Steering assistance system for a vehicle, method, computer-readable storage medium

Abstract

One aspect of the invention relates to a steering assistance system for a vehicle, comprising a steering wheel which is designed to provide steering wheel data that describe a current hand position of a driver of the vehicle. Furthermore, the steering assistance system comprises a processing device which is designed to receive steering wheel data from the steering wheel, to receive trajectory data that describe a trajectory of the vehicle, to determine a motor torque depending on the steering wheel data and the trajectory data, and finally to provide a control signal that describes the motor torque. The steering assistance system also comprises an electric motor for a steering mechanism of the vehicle, which is designed to receive the control signal and to generate a torque at the level of the motor torque.

Description

[0001] STEERING ASSISTANCE SYSTEM FOR A VEHICLE, METHOD,

[0002] COMPUTER-READABLE STORAGE MEDIUM

[0003] The present invention relates to a steering assistance system for a vehicle. Furthermore, the present invention relates to a method for operating a steering assistance system of a vehicle. Finally, the present invention also relates to a computer-readable storage medium.

[0004] Modern vehicles are equipped with a multitude of sensors for detecting the surroundings. Radar sensors and cameras can detect obstacles, for example, and initiate emergency braking if necessary (emergency brake assist). Furthermore, the radar sensors and cameras can determine the distance to vehicles ahead, which can be used for adaptive cruise control (ACC).

[0005] In addition, modern vehicles often feature so-called evasive steering assistants. If an obstacle is detected along with a (hectic) steering maneuver based on data provided by radar sensors or a camera, the driver can be assisted in an evasive maneuver by the torque of an electric motor in the steering gear. The motor torque can both increase or decrease the driver's steering torque, thus correcting the driver's steering angle. However, it is important that the driver initiates the steering and thus specifies the evasive direction. This makes the vehicle more agile during steering and stabilizes it again in the evasive trajectory thanks to dynamic stability control.

[0006] The first evasive action assistants have only been in series production for a few years, offering considerable development potential. For example, it's conceivable that future evasive action assistants could be even better adapted to the driver's needs and / or the current driving situation.

[0007] An evasive maneuver assistant is described, for example, in document DE 102014206 338 A1. This discloses a method and a corresponding device for assisting a driver of a vehicle during an evasive maneuver. A control unit for a vehicle is also described. The control unit is configured to detect an obstacle on a current trajectory of the vehicle and to determine an evasive trajectory for the vehicle to avoid the obstacle. The control unit is further configured to determine, at a first point in time, a first indication of the initiation of an evasive maneuver by a driver of the vehicle and, depending on the determined first indication and the determined evasive trajectory, to initiate assistance for the evasive maneuver.Furthermore, the control unit is configured to determine, at a second point in time, a second indication that an evasive maneuver has not been initiated. The second point in time follows the first point in time. The control unit is then configured to abort support of the evasive maneuver depending on the determined second indication.

[0008] Independently of this, document DE 101 48 535 A1 discloses a method for detecting the steering readiness or steering behavior of the driver of a motor vehicle, wherein at least one pressure and / or touch sensor, which delivers an electrical signal upon contact and / or pressure being exerted, is integrated into the steering wheel of the vehicle or attached to the steering wheel. The pressure and / or touch sensor has a plurality of sensor elements or segments arranged along the circumference of the steering wheel. Each of the sensor elements or segments has a plurality of pressure- and / or touch-sensitive zones in the cross-section of the steering wheel rim, so that it can be detected whether the driver's hand is gripping the steering wheel from the inside, outside, above or below. With the help of a signal representing the steering readiness, an evaluation unit can, for example, generate an acoustic, optical, haptic or similar warning depending on the current driving situation orof the traffic situation detected around the vehicle to the driver.

[0009] It is an object of the present invention to show a solution how a steering assistance system, in particular an evasive steering assistant, can be improved.

[0010] This object is achieved by the features of the independent claims. Further advantageous embodiments of the invention are specified in the dependent claims.

