Steer-by-Wire-Lenksystem

Abstract

The invention relates to a steer-by-wire steering system (1) of a motor vehicle (2) comprising a control unit (4) for acquiring and / or providing a steering command and a road wheel actuator (6) for mechanically implementing the steering command at at least one vehicle wheel (7) of the motor vehicle (2), wherein the control unit (4) comprises a force feedback actuator (41) having at least one energizable brake (107a) with a magnetic field generating device (117a) which has at least one first energizable excitation coil (120a), wherein the magnetic field of the first excitation coil (120a) in the energized coil state acts on a steering shaft (43) of the control unit (4) such that the latter can be subjected to a braking torque, wherein the control unit (4) has an associated first control unit (5a) and the road wheel actuator (6) has an associated second control unit (5b),wherein at least the first excitation coil (120a) can be energized with the first control unit (5a) of the operating unit (4) and / or with the second control unit (5b) associated with the roadwheel actuator (6), wherein the first energizable brake (107a) and / or the second energizable brake (107b) are directly connected to the second control unit (5b) of the roadwheel actuator (6).

Description

The present invention relates to a steer-by-wire steering system of a motor vehicle comprising a control unit for acquiring and / or providing a steering command and a roadwheel actuator for the mechanical implementation of the steering command at at least one wheel of the motor vehicle, wherein the control unit comprises a force-feedback actuator having at least one energizable brake with a magnetic field generating device which has at least one first energizable excitation coil, wherein the magnetic field of the first excitation coil in the energized coil state acts on a steering shaft of the control unit in such a way that the latter can be subjected to a braking torque, wherein the control unit has an associated first control unit and the roadwheel actuator has an associated second control unit. In today's automotive industry, the ongoing development of new technologies is crucial for improving vehicle performance, safety, and driver comfort. One area that has garnered significant attention is steering technology. In particular, steer-by-wire systems, which replace mechanical steering columns with electrical signaling systems, offer numerous advantages over traditional steering systems. These systems allow for more flexible design, reduced vehicle weight, and improved driving dynamics. A steer-by-wire steering system for motor vehicles eliminates the mechanical connection between the steering wheel and the wheels by transmitting the driver's steering movements through electronic control units and actuators.A key advantage of this technology is the ability to dynamically adjust the steering characteristics, optimizing both driving stability and maneuverability at varying speeds and on different road surfaces. Furthermore, the absence of mechanical linkages opens up more scope for innovative vehicle designs and enhanced safety features. Manufacturers can thus position the steering wheel anywhere in the interior or develop entirely new vehicle concepts without a traditional steering wheel. These systems not only increase comfort and the driving experience but also contribute to the integration of autonomous driving functions. Improvements to feedback mechanisms and control algorithms ensure that the driver retains control of the vehicle at all times, while simultaneously laying the foundation for future developments in automated driving.As such, the steer-by-wire steering system represents a significant development in vehicle steering technology, which has the potential to fundamentally change the way vehicles are designed and operated. In steer-by-wire systems, which are subject to particularly high safety requirements, the problem persists that many known designs have only limited or no redundancy. If, for example, a central control module or the main actuator fails, this can lead to a complete loss of steering capability, which entails significant safety risks. While solutions exist in which certain components are provided as duplicates, this regularly increases the required installation space and integration complexity. Furthermore, the use of high-performance electronic components and powerful drive units often makes a compact design difficult.High currents, sophisticated control algorithms and comprehensive heat dissipation measures not only cause more hardware costs, but can also lead to increased electromagnetic interference, which in turn brings additional requirements for EMC compatibility. Furthermore, in many conventional steer-by-wire systems, key driver assistance parameters, such as the feedback torque acting on the steering shaft, can only be adapted to highly variable driving and environmental conditions to a limited extent. While fundamental parameters like torque build-up or damping can be influenced via software, this is often limited by the use of only a single actuator unit or by insufficient control accuracy. Particularly in highly dynamic driving situations such as rapid evasive maneuvers, emergency braking, or during partially and fully automated driving functions, many established steer-by-wire concepts reach their limits. However, it is precisely in these situations that a reliable, redundant, and simultaneously highly flexible control of the steering feel is essential to ensure stable driving behavior even in the event of a malfunction. DE 10 2022 125 767 A1 discloses a vehicle component based on the steer-by-wire concept, comprising at least one movable steering unit, an actuator for generating a torque acting on the steering unit, and a control unit for controlling the actuator. Furthermore, a diagnostic device is described that detects a fault in which the actuator provides an impermissible torque, and a fault protection device controllable by the diagnostic device, which, upon detection of the fault, acts on the steering unit so that it cannot be moved without resistance.The fault protection system includes at least one fault braking device which cancels its braking effect when a defined energy supply is present and provides its fault braking torque when the defined energy supply is lost, as well as an interruption device controllable by the diagnostic device, by which the energy supply of the fault braking device is interrupted into a fault mode. The object of the invention is therefore to avoid or at least reduce the problems known from the prior art and to provide an optimized steer-by-wire steering system for a motor vehicle. This problem is solved by a steer-by-wire steering system for a motor vehicle comprising a control unit for acquiring and / or providing a steering command and a roadwheel actuator for mechanically implementing the steering command at at least one wheel of the motor vehicle, wherein the control unit comprises a force-feedback actuator, having at least one energizable brake with a magnetic field generating device, which has at least one first energizable excitation coil, wherein the magnetic field of the first excitation coil, in the energized coil state, acts on a steering shaft of the control unit such that the latter can be subjected to a braking torque, wherein the control unit has an associated first control unit and the roadwheel actuator has an associated second control unit, wherein the at least first excitation coil is connected to the first control unit of the control unit and / or to the second,The control unit associated with the roadwheel actuator can be powered. This achieves the advantage that both the control unit and the roadwheel actuator are able to selectively power the excitation coil. This allows for a flexible allocation of control and safety functions: If one control unit fails, the other can continue to generate the required braking torque. This increases the overall reliability of the system, which is particularly advantageous in safety-critical applications. First, the individual elements or assemblies of the steer-by-wire steering system are discussed, and subsequently, particularly preferred embodiments are listed. Steer-by-wire steering system For the purposes of this patent application, a steer-by-wire steering system is a motor vehicle steering system that eliminates the need for a mechanical connection between a control unit and a steering mechanism for positioning the vehicle's wheels. Instead, it transmits steering movements and commands electronically, enabling precise and flexible vehicle control. A steer-by-wire steering system offers significant advantages over conventional steering systems in terms of weight savings, design freedom, and driving comfort. In particular, the elimination of the steering column and mechanical assemblies reduces the vehicle's weight and complexity, while allowing for a more flexible interior design. The function of a steer-by-wire steering system includes, for example, converting steering wheel movements into electronic signals that are sent to a control unit. This control unit analyzes the inputs and controls one or more steering actuators of a roadwheel actuator to bring the wheels to the required steering angle. This improves adaptability to different driving situations and allows for the easy integration of additional functions such as lane keeping assist or automated driving. motor vehicle For the purposes of this patent application, a motor vehicle is a motorized land vehicle designed for the transport of persons or goods, particularly on roads. It includes all types of vehicles powered by an engine, including but not limited to cars, trucks, buses, and motorcycles. A motor vehicle may incorporate different drive systems, such as internal combustion engines, electric motors, or hybrid systems. Front axle steering For the purposes of this application, front axle steering is a motor vehicle assembly designed to control the direction of the front wheels in order to ensure vehicle steering in accordance with the instructions of a driver and / or a control program. Preferably, a steer-by-wire steering system is designed for front axle steering. Control unit For the purposes of this patent application, a control unit is a device for controlling the driving direction of a motor vehicle by a user, and is used in particular in a steer-by-wire system. This control unit serves to translate the driver's steering movements into electronic signals, which are used to control the actual steering movements of the vehicle wheels. A key function of the control unit is to provide the driver with a realistic steering feel that comes as close as possible to that of a mechanical steering unit, in order to enable intuitive and safe vehicle control. To this end, the control unit is able to provide a variable resistance torque at the steering shaft, which generates haptic feedback and can be adapted to the driving situation. Force feedback actuator In connection with this invention, a force feedback actuator is a device designed to transmit tactile and / or haptic feedback to the driver by transmitting forces to the steering element in contact with the driver. This feedback simulates the feeling of a mechanical or hydraulic steering force transmission present in conventional steering systems. The force feedback actuator operates by generating forces based on electronic control commands that reflect the current driving situation and road conditions to provide the driver with a realistic steering feel. The force feedback actuator can use various components or assemblies, such as electric motors, brakes, magnetic coils, or other suitable means, to generate the required forces. A force feedback actuator can operate both actively (e.g., motor-driven) and passively (e.g., regeneratively). In active mode, the force feedback actuator is driven by an external energy source, such as an electric motor, which applies force to the steering mechanism to generate haptic feedback. This means the actuator is controlled to provide the user with perceptible feedback, simulating realistic forces when using input devices in vehicle steering systems. In passive mode, however, the force feedback actuator operates regeneratively, converting and reusing kinetic energy from the movement of the steering mechanism or other user interaction. In this mode, an external drive is not necessarily required; instead, the mechanical energy supplied by the steering mechanism is used to generate resistance or damping.This mode is used particularly for increasing efficiency and saving energy, as it utilizes regenerative forces and additionally offers authentic haptic feedback. The ability to operate the force feedback actuator in both motor and generator modes allows for flexible and efficient fulfillment of diverse haptic feedback requirements, with the switch between the two operating modes occurring dynamically depending on the need, load condition, or application. A force feedback actuator preferably comprises an electric motor. A gearless electric motor is particularly preferred. Furthermore, the force feedback actuator can include a brake. The force feedback actuator particularly preferably comprises an electric motor and a brake, especially preferably an energizable brake. Electric motor For the purposes of this patent application, an electric motor is an electric machine which, in conjunction with the force-feedback actuator within the control unit of a steer-by-wire system, serves to apply targeted torques to the steering shaft in order to provide the driver with haptic feedback about the driving situation or defined steering resistances. The electric motor can be actively controlled to generate a controlled steering feel by generating specific resistances or supporting torques depending on driving parameters, road conditions, or driver assistance systems. The motor assembly comprises a stator and rotor, with the rotor preferably coupled directly or via a gearbox to the steering shaft, so that torque can be transmitted to the steering shaft by selectively controlling the motor current. The electric motor can be designed as a radial flux machine or as an axial flux machine. The electric motor can be coupled to a gearbox or operated without one. A gearbox allows the torque and speed to be adapted to the specific requirements of the control unit. Advantageously, a