WO2009115145A1

WO2009115145A1 - Method and device for controlling and compensating for failures of a brake actuator system of a decentralized electric brake system

Info

Publication number: WO2009115145A1
Application number: PCT/EP2008/066181
Authority: WO
Inventors: Stefan Strengert; Peter Blessing; Werner Harter
Original assignee: Robert Bosch Gmbh
Priority date: 2008-03-19
Filing date: 2008-11-26
Publication date: 2009-09-24
Also published as: DE102008000764A1

Abstract

The invention relates to a method for braking a motor vehicle, comprising a decentralized electric brake system having brake actuators, which are associated with the wheels of the motor vehicle and which, after a distribution of a total brake torque request M B_ges, independently of each other generate a portion of the requested total brake torque that is provided for by the distribution, wherein in the event of at least one faulty brake actuator said actuator generates no portion of the requested total brake torque, or restricts the portion generated. It is provided that the brake torque M B_Verlust of the faulty brake actuator missing from the requested total brake torque is at least partially or completely remedied by a redistribution of the total brake torque request M B_ges to the remaining functional brake actuator/brake actuators. Furthermore, the invention relates to a corresponding device.

Description

Method and device for controlling and compensating failures of a brake actuator of a decentralized electrical

braking system

The invention relates to a method for braking a motor vehicle with a decentralized electrical braking system having brake actuators associated with the wheels of the motor vehicle and independently generating a part of the requested braking torque provided by the distribution after distribution of a total braking torque requirement, in which case at least a faulty brake actuator this no or only partially generates its part of the requested braking torque.

State of the art

Decentralized electric brake systems - brake-by-wire systems - are brake systems in motor vehicles, in which there is no mechanical interaction between a control element and at least one brake actuator, but both the energy and the information transmission is purely electrical or electronic. Such systems have hitherto been implemented both in prototype vehicles and occasionally in production vehicles as electromechanical, electrohydraulic or self-boosting, mechatronic brake systems. A feature of such braking systems is that the braking effect on each wheel of a vehicle can be adjusted individually. In hydraulic or pneumatic braking systems, however, typically at least two brake actuators are interconnected and thus their respective braking effect. An error in such a brake system thus usually affects two brake actuators. Typically, the interconnection is chosen so that two brake actuators are located diagonally on the vehicle. On This is intended to reduce a resulting from the error of a Bremsaktuators imbalance of the braking forces acting on the vehicle sides and a resulting during braking yaw moment on the vehicle does not exceed an upper limit. The disadvantage here is that the achievable delay is reduced and thus the braking distance is extended. The previous strategy for a brake actuator failure in a brake-by-wire system is similar to the strategy used in hydraulic or pneumatic braking systems. In case of failure of a brake actuator of the brake actuator on the diagonally opposite side of the vehicle is also switched off and / or significantly limited in its braking effect, but in this case reduces the achievable delay and it extends the braking distance.

Disclosure of the invention

By virtue of the method according to the invention, it is provided that the braking torque of the faulty brake actuator which is missing for the requested total braking torque is at least partially or completely canceled out by redistributing the total braking torque requirement to the remaining functioning brake actuator / brake actuators. Such decentralized electric brake systems on electromechanical, electrohydraulic and / or self-reinforcing mechatronic basis - brake-by-wire systems - make it possible to distribute the requested total braking torque dynamically to the individual brake actuators. Thus, the total braking torque results from the sum of the braking torques applied by the individual brake actuators. The inventive method makes it possible to counteract a failure of one or more brake actuators in a brake-by-wire system and compensate for the effects on the vehicle behavior partially or completely. In particular, the significant extension of the braking distance, as in the prior art, is reduced.

In an advantageous embodiment, it is provided that the total braking torque requirement is predetermined by a driver and / or by a control unit. Typically, the Total braking torque request from a driver of the vehicle, for example, by pressing a brake pedal predetermined. Through the use of a control device, driver assistance systems can be used which modify the driver's total braking torque requirement in accordance with prescribed guidelines or specify completely independently of the driver.

