KR20230122358A - Method for controlling auto vehicle hold system - Google Patents

Abstract

The automatic vehicle hold control method determines whether the driver's braking pressure and vehicle speed satisfy the AVH control entry condition when the AVH (Auto Vehicle Hold) switch is turned on, and if the AVH control entry condition is satisfied, the vehicle stops based on the longitudinal acceleration of the vehicle. Estimating the gradient of the road surface in progress, determining the target braking pressure to keep the vehicle stationary according to the gradient of the road surface, and determining the pressure rise gradient of the AVH control pressure according to the vehicle speed when the driver's braking pressure is lower than the target braking pressure , generating an AVH control pressure according to a pressure rise gradient, and supplying the AVH control pressure to each wheel to increase the wheel pressure to a target braking pressure.

Description

Automatic vehicle hold control method {METHOD FOR CONTROLLING AUTO VEHICLE HOLD SYSTEM}

The present invention relates to an automatic vehicle hold control method for performing an automatic vehicle stop maintenance function.

In general, an AUTO VEHICLE HOLD (AVH) function is a driver's convenience function that maintains braking pressure when the vehicle is stopped.

One of the important performance factors of the AVH function is to minimize a jerk when AVH control is entered or AVH control is released so that the driver does not feel uncomfortable.

It is a brake-by-wire system that replaces the mechanical connection between the master cylinder, booster, ABS (Anti-lock Brake System)/ESC (Electric Stability Control) devices with electrical and electronic connections to make it electrical, and master An integrated electronic brake system that can reduce engine load, reduce weight, and secure design flexibility by integrating a cylinder and an electric actuator into one block is being developed.

The AVH function of a vehicle equipped with such an integrated electronic brake system can increase the pressure to a preset control pressure even when the vehicle brakes below the minimum braking pressure capable of maintaining the vehicle stop for each incline for the driver's convenience. In this case, if the pressure is increased at a constant slope, a jerk may occur when the vehicle comes to a complete stop because the pressure is increased when the AVH control entry speed condition of 0.25 to 0.75 kph or less is satisfied.

Publication No. 10-2015-0064912 (published on June 12, 2015)

One aspect provides an automatic vehicle hold control method capable of minimizing jerk by applying an appropriate pressure control pattern for each situation when braking pressure is generated by satisfying AVH control entry conditions or when braking pressure is released by satisfying AVH control release conditions. do.

According to one aspect, when an AVH (Auto Vehicle Hold) switch is turned on, it is determined whether the driver's braking pressure and vehicle speed satisfy the AVH control entry condition, and if the AVH control entry condition is satisfied, the vehicle stops from the longitudinal acceleration of the vehicle. Estimating the gradient of the road surface in progress, determining a target braking pressure for maintaining the vehicle stop according to the gradient of the road surface, and when the driver's braking pressure is lower than the target braking pressure, the pressure of the AVH control pressure according to the vehicle speed An automatic vehicle hold control method comprising determining a rising slope, generating the AVH control pressure according to the pressure rising slope, and supplying the AVH control pressure to each wheel to increase the wheel pressure to the target braking pressure. It can be.

Determining the pressure increase slope of the AVH control pressure may include determining a different pressure increase slope of the AVH control pressure before and after the vehicle is completely stopped.

Determining the pressure increase slope of the AVH control pressure may include determining a pressure increase slope of the AVH control pressure before the vehicle is completely stopped than a pressure increase slope of the AVH control pressure when the vehicle is completely stopped. can

Determining the pressure increase slope of the AVH control pressure is to determine the pressure increase slope of the AVH control pressure to increase relatively gently before the vehicle is completely stopped, and to be relatively rapid when the vehicle is completely stopped. It may include determining to increase

Determining the pressure increase slope of the AVH control pressure determines the pressure increase slope of the AVH control pressure to increase relatively slowly before the vehicle is completely stopped, and to increase relatively quickly when the vehicle is completely stopped. It includes deciding to be

According to another aspect, if the EPB (Electronic Parking Brake) engagement occurs during AVH (Auto Vehicle Hold) control, it is determined that the AVH control release condition is satisfied, and if the AVH control release condition is satisfied, the longitudinal acceleration of the vehicle is determined. The pitching motion caused by twisting in the pitch direction of the vehicle is determined, and when the AVH control is released according to the pitching motion, a pressure drop slope of the AVH control pressure is determined, and the AVH control pressure is reduced according to the pressure drop slope. An automatic vehicle hold control method including releasing AVH control may be provided.