[0011] In this document, the term "automated driving" refers to driving with automated longitudinal and / or lateral guidance. Automated driving can, for example, involve extended driving on the highway or limited-time driving while parking. The term "automated driving" encompasses automated driving with any degree of automation. Examples of levels of automation are assisted, partially automated, conditionally automated, highly automated, and fully automated driving (with increasing levels of automation in each case). The five levels of automation mentioned above correspond to SAE Levels 1 to 5 of the SAE J3016 standard (SAE - Society of Automotive Engineering) as of April 30, 2021. In assisted driving (SAE Level 1), the system performs longitudinal or lateral guidance in specific driving situations.In partially automated driving (SAE Level 2), the system assumes longitudinal and lateral guidance in certain driving situations, whereby the driver must continuously monitor the system, as in assisted driving. In conditionally automated driving (SAE Level 3), the system assumes longitudinal and lateral guidance in certain driving situations without the driver having to continuously monitor the system; however, the driver must be able to assume control of the vehicle within a certain period of time upon request from the system. In highly automated driving (SAE Level 4), the system assumes control of the vehicle in certain driving situations, even if the driver does not respond to a request for intervention, thus eliminating the driver as a fallback. In fully automated driving (SAE Level 5), the system can perform all aspects of the dynamic driving task under any road and environmental conditions that can also be mastered by a human driver.

[0012] Furthermore, the term "at least partially automated driving or maneuvering" is also understood in this document to include partially automated, conditionally automated, highly automated, and fully automated driving. In other words, the term "at least partially automated driving" refers to a level of automation up to and including SAE Level 2.

[0013] A first aspect of the invention relates to a steering assistance system for a vehicle, comprising a steering wheel configured to provide steering wheel data describing a current hand position of a driver of the vehicle. Furthermore, the steering assistance system comprises a computing device configured to receive the steering wheel data from the steering wheel, receive trajectory data describing a trajectory of the vehicle, determine an engine torque as a function of the steering wheel data and the trajectory data, and finally provide a control signal describing the engine torque. The steering assistance system also comprises an electric motor for a steering gear of the vehicle, configured to receive the control signal and generate a torque equal to the engine torque.

[0014] The steering assistance system therefore serves to support the driver. In particular, the steering assistance system can vary the stiffness of the steering. The driver's hand position can be a key factor in this. In other words, the steering stiffness can be varied depending on whether the driver is securely gripping the steering wheel with two hands, for example, or whether the driver has only one hand on the steering wheel.

[0015] Steering stiffness describes the resulting force on the steering that the driver can feel. The resulting force or torque comprises the torque from the manual torque and the motor torque. The manual torque is the torque that the driver applies to a steering torsion bar by steering. The motor torque is the torque that an assisted or automated steering function applies to the steering torsion bar via a motor.

[0016] It is often observed that the driver of a vehicle has only one hand on the steering wheel. Typically, the hand is placed only on the upper semicircle of the steering wheel. This can lead to the driver's less confident control of the vehicle's lateral steering and, due to this hand position, may require more assistance in steering the vehicle laterally.

[0017] The steering wheel of the steering assistance system can detect various hand positions and describe them using the steering wheel data. The steering wheel can be equipped with a plurality of capacitive and / or resistive sensors. For example, a driver's hand—if it comes into contact with the steering wheel—can be detected by its influence on an electric field generated by the capacitive sensor. Different hand positions can be detected by the arrangement of the respective sensors.

[0018] The computer unit of the steering assistance system can then receive the steering wheel data and determine any required steering assistance using the motor torque depending on the trajectory to be traveled. The control signal can then be transmitted to the electric motor of the steering gear. The motor torque can be used to change the stiffness of the steering gear or the vehicle's steering. In certain situations, for example if the driver does not grip the steering wheel securely, the stiffness of the steering can be increased so that more force (i.e., a greater steering torque must be applied by the driver) is required to control lateral guidance. If the grip is not secure, the stiffness can be increased to provide the driver with greater support. The stiffness of the steering can also be reduced.The latter is particularly suitable when the driver holds the steering wheel securely in a quarter-to-three or ten-to-two position. With a secure grip, the stiffness can be reduced, for example, to provide less support to the driver and offer the driver a more cooperative maneuver.

