Method and system for longitudinal control of a motor vehicle

Abstract

According to a method for at least partially automatic longitudinal control of a motor vehicle (1), sensor data representing the surrounding environment are generated by means of an environmental sensor system (10). By means of a computing unit (4), a speed vector (8) of a traffic participant (2) in the surrounding environment is determined on the basis of the sensor data and a potential collision of the traffic participant (2) with the motor vehicle (1) is predicted. On the basis of the speed vector (8), it is determined that the traffic participant (2) is moving approximately transversely to the direction of movement (7) of the motor vehicle and a target speed for the motor vehicle (1) is calculated in order to avoid the predicted collision. The speed of the motor vehicle (1) is automatically reduced to the target speed.

Description

Technical Field

[0001] This invention relates to a method for at least partially automatic longitudinal control of a motor vehicle, wherein sensor data presenting the surrounding environment of the motor vehicle is generated by means of the vehicle's environmental sensor system, and the velocity vectors of traffic participants in the surrounding environment are determined based on the sensor data by means of the vehicle's computing unit, and potential collisions between traffic participants and the motor vehicle are predicted. The invention further relates to a corresponding vehicle control system and a motor vehicle having such a vehicle control system. Background Technology

[0002] Automatic emergency braking systems for motor vehicles are well-known. They follow an intervention strategy of intervening as late as possible so as to avoid unnecessary intervention should the driver be able to mitigate the situation through dynamic maneuvering if possible. Consequently, in such emergency braking, the vehicle brakes with a long delay.

[0003] However, such short and intense braking, which may bring the vehicle to a complete stop, can be uncomfortable for passengers in many cases because it involves a relatively large force acting on them, and the vehicle must accelerate again after the emergency braking to reach the required cruising speed.

[0004] Document DE 10 20 11 109 697A1 describes a method for operating a motor vehicle, wherein it is determined whether a turning process is introduced during driving, and whether there is a risk of collision with oncoming traffic participants. If this is the case, automatic braking intervention is triggered; however, the automatic braking intervention is aborted once, for example, the speed of the motor vehicle decreases by a preset speed difference. Summary of the Invention

[0005] In this context, the objective of the present invention is to describe an improved concept for at least partial automatic longitudinal control of motor vehicles, by which the intensity of intervention in longitudinal control is reduced, particularly when the motor vehicle is traveling straight, for example at an intersection.

[0006] This task is currently addressed by the relevant subject matter of the independent claims. Advantageous improvements and preferred embodiments are the subject matter of the dependent claims.

[0007] The improved concept is based on the idea that another traffic participant is roughly moving laterally to the vehicle, and then a target speed for the vehicle is calculated to avoid a collision with the traffic participant.

[0008] Based on an improved concept, a method for at least partially automatic longitudinal control of a motor vehicle is described, particularly when the vehicle is traveling straight, such as when or before crossing an intersection. Sensor data presenting the environment surrounding the vehicle is generated using the vehicle's environmental sensor system. Using the vehicle's computing unit, velocity vectors of traffic participants in the surrounding environment are determined based on the sensor data, and the computing unit predicts potential collisions between traffic participants and the vehicle based on the sensor data. Based on the velocity vectors, the computing unit determines that the traffic participants are moving approximately laterally to the direction of the vehicle's movement and calculates a target speed for the vehicle to avoid the predicted collision. The vehicle's speed automatically decreases to the target speed.

[0009] Longitudinal control of a motor vehicle can generally be understood as the acceleration or deceleration of the vehicle, particularly through corresponding manipulation of the drive motor or braking system. Improved conceptual methods address longitudinal control. However, this does not necessarily preclude the application of lateral control to the vehicle, such as evasive maneuvers or similar actions.

[0010] For example, a motor vehicle may have a vehicle control system for at least partially automatic longitudinal control of the motor vehicle. The vehicle control system may in particular include a computing unit and / or an environmental sensor system and / or, where possible, other controllers or actuators of the motor vehicle.

