Steer-by-wire system for a motor vehicle, and method

Abstract

The invention relates to a steer-by-wire system (12) for a motor vehicle (10), comprising at least one steering-wheel actuator (14) having a first availability level (20) and comprising at least one wheel actuator (16) having a second availability level (22), wherein the steering-wheel actuator (14) communicates with the wheel actuator (16) via a communication interface (24, 26), characterized in that the first availability level (20) is lower than the second availability level (22), wherein a steering-angle sensor (18) having a third availability level (28) which is higher than the first availability level (20) is additionally designed to communicate with the wheel actuator (16) via the communication interface (24, 26). The invention also relates to a motor vehicle (10) and to a method.

Description

[0001] Steer-by-wire system for a motor vehicle and method

[0002] The invention relates to a steer-by-wire system for a motor vehicle according to the preamble of patent claim 1. Furthermore, the invention relates to a motor vehicle with a steer-by-wire system and a method for operating the steer-by-wire system.

[0003] Steer-by-wire systems are already known from the prior art. In particular, steering input is detected via a corresponding detection device on a steering wheel, and then an actuator converts an electrical signal from the steering system according to the detected steering input, thus implementing wired steering.

[0004] DE 102008 026 729 A1 describes an electromechanical steering system with a system for warning a driver of a steering malfunction, comprising means for detecting a malfunction, means for generating a steering wheel excitation, and control means which, upon detection of a malfunction, activate the means for generating a steering wheel excitation for a limited time interval to generate a tangible excitation of the steering wheel. Furthermore, a method for warning a driver of a malfunction of an electromechanical vehicle steering system is specified.

[0005] DE 102018 106 872 A1 relates to a steer-by-wire steering system for motor vehicles, comprising an electronically controlled steering actuator acting on the steered wheels as a function of a steering command, and a feedback actuator transmitting steering to a steering wheel in response to the road, wherein the feedback actuator and the steering actuator have their own power supply.

[0006] The object of the present invention is to provide a steer-by-wire system, a motor vehicle, and a method by means of which a steer-by-wire steering system of the motor vehicle can be implemented in a simple yet reliable manner. This object is achieved by a steer-by-wire system, a motor vehicle, and a method according to the independent patent claims. Advantageous embodiments are specified in the subclaims.

[0007] One aspect of the invention relates to a steer-by-wire system for a motor vehicle, comprising at least one steering wheel actuator with a first availability level and at least one wheel actuator with a second availability level, wherein the steering wheel actuator communicates with the wheel actuator via a communication interface.

[0008] It is provided that the first availability level is lower than the second availability level, wherein a steering angle sensor with a higher third availability level than the first availability level is additionally designed to communicate via the communication interface with the wheel actuator.

[0009] In particular, this allows the steering wheel actuator to have a lower availability level and thus be designed accordingly more simply. Should, for example, a communication problem arise, the steering angle sensor can transmit corresponding steering angle commands to the wheel actuator. This reduces the requirement for a higher availability level for the steering wheel actuator, allowing for a particularly simple design. One or more fieldbus systems or digital or analog sensor interface protocols can be used.

[0010] In particular, it is provided that the third availability level and the second availability level are of equal level. For example, the third availability level and the second availability level can correspond to an ASIL-D level. Furthermore, it can be provided that the first availability level corresponds to an ASIL-A level, an ASIL-B level, or an ASIL-C level. In particular, it is thus provided that the steering capability can still be reliably provided for steer-by-wire steering even when using components with, for example, a lower ASIL rating and lower individual failure safety. In particular, the steering angle sensor thus forms a redundant system for the steering wheel actuator. In particular, it is thus provided that, for example, additional hardware and redundant systems within the steering wheel actuator can be dispensed with, since the steering angle sensor is still available as a fallback level.By separating the handwheel actuator, or steering wheel actuator, from the steering angle sensor, a separate fallback level can be created in which the driver can control steering via the wheel actuator and only via the direct connection to the steering angle sensor. The corresponding redundant power supply of the steering wheel actuator and its classification as an ASIL-D component can thus be eliminated, or the steering wheel actuator can be designed to meet lower safety requirements. Failsafe properties of the steering wheel actuator can be supported by mechanical elements or specific electrical wiring of the steering wheel actuator.

