DE102021129938A1 - METHOD, COMPUTER PROGRAM PRODUCT, DRIVING ASSISTANCE SYSTEM AND VEHICLE - Google Patents

Abstract

A method for operating a driver assistance system (110) for a vehicle (100) which has a trailer device (140) for coupling a trailer (200) to the vehicle (100) is proposed. The method includes:Reading out (S1) a stored trajectory (TRO), the stored trajectory (TRO) comprising a function of a target articulation angle (HA) as a function of a distance traveled (S), the articulation angle (HA) being an angle between a vehicle longitudinal axis (105) of the vehicle (100) and a trailer longitudinal axis (205) of the coupled trailer (200),detecting (S2) an actual articulation angle (HA) which indicates the articulation angle (HA) at a current position (P0, P1 - P17, P100) of the vehicle (100) with the trailer (200) coupled, causing (S3) reverse travel of the vehicle (100) with the trailer (200) coupled thereto, the vehicle (100) being so controlled during reverse travel that the actual articulation angle (HA) as a function of the distance covered (S) is equal to the setpoint articulation angle (HA) corresponding to the distance covered (S).

Description

The present invention relates to a method, a computer program product, a driver assistance system and a vehicle.

For many users who only occasionally drive a vehicle-trailer combination, driving the combination in tight quarters and backing up the combination is a challenge. Especially when reversing, the combination forms a pseudo-stable system, since if the trailer deflects from the direction of travel, the deflection of the trailer increases self-reinforcing without the vehicle adapting the direction of travel. The deflection of the trailer from the direction of travel can also occur suddenly due to small influences, such as different rolling resistance of the trailer wheels.

DE 10 2019 007 826 A1 discloses a method for operating a vehicle-trailer combination, in which a trailer is coupled to a towing vehicle by means of a drawbar, with trailer data, comprising at least one drawbar length, being determined during driving operation of the vehicle-trailer combination, the determined trailer data in the towing vehicle are stored and after a renewed activation of the driving operation the stored trailer data are made available to a trailer assistance system. Depending on the stored trailer data, an articulation angle of the trailer relative to the towing vehicle can be predicted for at least one specific driving maneuver and stored as a target articulation angle. An actual articulation angle is determined during driving when the driving maneuver is being carried out and is compared with the setpoint articulation angle. A previous change of trailer while the vehicle-trailer combination is not being driven is recognized if the actual articulation angle deviates from the setpoint articulation angle by a predetermined amount.

US20210170947A1 discloses a vehicle having a number of sensors that collect sensor data based on which an articulation angle between the vehicle and a trailer coupled to the vehicle is determined. A yaw rate for the vehicle and the articulation angle for a point in time in the future are also determined on the basis of the sensor data recorded. Furthermore, a corrected yaw rate and a corrected articulation angle as well as a respective orientation and a respective position of the vehicle and the trailer are determined on the basis of the sensor data.

Driving assistance systems are known which support the user when reversing without a trailer, for example by following a trajectory previously driven forward in the opposite direction. In this case, the driver assistance system can orientate itself, for example, with the help of recorded sensor data that depicts the surroundings of the vehicle. If a trailer is coupled to the vehicle, such reversing assistants cannot be used since the driving maneuvers to be carried out in order to drive a specific trajectory differ fundamentally from the situation without a coupled trailer. Furthermore, the view to the rear can be blocked by the trailer, so that a detection of sensor data that are indicative of the surroundings to the rear and by means of which the driver assistance system can orient itself is limited or not possible at all.

Against this background, an object of the present invention is to improve the operation of a driver assistance system.

