Procedure for safeguarding against a fault in an electric brake pedal

Abstract

Method for safeguarding against a fault in an electric brake pedal (5) of a vehicle (1) which has a braking system (2) and a drive (3) for moving the vehicle (1), wherein the vehicle (1) has an electric accelerator pedal (4) and an electric brake pedal (5), wherein the electric accelerator pedal (4) is used at least temporarily to control the drive power of the drive (3), wherein the electric brake pedal (5) is used at least temporarily to control the deceleration power of the braking system (2), wherein a control unit of the vehicle (1) performs fault monitoring of the electric brake pedal (5), wherein the method comprises the following steps: - Detecting a fault in the electric brake pedal (5) using fault monitoring (S10); - Deactivating the control of the braking system's deceleration power (2) using the electric brake pedal (5) (S11); - Providing control information that causes a change in the characteristic curve (KF) of the electric accelerator pedal (4) such that in a first characteristic curve area (KF1) of the electric accelerator pedal (4) control of the deceleration performance of the braking system (2) is possible, which was carried out before the detection of the fault by actuation of the electric brake pedal (5) (S12) characterized in that the first characteristic curve area (KF1) of the changed characteristic curve (KF) of the electric accelerator pedal (4), which immediately follows the zero position of the accelerator pedal (4), has a profile that is adapted to the profile of the characteristic curve (KB) of the electric brake pedal (4) before the detection of the fault at the electric brake pedal (4).

Description

[0001] The invention relates to a method for safeguarding against a fault in an electric brake pedal of a vehicle and a system for detecting the deceleration request of a vehicle.

[0002] Electro-hydraulic vehicle braking systems, which feature an electrically operated pressure generator and electrically actuated valves for implementing hydraulic braking processes, are generally known. So-called dry braking systems, which apply braking force to the wheel brakes without a hydraulic circuit, are also known.

[0003] Furthermore, it is known that the accelerator pedal and / or the brake pedal of a vehicle are designed as electric pedals. These have one or more sensors that detect the pedal position. This detected pedal position can then be translated by a control unit into an action for the braking system or the drivetrain.

[0004] Known electric brake pedals have three or more sensors that monitor the pedal position. If one of the sensors malfunctions, the other sensors can detect the fault. The electric brake pedal can then still be used, and the vehicle can continue to be operated, because the remaining at least two sensors provide redundancy in determining the pedal position.

[0005] The use of three or more sensors in the known electric brake pedals is disadvantageous because the hardware effort for multiple redundant safeguards is high, making such an electric brake pedal expensive.

[0006] It is known from DE 10 2019 215 422 A1 to provide two sensor signals for the brake pedal actuation, to validate these signals together and, if necessary, to perform a predefined braking maneuver.

[0007] From DE 10 2018 219 008 A1, a method for changing the characteristic curve of an accelerator pedal of a motor vehicle is known, wherein the method comprises the following steps: Determining that a brake booster of the motor vehicle has a malfunction, in particular that a brake booster of the motor vehicle is not working; and if a malfunction of the brake booster is determined, changing the characteristic curve of the accelerator pedal such that the motor vehicle is decelerated when the accelerator pedal and a brake pedal are not pressed.

[0008] Based on this, the object of the invention is to provide a method by which, despite limited redundancy of the brake pedal sensors, it is possible to continue operating the vehicle even if the electric brake pedal has a fault.

[0009] The problem is solved by a method with the features of independent claim 1. A system for detecting a vehicle's request to decelerate is the subject of dependent claim 15.

[0010] According to a first aspect, a method for safeguarding against a fault in the electric brake pedal of a vehicle with an electrically controlled braking system and a motor drive for propelling the vehicle is disclosed. The drive can, in particular, be an internal combustion engine or an electric motor. The vehicle has an electric accelerator pedal and an electric brake pedal. This means that there is no mechanical, but purely electrical, coupling between the electric accelerator pedal and the drive. Similarly, the electric brake pedal is coupled to the braking system purely electrically and not mechanically or hydraulically; that is, the transmission of the brake pedal position to the braking system is purely electrical, via the transmission of electrical information. The electric accelerator pedal is used, at least temporarily, to control the drive power.The braking system's deceleration performance is controlled, at least temporarily, by means of the electric brake pedal. A control unit, in particular a control unit of the vehicle's braking system, performs fault monitoring of the electric brake pedal to detect possible faults or defects. The procedure performs the following steps: The fault monitoring system first detects a fault in the electric brake pedal. The fault could, in particular, be due to a brake pedal sensor delivering no reading or an implausible reading.

