Steering system

Abstract

The present invention relates to a steering system (10) for a vehicle, comprising at least one pair of wheel units (15, 20) that can be actuated and deflected independently of one another, wherein each wheel unit (15, 20) is paired with at least one sensor device (17, 22) for detecting a deviation from a specified deflection of the wheel units (15, 20) relative to one another, and each wheel unit (15, 20) is paired with at least one actuation device (16, 21) in order to actuate the wheel units (15, 20), and at least one control unit (35) that is designed to actuate the actuation devices (16, 21) of the wheel units (15, 20) when the sensor devices (17, 22) detect a specified deviation from a specified deflection of the wheel units (15, 20) relative to one another.

Description

Technical Field

[0001] The present invention relates to a steering system for a vehicle having at least one pair of wheel units that can be independently actuated and deflected, a vehicle having such a steering system, and the use of such a steering system in a vehicle. Background Technology

[0002] Steering systems with wheel units capable of independent actuation and deflection are known in particular from vehicles including so-called steer-by-wire systems. In such a system, the driver's steering command is no longer mechanically transmitted via steering gears physically connected to the wheels to be steered, but is instead acquired electronically. The driver's steering command is converted into electronic control signals by a control unit and then released to the corresponding actuators of the wheels to provide the corresponding deflection of the wheels.

[0003] Corresponding steering systems for vehicles are known from DE 10 2004 001 318 A, DE 102 44 141A1, and DE 10 2016 223 332 A1. These steering systems include at least one pair of wheel units that can be actuated and deflected independently of each other. Each wheel unit has a sensor device for detecting deviations from a specified deflection of the wheel unit. Additionally, each wheel unit is assigned an actuation device for actuating the wheel unit.

[0004] It has now been demonstrated that further improvements to this steer-by-wire system are needed, or alternatives to this steer-by-wire system should be provided.

[0005] Against this backdrop, the object of the present invention is to provide an improved steering system that can be used in addition to known steer-by-wire systems or as an alternative to previously known steer-by-wire systems. This and other objects, which may be mentioned or recognized by those skilled in the art upon reading the following description, are achieved through the subject matter of the independent claims. The dependent claims further form, in a particularly advantageous manner, the central conception of the invention. Summary of the Invention

[0006] The steering system for a vehicle according to the invention comprises: at least one pair of wheel units, the at least one pair of wheel units being independently actuated and deflectable; wherein each wheel unit is paired with at least one sensor device for detecting a deviation of a specified deflection of the wheel unit relative to each other; and wherein at least one, preferably each wheel unit, is paired with at least one actuating device to actuate the wheel unit; and at least one control unit configured to actuate the actuating device of the wheel unit when the sensor device detects a specified deviation of the specified deflection of the wheel unit relative to each other.

[0007] In other words, the present invention proposes, in the case of at least two wheel units of a vehicle, detecting whether the relative position / deflection of the wheel units deviates from a specified relative position / deflection, or whether the deflection exceeds a specified maximum deviation. If a specified / predetermined deviation of the deflection of at least two wheel units relative to each other is determined, the control unit can accordingly cancel the deviation, and the two wheel units can be brought back to their corresponding alignment relative to each other by means of an actuation device. Therefore, the present invention can be used to determine, for example, whether the two front wheel units of a vehicle are still deflected or positioned synchronously relative to each other, or within a specified range, as is expected for proper operation. Additionally, electronic synchronization of at least two wheel units can be provided by the present invention. Thus, the function of a steering shaft is simulated, which allows the wheel units to be mechanically positioned relative to each other, and a virtual steering shaft can be provided. The present invention can be used as additional redundancy for a central control system to increase operational reliability and error tolerance in vehicle control and steering, or as an alternative to a central control system.

