Method and assistance system for automated speed control of a motor vehicle at roundabouts and correspondingly equipped motor vehicle

Abstract

The invention relates to a method (17) and an assistance system (13) for controlling a motor vehicle (10), as well as to such a motor vehicle (10). In the method (17), when the motor vehicle (10) is detected as approaching a roundabout (1), an entry angle (θ) for the roundabout (1) is determined. Depending on the respective entry angle (θ), a target speed for at least partially automated guidance of the motor vehicle (10) from an access road (2) into the roundabout (1) is then determined, wherein a lower target speed is determined for a steeper entry angle (θ) than for a flatter entry angle (θ). The target speed is then used for the at least partially automated guidance of the motor vehicle (10) from the access road (2) into the roundabout (1).

Description

[0001] The present invention relates to a method and an assistance system for automated speed control of a motor vehicle at roundabouts. The invention further relates to a correspondingly configured motor vehicle.

[0002] Today, efforts are being made to automate vehicle control, for example, for safety and comfort reasons. However, existing automated vehicle control systems do not perform sufficiently comfortably and convincingly for the driver or vehicle occupants in all situations. This can, for example, mean setting the vehicle at a speed that appears inappropriate for curves or roundabouts, or similar situations. Therefore, there is a need for further improvements in this area.

[0003] As one approach, DE 10 2020 107 880 A1, for example, describes a method for controlling the speed of a motor vehicle on a curved roadway. The method records the curve and a planned exit from the curve. The motor vehicle is then accelerated when a change in direction of the motor vehicle from the curve is detected.

[0004] Another approach, US 2017 / 0 057 355 A1, addresses the risk of a vehicle traveling too fast when negotiating a curve. It involves capturing a speed limit and detecting an upcoming curve. The distance from the vehicle's current position to the start position of the curve and the curve's bend radius are then calculated. Based on the bend radius, a maximum speed is calculated at which the vehicle does not deviate from a driving line in the curve. The vehicle's speed is then controlled so that it essentially reaches the calculated maximum speed at the start position of the curve, provided that this does not exceed the speed limit.

[0005] As a further approach, DE 10 2018 207 804 A1 describes a method for dynamically driving through and exiting a roundabout in automatic longitudinal guidance mode. The method includes detecting an exit from the roundabout, providing an acceleration point located before the exit, and accelerating the vehicle to an exit speed upon reaching the acceleration point. This is intended to enable more dynamic and safe driving through and exiting the roundabout.

[0006] The object of the present invention is to enable at least partially automated vehicle guidance at roundabouts that is more pleasant for the driver of a motor vehicle.

[0007] This object is achieved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures. Features, advantages, and possible embodiments presented in the description for one of the subject matter of the independent claims are to be regarded at least analogously as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the subclaims.

[0008] The method according to the invention can be used to control or guide a motor vehicle in an at least partially automated longitudinal guidance mode of the motor vehicle. In this case, the motor vehicle can therefore have, for example, an automatic cruise control system (ACC or pACC) or the like, which carries out the longitudinal guidance or longitudinal control of the motor vehicle. In the method according to the invention, a current or anticipated or imminent approach of the motor vehicle to a roundabout is automatically detected or recognized. Accordingly, corresponding monitoring or checking can be carried out continuously or regularly. For this purpose, for example, the respective current position and / or direction of travel and / or navigation route of the motor vehicle can be evaluated, for example taking into account predetermined map data and / or sensor data from an environmental sensor system or the like.For example, based on the map data and the navigation routes, it could be recognized that the navigation route includes a roundabout. Likewise, for example, the current surroundings of the motor vehicle could be recorded or monitored using a camera and / or other environmental sensors. Based on the corresponding camera or sensor data, the roundabout could then be recognized directly using appropriate image or data processing, or, for example, detected or predicted by recognizing a corresponding sign pointing to the roundabout. Likewise, data received via a Car2X data connection from at least one other vehicle driving ahead of the motor vehicle and / or swarm trajectory data or the like could be used to recognize the upcoming roundabout or the approach to the roundabout.

