KR20200084550A - Apparatus and method for controlling brake of a vehicle - Google Patents

Abstract

The present invention relates to a braking apparatus and a braking method for performing ABS pitch motion cooperative control by using a garage sensor included in an ECS. According to an embodiment of the present invention, a braking apparatus for a vehicle comprises: a vehicle height sensor for detecting a vehicle height value as the height of the vehicle with respect to the ground; a longitudinal acceleration sensor for detecting the longitudinal acceleration of the vehicle; a wheel speed sensor installed inside the wheels of the vehicle to detect the rotational speed of the wheels of the vehicle; a determination unit which determines whether a condition is satisfied that at the time of sudden braking of the vehicle, the time of the state in which the longitudinal acceleration is more than or equal to a first reference value, variance in the acceleration of the vehicle is more than or equal to a second reference value, and the vehicle height value is more than or equal to a third reference value, exceeds a preset time; and a pitch motion control unit which extracts the vertical load of a front wheel corresponding to the vehicle height value from a table in which the vertical loads of the front wheel and a rear wheel corresponding to one or more vehicle height values are stored, and replaces the extracted vertical load with the target braking pressure of the front wheel, if the condition is satisfied, and the pitch motion control when the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value, as a result of obtaining the determination unit. Therefore, the braking apparatus can increase the performance of ABS pitch motion cooperative control.

Description

Brake device and method of vehicle{APPARATUS AND METHOD FOR CONTROLLING BRAKE OF A VEHICLE}

The present invention relates to a braking device and a braking method for performing an anti-brake system (ABS) pitch motion cooperative control using a height sensor included in an electronic control suspension (ECS).

In general, the vehicle is equipped with an electronic control system such as ABS, and the ABS (Anti-Lock Brake System) detects the slippage of the wheel that occurs when braking on a slippery road such as snow, rain, or sudden braking. By adjusting, it is a device that prevents slipping due to locking of the wheels and secures directional stability and maneuverability when braking. Such ABS is vulnerable to pitch motion during sudden braking. The dynamic load is rapidly applied to the front wheel, and the braking force of the rear wheel decreases, and immediately afterwards, some of the load moves back to the rear wheel due to the repulsive force caused by the pitch facet. Due to this, the braking distance loss and braking feeling are reduced.

The above-mentioned background technology is technical information acquired by the inventor for the derivation of the present invention or acquired in the derivation process of the present invention, and is not necessarily a known technology disclosed to the general public prior to the filing of the present invention.

Domestic Patent Publication No. 2015-0062268

The present invention has been devised to solve the above-mentioned problems and/or limitations, and an object of the present invention according to one aspect is to improve the performance of ABS pitch motion cooperative control by using a height sensor included in ECS.

A braking device for a vehicle according to an embodiment of the present invention includes: a height sensor for detecting a height value as a height with respect to the ground of a vehicle; A longitudinal acceleration sensor that detects the longitudinal acceleration of the vehicle; A wheel speed sensor installed inside the wheel of the vehicle to detect a rotational speed with respect to the wheel of the vehicle; When the vehicle is braked rapidly, a condition for whether the longitudinal acceleration is greater than or equal to a first reference value, an amount of change in acceleration of the vehicle is greater than or equal to a second reference value, and a state in which the vehicle height value is greater than or equal to a third reference value exceeds a preset time A judging unit that determines whether it is satisfied; And the result of the determination of the determination unit, when the condition is satisfied, the target braking pressure of the front wheel is extracted by extracting the vertical load of the front wheel corresponding to the height value from a table in which the vertical loads of the front and rear wheels corresponding to one or more height values are pre-stored And a pitch motion control unit that performs pitch motion control when the braking pressure of the front wheel exceeds a target braking pressure of the front wheel multiplied by a specific value.

The garage sensor may be included in an electronic control suspension (ECS).

When the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value, the control unit may perform the pitch motion control for gradually increasing the braking pressure hold and braking pressure increase for a predetermined time.

