DE102018131898A1 - Method for determining a trajectory by applying Bézier curves tangentially to geometric structures; Control unit; Driver assistance system; Computer program product and computer readable medium - Google Patents

Abstract

The invention relates to a method for determining a trajectory (5) for controlling a motor vehicle (1) during a driving maneuver in a surrounding area (U) of the motor vehicle (1). The following steps are provided to enable a more resource-saving calculation of the trajectory (5): - determining a limit (8) for a possible driving corridor of the motor vehicle (1) in a virtual maneuvering space (16), - determining a starting position (11) and an end position (12) for the motor vehicle (1) in relation to the driving maneuver in the virtual maneuvering space (16), - arranging a predetermined geometric structure (9) in a predetermined relative position with respect to the boundary (8) in the virtual maneuvering space ( 16), - determining a tangent (10) for the geometric structure (9), - connecting a point of contact (17) of the tangent (10) both with the start position (11) and the end position (12) with a respective Bezier curve (6 , 7), the respective Bezier curves (6, 7) in the contact point (17) parallel to the tangent (10) together forming the trajectory (5).

Description

The invention relates to a method for determining a trajectory for controlling a motor vehicle during a driving maneuver in a surrounding area of the motor vehicle. The invention also relates to a control unit for determining a trajectory and a driver assistance system for controlling a motor vehicle. Further aspects of the invention relate to a computer program product and a computer-readable medium.

To control a motor vehicle, in particular for autonomously controlling a motor vehicle, it is known to first determine a trajectory for a future journey or a future driving maneuver of the motor vehicle. In particular, the path along which the motor vehicle is to be moved from a start position to an end position is provided in the form of the trajectory. For example, the trajectory is determined or calculated as a function of the start position, the end position and limits in the area surrounding the motor vehicle. Examples of restrictions are other road users, for example third-party vehicles, cyclists and pedestrians, parked vehicles, lane boundaries, curbs and / or any foreign objects. The driving maneuver can be a parking maneuver, for example.

The determination of a trajectory in the form of a Bezier curve is, for example, from the EP 2 091 803 B1 as well as from the US 2010/00 85 170 A1 known. In many cases, however, it is not possible to find a simple Bezier curve from the start position to the end position. In this case it is necessary to link two or more Bezier curves. These multiple Bezier curves can each be referred to as Bezier segments.

It is an object of the present invention to enable a resource-saving calculation of a trajectory on the basis of several Bezier curves.

This object is achieved according to the invention by the subject matter of the independent claims. Advantageous embodiments and expedient further developments are the subject of the subclaims.

• - Bestimmen einer Begrenzung für einen möglichen Fahrkorridor des Kraftfahrzeugs in einem virtuellen Manöverraum,
• - Bestimmen einer Startposition sowie einer Endposition für das Kraftfahrzeug in Bezug auf das Fahrmanöver in dem virtuellen Manöverraum,
• - Anordnen einer vorgegebenen geometrischen Struktur in einer vorbestimmten Relativposition in Bezug auf die Begrenzung in dem virtuellen Manöverraum,
• - Bestimmen einer Tangente für die geometrische Struktur,
• - Verbinden eines Berührpunkts der Tangente sowohl mit der Startposition als auch der Endposition mit einer jeweiligen Bezierkurve, wobei die jeweiligen Bezierkurven in dem Berührpunkt beide parallel zu der Tangente verlaufen und die jeweiligen Bezierkurven gemeinsam die Trajektorie bilden.

A first aspect of the invention relates to a method for determining a trajectory for controlling a motor vehicle during a driving maneuver, in particular a parking maneuver, in a surrounding area of the motor vehicle with the following steps:

• Determining a limit for a possible driving corridor of the motor vehicle in a virtual maneuvering space,
• Determining a start position and an end position for the motor vehicle in relation to the driving maneuver in the virtual maneuvering space,
• Arranging a predetermined geometric structure in a predetermined relative position with respect to the boundary in the virtual maneuvering space,
• - determining a tangent for the geometric structure,
• - Connecting a point of contact of the tangent with both the start position and the end position with a respective Bezier curve, the respective Bezier curves in the point of contact both running parallel to the tangent and the respective Bezier curves together forming the trajectory.