planetary gearbox or a harmonic drive can be used to achieve precise torque transmission with high efficiency and low backlash. A gearbox connection can be particularly advantageous when a compact, higher-speed motor is used and the torque needs to be reduced to a level suitable for the force feedback system. Alternatively, the motor can be operated without a gearbox if direct torque transmission to the steering shaft is required. The electric motor can have a redundant, energizable motor winding. brake For the purposes of this patent application, a brake is a device within the control unit of a steer-by-wire system that selectively exerts a controlled braking effect on the steering shaft in order to influence, limit, or dampen its movement. The brake can, in particular, serve to provide a defined resistance force against a rotational movement of the steering shaft in order to create an authentic steering feel for the driver or to implement safety-critical limits on steering movement. The brake can alternatively or additionally be preferably electromagnetically or electromechanically designed, so that its braking force can be actively controlled by a control unit. In a preferred embodiment, the brake comprises an electrically energized braking component that exerts a friction-based, magnetic, or fluidic braking effect on a component connected to the steering shaft. The braking force can be dynamically adjusted depending on various operating parameters, such as vehicle speed, steering angle, or driving situation. It is particularly preferred that the brake is designed as a magnetorheological brake, either alternatively or additionally. The brake can also be designed mechanically as a friction brake, either alternatively or additionally, in which a brake pad is pressed against a braking surface coupled to the steering shaft, thereby achieving torque-dependent deceleration of the steering shaft. In a further advantageous embodiment, the brake can be designed as an eddy current brake, either additionally or alternatively, in which a magnetic field is generated that exerts a braking effect on a conductive disc through induction. This enables wear-free and virtually noiseless braking. Alternatively or additionally, the brake can also be designed as an electromechanical clamping device, in which an electromechanically or magnetically actuated clamping element selectively inhibits or completely blocks the rotational movement of the steering shaft. Advantageously, a gearbox, such as a planetary gearbox, can also be considered an alternative or supplementary brake within the meaning of this patent application. Due to its internal friction, a gearbox can exert a braking effect on the steering shaft by inhibiting or slowing down rotational movements. In particular, a gearbox configuration with a specifically adapted gear ratio and friction properties can be used to provide a metered braking force without requiring additional active braking components, or to support them, for example, by providing a certain base frictional torque. Such a gearbox can be integrated into the overall system to dampen the steering movement or to provide a specific resistance profile that serves to simulate a conventional mechanical steering system. A preferred integration of the brake within the telescopic slide ensures a compact design and optimized mass distribution. The brake can be positioned between the steering angle limiter and the electric motor, thus performing a synergistic function within the overall steering resistance and feedback system. The brake can be designed to either continuously provide an adjustable braking force or be actively engaged in defined operating conditions, for example, to limit the maximum steering angle or to generate specific haptic feedback. In a particularly preferred embodiment, the brake can be coupled to the electric motor, allowing both components to work together to enable finely graduated control of the steering feel. magnetorheological braking device For the purposes of this patent application, a magnetorheological braking device is a device that uses a magnetorheological medium to generate a variably controllable braking torque between a rotor and a stator. A magnetorheological medium preferably comprises a liquid or gaseous carrier fluid in which magnetizable particles are dispersed. When a magnetic field is applied, these particles align themselves along the magnetic field lines, thereby increasing the viscosity of the medium and significantly enhancing its shear strength. This enables precise control of the braking force by regulating the intensity of the magnetic field. The magnetorheological braking device is preferably designed such that a rotatably mounted shaft is guided through the rotor, which is arranged concentrically around the shaft. The rotor is preferably made of sheet metal. The rotor is preferably housed together with a stator in a casing that forms a receiving chamber for the magnetorheological medium. The stator is equipped with a magnetic coil which, when energized, generates a magnetic field that influences the magnetorheological medium in the receiving chamber.The magnetic field is controlled to generate a variable braking force between the rotor and the stator by increasing the shear strength of the medium when the magnetic field is activated. Preferably, the magnetorheological brake is equipped with a seal to prevent the medium from escaping the brake housing and simultaneously protect the internal components of the brake from contamination. It can also be advantageous to use multiple magnetorheological braking devices to achieve a higher overall braking torque. This configuration also allows the braking force to be distributed across multiple axes or components of the control unit, thereby improving the system's flexibility and adaptability. Using multiple braking devices simultaneously enables more precise control of the braking effect, as each unit can be controlled independently. This can be particularly beneficial in more complex systems or applications where different braking torques are required at various points. Furthermore, the redundancy of multiple braking devices can increase operational reliability, as the failure of one unit ensures that the others remain functional. Dividing the brake into several individual braking units can also contribute to each individual braking section having lower inductance. Lower inductance results in shorter coil response times, as changes in current supply can be implemented more quickly. This optimizes the brake's dynamic response. A more dynamic response means the brake can react more rapidly to varying operating conditions, which is particularly advantageous in applications with rapidly changing load requirements. It is also conceivable that a magnetorheological brake could have two spatially separated excitation coils. This configuration allows for more targeted and flexible control of the magnetic field by generating different magnetic field strengths in various regions of the magnetorheological medium. The spatial separation of the excitation coils makes it possible to generate separate magnetic fields that can act on specific particle concentrations or movements within the medium. This offers the advantage that the braking force can be individually adapted to the requirements of different operating conditions. Furthermore, this arrangement allows for a more even distribution of heat generation, which can lead to improved thermal stability of the braking device. Here, too, the second excitation coil can provide redundancy, ensuring that if one excitation coil fails, the other remains operational. The excitation coils can preferably be connected in parallel. Using a parallel connection of coils within the magnetorheological braking device can offer significant advantages, particularly regarding the dynamic response and compensability of the brake. Connecting the inductors in parallel increases the overall capacitance of the magnetic field. This results in a faster system response time, as the magnetorheological media can react more quickly to changes in the magnetic field. The dynamic response of the brake is thus improved, as it allows for a more precise and immediate adjustment of the braking force to changing operating conditions. A further advantage of the parallel connection is the improved compensability of the system.If one coil in the parallel circuit malfunctions or does not operate optimally, the remaining coils can still effectively contribute to generating the required magnetic field. This ensures increased reliability and fail-safe operation of the braking system. brake rotor For the purposes of this patent application, a brake rotor of a magnetorheological brake is the rotating element directly connected to the rotor shaft and functioning as the active braking element within the system. The brake rotor interacts directly with the magnetorheological medium located between it and the brake stator. The function of the brake rotor is to translate a change in the viscosity of the magnetorheological medium into the desired braking pressure through its rotation in the magnetic field. This allows the braking torque on the shaft to be adjusted and controlled, enabling precise regulation of the braking effect within the overall steering system. Preferably, the brake rotor can be designed as a laminated brake rotor. brake stator For the purposes of this patent application, a brake stator is a component of a magnetorheological brake that is fixed against rotation relative to the brake housing. It represents the stationary part of the brake and can advantageously be designed as a cylindrical sleeve. The brake stator is designed to accommodate the brake rotor and, together with the rotor and the brake housing, to form the magnetorheological media chamber containing the magnetorheological medium. Preferably, the brake stator is designed to have an inner surface along which the rotor can move, forming a defined effective gap. The function of the brake stator is to absorb the braking torques transmitted from the brake rotor via the medium, thereby ensuring reliable frictional engagement in the steering system. The brake stator of the magnetorheological braking device is advantageously constructed in multiple parts and preferably comprises a winding carrier, a locking ring, and an outer tube. These components are preferably formed from sheet metal using a forming process. The aforementioned components are preferably connected to one another by means of formed joints, which enables the formation of flat, pressed contacts between the stator components. This results in low magnetic resistance within the assembly, thereby significantly improving the efficiency of the magnetic circuit. The reduced magnetic resistance contributes to achieving a higher braking torque without requiring an increased coil current. This increases the energy efficiency of the braking device and allows for a more compact and cost-effective design of the electrical components. Magnetic field generating device For the purposes of this patent application, a magnetic field generating device is a device that generates or influences an electromagnetic field within the magnetorheological brake in order to selectively control the flow properties of the magnetorheological medium. The magnetic field thus generated penetrates the medium space formed between the brake rotor and the brake stator and causes a change in the rheological properties of the medium, so that its shear viscosity can be increased and a corresponding braking torque can be generated. Preferably, the magnetic field generating device can be designed as an electromagnet capable of being powered, wherein a winding is arranged on a ferromagnetic core and the magnetic field lines are selectively guided into the working space by suitable shaping.Advantages arise from the ability to continuously control the braking torque depending on the applied current, allowing for precise and rapid adaptation to different driving situations in the steer-by-wire system. The magnetic field generation unit is advantageously integrated within the brake housing or in the area of ​​the brake stator to achieve short magnetic flux paths and efficient field coupling with the medium. Alternatively, permanent magnetic field sources can be used instead of or in addition to an electromagnet if a base magnetic field is required or if fail-safe protection is necessary. To generate the braking effect, the magnetic field generation device can be designed to be controllable, so that it can generate a magnetic field with a predetermined field strength and / or magnetic flux when appropriately controlled. In particular, the magnetic field generation device can be configured to adjust the field strength and / or magnetic flux of this magnetic field between zero and the predetermined maximum strength. In this way, the generated braking effect is also controllable. For this purpose, the magnetic field generation device can be designed as a coil whose magnetic field depends on the electric current flowing through the coil's windings.By adjusting the electric current, the field strength and / or the magnetic flux of the magnetic field can be set between zero and a predetermined maximum field strength and / or a predetermined maximum magnetic flux, and thus the braking effect can also be adjusted. The magnetic field generation device is preferably arranged in the brake stator of the magnetorheological brake. Excitation coil For the purposes of this patent application, an excitation coil is a winding made of electrically conductive material that generates a magnetic field when energized. When an electric current is applied, a magnetic flux density is built up, which preferably serves to generate torque or braking effect in a force-feedback actuator or a braking device. Advantageously, the conductor is wound in multiple layers onto a coil former to achieve a compact design at high current density. Preferably, the conductor consists of a thermally resilient and electrically conductive wire, for example, made of copper, which is provided with an insulating layer. The excitation coil can advantageously be integrated into a U-shaped coil carrier, resulting in a defined magnetic circuit without shunts through the coil carrier. This allows the field lines to be precisely aligned with the stator, rotor, or magnetically reactive medium to be influenced. In this way, the desired