How to operate the brake system

Abstract

To provide a method for operating a brake device of a vehicle having a main brake system and a backup brake system.SOLUTION: A brake device includes: a main brake system control unit capable of operating or stopping operation of a brake function of a main brake system; and a backup brake system control unit connected to the main brake system control unit and capable of operating or stopping operation of a brake function of a backup brake system. The method includes the steps of: detecting a defect of the brake function; performing position specification of the defect in the brake device; classifying the defect; and delivering the brake function detected to be defective in the main brake system to the backup brake system when the defect relates only to the main brake system, and thereby allowing the brake function to remain executable by the backup brake system.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for operating a vehicle's braking system and a control device for monitoring the corresponding braking function. [Background technology]

[0002] Today's vehicles have a variety of braking functions, such as ABS, ESP, and brake boosters, which enable various braking processes. Some of these braking functions are implemented by unique components that increase and regulate pressure in the hydraulic system of the vehicle's wheel brakes, thereby braking the corresponding wheels. To ensure sufficient braking safety, various braking functions are configured redundantly. This means that if one component fails, at least the most critical function of that component will be maintained completely or temporarily.

[0003] To avoid redundant systems, various braking functions of a component are fully or temporarily taken over by other components of the braking system that would normally perform different braking functions. In this case, such takeover of the most critical braking function is done automatically to minimize the time of failure (Ausfall) of the critical braking function. Similarly, other less critical braking functions can be automatically shut down.

[0004] Patent Document 1 discloses a method for operating a brake system for a vehicle. The brake system comprises an electronic control device and a pneumatic control device for controlling brake pressure. In this method, a defect (Fehler) in the electronic control device is classified, and if the defect signal is a defect signal of a first defect category, the system is switched to the pneumatic control device. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2017 / 001315 [Patent Document 2] German Patent Application Publication No. 102019208402 Specification [Overview of the Initiative]

[0006] Embodiments of the present invention can improve the operation of a braking system having a main brake system and a backup brake system. The invention described below is based on the following considerations: Switching to a redundant brake system may often be correct, but this does not necessarily mean that the corresponding braking function will remain operational. Therefore, when switching to a redundant brake system, the corresponding braking function may not be operational. Unless another redundant system exists, it may then be necessary to deactivate this braking function. [Means for solving the problem]

[0007] Therefore, the present invention provides a method for operating a vehicle brake system comprising: a main brake system; a backup brake system capable of taking over the braking function of the main brake system; a main brake system control unit capable of activating or deactivating the braking function of the main brake system; and a backup brake system control unit connected to the main brake system control unit, capable of activating or deactivating the braking function of the backup brake system.

[0008] In that case, the method includes the steps of detecting a defect in the braking function of the brake system, locating the defect within the brake device, classifying the corresponding defects relating to the brake function and brake system, and transferring the brake function detected as defective in the main brake system to the backup brake system if the defect relates only to the main brake system, thereby ensuring that the brake function remains operational by the backup brake system.

[0009] In this case, the main brake system is a brake system whose primary task is to perform specific braking functions, such as detecting a driver's brake request via a pedal sensor and, as a result, increasing the pressure in the hydraulic system. In contrast, the backup brake system may also be a main brake system with the potential to increase pressure, but this main brake system primarily performs braking functions other than those of the main brake system, such as ABS and ESP, as its primary task. In this case, the backup brake system can be a redundant system for the main brake system that can take over or temporarily perform various functions of the main brake system in the event of a failure of the main brake system. In this case, each brake system has its own control unit in which the method according to the present invention is implemented. These control units are connected to each other so that they can communicate with each other whether the braking function remains operational when it is handed over to the backup brake function.

[0010] In this case, a malfunction (Fehlfunktion) of a component of the brake system is understood as a defect in the sense of the present invention, and the cause of the malfunction may be internal or external to the brake system. An example of an external cause is, for example, a decrease in the electrical performance of the energy supply unit (e.g., wiring resistance or transition resistance). This defect leads to the inability to adequately perform the corresponding braking function. After the defect is detected or confirmed, it is subsequently located. In this case, classification is understood as a process in which the effect of the defect on a specific function within the brake system is re-examined. Correspondingly, it can then be determined whether it is meaningful to hand over to a backup system.

