Steer-by-wire steering system for motor vehicles

Abstract

The present invention relates to a steer-by-wire system (1) for a motor vehicle, the steer-by-wire system (1) comprising a steering spindle (3) rotatably mounted, a feedback actuator (4) having a feedback motor (8) acting on the steering spindle (3), a steering actuator (5) having a steering motor (10) acting on a steering wheel (6) of the motor vehicle according to the rotation of the steering spindle (3), and two control units (9, 11) for controlling the feedback motor (8) and the steering motor (10). The first control unit (9) and the second control unit (11) of the two control units have different levels of complexity relative to each other, and in particular, the first control unit (9) is more efficient than the second control unit (11). The invention also relates to a method for operating the steer-by-wire system (1), wherein the first control unit (9) and the second control unit (11) execute procedures with different levels of complexity relative to each other.

Description

Background Technology

[0001] This invention relates to a steer-by-wire system for motor vehicles, comprising a steering spindle rotatably supported, a feedback actuator acting on the steering spindle, a steering actuator having a steering motor acting on the steering wheels of the motor vehicle according to the rotation of the steering spindle, and two control units for controlling the feedback motor and the steering motor. Furthermore, this invention relates to a method for operating the steer-by-wire system.

[0002] In a steer-by-wire system, the steering wheels of a motor vehicle are not mechanically connected to the steering input device or steering control device, such as the steering wheel. Therefore, the position of the steering wheel is not merely mechanically transferred to the position of the steering wheels. Instead, steering wheel rotation is transmitted via electrical signals to the corresponding deflection of the steering wheels. For this purpose, a steer-by-wire system includes: means for detecting the driver's steering input, steering wheel angle, or steering wheel rotation, particularly a steering angle sensor; means for electrically transmitting the detected driver's steering input, particularly a data cable or bus system; and means for realizing the electrically transmitted driver's steering input, particularly a steering actuator or steering controller.

[0003] It is known that control units used to control feedback motors and steering motors, particularly feedback control units and steering control units, are configured in each case to communicate with each other, i.e., exchange data. Known feedback control units and steering control units are designed to be redundant with each other, and are similar in design and function. See, for example, DE 10 2004 005 348 A1.

[0004] Therefore, the object of the present invention is to provide a more cost-effective steer-by-wire system. Advantageously, functionality should not be substantially reduced. Summary of the Invention

[0005] To achieve this objective, a steer-by-wire system for motor vehicles and a method for operating the steer-by-wire system are proposed according to the present invention. The exemplary embodiments illustrated in the specification and drawings produce advantageous improvements.

[0006] The proposed steer-by-wire system includes a rotatably supported steering spindle, a feedback actuator with a feedback motor acting on the steering spindle, a steering actuator with a steering motor acting on the steering wheels of the vehicle according to the rotation of the steering spindle, and two control units for controlling the feedback motor and the steering motor. The first and second control units of the two control units have different levels of complexity relative to each other. Specifically, the two control units can be configured as a feedback control unit for controlling the feedback motor and a steering control unit for controlling the steering motor. According to an advantageous design, the feedback actuator includes the feedback control unit. According to another advantageous design, the steering actuator includes the steering control unit.

[0007] Advantageously, the first control unit and the second control unit are connected to each other for signal exchange, i.e., particularly by means of communication technology. Specifically, the first control unit can be configured to send signals to and receive signals from the second control unit. Furthermore, the second control unit can be specifically configured to send signals to and receive signals from the first control unit. Advantageously, both the first and second control units have communication interfaces. Specifically, the first and second control units can be configured to communicate via a communication bus. Signal transmission between the first and second control units can be wired and / or wireless.

[0008] Because control units have varying levels of complexity, steer-by-wire systems can be designed so that specific tasks can be assigned to each control unit. Each control unit can be selected, sized, or configured according to its requirements within the steer-by-wire system. This results in a cost advantage, as the control units do not necessarily have equal power, but one control unit can advantageously have significantly less power than the other. In particular, in the case of a communication connection between the first and second control units, the execution steps for generating control signals, especially the computational operations, can advantageously be transferred from one control unit to the other.

