Steering wheel actuator device and operating system of steering-by-wire system of motor vehicle

Abstract

The invention proposes a steering wheel actuator arrangement (110, 210) for a steer-by-wire system (105) of a motor vehicle (100). The invention relates to a steering wheel actuator device (210), comprising at least one steering wheel angle measuring device (211) for measuring a steering wheel angle of a steering wheel (140), an adjustment motor device (212) for generating an adjustment motor torque that counteracts a driver torque applied to the steering wheel (140), and a control device (219), the steering wheel actuator device (210) being connectable to an electrical energy source (250), the electrical energy source (250) supplies electrical energy to the steering wheel actuator device (210) at least during normal operation, and wherein the actuator device (210) further has an electrical energy storage device (216) which is chargeable to a limit value and is configured to store electrical energy to the steering wheel actuator device (210) during abnormal operation when the steering wheel actuator device (210) is not supplied with electrical energy by the electrical energy source (250). The stored electrical energy is supplied to at least one steering wheel angle measuring device (211). The electrical energy storage device (216) may preferably be charged with electrical energy generated by the conditioning motor device (212) when the applied driver torque exceeds the conditioning motor torque.

Description

Technical Field

[0001] The invention relates to a steering wheel actuator device for a steer-by-wire system of a motor vehicle, a steer-by-wire system, a motor vehicle and a suitable method for operating a steering wheel actuator device. Background Art

[0002] For normal control of the motor vehicle, the driver changes the alignment of the steerable wheels of the motor vehicle in contact with the road. To this end, the driver uses a steering wheel, the changes in the steering angle or rotation angle of the steering wheel are converted into changes in the angle of the steering wheel relative to the road. To this end, a mechanical connection can be established between the steering wheel operated by the driver and the steering wheel of the motor vehicle, for example, by means of a steering column and a steering rod. In turn, a steer-by-wire system captures a steering command or corresponding steering angle information by means of one or more sensors, in particular at least one steering wheel angle sensor, and transmits this command exclusively to an electromechanical actuator via an electrical connection (possibly with the aid of one or more control devices), which executes the steering command and modifies the alignment of the steering wheel accordingly. To this end, a steer-by-wire system has a feedback actuator device, that is, a steering wheel actuator device connected to the vehicle steering wheel, and a wheel actuator device, that is, an axle actuator device, which is electrically connected to the steering wheel actuator device and controls the angle of the steering wheel relative to the road. The steering wheel actuator device is used to measure the steering wheel angle set by the driver and generate a regulating motor torque suitable for the current driving situation through a regulating motor (that is, the driver's feedback torque, which offsets the driver torque applied to the steering wheel by the driver). The axle actuator device moves the steering wheel to the desired position through other regulating motors.

[0003] Since the steering system of a vehicle is a safety-relevant vehicle system, it is necessary to ensure the safe, uninterrupted availability of the control functions of the steer-by-wire system. A fault in the electrical communication between the steering wheel actuator device and the axle actuator device or a fault in the steering wheel angle measurement would mean a loss of controllability of the vehicle. The uncontrollability of the regulating motor of the steering wheel actuator device could result in the driver torque no longer being generated, so that under certain circumstances the driver could turn the steering wheel more or less effortlessly. In particular, when this type of fault state is detected, if no damping for safety purposes is achieved by an appropriate design of the steering wheel actuator, large steering wheel angle changes could be inadvertently performed, resulting in an unnecessarily large setting angle of the counterwheel of the motor vehicle.

[0004] Thus, the steer-by-wire system may provide redundant components, for example using multiple sensors for angle measurement, multiple steering wheel actuator devices, multiple axle actuator devices, or in particular using multiple external electrical energy sources connected to the steering wheel actuator devices and / or the axle actuator devices.

[0005] DE 100 53 335 A1 describes a steer-by-wire system for a motor vehicle in which all essential devices are provided multiple times. The power supply of the system also provides a connection to multiple batteries.

[0006] US 2002 / 0005315 A1 describes a steering wheel system which supports steer-by-wire operation and provides additional damping of steering wheel movements in the event of a steering wheel actuator failure.

[0007] WO 2019 / 179859 A1 describes a steer-by-wire system in which a steering wheel actuator arrangement and an axle actuator arrangement are connected together to two redundant power supplies.

[0008] WO 2019 / 243300 A1 proposes a steer-by-wire system in which an axle actuator is connected to two redundant power supplies, wherein a feedback actuator is similarly connected to one of the power supplies, and the system also has another steering angle sensor connected to the other power supply.

[0009] DE 20 2014 100 980 U1 describes a drive system in which a DC motor is switched to a short-circuit state in response to a sudden power failure to generate a resistive torque, wherein the short-circuit transistor used is powered by an auxiliary power supply.

[0010] Since the electrical energy supply is usually provided by the vehicle battery, providing redundancy is costly and, moreover, from a safety point of view, it cannot always be ensured that the energy sources are independent of each other. Summary of the invention

[0011] The object of the present invention is to provide a low-cost alternative for ensuring the steering availability of a motor vehicle with a steer-by-wire system even in the event of a failure or partial interruption of the normal electrical energy supply.