• Auslesen einer gespeicherten Trajektorie, wobei die gespeicherte Trajektorie eine Funktion eines Soll-Knickwinkels in Abhängigkeit einer zurückgelegten Strecke umfasst, wobei der Knickwinkel ein Winkel zwischen einer Fahrzeuglängsachse des Fahrzeugs und einer Anhängerlängsachse des gekoppelten Anhängers ist,
• Erfassen eines Ist-Knickwinkels, der den Knickwinkel an einer aktuellen Position des Fahrzeugs mit gekoppeltem Anhänger darstellt,
• Veranlassen einer Rückwärtsfahrt des Fahrzeugs mit dem daran gekoppelten Anhänger, wobei das Fahrzeug während der Rückwärtsfahrt derart gesteuert wird, dass der Ist-Knickwinkel in Abhängigkeit der zurückgelegten Strecke gleich dem der zurückgelegten Strecke entsprechenden Soll-Knickwinkel ist.

According to a first aspect, a method for operating a driver assistance system for a vehicle that has a trailer device for coupling a trailer to the vehicle is proposed. The procedure includes:

• Reading out a stored trajectory, the stored trajectory comprising a function of a target articulation angle as a function of a distance covered, the articulation angle being an angle between a vehicle longitudinal axis of the vehicle and a trailer longitudinal axis of the coupled trailer,
• detecting an actual articulation angle, which represents the articulation angle at a current position of the vehicle with a coupled trailer,
• Initiating reverse travel of the vehicle with the trailer coupled to it, the vehicle being controlled during reverse travel in such a way that the actual articulation angle as a function of the distance covered is equal to the target articulation angle corresponding to the distance covered.

This method has the advantage that reversing with a trailer can be carried out automatically or autonomously, provided a corresponding stored trajectory is available. This is achieved by controlling the articulation angle depending on the route, which means that the stored trajectory is followed in the opposite direction, especially when reversing. This is in contrast to methods that include position control, which attempts to stay exactly on a predetermined trajectory based on the position of the vehicle and/or trailer. This completes the proposed Ver drive easier to carry out. In particular, the method can also be carried out with simpler sensor technology, since only the articulation angle and the distance covered have to be recorded.

The stored trajectory is stored, for example, permanently or only temporarily on a storage unit of the driver assistance system. The stored trajectory includes a function of the target articulation angle as a function of the distance covered. It can also be said that the trajectory comprises a number of positions with an associated kink angle, with a distance between any two consecutive positions being known.

When the method is carried out, in particular when reversing, the actual articulation angle is recorded regularly, for example every 100 ms, so that any deviation of the actual articulation angle from the target articulation angle can be detected and corrected at an early stage.

The current position relates in particular to a specific route traveled since the start of the journey. This means that at the start of the journey the current position corresponds in particular to the end point of the stored trajectory, and at the end of the journey it corresponds to the starting point of the stored trajectory. The position is, for example, a one-dimensional quantity that indicates a distance from the starting point or the ending point of the trajectory.

According to one embodiment of the method, the driver assistance system is set up to detect and store the trajectory during manual forward travel. The actual articulation angle is recorded as a function of the distance covered during forward travel and stored as the trajectory, with the actual articulation angle recorded being stored as the setpoint articulation angle as a function of the distance covered.

This has the advantage that a route driven forward can be automatically reversed at any time. In particular, the articulation angle can be temporarily stored as a function of the distance traveled at any time during forward travel, for example for the last 50 meters or 100 meters traveled, so that it is possible at any time to automatically reverse the last traveled distance.

In addition, in this embodiment, no further knowledge regarding the trailer, such as a geometry, in particular a length of a drawbar or a distance between a yaw point of the trailer and a coupling point, is necessary.

• Empfangen eines für den Ist-Knickwinkel indikativen Knickwinkel-Sensorsignals, und
• Ermitteln des Ist-Knickwinkels in Abhängigkeit des empfangenen Knickwinkel-Sensorsignals.

According to a further embodiment of the method, the distance covered is determined as a function of recorded odometry data, the odometry data being a wheel speed sensor signal, a wheel angle sensor signal, a steering angle sensor signal, an optical sensor signal of an area surrounding the vehicle and/or an ultrasonic sensor signal, which is indicative of an object in the area surrounding the vehicle, according to a further embodiment of the method, the detection of the actual articulation angle includes:

• receiving an articulation angle sensor signal indicative of the actual articulation angle, and
• Determining the actual articulation angle as a function of the articulation angle sensor signal received.

