Brake control system and control method

Abstract

To provide a brake control system and a control method which adjust a brake amount of an inner wheel in vehicle turning and prevent slip, and can secure a driving force of an outer wheel.SOLUTION: A brake control method includes: a step of receiving a function activation request; a step of determining whether an execution condition for brake control of a turning inner wheel of a vehicle is satisfied in response to the function activation request; and a brake pressure control step of determining and adjusting a brake pressure control amount of the inner wheel in vehicle turning on the basis of a previously set factor when the execution condition is satisfied.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a brake control system and a control method, and more particularly to a brake control system and a control method that adjust the amount of braking of an inside wheel when a vehicle is cornering, thereby preventing slippage and ensuring driving force of an outside wheel. [Background technology]

[0002] A differential gear is an essential device for turning a vehicle, and enables the vehicle to turn by compensating for the difference in rotation speed between the inner and outer wheels.

[0003] When a vehicle turns, the shift in load causes slippage in the inside drive wheel. In particular, when there is a large speed difference between the inside and outside wheels, the differential gear prevents sufficient driving force from being transmitted to the outside drive wheel, which is the wheel opposite the slipping inside drive wheel.

[0004] To compensate for the limitations of differential gears, mechanical devices such as limited slip differentials (LSDs) are generally used. Devices like LSDs are effective in suppressing slippage, but they have the disadvantages of increasing costs and weight because they use mechanical devices such as clutches, and requiring vehicle layout. In addition, the development costs and labor required to reflect the characteristics of each vehicle are not negligible. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Korean Patent Registration No. 10-0930946 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a brake control system and control method that can solve the problem of driving force not being transmitted to the outside wheel when inside wheel slip occurs during cornering of a vehicle without applying a mechanical device such as a limited slip differential. [Means for solving the problem]

[0007] In order to achieve the above object, according to one aspect of the present invention, a brake control method includes: receiving a function activation request; determining whether an execution condition for brake control of an inside wheel of a vehicle when the vehicle is turning is satisfied in response to the function activation request; and, if the execution condition is satisfied, determining and adjusting a brake pressure control amount of the inside wheel when the vehicle is turning based on a preset factor. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a method for suppressing slip of the inside wheel of a turn using brake control, thereby making maximum use of the vehicle driving force. Furthermore, according to the present invention, a separate system is not required, and a pressure control method and system can be implemented using an existing Electronic Stability Control (ESC). Furthermore, it is possible to provide a brake control system and a control method that can assist cornering exit performance and drifting function when driving on a circuit, and can provide the driver with the enjoyment of driving a vehicle. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a configuration diagram of a brake control system according to an embodiment of the present invention. [Figure 2] 5 is a flowchart showing the operation of an execution condition determination unit in the brake control system according to the embodiment of the present invention. [Figure 3]FIG. 3 is a diagram showing execution conditions of the brake control system according to one embodiment of the present invention. [Figure 4] 5 is a flowchart showing the operation of a turning inside / outside wheel determination unit of the brake control system according to one embodiment of the present invention. [Figure 5] FIG. 1 illustrates tire characteristics for an exemplary arbitrary vehicle. [Figure 6] 3 is a flowchart illustrating a brake control method according to one embodiment of the present invention. [Figure 7] 3 is a flowchart illustrating in detail a brake control method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The specific structure or functionality presented in the embodiments of the present invention is merely exemplary for the purpose of describing embodiments based on the concepts of the present invention, and the embodiments based on the concepts of the present invention can be embodied in various forms. Furthermore, the present invention is not limited to the embodiments described herein, but includes any modifications, equivalents, or alternatives within the spirit and technical scope of the present invention.

[0011] In this specification, terms such as "first" and / or "second" are used to describe various components, but the components are not limited to these terms. The terms are used only to distinguish one component from another. For example, within the technical scope based on the concept of the present invention, a first component may be named a second component, and similarly, a second component may be named a first component.