The possible driving corridor can be modeled, for example, on an area of the surrounding area which is covered by the motor vehicle during the driving maneuver. In addition, the possible driving corridor can be larger by a predetermined safety distance than the area of the surrounding area covered by the motor vehicle. The possible driving corridor can thus be used to determine in which subareas of the surroundings movement of the motor vehicle is possible at all. For example, subareas of the surrounding area are determined which are not accessible to the motor vehicle due to the limitation. Of course, more than one limitation, in particular a large number of limitations, can also be determined in the virtual maneuvering space.

The starting position of the motor vehicle can correspond to a position of the motor vehicle at the start of the driving maneuver. For example, the motor vehicle is in the starting position while the trajectory is being determined. In this case, the current position of the motor vehicle can be determined as the starting position. Alternatively, a position can be determined as the starting position in which the motor vehicle will be located at a later point in time.

The end position can be a target position for the motor vehicle at the end of the driving maneuver. For example, the end position is a desired position for the motor vehicle into which the motor vehicle is to be steered during the driving maneuver. If the driving maneuver is a parking maneuver, the end position can be one Parking position in a previously selected parking lot or parking space.

The virtual maneuvering room can be a map of the surrounding area. For example, a digital map of the surrounding area is generated. The limitation, the start position and / or the end position for later processing can be entered in this map. Alternatively, the virtual maneuvering space can be a geometric model of the surrounding area.

The given geometric structure can be a primitive geometric structure. For example, the given geometric structure is a basic geometric structure. Examples of such basic structures are circles and / or straight lines. The predefined geometric structure can be arranged in the predetermined relative position relative to the boundary in the virtual maneuvering space. In addition, one or more parameters for the geometric structure can be specified. In the case of a circle, such a parameter can be, for example, the radius or the length of an arc. In the case of a straight line, the parameter can determine the length of the straight line.

Then the tangent is created on the geometric structure. The tangent has a common point of contact with the geometric structure. At the point of contact, the tangent runs parallel to the geometric structure.

The tangent can now be used as a construction aid for determining respective Bezier curves. In particular, it is provided that a respective Bezier curve is drawn from the point of contact to the start position and to the end position. In other words, a first Bezier curve which connects the point of contact with the start position is determined, and a second Bezier curve which connects the point of contact with the end position is determined. The first and the second Bezier curve at the point of contact are both aligned parallel to the tangent. In other words, the two Bezier curves meet at the point of contact of the tangent with the given geometric structure. The two Bezier curves at the point of contact each run parallel to the tangent.

The problem of determining a multi-part trajectory, which is composed of several Bezier curves, can be significantly simplified by the geometric structure. The geometric structure, or by the tangent and its point of contact, provides secondary conditions that make it easier to determine the individual Bezier curves. In this way, the trajectory can be determined in a particularly resource-saving manner.

The present method can also be carried out several times on the basis of different predefined geometric structures. In other words, different geometric structures are arranged in the virtual maneuver space in different runs of the above-mentioned method steps, a corresponding respective tangent is determined for this and at least two Bezier curves are determined on the basis of the tangent and its point of contact. The trajectory can then be determined on the basis of the geometric structure, which is most suitable according to a predetermined criterion. For example, the different geometric structures with different parameters can be arranged in the virtual maneuvering space. For example, the different geometric structures are arcs of different lengths and / or different radius. In this case, respective contact points of the respective tangents of the different arcs can be connected to the start position and the end position by means of a respective Bezier curve. A respective candidate for the trajectory can then be determined based on the respective geometric structure. The most suitable trajectory is then determined from the candidates as part of a selection process. Criteria for this can be, for example, the curvature and the distance of the respective candidate for the trajectory from the boundary. The curvature of the trajectory determines the steering angle when the trajectory is driven down. In this way, a particularly suitable trajectory can be determined in a resource-saving manner.