[0009] The feedback actuator in a steer-by-wire system is specifically designed to introduce torque into the steering spindle, where the torque depends on the mechanical loads acting on the wheels of the steering vehicle. These mechanical loads include, for example, the friction between the vehicle wheels and the road, which depends on the road surface and ground conditions, as well as shocks caused by bumps and potholes.

[0010] The steering actuator in a steer-by-wire system is specifically designed to adjust the angle of the vehicle wheels based on the rotation of the steering spindle, i.e., according to steering commands.

[0011] Advantageously, the first control unit and the second control unit have different levels of software complexity and / or hardware complexity relative to each other. The term software includes the terms computer programs and source code.

[0012] Software complexity can be defined as a metric-based measure, where a metric is a function applicable to the software that quantifies the software in the form of a measure, where the measure represents a software attribute. The quantification function is specifically a mathematical function. Software attributes specifically include the size of the source code, preferably the number of lines or characters, the functional scope of the source code, the maintainability of the source code, the extensibility of the source code, and / or the understandability of the source code. Examples include the Chapins data metric, the Elshofs data flow metric, the Cards data access metric, the Henrys interface metric, the McCabe metric or cyclomatic complexity, the McClure's decision metric, the Sneeds branching metric, and the Halstead metric.

[0013] Alternatively, software complexity can be defined as a measure of the algorithmic information content of the software. Examples of this include Kolmogorov complexity, algorithmic complexity, or descriptive complexity. Further alternatively, software complexity can be defined as a measure of the software's resource consumption, particularly the number of computational operations, computation time, storage space, and / or power consumption. Even further alternatively, software complexity can be defined as a measure of the software's functional scope, particularly its functionality, the number of possible input signals, and / or the number of possible output signals. It is also conceivable and possible to define software complexity as a combination of two or more of the foregoing definitions.

[0014] Hardware complexity can be defined as a measure of the number of components within the control unit, particularly storage units, switches, filters, and computing units, especially processors. Specifically, it can be configured that the first control unit includes more powerful hardware than the second control unit.

[0015] In a further advantageous manner, the different levels of complexity of the first control unit and the second control unit are formed by their different computing capabilities or computing efficiencies. An advantageous design configuration is that the first control unit includes a first computing unit, and the second control unit includes a second computing unit, wherein the first computing unit is designed to perform more computational operations per unit time compared to the second computing unit. This results in a cost advantage relative to the second control unit.

[0016] Furthermore, advantageously, the first control unit can be configured to execute high-level software, while the second control unit is designed to execute low-level software. Specifically, the second control unit is not designed to execute high-level software. This also allows for a more cost-effective implementation of the second control unit.

[0017] Another advantageous embodiment involves a first control unit participating in determining motor control signals for controlling the feedback motor and the steering motor, and a second control unit participating in determining motor control signals for controlling either the feedback motor or the steering motor. Specifically, the second control unit performs only lower-level operations compared to the first control unit. Advantageously, the second control unit, having lower power consumption than the first control unit, processes the received signals, particularly those from angle sensors, torque sensors, current measurement signals, and / or voltage signals. In particular, analog-to-digital conversion of these signals can be provided by the second control unit. The signals are then advantageously transmitted from the second control unit to the first control unit for further use, particularly further processing. Advantageously, the first control unit is also designed to process the received signals, particularly those from angle sensors, torque sensors, current measurement signals, and / or voltage signals, and specifically to convert analog signals into digital signals. These signals, as well as the signals transmitted by the second control unit, are advantageously processed by the first control unit, particularly for generating control signals for the feedback motor of the feedback actuator and the steering motor of the steering actuator.