[0009] If a corresponding approach to a roundabout is detected, an entry or entry angle is automatically determined or calculated for this roundabout. This can be the angle at or below which an access road used for approaching the roundabout meets or flows into the roundabout. For example, an end section of the access road facing the roundabout or leading into the roundabout can be or become represented by a straight access road segment and the roundabout by several straight roundabout segments. An angle lying in the roadway plane between the access road segment and the roundabout segment that the access road segment meets can then be determined or used as the entry angle.Likewise, for example, an angle between the access road segment and a tangent to the roundabout at the junction of the access road with the roundabout or at a predefined location relative thereto, for example in the middle of the access road or at the edge of the access road, can be used as the entry angle.

[0010] Furthermore, in the method according to the invention, a target speed of the motor vehicle is automatically determined as a function of the entry angle for the at least partially automated guidance or control of the motor vehicle from the access road into the roundabout, i.e. for the transition from the access road into the roundabout, i.e., for example, onto the corresponding roundabout segment. This is done in such a way that a lower target speed is determined for a steeper entry angle than for a flatter entry angle. A steeper entry angle, in the present sense, is an entry angle that requires a larger or more pronounced change in direction, i.e., for example, a stronger or greater steering angle of the motor vehicle, in order to change from the access road into the roundabout. A flatter entry angle, on the other hand, accordingly requires a smaller change in direction of the motor vehicle.With a flatter entry angle, the intended directions of travel on the access road or the end section of the access road and in the roundabout at the junction of the access road, for example on the roundabout segment first entered from the access road, are more similar than with a steeper entry angle.

[0011] Furthermore, in the method according to the invention, the determined target speed is then automatically used for the at least partially automated control or guidance of the motor vehicle from the access road into the roundabout. Thus, for example, the determined target speed can be taken into account as a control target for the automated cruise control or longitudinal guidance of the motor vehicle or as an input or an influencing factor in the speed actually used or ultimately used as the control target. For example, the target speed determined based on the entry angle can be adjusted based on current traffic conditions or a predetermined maximum permissible speed or current environmental or road conditions, for example, due to fog or heavy rain, limited visibility, or due to slippery road surfaces caused by snow or ice, or the like.

[0012] For example, it may be provided that the speed of the motor vehicle is automatically controlled or regulated such that the specified target speed or the corresponding control target is met or reached at the end of the access road or at the transition between it and the roundabout. This can apply or be carried out at least or only if the speed of the motor vehicle on the access road before reaching the roundabout is higher than or equal to the specified target speed or the corresponding control target.

[0013] With the present invention, the target speed can be determined individually for each roundabout. For example, different entry or target speeds can result for multiple roundabouts with the same radius. This allows for more situation-appropriate, more comfortable, and generally more human-like automated guidance of the motor vehicle when entering or entering a roundabout. This can be applied, for example, in comparison to previous approaches in which a speed determined solely by taking into account the radio of the roundabout and a predetermined maximum lateral acceleration of the motor vehicle in the roundabout is used as the control target.

[0014] The present invention also relates to an assistance system for at least partially automated speed control of a motor vehicle. The assistance system according to the invention has a data processing device for detecting an approach of the motor vehicle to a roundabout and for determining an entry angle into the roundabout and a target speed for the motor vehicle therefor as a function of the entry angle, or for detecting and processing corresponding data. For this purpose, the data processing device can, for example, have an input interface for detecting or receiving corresponding data. Furthermore, the assistance system according to the invention has an output interface for outputting a control signal for a drive system of the motor vehicle that corresponds to the determined target speed.Such a control signal can, for example, be used to control an actuator of the drive system to set the specific target speed. The assistance system according to the invention is configured to execute the method according to the invention, in particular automatically. For this purpose, the data processing device can comprise, for example, a processing device, such as a microprocessor, microchip, microcontroller, or the like, and a computer-readable data memory coupled thereto. A corresponding operating or computer program can then be stored in this data memory, which encodes or implements the method steps, measures, or sequences, or corresponding control instructions, described in connection with the method according to the invention and / or hereinafter in connection with the assistance system according to the invention and / or the motor vehicle according to the invention.This operating or computer program can then be executable by means of the process device in order to carry out the corresponding method or to cause it to be carried out.