According to a further embodiment of the method, the articulation angle sensor signal comprises an optical sensor signal, an ultrasonic sensor signal and/or a rotation angle sensor signal.

The optical sensor signal is provided, for example, by a reversing camera, an all-round view camera and/or by a rear-facing radar and/or lidar. The trailer is therefore contained in particular in the optical sensor signal. The kink angle can be determined by appropriate processing of the optical sensor signal, for example by means of image processing. The surround view camera, which may also be referred to as a bird's eye view, specifically includes a composite image composed of individual images from multiple individual cameras.

A distance from the rear of a trailer to the vehicle can be determined on the basis of the ultrasonic sensor signal, the articulation angle being able to be derived if the geometry of the rear of the trailer is known.

In embodiments, the driver assistance system is set up to detect and store a parking trajectory of the vehicle with a coupled trailer during a parking process and to detect and store the articulation angle at a respective position of the parking trajectory. Furthermore, the driver assistance system is set up to automatically follow the stored parking trajectory forwards and backwards, with the driver assistance system controlling the vehicle in sections of the parking trajectory which are followed forwards when following the vehicle in such a way that the position of the vehicle corresponds to the stored position, and in sections the parking trajectory, which is followed backwards by the follower are, the vehicle controls such that the actual articulation angle matches the target articulation angle.

This has the advantage that the method can be used to provide a trainable parking function, in which the user of the vehicle follows a specific trajectory manually once, which can then be followed automatically by the driver assistance system (trained parking). In this embodiment, it is possible to automatically follow a complex trajectory that includes multiple trains.

For sections that are driven forward, there is a position control in particular, with the driver assistance system orienting itself towards objects in the environment, for example by means of VSLAM (visual simultaneous localization and mapping).

According to a second aspect, a computer program product is proposed which comprises instructions which, when the program is executed by a computer, cause the latter to execute the method according to the first aspect.

A computer program product, such as a computer program means, can be made available or supplied by a server in a network, for example, as a storage medium such as a memory card, USB stick, CD-ROM, DVD, or in the form of a downloadable file. This can be done, for example, in a wireless communication network by transferring a corresponding file with the computer program product or the computer program means.

The computer is designed in particular as a driver assistance system for a vehicle.

• eine Datenverarbeitungseinheit zum Auslesen einer gespeicherten Trajektorie, wobei die gespeicherte Trajektorie eine Funktion eines Soll-Knickwinkels in Abhängigkeit einer zurückgelegten Strecke umfasst, wobei der Knickwinkel ein Winkel zwischen einer Fahrzeuglängsachse des Fahrzeugs und einer Anhängerlängsachse des gekoppelten Anhängers ist,
• eine Erfassungseinheit zum Erfassen eines Ist-Knickwinkels, der den Knickwinkel an einer aktuellen Position des Fahrzeugs mit gekoppeltem Anhänger darstellt, und
• eine Steuereinheit zum Veranlassen einer Rückwärtsfahrt des Fahrzeugs mit dem daran gekoppelten Anhänger, wobei die Steuereinheit dazu eingerichtet ist, das Fahrzeug während der Rückwärtsfahrt derart zu steuern, dass der Ist-Knickwinkel in Abhängigkeit der zurückgelegten Strecke gleich dem der zurückgelegten Strecke entsprechenden Soll-Knickwinkel ist.

According to a third aspect, a driver assistance system for a vehicle, which has a trailer device for coupling a trailer to the vehicle, is proposed. The driver assistance system has:

• a data processing unit for reading out a stored trajectory, the stored trajectory comprising a function of a target articulation angle as a function of a distance covered, the articulation angle being an angle between a vehicle longitudinal axis of the vehicle and a trailer longitudinal axis of the coupled trailer,
• a detection unit for detecting an actual articulation angle representing the articulation angle at a current position of the vehicle with the trailer coupled, and
• a control unit for initiating reversing of the vehicle with the trailer coupled to it, the control unit being set up to control the vehicle during reversing in such a way that the actual articulation angle as a function of the distance covered is equal to the setpoint articulation angle corresponding to the distance covered .

