DE102013201799B4 - Driver assistance system for a vehicle and method for detecting a specific position of the vehicle - Google Patents

Abstract

Driver assistance system for a vehicle (1), comprising at least one sensor (9, 10) for generating a vehicle status signal, and a computing unit which is configured
- to record a journey route based on the vehicle status signal,
- for recognizing a specific position (2) of the vehicle (1) by comparing the recorded route with a stored route, and
- to offer a stored trajectory (4) to the driver when the specified position (2) is recognized, and
- wherein the driver assistance system is designed to control the vehicle (1) to drive autonomously or semi-autonomously along the trajectory (4),
- wherein the computing unit is designed to compare the course of the recorded and stored vehicle state signals in order to recognize the specific position (2),
- where the vehicle status signals originate from displacement sensors and/or speed sensors and/or acceleration sensors and/or tilt sensors and/or yaw rate sensors and/or speed sensors and/or steering angle sensors.

Description

State of the art

The present invention relates to a driver assistance system for a vehicle and a method for detecting a specific position of the vehicle.

Driver assistance systems can be divided into two categories: safety systems, such as emergency braking assistance, and comfort systems, such as parking assistance systems. Comfort systems provide drivers with support in an increasing number of situations, and the level of automation is constantly being raised. For example... DE 10 2008 002 598 A1 This describes an assistance system that allows the driver to automate frequently repeated driving maneuvers, such as driving into their own garage. The driver performs the maneuver manually once, and the vehicle records the trajectory. This recorded trajectory, or driving maneuver, can then be recalled, for example, at the touch of a button, with the vehicle being controlled autonomously or semi-autonomously by a processing unit.

The writing DE 10 2011 109 491 A1 Disclosing as a subsequently published prior art a driving assistance device for supporting the driving of narrow roads.

The document DE 10 2010 023 162 A1 discloses a method for assisting a driver of a motor vehicle in parking in a parking space.

The writing DE 10 2011 109 492 A1 Disclosing as a subsequently published prior art a driving assistance device for supporting the driving of narrow roads.

The document DE 10 2008 002 598 A1 discloses a device for semi-autonomous support of the steering movement of a vehicle.

Disclosure of the invention

With the driver assistance system for a vehicle according to the features of claim 1 and the method according to claim 5, it is possible to determine a specific position of the vehicle in which the driver assistance system is installed with minimal computational effort. When the specific position of the vehicle is reached, the driver assistance system offers the driver a stored trajectory. The driver can then select whether the driver assistance system should control the vehicle accordingly to follow the stored trajectory autonomously or semi-autonomously. According to the invention, the stored trajectories are therefore only offered if the vehicle is also located in the area in which the trajectory was recorded. This is achieved by a driver assistance system for a vehicle comprising at least one sensor for generating a vehicle status signal and a processing unit. Optionally, the vehicle can have a sensor for generating a vehicle status signal. The processing unit is configured to record a route. The recording of the route is based on the vehicle status signals. Optionally, the recording of the route is based on ambient signals. Furthermore, the processing unit is designed to recognize a specific position of the vehicle. This is achieved by comparing the recorded route with a stored route. It is not essential that the position be determined exactly; it is sufficient to establish that the vehicle is in an area where a trajectory was previously recorded.

Once the specified position is recognized, the processing unit offers the driver the stored trajectory. The driver can accept or reject the trajectory. The driver assistance system is designed to record trajectories and control the vehicle to autonomously or semi-autonomously follow the recorded trajectories. Several options are available for autonomous or semi-autonomous driving: The vehicle can steer, decelerate, and accelerate independently. Alternatively, the vehicle can only accelerate and decelerate, with the driver performing the steering maneuvers according to instructions. Furthermore, the vehicle can perform the steering movements independently, with the driver only accelerating and decelerating. Finally, the driver assistance system can simply provide the driver with instructions for steering, acceleration, and deceleration.

The dependent claims describe preferred embodiments of the invention.

Preferably, the processing unit is configured to permanently store previously recorded routes when a trajectory is saved. The driver assistance system continuously records the driven route. As soon as the driver decides to record a trajectory, the previously driven route can also be permanently saved. so that the starting position for the recorded trajectory is determined using the stored route.

Continuously recording the route is preferably done with minimal computing and storage resources. Therefore, the vehicle's exact position is not always determined. Only when the vehicle's position is recognized, and specifically when the driver selects to follow a saved trajectory, is the vehicle's exact position determined. This makes it possible to calculate the vehicle's exact position relative to the starting position of the recorded trajectory.