Determining the pressure drop slope of the AVH control pressure may include determining the pressure drop slope of the AVH control pressure differently depending on whether the vehicle has a pitch motion.

Determining the pressure drop slope of the AVH control pressure may include determining a pressure drop slope of the AVH control pressure when the vehicle has a pitch motion lower than a pressure drop slope of the AVH control pressure when there is no pitch motion. can

Determining the pressure drop slope of the AVH control pressure determines the pressure drop slope of the AVH control pressure to decrease relatively slowly when the vehicle has a pitch motion and to decrease relatively quickly when the vehicle does not have a pitch motion. This may include deciding to

According to another aspect, when the AVH (Auto Vehicle Hold) switch is turned on, it is determined whether the driver's braking pressure and the vehicle speed satisfy the AVH control entry condition, and if the AVH control entry condition is satisfied, the vehicle moves from the longitudinal acceleration of the vehicle. Estimating the gradient of the road surface in which the vehicle is stopped, determining a target braking pressure for maintaining the vehicle stopped according to the gradient of the road surface, and determining the AVH control pressure according to the vehicle speed when the driver's braking pressure is lower than the target braking pressure. Determines a pressure rise slope, generates the AVH control pressure according to the pressure rise slope, supplies the AVH control pressure to each wheel to increase the wheel pressure to the target braking pressure, and EPB (Electronic Parking Brake Brake) during AVH control ) When fastening occurs, it is determined that the AVH control release condition is satisfied, and when the AVH control release condition is satisfied, pitching motion due to pitch direction twist of the vehicle is determined from longitudinal acceleration of the vehicle, and the pitching motion Accordingly, an automatic vehicle hold control method may be provided, which includes determining a pressure drop slope of the AVH control pressure when releasing the AVH control, and releasing the AVH control by reducing the AVH control pressure according to the pressure drop slope. .

The present invention can minimize jerk by applying an appropriate pressure control pattern for each situation when the braking pressure is generated by satisfying the AVH control entry condition or the braking pressure is released by satisfying the AVH control release condition.

1 shows a vehicle to which an automatic vehicle holding system according to an embodiment is applied.
2 shows a configuration diagram of an electronic brake system applied to an automatic vehicle hold system according to an embodiment.
3 shows a configuration diagram of an electronic parking brake applied to an automatic vehicle hold system according to an embodiment.
4 shows a control block diagram of an automatic vehicle hold system according to an embodiment.
5 shows a pressure control pattern when braking pressure is increased after AVH control is entered in an automatic vehicle hold system according to an embodiment.
6 shows a pressure control pattern when AVH control is released by engaging an EPB in an automatic vehicle holding system according to an embodiment.

Like reference numbers designate like elements throughout the specification. This specification does not describe all elements of the embodiments, and general content or overlapping content between the embodiments in the technical field to which the disclosed invention belongs is omitted. The term 'unit, module, member, or block' used in the specification may be implemented as software or hardware, and according to embodiments, a plurality of 'units, modules, members, or blocks' may be implemented as one component, It is also possible that one 'part, module, member, block' includes a plurality of components.

Throughout the specification, when a part is said to be “connected” to another part, this includes not only the case of being directly connected but also the case of being indirectly connected, and the indirect connection includes being connected through a wireless communication network. do.

In addition, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Throughout the specification, when a member is said to be located “on” another member, this includes not only a case where a member is in contact with another member, but also a case where another member exists between the two members.

Terms such as first and second are used to distinguish one component from another, and the components are not limited by the aforementioned terms. Expressions in the singular number include plural expressions unless the context clearly dictates otherwise.

In each step, the identification code is used for convenience of description, and the identification code does not explain the order of each step, and each step may be performed in a different order from the specified order unless a specific order is clearly described in context. there is.

1 shows a vehicle to which an automatic vehicle holding system according to an embodiment is applied.

Referring to FIG. 1 , a vehicle may include an electronic brake system 1 , an electronic parking brake system 2 , an AVH system 3 , and the like.

