Brake control apparatus and control method of brake apparatus

Abstract

A braking control device installed in a vehicle having multiple wheels comprises: a braking drive unit that applies braking torque to the multiple wheels; and a control unit electrically connected to the braking device, wherein the control unit controls the braking device to apply braking torque to the at least one wheel in response to the spin of at least one of the multiple wheels, reduces the braking torque applied to the at least one wheel in response to the identification of hopping, and increases the braking torque applied to the at least one wheel in steps or linearly in response to the cessation of hopping.

Description

Technology Field

[0001] The disclosed invention relates to a braking control device and a method for controlling a braking device, and more specifically, to a braking control device and a method for controlling a braking device including a Traction Control System (TCS). Background Technology

[0002] Vehicles are essentially equipped with braking devices to perform braking, and braking control devices that control the braking devices in various ways are being proposed for the safety of drivers and passengers.

[0003] Recently, vehicles are being equipped with Traction Control Systems (TCS) to improve traction. The vehicle's Traction Control System controls the driving torque supplied to the wheels to prevent wheel spin.

[0004] In particular, the vehicle's braking control system is equipped with a Brake Traction Control System (BTCS) to improve the vehicle's traction. The Brake Traction Control System can control the braking torque of the wheels to prevent asymmetric spin of the wheels caused by the uneven friction coefficient (Split mu) of the road surface.

[0005] However, in the past, when braking traction control was performed to improve the traction of a vehicle, the vehicle would vibrate significantly due to the periodic change in the rotational speed of the wheel. Such vibration of the vehicle caused by vehicle resonance was called hopping. The problem to be solved

[0006] For the reasons above, one aspect of the disclosed invention aims to provide a braking control device and a method for controlling a braking device that can minimize hopping by braking traction control. means of solving the problem

[0007] According to one aspect of the disclosed invention, a braking control device installed in a vehicle having a plurality of wheels comprises: a braking drive unit that applies braking torque to the plurality of wheels; and a control unit electrically connected to the braking device, wherein the control unit controls the braking device to apply braking torque to the at least one wheel in response to the spin of at least one of the plurality of wheels, reduces the braking torque applied to the at least one wheel in response to the identification of hopping, and can increase the braking torque applied to the at least one wheel in a stepwise or linear manner in response to the cessation of hopping.

[0008] A method for controlling a braking device installed in a vehicle having a plurality of wheels, according to one aspect of the disclosed invention, may include applying a braking torque to at least one wheel in response to spin of at least one wheel among the plurality of wheels; reducing the braking torque applied to the at least one wheel in response to hopping being identified; and increasing the braking torque applied to the at least one wheel in steps or linearly in response to hopping being stopped.

[0009] According to one aspect of the disclosed invention, a braking control device installed in a vehicle having a plurality of wheels comprises: a piston pump including a cylinder and a piston; a driving motor that moves the piston to generate hydraulic pressure; and a control unit electrically connected to the driving motor, wherein the control unit controls the driving motor to generate hydraulic pressure so that the piston pump generates hydraulic pressure to apply braking torque to the at least one wheel in response to the spin of at least one of the plurality of wheels, controls the driving motor to reduce the hydraulic pressure so that the piston pump reduces the braking torque applied to the at least one wheel in response to the identification of hopping, and controls the driving motor to increase the hydraulic pressure so that the piston pump increases the braking torque applied to the at least one wheel in a stepwise or linear manner in response to the cessation of hopping. Effects of the invention

[0010] According to one aspect of the disclosed invention, a braking control device and a method for controlling a braking device can be provided, which can minimize hopping by braking traction control. Brief explanation of the drawing

[0011] FIG. 1 illustrates a driving system and a braking system included in a vehicle according to one embodiment. FIG. 2 illustrates a hydraulic circuit of a braking control device according to one embodiment. FIG. 3 illustrates a control block of a braking control device according to one embodiment. FIG. 4 illustrates wheel speed, hopping, and braking pressure resulting from the operation of a braking control device according to one embodiment. FIG. 5 illustrates the operation of a braking control device according to one embodiment. Specific details for implementing the invention

[0012] Throughout the specification, the same reference numerals refer to the same components. This specification does not describe all elements of the embodiments, and general content in the art to which the disclosed invention pertains or content that overlaps between embodiments is omitted. The terms 'part, module, component, block' used in the specification may be implemented in software or hardware, and depending on the embodiments, a plurality of 'parts, modules, components, blocks' may be implemented as a single component, or a single 'part, module, component, block' may include a plurality of components.

[0013] Throughout the specification, when a part is described as being "connected" to another part, this includes not only cases where they are directly connected but also cases where they are indirectly connected, and indirect connections include connections made via a wireless communication network.

[0014] Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0015] Throughout the specification, when it is stated that a component is located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0016] The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms.

[0017] Singular expressions include plural expressions unless there is an obvious exception in the context.

[0018] In each step, identification codes are used for convenience of explanation and do not describe the order of the steps; the steps may be performed differently from the specified order unless a specific order is clearly indicated in the context.

[0019] The operating principle and embodiments of the disclosed invention will be described below with reference to the attached drawings.

