Braking system for a vehicle and method for operating such a braking system

Abstract

The present invention relates to a method for operating an electromechanical braking system (102) of a vehicle (100), wherein an additional reserve deceleration (508) of the braking system (102) is provided when a current deceleration capacity (504) of the vehicle (100) is less than a currently requested deceleration requirement (500).

Description

Field of the invention

[0001] The invention relates to a braking system for a vehicle and a method for operating such a braking system. State of the art

[0002] An electromechanical brake actuator can convert an electrical input signal into a braking force via an actuator and a gear. The intensity of the braking force can be adjusted by the strength of the input signal. If there is no electrical input signal, i.e., the actuator is de-energized, no braking force can be provided.

[0003] Therefore, an electromechanical brake actuator can have an energy storage device that is used to provide at least a portion of the braking force when de-energized. The energy storage device can, for example, be a preloaded spring that is released when the input signal fails. This allows a vehicle to be safely braked and brought to a stop even in the event of an electrical fault in the braking system. Disclosure of the invention

[0004] Against this background, the approach presented here provides a braking system and a method for operating a braking system of a vehicle according to the independent claims. Advantageous further developments and improvements of the approach presented here emerge from the description and are described in the dependent claims. Advantages of the invention

[0005] In a vehicle's fail-safe braking system, a reserve braking force is stored in an energy accumulator, such as at least one tensioned spring, and is released when an initial fault is detected in the braking system. The release, i.e. relaxation of the spring, can occur automatically, for example, if the braking system's power supply fails. The reserve braking force presses brake pads against friction surfaces, such as brake discs or drums, creating friction there. This friction generates a braking torque, which decelerates the moving vehicle to a standstill and safely holds the already stationary vehicle. A deceleration resulting from the braking force of a remaining intact partial braking system and the reserve braking force can, for example, be 6.5 m / s. 2For example, the braking system on the front axle may continue to function normally, while the braking system on the rear axle is defective and therefore reserve braking force is provided on the rear axle.

[0006] The deceleration provided by the intact partial braking system and the reserve braking force is greater than the majority of all decelerations that occur during normal vehicle operation. This braking force therefore decelerates the vehicle more than is usually requested by the driver or an assistance system. Furthermore, the reserve braking force cannot be regulated or deactivated. Once the reserve braking force is applied, the vehicle is permanently braked and can therefore no longer be driven normally.

[0007] In the approach presented here, the reserve braking force is only released when a residual deceleration of the braking system is less than a requested deceleration.

[0008] The approach presented here allows the vehicle to continue to operate without releasing the reserve braking force until, depending on the situation, the driver or the assistance system requests a greater deceleration than the braking system can provide after the initial fault.

[0009] According to a first aspect of the invention, a method for operating a braking system of a vehicle is presented, wherein an additional, in particular permanent, reserve deceleration of the braking system is provided when a current deceleration capacity of the vehicle is smaller than a currently requested deceleration requirement.

[0010] According to a second aspect of the invention, a braking system for a vehicle is presented, wherein the braking system is designed to carry out, implement and / or control the method according to the first aspect in corresponding devices, wherein the braking system has on a right wheel and a left wheel of at least one axle of the vehicle a reserve brake actuator, in particular an electromechanical one, which is designed to provide a reserve deceleration when a current deceleration capacity of the vehicle is less than a requested deceleration requirement.

[0011] Ideas for embodiments of the present invention may be considered, among other things, to be based on the thoughts and findings described below.

[0012] An electromechanical braking system of a vehicle can be designed without a hydraulic or mechanical connection between a brake control element and braking devices on the vehicle's wheels. In the electromechanical braking system, electromechanical brake actuators can be arranged on the wheels, which are controlled via electrical signals. The electrical signals can be used to request a desired deceleration or braking torque from the braking system.

[0013] The brake actuators can, for example, have a motor that converts a rotary motion of the motor into a motion axially aligned with the thread via a thread. This motion then acts on brake pads, which are pressed against friction surfaces to perform a braking operation, generating the braking torque through friction and decelerating the vehicle. A torque from the motor determines the value of the applied braking torque. When a deceleration request ends, the motor's rotation direction is reversed, and the brake pads are lifted off the friction surfaces, ending the braking operation.

[0014] The vehicle has a brake actuator, particularly an electromechanical one, on several wheels, in particular on all wheels. Each brake actuator can provide a maximum braking torque determined, for example, by the maximum torque of the engine. The sum of all available braking torques results in a braking capacity or deceleration capacity of the vehicle or the braking system.

