VEHICLE SYSTEM WITH AN ESC FAULT-TOLERANT BRAKING SYSTEM

Description

[0001] The invention relates to a vehicle system for a vehicle, in particular a commercial vehicle according to the preamble of claim 1.

[0002] In particular, such a vehicle system comprises an electronically controllable pneumatic braking system and an electronically controllable steering device, wherein the electronically controllable pneumatic braking system comprises 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, as well as 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 further comprises or is connected to an electronic stability control system, which is designed to actuate the first and second front axle brake actuators and / or the first and second rear axle brake actuators on a wheel-individual basis.Furthermore, the electronically controllable pneumatic braking system comprises a redundant control unit that controls the first brake circuit and / or the second brake circuit in the event of a failure of the electronic stability control while the vehicle is traveling. The invention further relates to a method for decelerating and steering a vehicle, in particular a commercial vehicle, preferably comprising a vehicle system of the type mentioned above, as well as to a vehicle, in particular a commercial vehicle, comprising a vehicle system of the type mentioned above.

[0003] Commercial vehicles typically use pneumatic braking systems with 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 for a first brake circuit to be provided for the left side of the vehicle and a second brake circuit for the right side of the vehicle. A crossover connection may also be preferred. Furthermore, electronically controllable pneumatic braking systems can also have a third brake circuit, which is provided, for example, for a parking brake device and / or supplies a trailer.

[0004] As vehicles become increasingly autonomous, especially those operating at SAE Level 3, 4, or 5, it is essential that such braking systems can brake safely even in the event of a fault, i.e., when one or more modules, electrical control units, or other components fail. Known solutions for so-called FOBS (Fail-Operational Brake Systems) primarily aim to ensure residual availability in the event of single faults in order to restore the vehicle to a safe state. The resulting residual performance is often severely degraded. Electronic stability control systems are usually no longer guaranteed.

[0005] For example, systems are known that, in the event of a fault in a central control unit, transfer control to an electronic control unit of another module, such as a front-axle or rear-axle modulator. There are also systems in which an electronic control unit of a parking brake module takes over control of the braking system in the event of a fault in the central module. Furthermore, systems exist that establish purely pneumatic redundancies, for example, by transferring pressure from one axle to another axle in order to at least pneumatically control a redundant pressure.

[0006] Other approaches utilize systems that are designed entirely in parallel. In such systems, two braking systems are configured in parallel and act on individual brake actuators, for example, via shuttle valves. While these systems are fully integrated and can replicate most of the functionality of the primary braking system, they require a high level of assembly and wiring effort, making them costly.

[0007] The object of the present invention is to provide a braking system with high residual availability, which can perform stability functions even in the event of a fault.

[0008] The invention achieves the object in a vehicle system of the type mentioned at the outset in that, in the event of failure of the electronic stability control while the vehicle is traveling, the redundant control unit controls at least the front axle with a front axle redundancy brake pressure and / or the rear axle with a rear axle redundancy brake pressure on an axle-by-axle basis, and in that the electronically controllable steering device carries out transversely stabilizing steering interventions to keep the vehicle within a tolerance corridor of a predetermined target trajectory of the vehicle.

[0009] The invention is based on the idea of ​​creating a fault-tolerant braking system in which, in the fallback level, when the electronic stability control of the primary system is no longer available, transverse stabilizing control interventions are carried out via a combination of axle-by-axle pressure controls on at least one axle and superimposed steering interventions via an automated steering system. The first brake circuit is preferably provided for the front axle and is connected to the first and second front-axle brake actuators to supply them with brake pressure. The second brake circuit is preferably provided for the rear axle and is accordingly connected to the first and second rear-axle brake actuators to supply them with brake pressure.However, it should be understood that other configurations are also possible, for example the first brake circuit can also be provided for the first brake actuator on the left front wheel and the second brake actuator on the right rear wheel, while the second brake circuit can be provided for the second front axle brake actuator on the right front wheel and the first rear axle brake actuator on the left rear wheel. Exchange page 3a (to be inserted on page 3 after the first paragraph)

[0010] WO2019092150A1 describes a system for controlling at least partially autonomous operation of a motor vehicle, comprising at least one sensor device with which environmental data characterizing the environment of the motor vehicle can be generated, an electronic main control unit which receives the environmental data from the sensor device and, depending on the environmental data, inputs control commands to at least one device or to at least one actuator which is used in the at least partially autonomous operation of the motor vehicle, a first electronic backup control unit which, in the event of an error or failure of the electronic main control unit, receives the environmental data from the sensor device and, depending on the environmental data, inputs control commands to the at least one device or to the at least one actuator,which is used in the at least partially autonomous operation of the motor vehicle, wherein a second electronic backup control unit, which in the event of a fault or failure of the main electronic control unit and the first electronic backup control unit, receives the environmental data from the sensor device and, depending on the environmental data, sends control commands to the at least one device or to the at least one actuator, which is used in the at least partially autonomous operation of the motor vehicle. Both the first and the second brake circuits are controlled by the central control unit, which in turn can receive braking commands from a higher-level unit, such as in particular a unit for autonomous driving. The central control unit has an electronic stability control system that enables wheel-individual braking in certain braking situations. This means,Different brake pressures are supplied to the first and second front axle brake actuators and to the first and second rear axle brake actuators in order to brake individually for each wheel in order to ensure the stability of the vehicle.

