Electro-mechanical brake system and controlling method thereof

Abstract

An electric brake system and a method for controlling the same are disclosed. An electric brake system according to the present embodiment includes a driving unit comprising a motor that generates a driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor; a sensor unit comprising a first sensor that outputs a signal corresponding to the operating distance of the motor, a second sensor that outputs a signal corresponding to a force applied from the disc to the brake pad, and a third sensor that outputs a signal corresponding to an active braking condition of the vehicle; and a control unit that estimates and updates a contact point between the disc and the brake pad whenever braking or release of the brake pad occurs based on a signal received from the sensor unit, wherein the control unit is provided to adjust the distance between the disc and the brake pad based on the estimated and updated contact point.

Description

Technology Field

[0001] The present invention relates to an electric brake system and a control method thereof, and more specifically, to an electric brake system and a control method thereof capable of preventing drag phenomena while simultaneously improving braking responsiveness. Background Technology

[0002] Vehicles are essentially equipped with a braking system to perform braking, and various types of braking systems are being proposed for the safety of drivers and passengers.

[0003] Conventional braking systems primarily utilized a method in which, when the driver pressed the brake pedal, a mechanically connected booster supplied the hydraulic pressure required for braking to the wheel cylinders.

[0004] However, in recent years, Electro-Mechanical Brakes (EMBs) have been developed and are widely used as next-generation brake systems. These brakes receive the driver's braking intent via electrical signals and, based on this, operate electric devices such as motors to provide braking force to the vehicle.

[0005] This electric braking system does not require hydraulic pressure delivery time and enables optimal control of vehicle braking force, resulting in a relatively short braking distance that significantly enhances driver safety. Furthermore, due to electronic braking, it offers the advantage of making brake pedal use very easy and completely eliminating vibration or braking noise.

[0006] However, in such electric brake systems, after generating braking force through the frictional force produced by the contact between the disc and the brake pad, there are cases where the brake pad does not fully return to its original position due to the return spring, etc., resulting in a drag phenomenon where mutual friction occurs between the disc and the brake pad even when not braking.

[0007] This drag phenomenon causes unnecessary friction between the disc and the brake pad, resulting in problems such as loss of engine power and reduced fuel efficiency, generation of abnormal vibration known as judder which degrades interior quietness and ride comfort, and shortened brake pad life.

[0008] Meanwhile, in order to prevent such drag phenomena, if a sufficient gap is secured between the brake pad and the disc, there is a problem in that the ineffective stroke increases when the vehicle is braking in similar situations, thereby reducing braking responsiveness. Prior art literature

[0009] Korean Patent Publication No. 10-1220294 (Published on April 23, 2003) The problem to be solved

[0010] The present embodiment aims to provide an electric brake system capable of achieving zero drag by preventing drag caused by the gap between the brake pad and the disc, and a control method thereof.

[0011] The present embodiment aims to provide an electric brake system and a control method thereof that can prevent drag phenomena and reduced responsiveness of the brake caused by wear of the brake pads, etc.

[0012] The present embodiment aims to provide an electric brake system and a control method thereof that can prevent a decrease in brake responsiveness by adjusting the gap between the disc and the brake pad when an active braking condition occurs.

[0013] The present embodiment aims to provide an electric brake system and a control method thereof that can prevent adverse effects such as a rise in disc temperature, the occurrence of drag, and a shortened lifespan of the brake pad caused by the gap between the disc and the brake pad that is adjusted when active braking conditions occur. means of solving the problem

[0014] According to one embodiment of the present invention, an electric brake system is provided, comprising: a driving unit including a motor that generates a driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor; a sensor unit including a first sensor for measuring the operating distance of the motor, a second sensor for measuring or estimating a force applied from the disc to the brake pad, and a third sensor for detecting an active braking condition of the vehicle; and a control unit that estimates and updates a contact point between the disc and the brake pad whenever a braking input or release of a braking input occurs, and adjusts the distance between the disc and the brake pad based on the contact point according to information measured and detected by the sensor unit.

[0015] The control unit estimates the point at which the force begins to increase according to the operating distance of the motor due to the braking input, or the point at which the force becomes 0 according to the operating distance of the motor due to the release of the braking input, as the contact point.

