Fault detection device for a vehicle braking system

Abstract

A method and system for determining a failure of a vehicle braking system are provided. An electronic processor obtains a brake pedal signal from a brake pedal indicating a driver's braking intention and obtains a vehicle brake response state signal from a brake system feedback sensor. The electronic processor determines a failure state when (1) the brake pedal signal indicates no movement of the brake pedal and the vehicle brake response signal indicates the occurrence of a vehicle brake response, or (2) the brake pedal signal indicates movement of the brake pedal and the vehicle brake response state signal indicates no occurrence of a vehicle brake response. The electronic processor controls the output of an audible or visual indication of the failure state and / or controls the braking operation of the vehicle in response to the failure state.

Description

Technical Field

[0001] <Field of the Invention> A vehicle brake system includes an arrangement for determining when the brake system is operating inappropriately.

Background Art

[0002] <Background> A brake-by-wire vehicle brake pedal does not utilize conventional connections to other components of the brake system, such as a mechanical connection to a vacuum brake system or a hydraulic brake system. In some brake-by-wire systems, a sensor monitors how far the driver depresses the brake pedal. This distance is used to determine the amount of braking force required. A control unit or computer then determines the required amount of hydraulic pressure and uses an electric pump to generate that pressure, for example, causing a caliper to press against a brake disk to stop the vehicle.

Disclosure of the Invention

Problems to be Solved by the Invention

[0003] <Summary> When the brake pedal is mechanically connected to other components of the braking system, the driver obtains a certain feel through the feet and legs. When there is no mechanical connection between the brake pedal and other parts of the braking system, the driver experiences a different feel. In a brake-by-wire (sometimes called fly-by-wire) vehicle brake pedal, there is a desire to reproduce or emulate the feel of the conventional connection between the brake pedal and the braking system. There are various ways to emulate this feel. Also, there is a desire to make the amount of braking force (or braking force) required through the brake-by-wire brake pedal match or correlate with the braking (or braking) actually performed by the braking system.

Means for Solving the Problem

[0004] The embodiments, aspects, and features described herein are directed, among other things, to a brake-by-wire vehicle brake pedal system that determines when the braking system is operating improperly.

[0005] One aspect includes a method for determining a failure of a vehicle braking system. The method includes receiving, from a brake pedal sensor, a brake pedal signal indicative of a driver's intent to brake, and receiving, from a braking system feedback sensor of at least one vehicle wheel of the vehicle, a vehicle braking response condition signal. The method also includes using an electronic processor to determine, based on the brake pedal signal and the vehicle braking response condition signal, that the vehicle braking system is in a failure state when (1) the brake pedal signal indicates no movement of the brake pedal and the vehicle braking response condition signal indicates the occurrence of a vehicle braking response, or (2) the brake pedal signal indicates movement of the brake pedal and the vehicle braking response condition signal indicates no occurrence of a vehicle braking response. The method also includes providing at least one selected from the group consisting of a visual or audible indicator indicative of the failure state, and controlling the operation of the vehicle in response to the failure state.

[0006] Another aspect includes a vehicle braking system for determining a failure of a vehicle braking system. The vehicle braking system includes a vehicle brake pedal sensor for providing a brake pedal signal from a brake pedal indicative of a driver's intent to brake, a braking system feedback sensor for providing a vehicle braking response condition signal, and an electronic processor. The electronic processor is configured to receive the brake pedal signal, receive the vehicle braking response condition signal, and determine that it is in a failure state when (1) the brake pedal signal indicates no movement of the brake pedal and the vehicle braking response condition signal indicates the occurrence of a vehicle braking response, or (2) the brake pedal signal indicates movement of the brake pedal and the vehicle braking response condition signal indicates no occurrence of a vehicle braking response. The electronic processor is also configured to provide at least one selected from the group consisting of an audible or visual indication of the failure state, and control of the braking operation of the vehicle in response to the failure state.

[0007] Other embodiments, features, and aspects will become apparent by considering the detailed description and the accompanying drawings.