[0011] This has the advantage of allowing verification of whether the brake system is capable of performing the braking function before the backup brake system is activated. Similarly, it has the advantage of avoiding operating conditions that would lead to failure due to increased power consumption and subsequent voltage drops due to wiring resistance, by transferring this "high-current function" to the backup brake. Thus, time is saved for switching and subsequently for verifying any defects. In addition, the safety of the braking system is improved, and all "low-current functions" (e.g., pedal sensors) remain available.

[0012] In a preferred embodiment of the present invention, a defect is detected before a failure of the braking function of the brake system occurs if the measured parameter exceeds a threshold defined for that purpose. This means that a future failure of the braking function is predicted while the system is still operating normally. This can be detected, for example, by measuring wiring resistance or transition resistance. As electrical wiring ages, its condition deteriorates, thereby increasing its wiring resistance. This means that, especially in high-voltage applications, once a certain resistance is reached, the system can no longer provide the necessary power. This can be measured at an earlier stage. For a corresponding measurement method, please refer to Patent Document 2.

[0013] This method step has the advantage of allowing switching to the backup brake system before a failure occurs. Similarly, if the parameters in the backup brake system exceed a threshold, this braking function can be directly turned off before it fails shortly after switching to the backup brake system.

[0014] In particular, defects in the brake system's braking function are detected before they actually occur by a machine learning model trained specifically for this purpose. For example, pressure, voltage, resistance, and impedance values ​​of various wiring are read into the machine learning model. This data is processed by the machine learning model, making it possible to predict the likelihood of an impending brake failure.

[0015] In a preferred embodiment of the present invention, if a defect affects both the main brake system and the backup brake system, the corresponding brake function is deactivated. The corresponding brake function is completely deactivated based on the severity of the defect before it is handed over to the backup brake system. Therefore, in the case of a defect affecting both brake systems, deactivation is performed more quickly.

[0016] The handover to the backup brake system, or the deactivation of the brake function, may give the driver the impression that the vehicle's deceleration during braking is temporarily reduced. However, this can be irritating to the driver, and this is precisely undesirable during the braking process. Therefore, in another preferred embodiment of the present invention, the driver is warned before the brake function is handed over to the backup brake system or before the corresponding brake function is deactivated. In this case, the warning can be issued audibly and / or visually, for example, by a display. This ensures that the driver is already warned before the braking operation and is not surprised by a change in brake behavior or the prevention of a particular driving operation.

[0017] In order to reduce the time required for classifying defects, the classification is carried out in particular by querying possible defects stored in a database. In this case, the database may be arranged in the control unit. Similarly, the database may be provided externally. This also includes databases that can only be accessed via a mobile connection with sufficient network speed. This database provides results matching defects of the corresponding brake device. This eliminates any potentially necessary prior simulation for the backup brake system, thereby accelerating classification.

[0018] In an advantageous development, defects are detected using electrical, mechanical, and / or hydraulic measurement values for detecting defects. For this purpose, sensors that transmit corresponding measurement values to the control unit are preferably arranged at specific positions. This makes it possible to more accurately localize and identify defects.

[0019] Before the handover to the backup brake system, it is advantageous that additional or already existing defects in the backup brake system are included in the classification. In this case, defects that have already been indicated before the occurrence of a defect that leads to a functional failure of the main brake system are understood as additional or already existing defects. This is particularly important in cases where an already existing defect would already lead to a functional failure of the backup brake system at the time of handover.

[0020] Therefore, advantageously, when the brake function is handed over, if an additional defect in the backup brake system relates to the corresponding brake function, the brake function is deactivated. This improves classification, thereby avoiding the handover of functions to the backup brake system.

[0021] In addition, a control unit is presented that is configured to implement such a method. In this case, the control unit monitors several braking functions, such as ABS, ESP, brake booster, ASR, other additional functions, and devices for detecting the driver's braking requests. [Brief explanation of the drawing]

[0022] [Figure 1] This is a diagram of the structure of a possible brake system with several possible defects. [Figure 2] This is a diagram illustrating an embodiment of a method for operating a brake device according to the present invention. [Modes for carrying out the invention]

[0023] Embodiments of the present invention are shown in the drawings and will be described in detail below.