[0011] In the event that this electronic stability control system fails, for example, because the central control unit fails, because wheel speed sensors on one or more wheels fail, or because of other errors that impair the electronic stability control system, the redundant control unit takes over control of the braking system, in particular the control of the first and second brake circuits. If the redundant control unit takes over control, it controls at least one of the axles, i.e., the front axle and / or the rear axle, on an axle-by-axle basis. This means that the same brake pressure is provided to the corresponding brake actuators on the at least one axle that is controlled on an axle-by-axle basis.For example, if only the front axle is controlled axle-by-axle, the redundant control unit ensures that the same brake pressure is applied to the first front axle brake actuator and the second front axle brake actuator, regardless of any differing wheel speeds. Likewise, the rear axle can be controlled axle-by-axle, so that the same brake pressure is applied to the first and second rear axle brake actuators. In the case of axle-by-axle control, the front axle redundancy brake pressure and the rear axle redundancy brake pressure are controlled accordingly. If the vehicle also has a second front axle, this can also be controlled axle-by-axle, as can a second rear axle, additional axle, and the like.If, for example, the vehicle has five axles, a total of ten brake actuators are preferably provided, whereby each axle can be controlled individually on an axle-by-axle basis or the control of axles can be combined into one or more axle groups. However, within the scope of the invention, it can also be provided that only one axle is controlled on an axle-by-axle basis and that individual wheel braking is still possible for the other axles, for example by means of redundant wheel speed sensors and an at least partially redundant electronic stability control system. However, within the scope of the invention, at least one axle is controlled on an axle-by-axle basis. In order to nevertheless ensure the stability of the vehicle, the electronically controllable steering device is prompted to carry out transverse stabilizing steering interventions in order to keep the vehicle within a tolerance corridor of the predetermined target trajectory of the vehicle.The electronically controlled steering system therefore compensates for the braking on the axle controlled individually by appropriate steering interventions. This makes it easy to implement stability functionality in the braking system even if the primary system's electronic stability control fails.

[0012] The target trajectory and the tolerance corridor for the target trajectory are preferably provided by a unit for autonomous driving, for example, via a vehicle bus. They can be provided at the central control unit, the redundant control unit, and / or at or by the electronically controllable steering system. Preferably, all three modules receive the target trajectory and the tolerance corridor. The electronically controllable steering system carries out the transverse stabilizing steering interventions if the electronic stability control of the primary system has failed. It can also be provided that the electronically controllable steering system is also used additionally while the electronic stability control of the primary system is functioning, thus achieving additional functionalities.

[0013] In a first preferred embodiment, the electronically controllable steering device receives a steering wheel angle and / or a steering torque as a setpoint for the transverse-stabilizing steering interventions and regulates this or that. For this purpose, the electronically controllable steering device is preferably connected to the electronically controllable pneumatic braking system, preferably the redundant control unit, the electronic stability control system or a redundant electronic stability control system and / or a unit for autonomous driving, and is configured to receive the steering wheel angle and / or the steering torque as a setpoint. The electronically controllable steering device is then preferably further configured to process these and to regulate the transverse-stabilizing steering interventions in accordance with these.This setpoint is preferably provided by the electronically controllable pneumatic braking system, preferably the redundant control unit, the electronic stability control or a redundant electronic stability control.

[0014] According to the invention, the electronically controllable steering device is connected to the central control unit for receiving ESC signals from the electronic stability control system or signals derived or processed therefrom. Such a derived or processed signal can, in particular, be an additional steering signal (e.g., steering wheel angle and / or steering torque). Preferably, the electronically controllable steering device is also connected to the redundant control unit in order to receive redundant ESC signals or other signals therefrom, if necessary, or to provide the received ESC signals or the signals derived or processed therefrom to the redundant control unit.

[0015] Furthermore, it is preferred that the vehicle system has a redundant electronic stability control system that is connected to the redundant control unit and provides redundant ESC signals thereto. The redundant control unit preferably has the redundant electronic stability control system. The redundant ESC signals can be used, on the one hand, to control axles that are not controlled axle-by-axle on a wheel-by-wheel basis. On the other hand, the redundant ESC signals can also be used to compensate for the transverse-stabilizing steering interventions by means of the electronically controllable steering device. For this purpose, the electronically controllable steering device can be designed to take the redundant ESC signals into account when compensating for the transverse-stabilizing steering interventions.

[0016] Accordingly, the electronically controllable steering device is preferably connected to the redundant control unit or the redundant electronic stability control for receiving redundant ESC signals.

[0017] 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 that 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, distinct, and independent voltage sources. If, for example, the electronic stability control of the central control unit fails because the first voltage source of the central control unit fails, this aspect ensures that the redundant control unit continues to be supplied with voltage. This increases the reliability of the vehicle system.

[0018] 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 by both the first voltage source and the second voltage source. It is therefore capable of continuing to operate with the second voltage source even if the first voltage source fails, in order to compensate for the transverse stabilizing steering interventions.

[0019] According to a further preferred embodiment, the redundant control unit is connected to first and / or second wheel speed sensors for receiving wheel speed signals. Preferably, first wheel speed sensors are arranged on the front axle and second wheel speed sensors on the rear axle. In particular, a wheel sensor is arranged on each front wheel of the front axle, namely first and second front axle wheel speed sensors. On the rear axle, a wheel speed sensor is preferably arranged on each rear wheel, namely first and second rear axle wheel speed sensors. These each provide a wheel speed signal, preferably to the redundant control unit. The first and second wheel speed sensors preferably also provide the wheel speed signals to the central control unit and, if necessary, to other modules, such as in particular the unit for autonomous driving.It is also conceivably preferable to provide these signals via a vehicle bus.

[0020] Preferably, the vehicle system further comprises a parking brake circuit with a parking brake module connected to the central control unit, as well as at least first and second spring-loaded actuators at least on the rear axle or another rear axle, wherein the redundant control unit forms an electronic control unit of the parking brake module or is integrated therewith. The parking brake module is preferably connected to a third compressed air supply and part of a third brake circuit. The spring-loaded actuators are preferably integrated with the first and second rear axle brake actuators to form so-called Tristop brake actuators. According to this aspect, the redundant control unit is preferably integrated with or identical to the electronic control unit of the parking brake module.The parking brake module is preferably designed to take over control of the braking system in a redundant situation, when the central control unit is not functioning or is not functioning properly. Therefore, the parking brake module is preferably also connected to the autonomous driving unit and the central control unit and receives the same signals.