This driver assistance system has the same advantages as described for the method according to the first aspect. The embodiments and features described for the proposed method apply accordingly to the driver assistance system.

The respective unit of the driver assistance system can be implemented in terms of hardware and/or software. In the case of a hardware implementation, the respective unit can be embodied, for example, as a computer or as a microprocessor. In the case of a software implementation, the respective unit can be designed as a computer program product, as a function, as a routine, as an algorithm, as part of a program code or as an executable object. Furthermore, each of the units mentioned here can also be designed as part of a higher-level control system of the vehicle, such as a central electronic control device and/or an engine control unit (ECU: Engine Control Unit).

The stored trajectory is stored, for example, by a storage unit, which can be a temporarily stored or also a permanently stored trajectory.

According to a fourth aspect, a vehicle with a trailer device and with a driver assistance system according to the third aspect is proposed.

The vehicle is, for example, a passenger car or a truck. The vehicle preferably includes a number of sensor units that are set up to detect the driving state of the vehicle and to detect an environment of the vehicle. Examples of such sensor units of the vehicle are optical sensor units, such as a camera, a radar (radio detection and ranging) or a lidar (light detection and ranging), ultrasonic sensors, location sensors, wheel angle sensors and/or wheel speed sensors. The sensor units are each set up to output a sensor signal, for example to the driver assistance system.

Further possible implementations of the invention also include combinations of features or embodiments described above or below with regard to the exemplary embodiments that are not explicitly mentioned. The person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the invention.

• 1 zeigt eine schematische Ansicht eines Fahrzeugs mit einem gekoppelten Anhänger;
• 2 zeigt eine schematische Ansicht eines Beispiels für eine Trajektorie;
• 3 zeigt ein Diagramm für den Knickwinkel als Funktion der zurückgelegten Strecke;
• 4 zeigt ein schematisches Blockdiagramm eines Ausführungsbeispiels für ein Fahrassistenzsystem; und
• 5 zeigt ein schematisches Blockschaltbild eines Ausführungsbeispiels für ein Verfahren zum Betreiben eines Fahrassistenzsystems.

Further advantageous refinements and aspects of the invention are the subject matter of the dependent claims and of the exemplary embodiments of the invention described below. The invention is explained in more detail below on the basis of preferred embodiments with reference to the enclosed figures.

• 1 shows a schematic view of a vehicle with a coupled trailer;
• 2 shows a schematic view of an example of a trajectory;
• 3 shows a graph of articulation angle as a function of distance traveled;
• 4 shows a schematic block diagram of an exemplary embodiment of a driver assistance system; and
• 5 shows a schematic block diagram of an exemplary embodiment of a method for operating a driver assistance system.

Elements that are the same or have the same function have been provided with the same reference symbols in the figures, unless otherwise stated.

1 shows a schematic view of an example of a combination 300 comprising a vehicle 100 and a trailer 200 attached thereto from a bird's eye view. The vehicle 100 is, for example, a car with a front axle and a rear axle, the vehicle 100 having front-axle steering, as indicated by the pivoted wheels of the front axle. Vehicle 100 includes a driver assistance system 110, which is set up to drive vehicle combination 300 automatically, and sensor units 120, 130. This is, for example, a reversing camera 120 that captures an image of a rear area of vehicle 100 and transmits it as an optical sensor signal to the Driver assistance system 110 outputs, as well as ultrasonic sensors 130, each of which detects a distance from objects arranged behind vehicle 100 and outputs it to driver assistance system 110 as an ultrasonic sensor signal. Furthermore, the vehicle 100 has a trailer hitch 140 to which the trailer 200 is coupled. The longitudinal axis 105 of the vehicle 100 defines a specific, vehicle-fixed direction. In this example, the trailer 200 has only one wheel axle. The longitudinal axis 205 of the trailer 200 defines a specific trailer-fixed direction. The articulation angle HA is the angle enclosed by the longitudinal axis 105 of the vehicle and the longitudinal axis 205 of the trailer.