[0020] FIG. 1 illustrates a driving system and a braking system included in a vehicle according to one embodiment.

[0021] The vehicle (1) includes a body that forms its exterior and accommodates a driver and / or luggage, a chassis that includes components of the vehicle (1) other than the body, and a wheel (2) that rotates to allow the vehicle (1) to move.

[0022] Referring to FIG. 1, the vehicle (1) includes a drive system (10) and a braking system (40).

[0023] The drive system (10) generates a driving torque for the vehicle (1) to drive and includes an engine (11), an engine control module (12), and a transmission (21).

[0024] The engine (11) includes cylinders and pistons and can generate driving torque (or driving torque) for the vehicle (1) to drive. The transmission (21) includes a plurality of gears and can transmit the driving torque generated by the engine (11) to the wheels. In particular, the transmission (21) includes a differential gear that allows the left wheel and the right wheel to rotate at different rotational speeds by the driving torque of the engine (11).

[0025] The engine control module (12) may include an electronic control unit (ECU) for controlling the revolutions per minute (rpm) and / or driving torque of the engine (11) in response to the driver's intention to accelerate via the accelerator pedal (11a).

[0026] The braking system (40) generates braking torque to stop the vehicle (1) and includes a braking device (41) and a braking control device (Electronic Brake Control Module, EBCM) (100).

[0027] The braking device (41) may include a brake caliper (42) installed on the wheel (2) of the vehicle (1) as shown in FIG. 1. The brake caliper (42) includes a pair of brake pads provided on both sides of a brake disc (43) connected to the wheel (2). The brake caliper (42) can press the brake disc (43) on both sides of the brake disc (43) by means of fluid pressure or mechanical pressure. The rotation of the brake disc (43) and the wheel (2) can be stopped by friction between the brake pads of the brake caliper (42) and the brake disc (43).

[0028] Additionally, the brake caliper (42) may include a wheel cylinder (44a, 44b, see FIG. 2) that receives a pressurized medium (e.g., brake oil) from a braking control device (100) and causes the brake pad to come into contact with the brake disc by the pressure of the pressurized medium (hereinafter referred to as "hydraulic pressure").

[0029] The braking control device wheel (2) is provided with a wheel speed sensor (180) that detects the rotational speed of the wheel (2).

[0030] The braking control device (100) may include a hydraulic circuit for supplying hydraulic pressure to a wheel cylinder in response to the driver's braking intention through the brake pedal (101), and an electronic control unit for controlling the hydraulic circuit.

[0031] The braking control device (100) can control the hydraulic pressure supplied to the wheel cylinder of the braking device (41) to temporarily release the braking of the wheel in response to slip of the wheel (2) when the vehicle (1) is braking (Anti-lock Braking Systems, ABS).

[0032] The braking control device (100) can control the hydraulic pressure supplied to the wheel cylinder of the braking device (42) to selectively brake the wheel (2) in response to oversteering and / or understeering when steering the vehicle (1) (Electronic stability control, ESC).

[0033] Additionally, the braking control device (100) can control the rotation of the wheel in response to the spin of the wheel (2) when the vehicle (1) is driven. For example, in response to the spin of the wheel (2) detected when the vehicle (1) starts, the braking control device (100) can control the hydraulic pressure supplied to the wheel cylinder of the braking device (42) to temporarily brake the wheel (2). In response to the spin of the wheel (2) detected while the vehicle (1) is driving, the braking control device (100) can control the engine control module (12) to reduce the torque of the engine (11) and can also control the hydraulic pressure supplied to the wheel cylinder of the braking device (42) to temporarily brake the wheel (2).

[0034] The drive system (10) and the braking system (40) can communicate with each other through a vehicle communication network. For example, electrical components can exchange data through Ethernet, MOST (Media Oriented Systems Transport), Flexray, CAN (Controller Area Network), LIN (Local Interconnect Network), etc.

[0035] For example, the engine control module (12) can transmit the rotational speed of the engine (11), the driving torque of the engine (11), the displacement of the accelerator pedal (11a), etc., through a communication network.

[0036] The braking control device (100) receives data including the rotational speed of the engine (11), the driving torque of the engine (11), the displacement of the accelerator pedal (11a), the gear position of the transmission (21), etc., through a communication network, and can control the braking device (41) based on the received data.

[0037] FIG. 2 illustrates a hydraulic circuit of a braking control device according to one embodiment.

[0038] Referring to FIG. 2, the braking control device (100) includes a brake pedal (101) that accepts the driver's intention to brake, a reservoir (103) that stores a pressurizing medium (e.g., brake oil, etc.), a master cylinder (104) that generates hydraulic pressure by the movement of the brake pedal (101), a piston pump (160) that generates hydraulic pressure in response to the detection of the movement of the brake pedal (101), a drive motor (150) that drives the piston pump (160), and a hydraulic circuit (110) that connects the master cylinder (104) and / or the piston pump (160) to wheel cylinders (44a, 44b).

[0039] The piston pump (160) includes a cylinder (161) and a piston (162), and the internal space of the cylinder (161) can be divided into a first pressure chamber (161a) and a second pressure chamber (161b) by the piston (162).