[0012] When a component is described as being "coupled" or "connected" to another component, it may be directly coupled or connected to the other component, but there may be other components in between. On the other hand, when a component is described as being "directly coupled" or "directly connected" to another component, there are no other components in between. Other expressions describing the relationship between components, such as "between" and "directly between," or "adjacent to" and "directly adjacent to," should be interpreted similarly.

[0013] The same reference numerals refer to the same elements throughout this specification. The terms used in this specification are for the purpose of describing embodiments only and are not intended to limit the present invention. In this specification, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. As used in this specification, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other elements, steps, operations, and / or elements.

[0014] According to the present invention, the problem of driving force not being transmitted to the outside wheel when slip occurs on the inside wheel during cornering can be solved by using brake pressure modulation instead of a mechanical device such as an LSD.

[0015] In particular, the present invention makes it possible to adjust the brake pressure by utilizing the ESC system installed in the vehicle without building a separate new system. In particular, the present invention detects slippage of the inside wheel and transmits driving force to the outside wheel by suppressing slippage with brake hydraulic pressure using the ESC system.

[0016] As a result, the present invention can improve cornering exit performance and drifting function, providing the driver with a dynamic driving environment.

[0017] Furthermore, compared to vehicles using conventional mechanical devices, the cost and weight can be significantly reduced, and there is no need to secure a layout for installing the mechanical devices.

[0018] Furthermore, it is possible to reduce the system development costs and labor required when applying conventional mechanical devices.

[0019] The present invention will be described in detail below with reference to the drawings.

[0020] 1 , a brake control system according to one embodiment of the present invention includes an ESC unit 100 and a control unit 200 for brake control according to the present invention. The control unit 200 may be a controller integrated into the ESC unit 100, or may be a separate controller configured to communicate with the ESC unit 100. In the following, the control unit 200 will be described as a controller integrated into the ESC unit 100.

[0021] The ESC unit 100 is configured to acquire measurement information in real time from various sensors of the vehicle. In particular, the ESC unit 100 receives vehicle steering angle information from a steering angle sensor 10, receives lateral acceleration information from a lateral acceleration sensor 20, and collects yaw rate information from a yaw rate sensor 30. The ESC unit 100 also collects wheel speed information from a wheel speed sensor 40 of the vehicle. The ESC unit 100 also obtains driving torque information from a torque sensor 50 and collects accelerator pedal stroke change amount information from an accelerator pedal stroke sensor 60.

[0022] The ESC unit 100 also receives input from a function request unit 70. According to one embodiment of the present invention, the function request unit 70 is a function activation button provided in the vehicle cabin that can be turned on or off by the driver. In particular, when the driver desires circuit driving or drift driving, the driver operates the function request unit 70 to perform brake control according to the present invention. When the function request unit 70 receives an on input, the ESC unit 100 enters a standby state in which brake control according to the present invention can be performed. When an execution condition, described below, is satisfied, the ESC unit 100 controls the brakes according to the control method of the present invention. That is, as shown in FIG. 2 , in the standby state after function activation, it is determined whether the execution condition is satisfied (S40). If the execution condition for performing brake control is satisfied, brake control is performed (S42, enter control), and if the execution condition is not satisfied, the ESC unit remains in the standby state (S30, wait for control entry).

[0023] The ESC unit 100 includes an execution condition determination unit 210. The execution condition determination unit 210 determines whether brake hydraulic pressure control for wheel slip suppression is actually required in a brake control execution standby state. As shown in Fig. 3, the execution condition determination unit 210 determines a turning condition C1, an acceleration condition C2, and a slip condition C3, and performs the brake pressure control step according to the present invention when these conditions C1, C2, and C3 are met.