[0008] This invention is based on the discovery that omitting mechanical wheel axles and corresponding mechanical steering mechanisms can be problematic in certain situations, such as when the central control unit of a steering-by-wire system malfunctions or when the main steering hardware and / or logic is not operating correctly, resulting in asynchronous wheel unit alignment during operation. This can lead to serious vehicle or wheel unit interference / damage or undesirable, potentially dangerous vehicle driving behavior.

[0009] The term "sensor device" should be understood broadly in this context and includes all electronic, mechanical, and other devices used to determine the alignment of wheel units or the synchronous arrangement / positioning of at least two wheel units. Sensor devices can also be designed to detect the alignment of two or more wheel units. The term "actuator" should also be understood broadly in this context and includes almost all devices that can be used to change the orientation / deflection of wheel units. Finally, the term "control unit" should also be understood broadly in this context and includes all single-part and multi-part control devices suitable for processing data from sensor devices (multiple sensor devices) and delivering corresponding control commands to the actuator, thus providing positional changes for the corresponding wheel units.

[0010] In this context, it should be noted that the invention is not limited to a specified wheel layout or the "synchronization" of specified wheel units. For example, left wheel unit pairs, right wheel unit pairs, front wheel unit pairs and / or rear wheel unit pairs, or other wheel units can be synchronized with each other. The invention also includes operating modes in which a wheel unit can be used as a "master" wheel unit and other wheel units are synchronized with that wheel unit. A pair of wheel drives can also be provided as a "master" pair of wheel drives, and other pairs of wheel drives can be synchronized with this pair of wheel drives. Finally, the invention is not limited to a specified number of wheel units or wheel unit pairs; in particular, the invention includes vehicles having four wheel units, six wheel units, or even three wheel units.

[0011] The control unit can be designed to adjust the alignment and / or speed of one or more wheel units when the wheel units are misaligned relative to each other by a specified deviation, i.e., in the presence of synchronization errors. For example, a potentially faulty wheel unit can switch from master mode to slave mode or free-spinning mode to restore synchronization of the wheel units. Corresponding warning messages can also be sent to the vehicle's electronic control system or issued to the driver.

[0012] The control unit can also be designed to adjust the orientation of a pair of rear wheel units based on the orientation of a pair of front wheel units, for example, to reduce the vehicle's turning radius. The orientation of a pair of rear wheel units can be the same as the orientation of a single front wheel unit. The orientation of a pair of rear wheel units can correspond to the orientation of a pair of front wheel units, for example, to achieve special maneuvers such as lateral or diagonal driving of the vehicle. Furthermore, the driving mode of the wheel units can be adjusted based on road conditions and road grip detected using corresponding sensor devices, for example, to provide better traction.

[0013] Preferably, at least one connecting device is provided between the sensor devices of the two wheel units. This connecting device is designed to provide / transmit tensile or compressive loads to the sensor devices when the wheel units deflect relative to each other beyond a specified deviation. For example, such a connecting device could be a hydraulic pressure cable connector and / or a rigid rod made of a pressure-resistant material such as metal, fiberglass, or aluminum. As long as the wheel units are arranged in parallel or synchronously, the connecting device will not transmit any tensile or compressive loads to the sensor devices or one of the multiple sensor devices. However, if the wheel units are no longer arranged as intended, the connecting device is pressed onto the sensor devices or one of the multiple sensor devices, allowing the corresponding deviation to be detected. In other words, the rigid connecting device is attached to both the left and right wheel units such that when both the left and right wheel units maintain the same orientation, the attachment points of the connecting device to the left and right wheel units remain unchanged. Therefore, if the two wheel units change orientation in parallel, the connecting device will move accordingly, and the attachment points will not be affected. However, if the wheel unit changes its alignment in a non-parallel manner, for example due to a mechanical wheel failure or a steering system failure, the connecting device is pushed or pulled so that the alignment deviation can be detected and the control unit can react accordingly, such as reducing the speed, switching the faulty wheel unit to free-spinning mode or from mode, etc.

