Electronic brake system for a motor vehicle, motor vehicle, and method for operating an electronic brake system

Abstract

The invention relates to a device of an electronic brake system (12) for a motor vehicle (10), comprising at least one first sensor (20, 22) for detecting a brake input on a brake pedal (14) of the motor vehicle (10), comprising at least one first electronic computer device (16) for generating a control signal (36) depending on the detected brake input, and comprising at least one brake device (28, 30, 32, 34) for actuating a brake depending on the generated control signal (36), characterized in that an additional electrical switching element (38) is provided, which generates an analogue control signal (40) for actuating the brake device (28, 30, 32, 34) in the event of a fault. The invention also relates to a motor vehicle (10), and to a method for operating an electronic brake system (12).

Description

[0001] 23-1759 PIF Electronic braking system for a motor vehicle, motor vehicle, and method for operating an electronic braking system. The invention relates to an electronic braking system for a motor vehicle, comprising at least one sensor for detecting a braking input at a brake pedal of the motor vehicle, at least one first electronic computing device for generating a control signal as a function of the detected braking input, and at least one braking device for actuating the brake as a function of the generated control signal. Furthermore, the invention relates to a motor vehicle with an electronic braking system and a method for operating an electronic braking system. Electronic braking systems are already known from the prior art. In particular, it is provided that, for example, a braking input to the brake pedal by a person is detected via a sensor.that the detected signal is transmitted to an electronic computing device, and a corresponding control signal for a braking device, in particular for a brake caliper, is transmitted electronically to the brake caliper. Based on this control signal, braking takes place. However, in order to ensure appropriate reliability, a redundant system is required in order to continue to perform a basic braking function, for example, for a so-called minimum-risk maneuver, in the event of a failure of such an electronic braking system. EP 2 964 499 relates to a brake actuation unit for a "break-by-wire motor vehicle brake system" with a brake pedal-actuated master brake cylinder. DE 10 2004 055 440 B4 relates to a motor vehicle braking system comprising a first master cylinder with a first piston,which moves according to a brake application by the driver. The object of the present invention is to provide an electronic braking system, a motor vehicle, and a method by means of which a simple redundant braking option is created for the motor vehicle. 23-1759 PIF This object is achieved by an electronic braking system, a motor vehicle, and a method according to the independent patent claims. Advantageous embodiments are specified in the subclaims. One aspect of the invention relates to an electronic braking system for a motor vehicle, comprising at least one first sensor for detecting a braking input at a brake pedal of the motor vehicle, at least one first electronic computing device for generating a control signal depending on the detected braking input, and at least one braking device for controlling a brake depending on the generated control signal. It is provided thatthat an additional switching element is provided which, in the event of a fault, generates an analog control signal to control the braking device. In particular, this provides a robust fallback level, should, for example, a fault occur within the electronic braking system. In particular, the analog control signal can thus control the braking device accordingly. The electronic braking system is, in particular, a so-called break-by-wire braking system. In this case, corresponding mechanical connections between the individual units are dispensed with. In particular, it is provided that, for example, the electronic computing device is designed to generate corresponding control signals depending on the braking input. Should, for example, an error occur within this communication, it is necessary,that a robust fallback level is created. This is provided in particular by the additional switching element. The switching element can in particular be a type of electrical switch, for example a potentiometer or other simple electronic components that can generate an analog control signal. The braking device is in turn controlled depending on the analog control signal. This allows, for example, basic braking functions to still be carried out on the basis of an analog control signal. In particular, a braking request can thus be provided via the brake pedal with greatly reduced technical effort and bypassing the first electronic computing device. This represents a robust function as an additional fallback level. In particular, the 23-1759 PIF mechanical fallback level is thus represented by simple electronic means,In particular, an analog switch such as the braking via the button of the electric parking brake. This is particularly evident in the prior art, for example, in the event of a failure of a main path via the electronic computing device, so that a safe minimum-risk maneuver can no longer be performed because the error robustness is no longer sufficiently ensured. According to the invention, it is now possible to move the motor vehicle with sufficient safety due to the additional, robust redundancy level. This provides, among other things, the possibility ofto park the motor vehicle in a safe position. In particular, the additional electrical switching element is thus provided in a type of bypass to the first electronic computing device. The bypass is unused during normal operation and is only used in the event of a fault. According to an advantageous embodiment, the braking device is controlled depending on a voltage drop in the analog control signal. In particular, it can thus be easily implemented that braking can be carried out via the analog voltage drop. Thus, there is no interruption of the voltage to the braking device, but merely the voltage drop serves to generate a corresponding