state.The second controller 120 combines the second and third port signals 1011 and 1011 for the respective digits and calculates the signal value of the second and third ports. The second controller 120 sequentially combines the second terminal signal and the third terminal signal for the respective numerals, recognizes the combined numerals 11, 00, 11 and 11 as binary numbers, calculates the signal values of the respective binary numbers as 3, 0, 3 and 3, and combines the signal values. In this way, the second controller 120 determines that the signal value of the second and third terminals is 3033.When the signal value of 3033 is calculated based on the signals of the second and third terminals, the second controller 120 determines that the EPB switch is in the "on" state and the signals are normal. When the same signals are received from the second and third terminals of the first and second EPB switches and the signal value 3033 is calculated, the second controller 120 determines that the two EPB switches are in the application state and are operating normally.As illustrated in FIG. 6D, when the second state request signal 1001 is applied to the second terminal ch 2 and the third state request signal 0011 is applied to the third terminal ch 3 while the EPB switch 130 is in the enabled state, the circuit described above with reference to FIG. 4C is applied so that the second and third terminals ch 2 and ch 3 output the signals via the fourth diode D 4.When the second state interrogation signal 1001 is applied to the second terminal ch2, 1001 is applied to the third terminal ch3 via the fourth diode D4. In addition, when the third state interrogation signal 0011 is applied to the third terminal ch3, 0000 is applied to the second terminal ch2 via the fourth diode D4. Thus, the second terminal ch2 outputs 1001 based on 1001 and 0000, and the third terminal ch3 outputs 1011 based on 0011 and 1001.The second controller 120 receives 1001 from the second terminal ch 2 of the EPB switch 130 and receives 1011 from the third terminal ch 3 of the EPB switch 130. The second controller 120 receives the same signals from the first and second EPB switches 130 and 140 in the normal state.The second controller 120 combines the second and third terminal signals 1001 and 1011 for the respective digits and calculates the signal value of the second and third terminals. The second controller 120 sequentially combines the second terminal signal and the third terminal signal for the respective digits, recognizes the combined digits 11, 00, 01 and 11 as binary numbers, calculates the signal values 3, 0, 1 and 3 of the respective binary numbers, and combines the signal values. In this way, the second controller 120 determines that the signal value of the second and third terminals is 3013.When the signal value of 3013 is calculated based on the signals of the second and third terminals, the second controller 120 determines that the EPB switch is in the enable state and the signals are normal. When the same signals are received from the second and third terminals of the first and second EPB switches and the signal value of 3013 is calculated, the second controller 120 determines that the two EPB switches are in the enable state and are operating normally.When the first and second controllers each apply a two-digit status interrogation signal to the EPB switch or sequentially apply signals of 1 to the respective terminals of the EPB switch, the first and second controllers cannot detect a failure caused by an open or short circuit of the EPB switch and thus apply a four-digit signal as a status interrogation signal to each terminal of the EPB switch.When the first and second controllers communicate with each other, the first and second controllers may recognize the signals received from the EPB switch as binary numbers and calculate the signal value of the signals, thereby eliminating a problem in signal synchronization.Since the state request signal of the first controller and the state request signal of the second controller are applied to the respective terminals of the EPB switch and the four-digit signals different from each other are applied to the respective terminals, signals corresponding to the four-digit signals are output from the respective terminals of the EPB switch. Therefore, it is possible to accurately determine the state of the EPB switch and distinguish between a failure of the EPB switch and a failure of a controller or a failure of the connection between the controller and the EPB switch.Since the first and fourth terminals of the first and second EPB switches 130 and 140 are connected to the first controller 110, the first controller 110 receives the same signals for the same state polling signals. When the received signals are different from each other, the first controller 110 compares the signal values of the signals to determine the states of the first and second EPB switches 130 and 140.Since the second and third terminals of the first and second EPB switches 130 and 140 are connected to the second controller 120, the second controller 120 receives the same signals for the same state polling signals. When the received signals are different from each other, the second controller 120 compares the signal values of the signals to determine the states of the first and second EPB switches 130 and 140.The first and second controllers 110 and 120 may determine an abnormality of the EPB switch, an abnormality of the controller, and an abnormality between the controller and the