[0012] This object is achieved according to the invention by a steering wheel actuator device for a steer-by-wire system for a motor vehicle according to claim 1, a steer-by-wire system for a motor vehicle according to claim 11, a motor vehicle according to claim 12 and a method for operating a steering wheel actuator device for a steer-by-wire system for a motor vehicle according to claim 13. Advantageous developments of the invention are indicated in the dependent claims.

[0013] According to a first aspect of the invention, a steering wheel actuator device for a steer-by-wire system of a motor vehicle comprises at least one steering wheel angle measuring device for measuring a steering wheel angle of a steering wheel, a regulating motor device for generating a regulating motor torque for counteracting a driver torque applied to the steering wheel, and a control device. The steering wheel actuator device is connectable to an electrical energy source, which supplies electrical energy to the steering wheel actuator device at least during normal operation. It can be provided that the steering wheel actuator device also has an electrical energy storage device, which can be charged to a limit value and is configured to supply stored electrical energy to at least at least one steering wheel angle measuring device during abnormal operation when the steering wheel actuator device is not supplied with electrical energy by the electrical energy source.

[0014] The steering wheel angle refers to the rotation angle of the steering wheel turned by the driver around its rotation axis. The steering wheel angle measuring device has a steering wheel angle sensor and any control circuit that may be required. The regulating motor device includes a regulating motor (for example, a DC motor, which is preferably designed to be brushless due to lower mechanical friction), and one or more switch modules for switching the phases of the regulating motor. The switch module is composed of activatable semiconductor switching elements, such as field effect transistors and / or thyristors. The control device (for example, a programmable device, such as a processor or a microcontroller) is configured to transmit an activation signal to the switch module to control the current operating state of the regulating motor. According to an embodiment of the steering wheel angle measuring device, it can be further provided that the control device receives a steering wheel angle signal from the steering wheel angle measuring device, processes the signal and also transmits the signal or a related steering command to the axle actuator device.

[0015] The electrical energy source is a current source or a voltage source (e.g. a vehicle battery) and is provided for supplying electrical energy to at least the steering wheel actuator device during normal operation (i.e. during routine operation without faults). Abnormal operation may occur if the electrical energy source is disconnected, turned off or interrupted so that the electrical energy source cannot normally supply electrical energy to the steering wheel actuator device.

[0016] For this abnormal operation, the steering wheel actuator device is equipped with a dedicated internal energy storage device, which for example comprises a storage capacitor and is able to supply stored electrical energy to at least at least one steering wheel angle measuring device even if the (main) electrical energy source is not available. This ensures at least a continuous measurement of the steering wheel angle, without which the motor vehicle would no longer be controllable. If only the measurement of the steering wheel angle is ensured, the steering wheel angle measuring device is designed to transmit the steering wheel angle or a steering command related thereto directly to the axle actuator device. The electrical energy storage device can be charged to a limit value, when which limit value is reached, it is ensured that there is sufficient energy for at least temporary continuous operation of at least the steering wheel angle measuring device. The limit value can be a maximum value, that is, it can specify the maximum storable amount of electrical energy.

[0017] In this way, if the energy source actually provided during normal operation is lost, at least a sudden failure of the steering can be prevented, wherein if the energy is only used, for example, to ensure that the vehicle can be parked safely, the size of the energy storage device can be chosen to be very small and therefore very cost-effective.

[0018] In one embodiment, the steering wheel actuator device is configured such that during abnormal operation the electrical energy storage device also supplies stored electrical energy to at least the control device. In this embodiment, it can be provided that the steering wheel angle measuring device is supplied with energy by the control device. The electrical energy storage device is dimensioned such that it can also supply electrical energy to the control device, thereby ensuring at least the continuity of the steering angle measurement.

[0019] In another embodiment of the steering wheel actuator device, the regulating motor device is configured to generate electrical energy in a generator operating state when the applied driver torque exceeds the regulating motor torque (i.e., counteracts and exceeds its amount). In this way, electrical energy can be generated in the steering wheel actuator device regardless of the availability of an external electrical energy source. The generator operating state is one of a plurality of possible operating states of the regulating motor device and can be adopted during normal and abnormal operation of the steering wheel actuator device. During normal operation of the steering wheel actuator device, in which an external electrical energy source is also available, the regulating motor device can also be operated in a motor operating state in which the applied driver torque does not exceed the regulating motor torque, thereby consuming electrical energy. Since the internal electrical energy storage device is intended to represent a low-cost safety solution, there is no limitation on the size of the internal electrical energy storage device to enable it to permanently enable normal operation of the steering wheel actuator device even in the absence of an external electrical energy source. During abnormal operation of the steering wheel actuator device, an operating state of the regulating motor device can also be obtained in which possible steering wheel movements are damped.

[0020] In an exemplary embodiment, the steering wheel actuator device is configured to cause the electrical energy generated in the generator operating state to be at least partially stored in the electrical energy storage device when the state of charge of the electrical energy storage device is below a limit value. In other words, the electrical energy storage device can be charged in this way even during abnormal operation by steering movements (that is, the driver turning the steering wheel). Even if the steering is powered off and no longer ready for operation, it can be restarted and ready for operation by turning the steering wheel. The state of charge of the electrical energy storage device is a parameter representing an absolute indication or a relative indication (for example a percentage share of the total storage capacity defined by a limit value). It is provided that the energy storage device is prevented from being overcharged, for example by a protection circuit associated with the energy storage device.