The electronic brake system 1 can control a brake device in response to a driver's braking intention through a brake pedal and/or slip of wheels.

The electronic brake system 1 may be an anti-lock braking system (ABS) capable of temporarily releasing braking of a wheel in response to wheel slip detected during vehicle braking. In addition, the electronic brake system 1 is a vehicle attitude control device (electronic stability control device) capable of selectively releasing braking of a wheel in response to oversteering and/or understeering detected during vehicle steering. ; ESC). In addition, the electronic brake system 10 may be a traction control system (TCS) capable of temporarily braking a wheel in response to wheel slip detected while driving the vehicle.

The electronic parking brake system 2 increases the torque generated from the electric motor through a reducer to generate a clamping force required for parking by a mechanical structural device inside the caliper.

The AVH system 3 can communicate with various systems of the vehicle, such as the electronic brake system 1 and the electronic parking brake system 2, through a vehicle communication network. For example, systems exchange data via Ethernet, Media Oriented Systems Transport (MOST), Flexray, Controller Area Network (CAN), Local Interconnect Network (LIN), etc. can receive

2 shows a configuration diagram of an electronic brake system applied to an automatic vehicle hold system according to an embodiment.

Referring to FIG. 2, the electronic brake system 1 includes a master cylinder 20 provided in a hydraulic block 30 and pressurizing and discharging a pressurized medium accommodated therein by operating a brake pedal 10, and a hydraulic pressure therein. A hydraulic block 30 provided with a plurality of flow passages and valves for adjusting, a wheel brake 40 coupled to the hydraulic block 30 and provided on each wheel, and a brake pedal coupled to the hydraulic block 30 ( A hydraulic pressure supply device 50 that generates hydraulic pressure by driving by an electrical signal corresponding to the displacement of 10) and supplies the generated hydraulic pressure to each wheel brake 40 provided on each wheel, and the master cylinder 20 or hydraulic pressure supply A hydraulic control unit 60 for controlling the flow of hydraulic pressure transmitted to each wheel brake 40 by the device 50 may be included.

The hydraulic block 30 has a hexahedron shape and may serve to transfer hydraulic pressure to the wheel brake 40 provided on each wheel.

The hydraulic block 30 may have a flow path formed therein to control the hydraulic pressure transmitted to the wheel brake 40, and a plurality of valves may be installed in appropriate positions.

A master cylinder 20 may be provided inside the hydraulic block 30 .

The hydraulic pressure supply device 50 includes a motor 51 coupled to the side of the hydraulic block 30 and a slave cylinder 52 pressurized by a power conversion unit coupled with the motor 51 to convert rotational force into linear motion. can include

The slave cylinder 52 is installed in the hydraulic block 30 separately from the master cylinder 20 and moves back and forth by the rotational force of the motor 51 to generate hydraulic pressure, and the slave piston 52a It may include a hydraulic chamber (52b) pressurized by. At this time, a rack gear may be formed on a part of the slave piston 52a so that the slave piston 52a linearly moves through the power conversion unit.

The hydraulic pressure supply device 50 may be provided with various types and structures of devices.

The hydraulic control unit 60 may receive hydraulic pressure from the master cylinder 20 or the hydraulic pressure supply device 50 and control hydraulic pressure transmitted to the wheel brake 40 .

The hydraulic control unit 60 may include a solenoid valve that is electronically opened and closed.

The electronic brake system equipped with the above components can generate hydraulic pressure by operating the hydraulic pressure supply device 50 during braking control. For example, hydraulic pressure can be generated in the hydraulic pressure chamber 52b by moving the slave piston 52a by the operation of the motor 51 of the hydraulic pressure supply device 50 . The hydraulic pressure generated by the hydraulic pressure supply device 50 may be supplied to the wheel brake 40 through the hydraulic control unit 60 to generate braking force on the wheels. At this time, the pressure of the wheel brake 40 of the wheel may be increased, decreased, or maintained by driving the hydraulic pressure supply device 50 and the hydraulic control unit 60 according to the required target pressure.

3 shows a configuration diagram of an electronic parking brake applied to an automatic vehicle hold system according to an embodiment.