According to a further development, it is provided that for the determination of the tangent, several potential tangents are applied to the geometric structure and one of the potential tangents is selected as the tangent. For example, several potential tangents are determined in such a way that they touch the geometric structure at a predetermined distance from one another. Alternatively or additionally, it can be provided that the potential tangents are determined in such a way that they differ by a maximum of a predetermined angle. This ensures that the potential tangents are placed at a reasonable distance from each other on the geometric structure. Finally one of the several potential tangents is selected as the tangent. This can be done, for example, by connecting respective contact points of the potential tangents with the start position and the end position. For unsuitable This attempt to connect may fail tangents. Specifically, attempts can be made to connect each of the respective points of contact of the several potential tangents with a respective first Bezier curve with the start position and with a respective second Bezier curve with the end position. Then that potential tangent is selected for which the most advantageous course of the respective Bezier curves results according to a predetermined criterion. The criteria can be used to select the above-mentioned criteria, i.e. curvature and / or distance from the boundary. The use of several potential tangents increases the resource consumption a bit, but an improved trajectory can still be determined in this way.

According to a further development, it is provided that the driving maneuver is a parking maneuver and a corner of a parking space is determined as the boundary. In other words, it is provided that the motor vehicle is parked in the parking lot or parking space during the driving maneuver. This is done especially autonomously. For example, the parking lot or parking space can be limited to two or three of its sides by respective lane markings. In particular, parking takes place via a free side of the parking lot. In particular, the corner, which is determined as the boundary, borders on the free side of the parking lot. The parking maneuver can be done in reverse. In other words, it can be provided that the motor vehicle is steered backwards along the trajectory from the start position into the end position during the parking maneuver.

According to a further development, it is provided that a circular arc with a predetermined radius is arranged around the boundary as the geometric structure. In other words, an arc of a predetermined radius is aligned as the geometric structure on the boundary. A point of the boundary can form a center point of the circular arc. The predetermined radius can depend in particular on the space requirement of the motor vehicle during the driving maneuver. In particular, the predetermined radius corresponds to at least one width of the motor vehicle plus a predetermined value for the safety distance. In this way, the geometric structure can be used to ensure that a suitable trajectory is determined which is collision-free with respect to the boundary.

In particular, the circular arc with a predetermined radius is arranged around the corner of the parking lot if the driving maneuver is a parking maneuver. In this way it can be ensured that the trajectory for parking can be determined particularly advantageously.

• - eine weitere vorgegebene geometrische Struktur in einer vorbestimmten Relativposition in Bezug auf die Endposition in dem virtuellen Manöverraum angeordnet wird, ein Stützpunkt für diese weitere geometrischen Struktur bestimmt wird, und die jeweilige Bezierkurve von der Endposition zum Berührpunkt der Tangente der geometrischen Struktur derart bestimmt wird, dass die entsprechende Bezierkurve in dem Stützpunkt der weiteren geometrischen Struktur parallel zur der weiteren geometrischen Struktur verläuft.

According to a further development, it is provided that

• a further predetermined geometric structure is arranged in a predetermined relative position with respect to the end position in the virtual maneuvering space, a base point is determined for this further geometric structure, and the respective Bezier curve is determined from the end position to the point of contact of the tangent to the geometric structure, that the corresponding Bezier curve in the base of the further geometrical structure runs parallel to the further geometrical structure.

In other words, the first Bezier curve, ie the respective Bezier curve, runs from the end position to the point of contact of the tangent of the geometric structure of the boundary, from the base point of the further geometric structure to the point of contact of the geometric structure. The corresponding (first) Bezier curve at the point of contact is parallel to the respective tangent. In the base, the corresponding (first) Bezier curve runs parallel to the other geometric structure. The further predetermined geometric structure can be, for example, an arc and / or a straight line. In the case of an arc, another tangent can be determined through the base. The further tangent for the further geometric structure can be determined in an analogous manner to the tangent for the geometric structure. In particular, the further tangent can be selected for the further geometric structure based on several potential tangents. In this case, the corresponding (first) Bezier curve in the base point runs parallel to the further tangent. The further geometric structure can ensure in a particularly advantageous manner that the motor vehicle assumes a desired orientation with respect to the end position at the end of the driving maneuver.