[0040] The piston pump (160) can generate hydraulic pressure by the movement of the piston (162) in response to the movement of the brake pedal (101). A brake pedal sensor (130) that detects the movement of the brake pedal (101) may be provided, and the piston (162) of the piston pump (160) may move based on the output of the brake pedal sensor (130).

[0041] The drive motor (150) can generate rotational force to move the piston (162). The rotational force of the drive motor (150) is converted into reciprocating force through a power transmission unit (e.g., a plurality of gears), and the piston (162) can reciprocate by the reciprocating force converted by the power transmission unit.

[0042] The hydraulic pressure circuit (110) hydraulically connects the piston pump (160) to the wheel cylinders (44a, 44b) and can transmit or block the hydraulic pressure generated from the piston pump (160) to the wheel cylinders (44a, 44b).

[0043] The hydraulic circuit (110) includes a main flow path (111) connecting the piston pump (160) to the wheel cylinders (44a, 44b), and also includes a hydraulic control unit (117), inlet valves (113a, 113b), and outlet valves (114a, 114b) on the main flow path (111).

[0044] The hydraulic pressure control unit (117) can be hydraulically connected to the first pressure chamber (161a) and the second pressure chamber (161b) of the piston pump (160) and may include a plurality of valves. The hydraulic pressure control unit (117) can guide the hydraulic pressure generated by the piston pump (160) to the wheel cylinders (44a, 44b). For example, the hydraulic pressure control unit (117) can guide the hydraulic pressure generated in the first pressure chamber (161a) to the wheel cylinders (44a, 44b) while the piston (162) is advancing, and the hydraulic pressure generated in the second pressure chamber (161b) to the wheel cylinders (44a, 44b) while the piston (162) is retracting.

[0045] In the hydraulic pressure control unit (117), the main flow path (111) branches into a first main flow path (111a) and a second main unit (111b), the first main flow path (111a) extends to a first wheel cylinder (44a) associated with a first wheel (2a), and the second main flow path (111b) extends to a second wheel shield (44b) associated with a second wheel (2b). Here, the first wheel (2a) and the second wheel (2b) may be wheels provided on the left and right sides of the vehicle (1), respectively. For example, the first wheel (2a) may be a left front wheel or a left rear wheel, and the second wheel (2b) may be a right front wheel or a right rear wheel.

[0046] Inlet valves (113a, 113b) and outlet valves (114a, 114b) may be provided in each of the first main Euro (111a) and the second main unit (111b).

[0047] Inlet valves (113a, 113b) are positioned on a main passage (111a, 111b) connecting the piston pump (160) to the wheel cylinder (44a, 44b). A first inlet valve (113a) may be provided in the first main passage (111a), and a second inlet valve (113b) may be provided in the second main unit (111b). The inlet valves (113a, 113b) may allow or block hydraulic pressure transmitted from the piston pump (160) to the wheel cylinder (44a, 44b). The inlet valves (113a, 113b) may be normally open solenoid valves.

[0048] Outlet valves (114a, 114b) are positioned on the path connecting the wheel cylinders (44a, 44b) to the reservoir (103). A first outlet valve (114a) is provided on the path connecting the first wheel cylinder (44a) to the reservoir (103), and a second outlet valve (114b) is provided on the path connecting the second wheel cylinder (44b) to the reservoir (103). The outlet valves (114a, 114b) can allow or block the hydraulic pressure of the wheel cylinders (44a, 44b) from being discharged to the reservoir (103). The outlet valves (114a, 114b) may be normally closed solenoid valves.

[0049] The hydraulic circuit (110) further includes an auxiliary passage (112) connecting the master cylinder (104) to the wheel cylinder (44a) and a cut valve (118) provided on the auxiliary passage (112).

[0050] The cut valve (118) can prevent the hydraulic pressure of the master cylinder (104) from being supplied to the wheel cylinder (44a). In other words, the cut valve (118) can block the hydraulic pressure of the master cylinder (104) and allow the hydraulic pressure of the piston pump (160) to be supplied to the wheel cylinder (44a).

[0051] If the piston pump (160) is in a broken or uncontrollable state, the cut valve (118) may be opened, and the opening of the cut valve (118) may allow the hydraulic pressure of the master cylinder (104) to be supplied to the wheel cylinder. The cut valve (118) may be a normally open solenoid valve that is normally open to allow connection between the piston pump (160) and the wheel cylinders (44a, 44b) when power is lost.

[0052] The hydraulic pressure circuit (110) further includes check valves installed at appropriate flow path locations to prevent reverse flow of brake fluid. Valves included in the braking control device (100), such as inlet valves (113a, 113b), outlet valves (114a, 114b), hydraulic pressure control unit (117), cut valve (118), and check valve, can form a valve block as a whole.

[0053] The braking control device (100) may further include a pressure sensor (140) for measuring the hydraulic pressure of the hydraulic pressure circuit (110).

[0054] When the driver presses the brake pedal (101), the piston pump (160) can supply hydraulic pressure to the wheel cylinders (44a, 44b) through the hydraulic pressure control unit (117) and inlet valves (113a, 113b).