[0011] The vehicle control system here can be an electronic system designed to guide and control the motor vehicle fully automatically or autonomously, especially without driver intervention. Here, the motor vehicle or vehicle control system automatically or fully automatically performs all necessary functions, such as steering, braking and / or acceleration, observation and detection of road traffic, and related necessary responses, if necessary. In particular, the vehicle control system can be used to achieve a fully automatic or fully autonomous driving mode of the motor vehicle according to Level 5 of the SAE J3016 classification. However, the vehicle control system can also be configured as an advanced driver assistance system (ADAS) that assists the driver in partially automatic or partially autonomous driving of the motor vehicle. In particular, the vehicle control system can be designed as a safety system that can be activated by the driver independently of prior activation. In particular, the vehicle control system can be used to achieve a partially automatic or partially autonomous driving mode of the motor vehicle according to Levels 1 to 4 of the SAE J3016 classification. For example, the functionality of the vehicle control system here may be limited to the longitudinal control of the motor vehicle or the execution of methods according to improved concepts. However, this is not necessarily the case. In this context and below, "SAE J3016" refers to the corresponding standard in the June 2018 edition.

[0012] In this context and below, an environmental sensor system can be understood as a sensor system capable of generating sensor data or sensor signals that depict, present, or reflect the environment surrounding the vehicle or the environmental sensor system. In particular, the ability to detect electromagnetic or other signals from the surrounding environment is insufficient to classify a sensor system as an environmental sensor system. For example, cameras, radar systems, lidar systems, or ultrasonic sensor systems can all be understood as environmental sensor systems. In the approach according to the improved concept, an environmental sensor system may advantageously include, for example, one or more cameras, one or more radar systems, and / or one or more lidar systems.

[0013] The velocity vector of a traffic participant corresponds to its direction of motion. Correspondingly, the direction of motion of a motor vehicle can also be understood and represented as its velocity vector. The velocity vectors of traffic participants or motor vehicles can be observed here, in particular, in a lane coordinate system where the lane on which the vehicle and the traffic participant move are stationary. In this sense, the motion of a traffic participant can be understood as being approximately transverse to the direction of motion of the motor vehicle. However, actual calculations can, of course, be performed in any coordinate system.

[0014] The movement of traffic participants roughly lateral to the direction of movement of motor vehicles can be understood in this way: the lateral movement perpendicular to the direction of movement of motor vehicles is more significant than the movement component parallel to the direction of movement of motor vehicles, for example, when observed in a lane coordinate system.

[0015] In other words, for example, the calculation unit can determine that the component of the velocity vector of a traffic participant that is parallel to the direction of motion is less than the component of the velocity vector that is perpendicular to the direction of motion, so as to determine that the traffic participant is moving approximately laterally to the direction of motion of the motor vehicle.

[0016] Here, the calculation units can in particular compare the corresponding quantities of the components of the velocity vector with each other. Also here, for example, comparisons can again be made in the lane coordinate system.

[0017] For example, based on the velocity vectors of traffic participants, the computing unit can also determine that the traffic participants are moving toward the vehicle, rather than away from it. Otherwise, a corresponding collision cannot be predicted. For example, based on sensor data, in addition to the velocity vectors of traffic participants, the computing unit can also determine the positions of traffic participants, particularly relative to the vehicle. Furthermore, the computing unit may, where possible, consider digital map information of the vehicle or information from GNSS receivers. Based on the velocity vectors of the traffic participants and the vehicle, and the relative positions of the traffic participants and the vehicle, the computing unit can estimate the corresponding location and / or time of a potential collision, especially assuming the vehicle is traveling straight and, if possible, other traffic participants traveling straight, in order to predict the collision. Optionally, the computing unit may further determine information about the intentions of traffic participants, such as turning intentions or similar, based on sensor data or V2X communication, and take this information into account when predicting potential collisions.

[0018] The target speed is calculated, in particular, by means of a computational unit, such that, assuming the vehicle brakes accordingly to the target speed, a collision can be avoided with a sufficiently high probability. The target speed is here specifically less than the vehicle's current speed and is generally not equal to zero. Within the scope of this improved concept, the direction of the vehicle's velocity vector is not necessarily changed.

[0019] In order to automatically reduce the speed of a motor vehicle to a target speed, at least one control unit of the motor vehicle may operate, for example, the vehicle's braking system and / or drive motor. For example, at least one control unit may be part of a computing unit, or vice versa, or the computing unit may issue corresponding instructions to at least one control unit.

[0020] By calculating the target speed to avoid a predicted collision, it is possible to prevent unnecessary and drastic braking of the vehicle, such as bringing it to a complete stop, especially in the context of emergency braking. To this end, environmental sensor systems can be used to monitor the vehicle's surroundings at an earlier point in time, and minimizing the vehicle's speed reduction can be given high priority as the goal of the intervention strategy.