[0015] If, for example, the motor of a brake actuator fails, this brake actuator can no longer provide its braking torque. Alternatively, the actuator's performance may be reduced (e.g., due to wear), which reduces the maximum braking torque at the wheel. The vehicle can only be braked with reduced deceleration capacity. The remaining deceleration capacity may be large enough to provide the requested deceleration in many situations. The deceleration request can be requested by a vehicle driver and / or a vehicle assistance system.

[0016] In at least two of the brake actuators, an energy accumulator can be arranged parallel to the threaded spindle. The energy accumulator can be designed as at least one spring arranged coaxially with the threaded spindle. The energy accumulator can be held in a tensioned state by an electromechanical locking mechanism. The locking mechanism can also be controlled by an electrical signal. The locking mechanism can be held in a locked position, for example, by an electromagnet.

[0017] When the energy accumulator is released by the locking mechanism, the brake pads are also pressed against the friction surfaces and the resulting braking torque initiates deceleration of the vehicle or the resulting friction prevents rotation of the wheel. The energy accumulator can therefore be part of a vehicle's parking brake, for example. In this case, only a portion of the force stored in the energy accumulator can be released, particularly for the parking brake. For example, the locking mechanism can hold two springs in a tensioned state in the locked position. When the parking brake is applied, the locking mechanism can be moved into a first unlocked position, for example through active actuation, which releases one of the springs and holds the vehicle while parked. When moving off, this spring can be tensioned again by the engine and transmission and then locked again by the locking mechanism.The first spring may be the weaker of the two springs.

[0018] The locking mechanism can release the second spring in a second unlocked position. The second unlocked position can, for example, be passively controlled by preventing the second unlocked position as long as the corresponding electrical signal is present. When the electrical signal drops, the locking mechanism can fall into the second unlocked position. The second spring can be used to store a reserve braking torque of the electromechanical brake actuator. The reserve braking torque can trigger a braking operation with a predefined minimum deceleration. This minimum deceleration allows the vehicle to be safely braked and brought to a standstill in the event of a brake actuator motor failure. The reserve braking torque can, for example, be provided to two brake actuators simultaneously. If the second spring has been triggered, a visit to the workshop may be necessary to re-tension the second spring.

[0019] Alternatively, a design solution could be to release the reserve braking torque through the first spring and also release the second spring for parking. This is particularly advantageous when only low reserve braking torques are desired, i.e., especially when the actuators are located on the rear axle.

[0020] In the approach presented here, the provision of the reserve braking torque is delayed until the reserve braking torque is additionally required to provide the requested braking torque.

[0021] The reserve braking torque or reserve deceleration can be provided after a fault in the braking system if the current braking capacity is less than the requested braking torque due to the fault. The approach presented can be used particularly after an initial fault in the braking system to increase vehicle availability. This allows, for example, a repair shop to be reached even after the initial fault.

[0022] The reserve braking torque or reserve deceleration can be provided symmetrically to the vehicle's longitudinal axis. The reserve braking torque or reserve deceleration can also be provided to the brake actuator opposite the fault. Symmetrical torque distribution can improve the vehicle's directional stability. In a braking system with X-brake circuits, the reserve braking torque or reserve deceleration can also be provided to the brake circuit not affected by the fault.

[0023] Alternatively, if the reserve brake actuators are not only controlled by the drive, the reserve braking torque can be provided individually for each wheel and the normal brake of the opposite wheel can be controlled in such a way that at least the same braking torque as the reserve braking torque is provided.

[0024] Reserve brake actuators in the braking system for releasing the reserve braking torque or reserve deceleration can be controlled by a control unit outside the braking system. The locking mechanism of the energy accumulator can be controlled by multiple actuators. In particular, switching to the second unlocked position can be performed by a dedicated reserve brake actuator. The reserve brake actuators can be controlled independently of the braking system. This means that an electronic fault in the braking system does not affect the ability to provide the reserve braking torque or reserve deceleration.

[0025] The reserve brake actuators can be controlled by a drive control unit of a vehicle's drive system. A drive system is generally independent of the braking system. In particular, the drive system can be an electric drive system. This means that signal lines from the drive system to the vehicle's wheels are already present, independent of the braking system. The reserve brake actuators can therefore be controlled via a parallel structure.