[0021] In another embodiment, the steering wheel actuator device is configured to, during normal operation, cause electrical energy from an electrical energy source to be at least partially stored in the electrical energy storage device in case the state of charge of said electrical energy storage device is below a limit value. In addition to or as an alternative to charging the electrical energy storage device by the rotational movement of the steering wheel, the internal electrical energy storage device of the steering wheel actuator device is charged by the external electrical energy source if the external electrical energy source is available during normal operation.

[0022] In one embodiment of the steering wheel actuator arrangement, the electrical energy storage device comprises a storage capacitor. Alternatively, the electrical energy storage device may be, for example, a rechargeable battery (eg a lithium-ion battery).

[0023] In one embodiment of the steering wheel actuator device, the adjusting motor device is configured to switch to a phase short-circuit operating state at least during abnormal operation when the state of charge of the energy storage device reaches a limit value. This can occur, for example, when the energy storage device is charged to its maximum level. In the phase short-circuit operating state, the phases of the adjusting motor are short-circuited by a switching module consisting of semiconductor switching elements, so that when the driver moves the steering wheel, the adjusting motor acts as an electromagnetic brake. The steering wheel movement is damped in this way. The energy generated can be dissipated as heat. The semiconductor switching elements of the switching module of the adjusting motor device can be configured for this purpose so that they switch to the phase short-circuit operating state depending on the control signals received from the control device or in the event of a loss of all control signals.

[0024] Since electrical energy is consumed in the phase short-circuit operating state at least for generating control signals and operating the steering wheel angle measuring device, the state of charge of the electrical energy storage device changes slowly and drops below the limit value. The regulating motor device can then be restored to the generator operating state and the electrical energy storage device can be recharged until the limit value is reached again. Thus, overcharging of the energy storage device can be avoided and at the same time discharging of the energy storage device can be prevented, so that the steering function remains available. In a preferred embodiment in which the control device remains ready for operation, the control device is configured to adapt the regulating motor torque generated in the generator operating state to the damping torque last generated in the phase short-circuit operating state after switching back from the phase short-circuit operating state. This provides the advantage that the driver's perception of changes in the operating state is reduced.

[0025] In another embodiment, the semiconductor switching elements of the regulating motor device can also be designed to switch directly to the phase short-circuit operating state in the event of a failure in the electrical energy supply. This is advantageous in particular in alternative embodiments of the steering wheel actuator device in which the regulating motor device is configured to switch to the phase short-circuit operating state during abnormal operation and to generate electrical energy in the event that the applied driver torque exceeds the damping torque generated in the phase short-circuit operating state. In other words, in this embodiment, in the event of a failure in the external electrical energy supply, the switch to the phase short-circuit operating state takes effect directly, wherein it is provided that electrical energy is also generated in this state and used to charge the electrical energy storage device. This eliminates the need to continuously switch the operating state of the regulating motor device in order to prolong the steering operation capability.

[0026] In one embodiment, the steering wheel actuator device further has a disconnection device for interrupting the electrical connection with the electrical energy source at least during abnormal operation. This avoids that the electrical energy storage device discharges through the electrical energy source in the event of a short circuit of the electrical energy source to ground. A disconnection device of this type may, for example, comprise a diode circuit.

[0027] In one embodiment of the steering wheel actuator device, the storage capacity of the electrical energy storage device is defined based on the average duration of inactive phases of the steering wheel. Since the state of charge of the electrical energy storage device depends on the rotational movement of the steering wheel at least during abnormal operation, it may in principle be the case that too little steering movement causes the energy storage device to be charged more slowly than it is discharged to maintain the steering function. Therefore, in the described embodiment, the storage capacity is defined based on the average duration of inactive phases, i.e. time periods without steering movement, so that the probability of the electrical energy storage device being discharged during inactive phases is reduced to a defined acceptably low value.

[0028] According to a second aspect of the invention, a steer-by-wire system for a motor vehicle comprises a steering wheel actuator arrangement according to the first aspect of the invention and an axle actuator arrangement electrically connected to the steering wheel actuator arrangement. According to a third aspect of the invention, a motor vehicle comprises a steer-by-wire system according to the second aspect of the invention.

[0029] Furthermore, according to a fourth aspect of the invention, a method for operating a steering wheel actuator device for a steer-by-wire system for a motor vehicle, wherein the steering wheel actuator device has at least one steering wheel angle measuring device for measuring a steering wheel angle of a steering wheel, a regulating motor device for generating a regulating motor torque for counteracting a driver torque applied to the steering wheel, a control device and an electrical energy storage device chargeable to a limit value, the method comprising the following steps: supplying electrical energy to the steering wheel actuator arrangement at least during normal operation via an electrical energy source connected to the steering wheel actuator arrangement; and During abnormal operation when the electrical energy source does not supply electrical energy to the steering wheel actuator device, at least at least one steering wheel angle measuring device of the steering wheel actuator device is supplied with stored electrical energy by the electrical energy storage device of the steering wheel actuator device.

[0030] In one embodiment, the method further comprises the step of supplying stored electrical energy to the control device of the steering wheel actuator device via the electrical energy storage device of the steering wheel actuator device during abnormal operation when the electrical energy source does not supply electrical energy to the steering wheel actuator device.

