Device and method for controlling a suspension of a vehicle

Abstract

The present invention relates to an apparatus and a method for controlling a suspension of a vehicle. An apparatus for controlling a suspension of a vehicle to improve high-speed running stability of the vehicle includes a sensor that acquires information about a road surface ahead of the vehicle during running of the vehicle, and a controller that derives a height value of the road surface from the information about the road surface, determines a road surface state based on a differential value of the derived height value, predicts a behavior of the vehicle corresponding to the determined road surface state, and controls a damping force of the suspension based on the predicted behavior of the vehicle.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2020-0128304, filed on October 5, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a technology for improving high-speed driving stability by controlling the vehicle's suspension. Background Technology

[0004] The statements in this section are merely background information in relation to the invention and may not constitute prior art.

[0005] Typically, a vehicle's suspension is a device that is connected to the axle and is controlled so that vibrations or impacts from the road are not directly transmitted to the vehicle body during vehicle operation, thereby preventing damage to the vehicle body, occupants, or cargo and safety accidents, and improving the vehicle's ride comfort.

[0006] A suspension system, also known as a suspension device, may include chassis springs to absorb impacts from the road, dampers to control the free vibration of the chassis springs to improve ride comfort, and stabilizer bars to prevent vehicle roll.

[0007] The recently released vehicles are equipped with Electronically Controlled Suspension (ECS), which automatically adjusts the suspension strength according to driving conditions or road surface conditions.

[0008] Electronically controlled suspension (ECS) can detect driving status information (such as vehicle speed, steering angle, vertical acceleration, etc.) and road surface information through various sensors, and can electronically and automatically control the spring constant of the suspension, the damping force of the damper, the attitude of the vehicle body, and the vehicle height according to the road conditions.

[0009] Electronically controlled suspension (ECS) can be classified into active suspension and semi-active suspension. Active suspension controls the movement of the vehicle body by applying external energy to the suspension using actuators, while semi-active suspension uses actuators as auxiliary springs to adjust the damping force.

[0010] Conventional technologies used to control electronically controlled suspension may not be able to accurately identify road conditions (e.g., uphill, downhill, or corrugated) from images of the road surface captured by cameras included in a vehicle traveling at high speeds. Therefore, conventional technologies may not be able to accurately predict vehicle behavior and may not be able to accurately control the damping forces of the suspension.

[0011] The information disclosed in the background section is intended only to enhance the understanding of the background technology of the present invention, and therefore the information it may contain does not constitute any part of the prior art, nor does it constitute any content that the prior art may imply to those skilled in the art. Summary of the Invention

[0012] The present invention is made to solve the above-mentioned problems in the prior art, while fully retaining the advantages achieved by the prior art.

[0013] One aspect of the present invention provides a vehicle suspension control device and method, which determines the height value of the road surface in front of the vehicle based on information about the road surface acquired during high-speed driving, determines the road surface condition (e.g., uphill, downhill, or undulating road) based on the variance and derivative of the height value, predicts the vehicle behavior corresponding to the determined road surface condition, and adjusts the damping force of the suspension based on the predicted vehicle behavior, thereby improving the high-speed driving stability of the vehicle.

[0014] The technical problems solved by this invention are not limited to those described above, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art through the following description. Furthermore, it will be readily understood that aspects and advantages of this invention can be realized by the means set forth in the appended claims and combinations thereof.

[0015] According to one aspect of the invention, an apparatus for controlling a vehicle suspension includes a sensor and a controller, the sensor acquiring information about the road surface in front of the vehicle during vehicle travel, the controller deriving a road surface height value from the road surface information, determining a road surface state based on a derivative of the derived height value, predicting vehicle behavior corresponding to the determined road surface state, and controlling the damping force of the suspension based on the predicted vehicle behavior.

[0016] In an exemplary embodiment of the present invention, the road surface condition may include at least one of an uphill road, a downhill road, or an undulating road.

[0017] In an exemplary embodiment of the present invention, the controller can set the point where the height value of the road surface exceeds the first reference height value and the differential value of the road surface height value exceeds the first reference differential value as the judgment start time point, and can set the point where the height value of the road surface exceeds the second reference height value and the differential value of the road surface height value exceeds the first reference differential value as the judgment confirmation time point. When the distance between the judgment start time point and the judgment confirmation time point is within the reference distance, the road surface can be determined to be an uphill road.

[0018] In an exemplary embodiment of the present invention, when the distance between the determination start time point and the determination confirmation time point exceeds a reference distance, the controller can determine that the road surface is an undulating road.

[0019] In an exemplary embodiment of the invention, the controller can predict vehicle behavior corresponding to an uphill road, and can control the damping force of the suspension based on the predicted vehicle behavior just before entering the uphill road.

[0020] In one exemplary embodiment of the invention, the controller can control the suspension such that the suspension has a damping force that is stiffer than the basic damping force.

[0021] In another embodiment of the present invention, the controller can set the point where the height value of the road surface is less than or equal to the third reference height value and the differential value of the road surface height value is less than or equal to the second reference differential value as the judgment start time point, and can set the point where the height value of the road surface is less than or equal to the fourth reference height value and the differential value of the road surface height value is less than or equal to the second reference differential value as the judgment confirmation time point. When the distance between the judgment start time point and the judgment confirmation time point is within the reference distance, the road surface can be determined to be a downhill road.