braking effect can be strongly and precisely regulated, as the strength of the magnetic field can be directly controlled by the applied current and adapted to different operating conditions. Coil carrier For the purposes of this patent application, a coil carrier is a structural unit that serves to accommodate and fix at least one excitation coil in a defined position in order to ensure precise alignment and optimal magnetic coupling with adjacent components. Furthermore, the coil carrier enables simplified assembly and manufacturing by guiding the excitation coil within a clearly structured housing or frame construction, thereby reducing assembly effort and the number of components. Preferably, it consists of a dimensionally stable material that withstands the thermal and mechanical stresses during operation and ensures high dimensional accuracy. Coil carriers are typically made of non-magnetic or weakly magnetizable materials such as stainless steel or plastics. Advantageously, the coil carrier has a U-shaped cross-sectional profile in the circumferential direction, at least in sections, with the legs of this profile designed to securely hold the coil and minimize vibrations. Furthermore, this design allows for orderly routing of electrical conductors, enabling them to be reliably led out of the coil space, while simultaneously ensuring targeted guidance of the magnetic flux in the areas relevant for generating braking torque. magnetorheological medium For the purposes of this patent application, a magnetorheological medium is a substance that changes its rheological properties, in particular its viscosity and flowability, depending on an applied magnetic field. It comprises, for example, a liquid or gaseous carrier fluid in which magnetizable particles are finely dispersed. These particles are advantageously spherical and possess a magnetic permeability that enables them to react to magnetic fields. The carrier fluid, which preferably consists of an oil or another suitable liquid medium, or alternatively of a gas such as air, ensures a homogeneous suspension of the particles and facilitates their movement in the absence of a magnetic field. In the described invention, the magnetorheological medium fulfills the function of enabling the controllable transfer of mechanical energy.When a magnetic field is applied, the magnetizable particles align themselves along the field lines, forming chain-like structures. This structuring significantly increases the flow resistance in the medium and allows for precise control of torque transmission between the rotor and stator. The strength of this torque transmission can be regulated by the intensity of the applied magnetic field, enabling precise and dynamic adjustment of the braking characteristics. The particle concentration in the carrier fluid is preferably in the range of 20 to 50 volume percent. A concentration of approximately 30 to 40 volume percent is particularly advantageous, as it offers an optimal balance between maximizing the magnetorheological effect and minimizing viscosity when the magnetic field is deactivated. This concentration allows for precise control of the rheological properties while simultaneously ensuring good pumpability and handling of the medium within the system. Magnetorheological particles For the purposes of this patent application, a magnetorheological particle is a magnetizable or magnetically reactive particle suspended in a carrier fluid that, when exposed to a magnetic field, causes a targeted change in the fluid's flow properties. Preferably, these particles consist of iron or iron alloys and possess high permeability, enabling them to form chain structures very quickly when a magnetic field is applied, thereby increasing the viscosity or flow resistance of the magnetorheological medium. In this way, the particles cause a rapid and controllable increase in the shear forces between the rotor and stator, which is advantageously used to control the braking effect.The ability to quickly and reversibly adjust their orientation in the magnetic field enables very precise and dynamic control of the braking characteristics, as the shear strength in the medium can be influenced virtually without delay. The particles are preferably coated to minimize agglomeration and sedimentation, thus maintaining uniform distribution in the carrier medium even during prolonged operation. The carrier fluid is advantageously selected to exhibit both high thermal stability and low aging to ensure the medium's performance under varying thermal and mechanical conditions. The magnetizable particles of the magnetorheological medium are preferably made of ferromagnetic or superparamagnetic materials. Suitable materials include, for example, iron, nickel, cobalt, their alloys, or ferritic compounds such as iron oxide (Fe3O4). These materials are characterized by their high magnetic permeability and saturation magnetization, enabling an efficient response to an applied magnetic field. The particle size is preferably in the range of 0.1 micrometers to 10 micrometers, with a range of 1 micrometer to 5 micrometers being particularly advantageous. This size distribution ensures stable suspension in the carrier fluid and minimizes sedimentation, while simultaneously guaranteeing rapid and efficient structuring of the particles when a magnetic field is applied. brake housing For the purposes of this patent application, a brake housing of a magnetorheological brake is the structural element that serves as the outer enclosure of the brake and encloses the receiving space for the magnetorheological medium (magnetorheological media chamber). The brake housing thus has, in particular, the function of securely containing the magnetorheological medium and enabling the interaction of the magnetorheological medium between the brake rotor and the brake stator within the brake. Since the brake housing forms a "frame structure," it not only protects the internal components from external influences but can also serve as a basis for the correct alignment of all internal parts. The brake housing can be made from various materials, with metal alloys, plastics or composite materials being preferred. A brake housing can be manufactured as a single piece or in multiple pieces. One-piece housings offer high structural integrity and reduce potential weak points that could arise from joints. Multi-piece housings, on the other hand, can support a more modular design, allowing for more flexible maintenance and easier replacement of individual components. In principle, it is also conceivable that the stator functions at least partially or even completely as a brake housing or part thereof. steering shaft For the purposes of this patent application, a steering shaft is a mechanical component that serves as a pivot axis for transmitting torques and / or rotational movements in a control unit of a steer-by-wire steering system. The steering shaft is designed to be rotatably mounted about a defined axis and provides a mechanical connection to the steering element of the control unit, for example, a steering wheel or a joystick. Functionally, the steering shaft thus performs, in particular, the task of transmitting a rotational movement caused by the steering element to subsequent mechanical or electronic elements of the control unit of the steer-by-wire system. The steering shaft can be either a single piece or a multi-piece design. A single-piece design offers the advantage of high structural integrity and particularly precise torque transmission, as there are no additional connection points. A multi-piece steering shaft, on the other hand, allows for a modular design in which different segments can be specifically tailored to different requirements. In a multi-piece design, joint or coupling elements can also be integrated to create a flexible connection between the individual segments and, for example, compensate for existing tolerances. This configuration also facilitates the replacement of individual sections in the event of maintenance or repair and allows for better adaptation to complex installation space requirements. Advantageously, the steering shaft is thus mounted in a rotation angle limiter, which mechanically limits the rotational movement of the steering shaft. The brake rotor is preferably connected to the steering shaft in a rotationally fixed manner. control unit For the purposes of this patent application, a control unit is an electronic module configured for acquiring, processing, and / or outputting control signals. It is preferably equipped with suitable hardware and software to, in particular, evaluate sensor data, send commands to actuators, and monitor the operating status of components. Preferably, a microprocessor or microcontroller is used for this purpose, which, in conjunction with memory modules and power electronics modules, enables reliable, fast, and precise control. Advantageously, the control unit can be integrated into the overall vehicle, thereby enabling coordinated interaction with other systems. The design of the control unit preferably also includes communication interfaces to higher-level control systems, thus ensuring robust transmission of both control commands and diagnostic data. The control unit, in conjunction with the operating unit, is advantageously designed as a microcontroller- or microprocessor-based computing unit equipped with appropriate peripheral components for acquiring, processing, and converting control signals. It preferably receives continuous data from sensors that detect parameters such as steering angle, steering torque, speed, or driving conditions, and, based on this information, calculates the required electrical current to the motor as well as the required braking force to optimize torque smoothing. It preferably features high-resolution current control to precisely compensate for even the smallest torque ripples of the electric motor. To implement the control commands, the control unit advantageously includes power electronics, for example in the form of pulse-width modulation (PWM) controlled output stages for controlling the electric motor, as well as a separate control circuit for the brake. The brake control ensures precise control of the frictional torques acting on the steering shaft, so that the steering feel perceived by the driver is free from disruptive vibrations or sudden load changes. The control algorithms within the control unit preferably include model-based control methods that enable both adaptive torque correction and a learning-based adjustment of the steering feel to the individual driving style or the current driving situation. The control unit is preferably connected to the higher-level vehicle control system via a communication interface to incorporate additional parameters such as vehicle speed, driving mode, or road conditions into the control process. Advantageously, this communication takes place via a CAN or FlexRay bus to ensure robust and low-latency signal transmission. Furthermore, the control unit can be equipped with a diagnostic and self-monitoring function to detect malfunctions early and implement a redundant safety strategy. Power electronics module For the purposes of this patent application, a power electronics module is an electronic circuit designed to supply and control electric drives or actuators with the required currents and voltages. Such a power electronics module may include semiconductor switches, driver circuits, current and voltage measuring devices, and other control and safety components to provide and monitor the performance parameters required in the respective application. Advantageously, the power electronics module is integrated into or combined with a control unit so that the control and regulation of, for example, excitation coils and / or motor windings can be carried out efficiently and precisely. Steering sensors For the purposes of this patent application, a steering sensor system is a system consisting of one or more sensors and, optionally, associated signal processing, which detects the position, movement and / or other steering-relevant variables and provides measured values ​​in a suitable form. Steering sensors are preferably used to detect the current steering angle or the steering force applied by the driver, so that the control units of the steer-by-wire system can reliably initiate the desired vehicle steering movements. Preferably, rotary angle sensors are used, which essentially determine the rotation angle of the steering device, such as a steering wheel or joystick, and provide it as an electrical output signal for further evaluation by the control units. Advantageously, the steering sensor system includes evaluation electronics in close proximity to the sensors, which promotes precise acquisition of the measured values ​​and largely reduces interference from the vehicle environment. Rotation angle sensor For the purposes of this patent application, a rotary angle sensor is a component used to detect or determine a defined angle of rotation of a rotatable component and thereby provides an output signal representing the instantaneous angular position. The rotary angle sensor is preferably used to measure the position of steering elements in order to continuously transmit data about the current angle of rotation to the higher-level control unit. Advantageously, angle measurement is performed without contact, as the rotary angle sensor utilizes a magnetic, optical, or inductive measuring principle to detect changes in the relative position between a shaft and a stationary reference element. Preferably, the sensor design comprises a permanently magnetized rotor section fixed to the rotatable axis and a stationary sensor housing containing the evaluation electronics and measuring structure. This eliminates both sliding and frictional contacts, allowing the signal to be acquired without mechanical wear and ensuring a long service life. The electronics within the sensor housing process the measurement signal directly and provide it as analog or digital output signals. This output signal is then used, for example, by the control units of the steer-by-wire steering system for angle determination and control. Signal processing module For the purposes of this patent application, a signal processing module is an electronic component or assembly that serves to receive, process, and output input signals from one or more sensors. The signal processing module performs the function of