[0055] Additionally, the braking control device (100) can generate and control hydraulic pressure to realize the ABS and / or ESC and / or BTCS described above.

[0056] FIG. 3 illustrates a control block of a braking control device according to one embodiment. FIG. 4 illustrates wheel speed, hopping, and braking pressure according to the operation of a braking control device according to one embodiment.

[0057] As illustrated in FIG. 3, the braking control device vehicle (1) is provided with a brake pedal sensor (130) that detects the movement of the brake pedal (101), a wheel speed sensor (180) that detects the rotational speed of the wheel (2), and a motion sensor (190) that detects the movement of the vehicle (1). The braking control device (100) includes a pressure sensor (140) that detects pressure within a hydraulic pressure circuit (110), a piston pump (160) that generates hydraulic pressure to supply to wheel cylinders (44a, 44b), a drive motor (150) that drives the piston pump (160), a valve block (170) that opens or closes a path guiding the hydraulic pressure generated by the piston pump (160) to the wheel cylinders (44a, 44b), and a control unit (120) that controls the operation of the braking control device (100).

[0058] The brake pedal sensor (130) can detect the distance traveled and / or speed traveled by the brake pedal (101) due to the driver's intention to brake, and can provide an electrical output signal (pedal signal) dependent on the detected distance traveled and / or speed traveled to the control unit (120). The control unit (120) can determine the driver's intention to brake based on the pedal signal of the brake pedal sensor (130).

[0059] A pressure sensor (140) is provided on a hydraulic pressure circuit (110) that provides hydraulic pressure to wheel cylinders (44a, 44b) and can detect the hydraulic pressure of a pressurized medium on the hydraulic pressure circuit (110). The pressure sensor (140) can provide an electrical output signal (pressure signal) dependent on the detected hydraulic pressure to a control unit (120). The control unit (120) can determine the hydraulic pressure generated by the master cylinder (104) and / or piston pump (160) based on the pressure signal of the pressure sensor (140).

[0060] The location and number of pressure sensors (140) are not limited. For example, the pressure sensors (140) may be provided in a location capable of detecting the hydraulic pressure generated by the master cylinder (104) and / or the piston pump (160). Additionally, a sufficient number of pressure sensors (140) capable of detecting the hydraulic pressure generated by the master cylinder (104) and / or the piston pump (160) may be provided.

[0061] The wheel speed sensor (180) can detect the rotational speed of the wheel (2) provided on the vehicle (1). The wheel speed sensor (180) is installed on each of the multiple wheels (e.g., four wheels) and can detect the rotational speed of each of the multiple wheels. For example, the wheel (2) of the vehicle (1) may be provided with a toothed ring having a plurality of metal poles formed on its outer surface, and the wheel speed sensor (180) may include a rod-shaped permanent magnet and a coil that winds the permanent magnet. The wheel speed sensor (180) is provided around the toothed ring so that the pole (N pole or S pole) of the permanent magnet faces the toothed ring of the wheel (2). The rotation of the toothed ring caused by the rotation of the wheel (2) causes a change in the magnetic field around the permanent magnet, and the coil of the wheel speed sensor (180) can transmit an electrical signal (AC signal) corresponding to the change in the magnetic field around the permanent magnet to the control unit (120). The control unit (120) can identify the rotational speed of the wheel (2) based on the electrical signal of the wheel speed sensor (180).

[0062] The motion sensor (190) can detect the movement of the vehicle (1), including linear acceleration and rotational acceleration of the vehicle (1), and provide an electrical signal corresponding to the movement of the vehicle (1) to the control unit (120). For example, the motion sensor (190) can detect the vertical acceleration, longitudinal acceleration, and lateral acceleration of the vehicle (1) based on changes in gravitational acceleration acting on the vehicle (1). Additionally, the motion sensor (190) can detect the yaw rate, roll rate, and pitch rate of the vehicle (1) using rotational inertia or Coriolis force.

[0063] A piston pump (160) can generate hydraulic pressure by receiving rotational force from a drive motor (150). The piston pump (160) includes, for example, a cylinder (161) and a piston (162), and can generate hydraulic pressure by the movement of the piston (162) by the rotation of the drive motor (150).

[0064] The drive motor (150) can generate rotational force in response to a drive signal from the control unit (120). The rotational force generated by the drive motor (150) can be supplied to the piston pump (160). The drive motor (150) may include, for example, a brushless direct current motor (BLDC motor), a permanent magnet synchronous motor (PMSM), a DC motor, an induction motor, etc.

[0065] The valve block (170) may include a plurality of valves of the braking control device (100). For example, the valve block (170) may include inlet valves (113a, 113b), outlet valves (114a, 114b), a hydraulic pressure control unit (117), and a cut valve (118) as shown in FIG. 2.

[0066] The valve block (170) can open or close the fluid path included in the hydraulic circuit (110) in response to a control signal (open signal or close signal) from the control unit (120). For example, the valve block (170) can provide a fluid path that guides hydraulic pressure from the master cylinder (104) to the wheel cylinders (44a, 44b) as shown in FIG. 2, or provide a fluid path that guides hydraulic pressure from the piston pump (160) to the wheel cylinders (44a, 44b).