[0022] In an exemplary embodiment of the present invention, when the distance between the determination start time point and the determination confirmation time point exceeds a reference distance, the controller can determine that the road surface is an undulating road.

[0023] In another exemplary embodiment of the invention, the controller can predict vehicle behavior corresponding to a downhill road, and can control the damping force of the suspension based on the predicted vehicle behavior just before entering the downhill road.

[0024] In another exemplary embodiment of the invention, the controller can control the suspension such that the suspension has a damping force that is stiffer than the basic damping force.

[0025] In another exemplary embodiment of the invention, the controller can predict vehicle behavior corresponding to undulating roads, and can control the damping force of the suspension based on the predicted vehicle behavior just before entering the undulating road.

[0026] In one exemplary embodiment of the invention, when the vehicle is traveling on an undulating road, the controller can control the damping force of the suspension until the vehicle's bounce and pitch are reduced to a reference value or below.

[0027] In another exemplary embodiment of the present invention, when the variance of the road surface height value exceeds a threshold, the controller may perform a process to determine the road surface state.

[0028] According to another aspect of the present invention, a method for controlling a vehicle suspension includes: during vehicle operation, acquiring information about the road surface in front of the vehicle by a sensor; deriving a road surface height value by a controller from the information about the road surface; determining a road surface state by the controller based on a derivative value of the derived height value; predicting vehicle behavior corresponding to the determined road surface state by the controller; and controlling the damping force of the suspension by the controller based on the predicted vehicle behavior.

[0029] In an exemplary embodiment of the present invention, determining the road surface condition may include: setting a point where the road surface height value exceeds a first reference height value and the differential value of the road surface height value exceeds a first reference differential value as a judgment start time point; setting a point where the road surface height value exceeds a second reference height value and the differential value of the road surface height value exceeds a first reference differential value as a judgment confirmation time point; determining the road surface as an uphill road when the distance between the judgment start time point and the judgment confirmation time point is within a reference distance; and determining the road surface as an undulating road when the distance between the judgment start time point and the judgment confirmation time point exceeds a reference distance.

[0030] In an exemplary embodiment of the present invention, controlling the damping force of the suspension may include: predicting vehicle behavior corresponding to an uphill road, and controlling the damping force of the suspension based on the predicted vehicle behavior just before entering the uphill road.

[0031] In an exemplary embodiment of the present invention, determining the road surface condition may include: setting a point where the road surface height value is less than or equal to a third reference height value and the differential value of the road surface height value is less than or equal to a second reference differential value as a judgment start time point; setting a point where the road surface height value is less than or equal to a fourth reference height value and the differential value of the road surface height value is less than or equal to a second reference differential value as a judgment confirmation time point; when the distance between the judgment start time point and the judgment confirmation time point is within the reference distance, the road surface is determined to be a downhill road; when the distance between the judgment start time point and the judgment confirmation time point exceeds the reference distance, the road surface is determined to be an undulating road.

[0032] In an exemplary embodiment of the present invention, controlling the damping force of the suspension may include: predicting vehicle behavior corresponding to a downhill road, and controlling the damping force of the suspension based on the predicted vehicle behavior just before entering the downhill road.

[0033] In one embodiment of the invention, controlling the damping force of the suspension may include: predicting vehicle behavior corresponding to an undulating road, starting to control the damping force of the suspension based on the predicted vehicle behavior just before entering the undulating road, and controlling the damping force of the suspension while the vehicle is traveling on the undulating road until the vehicle's bounce and pitch are reduced to a reference value or below.

[0034] Further applications will become apparent from the description provided herein. It should be understood that this specification and specific examples are for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0035] To better understand the invention, various embodiments of the invention, given by way of example, will be described with reference to the accompanying drawings, in which:

[0036] Figure 1 This is a schematic diagram illustrating the configuration of a vehicle suspension control device according to an exemplary embodiment of the present invention;

[0037] Figure 2 This is an exemplary schematic diagram illustrating a road surface image captured by a camera included in a vehicle suspension control device according to an embodiment of the present invention;

[0038] Figure 3A This is an exemplary schematic diagram illustrating the resolution of an uphill road image captured by a camera included in a vehicle suspension control device according to an exemplary embodiment of the present invention during high-speed driving;

[0039] Figure 3B This is an exemplary schematic diagram illustrating the resolution of a downhill road captured by a camera included in a vehicle suspension control device according to another exemplary embodiment of the present invention during high-speed driving;

[0040] Figure 3C This is an exemplary schematic diagram showing the resolution of an undulating road image captured by a camera included in a vehicle suspension control device according to an embodiment of the present invention during high-speed driving.

[0041] Figure 4 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device determines that the road surface is an uphill road, according to an exemplary embodiment of the present invention.

[0042] Figure 5 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device determines that the road surface is a downhill road, according to an exemplary embodiment of the present invention.

[0043] Figure 6 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device determines that the road surface is an undulating road according to an exemplary embodiment of the present invention;

[0044] Figure 7 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device controls the suspension when the road surface is an uphill road, according to an exemplary embodiment of the present invention.

