Vehicle system with esc fault-tolerant brake system

Abstract

The invention relates to a vehicle system (100) for a vehicle (200), in particular a commercial vehicle (202), having an electronically controllable pneumatic brake system (101) and an electronically controllable steering device (103). The electronically controllable pneumatic brake system (101) has a redundant control unit (104) which, in the event of a failure of an electronic stability control (ESC1) of the brake system (101) during driving, controls the brake circuits (2, 4). In the event of a failure of the electronic stability control (ESC1) during driving, the redundant control unit (104) actuates the front axle (VA) with a front axle redundant brake pressure (pRVA) and / or the rear axle (HA) with a rear axle redundant brake pressure (pRHA) in terms of the axles, and the electronically controllable steering device (103) carries out a steering intervention for lateral stabilization for keeping the vehicle (200) within a tolerance corridor (TK) of a predetermined target trajectory (TSoll) of the vehicle (200). The invention also comprises a vehicle (200) and a method (300).

Description

TECHNICAL FIELD

[0001] The invention relates to a vehicle system for a vehicle, in particular a commercial vehicle.

[0002] In particular, such a vehicle system has an electronically controllable pneumatic brake system and an electronically controllable steering device, wherein the electronically controllable pneumatic brake system has at least one first brake circuit, at least one second brake circuit, a central control unit for controlling the first and second brake circuits and at least first and second front axle brake actuators for at least first and second front wheels on at least one front axle and at least first and second rear axle brake actuators for at least first and second rear wheels on at least one rear axle. The central control unit also has or is connected to an electronic stability control which is configured for wheel-specifically actuating the first and second front axle brake actuators and / or the first and second rear axle brake actuators. Furthermore, the electronically controllable pneumatic brake system also comprises a redundant control unit which, in the event of a failure of the electronic stability control during vehicle travel, controls the first brake circuit and / or the second brake circuit. The invention also relates to a method for decelerating and steering a vehicle, in particular a commercial vehicle, in particular having a vehicle system of the type mentioned at the outset, and to a vehicle, in particular a commercial vehicle, having a vehicle system of the type mentioned at the outset. BACKGROUND

[0003] In commercial vehicles, a pneumatic brake system is usually used which has two or more brake circuits. For example, a first brake circuit is provided for the front axle and a second brake circuit is provided for the rear axle. Alternatively, it is also conceivable to provide a first brake circuit for the left side of the vehicle and a second brake circuit for the right side of the vehicle. A cross connection can also be preferred. Furthermore, the electronically controllable pneumatic brake system can also have a third brake circuit which is provided, for example, for a parking brake device and / or for supplying a trailer.

[0004] In the context of the increasing automation of vehicles, in particular SAE class 3, 4 or 5 vehicles, it is necessary to make such brake systems safe even in the event of a fault, i.e. when one or more modules, electronic control units or other components fail. The known solutions for so-called FOBS (Fail Operational Brake Systems) are mainly aimed at residual availability in the event of a single fault in order to bring the vehicle into a safe state. The resulting residual performance often decreases significantly here. Electronic stability control is often no longer guaranteed.

[0005] For example, systems are known which, in the event of a failure of the central control unit, transfer the control to the electronic control unit of a further module, such as the electronic control unit of the front axle modulator or the rear axle modulator. There are also systems in which the electronic control unit of the parking brake module takes over the control of the brake system in the event of a failure in the central module. Furthermore, there are systems which build a purely pneumatic redundancy by means of a pressure transfer from one axle to the other in order to be able to regulate the redundant pressure at least pneumatically in this way.

[0006] Other solutions use systems which are built completely in parallel. In these systems, two brake systems are built in parallel and act on the respective brake actuators, for example, via shuttle valves. Although these systems are comprehensive and are able to reproduce most of the functions of the main brake system, they require a high assembly and wiring outlay and are therefore cost-intensive. SUMMARY

[0007] The task of the present application is to provide a brake system with high residual availability which can exert stable functions even in the event of a failure.

[0008] The application solves this task in a vehicle system of the type mentioned at the outset by the fact that, in the event of a failure of the electronic stability regulation during the vehicle travel, a redundant control unit actuates the front axle with at least a front axle redundant brake pressure and / or the rear axle with a rear axle redundant brake pressure by axle and an electronically controllable steering device carries out a steering intervention for lateral stabilization for keeping the vehicle within a tolerance band of a predetermined target trajectory of the vehicle.

[0009] The invention is based on the idea of providing a fault-tolerant brake system in such a way that, in a backup level, when the electronic stability control of the main system is no longer available, a regulating intervention for lateral stability is carried out via a combination of pressure actuation of at least one axle by axle and a superimposed steering intervention by an automated steering. A first brake circuit is preferably provided for the front axle and is connected to the first and second front axle brake actuators in order to supply them with brake pressure. A second brake circuit is preferably provided for the rear axle and is correspondingly connected to the first and second rear axle brake actuators in order to supply them with brake pressure. It is understood, however, that other configurations are also possible, for example, the first brake circuit can also be provided for a first brake actuator on the left front wheel and a second brake actuator on the right rear wheel, while the second brake circuit is provided for a second brake actuator on the right front wheel and a first brake actuator on the left rear wheel. Both the first and second brake circuits are controlled by a central control unit, which itself can receive brake commands from a higher-level unit, for example, in particular a unit for autonomous driving. The central control unit has an electronic stability control, which is able to carry out wheel-specific braking in specific braking situations. This means that the first and second front axle brake actuators and the first and second rear axle brake actuators are supplied with different brake pressures in order to thus be able to brake wheel-specifically in order to ensure the stability of the vehicle.

