Drive unit for wheel actuator of steering-by-wire system of vehicle and method for determining position of control lever of wheel actuator

Abstract

The invention relates to a drive unit (100) for a wheel actuator of a steering-by-wire system (S) of a vehicle (F), comprising:-a motor (10) for providing drive power for a control lever of the wheel actuator; a sensor device (20) for determining a position of the control lever (101), the sensor device (20) having a first sensor unit (21) and at least one second sensor unit (22), the first sensor unit (21) being designed to detect an angle of a rotor shaft (11) of the motor (10), and the second sensor unit (22) being designed to detect an angle of the rotor shaft (11) of the motor (10). The invention relates to a wheel actuator (110) comprising a rotor shaft (11), a sensor device (20) for detecting an angle of an auxiliary shaft (12) arranged in mechanical operative connection with the rotor shaft (11), a transmission device (30) for providing mechanical operative connection between the rotor shaft (11) and the auxiliary shaft (12), and a control device (40) for actuating the sensor device (20) and / or for determining a position of a control lever (101) of the wheel actuator (110), the first sensor unit (21) and the second sensor unit (22) have different measurement principles.

Description

[0001] The invention relates to a drive unit for a wheel actuator of a steer-by-wire system for a vehicle. The invention also relates to a corresponding wheel actuator for a steer-by-wire system for a vehicle. The invention also relates to a corresponding steer-by-wire system for a vehicle and a corresponding vehicle. The invention also relates to a method for determining the position of a control rod of a wheel actuator by means of a corresponding drive unit.

[0002] Future steering systems of the steer-by-wire type do not require a steering intermediate shaft between the steering wheel and the tie rods or control rods, since the mechanical connection to the steering wheel is eliminated. In such systems, the steering feel on the steering wheel is provided by force feedback actuators, which are connected to the steering wheel directly or via a transmission. Since there is no mechanical connection to the steering wheel, the position of the tie rod must be adjusted with high precision and in compliance with the highest safety requirements. For this purpose, it is necessary to be able to clearly determine the position of the tie rod at any point in time.

[0003] In order to be able to determine the position of the tie rod unambiguously and with maximum safety integrity at any time, two sensors can be used. In known mechanical systems, one sensor can be arranged in the power pack and one sensor can be arranged on the steering column, which can provide a reference signal for the position of the tie rod.

[0004] In a steer-by-wire system, there is no longer a steering column. It is technically possible to install a "spindle head" with a sensor in its place, but this is not efficient in terms of simple and economical system design.

[0005] The technical problem to be solved by the present invention is therefore to provide an improved drive unit (so-called Powerpack) for a wheel actuator of a steer-by-wire system of a vehicle, which enables reliable, accurate and safe determination of the position of the steering tie rod. The technical problem to be solved by the present invention is also to provide an improved wheel actuator for a steer-by-wire system of a vehicle. The technical problem to be solved by the present invention is also to provide an improved steer-by-wire system for a vehicle and a corresponding vehicle. The technical problem to be solved by the present invention is also to provide a method for determining the position of a control rod of a wheel actuator by means of a corresponding drive unit, which is improved, in particular with regard to fail-safety.

[0006] The technical problem according to the present invention is solved by: a drive unit for a wheel actuator of a steer-by-wire system for a vehicle having the features of an independent device claim, a wheel actuator for a steer-by-wire system for a vehicle having the features of an independent parallel device claim, a corresponding steer-by-wire system for a vehicle having the features of an independent system claim, a corresponding vehicle having the features of another independent parallel device claim, and a method for determining the position of a control rod of a wheel actuator having the features of an independent method claim.

[0007] The invention provides: a drive unit (so-called Powerpack, for example including a motor and a control device) for a wheel actuator of a steer-by-wire system of a vehicle (part of a steer-by-wire system on a vehicle axle). The drive unit has:

[0008] - a motor for providing driving power to the control rods of the wheel actuators,

[0009] Among them, the control rod can also be called a steering tie rod.

[0010] For example, depending on the design of the wheel actuator, the control lever can have different designs and can, for example, include a rack, a lifting lever, etc.;

[0011] - sensor means for determining the position of the control rod,

[0012] The sensor device comprises a first sensor unit and at least one second sensor unit (two or more second or secondary sensor units are conceivable),

[0013] The first sensor unit is designed to detect the angle of the rotor shaft of the motor.