[0018] Specifically, the first control unit can be configured to: receive a first sensor signal, particularly from at least one angle sensor and / or at least one torque sensor; process the first sensor signal, particularly by analog-to-digital conversion; and determine a first motor control signal from the processed first sensor signal. Depending on the allocation of the first control unit and the second control unit, the first motor control signal is either a control signal for the feedback motor of a feedback actuator or a control signal for the steering motor of a steering actuator. The second control unit is advantageously configured to: receive a second sensor signal, particularly from at least one additional angle sensor and / or at least one additional torque sensor; process the second sensor signal, particularly by analog-to-digital conversion; and forward the processed second sensor signal to the first control unit. Advantageously, the first control unit is further developed to receive the processed second sensor signal and determine a second motor control signal from the processed second sensor signal. Depending on the allocation of the first control unit and the second control unit, the second motor control signal is either a control signal for the steering motor of a steering actuator or a control signal for the feedback motor of a feedback actuator. Further advantageously, the first control unit is also configured to forward the determined second motor control signal to the second control unit. The second control unit is specifically designed to receive and provide the second motor control signal for controlling the steering motor of the steering actuator or the feedback motor of the feedback actuator.

[0019] It can be configured that the first control unit also takes over the functions of the second control unit in the event of a failure of the second control unit. Specifically, it can be configured that, in this case, the first control unit controls both the feedback motor of the feedback actuator and the steering motor of the steering actuator.

[0020] According to one embodiment, a first control unit may be configured to control a feedback motor, and a second control unit may be configured to control a steering motor. Advantageously, the first control unit includes feedback platform software, feedback application software, and control application software. The second control unit specifically includes steering platform software. In particular, the second control unit does not include any feedback platform software, any feedback application software, or any steering application software.

[0021] In a design variation, the first control unit is designed to control the steering motor, and the second control unit is designed to control the feedback motor. Advantageously, the first control unit includes steering platform software, steering application software, and feedback application software. The second control unit specifically includes feedback platform software. In particular, the second control unit does not include any steering platform software, any steering application software, or any feedback application software.

[0022] The feedback platform software and steering platform software are advantageously designed to implement hardware-dependent, remotely controlled commands. The feedback application software and steering application software are advantageously designed to implement hardware-remote, user-oriented commands. Specifically, the feedback platform software and steering platform software can be configured as low-level software. Furthermore, the feedback application software and steering application software can be specifically configured as high-level software.

[0023] In embodiments where the control units take the form of feedback control units and steering control units, the feedback control unit has a lower level of complexity compared to the steering control unit. The feedback control unit can be designed to perform tasks within a smaller and / or less computationally intensive task range. On the other hand, the steering control unit can be designed to perform tasks within a larger and / or more computationally intensive task range.

[0024] Advantageously, the feedback control unit includes feedback platform software, and the steering control unit includes steering platform software and steering application software.

[0025] The feedback platform software and steering platform software can each be designed to implement hardware-dependent, remotely controlled commands from the steering control unit. Both can be lower-level software in terms of architecture than the application software, particularly the steering application software. The hardware-dependent, remotely controlled commands from the steering control unit can be implemented using sensor values ​​representing steering commands, specifically steering angle and steering torque. Calculation of the steering torque and control of the steering motor based on that torque are also specifically provided.

[0026] Steering application software can be designed to implement remote, user-oriented commands from the steering control unit hardware. Steering application software can be software with a higher level of software architecture than platform software, especially feedback platform software and steering platform software.

[0027] According to another embodiment, the steering control unit has a lower level of complexity compared to the feedback control unit. The steering control unit can be designed to perform tasks within a smaller and / or less computationally intensive task range. On the other hand, the feedback control unit can be designed to perform tasks within a larger and / or more computationally intensive task range.

[0028] Advantageously, the steering control unit includes steering platform software, and the feedback control unit includes feedback platform software and feedback application software.

[0029] The steering platform software and feedback platform software can each be designed to implement hardware-dependent, remotely controlled commands from the feedback control unit. Both can be lower-level software in terms of software architecture than the application software, especially the feedback application software. The hardware-dependent, remotely controlled commands from the feedback control unit can be implemented based on sensor values ​​representing the mechanical loads acting on the vehicle wheels, particularly force and torque. Calculation of feedback torque and control of the feedback motor based on the feedback torque are also specifically provided.