• - eine weitere vorgegebene geometrische Struktur in einer vorbestimmten Relativposition in Bezug auf die Startposition in dem virtuellen Manöverraum angeordnet wird,
• - ein Stützpunkt für diese weitere geometrischen Struktur bestimmt wird, und
• - die jeweilige Bezierkurve von der Startposition zum Berührpunkt der Tangente der geometrischen Struktur der Begrenzung derart bestimmt wird, dass die entsprechende Bezierkurve in dem Stützpunkt der weiteren geometrischen Struktur parallel zur der weiteren geometrischen Struktur verläuft.

Alternatively or additionally, it is provided that

• a further predetermined geometric structure is arranged in a predetermined relative position with respect to the starting position in the virtual maneuvering space,
• - a base for this further geometric structure is determined, and
• - The respective Bezier curve from the starting position to the point of contact of the tangent to the geometric structure of the boundary it is determined that the corresponding Bezier curve in the base of the further geometric structure runs parallel to the further geometric structure.

In other words, the second Bezier curve, that is to say the respective Bezier curve, runs from the starting position to the contact point of the tangent of the geometric structure of the boundary, from the base point of the further geometric structure to the contact point of the geometric structure. The corresponding (second) Bezier curve at the point of contact is parallel to the respective tangent. At the base, the corresponding (second) Bezier curve runs parallel to the other geometric structure. The further predetermined geometric structure can be, for example, an arc and / or a straight line. In the case of an arc, another tangent can be determined through the base. The further tangent for the further geometric structure can be determined in an analogous manner to the tangent for the geometric structure. In particular, the further tangent can be selected for the further geometric structure based on several potential tangents. In this case, the corresponding (second) Bezier curve in the base point runs parallel to the further tangent. The further geometric structure can ensure in a particularly advantageous manner that the motor vehicle assumes a desired orientation with respect to the end position at the end of the driving maneuver.

In other words, the first Bezier curve, that is to say the Bezier curve from the starting position to the point of contact of the tangent of the geometric structure of the boundary, can be determined such that it runs through the point of contact of the further geometric structure and through the point of contact of the geometric structure. The first Bezier curve is parallel to the respective tangent of the respective contact point, in particular in both contact points. In this way, an orientation of the motor vehicle in the starting position can be taken into account when planning the trajectory.

Both of the above-mentioned further developments can of course also be combined with one another. In other words, respective further predefined geometric structures can be determined both for the start position and for the end position. In this case, a particularly well-suited tangent for the driving maneuver can be determined.

According to a further development, it is provided that a steering angle of the motor vehicle is determined and an arc, the curvature of which is derived from the steering angle, is arranged as the further geometric structure for the starting position in the virtual maneuvering space.

In other words, the geometrical structure allows the current steering angle of the motor vehicle to be taken into account in the starting position.

According to a further development, it is provided that a respective straight line is arranged in the virtual maneuvering space as the further geometric structure for the start position and / or the end position. If the above-mentioned circular arc is arranged as the further geometric structure for the start position in the virtual maneuver space, the straight line can of course optionally be arranged only for the end position in the virtual maneuver space. In the case of a straight line as a further geometric structure, the tangent is of course not a tangent in the geometric sense. Nevertheless, one or more support points can be arranged on the further geometric structure in an analogous manner. At these interpolation points, which are to be understood analogously to the points of contact of the tangent, the respective Bezier curve can be connected to the point of contact of the geometric structure of the boundary. The respective Bezier curve in the corresponding base runs parallel to the straight line. With the respective straight line, the trajectory can be adapted even more precisely to the driving maneuver.

According to a development, it is provided that the trajectory is only checked for its passability, in particular for a maximum steering angle of the motor vehicle or for its freedom from collisions, after the trajectory has been determined. In particular, the tangent is first determined on the basis of the respective Bezier curves, and only then is it checked, for example as part of a simulation of a journey along the trajectory, whether the trajectory is collision-free and / or does not exceed the maximum steering angle of the motor vehicle. The driveability is considered, for example, when the trajectory can be driven by the motor vehicle without a collision and its maximum steering angle is not exceeded. Only if the trajectory is passable can it subsequently be used to control the driving maneuver, in particular autonomously. The fact that neglectability is neglected while determining the trajectory makes it possible to determine the trajectory in a particularly resource-saving manner. The given geometrical structures in turn are passable with a high degree of probability.