[0015] In one possible embodiment of the present invention, the assistance system is configured to determine the entry angle based on map data for the area of ​​the respective access road and the respective roundabout. For example, the straight-line segments for the access road and the roundabout mentioned elsewhere can be specified or contained in the map data. These segments can also be constructed, for example, based on the map data or inserted into the map data. The entry angle can also be specified directly in the map data. In this case, determining the entry angle can mean or include reading it from the map data by the assistance system. The determination of the entry angle based on the map data proposed here can enable a particularly reliable and consistent determination of the entry angle and thus also of the corresponding target speed.For example, the angle of entry can be determined independently of the respective environmental conditions, such as traffic or weather conditions, and independently of the sensor equipment of the respective motor vehicle.

[0016] In a further possible embodiment of the present invention, the assistance system is configured to monitor the respective current position and / or the respective current or planned trajectory of the motor vehicle on the access road up to the roundabout. Furthermore, the assistance system is then configured to use or take into account, in the event that this at least presumably results in a different entry angle into the roundabout, this for determining the target speed. The different entry angle can therefore be the actual or effective entry angle into the roundabout based on the actual position or trajectory of the motor vehicle. This can, for example, deviate from an entry angle or standard entry angle determined solely on the basis of the directions or road layouts of the access road and the roundabout.This standard entry angle could, for example, arise when the motor vehicle follows exactly a center line of corresponding lanes of the access road and the roundabout or a predefined typical driving line or ideal line.

[0017] A deviation from this and thus a different entry angle can occur, for example, in the event of a change in traffic routing, for example due to an obstacle or construction site or similar, or in the event of a transverse offset of the trajectory or driving line within the lane traveled by the motor vehicle relative to its center line or the like. Such a transverse offset can, for example, be adjusted by an automated longitudinal and lateral guidance system of the motor vehicle in order to optimize distances to a lateral lane boundary and / or to vehicles traveling in an adjacent lane, in particular to oncoming traffic, or in order to avoid a pothole or a slippery area on the access road or roundabout, for example.

[0018] The proposed consideration of the deviating entry angle may, for example, mean that it is used directly or offset or combined in a predefined manner with the entry angle determined independently of the specific position or trajectory of the motor vehicle on the access road, i.e., the standard entry angle. Likewise, it may, for example, be provided that the deviating entry angle is only used or included in the determination of the target speed if its deviation from the standard entry angle is greater than a predefined threshold. The latter can enable more consistent behavior of the motor vehicle in most cases and, in the – presumably rarer – cases of a correspondingly significantly deviating entry angle, still ensure good comfort or situation-appropriate behavior of the motor vehicle.

[0019] The embodiment of the present invention proposed here can overall enable a behavior of the motor vehicle that is even better adapted to the respective actual situation in the individual case and thus an even greater comfort and / or an even greater acceptance of the automated vehicle guidance by the driver or vehicle occupants.

[0020] In a further possible embodiment of the present invention, a maximum lateral acceleration is specified for the motor vehicle. The assistance system is then configured to limit the target speed such that the specified maximum lateral acceleration is not exceeded. In other words, the assistance system can be configured to determine or set the ultimate target speed to a maximum such that the specified maximum lateral acceleration within the roundabout is just reached or at most reached, even if a higher target speed was or would be determined based on the entry angle. This can ensure particularly comfortable and safe behavior of the motor vehicle, for example even in situations - at least currently rather rare - in which the access road meets the roundabout almost tangentially.