[0010] In the event of a failure of the electronic stability control, for example because the central control unit fails, because one or more wheel speed sensors on the wheels fail, or else because there is a fault which adversely affects the electronic stability control, the redundant control unit takes over control of the brake system, in particular of the first and second brake circuits. In the event of the redundant control unit taking over control, the redundant control unit drives at least one axle, i.e. the front axle and / or the rear axle, axle-specifically. This means that, on the at least one axle which is driven axle-specifically, the same brake pressure is provided to the respective brake actuator. For example, if only the front axle is driven axle-specifically, the redundant control unit causes the same brake pressure to be regulated on the first front axle brake actuator and the second front axle brake actuator, independently of the possibly different wheel speeds. Likewise, it is also possible for the rear axle to be driven axle-specifically, so that the same brake pressure is regulated on the first and second rear axle brake actuators. In the event of axle-specific driving, a front axle redundant brake pressure or a rear axle redundant brake pressure is regulated accordingly. If the vehicle also has a second front axle, this too can be driven axle-specifically, as can a second rear axle, an additional axle, etc. For example, if the vehicle has five axles, there are preferably a total of ten brake actuators, wherein each axle can be driven axle-specifically or the driving of the axles is combined into the driving of one or more axle groups. However, it is also possible within the scope of the application for only one axle to be driven axle-specifically, while for the other axles, for example by means of redundant wheel speed sensors and at least partially redundant electronic stability control, wheel-specific braking is still able to be implemented. However, at least one axle is driven axle-specifically within the scope of the application. In order to still ensure the stability of the vehicle, the electronically controllable steering device causes a steering intervention for lateral stabilization to be carried out in order thus to keep the vehicle within a tolerance band of a predetermined target trajectory of the vehicle. The wheel-specific braking on the axle driven axle-specifically is thus compensated for by means of the corresponding steering intervention via the electronically controllable steering device. In this way, the stability function is still able to be implemented in the brake system at all times, even when the electronic stability control of the primary system fails.

[0011] The target trajectory and the tolerance band for the target trajectory are preferably provided, for example via a vehicle bus, by a unit for autonomous driving. The target trajectory and the tolerance band for the target trajectory can be provided to the central control unit, the redundant control unit and / or the electronically controllable steering device or by means of the electronically controllable steering device. Preferably, all three modules receive the target trajectory and the tolerance band. When the electronic stability control of the primary system fails, the electronically controllable steering device carries out a steering intervention for lateral stabilization. It is also possible for the electronically controllable steering device to be additionally used during the functioning of the electronic stability control of the primary system in order to implement further functionalities.

[0012] In a first preferred embodiment, the electronically controllable steering device receives a steering wheel angle and / or a steering torque as a target value for a laterally stable steering intervention and adjusts the laterally stable steering intervention. For this purpose, the electronically controllable steering device is preferably connected to the electronically controllable pneumatic brake system, preferably to a redundant control unit, to an electronic stability control or to a redundant electronic stability control and / or to a unit for autonomous driving, and is configured to receive the steering wheel angle and / or the steering torque as a target value. The electronically controllable steering device is then preferably also set up to process it and to adjust it in coordination with the laterally stable steering intervention. The target value is preferably provided by the electronically controllable pneumatic brake system, preferably by the redundant control unit, by the electronic stability control or by the redundant electronic stability control.

[0013] The electronically controllable steering device is preferably connected to the central control unit for receiving an ESC signal of the electronic stability control or for receiving a signal derived or extracted from the ESC signal. Such a derived or processed signal can be, inter alia, an additional steering signal (e.g. steering wheel angle and / or steering torque). The electronically controllable steering device is preferably also connected to the redundant control unit in order to receive a redundant ESC signal or other signals from the redundant control unit, if necessary, or in order to provide the received ESC signal or a signal derived or processed from the ESC signal to the redundant control unit.

[0014] It is furthermore preferred that the vehicle system has a redundant electronic stability control which is connected to the redundant control unit and provides the redundant control unit with a redundant ESC signal. The redundant control unit preferably has a redundant electronic stability control. On the one hand, the redundant ESC signal can be used to drive the axles individually which are not driven by axle. On the other hand, the redundant ESC signal can also be used to adjust a laterally stable steering intervention by means of the electronically controllable steering device. For this purpose, the electronically controllable steering device can be configured to take the redundant ESC signal into account when adjusting the laterally stable steering intervention.

[0015] The electronically controllable steering device is therefore preferably connected to the redundant control unit or to the redundant electronic stability control in order to receive the redundant ESC signal.

[0016] Furthermore, it is preferred that the central control unit is connected to a first voltage source and the redundant control unit is connected to a second voltage source, which is independent of the first voltage source. According to this aspect, the central control unit and the redundant control unit are supplied by two separate, independent and uncorrelated voltage sources. For example, if the electronic stability control of the central control unit fails due to a malfunction of the first voltage source of the central control unit, according to this aspect it is ensured that the redundant control unit is still supplied with voltage. Thereby, the fail safety of the vehicle system is increased.

[0017] Preferably, the electronically controllable steering device or a part thereof is connected to the second voltage source. Preferably, the electronically controllable steering device is also connected to the first voltage source. This means that the electronically controllable steering device is supplied with voltage not only by the first voltage source but also by the second voltage source. It is thus possible that even when the first voltage source fails, the electronically controllable steering device continues to work with the second voltage source in order to thus adjust a laterally stable steering intervention.

[0018] According to a further preferred embodiment, the redundant control unit is connected to a first and / or second wheel speed sensor for receiving a wheel speed signal. Preferably, a first wheel speed sensor is arranged on the front axle and a second wheel speed sensor is arranged on the rear axle. In particular, a wheel speed sensor, i.e. a first and a second front axle wheel speed sensor, is arranged on each front wheel of the front axle, respectively. On the rear axle, a wheel speed sensor, i.e. a first and a second rear axle wheel speed sensor, is preferably arranged on each rear wheel, respectively. These wheel speed sensors provide a wheel speed signal, preferably to the redundant control unit, respectively. The first and the second wheel speed sensor preferably also provide a wheel speed signal to the central control unit and, if necessary, to further modules, for example in particular to a unit for autonomous driving. It is also preferred that these signals are provided via a vehicle bus.

[0019] Preferably, the vehicle system also has a parking brake circuit with a parking brake module connected to the central control unit and at least first and second spring-energized actuators at least on the rear axle or a further rear axle, wherein the redundant control unit forms or is integrated into the electronic control unit of the parking brake module. The parking brake module is preferably connected to a third compressed air reservoir and is part of a third brake circuit. The spring-energized actuators are preferably integrated into first and second rear axle brake actuators in order to form a so-called Tristop type brake actuator. According to this aspect, the redundant control unit is preferably integrated into or identical to the electronic control unit of the parking brake module. The parking brake module is preferably designed for taking over the control of the brake system in a redundant manner in the event that the central control unit does not work or works improperly. Thus, the parking brake module is preferably also connected to a unit for autonomous driving and to the central control unit and receives the same signals.