According to a development of the invention, it is provided that the missing braking torque is determined by a desired-actual value comparison. A brake torque loss is determined by comparing detected brake torques - actual values - of individual brake actuators with a nominal brake torque distribution, which serve as setpoint.

According to a development of the invention it is provided that the redistribution of the total braking torque requirement on the basis of at least one braking torque potential of at least one functional

Brake actuator and / or based on the lack of braking torque. The braking torque potential describes the maximum additionally producible braking torque of a functioning brake actuator at the current time and thus a manipulated variable restriction. The knowledge of these wheel-individual braking torque reserves allows the redistribution of the required

Total braking torque taking into account the manipulated variable limitation and thus an optimal and realistic implementation of the braking torque requirement by the remaining, functioning brake actuators.

According to a development of the invention, it is provided that the

Braking torque potential is determined by means of a wheel speed, vehicle-specific parameters and / or a critical slip limit of the wheels. The determination of the braking torque potential exclusively from vehicle-specific parameters, such as the vehicle mass and the maximum brake pressure, can be optimized by taking into account as additional parameters the wheel speed and / or the critical slip limit. In this case, the critical slip limit is the limit at which a wheel changes from a roller into a sliding with respect to a road surface. The wheel speed can be taken into account, for example, in the way that too low a wheel speed compared to the actual Vehicle speed is also interpreted as a partial or complete sliding of the wheel relative to the road surface. Since a sliding of the wheels for safety reasons is undesirable, the consideration of the wheel speed and / or the critical slip limit of increased safety in a braking operation of the vehicle, which must be considered in particular reinforced if there is already a fault in a safety-related system such as the brake system , The knowledge of these wheel-individual braking torque reserves allows the redistribution of the required total braking torque and thus the optimal implementation of the total braking torque requirement, in particular under safety aspects, with the remaining, functioning brake actuators.

According to a development of the invention, it is provided that in the redistribution of the total braking torque requirement, a yaw moment about the vertical axis of the motor vehicle is at least partially or completely prevented. If a brake actuator fails on one side of the vehicle, there will be an asymmetry in the distribution of forces relative to the entire vehicle. Thus acts on the side of the motor vehicle on the brake actuators are fully functional, a higher force than on the side on the

Brake actuators are partially or not functional. This force imbalance produces a yawing moment for the entire vehicle, that is to say a torque which acts around a vertical axis of the motor vehicle. Thus, the motor vehicle is turned in such a braking operation to the side on which the brake actuators are still functional. In order not to surprise the driver with such a yaw moment and thus to provoke a spontaneous erroneous reaction of the driver, it is advantageous to prevent such yawing moments as completely as possible, but also only a partial prevention of yaw moment already represents a significant improvement from a safety point of view.

According to a development of the invention, it is provided that in the case of a yawing moment which is not completely prevented, the total braking torque requirement is initially reduced in order to allow the yawing moment to be slowed by the redistribution. It is advantageous if in the case of a not fully compensated yaw moment, the total braking torque requirement is first reduced to a level, as far as this is permissible from a safety point of view, in which the yaw moment can be fully compensated. Based on this reduced total braking torque, the required total braking torque is gradually built up, so as to maintain a stable, manageable state of the motor vehicle and to prevent a spontaneous erroneous reaction of the driver.

According to a development, it is provided that the method is used in a motor vehicle with an automated steering system, in particular an electric, hydraulic and / or pneumatic steering system, which adjusts a steering angle automatically according to the appropriate specification.

According to a development of the invention it is provided that the yaw moment is at least partially or completely offset by a steering intervention, in particular automatic steering intervention, the automated steering system. If such a steering system available, so it is advantageous, especially if a yaw moment by redistributing the

Total braking torque requirement can not be compensated to compensate for this by a steering intervention of the steering system. It is also conceivable to initially allow a strong yaw moment by asymmetries in the braking torque distribution at a required very strong delay, to compensate for this by a steering intervention, whereby the entire braking distance is considerably shortened.