2 shows a schematic view of an example of a trajectory TR. This is, for example, a stored trajectory that the user of vehicle 100 drove forward with a trailer 200 attached to vehicle 100, with the articulation angle HA (see FIG 1 or 3 ) was recorded and stored as a function of the distance driven. The trajectory TR0 runs from an initial position P0 to an end position P100.

In this example, the trajectory TR0 comprises seventeen points P1-P17, with two consecutive positions, for example, each having a distance of one meter from one another. It should be noted that this is merely an example and the trajectory can also include more or fewer positions and the distances between two positions can also be smaller or larger and/or irregular. The articulation angle HA is stored for each position P1 - P17. The trajectory TR0 thus includes a function of the articulation angle HA of the route covered. The trajectory TR0 can also be represented as a distance-kink angle diagram, which is used for the 2 illustrated trajectory TR0 example in the 3 is shown.

The driving assistance system 110 (see 1 or 4 ) is set up to follow the trajectory TR0 backwards in the opposite direction with the vehicle combination 300 . In this case, driver assistance system 110 controls vehicle 100 in such a way that articulation angle HA at a respective position P1-P17 along trajectory TR0 corresponds to the setpoint articulation angle stored for the position. The position along the trajectory TR0 results from the path covered. If the distance between two positions is greater than a predetermined limit value, the target articulation angle between these positions can be interpolated. This enables the trajectory to be tracked more precisely, with the memory requirement for storing the trajectory being able to be kept low at the same time.

3 shows a diagram DIAG for the articulation angle HA as a function of the distance S covered. The curve HA(S) shown shows, for example, the course along the trajectory TR0 of 2 , where the articulation angle HA is 0° when driving straight ahead, assumes negative values for a right-hand bend and assumes positive values for a left-hand bend. On the horizontal axis representing the distance S covered, points P1 - P17 of the trajectory TR0 are plotted (in green in the overview, only points P1, P5, P10, P15 and P17 bear the reference number).

4 shows a schematic block diagram of an exemplary embodiment of a driver assistance system 110 for a vehicle 100, which has a trailer device for coupling a trailer 200 to the vehicle 100, for example the vehicle 100 of FIG 1 . Driver assistance system 110 includes a data processing unit 112 for reading out a stored trajectory TR0 (see 2 ), where the stored trajectory TR0 is a function of a target articulation angle HA (see 1 - 3 ) as a function of a distance S covered (see 3 ), wherein the articulation angle HA is an angle between a vehicle longitudinal axis 105 (see 1 ) of the vehicle 100 and a trailer longitudinal axis 205 (see 2 ) of the coupled trailer 200, a detection unit 114 for detecting an actual articulation angle HA, which represents the articulation angle HA at a current position of the vehicle 100 with the trailer 200 coupled, and a control unit 116 for causing the vehicle 100 to reverse with the trailer coupled thereto Trailer 200, wherein the control unit 116 is set up to control the vehicle 100 while reversing in such a way that the actual articulation angle HA as a function of the distance S covered is equal to the target articulation angle HA of the stored trajectory that corresponds to the distance S covered.

5 shows a schematic block diagram of an exemplary embodiment of a method for operating a driver assistance system 110 for a vehicle 100, which has a trailer device for coupling a trailer 200 to the vehicle 100, for example the vehicle 100 of FIG 1 and the driver assistance system 110 of 4 . In a first step S1, a stored trajectory TR0 (see 2 ) is read out, with the stored trajectory TR0 being a function of a target articulation angle HA (see 1 - 3 ) as a function of a distance S covered (see 3 ), wherein the articulation angle HA is an angle between a vehicle longitudinal axis 105 (see 1 ) of the vehicle 100 and a trailer longitudinal axis 205 (See 1 ) of the coupled trailer 200. In a second step S2, the actual articulation angle HA, which represents the articulation angle at a current position of the vehicle 100 with a coupled trailer 200, is detected. In a third step S3, vehicle 100 is reversed with trailer 200 coupled to it, vehicle 100 being controlled during reverse travel in such a way that actual articulation angle HA is equal to the setpoint corresponding to distance S covered, depending on distance S covered -kink angle HA is.