[0016] When power is applied to the motor or the braking input is released, the control unit moves the brake pad by a first operating distance that is preset based on the contact point, and the first operating distance can be set to the shortest distance where no drag phenomenon occurs between the brake pad and the disc.

[0017] In addition, the control unit moves the brake pad by a preset second operating distance relative to the contact point when an active braking condition of the vehicle occurs, and the second operating distance may be set to be closer than the first operating distance from the contact point.

[0018] At this time, the control unit moves the brake pad by the first operating distance when the braking input is released while the brake pad has been moved by the second operating distance.

[0019] In addition, the control unit moves the brake pad by the first operating distance when there is no braking input for a preset time while the brake pad is moved by the second operating distance.

[0020] In addition, the operating distance of the motor can be defined as the travel distance of the brake pad according to the driving of the motor.

[0021] In addition, braking input and release of braking input can be provided by the driver's operation of the brake pedal.

[0022] Meanwhile, according to another embodiment of the present invention, an electric brake system is provided that includes a driving unit comprising a motor that generates a driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor, and a control unit that adjusts the distance between the disc and the brake pad through the driving of the motor, wherein the control unit estimates and updates a contact point between the disc and the brake pad whenever a braking input or a braking input release occurs, moves the brake pad from the disc by a preset first operating distance based on the contact point when power is applied to the motor or when the braking input is released, and moves the brake pad from the disc by a preset second operating distance based on the contact point when an active braking condition of the vehicle occurs.

[0023] Here, the contact point determination unit estimates the point at which the force begins to increase according to the operating distance of the motor due to the braking input, or the point at which the force becomes 0 according to the operating distance of the motor due to the release of the braking input, as the contact point.

[0024] In addition, the first operating distance can be set to the shortest distance where no drag phenomenon occurs between the brake pad and the disc.

[0025] In addition, the second operating distance may be set closer to the contact point than the first operating distance.

[0026] In addition, when the braking input is released, the drive control unit moves the brake pad, which has been moved by the second operating distance from the disc based on the contact point, by the first operating distance based on the contact point.

[0027] In addition, when there is no braking input for a preset time, the drive control unit moves the brake pad, which has been moved by the second operating distance from the disc relative to the contact point, by the first operating distance relative to the contact point.

[0028] At this time, the operating distance of the motor can be defined as the travel distance of the brake pad according to the driving of the motor.

[0029] In addition, braking input and release of braking input can be provided by the driver's operation of the brake pedal.

[0030] Meanwhile, according to another embodiment of the present invention, a control method for an electric brake system comprising a driving unit including a motor that generates a driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor is provided, wherein the control method comprises estimating and updating the point at which the force begins to increase according to the operating distance of the motor due to a braking input by the driver’s brake pedal operation, or the point at which the force becomes zero according to the operating distance of the motor due to the release of the braking input, as the contact point, and moving the brake pad to a preset first operating distance or a preset second operating distance based on the contact point.

[0031] Here, the first operating distance is set to the shortest distance where no drag phenomenon occurs between the brake pad and the disc, and the second operating distance can be set to a distance closer than the first operating distance from the contact point.

[0032] Moving the brake pad to a preset first operating distance or a preset second operating distance based on the contact point may include moving the brake pad to the preset first operating distance based on the contact point when power is applied to the motor or when the braking input is released, and moving the brake pad to the preset second operating distance based on the contact point when an active braking condition of the vehicle is detected.

[0033] In addition, a control method for an electric brake system according to another embodiment of the present invention may further include moving the brake pad, which has been moved to the second operating distance based on the contact point, to the first operating distance based on the contact point when the braking input is released or when there is no braking input for a preset time. Effects of the invention

[0034] The electric brake system and the control method according to the present embodiment can achieve zero drag by preventing the drag phenomenon caused by the gap between the brake pad and the disc.

[0035] The electric brake system and the control method according to the present embodiment can prevent drag phenomena and reduced responsiveness of the brake caused by wear of the brake pads, etc.