[0021] In a possible development of the present invention, the assistance system is configured to determine the target speed based on the specified maximum lateral acceleration and, in doing so, to consider or use an additional multiplicative factor whose value depends at least on the respective entry angle. This additional multiplicative factor can therefore, for example, be included in the standard calculation formula for the speed v = (a r) corresponding to a certain specified lateral acceleration a in a roundabout with radius r. 1 / 2be added. For example, the maximum lateral acceleration can be reduced by multiplying or dividing by the factor. Likewise, for example, the maximum speed for the roundabout resulting from the maximum lateral acceleration according to the formula mentioned can first be calculated and this speed can then be reduced by multiplying or dividing by the factor. There can be various implementation options here, depending, for example, on whether the value of the factor is always at least 1 or at most 1 by definition or according to a corresponding specification. The factor can be unitless and can therefore easily be used for appropriate dynamic scaling of the lateral acceleration or the purely radius- or lateral acceleration-based speed.The approach proposed here for the concrete implementation of the present invention can enable particularly simple and flexible adjustment or adaptation of the behavior of the assistance system or of the motor vehicle guided or controlled by it. To determine the respective value of the factor to be used, for example, a corresponding calculation function or calculation rule, or a characteristic curve or characteristic map, can be specified, in which a dependence of the value of the factor on at least the entry angle is specified or defined. This can, if necessary, be combined with a corresponding interpolation or extrapolation for entry angles or angles not explicitly specified.

[0022] In a possible development of the present invention, the assistance system is configured to use the same predefined value for the factor for all entry angles that are steeper than a predefined upper limit angle, and to use different angle-dependent values ​​for the factor at least for a range of entry angles that are flatter than the predefined upper limit angle. For example, 90° can be specified as the upper limit angle, i.e. a right-angled turn or entry from the access road into the roundabout. At or above this upper limit angle and even larger or steeper entry angles, a factor of 1.3 can always be used to modify or reduce the maximum lateral acceleration or the speed resulting solely from this and the radius of the roundabout. For smaller orFor shallower entrance angles, the angle-dependent value of the factor to be used can be determined, for example, using a characteristic curve or a table and, if necessary, appropriate interpolation. This can be the case or performed for an angle range of the entrance angle from the upper limit angle to a specified lower limit angle, for example, for angles between 90° and 70°.

[0023] Accordingly, in one possible development of the present invention, the assistance system is configured to use the same predefined value or a predefined second fixed value for the factor for all entry angles that are smaller or flatter than a predefined lower limit angle. In this case, too, the assistance system can be configured to use different angle-dependent values ​​for the factor, at least for a certain predefined range of entry angles that are larger or steeper than the predefined lower limit angle. For example, a factor value of 1.1 could be used for an entry angle of 75° and a factor value of 1.05 for an entry angle of 70°. If 70° is specified as the lower limit angle, the factor value of 1.05 can then also be used for all entry angles that are smaller than 70°.

[0024] The proposed use of constant values ​​of the factor, i.e., constant modifications of the maximum lateral acceleration or the resulting speed above and / or below specified limit angles, can enable the avoidance or safe handling of extreme situations particularly simply and effectively. For example, even with unusual traffic routing, excessive or insufficient speeds of the vehicle when entering a roundabout can be avoided with regard to comfort or safety or the driver's expectations.

[0025] In a further possible embodiment of the present invention, the assistance system is configured to also use or predefine the target speed determined for guiding or steering the motor vehicle from the access road into the roundabout as the target speed, i.e., for example, as the control target of the at least partially automated cruise control for the at least partially automated guiding or steering of the motor vehicle for further driving through the roundabout. The determined target speed can therefore be used or predetermine, for example, as the target speed or control target in the roundabout, for example, until an exit maneuver or until leaving the roundabout. The embodiment of the present invention proposed here makes it possible to achieve particularly uniform behavior or speed profile of the motor vehicle in the area of ​​the roundabout.This can benefit comfort and safety. For example, automated braking or acceleration of the vehicle in the roundabout can be avoided or minimized. This can be beneficial for the acceptance of automated vehicle guidance, since human drivers often avoid such speed changes when manually controlling the vehicle while cornering.

[0026] The present invention also relates to a motor vehicle having the assistance system according to the invention and a drive system that can be controlled or regulated by the assistance system. The motor vehicle according to the invention can, in particular, be or correspond to the motor vehicle mentioned in connection with the method according to the invention and / or in connection with the assistance system according to the invention.