EPB switch (abnormality of the communication line) based on the signal value calculated by analyzing the signals received via the respective terminals, and finally determine a failure by communication with each other.For example, if the signal value of the first EPB switch 130 is 3013 and the signal value of the second EPB switch 140 is 2013 while the EPB switches are in the neutral state, the first controller 110 may determine that the second EPB switch has failed. When the signal value of the first EPB switch 130 is 2033 and the signal value of the second EPB switch 140 is 2013 while the EPB switches are in the neutral state, the second controller 120 may determine that the second EPB switch has failed. In this way, the first controller 110 and the second controller 120 finally determine, based on the signal values, that the first EPB switch is in the neutral state and the second EPB switch 140 has failed.In addition, when the signal value of the first EPB switch 130 is 2033 and the signal value of the second EPB switch 140 is 2033, the first controller 110 determines that the first EPB switch 130 is in the application state and the signals are normal. When the signal value of the first EPB switch 130 is 2033 and the signal value of the second EPB switch 140 is 3013, the second controller 120 determines that the signals are abnormal and the second controller has failed.In this way, the first controller 110 finally determines that the second controller 120 is abnormal or the connection between the second controller and the EPB switch is abnormal (communication line abnormality).FIGS. 7A to 7C are tables showing output signals for the respective causes of failures in the EPB control device according to the embodiment of the present disclosure.As illustrated in FIGS. 7A to 7C, the first and second controllers 110 and 120 each calculate the signal value of the signals received from the EPB switch and determine whether the EPB switch has failed.As illustrated in FIG. 7A, the first and second controllers 110 and 120 each determine whether a communication line is disconnected or a failure has been caused by an open circuit of the circuit of the EPB switch based on the signal value received from the EPB switch.If the EPB switch has failed due to an open circuit, the signal value of the signals input to the controller is calculated as 2013, regardless of whether the EPB switch is in the neutral state, the application state, or the release state.Since the signal value 2013 is not generated while the EPB switch is in the normal state, the first and second controllers 110 and 120 determine that the EPB switch having the signal value 2013 has failed due to an open circuit.When one of the signal values of the signals received from the plurality of terminals of the first EPB switch 130 is 2013, the first and second controllers 110 and 120 may also determine that the corresponding terminal or the communication line connected to the corresponding terminal is disconnected and determine the location of the failure.For example, when the signal value of the signals of the first and fourth terminals ch 1 and ch 4 input from the first EPB switch is 2013 and the signal value of the signals of the second and third terminals ch 2 and ch 3 input from the first EPB switch is 2033, the first controller 110 may determine that the first EPB switch is in the neutral state and a failure has been caused by an open circuit in the first or fourth terminals.Since the signal value is calculated as 2013 regardless of the state of the EPB switch and the open circuit location, the first controller 110 may determine that a failure due to the open circuit has occurred in the terminal receiving the signal having the signal value 2013.As illustrated in FIG. 7B, the first and second controllers 110 and 120 may determine whether a failure has been caused by a short circuit of the battery.When a battery short circuit occurs at the first terminal ch 1, the first EPB switch 130 outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 2233 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the release state.When a battery short circuit occurs at the fourth terminal ch 4, the first EPB switch 130 outputs a signal having a signal value of 3113 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the release state.When a battery short circuit occurs at the second terminal ch 2, the first EPB switch 130 outputs a signal having a signal value of 2233 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the release state.When a battery short circuit occurs at the third terminal ch 3, the first EPB switch 130 outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 3333 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 3113 when the first EPB switch 130 is in the release state.When the signal value of the signals of the first and fourth terminals of the first EPB switch 130 is 3113, the first controller 110 determines that the failure has been caused by the short circuit of the battery in the fourth terminal of the first EPB switch 130.When the signal value of the signals of the first and fourth terminals of the first EPB switch 130 is 3333, the first controller 110 determines which terminal the failure has occurred based on the determination result for the second EPB switch received from the second controller 120.When the signal value of the signals received from the second and third terminals of the first EPB switch 130 is 3033, the second controller 120 transmits the signal value to the first controller.In response to the