[0020] In a further preferred embodiment it is provided that, in the event of a failure of the electronic stability control, in the event of a wheel-specific regulation of a front axle redundancy brake pressure, the redundancy control unit supplies the front axle redundancy brake pressure to the first and second front axle brake actuators in order to brake the front axle wheel-specifically as a result. The same applies preferably to the rear axle. Thus, it is preferably provided that, in the event of a failure of the electronic stability control, in the event of a wheel-specific regulation of a rear axle redundancy brake pressure, the redundancy control unit supplies the rear axle redundancy brake pressure to the first and second rear axle brake actuators in order to brake the rear axle wheel-specifically as a result.

[0021] In a second aspect, the invention solves the task stated at the outset by a method for decelerating and steering a vehicle of the type stated at the outset, the method having the steps of: detecting a failure of an electronic stability control of an electronically controllable pneumatic brake system; in response to the detection of the failure: redundantly regulating, by means of a redundancy control unit of the electronically controllable pneumatic brake system, a redundancy front axle brake pressure to at least one front axle and / or a redundancy rear axle brake pressure to at least one rear axle, and carrying out a steering intervention for lateral stabilization by means of an electronically controllable steering device in order to keep the vehicle within a tolerance band of a predetermined target trajectory of the vehicle.

[0022] The redundancy rear axle brake pressure can be regulated by a parking brake module and other modules, such as a rear axle modulator. The redundancy rear axle brake pressure can be supplied to spring-loaded brake cylinders and service brake cylinders on the rear axle. Here, all combinations are conceivable and preferred.

[0023] It is to be understood that the vehicle system according to the first aspect of the invention and the method according to the second aspect of the invention have identical and analogous sub-aspects. In this respect, the preferred embodiments of the method according to the second aspect of the invention are also fully referred to the above description of the vehicle system according to the first aspect of the invention.

[0024] Preferably, the method further comprises the steps of: learning a front axle steering force on the front axle; learning a rear axle steering force on the rear axle; wherein the redundancy control unit increases the brake pressure regulation to the axle of which the higher of the front axle steering force and the rear axle steering force is learned. The steering force can be learned, for example, from a vehicle model. The steering force is a dynamic variable which is related to the side slip angle, the wheel load, the slip, the wheel camber and the friction value. The steering force is an output variable of the vehicle model which describes the dynamic vehicle state on the basis of different dynamic sensor data, such as lateral and longitudinal acceleration, yaw rate, steering angle, wheel rotational speed, vehicle speed, etc., and static variables, such as vehicle mass, center of gravity, wheel base, vehicle geometry, etc. Depending on which axle has the higher steering force, the regulated brake pressure is increased or the brake pressure to the axles is redistributed in favor of the axle with the higher steering force. This means, for example, that the redundancy control unit increases the front axle redundancy brake pressure if the steering force on the front axle is higher than the steering force on the rear axle.

[0025] In a further preferred embodiment, the method comprises the steps of: learning an oversteering of the vehicle; and in response: increasing the brake pressure regulation of the redundancy front axle brake pressure to the front axle and optionally also to the trailer; and steering with the electronically controllable steering device to the outside of the curve. Thereby, the oversteering is reduced and the vehicle is kept stably in the path even when the front axle redundancy brake pressure is regulated only to the front axle by axle. Steering with the electronically controllable steering device to the outside of the curve then forms a lateral stabilization steering intervention in the sense of the present application. Additionally or alternatively, the braking of the trailer can be used to achieve a segment braking.

[0026] Furthermore, the method preferably comprises the step of: learning an understeer of the vehicle; and in response: increasing the brake pressure regulation of the redundant rear axle brake pressure to the rear axle and optionally also to the trailer. In this embodiment, no electronically controllable steering intervention for lateral stabilization of the steering is required to get out of the understeer. Rather, in particular when the rear axle is driven in a vehicle axle-specific manner, the increase of the brake pressure regulation of the redundant rear axle brake pressure is sufficient. The vehicle is thereby decelerated and the understeer is reduced. It can be provided that the trailer possibly coupled to the vehicle is additionally braked. Thereby, in one variant, the speed of the vehicle together with the trailer can be quickly reduced. However, it is also conceivable that, in the case of an increase of the brake pressure regulation to the rear axle of the vehicle, the vehicle is intentionally allowed to slide slightly in order to further reduce the understeer. A further possible solution for reducing the understeer can be carried out in the following steps: setting a steering angle of approximately 0°; increasing the brake pressure regulation to the preferably all vehicle axles to a maximum value which preferably still allows a stable driving, i.e. preferably no or only a small amount of slip; both for a short time; and subsequently: setting the steering wheel angle such that the vehicle path is closer to the planned vehicle path. In this variant, the vehicle can be moved slightly to the outside of the curve, but the short and strong deceleration preferably brings the vehicle into a stable state, so that the vehicle is guided back onto the planned path by a corresponding steering intervention. The variants can also be combined. For example, even in the case of a simple increase of the brake pressure regulation to the rear axle, the steering angle can be reduced in order to bring the vehicle into a stable state.

[0027] In a third aspect, the task set out at the outset is solved by a vehicle, in particular a commercial vehicle, having a vehicle system according to the preferred embodiment of the vehicle system according to the first aspect of the application described above. Preferably, the vehicle system according to the first aspect of the application used in the vehicle according to the third aspect of the application is configured for implementing the method according to the second aspect of the application.

[0028] It is to be understood that the vehicle system according to the first aspect of the application, the method according to the second aspect of the application and the vehicle according to the third aspect of the application have the same and similar sub-aspects. In this respect, general reference is made to the above description for particular embodiments of the vehicle and further features and advantages. BRIEF DESCRIPTION OF DRAWINGS

[0029] Embodiments of the present application will now be described with reference to the accompanying drawings. These drawings do not necessarily show to scale the embodiments, but serve to illustrate the drawings in a schematic and / or slightly distorted form. For further details reference is made to the relevant prior art identified in the drawings. It is considered that in the embodiments forms and details can be modified or changed in relation to each other without departing from the general idea of the present application. The features of the present application disclosed in the description and drawings, whether individually or in any combination, are important to the invention. In addition, all combinations of at least two of the features disclosed in the description and / or drawings are within the scope of the present application. The general idea of the present application is not restricted to the exact form or details of the preferred embodiments shown and described below. Values within the limits mentioned are to be disclosed and can be used arbitrarily and are protected by the patent. For the sake of simplicity, the same reference signs are used below for identical or similar parts or parts having the same or similar function.

