US-20260125039-A1 - BRAKE SYSTEM AND METHOD OF DETECTING FAILURE OF PEDAL TRAVEL SENSOR OF BRAKE SYSTEM

US20260125039A1US 20260125039 A1US20260125039 A1US 20260125039A1US-20260125039-A1

Abstract

A brake system may include at least one pedal travel sensor configured to detect a displacement of a brake pedal, and a controller is configured to acquire a pedal travel value on the basis of an output signal received from the at least one pedal travel sensor, and determine that the at least one pedal travel sensor fails on the basis that a difference value between first and second pedal travel values continuously acquired while the pedal travel value is acquired is greater than a predesignated reference value, and at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is equal to the second pedal travel value.

Inventors

Chanhee Lee

Assignees

HL MANDO CORPORATION

Dates

Publication Date: 20260507
Application Date: 20250103
Priority Date: 20241101

Claims (20)

1 . A brake system comprising: at least one pedal travel sensor configured to detect a displacement of a brake pedal; and a controller electrically connected to the at least one pedal travel sensor, wherein the controller is configured to acquire a pedal travel value on the basis of an output signal received from the at least one pedal travel sensor, and determine that the at least one pedal travel sensor fails on the basis that a difference value between first pedal travel value and second pedal travel value continuously acquired while the pedal travel value is acquired is greater than a predesignated reference value, and at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is equal to the second pedal travel value.
2 . The brake system of claim 1 , wherein the controller is configured to acquire the pedal travel value on the basis of the output signal received from the at least one pedal travel sensor in each predesignated time cycle.
3 . The brake system of claim 2 , wherein the controller is configured to increase an error count value on the basis that each of the at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is equal to a pedal travel value in an immediately previous time cycle, and determine that the at least one pedal travel sensor fails on the basis that the increased error count value is greater than a predesignated reference error count.
4 . The brake system of claim 3 , wherein the controller is configured to compare the difference value and the predesignated reference value on the basis that the second pedal travel value is acquired in a second cycle continuing to a first cycle in which the second pedal travel value is acquired, and change a flag, which indicates a non-normal state of the at least one pedal travel sensor, to a set state and set the error count to 0 on the basis that the difference value is greater than the predesignated reference value.
5 . The brake system of claim 3 , wherein the controller is configured to increase the error count value further on the basis that a flag is a set state.
6 . The brake system of claim 5 , wherein the controller is configured to determine that the at least one pedal travel sensor is normal when the at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is different from the pedal travel value in the immediately previous time cycle or the flag is a non-set state while the increased error count value is equal to or smaller than the predesignated reference error count.
7 . The brake system of claim 6 , wherein the controller is configured to reset the flag and set the error count to 0 when the at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is different from the pedal travel value in the immediately previous time cycle or the flag is the non-set state while the increased error count value is equal to or smaller than the predesignated reference error count.
8 . The brake system of claim 6 , wherein the controller is configured to determine that the at least one pedal travel sensor is normal when the difference value is equal to or smaller than the predesignated reference value.
9 . The brake system of claim 8 , wherein the at least one pedal travel sensor comprises a first pedal travel sensor, a second pedal travel sensor, and a third pedal travel sensor, and wherein the controller is configured to perform additional failure diagnosis on the first pedal travel sensor, the second pedal travel sensor, and the third pedal travel sensor on the basis of comparison between a pedal travel value of the first pedal travel sensor, a pedal travel value of the second pedal travel sensor, and a pedal travel value of the third pedal travel sensor when the first pedal travel sensor, the second pedal travel sensor, and the third pedal travel sensor are determined as being normal.
10 . The brake system of claim 9 , wherein the controller is configured to determine that the third pedal travel sensor fails on the basis that a difference value between the pedal travel value of the first pedal travel sensor and the pedal travel value of the second pedal travel sensor is equal to or smaller than a predesignated reference difference value, and a difference value between the pedal travel value of the third pedal travel sensor and each of the pedal travel value of the first pedal travel sensor and the pedal travel value of the second pedal travel sensor is greater than the predesignated reference difference value.
11 . A method of detecting a failure of a pedal travel sensor of a brake system, the method comprising: acquiring a pedal travel value on the basis of an output signal received from at least one pedal travel sensor configured to detect a displacement of a brake pedal; and determining that the at least one pedal travel sensor fails on the basis that a difference value between first pedal travel value and second pedal travel value continuously acquired while the pedal travel value is acquired is greater than a predesignated reference value, and at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is equal to the second pedal travel value.
12 . The method of claim 11 , wherein the acquiring of the pedal travel value on the basis of the output signal received from the at least one pedal travel sensor is performed in each predesignated time cycle.
13 . The method of claim 12 , further comprising: increasing an error count value on the basis that each of the at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is equal to a pedal travel value in an immediately previous time cycle, wherein the determining that the at least one pedal travel sensor fails is performed on the basis that the increased error count value is greater than a predesignated reference error count.
14 . The method of claim 13 , further comprising: comparing the difference value and the predesignated reference value on the basis that the second pedal travel value is acquired in a second cycle continuing to a first cycle in which the second pedal travel value is acquired; and changing a flag, which indicates a non-normal state of the at least one pedal travel sensor, to a set state and setting the error count to 0 on the basis that the difference value is greater than the predesignated reference value.
15 . The method of claim 13 , wherein the increasing of the error count value is performed on the basis that a flag is a set state.