[0027] Further features of the invention can be derived from the following description of the figures and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, 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.

[0028] The drawing shows: Fig. 1 is a schematic representation of a first roundabout to illustrate a method for automatically controlling the speed of a motor vehicle at roundabouts; Fig. 2 a schematic representation of a second roundabout to further illustrate the method; Fig. 3 a schematic representation of the motor vehicle equipped for the method; and Fig. 4 an exemplary schematic flow chart for the method.

[0029] Identical or functionally equivalent elements are provided with the same reference numerals in the figures. For the sake of clarity, only a representative selection of identical or similar elements is explicitly marked in the figures, at least in part.

[0030] Fig. 1 shows a schematic overview of a first surrounding area with a roundabout 1 and an access road 2 leading to or merging into it. A portion of the access road 2 shown here can be represented in map data for the surrounding area shown by a straight access road segment 3. Likewise, the roundabout 1 can be represented in this map data by a plurality of straight, interconnected roundabout segments 4. A navigation route for a vehicle approaching the roundabout 1 on the access road 2 would therefore include the access road segment 3 and then an adjoining roundabout segment 4, which is referred to here as the junction segment 5.

[0031] In automated operation of this vehicle, a speed to be used in roundabout 1 could conventionally be determined solely based on a predetermined maximum lateral acceleration to be maintained and the radius of roundabout 1, which can be determined, for example, from the map data. Depending on the implementation, this speed could also be modified by a predetermined fixed factor, for example to achieve a lower and thus more comfortable speed or lateral acceleration and / or, for example, to obtain a larger safety margin against the vehicle swerving in roundabout 1. Such a modification factor is then conventionally constant and identical for all roundabouts 1.

[0032] In reality, however, the driving experience is not identical in all roundabouts 1, or even in all roundabouts 1 with the same radius. Accordingly, instead of the fixed or constant factor, a dynamically determined, i.e., variable factor or factor value is used to determine the target speed for the vehicle entering roundabout 1 or onto junction segment 5 from access road 2. The respective value of this factor is recalculated depending on the respective roundabout 1 being traveled through or the respective individual configuration of the respective roundabout 1 and the respective access road 2.

[0033] For this purpose, the angle at which the access road 2 meets the roundabout 1 or the junction segment 5 can be determined. For this purpose, an access direction 6 extending in a straight line along the access road 2 or along the access road segment 3 is shown schematically here. The roundabout direction 7 is also marked for the junction segment 5. The access direction 6 and the roundabout direction 7 meet at an intersection 8 in the area of ​​the junction of the access road 2 and the roundabout 1. Based on this, an entry angle 9 can then be determined. This entry angle 9 is plotted here on the side of the access direction 6 facing the junction segment 5 and between the section of the access direction 6 lying behind the intersection 8 within the roundabout 1 or in the direction of travel towards the roundabout 1 and the roundabout direction 7. Here, the entry angle 9 is approximately 85°, for example. A larger orA steeper entry angle 9 of more than 90° could mean at least a partial reversal against the direction of travel on the access road 2, i.e. a hairpin bend to enter the roundabout 1. A smaller or flatter entry angle 9, on the other hand, would mean that the roundabout direction 7 would be pivoted around the junction 8 closer to the section of the access direction 6 located in the roundabout 1.

[0034] The factor used to determine the speed used by the corresponding vehicle's automatic cruise control system for entering roundabout 1 or junction segment 5 from access road 2, or the speed targeted as the control target, depends here on the entry angle θ of the respective roundabout 1. Therefore, it is proposed here to replace the previously used fixed and uniform modification factor with a dynamic factor when calculating the correct roundabout entry speed. The value of this factor to be used can depend at least on the entry angle θ but also, for example, on the radius of the respective roundabout 1. If necessary, a corresponding calculation rule, assignment table, characteristic curve, or characteristic map can be specified for this purpose.

