Method for operating motor vehicle and motor vehicle having steering unit

Abstract

The invention relates to a method for operating a motor vehicle (10) having a steering unit (12) which is designed to specify a steering angle of a wheel pair (14) on the basis of a steering signal and to provide an angle signal which characterizes an actual steering angle of the wheel pair (14), said steering unit (12) being designed to specify the steering angle of the wheel pair (14) in the event of absence of reception of the angle signal at a control unit (16) designed to provide the steering signal. According to the invention, the actual steering angle is estimated on the basis of at least one sensor signal which is provided by the sensor unit (18) and characterizes the movement of the motor vehicle (10), and the at least one actuator unit (20) is set on the basis of the estimation in such a way that a target trajectory (22) which is specified on the basis of the steering signal is specified and / or a safe operation of the motor vehicle (10) is / are specified. The invention further relates to a motor vehicle (10).

Description

Technical Field

[0001] This invention relates to a method for operating a motor vehicle with a steering unit according to claim 1. Furthermore, this invention relates to a motor vehicle with a steering unit according to claim 10. Background Technology

[0002] Motor vehicles (such as passenger cars) have a steering unit that guides and thus controls the vehicle. The steering unit is typically designed such that by manipulating gears to move a rack, the steering angle of the wheels, especially the wheels on the front axle of the vehicle, can be adjusted.

[0003] Nowadays, it's possible that the steering wheel will no longer be mechanically connected to gears, for example, to preset the steering angle. Thus, the servo mechanism of the steering unit can be controlled solely by electrical signals, preset by, for example, the steering wheel and / or a driver assistance system. To obtain feedback on the steering position, a sensor is typically provided, which feeds back the steering angle position to, for example, the driver assistance system. The servo mechanism of the steering unit, for example, forms a steering actuator, which, in the case of a rack, can output a rack position signal, or a sensor unit can be provided to output this signal. It can be configured such that, for example, the sensor fails and the signal is not returned.

[0004] DE 10 2017 223 295 A1 discloses a method for operating a motor vehicle, which, after the initial accident of the motor vehicle (in which the braking and / or steering function of the front wheels of the motor vehicle may be limited and / or the motor vehicle is involved in a collision), should be used to prevent subsequent accidents of the motor vehicle by manipulating the rear wheel steering mechanism. Summary of the Invention

[0005] The objective of this invention is to provide a method for operating a motor vehicle and a motor vehicle in which the method and the motor vehicle can compensate for the failure or absence of the angle signal of the steering unit at the control unit, so as to advantageously guide the motor vehicle or make it move in safe operation.

[0006] According to the invention, this task is solved by the subject matter of the independent claims. Advantageous embodiments and improvements of the invention are given in the dependent claims, as well as in the description and drawings.

[0007] A first aspect of the invention relates to a method for operating a motor vehicle having a steering unit configured to preset the steering angle of a wheel pair, particularly a wheel pair mounted on the front axle, based on or according to a steering signal, and to provide, for example, an angle signal characterizing the actual steering angle of the wheel pair via a sensor device.

[0008] In order to enable the advantageous operation of motor vehicles, especially those configured as passenger cars or freight vehicles, in the method according to the invention, when the reception of angle signals is missing at the control unit configured to provide steering signals, the actual steering angle is estimated based on sensor signals characterizing the motion of the motor vehicle provided by at least one sensor unit, and at least one actuator unit is set or adjusted based on the estimation of the actual steering angle so as to preset or control a theoretical trajectory preset based on the steering signals and / or the safe operation of the motor vehicle.

[0009] For example, the control unit includes an electronic computing unit and can be configured to provide driver assistance or a driver assistance system. Furthermore, the control unit can be configured to convert movement at the steering wheel into a steering signal. Therefore, the steering signal presets a theoretical steering angle, and through this theoretical steering angle, additionally presets a theoretical trajectory, for example, based on the vehicle speed, the vehicle should move along this theoretical trajectory based on the driver's intention or preset by the driver assistance system.