[0011] If a fault is detected, the brake pedal is deactivated, meaning that the deceleration performance of the braking system can no longer be controlled via the electric brake pedal.

[0012] Finally, control information is provided, based on which the characteristic curve of the electric accelerator pedal is modified such that, within a certain initial range of the electric accelerator pedal's characteristic curve, the deceleration performance of the braking system can be controlled. This control occurs before the fault is detected by actuating the electric brake pedal. In other words, by modifying the characteristic curve of the electric accelerator pedal, both the functionality of the electric brake pedal and the functionality of the accelerator pedal can be implemented using the electric accelerator pedal. Deactivating the brake pedal and taking over its functionality via the accelerator pedal is subsequently referred to as pedal switching. The control information can be provided, for example, by a control unit of the braking system or by a higher-level control unit of the vehicle (so-called High Performance Computer, HPC).

[0013] The technical advantage of the proposed method is that the redundancy of the brake pedal sensor system can be reduced, since in the event of a brake pedal failure, the functionality of the brake pedal is transferred to the accelerator pedal, thus allowing the vehicle to remain operable, as the vehicle's braking system can be controlled via the modified characteristic curve of the accelerator pedal.

[0014] According to one embodiment, after changing the characteristic curve using the electric accelerator pedal, a deceleration performance of the vehicle can be achieved that is greater than the deceleration performance that was achievable using the electric accelerator pedal before the fault in the electric brake pedal was detected. Depending on the vehicle concept, a deceleration request can be implemented using the accelerator pedal even without a detected fault, i.e., before the brake pedal is deactivated, for example, in vehicles that implement a so-called one-pedal operating concept. In this vehicle concept, the recuperation property of an electric motor is often used to decelerate the vehicle by releasing the accelerator pedal.In contrast, the present disclosure enables the braking system to be actuated by means of the accelerator pedal by changing the accelerator pedal characteristic curve, so that the vehicle deceleration can be achieved with the accelerator pedal, which before the deactivation of the electric brake pedal was reserved exclusively for the electric brake pedal and not for the electric accelerator pedal.

[0015] According to the invention, the first characteristic curve segment of the modified characteristic curve of the electric accelerator pedal, which immediately follows the zero position of the accelerator pedal, has a profile that is adapted to the profile of the characteristic curve of the electric brake pedal before the detection of the fault in the electric brake pedal. The electric brake pedal can, for example, have a characteristic curve in which the pedal travel and the associated deceleration request exhibit a non-linear profile. This non-linear profile can, in particular, be such that the deceleration request, and thus the braking power effected by the braking system, increases disproportionately with increasing pedal travel. In this case, the characteristic curve of the electric accelerator pedal modified after the detection of a brake pedal fault can also exhibit a non-linear profile that corresponds, at least substantially or in form, to the non-linear profile of the characteristic curve of the electric brake pedal.Crucially, the characteristic curve of the electric accelerator pedal is inversely proportional to that of the electric brake pedal, such that the accelerator pedal's characteristic curve is steepest in the pedal's neutral position and the slope decreases with increasing pedal travel in the initial range. This provides the driver with a familiar braking performance curve across the pedal travel.

[0016] According to one embodiment, the modified characteristic curve of the electric accelerator pedal has a third characteristic curve range in which the drive power is controlled without actuation of the braking system. Between the first and third characteristic curve ranges, the modified characteristic curve of the electric accelerator pedal has a second characteristic curve range in which the curve has a less steep slope than in the first and third characteristic curve ranges. This second characteristic curve range separates a pedal position range in which the vehicle accelerates from a pedal position range in which the vehicle decelerates using the braking system and / or the vehicle's drivetrain.

[0017] According to one embodiment, the second characteristic curve section has a plateau, such that neither deceleration nor acceleration of the vehicle occurs within this section. This allows for comfortable vehicle control without a jerky transition between a pedal position range in which the vehicle accelerates and a pedal position range in which the vehicle decelerates.