[0014] and wherein the second sensor unit is designed to detect an angle of an auxiliary shaft which is arranged in mechanical operative connection with the rotor shaft,

[0015] - a transmission device for providing a mechanically effective connection between the rotor shaft and the auxiliary shaft,

[0016] In particular, the operative connection between the rotor shaft and the auxiliary shaft is provided in such a way that the rotation angle of the rotor shaft and the rotation angle of the auxiliary shaft preferably have a certain angular ratio over the stroke of the control rod.

[0017] - and a control device for actuating a sensor device and / or a control rod for determining the position of a wheel actuator,

[0018] The first sensor unit and the second sensor unit have different measuring principles.

[0019] The solution according to the invention provides two sensor units or two sensors in the drive unit or power pack. The sensors are used to accurately determine the position of the control rod at any point in time, wherein the rotor shaft can make multiple rotations over the possible travel or adjustment path of the control rod.

[0020] For example, the two sensor units can be designed according to the vernier principle. The vernier principle can be realized, for example, by two sensor values, which change when the motor rotates, so that the position of the control rod can be clearly determined over the entire stroke by the two sensor values. In this case, the magnet (as the first signal generator) can be fixed in a rotationally fixed manner on the rotor shaft of the motor, and the fan-shaped disk for the inductive sensor (as the second signal generator) can be fixed in a rotationally fixed manner on the auxiliary shaft. The effective connection between the two signal generators, for example in the form of a rotation angle relationship or an angle ratio, can be realized by two mutually meshing spur gears in the transmission frame, which are fixed in a rotationally fixed manner on the rotor shaft and the auxiliary shaft and each carry a signal generator. The spur gear on the auxiliary shaft can have a smaller number of teeth than the spur gear on the rotor shaft, so that a transmission ratio can be provided and the angle of the rotor shaft and the angle of the auxiliary shaft have a clear relationship to each other.

[0021] The spur gear of the transmission can advantageously be mounted with the motor shaft in the motor housing. The sensor (as a signal detector) can advantageously be arranged directly on a printed circuit board of the control device.

[0022] The wheel actuator can be arranged on the control rod or spaced apart from the control rod, for example parallel to the control rod.

[0023] According to the invention, the sensor units have different measuring principles or sensor principles. In this way, safety advantages can be achieved. This makes it possible to avoid simultaneous failure of two sensor units under external influences (e.g., by electromagnetic waves), which would occur in the case of the same sensor principle. In addition, mutual influence of the sensors (e.g., crosstalk of signals) can be avoided.

[0024] The first sensor unit can provide the main function for the motor control and for this purpose have a higher resolution than the second sensor unit.

[0025] The second sensor unit can provide a secondary and / or redundant function for the motor control and, if necessary, have a lower resolution than the first sensor unit. The resolution of the second sensor can be selected so that the motor control can also be carried out based on its signal, but the motor control does not have to meet the highest requirements for acoustics and haptics. The goal of the second sensor unit can be to maintain the functionality / usability of the motor control.

[0026] The advantage of two sensor units can also be that mutual monitoring and / or plausibility checking of the sensor units is possible during normal operation. The monitoring and / or plausibility checking can mainly have the following scope:

[0027] A plausibility check of the angle signals from the first sensor unit to the second sensor unit and vice versa, for example by means of a ratio between the angle signals.

[0028] A plausibility check of the control lever position calculated according to the vernier principle with respect to other signals present in the vehicle from which the steering angle can be calculated (eg yaw rate, individual wheel speeds, external sensors, etc.).

[0029] If the sensor is of multi-channel design, the plausibility check can also take into account the respective individual channels of the sensor separately.

[0030] If the primary sensor fails, the secondary sensor can take over the position determination of the control column.

[0031] If the second sensor has a lower resolution or signal quality than the first sensor, it may be advantageous to adjust the control characteristic of the motor control. This can be achieved in various ways:

[0032] - Reduce the dynamics of the superordinate control loop (rack position control);

[0033] - Connecting an attenuation component to the signal (e.g. a low-pass filter);

[0034] - Limit the gradient and amplitude of the signal (target rack position)

[0035] - Switching to another controller parameterization which is adapted for operation via this sensor.

[0036] For a high-precision calculation of the rack position, it may be advantageous if the control rod position from both sensors is present at system startup. After a subsequent partial failure of the sensor, further calculations of the control rod position can also be performed solely from this signal. For example, the count of shaft revolutions can additionally be included in the further calculations.