[0010] For example, the sensor unit providing sensor signals characterizing the motion of a motor vehicle can be an acceleration sensor, thus serving as at least one sensor signal, for example, providing the vehicle's yaw rate. Furthermore, the sensor unit can have, for example, a gyroscope and / or a tachometer, thereby allowing the motion of the motor vehicle to be estimated, for example, via or based on the sensor signals (e.g., through an odometer). Based on this estimation, or particularly through motion determination by the control unit based on the sensor signals, the actual steering angle can be estimated. If the actual steering angle is known, the difference and thus deviation from the theoretical trajectory can be estimated based on a theoretical angle preset by the steering signal.

[0011] Now, in this method, at least one actuator unit is configured based on the difference. This actuator unit can be, for example, the braking system of a motor vehicle, which is particularly capable of individually braking each tire of the vehicle. Thus, by manipulating the actuator unit, the difference between the actual trajectory and the theoretical trajectory can be reduced, thereby attempting, in particular, to achieve the theoretical trajectory without using the steering unit. If the difference is too large, or especially if the difference exceeds a threshold, a safe operation of the motor vehicle can be preset or initiated, which can be, for example, braking or emergency braking.

[0012] In other words, the process involves determining whether the angle signal, particularly the sensor signal status including the steering unit, is being forwarded by the sensor unit or received at the receiving location of the control unit. If this is not the case, the missing angle signal is estimated using vehicle-related sensors (specifically corresponding to the actuators of the vehicle or at least one or more actuator units). Based on this estimation, available actuators or actuators are used to maintain the vehicle's reference or theoretical trajectory, for example, by performing rear-wheel steering and / or asymmetric braking.

[0013] In other words, the failure of the steering unit's sensor unit is compensated for by reading sensor signals from other actuators and using them to determine the trajectory or theoretical steering angle. The advantage of this is that the vehicle can be at least conditionally kept in the lane, or can continue to travel along its theoretical trajectory, by configuring or operating at least one actuator unit to influence the theoretical trajectory in a way that compensates for the lack of a new steering signal setting. Furthermore, this results in particularly safe vehicle operation by avoiding deviations from the theoretical trajectory, or initiating safe operation even in cases of excessive deviation.

[0014] In an advantageous embodiment of the invention, at least one sensor signal characterizing the motion of the motor vehicle includes yaw rate and / or slip angle and / or wheel speed and / or rear wheel steering rod position. In other words, the actual steering angle can be estimated based on the yaw rate, slip angle, wheel speed, or rear wheel steering rod position. Thus, yaw describes the rotation of the motor vehicle and its vertical axis, from which the steering angle can be derived. The slip angle describes the angle between the velocity vector of the motor vehicle and the line of intersection of the wheel center plane and the road plane. For example, the lateral guiding force and / or restoring torque can be determined via the slip angle, from which the actual steering angle can be estimated. Especially when the wheelset of the steering unit is mounted at the front axle, the steering angle of the rear wheels is known based on the rear wheel steering rod position, from which the actual steering angle of the motor vehicle can be estimated. An advantage derived from the examples of the sensor signals (which should by no means be considered exhaustive) is that the steering angle can be estimated in a particularly simple and / or accurate manner, thereby allowing for particularly advantageous operation of the motor vehicle.

[0015] In another advantageous embodiment of the invention, the angle signal describes the position of the connecting rod (e.g., rack) of the steering unit, and / or the wheelset is arranged at the front axle of the vehicle. In other words, the steering unit is configured such that the steering angle of the wheelset is preset by moving the connecting rod or rack, for example, by means of a servo unit of the steering unit, thereby determining or presetting the angle signal by the position of the connecting rod or rack. Additionally or alternatively, the wheelset whose steering angle is preset or should be set by the steering signal is the wheelset of the front axle of the vehicle, thus the steering unit is, in particular, a conventional steering unit. The resulting advantage is that the method can be performed using a conventional steering unit, thus eliminating the need to construct a special steering unit at the vehicle. The resulting advantage is, for example, that the method can be performed particularly cost-effectively.