[0021] InIn a further preferred embodiment, it is provided that, in the event of a failure of the electronic stability control system, the redundant control unit provides the front-axle redundancy brake pressure to the first and second front-axle brake actuators during the axle-by-axle control of the rear-axle redundancy brake pressure, in order to brake the front axle axle-by-axle. The same preferably also applies to the rear axle. Accordingly, it is preferably provided that, in the event of a failure of the electronic stability control system, the redundant control unit provides the rear-axle redundancy brake pressure to the first and second rear-axle brake actuators during the axle-by-axle control of the rear-axle redundancy brake pressure, in order to brake the rear axle axle-by-axle.

[0022] In a second aspect, the invention solves the problem mentioned above by a method for decelerating and steering a vehicle of the type mentioned above, comprising the steps of: determining a failure of an electronic stability control system of an electronically controllable pneumatic braking system; in response to determining the failure: redundantly controlling a redundant front axle brake pressure on at least one front axle and / or a redundant rear axle brake pressure on at least one rear axle by means of a redundant control unit of the electronically controllable pneumatic braking system, and carrying out transverse stabilizing steering interventions by an electronically controllable steering device to keep the vehicle within a tolerance corridor of a predetermined target trajectory of the vehicle.

[0023] The redundant rear axle brake pressure can be controlled by a parking brake module or by another module, such as a rear axle modulator. The redundant rear axle brake pressure can be provided to both spring-loaded brake cylinders and service brake cylinders on the rear axle. All combinations are conceivable and preferred.

[0024] It should 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 similar sub-aspects, as particularly set forth in the dependent claims. Therefore, for preferred embodiments of the method according to the second aspect of the invention, reference is also made in full to the above description of the vehicle system according to the first aspect of the invention.

[0025] The method preferably further comprises the steps of: determining a front axle cornering force on the front axle; determining a rear axle cornering force on the rear axle; wherein the redundant control unit increases the brake pressure control on the vehicle axle, from the front axle and rear axle, at which the higher of the front axle cornering force and the rear axle cornering force is determined. The cornering forces can be determined, for example, from the vehicle model. The cornering force is a dynamic variable that depends on a slip angle, a wheel load, slip, a wheel camber, and friction values. The cornering force is an output variable of the vehicle model, which is calculated based on various dynamic sensor data (e.g., lateral or longitudinal acceleration, yaw rate, steering angle, wheel speed, vehicle speed, etc.) and static variables such as vehicle mass, center of gravity, wheelbase, vehicle geometry, etc.Describes the dynamic vehicle condition. Depending on which axle has the higher cornering force, the applied brake pressure is increased or the brake pressure distribution on the axles is redistributed in favor of the axle with the higher cornering force. This means that if, for example, the cornering force is higher on the front axle than on the rear axle, the redundant control unit increases the front axle's redundant brake pressure.

[0026] According to the invention, the method comprises the steps of: detecting vehicle oversteer; and in response thereto: increasing the brake pressure control of the redundant front axle brake pressure on the front axle and optionally on a trailer; and steering using the electronically controllable steering device in the outside direction of the curve. This can reduce oversteer and keep the vehicle stable on the path, even if the front axle redundancy brake pressure is only controlled on the front axle for each axle. Steering in the outside direction of the curve using the electronically controllable steering device then constitutes a transversely stabilizing steering intervention within the meaning of the invention.Additionally or alternatively, the braking of the trailer can be used to achieve a stretch stop. Furthermore, the method according to the invention comprises the steps of: determining understeering of the vehicle; and in response thereto: increasing the brake pressure control of the redundant rear axle brake pressure on the rear axle and optionally on a trailer. In order to recover from understeering, no transverse stabilizing steering intervention of the electronically controllable steering device is required in this embodiment. Rather, it is sufficient to increase the brake pressure control of the redundant rear axle brake pressure, in particular in the case when the rear axle is controlled axle by axle. This decelerates the vehicle and reduces understeer. Optional additional braking of a trailer, which may be connected to the vehicle, can be provided.In one variant, this can be used to quickly reduce the speed of the vehicle and trailer. However, it is also conceivable to intentionally allow the trailer to slide slightly with increased brake pressure on the rear axle of the vehicle in order to further reduce understeer. Another way to reduce understeer can be achieved with the following steps: setting a steering angle of approximately 0°; increasing brake pressure on preferably all axles to a maximum value that preferably still allows stable driving, i.e. preferably with no or only slight slip; both for a short period of time; and then: adjusting a steering wheel angle to bring the vehicle trajectory closer to a planned vehicle trajectory.In this variant, it is accepted that the vehicle will drift slightly too far to the outside of the curve, but the brief and sharp reduction in speed preferably brings the vehicle back to a stable state, so that the vehicle can be guided back onto the planned trajectory with appropriate steering intervention. These variants can also be combined. For example, simply increasing the brake pressure on the rear axle can also reduce the steering angle to bring the vehicle back to a stable state.

[0027] In a third aspect, the object mentioned above is achieved by a vehicle, in particular a commercial vehicle, having a vehicle system according to one of the above-described preferred embodiments of a vehicle system according to the first aspect of the invention. Preferably, the vehicle system according to the first aspect of the invention, which is used in the vehicle according to the third aspect of the invention, is designed to implement the method according to the second aspect of the invention.

[0028] It should be understood that the vehicle system according to the first aspect of the invention, the method according to the second aspect of the invention, and the vehicle according to the third aspect of the invention have the same and similar sub-aspects, as particularly set forth in the dependent claims. Therefore, reference is made in full to the above description for particular embodiments as well as further features and their advantages of the vehicle.