Brief Description of the Drawings

[0008]

Figure 1

[0009]

Figure 2

[0010]

Figure 3

[0011]

Figure 4

[0012]

Figure 5

Modes for Carrying Out the Invention

[0013] Before any embodiment, aspect, or feature is described in detail, it is understood that the arrangement is not limited in application to the structures and the arrangements of components detailed in the following description or illustrated in the following drawings. Other embodiments, aspects, and features are possible and can be implemented or carried out in various ways.

[0014] Figure 1 shows a vehicle braking system 20 for a vehicle 22 including a plurality of wheels 24a, 24b, 24c, 24d. The vehicle 22 includes brakes 28a, 28b, 28c, 28d associated with each wheel.

[0015] The arrangement of FIG. 1 includes brake system feedback sensors 32a, 32b, 32c, 32d provided adjacent to each of the wheels 24a - 24d to determine the operation of the respective brakes 28a, 28b, 28c, 28d. In one embodiment, the brake system feedback sensors 32a - 32d include hydraulic pressure sensors that sense the hydraulic pressure applied to the respective brakes 28a - 28d. Other arrangements are also contemplated.

[0016] FIG. 1 also shows a brake pedal force sensor 40, a brake pedal position sensor 50, and an engine state or motor state sensor 54. The sensors 32a - 32d, 40, 50, 54 provide inputs to an electronic controller 60. The electronic controller 60 provides outputs to a brake control system 64 connected to the vehicle brakes 28a - 28d. The electronic controller 60 is also connected to a fault indicator 68 within the vehicle 22.

[0017] FIG. 2 schematically shows the electronic controller 60 in more detail. As shown in FIG. 2, the electronic controller 60 is connected to a plurality of sensors 40, 54 via a communication bus 70. The vehicle communication bus 70 can be a controller area network (``CAN'') bus, a CAN - FD (flexible data rate) bus, a Flex - Ray bus, or the like. In one embodiment, the sensors of the vehicle 22 include a brake pedal force sensor arrangement 40, a brake pedal position sensor 50, an engine state sensor or a motor state sensor 54, and brake system feedback sensors 32a - 32d.

[0018] As shown in FIG. 2, the electronic controller 60 includes an input / output interface 80, an electronic processing unit (``EPU'') or electronic processor 82, and one or more non-transitory memories or computer-readable modules such as a random access memory (``RAM'') 84 and a read-only memory (``ROM'') 88. The input / output interface 80 transmits and receives data, including data from sensors, via the communication bus 70. It should be understood that the electronic controller 60 can include multiple processors, additional computer-readable media modules, multiple input / output interfaces, and / or other additional components or modules (e.g., hardware, software, or combinations thereof).

[0019] The electronic processor 82 receives information from the input / output interface 80 and processes the information by executing one or more instructions from a software module (also referred to as a ``controller'' or ``control device''). The instructions, modules, or controllers are stored on a non-transitory computer-readable medium such as the ROM 88. The electronic controller 60 stores information (e.g., information received from the communication bus 70 or information generated by instructions or modules executed by the electronic processor 82) in the RAM 84 and retrieves it from the RAM 84. The non-transitory computer-readable medium includes volatile memory, non-volatile memory, or combinations thereof. The computer-readable medium stores operating system software, applications and / or instructions, data, or combinations thereof. Although only a single electronic processor 82, RAM 84, ROM 88, and input / output interface 80 are shown in FIG. 2, it should be understood that the electronic controller 60 can include multiple processing units, memory modules, and / or input / output interfaces.

[0020] Although the electronic controller 60 is illustrated as a stand-alone component in FIG. 1-2, in some embodiments, the electronic controller 60 can be combined with other vehicle components. For example, the electronic controller 60 can be connected to other ECUs or controllers, or additional sensors or different sensors. Also, the electronic controller 60 can perform multiple functions in addition to brake control and fault detection.

[0021] FIG. 3 shows a vehicle brake pedal 90 including a brake pedal force sensor arrangement 102. The brake pedal force sensor arrangement 40 includes a first brake pedal force sensor 94 and a second redundant brake pedal force sensor 98.

