System and method for controlling recoil in a braking system with an electric brake booster

Abstract

System for controlling recoil in a braking system with an electric brake booster, comprising: a pedal travel sensor (13) that detects a pedal stroke of a brake pedal (10) and transmits the detected pedal stroke to a controller; a battery controller (18) that transmits a current battery voltage to a controller (14); a vehicle speed sensor (17) that transmits the instantaneous vehicle speed information to the controller (14); a first pressure sensing sensor (11) that detects a low hydraulic pressure generated in a first master cylinder (20); a second pressure sensing sensor (12) that detects a high hydraulic pressure generated by driving a working piston (31) of a second master cylinder (30) according to a drive of a motor (37);and a control (14) configured to perform a kickback reduction mode based on the battery voltage information and the vehicle speed information in a state where pedal travel is detected, when a battery voltage is equal to or less than a low-voltage reference value for a threshold time or longer and an instantaneous vehicle speed is equal to or less than a low-speed reference value (Σ).

Description

AREA The present disclosure relates to a system and a method for controlling recoil in a braking system with an electric brake booster. BACKGROUND The statements in this section merely provide background information relating to the present disclosure and may not represent prior art. An electric brake booster braking system is defined as a system that provides a simulated braking feel to a brake pedal when a driver presses the brake pedal, and instead of an existing brake booster, which is a vacuum brake booster using a vacuum from an engine, it performs strong braking through engine driving force and hydraulic pressure. The braking system with electric brake booster is mainly used in a hybrid or electric vehicle that cannot generate a vacuum according to the engine's vacuum pressure, but is also tending to be used in a conventional internal combustion engine to provide rapid braking sensitivity and various additional electronic control functions. The braking system with electric brake booster includes an electric motor to generate braking force. If the electrical energy is not supplied to the motor evenly, a kickback phenomenon can occur due to a difference between the brake hydraulic pressure generated by driving the motor and the hydraulic pressure generated when the driver presses the brake pedal. The kickback phenomenon is a reaction force transmitted to the brake pedal when the driver presses it. Such a kickback phenomenon can cause the driver to experience vibrations, a foreign body sensation, and anxiety during braking. From DE 600 01 031 T2, a system for controlling recoil in a braking system with an electric brake booster is known, comprising: a pedal travel sensor that detects a pedal stroke of a brake pedal (10) and transmits the detected pedal stroke to a controller; a battery controller that transmits a current battery voltage to a controller; a vehicle speed sensor that transmits the instantaneous vehicle speed information to the controller; a first pressure sensing sensor that detects a low hydraulic pressure generated in a first master cylinder; a second pressure sensing sensor that detects a high hydraulic pressure generated by driving a working piston of a second master cylinder (30) according to the driving of a motor. DE 10 2013 214 004 A1 discloses a brake force generator in which a master cylinder generates a first braking force in accordance with an actuating input by an actuating element; with a hydraulic pressure generator which is connected to the master cylinder by a shut-off valve and which generates a second braking force in accordance with the actuating input by the actuating element when the shut-off valve is closed; an abnormality detector which repeatedly determines whether an operating condition of the hydraulic pressure generator is abnormal or not; and a controller which prevents the generation of the second braking force, opens the shut-off valve and transmits the first braking force to the hydraulic pressure generator when the operating condition is abnormal.In the event that the abnormality detector determines that the operating state changes from the abnormal state to the normal state while actuation is being performed with the actuating element, the controller maintains the prevention of the generation of the second braking force and keeps the shut-off valve open until the actuation is completed. The above information disclosed in this section is intended only to improve the understanding of the background of the disclosure and may therefore contain information that does not represent the state of the art already known to the average person skilled in the art. overview The purpose of the present disclosure is to provide a system and a method for controlling kickback in a braking system with an electric brake booster, which is capable of minimizing or reducing a kickback phenomenon in which a kickback force or impact force is transmitted to a brake pedal due to a