The control unit may perform the pitch motion control until the braking pressure of the front wheel becomes less than a target braking pressure of the front wheel multiplied by a specific value.

The control unit may stop pitch motion control and perform ABS control when the braking pressure of the front wheel is less than a target braking pressure of the front wheel multiplied by a specific value.

A braking method for a vehicle according to an embodiment of the present invention includes: detecting, by a height sensor, a height value as a height with respect to the ground of the vehicle; Detecting a longitudinal acceleration of the vehicle by a longitudinal acceleration sensor; A step of detecting a rotational speed with respect to a wheel of the vehicle by being installed inside the wheel of the vehicle by a wheel speed sensor; At the time of sudden braking of the vehicle, by the determination unit, the longitudinal acceleration is equal to or greater than the first reference value, and the amount of change with respect to acceleration as the amount of change in the rotational speed of the vehicle is greater than or equal to the second reference value, and the height of the vehicle is greater than or equal to the third reference value. Determining whether the condition satisfies a condition as to whether the state exceeds a predetermined time; And a pitch motion controller extracts the vertical load of the front wheel corresponding to the vehicle height value from a table in which the vertical loads of the front and rear wheels corresponding to one or more vehicle height values are pre-stored when the condition of the determination unit is satisfied. It may include a step of performing pitch motion control when the target braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value.

The height sensor may be included in an electronic control suspension (ECS) to detect the height value.

In the step of performing the pitch motion control, when the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value, the pitch motion control for gradually increasing the braking pressure hold and braking pressure increase for a certain period of time It may include a step of performing.

The method may perform the pitch motion control until the braking pressure of the front wheel becomes less than a target braking pressure of the front wheel multiplied by a specific value.

The method may stop pitch motion control and perform ABS control when the braking pressure of the front wheel is less than a target braking pressure of the front wheel multiplied by a specific value.

In addition to this, other methods for implementing the present invention, other systems, and computer programs for executing the methods may be further provided.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

According to embodiments, the objective is to improve the performance of the ABS pitch motion cooperative control using the height sensor included in the ECS.

In addition, it is possible to improve ABS performance and robustness on a 3D road surface.

The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a view schematically illustrating a braking device for a vehicle according to an embodiment of the present invention.
FIG. 2 is a view illustrating a look-up table for a pitch-vertical load stored in a memory among the braking devices of the vehicle illustrated in FIG. 1.
FIG. 3 is a diagram showing an initial trace diagram during sudden braking among the braking devices of the vehicle shown in FIG. 1.
4 is a flowchart illustrating a braking method of a vehicle according to an embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will be clarified by referring to embodiments described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments presented below, but may be implemented in various different forms, and should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. . The embodiments presented below are provided to complete the disclosure of the present invention and to fully inform the scope of the invention to those skilled in the art to which the present invention pertains. In the description of the present invention, when it is determined that a detailed description of known technologies related to the present invention may obscure the subject matter of the present invention, the detailed description will be omitted.

Terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as “include” or “have” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and that one or more other features are present. It should be understood that the existence or addition possibilities of fields or numbers, steps, operations, components, parts or combinations thereof are not excluded in advance. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from other components.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings, and in describing with reference to the accompanying drawings, identical or corresponding components are assigned the same reference numbers, and redundant description thereof is omitted. I will do it.

1 is a view schematically illustrating a braking device for a vehicle according to an embodiment of the present invention, and FIG. 2 is a lookup table for a pitch-vertical load stored in a memory among the braking devices for a vehicle shown in FIG. 1 It is a diagram shown to illustrate. Referring to FIG. 1, the braking device 1 of a vehicle may include an ECS 100, an ESC 200, and wheels (front R/L, rear R/L, 310,...,340).