16 . The method of claim 15 , further comprising: determining that the at least one pedal travel sensor is normal when the at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is different from the pedal travel value in the immediately previous time cycle or the flag is a non-set state while the increased error count value is equal to or smaller than the predesignated reference error count.
17 . The method of claim 16 , further comprising: resetting the flag and setting the error count to 0 when the at least one pedal travel value, which is continuously acquired after the second pedal travel value is acquired, is different from the pedal travel value in the immediately previous time cycle or the flag is the non-set state while the increased error count value is equal to or smaller than the predesignated reference error count.
18 . The method of claim 11 , further comprising: determining that the at least one pedal travel sensor is normal when the difference value is equal to or smaller than the predesignated reference value.
19 . The method of claim 18 , wherein the at least one pedal travel sensor comprises a first pedal travel sensor, a second pedal travel sensor, and a third pedal travel sensor, and wherein the method of detecting a failure of a pedal travel sensor further comprises performing additional failure diagnosis on the first pedal travel sensor, the second pedal travel sensor, and the third pedal travel sensor on the basis of comparison between a pedal travel value of the first pedal travel sensor, a pedal travel value of the second pedal travel sensor, and a pedal travel value of the third pedal travel sensor when the first pedal travel sensor, the second pedal travel sensor, and the third pedal travel sensor are determined as being normal.
20 . The method of claim 19 , wherein the performing of the additional failure diagnosis comprises determining that the third pedal travel sensor fails on the basis that a difference value between the pedal travel value of the first pedal travel sensor and the pedal travel value of the second pedal travel sensor is equal to or smaller than a predesignated reference difference value, and a difference value between the pedal travel value of the third pedal travel sensor and each of the pedal travel value of the first pedal travel sensor and the pedal travel value of the second pedal travel sensor is greater than the predesignated reference difference value.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the priority of Korean Patent Application No. 10-2024-0153524 filed on Nov. 1, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. BACKGROUND Technical Field The disclosed disclosure relates to a brake system and a method of detecting a failure of a pedal travel sensor of a brake system. Description of the Related Art A brake pedal refers to a device configured to perform braking control on a vehicle in accordance with a driver's braking intention. When a displacement of the brake pedal is detected by a pedal travel sensor provided on the brake pedal, a corresponding signal is transmitted to a brake system, such that the brake system may be used to perform braking control on the vehicle. However, when the pedal travel sensor for a brake pedal fails, the pedal travel sensor outputs an abnormal signal or outputs no signal even though the driver pushes the brake pedal, which causes a problem in that the brake system cannot perform normal braking control on the vehicle. Therefore, in the related art, a technology has been developed in which a plurality of pedal travel sensors is provided on a brake pedal to provide redundancy of the pedal travel sensor. The pedal travel sensor for a brake pedal has various channels, such as two or three channels, depending on the type of vehicle, such that signals of different pedal travel sensors are provided to a brake system for respective channels. BRIEF SUMMARY However, in the related art, in case that the number of channels of the pedal travel sensor for a brake pedal is three, there is a problem in that when fault injection is performed on two pedal travel sensors with the same pedal stroke, one normal pedal travel sensor is determined as being failed, and the two pedal travel sensors on which the fault injection is performed is determined as being normal. An external pedal travel sensor may be connected to a controller (e.g., an electronic control device (ECU)) of the brake system through a hard wire, and the hard wire may be manipulated so that a distorted signal may be inputted to the pedal travel sensor when the signal is distorted with the same format as properties of an output signal of the pedal travel sensor. In addition, in case that the pedal travel sensor outputs a signal through a single edge nibble transmission (SENT) protocol, the fault injection may be performed on the corresponding pedal travel sensor when the SENT protocol is hacked by a malicious user because the SENT protocol is an open protocol. Therefore, the inventors of the present disclosure have recognized the need to develop a new technology capable of solving the problem in that two pedal travel sensors subjected to fault injection are determined as being normal, and one actually normal pedal travel sensor is determined as being failed when the three pedal travel sensors are provided on the brake pedal. An object achieved by the disclosed disclosure is to provide a brake system, which is capable of providing a new failure diagnosis technology for a pedal travel sensor for a brake pedal, and a method of detecting a failure of a pedal travel sensor of a brake system. Another object achieved by the disclosed disclosure is to provide a brake system, which is capable of diagnosing a failure of a pedal travel sensor for a brake pedal in accordance with fault injection, and a method of detecting a failure of a pedal travel sensor of a brake system. Still another object achieved by the disclosed disclosure is to provide a brake system, which is capable of accurately identifying two pedal travel sensors, among three pedal travel sensors for a brake pedal, when detecting a failure by changing and outputting a signal with a value that cannot be outputted by physically changing output signals of the two pedal travel sensor in an allowable range (in-range), and a method of detecting a failure of a pedal travel sensor of a brake system. Yet another object achieved by the disclosed disclosure is to provide a brake system, which is capable of improving a technology in the related art that determines both two pedal travel sensors as being failed because it is impossible to determine an accurate value in case that pedal travel values acquired from output signals of the two pedal travel sensors are different from each other when detecting failures of the two pedal travel sensors for a brake pedal, and a method of detecting a failure of a pedal travel sensor of a brake system. For example, the brake system and the method of detecting a failure of a pedal travel sensor of a brake system, which improve the technology in the related art, may provide a technology capable of accurately identifying a pedal travel sensor, which outputs a signal with a value that cannot be outputted by physically changing output signals of the two pedal travel sensors in an allowable range, as a failed pedal travel se