[0036] The electric brake system and control method according to the present embodiment can prevent a decrease in brake responsiveness by adjusting the gap between the disc and the brake pad when an active braking condition occurs.

[0037] The electric brake system and control method according to the present embodiment can prevent adverse effects such as temperature rise of the disc, occurrence of drag, and shortening of the brake pad's lifespan caused by the gap between the disc and the brake pad that is adjusted when active braking conditions occur. Brief explanation of the drawing

[0038] FIG. 1 is a schematic diagram of an electric brake system according to one embodiment of the present invention. FIG. 2 is a graph showing the relationship between the operating distance of a motor and the force in an electric brake system according to one embodiment of the present invention. FIG. 3 is a schematic diagram illustrating when power is applied to a motor or when a braking input is released in an electric brake system according to one embodiment of the present invention. FIG. 4 is a schematic diagram illustrating the detection of active braking conditions in an electric brake system according to one embodiment of the present invention. FIG. 5 is a schematic diagram of an electric brake system according to one embodiment of the present invention. FIG. 6 is a flowchart illustrating the sequence of a control method for an electric brake system according to one embodiment of the present invention. Specific details for implementing the invention

[0039] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following embodiments are presented to sufficiently convey the concept of the present invention to those skilled in the art to which the present invention pertains. The present invention is not limited to the embodiments presented herein and may be embodied in other forms. In order to clarify the present invention, the drawings may omit the illustration of parts unrelated to the description and may slightly exaggerate the size of components to aid understanding.

[0040] FIG. 1 is a schematic diagram of an electric brake system according to an embodiment of the present invention. FIG. 2 is a graph showing the relationship between the operating distance of a motor and the force in an electric brake system according to an embodiment of the present invention. FIG. 3 and FIG. 4 are schematic diagrams illustrating the time when power is applied to the motor or when the braking input is released, and when an active braking condition is detected, respectively, in an electric brake system according to an embodiment of the present invention.

[0041] Referring to FIGS. 1 to 4, an electric brake system according to one embodiment of the present invention includes a driving unit (100), a sensor unit (200), and a control unit (300).

[0042] More specifically, the driving unit (100) includes a motor (110) that generates driving force and a brake pad (130) that brakes or releases the vehicle by moving back and forth relative to a disc (120) by means of the motor (110). Additionally, the driving unit (100) may include a spindle and a spindle nut, etc., for converting the rotational motion of the motor (110) into linear motion.

[0043] The sensor unit (200) includes a first sensor (210) that outputs a signal corresponding to the operating distance of the motor (110), a second sensor (220) that outputs a signal corresponding to the force applied to the brake pad (130) from the disc (120), and a third sensor (230) that outputs a signal corresponding to the active brake condition of the vehicle.

[0044] More specifically, the first sensor (210) may be a motor position sensor. Additionally, the second sensor (220) may be a load sensor that estimates the force applied from the disc (120) to the brake pad (130) through the current applied to the motor (110), or is provided on the brake pad (130) or the disc (120) side to measure the force applied from the disc (120) to the brake pad (130). Furthermore, the third sensor (330) may be at least one radar sensor or ultrasonic sensor that detects the condition of the vehicle as well as the front, side, and rear of the vehicle.

[0045] Here, the active braking condition refers to situations similar to those occurring in an Adaptive Cruise Control (Adaptive Cruise Control) or Smart Cruise Control system, such as when the distance to the vehicle ahead decreases rapidly or an obstacle appears, or when the Anti-Lock Brake System (ABS) is activated. This can be detected in various previously disclosed ways.

[0046] The above control unit (300) may include a processor (310) and a memory (320).

[0047] The above processor (310) can control the overall operation of an electric brake system according to one embodiment of the present invention.

[0048] The memory (320) can store a program for processing or controlling the processor (310) and various data for operating an electric brake system according to an embodiment of the present invention.

[0049] For example, the memory (320) may include not only volatile memory such as S-RAM and D-RAM, but also non-volatile memory such as flash memory, ROM (Read Only Memory), and EPROM (Erasable Programmable Read Only Memory).