[0016] A rack is understood as a connecting rod with a toothed section, which has teeth.

[0017] For this method, the following design is advantageous, wherein the actuator unit, or at least one actuator unit, includes a braking device and / or a rear wheel steering device and / or a spoiler element and / or a drive system. Thus, the configuration of the actuator unit describes, in particular, asymmetrical braking of at least one front wheel and / or rear wheel, the steering angle of the rear wheel pair or rear wheel steering, and / or the retraction and / or extension of the spoiler element, and / or the deceleration or acceleration of at least one front wheel and / or rear wheel. In other words, by braking at least one wheel, front wheel, and / or rear wheel of the motor vehicle through the braking device or the drive system in the form of a motor brake, the actual trajectory of the motor vehicle can be affected, especially by asymmetrical braking of each wheel. An additional or alternative steering device for steering the front axle wheel pair, with a rear wheel steering device preset at the steering angle of the rear axle wheel pair, can similarly affect the actual trajectory. Furthermore, it is conceivable that at least one extendable spoiler element (e.g., an airfoil element) can be moved asymmetrically, or different spoiler elements can be provided for the left and / or right sides of the vehicle, thereby achieving the same effect on the actual trajectory through targeted movement of the spoiler elements. The advantage of this is that the theoretical trajectory can be achieved in a particularly advantageous manner.

[0018] In another advantageous embodiment of the invention, safe operation includes the slowing down of the entire motor vehicle, and in particular, its coming to a stop. In other words, safe operation induces a particularly uniform deceleration and thus braking of the motor vehicle, which should bring the vehicle to a controlled stop. Thus, safe operation can be provided, for example, through an emergency braking assist system. The resulting advantage is that the motor vehicle can be operated with exceptional safety.

[0019] In another advantageous embodiment of the invention, the driving conditions of the vehicle are acquired by means of environmental sensors, and the actuator unit settings are adapted according to the acquired driving conditions. In other words, the vehicle has environmental sensors (e.g., a camera with a panoramic camera or two camera units in particular) to acquire the vehicle's environment, and the driving conditions can be determined or evaluated, for example, by means of computer vision technology. Here, the data attached to the environmental sensors (such as camera images) can be used to determine or acquire the driving conditions using sensor signals from at least one sensor unit. Now, the actuator unit settings can be adapted according to the driving conditions. For example, if the vehicle is on a multi-lane road (which is well visible and not occupied by other vehicles or road users), the actuator unit can be set to achieve the theoretical trajectory as accurately as possible, even if the difference from the actual trajectory is large. For example, if the road is narrow and / or there are many other road users, safe operation can be initiated instead. The advantage of this is that the vehicle can be operated particularly safely.

[0020] In an advantageous design of a method for operating a motor vehicle, an adapted steering signal is preset before the actuator unit is set, and then the estimation of the actual steering angle is repeated. In other words, after the angle signal fails or is missing, it is checked whether the steering unit responds to correction or confirmation of the steering angle after the first estimation of the actual steering angle has been performed. Here, if it is determined that the steering unit still responds to the steering signal despite the absence of the angle signal, then instead of an actuator unit, the theoretical trajectory can be maintained by a steering unit that also includes an actuator. The advantage of this is that the theoretical trajectory can be achieved in a particularly advantageous manner.

[0021] In another advantageous embodiment of this method, the vehicle is operated in a manual and / or autonomous mode during its execution. In other words, during operation, the vehicle is manually controlled by the driver, particularly in steering. Additionally or alternatively, a driver assistance system is capable of operating the vehicle at least partially autonomously, such as, for example, lateral guidance of the vehicle. The advantage of this is that the described method can be used with particular flexibility in operating the vehicle, since it is not important whether the vehicle is operated manually or autonomously.