[0014] Advantageously, at least two connecting devices are provided between the sensor devices of the two wheel units, wherein the connecting devices are securely anchored on opposite sides in each case and designed on the other opposite side in each case to provide tensile or compressive loads on the respective sensor devices when the wheel units deflect relative to each other beyond a specified deviation. For example, the two wheel units can be connected by two rigid connecting devices, such as rods, connecting both the left and right wheel units, such that one connecting device (rod) is rigidly connected to the left wheel unit and the other connecting device (rod) is rigidly connected to the right wheel unit. In this preferred embodiment, the two sensor devices are preferably disposed on the respective wheel units, each sensor device being rigidly engaged with one connecting device and inductively engaged with the other connecting device.

[0015] Furthermore, it is advantageous to provide at least one flexible connecting device between the sensor units, the flexible connecting device being designed to transmit a measurement variable detectable by the sensor units when the wheel units deflect relative to each other beyond a specified deviation. Such a flexible connecting device can be provided, for example, by a pulled or pushed metal wire, a rubber band whose stress and strain levels are measured, or an inflatable hose that is modulated and generates measurable positive and negative pressures at both ends.

[0016] The sensor device preferably includes sensor elements designed to detect the corresponding deflection of the wheel units and transmit the corresponding deflection to the control unit and / or other sensor devices via wireless and / or wired signal connections. For example, wireless signal connections can be achieved using appropriate radio signal standards. Magnetic field fluctuations, electromagnetic field fluctuations, ultrasonic signals, vibrations transmitted through the vehicle body or chassis, or light pulses used in corresponding visible or invisible ranges can also be used for signal exchange. For example, corresponding signal exchange can be provided using radio communication, infrared light communication, current modulation communication, and / or ultra-wideband communication. For example, information about speed, orientation, and other wheel drive characteristics important for safe and efficient driving due to vehicle dependence can be exchanged between wheel units or control devices to enable the detection of synchronization errors and possible optimization operations between the corresponding wheel units. The purpose is to identify and trigger measures to eliminate or compensate for the detected synchronization errors, to restore the synchronized operation level of the wheel units, or to optimize the coordinated operation of the wheel units.

[0017] It is also advantageous that the steering system is a steer-by-wire system and does not include a central control unit for the wheel units, wherein, preferably, the wheel units are not connected via mechanical steering devices.

[0018] Finally, advantageously, the steering system includes at least a first pair of wheel units and at least a second pair of wheel units, wherein one pair of wheel units is actuated according to the deflection of the wheel units of another pair of wheel units. In this preferred embodiment, the first pair of wheel units can be controlled as the master pair and the second pair of wheel units can be actuated as the slave pair. In this context, various configurations are conceivable in practice.

[0019] Furthermore, the present invention relates to a vehicle comprising at least one steering system as described above. Finally, the present invention relates to the use of the aforementioned steering system in a vehicle. Attached Figure Description

[0020] Other advantages and possible applications of the present invention will become apparent from the following description, exemplary embodiments, and accompanying drawings. In the drawings:

[0021] Figure 1 A schematic diagram of a preferred embodiment of the steering system according to the present invention is shown;

[0022] Figure 2 A schematic diagram showing the parallel alignment of the wheel units in the steering system according to the present invention is shown;

[0023] Figure 3 is two schematic diagrams showing the non-parallel alignment of the wheel units in the steering system according to the present invention; and

[0024] Figure 4A schematic diagram of a second preferred embodiment of the steering system according to the present invention is shown. Detailed Implementation

[0025] Figure 1 A schematic diagram of a first preferred embodiment of a steering system 10 according to the present invention is shown. The steering system 10 includes a first wheel unit 15 and a second wheel unit 20.