[0045] Figure 8 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device controls the suspension when the road surface is a downhill road, according to an exemplary embodiment of the present invention.

[0046] Figure 9 This is an exemplary schematic diagram illustrating, according to another embodiment of the present invention, the process by which a controller included in a vehicle suspension control device controls the suspension when the road surface is undulating;

[0047] Figure 10 This is a performance analysis diagram of a vehicle suspension control device according to an exemplary embodiment of the present invention;

[0048] Figure 11 This is a flowchart illustrating a vehicle suspension control method according to an exemplary embodiment of the present invention;

[0049] Figure 12 This is a block diagram illustrating a computational system for performing a vehicle suspension control method according to an exemplary embodiment of the present invention.

[0050] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Detailed Implementation

[0051] Some embodiments of the invention will now be described in detail with reference to the exemplary accompanying drawings. When adding reference numerals to components in each drawing, it should be noted that the same reference numerals designate components even when the same or equivalent components are shown in other drawings. Furthermore, in describing embodiments of the invention, detailed descriptions of well-known features or functions will be omitted to avoid unnecessarily obscuring the spirit of the invention.

[0052] The following description is merely exemplary in nature and is not intended to limit the invention, application, or use. It should be understood that in all the drawings, corresponding reference numerals refer to the same or corresponding parts and features.

[0053] In describing components according to exemplary embodiments of the present invention, terms such as first, second, "A", "B", (a), (b), etc., may be used. These terms are used only to distinguish one component from another, and they do not limit the nature, order, or sequence of the components. Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be understood to have meanings equivalent to those in the context of the relevant technical field, and should not be understood to have ideal or overly formal meanings, unless expressly defined as such in this application.

[0054] Figure 1 This is a schematic diagram illustrating the configuration of a vehicle suspension control device according to an exemplary embodiment of the present invention.

[0055] like Figure 1 As shown, a vehicle suspension control device 100 according to one embodiment of the present invention may include a storage device 10, a sensor 20, and a controller 30. Depending on how the vehicle suspension control device 100 is implemented, the components may be combined to form a single entity, or some components may be omitted.

[0056] Storage device 10 can store various logics, algorithms, and programs required for the following processes: when the vehicle is traveling at high speed (reference speed, for example, 110 kph), predicting the height of the road surface ahead of the vehicle based on information about the road surface obtained by sensor 20, determining the road surface condition (e.g., uphill, downhill, or undulating road) based on the variance and derivative of the predicted height value, predicting the vehicle behavior corresponding to the determined road surface condition, and adjusting the damping force of suspension 200 based on the predicted vehicle behavior.

[0057] The storage device 10 can store control information corresponding to the road surface conditions. The control information (i.e., damping force control information) may include damping control values, sky hook control values, and preview control values.

[0058] The storage device 10 can store reference height values ​​(e.g., 3 cm) and reference differential values ​​(e.g., 0.5 cm / sampling time) for determining the start time point of judgment, and reference height values ​​(e.g., 6 cm) and reference differential values ​​(e.g., 0.5 cm / sampling time) for determining the confirmation time point of judgment, as reference values ​​used in determining whether the road surface is uphill or undulating based on the differential value of the road surface height value.

[0059] The storage device 10 can store reference height values ​​(e.g., -3cm) and reference differential values ​​(e.g., -0.5cm / sampling time) for determining the start time point of judgment, and reference height values ​​(e.g., -6cm) and reference differential values ​​(e.g., -0.5cm / sampling time) for determining the confirmation time point of judgment, as reference values ​​used in determining whether the road surface is a downhill or undulating road based on the differential value of the road surface height value.

[0060] The storage device 10 can store information about the road surface acquired by the sensor 20 (e.g., image data of the road surface, LiDAR data of the road surface, radar data of the road surface, or ultrasonic data of the road surface).

[0061] Storage device 10 may include at least one type of storage medium selected from flash memory, hard disk memory, micro and card-type (e.g., Security Digital (SD) card or Ultimate Digital (XD) card) memory, random access memory (RAM) type, static RAM (SRAM) type, read-only memory (ROM) type, programmable ROM (PROM) type, electrically erasable PROM (EEPROM) type, magnetic RAM (MRAM) type, disk type and optical disk type memory.

[0062] Sensor 20 can be implemented using, for example, a camera, a lidar sensor, a radar sensor, or an ultrasonic sensor, and can acquire information about the road surface in front of the vehicle. Hereinafter, a camera will be described as an example of sensor 20. The camera can be mounted on the windshield of the vehicle and can capture images of the road surface in front of the vehicle. The camera can identify the height, depth, and length of the road surface from the image of the road surface in front of the vehicle. The number of points in the road surface image that the camera identifies for height can be, for example, 10. The image of the road surface (e.g., including images of undulating road surfaces) provided by the camera to controller 30 is as follows: Figure 2 As shown.

[0063] Figure 2 This is an exemplary schematic diagram illustrating a road surface image captured by a camera included in a vehicle suspension control device according to an exemplary embodiment of the present invention.

[0064] like Figure 2 As shown, the camera included in the vehicle suspension control device can capture images of the road surface in front of the vehicle and display the height and length of the road surface in the images.