The electronic control suspension (ECS) 100 includes a variable damping force damper equipped with various sensors (not shown), an electronic control valve (not shown) and an actuator (not shown), and the driving situation of the vehicle (straight/turn/acceleration/deceleration). According to this, it is possible to improve ride comfort and handling performance by controlling the damping force of the front and rear wheels. For example, each damper attenuation force control according to the road surface situation when going straight, damper attenuation force control is performed to control roll motion when turning, and sensor detection values for controlling pitch motion during sudden acceleration/braking are ECS (100 ). In this embodiment, the ECS 100 may include the height sensor 110, and the height value detected by the height sensor 110 may be output to the ECS 100 to control the pitch motion during rapid acceleration/braking. have. The height sensor 110 may detect a height value as a height with respect to the ground of the vehicle, that is, a pitch value, a pitch amount, or a pitch angle.

The electronic stability control (ESC) 200 is a wheel (front wheel R/L, rear wheel R/L) 310, which enables the brake of a wheel that requires braking to be selectively activated in an unstable situation during vehicle acceleration or braking or cornering. ..,340) to maintain the stability of the vehicle.

In this embodiment, the ESC 200 may include a sensor unit 210, a collection unit 220, a condition determination unit 230, a pitch motion control unit 240, a memory 250, and a braking device unit 260. have. In this embodiment, the sensor unit 210 may include a steering angle sensor 211, a longitudinal acceleration sensor 212, a lateral acceleration sensor 213, a wheel speed sensor 214, and a yaw rate sensor 215. .

The steering angle sensor 211 may detect a steering angle (column input angle) according to the driver's steering wheel operation. The steering angle sensor 211 is mounted on a lower end of a steering wheel (not shown), and can detect the steering speed, steering direction, and steering angle of the steering wheel.

The longitudinal acceleration sensor 212 may detect acceleration in the X-axis direction (longitudinal direction) when the moving direction of the vehicle is the X-axis direction.

When the moving direction of the vehicle is the X-axis direction, the lateral acceleration sensor 213 may detect the lateral acceleration of the vehicle by setting the vertical axis (Y-axis) direction of the moving direction as the lateral direction.

Here, the longitudinal acceleration sensor 212 and the lateral acceleration sensor 213 may be acceleration sensors that detect acceleration of the vehicle. The acceleration sensor is a device that detects a change in speed per unit time, and detects dynamic forces such as acceleration, vibration, and shock, and can be detected using the principles of inertia, electric deformation, and gyro.

The wheel speed sensor 214 is installed inside the wheel of the vehicle to detect the rotational speed of the wheel of the vehicle.

The yaw rate sensor 215 may be installed at the center of the vehicle, and may detect the yaw rate value in real time. The yaw rate sensor 215 has a cesium crystal element inside the sensor, and when the vehicle rotates while moving, the cesium crystal element itself rotates to generate a voltage, based on the generated voltage. Can be detected.

The collection unit 220 may collect various sensor values detected by the sensor unit 210, and also collect pitch values output from the garage sensor 110. The conventional ABS recognizes a sudden pitch motion using the longitudinal acceleration sensor 212 during sudden braking, and at this time, limits the pressure increase of the front wheel to prevent the vehicle's dynamic load from being rapidly forward. However, in vehicles with very strong front and rear suspension stiffness, the responsiveness of the pitch motion is very fast and the response speed of the longitudinal acceleration sensor 212 is difficult to follow, and in a 3D-shaped circuit (for example, a human-made circuit), the slope/ Sudden braking is required in an upward slope, etc., and the longitudinal acceleration sensor 212 may be distorted depending on the inclination. On the other hand, if the garage sensor 110 is used, the current pitch amount can be accurately known, and accordingly, the precise vertical load of the vehicle can be known, thereby enabling precise ABS braking control. Since the garage sensor 110 controls the suspension compared to the longitudinal acceleration sensor 212, there is an advantage that the reaction speed is fast.