[0026] Wheel units 15 and 20 each include actuators 16 and 21, by means of which the orientation of wheel units 15 and 20 can be changed. Furthermore, wheel units 15 and 20 each include sensor devices 17 and 22 for detecting deflection of wheel units 15 and 20 or for detecting misalignment of wheel units 15 and 20 relative to each other. In the preferred embodiment shown, a connecting device 30 is arranged between sensor devices 17 and 22. Finally, the preferred embodiment shown includes a central control unit 35. The control unit 35 processes signals from sensor devices 17 and 22 and controls actuators 16 and 21. Alternatively, the control unit 35 may be designed as several parts and / or integrated into sensor devices 17 and 22 and / or actuators 16 and 21. As already explained, in addition to the control unit 35, a central control unit for the steer-by-wire system may also be provided.

[0027] The connecting device 30 can be designed to provide / transmit tensile or compressive loads to the sensor devices 17 and 22, for example, when the deflection of the wheel units 15 and 20 relative to each other exceeds a specified deviation. For example, such a connecting device 30 can be a hydraulic pressure cable connector and / or a rigid rod made of pressure-resistant materials such as metal, fiberglass, or aluminum.

[0028] As long as wheel units 15 and 20 are arranged in parallel or synchronously (see...) Figure 2 If the connecting device 30 does not transfer any tensile or compressive loads to the sensor units 17, 22 or one of the sensor units, then the connection device 30 will not transfer any tensile or compressive loads to the sensor units 17, 22 or one of the sensor units. However, if the wheel units 15, 20 are no longer arranged as intended (see...), the connection device 30 will not transfer any tensile or compressive loads to the sensor units 17, 22 or one of the sensor units. Figure 3a and Figure 3b If the connecting device 30 is pressed onto the sensor devices 17, 22, or one of the sensor devices, the corresponding deviation can be detected. The rigid connecting device 30 shown is attached to both the left wheel unit 15 and the right wheel unit 20, such that both the left wheel unit 15 and the right wheel unit 20 maintain the same orientation (see...). Figure 2When the wheel units 15 and 20 are aligned, the attachment points of the connecting device 30 to the left wheel unit 15 and the right wheel unit 20 remain unchanged. Therefore, if the alignment of the two wheel units 15 and 20 is changed in a parallel manner, the connecting device 30 moves accordingly and the attachment points are unaffected. However, if the wheel units 15 and 20 change their alignment in a non-parallel manner, for example due to a mechanical wheel malfunction or a steering system malfunction (see...), the connection device 30 will move accordingly and the attachment points will remain unaffected. Figure 3a and Figure 3b If the connecting device 30 is pressed or pulled, the alignment deviation is detected and the control unit 35 can react accordingly. The control unit 35 is preferably designed to adjust the alignment and / or speed of one or more wheel units 15, 20 when the deflection of wheel units 15, 20 relative to each other exceeds a specified deviation, i.e., in the event of a synchronization error caused, for example, by an erroneous control signal from the central control unit of the steer-by-wire system. For example, a potentially faulty wheel unit 15, 20 can be switched from master mode to slave mode or free-turning mode to restore synchronization of wheel units 15, 20. A corresponding warning message can also be sent to the vehicle's electronic control system or issued to the driver.

[0029] Alternatively, the connecting device 30 can also be provided by two rigid rods, each of which is firmly anchored on opposite sides and arranged on the other opposite side to provide tensile or compressive loads on the respective sensor devices 17, 22 when the deflection of wheel units 15, 20 relative to each other exceeds a specified deviation. For example, the rods can be connected to both the left and right wheel units, such that one rod is firmly connected to the left wheel unit and the other is firmly connected to the right wheel unit, wherein the rods are connected at their opposite ends to the respective wheel units that are inductively engaged with the respective sensor devices 17, 22. Alternatively or additionally, the connecting device 30 can be implemented as a flexible connecting device 30, which is designed to transmit a measurement variable that can be detected by the sensor devices 17, 22 when the deflection of wheel units 15, 20 relative to each other exceeds a specified deviation. Such a flexible connecting device 30 can be provided, for example, by a pulled or pushed metal wire, a rubber band for measuring tension and strain levels, or an inflatable hose that is modulated and generates measurable positive and negative pressures at both ends. Furthermore, sensor devices 17 and 22 may include sensor components designed to detect corresponding deflections of wheel units 15 and 20 and transmit the data to control unit 35 and / or other sensor devices 17 and 22 via wireless and / or wired connection devices 30 in the form of signal connectors. For example, wireless signal connectivity can be achieved using appropriate radio signal standards. Magnetic field fluctuations, electromagnetic field fluctuations, ultrasonic signals, vibrations transmitted through the vehicle body or chassis, or light pulses used in corresponding visible or invisible ranges can also be used for signal exchange. For example, corresponding signal exchange can be provided using radio communication, infrared light communication, current modulation communication, and / or ultra-wideband communication.