[0022] In another advantageous design of this method, a preset safe operating procedure is established based on an actual trajectory or the difference between the actual trajectory and the theoretical trajectory. In other words, the actual trajectory (which can be estimated based on at least one sensor signal) achievable by setting the actuator unit is compared with the theoretical trajectory that is actually expected (which is based on traffic conditions that should be maintained), and the difference or difference value is determined based on this comparison. If the difference value reaches or exceeds a particularly specific preset size, the execution of safe operating procedures is initiated. Thus, if the actual trajectory deviates significantly from the theoretical trajectory, emergency braking of the vehicle can be triggered, for example. The advantage of this is that the vehicle can be operated with exceptional safety.

[0023] A second aspect of the invention relates to a motor vehicle. The motor vehicle according to the second aspect of the invention includes a steering unit configured to preset a steering angle of a wheel pair based on a steering signal and to provide an angle signal characterizing the actual steering angle of the wheel pair. Furthermore, the motor vehicle includes: a control unit configured to provide a steering signal or preset a theoretical steering angle; a sensor unit that can provide sensor signals characterizing the motion of the motor vehicle; and an actuator unit that can preset the motion of the motor vehicle.

[0024] According to the present invention, when the angle signal is not received at the control unit, the actual steering angle is estimated based on at least one sensor signal, and the actuator unit is configured according to the estimation such that a theoretical trajectory can be preset, especially based on the steering signal, and / or the safe operation of the vehicle can be achieved.

[0025] Hereinafter, the advantageous designs, improvements, and advantages of the first aspect of the invention should be regarded as the advantageous designs, improvements, and advantages of the second aspect of the invention, and vice versa. Attached Figure Description

[0026] Other advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the accompanying drawings. The features and combinations of features mentioned above in the specification, as well as the features and combinations of features mentioned below in the description of the drawings and / or shown separately in the figures, may be used not only in the combinations given but also in other combinations or individually, without departing from the scope of the invention.

[0027] in: Figure 1 A schematic top view of a motor vehicle with a steering unit is shown; and Figure 2 It shows the method for running according to Figure 1 A schematic flowchart illustrating the method for handling motor vehicles. Detailed Implementation

[0028] Figure 1 A schematic top view of a motor vehicle 10 with a steering unit 12 is shown. This steering unit is configured to preset the steering angle of the wheel pair 14 based on a steering signal, for example, output by a control unit 16; that is, to set the steering angle of the wheel pair 14, in particular, to the actual steering angle. Furthermore, the steering unit 12 is configured to provide or output an angle signal characterizing the actual steering angle of the wheel pair 14. The motor vehicle 10 also includes a control unit 16 configured to provide a steering signal that presets or should preset a theoretical steering angle. Additionally, the motor vehicle 10 includes a sensor unit 18 through which sensor signals characterizing the motion of the motor vehicle 10 can be provided.

[0029] In order for the vehicle 10 to compensate for the lack of angle signal at the control unit 16 (e.g., due to sensor failure of the steering unit 12), the vehicle 10 is configured to estimate the actual steering angle based on at least one sensor signal from the sensor unit 18 when the angle signal is not received at the control unit 16, and to set at least one actuator unit 20 according to the estimate so that a theoretical trajectory 22 based on the steering signal or in principle preset and / or the safe operation of the vehicle 10 can be preset or controlled.

[0030] Therefore, it can be based on Figure 1 The motor vehicle shown is used to introduce Figure 2 The method described in the flowchart is used to operate a motor vehicle 10, which includes a steering unit 12 configured to preset the steering angle of a wheel pair 14 based on a steering signal and to provide an angle signal characterizing the actual steering angle of the wheel pair 14. In this method, when the angle signal is not received at a control unit 16 configured to provide the steering signal, the actual steering angle is estimated based on sensor signals characterizing the motion of the motor vehicle, provided at least by a control unit 18, and at least one actuator unit 20 is configured based on this estimation to preset or adjust a theoretical trajectory 22 or a preset theoretical trajectory based on the steering signal and / or to ensure the safe operation of the motor vehicle 10.