[0030] Feedback application software can be designed to implement remote, user-oriented commands from the feedback control unit. Feedback application software can be software with a higher level of software architecture than platform software, especially steering platform software and feedback platform software.

[0031] The feedback control unit and the steering control unit are preferably designed to exchange information. The feedback control unit and the steering control unit preferably exchange information via an information interface.

[0032] Further advantageously, the first control unit may be configured to have an interface for connecting the first control unit to the communication bus of the motor vehicle. Of the first and second control units, advantageously, only the first control unit is designed to exchange signals via the communication bus, particularly with other control units and / or other signaling devices of the motor vehicle.

[0033] Additionally, preferably, the feedback motor and the steering motor each have one or more coils.

[0034] A method for operating a steer-by-wire system, particularly a steer-by-wire system according to the invention, is configured such that a first control unit and a second control unit execute programs with different levels of complexity relative to each other, and this method is also proposed to achieve the objectives of the invention. Specifically, the feedback control unit and the steering control unit are configured as control units, wherein the feedback control unit and the steering control unit execute programs with different levels of complexity relative to each other.

[0035] According to one implementation, the steering control unit performs all calculations of the feedback control unit and the steering control unit, wherein the feedback control unit receives and executes the results calculated by the steering control unit.

[0036] According to another embodiment, the feedback control unit performs all calculations of the steering control unit and the feedback control unit, wherein the steering control unit receives and executes the results calculated by the feedback control unit.

[0037] Specifically, it can be configured that the first control unit performs all calculations for determining the first motor control signal and all calculations for determining the second motor control signal. Advantageously, the first control unit forwards the calculation results for determining the second motor control signal to the second control unit. The second control unit, specifically, does not perform these calculations—that is, it does not perform all calculations for determining the first motor control signal and all calculations for determining the second motor control signal—but advantageously receives the calculation results for determining the second motor control signal and provides the second motor control signal specifically for controlling a feedback motor or a steering motor.

[0038] According to an advantageous embodiment of the invention, a first control unit receives a first sensor signal, advantageously processes the first sensor signal, and advantageously determines a first motor control signal from the processed first sensor signal. A second control unit advantageously receives a second sensor signal. Specifically, the second control unit processes the received sensor signal and advantageously forwards the processed second sensor signal to the first control unit. Further advantageously, the first control unit then receives the processed second sensor signal and advantageously determines a second motor control signal from the processed second sensor signal. Advantageously, the first control unit then forwards the determined second motor control signal to the second control unit. The second control unit then advantageously uses the received second motor control signal to control a feedback motor or a steering motor. Using the first motor control signal, the first control unit advantageously controls the steering motor or the feedback motor.

[0039] Specifically, as one implementation, a first control unit may be assigned to the feedback actuator, and a second control unit may be assigned to the steering actuator, wherein the first motor control signal is a signal for controlling the feedback motor, and the second motor control signal is a signal for controlling the steering motor.

[0040] In another embodiment, a first control unit may be assigned to the steering actuator, and a second control unit may be assigned to the feedback actuator, wherein the first motor control signal is a signal for controlling the steering motor, and the second motor control signal is a signal for controlling the feedback motor. Attached Figure Description

[0041] The advantageous embodiments and details of the embodiments of the present invention will now be described in more detail with reference to the accompanying drawings (Figure: Drawings). In the drawings, in detail:

[0042] Figure 1 An embodiment of the steer-by-wire system according to the present invention is illustrated in a three-dimensional schematic diagram.

[0043] Figure 2 It is shown in a greatly simplified block diagram form. Figure 1 The steer-by-wire steering system, and

[0044] Figure 3 a, Figure 3 Each of the b's represents another embodiment of the steer-by-wire system according to the invention, presented in a greatly simplified block diagram. Detailed Implementation

[0045] In different accompanying drawings, the same parts are always given the same reference numerals and are therefore usually named or mentioned only once.