[0065] For example, the image of the road surface may include the expected travel path 210 of the vehicle's left wheel and the expected travel path 220 of the vehicle's right wheel, and may further include the height 230 of the left side of the bump 400 and the height 240 of the right side of the bump 400. In the reference numerals "230" and "240", the vertical axis represents height and the horizontal axis represents length. Here, length represents the distance from the point where the vehicle's wheel enters the bump 400 to the point where the vehicle's wheel leaves the bump 400.

[0066] The camera can send images (image data) of the road surface to the controller 30, which include the expected travel path 210 of the vehicle's left wheel, the expected travel path 220 of the vehicle's right wheel, the height 230 of the left side of the bump 400, and the height 240 of the right side of the bump 400.

[0067] The camera can be electrically connected to the controller 30. The camera can also be connected to the controller 30 via a vehicle network. Alternatively, the camera can be connected to the controller 30 via a hard wire. In another scenario, the camera can be connected to the controller 30 via a printed circuit board (PCB). The camera can transmit images (image data) of the road surface in front of the vehicle to the controller 30. Here, the vehicle network may include a Controller Area Network (CAN), a Controller Area Network with Flexible Data Rate (CAN FD), a Local Interconnect Network (LIN), FlexRay, Media-Oriented System Transport (MOST), Ethernet, etc.

[0068] The controller 30 can perform overall control to enable the components to perform their functions correctly. The controller 30 can be implemented in hardware or software, or a combination thereof. The controller 30 can be implemented using a microprocessor, but is not limited to this.

[0069] Specifically, the controller 30 can perform various controls in the following processes: derive the height value of the road surface ahead of the vehicle based on information about the road surface acquired when the vehicle is traveling at high speed (e.g., 110 kph); determine the road surface condition (e.g., uphill, downhill, or undulating road) based on the variance and derivative of the derived height value; predict vehicle behavior corresponding to the determined road surface condition; and adjust the damping force of the suspension based on the predicted vehicle behavior.

[0070] For example, controller 30 can derive the road height value from image data of the road surface, from lidar data of the road surface, from radar data of the road surface, or from ultrasonic data of the road surface. The process of deriving the height value is a well-known and common technique. Therefore, a detailed description thereof will be omitted.

[0071] The controller 30 can be electrically connected to the suspension 200 and can control the operation of the suspension 200.

[0072] For reference, suspension 200 may include springs (not shown) and dampers (not shown) for each wheel. Suspension 200 is an electronically controlled suspension. The springs reciprocate while being compressed or stretched according to road conditions. The dampers are variable dampers capable of adjusting their damping force. Controller 30 can control the damping force of suspension 200.

[0073] When a vehicle passes over an obstacle, the damper can reduce the vibrations generated by the spring. In other words, the damper can suppress the reciprocating motion of the spring by applying a force in the opposite direction to the force generated by the spring. That is, the force that suppresses the spring's motion is called the damping force.

[0074] The damper includes a piston rod and a solenoid valve. The resistance generated as fluid flows through the fluid passage formed by the piston rod and the solenoid valve is called damping force. The damper generates damping force through compression and rebound strokes. The width of the fluid passage through which the fluid flows can be adjusted according to the movement of the solenoid valve, thereby adjusting the damping force. The suspension 200 can control the damping force of the damper based on damping force control commands and / or damping force control signals input from the controller 30.

[0075] The controller 30 can collect driving information, road information, traffic information, etc. from the navigation device 300. Specifically, the controller 30 can collect information about the road on which the vehicle is traveling (e.g., the position, height and length of bumps, the distance between bumps and the vehicle, information about bump type, curvature, slope, potholes, etc.) from the navigation device 300.

[0076] The controller 30 can acquire various information or data required for controlling the suspension 200 from various sensors equipped in the vehicle (e.g., radar, speed sensor, acceleration sensor, gyroscope sensor, etc.).

[0077] For reference, radar may include forward-facing radar and corner radar, and can acquire the relative position and relative speed of surrounding objects (e.g., another vehicle, pedestrian, cyclist, etc.). Radar may be mounted on the grille or bumper of a vehicle. Radar acquires data through transmitted radio waves emitted by a transmitting antenna and reflected radio waves received by a receiving antenna.

[0078] Radar data may include at least one of the following: information about the road surface ahead of the vehicle, or information about the distance and speed of another vehicle located around the vehicle. Information about the road surface ahead may include information about bumps or protrusions on the road. The radar can calculate the relative distance to an object based on the phase difference (or time difference) between the transmitted and reflected radio waves, and can calculate the relative velocity of the object based on the frequency difference between the transmitted and reflected radio waves. The radar can be connected to controller 30 via a vehicle network, hardwired connection, or printed circuit board. The forward radar can transmit forward radar data to controller 30. The aforementioned radar can be replaced by lidar (LiDAR).

[0079] The controller 30 can calculate the vehicle's pitch rate by processing data transmitted from the accelerometer and gyroscope sensors.

[0080] Typically, when a vehicle travels at high speeds, the accuracy of road height measurement decreases due to reduced resolution and increased noise. For reference, when the vehicle is traveling at low speeds (e.g., 20 kph), the resolution is high because the 10 identification points are located within 30 cm. However, when the vehicle is traveling at high speeds (e.g., 130 kph), the resolution is low because the 10 identification points are located within 2 m. In the following text, reference will be made to... Figures 3A to 3C This describes the resolution during high-speed driving, which is generally well-known.