[0035] For further illustration, Fig. 2 a schematic representation of a second surrounding area with another roundabout 1 and another access road 2 leading to it. Here, too, the access road 2 is represented in corresponding map data by an access road segment 3 and the roundabout 1 by several circularly arranged, rectilinear roundabout segments 4. Here, too, the given access direction 6 and roundabout direction 7 are indicated to illustrate the determination of the entry angle 9. For the roundabout 1 shown here, the entry angle 9 from the marked access road 2 is approximately 62° and is thus smaller or flatter than that in Fig. 1 marked entry angle 9. Accordingly, for the Fig. 1 and Fig. 2, different entry speeds can be determined even if these roundabouts 1 have the same radius. Likewise, it may be possible that, with different radii of the roundabout 1 and different entry angles 9, their influences on the final entry speed, i.e., the target speed determined for entering or driving into the respective roundabout 1 from the respective access road 2, cancel each other out. In such a special case, the same entry or target speed could possibly be determined for both roundabouts 1 despite their different radii and entry angles 9.

[0036] For further illustration, Fig. 3 shows a schematic representation of a correspondingly configured vehicle, referred to here as a motor vehicle 10. The motor vehicle 10 can, for example, be guided or controlled manually by a driver 11. In particular, however, the motor vehicle 10 is configured here for at least partially automated driving operation, in particular at least partially automated longitudinal guidance or longitudinal control. In this case, for example, a drive system 12, only indicated schematically here, can be automatically controlled or regulated in order to set the aforementioned target speed for or when entering a roundabout 1. For this purpose, the motor vehicle 10 is also equipped here with a corresponding assistance system 13 for determining the respective target speed and for accordingly controlling the drive system 12.For this purpose, the assistance system 13 can, for example, have an interface 14, in particular a bidirectional one, which can be implemented entirely or partially in software and / or hardware. Data can be acquired and control signals output via this interface, for example. To process the acquired data to determine the respective target speed and to generate the corresponding control signal, the assistance system 13 can have a corresponding data processing device or circuit, which is schematically represented here by a processor 15 and a computer-readable data memory 16 connected thereto.

[0037] Fig.4 shows an exemplary schematic flowchart 17 for a corresponding method for controlling the motor vehicle 10. The method can be started in a method step S1. Here, for example, the motor vehicle 10 or the assistance system 13 can be put into operation or the motor vehicle 10 can be put into automated driving mode.

[0038] Subsequently, in a method step S2, a continuous recording of relevant data and, based on this, a monitoring or checking for a current or imminent approach of the motor vehicle 10 to a roundabout 1 can be carried out. Here, for example, position data and / or movement data and / or navigation data that describe or characterize the movement of the motor vehicle 10 can be recorded via the interface 14. Likewise, for example, the aforementioned map data and / or environmental data or sensor data or the like, from which the upcoming roundabout 1 can be determined, can be recorded here. If no current or imminent approach to a roundabout 1 is detected, method step S2 can be repeated, whereby correspondingly updated data can be recorded and processed in each case.

[0039] If an approach to a roundabout 1 is detected, the entry angle 9 for this roundabout 1 can be determined in a subsequent method step S3. Depending on the respective determined entry angle 9, a target speed for the at least partially automated entry of the motor vehicle 10 into the respective roundabout 1 can then be determined in a method step S4.

[0040] In a method step S5, the motor vehicle 10 can then be automatically controlled or guided from the respective access road 2 into the respective roundabout 1, for example using the determined target speed as the control target.

[0041] The approach proposed here, using the dynamic modification factor, i.e., a modification factor determined for each roundabout individually, for the speed resulting solely from the specified maximum lateral acceleration and the roundabout radius, allows the determination of a particularly appropriate roundabout entry speed. This allows the driver 11 to feel safer with appropriate at least partially automated guidance or control of the motor vehicle 10, and overall, interruptions of the at least partially automated vehicle guidance due to manual interventions by drivers 11 can be reduced.

[0042] The procedure described here can be implemented by an approach control system, which is responsible for automated speed control of the motor vehicle 10 during an approach phase, i.e., when the motor vehicle 10 approaches the roundabout 1 until it reaches it. A corresponding roundabout control system can then be provided for the automated guidance or speed control of the motor vehicle 10 within the respective roundabout 1. These various controls can be adopted or implemented by different controllers. Likewise, a common or combined controller can be used for both phases, i.e., the approach to the respective roundabout 1 on the one hand and the passage through the respective roundabout 1 on the other.