According to a further development, it is provided that a limit point is determined, up to which the trajectory can be driven, and one Connection trajectory is determined by performing the above-described steps again, the limit point forming the starting position for the connection trajectory.

In other words, the previously determined trajectory is not completely rejected if it is not completely passable. On the contrary, it is envisaged that the trajectory will be driven up to the limit point. The connection trajectory is then determined from the limit point as the new starting position in an analogous manner to the previous trajectory. In this way, a computing time required to calculate an overall trajectory, which is composed of the trajectory up to the limit point and the connecting trajectory, can be reduced, since the trajectory is used at least in part. A complete recalculation can thus be dispensed with.

According to a further development, it is provided that a direction of travel of the motor vehicle for the connecting trajectory is chosen to be the reverse of the previous trajectory. In other words, it is advantageously provided that the motor vehicle changes the direction of travel at the limit point. For example, the motor vehicle travels backwards (forwards) on the trajectory. In this case, the connection trajectory can then be traveled forward (backward). This allows a maneuver to be initiated. This improves the agility of the motor vehicle on the trajectory or the connecting trajectory.

A second aspect of the invention relates to a control unit for determining a trajectory for controlling a motor vehicle during a driving maneuver in a surrounding area of the motor vehicle with a computing unit which is designed to carry out the method according to the invention for determining a trajectory.

For this purpose, the control unit can additionally have an input part, by means of which the control unit is set up to receive an image and / or a digital map of the surrounding area. For example, the input part has an interface to a sensor device, for example a camera system, a radar system or a lidar system, of the motor vehicle.

A third aspect of the invention relates to a driver assistance system for controlling a motor vehicle during a driving maneuver in a surrounding area of the motor vehicle with the above-mentioned control unit. In addition, the driver assistance system can have the above-mentioned sensor device. In addition, the driver assistance system can optionally have a further control unit for controlling a movement of the motor vehicle. The further control unit can be designed, for example, to control a steering system, brakes and / or an engine of the motor vehicle. The engine can be, for example, an internal combustion engine or an electric motor.

The invention also includes a motor vehicle with the driver assistance system mentioned above. The motor vehicle can include the named engine. For example, the motor vehicle is a motor vehicle, in particular a passenger car or a truck. Depending on the type of engine mentioned, the motor vehicle can be an internal combustion engine, an electric vehicle or a hybrid vehicle.

Another aspect of the invention relates to a computer program product with program code means which are stored in a computer-readable medium in order to carry out the method according to the invention for determining a trajectory when the computer program product is processed on a processor of an electronic control unit. The computer program product according to the invention thus implements the method according to the invention.

The invention also includes a computer-readable medium, in particular in the form of a computer-readable floppy disk, CD, DVD, memory card, USB storage device or the like, in which program code means are stored in order to carry out the method for determining a trajectory when the program code means are stored in a memory electronic control unit loaded and processed on a process of the electronic control unit.

Further features of the invention result from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description and 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 combination indicated in each case, but also in other combinations without departing from the scope of the invention . Embodiments of the invention are thus also to be regarded as encompassed and disclosed, which are not explicitly shown and explained in the figures, but which emerge from the explanations explained and can be generated by separate combinations of features. Designs and combinations of features are also to be regarded as disclosed, which therefore do not have all the features of an originally formulated independent claim. There are also designs and Combinations of features, in particular those explained above, are to be regarded as disclosed which go beyond or differ from the combinations of features set out in the references of the claims.

• 1 in einer schematischen Vogelperspektive ein Kraftfahrzeug;
• 2 ein beispielhaftes Ablaufdiagramm einer Ausführungsform eines Verfahrens zum Bestimmen einer Trajektorie zum Steuern des Kraftfahrzeugs; sowie
• 3 bis 6 jeweils in einer schematischen Vogelperspektive das Bestimmen einer Trajektorie in einem Umgebungsbereich des Kraftfahrzeugs.