[0029] Embodiments of the invention will now be described with reference to the drawings. These are not necessarily intended to represent the embodiments to scale; rather, the drawings are schematic and / or slightly distorted where this is useful for explanation. With regard to additions to the teachings immediately apparent from the drawings, reference is made to the relevant prior art. It should be noted that various modifications and changes to the form and detail of an embodiment can be made without departing from the general idea of ​​the invention. The features of the invention disclosed in the description, the drawings and the claims can be essential for further developing the invention, both individually and in any combination.Furthermore, all combinations of at least two of the features disclosed in the description, the drawings and / or the claims fall within the scope of the invention. The general idea of ​​the invention is not limited to the exact form or detail of the preferred embodiments shown and described below, or limited to an object that would be limited compared to the object claimed in the claims. In specified dimensioning ranges, values ​​lying within the stated limits are also intended to be disclosed as limit values ​​and to be used and claimed as desired. For the sake of simplicity, the same reference numerals are used below for identical or similar parts or parts with identical or similar functions.

[0030] Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawings, which show: Fig. 1 shows a schematic system layout of the invention; Fig. 2 shows a vehicle with a vehicle system according to the invention; Fig. 3 shows a vehicle with a vehicle system in a second embodiment; Fig. 4 shows a vehicle cornering; and Fig. 5 shows a schematic sequence of a method.

[0031] Fig. 1 first illustrates the general structure in the form of a block diagram of the vehicle system 100. The vehicle system 100 comprises a central control unit 102, which is used to control the electronically controllable pneumatic braking system 101 (cf. Figures 2 and 3 ) is provided. The central control unit 102 receives a target trajectory TSoll from a target trajectory controller 110. The target trajectory controller 110 can, for example, be part of a unit for autonomous driving 112 (see Figures 2 and 3), but can also be provided separately within the vehicle 200. Furthermore, it is possible for the target trajectory controller 110 to be provided in a cloud service or to be supplied with data via such a service, on the basis of which the target trajectory TSoll is then generated. The vehicle system 100 also includes an electronically controllable steering device 103. The electronically controllable steering device 103 also receives the target trajectory TSoll from the target trajectory controller 110. The electronically controllable steering device 103 is provided for steering the vehicle 200 and can act on one or more axles.

[0032] Within the scope of the invention, a redundant control unit 104 is also provided, which in the event that an electronic stability control ESC1 of the central control unit 102 (cf. Figures 2 and 3) fails and / or no longer functions properly, takes over control of the braking system 101. The redundant control unit 104 accordingly 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 when the vehicle 200 is used to tow a trailer 204 (cf. Fig. 2 ). Otherwise, it 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, as is generally known. They are in Fig. 1 not shown in detail.

[0033] Optionally, a redundant electronic stability control system ESC2 is also provided, which is connected here to the redundant control unit 104. The redundant electronic stability control system ESC2 can provide redundant ESC signals SER to the redundant control unit 104, as will be described in more detail later. The redundant control unit 104 is further connected to the electronically controllable steering device 103 and provides redundant braking signals SBR thereto, which the redundant control unit 104 preferably also provides to corresponding additional modules in the braking system 101 for braking specific axles.

[0034] The redundant control unit 104 is provided to control at least one of the axles, in particular the front axle VA and the rear axle HA, axle by axle in the case of redundancy, i.e., when the redundant control unit 104 takes over control of the braking system 101. When an axle VA, HA is controlled axle by axle, the same brake pressures are regulated at the corresponding brake actuators of this axle VA, HA. Wheel-specific braking then no longer occurs on this axle. For this reason, the redundant control unit 104 is connected to the electronically controllable steering device 103, which then, in this case, carries out transverse-stabilizing steering interventions to keep the vehicle 200 within a tolerance corridor TK of a predetermined target trajectory TSoll (cf. Fig. 4). While in normal operation the central control unit 102 can independently control the braking system 101 and allows wheel-specific braking, in the case of redundancy the redundant control unit 104 and the electronically controllable steering device 103 act together to keep the vehicle 200 on the target trajectory TSoll.

[0035] In addition to the target trajectory TSoll, the electronically controllable steering device 103 can also receive a steering wheel angle LW and a steering torque LM as a target value WSoll for the transverse stabilizing steering interventions and regulate them.

[0036] Now that the vehicle system 100 has been described in its basic concept, the Figures 2 and 3Two concrete implementations of the vehicle system 100 in a vehicle 200, namely in particular in a commercial vehicle 202. The commercial vehicle 202 comprises an electronically controllable pneumatic braking system 101, as fundamentally described above. The electronically controllable pneumatic braking system has a first brake circuit 2, here in the form of a front axle brake circuit for the front axle VA, and a second brake circuit 4, here 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 supply 20. The first compressed air supply 20 provides a supply pressure pV. First and second front axle brake actuators 3a, 3b are also 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. The first brake circuit 2 represents in this embodiment ( Fig. 2 ) provides a front axle brake pressure pBVA, more precisely a first front axle brake pressure pBVA1 at the first front axle brake actuator 3a and a second front axle brake pressure pBVA2 at the second front axle brake actuator 3b.

[0037] The second brake circuit 4, here the rear axle brake circuit, is supplied by a second compressed air reservoir 22, which also provides a reservoir pressure pV. First and second rear axle brake actuators 8a, 8b are provided on the rear axle HA and are controlled by the second brake circuit 4. The first rear axle brake actuator 8a is provided for a first rear wheel 5c, and the second rear axle brake actuator 8b is provided for a second rear wheel 5d. The second brake circuit 4 provides a first rear axle brake pressure pBHA1 at the first rear axle brake actuator 8a and a second rear axle brake pressure pBHA2 at the second rear axle brake actuator 8b, depending on the wheel. Due to the wheel-specific control of the brake pressures pBVA1, pBVA2, pBHA1 and pBHA2, the vehicle 200 is held on the target trajectory TSoll, which is provided by the target trajectory control 110 of the central control unit 102.