[0026] The reserve brake actuators can also be controlled by a brake control unit of the braking system. The reserve braking torque or reserve deceleration can be provided when the reserve braking torque or reserve deceleration is requested by the drive control unit and the brake control unit. A so-called AND circuit can be used to provide the reserve braking torque or reserve deceleration. This can prevent the energy accumulators from being triggered incorrectly.

[0027] At least one brake actuator of the electromechanical braking system can be controlled by the central brake control unit in particular to provide a force that prevents the reserve braking torque or reserve deceleration when the reserve braking torque or reserve deceleration is requested by the drive control unit but not by the brake control unit. The brake actuator can be operated in a direction opposite to the direction in which the braking torque is provided. The brake actuator can thus counteract the spring force of the energy accumulator to prevent the brake pads from pressing against the friction surface.

[0028] The reserve braking torque or reserve deceleration can be provided when the current deceleration capacity, composed of the current maximum control deceleration of the braking system and the currently available deceleration torque of a vehicle's drive system, is less than the deceleration requirement. An electric drive of the vehicle can provide a braking deceleration torque through recuperation. The deceleration torque can be added to the maximum possible braking torque of the braking system, i.e. its deceleration capacity, since it is rectified to the braking torque of the braking system. The deceleration torque can compensate for or even overcompensate for the failure of a brake actuator. If the deceleration torque is no longer available or cannot be provided in sufficient quantity, the reserve braking torque or reserve deceleration can be provided directly as a substitute.

[0029] The reserve brake actuators can be connected to a power supply independent of the braking system. The reserve brake actuators can have their own power supply. This ensures that the reserve brake actuators are not affected if the braking system experiences an electrical fault.

[0030] The reserve brake actuators can be powered by the vehicle's high-voltage system. A high-voltage system supplies power to the vehicle's drive system. The high-voltage system is designed for high voltages and high current flows. The high-voltage system operates at a vehicle high-voltage voltage of, for example, 1000 volts. A simple voltage converter can reduce the vehicle high-voltage voltage to the operating voltage of the reserve brake actuator. The power supply can also be activated only in the event of a fault to minimize electrical losses. In the event of a brake system failure, a small energy loss from the high-voltage system is acceptable. In the simplest case, the operating voltage can be provided by resistors connected in series.

[0031] A control unit for controlling the reserve brake actuators can have a power supply independent of the reserve brake actuators. Independent power supplies can achieve increased reliability.

[0032] It should be noted that some of the possible features and advantages of the invention are described herein with reference to different embodiments. A person skilled in the art will recognize that the features of the control device and the method can be combined, adapted, or interchanged as appropriate to achieve further embodiments of the invention. Short description of the drawings

[0033] Embodiments of the invention will now be described with reference to the accompanying drawings, wherein neither the drawings nor the description are to be construed as limiting the invention. Fig. 1 to 4 show representations of a vehicle with an electromechanical braking system according to an embodiment; and Fig. 5 shows an illustration of a braking process using a method according to an embodiment.

[0034] The figures are merely schematic and not to scale. Like reference numerals denote like or equivalent features. Embodiments of the invention

[0035] Fig. 1 shows a representation of a vehicle 100 with a braking system 102 according to one exemplary embodiment. The braking system 102 is, in particular, an electromechanical braking system 102. The vehicle has four wheels. An electromechanical brake actuator 104 of the braking system 102 is arranged on all wheels. One brake actuator 104 on a front wheel of the vehicle 100 and one brake actuator 104 on a diagonally opposite rear wheel of the vehicle are in a common brake circuit and are controlled by a common brake control unit 106. The brake circuits are therefore designed as X-brake circuits with separate brake control units 106. Two independent power supplies 108 supply all components of the braking system 102 with electrical energy.

[0036] The brake actuators 104 each have, for example, a motor and a gearbox. The gearbox converts a drive movement of the motor into a linear movement. The linear movement is transmitted to a wheel brake of the respective wheel. For example, a brake pad of a brake caliper is moved relative to the opposite brake pad of the brake caliper, and the brake pads are pressed against friction surfaces of a brake disc arranged between them. A drive torque of the motor then determines a resulting braking torque or a resulting deceleration at the wheel. Since the motor has a maximum drive torque, the wheel can be braked with a defined maximum braking torque or maximum deceleration.