[0031] In one embodiment, the method further comprises the following steps: When the driver torque applied in the generator operating state exceeds the regulating motor torque, electric energy is generated by regulating the motor device. In an exemplary embodiment, when the state of charge of the electric energy storage device is below a limit value, it is also provided that the electric energy generated in the generator operating state is at least partially stored in the electric energy storage device. Alternatively or additionally, in another embodiment of the method, when the state of charge of the electric energy storage device is below a limit value, it is provided that during normal operation, electric energy from an electric energy source is at least partially stored in the electric energy storage device.

[0032] In a further embodiment, the method further comprises switching the regulating motor means to the phase short-circuit operating state during abnormal operation when the state of charge of the electrical energy storage device reaches a limit value. In an alternative embodiment, it can also be provided directly during abnormal operation that the regulating motor means is switched to the phase short-circuit operating state and generates electrical energy when the applied driver torque exceeds the damping torque generated in the phase short-circuit operating state.

[0033] Furthermore, in another embodiment, it is provided that the method further comprises interrupting the electrical connection to the source of electrical energy during abnormal operation.

[0034] The advantages and special features of the steering wheel actuator device according to the invention, including embodiments thereof, are therefore also achieved in a steer-by-wire system, a motor vehicle and a method of operating a steering wheel actuator device for a steer-by-wire system of a motor vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other advantages of the present invention can also be seen in the detailed description and the accompanying drawings. The present invention is further explained in detail below in conjunction with the following description of exemplary embodiments with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram showing an example of a motor vehicle having a steer-by-wire system with a steering wheel actuator arrangement according to an embodiment of the present invention; Figure 2 A schematic diagram showing a first example of a steering wheel actuator device for a steer-by-wire system according to another embodiment of the present invention; Figure 3 A schematic diagram showing a second example of a steering wheel actuator device for a steer-by-wire system according to yet another embodiment of the present invention; Figure 4 A schematic diagram showing a third example of a steering wheel actuator device for a steer-by-wire system according to yet another embodiment of the present invention; Figure 5 A schematic diagram showing the operating state of the adjustment motor device during normal operation of the steering wheel actuator device; Figure 6 A schematic diagram showing the operating state of the adjustment motor device during abnormal operation of the steering wheel actuator device; Figure 7 A schematic diagram showing an example of a method of operating a steering wheel actuator device for a steer-by-wire system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0036] Unless otherwise stated, the same or similar reference numbers refer to the same or similar elements in the drawings.

[0037] Obviously other embodiments can be used and structural or logical modifications can be made without departing from the protection scope of the present invention. Unless otherwise specifically indicated, the features of the different exemplary embodiments described above and below can obviously be combined with each other. Therefore, this description should not be interpreted as restrictive, and the protection scope of the present invention is defined by the appended claims.

[0038] Figure 1A schematic diagram of an example of a motor vehicle 100 according to an embodiment of the invention is shown, the motor vehicle 100 having a steer-by-wire system 105 with a steering wheel actuator device 110. The steering wheel actuator device 110 is connected to an axle actuator device 120 via an electrical connection 130. The electrical connection 130 enables the exchange of electrical signals and can be, for example, a direct conductive cable connection. However, an electrical connection is also provided, for example, if both the steering wheel actuator device 110 and the axle actuator device 120 are connected to an onboard power supply system (e.g. a CAN bus) of the motor vehicle 100 via a suitable interface, through which the electrical signals (in particular steering commands or related steering angle information) are transmitted. The steering wheel actuator device 110 is arranged on a steering wheel 140 of the motor vehicle in order to measure the current steering wheel angle on the one hand and to apply a regulating motor torque on the other hand to counteract the driver torque applied by the driver to the steering wheel 140. The steering wheel actuator device 110 is also connected to an electrical energy source 150, which supplies electrical energy to the steering wheel actuator device 110 at least during normal operation. In the illustrated embodiment, the axle actuator device 120 is also connected to a source of electrical energy 150 .

[0039] The axle actuator device 120 is connected to an axle 165 or a steerable steerable wheel 170, 171 of the motor vehicle 100 so that the steering angle of the wheel 170, 171 can be changed by a suitable mechanism (not shown). The axle actuator device 120 is connected to a further electrical energy source 160 in order to be able to operate the axle actuator device 120. In the embodiment shown, the steering wheel actuator device 110 is also connected to a further electrical energy source 150. The motor vehicle 100 also has at least one further axle 175, which is provided with two wheels 180, 181.

[0040] Figure 2 1 is a schematic diagram of a first example of a steering wheel actuator device 210 for a steer-by-wire system according to another embodiment of the present invention. The steering wheel actuator device 210 has a steering wheel angle measuring device 211 for measuring the steering wheel angle of the steering wheel 140, a regulating motor device 212 for generating a regulating motor torque for offsetting the driver torque applied to the steering wheel 140, and a control device 219. Figure 2 In the embodiment, the steering wheel actuator device 210 is connected to an electrical energy source 250. The electrical energy source 250 supplies electrical energy to the steering wheel actuator device 210 during normal operation. The steering wheel actuator device 210 also has an electrical energy storage device 216, which can be charged to a limit value and is configured to provide stored electrical energy to at least the steering wheel angle measuring device 211 in the event of abnormal operation, in which the steering wheel actuator device 210 is no longer supplied with electrical energy by the electrical energy source 250. Figure 2In the embodiment shown, the electrical energy storage device 216 comprises in particular a storage capacitor 217 and a resistor 218. In the embodiment shown, the steering wheel angle measuring device is not integrated into the control device 219, but is itself designed to transmit steering angle information generated based on the measured steering wheel angle to the axle actuator device of the steer-by-wire system via an electrical connection 230, for example an interface to a CAN bus. According to an embodiment, it is therefore no longer necessary to use the energy stored in the electrical energy storage device 216 to activate the control device 219, which can be, for example, an electronic control unit or a different processor, during abnormal operation.