[0038] In the illustrated embodiment, the braking system 101 also includes a parking brake circuit 10, which is supplied by a third compressed air supply 24. The third compressed air supply 24 also provides a supply pressure pV. The parking brake circuit 10 has a parking brake module 11, which receives the supply pressure pV from the third compressed air supply 24. The parking brake circuit 10 further has first and second spring-loaded actuators 12a, 12b on the rear axle HA of the vehicle 200. In the illustrated embodiment, Fig. 2In the embodiment shown, the first and second spring-loaded actuators 12a, 12b are integrated with the first and second rear axle brake actuators 8a, 8b to form so-called Tristop brake cylinders. The parking brake module 11 controls a parking brake pressure pBP to the first and second spring-loaded actuators 12a, 12b. Spring-loaded actuators 12a, 12b are generally designed to apply without pressure and to open against the pressure of a spring when a pressure exceeds a certain pressure is applied. Such spring-loaded actuators 12a, 12b are well known in the art.

[0039] In the braking system 101, the central control unit 102 is connected to the autonomous driving unit 112 via a vehicle bus 120 and receives the target trajectory TSoll from it. 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 braking system 101 via the vehicle bus 120 and is thus also in communication with the central control unit 102. Furthermore, the braking system 101 comprises, as already described with reference to Fig. 1 described, a redundant control unit 104, which is also connected to the vehicle bus 120. In addition, the central control unit 102 and the redundant control unit 104 communicate directly with each other via a second bus 122 and can thus exchange signals, such as the deceleration setpoint ZSoll. In the Fig. 2In the embodiment shown, the redundant control unit 104 is integrated with the parking brake module 11. In particular, the redundant control unit 104 simultaneously also forms an electronic control unit of the parking brake module 11. This is particularly expedient since the parking brake module 11 already has an electronic control unit in the embodiment shown here. Alternatively, and likewise preferably, the redundant control unit 104 is a separate module and not integrated with the parking brake module 11.

[0040] In the exemplary embodiment shown here, the central control unit 102 also simultaneously forms a rear axle modulator and is directly connected to the second compressed air supply 22. This is also not absolutely necessary, and the rear axle modulator could equally well be provided separately from the central control unit 102. The central control unit 102, which here forms the rear axle modulator, then controls corresponding first and second rear axle brake pressures pBHA1, pBHA2 on the rear axle HA based on the receipt of a deceleration setpoint value ZSoll. The electronic control unit 102 has an electronic stability control system ESC1, which is integrated into it here. The electronic stability control system ESC1 is connected to first and second front axle wheel speed sensors 14a, 14b and first and second rear axle wheel speed sensors 16a, 16b.Via these, the central control unit 102 receives first, second, third, and fourth wheel speed signals SW1, SW2, SW3, SW4. These are used by the central control unit 102 or the electronic stability control system ESC1 to achieve a wheel-specific control of the rear axle brake pressure pBHA into the first and second rear axle brake pressures pBHA1, pBHA2, so that the first and second rear wheels 5c, 5d do not lock.

[0041] A front axle modulator 6 is provided on the front axle VA, which does not have its own intelligence. The front axle modulator 6 is directly connected to the central control unit 102 via a front axle signal line 124, via which front axle brake signals SVB are provided. Based on the front axle brake signals SVB, one or more electromagnetic valves within the front axle modulator 6 are directly switched in order to control a front axle brake pressure pBVA from the reservoir pressure pV applied to it. The front axle modulator 6 is designed here as a two-channel front axle modulator and comprises a first front axle channel 6.1 and a second front axle channel 6.2. A first front axle ABS valve 26 is connected between the first front axle channel 6.1 and the first front axle brake actuator 3a. Likewise, a second front axle ABS valve 28 is connected between the second front axle channel 6.2 and the second front axle brake actuator 3b.The first and second front-axle ABS valves are controlled by the central control unit 102 via first and second ABS lines 126, 128 in order to derive or control the first and second front-axle brake pressures pBVA1 and pBVA2, which are controlled individually for each wheel, from the front-axle brake pressure pBVA. For this purpose, the central control unit 102 uses the first and second wheel speed signals SW1, SW2 from the first and second front-axle wheel speed sensors 14a, 14b.

[0042] Finally, for manual control, which will not be described further here, the braking system 101 includes a manual brake value transmitter 105 and a manual parking brake switch 107. Both are known in the art and will not be described further here. Of particular interest in the present disclosure are the aspects relating to the autonomous operation of the braking system 101.

[0043] In the event that the electronic stability control ESC1 of the primary system, comprising the central control unit 102, is not functioning or is not functioning correctly, the redundant control unit 104 takes over control of the braking system 101. For this purpose, the redundant control unit 104 is wired to the first and second rear axle wheel speed sensors 16a, 16b and receives the third and fourth wheel speed signals SW3, SW4 from them. Since the redundant control unit 104 is connected to the vehicle bus 102 and thus receives both the target deceleration Ztarget and the target trajectory Ttarget, the redundant control unit 104 is able, in this case, to brake the rear axle HA individually and redundantly for each wheel via the spring-loaded actuators 12a, 12b. For this purpose, the redundant control unit 104 controls a redundant rear axle brake pressure pRHA individually 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 from them. However, the redundant control unit 104 cannot control the first and second front-axle ABS valves 26, 28. The redundant control unit 104 can only control a redundancy pressure pR at the front-axle modulator 6 via a pneumatic redundancy pressure line 130, which is then converted purely pneumatically into the front-axle redundancy brake pressure pRVA. This is not wheel-specific on the front axle VA. This means that in this embodiment (. Fig. 2), the front axle VA is controlled axle by axle. The redundant control unit 104 controls the front axle VA axle by axle, while the rear axle HA is still braked individually for each wheel. However, at the front axle VA, the first and second wheel speed signals SW1, SW2 are still tapped via the redundant cabling with the first and second front axle wheel speed sensors 14a, 14b and provided by the redundant control unit 104 via the vehicle bus 120. Based on this, the electronically controllable steering device 103 can then carry out transversely stabilizing steering interventions for the front axle VA in order to compensate for the wheel-individual braking that is no longer present there and thus ensure vehicle stability.