[0019] For example, increasing stiffness can result in a higher steering torque being felt by the driver when the trajectory deviates from a target curvature. Reducing stiffness can result in a lower steering torque being felt when the driver essentially follows the (required) target curvature. In principle, the steering feel can be identical to manual driving when the stiffness is 0%. The stiffness can generally range from 60% to 100%, for example.

[0020] One embodiment of the steering assistance system provides that the steering wheel data describes a grip type of the driver's current hand position, which at least distinguishes between grasping and merely touching the steering wheel. Distinguishing between grasping and merely touching the steering wheel can be crucial for how safely the driver can control the vehicle's lateral steering. If the driver merely touches the steering wheel, greater assistance may be required for lateral steering. If the driver merely touches the steering wheel, the driver may only be able to apply a lower steering torque to the steering wheel. This can be compensated for by increasing the engine torque. Overall, safety can thus be increased.

[0021] Recognition of the grip type of the driver's current hand position can be achieved, for example, using the steering wheel presented in DE 101 48 535 A1.

[0022] For this purpose, the steering wheel can have a touch sensor comprising a plurality of sensor elements or segments arranged along the circumference of the steering wheel. Each of the sensor elements or segments can, in turn, have a plurality of pressure- and / or touch-sensitive zones in the cross-section of the steering wheel rim, so that, for example, it can be detected whether the driver's hand is grasping the steering wheel from the front and back, thus encircling it.

[0023] It can be advantageous if the motor torque is higher if the steering wheel data describes a mere touch of the steering wheel, or lower if the steering wheel data describes a grip on the steering wheel. In particular, the motor torque can also have a direction (or a sign). In other words, the motor torque can have a supporting effect, for example, in the case of a mere touch. In the case of a secure grip, the motor torque can also act in the opposite direction to the driver's steering torque, which can increase the stiffness of the steering.

[0024] Additionally or alternatively, it can be provided that the steering wheel data describes a grip position of the driver's current hand position, wherein the grip position describes a current position of at least one of the driver's hands on the steering wheel and characterizes the current position based on predetermined steering wheel zones. Distinguishing the current position of the driver's hand or hands can also be decisive for how safely the driver can control the vehicle's lateral steering. The position of the driver's hand or hands can be particularly decisive for the driver's maximum steering movement. In the quarter-to-three or ten-to-two position, the driver can turn the steering wheel 180°, for example, and thus react as best as possible even in critical situations. However, if the driver only has one hand on the steering wheel - often on the top side - their maximum steering movement is significantly limited.

[0025] By describing the current position of at least one of the driver's hands on the steering wheel and characterizing it using predetermined steering wheel zones, the driver can be optimally supported in lateral steering depending on the hand position. This can significantly increase safety.

[0026] The predetermined steering wheel zones can be configured in a wide variety of ways. For example, two zones (left and right) can be used to characterize the quarter-to-three position or the ten-to-two position. A further zone on the top can be used, for example, to characterize the so-called dishwasher or windshield wiper position. Furthermore, additional zones are also conceivable that describe other hand positions of the driver. It can be particularly advantageous if the predetermined steering wheel zones comprise at least three different zones. Using just three steering wheel zones, most hand positions can be reliably characterized. Furthermore, an unnecessarily large number of sensors are not required.

[0027] A further embodiment provides that the computing device of the steering assistance system is additionally configured to receive acute warning data describing a critical driving situation and to assist the driver in an evasive maneuver using the engine torque. An evasive maneuver represents a particularly critical situation in road traffic. If the driver holds the steering wheel incorrectly or uses an incorrect hand position, their range of motion and / or the maximum possible steering torque may be restricted. In such situations, the driver requires particularly targeted assistance to control the vehicle.

[0028] If such a critical situation is detected by a vehicle assistance system, the acute warning data can be forwarded to the computer unit of the steering assistance system. The steering assistance system can be configured to provide the (supporting) engine torque for the vehicle's steering gear only in a situation described by the acute warning data. However, it is equally conceivable that the steering assistance system only provides the (supporting) engine torque in situations not described by the acute warning data.