[0011] Furthermore, it has proven advantageous if an electronic computing device is provided which controls communication between the steering wheel actuator and / or wheel actuator and / or steering angle sensor. In this case, it can be provided that the electronic computing device is designed to discontinue communication between the steering angle sensor and the wheel actuator in the event of a communication problem between the steering wheel actuator and the wheel actuator. In particular, it is thus provided that, should the electronic computing device determine, for example, that there is a communication problem between the steering wheel actuator and the wheel actuator, a communication level between the steering angle sensor and the wheel actuator can be provided as a fallback level. In particular, the electronic computing device can be connected to different communication interfaces of the motor vehicle in order to reliably receive or transmit corresponding control signals.and thus realize reliable steering of the steer-by-wire system.

[0012] It is also advantageous if two wheel actuators are provided, each connected to one or more wheels, wherein communication is provided between the steering wheel actuator and the two wheel actuators. In particular, two wheel actuators are thus provided, which are arranged, for example, on a respective front wheel of the motor vehicle. Based on an input at the steering wheel actuator, the first wheel actuator and the second wheel actuator can then be controlled accordingly. In particular, in the event of a communication problem, it is provided that the steering angle sensor is also in communication with the at least two wheel actuators and can thus transmit corresponding steering commands to the wheel actuators in the event of a steering wheel actuator failure. A further advantageous embodiment provides that the communication interface is designed as a CAN bus.Alternatively or additionally, the communication interface can be provided as an Ethernet interface. This makes it possible to rely on already reliable systems, including their capabilities for securing communication in the vehicle, and to implement appropriate communication protocols between the steering wheel actuator, the wheel actuator, and the steering angle sensor.

[0013] A further aspect of the invention relates to a motor vehicle with at least one steer-by-wire system according to the preceding aspect.

[0014] Yet another aspect of the invention relates to a method for operating a steer-by-wire system according to the preceding aspect, wherein, in the event of a communication problem between the steering wheel actuator and the wheel actuator, communication between the steering angle sensor and the wheel actuator remains.

[0015] In particular, the procedure is carried out using the steer-by-wire system.

[0016] Advantageous embodiments of the steer-by-wire system are to be regarded as advantageous embodiments of the motor vehicle and the method. The steer-by-wire system or the motor vehicle has the necessary features to enable the corresponding method steps to be carried out.

[0017] The electronic computing device comprises, for example, processors, circuits, in particular integrated circuits, as well as other electronic components in order to be able to carry out corresponding process steps.

[0018] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combination, but also in other combinations or on their own.

[0019] The invention will now be explained in more detail using a preferred embodiment and with reference to the drawings. In the drawings: Fig. 1 is a schematic side view of an embodiment of a

[0020] Motor vehicle with an embodiment of a steer-by-wire system; and

[0021] Fig. 2 is a schematic block diagram according to an embodiment of a

[0022] Steer-by-wire systems.

[0023] In the figures, identical or functionally identical elements are provided with the same reference numerals.

[0024] Fig. 1 shows a schematic side view of an embodiment of a motor vehicle 10. The motor vehicle 10 has a steer-by-wire system 12. The steer-by-wire system 12 in turn has a steering wheel actuator 14, at least one wheel actuator 16, and a steering angle sensor 18. In particular, the steering wheel actuator 14 is coupled, for example, to a steering wheel 20, on which a person, for example a driver of the motor vehicle 10, can make a corresponding steering input. In particular, in the steer-by-wire system 12, no mechanical connection is provided between the steering wheel 20 and the wheel actuator 16. In particular, a wired communication takes place between the steering wheel actuator 14 and the at least one wheel actuator 16.

[0025] Fig. 2 shows a schematic block diagram according to an embodiment of the steer-by-wire system 12. In particular, Fig. 2 shows that the steer-by-wire system 12 has at least the steering wheel actuator 14 with a first availability level 20 and the wheel actuator 16 with a second availability level 22. The steering wheel actuator 14 is coupled to the wheel actuator 16 via a communication interface 24, 26. It is provided that the first availability level 20 is lower than the second availability level 22, wherein the steering angle sensor 18 has a higher third availability level 28 than the first availability level 20 and is additionally designed to communicate with the wheel actuator 16 via the communication interface 24, 26. In particular, it is shown here that a first communication interface 24 and a second communication interface 26 are provided.For example, the first communication interface 24 is an Ethernet interface, and the second communication interface 26 is a CAN bus interface. Alternatively or additionally, the first communication interface 24 may also be configured as a CAN bus interface, or the second communication interface 26 may be configured as an Ethernet interface. In the following exemplary embodiment, the steering angle sensor 18 is supplied with a corresponding voltage from the steering wheel actuator 14 via a supply line 30.