[0046] Figure 1 An embodiment of the steer-by-wire system 1 designed according to the present invention is shown in a three-dimensional schematic diagram viewed from the oblique front of the vehicle's direction of travel, wherein non-essential components are not shown in order to provide an improved overview of the description of the invention.

[0047] A steer-by-wire system 1, suitable for motor vehicles, particularly passenger cars, includes a steering column 2, a feedback actuator 4, and a steering actuator 5. A steering spindle 3 is rotatably supported in the steering column 2. The feedback actuator 4 acts on the steering spindle 3, and the steering actuator 5 acts on the steering wheels 6 of the motor vehicle according to the rotation of the steering spindle 2. A steering wheel 7 for inputting steering input to the driver is attached to the driver-facing end of the steering spindle 3. The feedback actuator 4 has a feedback motor 8 and a feedback control unit 9 for controlling the feedback motor 8. The steering actuator 5 has a steering motor 10 and a steering control unit 11 for controlling the steering motor 10.

[0048] To facilitate data exchange between the feedback actuator 4, particularly the feedback control unit 9, and the steering actuator 5, particularly the steering control unit 11, a data transmission device 12, in the form of a data cable, connects the feedback actuator 4 to the steering actuator 5. The data transmission device 12 transmits data bidirectionally; that is, it transmits data both from the feedback actuator 4 along the direction of the steering actuator 5 (steering input direction) and from the steering actuator 5 along the direction of the feedback actuator 4 (feedback direction).

[0049] In the direction of steering input, the driver's steering input can be detected by sensors on or within the steering column 2. The sensor data is specifically related to the steering angle and steering torque. The sensor data can be transmitted via data transmission device 12 to the steering actuator 5, which serves as the final control element.

[0050] Belt drive 13 is connected to and arranged on steering actuator 5. Belt drive 13 includes a belt drive pulley 14, a belt output pulley 15, and a drive belt 16 connecting the belt drive pulley 14 to the belt output pulley 15, i.e., mechanically coupling it. The drive belt 16 is a toothed belt, although other types of belts, such as flat belts or V-belts, may also be used. The belt output pulley 15 is torsionally connected to a helical gear for converting rotary motion into translational motion. The helical gear is a ball screw, although other types of helical gears may also be used.

[0051] The steering motor 10 rotates the drive pulley 14, causing the drive pulley 14 to rotate the output pulley 15 via the drive belt 16. The output pulley 15 then causes the connecting rod 17 to translate along its longitudinal axis via a helical gear. The connecting rod 17, which moves linearly along its longitudinal axis, is mechanically connected to tie rods 18 located on both sides of the vehicle. The tie rods 18 are in turn mechanically connected to the vehicle wheels 6. Due to the described electromechanical connections, the driver's steering input can be transmitted to the vehicle wheels 6.

[0052] In the direction of feedback, mechanical information can be detected by sensors on or within the steering actuator 5, belt gearbox 13, helical gearbox, connecting rod 17, tie rod 18, and / or vehicle wheels 6. This information may include, for example, vibrations on the aforementioned structures caused by the ripples, potholes, and / or roughness of the road 19 during driving, as well as mechanical resistance generated by the road surface, road inclination, and / or turning during steering. By means of tactile or sensory feedback, i.e., by applying torque corresponding to the mechanical information (feedback torque) to the steering spindle 3, the driver can obtain an impression of the condition of the road surface.

[0053] The feedback control unit 9 and the steering control unit 11 have different levels of complexity relative to each other.

[0054] Figure 2 It is shown in a greatly simplified block diagram form. Figure 1 1. Steer-by-wire steering system.

[0055] Such as combination Figure 1 As described, the steer-by-wire system 1 includes a feedback actuator 4 and a steering actuator 5, wherein the feedback actuator 4 includes a feedback motor 8 and a feedback control unit 9, and wherein the steering actuator 5 includes a steering motor 10 and a steering control unit 11.