difference between a high brake hydraulic pressure already generated in a working piston of a second master cylinder by driving a motor and a low brake hydraulic pressure generated in a first master cylinder when a driver presses on a brake pedal, in a kickback situation in which electrical energy is not supplied evenly to the motor due to a low voltage of a battery. The problem is solved by a system for controlling recoil in a braking system with an electric brake booster having the features of claim 1 and a method for controlling recoil in a braking system with an electric brake booster having the features of claim 6. Advantageous embodiments are found in the dependent claims. In one embodiment, the present disclosure provides a system for controlling recoil in a braking system with an electric brake booster, comprising: a pedal travel sensor that senses / detects a pedal stroke of a brake pedal and transmits the sensed pedal stroke to a controller; a battery controller that transmits current battery voltage information to the controller; a vehicle speed sensor that transmits the instantaneous vehicle speed information to the controller; a first pressure sensing sensor that senses a low hydraulic pressure generated in a first master cylinder; a second pressure sensing sensor that senses a high hydraulic pressure generated by driving a working piston of a second master cylinder according to the driving of a motor;and a controller that preferably performs a kickback reduction mode based on battery voltage information and vehicle speed information in a state where pedal travel is detected, when a battery voltage is equal to or less than a low-voltage reference value for a threshold time or longer, and an instantaneous vehicle speed is equal to or less than a low-speed reference value. In a further embodiment, the present disclosure provides a method for controlling recoil in a braking system with an electric brake booster, comprising: detecting a pedal stroke by a pedal travel sensor and transmitting the detected pedal stroke to a controller; transmitting current battery voltage information from a battery controller to a controller; transmitting current vehicle speed information from a vehicle speed sensor to the controller; and preferably executing a recoil reduction mode by the controller when a battery voltage is equal to or less than a low-voltage reference value for a threshold time or longer and an instantaneous vehicle speed is equal to or less than a low-speed reference value, based on the battery voltage information and the vehicle speed information in a state in which the pedal stroke is detected. According to the present disclosure, if the battery voltage is equal to or less than the low-voltage reference value for the threshold time or longer, and the instantaneous vehicle speed is equal to or less than the low-speed reference value, the hydraulic pressure (high brake hydraulic pressure generated in advance in the working piston of the second master cylinder) of the high-pressure section is pre-delivered to the oil reservoir by performing the high-recoil reduction mode of the control system to reduce the difference between the oil pressure of the high-pressure section and the oil pressure of the low-pressure section, so that braking can be easily performed solely by the oil pressure generated in the first master cylinder when the driver presses the brake pedal, and the recoil phenomenon can be prevented or otherwise inhibited or reduced. Further areas of application will become apparent from the description provided herein. It should be understood that the description and examples are intended for illustrative purposes only and are not meant to limit the scope of this disclosure. Brief description of the drawings To facilitate a clear understanding of the disclosure, various exemplary embodiments will now be described with reference to the accompanying drawings. Fig. 1 shows a diagram of a braking system with an electric brake booster, comprising a diagram of a hydraulic circuit in a state where a driver is not pressing a brake pedal; Fig. 2 shows a diagram of the braking system with an electric brake booster, comprising the diagram of the hydraulic circuit in a state where a driver is pressing the brake pedal; Fig. 3 shows a diagram of the braking system with an electric brake booster, comprising the diagram of the hydraulic circuit in a fallback state; Fig. 4 shows a diagram of the braking system with an electric brake booster, comprising the diagram of the hydraulic circuit indicating a situation in which a kickback phenomenon occurs in the fallback state; Fig.Figure 5 shows a diagram of a control configuration of the braking system with an electric brake booster; Figure 6 shows a diagram of the hydraulic circuit, showing a state in which kickback in a braking system with an electric brake booster is prevented; and Figure 7 shows a flowchart, showing a method for preventing kickback in the braking system with an electric brake booster. It should be noted that the drawings shown above are not necessarily to scale and represent a somewhat simplified depiction of various preferred features, intended to illustrate