The condition determining unit 230 may determine a condition for performing the pitch motion control based on the detection values of the sensors collected by the collecting unit 220. The condition determination unit 230 in the braking state to decelerate the vehicle speed, the longitudinal acceleration detected from the longitudinal acceleration sensor 212 is greater than or equal to the first reference value, and the amount of change in acceleration of the vehicle is greater than or equal to the second reference value, and the vehicle height value It can be determined whether a condition that is greater than or equal to the third reference value exceeds a predetermined time. Here, the amount of change in acceleration of the vehicle is the amount of change in acceleration detected by the acceleration sensor including the longitudinal acceleration sensor 212 and the lateral acceleration sensor 213, and the wheel speed sensor 214 detects the wheel of the vehicle. An acceleration that differentiates the rotational speed may be calculated, and any one of the change amount of the acceleration may be included. In addition, the first reference value to the third reference value are arbitrary values, and their values may be different depending on the type of vehicle.

The pitch motion control unit 240, as a result of the condition determination by the condition determination unit 230, in the braking state to decelerate the vehicle speed, the longitudinal acceleration detected from the longitudinal acceleration sensor 212 is greater than or equal to the first reference value, and the vehicle When the condition for whether the state where the acceleration change amount is equal to or greater than the second reference value and the height value equal to or greater than the third reference value exceeds a preset time period, pitch motion control may be started.

The pitch motion control unit 240 may extract a target braking pressure using a lookup table pre-stored in the memory 250 for pitch motion control. FIG. 2 is a view for explaining a lookup table pre-stored in the memory 250, and the lookup table includes vertical load values of front and rear wheels corresponding to the pitch value (pitch angle) of the vehicle detected by the garage sensor 110. It can be pre-stored. The pitch-vertical load stored in the look-up table may be measured and stored in advance using a sensor device such as a six-minute hydrometer, and input as a parameter according to vehicle logic. Knowing the current pitch value, it is possible to know how much the vehicle has been moved, so it is possible to predict the vertical load of the front and rear wheels. The pitch motion control unit 240 may set the target braking pressure based on the vertical load value of the front wheel corresponding to the pitch value (pitch angle) of the vehicle detected by the garage sensor 110. When braking, the vertical load is proportional to the wheel locking value, so the target braking pressure can be set in proportion to the vertical load depending on the vehicle model.

The pitch motion control unit 240 performs pitch motion control when the braking pressure of the current front wheel calculated from the pitch value exceeds the target braking pressure of the front wheel multiplied by a specific value, and the braking pressure of the current front wheel calculated from the pitch value is specified If it is less than the target braking pressure of the front wheel multiplied by the value, the pitch motion control may be stopped, the pitch motion control may be stopped, and the ABS control may be performed. Here, the specific value may be, for example, 0.8, from which the pitch motion control unit 240 may be said to perform pitch motion control when the braking pressure of the current front wheel exceeds 80% of the target braking pressure. In addition, the pitch motion control can perform control to gradually increase the braking pressure hold and the braking pressure increase for a certain period of time, and a certain period of time is tuned differently depending on the vehicle model (for example, 0.1 second or 0.5 second). You can do

The braking device unit 260 may include an ABS unit (not shown) and a plurality of wheel cylinders (not shown), and after performing the pitch motion control from the pitch motion control unit 240, the ABS unit may be used in a rainy or icy road. In case of sudden braking, the wheel is locked so that the wheel cylinder can be controlled to maintain stable stability by maintaining directional stability when the vehicle slides or rotates.

FIG. 3 is a view showing an initial trace diagram during sudden braking among the braking devices of the vehicle shown in FIG. 1. Referring to FIG. 3, when the above-described pitch motion control condition is satisfied in the pitch motion control section 301, pitch motion control for gradually increasing the braking pressure hold and the braking pressure increase for a predetermined period of time may be performed. As the dynamic load is rapidly applied to the front wheel, the braking force of the rear wheel decreases, and immediately afterwards, some of the load moves back to the rear wheel due to the repulsive force by the pitch road surface. When the vehicle is pushed forward by the pitch value and the vertical load on the front wheel increases, control is performed to increase the braking pressure, and if the front load is lifted due to the repulsive force and the vertical load on the front wheel decreases, the control to hold the braking pressure is performed. At this time, the robustness of pitch motion control can be improved. After the pitch motion control, ABS may be started by applying braking pressure to the front wheels R/L, 310,320 and the rear wheels R/L, 330,340.