Furthermore, it is preferably provided that the processing unit is configured to store the route only for a specific segment of the route traveled and/or for a specific period of time. This storage is preferably achieved using a ring buffer, so that only the most recently traveled segment and/or the most recently traveled time is stored at any given time. For example, the route is stored only for the last 1000 meters or only for the last 10 minutes. The duration of the segment or travel time that is always stored also depends on the characteristic profile of the vehicle status signals or environmental signals. If the vehicle status signals or environmental signals have a very characteristic profile, it is sufficient to store the route for a shorter segment or a shorter period of time.

According to the invention, the processing unit is preferably configured to compare the course of the recorded and stored vehicle status signals in order to recognize the specific position. Optionally, the processing unit is preferably configured to compare environmental signals in order to recognize the specific position. Therefore, it is not absolutely necessary to derive virtual maps from the vehicle status signals or environmental signals. It is sufficient to directly compare the recorded and stored signals with each other to recognize the specific position.

To record the driving distance with minimal memory and computational effort, the invention uses only the vehicle status signals. According to the invention, at least one displacement sensor and/or speed sensor and/or acceleration sensor and/or tilt sensor and/or yaw rate sensor and/or rotational speed sensor and/or steering angle sensors are used.

Furthermore, it is possible to use environmental signals to record the route. For this purpose, sensors detect environmental features in the vicinity of the vehicle. In particular, ultrasonic sensors, cameras, stereo cameras, motion stereo cameras, lidar, or radar are used.

Furthermore, it is preferably intended that both the vehicle status signals and the environmental signals are used jointly.

The invention further comprises a method for recognizing the specific position of the vehicle, comprising the following steps: (i) recording the route traveled based on at least one vehicle status signal or environmental signal, (ii) recognizing the specific position of the vehicle by comparing the recorded route traveled with a stored route traveled, (iii) offering a stored trajectory to the driver when the specific position is recognized, and (iv) autonomously or semi-autonomously driving the trajectory with the vehicle when the driver accepts the offered trajectory.

The dependent claims of the driver assistance system according to the invention, as well as the advantageous embodiments presented within the framework of the driver assistance system according to the invention, are correspondingly advantageously applied to the method according to the invention.

A prerequisite for retrieving the stored trajectory according to the invention is the recognition of the correct starting position. There are essentially two reasons for this: The automatic maneuver (following the stored trajectory) should only be offered to the driver if the vehicle is also located in the area where the trajectory was recorded (i.e., if the vehicle is at the specified position). To allow for variations in the starting position, it is not sufficient to simply follow the recorded trajectory. Rather, the starting position of the recorded trajectory must be compared to the actual position in order to account for or compensate for this variation.

According to the present invention, the vehicle's position is detected based on common vehicle status signals, such as the steering angle, and/or simple environmental signals, such as ultrasonic sensors. This is preferably followed by an exact determination of the vehicle's position and a comparison with the starting position of the stored trajectory. This preferably involves the use of external signals or aids, as well as... Certain infrastructure elements, such as optical markers, are omitted. In particular, satellite navigation is not used for recording the route. This allows for cost-effective implementation and application without special infrastructure requirements. Furthermore, the processing unit can operate with minimal computing and storage resources.

The invention takes advantage of the fact that the route driven, for example to one's own driveway or garage entrance, remains the same in most cases. By recording this usually identical route, the specific position can be recognized. At this specific position, the driver can then be offered the stored trajectory.

According to the invention, the distance traveled, for example the last 500 m, is always recorded. If the vehicle is at the specific position where the driver activates the recording of a trajectory that he wishes to recall later, not only the subsequent maneuver but also the previously recorded course of the route is recorded. A wheel pulse counter and/or steering angle sensor and/or acceleration sensor and/or yaw rate sensor are used, in particular, to record the distance traveled.

The recognition of a specific position is achieved by comparing the current movement pattern (the recorded route) with the stored route. Correlation methods or other techniques, such as classification or regression algorithms from pattern recognition, can be used for this purpose. In addition to recognizing the specific position, the comparison can also determine the deviation between the current vehicle position or orientation and the stored trajectory.

Once the specific position is recognized, the driver is offered the saved trajectory. The specific position does not need to be recognized with absolute certainty, as the driver must first confirm the offered trajectory, for example, by pressing a control button.

The recording and storage of the route can be represented as a collection of consecutive coordinate pairs in a two-dimensional, planar coordinate system, whereby the coordinate system need not be stationary. The origin can preferably move with the vehicle. To minimize computational effort, it is also possible to use signals closely related to the traveled route instead of coordinates. The following signal combinations are preferred: steering angle profile over the distance traveled, yaw angle profile over the distance traveled, and/or wheel speed difference of two wheels on an axle over the distance traveled.

Linking the signal to the distance traveled is advantageous because the temporal signal profiles depend on the vehicle speed and are therefore potentially heavily influenced by other factors, such as environmental conditions and traffic volume. However, this does not preclude recording the speed profile along the route as a characteristic signal and using it, for example with appropriate scaling, to identify a specific position.