[0067] The control unit (120) can control the drive motor (150) and the valve block (170) based on the output signal (pedal signal) of the brake pedal sensor (130), the output signal (pressure signal) of the pressure sensor (140), the output signal (wheel speed signal) of the wheel speed sensor (180), and the output signal (motion signal) of the motion sensor (190). Additionally, the control unit (120) can obtain data related to the driving of the vehicle (1) from the engine control module (12) via a vehicle communication network, and can control the drive motor (150) and the valve block (170) based on the data related to the driving of the vehicle (1).

[0068] The control unit (120) may include a plurality of semiconductor devices and may be referred to in various ways, such as an ECU (Electronic Control Unit). The control unit (120) includes a CAN transceiver (123), a memory (122), and a processor (121). The CAN transceiver (123), the memory (122), and the processor (121) may each be implemented as separate semiconductor devices or as a single semiconductor device. The control unit (120) may include a plurality of processors and / or a plurality of memories.

[0069] A CAN transceiver (123) can receive data related to the driving of a vehicle (1) from an engine control module (12) via a vehicle communication network. For example, the CAN transceiver (123) can receive data including the displacement of the accelerator pedal (11a) and the driving torque of the engine (11) from the engine control module (12), and can transmit the received data to a processor (121).

[0070] The memory (122) can store / restore programs and data for braking the vehicle (1) depending on the driver's braking intent. For example, the memory (122) can store / restore programs and data for controlling the drive motor (150) and the valve block (170) to provide hydraulic pressure to the wheel cylinders (44a, 44b) depending on the driver's braking intent. Additionally, the memory (122) can store / restore programs and data for controlling the drive motor (150) and the valve block (170) to provide hydraulic pressure to the wheel cylinders (44a, 44b) depending on the displacement of the accelerator pedal (11a) and / or the driving torque of the engine (11).

[0071] The memory (122) provides programs and data to the processor (121) and can store temporary data generated during the operation of the processor (121).

[0072] The memory (122) may include volatile memory such as S-RAM (Static Random Access Memory, S-RAM) and D-RAM (Dynamic Random Access Memory, D-RAM), and non-volatile memory such as ROM (Read Only Memory: ROM), EPROM (Erasable Programmable Read Only Memory: EPROM), and flash memory. The memory (122) may include a single semiconductor device or a plurality of semiconductor devices.

[0073] The processor (121) can provide control signals to the drive motor (150) and the valve block (170) according to the program and data provided from the memory (122). For example, the processor (121) can provide a drive signal to the drive motor (150) to generate hydraulic pressure, and can provide an opening / closing signal to the valve block (170) to guide the hydraulic pressure from the piston pump (160) to the wheel cylinders (44a, 44b).

[0074] The processor (121) may include an arithmetic circuit, a memory circuit, and a control circuit. The processor (121) may include a single semiconductor device or a plurality of semiconductors. Additionally, the processor (121) may include a single core or a plurality of cores within a single semiconductor device. Such a processor (121) may be referred to in various ways, such as an MPU (Micro Processing Unit).

[0075] In this way, the control unit (120) can control the drive motor (150) and / or valve block (170) to brake the vehicle (1) by relying on the output signal output from the brake pedal sensor (130).

[0076] Wheel spin may occur when the vehicle (1) starts or travels on a road with a low friction coefficient. For example, spin may occur in the drive wheel (a wheel driven by a drive system), and due to the wheel spin, the vehicle (1) may not be able to move forward and may slide.

[0077] Additionally, wheel spin may occur when the vehicle (1) starts or travels on a road with a non-uniform (split-mu) friction coefficient. For example, spin may occur in either the left drive wheel or the right drive wheel. When wheel spin occurs, the driving torque of the engine (11) may be biased and supplied to the wheel where the spin occurred due to the differential gear. As a result, the vehicle (1) may be unable to move forward and may slide on the road.

[0078] The braking control device (100) can control the spin of the wheel to improve traction (the force that the vehicle intends to move forward) on a road surface with a low friction coefficient or on a road surface with an uneven friction coefficient. The control unit (120) can detect the spin of the wheel (2) based on the difference in rotational speed between the wheels (e.g., the difference in rotational speed between the driving wheel and the driven wheel, or the difference in rotational speed between the left wheel and the right wheel). When the spin of the wheel is detected to be greater than the target spin, the control unit (120) can control the driving torque and braking torque provided to the wheel so that the spin of the wheel becomes smaller than the target spin. For example, the control unit (120) can provide a message to the engine control module (12) to reduce the driving torque of the engine (11), and can provide braking torque to the wheel to reduce the rotational speed of the wheel where the spin was detected. In particular, when spin is detected in either the left wheel or the right wheel, the control unit (120) can provide braking torque to the wheel where spin is detected in order to balance the driving torque of the left wheel and the right wheel.