[0056] Feedback motor 8 is used to introduce feedback torque to areas not in use. Figure 2 The steering spindle 3 is shown in the diagram. The feedback actuator 4 also includes a feedback inverter 20 and a feedback sensor 21. The feedback inverter 20 electrically connects the feedback motor 8 and the feedback control unit 9 to each other and serves as an intermediate power stage when the feedback motor 8 is controlled by the feedback control unit 9. The feedback sensor 21 is configured to monitor the state of the feedback motor 8 and transmit information about the state of the feedback motor 8 to the feedback control unit 9.

[0057] The steering motor 10 generates the driver's steering input torque, which corresponds to the torque detected by the sensor. The generated driver steering input torque is converted into linear motion of the connecting rod 17 via a mechanical connection between the drive wheel 14 and the connecting rod 17. Since the connecting rod 17 is mechanically connected to the steering wheel 6, the wheel 6 steers according to the driver's steering input. The steering actuator 5 also includes a steering inverter 22 and a steering sensor 23. The steering inverter 22 electrically connects the steering motor 10 and the steering control unit 11 to each other and serves as an intermediate power stage when the steering motor 10 is controlled by the steering control unit 11. The steering sensor 23 is configured to monitor the state of the steering motor 10 and transmit information about the state of the steering motor 10 to the steering control unit 11.

[0058] Feedback control unit 9 and steering control unit 11 are each designed to exchange information via information interface 24. Feedback control unit 9 receives first signals from a torque sensor (not explicitly shown) and a rotation angle sensor (also not explicitly shown). Feedback control unit 9 processes these first signals and determines a control signal for feedback motor 8 from the processed first signals. Steering control unit 11 receives second signals from a torque sensor (also not explicitly shown) and a rotation angle sensor (also not explicitly shown). Steering control unit 11 processes the received second signals and forwards the received second signals to feedback control unit 9 via information interface 24. Feedback control unit 9 receives the processed second signals via information interface 24 and determines a control signal for controlling steering motor 10 from these signals. Feedback control unit 9 forwards the control signal for controlling steering motor 10 to steering control unit 11 via information interface 24, and steering control unit 11 receives the control signal for controlling steering motor 10. Steering control unit 11 uses the received control signal for controlling steering motor 10 to control steering motor 10. Feedback control unit 9 uses the determined control signal for feedback motor 8 to control feedback motor 8. The steering control unit 11 has a lower level of complexity than the feedback control unit 9 because the steering control unit 11 itself is not designed to determine the control signal used to control the steering motor 10.

[0059] Figure 3 a) shows another embodiment of the steer-by-wire system 1 according to the invention in a highly simplified block diagram form.

[0060] Such as combination Figure 1 and Figure 2 The described steer-by-wire system 1 includes a feedback control unit 9 and a steering control unit 11. The feedback control unit 9 and the steering control unit 11 are each designed to exchange information via an information interface 24.

[0061] Compared to known steer-by-wire systems—in which the feedback control unit and steering control unit have essentially the same complexity in design and function, particularly in software complexity, and both have application software and platform software—the feedback control unit 9 and steering control unit 11 have different levels of software complexity relative to each other. The feedback control unit 9 has a lower level of software complexity than the steering control unit 11. The feedback control unit 9 includes feedback platform software 25. On the other hand, the steering control unit 11 includes both steering application software 26 and steering platform software 27. The feedback platform software 25 and steering platform software 27 are each designed to implement hardware-dependent, user-remote commands. For this purpose, the feedback platform software 25 and steering platform software 27 are each designed to implement the commands of the steering application software 26. The steering application software 26 is designed to implement hardware-remote, user-oriented commands. In particular, the steering application software 26 also includes the functionality of the feedback application software, enabling advantageous calculation of signals for controlling the feedback motor 8. Compared to known steer-by-wire systems—where each control unit has its own application software tailored to the requirements of that control unit—steering application software 26 serves as a shared application software for both feedback actuator 4 and steering actuator 5. Since the two control units 9 and 11 are connected to each other via information interface 24, only a single application software is required, namely, steering application software 26 in this version.