[0030] Figure 2 The alignment of wheel units 15 and 20 during normal parallel operation is shown, wherein the two wheel units 15 and 20 are aligned synchronously, that is, the two wheel units 15 and 20 have the same angle α relative to the direction of travel. Figure 3a and Figure 3b Two examples of misalignment between two wheel units 15, 20 and each other are shown. In the example shown, the angle β of the left wheel unit 15 is less than (see...). Figure 3a ) or greater than (see Figure 3b Angle α is deflected, and wheel units 15 and 20 are no longer synchronously aligned with each other. In this context, it should be noted that the deviation or synchronization error of wheel units 15 and 20 shown is given only as an example, and many other incorrect alignments may exist. For example, two wheel units 15 and 20 with different angles may also point in the same direction. This asynchronous arrangement of wheel units 15 and 20 can also be detected and addressed by the present invention.

[0031] Figure 4 A schematic diagram of a second preferred embodiment of the steering system 10 according to the present invention is shown. Figure 1 In contrast to the exemplary embodiment shown, this exemplary embodiment includes two pairs of wheel units 15, 20, 15', 20'. In the preferred embodiment shown, the two wheel units 15, 20 form the front wheel unit 40 of the vehicle, and the two wheel units 15', 20' form the rear wheel unit 45 of the vehicle. Each wheel unit 15, 20, 15', 20' includes an actuator 16, 21, 16', 21', by means of which the orientation of the wheel units 15, 20, 15', 20' can be changed. Furthermore, each wheel unit 15, 20, 15', 20' has a sensor device 17, 22, 17', 22' for detecting the deflection of the wheel units 15, 20, 15', 20' or for detecting deviations in alignment of the wheel units 15, 20, 15', 20' relative to each other. In the preferred embodiment shown, a connecting device 30 is arranged between the sensor devices 17, 22. In the illustrated embodiment, the control unit is integrated into one wheel unit or four wheel units 15, 20, 15', 20'. Alternatively, the control unit may be integrated into two or three wheel units 15, 20, 15', 20'. In this regard, it should be noted that the invention is not limited to a specific layout / distribution of the control units (multiple control units). For example, it may be possible to... Figure 4 As clearly seen, in this particularly preferred embodiment, wheel units 15, 20, 15', 20' are connected to each other using corresponding connecting devices 30, 30', 30"', 30"'. In this exemplary embodiment, the control unit can also be designed to adjust the alignment of a pair of rear wheel units 45 according to the alignment of a pair of front wheel units 40, for example, to reduce the turning radius of the vehicle. The orientation of the pair of rear wheel assemblies 45 can be the same as the orientation of the individual front wheel assemblies 15, 20. The orientation of the pair of rear wheel units 45 can correspond to the orientation of the pair of front wheel units 40, for example, to achieve special maneuvers such as lateral or diagonal driving of the vehicle. The driving mode of the wheel units 40, 45 can also be adjusted according to road conditions and / or road grip that can be detected using corresponding sensor devices, for example, to provide better traction. Figure 4 As shown, several redundant (virtual) pairs can also be generated between wheel units 15 and 20, and wheel units 15 and 20 can also be synchronized with more than one other wheel unit 15' and 20" at the same time.