[0050] More specifically, the control unit (300) estimates and updates the contact point (P) between the disk (120) and the brake pad (130) whenever a braking input or braking input release occurs, and adjusts the distance between the disk (120) and the brake pad (130) based on the contact point (P) according to information measured and detected by the sensor unit (200). At this time, the control unit (300) can estimate the contact point (P) as the point in time when the force begins to increase according to the stroke of the motor (110) caused by the braking input (Apply) or the point in time when the force becomes 0 according to the stroke of the motor (110) caused by the braking input release (Release).

[0051] Here, the braking input and the release of the braking input may be provided by the operation of the driver's brake pedal (not shown). To this end, the sensor unit (200) may further include a sensor that detects the operation of the brake pedal.

[0052] Additionally, the operating distance of the motor (110) can be defined as the travel distance of the brake pad (120) according to the driving of the motor (110), and can be measured by the first sensor (210). Additionally, the force can be measured by the second sensor (220).

[0053] Meanwhile, as illustrated in FIG. 3, when power is applied to the motor (110) or the braking input is released, the control unit (300) moves the brake pad (130) by a preset first operating distance (X) relative to the contact point (P). At this time, the first operating distance (X) can be set as the shortest distance where no drag phenomenon occurs between the brake pad (120) and the disc (130), and the value obtained by subtracting the first operating distance (X) relative to the contact point (P) can be defined as the reference state (Home).

[0054] Accordingly, an electric brake system according to one embodiment of the present invention can achieve zero drag by preventing the drag phenomenon caused by the gap between the brake pad and the disc.

[0055] In addition, the electric brake system according to one embodiment of the present invention can prevent drag phenomena and reduced brake responsiveness by maintaining a constant distance between the brake pad (120) and the disc (130) even if wear of the brake pad (120) occurs, as the control unit (300) updates the contact point (P) in real time when a braking input or brake input release occurs.

[0056] Meanwhile, as illustrated in FIG. 4, the control unit (300) moves the brake pad (120) by a preset second operating distance (Y) relative to the contact point (P) when an active braking condition of the vehicle occurs. At this time, the second operating distance (Y) is set to be closer than the first operating distance (X) from the contact point (P).

[0057] Accordingly, an electric brake system according to one embodiment of the present invention can prevent a decrease in brake responsiveness by adjusting the gap between the disc and the brake pad when an active braking condition occurs.

[0058] Additionally, the control unit (300) may move the brake pad (120) by the first operating distance (X) when the brake input is released while the brake pad (120) is moved by the second operating distance (Y) or when the rotation of the disc (130) is stopped by the brake pad (120). Additionally, the control unit (300) may move the brake pad by the first operating distance (X) when there is no brake input for a preset period of time while the brake pad (120) is moved by the second operating distance (Y).

[0059] Accordingly, an electric brake system according to one embodiment of the present invention can minimize side effects such as temperature rise and drag phenomena of the brake pad (120) or the disc (130) caused by the narrowed gap between the brake pad (120) and the disc (130) under active braking conditions.

[0060] Meanwhile, FIG. 5 is a schematic diagram of an electric brake system according to another embodiment of the present invention.

[0061] Referring to FIGS. 2 and FIGS. 5, an electric brake system according to another embodiment of the present invention may include a driving unit (100) and a sensor unit (200) identical or similar to the above-described embodiment, and the control unit (300) estimates and updates the contact point between the disc and the brake pad whenever a braking input or a braking input release occurs, and when power is applied to the motor or when the braking input is released, moves the brake pad from the disc by a preset first operating distance (X) based on the contact point, and when an active braking condition of the vehicle occurs, moves the brake pad from the disc by a preset second operating distance (Y) based on the contact point.

[0062] At this time, the contact point (P) can be estimated as the point in time when the force begins to increase according to the operating distance of the motor (110) due to the braking input, or the point in time when the force becomes 0 according to the operating distance of the motor (110) due to the release of the braking input, just like in the previously described embodiment.

[0063] Additionally, the first operating distance (X) is set as the shortest distance where no drag occurs between the brake pad (120) and the disc (130), and the second operating distance (Y) is set to be closer than the first operating distance (X) from the contact point (P).