Referring to FIG. 3, the electronic parking brake 2 includes a carrier 110 in which a pair of pad plates 111 and 112 are installed to be retractable so as to press the brake disk 100 rotating together with the rear wheel of the vehicle, and the carrier ( 110) and a caliper housing 120 provided with a cylinder 123 in which the piston 121 is installed so that the piston 121 can move forward and backward by braking hydraulic pressure, and a power conversion unit 130 for pressurizing the piston 121, A motor actuator 140 that transmits rotational force to the power conversion unit 130 using the motor (M) 141 may be included.

The pair of pad plates 111 and 112 are distinguished by an inner pad plate 111 disposed in contact with the piston 121 and an outer pad plate 112 disposed in contact with the finger portion 0122 of the caliper housing 120. . The pair of pad plates 111 and 112 are installed on the carrier 110 fixed to the vehicle body so that they can advance and retreat toward both sides of the brake disk 100 . In addition, a brake pad 113 is attached to one surface of each of the pad plates 111 and 112 facing the brake disk 100 .

The caliper housing 120 is slidably installed on the carrier 110 . More specifically, the caliper housing 120 has a power conversion unit 130 installed at its rear, a cylinder 123 built in so that the piston 121 can advance and retreat, and an outer pad plate 112 at the front. Operate It includes a finger portion 122 formed to be bent in a downward direction so as to The finger portion 122 and the cylinder 123 are integrally formed.

The piston 121 is provided in a cylindrical shape with a cup shape inside and is inserted so as to be slidable in the cylinder 123. The piston 121 presses the inner pad plate 111 toward the brake disk 100 by the axial force of the power conversion unit 130 receiving the rotational force of the motor actuator 140 . Accordingly, when the axial force of the power conversion unit 130 is applied, the piston 121 advances toward the inner pad plate 111 and presses the inner pad plate 111, and the caliper housing 120 moves the piston 121 by the reaction force. ), and the finger portion 122 presses the outer pad plate 112 toward the brake disk 100, thereby performing braking.

The EPB actuators 130 and 140 may include a power conversion unit 130 and a motor actuator 140 .

The power conversion unit 130 may serve to press the piston 121 toward the inner pad plate 111 by receiving rotational force from the motor actuator 140 .

The power conversion unit 130 may include a nut member 131 installed to be disposed within the piston 121 and in contact with the piston 121, and a spindle member 135 screwed to the nut member 131. .

The nut member 131 may be disposed in the piston 121 in a rotation-restricted state and screwed to the spindle member 135 .

The nut member 131 includes a head portion 132 provided to contact the piston 121, and a coupling portion 133 extending from the head portion 132 and having a female thread formed on the inner circumferential surface so as to be screwed with the spindle member 135 can be made with

The nut member 131 moves in a forward or backward direction according to the direction of rotation of the spindle member 135 and may serve to pressurize and release the pressurization of the piston 121 . At this time, the forward direction may be a moving direction in which the nut member 131 approaches the piston 121 . The backward direction may be a direction in which the nut member 131 moves away from the piston 121 . In addition, the forward direction may be a movement direction in which the piston 121 approaches the brake pad 113 . The backward direction may be a direction in which the piston 121 moves away from the brake pad 113 .

The spindle member 135 includes a shaft portion 136 that passes through the rear portion of the caliper housing 120 and rotates by receiving the rotational force of the motor actuator 140, and a flange portion 137 extending radially from the shaft portion 136 can include One side of the shaft portion 136 is rotatably installed through the rear side of the cylinder 123, and the other side thereof may be disposed within the piston 121. At this time, one side of the shaft portion 136 penetrating the cylinder 123 is connected to the output shaft of the reducer 142 to receive rotational force of the motor actuator 140 .

The motor actuator 140 may include a motor 141 and a reducer 142 .

The motor 141 may pressurize or depressurize the piston 121 by rotating the spindle member 135 to move the nut member 131 back and forth.

The reduction gear 142 may be provided between the output side of the motor 141 and the spindle member 135 .

By having the above configuration, the electronic parking brake 2 can pressurize the piston 121 by moving the nut member 131 by rotating the spindle member 135 in one direction using the motor actuator 140 when the EPB is engaged. . The piston 121 pressed by the movement of the nut member 131 presses the inner pad plate 111 to bring the brake pad 113 into close contact with the brake disk 100, thereby generating a fastening force. .