[0030] Further advantages, features and details of the present application are known from the following description of the preferred embodiments and in connection with the drawings; in which:

[0031] Figure 1 A schematic system layout of the present application is shown;

[0032] Figure 2 A vehicle with a vehicle system according to the present application is shown;

[0033] Figure 3 A vehicle with a vehicle system of a second embodiment is shown;

[0034] Figure 4 A vehicle driving on a curve is shown; and

[0035] Figure 5 A schematic flow of a method is shown. DETAILED DESCRIPTION

[0036] Figure 1 First the general structure of the vehicle system 100 is illustrated in a block diagram. The vehicle system 100 comprises a central control unit 102 which is arranged to control an electronically controllable pneumatic brake system 101 (see Figure 2 and Figure 3 ). The central control unit 102 receives a target trajectory TSoll from a target trajectory control 110. The target trajectory control 110 can for example be part of a unit 112 for autonomous driving (see Figure 2 and Figure 3), but can also be provided separately inside the vehicle 200. It is furthermore possible that the target trajectory control 110 is provided in a cloud service, or supplies data via such a cloud service, on the basis of which the target trajectory TSoll is then generated. The vehicle system 100 also comprises an electronically controllable steering device 103. The electronically controllable steering device 103 also receives the target trajectory TSoll from the target trajectory control 110. The electronically controllable steering device 103 is provided for steering the vehicle 200 and can act on one or more axles.

[0037] Within the scope of the application, a redundant control unit 104 is also provided, which takes over the control of the brake system 101 in the event of a failure and / or no longer normal operation of the electronic stability control ESC1 (see Figure 2 and Figure 3 ) of the central control unit 102. The redundant control unit 104 thus comprises or controls a secondary front axle brake control 114, a secondary rear axle brake control 116 and optionally a secondary trailer brake control 118. The secondary trailer brake control 118 is only provided if the vehicle 200 is equipped for towing a trailer 204 (see Figure 2 ). Otherwise, this secondary trailer brake control can be omitted. The central control unit 102 accordingly comprises a primary front axle brake control, a primary rear axle brake control and a primary trailer brake control, which are known per se. They are not shown in detail in Figure 1 .

[0038] Optionally, a redundant electronic stability control ESC2 is also provided, which is connected to the redundant control unit 104 here. The redundant electronic stability control ESC2 can provide a redundant ESC signal SER to the redundant control unit 104, which will be described in detail later. The redundant control unit 104 is also connected to the electronically controllable steering device 103 and provides a redundant brake signal SBR to this, which the redundant control unit 104 preferably also provides to the respective further modules in the brake system 101 for braking a specific axle.

[0039] The redundancy control unit 104 is set up to drive at least one axle, in particular the front axle VA and the rear axle HA, in an axle-specific manner in the event of a redundancy, i.e. when the redundancy control unit 104 takes over control of the brake system 101. In the event of an axle-specific driving of the axles VA, HA, identical brake pressures are regulated to the respective brake actuators of the axle VA, HA. Then, wheel-specific braking no longer takes place on the axle. For this reason, the redundancy control unit 104 is connected to the electronically controllable steering device 103, which in this case carries out a lateral stabilization steering intervention for keeping the vehicle 200 within a tolerance band TK of a predetermined target trajectory TSoll (see Figure 4 ). Thus, during normal operation, the central control unit 102 can control the brake system 101 independently and allow wheel-specific braking, whereas in the event of a redundancy, the redundancy control unit 104 and the electronically controllable steering device 103 act together in order to keep the vehicle 200 on the target trajectory TSoll.

[0040] In addition to the target trajectory TSoll, the electronically controllable steering system 103 can also receive and regulate a steering wheel angle LW and a steering torque LM as target values WSoll for the lateral stabilization steering intervention.

[0041] Now that the basic concept of the vehicle system 100 has been described, Figure 2 and Figure 3 two specific embodiments of the vehicle system 100 in a vehicle 200, in particular in a commercial vehicle 202, are shown. The commercial vehicle 202 comprises an electronically controllable pneumatic brake system 101 as described above in the basic description. The electronically controllable pneumatic brake system has a first brake circuit 2, which here is in the form of a front axle brake circuit for the front axle VA, and a second brake circuit 4, which here is in the form of a rear axle brake circuit for the rear axle HA. The first brake circuit 2 is supplied by a first compressed air reservoir 20. The first compressed air reservoir 20 provides a reservoir pressure pV. Furthermore, a first and a second front axle brake actuator 3a, 3b are provided on the front axle VA, wherein the first front axle brake actuator 3a is provided for a first front wheel, here the right front wheel 5a, and the second front axle brake actuator 3b is provided for a second front wheel, here the left front wheel 5b. In this embodiment (see Figure 2 ), the first brake circuit 2 provides a front axle brake pressure pBVA in a wheel-specific manner, more precisely a first front axle brake pressure pBVA1 to the first front axle brake actuator 3a and a second front axle brake pressure pBVA2 to the second front axle brake actuator 3b.

[0042] A second brake circuit 4, here the rear axle brake circuit, is supplied by a second compressed-air reservoir 22, which also provides the reserve pressure pV. On the rear axle HA, first and second rear axle brake actuators 8a, 8b are provided, which are actuated by means of the second brake circuit 4. The first rear axle brake actuator 8a is provided for the first rear wheel 5c, and the second rear axle brake actuator 8b is provided for the second rear wheel 5d. The second brake circuit 4 provides the first rear axle brake actuator 8a with a first rear axle brake pressure pBHA1 and the second rear axle brake actuator 8b with a second rear axle brake pressure pBHA2 in a wheel-specific manner. By virtue of the wheel-specific regulation of the brake pressures pBVA1, pBVA2, pBHA1 and pBHA2, the vehicle 200 is kept on a target trajectory TSoll, which is provided by the target trajectory control 110 of the central control unit 102.

[0043] In the embodiment shown, the brake system 101 also comprises a parking brake circuit 10, which is supplied by a third compressed-air reservoir 24. The third compressed-air reservoir 24 also provides the reserve pressure pV. The parking brake circuit 10 has a parking brake module 11, which receives the reserve pressure pV from the third compressed-air reservoir 24. The parking brake circuit 10 also has first and second spring-energized actuators 12a, 12b on the rear axle HA of the vehicle 200. The first spring-energized actuator 12a is provided for the first rear wheel 5c, and the second spring- energized actuator 12b is provided for the second rear wheel 5d. Figure 2 In the embodiment shown, the first and second spring-energized actuators 12a, 12b are integrated with the first and second rear axle brake actuators 8a, 8b as so-called Tristop brake cylinders. The parking brake module 11 regulates a parking brake pressure pBP to the first and second spring-energized actuators 12a, 12b. The spring-energized actuators 12a, 12b are usually designed such that they are pressed in the absence of pressure and open against the spring pressure if the applied pressure exceeds a certain pressure. Such spring-energized actuators 12a, 12b are known from the prior art.