[0044] In the exemplary embodiment shown here, the braking system 101 also includes a redundant electronic stability control ESC2, which is connected to the redundant control unit 104 via a third bus 132 and provides redundant stability signals SWR to the latter. These can also be taken into account when controlling the rear axle redundancy brake pressure pRHA and can also be provided to the electronically controllable steering system 103 via the vehicle bus 120.

[0045] As can be seen from Fig. 2The central control unit 102 is connected to a first voltage source 106, while the redundant control unit 104 is connected to a second voltage source 108. The first and second voltage sources 106, 108 are separate, so that one voltage source does not fail due to a fault in the other. Furthermore, the central control unit 102 provides ESC signals SE1 via the vehicle bus 120, which can then be received by the electronically controllable steering device 103 in order to take them into account when controlling the transverse stabilizing steering interventions.

[0046] A second embodiment of the vehicle 200, which includes a second embodiment of the vehicle system 100, is shown in Fig. 3 The following describes the main differences to the first embodiment ( Fig. 2) are highlighted, while similarities are not described further. The same reference numerals are used for identical and similar elements, so that full reference is made to the above description.

[0047] A first significant difference is that in this embodiment ( Fig. 3 ) the rear axle HA is controlled axle by axle in the event that the redundant control unit 104 takes over control of the braking system 101. This means that in this embodiment ( Fig. 3 ) the rear axle redundancy brake pressure pRHA is not controlled in a wheel-specific manner, as in the first embodiment ( Fig. 2 ) is the case. Rather, the same redundancy brake pressure, namely the rear axle redundancy brake pressure pRHA, is supplied to the left and right rear wheels 5c, 5d and thus, in this embodiment, to the first and second spring-loaded actuators 12a, 12b. Nevertheless, even in this embodiment ( Fig. 3) redundant cabling to the rear axle wheel speed sensors 16a, 16b is provided, although this can also be optionally omitted. For example, it can be provided that the redundant control unit 104 receives the third and fourth wheel speed signals SW3, SW4 via the vehicle bus 120 and preferably determines a steering compensation to be controlled. The redundant control unit 104 can then transmit the determined steering compensation in the form of a steering angle or steering torque as a target value to the electronically controllable steering device 103, so that the latter can carry out the control of the transverse stabilizing steering interventions.

[0048] Furthermore, in contrast to the first embodiment ( Fig. 2 ) in the second embodiment ( Fig. 3 ) provides that in the case of redundancy the front axle VA can be controlled wheel by wheel. While in the first embodiment ( Fig. 2) an axle-by-axle control of the front axle VA in the case of redundancy was carried out by the redundant control unit 104, in the second embodiment ( Fig. 3 ) the front axle VA is braked wheel by wheel.

[0049] For this purpose, additional ABS valves are initially provided, namely a first redundancy ABS valve 30 and a second redundancy ABS valve 32. The first redundancy ABS valve 30 is connected between the first front axle ABS valve 26 and the first front axle brake actuator 3a. During normal operation, when the braking system 101 is controlled by the central control unit 102, the first redundancy ABS valve 30 is deactivated and controls the first front axle brake pressure pBVA1, output by the first front axle ABS valve 26, through and unchanged to the first front axle brake actuator 3a. The second redundancy ABS valve 32 is connected in a corresponding manner between the second front axle ABS valve 28 and the second front axle brake actuator 3b. This is also open during normal operation and allows the second front axle brake pressure pBVA2 to pass through.Both the first and second redundant ABS valves 30, 32 are connected to the redundant control unit 104 via first and second redundant ABS signal lines 134, 136. As in the first exemplary embodiment, the first and second front axle wheel speed sensors 14a, 14b are redundantly connected to the redundant control unit 104, so that the latter receives the first and second wheel speed signals SW1, SW2. In the second exemplary embodiment shown here (. Fig. 3) it is therefore possible that in the case of redundancy the front axle VA is controlled in a wheel-appropriate manner by the redundant control unit 104. While the front axle modulator 6 is again designed with two channels and provides the non-modulated front axle brake pressure pBVA on both the first channel 6.1 and the second channel 6.2 and in this case the first and second front axle ABS valves 26, 28 then openly control the front axle brake pressure pBVA, the first and second redundancy ABS valves 30, 32 can modulate this pressure in order to make the front axle redundancy brake pressure available in a wheel-appropriate manner as the first front axle redundancy brake pressure pRVA1 to the first front axle brake actuator 3a and the second front axle redundancy brake pressure pRVA2 to the second front axle brake actuator 3b.

[0050] While in the first embodiment ( Fig. 2) only the front axle VA is controlled axle by axle, while the rear axle HA is controlled wheel by wheel, in the second embodiment ( Fig. 3 ) only the rear axle (HA) is controlled axle by axle, while the front axle (VA) is controlled wheel-by-wheel. However, it should be understood that there can also be embodiments in which both the front axle (VA) and the rear axle (HA) are controlled axle by axle in the case of redundancy. In the event that further axles are provided, such as a second rear axle, a second front axle or an additional axle, these axles can also be controlled axle by axle in the case of redundancy. It is not necessary for all axles to be controlled axle by axle in the case of redundancy; rather, it is sufficient if only one of these axles is controlled axle by axle.