In addition, when the EPB is released, the electronic parking brake 2 rotates the spindle member 135 in the opposite direction using the motor actuator 140, so that the nut member 131 pressed against the piston 121 can move backward. Pressurization of the piston 121 may be released by the retreating movement of the nut member 131 . When the pressurization of the piston 121 is released, the brake pad 113 is separated from the brake disk 100, thereby releasing the clamping force generated by releasing the locking operation.

4 shows a control block diagram of an automatic vehicle hold system according to an embodiment.

Referring to FIG. 4 , the AVH system 3 may include a control unit 200 for overall control of the AVH system 3 and an AVH switch 210 electrically connected to the control unit 200 .

The AVH switch 210 is provided to be turned on or off by the driver.

The AVH switch 210 transmits a signal corresponding to an AVH operation command when turned on and a signal corresponding to an AVH operation release command when turned off to the control unit 200 .

The controller 200 may be referred to as an Electronic Control Unit (ECU).

The controller 200 may include a processor 201 and a memory 202 .

The controller 200 may include one or more processors 201 . One or more processors 201 included in the control unit 200 may be integrated into one chip or may be physically separated. Also, the processor 201 and the memory 202 may be implemented as a single chip.

The memory 202 may store programs for processing or control of the processor 201 and various data for operating the electronic parking brake system.

The memory 202 includes not only volatile memory such as S-RAM and D-RAM, but also flash memory, ROM (Read Only Memory), Erasable Programmable Read Only Memory (EPROM), and the like. of non-volatile memory.

The processor 201 may control the overall operation of the AVH system 3.

The control unit 200 having the above configuration activates or deactivates the AVH function in response to an operation signal of the AVH switch 210 or an operation signal generated by a program related to AVH operation.

The controller 200 may receive vehicle speed, master cylinder pressure, longitudinal acceleration, brake pedal information, accelerator pedal information, and EPB engagement information from various systems of the vehicle through a vehicle communication network provided to communicate with various systems of the vehicle. .

The controller 200 may directly receive the vehicle speed or determine the vehicle speed from four wheel speeds. The control unit 200 may determine the current braking pressure during AVH control through the pressure of the master cylinder. The control unit 200 may determine a road surface slope, vehicle pitch information, and the like from the longitudinal acceleration of the vehicle. The pitch information of the vehicle may be determined using a sensor value of a longitudinal acceleration sensor and a sensor value of a gyro sensor. The controller 200 may determine the driver's will to brake based on brake pedal information. The controller 200 may determine the driver's will to accelerate based on accelerator pedal information. The controller 200 may determine whether the electronic parking brake 2 is engaged or not based on the EPB engagement information.

When the control unit 200 generates AVH braking pressure by satisfying the AVH control entry condition or releases the AVH braking pressure by satisfying the AVH control release condition, the control unit 200 controls the electronic brake system 1 to apply an appropriate pressure control pattern for each situation. Minimize jerk.

5 shows a pressure control pattern when braking pressure is increased after AVH control is entered in an automatic vehicle hold system according to an embodiment.

Referring to FIG. 5 , AVH non-operation and AVH operation are distinguished according to the state of the AVH switch 210 .

When the AVH switch 210 is switched from off to on at time t1, AVH control is switched from inactive to active.

When the AVH switch 210 is turned on, it is determined whether the driver's braking pressure and each wheel speed satisfy the AVH control entry condition.

When the AVH control entry condition is satisfied, AVH control is performed to generate AVH control pressure by activating the electronic brake system 1 so as to maintain the stopped state of the vehicle.

If the speed of the four wheels of the vehicle is lower than 0.5 kph and the braking pressure of the driver is higher than the minimum AVH control entry pressure, which is a preset pressure for determining the AVH control entry, it may be determined that the AVH control entry condition is satisfied.

If the AVH control entry condition is satisfied, the gradient of the road surface on which the vehicle is stopped is estimated from the longitudinal acceleration of the vehicle, and the target braking pressure, which is the target braking pressure for each gradient to keep the vehicle stationary, is determined according to the estimated road surface gradient . The higher the slope of the road surface, the higher the target braking pressure.