[0021] It is particularly advantageous here that traffic participants move roughly laterally to the direction of movement of the motor vehicle, because in this case, it is possible to achieve a situation where the trajectories of the traffic participants and the motor vehicle do not closely approximate each other by only slightly matching the speed of the motor vehicle, if possible.

[0022] Advantageously, the traffic participant is another motor vehicle. In this implementation, since the speed of motor vehicles is generally higher than that of, for example, pedestrians, it is more effective to slightly match the speed of the motor vehicle.

[0023] According to at least one embodiment of the method based on the improved concept, if the predicted collision can be avoided thereby, the value of the target velocity is greater than zero.

[0024] In other words, if a collision cannot be avoided by reducing the target speed in other ways—that is, if the preset minimum distance between the traffic participant and the motor vehicle is not otherwise exceeded—only full braking or braking until the vehicle comes to a stop is applied. This gives higher priority to maintaining the intensity of intervention as much as possible to achieve this goal, thereby improving user comfort for motor vehicle passengers.

[0025] According to at least one embodiment, the target speed is calculated by means of a computing unit such that the difference between the current speed of the vehicle and the target speed is minimized while avoiding a predicted collision.

[0026] Therefore, the vehicle's deceleration can be set as low as possible, and the intervention can be designed to be as comfortable as possible. Minimizing the difference between the current speed and the target speed can be achieved, in particular, by setting the intervention—the start point of speed reduction—as early as possible after a potential collision is predicted.

[0027] According to at least one embodiment, the target speed is calculated by means of a computing unit such that the predicted minimum distance between traffic participants and motor vehicles is greater than or equal to a preset minimum distance.

[0028] In particular, the computing unit can predict the respective trajectories of traffic participants and motor vehicles based on sensor data, and determine a minimum distance accordingly. The preset minimum distance can correspond to a distance in which a collision or near-collision can be ruled out with sufficient probability. For example, the computing unit can calculate the minimum distance as a function of a target speed and determine the target speed accordingly. In this implementation, the risk of a collision or near-collision can be reduced.

[0029] In particular, the target velocity is set to zero only when it cannot be guaranteed that the predicted minimum distance is greater than or equal to the minimum distance, rather than being preset to zero.

[0030] According to at least one embodiment, the target velocity is calculated by means of a computing unit in such a way that the difference between the predicted minimum distance and the preset minimum distance is minimized.

[0031] In other words, the target speed is chosen to be as high as possible while still maintaining the minimum distance. This maximizes user comfort.

[0032] According to at least one embodiment, the braking system of a motor vehicle is automatically controlled by means of the vehicle's brake control unit to automatically reduce the speed of the motor vehicle to a target speed.

[0033] In particular, the braking system actively brakes the vehicle to reduce speed, controlled by a brake control unit. This brake control unit can be part of a computing unit, or vice versa. However, the brake control unit and the computing unit can also be constructed separately. In the latter case, the computing unit and the brake control unit are in a communicative connection, allowing the computing unit to transmit the target speed or the set braking deceleration to the brake control unit.

[0034] According to at least one embodiment, the motor drive motor of a motor vehicle is automatically controlled by means of the motor control unit of the motor vehicle to automatically reduce the speed of the motor vehicle to a target speed.

[0035] In particular, the motor control unit manipulates the drive motor to reduce its torque, thereby decreasing the speed. The motor control unit can be part of a computing unit, or vice versa. However, the motor control unit and the computing unit can also be constructed separately. In the latter case, the computing unit and the motor control unit are in a communicative connection, allowing the computing unit to transmit the target speed to the motor control unit.

[0036] In particular, the active braking of a motor vehicle using the braking system can be combined with reducing the torque of the drive motor by manipulating it.

[0037] Based on the improved concept, a vehicle control system for at least partially automatic longitudinal control of a motor vehicle is also described. The vehicle control system includes an environmental sensor system configured to generate sensor data presenting the surrounding environment of the motor vehicle. The vehicle control system includes a computing unit configured to determine the velocity vectors of traffic participants in the surrounding environment based on the sensor data, and to predict potential collisions between traffic participants and the motor vehicle based on the sensor data. The computing unit is configured to determine, based on the velocity vectors, that the traffic participants are moving approximately laterally to the direction of motion of the motor vehicle. The computing unit is configured to calculate a target speed for the motor vehicle to avoid the predicted collision. Furthermore, the vehicle control system includes at least one control unit configured to operate the motor vehicle's braking system and / or the motor vehicle's drive motor to automatically reduce the speed of the motor vehicle to the target speed.