converting and / or filtering the analog or digital signals originating from rotary angle sensors or other measuring systems and prepares them for further processing by the associated control units or actuators. Advantageously, the signal processing module consists of a microprocessor or microcontroller with appropriate software and hardware components, such as analog-to-digital converters, filter algorithms, and evaluation functions for analyzing sensor data. Preferably, the signal processing module is capable of both supplying power to the sensors and evaluating the resulting signals to generate precise and timely control commands. It can also perform processing functions such as error detection or plausibility checks of the received signals to ensure signal integrity. The electrical conductors for powering the control unit via the roadwheel actuator can be implemented in various cable configurations, specifically tailored to the respective requirements. For example, a multi-core cable bundle can be used, in which the current-carrying conductors for supplying the excitation coils are carefully shielded and additionally equipped with ferrite filters or other EMC-specific filter elements. This filtering can be achieved using special L / C filter stages or integrated interference suppression chokes, thus suppressing potential high-frequency interference signals at the source. One possible embodiment involves embedding the conductors in a common foil shield, which in turn is embedded in a flexible, chemically resistant outer layer to protect the cables against mechanical stress, moisture, and dirt. Similarly, individual current-carrying conductors can be twisted in pairs and each separately shielded to minimize interference and ensure signal quality during feedback or rapid current changes. The mechanical termination is preferably designed such that robust, sealable connector housings are fitted to both cable ends, ensuring a reliable connection even under vibration or large temperature fluctuations.In this way, on the one hand, a safe and interference-free energy transfer is ensured when energizing the excitation coils, and on the other hand, integration into existing vehicle architectures can be carried out without problems, since the system components adhere to defined EMC and safety standards. Preferably, the steer-by-wire steering system of the motor vehicle further comprises a control unit for acquiring and / or providing a steering command and a road wheel actuator for the mechanical implementation of the steering command at at least one wheel of the motor vehicle, wherein the control unit comprises a force feedback actuator having at least one energizable brake with a magnetic field generating device, which has at least one first energizable excitation coil, wherein the magnetic field of the first excitation coil, in the energized coil state, acts on a steering shaft of the control unit in such a way that the latter can be subjected to a braking torque, wherein the control unit has an associated first control unit and the road wheel actuator has an associated second control unit, wherein the at least first excitation coil can be energized by the first control unit of the control unit and / or by the second control unit associated with the road wheel actuator.This offers the advantage that both the control unit and the roadwheel actuator are able to selectively energize the excitation coil. This allows for flexible allocation of control and safety functions: If one control unit fails, the other can continue to generate the required braking torque. This increases the overall reliability of the system, which is particularly beneficial in safety-critical applications. According to an advantageous embodiment of the invention, the magnetic field generation device may include at least one second excitation coil, wherein the magnetic field of the second excitation coil, when energized, acts on the steering shaft of the control unit in such a way that the steering shaft can be subjected to a braking torque, and wherein the second excitation coil can be energized by the first control unit associated with the control unit and / or by the second control unit associated with the roadwheel actuator. Advantageously, the invention can thus also be further developed such that a second excitation coil can apply an additional or alternative braking torque to the steering shaft. This leads to a further increase in reliability, since if one coil malfunctions, the other coil can continue to generate braking force.Furthermore, flexibility in terms of control strategies is increased because two independently controllable coils can apply different torques. This allows for a more sensitive driving experience while simultaneously increasing the level of safety. According to a further preferred embodiment of the invention, it can also be provided that the first excitation coil and / or the second excitation coil can each be energized exclusively via the second control unit assigned to the roadwheel actuator. This allows for a clear separation of functions within the overall system and thus reduces configuration complexity. Technically, this results in improvements in electromagnetic compatibility, as the number of potential current paths is reduced and sources of interference can be addressed more effectively. Economically, this can lead to more cost-effective and simpler wiring. Furthermore, according to another advantageous embodiment of the invention, the force feedback actuator may have at least a second energized brake with a magnetic field generation device, which has at least a third energized excitation coil. The magnetic field of the third excitation coil, when energized, acts on a steering shaft of the control unit in such a way that the steering shaft can be subjected to a braking torque. The third excitation coil can be energized by the first control unit associated with the control unit and / or by the second control unit associated with the road wheel actuator. The inclusion of a second energized brake with a further excitation coil is therefore particularly advantageous. This allows for a higher maximum braking power or even finer gradation of the braking effect, resulting in refined haptic feedback.Furthermore, redundancy in the overall system increases, as several brake components can be controlled independently. This leads to increased reliability and opens up additional design possibilities with regard to steering dynamics. According to a further particularly preferred embodiment of the invention, the magnetic field generation device of the second brake may have at least a fourth excitation coil, wherein the magnetic field of the fourth excitation coil, when energized, acts on the steering shaft of the control unit in such a way that the latter can be subjected to a braking torque, and wherein the fourth excitation coil can be energized by the first control unit associated with the control unit and / or by the second control unit associated with the roadwheel actuator. This allows several different braking torques to be generated in parallel or alternatively without the need for additional external modules. This promotes a modular system architecture in which the individual braking functions can be activated depending on the driving situation.Such flexibility can not only increase driving comfort, but also safety, as the appropriate braking power is available at all times. According to a further particularly preferred embodiment of the invention, it can be provided that the magnetic field generating device of the second brake has at least a fourth excitation coil, wherein the magnetic field of the fourth excitation coil in the energized coil state acts on the steering shaft of the control unit in such a way that it can be subjected to a braking torque, wherein the fourth excitation coil can be energized by the first control unit associated with the control unit and / or by the second control unit associated with the roadwheel actuator. Furthermore, the invention can also be further developed such that the third excitation coil and / or the fourth excitation coil can each be energized exclusively via the second control unit assigned to the roadwheel actuator. This simplifies the hardware architecture and facilitates the diagnosis of malfunctions, as it is clearly possible to assign which control unit is responsible for which brake coils. In this way, the system becomes easier to maintain, while at the same time manufacturing costs can be reduced due to lower complexity. In a preferred embodiment of the invention, the first control unit of the operating unit can also be configured with a first power electronics module for energizing one of the excitation coils and a second power electronics module for energizing the same and / or a different excitation coil. Advantageously, the operating unit can thus be equipped with several power electronics modules that energize either the same or different excitation coils. This creates a redundant concept that ensures sufficient brake control even if one module fails. Furthermore, the distribution across different modules allows for precise and finely adjustable control of the braking torque, as different current intensities or switching frequencies can be provided. It can also be advantageous to further develop the invention such that the second control unit of the roadwheel actuator is configured with a third power electronics module for energizing one of the excitation coils and a fourth power electronics module for energizing the same and / or a different excitation coil. Likewise, it is particularly advantageous if the roadwheel actuator also has several power electronics modules that cover its braking functions. This contributes significantly to the redundancy of the overall steering system. Furthermore, complex steering strategies can be implemented in which, for example, individual braking modules are primarily used for safety functions and others for comfort functions. This results in a flexible and efficient steering concept. According to a further preferred embodiment of the invention, the first energizable brake and / or the second energizable brake can be designed as a magnetorheological brake. This allows the braking torque acting on the steering shaft to be changed very quickly and continuously. A magnetorheological medium reacts immediately to changes in the magnetic field, resulting in highly dynamic steering feel. Furthermore, such brakes generally exhibit low wear, which reduces maintenance costs. Finally, the invention can also advantageously be implemented such that the first energizable brake and / or the second energizable brake are directly connected to the second control unit of the roadwheel actuator. This direct connection avoids unnecessary interfaces, which has a positive impact on reliability and cost structure. At the same time, data communication is simplified, allowing for efficient integration into the existing vehicle architecture. In a further advantageous embodiment of the invention, the steer-by-wire steering system of a motor vehicle can be further developed to include a control unit for acquiring and / or providing a steering command and a road wheel actuator for the mechanical implementation of the steering command at at least one wheel of the motor vehicle. The control unit comprises a force-feedback actuator, which is connected via a first steering sensor with a first angle sensor. The control unit has an associated first control unit, and the road wheel actuator has an associated second control unit. The first angle sensor of the control unit can be energized via the second control unit associated with the road wheel actuator. This embodiment offers the advantage that the energy supply of an essential sensor of the control unit can be provided from a different control path—specifically, from the control unit associated with the road wheel actuator.This creates increased reliability and redundancy because a stable power supply to the steering angle sensor is guaranteed even in the event of a failure or malfunction in the control unit. This leads to overall higher operational reliability of the entire steer-by-wire system and contributes in particular to reliable detection of the steering wheel position. From an economic perspective, the targeted distribution of power supply to separate control areas allows for a more efficient system architecture and reduces wiring effort, ultimately resulting in lower manufacturing and maintenance costs. According to an advantageous embodiment of the invention, the roadwheel actuator can be provided with a second steering sensor system comprising a second rotary angle sensor, the output signal of which can be transmitted to the first control unit of the operating unit. Advantageously, the invention can thus be further developed such that the additional detection of the wheel position in the roadwheel actuator provides a complete picture of the steering position in both control paths. The output signal of the second rotary angle sensor is transmitted to the operating unit, enabling direct evaluation or plausibility checks of the actual set wheel position. In this way, not only can improved steering control be achieved, but diagnostic capabilities can also be enhanced by allowing deviations between the desired and the actual set steering position to be detected at an early stage.From a technical point of view, this increases the control quality, while economic advantages result from simplified system integration because the control unit receives precise information about the wheel condition and does not require additional complex sensors. According to a further preferred embodiment of the invention, the first rotary angle sensor of the control unit can also be powered exclusively via the second control unit, which is associated with the roadwheel actuator. This configuration, in which the first rotary angle sensor of the control unit is supplied exclusively from the control unit associated with the roadwheel actuator, ensures a particularly clear and robust separation between the signal path of the control unit and the signal path of the actuator side. The exclusive power supply via the second control unit enables a stringent safety architecture in which potential faults in the control unit cannot affect the sensor power supply. This contributes to greater robustness against partial or complete failures in individual system