Method and system for assisting braking of a vehicle

Abstract

The present disclosure proposes a method and system for assisting braking of a vehicle in the event of brake pedal slip, in which a control module (1) is embedded as a brake pedal slip assist (BPSA) in an electronic stability program (ESP) (10) to assist braking of the vehicle as a value-added function in the event of brake pedal slip. A condition of brake pedal slip is detected based on the pressure gradient being greater than a threshold pressure gradient. In a case where brake pedal slip is detected, brake pressure is applied to decelerate the vehicle. In the event that the driver resumes braking, a brake pedal slip assist (BPSA) function of the control module (1) is deactivated.

Description

[0001] The following specification describes and defines the nature of the present invention and the manner of carrying it out. Technical Field

[0002] The present disclosure relates to a method and system for assisting in braking a vehicle, and more particularly to a method and system for assisting in braking a vehicle in the event of a slipping brake pedal. Background Art

[0003] According to 2019 data from the National Highway Traffic Safety Administration (an agency of the U.S. Department of Transportation, Federal Government), 24% of total accidents occurred due to driver pedal errors. Brake pedal slippage is a pedal error where the driver's foot slips off the brake pedal when applying the brake. In one scenario when applying the brakes, the driver's foot slips when the driver accidentally steps on the edge of the brake pedal. In another scenario, the driver's foot gradually slips due to less grip between the foot and the brake pedal.

[0004] In the prior art DE102009053824A1, a hydraulic brake assist control method for a vehicle includes: increasing the brake pressure by a low pressure supplied to a booster; and adapting a gradient threshold to the low pressure supplied to the brake booster and / or the ambient air pressure. The method includes: automatically adjusting, by brake assist, the brake pressure acting on the brakes of the vehicle; and deriving a brake pressure gradient from the characteristics of the brake pressure. When the brake pressure gradient is higher than the brake pressure gradient threshold, brake assist is enabled. The brake pressure is increased by the low pressure supplied to the brake booster. The brake pressure gradient threshold is adapted to the low pressure supplied to the brake booster and / or the ambient air pressure.

[0005] Available prior art assists braking when insufficient brake pressure is applied at the moment of emergency braking. However, there is no solution to detect a brake pedal slippage situation to activate the brake assist system. Therefore, effective brake pedal slippage assistance is needed, which can be an independent system or can be embedded as a value-added function in the vehicle's ESP. Brief Description of the Drawings

[0006] Embodiments of the present invention are described with reference to the following drawings:

[0007] Figure 1 A system for assisting in braking a vehicle in the event of a slipping brake pedal is depicted.

[0008] Figure 2 A flowchart of a method for assisting in braking a vehicle in the event of a slipping brake pedal is depicted. Detailed Description

[0009] Figure 1Describes a system for assisting the braking of a vehicle in the case of a slipping brake pedal.

[0010] Reference Figure 1 , the control module (1) is embedded as a Brake Pedal Slipping Assist (BPSA) in the Electronic Stability Program ESP (10) to assist in braking the vehicle in the case of a slipping brake pedal as a value-added function. In an alternative embodiment, the control module may exist independently, having a computing processor and a storage unit that execute the stored program. The ESP (10) identifies critical driving states and stabilizes the vehicle through individual wheel braking and engine control interventions without the need to activate the brakes. The ESP system is developed to help the driver avoid the risk of losing control of the vehicle's stability due to understeering or oversteering during turning. The ESP has two active safety systems: the Anti-lock Braking System (ABS) (7) and the Traction Control System (TCS) (8). The ABS (7) prevents the wheels from locking during braking, and the TCS (8) prevents the wheels from spinning during starting and acceleration. The ESP receives (in an alternative embodiment, the control module (1) receives the input) inputs from the wheel speed sensors (11), the inertial sensors (12), the accelerator pedal position sensor (13), the brake light switch (14), the steering angle sensor (15), and the measured engine torque (16).