[0022] <Fault detection operation>

[0023] FIG. 4 is a flowchart 100 showing the operation of the fault detection arrangement of the vehicle brake system 20. In operation, the electronic processor 82 of the electronic controller 60 is configured to execute an algorithm or program received from memories 84, 88.

[0024] As shown in FIG. 4, at step 104, the electronic processor 82 receives a brake pedal signal from a vehicle brake pedal sensor via the communication bus 70 and the input / output interface 80. The electronic processor 82 proceeds to step 108. In one embodiment, the vehicle brake pedal sensor is the brake pedal position sensor 50 and the brake pedal signal is the brake pedal position signal.

[0025] At step 108, the electronic processor 82 receives a vehicle brake response state signal from one or a combination of the brake system feedback sensors 32a - 32d via the communication bus 70 and the input / output interface 80 or other connections. Thereafter, the electronic processor 82 proceeds to decision step 112.

[0026] In determination step 112, the electronic processor 82 determines whether the brake pedal signal from the brake pedal position indicates movement of the pedal. If the brake pedal signal indicates movement of the pedal / brake, the electronic processor 82 proceeds to determination step 120. If the brake pedal signal does not indicate the driver's intention to brake, the electronic processor proceeds to step 124.

[0027] If braking is occurring, the electronic processor proceeds to determination step 120. In determination step 120, the electronic processor 82 determines whether the vehicle brake response state signals from the plurality of brake system feedback sensors 32a - 32d indicate the occurrence of braking. When the vehicle brake response state signals match the brake as in the brake pedal signal, the electronic processor 82 returns to step 104 and repeats the steps. When the vehicle brake response state signals do not indicate the occurrence of braking in determination step 120, the electronic processor proceeds to step 130, indicating a fault state of the vehicle brake system. The fault state signal is indicated by the fault indicator 68. The electronic processor 82 supplies a signal to the fault indicator 68 via the input / output interface 80 and the communication bus 70 in one arrangement.

[0028] Returning to determination step 112, if the brake pedal signal does not indicate movement of the brake pedal, the electronic processor 82 proceeds to determination step 124. In determination step 124, the electronic processor 82 determines whether the vehicle brake response state signals from one or more of the brake system feedback sensors 32a - 32d indicate the occurrence of vehicle braking. If no vehicle braking is occurring and thus there is no movement of the pedal, the electronic processor 82 returns to step 124 and repeats the steps. If there is no movement of the pedal and vehicle braking is occurring in step 124, the electronic processor 82 proceeds to step 130.

[0029] In step 130, the electronic processor outputs a fault status signal. The fault status signal is indicated by the fault indicator 68. The fault indicator signal is at least one selected from the group consisting of a fault indicator signal visually provided on the dashboard display and an audible chime or voice alarm provided via the vehicle sound system. In one embodiment, both an audible alarm and a visual alarm are provided.

[0030] In addition to, or instead of, the fault status indication in step 130, in another arrangement, the electronic processor 82 also provides a vehicle control signal for controlling the operation of the vehicle to minimize speed and / or ultimately stop the vehicle at an appropriate location due to a fault condition of the vehicle brake system 20.

[0031] Other arrangements are also conceivable. In one arrangement, the vehicle brake response status signal is sensed by brake system feedback sensors 32a - 32d of a hydraulic brake system disposed on at least one of the vehicle wheels 24a - 24d. In another arrangement, the vehicle brake response status signal is sensed by brake system feedback sensors 32a - 32d that are part of an electromechanical brake system disposed on at least one of the vehicle wheels 24a - 24d.

[0032] In one arrangement, the brake system feedback sensors 32a - 32d include brake pressure sensors. In another arrangement, the brake system feedback sensors are multiple brake system feedback sensors 32a - 32d at each of the vehicle brakes 28a - 28d, and the average of the sensed vehicle brake response status signals is determined.

[0033] In one arrangement, the vehicle 22 is one selected from the group consisting of an electric vehicle, an internal combustion engine vehicle, and a hybrid vehicle. In another embodiment, the vehicle is an autonomous vehicle.

