System and method for controlling braking of a vehicle

Abstract

Disclosed are a system and method of controlling braking of a vehicle by adjusting an amount of braking of an inner wheel during a turn of the vehicle to prevent a slip and secure a driving force of an outer wheel. The method includes the steps of receiving, by an electronic stability control (ESC) device, a function activation request; determining, by the ESC device in response to the function activation request, whether an execution condition for braking control of the inner wheel for the turn of the vehicle is satisfied, and when the execution condition is satisfied, controlling a brake pressure by determining and adjusting a brake pressure control amount of the inner wheel during the turn of the vehicle based on a pre-set coefficient.

Description

Technical Field

[0001] This invention relates to systems and methods for controlling the braking of a vehicle, and more specifically, to a system and method for controlling braking to prevent slippage and ensure driving force of the outer wheels by adjusting the amount of braking of the inner wheels when the vehicle is turning. Background Technology

[0002] A differential is a necessary component of a vehicle that enables it to turn. A differential allows a vehicle to turn by compensating for the difference in revolutions per minute (RPM) between the inner and outer wheels.

[0003] When a vehicle turns, the inner wheel of the drive wheels slips due to the movement of the load. Specifically, when there is a large speed difference between the inner and outer wheels, the differential may not be able to transmit sufficient driving force from the slipping inner wheel to the outer wheel of the drive wheels opposite to the inner wheel.

[0004] To compensate for the limitations of differentials, mechanical devices such as limited-slip differentials (LSDs) are typically used. While devices such as LSDs advantageously prevent slippage, the overall cost and weight of the vehicle may increase, and layout changes are required when using mechanical devices that include clutches. Furthermore, the research and development of implementing such mechanical devices on different vehicles can incur development costs. Summary of the Invention

[0005] In one aspect, the present invention provides a system and method for controlling braking to overcome the problem that driving force is not transmitted to the outer wheel when the inner wheel slips during vehicle cornering, without using mechanical devices such as a limited-slip differential (LSD).

[0006] The technical problems solved by the implementation scheme are not limited to those described above, and other technical problems not described herein will become apparent to those skilled in the art from the following description.

[0007] To achieve the objectives of the present invention as described above, and to perform the characteristic functions according to the present invention, the present invention has the following features.

[0008] In one aspect, the present invention provides a method for controlling braking, the method comprising receiving a function activation request, responding to the function activation request by determining whether execution conditions for braking control of the inner wheel of a vehicle during turning are met, and when the execution conditions are met, controlling braking pressure by determining and adjusting the braking pressure control amount of the inner wheel during turning of the vehicle based on a preset coefficient. Attached Figure Description

[0009] The above and other features of the invention will now be described in detail with reference to specific exemplary embodiments illustrated in the accompanying drawings. The drawings provided below are for illustrative purposes only and are therefore not restrictive of the invention, wherein:

[0010] Figure 1 This is a schematic diagram showing the configuration of the braking control system according to the present invention;

[0011] Figure 2 This is a flowchart showing the operation of the execution condition determiner of the braking control system according to the present invention;

[0012] Figure 3 This is a schematic diagram showing the execution conditions of the braking control system according to the present invention;

[0013] Figure 4 This is a flowchart showing the operation of the steering inner and outer wheel determiner of the braking control system according to the present invention;

[0014] Figure 5 This is a schematic diagram illustrating an example of the characteristics of a vehicle's tires;

[0015] Figure 6 This is a flowchart of the braking control method according to the present invention;

[0016] Figure 7 This is a flowchart of a braking control method according to some embodiments of the present invention. Detailed Implementation

[0017] It should be understood that the term "vehicle" or "of a vehicle" or other similar terms as used herein generally includes motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, boats including various vessels, aircraft, etc., and includes hybrid vehicles, electric vehicles, hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., vehicles derived from non-petroleum fuels). As mentioned herein, a hybrid vehicle is a vehicle with two or more power sources, such as both gasoline and electric power.