Braking device with a decentralized electrical brake system, in particular for carrying out the previous method, wherein the brake system comprises a control device and brake actuators, which are associated with the wheels of the motor vehicle and independently distributed by the control device total braking torque request independently of one another provided by the distribution part of the requested total braking torque generate in the case of at least one faulty brake actuator that no or only a limited part of the requested total braking torque generated. It is provided that the control device has an overall brake torque redistribution device which at least partially or completely removes the brake torque of the faulty brake actuator that is missing for the requested total brake torque by redistributing the total brake torque requirement to the remaining active brake actuator / brake actuators.

According to a development of the invention it is provided that the braking device is associated with an automated steering system.

Brief description of the drawings

The drawings illustrate the invention by means of embodiments, in which:

Figure 1 shows a general course of a control method and

Compensation of failures of a brake actuator,

FIG. 2 shows a detailed course of the method in the event of a failure of a single brake actuator,

Figure 3 shows a detailed course of the method in case of failure of two

Brake actuators,

FIG. 4 shows a system topology variant for realizing the method,

FIG. 5 shows a further alternative system topology variant,

FIG. 6 shows a further alternative system topology variant,

FIG. 7 shows another alternative system topology variant and

FIG. 8 shows another alternative system topology variant. Embodiment (s) of the invention

1 shows a general procedure of the method 1 according to the invention for the control and compensation of failures of a brake actuator of a decentralized electrical brake system. The method 1 consists of four process steps 2, which proceed sequentially and will be described by means of the example of a decentralized electric brake system, not shown, with four brake actuators for four wheels of a motor vehicle. The individual wheels and the correspondingly assigned brake actuators are identified by their position with VL (front left), VR (front right), HL (rear left) and HR (rear right). In the first method step 2, a nominal distribution 3 of a total braking torque requirement Mß ges is performed. The total braking torque requirement M _B _ _g it is the nominal distribution 3 supplied via the arrow 7, which divides them into SoII- braking torques M _B _VL_SOII, M _B _VR_SOII, M _B _HL_SOII and M _B _HR_SOII the individual wheels. Those values are forwarded via an arrow 8 to an error detection 4. It also receives measured, actual actual braking torques Mβ VLjst, Mβ VRjst, M _B _HL_ιst and M _B _HR_ιst of the respective wheels via an arrow 9. The actual braking torques M _B _ _VL _ _ls t, M _B _ _VR _ _ls t, M _BH L _j st and M _B _ _H R_ _lst can alternatively be determined from other measured quantities or determined model-based. A failure of one or more brake actuators is by comparing the supplied desired braking torques M _BV L_SOII, M _BV R_SOII, M _B _HL_SOII and M _B _HR_SOII with the measured actual braking torques M _B _v _L _ _ls t, M _B _vR_ιst, M _B _HL_ιst and Mß HR _j st detected. On the basis of the detection, each wheel is assigned a status indication SVL, SVR, SHL and SHR, which identify the associated brake actuators either as faultless or faulty. The statuses S _VL , S _VR , S _HL and S _HR are forwarded via an arrow 10 to a third method step 2, a determination 5 of a brake torque loss M _B _veriust. If all the brake actuators are error-free in the third method step 2, then the method 1 can be terminated at this point or it can be started again for a cyclical execution. If, however, at least one faulty brake actuator i is detected, then a desired-actual-value comparison is carried out again, wherein the difference between the corresponding desired braking torque Mss _j soii and the actual braking torque M _B _ _us t is calculated at the faulty brake actuator i which is the missing braking torque M _B loss. The missing Bremsmonnent M _B _ve _r iust is passed through an arrow 10 to a fourth method step 2, which is a redistribution 6 of the total braking torque request M _B _ _g es. The redistribution 6 additionally be an arrow 12 the wheel speeds Π _V L, Π _V R, n _H ι_ and Π _H R and each individual wheel via an arrow 13 braking torque reserves M _B _vL_res, M _B _vR_ _res, M _{B HL} _ _r it and M _{B HR} _ _r fed it. Result of the redistribution 6 are adapted to each individual wheel target braking torques M * _B _ _V L_SOII, M * _B _ _V R_SOII, M * M * _B and _BH R_SOII _HL_SOII which are passed via an arrow 14 to the decentralized electric brake system.