[0034] FIG. 5 shows a block diagram 140 of another arrangement of the brake pedal force sensor arrangement 40 shown in FIG. 3, including a pair of brake pedal force sensors 94, 98. The outputs of the first brake pedal force sensor 94 and the second redundant brake pedal force sensor 98 are supplied to an electronic processor 182. The outputs are provided either by direct connection or via a communication bus. The electronic processor 182 compares the brake pedal force signals. If the signals are not similar, the electronic processor 182 provides a signal indicating a failure of the brake pedal force sensors 94, 98 to a fault status indicator 168. In response, a visual or audible indicator indicating the fault status is provided. The output can identify that the fault status is directed at the brake force sensors 94, 98. In other arrangements, the operation of the vehicle is controlled and ultimately terminated in response to the fault status. In conclusion, in this arrangement, a fault indication of the brake pedal force sensor arrangement is provided when the first brake pedal force sensor 94 and the second brake pedal force sensor 98 do not provide similar brake pedal force signals. Thus, the electronic processor 182 is configured to provide a fault indication of the brake pedal force sensor arrangement 140 when the brake pedal force signal from the first brake pedal force sensor 94 is different from the brake pedal force signal from the second brake pedal force sensor 98.

[0035] In another arrangement, the method includes a vehicle brake pedal position sensor 50, one or more brake pedal force sensors 94, 98, and providing an engine status signal or a motor status signal from an engine status sensor or a motor status sensor 54. In one feature, the electronic processors 82, 182 determine when the vehicle engine or vehicle motor is in a rest state from the engine status signal or the motor status signal from the engine status sensor or the motor status sensor 54. The engine status signal or the motor status signal can be visually displayed or provided on the vehicle dashboard. An audible engine status signal or motor status signal can also be provided by the electronic processors 82, 182.

[0036] Also, it should be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of "including", "comprising", or "having" and variations thereof herein means including the items listed hereinafter, their equivalents, and additional items. The terms "attached", "connected", and "coupled" are used in a broad sense and include both direct and indirect attachment, connection, and coupling. Further, "connected" and "coupled" are not limited to physical or mechanical connections or couplings and can include electrical connections or couplings, whether direct or indirect. Also, electronic communication and notification can be performed using known means such as wired connections, wireless connections, etc.

[0037] It should also be noted that multiple hardware and software-based devices, as well as multiple different structural components, can be used to implement the embodiments. In addition, the embodiments can include hardware, software, and electronic components or modules and, for purposes of discussion, can be illustrated and described as if most of the components were implemented solely in hardware. However, those skilled in the art will recognize that, in at least one embodiment, the electronic-based aspects of the embodiments can be implemented in software (e.g., stored on a non-transitory computer-readable medium) executable by one or more processors upon reading this detailed description. Thus, it should be noted that multiple hardware and software-based devices, as well as multiple different structural components, can be utilized to implement the embodiments. For example, the "electronic processor" and "controller" described herein can include standard processing components such as one or more processors, one or more memory modules including a non-transitory computer-readable medium, one or more input / output interfaces, and various connections (e.g., a system bus) connecting the components. Software can include instructions and algorithms for performing the methods described herein.

Claims

1. A method for determining a fault state of a vehicle braking system, comprising: receiving a brake pedal signal indicating a driver's braking intention from a brake pedal sensor; receiving a vehicle brake response state signal from at least one brake system feedback sensor of a wheel of the vehicle; using an electronic processor, based on the brake pedal signal and the vehicle brake response state signal, to determine that the vehicle braking system is in a fault state when (1) the brake pedal signal indicates no movement of the brake pedal and the vehicle brake response state signal indicates the occurrence of a vehicle brake response, or (2) the brake pedal signal indicates movement of the brake pedal and the vehicle brake response state signal indicates no occurrence of a vehicle brake response; providing at least one selected from the group consisting of visual or audible indicators indicating the fault state, and controlling the operation of the vehicle according to the fault state.

2. The method according to claim 1, wherein the brake pedal signal is a brake pedal position signal, and the brake pedal sensor is a vehicle brake pedal position sensor for sensing the brake pedal position.