[0041] The regulating motor device 212 has an electric motor (e.g. a brushless DC motor) as the regulating motor 213, and has a first switch module 214 and a second switch module 215 for switching the phases of the regulating motor 213. The switch modules 214, 215 are composed of activatable semiconductor switching elements (e.g. inactivated self-conducting or inactivated self-blocking field effect transistors). The control device 219 is configured to transmit an activation signal to the switch module to control the operating state of the regulating motor device 212. Therefore, in the embodiment shown, it can be provided that during normal operation when the electric energy source 250 is not powered, only the steering wheel angle measuring device 211 is powered by the electric energy storage device 216, while the control device 219 remains closed and the switch modules 214, 215 do not perform activation. The unactivated conductive and blocking semiconductor switching elements are switched so that even without an activation signal from the control device 219, the regulating motor device 212 is switched to a generator operating state that generates a damping torque, wherein in this case, if the applied driver torque exceeds the damping torque generated in the generator operating state, electrical energy is also generated in this state, so that the energy storage device 216 can also be charged in this state based on the rotational movement of the steering wheel.

[0042] Figure 3 FIG. 2 is a schematic diagram showing a second example of a steering wheel actuator device 310 for a steer-by-wire system according to yet another embodiment of the present invention. Figure 2 Like the embodiment shown, the steering wheel actuator device 310 also has a steering wheel angle measuring device 311 for measuring the steering wheel angle of the steering wheel 140, an adjusting motor device 312 for generating an adjusting motor torque for counteracting the driver torque applied to the steering wheel 140, and a control device 319. Figure 3 In the embodiment, the steering wheel actuator device 310 is connected to an electrical energy source 350. The electrical energy source 350 supplies electrical energy to the steering wheel actuator device 310 during normal operation.

[0043] The steering wheel actuator device 310 also has an electrical energy storage device 316 which can be charged to a limit value. Figure 3In the illustrated embodiment, the electrical energy storage device 316 has a storage capacitor 317 and a resistor 318 .

[0044] Figure 3 The electrical energy storage device 316 shown is designed to provide stored electrical energy not only for the steering wheel angle measuring device 311 but also for the control device 319. Since the control device 319 in this embodiment also remains switched on during abnormal operation, i.e. in the event of a power supply failure of the external electrical energy source 350 (i.e. an electrical energy source not associated with the steering wheel actuator device but connected to the steering wheel actuator device), the steering wheel angle measuring device 311 can be simplified and integrated into the control device 319, wherein the communication of the steering angle information generated to the axle actuator device of the steer-by-wire system is also performed by the control device 319 via the electrical connection 330 (e.g. an interface to a CAN bus).

[0045] Figure 3 The illustrated adjustment motor arrangement 312 corresponds largely to Figure 2 The regulating motor device 212 shown has an electric motor (eg a brushless DC motor) as a regulating motor 313, and has a first switching module 314 and a second switching module 315 for switching each phase of the regulating motor 313. The switching modules 314 and 315 are composed of activatable semiconductor switching elements.

[0046] The control device 319 is configured to transmit an activation signal to the switch module to control the operating state of the adjustment motor device 312. Thus, in the embodiment shown, it can be provided that during normal operation, but in particular also during abnormal operation, the control device 319 activates the switch modules 314, 315 so that the adjustment motor device 312 is operated in the generator operating state, that is, if the driver torque applied by the driver to the steering wheel exceeds the adjustment motor torque, electrical energy is generated, wherein the electrical energy is at least partially stored in the electrical energy storage device 316 if the state of charge of the electrical energy storage device 316 is below a limit value corresponding to, for example, the maximum storage capacity. If the state of charge of the electrical energy storage device 316 reaches the limit value during abnormal operation, the adjustment motor device 312 is configured to switch to the phase short-circuit operating state, in which the rotational movement of the steering wheel is damped. Due to the consumption of electrical energy in the phase short-circuit operating state, the state of charge of the electrical energy storage device slowly drops below the limit value again. Then, it can be provided that the generator operating state is restored and the electrical energy storage device 316 is recharged until the limit value is reached again.

[0047] Figure 4 FIG. 4 is a schematic diagram showing a third example of a steering wheel actuator device 410 for a steer-by-wire system according to yet another embodiment of the present invention. The illustrated embodiment corresponds almost completely to FIG. Figure 3The embodiments shown in the drawings, therefore, for a detailed description of the corresponding elements, reference can be made to Figure 3 In addition, the steering wheel actuator device 410 has a disconnect device 420 to interrupt the electrical connection with the electrical energy source 450 during abnormal operation. This prevents the electrical energy storage device 416 from discharging via the electrical energy source 450 in the event that the electrical energy source 450 is short-circuited to ground. Figure 4 The disconnect device 420 is shown by way of example only. Figure 3 An embodiment of a steering wheel actuator device 310, 410 is shown in FIG. Figure 2 The illustrated embodiment of the steering wheel actuator device may also be correspondingly extended to include a disconnect device to interrupt the electrical connection to the electrical energy source during abnormal operation.