[0079] During braking traction control, the rotational speed of the wheels (2a, 2b) may change periodically. For example, if the wheel spin changes near the target spin, the braking control device (100) may periodically apply braking torque to the wheels (2a, 2b) based on a comparison of the wheel spin and the target spin. As a result, the rotational speed of the wheels (2a, 2b) may change at a constant period. Additionally, wheel spin may occur periodically due to the braking torque applied to the wheels (2a, 2b) by the braking control device (100), and as a result, the rotational speed of the wheels (2a, 2b) may change periodically.

[0080] At this time, if the period of change in the rotational speed of the wheels (2a, 2b) roughly matches the natural vibration period of the vehicle (1), the vehicle (1) can vibrate significantly due to resonance. Such vibration of the vehicle (1) is called hopping.

[0081] Such hopping occurs due to the interaction between the vehicle's (1) drive system (10), braking system (40), suspension system, and road surface, and continues for a considerable amount of time, causing discomfort and anxiety to the driver. In particular, when the vehicle (1) vibrates at a frequency of approximately 6 to 8 Hz (hertz), the driver can detect the hopping of the vehicle (1) and feel anxiety.

[0082] The control unit (120) can identify hopping of the vehicle (1) based on the output of the wheel speed sensor (180). If the frequency of the change in speed of the wheels (2a, 2b) detected by the wheel speed sensor (180) is within a predetermined range of frequencies and the magnitude of the change in speed of the wheels (2a, 2b) is greater than or equal to a predetermined amplitude, the control unit (120) can identify hopping. For example, if the speed of the wheels (2a, 2b) changes at a frequency between approximately 6 to 8 Hz (hertz) and changes at an amplitude between approximately 5 kph (km per hour) and 10 kph, the control unit (120) can identify hopping of the vehicle (1).

[0083] For example, the control unit (120) can detect the difference between the rotational speed (W2) of the wheels (2a, 2b) and the driving speed (VS) of the vehicle (1) at time t0 as shown in FIG. 4 (a), and can identify the spin of the wheels (2a, 2b) based on this. In response to detecting the spin of the wheels (2a, 2b), the control unit (120) can apply braking torque to the wheels (2a, 2b). Specifically, the control unit (120) can supply braking pressure to the wheel cylinders (44a, 44b) at time t0 as shown in FIG. 4 (c). Due to the braking torque, the spin of the wheels (2a, 2b) can be reduced.

[0084] Subsequently, while the spin of the wheels (2a, 2b) is reduced, the rotational speed of the wheels (2a, 2b) may change periodically as shown in FIG. 4 (a). The control unit (120) can detect the rotational speed of the wheels (2a, 2b) changing periodically through the wheel speed sensor (180), and can identify hopping at time t1 as shown in FIG. 4 (b) based on the periodic change in the rotational speed of the wheels (2a, 2b). Specifically, if the frequency of change in the rotational speed of the wheels (2a, 2b) is approximately between 6 Hz and 8 Hz and the amplitude of change in the rotational speed is approximately between 5 kph and 10 kph, the control unit (120) can identify hopping.

[0085] When hopping is identified, the control unit (120) can stop the rotational speed of the wheels (2a, 2b) from changing periodically. For example, the control unit (120) can decrease or increase the braking torque applied to the wheels (2a, 2b) for braking traction control. However, since the traction force of the vehicle (1) may decrease as the braking torque applied to the wheels (2a, 2b) increases, the control unit (120) can decrease the braking torque applied to the wheels (2a, 2b).

[0086] In response to identifying hopping, the control unit (120) can reduce the braking torque at time t1 as shown in (c) of FIG. 4.

[0087] The control unit (120) can reduce the braking torque at a predetermined rate in response to identifying hopping. For example, the control unit (120) can apply the reduced braking torque to the wheels (2a, 2b) using [Equation 1].

[0088] [Mathematical Formula 1]

[0089]

[0090] Here, BT_hopping represents the braking torque in response to the identification of hopping, BT_normal represents the braking torque due to wheel spin, and α represents the braking torque reduction factor due to the identification of hopping. α can be a real number less than "1" and greater than "0".

[0091] In addition, the control unit (120) can reduce the braking torque by a predetermined amount in response to identifying the hopping.

[0092] By reducing the braking torque applied to the wheels (2a, 2b), the frequency at which the rotational speed of the wheels (2a, 2b) vibrates can be changed. As a result, the frequency at which the rotational speed of the wheels (2a, 2b) changes deviates from the natural vibration frequency of the vehicle (1), and the vibration of the vehicle (1) can be reduced.

[0093] For example, as shown in FIG. 4 (a), the magnitude of the change in the rotational speed of the wheels (2a, 2b) after time t2 may decrease, and the control unit (120) may identify that hopping has stopped at time t2 as shown in FIG. 4 (b).

[0094] In response to identifying that hopping has stopped, the control unit (120) can restore the braking torque reduced due to the detection of hopping in steps or linearly. For example, the control unit (120) can increase the braking torque in steps or linearly between time t2 and time t3 from the value reduced due to the detection of hopping to a value that responds to wheel spin, as shown in (c) of FIG. 4.

[0095] The control unit (120) can increase the braking torque stepwise or linearly using [Equation 2].