[0018] According to one embodiment, if a fault in the electric brake pedal is detected during pedal actuation, the deceleration request detected by the electric brake pedal immediately before the fault detection is transferred to the characteristic curve of the electric accelerator pedal in such a way that the deceleration achieved by the electric accelerator pedal in its neutral position corresponds to this detected deceleration request when the signal is transferred to the electric accelerator pedal. Starting from this initial deceleration value, the characteristic curve of the electric accelerator pedal is modified over a period of time such that, after this period, the deceleration performance achievable in the neutral position of the accelerator pedal corresponds to the maximum achievable deceleration performance of the vehicle.This prevents a sudden change in braking power in the event of a fault in the electric brake pedal during braking. Without this switching, the vehicle would immediately brake hard, as the accelerator pedal is typically unpressed when the brake pedal is pressed, which, without a transition, would be equivalent to a full emergency stop.

[0019] According to one embodiment, when a fault in the electric brake pedal is detected while the brake pedal is not depressed and the electric accelerator pedal is being actuated, a gradual transition is implemented between a first characteristic curve of the electric accelerator pedal and a second characteristic curve of the electric accelerator pedal, by means of which the braking system is actuated depending on the pedal position. This allows the accelerator pedal characteristic curve to transition smoothly from a mode that does not actuate the braking system (i.e., the mode before the pedal switch) to a mode that does actuate the braking system (i.e., the mode after the pedal switch).

[0020] According to one embodiment, the duration of the transition between the first and second characteristic curves is influenced by the time gradient of the electric accelerator pedal's movement from an actuation point to its neutral position. If the driver holds the accelerator pedal at an actuation point and then immediately releases it so that it returns to the neutral position as quickly as possible, this—in contrast to a slow release of the accelerator pedal—often indicates that the driver intends to reduce the vehicle's speed by braking. To enable the driver to brake quickly when releasing the accelerator pedal rapidly, a faster transition between the first and second characteristic curves of the accelerator pedal is implemented when the time gradient of the accelerator pedal position is high, compared to when the time gradient is low.This allows the driver to react very quickly to dangerous situations after switching pedals by means of braking initiated by the accelerator pedal.

[0021] According to one embodiment, the duration of the transition between the first and second characteristic curves of the electric accelerator pedal is shortened when a vehicle assistance system detects an approaching object with which there is a risk of collision. This allows braking initiated by the accelerator pedal to be carried out very quickly after the pedal switchover in imminent collision situations.

[0022] According to one embodiment, if a fault in the electric brake pedal is detected while the vehicle is stationary, a message is displayed via a user interface indicating that the functionality of the electric brake pedal is being implemented by the electric accelerator pedal. The driver must then confirm this message via a user input in order to continue driving the vehicle. This ensures that, when the vehicle is not currently moving, the driver must first acknowledge that they are aware of the pedal switchover and thus the change in vehicle operation. This can increase the safety of the vehicle's passengers.

[0023] According to one embodiment, after changing the characteristic curve of the electric accelerator pedal, the vehicle can only be moved at a reduced speed. This, in turn, increases the safety of the vehicle's passengers.

[0024] According to one embodiment, if a fault in the electric brake pedal is detected, the driver is informed via a text-based message that, due to a defect in the brake pedal, the accelerator pedal's characteristic curve has been altered such that the electric accelerator pedal can also be used to control the vehicle's deceleration via the braking system. This informs the driver of the changed vehicle operation. Additional warnings may also be issued, such as audible and / or visual warnings in the form of warning lights.

[0025] According to one embodiment, the electric brake pedal has two sensors for detecting the pedal position. It should be noted that electric brake pedals are often designed with double redundancy and therefore have three or four sensors for detecting the pedal position. The method described above allows the vehicle to be braked using the accelerator pedal after switching the pedal position, so that a single redundant electric brake pedal with two sensors is sufficient.

[0026] According to one embodiment, fault detection is based on a comparison of the measured values ​​provided by the two sensors of the electric brake pedal. Preferably, a fault is inferred if the measured values ​​of the two sensors show a deviation greater than a predetermined deviation threshold.

[0027] According to a further aspect, a system for detecting a vehicle's desired deceleration is disclosed. The system includes a braking system and a drive for propelling the vehicle. It features an electric accelerator pedal and an electric brake pedal, the electric accelerator pedal being used, at least temporarily, to control the drive power. The electric brake pedal is used, at least temporarily, to control the braking system's deceleration power. A fault detection unit is provided, configured to detect faults in the electric brake pedal based on sensor information from the pedal.The system is configured to deactivate the control of the braking system's deceleration power via the electric brake pedal after detecting a fault in the electric brake pedal, and to change the characteristic curve of the electric accelerator pedal in such a way that in a first characteristic curve area of ​​the electric accelerator pedal, control of the braking system's deceleration power is possible, which was carried out by actuating the electric brake pedal before the fault was detected.