[0029] In this case, it may be advantageous if the computing device of the steering assistance system is additionally configured to receive steering torque data describing a driver-initiated steering movement and / or a driver-initiated steering torque. As described above, driver-initiated steering may be necessary, particularly with modern evasive steering systems, for the driver to specify the evasive direction. This can also ensure consent to leave the lane.

[0030] The engine torque can essentially both increase and decrease the driver's steering torque, thus correcting or assisting the driver's steering angle and changing the stiffness of the steering. Although the driver's hand position can be an important indicator of the maximum possible steering movements and torque, the additional steering torque data can ensure finer tuning of the steering assistance system.

[0031] Finally, it can also be advantageous if the computing unit of the steering assistance system is configured to determine a target steering torque based on the vehicle's trajectory and to additionally determine the engine torque based on the steering torque data and the target steering torque. For example, a trajectory can be determined in advance for an evasive maneuver. Based on the vehicle's current speed, future forces (lateral acceleration, etc.) can be determined in advance. Based on these forces, a required target steering torque can be determined, which is necessary to follow the trajectory.

[0032] The engine torque required to assist the evasive maneuver can now also be determined based on the initial steering torque applied by the driver. The engine torque can either increase or decrease the driver's steering torque, thus supporting or correcting the driver's steering angle. This can further increase safety.

[0033] A further aspect of the invention relates to a method for operating a steering assistance system of a vehicle. The method comprises receiving steering wheel data from a steering wheel of the vehicle, wherein the steering wheel data describe a current hand position of a driver of the vehicle. Furthermore, the method comprises receiving trajectory data describing a trajectory of the vehicle. Furthermore, the method comprises determining a motor torque as a function of the steering wheel data and the trajectory data, wherein the motor torque describes a torque for assisting a steering movement of the driver. Finally, the method comprises providing a control signal describing the motor torque.

[0034] The method can be carried out, for example, using a computing device. The computing device can be embodied, for example, as at least one electronic control unit of the vehicle, which comprises one or more programmable processors. Furthermore, the computing device can have a computer-readable storage medium on which a computer program is stored. In order to carry out corresponding method steps, such as determining the engine torque as a function of the steering wheel data and the trajectory data, the computer program can be executed on the computing device.

[0035] A further aspect of the invention relates to a computer-readable storage medium comprising instructions which, when executed by a computing device, cause the computing device to carry out a method for operating a steering assistance system and the advantageous embodiments thereof.

[0036] The invention also relates to a computer program comprising instructions that, when executed by a computing device, cause the device to execute a method for operating a steering assistance system and the advantageous embodiments thereof. Furthermore, the invention relates to a vehicle comprising a steering assistance system according to the invention. The vehicle can be designed, in particular, as a passenger car.

[0037] The preferred embodiments presented with reference to the steering assistance system according to the invention and their advantages apply accordingly to the method according to the invention and to the computer-readable device according to the invention. Furthermore, the preferred embodiments presented with reference to the steering assistance system according to the invention and their advantages also apply to the computer program according to the invention and to the vehicle according to the invention.

[0038] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0039] The invention will now be explained in more detail using preferred embodiments and with reference to the accompanying drawings.

[0040] Fig. 1 is a schematic representation of a vehicle comprising a steering assistance system, Fig. 2 is a schematic representation of a steering wheel of a steering assistance system, which has different steering wheel zones for characterizing grip positions of a driver's hand position, and

[0041] Fig. 3a, b a schematic representation of different grip positions of a driver's hand position, which can be characterized by means of the steering wheel zones.

[0042] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0043] Fig. 1 shows a schematic representation of a vehicle 1, comprising a steering assistance system 2. The steering assistance system 2 comprises a steering wheel 3, a computing device 4 and an electric motor 5 for a steering gear 6 of the vehicle 1. The steering gear 6 is connected to the steering wheel 3 and the front wheels 7 of the vehicle 1.

[0044] The steering assistance system 2 can assist a driver of the vehicle 1 during a steering maneuver. In particular, the stiffness of the steering or steering gear 6 can be varied using the steering assistance system 2. This can be done depending on the driver's hand position 8.