If the driver's braking pressure is higher than the target braking pressure, AVH control pressure is generated by controlling the electronic parking brake system 1 so that the wheel pressure maintains the target braking pressure when the driver releases the brake pedal, thereby generating AVH control pressure for each wheel. supply to

Meanwhile, when the driver's braking pressure is lower than the target braking pressure, the electronic parking brake system 1 is controlled to increase the wheel pressure to the target braking pressure to generate AVH control pressure and supply it to each wheel.

As described above, when the driver's braking pressure is lower than the target braking pressure, the AVH control pressure is supplied to each wheel to increase the wheel pressure to the target braking pressure. If the pressure is increased to , a jerk may occur when the vehicle comes to a complete stop. That is, when the AVH control pressure is increased with a certain slope at the time point t1, a jerk occurs due to the rapid pressure increase, as can be seen from the longitudinal acceleration indicated by the dotted line. In the past, since the pressure is increased at a constant slope regardless of the vehicle speed, the pressure is rapidly increased and jerk occurs before the vehicle comes to a complete stop.

However, in this situation, the present invention minimizes the jerk by applying an appropriate pressure boosting pattern with reference to the vehicle speed. To this end, the pressure increase gradient of the AVH control pressure is controlled relatively gently, as shown in the solid line, so that the pressure is increased smoothly (or pressure is increased slowly) until the vehicle comes to a complete stop. It controls the pressure rise gradient of pressure relatively rapidly. That is, the pressure increase rate of the AVH control pressure is controlled differently before and after a complete stop, but by controlling the pressure increase rate before a complete stop to be lower than that after a complete stop, the pressure can be increased smoothly until a complete stop, and after a complete stop. can be rapidly increased in pressure, preventing the occurrence of jerk.

6 shows a pressure control pattern when AVH control is released by engaging an EPB in an automatic vehicle holding system according to an embodiment.

Referring to FIG. 6 , if AVH control release conditions are satisfied during AVH control, AVH control is released.

During AVH control, when the driver opens the door or engages the gearbox in P, the EPB engages at time t1 and the AVH control is released at time t2.

Conventionally, when the AVH control is released, the AVH control pressure is reduced with a certain slope as indicated by the dotted line. In this case, when the AVH control is released after the EPB is engaged on the slope, the vehicle stopped with the braking force of the four wheels stops with only the two rear wheels, and jerk may occur due to twisting of the vehicle in the pitch direction. That is, when the AVH control pressure is reduced at a certain slope at the time t1, as can be seen from the longitudinal acceleration of the dotted line, jerk occurs because the EPB engagement of the rear wheel causes pitching motion by twisting the pitch direction of the vehicle.

However, the present invention minimizes the jerk by applying a very long fade-out time of the AVH control pressure in this situation. To this end, the pressure drop gradient of the AVH control pressure is controlled relatively gently as shown in the solid line so that the pressure is reduced slowly when there is a pitching motion due to the equilibrium of the moment of the vehicle, and when there is no pitching motion, the AVH is controlled as shown in the solid line so that the pressure is quickly reduced. It controls the pressure drop slope relatively rapidly. That is, the pressure reduction rate of the AVH control pressure is controlled differently between when there is pitching motion and when there is no pitching motion, but the pressure reduction rate when there is pitching motion is lower than that when there is no pitching motion, thereby controlling the pitching motion. When there is a pressure, it can be reduced slowly, and when there is no pitching motion, it can be increased quickly, preventing the occurrence of jerk.

As described above, the present invention can minimize the driver's jerk by applying an appropriate pressure control pattern for each situation when the AVH braking pressure is generated by satisfying the AVH control entry condition or the AVH braking pressure is released by satisfying the AVH control release condition. can reduce discomfort.

Meanwhile, the aforementioned control unit and/or its components may include one or more processor/microprocessor(s) combined with a computer readable recording medium storing computer readable code/algorithm/software. The processor/microprocessor(s) may execute the computer readable code/algorithm/software stored in a computer readable recording medium to perform the aforementioned functions, operations, steps, and the like.

The above-described control unit and/or its components may further include a memory implemented as a computer-readable non-transitory recording medium or a computer-readable temporary recording medium. The memory may be controlled by the above-described control unit and/or its components, configured to store data transmitted to or received from the above-described control unit and/or its components, or by the above-described control unit and/or its components. It may be processed or configured to store data to be processed.