FIG. 2 shows a detailed procedure of the redistribution 6 of the total braking torque requirement M _B _ _ges in the event that a single brake actuator i operates incorrectly. Hereinafter, relative terms i, k, I and m are used for wheels and their brake actuators, whereby the described method can be equally applied to all wheels VL, VR, HL and HR. In this case, the pair of wheels i and k and the pair of wheels I and m are each on one side of the vehicle, with the wheels i and I and the wheels k and m facing each other. The redistribution 6 is surrounded by a dashed line in FIG. Basically, the process image consists of three different elements, process steps 2, which are shown as rectangles, decision points (for example 15), which are shown diamond-shaped and arrows (for example 16), which mark the process between the process steps 2 and the decision points. For reasons of simplicity, not all method steps 2 are provided with reference symbols. As shown in Figure 1 in principle, the redistribution 6 via the arrow 16, the missing braking torque M _{B l} _veriust supplied to the wheel i with faulty brake actuator i. Furthermore, the wheel-specific braking torque reserves M _Bj _ _res , M _B _ _m _ _res , M _BJ _ _res M _{B k} _res are transferred to the redistribution 6 via the arrow 13. These serve as an upper limit (manipulated variable restriction) when changing wheel-specific SoII braking torques. In the process step 2 following the arrow 16, a braking torque increase 17 is made to wheel k. The increase takes place with a large gradient gradient in order to compensate for the missing braking torque M _{B l} _veriust quickly. This results in an increased setpoint braking torque M _{B k} _ _so iι on the wheel k. At decision point 15 it is checked whether a critical slip limit has been reached on the wheel k. The Calculation of the critical slip limit is based on the measured wheel speeds n ,, n _k , rii and n _m , which are supplied via the arrow 12. If the critical slip limit is not reached, an arrow 19 is used to go to a decision point 20, which checks whether the missing braking torque Mss _j lost on the wheel i has already been compensated. If this is the case, then an arrow 21 is used to switch to a final method step 22, in which new desired braking torques M ^* _B _ _k _soiι, M * BJ_ _SO II and M ^* B_m_soiι are determined, the new setpoint braking torque M ^* _Bj _soiι on the faulty brake actuator i is equal to zero. However, if the missing braking torque Mss _j missed at the decision point 20 is not fully compensated, then a new adjusted missing braking torque Mß i will be forwarded via the arrow 23 back to the method step 17. This process from decision point 18 to step 17 is cyclical until the missing braking torque M _Bj _veriust is fully compensated, or at the decision point 18, the critical slip on the wheel k is reached before the missing braking torque Mß _j veriust can be fully compensated. In this case, a remaining missing braking torque M _B _veriust_Re is transferred via the arrow 24 to the decision point 25. In the decision point 25 it is checked whether the remaining missing braking torque M _B _veriust_Re is above a predefined threshold M _Lιm . If this is the case, a method block 26 is used in the further course, otherwise the method block 27 is used. The process blocks 26 and 27 are each summarized by dash-dotted lines. In these process blocks 26 and 27, as a function of the remaining missing braking torque M _B _veriust_Re compared to the defined threshold M _Lιm an increase in the two desired braking torques MBJ SOII and M _B _m_soiι performed on the wheels I and m. The method block 26 begins with a method step 28 in which the desired braking torques MBJ SOII and M _B _m_soiι of the wheels I and m are increased. Since the threshold M _{Lmm was exceeded} in decision point 25 and thus a very high