[0028] The term “characteristic curve of the electric accelerator pedal” within the meaning of the present disclosure is understood to be an assignment of acceleration and / or deceleration values ​​over the pedal travel of the accelerator pedal.

[0029] The term “characteristic curve of the electric brake pedal” within the meaning of the present disclosure refers to an assignment of deceleration values ​​over the pedal travel of the brake pedal.

[0030] The terms “approximately”, “essentially” or “about” mean, within the meaning of the invention, deviations from the respective exact value by + / - 10%, preferably by + / - 5% and / or deviations in the form of changes that are insignificant for the function.

[0031] Further developments, advantages, and possible applications of the invention will also become apparent from the following description of exemplary embodiments and from the figures. All features described and / or illustrated are, individually or in any combination, fundamentally the subject matter of the invention, irrespective of their compilation in the claims or their cross-reference. The content of the claims is also incorporated into the description.

[0032] The invention will be explained in more detail below with reference to exemplary embodiments shown in the figures. The figures show: Fig. 1. An example is a schematic representation of a vehicle; Fig. 2. An example is a schematic representation of an electro-hydraulic braking system with an electric accelerator pedal that has no hydraulic coupling with the braking system; Fig. 3. Exemplary and roughly schematically the characteristic curves of the electric brake pedal and the electric accelerator pedal before the pedal switching; Fig. 4. Exemplary and roughly schematic representation of the characteristic curves of the electric brake pedal and the electric accelerator pedal after pedal switching; Fig. 5. An exemplary and roughly schematic representation of a further embodiment of a characteristic curve of the electric accelerator pedal after pedal switching; and Fig. 6. An example block diagram illustrating the process steps of a procedure for operating a vehicle.

[0033] Fig. Figure 1 shows a roughly schematic representation of a vehicle 1, which has a drive 2 and an electro-hydraulic braking system 3. The drive 2 can be, for example, an internal combustion engine or an electric motor, by means of which a driving force can be applied to an axle of the vehicle 1. The electro-hydraulic braking system 3 has several wheel brakes 2.1, which provide braking power at the wheels of the vehicle 1, for example, by means of the frictional action of brake pads or brake shoes.

[0034] The drive and braking power of vehicle 1 is controlled without fault detection by means of an accelerator pedal 4 and a brake pedal 5. Both the accelerator pedal 4 and the brake pedal 5 are designed as electric pedals, i.e., the pedals have one or more sensors by which the pedal position can be detected. The measured values ​​provided by the sensors are transmitted to one or more control units of vehicle 1 in order to control the drive and braking power accordingly.

[0035] Fig. Figure 2 schematically shows an example of an electro-hydraulic braking system 2 of a vehicle 1. The braking system 2 comprises two independent braking circuits, each with an electric pressure generator 2.2, by means of which hydraulic pressure can be generated. The measured values ​​provided by the sensors 5.1 of the electric brake pedal 5 are converted by a control unit of the braking system 2 into control signals, which are transmitted to the hydraulic components of the braking system 2, in particular at least one pressure generator 2.2 and / or valves, in order to effect braking action at the wheel brakes 2.1.

[0036] The electric brake pedal 5 has two sensors 5.1 to redundantly detect its position. The vehicle 1 also has a fault detection unit F, which can detect a fault or malfunction of the electric brake pedal 5. The fault detection unit F is specifically designed to compare the measured values ​​provided by the two sensors 5.1. If the measured values ​​deviate above a predefined threshold, the fault detection unit F can detect a malfunction of the electric brake pedal 5.

[0037] In Fig. Figure 3 shows, by way of example, a characteristic curve KB of the electric brake pedal 5 and a characteristic curve KF of the electric accelerator pedal 4, assuming the electric brake pedal 5 is functioning correctly. The pedal travel is plotted on the x-axis in each case. For the characteristic curve KB of the electric brake pedal 5, the desired deceleration, as translated by the pedal travel, is plotted on the y-axis. For the characteristic curve KF of the electric accelerator pedal 4, the desired acceleration, as translated by the pedal travel, is plotted on the y-axis. In the illustrated embodiment, only the desired acceleration, i.e., no desired deceleration, is communicated via the accelerator pedal 4.It is understood that the characteristic curve KF of the accelerator pedal 4 may also have a different characteristic curve profile, such that in a first area of ​​the accelerator pedal travel, which follows the zero position of the accelerator pedal 4, a deceleration of the vehicle is also possible, in particular via the drive train, for example by recuperation of an electric motor of the vehicle 1 or by a corresponding control of the combustion engine of the vehicle 1.