signal value received from the second controller, the first controller determines that the first EPB switch 130 is in the engaged state and a failure has been caused by a battery short circuit in the fourth terminal.When the signal value of the first and fourth terminals is 2233 while the first EPB switch is in the application state, the first controller may determine that a failure has been caused by a battery short circuit in the first terminal.As illustrated in FIG. 7C, the first and second controllers 110 and 120 may determine whether a failure has been caused by a ground fault.When a ground fault has occurred in the first terminal ch 1, the first EPB switch 130 outputs a signal having a signal value of 0011 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the release state.When a battery short circuit has occurred in the fourth terminal ch 4, the first EPB switch 130 outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 1001 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the release state.When a ground fault has occurred in the second terminal ch 2, the first EPB switch 130 outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 0011 when the first EPB switch 130 is in the release state.When a ground fault has occurred in the third terminal ch 3, the first EPB switch 130 outputs a signal having a signal value of 2002 when the first EPB switch 130 is in the neutral state, outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the application state, or outputs a signal having a signal value of 0000 when the first EPB switch 130 is in the release state.When the signal value of the signals of the second and third terminals of the first EPB switch 130 is 0011, the second controller 120 determines that a failure has been caused by a ground fault in the second terminal of the first EPB switch 130.When the signal value of the signals of the second and third terminals of the second EPB switch 140 is 2002, the second controller 120 determines that a failure has been caused by a ground fault in the third terminal of the second EPB switch 140.When the signal value of the signals of the second and third terminals of the first EPB switch 130 is 0000, the second controller 120 determines in which terminal a failure has occurred based on the determination result of the first controller. When the first controller 110 determines that the first EPB switch is in the neutral state, the second controller 120 determines that a failure has been caused by a ground fault in the second terminal of the first EPB switch 130.In this way, the first and second controllers 110 and 120 may identify not only the EPB switch at which the failure occurred, but also the location of the terminal at which the failure occurred in the corresponding EPB switch and the cause of the failure.The first and second controllers 110 and 120 each diagnose a failure of the EPB switch 130, and determine an abnormality of the communication line between the EPB switch 130 and the corresponding controller or an abnormality of the controller.The first controller 110 and the second controller 120 may each adopt a control authority from a controller in which a failure has been determined and perform an emergency control. The first controller 110 and the second controller 120 may also change control over the EPB switch where a failure has been determined.For example, when the signal value of the first controller 110 is abnormal, the second controller 120 determines that the first controller has failed and obtains the control authority to start a backup operation by emergency control.When it is determined that the first EPB switch 130 has failed, the first controller 110 switches the control to the second EPB switch 140 to maintain the driving operation.The second controller 120 may issue a warning to indicate that the emergency control is performed while the driving state is maintained by the emergency control. The second controller may issue a warning in the form of a warning light, a warning sound, or a warning message.FIG. 8 is a flowchart illustrating a failure diagnosis method of an EPB control device according to an embodiment of the present disclosure.As illustrated in FIG. 8, the first controller 110 controls the operation of the components of the vehicle when the ignition switch is turned on to start the vehicle while communicating with the components. The second controller 120 supports the first controller 110 and monitors the state of the first controller 110.The first controller 110 is connected to the first terminal and the fourth terminal ch 1 and ch 4 of the EPB switch 130, and the second controller 120 is connected to the second and the third terminal ch 2 and ch 3 of the EPB switch 130. The first and second controllers 110 and 120 each transmit a state interrogation signal for requesting a state check in a predetermined period of time in step S310.From the ignition switch being turned on to the ignition switch being turned off after the vehicle is turned off, the first and second controllers 110 and 120 may check the state of the EPB switch 130 in the predetermined period of time.As described above with reference to FIGS. 5A and 6A, the first and second controllers each transmit the status request signal to the EPB switch. The first controller 110 transmits 1001 to the first terminal of the EPB switch and transmits 0011 to the fourth terminal of the EPB switch, and the second controller 120 transmits 1001 to the second terminal of the EPB switch and transmits 0011 to the third terminal of the EPB