[0037] The angle calculation based on the offset value starting from the start-up can advantageously be run in the background in the normal case, so that this value is always available in normal operation and can also be checked for plausibility with respect to other available signals according to the above-described method.

[0038] Furthermore, it can be advantageous if one or more of the calculated angles or position information, including associated signals about the status of the plausibility check, are transmitted to one or more vehicle bus systems in order to be used by other control devices in the vehicle.

[0039] Furthermore, it can be provided that the first sensor unit has a first signal transmitter and a first sensor, the first signal transmitter being connected to the rotor shaft in a rotationally fixed manner, the first sensor being arranged, in particular when viewed axially, at the end face in front of the rotor shaft and opposite the first signal transmitter. Furthermore, it can be provided that the second sensor unit has a second signal transmitter and a second sensor, the second signal transmitter being connected to the auxiliary shaft in a rotationally fixed manner, the second sensor being arranged, in particular when viewed axially, at the end face in front of the auxiliary shaft and opposite the second signal transmitter. It can thus be achieved that the sensor unit can use the vernier principle in order to be able to determine the exact position of the control rod over its entire control path at any point in time.

[0040] The first sensor and / or the second sensor can advantageously be arranged on the control device. In this way, the connection of the sensors can be simplified and integration into the power pack can be achieved.

[0041] Furthermore, it may be advantageous if the first sensor unit has a higher resolution and / or signal quality than the second sensor unit. In this way, the first sensor unit can provide a major function in the motor control.

[0042] Furthermore, it is conceivable that the first sensor unit and the second sensor unit can each include at least one of the following sensors:

[0043] - Inductive sensors,

[0044] - Magnetoresistive sensor,

[0045] - Hall sensor,

[0046] -Rotation angle sensor, etc.

[0047] Therefore, already established sensors can advantageously be used for angle determination.

[0048] Furthermore, it is conceivable that the first sensor unit and the second sensor unit can each have at least one of the following measuring principles:

[0049] -Electromechanical,

[0050] -magnetic,

[0051] -induction,

[0052] -Optics, etc.

[0053] Thus, established measuring principles can advantageously be used for angle determination.

[0054] Furthermore, it can be provided that the transmission has a main transmission element, in particular in the form of a gear, preferably in the form of a spur gear, which is connected to the rotor shaft in a rotationally fixed manner and to which the first signal transmitter is fixed. Furthermore, it can be provided that the transmission has at least one auxiliary transmission element, in particular in the form of a gear, preferably in the form of a spur gear, which is connected to the auxiliary shaft in a rotationally fixed manner and to which the second signal transmitter is fixed. In this way, a defined transmission ratio can be provided between the gears. The transmission ratio between the gears can be advantageous in order to achieve an effective connection between the rotor shaft and the auxiliary shaft, so that in particular the rotation angles of the rotor shaft and the auxiliary shaft have a defined ratio over the stroke of the control rod. Thus, an accurate position determination of the control rod can be achieved according to the vernier principle.

[0055] Advantageously, the control device can have a first control unit and a second control unit. This makes it possible to achieve fail-safe operation when operating the sensor.

[0056] Furthermore, it can be advantageous if the first sensor unit has at least one channel to the first control unit and at least one channel to the second control unit. Furthermore, it can be advantageous if the second sensor unit has at least one channel to the first control unit and, if applicable, a channel to the second control unit. In this way, a fail-safety of the channels can be achieved, thereby further increasing the fail-safety of the angle determination.

[0057] The invention further provides a wheel actuator for a steer-by-wire system of a vehicle, comprising a control lever for implementing a steering request and a drive unit for providing the control lever with drive power in order to implement the steering request, wherein the drive unit can be designed as described above. The wheel actuator according to the invention can achieve the same advantages as with the drive unit. These advantages are fully cited here.

[0058] The invention further provides a steer-by-wire system for a vehicle having a corresponding wheel actuator. The steer-by-wire system according to the invention can achieve the same advantages as the drive unit described above. These advantages are fully cited here.

[0059] The invention further provides: a vehicle, in particular a highly automated and / or autonomously driven vehicle, which optionally does not have or does not need to have a steering wheel, with a corresponding steer-by-wire system. The same advantages can be achieved with the vehicle according to the invention as with the drive unit. These advantages are fully cited here.