[0062] Figure 3 b) shows another embodiment of the steer-by-wire system 1 according to the invention in a highly simplified block diagram form.

[0063] The feedback control unit 9 and the steering control unit 11 have different levels of software complexity relative to each other. The steering control unit 11 has a lower level of software complexity than the feedback control unit 9. The steering control unit 11 includes steering platform software 27. On the other hand, the feedback control unit 9 includes both feedback platform software 25 and feedback application software 28. The feedback platform software 25 and the steering platform software 27 are each designed to implement hardware-dependent, user-remote commands. For this purpose, the feedback platform software 25 and the steering platform software 27 are each designed to implement the commands of the feedback application software 28. The feedback application software 28 is designed to implement hardware-remote, user-oriented commands. In particular, the feedback application software 28 also includes the functions of the steering application software, which advantageously calculates the signals used to control the steering motor 10. Compared to known steer-by-wire systems—in which each control unit has its own application software adapted to the requirements of the respective control unit—the feedback application software 28 serves as the common application software for the feedback actuator 4 and the steering actuator 5. Since the two control units 9 and 11 are connected to each other via information interface 24, only a single application software is needed, namely, feedback application software 28 in this version.

[0064] List of reference numerals

[0065] 1. Steer-by-wire steering system

[0066] 2 steering columns

[0067] 3 steering spindles

[0068] 4 Feedback Actuators

[0069] 5 steering actuators

[0070] 6 vehicle wheels

[0071] 7-wheel steering wheel

[0072] 8 feedback motors

[0073] 9 Feedback Control Unit

[0074] 10 steering motors

[0075] 11 Steering Control Unit

[0076] 12 Data Transmission Devices

[0077] 13 Belt Drive Device

[0078] 14 with drive wheels

[0079] 15 with output wheel

[0080] 16 drive belt

[0081] 17 connecting rods

[0082] 18-bar tie rod

[0083] 19th Road

[0084] 20 Feedback Inverter

[0085] 21 Feedback Sensors

[0086] 22-way inverter

[0087] 23 Steering Sensors

[0088] 24 Information Interfaces

[0089] 25 Feedback Platform Software

[0090] 26 Steering Application Software

[0091] 27 Steering Platform Software

[0092] 28 Feedback Application Software

Claims

1. A steer-by-wire system (1) for a motor vehicle, comprising a steering spindle (3) rotatably supported, a feedback actuator (4) having a feedback motor (8) acting on the steering spindle (3), a steering actuator (5) having a steering motor (10) acting on a steering wheel (6) of the motor vehicle according to rotation of the steering spindle (3), and two control units (9, 11) for controlling the feedback motor (8) and the steering motor (10), characterized in that, The first control unit (9) and the second control unit (11) of the two control units have different levels of complexity relative to each other; The first control unit (9) is designed to receive a first sensor signal, process the first sensor signal, and determine a first motor control signal from the processed first sensor signal. The second control unit (11) is designed to receive the second sensor signal, process the second sensor signal, and forward the processed second sensor signal to the first control unit (9). Furthermore, the first control unit (9) is also designed to receive the processed second sensor signal and determine the second motor control signal from the processed second sensor signal.

2. The steer-by-wire system (1) according to claim 1, characterized in that, The first control unit (9) and the second control unit (11) have different levels of software complexity and / or hardware complexity.

3. The steer-by-wire system (1) according to claim 1 or claim 2, characterized in that, The first control unit (9) and the second control unit (11) are connected to each other for signal exchange.

4. The steer-by-wire system (1) according to any one of claims 1-2, characterized in that, The first control unit (9) includes more powerful hardware than the second control unit (11).

5. The steer-by-wire system (1) according to claim 4, characterized in that, The first control unit (9) includes a first computing unit, and the second control unit (11) includes a second computing unit, wherein the first computing unit is designed to perform more computing operations per unit time than the second computing unit.