[0044] In the brake system 101, the central control unit 102 is connected to a unit for autonomous driving 112 via a vehicle bus 120 and receives the target trajectory TSoll from this unit for autonomous driving. In addition, the central control unit 102 can also receive further signals, such as a deceleration target value ZSoll. The electronically controllable steering device 103 is also connected to the brake system 101 via the vehicle bus 120 and thus also communicates with the central control unit 102. In addition, as already mentioned with reference to Fig. 1, the brake system 101 also comprises a brake pedal sensor 105, which is connected to the central control unit 102 via the vehicle bus 120 and provides a brake pedal position signal pPedal. Figure 1The brake system 101 also comprises a redundancy control unit 104, which is likewise coupled here to the vehicle bus 120, as described. Furthermore, the central control unit 102 and the redundancy control unit 104 communicate directly with one another via a second bus 122 and can thus exchange signals, such as the deceleration target value ZSoll. In the event of a failure of the central control unit 102, the redundancy control unit 104 can take over the control of the brake system 101. Figure 2 In the embodiment shown in Fig. 1, the redundancy control unit 104 is integrated with the parking brake module 11. In particular, the redundancy control unit 104 also simultaneously forms the electronic control unit of the parking brake module 11. This is particularly expedient, since the parking brake module 11 in the embodiment shown here has an electronic control unit anyway. Alternatively and also preferably, however, the redundancy control unit 104 is a separate module and is not integrated with the parking brake module 11.

[0045] In the embodiment shown here, the central control unit 102 also simultaneously forms the rear axle modulator and is directly coupled to the second compressed-air reservoir 22. This is not absolutely necessary either, and the rear axle modulator can also be provided separately from the central control unit 102. The central control unit 102, which here forms the rear axle modulator, then regulates the corresponding first and second rear axle brake pressures pBHA1, pBHA2 to the rear axle HA in a wheel-specific manner on the basis of the received deceleration target value ZSoll. The electronic control unit 102 has an electronic stability regulation ESC1, which is integrated in the electronic control unit here. The electronic stability regulation ESC1 is connected to the first and second front axle wheel speed sensors 14a, 14b and to the first and second rear axle wheel speed sensors 16a, 16b. Via these wheel speed sensors, the central control unit 102 receives first, second, third and fourth wheel speed signals SW1, SW2, SW3, SW4. These wheel speed signals are used by the central control unit 102 or the electronic stability regulation ESC1 to regulate the rear axle brake pressure pBH in a wheel-specific manner to the first and second rear axle brake pressures pBHA1, pBHA2, so that the first and second rear wheels 5c, 5d do not lock.

[0046] Here, a front axle modulator 6 is provided on the front axle VA, which itself has no intelligence. The front axle modulator 6 is connected directly to the central control unit 102 via a front axle signal line 124, via which the front axle brake signal SVB is provided by the central control unit. On the basis of the front axle brake signal SVB, one or more solenoid valves inside the front axle modulator 6 are switched directly in order thus to regulate the reserve pressure pV present on the front axle modulator from the front axle modulator to the front axle brake pressure pBVA. The front axle modulator 6 is here configured as a two-channel front axle modulator and comprises a first front axle channel 6.1 and a second front axle channel 6.2. Between the first front axle channel 6.1 and the first front axle brake actuator 3a, a first front axle ABS valve 26 is connected in series. Likewise, between the second front axle channel 6.2 and the second front axle brake actuator 3b, a second front axle ABS valve 28 is connected in series. The first and second front axle ABS valves are actuated by the central control unit 102 via first and second ABS lines 126, 128 in order thus to derive or regulate from the front axle brake pressure pBVA first and second front axle brake pressures pBVA1 and pBVA2 which are regulated wheel-specifically. For this purpose, the central control unit 102 uses first and second wheel speed signals SW1, SW2 from first and second front axle wheel speed sensors 14a, 14b.

[0047] Finally, the brake system 101 has a manual brake value transmitter 105 and a manual parking brake switch 107 for manual control, which are not further described here. Both are basically known and are not further described here. In the present disclosure, particular attention is paid to aspects relating to the autonomous operation of the brake system 101.

[0048] In the event that the electronic stability control unit ESC1 of the main system comprising the central control unit 102 is not functioning or not functioning properly, the redundant control unit 104 will take over control of the brake system 101. To this end, the redundant control unit 104 is connected to the first and second rear axle wheel speed sensors 16a, 16b and receives the third and fourth wheel speed signals SW3, SW4 therefrom. Since the redundant control unit 104 is connected to the vehicle bus 102 and thus receives the target deceleration ZSoll and the target trajectory TSoll, the redundant control unit 104 is able to brake the rear axle HA in a wheel-specific and redundant manner via the spring-loaded actuators 12a, 12b in this case. To this end, the redundant control unit 104 regulates a wheel-specific rear axle brake pressure pRHA for the first and second rear wheels 5c, 5d. The redundant control unit 104 is also connected to the first and second front axle wheel speed sensors 14a, 14b and thus also receives the first and second wheel speed signals SW1, SW2 therefrom. However, the redundant control unit 104 does not actuate the first and second front axle ABS valves 26, 28. The redundant control unit 104 only regulates a redundant pressure pR to the front axle modulator 6 via the pneumatic redundant pressure line 130, which then converts this redundant pressure into a front axle redundant brake pressure pRVA in a purely pneumatic manner. This front axle redundant brake pressure is not wheel-specific on the front axle VA. This means that, in this embodiment, the front axle VA is actuated in an axle-specific manner. The redundant control unit 104 actuates the front axle VA in an axle-specific manner, while the rear axle HA is still braked in a wheel-specific manner. However, the first and second wheel speed signals SW1, SW2 are still intercepted on the front axle VA via the redundant wiring of the first and second front axle wheel speed sensors 14a, 14b and supplied by the redundant control unit 104 via the vehicle bus 120. On this basis, the electronically controllable steering device 103 can implement a lateral stabilization steering intervention on the front axle VA in order to compensate for the wheel-specific braking that is no longer present on this front axle and thus to ensure vehicle stabilization. Figure 2

[0049] In the embodiment shown here, the brake system 101 also comprises a redundant electronic stability control unit ESC2, which is connected to the redundant control unit 104 via a third bus 132 and supplies the redundant control unit with redundant stabilization signals SWR. These redundant stabilization signals can also be taken into account when regulating the rear axle redundant brake pressure pRHA and are also supplied to the electronically controllable steering device 103 via the vehicle bus 120.