[0060] The invention further provides a method for determining the position of a control rod of a wheel actuator by means of a drive unit, wherein the drive unit can be designed as described above. The method has the following actions / method steps:

[0061] - using a first sensor unit in order to detect the angle of the rotor shaft of the motor,

[0062] - using a second sensor unit in order to detect the angle of the auxiliary axis,

[0063] The position of a control rod of a wheel actuator is determined with the aid of measured values ​​of the first sensor unit and / or with the aid of measured values ​​of the second sensor unit.

[0064] The same advantages as those achieved with the drive unit can be achieved with the method according to the invention. These advantages are fully cited here.

[0065] Advantageously, the measured values ​​of the first sensor unit can be used for plausibility checking of the measured values ​​of the second sensor unit.

[0066] In order to be able to carry out an advantageous position determination of the control lever with greater accuracy, the available measured values ​​of the first sensor unit and / or the available measured values ​​of the second sensor unit can be combined.

[0067] Advantageously, when the vehicle is started, an offset between the measured values ​​of the first sensor unit and the measured values ​​of the second sensor unit can be determined (for example in the form of an angle ratio) so that if one of the sensor units fails, the position of the control lever can continue to be determined using only one sensor unit. For this purpose, available measured values ​​can be used, which can be supported, for example, by a rotation count, in order to determine the position of the control lever.

[0068] It is particularly advantageous if the determination of the position of the control lever by means of an offset between the measured values ​​of the first sensor unit and the measured values ​​of the second sensor unit can be carried out in parallel with the main (or primary) determination of the position of the control lever (e.g. by means of two measured values, e.g. according to the vernier principle) so that in the event of a failure of one of the sensor units a determination of the control lever position can be provided particularly immediately by means of only one sensor unit.

[0069] Furthermore, it can be advantageous if the control method for controlling the motor fails, wherein in particular at least one of the following measures is carried out if the first sensor unit fails:

[0070] - reducing the dynamics for the superordinate control, in particular the control of the position of the control lever,

[0071] - connecting an attenuation element, for example a low-pass filter, to the signal of the second sensor unit,

[0072] - limiting the gradient and / or amplitude of the signal for the target position of the control rod,

[0073] - Adjusting a control parameter for adjusting the motor and / or for adjusting the position of the control rod.

[0074] In this way, despite a failure of one of the sensor units, an improved regulation of the motor and / or an improved regulation of the position of the control lever can be provided.

[0075] Further advantages, features and details of the invention are apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the accompanying drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. In the drawings:

[0076] Figure 1 An example diagram showing a vehicle having a steer-by-wire system;

[0077] Figure 2 shows an end view of a motor of a drive unit for a wheel actuator;

[0078] Figure 3 An example diagram showing a sensor arrangement for a drive unit of a wheel actuator; and

[0079] Figure 4 The diagram shows an example of a sensor arrangement for a drive unit of a wheel actuator.

[0080] Figures 1 to 4 Used to explain the inventive concept. Figure 1 An exemplary steering system of the steer-by-wire design type or simply steer-by-wire system S is shown for a vehicle F. This steer-by-wire system S does not require a steering intermediate shaft between the steering wheel L and the steering tie rod or control rod 101, because the mechanical connection to the steering wheel L is eliminated. In this steer-by-wire system S, the steering feel on the steering wheel L can be provided by a force feedback actuator 120, which is connected to the steering wheel L directly or via a transmission. Since there is no mechanical connection to the steering wheel L, the position of the steering tie rod must be adjusted with high precision and in consideration of the highest safety requirements.

[0081] In order to be able to clearly determine the position of the steering tie rod or control rod 101 at any time, the invention proposes (see Figures 2 to 4 ): A drive unit 100 (so-called power pack, for example comprising a motor and a control device) for a wheel actuator 110 of a steer-by-wire system S of a vehicle F. The drive unit 100 has:

[0082] a motor 10 for providing driving power to a control rod 101 of a wheel actuator 110,

[0083] Depending on the design of the wheel actuator 110 , in particular the control lever 101 can have different designs and can, for example, include a rack, a lifting lever, etc., wherein: Figure 1Only the wheel actuator 110 is shown, for example, on the control lever 101, wherein as a Figure 1 Alternatively, the wheel actuator 110 may be arranged to be spaced apart from the control rod 101, wherein preferably, the wheel actuator 110 may be connected to the control rod 101 via a transmission device;

[0084] a sensor device 20 for determining the position of the control rod 101 , wherein the sensor device 20 has a first sensor unit 21 and at least one second sensor unit 22 (one or more second or secondary sensor units are conceivable),

[0085] The first sensor unit 21 is designed to detect the angle of the rotor shaft 11 of the motor 10.