analog control signal. Furthermore, it has proven advantageouswhen an electrical voltage for the electrical switching element is provided by the at least one braking device. The braking device is, in particular, a brake caliper. Each brake caliper, in turn, preferably has its own voltage source. Voltage can then be provided for the electrical switching element via the voltage source. Thus, an additional voltage source is not required, since the voltage is already provided by the braking devices. It has proven advantageous if a braking function is stored in the braking device, whereby the braking function is carried out when the braking device is controlled via the electrical switching element. In other words, it is provided that a braking signal is not generated directly via the analog control signal. A function is stored when the braking device receives the analog control signal,how braking is to be carried out. In particular, it can be provided, for example, that a predetermined deceleration torque is provided via the function. If the 23-1759 PIF analog control signal is now transmitted to the braking device, the deceleration is carried out according to the stored function. In this way, a basic braking function of the motor vehicle can be carried out in a simple yet robust manner. It has also proven advantageous if a braking effect of the braking device is set depending on the duration of the analog control signal. In particular, this can also be carried out via the stored braking function. For example, the intensity of the braking effect can be set depending on the duration. For example, the longer the analog control signal is present,the more intensively and strongly the motor vehicle is decelerated. Thus, a fallback level can be created in a simple manner. It has also proven advantageous if at least a second electronic computing device is provided, which is designed to control the braking device. In other words, for example, the electronic braking system has at least one second sensor, which is designed to detect a braking input at the brake pedal. The second electronic computing device is designed to generate a control signal depending on the detected braking input and to transmit it to the braking device. In particular, for example, the second electronic computing device already serves as a first fallback level for the first electronic computing device. The additional switching element is only controlled ifIf, for example, the first electronic computing device and the second electronic computing device have failed. In particular, if at least one error is recorded in the first main path via the first electronic computing device and a second error is recorded via the second main path via the second electronic computing device, the analog control signal is triggered. This can further increase safety. It should be noted at this point that the motor vehicle, in particular, can have at least four braking devices. As already mentioned, the braking devices are, in particular, brake calipers. In other words, each wheel of the motor vehicle has a corresponding separate and independent braking device.which can be controlled separately both via the main paths of the electronic computing devices and via the analog control signal. 23-1759 PIF In a further advantageous embodiment, it is provided that the braking device performs an emergency maneuver for the motor vehicle based on the analog control signal. In particular, the emergency maneuver can be designed with a basic braking function, for example, as a so-called minimum-risk maneuver. In other words, braking can be carried out via the braking device in such a way that, for example, the motor vehicle can be parked on the side of the road. This can increase road safety. It has also proven advantageous if the first electronic computing device is designed to monitor communication between the first sensor, the first electronic computing device, and the braking device.and a fault is detected as a function of this monitoring. Thus, faults within the electronic braking system can be monitored internally via the electronic computing device. In the event of a fault, the analog control signal can in turn generate a braking effect in the braking device. A further aspect of the invention relates to a motor vehicle with an electronic braking system according to the preceding aspect. Furthermore, the invention also relates to a method for operating an electronic braking system according to the preceding aspect. Communication is provided between at least the first sensor,the first electronic computing device and the braking device are monitored by the first electronic computing device. Upon detection of a fault by the first electronic computing device, an analog control signal for the braking device is generated by means of the additional electrical switching element. The method presented is, in particular, a computer-implemented method. Therefore, a further aspect of the invention relates to a computer program product with program code means which cause an electronic computing device, when the program code means are processed by the electronic computing device,to carry out a method according to the preceding aspect. Furthermore, the invention also relates to a computer-readable storage medium with at least one computer program product according to the preceding aspect. 