areas.In addition, this ensures optimal monitoring and control of the sensor power supply, which is essential, especially with regard to functional safety and compliance with legal requirements for steer-by-wire systems. Furthermore, according to another advantageous embodiment of the invention, the control unit may include a third rotary angle sensor, which can be powered via the first control unit associated with the control unit and / or via the second control unit associated with the roadwheel actuator. The possibility of powering a third rotary angle sensor of the control unit via the first and / or second control unit enables a flexible and highly available system design. Technically, this makes a multi-path or multi-power supply concept for critical sensors feasible, ensuring the continuity of measurement operation even if one of the control units fails or malfunctions. This increases the overall reliability and safety of the steering function.Furthermore, economic advantages arise because complete component redundancy is not always necessary: ​​Instead of supplying two independent sensors exclusively from separate control units, a single sensor can be flexibly powered by either of the two control units. This simplifies manufacturing and maintenance and reduces the system's complexity. It would also be advantageous if the output signal of the first and / or third rotary angle sensor could be transmitted to the second control unit of the roadwheel actuator. If the output signal of the first and / or third rotary angle sensor could be transmitted to the second control unit of the roadwheel actuator, the wheel-side control unit could directly access the exact position information from the operating unit. This enables improved synchronization between the desired and executed steering position, as the second control unit could independently perform plausibility checks and react quickly in case of deviations. Such decentralized evaluation can also reduce the load on the operating unit and contribute to faster, more localized control in the roadwheel actuator. Economically, this allows for a leaner and more modular system architecture, as each control unit can take on specific tasks and no elaborate detours are necessary in signal processing. In a further preferred embodiment of the invention, the first control unit of the operating unit may also be configured with a first signal processing module and a second signal processing module for powering and / or evaluating the same and / or a different rotary angle sensor of the operating unit. The use of a first and a second signal processing module in the control unit of the operating unit, which can selectively power and / or evaluate the same or different rotary angle sensors, significantly increases the scalability and flexibility of the electronics. Technically, the division into multiple signal processing lines means that if one module fails, the function can be ensured or supported by the other module. This not only increases availability but also creates the possibility of implementing different signal processing concepts in parallel (e.g.,...).redundant evaluation or different evaluation methods). From an economic point of view, the system can be used in different vehicle classes without having to develop a completely new electronics platform in each case. According to a further preferred embodiment of the invention, the second control unit of the roadwheel actuator can be configured with a third signal processing module for powering and / or evaluating the same and / or a different rotary angle sensor of the roadwheel actuator. The integration of a third signal processing module in the control unit of the roadwheel actuator, which is also designed for powering and / or evaluating rotary angle sensors, enables a further increase in functional reliability and redundancy. Technically, this allows not only for the provision of an autonomous sensor signal processing system, but also for the distribution of the computing load. This decentralization leads to greater stability in the event of a fault, because failures of one signal processing module do not directly affect the other part of the system.Furthermore, the use of a separate module allows for synergy effects in hardware and software design, as functionally critical tasks can be specifically outsourced and secured. It can also be advantageous to further develop the invention such that the rotary angle sensors of the control unit are essentially identical. The largely identical design of the rotary angle sensors in the control unit offers significant advantages in terms of standardization and ease of maintenance. Technically, calibration is simpler because, with identical sensor types, both units have similar or even identical characteristic curves, and the same evaluation algorithms can therefore be used. Furthermore, this reduces storage and procurement costs on an economic level, as only a single sensor variant needs to be procured in larger quantities and can be installed in both the control unit and the roadwheel actuator, or in a redundant configuration. This leads to lower spare parts costs and simplifies servicing. Furthermore, it is also preferable that at least one of the rotary angle sensors of the control unit and the rotary angle sensor of the roadwheel actuator are essentially identical. The possibility of at least one of the rotary angle sensors of the control unit and the rotary angle sensor of the roadwheel actuator being essentially identical offers numerous advantages in production and logistics. For example, a standardized supply chain can be established, as only one type of sensor needs to be stocked. This also enables simplified quality control, because all sensors can be tested according to the same parameters. Technically, the steer-by-wire steering system becomes more homogeneous, since similar measurement characteristics exist in both areas, which makes the overall system easier to tune. Due to the reduced complexity, manufacturers and end customers alike benefit from increased efficiency, reduced costs, and enhanced ease of use. Furthermore, a steer-by-wire steering system for a motor vehicle is also preferred, comprising a control unit for detecting and / or providing a steering command and a road wheel actuator for the mechanical implementation of the steering command at at least one wheel of the motor vehicle, wherein the control unit comprises a force feedback actuator which has a first steering sensor with a first angle sensor, wherein the control unit has an associated first control unit and the road wheel actuator has an associated second control unit, wherein the first angle sensor of the control unit can be energized via the second control unit associated with the road wheel actuator. This embodiment offers the advantage that the power supply for a key sensor of the control unit can be provided from a different control path – specifically, from the control unit associated with the roadwheel actuator. This creates increased reliability and redundancy because a stable power supply to the steering angle sensor is still guaranteed in the event of a failure or malfunction in the control unit. This leads to an overall increase in the operational reliability of the entire steer-by-wire system and, in particular, contributes to reliable detection of the steering wheel position. From an economic perspective, the targeted distribution of the power supply across separate control areas allows for a more efficient system architecture and a reduction in wiring complexity, ultimately resulting in lower manufacturing and maintenance costs. According to a further preferred embodiment of the invention, a steer-by-wire steering system of a motor vehicle can be provided, comprising a control unit for sensing and / or providing a steering command and a road wheel actuator for the mechanical implementation of the steering command at at least one wheel of the motor vehicle, wherein the control unit comprises a force feedback actuator, having at least one first electric motor with at least one currentable first winding, wherein the first motor, when energized, acts on a steering shaft of the control unit in such a way that the latter can be subjected to a braking torque, wherein the control unit has an associated first control unit and the road wheel actuator has an associated second control unit, wherein the at least first winding of the first motor can be energized by the first control unit of the control unit and / or by the second control unit associated with the road wheel actuator. This steer-by-wire steering system offers the advantage that at least one winding of the electric motor can be powered by a control unit at the operating unit as well as by a control unit at the road wheel actuator. Due to the physical separation of the operating unit from the road wheel actuator, potential sources of error are confined to one of the two areas, so that a local failure of one control unit does not affect the operation of the other. This separation further isolates external influences, such as mechanical damage to the vehicle at one point, resulting in increased reliability, robustness, and flexibility of the steer-by-wire system. According to an advantageous embodiment of the invention, the first electric motor can have at least one second energizable winding, wherein the second winding can be energized by the first control unit associated with the operating unit and / or by the second control unit associated with the roadwheel actuator. Advantageously, the motor can therefore also have an additional winding, which in turn is selectively energized either by the control unit at the operating unit or by the control unit at the roadwheel actuator. In combination with the spatial distance between the two control units, this results in particularly robust redundancy, since each winding is protected not only electronically, but also mechanically and / or spatially separately by the placement of the control units.This ensures that sufficient steering or braking torque is maintained even if a control unit or wiring harness in the area of ​​the control unit or in the area of ​​the roadwheel actuator fails or is damaged. According to a further preferred embodiment of the invention, it can also be provided that the first winding and / or the second winding can each be energized exclusively via the second control unit assigned to the roadwheel actuator. The exclusive control of individual windings via only one of the two control units has the additional advantage that a clear functional separation between the control unit located near the driver's seat and the control unit located decentrally on the roadwheel actuator can be achieved. The spatial distance between these units helps to ensure that potential defects within one control unit or wiring harness section do not impair the functionality of the other control unit. This facilitates the development of a simpler and, at the same time, safety-optimized control architecture. Furthermore, according to another advantageous embodiment of the invention, the force feedback actuator may have at least one second electric motor with at least one third energizable winding, wherein the second electric motor, when energized, acts on a steering shaft of the control unit such that the latter can be subjected to a braking torque, and wherein the third winding can be energized by the first control unit associated with the control unit and / or by the second control unit associated with the roadwheel actuator. If a second electric motor is provided for generating the force feedback, the advantages of the decentralized, spatially separated control units can be further enhanced. Finely tuned control of both rotational and braking torques via two motors becomes particularly stable and robust due to the separate placement of the control hardware.A local failure or the influence of external factors, such as an accident or extreme temperature effects in one area of ​​the vehicle, does not necessarily affect the other, spatially distant control area. According to a further particularly preferred embodiment of the invention, the second electric motor may have at least a fourth winding, wherein the fourth winding can be energized by the first control unit associated with the operating unit and / or by the second control unit associated with the roadwheel actuator. By adding at least one additional winding to the second electric motor, the decentralized control system can be further optimized. Since each additional winding can be energized either by the control unit at the operating unit or by the control unit at the roadwheel actuator, even greater robustness against disturbances in a specific area of ​​the vehicle is achieved. This physical separation prevents, for example, mechanical influences on the wheels from simultaneously affecting the operating unit.Conversely, a problem near the control unit cannot cripple the entire system because the control unit remains usable in the area of ​​the roadwheel actuator. In a preferred embodiment of the invention, it can also be provided that the third winding and / or the fourth winding can each be energized exclusively via the second control unit assigned to the roadwheel actuator. Energizing individual windings exclusively via a specific, spatially separated control unit facilitates a clear division of tasks and simultaneously increases operational reliability. In this way, it is ensured that each winding and each motor lies within a clearly defined area of ​​responsibility of a control unit, which in turn is located in a different position within the vehicle. If, for example, a fault occurs in the operating unit, the possibility of supplying power via the more distant control unit at the roadwheel actuator remains, and vice versa. The invention can also be further developed such that the first control unit of the operating unit is configured with a first power electronics module for energizing one of the windings and a second power electronics module for energizing the same and / or a different winding. The use of several separately designed power electronics modules within a control unit on the operating unit enables double redundancy when spatially separated from the roadwheel actuator. If one of these modules fails due to localized damage to the operating unit, the other module can continue operation in that area of ​​the vehicle, while the second, more distant