Show:

• 1 a schematic bird's eye view of a motor vehicle;
• 2nd an exemplary flow chart of an embodiment of a method for determining a trajectory for controlling the motor vehicle; such as
• 3rd to 6 in each case in a schematic bird's eye view, the determination of a trajectory in a surrounding area of the motor vehicle.

1 shows a motor vehicle 1 with a driver assistance system 4th for autonomous control of the motor vehicle 1 . The driver assistance system 4th enables the control of the motor vehicle during a driving maneuver in a surrounding area U of the motor vehicle 1 . In particular, the driving maneuver is a parking maneuver. The driver assistance system indicates this 4th a control unit 2nd to determine a trajectory 5 on. The driver assistance system also includes 4th another control unit 3rd for autonomous control of the driving maneuver, in particular the parking maneuver, according to the trajectory 5 . For example, the other control unit 3rd set up a steering function 25th , a braking function 26 or an engine 27th of the motor vehicle 1 head for. In other words, the other control unit 3rd for controlling driving functions of the motor vehicle 1 set up. To determine the trajectory 5 can the control unit 2nd a virtual map and / or an image of the surrounding area U from a sensor device of the motor vehicle 1 receive. For example, the sensor device can be cameras 21st and / or ultrasonic sensors 22 include.

2nd shows an exemplary flow chart of a method for determining the trajectory 5 to control the motor vehicle 1 . In one step S1 becomes a limitation 8th for a possible driving corridor of the motor vehicle 1 in a virtual maneuvering room 16 certainly. In one step S2 becomes a starting position 11 as well as an end position 12 for the motor vehicle 1 in relation to the driving maneuver in the virtual maneuvering room 16 certainly. In one step S3 becomes a given geometric structure 9 in a predetermined relative position with respect to a boundary 8th in the virtual maneuvering room 16 arranged. In one step S5 becomes a tangent 10th for the geometric structure 9 certainly. In the present embodiment, the step S4 a variety of tangents 10th to the geometric structure 9 and one of the many tangents 10th selected. Finally, one step S5 a touch point 17th the selected tangent 10th both with the starting position 11 as well as with the end position 12 with a Bezier curve 6 , 7 connected. The respective Bezier curves run here 6 , 7 in the touch point 17th both parallel to the corresponding tangent 10th . Together, the two Bezier curves form 6 , 7 the trajectory 5 .

These steps are followed by the 3rd and 4th illustrated. In the present example, the driving maneuver is a parking maneuver. The motor vehicle 1 to a parking lot or parking space 19th parked. The arrow direction of the arrow representing the starting position 11 or the end position 12 visualized, gives the orientation of the motor vehicle 1 on. Accordingly, this is a rear-facing parking maneuver. The limitation 8th is in the corner of the parking lot 19th . The corresponding corner is directly adjacent to one side of the parking lot 19th , about which the motor vehicle 11 to the parking lot 19th is controlled.

To the limit 8th , the corner of the parking lot 19th , is called the geometric structure 9 arranged an arc with a predetermined radius. The predetermined radius of the circular arc corresponds to at least one width of the motor vehicle 1 plus a security surcharge. This ensures that the motor vehicle 1 the limitation 8th along the geometric structure 9 theoretically or with a high probability could drive around. This will most likely become a trajectory 5 determines which by the motor vehicle 1 is actually passable. As will be explained in the following, however, the passability is checked in a final step. Then go for the geometric structure 9 several tangents 10th certainly. One of the tangents 10th or their base 17th is used as a base for the trajectory 5 selected. Also more on this below.

Another geometric structure 13 is in a predetermined relative position with respect to the end position 12 arranged. This is the other geometric structure 13 around a straight line. On the other geometric structure 13 become several bases 14 arranged. Analogous to the tangents 10th is through the bases 14 additionally a course of the geometric structure 13 in the corresponding base 14 specified. Also from these bases 14 becomes a single one for determining the trajectory 5 selected.