[0038] If the fault detection unit F detects a defect or malfunction of the electric brake pedal 5, the brake pedal 5 is deactivated according to the invention, as shown by way of example in the left diagram of the Fig. As shown in Figure 4. Due to the detected fault of the brake pedal 5, no deceleration request is transmitted to the braking system 2 of the vehicle 1, regardless of the position of the brake pedal 5.

[0039] In order to avoid having to shut down vehicle 1 due to the detected fault of the brake pedal 5, the characteristic curve of the accelerator pedal 4 is changed, as shown, for example, in the right-hand diagram of the Fig. As shown in Figure 4. The comparison of the diagrams on the right between the Fig. 3 and Fig. As can be seen from the accelerator pedal 4, both the drive 3 and the braking system 2 of the vehicle 1 can now be controlled by means of the accelerator pedal 4. In an initial characteristic curve range, which immediately follows the zero position of the accelerator pedal 4, the driver can communicate a deceleration request via the accelerator pedal 4. It is understood that this deceleration request can be partially implemented by the drive 3 of the vehicle 1. However, the change in the characteristic curve KF of the accelerator pedal 4 results in the deceleration performance of the braking system 2, and thus of the wheel brakes 2.1 of the vehicle 1, being controlled, at least in a sub-range of the characteristic curve. This control was transmitted to the control unit of the braking system 2 by means of the brake pedal 5 before the detection of the fault in the electric brake pedal 5. Thus, by changing the characteristic curve of the accelerator pedal 4, it becomes possible to control the drive 3 and the braking system 2 with the accelerator pedal 4 alone.

[0040] Fig. Figure 5 shows a further embodiment of a modified characteristic curve KF of the electric accelerator pedal 4. The characteristic curve KF has three characteristic curve sections: the first characteristic curve section KF1, the second characteristic curve section KF2, and the third characteristic curve section KF3. The shape of the characteristic curve in the third characteristic curve section KF3 essentially corresponds to the shape of the characteristic curve before the detection of the fault in the brake pedal 5. In this third characteristic curve section KF3, an acceleration request is transmitted via the accelerator pedal 4; that is, the power of the drive 2 of the vehicle 1 is controlled.

[0041] The first characteristic curve section KF1 communicates a deceleration request from the driver via the accelerator pedal 4. The shape of the characteristic curve KF in the first characteristic curve section KF1 preferably corresponds essentially to the inverse shape of the characteristic curve KB of the brake pedal 5 before fault detection (see figure). Fig. (2 left diagram), where "inverse curve" is to be understood as meaning that after a fault detection of the brake pedal 5, positioning the accelerator pedal 4 in the zero position corresponds to a maximum pedal travel of the brake pedal 5 and thus to full braking. The curve of the characteristic KF in the first characteristic curve region KF1 is particularly non-linear, with the slope of the characteristic curve being greatest in the region of the zero position of the accelerator pedal 4 and decreasing with increasing pedal travel.

[0042] After fault detection of the brake pedal 5, the characteristic curve KF of the accelerator pedal 4 preferably has a second characteristic curve section KF2, which lies between the first and third characteristic curve sections KF1 and KF3. In this second characteristic curve section KF2, the characteristic curve KF exhibits a plateau, i.e., the slope of the characteristic curve KF in the second characteristic curve section KF2 is preferably zero or essentially zero. Thus, a change in the pedal position relating to the second characteristic curve section KF2 does not result in any acceleration or deceleration of the vehicle 1. This characteristic curve profile therefore achieves more comfortable vehicle control, as there is no immediate switch between acceleration and deceleration.

[0043] It should be noted that the characteristic curve values ​​of the characteristic curve KF of the accelerator pedal 4 do not have to be permanently assigned to a specific pedal travel or pedal position, but rather the characteristic curve KF can be adapted depending on the driving situation, i.e. in particular in such a way that different characteristic curve values ​​can be assigned to a specific pedal travel in different driving situations.