[0031] To this end, the flowchart illustrates three steps S1, S2, and S3, wherein, in step S1, it is checked whether an angle signal is received at the control unit 16, and if the signal is missing, the actual steering angle is estimated by means of step S2 based on at least one sensor signal characterizing the motion of the vehicle 10. Subsequently, in step S3, at least one actuator unit 20 is configured according to the estimation such that the vehicle 10 is moved or controlled in such a way that a preset theoretical trajectory 22 is achieved, or if the theoretical trajectory cannot be achieved, safe operation is preset or initiated.

[0032] It is advantageous to preset the adapted steering signal by the control unit 16 as an intermediate step of the method described in step 3 before setting the actuator unit, and then repeat the estimation. This can check whether the steering unit 12 still responds to the steering signal in the absence of the angle signal, so that the steering unit 12 can be used to achieve the theoretical trajectory 22.

[0033] Also advantageously, the sensor signals characterizing the motion of the vehicle 10 include yaw rate and / or slip angle and / or wheel speed and / or rear wheel steering rod position. Thus, at least one sensor unit 18 can be designed, for example, as an accelerometer and / or gyroscope, tachometer, steering angle sensor, etc. For example, the yaw rate describes the yaw 28 of the vehicle 10, which is shown by an arrow describing the rotation of the vehicle 10 about its vertical axis, from which the actual steering angle can be derived, for example. Similarly, the actual steering angle can be inferred via the wheel speeds, particularly the individual wheel speeds of each wheel 30 of the front wheel pair 14 and the rear wheel pair 32.

[0034] Actuator units 20 capable of advantageously influencing the movement or trajectory of motor vehicle 10 include, for example, braking devices 24 and / or rear wheel steering devices 26 and / or spoiler elements and / or drive systems. Thus, by providing at least one actuator unit 20, the movement of motor vehicle 10 can be influenced such that motor vehicle 10 can move along a theoretical trajectory 22.

[0035] Now, in order to influence the motion of the motor vehicle 10 and thus its actual trajectory to achieve the theoretical trajectory 22, the actuator unit can be configured in particular to perform asymmetrical braking or acceleration of the individual wheels 30 of the motor vehicle 10, as indicated by arrow 34, where the length of the arrow indicates the intensity of the corresponding deceleration and the corresponding braking of the corresponding wheel 30.

[0036] One advantageous design for the steering unit 12 is that the steering angle is preset by means of a connecting rod 36 configured as a rack, wherein the steering angle thus describes the position of the rack. Here, the wheelset 14 is advantageously arranged at the front axle 38 of the vehicle 10, thereby configuring the steering unit 12 as a conventional front axle steering device for the vehicle 10.

[0037] Safe operation may include, in particular, slowing down or bringing the vehicle 10 to a stop, and may be performed, for example, by a control unit 16 via an emergency braking assist system, which includes at least one electronic computing unit. Additionally, an environmental sensor 40 may be provided, through which the driving conditions of the vehicle 10 can be estimated, particularly in combination with sensor signals from at least one sensor unit 18, and the settings of at least one actuator unit 20 can be adapted based on the acquired driving conditions, or a distinction can be made between setting the actuator unit 20 and preset safe operation. Furthermore, it has proven advantageous to determine the difference between the actual trajectory and the theoretical trajectory 22, and to determine whether to set at least one actuator unit 20 and / or activate safe operation based on the magnitude of the difference.

[0038] The vehicle 10 can operate in a manual operating state (where the driver guides the vehicle 10) and / or in a state of at least partial autonomous operation (where the vehicle 10 is controlled by a driver assistance system), so the method is equally suitable for both manual and autonomous operation of the vehicle 10.