Via a first Bezier curve 6 become the point of contact 17th and the starting point 11 together connected. Via a second Bezier curve 7 become the selected one of the bases 14 and the touch points 17th connected with each other. Through the two Bezier curves 6 , 7 is the overall trajectory 5 provided. Selecting one of the tangents 10th and / or one of the bases 14 can be done, for example, for all possible combinations of tangents 10th as well as touch points 17th a respective second Bezier curve 7 as well as a respective first Bezier curve 6 is determined. In the present example there are four potential tangents 10th as well as three potential bases 14 . In the present example, it is therefore necessary to have four different first Bezier curves 6 for each of the potential tangents 10th to determine. Similarly, it is necessary to have twelve different second Bezier curves 7 for the different possible combinations of potential tangents 10th and bases 14 to determine. Because both the first Bezier curve 6 , as well as the second Bezier curve 7 in the touch point 17th parallel to the selected one of the tangents 10th is a further coordination of the two Bezier curves 6 , 7 not necessary. Finally, you can choose from the possible candidates for the two Bezier curves 6 , 7 the most suitable are selected. The suitability can be checked, for example, on the basis of predetermined criteria. The criteria can be a curve of the curvature which is as uniform as possible and / or a distance from the boundaries which is as large as possible 8th be. In this way, the trajectory 5 be determined.

Optionally, multiple candidates for the trajectory 5 be determined, with the geometric structure for each of the candidates 9 in another predetermined relative position with respect to the limitation 8th in the virtual maneuvering room 16 is arranged. For example, the circular arc, which in the present example is the geometric structure 9 forms, in different radius around the boundary 8th , the corner of the parking lot 19th , arranged around. Then multiple trajectories 5 with the radius of the arc as a parameter. This in turn can be the most suitable trajectory according to the criteria mentioned 5 to be selected.

Then the trajectory 5 checked for their passability. In particular, it is checked whether the trajectory 5 collision-free by the motor vehicle 1 can be driven and whether a maximum steering angle of the motor vehicle 1 is exceeded. In the example of 5 is in a border point 15 the maximum steering angle of the motor vehicle 1 exceeded. Hence the trajectory 5 only to the limit point 15 passable.

In 6 it is found that the trajectory 5 only to the limit point 15 is collision-free. Would the motor vehicle 1 the trajectory 5 further than the limit point 15 would follow, would be a collision with a boundary of the parking lot 19th the consequence.

To save further computing capacity, the trajectory 5 in the examples of 5 and 6 not completely rejected. Instead, a respective follow-up trajectory with the limit point 15 determined as the starting position. In other words, the connecting trajectory closes 18th at the border point 15 to the trajectory 5 on. The connection trajectory 18th especially with the same steps ( S1 to S5 ) are determined like the trajectory 5 . In the example according to 5 keeps the motor vehicle 1 at the transition to the connecting trajectory 18th the direction of travel as with the trajectory 5 at. In the example according to 6 becomes the connecting trajectory 18th with the opposite direction of travel compared to the trajectory 5 drive on. Thus, the example is according to 6 a maneuver.

By using the bases 14 as well as the tangents 10th or the point of contact 17th the calculation of the trajectory 5 or the Bezier curves 6 , 7 is supported, a computing time necessary for this can be reduced. Also when trying out different possibilities for the relative position of the geometric structure 9 and / or different trajectories 10th and / or bases 14 , the number of different possibilities can be reduced to a comparatively low level. While calculating the trajectory 5 there is also no need to check the passability, thanks to the geometric structure 9 the ability to drive is guaranteed with high probability. Should be a final check of the navigability after determining the trajectory 5 point out the trajectory 5 a connection trajectory can only be partially driven on with minimal computing effort 18th be determined which to the trajectory 5 at the border point 15 connects.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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

• EP 2091803 B1 [0003]
• US 2010/0085170 A1 [0003]

Claims (15)