[0044] The following describes transition scenarios that enable the driver of vehicle 1 to make the transition from controlling vehicle 1 with the accelerator pedal 4 and the brake pedal 5 to controlling vehicle 1 exclusively via the accelerator pedal 4 in the event of a fault being detected in the area of ​​the brake pedal 5 as comfortable and safe as possible.

[0045] In the event that the fault of the electric brake pedal 5 is detected while the electric brake pedal 5 is being actuated, it is assumed that the accelerator pedal 4 is in its neutral position, i.e., completely released. This position of the accelerator pedal 4 would lead to very strong braking, in particular emergency braking of the vehicle 1, without any transition. To enable a smooth transition immediately after the fault detection of the electric brake pedal 5, the desired deceleration value determined immediately before the fault detection by the brake pedal 5 is preferably used as the starting value of the modified characteristic curve KF of the accelerator pedal 4. In particular, the modified characteristic curve KF of the accelerator pedal 4 is selected when the brake pedal 5 is deactivated such that the desired deceleration value determined immediately before the fault detection by the brake pedal 5 is implemented when the accelerator pedal 4 is in its neutral position.Subsequently, the characteristic curve KF of the accelerator pedal 4 is modified from this initial value such that the desired deceleration at the accelerator pedal 4's neutral position is successively increased. This means that the desired deceleration at the accelerator pedal 4's neutral position is increased over a certain period until a maximum deceleration value is reached at the accelerator pedal 4's neutral position. This allows the driver to switch from the brake pedal 5 to the accelerator pedal 4 without a sudden change in deceleration and then control the desired deceleration via the accelerator pedal 4.

[0046] In another driving situation, where the fault of the electric brake pedal 5 occurs not during the actuation of the brake pedal 5 but during the actuation of the accelerator pedal 4, a gradual transition between two characteristic curves of the electric accelerator pedal 4 is implemented during its actuation. In particular, the transition between the two characteristic curves of the electric accelerator pedal 4 can be designed such that, immediately after the detection of the fault of the brake pedal 5, deceleration of the vehicle 1 is initiated despite the pedal position remaining constant, and the deceleration is increased over a certain period of time at this pedal position, so that the driver of the vehicle 1 notices the change in the characteristic curve KF of the accelerator pedal 4, but this occurs without any significant loss of comfort.The driver can cancel this deceleration of the vehicle 1 by pressing the accelerator pedal 4 harder, thereby causing the vehicle 1 to continue moving at a constant speed or to accelerate the vehicle 1.

[0047] Advantageously, the duration of the time transition between a first characteristic curve KF of the accelerator pedal 4, which applies when the brake pedal 5 is functioning correctly, and a second characteristic curve, which is the target characteristic curve after the detection of a brake pedal 5 fault and applies after a certain time following this fault detection, depends on the time gradient of the movement of the electric accelerator pedal 4 from an actuation point that the accelerator pedal 4 occupies at the time of the brake pedal 5 fault detection to the zero position of the accelerator pedal 4. If the driver of the vehicle moves the accelerator pedal 4 immediately and quickly from the current actuation point to the zero position, i.e., the movement gradient of the accelerator pedal 4 is very large, it can be assumed that the driver wants to react quickly to a changed driving situation and possibly initiate a braking process.In this case, the duration of the time transition between the first and second characteristic curves of the accelerator pedal 4 is preferably shortened, so that the driver can initiate braking of the vehicle 1 using the braking system 2 very quickly by means of the accelerator pedal 4. Conversely, if the change in pedal position over time and thus the motion gradient of the accelerator pedal 4 is small, the duration of the time transition can be chosen to be longer in order to achieve the most comfortable change in the characteristic curve KF of the accelerator pedal 4.

[0048] Preferably, the vehicle 1 has a driver assistance system that uses data from the vehicle's sensors to detect hazardous situations, particularly collision situations. If the driver assistance system detects such a hazardous situation, particularly a collision situation, the transition between the first and second response curves of the electric accelerator pedal 4 can be shortened. This enables the driver to react promptly to the hazardous situation, even if the brake pedal 5 is deactivated, by initiating braking via the accelerator pedal 4 using the braking system 2.

[0049] If a fault in the electric brake pedal 5 is detected while the vehicle is stationary, a message can be displayed on the vehicle's user interface indicating that the functionality of the electric brake pedal 5 is now being taken over by the electric accelerator pedal 4 due to a defect. Additionally, the driver may be required to confirm this message via a user input in order to continue moving the vehicle 1.