[0050] From Figure 2 ​It is also known that the central control unit 102 is connected to the first voltage source 106, while the redundant control unit 104 is connected to the second voltage source 108. The first and second voltage sources 106 and 108 are separate, so that one voltage source does not fail due to the failure of the other. In addition, the central control unit 102 provides ESC signals SE1 via the vehicle bus 120, and these ESC signals can then be received by the electronically controlled steering system 103 so that these ESC signals are taken into account when regulating lateral stability steering intervention.

[0051] Figure 3 The image shows a second embodiment of a vehicle 200 including a vehicle system 100. In the following text, emphasis will be placed on the first embodiment (…). Figure 2 The main differences are as described above, while the similarities will not be further described. The same reference numerals are used for the same and similar elements, and therefore, the above description should be consulted in its entirety for these elements.

[0052] The first major difference is that in this embodiment ( Figure 3 In this embodiment, when the redundant control unit 104 takes over the control of the braking system 101, the rear axle HA is driven by the axle. This means that in this embodiment ( Figure 3 In this embodiment, the rear axle redundant braking pressure pRHA is not like that in the first embodiment ( Figure 2 The braking pressure is adjusted to meet the wheel requirements as in the example. Instead, the same redundant braking pressure, namely the rear axle redundant braking pressure pRHA, is supplied to the left and right rear wheels 5c and 5d, which in this embodiment are the first and second spring-loaded actuators 12a and 12b. Nevertheless, redundant wiring to the rear axle wheel speed sensors 16a and 16b is still provided in this embodiment. Figure 3 However, this can also be optionally omitted. For example, the redundant control unit 104 can be configured to receive the third and fourth wheel speed signals SW3 and SW4 via the vehicle bus 120, and preferably learn the steering compensation to be regulated. Then, the redundant control unit 104 can transmit the learned steering compensation as a target value in the form of steering angle or steering torque to the electronically controlled steering device 103, so that the electronically controlled steering device can regulate laterally stable steering intervention.

[0053] Furthermore, compared with the first embodiment ( Figure 2 Unlike the second embodiment, Figure 3 In the first embodiment, it is configured such that, under redundant conditions, the front axle VA can be driven wheel by wheel. Figure 2 In the second embodiment, the front axle VA is controlled by the redundant control unit 104 according to the axle ground drive in the redundant case. Figure 3 In this process, the front axle VA is braked wheel by wheel.

[0054] To this end, firstly, further ABS valves are provided, namely a first redundant ABS valve 30 and a second redundant ABS valve 32. The first redundant ABS valve 30 is connected in series between the first front axle ABS valve 26 and the first front axle brake actuator 3a. In normal operation, when the brake system 101 is controlled by the central control unit 102, the first redundant ABS valve 30 is not actuated and lets the first front axle brake pressure pBVAi regulated by the first front axle ABS valve 26 pass through and regulate the first front axle brake actuator 3a in an unaltered manner. The second redundant ABS valve 32 is connected in a corresponding manner in series between the second front axle ABS valve 28 and the second front axle brake actuator 3b. In normal operation, this second redundant ABS valve is also open and allows the second front axle brake pressure pBVA2to pass through. The first and second redundant ABS valves 30, 32 are connected via first and second redundant ABS signal lines 134, 136 to the redundant control unit 104. As in the first embodiment, the first and second front axle wheel speed sensors 14a, 14b are also redundantly connected to the redundant control unit 104, so that this receives the first and second wheel speed signals SWi, SW2. In the second embodiment shown here, it is therefore possible for the front axle VA to be driven in a wheel-specific manner by the redundant control unit 104 in the event of a redundancy. The front axle modulator 6 is again configured in a dual-channel manner and is supplied with the front axle brake pressure pBVAwhich is not further modulated to the first and second channels 6.1, 6.2 and, in this case, so that the first and second front axle ABS valves 26, 28 let the front axle brake pressure pBVApass through in an open manner, while the first and second redundant ABS valves 30, 32 modulate this pressure in order to thus provide a front axle redundant brake pressure in a wheel-specific manner as the first front axle redundant brake pressure pRVAi to the first front axle brake actuator 3a and as the second front axle redundant brake pressure pRVA2to the second front axle brake actuator 3b. Figure 3

[0055] Thus, in the first embodiment ( Figure 2 ) only the front axle VA is driven in an axle-specific manner, while the rear axle HA is driven wheel by wheel, but in the second embodiment ( Figure 3 ) only the rear axle HA is driven in an axle-specific manner, while the front axle VA is driven in a wheel-specific manner. It is understood, however, that it is also possible to have an implementation in which, in the event of a redundancy, both the front axle VA and the rear axle HA are driven in an axle-specific manner. If further axles are provided, such as a second rear axle, a second front axle or an additional axle, these can also be driven in an axle-specific manner in the event of a redundancy. It is not necessary here for all axles to be driven in an axle-specific manner in the event of a redundancy, but rather it is sufficient when only one of these axles is driven in an axle-specific manner. ​

[0056] This point is Figure 4 The text includes illustrations to illustrate this point. Figure 4 A vehicle 200, i.e., a commercial vehicle 202, is shown in a turning maneuver, comprising a vehicle system 100 according to the invention. The turning direction of the target trajectory TSoll, corresponding here to a right turn, is illustrated. A tolerance corridor TK is drawn around the target trajectory TSoll. When lateral stability steering intervention is performed by means of an electronically controlled steering mechanism 103, the vehicle 200 should be kept within this tolerance corridor TK, even in redundant configurations. Front axle steering force FV and rear axle steering force FH are drawn on the vehicle 200. Since the vehicle 200 is in redundant operation and the redundant electronic control unit 104 has taken over control, a front axle redundant braking pressure pRVA is regulated to the front axle VA, and a rear axle redundant braking pressure pRHA is regulated to the rear axle HA.