Method for determining a trajectory (5) for controlling a motor vehicle (1) during a driving maneuver in a surrounding area (U) of the motor vehicle (1), with the steps: - determining a limit (8) for a possible driving corridor of the motor vehicle (1) in a virtual maneuvering space (16), - determining a start position (11) and an end position (12) for the motor vehicle (1) in relation to the driving maneuver in the virtual maneuvering space (16), - arranging a predetermined geometric structure (9) in a predetermined relative position with respect to the boundary (8) in the virtual maneuvering space (16), Determining a tangent (10) for the geometric structure (9), - Connecting a contact point (17) of the tangent (10) both with the start position (11) and the end position (12) with a respective Bezier curve (6, 7), the respective Bezier curves (6, 7) in the contact point (17 ) both run parallel to the tangent (10) and the respective Bezier curves (6, 7) together form the trajectory (5). Procedure according to Claim 1 , characterized in that for determining the tangent (10) several potential tangents (10) are applied to the geometric structure (9) and one of the potential tangents (10) is selected as the tangent (10). Method according to one of the preceding claims, characterized in that the driving maneuver is a parking maneuver and a corner of a parking lot (19) is determined as the boundary (8). Method according to one of the preceding claims, characterized in that a circular arc with a predetermined radius around the boundary (8) is arranged as the geometric structure (9). Method according to one of the preceding claims, characterized in that - a further predetermined geometric structure (13) is arranged in a predetermined relative position with respect to the end position (12) in the virtual maneuvering space (16), - a base (14) for this further geometric structure (13) is determined, and - the respective Bezier curve (7) from the end position to the contact point (17) of the tangent (10) of the geometric structure (9) is determined in such a way that the corresponding Bezier curve (7) in the base point (14) of the further geometric structure (13) runs parallel to the further geometric structure (13). Method according to one of the preceding claims, characterized in that - a further predetermined geometric structure (13) is arranged in a predetermined relative position with respect to the starting position (11) in the virtual maneuvering space (16), - a base for this further geometric structure is determined, and - the respective Bezier curve (6) from the starting position to the point of contact of the tangent (10) of the geometric structure (9) of the boundary is determined in such a way that the corresponding Bezier curve (6) in the base point (14) of the further geometric structure runs parallel to the other geometric structure. Procedure according to Claim 6 , characterized in that - a steering angle of the motor vehicle (1) is determined, and - an arc, the curvature of which is derived from the steering angle, as the further geometric structure (13) for the starting position (11) in the virtual maneuvering space (16) is arranged. Procedure according to one of the Claims 5 to 7 , characterized in that a respective straight line is arranged as the further geometric structure (13) for the start position (11) and / or the end position (12) in the virtual maneuvering space (16). Method according to one of the preceding claims, characterized in that the trajectory (5) is only checked for driveability after it has been determined, in particular with regard to a maximum steering angle of the motor vehicle (1) or for its freedom from collisions. Procedure according to Claim 9 , characterized in that - a limit point (15) is determined up to which the trajectory (5) can be driven, and - a connecting trajectory (18) by carrying out the steps of Claim 1 is determined, the limit point (15) forming the starting position for the connecting trajectory (18). Procedure according to Claim 10 , characterized in that a direction of travel of the motor vehicle (1) for the connecting trajectory (18) is selected in reverse to the previous trajectory (5). Control unit (2) for determining a trajectory (5) for controlling a motor vehicle (1) during a driving maneuver in a surrounding area (U) of the motor vehicle (1) with a computing unit which is designed to carry out a method according to perform one of the preceding claims. Driver assistance system (4) for controlling a motor vehicle (1) during a driving maneuver in a surrounding area (U) of the motor vehicle (1) with a control unit (2) Claim 12 . Computer program product with program code means, which are stored in a computer-readable medium, for the method for determining a trajectory (5) according to one of the preceding Claims 1 to 11 to be carried out when the computer program product is processed on a processor of an electronic control unit (2). Computer-readable medium, in particular in the form of a computer-readable floppy disk, CD, DVD, memory card, USB memory unit, or the like, in which program code means are stored in order to determine the method for determining a trajectory (5) according to one of the preceding Claims 1 to 11 to be carried out when the program code means are loaded into a memory of an electronic control unit (2) and processed on a processor of the electronic control unit (2).

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