[0051] This is particularly true in Fig. 4 illustrated. Fig. 4shows a vehicle 200, namely a commercial vehicle 202, which includes a vehicle system 100 according to the invention, traveling around a curve. The curve profile of a target trajectory TSoll is shown illustratively, which here corresponds to a right-hand bend. A tolerance corridor TK is shown around the target trajectory TSoll. The vehicle 200 is to be kept within this tolerance corridor TK, even in the case of redundancy when transverse stabilizing steering interventions are carried out by means of the electronically controllable steering device 103. Both a front axle lateral guidance force FV and a rear axle lateral guidance force FH are shown on the vehicle 200. Since the vehicle 200 is in redundancy mode and the redundant electronic control unit 104 has taken over control, a front axle redundancy brake pressure pRVA is applied to the front axle VA and a rear axle redundancy brake pressure pRHA is applied to the rear axle HA.

[0052] If different cornering forces FV, ​​FH are determined, it is preferable to increase the brake pressure control of the front axle redundancy brake pressure pRVA or the rear axle redundancy brake pressure pRHA on the vehicle axle (front axle VA) and rear axle HA) where the higher cornering force FV, FH is applied. For example, if the front axle cornering force FV is greater than the rear axle cornering force FH, it is preferable to increase the brake pressure level of the front axle redundancy brake pressure pRVA. This can increase vehicle stability.

[0053] If an oversteering TO is detected during cornering along the target trajectory TSoll, it is preferable to increase the brake pressure control of the front axle redundancy brake pressure pRVA on the front axle VA and optionally on the trailer 204 (cf. Fig. 2). This results in more "pushing over the front axle" so that the oversteer TO can be overcome. At the same time, it is preferred that the electronically controllable steering device 103 is used to steer towards the outside of the curve in order to further reduce the oversteer TO. Usually, such interventions can be achieved in normal operation by adjusting the front axle brake pressure pBVA to the wheel. However, since in redundant operation according to the embodiment shown here ( Fig. 4 ) both the front axle VA and the rear axle HA are braked axle by axle, it is necessary in this case for the electronically controllable steering device 103 to carry out transverse stabilizing steering interventions, in this case steering in the direction of the outside of the curve, in order to keep the vehicle 200 on the target trajectory TSoll or within the tolerance corridor TK.

[0054] If, in contrast, understeering TU of the vehicle 200 is detected, the brake pressure control of the rear axle redundancy brake pressure pRHA on the rear axle HA is preferably increased. Optionally, the brake pressure control on a trailer 204 is also increased. This initially reduces the vehicle speed while simultaneously increasing traction on the front axle VA, so that the understeer can be recovered and the vehicle 200 can be kept on the target trajectory TSoll.

[0055] Fig. 5 now illustrates once again, purely schematically, a method 300 for decelerating and steering a vehicle 200, in particular a commercial vehicle 202, which comprises a vehicle system 100 according to one of the above-described preferred embodiments of a vehicle system 100 of the invention.

[0056] The method 300 begins with the step of determining 301 a failure of an electronic stability control system ESC1 (see Figures 2 and 3 ) of the electronically controllable pneumatic braking system 101. In response to this, as described above, a redundant and axle-by-axle control 302 of the front axle redundancy brake pressure pRVA or the rear axle redundancy brake pressure pRHA is carried out. At the same time, as required, transverse stabilizing steering interventions 304 are carried out, namely by means of the electronically controllable steering device 103, as described in particular above. As a result, the vehicle 200 is then intended to remain within the tolerance corridor TK (cf. Fig. 4 ) of the specified target trajectory TSoll.

[0057] In step 305, a check is then made to determine whether the vehicle 200 is still on the target trajectory TSoll. If this is the case, the program returns to step 305 and checks again whether the vehicle 200 is still on the target trajectory TSoll. If this is not the case, however, a check is made in step 306 to determine whether oversteering or understeering is present. If oversteering TO is detected, the brake pressure control of the front axle redundancy brake pressure pRVA of the front axle VA is increased, preferably in step 308, and at the same time the vehicle is steered towards the outside of the curve using the electronically controllable steering device 103. If understeering TU is detected, however, the brake pressure control of the rear axle redundancy brake pressure pRHA on the rear axle HA is increased, preferably in step 310. The method then returns to check whether the vehicle 200 is on the target trajectory TSoll or within the tolerance corridor TK. List of reference symbols (part of the description)

[0058] 2First brake circuit 3a, 3First and second front axle brake actuators 4Second brake circuit 5a, 5First and second front wheel 5c, 5First and second rear wheel 6Front axle modulator 6.1First front axle channel 6.2Second front axle channel 8a, 8First and second rear axle brake actuators 10Parking brake circuit 12a, 12First and second spring-loaded actuators 14a, 14First and second front axle wheel speed sensors 16a, 16First and second rear axle wheel speed sensors 20First compressed air supply 22Second compressed air supply 24Third compressed air supply 26First front axle ABS valve 28Second front axle ABS valve 30First redundant ABS valve 32Second Redundancy ABS valve 100Vehicle system 101Electronically controllable pneumatic braking system 102Central control unit 104Redundant control unit 106First voltage source 108Second voltage source 110Target trajectory control 112Unit for autonomous driving 114Secondary front axle brake control 116Secondary rear axle brake control 118SecondaryTrailer brake control 120 Vehicle bus 122 Second bus 124 Front axle signal line 126 First ABS signal line 128 Second ABS signal line 130 Pneumatic redundancy pressure line 132 Third bus 134 First redundancy ABS signal line 136 Second redundancy ABS signal line 200 Vehicle 202 Commercial vehicle 204 Trailer 300 Procedure 301-310 Steps 11 Parking brake module 103 Electronically controllable steering system ESC1 Electronic stability control ESC2 Redundant electronic stability control FH Front axle cornering force FV Rear axle cornering force HA Rear axle HA2 Further rear axle LWL Steering wheel angle LMSteering torque pBHA Rear axle brake pressure pBHA1 First rear axle brake pressure pBHA2 Second Rear axle brake pressure pBP Parking brake pressure pBVA Front axle brake pressure pBVA1 First front axle brake pressure pBVA2 Second front axle brake pressure pRHA Rear axle redundancy brake pressure pRVA Front axle redundancy brake pressure pRVA1 First front axle redundancy brake pressure pRVA2 Second front axle redundancy brake pressure TO OversteerTKTolerance corridor TSetpoint trajectory TUUndersteer SBRRedundant brake signals SERRedundant ESC signals SVBFront axle brake signal SW1First wheel speed signal SW2Second wheel speed signal SW3Third wheel speed signal SW4Fourth wheel speed signal VAFront axle WSetpoint Target value for transverse stabilizing steering interventions ZSetpoint Deceleration target value