[0081] Figure 3A This is an exemplary schematic diagram illustrating the resolution of an uphill road image captured by a camera included in a vehicle suspension control device according to an embodiment of the present invention during high-speed driving.

[0082] like Figure 3A As shown, when the vehicle is traveling at high speed (e.g., 130 kph), the points (hereinafter referred to as identification points 310) used to identify the road surface height in road surface images captured by a camera included in the vehicle suspension control device are distributed over a wide area 320 (e.g., 2 m) exceeding an effective distance (e.g., 30 cm). Because the resolution decreases when the identification points 310 are not distributed within the effective distance, it is difficult to accurately determine whether the road surface in front of the vehicle is uphill using conventional methods.

[0083] Figure 3B This is an exemplary schematic diagram illustrating the resolution of a downhill road image captured by a camera included in a vehicle suspension control device according to an exemplary embodiment of the present invention during high-speed driving.

[0084] like Figure 3B As shown, when the vehicle is traveling at high speed (e.g., 130 kph), the identification points 310 in the road surface image captured by the camera included in the vehicle suspension control device are distributed over a wide area 320 that exceeds the effective distance (e.g., 30 cm). Since the resolution decreases when the identification points 310 are not distributed within the effective distance, it is difficult to accurately determine whether the road surface in front of the vehicle is downhill using general methods.

[0085] Figure 3C This is an exemplary schematic diagram illustrating the resolution of an undulating road image captured by a camera included in a vehicle suspension control device according to another embodiment of the present invention during high-speed driving.

[0086] like Figure 3CAs shown, when the vehicle is traveling at high speed (e.g., 130 kph), the identification points 310 in the road surface image captured by the camera included in the vehicle suspension control device are distributed over a wide area 320 that exceeds the effective distance (e.g., 30 cm). Since the resolution decreases when the identification points 310 are not distributed within the effective distance, it is difficult to accurately determine whether the road surface in front of the vehicle is undulating using general methods.

[0087] In the following text, reference will be made to Figures 4 to 6 The process by which controller 30 determines road surface condition (e.g., uphill, downhill, or undulating) based on road surface height values ​​acquired during high-speed driving is described in detail. Controller 30 can perform the process of determining whether the road surface is flat or sloping, and when it is determined to be sloping, controller 30 can perform the process of determining the road surface condition. For example, when the variance of the road surface height values ​​exceeds a threshold (e.g., 0), controller 30 can determine that the road surface is sloping (e.g., uphill, downhill, or undulating), and when the variance does not exceed the threshold, controller 30 can determine that the road surface is flat.

[0088] Figure 4 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device determines that the road surface is an uphill road, according to an exemplary embodiment of the present invention.

[0089] exist Figure 4 In the diagram, the vertical axis represents the road surface height, and the horizontal axis represents the road surface length. The road surface length is the distance traveled in the direction of vehicle movement. "410" represents the road surface height distribution, and "420" represents the differential value of the road surface height distribution.

[0090] The controller 30 can monitor the height value of the road surface acquired during high-speed driving and can calculate the differential value of the height value.

[0091] Subsequently, the controller 30 can determine whether the road surface is uphill based on the road surface height value and its derivative. For example, the controller 30 can set the point where the road surface height value exceeds a reference height value (e.g., 3 cm) and the derivative value exceeds a reference derivative value (e.g., 0.5 cm / sampling time) as the judgment start time point, and the point where the road surface height value exceeds a reference height value (e.g., 6 cm) and the derivative value exceeds a reference derivative value (e.g., 0.5 cm / sampling time) as the judgment confirmation time point. When the distance between the judgment start time point and the judgment confirmation time point is within a reference distance, the road surface can be determined to be uphill. The reference distance can be increased or decreased proportionally to the vehicle speed.

[0092] Meanwhile, when the distance between the start time and the confirmation time exceeds the reference distance, the controller 30 can determine that the road surface is an undulating road.

[0093] Figure 5 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device determines that the road surface is a downhill road, according to an exemplary embodiment of the present invention.

[0094] exist Figure 5 In the diagram, the vertical axis represents the road surface height, and the horizontal axis represents the road surface length. The road surface length is the distance traveled in the direction of vehicle movement. "510" represents the road surface height distribution, and "520" represents the differential value of the road surface height distribution. Here, negative height values ​​represent depth values.

[0095] The controller 30 can monitor the height value of the road surface acquired during high-speed driving and can calculate the differential value of the height value.

[0096] Subsequently, the controller 30 can determine whether the road surface is downhill based on the road surface height value and its derivative. For example, the controller 30 can set a point where the road surface height value is less than or equal to a reference height value (e.g., -3cm) and the derivative of the road surface height value is less than or equal to a reference derivative value (e.g., -0.5cm / sampling time) as the judgment start time point, and a point where the road surface height value is less than or equal to a reference height value (e.g., -6cm) and the derivative of the road surface height value is less than or equal to a reference derivative value (e.g., -0.5cm / sampling time) as the judgment confirmation time point. When the distance between the judgment start time point and the judgment confirmation time point is within a reference distance, the road surface can be determined to be downhill. The reference distance can increase or decrease proportionally to the vehicle speed.