switch. When there are two EPB switches, the first controller 110 transmits the state interrogation signal to the first and fourth terminals of the first and second EPB switches 130 and 140, and the second controller 120 transmits the state interrogation signal to the second and third terminals of the first and second EPB switches 130 and 140.In response to the status request signals received from the controllers, the EPB switch outputs a signal to the first and second controllers through the plurality of terminals (first to fourth terminals ch1 to ch4). Thus, the first controller 110 receives the signals from the first and fourth terminals ch 1 and ch 4 of the EPB switch 130, and the second controller 120 is connected to the second and third terminals ch 2 and ch 3 and receives the signals in step S 320.The first and second controllers 110 and 120 analyze the received signals, combine the analyzed signals for the respective terminals, and calculate the signal value of the combined signals to analyze the state of the EPB switch in step S 330.The first and second controllers 110 and 120 determine whether the signals are normal from the signal value of the EPB switch in steps S 340 and S 380. As described in FIGS. 5 to 7, the first and second controllers 110 and 120 calculate the signal value by combining the signals of the EPB switch and determine whether the signals are normal.Based on the signals of the EPB switch, the first and second controllers 110 and 120 each determine the state of the EPB switch according to the signal value of the signals, and determine whether the EPB switch or the controller has failed and the communication line between the EPB switch and the corresponding controller is abnormal.FIG. 8 discloses that the second controller performs the signal determination after the first controller performs the signal determination. However, the present disclosure is not limited thereto, but the first and second controls may perform the signal determination simultaneously, and the order of the signal determination may be changed.When the signal is normal, the first controller 110 continues traveling (normal operation) in step S 370. If the signal is abnormal or the EPB switch or the controller has failed, the first controller 110 outputs a warning in step S350. The warning is output in the form of at least one warning light, a warning message, a warning tone or a warning voice.When it is determined that one of the controllers has failed, the first controller 110 switches the controller and performs emergency control (step S 360).When the determination result of step S 380 indicates that the signal is normal, the second controller 120 maintains the operation (normal operation). When the determination result of step S 380 indicates that the signal is abnormal or the EPB switch or the corresponding controller has failed, the second controller 120 outputs a warning in step S 390.When it is determined that one of the controllers has failed, the second controller 120 may switch the controller and perform an emergency control.During the emergency control, the vehicle is controlled by the normal control, but the warning is maintained because it is difficult to monitor the state of the corresponding control and perform a backup operation.The first and second controllers 110 and 120 transmit / receive information on the signal of the EPB switch to / from each other and finally determine the state of the EPB switch, respectively, in step S 400.For example, if the signal value of the signals of the second and third terminals of the first EPB switch 130 is 0000, there are a plurality of failure locations or causes of failure for the signal value 0000. Therefore, the second controller 120 receives the information of the first controller and finally determines the port in which the failure has occurred based on the determination result.When it is determined that the EPB switch is abnormal, the first or second controller 110 or 120 outputs a warning in step S 420.When it is determined that the EPB switch has failed when only one EPB switch is present, the first controller 110 may maintain the travel by controlling the vehicle via the emergency control. In some cases, the first controller controls the vehicle that needs to be stopped urgent.When the first EPB switch 130 and the second EPB switch 140 are present, the first controller 110 identifies an abnormal EPB switch and switches the control to a normal EPB switch in step S 440.The first controller 110 switches the controller via the EPBT switch or the corresponding controller and controls the operation of the vehicle.In this way, the vehicle can continuously check the state of the EPB switch and diagnose not only an abnormality of the controller or the communication line between the controller and the EPB switch, but also the location and the cause of a failure of the EPB switch. The vehicle may also be subjected to emergency control in the event of an abnormality occurring through the control switch between the two controllers or the EPB switches, which makes it possible to perform a substitute operation during the preparation for an accident.Although exemplary embodiments of the disclosure have been disclosed for illustrative purposes, those skilled in the art will appreciate that various changes, additions and substitutions are possible, without departing from the scope and spirit of the disclosure as defined in the appended claims. The true technical scope of the disclosure should therefore be defined by the following claims.