the principles of the disclosure. The specific design features of the present disclosure, as disclosed herein, including, for example, specific dimensions, orientations, installation locations, and shapes, are partly determined by the application specifically designated for this purpose and the working environment. The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION First, a configuration / arrangement and operating sequence of a braking system with an electric brake booster are described to promote understanding of the present disclosure. Fig. 1 shows a diagram of a hydraulic circuit, depicting a braking system with an electric brake booster, and shows a state in which a driver is not pressing on a brake pedal. A first main cylinder 20 is connected to a brake pedal 10. A main piston 21 connected to the brake pedal 10 and an auxiliary piston 22, which is connected to the main piston 21 by a spring 23 and is connected to an inner wall surface in front of the first main cylinder 20 by the spring 23, are installed in the first main cylinder 23. In the first main cylinder 20, the main piston 21 and the auxiliary piston 22 are separated from each other by a first hydraulic chamber 24, and the auxiliary piston 22 and the front inner wall surface of the front inner wall surface of the first main cylinder 20 are separated from each other by a second hydraulic chamber 25. At this point, an oil reservoir 26, in which hydraulic oil is stored to generate hydraulic pressure, is connected to the first and second hydraulic chambers 24 and 25. Furthermore, a pedal simulator is connected to the first hydraulic chamber 24, with a normally closed (NC) simulator valve 16 interposed, and the pedal simulator 15 serves to provide a certain degree of reaction force against the hydraulic pressure generated when a driver presses on a brake pedal, and to simulate a braking feel. On the other hand, in the braking system with electric brake booster, the essential brake hydraulic pressure is generated in the second master cylinder 30, which is operated by driving a motor. A working piston 31 for generating brake hydraulic pressure is provided inside the second master cylinder 30, so that it can be moved forwards and backwards, a hydraulic generating chamber 32 is divided in a space in front of the working piston 31 and the hydraulic generating chamber 32 is supplied with hydraulic oil to generate hydraulic pressure by driving a pump installed in the oil reservoir 26. In particular, a motor 37 is connected to a rear end of the working piston 31 to provide a forward / reverse motion force. In this case, the hydraulic generating chamber 32 of the second main cylinder 30 is connected to a first brake hydraulic supply line 33 and a second brake hydraulic supply line 34 for supplying the brake hydraulic pressure generated by the forward driving force of the working piston 31 during braking. In one embodiment, the first brake hydraulic supply line 33 and the second brake hydraulic supply line 34 are connected to a normally closed (NC) pressure relief valve 35, which allows hydraulic pressure generated by the working piston 31 to flow towards a wheel cylinder, and to a normally closed (NC) balancing valve 36, which is a predetermined throttle valve, that synchronizes the first brake hydraulic supply line 33 and the second brake hydraulic supply line 34 in order to balance the hydraulic pressure flowing in the first brake hydraulic supply line 33 and the hydraulic pressure flowing in the second brake hydraulic supply line 34. The pressure relief valve 35 and the first brake hydraulic supply line 33 are opened according to a control system when the brake hydraulic pressure generated by the working piston 31 is applied to the wheel during braking. Additionally, a first brake hydraulic pressure branch line 41 and a second brake hydraulic branch line 42, each connected to a wheel cylinder of a front right (FR) wheel and a wheel cylinder 52 of a rear left (RL) wheel, are branched off from a distal end of the first brake hydraulic supply line 33, and a third brake hydraulic branch line 43 and a fourth brake hydraulic branch line 44, each connected to a wheel cylinder 53 of a rear right (RR) wheel and a wheel cylinder 54 of a front left (FL) wheel, are branched off from a distal end of the second brake hydraulic supply line 34. At this point, the first to fourth brake hydraulic branch lines 41, 42, 43 and 44 are equipped with a normally open (NO) wheel inlet valve 45 for transmitting brake hydraulic pressure to each wheel cylinder and a normally closed (NC) wheel outlet valve 46, which is opened to release the hydraulic pressure of the wheel cylinder to the oil reservoir. Compared to the fallback situation in which the working piston 31 does not smoothly generate the brake hydraulic pressure through the drive of the motor 37 to supply the wheel with the hydraulic pressure generated in the first master cylinder 20 when the driver presses the brake pedal, a third brake hydraulic supply line 27 is connected between a first hydraulic chamber 24 of the first master cylinder 20 and the first brake hydraulic supply line 33, and a fourth brake hydraulic supply line 