[0086] and wherein the second sensor unit 22 is designed to detect the angle of the auxiliary shaft 12, which is arranged in mechanical operative connection with the rotor shaft 11,

[0087] a transmission device 30 for providing a mechanically effective connection between the rotor shaft 11 and the auxiliary shaft 12,

[0088] In particular, the effective connection between the rotor shaft 11 and the auxiliary shaft 12 is provided in such a way that the rotation angle of the rotor shaft 11 and the rotation angle of the auxiliary shaft 12 preferably have a certain angular ratio over the stroke of the control rod 101.

[0089] and a control device 40 for controlling the sensor device 20 and / or for determining the position of the control rod 101 of the wheel actuator 100,

[0090] The first sensor unit 21 and the second sensor unit 22 have different measuring principles.

[0091] like Figure 3 and Figure 4 As shown, two sensor units 21, 22 are provided in the sensor device 20. The two sensor units 21, 22 can respectively have two sensors S1, S2. The sensor units 21, 22 can advantageously be installed in the drive unit 100, in particular in a housing (not shown) of the drive unit 100. The sensors S1, S2 are used to accurately determine the position of the control rod 101 at any time, wherein the rotor shaft 11 can perform multiple rotations on the possible travel or adjustment path of the control rod 101.

[0092] The two sensor units 21, 22 can advantageously be designed according to the vernier principle. The vernier principle can be realized, for example, by two sensor values, which change when the motor 10 rotates, so that the position of the control rod 101 can be clearly determined over the entire stroke by the two sensor values. In this case, for example, a magnet (as a first signal transmitter M1) can be fixed in a rotationally fixed manner on the rotor shaft 11 of the motor 10, and for example, a sector disk for an inductive sensor (as a second signal transmitter M2) can be fixed in a rotationally fixed manner on the auxiliary shaft 12. The effective connection between the two signal transmitters M1, M2, for example in the form of a rotation angle relationship or an angle ratio, can be realized by two mutually meshing transmission elements 31, 32, for example in the form of spur gears, within the scope of the transmission 30, which are respectively fixed in a rotationally fixed manner on the rotor shaft 11 and the auxiliary shaft 12 and carry one signal transmitter M1, M2 respectively. The spur gear on the auxiliary shaft 12 can, for example, have a smaller number of teeth than the spur gear on the rotor shaft 11 , so that a transmission ratio can be provided and the angles of the rotor shaft 11 and the auxiliary shaft 12 have a clear relationship or ratio to one another.

[0093] The transmission elements 31, 32 of the transmission device 30 can be advantageously mounted with the rotor shaft 11 in a housing (not shown) of the drive unit 100. The sensors S1, S2 (as signal detectors) can advantageously be arranged directly on a circuit board of the control device 40.

[0094] According to the invention, the sensor units 21 , 22 have different measuring principles or sensor principles:

[0095] - Electromechanical,

[0096] -magnetic,

[0097] -induction,

[0098] -Optics, etc.

[0099] The sensor units 21 and 22 may respectively have the following different sensors S1 and S2:

[0100] - an inductive sensor (for example for the first sensor S1 ),

[0101] - a magnetoresistive sensor (for example for the second sensor S2),

[0102] - Hall sensor,

[0103] -Rotation angle sensor, etc.

[0104] Different measuring principles can achieve safety advantages, thus avoiding simultaneous failure of both sensor units 21, 22 under external influences (e.g., by electromagnetic waves), which could occur with the same sensor principle. In addition, mutual influences of sensors S1, S2 (e.g., crosstalk of signals) can be avoided.

[0105] The first sensor unit 21 can provide the main function for the motor control and for this purpose have a higher resolution than the second sensor unit 22 .

[0106] The second sensor unit 22 can provide a secondary and / or redundant function for the motor control and, if necessary, have a lower resolution than the first sensor unit 21. The resolution of the second sensor S2 can be selected so that the motor control can also be carried out based on its signal. In the latter case, the motor control does not need to meet the highest requirements for acoustics and haptics. The goal of the second sensor unit 22 can be to maintain the functionality / usability of the motor control.