[0038] Accordingly, at least one control unit may include a brake control unit and / or a motor control unit, and may be part of a computing unit, or the computing unit may be part of at least one control unit, or at least one control unit may be constructed separately from the computing unit.

[0039] According to at least one embodiment of the vehicle control system, the environmental sensor system includes a camera and / or radar system and / or lidar system.

[0040] Further implementations of the vehicle control system based on the improved concept directly derive from various implementations of the method based on the improved concept, and vice versa. In particular, the vehicle control system is configured to execute the method based on the improved concept, or to execute such a method.

[0041] Based on the improved concept, a motor vehicle is also described, which includes a vehicle control system based on the improved concept. Attached Figure Description

[0042] The following describes embodiments of the present invention. Regarding this:

[0043] Appendix Figure 1 A schematic diagram of a motor vehicle is shown, illustrating an exemplary implementation of a vehicle control system based on an improved concept. Detailed Implementation

[0044] The embodiments explained below are preferred embodiments of the invention. In the embodiments, the described components are individual features of the invention that should be considered independently of each other, each feature also independently improving the invention, and therefore can be considered as part of the invention individually or in combinations other than those shown. Furthermore, the described embodiments may also be supplemented by additional features from the already described features of the invention.

[0045] Figure 1 The image shows a motor vehicle 1 traveling straight toward an intersection in a lane. Motor vehicle 1 has an exemplary implementation of a vehicle control system 3 based on a modified concept. Additionally, another traffic participant 2 is shown, such as another motor vehicle traveling toward intersection 9 in a different lane.

[0046] The vehicle control system 3 includes an environmental sensor system 10, which may include, for example, a camera, a radar system, and / or a lidar system. Furthermore, the vehicle control system 3 includes a computing unit 4, a braking control unit 5, and / or a motor control unit 6.

[0047] The instantaneous velocity vector 7 of vehicle 1 points from vehicle 1 along the direction of intersection 9, and the instantaneous velocity vector 8 of traffic participant 2 also points from traffic participant 2 along the direction of intersection 9. Velocity vectors 7 and 8 are therefore approximately perpendicular to each other, for example. In other words, traffic participant 2 is in lateral traffic relative to vehicle 1. Based on measurement data from environmental sensor system 10, this system can generate sensor data and transmit it to computing unit 4. Based on the sensor data, computing unit 4 can determine the velocity vector 8 of traffic participant 2, and, for example, predict a potential collision between traffic participant 2 and vehicle 1 in the area of ​​intersection 9, based on the relative position of vehicle 1 with respect to traffic participant 2 and the velocity vectors 7 and 8.

[0048] For example, calculation unit 4 can now determine, based on velocity vector 8, that traffic participant 2 is moving approximately laterally to the direction of motion of the vehicle. Calculation unit 4 can then calculate a target speed for vehicle 1, thus avoiding a predicted collision if vehicle 1's speed decreases to the target speed.

[0049] Then, the calculation unit 4 can instruct the brake control unit 5 to control the braking system (not shown) of the vehicle 1 to reduce the speed of the vehicle 1 to a target speed, and / or instruct the motor control unit 6 to control the drive motor (not shown) of the vehicle 1 to reduce the motor torque of the drive motor to reduce the speed of the vehicle 1.

[0050] The target speed is generally greater than zero. For example, this can be achieved by reducing the speed of vehicle 1 earlier, so that when vehicle 1 is in the area of ​​intersection 9, traffic participant 2 has already left the area of ​​intersection 9. In this way, a potential collision can be prevented without having to apply very strong emergency braking to vehicle 1, such as until vehicle 1 comes to a stop.

[0051] According to the improved concept, as particularly given the diagram, an intervention strategy can be implemented in which the motor vehicle brakes only to such an extent that it arrives at the potential collision site, such as the area of ​​an intersection, a sufficiently later time than other road users, in order to avert a collision. The intervention can be designed such that it is initiated early enough that a slight reduction in speed is sufficient to eliminate the risk of collision.