28 is connected between a second hydraulic chamber 25 of the first master cylinder 20 and the second brake hydraulic supply line 34. At this point, the third brake hydraulic supply line 27 and the fourth brake hydraulic supply line 28 are each equipped with a normally open (NO) shut-off valve 29 to allow and interrupt the flow of hydraulic pressure. Meanwhile, a position next to the brake pedal 10 is equipped with a pedal travel sensor 13 (PTS) for detecting / sensing a stroke when the driver presses the brake pedal, the third brake hydraulic supply line 27 or the fourth brake hydraulic supply line 28 is equipped with a first pressure sensing sensor 11 for detecting the hydraulic pressure generated in the first master cylinder 20 according to the actuation of the brake pedal by the driver, and the first brake hydraulic supply line 33 or the second brake hydraulic supply line 34 is equipped with the second pressure sensing sensor 12 for detecting the actual brake hydraulic pressure generated by the operation of the working piston 31. As shown in the diagram of the control configuration of Fig. 5, after the controller 14 receives detection signals from the pedal travel sensor 13, the first pressure detection sensor 11 and the second pressure detection sensor 12, the motor 27, the pressure relief valve 35 and the equalizing valve 36, the wheel inlet valve 45, the wheel outlet valve 46, a simulator valve 16, a shut-off valve 29 and the like are controlled to be switched on / off on the basis of the received detection signals. The following describes the operating sequence of the braking system with an electric brake booster. Fig. 2 shows a diagram illustrating the braking system with electric brake booster, including the diagram of the hydraulic circuit in a state where a driver presses the brake pedal. First, when the driver presses the brake pedal 10, the pedal travel sensor 13 detects a pedal stroke at that time and transmits the detected signal to the control unit 14. Subsequently, the controller 14 controls the normally closed (NC) simulator valve 16 in such a way that it can be switched on, so that the simulator valve is switched off. Accordingly, the main piston 21 in the master cylinder connected to the brake pedal 10 is pressed, and the hydraulic oil in the first hydraulic chamber flows through the simulator valve and is transferred to the pedal simulator 15, and the reaction force of a damping element (a rubber damper and a spring) in the pedal simulator 15 is transferred to the brake pedal 10 through the hydraulic oil, so that the driver pressing on the brake pedal 10 feels the braking sensation. At this time, the normally open (NO) shut-off valve 29, which is attached to the third brake hydraulic supply line 27 and the fourth brake hydraulic supply line 28, is switched on by the control signal of the control unit 14 so that it is in a closed state, so that the hydraulic oil present in each hydraulic chamber of the first master cylinder 20 is not transferred to the wheel cylinder. In this way, when the driver presses the brake pedal 10, the braking sensation is simulated and the brake hydraulic pressure, i.e. the brake hydraulic pressure supplied to the wheel cylinder, is essentially generated by the working piston 31 of the second master cylinder 30. More precisely, the motor 37 is driven by the control signal of the control unit 14, and the normally closed (NC) pressure relief valve 35 and the compensating valve 36 are opened. The working piston 31 in the second master cylinder 30 is advanced by the driving of the motor 37, and the hydraulic oil in the hydraulic generating chamber 32 is compressed. The hydraulic pressure (compressed hydraulic oil) flows into the first brake hydraulic supply line 33 and the second brake hydraulic supply line 34, and the hydraulic pressure is diverted to flow into a first to fourth brake hydraulic branch line 41 to 44 and then flows through a wheel inlet valve 45 in the normally open state to be supplied to each wheel cylinder 51 to 54, thereby performing the essential braking. Fig. 3 shows a diagram illustrating the braking system with electric brake booster, and is the diagram of the hydraulic circuit in a fallback state. The fallback situation refers to a situation in which the control of the essential braking force by driving the motor as described above is not smooth or is impossible due to a low voltage condition of the battery that powers the motor, damage to the motor, a leak in the hydraulic line, and the like. If such a fallback situation occurs, braking is effected by the hydraulic pressure generated in the first master cylinder 20 when the driver presses the brake pedal as a fail-safe phase for brake safety. For example, if the controller 14 receives the battery voltage information from the battery controller and detects that the battery is in a low voltage state, the controller 14 determines that the battery is in a fallback state and performs a fallback mode, which is a type of fail-safe mode for brake safety. At this point, when the controller 14 performs the fallback mode, the normally closed (NC) simulator valve 16, the normally open (NO) shut-off valve 29, and