[0057] When different steering forces FV and FH are known, it is preferable to increase the braking pressure regulation of the front axle redundant braking pressure pRVA or the rear axle redundant braking pressure pRHA on the axle to which the higher steering force FV or FH is applied, either the front axle VA or the rear axle HA. For example, if the front axle steering force FV is greater than the rear axle steering force FH, it is preferable to increase the braking pressure level of the front axle redundant braking pressure pRVA. This can improve vehicle stability.

[0058] When oversteer TO is confirmed while turning along the target trajectory TSoll, it is preferable to increase the braking pressure regulation of the front axle VA and optionally also the redundant braking pressure pRVA of the front axle of the trailer 204 (see [reference]). Figure 2 Therefore, more "movement occurs via the front axle," thus alleviating oversteer (TO). Preferably, the steering is further reduced by steer towards the outside of the curve using an electronically controlled steering mechanism 103. Typically, this intervention can be achieved during normal operation by adjusting the front axle braking pressure pBVA according to wheel requirements. However, due to the embodiment shown here (… Figure 4 During redundant operation, both the front axle VA and the rear axle HA brake as axles. Therefore, in this case, the electronically controlled steering device 103 needs to perform lateral stabilization steering intervention, in which case steering is performed towards the outside of the curve so that the vehicle 200 is kept on the target trajectory TSoll or within the tolerance corridor TK.

[0059] In contrast, if understeer of vehicle 200 is confirmed (TU), it is preferable to increase the braking pressure regulation of the rear axle redundant braking pressure pRHA to the rear axle HA. Optionally, the braking pressure regulation to trailer 204 is also increased. This firstly reduces the vehicle speed, while simultaneously increasing the traction of the front axle VA, thereby eliminating understeer and keeping vehicle 200 on the target trajectory (TSoll).

[0060] Figure 5 The method 300 for decelerating and steering a vehicle 200, particularly a commercial vehicle 202, is now illustrated again purely schematically. The vehicle includes a vehicle system 100 according to one of the above-described preferred embodiments of the vehicle system 100 based on the invention.

[0061] Method 300 obtains information from the electronic stability control unit ESC1 of the pneumatic braking system 101 that is electronically controlled (see [reference]). Figure 2 and Figure 3 The failure process begins. In response, as described above, redundant front axle redundant braking pressure pRVA or rear axle redundant braking pressure pRHA is adjusted according to the axle. Simultaneously, lateral stabilization steering intervention 304 is implemented as needed, i.e., by means of electronically controlled steering device 103 as specifically described above. This ensures that the vehicle 200 subsequently maintains the vehicle within the tolerance corridor TK of the predetermined target trajectory TSoll (see...). Figure 4 )Inside.

[0062] Then, in step 305, it is checked whether vehicle 200 is still on the target trajectory TSoll. If so, return to step 305 and check again whether vehicle 200 is still on the target trajectory TSoll. However, if not, in step 306, it is checked whether there is oversteer or understeer. If oversteer TO is detected, it is preferable to increase the braking pressure regulation of the front axle redundant braking pressure pRVA to the front axle VA in step 308, while simultaneously steering towards the outside of the curve using the electronically controlled steering device 103. However, if understeer TU is detected, it is preferable to increase the braking pressure regulation of the rear axle redundant braking pressure pRHA to the rear axle HA in step 310. Subsequently, the method returns to checking whether vehicle 200 is on the target trajectory TSoll or within the tolerance corridor TK.

[0063] List of reference numerals (part of the instruction manual)