Since precise knowledge of the route is not required, but only its characteristic course, it is preferable to record and store only the characteristic features. Characteristic features of the route are preferably the direction and radii of curves, as well as the length of straight sections. For example, a recorded route can be described as follows: 120 m straight ahead, 60° left, 100 m straight ahead, 90° sharp right, 50 m straight ahead. Using only the characteristic features of the route has the advantage that the route can be recorded and stored with only a few signals, thus minimizing the required storage space.

Instead of relying solely on position or direction information in the horizontal plane, information about the third dimension, height, can also be incorporated. This increases the probability of accurately identifying the specific position. Preferably, a downward force can be determined from the signals of the longitudinal acceleration sensor, which actually provides a force along the vehicle's longitudinal axis, and the vehicle's longitudinal acceleration calculated from changes in wheel speed. This allows for an approximate determination of the road's gradient. A (relative) elevation profile of the traveled route can then be created, which can be used either as an alternative or supplement to identify the specific position.

Using vehicle status signals has the advantage of being independent of environmental influences. For example, there is no need to differentiate between stationary and other signals. Objects are detected, which requires complex procedures for processing environmental signals.

Nevertheless, it is also preferred to use environmental signals in addition to or as an alternative to the vehicle status signals. These environmental signals detect features in the vicinity of the vehicle. Preferably, camera systems installed in the vehicle are used to detect and classify these environmental features, such as traffic lights, road signs, roundabouts, or road markings.

Using distance-measuring sensors, such as lidar, radar, ultrasound, stereo video cameras, and motion stereo video cameras, a local environment map can be created during travel using established methods. Characteristic features can then be extracted from this map and used to recognize the specific position. Advantageously, stationary objects are used as features for this purpose. Parked vehicles and dynamic objects can be detected and filtered out using appropriate techniques.

The use of environmental signals can also be achieved with minimal computational and storage requirements. For example, only the distance of environmental features to the vehicle along the driving route is measured.

The following describes the process for recording a trajectory and recognizing the specified position: First, while driving, the processing unit records the vehicle status signals and/or environmental signals for the route and stores the relevant values or derived characteristics in volatile memory. Data older than 500 meters, for example, is deleted from the volatile memory. When the memory limit is reached, for example, when using ring buffers, the oldest data is deleted. If the driver then activates trajectory recording, the data previously held in volatile memory for the recorded route is permanently saved in non-volatile memory. The volatile memory thus freed up can be used to record the trajectory until it is also saved to the non-volatile memory after reaching the target position.

When the driver assistance system or the corresponding procedure is in "search mode," the signal patterns or features stored in volatile memory are compared with the data on the saved route stored in non-volatile memory. If a correlation is found, the system recognizes the specific position. The saved trajectory can then be offered to the driver via a suitable human-machine interface. If the driver activates the offered trajectory, the vehicle is localized by comparing the signals or features in the volatile and non-volatile memory. This means that the relative deviation between the current vehicle position and the starting position of the saved trajectory is determined. To determine this actual, current position of the vehicle, more complex calculation methods, such as multi-stage optimization procedures or additional aids like GPS, can be used.

Initially, only the determined position is recognized. This can be achieved with relatively little storage and processing power. Only then does the actual position of the vehicle need to be determined more precisely in order to calculate the deviation from the starting position of the trajectory. Only then does the computationally intensive transformation of the trajectory data into the valid coordinate system take place.

Brief description of the drawings

• 1 den Verlauf einer Trajektorie für das erfindungsgemäße Fahrerassistenzsystem gemäß allen Ausführungsbeispielen,
• 2 Umfeldsignale des erfindungsgemäßen Fahrerassistenzsystem gemäß einem ersten Ausführungsbeispiel,
• 3 das Aufzeichnen einer Fahrstrecke für das erfindungsgemäße Fahrerassistenzsystem gemäß einem zweiten Ausführungsbeispiel, und
• 4 Umfeldsignale für das erfindungsgemäße Fahrerassistenzsystem gemäß einem zweiten Ausführungsbeispiel.

Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawing.

• 1 the course of a trajectory for the driver assistance system according to the invention in all embodiments,
• 2 Environmental signals of the driver assistance system according to a first embodiment according to the invention,
• 3 recording a route for the driver assistance system according to a second embodiment of the invention, and
• 4 Environmental signals for the driver assistance system according to a second embodiment.

Embodiments of the invention

Two exemplary embodiments of the invention are described below. Identical or functionally identical components and objects are provided with the same reference numerals.