[0026] The steering wheel actuator 14, in turn, has a first machine 32, which is coupled to another first machine 34 of the wheel actuator 16 via the first communication interface 24. Furthermore, another second machine 36 is coupled to the first machine 32 and the steering angle sensor 18 via the second communication interface 26.

[0027] In particular, it is intended that the third availability level 28 and the second availability level 22 be of the same level, for example, both correspond to an ASIL D level. The first availability level 20 can, for example, correspond to an ASIL A level or an ASIL B level.

[0028] Furthermore, Fig. 2 shows that an electronic computing device 38 is provided, which controls communication between the steering wheel actuator 14 and / or the wheel actuator 16 and / or the steering angle sensor 18. The electronic computing device 38 can be configured to suspend communication between the steering angle sensor 18 and the wheel actuator 16 in the event of a communication problem between the steering wheel actuator 14 and the wheel actuator 16.

[0029] Furthermore, it can be provided that at least a first wheel actuator 16 is provided on a first wheel of the motor vehicle 10 and a second wheel actuator is provided on a second wheel of the motor vehicle 10, wherein communication is provided between the steering wheel actuator 14 and the two wheel actuators 16.

[0030] In particular, it is thus provided that by separating the steering wheel actuator 14 from the steering angle sensor 18, an independent fallback level can be created in which the driver can only achieve steering capability via the wheel actuator 16 via the direct connection to the steering angle sensor 18. The redundant power supply of the steering wheel actuator 14 and its classification as an ASIL-D component can be eliminated, or the steering wheel actuator 14 can be designed with a lower safety requirement.

[0031] Motor vehicle

[0032] Stee r- By- Wi re- Syste m

[0033] steering wheel actuator

[0034] Wheel actuator

[0035] Steering angle sensor first availability level second availability level first communication interface second communication interface third availability level

[0036] Supply line first machine further first machine further second machine electronic computing device

Claims

Patent claims 1. Steer-by-wire system (12) for a motor vehicle (10), with at least one steering wheel actuator (14) with a first availability level (20) and with at least one wheel actuator (16) with a second availability level (22), wherein the steering wheel actuator (14) communicates with the wheel actuator (16) via a communication interface (24, 26), characterized in that the first availability level (20) is lower than the second availability level (22), wherein a steering angle sensor (18) with a higher third availability level (28) than the first availability level (20) is additionally designed to communicate with the wheel actuator (16) via the communication interface (24, 26).

2. Steer-by-wire system (12) according to claim 1, characterized in that the third availability level (28) and the second availability level (22) are of the same level.

3. Steer-by-wire system (12) according to claim 1 or 2, characterized in that the third availability level (28) and the second availability level (22) correspond to an ASIL-D level.

4. Steer-by-wire system (12) according to one of the preceding claims, characterized in that the first availability level (20) corresponds to an ASIL-A level or an ASIL-B or ASIL-C level.

5. Steer-by-wire system (12) according to one of the preceding claims, characterized in that an electronic computing device (38) is provided which controls communication between the steering wheel actuator (14) and / or the wheel actuator (16) and / or the steering angle sensor (18).

6. Steer-by-wire system (10) according to claim 5, characterized in that the electronic computing device (38) is designed to stop communication between the steering angle sensor (18) and the wheel actuator (16) in the event of a communication problem between the steering wheel actuator (14) and the wheel actuator (16).

7. Steer-by-wire system (10) according to one of the preceding claims, characterized in that at least a first wheel actuator (16) is provided on a first wheel of the motor vehicle (10) and a second wheel actuator is provided on a second wheel of the motor vehicle (10), wherein communication is provided between the steering wheel actuator (14) and the two wheel actuators (16).

8. Steer-by-wire system (10) according to one of the preceding claims, characterized in that the communication interface (24, 26) is designed as a fieldbus system.

9. Motor vehicle (10) with at least one steer-by-wire system (12) according to one of claims 1 to 8.

10. A method for operating a steer-by-wire system (12) according to one of claims 1 to 8, wherein in the event of a communication problem between the steering wheel actuator (14) and the wheel actuator (16) and communication between the steering angle sensor (18) and the wheel actuator (16) is discontinued.

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