[0037] The maximum braking torques or decelerations of all brakes of the braking system 102 add up to a maximum braking capacity or deceleration capacity of the braking system. By utilizing the maximum braking capacity or deceleration capacity, a maximum deceleration of 10 m / s can be achieved, for example. 2 can be achieved. However, the maximum braking capacity or deceleration capacity is only requested in extreme situations. In normal operation, the vehicle 100 is braked with significantly lower decelerations. Then, the brake control units 106 control the brake actuators 104 so that they jointly provide a requested braking torque or a requested deceleration requirement.

[0038] The braking system 102 has a reserve brake actuator 110 on each of the rear wheels' brake actuators 104. The reserve brake actuators 110 each have a preloaded energy accumulator, which is released or relaxed to provide a reserve braking torque or reserve deceleration to the rear wheels via its stored force. The reserve brake actuators 110 are controlled by a drive control unit 112 of a drive system of the vehicle 100. The drive control unit 112 is connected to one of the power supplies 108. The reserve brake actuators 110, together with a remaining functional part of the braking system 102, can provide a deceleration of 6.5 m / s. 2 The reserve braking torque or reserve deceleration is also greater than most of the braking torques required during normal operation. The reserve braking torque or reserve deceleration can be used to bring vehicle 100 to a standstill at any time.

[0039] When the energy accumulators are released, the reserve braking torque or reserve deceleration cannot be regulated or modulated. The reserve braking torque or reserve deceleration is always available at full power. When the vehicle 100 is stationary, the force of the energy accumulators still applied to the brakes can prevent the vehicle 100 from rolling away. Likewise, braking force for a parking brake can be provided by an additional energy accumulator.

[0040] If one of the brake actuators 104 of the braking system 102 has a fault which results in the brake actuator 104 no longer being able to provide its braking torque or deceleration, the approach presented here waits before activating the reserve brake actuators 110 until the requested braking torque or deceleration request is greater than or equal to the remaining braking capacity or deceleration capacity.

[0041] Fig. Figure 2 shows a representation of a vehicle 100 with a braking system 102 according to an embodiment. The vehicle 100 essentially corresponds to the vehicle in Fig. 1. Here, the drive control unit 112 for controlling the reserve brake actuators 110 is connected to both power supplies 108.

[0042] Fig. 3 shows a representation of a vehicle 100 with a braking system 102 according to an embodiment. The vehicle 100 essentially corresponds to the vehicle in Fig. 1. In contrast, the drive control unit 112 has its own power supply 108 for controlling the reserve brake actuators 110. This can, in particular, correspond to a high-voltage power supply.

[0043] Fig. Figure 4 shows a representation of a vehicle 100 with a braking system 102 according to an embodiment. The vehicle 100 essentially corresponds to the vehicle in Fig. 1. In contrast, the reserve brake actuators 110 are controlled here by the brake control units 106, whereby the reserve brake actuator 110 of the brake actuator 104 integrated in one brake circuit is controlled by the brake control unit 106 of the other brake circuit.

[0044] Fig. 5 shows a representation of a braking process using a method according to an embodiment. The braking process is carried out by a vehicle with a braking system as described, for example, in the Fig. 1 to 4. The braking or deceleration process is shown in a diagram with time t on its abscissa and a deceleration ax on its ordinate.

[0045] At the beginning of the braking process, a deceleration request 500 is requested. The braking system distributes the deceleration request 500 to the vehicle's brakes and provides a deceleration 502 corresponding to the deceleration request 500. The deceleration request 500 and thus also the set deceleration 502 are smaller than a maximum deceleration capacity 504 of the braking system.

[0046] Here, during the braking process, an error 506 occurs in at least one brake actuator of the braking system, causing the deceleration capacity 504 to decrease or fall. Even after the error 506, the deceleration capacity 504 is greater than the deceleration request 500. The braking system compensates for a brake force distribution or deceleration distribution among the remaining brake actuators and can continue to adjust the deceleration 502 to the deceleration request 500. This results in only a slight temporal deviation between the deceleration 502 and the deceleration request 500.

[0047] As the braking process continues, the deceleration request 500 increases again and exceeds the deceleration capacity 505. The moment the deceleration request 500 becomes greater than the deceleration capacity 504, the reserve brake actuators are activated and the reserve deceleration 508 is provided. The reserve deceleration 508 is added to the deceleration capacity 504. The braking system adjusts the deceleration distribution again and can thus adapt the deceleration 502 to the current deceleration request 500.

[0048] The deceleration request 500 then becomes briefly greater than the deceleration capacity 504 increased by the reserve deceleration 508. During this short time, the braking system cannot adjust the deceleration 502 according to the deceleration request 500.