Brake torque loss must be compensated, this increase is carried out with a small Gradient gradient, so as not to generate additional safety risks. Because in this process, block 26 applies, as the remaining missing braking moment M _B _veriust_Re is greater than the defined threshold M _Lιm, the compensation of the lack of braking torque M _BV can only eriust_Re be achieved by a highly asymmetric braking torque distribution with respect to the vehicle longitudinal axis. This asymmetric brake torque distribution leads to an undesirable yaw moment that acts on the entire vehicle. In order to give both the driver and vehicle control systems the opportunity to counteract this yawing moment by appropriate intervention, in such a case, the increase of the desired braking torques M _B _ι_soiι, M _B _m_soiι to the brake actuators of the wheels I and m with a gradient gradient performed, which does not exceed a maximum, which would cause an uncontrollable for the driver yaw moment. After increasing the desired braking torques, an arrow 29 is used to change to a decision point 30, which checks whether the critical slip on the wheel I has been reached. If this is the case, an arrow 31 is used to switch to a method step 2, in which an increase 32 of the setpoint braking torque M _B _ _m _soiι is carried out on the wheel m, wherein the gradient of increase is also kept small. Following this increase, an arbitration point 34 follows an arrow 33, which checks whether the critical slip at the wheel m has been reached. If this is the case, the method 1 can be completed via an arrow 35 and the associated concluding method step 22. At decision point 34 of the wheel critical slip on m is not reached, a further decision point 37 is used by an arrow 36, which checks whether the missing brake torque M _ßj v _er i i _ust is compensated on the wheel. If this is the case, the final method step 22 is initiated by an arrow 38. Is the lack of braking torque M _ßj v _er i _ust however, does not compensate for the wheel i, the method 1 is by means of the arrow 39 a

Method step 32 is returned, where it is cyclically continued until the final step 22 is initiated. If, on the other hand, it has been determined at decision point 30 that the critical slip on the wheel i has not been reached, then an arrow 40 is used to enter a decision point 41 which checks whether the critical slip at the wheel m has been reached. If this is the case, an arrow 42 leads to a method step 43, which increases the desired braking torque M _B J _SOII at the wheel I, this being done with a small _{gradient of gradients} . Subsequent to method step 43, method 1 leads via an arrow 44 to a decision point 45 which checks whether the critical slip on wheel I is reached. If this is the case, the final method step 22 is initiated via an arrow 46. If this is not the case, then an additional decision point 48 is used via an arrow 47, which checks whether the missing braking torque Mss _j lost on the wheel i has already been compensated. If this is the case, the final method step 22 is initiated via an arrow 49. If, however, the missing braking torque Mss _j lost on the wheel i is not compensated, then the method 1 is returned via an arrow 50 to the method step 43. If, at the decision point 41, the critical slip on the wheel m has not yet been reached, the method 1 is continued via an arrow 51 to a decision point 52, in which it is checked whether the missing braking torque Mβ _j lost on the wheel i has been compensated. If this is the case, the final method step 22 is initiated via an arrow 53. Otherwise, the method is returned to method step 28 via an arrow 54. Thus, the process block 26 is completed. The method block 27 is used when it is determined in the decision point 25 that the remaining missing braking torque M _B _veriust_Re is less than the defined threshold M _Lιm . The process block 27 is similar to the process block 26 with the difference that in the elevations 55, 56 and 57 of the corresponding desired braking torques not as in the corresponding process steps 2 of the process block 26 with a small

Rise gradients are performed, but they are performed with a large slope gradient to speed up Method 1 because there is little or no security risk.