[0018] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the stated feature, value, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, values, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Throughout the specification, unless expressly stated to the contrary, the term “comprising” and variations such as “including” or “including” should be understood to imply the inclusion of the stated element but not exclude any other element. Furthermore, the terms “unit,” “device,” “component,” and “module” described in the specification mean a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0019] Furthermore, the control logic of the present invention can be implemented as a non-transient computer-readable medium on a computer-readable medium, which contains executable program instructions that are executed by a processor, controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage devices. The computer-readable medium can also be distributed across a network-connected computer system, such that the computer-readable medium is stored and executed in a distributed manner, for example, via a telematics server or a controller area network (CAN).

[0020] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The specific structures or functions described in the embodiments of the present invention are for illustrative purposes only. Embodiments of the concept of the present invention can be implemented in various forms, and it should be understood that they should not be construed as limited to the embodiments described herein, but rather include all modifications, equivalents, or substitutions included within the spirit and scope of the invention.

[0021] It should be understood that although the terms "first," "second," etc., are used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, the first element discussed below may be referred to as the second element without departing from the teachings of the invention. Similarly, the second element may also be referred to as the first element.

[0022] It should be understood that when an element is referred to as "connected" or "attached" to another element, it can be directly connected to or attached to the other element, or there can be an intermediate element between them. Conversely, it should be understood that when an element is referred to as "directly connected" or "directly attached" to another element, there is no intermediate element. Other expressions explaining the relationship between elements, such as "between," "directly between," "adjacent," or "directly adjacent," should also be interpreted in the same way.

[0023] Throughout this specification, the same reference numerals denote the same elements. Meanwhile, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0024] This invention addresses the problem of driving force not being transmitted to the outer wheels when the inner wheel slips during vehicle cornering by adjusting braking pressure without using mechanical devices such as a limited-slip differential (LSD).

[0025] Specifically, according to the present invention, braking pressure can be regulated using an electronic stability control (ESC) system included in the vehicle without implementing a new, separate system. Specifically, according to the present invention, by utilizing the ESC system to determine slippage of the inner wheel and preventing slippage through hydraulic braking pressure, driving force can be transmitted to the outer wheel.

[0026] Therefore, the present invention can provide drivers with a dynamic driving environment by improving performance for cornering and drifting functions (e.g., on a racetrack).

[0027] Compared to vehicles using conventional mechanical equipment, the cost and weight of vehicles according to the present invention can be significantly reduced, and layout design for installing such mechanical equipment can be eliminated.

[0028] In addition, it can reduce the development costs and manpower required to apply traditional mechanical equipment to different vehicle models.

[0029] The various specific embodiments of the present invention will now be described in detail, examples of which are shown and described in the accompanying drawings.

[0030] like Figure 1 As shown, the braking control system according to the present invention may include an Electronic Stability Control (ESC) unit (or device) 100 and a controller 200 for braking control according to the present invention. The controller 200 may be integrated into the ESC unit 100, or it may be a separate controller configured to communicate with the ESC unit 100. Hereinafter, the present invention will be described with reference to the controller 200 integrated into the ESC unit 100.

[0031] The ESC unit 100 can be configured to receive measurement information from various sensors of the vehicle in real time. Specifically, the ESC unit 100 can receive information about the vehicle's steering angle from the steering angle sensor 10, information about lateral acceleration from the lateral acceleration sensor 20, and information about yaw rate from the yaw rate sensor 30. The ESC unit 100 can acquire information about the wheel speed from the vehicle's wheel speed sensor 40. The ESC unit 100 can obtain information about the drive torque from the torque sensor 50 and information about changes in accelerator pedal travel from the accelerator pedal travel sensor 60.

[0032] ESC unit 100 can receive input from function request unit 70. According to an embodiment of the invention, function request unit 70 can be a function activation button installed in the passenger compartment and can receive on / off input from the driver. Specifically, when the driver wishes to drive or drift on the runway, they can perform braking control according to the invention by manipulating function request unit 70. When function request unit 70 receives an on input, ESC unit 100 can standby to perform braking control according to the invention and can be configured to control braking according to the invention when the execution conditions described below are met. That is, as... Figure 2 As shown, after the function is activated, it can be determined whether the execution conditions are met in the standby state (S40). When the execution conditions for performing braking control are met, braking control can be performed (S42, enter control). When the execution conditions are not met, the braking control system can remain in standby (S30, standby to enter control).