the normally closed (NC) pressure relief valve 35 and equalization valve 36 are in a shut-off state as described above, as shown in Table 1 below. [Table 1] [Table 1] Valve name Valve type Before braking (brake ready) Action after braking (valve type) Fallback mode Simulator valve CAUSE OUT Shut-off valve NO OUT Overpressure valve Compensating valve (Cause in / out) Wheel exhaust valve Wheel intake valve NO OFF OFF OFF Furthermore, when the controller 14 performs the fallback mode, the normally open (NO) wheel inlet valve 45 and the normally closed (NC) wheel outlet valve 46 are also switched off, as described in Table 1 above. As shown in Fig. 3, the hydraulic pressure generated in the first master cylinder 20 is supplied to the wheel cylinders of each wheel when the driver presses the brake pedal, so that braking can be carried out. On the other hand, if the fallback situation occurs while the driver is pressing the brake pedal, the control unit 14 will execute the fallback mode from the next braking action. Furthermore, the fallback mode is implemented immediately if a fallback situation occurs, for example, if the battery has an extremely low voltage (if the voltage of an electronic product such as a motor falls below an available voltage or the ECU itself is switched off). However, when the rebound situation occurs and the rebound mode is executed, as shown in Fig. 4, the rebound phenomenon occurs, in which a force is exerted in a reversed direction (a direction opposite to the direction in which the driver applies the brake pedal) due to the difference between the hydraulic pressure (low-pressure section) generated in the first master cylinder 20 and supplied to each of the wheel cylinders 51 to 54, and the hydraulic pressure (high-pressure section) generated in advance by the working piston 31 of the second master cylinder 30 according to the driving of the motor 37 before the rebound mode is executed, and the force due to the rebound phenomenon causes the driver to feel a sensation of difference and fear. The kickback phenomenon can be prevented in low-speed, deceleration / braking and stopping situations where braking of a vehicle in the kickback situation is not strongly influenced by manual braking force (a braking force generated by supplying the hydraulic pressure produced in the first master cylinder 20 to the wheel cylinders of each wheel when the driver presses the brake pedal). This means that in low-speed, deceleration, and stop situations where the vehicle's braking is not only severely impaired by manual braking force in the fallback situation (a braking force generated by supplying the hydraulic pressure produced in the first master cylinder 20 to the wheel cylinders of each wheel when the driver presses the brake pedal), the high hydraulic pressure generated in advance by the working piston can be diverted to the oil reservoir by driving the engine in order to significantly reduce the difference between the hydraulic pressure (low-pressure section) generated in the first master cylinder 20 and supplied to each of the wheel cylinders 51 to 54, and the hydraulic pressure (high-pressure section) generated in advance by the working piston 31 of the second master cylinder 30 according to the driving of the engine 37, before the fallback mode is executed.which reduces the aforementioned backlash phenomenon. The following describes a system and a procedure for controlling a setback in accordance with the present disclosure. Fig. 5 shows a diagram of a control configuration of the brake system with electric brake booster, Fig. 6 shows a diagram of the hydraulic circuit showing a state in which kickback in a brake system with electric brake booster according to the present disclosure is prevented, and Fig. 7 shows a flowchart showing a method for preventing kickback in the brake system with electric brake booster according to the present disclosure. First, when the driver presses the brake pedal to slow the vehicle, the pedal travel sensor 13 detects the pedal stroke (S101). At this time, the control unit 14 receives the detection signal from the pedal travel sensor 13 and receives the current battery voltage information from the battery control unit 18 in real time. Subsequently, the controller 14 detects the battery voltage level based on the battery voltage information transmitted by the battery controller and detects whether the battery voltage is equal to or lower than the low-voltage reference value for the threshold time or longer. Next, if it is determined that the battery voltage is equal to or lower than the low-voltage reference value for the threshold time or longer, the controller 14 receives the detection signal from the vehicle speed sensor 17 to detect the current vehicle speed (S103). At this point, the reason why the control unit 14 detects the instantaneous vehicle speed is to detect the situation (low speed situations, deceleration, stops) in which the braking of the vehicle can only be carried out by the hydraulic pressure generated in the first master cylinder 20 when the driver presses the brake pedal. Accordingly, if the battery voltage in the controller 14 is equal to or lower than the