6. The steer-by-wire system (1) according to any one of claims 1-2, characterized in that, The first control unit (9) is designed to execute high-level software, and the second control unit (11) is designed to execute low-level software.

7. The steer-by-wire system (1) according to any one of claims 1-2, characterized in that, The first control unit (9) participates in determining the motor control signal for controlling the feedback motor (8) and the steering motor (10), and the second control unit (11) participates in determining the motor control signal for controlling the feedback motor (8) or the steering motor (10).

8. The steer-by-wire system (1) according to claim 7, characterized in that, The first control unit (9) is also designed to forward the determined second motor control signal to the second control unit (11).

9. The steer-by-wire system (1) according to any one of claims 1-2, characterized in that, The first control unit (9) is designed to take over the functions of the second control unit (11) in the event of a failure of the second control unit (11).

10. The steer-by-wire system (1) according to any one of claims 1-2, characterized in that, The first control unit (9) is designed to control the feedback motor (8), and the second control unit (11) is designed to control the steering motor (10).

11. The steer-by-wire system (1) according to claim 10, characterized in that, The first control unit (9) includes feedback platform software (25), feedback application software (28), and steering application software (26), and the second control unit includes steering platform software (27), wherein the feedback platform software (25) and the steering platform software (27) are each designed to implement hardware-oriented, user-remote instructions, and wherein the feedback application software (28) and the steering application software (26) are each designed to implement hardware-remote, user-oriented instructions.

12. The steer-by-wire system (1) according to any one of claims 1 to 2, characterized in that, The first control unit (9) is designed to control the steering motor (10), and the second control unit (11) is designed to control the feedback motor (8).

13. The steer-by-wire system (1) according to claim 12, characterized in that, The first control unit (9) includes steering platform software (27), steering application software (26), and feedback application software (28), and the second control unit includes feedback platform software (25), wherein the feedback platform software (25) and the steering platform software (27) are each designed to implement hardware-related, user-remote instructions, and wherein the feedback application software (28) and the steering application software (26) are each designed to implement hardware-remote, user-oriented instructions.

14. The steer-by-wire system (1) according to any one of claims 1-2, characterized in that, The first control unit (9) has an interface for connecting the first control unit (9) to a communication bus of a motor vehicle, wherein, of the first control unit (9) and the second control unit (11), only the first control unit (9) is designed to exchange signals via the communication bus.

15. A method for operating a steer-by-wire system (1) according to any one of claims 1-14, characterized in that, The first control unit (9) and the second control unit (11) execute programs with different complexities relative to each other; The first control unit (9) receives a first sensor signal, processes the first sensor signal, and determines a first motor control signal from the processed first sensor signal. The second control unit (11) receives the second sensor signal, processes the second sensor signal, and forwards the processed second sensor signal to the first control unit (9). Furthermore, the first control unit (9) receives the processed second sensor signal and determines the second motor control signal from the processed second sensor signal.

16. The method according to claim 15, characterized in that, The first control unit (9) performs all calculations for determining the first motor control signal and all calculations for determining the second motor control signal. The first control unit (9) forwards the calculation results for determining the second motor control signal to the second control unit. The second control unit (11) does not perform these calculations, but receives the calculation results for determining the second motor control signal and provides the second motor control signal.

17. The method according to claim 16, characterized in that, The first control unit (9) forwards the determined second motor control signal to the second control unit (11).

18. The method according to any one of claims 15-16, characterized in that, The first control unit (9) is assigned to the feedback actuator (4), and the second control unit (11) is assigned to the steering actuator (5), wherein the first motor control signal is a signal for controlling the feedback motor (8), and the second motor control signal is a signal for controlling the steering motor (10); Alternatively, the first control unit (9) is assigned to the steering actuator (5), and the second control unit (11) is assigned to the feedback actuator (4), wherein the first motor control signal is a signal for controlling the steering motor (10), and the second motor control signal is a signal for controlling the feedback motor (8).

Images