[0050] Regardless of the driving situation in which the brake pedal 5 fault is detected, a message, in particular a text-based message, can be displayed on a user interface of the vehicle 1 indicating that the accelerator pedal's characteristic curve has been modified so that the electric accelerator pedal 4 can also be used to decelerate the vehicle 1 using the braking system 2. Additionally, the driver is preferably warned via warning lights or similar devices.

[0051] Advantageously, after deactivating the electric brake pedal 5 and changing the characteristic curve of the electric accelerator pedal 4, the maximum possible speed of the vehicle 1 is reduced. This ensures that the vehicle 1 remains movable, but reduces the risk posed by the vehicle 1 due to its control solely via the accelerator pedal 4.

[0052] Fig. Figure 6 shows a flowchart illustrating the process steps of a procedure for operating a vehicle.

[0053] First, a fault in the vehicle's electric brake pedal is detected using the fault monitoring unit (S10).

[0054] This fault detection leads to a deactivation of the control of the deceleration performance of the braking system by means of the electric brake pedal, i.e. the driver can no longer communicate a deceleration request by means of the brake pedal (S11).

[0055] Finally, control information is provided that modifies the characteristic curve of the electric accelerator pedal in such a way that in a first characteristic curve area of ​​the electric accelerator pedal, control of the deceleration performance of the braking system is possible, which took place before the detection of the fault by actuation of the electric brake pedal (S12).

[0056] The invention has been described above using exemplary embodiments. It is understood that numerous modifications and adaptations are possible without thereby departing from the scope of protection defined by the patent claims. Reference symbol list 1 vehicle 2. Braking system 2.1 Wheel brake 2.2 electric pressure generator 3 Drive 4 electric accelerator pedal 5 electric brake pedal 5.1 Sensor F Fault detection unit KB brake pedal characteristic curve KF characteristic curve accelerator pedal KF1 first characteristic curve area KF2 second characteristic curve area KF3 third characteristic curve range