[0048] Figure 5 A schematic diagram of possible operating states 500 of the regulating motor arrangement during normal operation of the steering wheel actuator arrangement is shown. Normal operation occurs if the steering wheel actuator arrangement is supplied with electrical energy as intended by an external electrical energy source, i.e. an energy source not associated with the steering wheel actuator arrangement but connected to the steering wheel actuator arrangement, e.g. a vehicle battery.

[0049] In the active torque operating state 501, the control device actively prompts the regulating motor to generate the regulating motor torque T M , the regulating motor torque T M Exactly equal to or greater than the driver torque T applied by the driver to the steering wheel D In this operating state, the regulating motor device consumes electrical energy. This situation may occur, for example, if the steering wheel actuator device simulates a situation for the driver in which one of the steering wheels of the motor vehicle is blocked by contact with a curb and can no longer be aligned as desired.

[0050] In the generator operating state 502 , the driver torque T D Exceeds the regulating motor torque T M In other words, the driver, by appropriately activating the switch module of the regulating motor arrangement via the control device, turns the steering wheel against the torque generated by the regulating motor, which is intended to simulate the current driving conditions or road conditions in the direction desired by the driver. In this state, the regulating motor arrangement generates electrical energy according to the principle of a generator, which is either consumed directly or stored in the electrical energy storage device of the steering wheel actuator arrangement.

[0051] In the phase short-circuit operating state 503, the phases of the regulating motor are short-circuited by the semiconductor switching elements of the switching module of the regulating motor arrangement, so that if the driver moves the steering wheel, the regulating motor acts as an electromagnetic brake. In this way, the steering wheel movement is damped. Even if an electrical energy source is available, it can be provided that this fault state can be actively activated by corresponding switching of the switching module. In this state, the driver torque T D exceeds the damping torque generated by the phase short circuit (i.e. the passively regulated motor torque T M* ).

[0052] Figure 6 A schematic diagram showing an operating state 600 of the adjustment motor arrangement during abnormal operation of the steering wheel actuator arrangement is shown.

[0053] Abnormal operation may occur if the steering wheel actuator device is not supplied with electrical energy by the external electrical energy source as intended, but said electrical energy source fails, is switched off or is defective. In this case, the internal electrical energy storage device is intended to supply electrical energy to the steering wheel actuator device or at least a part of the steering wheel actuator device, in particular at least the steering wheel angle measuring device and possibly the control device.

[0054] During abnormal operation, the active torque operating state of the regulating motor arrangement is not available.

[0055] The generator operating state 602 corresponds to the generator operating state 502 during normal operation of the steering wheel actuator arrangement, wherein the generator operating state 602 provides a facility to charge the internal electrical energy storage device during abnormal operation even if an external electrical energy source is not available.

[0056] The phase short-circuit operating state 603 corresponds to the phase short-circuit operating state 503 during normal operation. According to an embodiment, switching to the phase short-circuit operating state 603 is only performed when the internal electrical energy storage device is fully charged to its limit value, that is, when no further charging is possible in the generator operating state 602. Alternatively, switching to the phase short-circuit operating state 603 can be performed earlier if the regulating motor device is also designed to generate electrical energy in the phase short-circuit operating state 603.

[0057] Figure 7 A schematic diagram of an example of a method 700 for operating a steering wheel actuator device for a steer-by-wire system according to another embodiment of the invention is shown. The method 700 starts in an initial state 701 when the steering wheel actuator device is activated. This occurs in particular when a motor vehicle having a steer-by-wire system associated with the steering wheel actuator device is started. The steering wheel actuator device has at least one steering wheel angle measuring device for measuring a steering wheel angle of the steering wheel, a steering wheel torque generating device for counteracting a driver torque T applied to the steering wheel, and a steering wheel angle measuring device for generating a steering wheel torque generating device for counteracting a driver torque T applied to the steering wheel. DAdjustment motor torque T M A regulating motor device, a control device and an energy storage device that can be charged to a limit value G.

[0058] First a check 702 is performed to determine whether an external electrical energy source is supplying electrical energy to the steering wheel actuator arrangement, wherein this check is performed continuously while the method is being performed.

[0059] If check 702 shows that the steering wheel actuator assembly is not powered by an external electrical energy source ( Figure 7 In the embodiment shown, for safety reasons, the electrical connection to the electrical energy source is then initially interrupted 703 by the disconnection device. In the following steps, during abnormal operation of the steering wheel actuator device, in which the steering wheel actuator device is not powered by the electrical energy source, the stored electrical energy is supplied 704 to at least one steering wheel angle measuring device by the electrical energy storage device of the steering wheel actuator device, and the stored electrical energy is supplied 705 to the control device of the steering wheel actuator device.

[0060] In a further step, a check 706 is then performed to determine whether the state of charge of the electrical energy storage device is below a limit value G. If this is the case ( Figure 7 If the driver torque T applied to the steering wheel by the driver is D Exceed (i.e. exceed) the regulated motor torque T M , the regulating motor device switches to generator operation and generates 707 electrical energy by the regulating motor device, and then the electrical energy generated in the generator operation state is at least partially stored 708 in the electrical energy storage device if the state of charge of the electrical energy storage device is below the limit value G. The method then continues with supplying 704 electrical energy to the steering wheel angle measuring device.