[0033] ESC unit 100 may include execution condition determiner 210. Execution condition determiner 210 can determine whether actual control of hydraulic braking pressure is needed to prevent wheel slippage when in standby mode for brake control. Figure 3 As shown, the execution condition determiner 210 can determine the turning condition C1, the acceleration condition C2, and the slip condition C3. When these conditions C1, C2, and C3 are satisfied, the operation for brake pressure control according to the present invention can be performed.

[0034] The execution condition determiner 210 can determine whether turning condition C1 is met based on the vehicle's current steering angle, lateral acceleration, and yaw rate. The steering angle can be input to the execution condition determiner 210 from the steering angle sensor 10, the lateral acceleration from the lateral acceleration sensor 20, and the yaw rate from the yaw rate sensor 30. When the steering angle is greater than a preset reference steering angle F1, the lateral acceleration is greater than a preset reference lateral acceleration F2, and the yaw rate is greater than a preset reference yaw rate F3—that is, when all three conditions are met—the execution condition determiner 210 can determine that turning condition C1 is met.

[0035] The execution condition determiner 210 can determine whether the acceleration condition C2 is met based on information about the vehicle's front wheel speed, drive torque, and gear position. That is, when the front wheel speed is greater than a preset reference front wheel speed F4, the drive torque is greater than a preset reference drive torque F5, and the gear position is a preset reference gear F6, that is, when all three conditions are met, the execution condition determiner 210 can determine that the acceleration condition C2 is met.

[0036] The execution condition determiner 210 can be configured to determine whether slip condition C3 is satisfied. When the slip difference between the inner and outer wheels of the drive wheel is greater than the preset reference slip difference F7, the execution condition determiner 210 can determine that slip condition C3 is satisfied.

[0037] In this scenario, it can be first determined which wheel is the inner wheel and which wheel is the outer wheel when the vehicle is turning. The ESC unit 100 may include an inner / outer wheel determiner 220. The inner / outer wheel determiner 220 can determine whether the inner wheel is the left or right wheel when the vehicle is turning. Figure 4 As shown, according to an embodiment of the present invention, the inner and outer wheel determiner 220 can acquire information about the current yaw rate from the yaw rate sensor 30 and can determine whether the yaw rate is negative or positive (S222). When the acquired yaw rate is greater than 0, the inner and outer wheel determiner 220 can determine that the inner wheel is the left rear wheel RL and the outer wheel is the right rear wheel RR (S224). Conversely, when the yaw rate has a negative value less than 0, the inner and outer wheel determiner 220 can determine that the inner wheel is the right rear wheel RR and the outer wheel is the left rear wheel RL (S226). Here, the left side represents the driver's side, and the right side represents the passenger's side. Depending on the settings, the reverse is also possible.

[0038] When the execution conditions, including turning condition C1, acceleration condition C2, and slip condition C3, are met, the ESC unit 100 can perform a series of operations for brake pressure control. That is, the ESC unit 100 can determine the brake pressure control amount and control the brake pressure based on the determined brake pressure control amount. Therefore, according to an embodiment of the present invention, the ESC unit 100 may include a target slip calculation unit 230 for the inner wheel, a target wheel speed calculation unit 240 for the inner wheel, a slip error calculation unit 250, a target braking torque calculation unit 260, and a target braking amount calculation unit 270.

[0039] The inner wheel target slip calculation unit 230 can be configured to calculate the target slip of the inner wheel during turning. One objective of the braking control according to the invention is to limit the slip of the inner wheel during turning based on the characteristics of the vehicle, thereby ensuring maximum driving force. Since the maximum driving force can vary depending on the characteristics of the vehicle's tires (corresponding to tire friction due to slip), the slip used to ensure maximum driving force can be determined based on tire characteristic values. When test values ​​of tire characteristics are input as parameters, the inner wheel target slip calculation unit 230 can determine the maximum slip ratio corresponding to the current driving speed and can determine the target slip λ. target For example, when the characteristics of a vehicle's tires are as follows... Figure 5 As shown, the appropriate target slip to ensure maximum driving force can be given, as shown in Table 1 below.

[0040] [Table 1]

[0041]

[0042]

[0043] As described above, the target slip λ of the inner wheel can be calculated based on the target slip calculation unit 230 of the inner wheel. target To calculate the target wheel speed V of the inner wheel iw,target Based on the formula for calculating wheel slip, the target slip λ of the inner wheel can be obtained as shown in Equation 1. target The equation.