Claims

EPB control device (electronic parking brake) comprising: a first EPB switch (130) of an EPB; a first controller (110) connected to two terminals among the plurality of terminals (ch1-ch4) of the first EPB switch (130) and configured to calculate a first signal value by combining the signals received from the two terminals and diagnose the state of the first EPB switch (130) according to the first signal value; and a second controller (120) connected to the other two terminals among the plurality of terminals (ch1-ch4) of the first EPB switch (130) and configured to calculate a second signal value by combining signals received from the two terminals, Diagnosing the state of the first EPB switch (130) according to the second signal value, wherein the first controller (110) determines according to the first signal value whether the first EPB switch (130), the first controller (110), or the second controller (120) has failed, and determines the location and cause of the failure to finally diagnose the state of the first EPB switch (130).The EPB control device according to claim 1, wherein the first controller (110) is connected to a first terminal (ch1) and a fourth terminal (ch4) among the plurality of terminals (ch1-ch4) of the first EPB switch (130), transmits a first state request signal to the first terminal (ch1), and transmits a fourth state request signal different from the first state request signal to the fourth terminal (ch4), and the second controller (120) is connected to a second terminal (ch2) and a third terminal (ch3) among the plurality of terminals (ch1-ch4) of the first EPB switch (130), transmits a second state request signal to the second terminal (ch2), and transmits a third state request signal different from the second state request signal to the third terminal (ch3).The EPB control device according to claim 1, wherein the first controller (110) calculates the first signal value for the first and fourth terminals (ch1, ch4) by combining the signals of the first and fourth terminals (ch1, ch4) among the plurality of terminals (ch1-ch4) of the first EPB switch (130) for the respective digits (digit), and the second controller (110) calculates the second signal value for the second and third terminals (ch2, ch3) by combining the signals of the second and third terminals (ch2, ch3) among the plurality of terminals (ch1-ch4) of the first EPB switch (130) for the respective digits (digit).The EPB controller of claim 1, wherein the first and second controllers (110, 120) each determine which state the first EPB switch (130) is in, namely, either a neutral state, an apply state, or a release state, based on the first or second signal values.The EPB control device according to claim 1, wherein when the first EPB switch (130) has failed, the first and second controllers (110, 120) each determine whether the cause of the failure is an open circuit, a battery short circuit, or a ground circuit based on the first or second signal values, and determine the location where the failure occurred among the first to fourth terminals of the first EPB switch (130).The EPB controller of claim 1, wherein the first controller (110) receives information about the second signal value and the combined signals from the second controller (120), and finally diagnoses the state of the first EPB switch (130).The EPB control device according to claim 1, wherein the second controller (120) performs a backup operation by emergency control when the first controller (110) is abnormal.The EPB control device according to claim 1, further comprising a second EPB switch (140), wherein the first controller (110) is connected to a first terminal (ch1) and a fourth terminal (ch4) of the second EPB switch (140), the second controller (120) is connected to a second terminal (ch2) and a third terminal (ch3) of the second EPB switch (140), and the first and second controllers (110, 120) each calculate the signal value of the signals received from the second EPB switch (140) and diagnose the state of the second EPB switch (140).The EPB control device according to claim 8, wherein the first controller (110) diagnoses whether the first or second EPB switches (130, 140) have failed based on the signal value of the signals received from the first and second EPB switches (130, 140), and switches the controller to a normal EPB switch to generate a braking force.AN EPB control method, comprising: transmitting, by a first controller (110) and a second controller (120), a state inquiry signal for checking the state of a first EPB switch (120); calculating, by the first controller (110), a first signal value by combining signals received from a first terminal (ch1) and a fourth terminal (ch4) of the first EPB switch (130) and diagnosing the state of the first EPB switch (130); calculating, by the second controller (120), a second signal value by combining signals received from a second terminal (ch2) and a third terminal (ch3) of the first EPB switch (130) and diagnosing the state of the first EPB switch (130); diagnosing the state of the first EPB switch (130) based on the second signal value by the first and second