[0064] Additionally, when the braking input is released, the control unit (300) moves the brake pad, which has been moved by the second operating distance (Y) from the disk (130) relative to the contact point (P), by the first operating distance (X) relative to the contact point (P). Additionally, when there is no braking input for a preset time, the drive control unit (330) moves the brake pad (120), which has been moved by the second operating distance (Y) from the disk (130) relative to the contact point (P), by the first operating distance (X) relative to the contact point (P).

[0065] At this time, the operating distance of the motor (110) can be defined as the travel distance of the brake pad (120) according to the driving of the motor (110), and braking input and braking input release can be provided by the driver's operation of the brake pedal.

[0066] Meanwhile, FIG. 6 is a flowchart illustrating the sequence of a control method for an electric brake system according to one embodiment of the present invention.

[0067] Referring to FIGS. 1 to 6, a control method for an electric brake system according to an embodiment of the present invention comprises a driving unit including a motor that generates a driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor, wherein the control method comprises estimating and updating (S100) the point in time when the force begins to increase according to the operating distance of the motor due to a braking input by the driver's operation of the brake pedal, or the point in time when the force becomes 0 according to the operating distance of the motor due to the release of the braking input as the contact point, and moving (S200) the brake pad to a preset first operating distance (X) or a preset second operating distance (Y) based on the contact point.

[0068] In addition, a control method for an electric brake system according to one embodiment of the present invention may further include the step of setting the first operating distance (X) and the second operating distance (Y), and setting a time for moving the brake pad (120), which has been moved by the second operating distance (Y) from the disc (130) based on the contact point (P), by the first operating distance (X) based on the contact point (P) when there is no braking input for a preset time.

[0069] In addition, the estimation and updating (S100) of the contact point (P) is performed in real time by estimating and updating the contact point (P) at the point when the force begins to increase according to the operating distance of the motor (110) or at the point when the force becomes 0 according to the operating distance of the motor (110) due to the release of the braking input, so the contact point (P) is updated whenever the braking input or the braking input is released.

[0070] Additionally, the first operating distance (X) is set to the shortest distance where no drag phenomenon occurs between the brake pad (120) and the disc (130), and the second operating distance (Y) is set to be closer than the first operating distance from the contact point (P).

[0071] More specifically, a control method for an electric brake system according to one embodiment of the present invention moves the brake pad (120) to the first operating distance (X) relative to the contact point (P) when power is applied to the motor (110) or when the braking input is released (S210), and moves the brake pad (120) to the second operating distance (Y) relative to the contact point (P) when an active braking condition of the vehicle is detected (S220).

[0072] In addition, the control method of an electric brake system according to one embodiment of the present invention may move the brake pad (120), which has been moved to the second operating distance (Y) based on the contact point (P), to the first operating distance (X) based on the contact point (P) when conditions occur, such as when the braking input is released, when the rotation of the disc (130) stops, or when there is no braking input for a preset time.

[0073] Accordingly, the control method of an electric brake system according to one embodiment of the present invention can achieve zero drag by preventing the drag phenomenon caused by the gap between the brake pad and the disc.

[0074] In addition, the control method of an electric brake system according to one embodiment of the present invention can achieve zero drag as well as rapid brake responsiveness in situations similar to active braking conditions. Explanation of the symbols

[0075] P. Contact point X. First operating distance Y. Second operating distance 100. Driving unit 110. Motor 120. Disk 130. Brake pad 200. Sensor part 210. First sensor 220. Second sensor 230. Third sensor 300. Control unit 310. Processor 320. Memory