[0097] Meanwhile, when the distance between the start time and the confirmation time exceeds the reference distance, the controller 30 can determine that the road surface is an undulating road.

[0098] Figure 6 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device determines that the road surface is an undulating road, according to another embodiment of the present invention.

[0099] exist Figure 6 In the diagram, the vertical axis represents the road surface height, and the horizontal axis represents the road surface length. The road surface length is the distance traveled in the direction of vehicle movement. "610" represents the road surface height distribution, and "620" represents the differential value of the road surface height distribution.

[0100] like Figure 6As shown, the controller 30 sets a judgment start time point, but does not set a judgment confirmation time point within a reference distance from the judgment start time point. That is, there is no point where the road surface height value exceeds the reference height value (e.g., 6 cm) and the differential value of the road surface height value exceeds the reference differential value (e.g., 0.5 cm / sampling time). Therefore, the controller 30 can determine that the road surface is an undulating road.

[0101] In the following text, reference will be made to Figures 7 to 9 The method of controlling the damping force of the suspension 200 by the controller 30 based on the road surface conditions is described in detail.

[0102] Figure 7 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device controls the suspension when the road surface is uphill, according to an exemplary embodiment of the present invention.

[0103] like Figure 7 As shown, when a vehicle enters an uphill road, it may exhibit behaviors such as a positive bounce as the vehicle moves upward and a positive pitch as the front wheels move upward.

[0104] Therefore, the controller 30 can adjust the hook sway gain and pitch gain to control the suspension 200, so that the suspension 200 has a stiffer damping force than the damping force (basic damping force) on a flat road.

[0105] Furthermore, because it is difficult to accurately estimate the timing of the damper's compression and rebound during high-speed driving, and because the damper actuator is difficult to respond quickly due to its nature, the controller 30 can increase the stiffer damping force of the offset according to the vehicle's speed. That is, the controller 30 can control the damping force of the suspension 200 in advance. Just before the vehicle's behavior occurs (just before the vehicle enters an uphill section), the controller 30 can perform control, giving the suspension 200 a stiffer damping force (710) than the damping force on a flat road. Figure 7 In the figure, reference numeral "720" represents the hook control value (feedback control value), reference numeral "730" represents the offset control value (feedforward control value), and reference numeral "740" represents the final control value, which is the sum of the hook control value and the offset control value.

[0106] Figure 8 This is an exemplary schematic diagram illustrating the process by which a controller included in a vehicle suspension control device controls the suspension when the road surface is a downhill road, according to an exemplary embodiment of the present invention.

[0107] like Figure 8 As shown, when a vehicle enters a downhill road, it may exhibit vehicle behaviors such as negative bouncing as the vehicle moves downhill and negative pitching as the front wheels move downhill.

[0108] Therefore, the controller 30 can adjust the hook sway gain and pitch gain to control the suspension 200, so that the suspension 200 has a stiffer damping force than the damping force on a flat road.

[0109] Furthermore, because it is difficult to accurately estimate the timing of damper compression and rebound during high-speed driving, and because the damper actuator is difficult to respond quickly due to its nature, the controller 30 can increase the stiffer damping force of the offset according to the vehicle's speed. That is, the controller 30 can control the damping force of the suspension 200 in advance. Just before the vehicle's behavior occurs (just before the vehicle enters a downhill section), the controller 30 can perform control, giving the suspension 200 a stiffer damping force than that on a flat road (810). Figure 8 In the attached figure, reference numeral "820" represents the hook control value (feedback control value), "830" represents the offset control value (feedforward control value), and reference numeral "840" represents the final control value, which is the sum of the hook control value and the offset control value.

[0110] Figure 9 This is an exemplary schematic diagram illustrating, according to another embodiment of the present invention, the process by which a controller included in a vehicle suspension control device controls the suspension when the road surface is undulating.

[0111] like Figure 9 As shown, when a vehicle enters an undulating road, it may exhibit vehicle behaviors such as positive and negative bouncing as the vehicle moves up and down and positive and negative pitching as the front wheels move up and down.

[0112] Therefore, controller 30 can adjust the hook sway down gain and / or hook sway up gain as well as pitch gain to control suspension 200, so that suspension 200 has a stiffer damping force than the damping force on a flat road. Controller 30 can also control suspension 200 to have a softer damping force than the damping force on uphill and downhill roads.

[0113] Furthermore, because it is difficult to accurately estimate the timing of damper compression and rebound during high-speed driving, and because the damper actuator is difficult to respond quickly due to its nature, the controller 30 can increase the hard damping force of the offset according to the vehicle's speed. That is, the controller 30 can control the damping force of the suspension 200 in advance. Just before the vehicle's behavior occurs (just before the vehicle enters an undulating road), the controller 30 can perform control, so that the suspension 200 has a moderate hard damping force (910). Figure 9 In the figure, reference numeral "920" represents the hook control value (feedback control value), reference numeral "930" represents the offset control value (feedforward control value), and reference numeral "940" represents the final control value, which is the sum of the hook control value and the offset control value.