The disclosed embodiment can also be implemented as computer readable code/algorithm/software on a computer readable recording medium. The computer-readable recording medium may be a computer-readable non-transitory recording medium such as a data storage device capable of storing data that can be read by a processor/microprocessor. Examples of computer-readable recording media include hard disk drives (HDD), solid state drives (SSD), silicon disk drives (SDD), read-only memory (ROM), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices. etc.

200: control unit 201: processor
202: memory 210: AVH switch

Claims (10)

When the AVH (Auto Vehicle Hold) switch is turned on, it is determined whether the driver's braking pressure and vehicle speed satisfy the AVH control entry conditions,
If the AVH control entry condition is satisfied, the gradient of the road surface on which the vehicle is stopped is estimated from the longitudinal acceleration of the vehicle;
Determining a target braking pressure for maintaining the vehicle stop according to the road surface slope;
When the driver's braking pressure is lower than the target braking pressure, determining a pressure rising slope of the AVH control pressure according to the vehicle speed;
generating the AVH control pressure according to the pressure rise gradient;
and supplying the AVH control pressure to each wheel to increase the wheel pressure to the target braking pressure. According to claim 1,
Determining the pressure rise slope of the AVH control pressure,
and determining a pressure increase slope of the AVH control pressure differently when the vehicle is before a complete stop and after a complete stop. According to claim 2,
Determining the pressure rise slope of the AVH control pressure,
and determining a pressure increase slope of the AVH control pressure before the vehicle is completely stopped than a pressure increase slope of the AVH control pressure when the vehicle is completely stopped. According to claim 1,
Determining the pressure rise slope of the AVH control pressure,
and determining a pressure increasing slope of the AVH control pressure to increase relatively gently when the vehicle is completely stopped and to increase relatively rapidly when the vehicle is completely stopped. . According to claim 1,
Determining the pressure rise slope of the AVH control pressure,
and determining a pressure increasing slope of the AVH control pressure to be increased relatively slowly when the vehicle is before a complete stop and to be increased relatively quickly when the vehicle is completely stopped. When the EPB (Electronic Parking Brake) is engaged during AVH (Auto Vehicle Hold) control, it is determined that the AVH control release condition is satisfied.
When the AVH control release condition is satisfied, pitching motion due to pitch direction twist of the vehicle is determined from longitudinal acceleration of the vehicle;
Determine a pressure drop gradient of an AVH control pressure when the AVH control is released according to the pitching motion;
and releasing the AVH control by reducing the AVH control pressure according to the pressure dropping slope. According to claim 6,
Determining the pressure drop slope of the AVH control pressure,
and determining a pressure drop slope of the AVH control pressure differently depending on whether or not the vehicle has a pitch motion. According to claim 7,
Determining the pressure drop slope of the AVH control pressure,
and determining a pressure drop slope of the AVH control pressure when the pitch motion of the vehicle is present is lower than a pressure drop slope of the AVH control pressure when there is no pitch motion. According to claim 1,
Determining the pressure drop slope of the AVH control pressure,
and determining a pressure drop slope of the AVH control pressure to decrease relatively slowly when the vehicle has a pitch motion and to decrease relatively quickly when the vehicle does not have a pitch motion. When the AVH (Auto Vehicle Hold) switch is turned on, it is determined whether the driver's braking pressure and vehicle speed satisfy the AVH control entry conditions,
If the AVH control entry condition is satisfied, the gradient of the road surface on which the vehicle is stopped is estimated from the longitudinal acceleration of the vehicle;
Determining a target braking pressure for maintaining the vehicle stop according to the road surface slope;
When the driver's braking pressure is lower than the target braking pressure, determining a pressure rise gradient of the AVH control pressure according to the vehicle speed;
generating the AVH control pressure according to the pressure rise gradient;
supplying the AVH control pressure to each wheel to increase the wheel pressure to the target braking pressure;
If the EPB (Electronic Parking Brake) connection occurs during AVH control, it is determined that the AVH control release condition is satisfied.
When the AVH control release condition is satisfied, pitching motion due to pitch direction twist of the vehicle is determined from longitudinal acceleration of the vehicle;
Determine a pressure drop gradient of an AVH control pressure when the AVH control is released according to the pitching motion;
and releasing the AVH control by reducing the AVH control pressure according to the pressure dropping slope.

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