23-1759 PIF Advantageous embodiments of the electronic braking system are to be regarded as advantageous embodiments of the motor vehicle and of the method. The electronic braking system and the motor vehicle have material features for this purpose in order to be able to carry out the method. A computing unit / electronic computing device can be understood in particular as a data processing device that contains a processing circuit. The computing unit can therefore in particular process data for carrying out computing operations. This may also include operations for indexed access to a data structure, for example a conversion table, LUT (look-up table).The computing unit may, in particular, contain one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), and / or one or more single-chip systems (SoCs). The computing unit may also contain one or more processors, for example one or more microprocessors, one or more central processing units (CPUs), one or more graphics processing units (GPUs), and / or one or more signal processors, in particular one or more digital signal processors (DSPs).The computing unit may also include a physical or virtual network of computers or other of the aforementioned units. In various embodiments, the computing unit includes one or more hardware and / or software interfaces and / or one or more memory units. A memory unit may be a volatile data memory, for example, a dynamic random access memory (DRAM) or a static random access memory (SRAM), or a non-volatile data memory, for example, a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory,EEPROM (23-1759 PIF "electrically erasable programmable read-only memory"), as flash memory or flash EEPROM, as ferroelectric random access memory (FRAM), as magnetoresistive random access memory (MRAM), or as phase-change random access memory (PCRAM). Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures, can be used not only in the respective combination specified,but also in other combinations. In particular, embodiments and combinations of features may also be encompassed by the invention that do not have all the features of an originally formulated claim. Furthermore, embodiments and combinations of features may be encompassed by the invention,which go beyond or deviate from the combinations of features set out in the dependent claims. The single figure shows a schematic block diagram according to an embodiment of a motor vehicle with an embodiment of an electronic braking system. The invention is explained in more detail below with reference to specific exemplary embodiments and associated schematic drawings. In the figures, identical or functionally equivalent elements may be provided with the same reference numerals. The description of identical or functionally equivalent elements is not necessarily repeated with respect to different figures. Fig. 1 shows a schematic block diagram of an embodiment of a motor vehicle 10 with an embodiment of an electronic braking system 12. The electronic braking system 12 has a brake pedal 14, in particular in the form of an electronic brake pedal,The electronic braking system 12 in the following exemplary embodiment further comprises a first electronic computing device 16 and a redundant second electronic computing device 18. The first electronic computing device 16 communicates with a first sensor 20 and with a first second sensor 22 on the brake pedal 14. 23-1759 PIF The second electronic computing device 18 communicates with a second sensor 24 and with a second sensor 26 on the brake pedal 14. Furthermore, four braking devices 28, 30, 32 and 34 are shown in particular. In particular, a first braking device 28,for example, for a front left wheel. Furthermore, a second braking device 30 is shown for a rear right wheel. Furthermore, a third braking device 32 is shown for a front right wheel. Furthermore, a fourth braking device 34 is shown for a rear left wheel. The first electronic computing device 26 and the second electronic computing device 18 communicate, in particular redundantly, with the braking devices 28, 30, 32, and 34. In particular, in the event of a failure of the main path via the first electronic computing device 16, the second electronic computing device 18 can again take over the braking of the motor vehicle 10. In particular, Fig. 1 shows that the first sensors 20,22 are designed to detect a braking input at the brake pedal 14. The first electronic computing device 16 is in turn designed to generate a control signal 36 as a function of the detected braking input and to transmit it to the braking device 28, 30, 32, 34 and thus to control the braking devices 28, 30, 32, 34. Fig. 1 further shows that according to the invention, an additional switching element 38 is provided which, in the event of a fault, generates an analog control signal 40 for controlling the braking devices 28, 30, 32, 34. In particular, it is provided that the braking device 28, 30, 32, 34 is controlled as a function of the voltage drop in the analog control signal 40. Furthermore, an electrical voltage for the electrical switching element 38 can be provided by the at least one braking device 28, 30, 32, 34. Furthermore, it can be provided that a braking function 42 is stored in the braking device 28, 30, 32, 34,wherein when the braking device 28, 30, 32, 34 is controlled via the electrical switching element 38, the braking function 42 is carried out. Furthermore, it can be provided that a braking effect of the braking devices 28, 30, 32, 34 is set as a function of a duration of the analog control signal 40. 23-1759 PIF Fig. 1 also shows that the second electronic computing device 18 can in turn generate a further control signal 44, which, for example, first transmits the further control signal 44 to the braking devices 28, 30, 32, 34 upon failure of the first electronic computing device 16. In particular, it can be provided that, on the basis of the analog control signal 40, the braking device 28, 30, 32,34 to perform an emergency maneuver of the motor vehicle 10. The electronic switching element 38 is provided, in particular, to implement a braking request via the brake pedal 14 with greatly reduced technical complexity, bypassing the two main paths via the first electronic computing device 16 and the second electronic computing device 18. This provides a robust function as an additional fallback level. In particular, the simulation of a mechanical fallback level can thereby perform braking using simple electronic means, such as the switching element 38 designed as an analog switch. According to the exemplary embodiment in Fig. 1, the background is that, for example, one of the two main paths or both main paths via the first electronic computing device 16 and the second electronic computing device 18 fails, which leads to the redundancy level and requires the fastest possible shutdown of the motor vehicle 10.because the second-fault robustness is no longer sufficiently ensured. The present invention allows the motor vehicle 10 to be moved with sufficient safety at the robust redundancy level. This, among other things, offers the possibility of parking the motor vehicle in a safe position.