low-voltage reference value for the threshold time or longer, and the instantaneous vehicle speed is equal to or lower than the low-speed reference value α, the backlash reduction mode is executed (S104). Following the execution of the backlash reduction mode by the controller 14, the normally closed (NC) wheel exhaust valve 46 is first activated, so that the wheel exhaust valve 46 is in the open state (S105). Furthermore, the controller 14 controls the normally closed simulator valve 16, the normally open shut-off valve 29, the normally closed pressure relief valve 35, and the normally closed balancing valve 36 such that they can be switched on. [Table 2] [Table 2] Valve Name Valve Type Before Braking (Brake Ready) Action After Braking (Valve Type) Fallback Mode Recoil Reduction Mode Simulator valve NCAUSE IN (Open) Shut-off valve NOAUSEINAUSEIN (Closed) Overpressure valve (open) Balancing valve NCAUSEINAUSEIN (Open) Wheel exhaust valve (open) Wheel intake valve NOAUSAUSAUSAUS (Open) According to the implementation of the backlash reduction mode by the controller 14, as described in the backlash reduction mode in Table 2 above, only the shut-off valve 29 is in the closed state, and the simulator valve 16, the wheel outlet valve 46, the pressure relief valve 35 and the balancing valve 36 are in the open state. Therefore, only the high hydraulic pressure generated in advance by the working piston 31 of the second main cylinder 30 can be delivered to the oil reservoir 26 while being transferred to the wheel cylinder. Accordingly, as shown on the left side of Fig. 6, the high hydraulic pressure generated in advance by the working piston 31 of the second main cylinder 30 is released to the oil reservoir 26 through the pressure relief valve 35, the balancing valve 36, the wheel exhaust valve 46 by driving the motor 37 before the fallback mode is carried out. Next, the controller 14 receives a signal from the first pressure sensing sensor 11, which measures the hydraulic pressure (hydraulic pressure generated in the first main cylinder 20) of the low-pressure section, and the signal from the second pressure sensing sensor 12, which measures the hydraulic pressure (high hydraulic pressure generated in advance by the working piston 31 of the second main cylinder 30) of the high-pressure section, in order to determine whether the difference between the hydraulic pressure of the high-pressure section and the hydraulic pressure of the low-pressure section is reduced so that it is equal to or less than a threshold value β (S106). This means that, since the high hydraulic pressure generated in advance by the working piston 31 of the second main cylinder 30 is delivered to the oil reservoir 26 through the wheel outlet valve 46 by driving the motor 37 before the fallback mode is carried out as described above, the control determines whether the difference between the hydraulic pressure of the high-pressure section and the hydraulic pressure of the low-pressure section is reduced to the point where it is equal to or less than the threshold value β. The threshold value β can be set so that it lies in a range where the kickback does not occur, even when the high hydraulic pressure is transmitted to the brake pedal. Next, if it is determined that the difference between the hydraulic pressure of the high-pressure section and the hydraulic pressure of the low-pressure section is equal to or lower than the threshold, the controller 14 performs the fallback mode (S107). At this point, as described in the fallback mode by performing the fallback mode in Table 2 above by performing the fallback mode of the control 14, the shut-off valve 29, the simulator valve 16, the wheel outlet valve 46, the pressure relief valve 35 and the balancing valve 36 are controlled such that they are switched off, so that only the shut-off valve 29 and the wheel inlet valve 45 are in the open state, and the simulator valve 16, the wheel outlet valve 46, the pressure relief valve 35 and the balancing valve 36 are in the closed state. Accordingly, as shown on the right side of Fig. 6, when the driver presses the brake pedal, the hydraulic pressure generated in the first master cylinder 20 flows through the shut-off valve 29 and the wheel inlet valve 45 to be supplied to the wheel cylinders 51 to 54 of each wheel to decelerate the vehicle, and the hydraulic pressure of the high-pressure section is discharged to the oil reservoir 26 through the wheel outlet valve 46, thus preventing the backfire phenomenon from occurring (S108). As described above, if the battery voltage is equal to or less than the low-voltage reference value for the threshold time or longer, and the instantaneous vehicle speed is equal to or less than the low-speed reference value α, the difference between the hydraulic pressure of the high-pressure section and the hydraulic pressure of the low-pressure section is reduced by performing the kickback reduction mode, so that the vehicle is only slightly decelerated by the hydraulic pressure generated in the first master cylinder 20 when the driver presses the brake pedal in the actual kickback mode, thus preventing the kickback phenomenon from occurring.