[0052] For example, the intervention strategy here achieves the best effect of automatic intervention as early as possible on the one hand, so as to minimize the distinction between the target speed and the initial speed. On the other hand, the intervention is advantageously performed so late that unnecessary intervention is avoided, especially from the driver's perspective, for example, if the situation is mitigated by the behavior of other road users.

[0053] Therefore, the improved concept can reduce collision risk, where the intensity or range of speed reduction is smaller compared to known methods. This can be achieved, for example, through active braking by wheel brakes, or through motor torque reduction, or a combination thereof.

[0054] List of reference numerals

[0055] 1 Motor vehicles

[0056] 2. Traffic participants

[0057] 3 Vehicle Control System

[0058] 4. Calculation Unit

[0059] 5. Brake control unit

[0060] 6. Motor control unit

[0061] 7,8 velocity vector

[0062] 9. Intersection

[0063] 10 Environmental Sensor System

Claims

1. A method for at least partially automatic longitudinal control of a motor vehicle (1), wherein - Sensor data presenting the surrounding environment of the motor vehicle (1) is generated by means of the environmental sensor system (10) of the motor vehicle (1); as well as - The computing unit (4) of the motor vehicle (1) determines the velocity vector (8) of the traffic participant (2) in the surrounding environment based on the sensor data and predicts the potential collision between the traffic participant (2) and the motor vehicle (1); Its features are, - The calculation unit (4) determines, based on the velocity vector (8), that the traffic participant (2) moves approximately laterally to the direction of motion (7) of the motor vehicle (1); - The calculation unit (4) calculates the target speed for the motor vehicle (1) to avoid a predicted collision; and - The speed of the motor vehicle (1) automatically decreases to the target speed.

2. The method according to claim 1, Its features are, By means of the calculation unit (4), it is determined that the component of the velocity vector (8) parallel to the direction of motion (7) is less than the component of the velocity vector (8) perpendicular to the direction of motion (7), so as to determine that the traffic participant (2) moves approximately laterally to the direction of motion (7) of the motor vehicle (1).

3. The method according to claim 1 or 2, Its features are, - The target velocity value is greater than zero if this would prevent a predicted collision; and / or The target speed is calculated by means of the calculation unit (4) in such a way that the difference between the current speed of the motor vehicle (1) and the target speed is minimized while avoiding a predicted collision.

4. The method according to claim 1 or 2, Its features are, The target speed is calculated by means of the calculation unit (4) such that the predicted minimum distance between the traffic participant (2) and the motor vehicle (1) is greater than or equal to the preset minimum distance.

5. The method according to claim 4, Its features are, The target velocity is calculated by means of the calculation unit (4) in such a way that the difference between the predicted minimum distance and the preset minimum distance is minimized.

6. The method according to claim 1 or 2, Its features are, The braking system of the motor vehicle (1) is automatically controlled by the braking control unit (5) of the motor vehicle (1) to automatically reduce the speed of the motor vehicle (1) to the target speed.

7. The method according to claim 1 or 2, Its features are, The motor control unit (6) of the motor vehicle (1) automatically controls the drive motor of the motor vehicle (1) to automatically reduce the speed of the motor vehicle (1) to the target speed.

8. A vehicle control system (3) for at least partially automatic longitudinal control of a motor vehicle (1), said vehicle control system (3) having: - An environmental sensor system (10) configured to generate sensor data representing the surrounding environment of the motor vehicle (1); and - A calculation unit (4) is set up to determine the velocity vector (8) of a traffic participant (2) in the surrounding environment based on the sensor data and to predict the potential collision between the traffic participant (2) and the motor vehicle (1); Its features are, - The calculation unit (4) is configured to determine, based on the velocity vector (8), the movement of the traffic participant (2) approximately laterally to the direction of motion (7) of the motor vehicle (1); - The calculation unit (4) is configured to calculate the target speed for the motor vehicle (1) in order to avoid a predicted collision; as well as - The vehicle control system (3) has at least one control unit (5,6) which is configured to operate the braking system of the motor vehicle (1) and / or the drive motor of the motor vehicle (1) to automatically reduce the speed of the motor vehicle (1) to the target speed.

9. The vehicle control system (3) according to claim 8, Its features are, The environmental sensor system (10) includes a camera and / or a radar system and / or a lidar system.

10. A motor vehicle (1) having a vehicle control system (3) according to any one of claims 8 or 9.

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