[0061] If the check 706 carried out to determine whether the state of charge of the electrical energy storage device is below the limit value G shows that this is not the case ( Figure 7 ), the regulating motor device will switch 709 to the phase short-circuit operating state during abnormal operation. Then, the method also continues to supply 704 electrical energy to the steering wheel angle measuring device here.

[0062] If the check 702 performed to determine whether the external electrical energy source is supplying power to the steering wheel actuator device shows that this is the case ( Figure 7 If the steering wheel actuator unit is operating normally,

[0063] In this case, the steering wheel actuator device is supplied 710 with electrical energy at least from an electrical energy source connected to the steering wheel actuator device.

[0064] If the driver torque T applied to the steering wheel by the driver is determined D Is it greater than the regulating motor torque T generated by the regulating motor device? M The inspection 711 conducted showed that this was indeed the case ( Figure 7 ), a check 712 is then performed to determine whether the state of charge of the energy storage device is below the limit value G. If this is the case ( Figure 7 If the state of charge of the electrical energy storage device is below the limit value G, electrical energy from the electrical energy source can be further at least partially stored 715 in the electrical energy storage device during normal operation. The method then continues with supplying 710 electrical energy to the steering wheel actuator device from the electrical energy source connected to the steering wheel actuator device.

[0065] If the check 712 carried out to determine whether the state of charge of the electrical energy storage device is below the limit value G shows that this is not the case ( Figure 7 denoted by “-” in the figure), the method continues similarly by supplying 710 electrical energy to the steering wheel actuator device via an electrical energy source connected to the steering wheel actuator device.

[0066] If the driver torque T applied to the steering wheel by the driver is determined D Is it greater than the regulating motor torque T generated by the regulating motor device? M The inspection 711 conducted showed that this was not the case ( Figure 7 ), the regulating motor arrangement is switched 716 to the active torque operating state, and the method continues similarly with the steering wheel actuator arrangement being supplied 710 with electrical energy via an electrical energy source connected to the steering wheel actuator arrangement. The method ends, for example, when the steering wheel actuator arrangement is switched off, in particular when the motor vehicle is stopped.

[0067] In other embodiments of the method the sequence is different. In one embodiment, for example, the generation of electrical energy can also be provided in the phase short-circuit operating state, i.e. during abnormal operation the regulating motor arrangement is switched to the phase short-circuit operating mode and electrical energy is generated if the applied driver torque exceeds the damping torque generated in the phase short-circuit operating state.

[0068] Reference numerals list 100 Motor Vehicles 105 steer-by-wire system 110 Steering wheel actuator device 120 Axle Actuator Device 130 electrical connection 140 Steering Wheel 150Electric Energy 160 Another Electric Energy Source 165 Axle 170 Steering wheel 171 Steering wheel 175 Another axle 180 non-steering wheel 181 Non-steering wheel 210 Steering wheel actuator device 211 Steering wheel angle measuring device 212 Adjustment motor device 213 Adjustment motor 214 first switch module 215 Second switch module 216Electric energy storage device 217 Storage Capacitor 218 resistor 219 Control Device 230 electrical connection 250 Electricity 310 Steering wheel actuator device 311 Steering wheel angle measuring device 312 Adjustment motor device 313 Adjustment motor 314 first switch module 315 Second switch module 316Electric Energy Storage Device 317 Storage Capacitor 318 resistor 319 Control Device 330 electrical connection 350 Electricity 410 Steering wheel actuator device 411 Steering wheel angle measuring device 412 Adjustment motor device 413 Adjustment motor 414 first switch module 415 Second switch module 416Electric Energy Storage Device 417 Storage Capacitor 418 resistor 419 Control Device 420 disconnect device 430 electrical connection 450 Electric Energy 500 Adjusting the operating state of the motor device during normal operation of the steering wheel actuator device 501 Active torque operation state 502 Generator operating status 503 Phase short circuit operation status 600 Adjusting the operating state of the motor device during abnormal operation of the steering wheel actuator device 602 Generator operating status 603 Phase short circuit operation status 700 Method of operating a steering wheel actuator device 701 Initial State 702 Inspection 703 Interrupt 704 Supply 705 Supply 706 Inspection 707 generated 708 Storage 709 Switch 710 Supply 711 Inspection 712 Inspection 713 generated 714 Storage 715 Storage 716 Switch

Claims

1. A steering wheel actuator device (110, 210, 310, 410) for a steer-by-wire system (105) of a motor vehicle (100), comprising: At least one steering wheel angle measuring device (211, 311, 411) for measuring a steering wheel angle of a steering wheel (140); a regulating motor device (212, 312, 412) for generating a regulating motor torque that counteracts a driver torque applied to the steering wheel (140); and Control device (219, 319, 419), wherein The steering wheel actuator device (210, 310, 410) is connectable to an electrical energy source (250, 350, 450), the electrical energy source (250, 350, 450) supplies electrical energy to at least the steering wheel actuator device (210, 310, 410) during normal operation, and is characterized in that the steering wheel actuator device (210, 310, 410) also has an energy storage device (216, 316, 416), the energy storage device (216, 316, 416) can be charged to a limit value and is configured to supply stored electrical energy to at least at least one steering wheel angle measuring device (211, 311, 411) when the electrical energy source (250, 350, 450) does not supply electrical energy to the steering wheel actuator device (210, 310, 410) during abnormal operation.