[0114] When the vehicle is traveling on an undulating road, the controller 30 can control the damping force of the suspension 200 until the vehicle's bounce and pitch decrease to or below reference values. That is, the controller 30 can control the damping force of the suspension 200 until the bounce speed (vertical movement) through the first low-pass filter (LPF) is lower than or equal to the first reference value, and the pitch speed through the second LPF is lower than or equal to the second reference value. When both conditions are met, the controller 30 can stop controlling the damping force of the suspension 200.

[0115] Figure 10 This is a performance analysis diagram of a vehicle suspension control device according to one embodiment of the present invention. Figure 10 The vehicle's bounce speed is shown.

[0116] exist Figure 10 In this context, the suspension control range represents the state where the bounce speed through the first low-pass filter (LPF) exceeds a first reference value, the pitch speed through the second LPF exceeds a second reference value, or the state where the bounce speed through the first low-pass filter (LPF) exceeds the first reference value and the pitch speed through the second LPF exceeds the second reference value. The suspension control stop range represents the state where the bounce speed through the first low-pass filter (LPF) is less than or equal to the first reference value and the pitch speed through the second LPF is less than or equal to the second reference value.

[0117] It can be seen that, as Figure 10 As shown, when the present invention is applied (1010), the vehicle's jumping speed (vertical movement) decreases compared to when the present invention is not applied (1020).

[0118] Figure 11 This is a flowchart illustrating a vehicle suspension control method according to another embodiment of the present invention, wherein the sensor shown is implemented as a camera.

[0119] First, the camera captures an image of the road surface in front of the vehicle as it travels at a reference speed (step 1101). That is, the sensor 20 acquires information about the road surface in front of the vehicle while it is in motion.

[0120] Next, the controller 30 determines the road surface condition based on the differential value of the road surface height obtained from the image of the road surface in front of the vehicle (step 1102). That is, the controller 30 obtains the road surface height value from the road surface information obtained from the sensor 20, and determines the road surface condition based on the differential value of the obtained height value. The controller 30 can determine that the road surface is one of uphill, downhill, or undulating.

[0121] Subsequently, the controller 30 predicts vehicle behavior corresponding to the determined road surface conditions and controls the damping force of the suspension based on the predicted vehicle behavior (in step 1103).

[0122] Figure 12 This is a block diagram illustrating a computational system for performing a vehicle suspension control method according to another embodiment of the invention.

[0123] refer to Figure 12 The vehicle suspension control method can be implemented through a computing system. The computing system 1000 may include at least one processor 1100, a memory 1300, a user interface input device 1400, a user interface output device 1500, a storage device 1600, and a network interface 1700, all interconnected via a system bus 1200.

[0124] Processor 1100 may be a central processing unit (CPU) or semiconductor device for processing instructions stored in memory 1300 and / or storage device 1600. Memory 1300 and storage device 1600 may include various types of volatile or non-volatile storage media. For example, memory 1300 may include read-only memory (ROM) 1310 and random access memory (RAM) 1320.

[0125] Therefore, the operation of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly in hardware or software modules executed by processor 1100, or in a combination thereof. The software modules can reside on a storage medium (i.e., memory 1300 and / or storage device 1600), such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disk, removable disk, or CD-ROM. An exemplary storage medium can be coupled to processor 1100, which can read information from and record information into the storage medium. Alternatively, the storage medium can be integrated with processor 1100. Processor 1100 and the storage medium can reside in an application-specific integrated circuit (ASIC). The ASIC can reside within a user terminal. In another case, processor 1100 and the storage medium can reside as separate components in the user terminal.

[0126] As described above, the vehicle suspension control device and method predict the height of the road surface in front of the vehicle based on information about the road surface acquired during high-speed driving, determine the road surface condition (e.g., uphill, downhill, or undulating road) based on the variance and derivative of the predicted height value, predict the vehicle behavior corresponding to the determined road surface condition, and adjust the damping force of the suspension based on the predicted vehicle behavior, thereby improving the high-speed driving stability of the vehicle.

[0127] Although the present invention has been described above with reference to exemplary embodiments and accompanying drawings, the invention is not limited thereto. Various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention as claimed in the appended claims.

[0128] Therefore, exemplary embodiments of the present invention have been provided to illustrate the spirit and scope of the invention, but are not limited thereto; thus, the spirit and scope of the invention are not limited by the embodiments. The scope of the invention should be interpreted based on the appended claims, and all technical concepts within the scope of the claims should be included within the scope of the invention.

Claims

1. A device for controlling the suspension of a vehicle, the device comprising: Sensors configured to acquire information about the road surface ahead of the vehicle while the vehicle is in motion; as well as The controller is configured as follows: The height of the road surface is determined from information about the road surface. The road surface condition is determined based on the differential value of the obtained height. Predicting vehicle behavior corresponding to the determined road conditions. The suspension damping force is controlled based on predicted vehicle behavior. The road surface condition includes at least one of uphill, downhill, or undulating road. The controller is further configured as follows: The point where the obtained road surface height value exceeds the first reference height value and the differential value of the obtained road surface height value exceeds the first reference differential value is set as the judgment start point. The point where the obtained road surface height value exceeds the second reference height value and the differential value of the obtained road surface height value exceeds the first reference differential value is set as the judgment and confirmation time point. When the distance between the start time and the confirmation time is within the reference distance, the road surface is determined to be an uphill road.