control unit on the roadwheel actuator also provides a completely independent alternative. This results in a high degree of availability, as the power supply is not only electronically but also mechanically protected thanks to the decoupling by different vehicle zones. Furthermore, it may be advantageous for the second control unit of the roadwheel actuator to be configured with a third power electronics module for energizing one of the windings and a fourth power electronics module for energizing the same and / or a different winding. Equipping the control unit, which is located separately on the roadwheel actuator, with multiple power electronics modules further enhances the advantages described. Since each module is installed locally at a sufficient distance from the operating unit, the other module or control unit remains functional even if one area of ​​the vehicle experiences a malfunction or damage. This allows the second area to continue supplying power to the windings in critical situations, even in the event of a partial or total failure of a power stage in one area, thus increasing the overall operational reliability and dependability of the steer-by-wire system. It goes without saying that all of the aforementioned features can be combined in any meaningful way to further optimize the steer-by-wire steering system and / or adapt it to given requirements. For example, it would be possible to combine features from the redundancy approach for brake power supply with features from the redundancy approach for steering sensor power supply and / or with features from electric motor power supply in any meaningful way. The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention. It shows: Fig. 1 a motor vehicle with a steer-by-wire steering system in a schematic representation, Fig. 2 a control unit in a perspective view, Fig. 3 a control unit in a perspective axial sectional view, Fig. 4 an axial sectional view of a magnetorheological brake of the control unit, Fig. 5 a motor vehicle with a steer-by-wire steering system in a schematic representation with a connection of the excitation coils to the first control unit of the control unit and to the second control unit, associated with the roadwheel actuator, in a first embodiment, Fig. 6 a motor vehicle with a steer-by-wire steering system in a schematic representation with a connection of the excitation coils to the first control unit of the control unit and to the second control unit, associated with the roadwheel actuator, in a second embodiment, Fig.Fig. 7 A motor vehicle with a steer-by-wire steering system in a schematic representation showing a connection of the excitation coils with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a third embodiment, Fig. 8 A motor vehicle with a steer-by-wire steering system in a schematic representation showing a connection of the excitation coils with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a fourth embodiment, Fig. 9 A motor vehicle with a steer-by-wire steering system in a schematic representation showing a connection of the excitation coils with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a fifth embodiment, Fig.Fig. 10 A motor vehicle with a steer-by-wire steering system in a schematic representation showing a connection of the steering sensors with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a first embodiment, Fig. 11 A motor vehicle with a steer-by-wire steering system in a schematic representation showing a connection of the steering sensors with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a second embodiment, Fig. 12 A motor vehicle with a steer-by-wire steering system in a schematic representation showing a connection of the electric motor with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a first embodiment, Fig.Fig. 13 a motor vehicle with a steer-by-wire steering system in a schematic representation with a connection of the electric motor to the first control unit of the operating unit and to the second control unit assigned to the roadwheel actuator in a second embodiment, Fig. 14 a motor vehicle with a steer-by-wire steering system in a schematic representation with a connection of the electric motor to the first control unit of the operating unit and to the second control unit assigned to the roadwheel actuator in a third embodiment, Fig. 15 a motor vehicle with a steer-by-wire steering system in a schematic representation with a connection of the electric motor to the first control unit of the operating unit and to the second control unit assigned to the roadwheel actuator in a fourth embodiment, Fig.Fig. 16 a motor vehicle with a steer-by-wire steering system in a schematic representation with a connection of the electric motor with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a fifth embodiment, Fig. 17 a motor vehicle with a steer-by-wire steering system in a schematic representation with a connection of the electric motor, the brake and the steering sensors with the first control unit of the operating unit and with the second control unit assigned to the roadwheel actuator in a first embodiment. Fig. 1 shows a steer-by-wire steering system 1 of a motor vehicle 2 with a steering device 45. The steering system 1 comprises a control unit 4 arranged in the passenger compartment 141, which receives a steering command from a user or a control unit, which may, for example, be part of an autonomous or semi-autonomous driving system of the motor vehicle 2, and transmits it electrically or optically to a road wheel actuator 6 of a front axle steering system 3, which then converts the corresponding steering command into a steering movement of the vehicle wheels 7a, 7b. It is also conceivable that a rear axle steering system or individual wheel steering systems could implement the steering command. The control unit 4, located in the passenger compartment 141, detects the driver's steering input via the steering device 45 or receives corresponding signals from a vehicle-integrated control unit. Sensors that detect rotation angle, torque, or other parameters transmit the signal to a control electronics unit, which then sends the steering command to the roadwheel actuator 6. This roadwheel actuator 6 converts the electrical or optical control signal into a mechanical steering movement, which preferably acts on the vehicle wheels 7a, 7b of the front axle via a linkage or direct drives, thus generating the desired steering angle. Advantageously, the roadwheel actuator 6 can also be equipped with additional sensors, allowing feedback on road conditions, forces, or the respective wheel steering angle to be fed back to the control electronics unit.In this way, adaptive control strategies can be implemented, for example, stabilizing driving behavior in critical driving situations or in autonomous driving mode where steering movements are initiated exclusively by the control unit. Eliminating a direct mechanical connection between the steering element 45 and the steering mechanisms saves costs and installation space, as well as reducing potential vibrations or disturbances in the interior. Fig. 2 shows the control unit 4 in a perspective view. The control unit 4 comprises a telescopic extension 46, which has a tubular extension carrier 138 and a telescopic slide 137 that is translationally movable within it. Fig. 2 shows the telescopic extension 46 with a telescopic slide 137 extended. The translational movement of the telescopic slide 137 within the tubular extension carrier 138 allows for precise adjustment of the axial position of the steering element 45 relative to the driver, thus achieving an ergonomically optimal distance. In the embodiment shown in Fig. 2, the telescopic slide 137 is mounted with low friction in an internal guide of the extension carrier 138. The integration of the extension carrier 138 into the steering column adjustment 42 also enables adjustment of the tilt of the entire control unit 4, allowing the driver to assume an individually adapted seating and operating position. The steering shaft 43 runs essentially coaxially with the telescopic slide 137 and the extension carrier 138 and protrudes from the end of the telescopic slide 137 closest to the steering element.The steering device 45 can be attached to this prominent shaft section, so that the rotary movements of the steering device 45 are transmitted to the steer-by-wire system or detected there via the steering shaft 43. Figure 3 shows the internal components of the telescopic slide 137. It can be seen that a force-feedback actuator 41 with an electric motor 109 and a brake 107, designed as a magnetorheological brake 108, are arranged inside the telescopic slide 137. Furthermore, a rotation angle limiter 44 is arranged in the telescopic slide 137. Figure 3 clearly shows that the telescopic slide 137 is designed to accommodate all functionally important components of the steer-by-wire system in a compact form and simultaneously provide axial adjustment capability. The steering shaft 43 passes through both the steering angle limiter 44 and the force feedback actuator 41 with the electric motor 109 and the brake 107, and is connected to each of these components. A torque can be transmitted to the steering shaft 43 via the motor 109 and the brake 107. The torque generated or applied by the motor 109 is transmitted to the steering shaft 43, so that the driver experiences an active steering feel and receives targeted feedback via the steering wheel. The magnetorheological brake 108 is integrated into this force flow to generate an adjustable damping or braking torque by selectively changing the viscosity of its magnetorheological medium. This allows the braking effect to be continuously controlled, enabling precise regulation of the steering feel and the restoring forces. The rotation angle limiter 44 provides a defined mechanical end stop in each direction of rotation of the steering shaft 43. The rotation angle limiter 44 detects the position of the steering shaft 43 and mechanically ensures that a defined end-stop torque occurs in both directions of rotation, thus preventing over-rotation or damage to the system. Since the steering shaft 43 passes through the rotation angle limiter 44, the motor 109, and the brake 107, it is ensured that all components are coaxially aligned and that the desired force and torque management can be carried out with high precision and a short response time. Based on Fig. 2-3, it is easy to understand that the operating unit 4 has a telescopic extension 46, with an extension carrier 138 and a telescopic slide 137 which is translationally movable relative to the extension carrier 138. The steering shaft 43 is rotatably mounted within the telescopic slide 137. A rotation angle limiter 44 and an energized force feedback actuator 41 with an energized electric motor 102 and an energized brake 107 are arranged within the telescopic slide 137. The brake 107, the force feedback actuator 41, and the rotation angle limiter 44 are arranged within the telescopic slide 137 such that, starting from the distal end of the telescopic slide 137 closest to the steering center, the rotation angle limiter 44, then the brake 107, and then the electric motor 102 follow the path towards the end of the telescopic slide 137 furthest from the steering center. Figure 4 shows an embodiment of an energized brake 107 in the form of a magnetorheological brake 108, which is integrated as a force-feedback actuator 41 into a control unit 4 for a steer-by-wire steering system 1. The brake 108 has a brake stator 114 and a brake rotor 109 that is rotatable relative to it and can be coupled to the steering wheel via a steering shaft 43. A braking torque acting on the brake rotor 109 can be generated by means of a magnetic field generation device 117 by energizing two excitation coils, a first excitation coil 120a and a second excitation coil 120b. The first excitation coil 120a is arranged radially inside the second excitation coil 120b, so that the magnetic field can be transferred to the magnetorheological medium in the gap between brake stator 114 and brake rotor 109 either through one or both coils.Through targeted activation, the viscosity of the magnetorheological medium changes, leading to a variable torque transmission and thus generating the braking effect relevant for force feedback. To precisely separate the magnetic fields and prevent unwanted interference, a separating element 901 is arranged radially between the first excitation coil 120a and the second excitation coil 120b. This separating element 901 can be designed as a foil or as a cylindrical sheet metal ring and is preferably electrically insulated so that no short circuits or interference occur. In the illustrated embodiment, the excitation coils 120a and 120b have an axial extent that is 90 to 110% the same for both coils, and a number of turns in a ratio of approximately 0.8 to 1.2. Furthermore, both coils preferably have a comparable conductor diameter between 0.3 and 0.5 mm, resulting in largely identical current density and thermal behavior for both excitation coils 120a and 120b. It is also clearly evident that the two excitation coils 120a and 120b have a rectangular cross-section, with the radially extending portion being smaller than the axially extending portion. Both excitation coils 120a and 120b can be energized by connecting conductors 905a and 905b. Separate control of the excitation coils 120a and 120b is also possible. The conductors 905a and 905b of the excitation coils 120a and 120b are routed axially out of the brake 107 through a cable duct 907. To maintain both excitation coils 120a, 120b at a stable and reproducible distance from each other and to guide the magnetic flux in a controlled manner, a ring-shaped coil support 902 is provided, which is made of a non-magnetizable and preferably metallic material with a material thickness of approximately 0.5 to 1.0 mm. This coil support 902 has a circumferentially U-shaped cross-sectional profile, at least partially, with a first free leg 903a and a second free leg 903b. The extent of the first leg 903a is less than the extent of the second leg 903b, so that the conductors 905a, 905b of the radially inner excitation coil 120a, which are provided for electrical connection, can be led out radially above the shorter first leg 903a. In this way, efficient cable routing is enabled, while the excitation coils 120a, 120b are securely held by the coil carrier 902. The brake stator 