controllers (110, 120), respectively; and determining whether the first EPB switch (130), the first controller (110), or the second controller (120) has failed based on the first and second signal values, and determining the location and the cause of the failure to finally diagnose the state of the first EPB switch (130).The EPB control method according to claim 10, wherein the transmitting the state polling signal comprises: transmitting, by the first controller (110), a first state polling signal to the first terminal (ch1) and transmitting, to the fourth terminal (ch4), a fourth state polling signal different from the first state polling signal, and transmitting, by the second controller (120), a second state polling signal to the second terminal (ch2) and transmitting, to the third terminal (ch3), a third state polling signal different from the second state polling signal.The EPB control method according to claim 10, wherein the first signal value is a signal value for the first and fourth terminals (ch1, ch4) calculated by combining the signal of the first terminal (ch1) and the signal of the fourth terminal (ch4) for the respective digits (digit), and the second signal value is a signal value for the second and third terminals (ch2, ch3) calculated by combining the signal of the second terminal (ch2) and the signal of the third terminal (ch3) for the respective digits (digit).The EPB control method of claim 10, wherein diagnosing the state of the first EPB switch (130) comprises determining which state the first EPB switch (130) is in, namely, one of a neutral state, an application state, and an enable state, based on the first and second signal values.The EPB control method according to claim 10, wherein the finally determining the state of the first EPB switch (130) when the first EPB switch (130) has failed comprises determining whether the cause of the failure is an open circuit, a battery short circuit, or a ground circuit based on the first or the second signal value and determining the location where the failure occurred among the first to fourth terminals (ch1-ch4) of the first EPB switch (130).The EPB control method of claim 10, further comprising: transmitting a state query signal for checking the state of a second EPB switch (140) by the first and second controllers (110, 120), respectively; calculating a signal value by the first and second controllers (110, 120), respectively, by combining the signals received from the second EPB switch (140) and diagnosing the state of the second EPB switch (140); diagnosing, by the first or second controller (110, 120), whether the first or second EPB switch (140) has failed; and switching the controller to the second EPB switch (140) to generate a braking force via the second EPB switch (140) when the first EPB switch (130) has failed.The EPB control method according to claim 11, wherein the first and second state polling signals 1001 and the third and fourth state polling signals are 0011.The EPB control method of claim 13, wherein diagnosing the state of the first EPB switch (130) comprises determining that the first EPB switch (130) is in a neutral state when the first signal value 3013, determining that the first EPB switch (130) is in an application state when the first signal value 2033 is, and determining that the first EPB switch (130) is in an enable state when the first signal value 3033 is; and determining that the first EPB switch (130) is in the neutral state when the second signal value 2033 is, determining that the first EPB switch (130) is in the application state when the second signal value 3033 is, and determining that the first EPB switch (130) is in the release state when the second signal value 3013 is.The EPB control method according to claim 14, wherein the finally diagnosing the state of the first EPB switch (130) comprises determining that the failure has been caused by an open circuit in the first or fourth terminal (ch1, ch4) when the first signal value is 2013, and determining that the failure has been caused by an open circuit in the second or third terminal (ch2, ch3) when the second signal value is 2013.The EPB control method according to claim 14, wherein the finally diagnosing the state of the first EPB switch (130) comprises determining that the failure has been caused by a battery short circuit in the first or the fourth terminal (ch1, ch4) when the first signal value is one of the values 3333, 2233, or 3113, and determining that the failure has been caused by a battery short circuit in the second or the third terminal (ch2, ch3) when the second signal value is one of the values 3333, 2233, or 3113.The EPB control method according to claim 14, wherein the finally diagnosing the state of the first EPB switch (130) comprises determining that the failure has been caused by a ground fault in the first or fourth terminal (ch1, ch4) when the first signal value is one of 0000, 0011 or 1001, and determining that the failure has been caused by a ground fault in the second or third terminal (ch2, ch3) when the second signal value is one of 0000, 0011 or 2002.

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