[0024] The execution condition determination unit 210 determines whether the turning condition C1 is satisfied based on the steering angle, lateral acceleration, and yaw rate of the current vehicle. The steering angle is input to the execution condition determination unit 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. The execution condition determination unit 210 determines that the turning condition C1 is satisfied when the steering angle exceeds a preset reference steering angle F1, the lateral acceleration exceeds a preset reference lateral acceleration F2, and the yaw rate exceeds a preset reference yaw rate F3, i.e., when all three conditions are satisfied.

[0025] The execution condition determination unit 210 determines whether the acceleration condition C2 is satisfied based on information on the front wheel speed, drive torque, and drive gear of the vehicle. That is, the execution condition determination unit 210 determines that the acceleration condition C2 is satisfied when the front wheel speed exceeds a preset reference front wheel speed F4, the drive torque exceeds a preset reference drive torque F5, and the drive gear is a preset reference drive gear F6, that is, when all three conditions are satisfied.

[0026] The execution condition determination unit 210 is configured to determine whether the slip condition C3 is satisfied. If the slip difference between the inside wheel and the outside wheel of the driving wheels exceeds a preset reference slip difference F7, the execution condition determination unit 210 determines that the slip condition C3 is satisfied.

[0027] At this time, the distinction between the inside wheel and the outside wheel during a turn is prioritized. The ESC unit 100 includes an inside / outside wheel determination unit 220, which determines whether the inside wheel is the left wheel or the right wheel during a turn. As shown in FIG. 4, according to one embodiment of the present invention, the inside / outside wheel determination unit 220 collects current yaw rate information from the yaw rate sensor 30 and determines whether the yaw rate is a negative or positive value (S222). If the collected yaw rate exceeds zero, the inside / outside wheel determination unit 220 determines that the inside wheel is the left rear wheel RL and the outside wheel is the right rear wheel RR (S224). Conversely, if the yaw rate is a negative number less than zero, the inside wheel is determined to be the right rear wheel RR and the outside wheel is determined to be the left rear wheel RL (S226). Here, the left side refers to the driver's seat, and the right side refers to the passenger seat. The opposite case is also possible depending on the settings.

[0028] When the execution conditions, including the turning condition C1, the acceleration condition C2, and the slip condition C3, are satisfied, the ESC unit 100 performs a series of steps for brake pressure control. That is, the ESC unit 100 determines the brake pressure control amount and controls the brake pressure based on the determined amount. To this end, in this embodiment, the ESC unit 100 includes an inner wheel target slip calculation unit 230, an inner wheel target wheel speed calculation unit 240, a slip error calculation unit 250, a target braking torque calculation unit 260, and a target braking amount calculation unit 270.

[0029] The inside wheel target slip calculation unit 230 is configured to calculate the target slip of the inside wheel during a turn. The purpose of the brake control according to the present invention is to limit and control the inside wheel slip during a turn in accordance with the vehicle characteristics in order to ensure maximum driving force. Since the maximum driving force varies depending on the vehicle tire characteristics, which are the frictional force of the tire due to slip, the slip for ensuring maximum driving force is determined based on the tire characteristic value. When the tire characteristic test value is input as a parameter, the inside wheel target slip calculation unit 230 determines the maximum slip ratio corresponding to the current driving speed and calculates the target slip λ. target For example, when the tire characteristics of a vehicle are given as shown in FIG. 5, the appropriate target slip for ensuring maximum driving force is given as shown in Table 1.

[0030] [Table 1]

[0031] The target slip λ of the inner wheel determined by the inner wheel target slip calculation unit 230 as described above target to the target wheel speed V of the inner wheel iw,target Based on the wheel slip calculation formula, the target slip λ of the inner wheel is calculated as shown in Equation 1. target The formula for

[0032]

number

[0033] The inner wheel target wheel speed calculation unit 240 calculates the target wheel speed V of the inner wheel by using Equation 1. iw,target , and the target wheel speed of the inner wheel V is calculated using Equation 2. iw,target Calculate.