114 shown can be positioned either radially outside (as shown in Fig. 4) or inside the brake rotor 109 to accommodate different installation situations in the vehicle 2. An axially offset arrangement is also conceivable, in which the excitation coils 120a, 120b are still located on the brake stator 114. Finally, the brake rotor 109 is provided on its circumferential surface facing the brake stator 114 with a U-shaped groove 904 in cross-section, in which the excitation coils 120a, 120b are placed, at least partially. This groove 904 and the described arrangement result in an optimal magnetic circuit and high braking precision through targeted guidance and limitation of the magnetorheological effective zone. Figure 5 shows a possible embodiment of a steer-by-wire steering system 1 according to the invention for a motor vehicle 2, comprising a control unit 4 for acquiring and / or providing a steering command and a road wheel actuator 6 for the mechanical implementation of the steering command at at least one wheel 7 of the motor vehicle 2. The distribution of the steering torque to the wheel 7 is effected by means of powerful electric or electro-hydraulic drives that convert the incoming control signal into a defined steering force. Sensory feedback, such as rotation angle and torque at the wheel suspension, can be continuously incorporated into the control logic to ensure optimal control of the steering behavior. The control unit 4 comprises a force-feedback actuator 41, having at least one energized brake 107a with a magnetic field generating device 117a which has at least one first energized excitation coil 120a, wherein the magnetic field of the first excitation coil 120a, when energized, acts on a steering shaft 43 of the control unit 4 such that it can be subjected to a braking torque. The brake 107a can, for example, be constructed like the brake 107 from Fig. 4, but with only one excitation coil 120a. By applying a current to the first excitation coil 120a, a magnetic field is generated in the magnetic field generating device, which influences either a magnetorheological medium or magnetically effective friction elements. As a result, a controlled braking torque is generated on the steering shaft 43, whereby the steering feel for the driver can be simulated or adjusted.This design enables rapid control of the rotational movement of the steering shaft 43, as the electrical current flow can be adjusted almost instantaneously. This allows, for example, load change reactions, varying road conditions, or driving situations such as parking or emergency braking to be transmitted to the steering feedback. The system can also dampen mechanical vibrations, thereby providing more harmonious feedback to the driver. The control unit 4 has an associated first control unit 5a, and the roadwheel actuator 6 has an associated second control unit 5b. At least the first excitation coil 120a can be energized by the first control unit 5a of the control unit 4 and by the second control unit 5b, which is associated with the roadwheel actuator 6, as indicated by the dashed lines in Fig. 5. This results in redundancy, which significantly increases operational reliability. If one control unit 5a or 5b fails, the remaining control unit can take over the energizing of the excitation coil 120a, thereby ensuring partial or even complete continued operation of the steering function. This division of the power supply paths also leads to a more flexible system architecture: Depending on the operating state, the control system can, for example, access the power supply optimally adapted to the respective driving situation.Furthermore, efficient load distribution is achieved by distributing the electrical requirements across two control units. The magnetic field generating device 117 of the brake 107a also includes a second excitation coil 120b, wherein the magnetic field of the second excitation coil 120b, when energized, acts on the steering shaft 43 of the control unit 4 such that it can be subjected to a braking torque. The second excitation coil 120b can be energized by the first control unit 5a, associated with the control unit 4, and / or by the second control unit 5b, associated with the roadwheel actuator 6. The brake 107a can, for example, be constructed like the brake 107 shown in Fig. 4. The addition of a second excitation coil 120b enables even finer gradation and control of the braking torque acting on the steering shaft 43. Advantageously, the control unit can now generate two different magnetic fields, which can be switched either simultaneously or sequentially to achieve different damping levels or a finer torque curve.This allows even complex scenarios to be reliably simulated, for example, those requiring rapid switching between high and low braking torques. At the same time, reliability is increased, as the second excitation coil 120b can continue to supply the system with sufficient braking torque if the first excitation coil 120a malfunctions. This design thus creates a highly dynamic and extremely flexible steering feel simulation that can be precisely adapted to various vehicle or environmental conditions. Figure 6 shows an embodiment in which the first excitation coil 120a and the second excitation coil 120b of the first brake 107a can be energized exclusively via the second control unit 5b, which is associated with the roadwheel actuator 6. This design makes it possible to implement the entire braking function for the operating unit 4 via a central power and control path provided by the control unit 5b. Advantageously, this results in a uniform control strategy, since a single control algorithm coordinates the intensity of the two excitation coils. This means that the control of the braking torque on the steering shaft 43 is more consistent, as all relevant measurement and control parameters are processed centrally in the control unit 5b. Furthermore, critical safety and diagnostic functions can be bundled in a single hardware and software environment, which reduces both integration effort and potential error rates.Furthermore, by relying solely on the control unit 5b, it can be ensured that in the event of a potential malfunction of the first control unit 5a, full braking effectiveness is maintained, provided that the second control unit 5b remains operational. Figure 7 shows an embodiment in which the first excitation coil 120a can be energized exclusively via the first control unit 5a, and the second excitation coil 120b of the first brake 107a can be energized exclusively via the second control unit 5b, which is assigned to the roadwheel actuator 6. In this variant, the system benefits from a targeted division of the control and supply paths. By assigning the first excitation coil 120a exclusively to the control unit 5a, it can be operated and controlled independently of the roadwheel actuator 6. This offers, among other advantages, that the operating unit 4 can independently fine-tune the steering feel in certain operating modes—for example, at low speeds or during parking maneuvers—without being directly influenced by the control algorithms of the second control unit.Simultaneously, the second excitation coil 120b and the control unit 5b provide a continuously available means of applying braking torque to the steering shaft 43. This creates a flexible combination of local, finely tuned control and higher-level, safety-relevant control, ensuring a particularly robust steering feel simulation adapted to the operating conditions. Furthermore, distributing the power requirements across two separate units can reduce the thermal and electrical loads in the overall system by separating the current paths and relieving the control units of each other's load. This not only increases the reliability of the steering functions but also the service life and ease of maintenance of the components used. As shown in Fig. 4, the force feedback actuator 41 also has a second energizable brake 107b with a magnetic field generating device 117b, which has a third energizable excitation coil 120c, wherein the magnetic field of the third excitation coil 120c in the energized coil state acts on a steering shaft 43 of the control unit 4 in such a way that it can be subjected to a braking torque, wherein the third excitation coil 120c can be energized by the first control unit 5a associated with the control unit 4 and / or by the second control unit 5b associated with the roadwheel actuator 6.The magnetic field generating device 117 of the second brake 107b further comprises a fourth excitation coil 120d, wherein the magnetic field of the fourth excitation coil 120d, when energized, acts on the steering shaft 43 of the control unit 4 such that it can be subjected to a braking torque, wherein the fourth excitation coil 120d can be energized by the first control unit 5a, associated with the control unit 4, and / or by the second control unit 5b, associated with the roadwheel actuator 6. The second brake 107b can, for example, be constructed like the brake 107 shown in Fig. 4. The additional arrangement of this second brake 107b significantly increases the overall braking power and thus the braking torque that can be applied to the steering shaft 43. In particular, the excitation coils 120c and 120d make it possible to generate two independent magnetic fields, which can be combined or switched individually. This allows for highly variable force feedback adjustment. For example, simultaneously energizing several coils generates a higher braking torque for a particularly intense steering feel, while separate or staged activation enables precise adjustment of the steering resistance. This design also increases reliability, as the other excitation coil can provide the necessary braking torque if one fails. Furthermore, the distribution of power between the first control unit 5a and the second control unit 5b can be flexibly configured. Thus, during regular operation, the computing and power resources of both control units 5a and 5b can be used for precise control of the braking torque, while in emergency or failure mode, one control unit 5a or 5b alone takes over the power supply to the excitation coils 120. The mechanical integration of two brakes 107a and 107b in a compact assembly also offers advantages in terms of installation space, component weight, and heat dissipation. Figure 8 shows an embodiment in which the third excitation coil 120c and the fourth excitation coil 120d can be energized exclusively via the second control unit 5b, which is associated with the roadwheel actuator 6. In this configuration, the first energizable brake 107a (Figure 5) or the second energizable brake 107b (Figure 7) is directly connected to the second control unit 5b of the roadwheel actuator 6. This direct connection of the brakes to the second control unit 5b results in a particularly short signal chain. The signal paths between the control unit 5b and the excitation coils 120c and 120d are thus shortened, enabling fast and precise control of the braking torques acting on the steering shaft 43. This rapid response is particularly advantageous in safety-critical situations where high braking torques need to be applied quickly, for example to dampen jerky steering movements or in the event of imminent vehicle instability. At the same time, the direct connection can lead to a reduction in potential fault interfaces, as there are fewer lines and coupling points. Furthermore, the exclusive power supply via the second control unit 5b enables clear responsibility for diagnostics, so that faults in the brake control system can be precisely attributed to this control unit. Figure 9 shows an embodiment in which the third excitation coil 120c can be energized exclusively via the first control unit 5a, and the fourth excitation coil 120d of the second brake 107b can be energized exclusively via the second control unit 5b, which is associated with the roadwheel actuator 6. Furthermore, the first excitation coil 120a can be energized exclusively via the first control unit 5a, and the second excitation coil 120b of the first brake 107a can be energized exclusively via the second control unit 5b, which is associated with the roadwheel actuator 6. This creates a clear separation of responsibilities between the first control unit 5a and the second control unit 5b, thereby increasing redundancy in the overall system. Each control unit 5 monitors and controls specific excitation coils 120 and can continue to operate independently in the event of a failure in the other sub-area. Furthermore, this division of the excitation coils 120 allows for targeted adjustment of different braking characteristics.For example, the excitation coil 120c or 120a controlled by the first control unit 5a can be specialized to maintain a basic steering feel, while the excitation coils 120d or 120b powered by the second control unit 5b can generate high braking torques to simulate dynamic reactions or safety functions. This allows, for instance, a combination of very precise, sensitive feedback for tight maneuvering and the rapid application of high braking forces for emergency situations. This distribution of functions contributes to efficient load management within the system by supplying power to the excitation coils 120 via separate channels, thus preventing overloading of individual control units 5. At the same time, different control algorithms can be applied, as each control unit can be optimally configured for its respective excitation coils 120. As can also be seen in Figures 4-8, the first control unit 5a of the operating unit 4 is configured with a first power electronics module 162a for energizing one of the excitation coils 120 and a second power electronics module 162b for energizing the same and / or a different excitation coil 120. Similarly, the second control unit 5b of the roadwheel actuator 6 has a third power electronics module 162c for energizing one of the excitation coils 120 and a fourth power electronics module 162d for energizing the same and / or a different excitation coil 120. The use of multiple power electronics modules 162 in both control units 5 enables both a high degree of redundancy and finely graduated control of the current flow. Each power electronics module 162 can be controlled independently to cover specific operating conditions or fault scenarios.This makes it possible, for example, to operate only one module actively during normal operation and to switch on the second module as