[0049] After the deceleration request 500 is again smaller than the deceleration capacity 504, the braking system can again adjust the deceleration 502 to the deceleration request 500.

[0050] The deceleration request 500 drops to zero after the braking process. Since the reserve deceleration 508 is permanently applied after the provision, the deceleration 502 only drops to the reserve deceleration 508 after the braking process.

[0051] In the following, possible embodiments of the invention are summarized again or presented with slightly different wording.

[0052] An externally actuated default brake is presented.

[0053] Traditionally, braking systems are hydraulic. This gives the driver mechanical control over the brakes. Electromechanical brakes (EMBs) may become increasingly common in the future and replace hydraulic braking systems. In these systems, an electric motor is powered, the resulting torque is converted into translation by a gear, and a caliper with pads generates friction to decelerate the vehicle.

[0054] Such actuators can be designed so that, following a control or power supply failure, a defined, unchangeable default braking force is applied to the wheel, triggering a defined deceleration. In particular, these default actuators are also designed to enable a parking function. For example, at least one preloaded spring is held back by a latch actuated by a solenoid actuator. If the solenoid actuator is raised, for example, because the actuator's power supply is interrupted, the springs relax, activating the default braking.

[0055] EMB actuators can be attached to any or all of a vehicle's wheels, creating a system. A possible architecture or topology could consist of a central control unit, a communication bus, and the EMB actuators. The central control units handle brake force distribution and command the EMB actuators.

[0056] One challenge in the implementation of EMB systems is functional safety. While current hydraulic braking systems rely on hydraulic push-through as a backup in the event of an electronic failure, EMB systems are designed to be fail-operational. This provides redundancy within the system. In particular, three wheels can still be braked after a single wheel fails. This corresponds to a deceleration of approximately 6.4 m / s. 2 .

[0057] For this purpose, at least two EMB actuators can be redundantly supplied with power and controlled redundantly by the central control units. This involves a certain degree of system complexity and cost. Furthermore, redundant power supplies in particular pose a significant common cause (safety) risk. Since individual actuators are connected to both power supplies, these actuators are theoretically capable of destroying both power supplies by short-circuiting or grounding them.

[0058] Default actuators solve this problem by triggering a constant, defined braking action after the actuator error occurs, triggered by the actuator itself. Previously, the defined braking action was triggered immediately after the error occurred. The approach presented here significantly increases vehicle availability because the vehicle does not immediately brake constantly after such a fault, thus avoiding noise, heat, fading, odor, and particulate matter, making vehicle operation more comfortable and not automatically limiting its operating time.

[0059] In the approach presented here, the default braking process of an EMB actuator is not triggered by the same actuator, but rather externally. "External" can mean by a different brake circuit or by a different domain, e.g., the powertrain. Because the process is triggered externally, the default braking does not occur automatically as soon as a fault occurs, but only when the driving situation requires it, for example, because a high deceleration is required.

[0060] The advantage of the default actuators is that the required deceleration of 6.4 m / s 2 after an initial fault in the braking system, without the need for redundant control or power supply. The problem with conventional default actuators is that a constant, defined deceleration is activated immediately after a fault occurs. This deceleration is so high that the 6.4 m / s2 can be achieved with the residual braking system, although such high decelerations are only very rarely (approx. 1%) necessary.

[0061] Therefore, in the approach presented here, the default actuators are only activated (after the first error) when they are really needed, i.e. only in the case of very rare, very high delays. Fig.Figure 5 shows the temporal progression of a braking application. The error can occur during braking (as shown) or already exist at the beginning of braking, reducing the available deceleration. All braking maneuvers that require less deceleration than the available deceleration do not trigger a default braking maneuver. This can be a very large proportion of all braking applications (e.g., 75%), allowing the driver to continue driving the vehicle for a long time without negative impact. Only when a braking event occurs that exceeds the available deceleration (braking capability) is the default mechanism activated, triggering constant, irreversible braking.

[0062] In particular, the approach presented here inherently takes into account the current recuperation capability of the drive. If the drive can provide high deceleration, for example, because the battery is empty and warm, the available deceleration increases. Conditions are even conceivable in which the nominal braking capability of 10 m / s² can be reached after an initial fault without the default braking being activated. However, if the drive provides little or no recuperation / deceleration, the default mechanism is activated as soon as the driver request exceeds the braking capability.