[0096] [Mathematical Formula 2]

[0097]

[0098] Here, BT_after_hopping represents the braking torque after hopping has stopped, BT_normal represents the braking torque due to wheel spin, and α may represent the braking torque reduction factor due to identification of hopping. α may be a real number less than "1" and greater than "0". t_after_hopping represents the time elapsed since hopping has stopped, and t_reference may represent the reference transition time to recover the braking torque after hopping has stopped.

[0099] According to [Equation 2], when the time t_after_hopping elapsed after hopping is stopped is "0", the braking torque BT_after_hopping is BT_normal*α, and when the time t_after_hopping elapsed after hopping is stopped reaches the reference transition time t_reference, the braking torque BT_after_hopping becomes BT_normal. In other words, the braking torque can increase linearly during the reference transition time t_reference.

[0100] In this way, by recovering the reduced braking torque due to the identification of hopping in stages or linearly to the braking torque that responds to wheel spin, the stability of the vehicle (1) is ensured and the driver's sense of strangeness regarding the braking of the vehicle (1) can be minimized.

[0101] FIG. 5 illustrates the operation of a braking control device according to one embodiment.

[0102] Together with FIG. 5, the operation (1000) of the braking control device (100) according to operating conditions is described.

[0103] The braking control device (100) enables braking traction control (1010).

[0104] The braking control device (100) can detect wheel spin based on the output of the wheel speed sensor (180). If the wheel spin is greater than the reference spin, the braking control device (100) can activate braking traction control.

[0105] The braking control device (100) applies braking torque to the wheels (2a, 2b) according to wheel spin (1020).

[0106] While braking traction control is activated, the braking control device (100) can apply braking torque to the wheels (2a, 2b) where wheel spin is detected based on the difference between the target spin and the wheel spin. For example, the braking control device (100) can determine the braking torque corresponding to the wheel spin exceeding the target spin, determine the hydraulic pressure of the wheel cylinders (44a, 44b) corresponding to the determined braking torque, and determine the displacement of the piston (162) of the piston pump (160) for generating the determined hydraulic pressure.

[0107] The braking control device (100) can control the drive motor (150) to move the piston (162) of the piston pump (160), thereby applying braking torque to the wheels (2a, 2b).

[0108] The braking control device (100) determines whether hopping is detected (1030).

[0109] During braking traction control, the rotational speed of the wheels (2a, 2b) may change periodically. At this time, if the period of change in the rotational speed of the wheels (2a, 2b) roughly matches the natural vibration period of the vehicle (1), the vehicle (1) may vibrate significantly due to resonance. Such vibration of the vehicle (1) is called hopping.

[0110] The control unit (120) can identify hopping of the vehicle (1) based on the output of the wheel speed sensor (180). If the frequency of the change in speed of the wheels (2a, 2b) detected by the wheel speed sensor (180) is within a predetermined range of frequencies and the magnitude of the change in speed of the wheels (2a, 2b) is greater than or equal to a predetermined amplitude, the control unit (120) can identify hopping.

[0111] When hopping is detected (e.g., 1030), the braking control device (100) applies reduced braking torque to the wheels (2a, 2b) (1040).

[0112] When hopping is identified, the braking control device (100) can reduce the braking torque applied to the wheels (2a, 2b) to stop the rotational speed of the wheels (2a, 2b) from changing periodically. For example, the braking control device (100) can reduce the braking torque by a predetermined ratio α.

[0113] By reducing the braking torque applied to the wheels (2a, 2b), the frequency at which the rotational speed of the wheels (2a, 2b) vibrates changes, and as a result, the vibration of the vehicle (1) can be reduced.

[0114] If hopping is not detected (No in 1030), the braking control device (100) determines whether the time elapsed since the hopping stopped is less than the reference time (1050).

[0115] The braking control device (100) includes a counter and can count the time elapsed since hopping stopped based on the output of the counter.

[0116] The braking control device (100) can compare the time counted after hopping stopped (t_after_hopping) with a reference time (t_reference) and determine whether the time counted after hopping stopped (t_after_hopping) is smaller than the reference time (t_reference).

[0117] If the time elapsed since the hopping stopped is less than the reference time (e.g., 1050), the braking control device (100) increases the braking torque reduced due to the detection of the hopping according to the time elapsed since the hopping stopped (1060).

[0118] In response to identifying that hopping has stopped, the braking control device (100) may increase the braking torque reduced due to the detection of hopping in steps or linearly. For example, the braking control device (100) may increase the braking torque linearly in proportion to the time elapsed since the hopping stopped.

[0119] The braking control device (100) can increase the braking torque so that the braking torque reaches the braking torque caused by wheel spin when the time elapsed since the hopping stopped reaches the reference time.

[0120] If the time elapsed since the hopping stopped is not less than the reference time (No in 1050), the braking control device (100) applies braking torque by wheel spin to the wheels (2a, 2b) (1070).

[0121] When the time elapsed since the hopping stopped reaches the reference time, the braking control device (100) can apply braking torque to the wheels (2a, 2b) corresponding to the wheel spin detected by the output of the wheel speed sensor (180).