[0039] What can be achieved by the vehicle 10 and the method is that, in particular, the vehicle 10 configured as a passenger car will not become uncontrollable when the position of the steering actuator (which is, for example, the servo mechanism of the steering unit 12) is unknown. Thus, by collecting information in the form of at least one sensor unit 18 in the form of at least one sensor signal, and determining the actual steering angle based on this information, countermeasures can be taken by setting at least one actuator or actuator unit 20 or by performing safe operation to ensure the controllability and / or stability of the vehicle 10.

[0040] List of reference numerals 10 Motor vehicles 12 Steering Units 14 wheel pairs 16 Control Unit 18 sensor units 20 actuator units 22 Theoretical Trajectory 24 Braking device 26 Rear wheel steering system 28. Sideways 30 wheels 32 rear wheel sets 34 arrows 36 Connecting rods 38 Front Axle 40 Environmental Sensors S1 First Step S2 Second Step S3 Third step.

Claims

1. A method for operating a motor vehicle (10) having a steering unit (12), the steering unit being configured to preset the steering angle of a wheel pair (14) based on a steering signal and to provide an angle signal characterizing the actual steering angle of the wheel pair (14). in, When the angle signal is not received at the control unit (16) configured to provide the steering signal, the actual steering angle is estimated based on at least one sensor signal characterizing the motion of the motor vehicle (10) provided by the sensor unit (18). And at least one actuator unit (20) is configured in such a way as the estimation is such that a theoretical trajectory (22) is preset based on the steering signal and / or the safe operation of the motor vehicle (10).

2. The method according to claim 1, Its features are, The at least one sensor signal includes yaw rate and / or slip angle and / or wheel speed and / or rear wheel steering rod position.

3. The method according to claim 1 or 2, Its features are, The angle signal describes the position of the connecting rod (36) of the steering unit (12) and / or the wheel pair is located at the front axle (38) of the motor vehicle (10).

4. The method according to any one of the preceding claims, Its features are, The at least one actuator unit (20) includes a braking device (24) and / or a rear wheel steering device (26) and / or a spoiler element and / or a drive system, and the configuration of the actuator unit describes the braking and / or acceleration of at least one front wheel and / or rear wheel, the steering angle of the rear wheel pair (32) and / or the retraction and / or extension of the spoiler element.

5. The method according to any one of the preceding claims, Its features are, The safe operation includes the slowing down of the entire motor vehicle (10).

6. The method according to any one of the preceding claims, Its features are, The driving conditions of the motor vehicle (10) are obtained by means of environmental sensors, and the settings of the at least one actuator unit (20) are adapted according to the obtained driving conditions.

7. The method according to any one of the preceding claims, Its features are, Before setting the at least one actuator unit (20), an adapted steering signal is preset, and the estimation is then repeated.

8. The method according to any one of the preceding claims, Its features are, The motor vehicle (10) is operated in manual mode and / or autonomous mode.

9. The method according to any one of the preceding claims, Its features are, The preset safe operation is based on the difference between the actual trajectory and the theoretical trajectory (22).

10. A motor vehicle (10) comprising: a steering unit (12) configured to preset a steering angle of a wheel pair (14) based on a steering signal and to provide an angle signal characterizing the actual steering angle of the wheel pair (14); a control unit (16) configured to provide the steering signal; a sensor unit (18) providing sensor signals characterizing the motion of the motor vehicle (10); and at least one actuator unit (20) capable of presetting the motion of the motor vehicle (10). in, The motor vehicle (10) is configured to estimate the actual steering angle based on the at least one sensor signal when the angle signal is not received at the control unit (16), and to set the at least one actuator unit (20) according to the estimate such that a theoretical trajectory (22) preset based on the steering signal and / or the safe operation of the motor vehicle (10) can be preset.

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