[0024] Figure 1 shows a possible structure of the brake system 10 having several possible defects K and S. In this case, the brake system 10 comprises four wheel brakes 14 that can be braked via a hydraulic device 18. Furthermore, the brake system 10 comprises a first brake system 22, which here is the main brake system. In this case, the main brake system 22 comprises a main brake system control component I S The main brake system control component is hydraulically connected to the wheel brake 14 via the main brake system feed line connection 26 and the main brake system return line connection 30, thereby enabling the generation and adjustment of brake pressure.

[0025] In this embodiment, the main brake system 22 includes the main brake system control component I S The system further includes a main brake system control unit 32 located in the area. The main brake system control unit 32 can activate or deactivate the braking function of the main brake system 22.

[0026] The braking device 10 further comprises a second braking system 34 which here constitutes a backup braking system for the main braking system 22. Similar to the main braking system 22, the backup braking system 34 includes a backup braking system control component II having a corresponding backup braking system feed line connection 38 and a backup braking system return line connection 42. S The backup brake system control component is hydraulically connected to the wheel brake 14 via a backup brake system feed line connection and a backup brake system return line connection, thereby enabling the brake pressure for braking the wheel brake 14 to be generated and adjusted by the backup brake system 34.

[0027] Similar to the main brake system 22, the backup brake system 34 also has a backup brake system control component II in this embodiment. S The system has a backup brake system control unit 44 located in the area. The backup brake system control unit 44 is connected to the main brake system control unit 32 via a signal line 45, and the two control units 32 and 44 can communicate with each other via this signal line.

[0028] For powering the braking system 10, the vehicle is further equipped with an energy source 46, for example, a generator G or a DC-DC converter. The energy source 46 has an earth connection 50, through which the energy source 46 is connected to earth. The energy source 46 is further connected to an energy storage device 54 in the form of a battery that can be charged by the energy source 46, so that this battery can also take on part of the energy supply. Energy can be supplied via the energy source 46 and the battery 54 to several power-consuming devices 58 connected to the energy source 46 and the battery 54.

[0029] The main brake system 22 and the backup brake system 34 are similarly electrically connected to the battery 54 and the energy source 46, thereby enabling the supply of energy to the main brake system 22 and the backup brake system 34. The main brake system 22 further has a separate main brake system ground connection 62, through which the main brake system 22 is electrically connected to earth. Similarly, the backup brake system 34 is electrically connected to earth via a separate backup brake system ground connection 66.

[0030] In addition, Figure 1 shows several possible defects S and K as examples. In this case, these defects S and K are depicted in several locations within the brake device 10 and the electrical supply unit. In this case, defect K represents a defect relating to only one of the brake systems 22 and 34. Defect K relates to brake systems 22 and 34, for example, the direct electrical supply line to these brake systems 22 and 34, control component I S II S or located in the corresponding ground connection sections 62, 66.

[0031] In contrast, the defect S relates to the main brake system 22 and the backup brake system 34. In this case, these defects S may occur, for example, in the energy supply units 46 and 54 of the two brake systems 22 and 34, or in the hydraulic piping, immediately before the wheel brake 14. Therefore, when the corresponding braking function is transferred, the same defect S will occur in the backup brake system 34, and thus the improvement will not be achieved.

[0032] Corresponding braking functions of the brake systems 22, 34 can be activated or deactivated via the main brake system control unit 32 and the backup brake system control unit 44. For this purpose, a number of electrical, mechanical and / or hydraulic measurement values can be detected by the control units 32, 44, whereby defects can already be detected before a braking function fails.

[0033] Figure 2 shows an embodiment of a method for operating the brake device 10 according to the present invention. A first step A H , A B detects defects K, S in the braking functions of the main brake system 22 and the backup brake system 34, for example using measurement values. A second step B H , B B localizes the defects K, S within the brake device 10. This means, for example, that the position of the defects K, S or the corresponding defective component is detected using measurement values. Thereby, a third step C H , C B can classify these defects K, S, whereby the brake systems 22, 34 affected by these defects K, S can be detected.

[0034] In this case, the classification C of defects K, S H , C B may be detected independently by the respective control units 32, 44, or the control units 32, 44 may detect this based on the positioning of the defects K, S and measurement values stored in a database (not shown) in which a large number of defect values are stored. Time for classification C H , C B can be saved by querying the database. During classification C H , C B , additional defects K, S already existing in the brake device 10 can also be included.