2. A steering wheel actuator device according to claim 1, wherein the steering wheel actuator device (210, 310, 410) is configured such that during abnormal operation the electrical energy storage device (216, 316, 416) also supplies stored electrical energy to at least the control device (219, 319, 419).

3. A steering wheel actuator arrangement according to claim 1 or 2, wherein the regulating motor arrangement (212, 312, 412) is configured to generate electrical energy in a generator operating state if an applied driver torque exceeds the regulating motor torque.

4. The steering wheel actuator device according to claim 3, wherein the steering wheel actuator device (210, 310, 410) is configured to cause the electrical energy generated in the generator operating state to be at least partially stored in the electrical energy storage device (216, 316, 416) when the state of charge of the electrical energy storage device (216, 316, 416) is below the limit value.

5. A steering wheel actuator device according to one of the preceding claims, wherein the steering wheel actuator device (210, 310, 410) is configured to cause electrical energy from the electrical energy source (250, 350, 450) to be at least partially stored in the electrical energy storage device (216, 316, 416) during normal operation if the state of charge of the electrical energy storage device (216, 316, 416) is below the limit value.

6. Steering wheel actuator arrangement according to one of the preceding claims, wherein the electrical energy storage device (216, 316, 416) comprises a storage capacitor, a battery or an accumulator (217, 317, 417).

7. Steering wheel actuator device according to one of the preceding claims, wherein the adjusting motor device (212, 312, 412) is configured to switch to a phase short-circuit operating state at least during abnormal operation if the state of charge of the electrical energy storage device (316, 416) reaches the limit value.

8. Steering wheel actuator arrangement according to one of claims 1 to 6, wherein the regulating motor arrangement (212, 312, 412) is configured to switch to a generator operating state if an applied driver torque exceeds a damping torque generated in the generator operating state and to generate electrical energy during abnormal operation.

9. Steering wheel actuator device according to one of the preceding claims, wherein the steering wheel actuator device (210, 310, 410) further comprises a disconnect device (420) to interrupt the electrical connection to the electrical energy source (250, 350, 450) at least during abnormal operation.

10. Steering wheel actuator arrangement according to one of the preceding claims, wherein the storage capacity of the electrical energy storage device (216, 316, 416) is defined based on an average duration of inactive phases of the steering wheel (140).

11. A steer-by-wire system (105) for a motor vehicle (100), comprising: A steering wheel actuator device (110) according to any one of claims 1 to 10; as well as An axle actuator device (120) is electrically connected to the steering wheel actuator device (110).

12. A motor vehicle (100) having a steer-by-wire system (105) according to claim 11.

13. A method (700) for operating a steering wheel actuator device for a steer-by-wire system of a motor vehicle, wherein the steering wheel actuator device (210, 310, 410) has at least one steering wheel angle measuring device (211, 311, 411) for measuring a steering wheel angle of a steering wheel (140), a regulating motor device (212, 312, 412) for generating a regulating motor torque for counteracting a driver torque applied to the steering wheel (40), a control device (219, 319, 419) and an electrical energy storage device (216, 316, 416) that can be charged to a limit value, wherein the method (700) comprises: supplying (710) electrical energy to the steering wheel actuator device at least during normal operation via an electrical energy source connected to the steering wheel actuator device; as well as During abnormal operation when the electrical energy source does not supply electrical energy to the steering wheel actuator device, stored electrical energy is supplied (704) to at least one of the steering wheel angle measuring devices of the steering wheel actuator device via the electrical energy storage device of the steering wheel actuator device.

14. The method according to claim 13, further comprising: During abnormal operation when the source of electrical energy does not supply electrical energy to the steering wheel actuator device, the control device of the steering wheel actuator device is also supplied (705) with stored electrical energy by the electrical energy storage device of the steering wheel actuator device.

15. The method according to claim 13 or 14, further comprising: In the event that the driver torque applied in the generator operating state exceeds the regulating motor torque, electrical energy is generated (707) by the regulating motor arrangement.

16. The method according to claim 15, further comprising: In a case where the state of charge of the electrical energy storage device is below the limit value, the electrical energy generated in the generator operation state is at least partially stored (708) in the electrical energy storage device.

17. The method according to any one of claims 13 to 15, further comprising: In case the state of charge of the electrical energy storage device is below the limit value, energy from the source of electrical energy is at least partially stored (715) in the electrical energy storage device during normal operation.

18. The method according to any one of claims 13 to 17, further comprising: In case the state of charge of the electrical energy storage device reaches the limit value, the regulating motor device is switched (709) to a phase short-circuit operating state during abnormal operation.

19. The method according to any one of claims 13 to 17, further comprising: During abnormal operation, the regulating motor arrangement is switched to a generator operating state and generates electrical energy in the event of an applied driver torque exceeding the damping torque generated in the generator operating state.

20. The method according to any one of claims 13 to 19, further comprising: An electrical connection to the electrical energy source is interrupted (703) during abnormal operation.

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