3. The method according to claim 2, wherein the vehicle brake response state signal is sensed by the brake system feedback sensor of a hydraulic brake system disposed on the at least one wheel of the vehicle.

4. The method according to claim 1, wherein the brake system feedback sensor is one of a plurality of brake system feedback sensors disposed on each wheel of the vehicle.

5. The method according to claim 4, wherein the brake system feedback sensor includes a brake pressure sensor.

6. The method according to claim 1, wherein the vehicle is one selected from the group consisting of an electric vehicle, an internal combustion engine vehicle, and a hybrid vehicle.

7. The method according to claim 1, further comprising providing a brake pedal force signal from a brake pedal force sensor disposed within the brake pedal, and providing an engine state signal or a motor state signal from an engine state sensor or a motor state sensor, wherein the brake pedal sensor is provided by a vehicle brake pedal position sensor.

8. The method according to claim 7, comprising the step of determining, using an electronic processor, when the vehicle engine or motor is in a rest state from the engine state signal or the motor state signal.

9. Providing a brake pedal force sensor arrangement including a first brake pedal force sensor and a second redundant brake pedal force sensor disposed within the brake pedal, the method including using the electronic processor to provide a fault indication of the brake pedal force sensor arrangement when the first brake pedal force sensor and the second brake pedal force sensor do not provide similar brake pedal force signals.

10. The vehicle brake response state signal sensed by the brake system feedback sensor is part of an electromechanical brake system disposed on at least one of the wheels of the vehicle, according to the method of claim 1.

11. A vehicle brake system for determining a fault state of a vehicle brake system, the vehicle brake system comprising: A vehicle brake pedal sensor for supplying a brake pedal signal indicating a driver's braking intention from the brake pedal; A brake system feedback sensor for providing a vehicle brake response state signal; Receiving the brake pedal signal and receiving the vehicle brake response state signal; Determining a fault state when (1) the brake pedal signal indicates no movement of the brake pedal and the vehicle brake response state signal indicates the occurrence of a vehicle brake response, or (2) the brake pedal signal indicates movement of the brake pedal and the vehicle brake response state signal indicates the non-occurrence of a vehicle brake response; and An electronic processor configured to provide at least one selected from the group consisting of an audible or visual indication of the fault state and control of the braking operation of the vehicle in response to the fault state.

12. The vehicle brake system according to claim 11, wherein the vehicle brake pedal sensor includes a vehicle brake pedal position sensor.

13. The vehicle brake system according to claim 12, wherein the brake system feedback sensor is disposed on at least one of the wheels of the vehicle.

14. The brake system feedback sensor is one of a plurality of brake system feedback sensors arranged on each wheel of the vehicle, the vehicle brake system according to claim 11

15. The brake system feedback sensor includes a brake pressure sensor for a hydraulic brake system, the vehicle brake system according to claim 14

16. The brake system feedback sensor includes a brake pressure sensor for an electromechanical brake system, the vehicle brake system according to claim 14

17. The vehicle is one selected from the group consisting of an electric vehicle, an internal combustion engine vehicle, and a hybrid vehicle, the brake system for a vehicle according to claim 11

18. The brake pedal sensor includes a vehicle brake pedal position sensor, and the vehicle brake system A brake pedal force sensor arranged in the brake pedal that provides a brake pedal force signal to the electronic processor An engine state sensor or a motor state sensor that provides an engine state signal or a motor state signal to the electronic processor, the vehicle brake system according to claim 11

19. The electronic processor is configured to determine when the vehicle engine or the vehicle motor is in a resting state from the engine state signal or the motor state signal, the vehicle brake system according to claim 18

20. The vehicle brake system Includes a brake pedal force sensor including a first brake pedal force sensor and a second redundant brake pedal force sensor arranged in the brake pedal The electronic processor is configured to provide a fault indication of the brake pedal force sensor arrangement when the brake pedal force signal from the first brake pedal force sensor is different from the brake pedal force signal from the second brake pedal force sensor, the vehicle brake system according to claim 12

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