[0035] Next, based on the classified defects K and S, the control units 32 and 44 check whether defects K and S relate only to the main brake system 22 or additionally to the backup brake system 34. During the check, it is confirmed whether these defects K and S continue to be related when the brake function is handed over. If the backup brake system 34 is not related to defects K and S, i.e., if it is defect "K", the brake function of the main brake system 22 is deactivated, and this brake function is taken over by the backup brake system 34 in the next step D1. However, before the brake function is handed over, a warning 74 can be issued indicating that the backup brake system 34 is about to take over the brake function.

[0036] However, if the inspection results indicate that defects K and S are related to both brake systems 22 and 34, i.e., if the defect is "S", then in the alternative step D2, the corresponding brake function is completely deactivated. However, prior to that, a corresponding warning 78 is issued indicating that the corresponding brake function is no longer available. Based on this information, certain driving operations can be restricted or completely blocked at the vehicle system level from that point onward.

[0037] By inspecting whether defects K and S are related to both brake systems 22 and 34 before handover, it is ensured that the failure of the backup brake system 34 is not only discovered after handover. This provides a time advantage in degradation, enhances safety, and avoids unnecessary handovers. [Explanation of Symbols]

[0038] 10 Brake system 14-wheel brakes 18. Hydraulic device 22 Main Brake System 26 Main brake system feed line connection 30 Main brake system return line connection 32 Main brake system control unit 34 Backup Brake System 38 Backup brake system feed line connection 42 Backup brake system return line connection 44 Backup Brake System Control Unit 46 Energy sources 50 Ground connection 54 Energy storage devices, batteries 58 Power consumption equipment 62 Main brake system ground connection 66 Backup brake system ground connection 74 Warning 78 Warning K, S defects II S Backup brake system control component I S Main brake system control component

Claims

1. A method for operating a vehicle brake system (10) comprising a main brake system (22), a backup brake system (34) capable of taking over the braking function of the main brake system (22), a main brake system control unit (32) capable of activating or deactivating the braking function of the main brake system (22), and a backup brake system control unit (44) connected to the main brake system control unit (32) and capable of activating or deactivating the braking function of the backup brake system (34), wherein the method is: - Detects a defect (K, S) in the brake function of the brake system (22, 34) (A Ｈ A Ｂ ) Steps and, - Identifying the defects (K, S) within the brake device (10) (B Ｈ , B Ｂ ) Steps and, - Classify the defects (K, S) relating to the corresponding brake function and the brake system (22, 34) (C Ｈ , C Ｂ ) Steps and, - A step (D1) of transferring the brake function detected as defective in the main brake system to the backup brake system (34) if the defect (K) is related only to the main brake system (22), thereby ensuring that the brake function remains operational by the backup brake system (34), If the measured parameter exceeds a threshold defined for this purpose, a defect is detected before the braking function of the brake system (22, 34) fails. method.

2. The method according to claim 1, characterized in that a defect is detected by a machine learning model trained to detect it before the brake function of the brake system (22, 34) fails.

3. The method according to claim 1, characterized in that if the defect (S) relates to the main brake system (22) and the backup brake system (34), the corresponding brake function is deactivated (D2).

4. The method according to claim 1, characterized in that a warning (74, 78) is issued to the driver before the brake function is handed over to the backup brake system (34) or before the corresponding brake function is deactivated.

5. The above classification (C Ｈ , C Ｂ The method according to claim 1, characterized in that the query is performed by querying from possible defects (K, S) stored in a database.

6. The method according to claim 1, characterized in that the defects (K, S) are detected using electrical, mechanical, and / or hydraulic measurements.

7. Before the handover (D1) to said backup brake system (34), additional or already existing defects (K, S) in said backup brake system (34) are included in said classification (C Ｈ , C Ｂ ), the method according to claim 1.

8. The method according to claim 1, characterized in that the brake function is deactivated if the additional defect (K, S) in the backup brake system (34) is related to the corresponding brake function at the time of the transfer of the brake function.

9. A control unit (32, 44) for a brake device (10) for carrying out the method described in claim 1.

10. The control unit (32, 44) according to claim 9, characterized by monitoring a brake function selected from a group of functions including ABS, ESP, brake booster, and ASR.

11. A computer program product comprising program code means for carrying out the method described in claim 1 when executed by the control unit (32, 44) described in claim 9.

12. A vehicle comprising the control unit (32, 44) according to claim 9 or 10.

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