[0034]

number

[0035] The ESC unit 100 includes a slip error calculation unit 250. As shown in Equation 3, the slip error calculation unit 250 calculates the slip λ of the current inside wheel and the target slip λ calculated by Equation 1. target The slip error e between the calculated inner wheel target speed V iw,target At the same time, the slip error e affects the brake pressure control amount.

[0036]

number

[0037] The slip λ of the current inside wheel is calculated based on Equation 4.

[0038]

number

[0039] The ESC unit 100 calculates the target wheel speed V of the inside wheel. iw,target and the target braking torque τ target The brake pressure control amount is determined based on the determined target wheel speed V of the inside wheel. iw,target Based on this, the target braking torque τ target is determined, and the determined target braking torque τtarget Based on the target braking amount P target To this end, the ESC unit 100 includes a target braking torque calculation section 260 and a target braking amount calculation section 270.

[0040] The target braking torque calculation unit 260 calculates the target braking torque τ target Determine the target braking torque τ target is a calculation area for determining the braking torque to satisfy the target speed, and is calculated based on the correlation between energy and speed.

[0041]

number

[0042] Target braking torque τ target Once calculated, the target braking amount calculation unit 270 calculates the target braking amount P target Calculate the target braking amount P target is the target braking torque τ target This is the part where the hydraulic braking amount to satisfy the above is determined, and is determined based on wheel dynamics, which is the correlation between wheel torque and brake pressure.

[0043]

number

[0044] The ESC unit 100 applies the determined target braking amount P target The slip of the inner wheel is suppressed by applying a force to the inner wheel where slip occurs.

[0045] The brake control method according to the present invention will be described with reference to FIGS.

[0046] In step S10, the brake control method according to the present invention is started.

[0047] In step S20, a function activation request is input. The function activation request is made by operating an activation button for the brake control function according to the present invention, which is provided in the vehicle cabin. As a non-limiting example, the activation button may be turned on to enter a circuit driving mode. As another non-limiting example, the activation button may be turned on to enter a drift mode.

[0048] When a function activation request is input, the system enters a standby state for the brake control according to the present invention (S30). Subsequently, in the standby state, it is determined whether the execution conditions for the brake control according to the present invention are satisfied (S40). Even when a function activation request is input, it is determined whether hydraulic control for suppressing wheel slip is actually necessary, and the brake control according to the present invention is performed only if the execution conditions are satisfied.

[0049] As described above, the execution conditions include the turning condition C1, the acceleration condition C2, and the slip condition C3, and if each condition is met, a series of steps are performed for brake hydraulic pressure control (S60).

[0050] In step S62, a target slip λ of the inner wheel is calculated based on the tire characteristic value. target The determined target slip λ of the inside wheel is determined. target Based on this, the target wheel speed V of the inner wheel is calculated using Equation 2. iw,target is calculated (S64).

[0051] Target wheel speed of the inner wheel V iw,target Once is determined, the target braking torque τ target is calculated, and the target braking amount P target is calculated (S66).

[0052] The ESC unit 100 calculates the target braking amount P targetThe brake control according to the present invention is performed by adjusting the hydraulic braking amount of the inside wheel based on the above equation (S70).

[0053] In step S80, the conditions for terminating the brake pressure control are determined. If the function activation request is released, the brake pressure control is terminated (S90). As described above, if the activation button is turned off by the driver, the brake pressure control is terminated.

[0054] On the other hand, if any one of the turning condition C1, acceleration condition C2, and slip condition C3 is not satisfied, the brake pressure control enters a control standby state (S44). For example, if the steering angle is equal to or less than a preset reference steering angle, the control enters a control standby state regardless of whether the other conditions are satisfied, and the brake pressure control is performed when all the execution conditions are satisfied again.

[0055] The present invention improves cornering exit performance and makes drifting easier by controlling the slip of the inside wheel that occurs when a vehicle turns using brake pressure without using a mechanical device such as an LSD, thereby providing a dynamic driving environment and reducing costs, weight, and development costs and labor compared to conventional technologies.