Claims

System for controlling recoil in a braking system with an electric brake booster, comprising: a pedal travel sensor (13) that detects a pedal stroke of a brake pedal (10) and transmits the detected pedal stroke to a controller; a battery controller (18) that transmits a current battery voltage to a controller (14); a vehicle speed sensor (17) that transmits the instantaneous vehicle speed information to the controller (14); a first pressure sensing sensor (11) that detects a low hydraulic pressure generated in a first master cylinder (20); a second pressure sensing sensor (12) that detects a high hydraulic pressure generated by driving a working piston (31) of a second master cylinder (30) according to a drive of a motor (37);and a control (14) configured to perform a kickback reduction mode based on the battery voltage information and the vehicle speed information in a state where pedal travel is detected, when a battery voltage is equal to or less than a low-voltage reference value for a threshold time or longer and an instantaneous vehicle speed is equal to or less than a low-speed reference value (α). System according to claim 1, wherein the backlash reduction mode of the control (14) controls a pressure relief valve (35), a balancing valve (36) and a wheel outlet valve (46) such that they are in an open state to release a high hydraulic pressure generated in advance by the working piston (31) of the second main cylinder (30) according to the driving of the motor (37), in order to release the high hydraulic pressure through the wheel outlet valve (46) to an oil reservoir (26). System according to claim 1, wherein a shut-off valve (29) is provided to interrupt the supply of the hydraulic pressure generated in the first main cylinder (20) to the wheel cylinder (51) when the driver presses the brake pedal (10) by performing the backfire reduction mode of the control (14). System according to claim 1, wherein the control (14) is configured to stop the execution of the backfire reduction mode and to perform a fallback mode when a difference between a low hydraulic pressure detected in the first pressure sensing sensor (11) and a high hydraulic pressure detected in the second pressure sensing sensor (12) is reduced to the level equal to or less than a threshold value (β). System according to claim 4, wherein only a shut-off valve (29) and a wheel inlet valve (45) are controlled by the implementation of the fallback mode of the control (14) such that they are in an open state, and a simulator valve (16), a wheel outlet valve (46), a pressure relief valve (35) and a balancing valve (36) are controlled such that they are in a closed state, so that the hydraulic pressure generated in the first master cylinder (20) passes through the shut-off valve (29) and the wheel inlet valve (45) to be supplied to each wheel cylinder (51), thereby braking a vehicle. A method for controlling kickback in a braking system with an electric brake booster, comprising: detecting a pedal stroke by a pedal travel sensor (13) and transmitting the detected pedal stroke to a controller (14); transmitting current battery voltage information from a battery controller (18) to the controller (14); transmitting current vehicle speed information from a vehicle speed sensor (17) to the controller (14); and performing a kickback reduction mode by the controller (14) when a battery voltage is equal to or less than a low-voltage reference value for a threshold time or longer and an instantaneous vehicle speed is equal to or less than a low-speed reference value (α), based on the battery voltage information and the vehicle speed information in a state in which the pedal stroke is detected. The method of claim 6, wherein the backlash reduction mode of the control (14) comprises: controlling a pressure relief valve (35), a balancing valve (36) and a wheel outlet valve (46) such that they are in an open state to release a high hydraulic pressure generated in advance by a working piston of a second main cylinder (30) according to a drive of a motor (37); and directing the high hydraulic pressure through the wheel outlet valve (46) to release the high hydraulic pressure to an oil reservoir (26). Method according to claim 7, wherein a shut-off valve (29) for interrupting the supply of the hydraulic pressure generated in a first main cylinder (20) when a driver presses the brake pedal (10) to the wheel cylinder (51) is controlled after performing the backlash reduction mode of the control (14) such that it is in a closed state. The method of claim 7, wherein the backfire reduction mode of the control (14) further comprises: detecting a low hydraulic pressure generated in a first main cylinder (20) by a first pressure sensing sensor (11); detecting a high hydraulic pressure generated by driving a working piston (31) of a second main cylinder (30) according to a drive of a motor (37) by a second pressure sensing sensor (12); stopping the execution of the backfire reduction mode when a difference between the low hydraulic pressure detected by the first pressure sensing sensor (11) and the high hydraulic pressure detected by the second pressure sensing sensor (12) is reduced such that it is equal to or less than a threshold value; and performing a fallback mode together with stopping the execution of the backfire reduction mode. Method according to claim 9, wherein only a shut-off valve (29) and a wheel inlet valve (45) are controlled such that they are in an open state after performing the fallback mode of the control (14), and a simulator valve (16), a wheel outlet valve (46), a pressure relief valve (35) and a balancing valve (36) are controlled such that they are in a closed state, so that the hydraulic pressure generated in the first master cylinder (20) passes through the shut-off valve (29) and the wheel inlet valve (45) to be supplied to each wheel cylinder (51), thereby braking a vehicle.

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