[0107] The two sensor units 21 , 22 may also have the advantage that mutual monitoring and / or plausibility checking of the sensor units 21 , 22 is possible during normal operation of the wheel actuator 110 , for example:

[0108] A plausibility check of the angle signals from the first sensor unit 21 to the second sensor unit 22 and vice versa from the second sensor unit to the first sensor unit, for example by means of a ratio between the angle signals.

[0109] A plausibility check of the control lever position calculated according to the vernier principle with respect to other signals present in the vehicle F from which the steering angle can be calculated (eg yaw rate, individual wheel speeds, external sensors, etc.).

[0110] - If the sensors S1, S2 are designed as multi-channel (see Figure 3 ), the plausibility check can also take into account the corresponding individual channels K11 , K12 , K21 , K22 of the sensors S1 , S2 separately.

[0111] If the primary sensor S1 fails, the secondary sensor S2 can take over the position determination of the control rod 101 .

[0112] If the second sensor S2 has a lower resolution or signal quality than the first sensor S1, it may be advantageous to adjust the control characteristic of the motor control. This can be achieved in a variety of ways:

[0113] - Reduce the dynamics of the superordinate control loop (rack position control);

[0114] - Connecting an attenuation component to the signal (e.g. a low-pass filter);

[0115] - Limit the gradient and amplitude of the signal (target rack position)

[0116] - Switching to another controller parameterization which is adapted for operation via this sensor.

[0117] For a high-precision calculation of the rack position it is advantageous if the control rod 101 position originating from both sensor units 21 , 22 is present at the start of the system.

[0118] The further calculation of the position of the control rod 101 can also be carried out solely via this signal after a possible subsequent partial failure in one of the sensor units 21, 22. For example, the counting of shaft revolutions can additionally be included in the further calculation.

[0119] The angle calculation based on the offset value starting from the start-up can advantageously be run in the background in the normal case, so that this value is always available in normal operation and can also be checked for plausibility with respect to other available signals according to the above-described method.

[0120] Furthermore, it may be advantageous if one or more of the calculated angles or position information, including associated signals about the status of the plausibility check, are sent to one or more vehicle bus systems in order to be used by other control devices in vehicle F.

[0121] like Figures 2 to 4 As shown, the first sensor unit 21 can have a first signal transmitter M1 and a first sensor S1, the first signal transmitter is connected to the rotor shaft 11 in a rotationally fixed manner, the first sensor S1 is arranged in front of the rotor shaft 11 at the end side, especially when viewed in the axial direction, and is opposite to the first signal transmitter M1. In addition, the second sensor unit 22 can have a second signal transmitter M2 and a second sensor S2, the second signal transmitter is connected to the auxiliary shaft 12 in a rotationally fixed manner, the second sensor is arranged in front of the auxiliary shaft 12 at the end side, especially when viewed in the axial direction, and is opposite to the second signal transmitter M2.

[0122] like Figure 3 and Figure 4 As shown, the first sensor S1 and / or the second sensor S2 may be arranged on the control device 40 , in particular directly on a control circuit board.

[0123] like Figure 2As shown, the transmission 30 can have a main transmission element 31, in particular in the form of a gear, preferably in the form of a spur gear, which is connected to the rotor shaft 11 in a rotationally fixed manner and to which the first signal transmitter M1 is fixed. In addition, the transmission 30 can have at least one auxiliary transmission element 32, in particular in the form of a gear, preferably in the form of a spur gear, which is connected to the auxiliary shaft 12 in a rotationally fixed manner and to which the second signal transmitter M2 is fixed.

[0124] like Figure 3 and Figure 4 As shown, the control device 40 may have a first control unit 41 and a second control unit 42. In addition, the first sensor unit 21 may have at least one channel K11 leading to the first control unit 41 and at least one channel K12 leading to the second control unit 42. In addition, the second sensor unit 22 may have at least one channel K21 leading to the first control unit 41 (see Figure 3 and Figure 4 ) and, if necessary, a channel K22 to a second control unit 42 (see Figure 3 ).

[0125] exist Figure 3 4 shows a possible connection of sensors S1, S2 with a two-channel and / or two-part control device 40. This has the advantage that both sensors S1, S2 are still available when the control unit 41 or 42 is switched off. If in this case there is still a fault in one of the sensors S1, S2, the remaining sensor S1 or S2 can continue to operate in conjunction with the remaining control unit 41 or 42. For example, if channels K11, K12, K21, K22 provide ASIL B relative angle signals, the control unit 41 and / or 42 can determine two ASIL D relative angles from the corresponding two ASIL B relative angle signals. Then the ASIL-D absolute angle can be determined from the two ASIL D relative angles.