needed to provide a higher performance level or a faster response time. Additionally, the controller can implement different voltage and current profiles by distributing the modules across different excitation coils 120 or by supplying identical excitation coils 120 with different parameters. This modular design greatly simplifies adaptation to different driving situations, such as sporty driving, comfortable cruising, or highly dynamic evasive maneuvers in emergency situations. A further advantage is that if one power electronics module 162 fails, the overall steering function is maintained, as the other module can at least partially take over the power supply to the excitation coils 120. The design of the individual modules also allows for the decoupling of individual current paths, which increases electromagnetic compatibility and expands the diagnostic scope with regard to fault messages. In the illustrated embodiments, the first energizable brake 107a and the second energizable brake 107b are designed as magnetorheological brakes 108. The accompanying schematic diagram in Fig. 10 also shows a steer-by-wire steering system 1 of a motor vehicle 2, in which a control unit 4 is provided for acquiring and issuing a steering command. The control unit 4 comprises a force-feedback actuator 41 and has a first steering sensor 131a with a first rotation angle sensor 132a. This first rotation angle sensor 132a serves to determine the rotational position made by the driver with the steering wheel and can be powered by the second control unit 5b of the roadwheel actuator 6. This creates a redundant or alternative power supply, whereby the sensor of the control unit 4 can, if necessary, be operated not only by its associated first control unit 5a, but advantageously also by the second control unit 5b. In a preferred embodiment, shown in Fig. 11, the first rotary angle sensor 132a is supplied exclusively by the second control unit 5b, which ensures high reliability and minimizes potential fault paths on the part of the operating unit 4. The operating unit 4 can additionally include a further, third rotary angle sensor 132c, which is powered either by the first control unit 5a and / or by the second control unit 5b, thus enabling various redundancy and operating scenarios for the sensors. The roadwheel actuator 6 itself is designed for the mechanical implementation of the steering command at one or more vehicle wheels 7 and is equipped with a second steering sensor 131b and a second rotary angle sensor 132b. The output signal of this second rotary angle sensor 132b can be transmitted to the first control unit 5a of the operating unit 4, enabling mutual monitoring and plausibility checks of the current steering wheel and wheel positions. Conversely, the output signal of the first 132a and, if applicable, the third rotary angle sensor 132c can be transmitted from the operating unit 4 to the second control unit 5b, allowing for immediate evaluation and control adjustment there as well.In the illustrated embodiment, the first control unit 5a houses a first signal processing module 161a and a second signal processing module 161b, both of which are designed to power and / or evaluate the rotary angle sensors 132a and 132c installed in the operating unit 4. This allows for parallel or separate signal processing, which increases functional safety and diagnostic capability. The second control unit 5b, on the other hand, has a third signal processing module 161c, which can be configured to power and / or evaluate the first 132a and third rotary angle sensors 132c, and optionally also the second rotary angle sensor 132b. The largely identical design of the rotary angle sensors 132a, 132c installed in the control unit 4 allows for the use of uniform calibration processes and evaluation algorithms, which reduces development and production costs. Furthermore, at least one of these sensors 132a or 132c can be essentially identical to the sensor 132b located in the roadwheel actuator 6, in order to create a unified, robust sensor platform. This design reduces the integration effort because the same interfaces, components, and software components can be used for measuring and evaluating the angle signals. Figures 12-16 show various wiring and power supply scenarios for the electric motor(s) 102 of the force feedback actuator 41. The corresponding schematic representations in Figures 12-16 show the control unit 4, which serves to detect and / or provide a steering command. The control unit 4 has a steering shaft 43, through which a driver typically applies the steering torque or can feel a feedback torque. The force feedback actuator 41 is arranged at the lower end of the steering shaft 43 or on a part connected to it. In the embodiment shown in Figures 12 and 13, this force feedback actuator 41 consists of a first electric motor 102a and can also include a second electric motor 102b, as shown in the embodiments in Figures 14-16. In the example shown, the first electric motor 102a is equipped with a first winding 910a. This winding 910a serves to generate a braking torque on the steering shaft 43 by energizing it, so that the driver perceives a noticeable restoring or resistance torque. Depending on the embodiment, the first motor 102a can also have a second winding 910b, which – like the first winding 910a – can be energized to generate or increase the desired torque at the steering wheel. Alternatively or additionally, a second electric motor 102b is provided (see Figs. 14-16), which can also exert a braking or force feedback torque on the steering shaft 43. To demonstrate this functionality, a third winding 910c and, optionally, a fourth winding 910d are assigned to the second motor 102b. Each of these windings 910c, 910d can be energized individually or in combination to implement the desired control or safety strategies. Figures 12-16 further illustrate the roadwheel actuator system 6, which is responsible for the mechanical implementation of the steering command at at least one steered vehicle wheel 7. Two control units are provided for the coordinated control tasks. A first control unit 5a is assigned to the operating unit 4, and a second control unit 5b is located on the roadwheel actuator 6. In one possible configuration, the first control unit 5a comprises a first power electronics module 162a and a second power electronics module 162b. These modules are designed to selectively energize one or more of the windings 910a, 910b, 910c, 910d, thus selectively supplying motor currents. Similarly, the second control unit 5b is equipped with a third power electronics module 162c and a fourth power electronics module 162d, which are also capable of controlling the various windings or taking over control as needed. Depending on the safety and redundancy concept, each winding 910 can be controlled individually, in parallel, or exclusively by a control unit. In a scenario shown, for example, in Fig. 12, the first winding 910a can be controlled by both the first control unit 5a and the second control unit 5b. Another embodiment provides that selected windings are controlled exclusively by the second control unit 5b, for example, to ensure separation into independent control circuits, as illustrated in the embodiment shown in Fig. 13 or Fig. 16. Similarly, the second winding 910b on the first motor 102a, or the third 910c and fourth windings 910d on the second motor 102b, can be energized individually or together by either the first or the second control unit.This decentralized architecture ensures high flexibility and allows for a targeted distribution of functions between the area of ​​the control unit 4 and the area of ​​the roadwheel actuator 6. In addition, it increases operational reliability, since in the event of a local failure in one control unit, the other control unit can still intervene. It is understood that all of the aforementioned features can be combined in any meaningful way to further optimize the steer-by-wire steering system 1 and / or adapt it to given requirements. For example, it would be possible to combine features from the redundancy approach for the brake 107 power supply with features from the redundancy approach for the steering sensor 131 power supply and / or with features from the electric motor 102 power supply in any meaningful way. This is also illustrated in Fig. 17, which shows a corresponding redundancy. The invention is not limited to the embodiments illustrated in the figures. The foregoing description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features. Insofar as the claims and the foregoing description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing any hierarchy. Reference symbol list 1 Steer-by-wire steering system 2 Motor vehicle 4 Control unit 5a First control unit 5b Second control unit 6 Roadwheel actuator 7 Vehicle wheel 41 Force feedback actuator 43 Steering shaft 102 Electric motor 107a First energized brake 107b Second energized brake 108 Magnetorheological brake 117a First brake magnetic field generator 117b Second brake magnetic field generator 120a First excitation coil 120b Second excitation coil 120c Third excitation coil 120d Fourth excitation coil 131a First steering sensor 131b Second steering sensor 132a First yaw angle sensor 132b Second yaw angle sensor 132c Third yaw angle sensor 161a First signal processing module 161b Second signal processing module 161c Third signal processing module 162a First power electronics module 162b Second power electronics module 162c Third power electronics module 162d Fourth power electronics module 910 Winding (general) 910a First winding 910b Second winding 910c ThirdWinding 910d Fourth winding QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 10 2022 125 767 A1

[0005]

Claims

A steer-by-wire steering system (1) of a motor vehicle (2) comprising: • an operating unit (4) for detecting and / or providing a steering command and • a roadwheel actuator (6) for mechanically implementing the steering command at at least one vehicle wheel (7) of the motor vehicle (2), wherein the operating unit (4) comprises a force-feedback actuator (41) having at least one energizable brake (107a) with a magnetic field generating device (117a) which has at least one first energizable excitation coil (120a), wherein the magnetic field of the first excitation coil (120a) in the energized coil state acts on a steering shaft (43) of the operating unit (4) such that the latter can be subjected to a braking torque, wherein the operating unit (4) has an associated first control unit (5a) and the roadwheel actuator (6) has an associated second control unit (5b),wherein the at least first excitation coil (120a) can be energized with the first control unit (5a) of the operating unit (4) and / or with the second control unit (5b) associated with the roadwheel actuator (6), characterized in that the first energizable brake (107a) and / or the second energizable brake (107b) are directly connected to the second control unit (5b) of the roadwheel actuator (6). Steer-by-wire steering system (1) according to claim 1, characterized in that the magnetic field generating device (117) has at least one second excitation coil (120b), wherein the magnetic field of the second excitation coil (120b) acts on the steering shaft (43) of the control unit (4) in the energized coil state in such a way that the latter can be subjected to a braking torque, wherein the second excitation coil (120b) can be energized by the first control unit (5a) associated with the control unit (4) and / or by the second control unit (5b) associated with the roadwheel actuator (6). Steer-by-wire steering system (1) according to claim 1 or 2, characterized in that the first excitation coil (120a) and / or the second excitation coil (120b) can each be powered exclusively via the second control unit (5b) associated with the roadwheel actuator (6). Steer-by-wire steering system (1) according to one of the preceding claims, characterized in that the force feedback actuator (41) has at least one second energizable brake (107b) with a magnetic field generating device (117b) which has at least one third energizable excitation coil (120c), wherein the magnetic field of the third excitation coil (120c) in the energized coil state acts on a steering shaft (43) of the control unit (4) such that it can be subjected to a braking torque, wherein the third excitation coil (120c) can be energized by the first control unit (5a) associated with the control unit (4) and / or by the second control unit (5b) associated with the roadwheel actuator (6). Steer-by-wire steering system (1) according to claim 4, characterized in that the magnetic field generating device (117) of the second brake (107b) has at least one fourth excitation coil (120d), wherein the magnetic field of the fourth excitation coil (120d) in the energized coil state acts on the steering shaft (43) of the control unit (4) in such a way that it can be subjected to a braking torque, wherein the fourth excitation coil (120d) can be energized by the first control unit (5a) associated with the control unit (4) and / or by the second control unit (5b) associated with the roadwheel actuator (6). Steer-by-wire steering system (1) according to claim 4 or 5, characterized in that the third excitation coil (120c) and / or the fourth excitation coil (120d) can each be powered exclusively via the second control unit (5b) associated with the roadwheel actuator (6). Steer-by-wire steering system (1) according to one of the preceding claims, characterized in that the first control unit (5a) of the operating unit (4) is configured as a first power electronics module (162a) for energizing one of the excitation coils (120) and a second power electronics module (162b) for energizing the same and / or another of the excitation coils (120). Steer-by-wire steering system (1) according to one of the preceding claims, characterized in that the second control unit (5b) of the roadwheel actuator (6) is configured to include a third power electronics module (162c) for powering one of the excitation coils (120) and a fourth power electronics module (162d) for powering the same and / or another of the excitation coils (120). Steer-by-wire steering system (1) according to one of the preceding claims, characterized in that the first energizable brake (107a) and / or the second energizable brake (107b) are designed as a magnetorheological brake (108).

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