Claims

[1] Method for safeguarding against a fault in an electric brake pedal (5) of a vehicle (1) which has a braking system (2) and a drive (3) for moving the vehicle (1), wherein the vehicle (1) has an electric accelerator pedal (4) and an electric brake pedal (5), wherein the electric accelerator pedal (4) controls the drive power of the drive (3) at least temporarily, wherein the electric brake pedal (5) controls the deceleration power of the braking system (2) at least temporarily, wherein a control unit of the vehicle (1) performs fault monitoring of the electric brake pedal (5), wherein the method comprises the following steps: - Detecting a fault in the electric brake pedal (5) using fault monitoring (S10); - Deactivating the control of the braking system's deceleration power (2) using the electric brake pedal (5) (S11); - Providing control information that causes a change in the characteristic curve (KF) of the electric accelerator pedal (4) such that in a first characteristic curve area (KF1) of the electric accelerator pedal (4) control of the deceleration performance of the braking system (2) is possible, which took place before the detection of the fault by actuation of the electric brake pedal (5) (S12) characterized by , that the first characteristic curve section (KF1) of the modified characteristic curve (KF) of the electric accelerator pedal (4), which immediately follows the zero position of the accelerator pedal (4), has a profile that is adapted to the profile of the characteristic curve (KB) of the electric brake pedal (4) before the detection of the fault on the electric brake pedal (4). [2] Method according to claim 1, characterized by, that after changing the characteristic curve (KF) by means of the electric accelerator pedal (4) a deceleration performance of the vehicle (1) can be achieved which is greater than the deceleration performance which could be achieved by means of the electric accelerator pedal (4) before the detection of the fault of the electric brake pedal (5). [3] Method according to claim 1 or 2, characterized by , that the modified characteristic curve (KF) of the electric accelerator pedal (4) has a third characteristic curve area (FK3) in which the drive power of the drive (3) is controlled without actuation of the brake system (2) and that the modified characteristic curve (KF) of the electric accelerator pedal (4) has a second characteristic curve area (KF2) between the first and third characteristic curve areas (KF1, KF3) in which the modified characteristic curve (KF) of the electric accelerator pedal (4) has a lower slope than in the first and third characteristic curve areas (KF1, KF3). [4] Method according to claim 3, characterized by, that the second characteristic curve area (KF2) has a plateau, such that in the second characteristic curve area (KF2) there is neither a deceleration nor an acceleration of the vehicle (1). [5] Method according to any one of the preceding claims, characterized by, that if a fault of the electric brake pedal (5) is detected during an actuation of the electric brake pedal (5), the deceleration request detected by the electric brake pedal (5) immediately before the fault detection is transferred to the characteristic curve of the electric accelerator pedal (4) in such a way that the deceleration achieved by the electric accelerator pedal (4) in the zero position at the time of transfer to the electric accelerator pedal (4) corresponds to this detected deceleration request and the characteristic curve (KF) of the electric accelerator pedal (4) is modified from this deceleration as a starting value over a period of time in such a way that after this period the deceleration performance achievable in the zero position of the accelerator pedal (4) corresponds to the maximum achievable deceleration performance of the vehicle (1). [6] Method according to any one of the preceding claims, characterized by, that when a fault of the electric brake pedal (5) is detected when the brake pedal (5) is not depressed and during the deactivation of the electric accelerator pedal (4), a time-sliding transition is realized between a first characteristic curve (KF) of the electric accelerator pedal (4) and a second characteristic curve (KF) of the electric accelerator pedal (4), by means of which the braking system (2) is actuated by the driver acting on the accelerator pedal (4). [7] Method according to claim 6, characterized by , that the duration of the temporal transition between the first and second characteristic curve is influenced by the temporal gradient of the movement of the electric accelerator pedal from an actuation point to the zero position of the accelerator pedal (4). [8] Method according to claim 6 or 7, characterized by, that the duration of the temporal transition between the first and second characteristic curve of the electric accelerator pedal (4) is shortened when an object approaching the vehicle (1) with which there is a risk of collision is detected by a driver assistance system of the vehicle (1). [9] Method according to any one of the preceding claims, characterized by , that if a fault of the electric brake pedal (5) is detected when the vehicle is stationary, a message is issued via a user interface indicating that the functionality of the electric brake pedal (5) is implemented by the electric accelerator pedal (4) and that the driver of the vehicle (1) must confirm this message by means of a user input in order to be able to continue moving the vehicle (1). [10] Method according to any one of the preceding claims, characterized by , that after changing the characteristic curve (KF) of the electric accelerator pedal (4) the vehicle (1) can only be moved at a reduced speed. [11] Method according to any one of the preceding claims, characterized by , that if a fault of the electric brake pedal (5) is detected, the driver of the vehicle (1) is informed via a text-based message that, due to a defect of the brake pedal (5), the characteristic curve of the accelerator pedal (4) has been changed in such a way that the electric accelerator pedal (4) can also be used to control the deceleration of the vehicle (1) by means of the braking system (2). [12] Method according to any one of the preceding claims, characterized by , that the electric brake pedal (5) has two sensors for detecting the pedal position. [13] Method according to claim 12, characterized by , that fault detection is based on a comparison of the measured values ​​provided by the two sensors of the electric brake pedal (5). [14] Computer program product which, when executed on a suitable computing unit, performs a procedure according to one of the above procedures. [15] System for detecting a deceleration request of a vehicle (1) which has a braking system (2) and a drive (3) for moving the vehicle (1), wherein the system has an electric accelerator pedal (4) and an electric brake pedal (5), wherein the electric accelerator pedal (4) is used at least temporarily to control the drive power of the drive (3), wherein the electric brake pedal (5) is used at least temporarily to control the deceleration power of the braking system (2), wherein a fault detection unit (F) is provided which is designed to detect a fault of the electric brake pedal (5) based on sensor information from the electric brake pedal (5), wherein the system is configured toAfter detecting a fault in the electric brake pedal (5), the control of the deceleration power of the braking system (2) by means of the electric brake pedal (5) is deactivated and the characteristic curve (KF) of the electric accelerator pedal (4) is changed in such a way that in a first characteristic curve area (KF1) of the electric accelerator pedal (4) control of the deceleration power of the braking system (2) is possible, which was carried out before the detection of the fault by actuation of the electric brake pedal (5), characterized by , that the first characteristic curve section (KF1) of the modified characteristic curve (KF) of the electric accelerator pedal (4), which immediately follows the zero position of the accelerator pedal (4), has a profile that is adapted to the profile of the characteristic curve (KB) of the electric brake pedal (4) before the detection of the fault on the electric brake pedal (4).

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