[0011] The wheel speed sensors (11) measure the wheel speed in a non-contact manner via a magnetic field. The inertial sensors (12) are used to measure translational and rotational accelerations. The accelerator pedal position sensor (13) senses the accelerator position during the depression of the accelerator pedal. The brake light switch (14) controls the brake lights to indicate when braking is applied in the vehicle. The steering angle sensor (15) measures the steering wheel position angle and the steering rate, and the engine torque (16) is calculated by the engine control unit using a torque sensor. The ESP also has a human-machine interface (5) to connect to the output devices in the instrument cluster (6). In addition, a diagnostic system (9) may be provided to detect any errors and repair the entire brake pedal slipping assist system.

[0012] Reference Figure 1 , what is disclosed is a control module (1) for assisting the braking of a vehicle in the case of a slipping brake pedal, the control module being configured to:

[0013] - Detect a signal from the master cylinder pressure sensor (2);

[0014] - Estimate the braking pressure;

[0015] - Estimate the braking time;

[0016] - Detect a situation where the brake pedal slips, where the situation of the brake pedal slipping is detected based on a pressure gradient being greater than a threshold pressure gradient;

[0017] - Communicate with the braking system (3) to dynamically apply the braking pressure when the pressure gradient is greater than the threshold pressure gradient;

[0018] - Communicate with the braking system (3) to provide deceleration of the vehicle at a constant rate if the vehicle speed is greater than a threshold speed; and

[0019] - Deactivate the brake pedal slip assist when the driver resumes braking.

[0020] The pressure gradient is calculated by the following steps: obtaining the difference between the braking pressure obtained from the master cylinder pressure sensor (2) during braking application and the braking pressure obtained from the master cylinder pressure sensor when the brake pedal is released; and dividing the difference thus obtained by the braking time.

[0021] The threshold pressure gradient is obtained based on comparing: a graph of the relationship between the pressure gradient value and the braking pressure during an intentional pedal release; and a graph of the relationship between the pressure gradient value and the braking pressure during a pedal slip situation. The control module (1) communicates with the human-machine interface (5) to provide a BPSA enable indication to an output device in the instrument cluster (6).

[0022] The control module (1) is embedded in the ESP to assist in braking the vehicle as an added value function in the case of brake pedal slip. The control module (1) communicates with the master cylinder pressure sensor (2). The master cylinder pressure sensor (2) detects the braking fluid pressure difference in the hydraulic system. The control module calculates the pressure gradient based on the pressure difference between the situation of applying the brake and releasing the brake pedal within the unit braking time (the time taken from stepping on the pedal to releasing the pedal). Then, the control module compares the pressure gradient value thus calculated with the threshold pressure gradient value. The same threshold pressure gradient value is pre-calculated, vehicle-specific, and fed into the system. The threshold pressure gradient is obtained based on comparing: a graph of the relationship between the pressure gradient value and the braking pressure during an intentional pedal release; and a graph of the relationship between the pressure gradient value and the braking pressure during a pedal slip situation.

[0023] If the pressure gradient value calculated by the control module is greater than the threshold pressure gradient value, it is considered that a situation of brake pedal slip is detected. Once a situation of brake pedal slip is detected, the control module interacts with the braking system (3) to apply the braking pressure to the brake disc (4). The braking system (3) uses a hydraulic braking mechanism, where the braking fluid is used to transfer pressure to the brake disc (4).

[0024] According to one aspect of the present invention, the "braking pressure" applied when a brake pedal slip condition is detected can be dynamic in nature. For example, when a brake pedal slip condition is detected, the braking pressure for the vehicle can be dynamically applied to provide a deceleration increasing from 0.1g to 0.3g. The magnitude of the dynamic braking pressure to be applied can be customized for the vehicle and fed into the system.