[0043] Overall, the described examples show how a dynamic factorization of the roundabout entry speed can be implemented and applied, for example when using a predictive or anticipatory cruise control system (pACC). List of reference symbols 1 roundabout 2 access road 3 access road segment 4 roundabout segments 5 Junction segment 6 Access direction 7 roundabout direction 8 Junction 9 Entry angle 10 motor vehicle 11 drivers 12 Drive system 13 Assistance system 14 Interface 15 processor 16 data storage 17 Schedule S1-S5 process steps QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 107 880 A1

[0003] US 2017 / 0 057 355 A1

[0004] DE 10 2018 207 804 A1

[0005]

Claims

[1] Method (17) for controlling a motor vehicle (10) with at least partially automated longitudinal guidance of the motor vehicle (10), wherein automatically - an approach of the motor vehicle (10) to a roundabout (1) is detected, - an entry angle (9) at which an access road (2) used for approaching the roundabout (1) meets the roundabout (1) is determined, - a target speed for the at least partially automated guidance of the motor vehicle (10) from the access road (2) into the roundabout (1) is determined as a function of the entry angle (9), wherein a lower target speed is determined for a steeper entry angle (9) than for a flatter entry angle (9), and - the target speed is used for at least partially automated guidance of the motor vehicle (10) from the access road (2) into the roundabout (1). [2] Assistance system (13) for at least partially automated speed control of a motor vehicle (10), comprising a data processing device (14, 15, 16) for detecting an approach of the motor vehicle (10) to a roundabout (1) and for determining an entry angle (9) into the roundabout (1) and a target speed for the motor vehicle (10) therefor as a function of the entry angle (9), and an output interface (14) for outputting a control signal corresponding to the determined target speed for a drive system (12) of the motor vehicle (10), wherein the assistance system (13) is configured to carry out the method (17) according to claim 1. [3] Assistance system (13) according to claim 2, characterized by that the assistance system (13) is designed to determine the entry angle (9) based on map data (3, 4) for the area of ​​the access road (2) and the roundabout (1). [4] Assistance system (13) according to claim 2 or 3, characterized by that the assistance system (13) is designed to monitor the position and / or trajectory of the motor vehicle (10) on the access road (2) up to the roundabout (1) and, if this results in a different entry angle (9) into the roundabout (1), to take this into account for determining the target speed. [5] Assistance system (13) according to one of claims 2 to 4, characterized by that a maximum lateral acceleration is specified for the motor vehicle (10) and the assistance system (13) is designed to limit the target speed in such a way that the specified maximum lateral acceleration is not exceeded. [6] Assistance system (13) according to claim 5, characterized bythat the assistance system (13) is designed to determine the target speed based on the predetermined maximum lateral acceleration and to use an additional multiplicative factor, the respective value of which depends at least on the respective entry angle (9). [7] Assistance system (13) according to claim 6, characterized by that the assistance system (13) is configured to use the same predetermined value for the factor for all entry angles (9) that are steeper than a predetermined upper limit angle and to use different angle-dependent values ​​for the factor for at least a range of entry angles (9) that are flatter than the predetermined upper limit angle. [8] Assistance system (13) according to claim 6 or 7, characterized bythat the assistance system (13) is configured to use the same predetermined value for the factor for all entry angles (9) that are flatter than a predetermined lower limit angle and to use different angle-dependent values ​​for the factor for at least a range of entry angles (9) that are steeper than the predetermined lower limit angle. [9] Assistance system (13) according to one of claims 2 to 8, characterized by that the assistance system (13) is designed to use the target speed determined for driving the motor vehicle (10) from the access road (2) into the roundabout (1) also as the target speed for the at least partially automated driving of the motor vehicle (10) for further driving through the roundabout (1). [10] Motor vehicle (10), comprising an assistance system (13) according to one of claims 2 to 9 and a drive system (12) controllable by the assistance system.

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