FIG. 3 shows the method 1 in the event that two brake actuators are faulty. In the illustrated example, the brake actuators i and k are assumed to be faulty. In this case, the redistribution 6 of the total braking torque requirement M _B _ _g is shown in detail. The error detection 4 are supplied via the arrow 8, the current desired braking torques MB _J SOII, M _B _k_soiι, MBJ SOII and M _B _ _m _soiι. The malfunctions of the brake actuators are detected from these values and the actual braking torques Mβ _jj st, M _B _k_ _ls t, M _{j jj} st and M _B _m_ιst currently applied to the brake actuators, which are supplied via the arrow 9, as shown in FIG 1 and 2 has been described. Via the arrow 10, the status information S _VL , S _VR , S _HL and S _{HR of} the brake actuators to the determination 5 of the brake torque loss Mß veriust forwarded. This determines a lack of braking torque M _B _ι_ considered on a left side of the vehicle and a lack of braking torque M _BR on a right side of the vehicle in the direction of travel. Subsequently, these are summed to a total braking torque M _B _Versamtveriust and forwarded by means of an arrow 11 to a decision point 58 and thus to the redistribution 6 of the total braking torque request M _B _ _g it. The decision point 58 checks whether the two defective brake actuators i and k are arranged on a vehicle side with respect to the longitudinal axis of the vehicle. If this is the case, then the compensation of the missing braking torque M _BV can only be achieved by a strongly asymmetrical one

Braking torque distribution in relation to the vehicle longitudinal axis can be achieved. This asymmetric braking torque distribution leads to the undesirable yawing moment that acts around the vertical axis of the entire vehicle. Starting from the decision point 58, the missing braking torque M _{BV is} passed on via an arrow 59 to a first method block 60. This method block 60 is similar to the method block 26 of FIG. 2, wherein the decision points 61, 62 and 63 differ from the corresponding decision points of the method block 26 in such a way that in these decision points 61, 62 and 63 the missing total braking torque M _B _ _G is checked all over. If the defective brake actuators i and k are distributed on both sides of the vehicle, then starting from the decision point 58 via an arrow 64, a second method block 65 is followed up. This method block 65 is similar to the second method block 27 of FIG. 2. It contains decision points 58, 59 and 60, as does the method block 60. After successfully executing one of the method blocks 60 or 65, a final method step 66 is performed which addresses the remaining operational brake actuators I and m corresponding new desired braking torques M ^* _B _ι_ _SO ιι and M ^* _{B m} _ _SO ιι assigns, wherein the target braking torques to the faulty brake actuators M ^* _B _ι_soiι and M ^* _B _k_soiι are set to zero.

FIG. 4 shows a system topology variant 67 for implementing method 1 according to the invention. Method 1 is one

Brake system 68 superordinate vehicle dynamics control 69 assigned. The vehicle dynamics control 69 receives wheel speeds Π _VL , Π _VR , n _H ι_ and Π _HR one Raddrehzahlerfassung not shown, and may additionally relate information of another sensor, such as a steering angle detection, via an arrow 70. Furthermore, the brake system 68 transmits a total braking torque request M _B _ _g es generated by the driver and the status data S _VL , S _VR , Sm and S _HR to the vehicle dynamics control 69 via the data bus 71. The method 1 performs a redistribution 6 of the total braking torque requirement M _B _ _g es and sends the results MB I SOII, M _B _ k_soiι, MBJ SOII and M _B _m_soiι via the data bus 71 back to the brake system 68. This system topology 67 also allows the intervention in other vehicle systems, such as a steering system 73 via the data bus 71 or another, separate data bus. This improves the compensation of the missing braking torque M _B _veriust in the case of an unavoidable asymmetric distribution on different sides of the vehicle. In the event of a failure of the vehicle dynamics control 69, a rudimentary brake torque redistribution 74 according to the prior art is additionally provided within the brake system 68.

FIG. 5 shows a system topology variant 75 which is similar to the system topology variant 67 of FIG. 4, with the difference that the brake system 68 for the version of the wheel speeds Π _VL , Π _VR , n _H ι_ and Π _HR and their transmission to the vehicle dynamics control means 69 of the data bus 71 is used.

FIG. 6 shows a system topology variant 76 in which the method 1 according to the invention is applied by the brake system 68. For this purpose, the wheel speeds Π _VL , Π _VR , n _H ι_ and Π _HR must be transmitted from the vehicle dynamics control 69 by means of the data bus 71 to the brake system 68. A failure of the vehicle dynamics control 69 is to be secured in this system topology variant 76 in the brake system 68 by additional measures.