[0025] According to another aspect of the present invention, the "braking pressure" applied when a brake pedal slip condition is detected can be constant depending on the vehicle speed. In the case where a brake pedal slip is detected and the vehicle speed is greater than a threshold vehicle speed, a constant braking pressure can be applied. For example, for a moving vehicle in which a brake pedal condition is detected and the vehicle speed is greater than the threshold vehicle speed of 50 kilometers per hour, a constant braking pressure can be applied to decelerate the vehicle at 0.3g. The magnitude of the constant braking pressure to be applied and the threshold vehicle speed (above which the constant braking pressure will be applied) can be customized for the vehicle and fed into the system.

[0026] According to another aspect of the present invention, once the driver resumes braking the vehicle, the brake pedal slip assist function of the control module (1) is deactivated.

[0027] It should be noted that the control module (1) includes a computing processor for executing the stored programs and a storage unit. The storage unit stores programs, reference values, and inputs from sensors to implement the present invention.

[0028] Reference Figure 2 , Figure 2 depicts a flowchart of a method for assisting the braking of a vehicle in the case of brake pedal slip.

[0029] Disclosed is a method for assisting the braking of a vehicle in the case of brake pedal slip, the method comprising the steps of:

[0030] - Detecting the condition of the brake pedal slip (100), wherein the condition of the brake pedal slip is detected based on a pressure gradient being greater than a threshold pressure gradient;

[0031] - Applying a braking pressure (200) to decelerate the vehicle in the case where the brake pedal slip is detected; and

[0032] - Deactivating the brake pedal slip assist (BPSA) (300) in the case where the driver resumes braking.

[0033] The pressure gradient (100a) is calculated by the following steps: obtaining the difference between the braking pressure obtained from the master cylinder pressure sensor (2) during the application of braking and the braking pressure obtained from the master cylinder pressure sensor when the brake pedal is released; and dividing the difference thus obtained by the braking time.

[0034] The threshold pressure gradient (100b) is obtained based on comparing the following: a graph of the relationship between the pressure gradient value and the braking pressure during an intentional pedal release; and a graph of the relationship between the pressure gradient value and the braking pressure during a pedal slip situation.

[0035] If the pressure gradient is greater than the threshold pressure gradient, the braking pressure is applied dynamically (200a); and if the vehicle speed is greater than the threshold speed, the braking pressure is applied at a constant rate (200b).

[0036] Reference Figure 2 The first step, with reference to, is to detect a situation of brake pedal slip (100). To detect a situation of brake pedal slip, the pressure gradient is compared with the threshold pressure gradient. The pressure gradient (100a) is calculated based on the pressure difference between the application of braking and the release of the brake pedal within the unit braking time (the time taken from pressing the pedal to releasing the pedal). The calculated pressure gradient value is compared with the threshold pressure gradient value. The same threshold pressure gradient value is pre-calculated, vehicle-specific, and fed into the system. The threshold pressure gradient (100b) is obtained based on comparing the following: a graph of the relationship between the pressure gradient value and the braking pressure during an intentional pedal release; and a graph of the relationship between the pressure gradient value and the braking pressure during a pedal slip situation. If the pressure gradient value calculated by the control module is greater than the threshold pressure gradient value, it is considered that a situation of brake pedal slip has been detected.

[0037] Once a situation of brake pedal slip has been detected, the next step is then to apply a braking pressure (200) to decelerate the vehicle. If the pressure gradient is greater than the threshold pressure gradient, the braking pressure is applied dynamically (200a); and in the case where the vehicle speed is greater than the threshold speed, the braking pressure is applied at a constant rate (200b). The "braking pressure" applied when a situation of brake pedal slip is detected can be dynamic. For example, when a situation of brake pedal slip is detected, the braking pressure for the vehicle can be applied dynamically to provide a deceleration that increases incrementally from 0.1g to 0.3g. The magnitude of the dynamic braking pressure to be applied can be customized for the vehicle and fed into the system.