[0044] [Equation 1]

[0045]

[0046] The inner wheel target wheel speed calculation unit 240 can calculate the inner wheel target wheel speed V using Equation 2 (relative to the inner wheel target wheel speed V). iw,target Transform equation 1) to calculate the target wheel speed V of the inner wheel. iw,target .

[0047] [Equation 2]

[0048]

[0049] Here, V is the current vehicle speed, which can be expressed in kilometers per hour.

[0050] ESC unit 100 may include slip error calculation unit 250. As shown in Equation 3 below, slip error calculation unit 250 can calculate the current slip λ of the inner wheel and the target slip λ calculated according to Equation 1. target The slip error e between the inner and outer wheels. The slip error e can be compared with the calculated target wheel speed V of the inner wheel. iw,target Together they affect the amount of brake pressure control.

[0051] [Equation 3]

[0052] e = λ - λ target

[0053] The slip λ of the inner wheel can be calculated according to Equation 4 below.

[0054] [Equation 4]

[0055]

[0056] Here, V iw It can be the current rotational speed of the inner wheel.

[0057] ESC unit 100 can be based on the target inner wheel speed V iw,target and target braking torque τ target To determine the braking pressure control amount, that is, it can be based on the determined target wheel speed V of the inner wheel. iw,target Determine the target braking torque τ target It can be based on the determined target braking torque τ. target Determine the target braking amount P target Therefore, the ESC unit 100 may include a target braking torque calculation unit 260 and a target braking amount calculation unit 270.

[0058] The target braking torque calculation unit 260 can determine the target braking torque τ according to the following equation 5. target Target braking torque τ target It can be a computational region used to determine the braking torque required to meet the target speed, and can be calculated based on the correlation between energy and speed.

[0059] [Equation 5]

[0060]

[0061] Here, W is the vehicle weight specification value, and rev is the engine speed per minute (RPM).

[0062] When the target braking torque τ is calculated target At that time, the target braking amount calculation unit 270 can calculate the target braking amount P according to the following equation 6. target Target braking amount P target It can be used to determine whether the target braking torque τ is met. target The hydraulic braking amount, and the target braking amount P target It can be determined based on wheel dynamics, which corresponds to the correlation between wheel torque and braking pressure.

[0063] [Equation 6]

[0064]

[0065] Here, r is the radius of the tire, μ is the coefficient of friction of the friction material, and r' is the effective braking radius.

[0066] ESC unit 100 can determine the target braking amount P target Apply to the slipping inner wheel to prevent it from slipping.

[0067] The following will refer to Figure 6 and Figure 7 The braking control method according to the present invention is described.

[0068] In step S10, the braking control method according to the present invention can be started.

[0069] In step S20, a function activation request can be entered. This request can be executed by manipulating an activation button for the braking control function according to the invention, installed in the vehicle compartment. As a non-limiting example, the activation button's input can be a button for allowing the vehicle to enter a runway driving mode. As another non-limiting example, the activation button's input can be a button for allowing the vehicle to enter a drift mode.

[0070] When a function activation request is input, the vehicle can enter a standby state for braking control according to the invention (S30). Here, it can be determined whether the execution conditions for performing braking control according to the invention are met during the standby state (S40). Even if a function activation request is input, it can be determined whether hydraulic control is actually needed to prevent wheel slippage. Braking control according to the invention can only be performed when the execution conditions are met.

[0071] As described above, the execution conditions may include turning condition C1, acceleration condition C2, and slip condition C3. When each condition is met, a series of operations for brake pressure control can be performed (S60).

[0072] In step S62, the target slip λ of the inner wheel can be determined based on the tire characteristic values. target It can be based on the determined target slip λ of the inner wheel. target Calculate the target wheel speed V of the inner wheel according to Equation 2. iw,target (S64).

[0073] When the target wheel speed V of the inner wheel is determined iw,target At that time, the target braking torque τ can be calculated according to Equation 5. target The target braking amount P can be calculated based on Equation 6. target (S66).

[0074] ESC unit 100 can, based on the calculated target braking amount P target The hydraulic braking amount of the inner wheel is adjusted to perform braking control according to the invention (S70).