2. The device for controlling a suspension of a vehicle according to claim 1, wherein, The controller is configured to determine that the road surface is an undulating road when the distance between the start time and the confirmation time exceeds a reference distance.

3. The apparatus for controlling a suspension of a vehicle according to claim 1, wherein, The controller is configured to predict vehicle behavior corresponding to an uphill road and control the damping force of the suspension based on the predicted vehicle behavior just before entering the uphill road.

4. The device for controlling a suspension of a vehicle according to claim 3, wherein, The controller is configured to control the suspension such that the suspension has a damping force that is stiffer than the basic damping force.

5. The apparatus for controlling a suspension of a vehicle according to claim 1, wherein, The controller is configured as follows: The point where the obtained road surface height value is less than or equal to the third reference height value and the differential value of the obtained road surface height value is less than or equal to the second reference differential value is set as the judgment start time point. The point where the obtained road surface height value is less than or equal to the fourth reference height value and the differential value of the obtained road surface height value is less than or equal to the second reference differential value is set as the judgment and confirmation time point. When the distance between the start time and the confirmation time is within the reference distance, the road surface is determined to be a downhill road.

6. The device for controlling a suspension of a vehicle according to claim 5, wherein, The controller is configured to determine that the road surface is an undulating road when the distance between the start time and the confirmation time exceeds a reference distance.

7. The apparatus for controlling a suspension of a vehicle according to claim 5, wherein, The controller is configured to predict vehicle behavior corresponding to a downhill road and control the damping force of the suspension based on the predicted vehicle behavior just before entering the downhill road.

8. The device for controlling a suspension of a vehicle according to claim 7, wherein, The controller is configured to control the suspension such that the suspension has a damping force that is stiffer than the basic damping force.

9. The apparatus for controlling a suspension of a vehicle according to claim 2 or 6, wherein, The controller is configured to predict vehicle behavior corresponding to undulating roads and control the damping force of the suspension based on the predicted vehicle behavior just before entering the undulating road.

10. The device for controlling a suspension of a vehicle according to claim 9, wherein, When the vehicle is traveling on an undulating road, the controller is configured to control the damping force of the suspension until the vehicle’s bounce and pitch are equal to or less than reference values.

11. The apparatus for controlling a suspension of a vehicle according to claim 1, wherein, When the variance of the road surface height exceeds a threshold, the controller is configured to perform a process to determine the road surface condition.

12. A method for controlling the suspension of a vehicle, the method comprising: During vehicle operation, sensors acquire information about the road surface ahead of the vehicle. The controller derives the road surface height value from the information acquired about the road surface. The controller determines the road surface condition based on the differential value of the derived height value; Vehicle behavior predicted and determined by the controller corresponding to the road surface conditions; The controller adjusts the suspension damping force based on predicted vehicle behavior. The road surface condition includes at least one of uphill, downhill, or undulating road. Determining the road surface condition includes: The point where the obtained road surface height value exceeds the first reference height value and the differential value of the obtained road surface height value exceeds the first reference differential value is set as the judgment start time point; The point where the obtained road surface height value exceeds the second reference height value and the differential value of the obtained road surface height value exceeds the first reference differential value is set as the judgment and confirmation time point; In response to the determination that the distance between the judgment start time point and the judgment confirmation time point is within the reference distance, the road surface is determined to be an uphill road.

13. The method of claim 12, wherein, Determining the road surface condition further includes: In response to the determination that the distance between the judgment start time point and the judgment confirmation time point exceeds the reference distance, the road surface is determined to be an undulating road.

14. The method of claim 13, wherein, The damping forces controlling the suspension include: Predict vehicle behavior corresponding to uphill roads; Just before entering an uphill section, the suspension damping force is controlled based on predicted vehicle behavior.

15. The method of claim 12, wherein, Determining the road surface condition includes: The point where the obtained road surface height value is less than or equal to the third reference height value and the differential value of the obtained road surface height value is less than or equal to the second reference differential value is set as the judgment start time point; The point where the obtained road surface height value is less than or equal to the fourth reference height value and the differential value of the obtained road surface height value is less than or equal to the second reference differential value is set as the judgment and confirmation time point. In response to the determination that the distance between the judgment start time point and the judgment confirmation time point is within the reference distance, the road surface is determined to be a downhill road; In response to the determination that the distance between the judgment start time point and the judgment confirmation time point exceeds the reference distance, the road surface is determined to be an undulating road.

16. The method according to claim 15, wherein, The damping forces controlling the suspension include: Predict vehicle behavior corresponding to downhill roads; Just before entering a downhill section, the suspension damping force is controlled based on predicted vehicle behavior.

17. The method of claim 13 or 15, wherein, The damping forces controlling the suspension include: Predict vehicle behavior corresponding to undulating roads; Just before entering the undulating road, the damping force of the suspension begins to be controlled based on the predicted vehicle behavior; When the vehicle is traveling on an undulating road, control the damping force of the suspension until the vehicle's bounce and pitch are equal to or less than the reference value.

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