[0056] The present invention described above is not limited to the above-described embodiments and drawings, and it will be apparent to those skilled in the art to which the present invention pertains that various substitutions, modifications, and changes are possible within the scope of the technical idea of ​​the present invention. [Explanation of symbols]

[0057] 10 Steering angle sensor 20 Lateral acceleration sensor 30 Yaw rate sensor 40 Wheel speed sensor 50 Torque sensor 60 Acceleration pedal stroke sensor 70 Functionality Request Department 100 ESC units 200 control section 210 Execution condition decision unit 220 Inner and outer ring judgment section 230 Inner wheel target slip calculation unit 240 Inner wheel target wheel speed calculation unit 250 Slip error calculation section 260 Target braking torque calculation unit 270 Target braking amount calculation section

Claims

1. receiving a function activation request; determining whether an execution condition for braking control of an inside wheel of a turning vehicle is met in response to the function activation request; and a brake pressure control step of determining and adjusting a brake pressure control amount of an inside wheel when the vehicle is turning based on a preset factor if the execution condition is satisfied, The execution condition includes an acceleration condition configured to determine whether the vehicle is accelerating, and it is determined that the acceleration condition is satisfied when a front wheel speed of the vehicle exceeds a predetermined reference front wheel speed, a driving torque of the vehicle exceeds a predetermined reference driving torque, and a driving gear of the vehicle is a predetermined reference gear.

2. The execution condition is:

2. The brake control method according to claim 1, wherein the condition is determined to be satisfied when the acceleration condition, the turning condition configured to determine whether the vehicle is turning, and the slip condition configured to determine a difference in wheel speed between the inside wheel and the outside wheel of the turn are all satisfied.

3. 3. The brake control method according to claim 2, wherein the turning condition is determined to be satisfied when the steering angle of the vehicle exceeds a predetermined reference steering angle, the lateral acceleration of the vehicle exceeds a predetermined reference lateral acceleration, and the yaw rate of the vehicle exceeds a predetermined reference yaw rate.

4. 3. The brake control method according to claim 2, wherein the slip condition is achieved when a slip difference between the inside wheel and the outside wheel exceeds a preset reference slip difference.

5. 5. The brake control method according to claim 4, wherein whether or not the wheel is an inside wheel during a turn is determined based on the yaw rate of the vehicle.

6. In the brake pressure control step, 2. The brake control method according to claim 1, wherein the target braking amount is calculated based on the target slip and the target wheel speed of the inside wheel when the vehicle is turning.

7. The brake pressure control step includes:

7. The brake control method of claim 6, further comprising the step of determining the target slip based on tire characteristics of the vehicle.

8. 8. The brake control method of claim 7, further comprising the step of calculating a target wheel speed of the inside wheel based on the target slip.

9. 9. The brake control method of claim 8, further comprising the step of calculating a target braking torque of the vehicle based on the calculated target wheel speed and a current wheel speed.

10. 10. The brake control method according to claim 9, further comprising determining a target braking amount of the brake based on the target braking torque.

11. 11. The brake control method of claim 10, wherein the hydraulic braking amount of the inside wheel is adjusted based on the target braking amount, and the adjustment of the hydraulic braking amount is performed by an electronic stability control system of the vehicle.

12. 2. The brake control method according to claim 1, wherein the brake pressure control step is terminated when the function activation request is released.

13. If at least one of the turning condition, the acceleration condition, and the slip condition is not satisfied in the brake pressure control step, the brake pressure control is terminated; 3. The brake control method according to claim 2, wherein the brake pressure control step is performed when the turning condition, the acceleration condition, and the slip condition are all satisfied again.

14. further comprising calculating a slip error between the target slip and the current slip of the inside wheel; 8. The brake control method according to claim 7, wherein the slip error is reflected in the target braking amount.

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