[0075] In step S80, the conditions for terminating brake pressure control can be determined. Brake pressure control can be terminated when the function activation request is released (S90). As described above, brake pressure control can be terminated when there is a driver input to close the activation button.

[0076] When at least one of the turning condition C1, acceleration condition C2, or slip condition C3 is not met, the brake pressure control can enter a standby state for control (S44). For example, when the steering angle is less than or equal to a preset reference steering angle, the vehicle can enter a standby state for control regardless of whether other conditions are met, and brake pressure control can be executed when all execution conditions are met again.

[0077] This invention can utilize braking control to control inner wheel slip that occurs during vehicle cornering without the need for mechanical devices (e.g., LSD), thereby providing a dynamic driving environment that improves cornering performance and facilitates drifting (e.g., on a track), and can reduce vehicle cost and weight, development costs and manpower compared to existing technologies.

[0078] This invention provides a method for preventing inner wheel slippage during cornering and utilizing the vehicle's maximum driving force through braking control.

[0079] This invention can provide a pressure control method and system through conventionally used electronic stability control (ESC) systems, without the need for a separate system.

[0080] The present invention can provide a braking control system and method for making driving a vehicle more enjoyable by improving cornering performance and enhancing drifting capabilities during track driving.

[0081] Those skilled in the art will understand that the effects achievable by the present invention are not limited to those specifically described above, and other advantages of the present invention will become clearer from the above detailed description.

[0082] The invention has been described in detail with reference to preferred embodiments. However, those skilled in the art will understand that changes can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A method for controlling braking, the method comprising: The electronic stability control device receives the function activation request; In response to a function activation request, the electronic stability control device determines whether the execution conditions for braking control of the inner wheel for cornering of the vehicle are met. When the execution conditions are met, the braking pressure is controlled by determining and adjusting the braking pressure control amount of the inner wheel during vehicle turning based on a pre-set coefficient. The execution conditions include acceleration conditions configured to determine whether the vehicle accelerates, and acceleration conditions are determined to be met when the vehicle's front wheel speed is greater than a preset reference front wheel speed, the vehicle's drive torque is greater than a preset reference drive torque, and the vehicle's gear is a preset reference gear.

2. The method according to claim 1, wherein, When the turning condition configured to determine whether the vehicle is turning, the acceleration condition, and the slip condition configured to determine the wheel speed difference between the inner and outer wheels are all satisfied, it is determined that the execution condition is satisfied.

3. The method according to claim 2, wherein, When the vehicle's steering angle is greater than the preset reference steering angle, the vehicle's lateral acceleration is greater than the preset reference lateral acceleration, and the vehicle's yaw rate is greater than the preset reference yaw rate, the turning conditions are determined to be met.

4. The method according to claim 2, wherein, The slip condition is met when the slip difference between the inner and outer wheels during a turn is greater than the preset reference slip difference.

5. The method according to claim 4, wherein, The inner wheel is determined during turning based on the vehicle's yaw rate.

6. The method according to claim 1, wherein, Controlling braking pressure includes calculating the target braking amount based on the target slip of the inner wheel and the target wheel speed during vehicle cornering.

7. The method according to claim 6, wherein, Controlling braking pressure includes: Target slip is determined based on the characteristics of the vehicle's tires.

8. The method of claim 7, further comprising: The target wheel speed of the inner wheel is calculated based on the target slip.

9. The method of claim 8, further comprising: The target braking torque of the vehicle is calculated based on the calculated target wheel speed and the current wheel speed.

10. The method of claim 9, further comprising: The target braking amount is determined based on the target braking torque.

11. The method according to claim 10, wherein, The hydraulic braking amount of the inner wheel is adjusted based on the target braking amount, and the hydraulic braking amount is adjusted by the vehicle's electronic stability control equipment.

12. The method according to claim 1, wherein, When the function activation request is cancelled, control of the braking pressure is terminated.

13. The method according to claim 2, wherein: In the control of braking pressure, the control of braking pressure is terminated when at least one of the turning conditions, acceleration conditions, or slip conditions is not met. When the turning conditions, acceleration conditions, and slip conditions are all met again, brake pressure control is implemented.

14. The method of claim 7, further comprising: Calculate the slip error between the target slip and the current slip of the inner wheel, where the slip error is reflected in the target braking amount.

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