FIG. 7 shows a system topology variant 77 which is similar to the system topology variant 76 of FIG. 6, with the difference that in the system topology variant 77 the brake system 68 for detecting the wheel speeds Π _V L, Π _V R, n _H ι_ and Π _H R and their transmission to the vehicle dynamics control by means of the data bus 71 is responsible. A failure of Vehicle dynamics control 69 is not to be considered separately in such a Konfiguartion, whereas a failure of Raddrehzahlerfassung must be considered in a further Degratationsstrategie.

FIG. 8 shows a system topology variant 78, which represents an integrated solution approach. Both the vehicle dynamics control 69 and its additional sensor 70 are part of the braking system 68. Thus, the brake system 68 has all the information to include other vehicle systems, such as an electric steering system 73 to compensate for the impact of a brake actuator failure during a brake actuator failure.

Claims

claims

Anspruch [en] A method for braking a motor vehicle having a decentralized electrical brake system that has brake actuators associated with the wheels of the motor vehicle and which, after a distribution of a

Total braking torque request independently generate a part of the requested total braking torque provided by the distribution, wherein in the case of at least one faulty Bremsaktuators this or only partially generates its part of the requested total braking torque, characterized in that the requested total braking torque missing braking torque (M _B _veriust) of the faulty Brake actuator by redistributing the total braking torque requirement (M _B _ _g es) is at least partially or completely canceled on the one or more remaining functional brake actuator / brake actuators.

2. The method according to claim 1, characterized in that the total braking torque requirement (M _B _ _g es) is predetermined by a driver of the vehicle and / or by a control unit.

3. The method according to any one of the preceding claims, characterized in that the missing braking torque (M _B _veriust) is determined by a desired-actual value comparison.

4. The method according to any one of the preceding claims, characterized in that the redistribution of

Total braking torque request (M _B _ _ges ) on the basis of at least one braking torque potential (M _b _vL_res, M _B _vR_res, M _B _HL_res, M _B _ _H R_res) of at least one functional brake actuator and / or on the basis of the missing braking torque (M _BV eriust) takes place.

5. The method according to any one of the preceding claims, characterized in that the braking torque potential (M _B _vL_res, M _B _ _V R_res, M _B _HR_res, M _B _HL_res) by means of a wheel speed (n _V L, nvR, nHL, n _H R) . vehicle-specific parameters and / or a critical slip limit of the wheels is determined.

6. The method according to any one of the preceding claims, characterized in that in the redistribution of

Total braking torque request (M _B _ _g es) a yaw moment about the vertical axis of the motor vehicle is at least partially or completely prevented.

7. The method according to any one of the preceding claims, characterized in that at a yaw moment that is not completely prevented, the total braking torque requirement (M _B _ _g es) is first reduced in order to allow the yaw moment only slowly by the redistribution.

8. The method according to any one of the preceding claims, characterized in that it is used in a motor vehicle with an automated steering system, in particular an electric, hydraulic and / or pneumatic steering system, which automatically adjusts a steering angle according to the appropriate specification.

9. The method according to any one of the preceding claims, characterized in that the yaw moment is at least partially or completely offset by a steering intervention, in particular automatic steering intervention, the automated steering system.

10. Braking device with a decentralized electrical brake system, in particular for carrying out the previous method, wherein the brake system comprises a control device and brake actuators, which are assigned to the wheels of the motor vehicle and independently distributed by the control device total braking torque request independently provided by the distribution part of generate requested total braking torque, wherein in the case of at least one faulty brake actuator that generates no or only a limited part of the requested total braking torque, characterized in that the control device a Gesamtbremsmomentenneeuistrierungseinrichtung that at least partially or completely removes the brake torque (M _B _veriust) of the faulty brake actuator that is missing from the requested total brake torque by reallocating the total brake torque requirement (M _B _ _g es) to the remaining working brake actuator / brake actuators.

11. Braking device according to claim 10, characterized in that the braking device is associated with an automated steering system.