[0126] In one embodiment, the task of the second sensor 2 is to maintain the availability of the position signal together with the first sensor S1. The second sensor can be designed as a single channel only (see Figure 4 ). In this case, the following can be done in normal operation: Figure 3The position calculation of the embodiment is possible because all signals on the first control unit 41 are available. This situation does not change if a failure or shutdown of the second control unit 42 due to a fault occurs. If the first control unit 41 is shut down, the system can ensure operation even with limited availability due to the still available angle information from the first sensor S1. That is to say, measures such as driver warnings and / or stopping operation after a certain operating duration or mileage may be required. If these solutions can be implemented within the scope of the safety requirements to be achieved, this embodiment is a simpler and therefore cost-reduced variant of the system. This embodiment takes into account the characteristics of the high-precision calculation of the control lever position from the two sensors S1, S2 when the system is started. It is also possible to perform further calculations based on the knowledge of the position at startup using only the signal of the first sensor S1. The count of sensor rotations can be additionally included in the determination.

[0127] The advantages and special features within the scope of the present disclosure may be particularly manifested as follows:

[0128] Different measuring principles. In the event of external disturbances, for example disturbances caused by a magnetic field, the probability that both sensor units 21 , 22 are disturbed at the same time is low.

[0129] - Arrange the fixed sensor part (sensors S1, S2) before the rotating part (signal generators M1, M2) (see Figure 3 and Figure 4 ).

[0130] - Redundant structure of the sensor units 21 , 22 .

[0131] - Redundant structure of the control units 41 , 42 .

[0132] A plausibility check of the sensor values ​​of the sensor units 21 , 22 .

[0133] Furthermore, it is conceivable that sensor device 20 may also include more than two sensor units 21 , 22 , which may be switched differently or identically relative to one another in order to increase the accuracy and / or robustness of the angle measurement / position determination.

[0134] The above description of the embodiments only illustrates the present invention within the scope of examples. Of course, as long as it is technically meaningful, the individual features of the embodiments can be combined with each other as desired without departing from the scope of the present invention.

[0135] List of reference numerals:

[0136] FTransportation

[0137] S-Wire Steer System

[0138] L Steering wheel

[0139] 120 force feedback actuator

[0140] 110 Wheel Actuator

[0141] 101 Joystick

[0142] 100 drive units

[0143] 10 Motor

[0144] 11 Rotor shaft

[0145] 12 Auxiliary axes

[0146] 20 sensor devices

[0147] 21 sensor units

[0148] 22 sensor units

[0149] M1 Signal Generator

[0150] M2 Signal Generator

[0151] S1 Sensor

[0152] S2 Sensor

[0153] 30 Transmission

[0154] 31 Main transmission components

[0155] 32 Auxiliary transmission elements

[0156] 40 Control device

[0157] 41Control Unit

[0158] 42Control Unit

[0159] K11 Channel

[0160] K12 Channel

[0161] K21 Channel

[0162] K22 channel

Claims

1. A drive unit (100) for a wheel actuator (110) of a steer-by-wire system (S) for a vehicle (F), comprising: - a motor (10) for providing driving power to a control rod (101) of a wheel actuator (110); - a sensor device (20) for determining the position of the control rod (101), in, The sensor device (20) comprises a first sensor unit (21) and at least one second sensor unit (22). The first sensor unit (21) is designed to detect the angle of the rotor shaft (11) of the motor (10). and wherein the second sensor unit (22) is designed to detect an angle of an auxiliary shaft (12) which is arranged in mechanical operative connection with the rotor shaft (11), - a transmission device (30) for providing a mechanically effective connection between the rotor shaft (11) and the auxiliary shaft (12), and a control device (40) for controlling the sensor device (20) and / or for determining the position of a control rod (101) of a wheel actuator (110), wherein the first sensor unit (21) and the second sensor unit (22) have different measuring principles.

2. The drive unit (100) according to claim 1, in, The first sensor unit (21) comprises a first signal transmitter (M1) which is connected to the rotor shaft (11) in a rotationally fixed manner and a first sensor (S1), the first sensor (S1) being arranged, in particular when viewed axially, at the end face in front of the rotor shaft (11) and opposite the first signal transmitter (M1). and / or wherein the second sensor unit (22) comprises a second signal transmitter (M2) and a second sensor (S2), the second signal transmitter being connected to the auxiliary shaft (12) in a rotationally fixed manner, the second sensor being arranged, in particular when viewed axially, at the end face in front of the auxiliary shaft (12) and opposite the second signal transmitter (M2), And / or wherein the first sensor (S1) and / or the second sensor (S2) are arranged on the control device (40).