[0122] In this way, the braking control device (100) can secure the stability of the vehicle (1) and minimize the strange sensation felt by the driver regarding the braking of the vehicle (1) by recovering the braking torque reduced by the identification of hopping in stages or linearly to the braking torque that responds to wheel spin.

[0123] Meanwhile, the disclosed embodiments may be implemented in the form of a recording medium that stores instructions executable by a computer. The instructions may be stored in the form of program code and, when executed by a processor, may generate a program module to perform the operation of the disclosed embodiments. The recording medium may be implemented as a computer-readable recording medium.

[0124] As described above, the disclosed embodiments have been explained with reference to the attached drawings. Those skilled in the art will understand that the present invention may be practiced in forms different from the disclosed embodiments without changing the technical spirit or essential features of the invention. The disclosed embodiments are illustrative and should not be interpreted restrictively. Explanation of the symbols

[0125] 1: Vehicle 2: Wheel 10: Drive System 10a: Accelerator Pedal 11: Engine 12: Engine control module 21: Transmission 40: Braking System 41: Braking system 42: Brake caliper 43: Brake disc 44a, 44b: Wheel cylinder 100: Braking control unit 101: Brake pedal 103: Reservoir 104: Master Cylinder 110: Hydraulic circuit 111: Main Euro 3 112: Auxiliary Euro 113a, 113b: Inlet Valve 114a, 114b: Outlet valves 117: Hydraulic pressure control unit 118: Cut valve 120: Control unit 121: Processor 122: Memory 123: CAN transceiver 130: Brake pedal sensor 140: Pressure sensor 150: Drive motor 160: Piston pump 161: Cylinder 162: Piston 170: Valve Block 180: Wheel speed sensor 190: Motion sensor

Claims

Claim 1 A braking control device installed in a vehicle having a plurality of wheels, comprising: a braking unit that applies braking torque to the plurality of wheels; and a control unit electrically connected to the braking unit, wherein the control unit controls the braking unit to apply braking torque to the at least one wheel in response to the spin of at least one of the plurality of wheels, reduces the braking torque applied to the at least one wheel in response to the identification of hopping, and in response to the cessation of the hopping and the frequency of the change in the rotational speed of the at least one wheel deviating from the natural vibration frequency of the vehicle, increases the braking torque applied to the at least one wheel stepwise or linearly in proportion to the time elapsed after the cessation of the hopping by the braking torque reduced due to the detection of the hopping. Claim 2 In claim 1, the control unit is a braking control device that identifies the hopping based on the frequency and vibration of the change in rotational speed of at least one wheel. Claim 3 In paragraph 2, the control unit identifies the hopping based on the frequency of the change in the rotational speed of the at least one wheel being between 6 Hz (Hertz) and 8 Hz, and the amplitude of the change in the rotational speed of the at least one wheel being between 5 kph (km per hour) and 10 kph. Claim 4 In claim 1, the control unit is a braking control device that reduces the braking torque applied to the at least one wheel by a predetermined ratio in response to the identification of the hopping. Claim 5 delete Claim 6 A method for controlling a braking device installed in a vehicle having multiple wheels, comprising: applying a braking torque to at least one wheel in response to the spin of at least one wheel among the multiple wheels; reducing the braking torque applied to the at least one wheel in response to the identification of hopping; and increasing the braking torque applied to the at least one wheel in steps or linearly in response to the cessation of the hopping and the deviation of the frequency of the change in the rotational speed of the at least one wheel from the natural vibration frequency of the vehicle, wherein increasing the braking torque comprises increasing the braking torque reduced due to the detection of the hopping in proportion to the time elapsed after the cessation of the hopping in response to the cessation of the hopping. Claim 7 A control method for a braking device according to claim 6, wherein the control method further comprises identifying the hopping based on the frequency and vibration of the change in rotational speed of at least one wheel. Claim 8 A control method for a braking device according to claim 7, further comprising identifying the hopping based on the frequency of the change in rotational speed of at least one wheel being between 6 Hz (Hertz) and 8 Hz and the amplitude of the change in rotational speed of at least one wheel being between 5 kph (km per hour) and 10 kph. Claim 9 A method for controlling a braking device according to claim 6, wherein reducing the braking torque comprises reducing the braking torque applied to at least one wheel by a predetermined ratio in response to the identification of the hopping. Claim 10 delete Claim 11 A braking control device installed in a vehicle having multiple wheels, comprising: a piston pump including a cylinder and a piston; a driving motor for moving the piston to generate hydraulic pressure; and a control unit electrically connected to the driving motor, wherein the control unit controls the driving motor to generate hydraulic pressure to apply braking torque to the at least one wheel in response to the spin of at least one of the multiple wheels; controls the driving motor to reduce hydraulic pressure to the piston pump in response to the detection of hopping in order to reduce the braking torque applied to the at least one wheel; and controls the driving motor to increase hydraulic pressure to the piston pump in response to the cessation of hopping in order to increase the braking torque applied to the at least one wheel stepwise or linearly in proportion to the time elapsed after the cessation of hopping by the braking torque reduced due to the detection of hopping.

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