Claims

1. Vehicle system (100) for a vehicle (200), in particular a commercial vehicle (202), comprising: an electronically controllable pneumatic brake system (101), and an electronically controllable steering device (103); wherein the electronically controllable pneumatic brake system (101) has 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 circuit (2, 4), and at least first and second front axle brake actuators (3a, 3b) for at least first and second front wheels (5a, 5b) on at least one front axle (VA), and at least first and second rear axle brake actuators (8a, 8b) for at least first and second rear wheels (5c, 5d) on at least one rear axle (HA), wherein the central control unit (102) has or is connected to an electronic stability control means (ESC1), which is designed for wheel-specific actuation of 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 (100) further comprises a redundant control unit (104) which, in the event of a failure of the electronic stability control means (ESC1) while the vehicle (200) is traveling, controls the first brake circuit (2) and / or the second brake circuit (4), characterized in that, in the event of failure of the electronic stability control means (ESC1) while the vehicle (200) is traveling, the redundant control unit (104) controls at least the front axle (VA) using a front axle redundancy brake pressure (pRVA) and / or the rear axle (HA) using a rear axle redundancy brake pressure (pRHA) on an axle-specific basis, and in that the electronically controllable steering device (103) performs transversely stabilizing steering interventions in order to keep the vehicle (200) within a tolerance corridor (TK) of a predetermined target trajectory (TSoll) of the vehicle (200), and wherein the electronically controllable steering device (103) is connected to the central control unit (102) in order to receive ESC signals (SE1) from the electronic stability control means (ESC1) or signals derived therefrom or processed thereby.

2. Vehicle system (100) according to claim 1, wherein the electronically controllable steering device (103) receives and regulates a steering wheel angle (LW) and / or a steering torque (LM) as a target value (WSoll) for the transversely stabilizing steering interventions.

3. Vehicle system (100) according to either of the preceding claims, comprising a redundant electronic stability control means (ESC2) which is connected to the redundant control unit (104) and provides redundant ESC signals (SER) thereto.

4. Vehicle system (100) according to claim 1 or 3, wherein the electronically controllable steering device (103) is connected to the redundant control unit (104) and / or the redundant electronic stability control means (ESC2) in order to receive redundant ESC signals (SER).

5. Vehicle system (100) according to any of the preceding claims, wherein the central control unit (102) is connected to a first voltage source (106) and the redundant control unit (104) is connected to a second voltage source (108) which is independent of the first voltage source (106).

6. Vehicle system (100) according to claim 5, wherein the electronically controllable steering device (103) or a part thereof is connected to the second voltage source (108).

7. Vehicle system (100) according to any of the preceding claims, wherein the redundant control unit (104) is connected to first and / or second wheel-speed sensors (14a, 14b, 16a, 16b) in order to receive wheel-speed signals (SW1, SW2, SW3, SW4).

8. Vehicle system (100) according to any of the preceding claims, further comprising a parking brake circuit (10) having a parking brake module (11) connected to the central control unit (102), and at least first and second spring-type actuators (12a, 12b) at least on the rear axle (HA) or a further rear axle (HA2), wherein the redundant control unit (104) forms an electronic control unit of the parking brake module (11) or is integrated therewith.

9. Vehicle system (100) according to any of the preceding claims, wherein, in the event of failure of the electronic stability control means (ESC1), during the axle-specific modulation of the front axle redundancy brake pressure (pRVA), the redundant control unit (104) provides the front axle redundancy brake pressure to the first and second front axle brake actuators (3a, 3b) in order to brake the front axle (VA) in an axle-specific manner.

10. Method (300) for decelerating and steering a vehicle (200), in particular a commercial vehicle (202), preferably comprising a vehicle system (100) according to any of the preceding claims, wherein the method comprises the steps of: - determining (301) a failure of an electronic stability control means (ESC1) of an electronically controllable pneumatic brake system (101); in response to determining the failure: - modulating (302), redundantly and axle-by-axle, a redundancy front axle brake pressure (pRVA) on at least one front axle (VA) and / or a redundancy rear axle brake pressure (pRHA) on at least one rear axle (HA) by means of a redundant control unit (104) of the electronically controllable pneumatic brake system (101), and - performing transverse stabilizing steering interventions (304) by 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), and further comprising the steps of: - determining oversteering (TO) of the vehicle (200); and in response thereto: - increasing a brake pressure modulation (pRVA, pRHA) of the redundancy front axle brake pressure (pRVA) on the front axle (VA) and optionally on a trailer (204); and - steering by means of the electronically controllable steering device (103) toward the outside of the curve or - determining understeering (TU) of the vehicle (200); and in response thereto: - increasing a brake pressure modulation (pRVA, pRHA) of the redundancy rear axle brake pressure (pRVA) on the rear axle (HA) and optionally on a trailer (204).

11. Method according to claim 10, comprising the steps of: - determining a front axle cornering force (FV) on the front axle (VA); - determining a rear axle cornering force (FH) on the rear axle (HA); wherein the redundant control unit (104) increases a brake pressure modulation (pRVA, pRHA) on the particular vehicle axle, of the front axle (VA) and rear axle (HA), on which the higher force, of the front axle cornering force (FV) and the rear axle cornering force (FH), is determined.

12. Vehicle (200), in particular a commercial vehicle (202), comprising a vehicle system (100) according to any of claims 1 to 9.