3. The drive unit (100) according to claim 1 or 2, in, The first sensor unit (21) has a higher resolution and / or signal quality than the second sensor unit (22), And / or wherein the first sensor unit (21) and the second sensor unit (22) can each have at least one of the following sensors: - Inductive sensors, - Magnetoresistive sensor, - Hall sensor, -Rotation angle sensor, etc., And / or wherein the first sensor unit (21) and the second sensor unit (22) can each have at least one of the following measurement principles: - Electromechanical, -magnetic, -induction, -Optics, etc.

4. The drive unit (100) according to claim 1, in, The transmission device (30) has a main transmission element (31), in particular a main transmission element in the form of a gear, which is connected to the rotor shaft (11) in a rotationally fixed manner and to which the first signal transmitter (M1) is fastened. And / or wherein the transmission device (30) has at least one auxiliary transmission element (32), in particular an auxiliary transmission element in the form of a gear, which is connected to the auxiliary shaft (12) in a rotationally fixed manner and to which the second signal transmitter (M2) is fixed.

5. The drive unit (100) according to claim 1, in, The control device (40) comprises a first control unit (41) and a second control unit (42). and / or wherein the first sensor unit (21) has at least one channel (K11) leading to the first control unit (41) and at least one channel (K12) leading to the second control unit (42), And / or wherein the second sensor unit (22) has at least one channel (K21) leading to the first control unit (41) and, if necessary, a channel (K22) leading to the second control unit (42).

6. A wheel actuator (110) for a steer-by-wire system (S) of a vehicle (F), comprising a control rod (101) for implementing a steering request and a drive unit (100) according to one of the above claims for providing drive power to the control rod (101) to implement the steering request.

7. A steer-by-wire system (S) for a vehicle (F) having a wheel actuator (110) according to the preceding claim.

8. A vehicle (F), in particular a highly automated and / or autonomously driven vehicle, having a steer-by-wire system (S) according to the preceding claim.

9. A method for determining the position of a control rod (101) of a wheel actuator (110) by means of a drive unit (100) according to one of the preceding claims, comprising: Using a first sensor unit (21) to detect the angle of a rotor shaft (11) of a motor (10), - using a second sensor unit (22) in order to detect the angle of the auxiliary shaft (12), - determining the position of a control rod (101) of a wheel actuator (110) with the aid of measured values ​​of the first sensor unit (21) and / or with the aid of measured values ​​of the second sensor unit (22).

10. The method according to the preceding claim, in, The measured values ​​of the first sensor unit (21) are used for plausibility checking of the measured values ​​of the second sensor unit (22).

11. The method according to any one of the preceding claims, in, combining the available measured values ​​of the first sensor unit (21) and / or the available measured values ​​of the second sensor unit (22) in order to determine the position of a control rod (101) of a wheel actuator (110), and / or wherein, when the vehicle (F) is started, an offset between a measured value of the first sensor unit (21) and a measured value of the second sensor unit (22) is determined so that, in the event of failure of one of the sensor units (21, 22), the position of the control lever (101) can continue to be determined by only one sensor unit (21, 22), And / or wherein the determination of the position of the control rod (101) by means of an offset between a measurement value of the first sensor unit (21) and a measurement value of the second sensor unit (22) is performed in parallel with a main determination of the position of the control rod (101), so that in the event of a failure of one of the sensor units (21, 22) a determination of the position of the control rod (101) can be provided by only one sensor unit (21, 22).

12. The method according to any one of the preceding claims, in, In the event of a failure of the first sensor unit (21) and / or the second sensor unit (22), a control method for regulating the motor (10) is adjusted. In particular, when the first sensor unit (21) fails, at least one of the following measures is performed: - reducing the dynamics for the superordinate control, in particular the control of the position of the control lever (101), - connecting an attenuation element, such as a low-pass filter, to the signal of the second sensor unit (22), - limiting the gradient and / or amplitude of the signal for the target position of the control rod (101), - Adjusting a control parameter for adjusting the motor (10) and / or for adjusting the position of the control rod (101).

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