1 Figure 1 shows a top view of a parking lot for both embodiments. A vehicle 1 with an integrated driver assistance system is located at the entrance to the parking lot. Vehicle 1 is at a specific position 2. Furthermore... shows 1 A trajectory 4 stored in the driver assistance system. This trajectory 4 begins at a starting position 3 and guides the vehicle 1 autonomously or semi-autonomously to parking space 5. The trajectory 4 was manually followed once by the driver, starting from the starting position 3, and recorded by the driver assistance system.

According to the invention, the driver assistance system recognizes that the vehicle 1 is at the specified position 2 and therefore offers the driver the option of autonomously following the stored trajectory 4. If the driver confirms this, the vehicle 1 either autonomously drives along the trajectory 4 or gives the driver further instructions for steering and/or accelerating in order to follow the trajectory 4.

According to the invention, it is possible to determine whether the vehicle 1 is located at the specified position 2 with as little storage and computing effort as possible.

In the first embodiment, various sensors are used to generate environmental signals. These sensors, for example lidar, radar, ultrasound, or cameras, detect various environmental features. 2 For example, the recorded environmental signals 6 are shown. Based on these environmental signals 6, it can be seen that the vehicle 1 is moving towards an intersection 8 between parked cars 7.

The characteristic pattern of the environmental signals 6 is recorded. As soon as the vehicle 1 travels the same route again, the recorded environmental signals 6 are compared with the stored environmental signals 6. This allows the driver assistance system to recognize that it is moving towards the specific position 2.

Instead of recording the environmental signals 6, vehicle status signals, for example via the steering angle, acceleration or distance traveled, can also be used.

3 and 4 Figure 1 shows a second embodiment. In this second embodiment, a right ultrasonic sensor 9 and a left ultrasonic sensor 10 are used on the vehicle 1. The two ultrasonic sensors 9, 10 only detect the distance to surrounding features, for example, posts 11.

4 Figure 6 shows the course of the environmental signals. A first signal (12) shows the signal course of the left ultrasonic sensor (10). A second signal (13) shows the course of the right ultrasonic sensor (9). The X-axis (14) shows the travel path. The Y-axis (15) shows the measured distance.

The second embodiment shows that very simple signal waveforms, requiring correspondingly little computational and storage resources, can be used to capture characteristic features and thus to identify the specific position 2. In the example shown, the two posts 11 are particularly easy to detect using the ultrasonic sensors 9 and 10.

A further reduction in the amount of data can preferably be achieved by adding the sensor signals. This yields a resulting signal profile that correlates, for example, with the passage width between the two posts 11. Furthermore, any lateral offset of the vehicle position does not need to be taken into account when comparing the signals.

Claims (7)

Driver assistance system for a vehicle (1), comprising at least one sensor (9, 10) for generating a vehicle status signal, and a processing unit configured: - to record a route based on the vehicle status signal, - to recognize a specific position (2) of the vehicle (1) by comparing the recorded route with a stored route, and - to offer a stored trajectory (4) to the driver when the specific position (2) is recognized, and - wherein the driver assistance system is configured to control the vehicle (1) to autonomously or semi-autonomously follow the trajectory (4), - wherein the processing unit is configured to compare the history of the recorded and stored vehicle status signals in order to recognize the specific position (2), - wherein the vehicle status signals are derived from displacement sensors and/or speed sensors and/or acceleration sensors and/or tilt sensors. and/or yaw rate sensors and/or speed sensors and/or steering angle sensors. Driver assistance system according to Claim 1 , characterized in that the computation unit is designed to permanently store the previously recorded route when a new trajectory (4) is stored. Driver assistance system according to one of the preceding claims, characterized in that the computing unit is designed for this purpose. is to determine an exact position of the vehicle (1) relative to the starting position (3) of the stored trajectory (4) only after recognizing the determined position (2). Driver assistance system according to one of the preceding claims, characterized in that the calculation unit is designed to store the driving distance only over a certain previously traveled section and/or over a certain previously traveled time, preferably by means of a ring buffer. A method for detecting a specific position (2) of a vehicle (1), comprising the following steps: - Recording a route based on at least one vehicle state signal, - Recognizing the specific position (2) of the vehicle (1) by comparing the recorded route with a stored route, - Offering a stored trajectory (4) to the driver when the specific position (2) is detected, - Driving the trajectory (4) autonomously or semi-autonomously when the driver accepts the offered trajectory (4), and - Comparing the history of the recorded and stored vehicle state signals to detect the specific position (2), - wherein the vehicle state signals are derived from displacement sensors and/or speed sensors and/or acceleration sensors and/or tilt sensors and/or yaw rate sensors and/or rotational speed sensors and/or steering angle sensors. Procedure according to Claim 5 , characterized in that when a new trajectory (4) is stored, the previously recorded route is permanently stored. Procedure according to one of the Claims 5 or 6 , characterized in that the route is stored only for a specific past section of the route and/or for a specific past travel time.