4 is a flowchart illustrating a braking method of a vehicle according to an embodiment of the present invention. In the following description, parts overlapping with the description of FIGS. 1 to 3 will be omitted.

Referring to FIG. 4, in step S410, the ESC 200 collects detection values from sensors required for the braking device 1 of the vehicle. The ESC 200 may receive detection values from a steering angle sensor 211 to a yaw rate sensor 215, as shown in FIG. 1, and the height sensor 110 included in the ECS 100 It is possible to detect a vehicle height value as a height relative to the ground of the vehicle, that is, a pitch value, a pitch amount or a pitch angle.

In step S420, the ESC 200 determines whether the longitudinal acceleration detected by the longitudinal acceleration sensor 212 is greater than or equal to the first reference value during sudden braking of the vehicle.

In step S430, when the longitudinal acceleration is greater than or equal to the first reference value, the ESC 200 determines whether the state of change in acceleration of the vehicle is greater than or equal to the second reference value and the vehicle height value exceeds the preset time.

In step S440, the ESC 200 is a pitch motion control condition when the longitudinal acceleration is greater than or equal to the first reference value, the amount of change in acceleration of the vehicle is greater than or equal to the second reference value, and the vehicle height value is greater than or equal to the third reference value. It judges that it satisfies and starts pitch motion control. When the pitch motion control is started, the ESC 200 extracts the vertical load of the front wheel corresponding to the current height value from the table in which the vertical loads of the front and rear wheels corresponding to the vehicle height value are pre-stored and replaces it with the target braking pressure of the front wheel.

In step S450, the ESC 200 determines whether the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value.

In step S460, when the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value, the ESC 200 increases the braking pressure hold and braking pressure increase step by step for a period of time. Here, when the vehicle is forwarded by the height value (pitch value) and the front wheel vertical load increases, control is performed to increase the braking pressure, and when the front wheel is lifted due to the repulsive force and the front wheel vertical load decreases, the braking pressure is held. By performing control, it is possible to improve the robustness of the pitch motion control during sudden braking.

In steps S470 and S480, when the braking pressure of the front wheel is less than the target braking pressure of the front wheel multiplied by a specific value, the ESC 200 stops pitch motion control and starts ABS control.

The embodiment according to the present invention described above may be implemented in the form of a computer program that can be executed through various components on a computer, and such a computer program can be recorded on a computer-readable medium. At this time, the medium includes a hard disk, a magnetic medium such as a floppy disk and magnetic tape, an optical recording medium such as CD-ROM and DVD, a magneto-optical medium such as a floptical disk, and a ROM. , Hardware devices specially configured to store and execute program instructions, such as RAM, flash memory, and the like.

Meanwhile, the computer program may be specially designed and configured for the present invention or may be known and available to those skilled in the computer software field. Examples of computer programs may include not only machine language codes produced by a compiler, but also high-level language codes executable by a computer using an interpreter or the like.

The use of the term "above" in the specification (particularly in the claims) of the present invention and similar indication terms may be in both singular and plural. In addition, in the case of describing a range in the present invention, as including the invention to which the individual values belonging to the range are applied (if there is no contrary description), each individual value constituting the range is described in the detailed description of the invention. Same as

Unless explicitly stated or contrary to the steps constituting the method according to the invention, the steps can be done in a suitable order. The present invention is not necessarily limited to the description order of the above steps. The use of all examples or exemplary terms (eg, etc.) in the present invention is merely for describing the present invention in detail, and the scope of the present invention is limited due to the examples or exemplary terms, unless it is defined by the claims. It does not work. In addition, those skilled in the art can recognize that various modifications, combinations, and changes can be configured according to design conditions and factors within the scope of the appended claims or equivalents thereof.