[0064] 2 First Braking Circuit

[0065] 3a, 3b First and second front axle brake actuators

[0066] 4 Second Braking Circuit

[0067] 5a, 5b first and second front wheels

[0068] 5c, 5d first and second rear wheels

[0069] 6 front axle modulator

[0070] 6.1 first front axle passage

[0071] 6.2 second front axle passage

[0072] 8a, 8b first and second rear axle brake actuators

[0073] 10 parking brake circuit

[0074] 12a, 12b first and second spring-energized actuators

[0075] 14a, 14b first and second front axle wheel speed sensors

[0076] 16a, 16b first and second rear axle wheel speed sensors

[0077] 20 first compressed air reservoir

[0078] 22 second compressed air reservoir

[0079] 24 third compressed air reservoir

[0080] 26 first front axle ABS valve

[0081] 28 second front axle ABS valve

[0082] 30 first redundant ABS valve

[0083] 32 second redundant ABS valve

[0084] 100 vehicle system

[0085] 101 electronically controllable pneumatic brake system

[0086] 102 central control unit

[0087] 104 redundant control unit

[0088] 106 first voltage source

[0089] 108 second voltage source

[0090] 110 target trajectory control

[0091] 112 unit for autonomous driving

[0092] 114 secondary front axle brake control

[0093] 116 secondary rear axle brake control section

[0094] 118 secondary trailer brake control section

[0095] 120 vehicle bus

[0096] 122 second bus

[0097] 124 front axle signal line

[0098] 126 first ABS signal line

[0099] 128 second ABS signal line

[0100] 130 pneumatic redundant pressure line

[0101] 132 third bus

[0102] 134 first redundant ABS signal line

[0103] 136 second redundant ABS signal line

[0104] 200 vehicle

[0105] 202 commercial vehicle

[0106] 204 trailer

[0107] 300 method

[0108] 301-310 steps

[0109] 11 parking brake module

[0110] 103 electronically controllable steering system

[0111] ESC1 electronic stability control

[0112] ESC2 redundant electronic stability control

[0113] FH front axle steering force

[0114] FV rear axle steering force

[0115] HA rear axle

[0116] HA2 further rear axle

[0117] LW steering wheel angle

[0118] LM steering torque

[0119] pBHA rear axle brake pressure

[0120] pBHA1 first rear axle brake pressure

[0121] pBHA2 second rear axle brake pressure

[0122] pBP parking brake pressure

[0123] pBVA front axle brake pressure

[0124] pBVA1 first front axle brake pressure

[0125] pBVA2 second front axle brake pressure

[0126] pRHA rear axle redundant brake pressure

[0127] pRVA front axle redundant brake pressure

[0128] pRVA1 first front axle redundant brake pressure

[0129] pRVA2 second front axle redundant brake pressure

[0130] TO oversteer

[0131] TK tolerance band

[0132] TSoll target trajectory

[0133] TU understeer

[0134] SBR redundant brake signal

[0135] SER redundant ESC signal

[0136] SVB front axle brake signal

[0137] SW1 first wheel rotational speed signal

[0138] SW2 second wheel rotational speed signal

[0139] SW3 third wheel rotational speed signal

[0140] SW4 fourth wheel rotational speed signal

[0141] VA front axle

[0142] WSoll target value for steering intervention for lateral stability

[0143] ZSoll deceleration target value

Claims

1. Vehicle system (100) for a vehicle (200), the vehicle system having: an electronically controllable pneumatic brake system (101) and an electronically controllable steering device (103), wherein the electronically controllable pneumatic brake system (101) having at least one first brake circuit (2), at least one second brake circuit (4), a central control unit (102) for controlling the first and second brake circuits (2, 4), and at least one first and second front axle brake actuator (3a, 3b) for at least one first and second front wheel (5a, 5b) on at least one front axle (VA) and at least one first and second rear axle brake actuator (8a, 8b) for at least one first and second rear wheel (5c, 5d) on at least one rear axle (HA), wherein the central control unit (102) has or is connected to an electronic stability control (ESC1) which is configured to act wheel-specifically on the first and second front axle brake actuators (3a, 3b) and / or the first and second rear axle brake actuators (8a, 8b), wherein the electronically controllable pneumatic brake system further comprises a redundant control unit (104) which, in the event of a failure of the electronic stability control (ESC1) during driving of the vehicle (200), controls the first brake circuit (2) and / or the second brake circuit (4), characterized in that, in the event of a failure of the electronic stability control (ESC1) during driving of the vehicle (200), the redundant control unit (104) actuates the front axle (VA) with a front axle redundant brake pressure (pRVA) and / or the rear axle (HA) with a rear axle redundant brake pressure (pRHA) and the electronically controllable steering device (103) implements a lateral stability steering intervention for keeping the vehicle (200) within a tolerance corridor (TK) of a predetermined target trajectory (TSoll) of the vehicle (200), wherein the electronically controllable steering device (103) is connected to the central control unit (102) for receiving an ESC signal (SE1) of the electronic stability control (ESC1) or for receiving a signal derived or extracted from the ESC signal of the electronic stability control.

2. The vehicle system (100) according to claim 1, wherein the electronically controllable steering device (103) receives a steering wheel angle (LW) and / or a steering torque (LM) as a target value (WSoll) for the lateral stability steering intervention and adjusts the target value of the lateral stability steering intervention.

3. Vehicle system (100) according to claim 1 or 2, having a redundant electronic stability control (ESC2) which is connected to the redundant control unit (104) and provides the redundant control unit with a redundant ESC signal (SER).

4. The vehicle system (100) according to claim 3, wherein The electronically controllable steering device (103) is connected with the redundant control unit (104) and / or with the redundant electronic stability control (ESC2) for receiving redundant ESC signals (SER).

5. The vehicle system (100) according to claim 1 or 2, wherein The central control unit (102) is connected with a first voltage source (106) and the redundant control unit (104) is connected with a second voltage source (108) which is independent of the first voltage source (106).

6. The vehicle system (100) of claim 5, wherein, The electronically controllable steering device (103) or a part of the electronically controllable steering device is connected with the second voltage source (108).

7. The vehicle system (100) according to claim 1 or 2, wherein The redundant control unit (104) is connected with first and / or second wheel rotational speed sensors (14a, 14b, 16a, 16b) for receiving wheel rotational speed signals (SW1, SW2, SW3, SW4).

8. The vehicle system (100) according to claim 1 or 2, further having a parking brake circuit (10) with a parking brake module (11) connected to the central control unit (102) and at least first and second spring-energized actuators (12a, 12b) on at least the rear axle (HA) or a further rear axle (HA2), wherein The redundant control unit (104) forms or is integrated with an electronic control unit of the parking brake module (11).

9. The vehicle system (100) according to claim 1 or 2, wherein In the event of a failure of the electronic stability control (ESC1), the redundant control unit (104) provides a front axle redundant brake pressure (pRVA) to the first and second front axle brake actuators (3a, 3b) in order to brake the front axle (VA) accordingly in an axle-specific manner when regulating the front axle redundant brake pressure (pRVA) axle-specifically.

10. The vehicle system (100) of claim 1, wherein, The vehicle system (100) is for a commercial vehicle (202).

11. Method (300) for decelerating and steering a vehicle (200) having a vehicle system (100) according to any one of claims 1 to 10, the method comprising the steps of: - detecting (301) a failure of an electronic stability control (ESC1) of an electronically controllable pneumatic brake system (101), in response to the detected failure: - regulating (302) a redundant front axle brake pressure (pRVA) to at least one front axle (VA) and / or a redundant rear axle brake pressure (pRHA) to at least one rear axle (HA) redundantly and axle-specifically by means of a redundant control unit (104) of the electronically controllable pneumatic brake system (101), and - implementing a laterally stabilizing steering intervention (304) by means of an electronically controllable steering device (103) in order to keep the vehicle (200) within a tolerance corridor (TK) of a predetermined target trajectory (TSoll) of the vehicle (200).

12. The method according to claim 11, the method comprising the steps of: - detecting a front axle steering force (FV) on the front axle (VA); - detecting a rear axle steering force (FH) on the rear axle (HA); wherein, the redundant control unit (104) increasing the brake pressure regulation (pRVA, pRHA) to the axle on which the higher one of the front axle steering force (FV) and the rear axle steering force (FH) is detected.

13. The method according to claim 11 or 12, the method comprising the steps of: - that the vehicle (200) is understeering (TU); and in response: - increasing the brake pressure regulation (pRVA, pRHA) of the redundant front axle brake pressure (pRVA) to the front axle (VA) and optionally also to the trailer (204); and - steering by means of the electronically controllable steering device (103) to the outside of the bend.

14. The method according to claim 11 or 12, comprising the steps of: - that the vehicle (200) is understeering (TU); and in response: - increasing the brake pressure regulation (pRVA, pRHA) of the redundant rear axle brake pressure (pRHA) to the rear axle (HA) and optionally also to the trailer (204).

15. The method of claim 11, wherein, The vehicle is a commercial vehicle (202).

16. Vehicle (200) having a vehicle system (100) according to any one of claims 1 to 10.

17. The vehicle of claim 16, wherein, The vehicle is a commercial vehicle (202).

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