[0002] -1759 PIF 10 List of reference symbols Motor vehicle Electronic braking system Brake pedal First electronic computing device Second electronic computing device First first sensor First second sensor Second first sensor Second second sensor First braking device Second braking device Third braking device Fourth braking device Control signal Electrical switching element Analogue control signal Braking function Further control signal

Claims

23-1759 PIF 11 Patent claims 1. Electronic braking system (12) for a motor vehicle (10), with at least one first sensor (20, 22) for detecting a braking input at a brake pedal (14) of the motor vehicle (10), with at least one first electronic computing device (16) for generating a control signal (36) as a function of the detected braking input and with at least one braking device (28, 30, 32, 34) for controlling a brake as a function of the generated control signal (36), characterized in that an additional electrical switching element (38) is provided which, in the event of a fault, generates an analog control signal (40) for controlling the braking device (28, 30, 32, 34).

2. Electronic braking system (12) according to claim 1, characterized in that the braking device (28, 30, 32, 34) is controlled as a function of a voltage drop in the analog control signal (40).Electronic braking system (12) according to claim 1 or 2, characterized in that an electrical voltage for the electrical switching element (38) is provided by the at least one braking device (28, 30, 32, 34).

4. Electronic braking system (12) according to one of the preceding claims, characterized in that a braking function (42) is stored in the braking device (28, 30, 32, 34), wherein the braking function (42) is carried out when the braking device (28, 30, 32, 34) is controlled via the electrical switching element (38).

5. Electronic braking system (12) according to claim 4, characterized in that. 23-1759 PIF 12, a braking effect of the braking device (28, 30, 32, 34) is adjusted as a function of a duration of the analog control signal (40). Electronic braking system (12) according to one of the preceding claims, characterized in that at least one second electronic computing device (18) is provided, which is designed to control the braking device (28, 30, 32, 34). Electronic braking system (12) according to one of the preceding claims, characterized in that, based on the analog control signal (40), the braking device (28, 30, 32, 34) performs an emergency maneuver for the motor vehicle (10).Electronic braking system (12) according to one of the preceding claims, characterized in that the first electronic computing device (16) is designed to monitor communication between the first sensor (20, 22), the first electronic computing device (16), and the braking device (28, 30, 32, 34), and a fault is detected as a function of this monitoring. Motor vehicle (10) with an electronic braking system (12) according to one of claims 1 to 8. 10.Method for operating an electronic braking system (12) according to one of claims 1 to 8, comprising the steps of: - monitoring communication between at least the first sensor (20, 22), the first electronic computing device (16) and the braking device (28, 30, 32, 34) by means of the first electronic computing device (16); and - upon detection of a fault by means of the first electronic computing device (16), generating an analog control signal (40) for the braking device (28, 30, 32, 34) by means of the additional electrical switching element (38).

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