[0032] By means of the illustrated implementation, it can be determined, for example, whether the two front wheel units 40 and / or the rear wheel units 45 are still deflected or positioned synchronously relative to each other, or within a specified range, as should be the case for correct operation. Thus, the function of a steering shaft is simulated, which allows the wheel units to be mechanically positioned relative to each other, and a virtual steering shaft can be provided. This invention can be used as additional redundancy for a central control system to increase operational reliability and error tolerance in vehicle control and steering, or as an alternative to a central control system.

[0033] However, the invention is not limited to the previously preferred exemplary embodiments as long as it includes the subject matter of the appended claims.

[0034] List of reference numerals

[0035] 10. Steering System

[0036] 15 First Round Unit

[0037] 16 Actuating devices

[0038] 17 Sensor Device

[0039] 20 Second Round Unit

[0040] 21 Actuating devices

[0041] 22 Sensor Devices

[0042] 30 Connecting Devices

[0043] 35 Control Unit

[0044] 40 Front wheel unit

[0045] 45 Rear Wheel Unit

Claims

1. A steering system (10) for a vehicle, the steering system comprising: At least one pair of wheel units (15, 20), which are capable of being actuated and deflected independently of each other; Each wheel unit (15, 20) is paired with at least one sensor device (17, 22) for detecting a deviation of a specified deflection of the wheel unit (15, 20) relative to each other; Furthermore, at least one wheel unit (15, 20) is paired with at least one actuating device (16, 21) for actuating the wheel unit (15, 20). At least one control unit (35) is configured to actuate the actuation device (16, 21) of the wheel units (15, 20) when the sensor devices (17, 22) detect a deviation of the wheel units (15, 20) from each other by the specified deflection. At least one connecting device is provided between the sensor devices (17, 22) of the two wheel units (15, 20) to transmit a measurement variable detectable by the sensor devices (17, 22) when the wheel units deflect from each other by more than the specified deviation.

2. The steering system (10) according to claim 1, characterized in that, The at least one connecting device is designed to provide a tensile or compressive load to the sensor device (17, 22) when the wheel units (15, 25) deflect relative to each other beyond a specified deviation.

3. The steering system (10) according to claim 1 or 2, characterized in that, At least two connecting devices (30) are provided between the sensor devices (17, 22) of the two wheel units (15, 20), wherein the connecting devices (30) are firmly anchored on opposite sides and designed on the corresponding other opposite side to provide tensile or compressive loads to the respective sensor devices (17, 22) when the wheel units (15, 20) deflect relative to each other by more than a specified deviation.

4. The steering system (10) according to any one of the preceding claims, characterized in that, The connecting device is a flexible connecting device (30).

5. The steering system (10) according to any one of the preceding claims, characterized in that, The sensor devices (17, 22) include sensor elements designed to detect a corresponding deflection of the wheel units (15, 20) and transmit the corresponding deflection to the control unit (35) and / or other sensor devices via a wireless and / or wired signal connector (30).

6. The steering system (10) according to any one of the preceding claims, characterized in that, The steering system (10) is a steer-by-wire system and does not include a central control unit for the wheel units (15, 20).

7. The steering system (10) according to any one of the preceding claims, characterized in that, The wheel units (15, 20) are not connected via mechanical steering devices.

8. The steering system (10) according to any one of the preceding claims, characterized in that, The steering system (10) includes at least a first pair of wheel units (40) and at least a second pair of wheel units (45), wherein one pair of wheel units (40) is actuated according to the wheel unit deflection of the other pair of wheel units (45).

9. A vehicle comprising at least one steering system (10) according to any one of claims 1 to 8.

10. Use of the steering system (10) for a vehicle according to any one of claims 1 to 8 in a vehicle.

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