Although the present invention has been described using exemplary embodiments, it can be modified in many ways.

reference list

100

vehicle

105

longitudinal axis

110

driver assistance system

112

data processing unit

114

registration unit

116

control unit

120

sensor

130

sensor

140

hitch

200

Fan

205

longitudinal axis

300

team

DIAG

diagram

HA

kink angle

HA(S)

Function of the kink angle

P0

initial position

P1 - P17

position

P100

final position

S

Route

S1

process step

S2

process step

S3

process step

TR0

trajectory

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102019007826 A1 [0003]
• US20210170947A1 [0004]

Claims (8)

Method for operating a driver assistance system (110) for a vehicle (100), which has a trailer device (140) for coupling a trailer (200) to the vehicle (100), the method comprising: Reading out (S1) a stored trajectory (TRO), the stored trajectory (TRO) comprising a function of a target articulation angle (HA) as a function of a distance covered (S), the articulation angle (HA) being an angle between a vehicle longitudinal axis (105 ) of the vehicle (100) and a trailer longitudinal axis (205) of the coupled trailer (200), Detection (S2) of an actual articulation angle (HA), which represents the articulation angle (HA) at a current position (P0, P1 - P17, P100) of the vehicle (100) with a coupled trailer (200), Initiating (S3) reverse travel of the vehicle (100) with the trailer (200) coupled to it, the vehicle (100) being controlled during reverse travel in such a way that the actual articulation angle (HA) is the same as a function of the distance (S) covered is the target articulation angle (HA) corresponding to the distance covered (S). procedure after claim 1 , characterized in that the driving assistance system (110) is set up to detect and store the trajectory (TRO) during manual forward travel, with: detecting the actual articulation angle (HA) as a function of the distance (S) covered during forward travel, and storing of the trajectory (TRO), whereby the detected actual articulation angle (HA) is stored as the target articulation angle (HA) depending on the distance covered (S). procedure after claim 1 or 2 , characterized in that the distance covered (S) is determined as a function of recorded odometry data, the odometry data being a wheel speed sensor signal, a wheel angle sensor signal, a steering angle sensor signal, an optical sensor signal of an environment of the vehicle (100) and/or an ultrasonic sensor signal indicative of an object in the vicinity of the vehicle (100). Method according to one of the preceding claims, characterized in that detecting the actual articulation angle (HA) comprises: receiving an articulation angle sensor signal indicative of the actual articulation angle (HA), and determining the actual articulation angle (HA) as a function of the received signal kink angle sensor signal. procedure after claim 4 characterized in that the kink angle sensor signal comprises an optical sensor signal, an ultrasonic sensor signal and/or a rotation angle sensor signal. Computer program product, comprising instructions which, when the program is executed by a computer, cause the latter to carry out the method according to one of Claims 1 - 5 to execute. Driving assistance system (110) for a vehicle (100), which has a trailer device (140) for coupling a trailer (200) to the vehicle (100), with: a data processing unit (112) for reading out a stored trajectory (TRO), the stored trajectory (TRO) comprising a function of a target articulation angle (HA) as a function of a distance covered (S), the articulation angle (HA) being an angle between a Vehicle longitudinal axis (105) of the vehicle (100) and a trailer longitudinal axis (205) of the coupled trailer (205), a detection unit (114) for detecting an actual articulation angle (HA), which represents the articulation angle (HA) at a current position (P0, P1 - P17, P100) of the vehicle (100) with the coupled trailer (200), and a control unit (116) for causing the vehicle (100) to reverse with the trailer (200) coupled thereto, the control unit (116) being set up to control the vehicle (100) during reverse travel in such a way that the actual articulation angle (HA) as a function of the distance covered (S) is equal to the setpoint articulation angle (HA) corresponding to the distance covered (S). Vehicle (100) with a trailer hitch (140) and with a driver assistance system (110). claim 7 .

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