[0038] The "braking pressure" applied when a brake pedal slip condition is detected can be constant, depending essentially on the vehicle speed. A constant braking pressure can be applied when a brake pedal slip condition is detected and the vehicle speed is greater than a threshold vehicle speed. For example, for a moving vehicle in which a brake pedal condition is detected and the vehicle speed is greater than a threshold vehicle speed of 50 kilometers per hour, a constant braking pressure can be applied to decelerate the vehicle at 0.3g. The magnitude of the constant braking pressure to be applied and the threshold vehicle speed (above which the constant braking pressure will be applied) can be customized for the vehicle and fed into the system. Once the driver resumes braking the vehicle, the brake pedal slip assist is deactivated (300).

[0039] The present disclosure advantageously assists in braking a vehicle in the event of a brake pedal slip. The system takes over the task of braking the vehicle until the time when the driver regains control of the brakes. The present disclosure has broad applications in relation to preventing accidents and improving road safety.

Claims

1. A method for assisting vehicle braking in case of brake pedal slip, the method comprising the steps of: - Detect the situation where the brake pedal slips (100), where The case of brake pedal slip is detected based on a pressure gradient being greater than a threshold pressure gradient; - Applying a braking pressure (200) to decelerate the vehicle in case of detecting the brake pedal slip; And - Deactivating the brake pedal slip assist (BPSA) (300) in case the driver resumes braking.

2. The method for assisting vehicle braking in case of brake pedal slippage according to claim 1, wherein, The pressure gradient (100a) is calculated by the following steps: obtaining the difference between the braking pressure obtained from the master cylinder pressure sensor during application of braking and the braking pressure obtained from the master cylinder pressure sensor when the brake pedal is released; And dividing the difference thus obtained by the braking time.

3. The method for assisting vehicle braking in case of brake pedal slippage according to claim 1, wherein, The threshold pressure gradient (100b) is obtained based on comparing the following: - A graph of the relationship between the pressure gradient value and the braking pressure during a deliberate pedal release; And - A graph of the relationship between the pressure gradient value and the braking pressure during a pedal slip situation.

4. The method for assisting vehicle braking in case of brake pedal slip according to claim 1, wherein, - If the pressure gradient is greater than the threshold pressure gradient, the braking pressure is dynamically applied (200a); And - If the vehicle speed is greater than a threshold speed, the braking pressure is applied at a constant rate (200b).

5. A control module (1) for assisting vehicle braking in case of brake pedal slip, the control module being configured to: - Detect a signal from the master cylinder pressure sensor (2); - Estimate the braking pressure; - Estimate the braking time; - Detect the situation where the brake pedal slips, where The case of brake pedal slip is detected based on a pressure gradient being greater than a threshold pressure gradient; - Communicate with the braking system (3) to apply the braking pressure dynamically when the pressure gradient is greater than the threshold pressure gradient; - Communicate with the braking system (3) to provide deceleration of the vehicle at a constant rate if the vehicle speed is greater than the threshold speed; And - Deactivate the brake pedal slip assist when the driver resumes braking.

6. The control module (1) for assisting vehicle braking in case of brake pedal slip according to claim 5, calculates the pressure gradient by the following steps: obtaining the difference between the braking pressure obtained from the master cylinder pressure sensor (2) during application of braking and the braking pressure obtained from the master cylinder pressure sensor when the brake pedal is released; and dividing the difference thus obtained by the braking time.

7. The control module (1) for assisting the braking of a vehicle in the case of a skidding brake pedal according to claim 5, wherein, The threshold pressure gradient is obtained based on comparing the following: - A graph of the relationship between the pressure gradient value and the braking pressure during a deliberate pedal release; and - A graph of the relationship between the pressure gradient value and the braking pressure during a pedal slip situation.

8. The control module (1) for assisting the braking of a vehicle in the case of a skidding brake pedal according to claim 5, wherein, The control module communicates with a human-machine interface (5) to provide a brake pedal slip assist (BPSA) enable indication to an output device in the instrument cluster (6).

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