[0063] The drive is traditionally not considered in safety concepts regarding braking because its recuperation capability is unreliable. This is explicitly not a problem here and is tolerated, as the default braking can be triggered at any time if the drive reduces its recuperation, which represents the "safe" state.

[0064] A specific architecture that is particularly advantageous is described below. The braking system is designed as an X-brake circuit. Each EMB actuator is controlled by a central control unit (VCU). The default parking brakes (PB) are located on the rear axle and are controlled by the powertrain (PT).

[0065] Thanks to the X-division, the drive system has a default brake in each brake circuit on the rear axle. This allows the default braking to be activated, if necessary, in the event of a failure of any brake circuit to provide deceleration. In particular, control by the PT can only be symmetrical (left and right), thereby reducing the safety impact (yaw) of an incorrect control. Furthermore, control can optionally be performed not by the powertrain, but by another EMB actuator, one of the two VCUs, or a third, not shown, control unit.

[0066] The actuator architecture of the default brakes can be designed as fail-active, so that the default braking is activated when the pawl is de-energized. Furthermore, a so-called AND connection can be implemented, so that both the powertrain control and the actuator itself must be de-energized to trigger the default braking. Alternatively, if the drive mistakenly triggers the default braking even though the actuator is functioning normally, the EMB actuator can constantly apply a return force to counteract the force of the springs and prevent the default braking.

[0067] In particular, the latch mechanism can be designed such that the actuator current / no current (without taking the powertrain into account) is sufficient to trigger at least one parking maneuver (parking after initial fault according to ECE R13H). This precaution can only be taken on one side. This side is powered by the other power supply, which does not power the external control unit that triggers the default braking (in this example, the PT control unit). This makes a parking maneuver possible after an initial fault in the power supply.

[0068] In summary, the approach presented here triggers a default braking action when the driver's request exceeds the current braking capability.

[0069] Finally, it should be noted that terms such as "comprising," "having," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Reference signs in the claims are not to be considered limiting.

Claims

[1] Method for operating a braking system (102) of a vehicle (100), wherein an additional reserve deceleration (508) of the braking system (102) is provided when a current deceleration capacity (504) of the vehicle (100) is less than a currently requested deceleration requirement (500). [2] Method according to claim 1, wherein the reserve deceleration (508) is provided after a fault (506) in the braking system (102) when the deceleration capacity (504) is less than the deceleration request (500) due to the fault (506). [3] Method according to one of the preceding claims, wherein the reserve deceleration (508) is provided symmetrically to a vehicle longitudinal axis of the vehicle (100). [4] Method according to one of the preceding claims, in which reserve brake actuators (110) of the braking system (102) are controlled by a control unit outside the braking system (102) to release the reserve deceleration (508). [5] Method according to claim 4, wherein the reserve brake actuators (110) are controlled by a drive control unit (112) of a drive system of the vehicle (100). [6] Method according to claim 5, wherein the reserve brake actuators (110) are further controlled by a brake control unit (106) of the brake system (102), wherein the reserve deceleration (508) is provided when the reserve deceleration (508) is requested by the drive control unit (112) and the brake control unit (106). [7] Method according to claim 6, wherein at least one brake actuator (104) of the electromechanical brake system (102) is controlled by the brake control unit (106) to provide a force preventing the reserve deceleration (508) when the reserve deceleration (508) is requested by the drive control unit (112) but not by the brake control unit (106). [8] Method according to one of the preceding claims, in which the reserve deceleration (508) is provided when the instantaneous deceleration capacity (504) composed of a currently maximum control deceleration of the braking system (102) and a currently available deceleration torque of a drive system of the vehicle (100) is less than the deceleration request (500). [9] Braking system (102) for a vehicle (100), wherein the braking system (102) is designed to carry out, implement and / or control the method according to one of the preceding claims in corresponding devices, wherein the braking system (102) has an electromechanical reserve brake actuator (110) on each of a right wheel and a left wheel of at least one axle of the vehicle (100), which is designed to provide a reserve deceleration (508) when a current deceleration capacity (504) of the vehicle (100) is less than a requested deceleration requirement (500). [10] Braking system (102) according to claim 9, wherein the reserve brake actuators (110) are connected to a power supply (108) independent of the braking system (102). [11] Brake system (102) according to claim 10, wherein the energy supply (108) of the reserve brake actuators (110) is via a high-voltage system of the vehicle (100). [12] Braking system (102) according to one of claims 9 to 10, wherein a control unit for controlling the reserve brake actuators (110) has a power supply (108) independent of the reserve brake actuators (110).

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