Claims

Claim 1 An electric brake system comprising: a driving unit including a motor that generates a driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor; a sensor unit including a first sensor that outputs a signal corresponding to the operating distance of the motor, a second sensor that outputs a signal corresponding to a force applied from the disc to the brake pad, and a third sensor that outputs a signal corresponding to an active braking condition of the vehicle; and a control unit that estimates and updates a contact point between the disc and the brake pad whenever braking or release of the brake pad occurs based on a signal received from the sensor unit, wherein the control unit adjusts the distance between the disc and the brake pad based on the estimated and updated contact point. Claim 2 An electric brake system according to claim 1, wherein the control unit estimates the point in time when the force begins to increase according to the operating distance of the motor due to the braking input or the point in time when the force becomes 0 according to the operating distance of the motor due to the release of the braking input. Claim 3 An electric brake system according to claim 1, wherein the control unit moves the brake pad by a preset first operating distance based on the contact point when power is applied to the motor or the braking input is released, and the first operating distance is set as the shortest distance where no drag phenomenon occurs between the brake pad and the disc. Claim 4 In paragraph 3, the control unit moves the brake pad by a preset second operating distance based on the contact point when an active braking condition of the vehicle occurs, and the second operating distance is set to be closer than the first operating distance from the contact point, in an electric brake system. Claim 5 In paragraph 4, the control unit is an electric brake system that moves the brake pad by the first operating distance when the braking input is released while the brake pad is moved by the second operating distance. Claim 6 In paragraph 4, the control unit is an electric brake system that moves the brake pad by the first operating distance when there is no braking input for a preset time while the brake pad is moved by the second operating distance. Claim 7 An electric brake system according to claim 1, wherein the operating distance of the motor is defined as the travel distance of the brake pad according to the driving of the motor. Claim 8 In paragraph 2, the braking input and the release of the braking input are provided by the driver's operation of the brake pedal in an electric brake system. Claim 9 An electric brake system comprising: a driving unit including a motor that generates driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor; and a control unit that adjusts the distance between the disc and the brake pad through the driving of the motor; wherein the control unit estimates and updates a contact point between the disc and the brake pad whenever a braking input or release of a braking input occurs, moves the brake pad from the disc by a preset first operating distance based on the contact point when power is applied to the motor or when the braking input is released, and moves the brake pad from the disc by a preset second operating distance based on the contact point when an active braking condition of the vehicle occurs. Claim 10 An electric brake system according to claim 9, wherein the control unit estimates the point in time when the force begins to increase according to the operating distance of the motor due to the braking input or the point in time when the force becomes 0 according to the operating distance of the motor due to the release of the braking input. Claim 11 An electric brake system according to claim 9, wherein the first operating distance is set as the shortest distance between the brake pad and the disc so that no drag phenomenon occurs. Claim 12 An electric brake system according to claim 11, wherein the second operating distance is set closer to the contact point than the first operating distance. Claim 13 In claim 9, the control unit is an electric brake system that moves the brake pad, which has been moved by the second operating distance from the disc based on the contact point, by the first operating distance based on the contact point when the brake input is released. Claim 14 In claim 9, the control unit moves the brake pad, which has been moved by the second operating distance from the disc based on the contact point, by the first operating distance based on the contact point when there is no braking input for a preset time, in an electric brake system. Claim 15 An electric brake system in which, in claim 9, the operating distance of the motor is defined as the travel distance of the brake pad according to the driving of the motor. Claim 16 In paragraph 9, the braking input and braking input release are provided by the driver's operation of the brake pedal in an electric brake system. Claim 17 A control method for an electric brake system comprising a driving unit including a motor that generates a driving force and a brake pad that brakes or releases a vehicle by moving back and forth relative to a disc by the motor, wherein the control method comprises estimating and updating a point in time when the force begins to increase according to the operating distance of the motor due to a braking input or a point in time when the force becomes zero according to the operating distance of the motor due to the release of the braking input as a contact point, and moving the brake pad to a preset first operating distance or a preset second operating distance based on the contact point. Claim 18 A control method for an electric brake system according to claim 17, wherein the first operating distance is set to the shortest distance where no drag phenomenon occurs between the brake pad and the disc, and the second operating distance is set to a distance closer than the first operating distance from the contact point. Claim 19 A control method for an electric brake system according to claim 17, wherein moving the brake pad to a preset first operating distance or a preset second operating distance based on the contact point comprises moving the brake pad to the preset first operating distance based on the contact point when power is applied to the motor or when a braking input is released, and moving the brake pad to the preset second operating distance based on the contact point when an active braking condition of the vehicle is detected. Claim 20 In claim 19, the control method of an electric brake system further comprises moving the brake pad, which has been moved to the second operating distance based on the contact point, to the first operating distance based on the contact point when the brake input is released or when there is no brake input for a preset time.

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