Therefore, the spirit of the present invention is not limited to the above-described embodiment, and should not be determined, and the scope of the spirit of the present invention, as well as the claims to be described later, as well as all ranges that are equivalent to or equivalently changed from the claims Would belong to

100: ECS
110: garage sensor
200: ESC
211: Steering angle sensor
212: longitudinal acceleration sensor
213: lateral acceleration sensor
214: wheel speed sensor
215: yaw rate sensor
220: collection unit
230: condition determination unit
240: pitch motion control
250: memory
260: brake unit
310,...,340: wheels

Claims (10)

A height sensor for detecting a height value as a height with respect to the ground of the vehicle;
A longitudinal acceleration sensor that detects the longitudinal acceleration of the vehicle;
A wheel speed sensor installed inside the wheel of the vehicle to detect a rotational speed with respect to the wheel of the vehicle;
When the vehicle is braked rapidly, a condition for whether the longitudinal acceleration is greater than or equal to a first reference value, an amount of change in acceleration of the vehicle is greater than or equal to a second reference value, and a state in which the vehicle height value is greater than or equal to a third reference value exceeds a preset time A judging unit that determines whether it is satisfied; And
As a result of the determination of the determination unit, when the condition is satisfied, the vertical load of the front wheel corresponding to the height value is extracted from a table in which the vertical loads of the front and rear wheels corresponding to one or more height values are pre-stored to be the target braking pressure of the front wheel. And a pitch motion control unit that performs pitch motion control when the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value. The height sensor of claim 1,
A braking device for a vehicle, included in an electronic control suspension (ECS). The method of claim 1, wherein the control unit,
When the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value, the brake motion control device performs the pitch motion control stepwise increasing braking pressure hold and braking pressure increase for a certain period of time. The method of claim 3, wherein the control unit,
The pitch motion control is performed until the braking pressure of the front wheel becomes less than a target braking pressure of the front wheel multiplied by a specific value, the braking apparatus of the vehicle. The method of claim 1, wherein the control unit,
When the braking pressure of the front wheel is less than the target braking pressure of the front wheel multiplied by a specific value, the vehicle stops the pitch motion control and performs ABS control. Detecting, by a height sensor, a height value as a height with respect to the ground of the vehicle;
Detecting a longitudinal acceleration of the vehicle by a longitudinal acceleration sensor;
A step of detecting a rotational speed with respect to a wheel of the vehicle by being installed inside the wheel of the vehicle by a wheel speed sensor;
At the time of sudden braking of the vehicle, by the determination unit, the longitudinal acceleration is equal to or greater than the first reference value, and the amount of change with respect to acceleration as the amount of change in the rotational speed of the vehicle is greater than or equal to the second reference value, and the height of the vehicle is greater than or equal to the third reference value. Determining whether the condition satisfies a condition as to whether the state exceeds a predetermined time; And
As a result of the determination by the pitch motion control unit, when the above conditions are satisfied, the vertical loads of the front wheels corresponding to the vehicle height values are extracted from a table in which the vertical loads of the front and rear wheels corresponding to one or more vehicle height values are pre-stored. And substituting the target braking pressure of the front wheel and performing a pitch motion control when the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value. The method of claim 6,
The height sensor is included in an electronic control suspension (ECS) to detect the height value, the vehicle braking method. According to claim 1, The step of performing the pitch motion control,
Comprising the step of performing the pitch motion control stepwise increasing the braking pressure hold and braking pressure increase for a period of time, when the braking pressure of the front wheel exceeds the target braking pressure of the front wheel multiplied by a specific value; Braking method. The method of claim 8,
The pitch motion control is performed until the braking pressure of the front wheel becomes less than a target braking pressure of the front wheel multiplied by a specific value, the vehicle braking method. The method of claim 6,
And stopping pitch motion control and performing ABS control when the braking pressure of the front wheel is less than a target braking pressure of the front wheel multiplied by a specific value.

Images