[0045] For this purpose, the steering wheel 3 of the steering assistance system 2 can detect various hand positions 8 of the driver and describe them using steering wheel data. The steering wheel 3 can have a plurality of capacitive and / or resistive sensors.

[0046] Fig. 2 shows the steering wheel 3 of the steering assistance system 2. The steering wheel 3 has various steering wheel zones 9 for characterizing grip positions of a driver's hand position 8. The respective steering wheel zones 9 include corresponding touch sensors. Using the steering wheel zones 9A1 and 9A2, for example, a quarter-to-three position or a ten-to-two position of the driver's hand position 8 can be detected. A quarter-to-three position or a ten-to-two position can characterize a secure grip of the steering wheel 3 by the driver of the vehicle 1.

[0047] The steering wheel zone 9B1 can, for example, characterize a hand position 8, which is often referred to as a dishwasher or windshield wiper position. The steering wheel zone 9B2 can, for example, describe a hand position 8 in which the driver rests their arms on their thighs. A hand position in the steering wheel zones 9B1 and / or 9B2 often indicates a restricted range of motion in the event of a (hectic) steering maneuver. Therefore, a driver whose hand(s) are in such a hand position 8 may require different steering assistance than a driver whose hands are in the quarter-to-three position. Fig. 3a and Fig. 3b schematically show the two hand positions 8.

Claims

Claims 1. Steering assistance system (2) for a vehicle (1), comprising: - a steering wheel (3) which is designed to provide steering wheel data which describe a current hand position (8) of a driver of the vehicle (1), - a computing device (4) which is designed to ■ to receive the steering wheel data from the steering wheel (3), ■ to receive trajectory data describing a trajectory of the vehicle (1), ■ to determine an engine torque depending on the steering wheel data and the trajectory data, and ■ to provide a control signal that describes the motor torque, - an electric motor (5) for a steering gear (6) of the vehicle (1), which is designed to receive the control signal and to generate a torque equal to the engine torque.

2. Steering assistance system (2) according to claim 1, characterized in that the steering wheel data describe a grip type of the current hand position (8) of the driver, which distinguishes at least between grasping and merely touching the steering wheel (3).

3. Steering assistance system (2) according to claim 2, characterized in that the motor torque is greater if the steering wheel data describe a mere touching of the steering wheel (3), or the motor torque is lower if the steering wheel data describe a grasping of the steering wheel (3).

4. Steering assistance system (2) according to one of the preceding claims, characterized in that the steering wheel data describe a grip position of the current hand position (8) of the driver, wherein the grip position is a current position of at least one hand of the driver on the steering wheel (3) and characterizes the current position based on predetermined steering wheel zones (9).

5. Steering assistance system (2) according to claim 4, characterized in that the predetermined steering wheel zones (9) comprise at least three different zones.

6. Steering assistance system (2) according to one of the preceding claims, characterized in that the computing device (4) of the steering assistance system (2) is additionally configured to receive acute warning data describing a critical driving situation and to assist the driver in an evasive maneuver by means of the engine torque.

7. Steering assistance system (2) according to claim 6, characterized in that the computing device (4) of the steering assistance system (2) is additionally configured to receive steering torque data which describe a steering movement initiated by the driver and / or describe a steering torque of the driver.

8. Steering assistance system (2) according to claim 7, characterized in that the computing device (4) of the steering assistance system (2) is further configured to determine a desired steering torque as a function of the trajectory of the vehicle (1) and to additionally determine the engine torque as a function of the steering torque data and the desired steering torque.

9. Method for operating a steering assistance system (2) of a vehicle (1), comprising the steps: - receiving steering wheel data from a steering wheel (3) of the vehicle (3), wherein the steering wheel data describe a current hand position (8) of a driver of the vehicle (1), - receiving trajectory data describing a trajectory of the vehicle (1), - Determining a motor torque as a function of the steering wheel data and the trajectory data, wherein the motor torque describes a torque to support a steering movement of the driver, and - Providing a control signal that describes the motor torque.

10. A computer-readable storage medium comprising instructions which, when executed by a computing device (4), cause the computing device (4) to carry out a method according to claim 9.

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