Sensor system for a vehicle to detect bridges or tunnel entrances

Abstract

Sensor system (100) for a vehicle (200) for detecting bridges (300) and tunnels (310), comprising: - a lateral lidar sensor (110) arranged on a first side of the vehicle (200) with a detection area (111) covering a lateral environment of the vehicle (200), - a control device (160) for evaluating measurement data of the lateral lidar sensor (110), wherein the lateral lidar sensor (110) is arranged rotated about its vertical axis (114) so that a front part (112) of the detection range (111) of the lateral lidar sensor (110) in the direction of travel detects an upper spatial area (400) arranged in front of the vehicle (200) at a predetermined distance (410), and wherein the lateral lidar sensor (110) is further tilted about its transverse axis (113) relative to the horizontal, so that the detection area (111) of the lateral lidar sensor (110) detects the remote upper spatial area (400) at a predetermined height (420) with its front part (112) in the direction of travel.

Description

[0001] The invention relates to a sensor system for a vehicle for detecting bridges or tunnel entrances. Furthermore, the invention relates to a vehicle with such a sensor system and a method for detecting bridges or tunnel entrances. State of the art

[0002] The document DE 10 2004 015 749 A1 discloses a device for determining the possibility of passage for a vehicle past obstacles.

[0003] The document DE 10 2008 029 613 A1 describes a collision avoidance system for reducing false alarms by estimating the elevation of a target object.

[0004] The document US 2015 / 0 131 080 A1 discloses an array-based LiDAR unit comprising a transmitter / receiver arrangement configured to cover a field of view for the unit.

[0005] The document DE 103 51 915 A1 describes a monitoring device for a motor vehicle, wherein the monitoring device has a sensor device for detecting obstacles in front of or behind the motor vehicle and an evaluation device for checking the presence of an obstacle within a monitoring area a predetermined distance from the motor vehicle as a function of an output value of the sensor device.

[0006] The document DE 10 2013 222 846 A1 discloses a method for detecting the possibility of a vehicle passing through, in which the road area ahead in the direction of travel of the vehicle and the clearance height of a passage ahead in the direction of travel are detected by means of an environmental detection system and fed to a data processing device, wherein the data processing device generates a warning message based on the maximum vehicle height if the clearance height is insufficient.

[0007] Modern vehicles are equipped with a multitude of sensors for detecting objects in the vehicle's surroundings. The information obtained is used to control a variety of assistance systems that support the driver and, if necessary, can intervene independently in the driving process. For partially and, above all, highly automated or autonomous driving systems, particularly reliable detection of the vehicle's surroundings is required. This environmental information then serves as the basis for decisions, such as whether to change lanes. To enable extremely reliable detection of the vehicle's surroundings, several sensors and / or sensor technologies, such as radar, lidar, video, or similar, are installed on the vehicle in such a way that the most complete 360° panoramic view possible is achieved. The various sensor technologies have specific advantages and disadvantages.For example, some of the environmental sensors used in vehicles today, such as lidar or radar sensors, only have a horizontal field of view. Radar sensors can, for example, detect that an object is within the driving range. However, especially at a great distance, the object cannot be classified as a bridge with sufficient probability. Even if the object is detected as a bridge, the insufficient discrimination ability in the evelation angle makes it impossible to decide whether there is another stationary object underneath the bridge. Even with horizontally aligned lidar sensors or laser scanners, detection is almost impossible due to the limited vertical field of view. With video sensors, on the other hand, it is not possible to reliably detect a bridge or whether it is clear at a sufficient distance due to the low resolution.This is especially true in poor visibility conditions.

[0008] Due to the lack of a vertical field of view and the limited elevator separation capability, these sensors are unable to directly measure the underpassability of a bridge. Currently available sensors exhibit functional deficiencies, particularly in cases where a stationary vehicle blocks the passage.

[0009] To prevent braking for every static object near the road, such as a bridge or tunnel entrance, current driver assistance systems can wait until the object has been reliably identified as an obstacle before braking. However, this strategy is not a viable solution for highly automated systems.

[0010] Due to the limited elevator separation capability of sensors and sensor arrangements currently available in the automotive sector, the adequate detection of the ability to drive under or through bridges and tunnel entrances represents a fundamental problem. Disclosure of the invention

[0011] The object of the invention is therefore to provide a means for detecting bridges and tunnels, as well as any obstacles in their passage or entrance area. This object is achieved by a sensor system according to claim 1, a vehicle according to claim 10, and a method according to claim 11. Further advantageous embodiments are specified in the dependent claims.

[0012] According to the invention, a sensor system for a vehicle for detecting bridges and tunnels is provided, which comprises a lidar sensor arranged on a first side of the vehicle with a detection range covering a lateral area of the vehicle, and a control device for evaluating the measurement data or signals from the lateral lidar sensor. The lateral lidar sensor is arranged rotated about a vertical axis so that a front part of the detection range of the lateral lidar sensor, as seen in the direction of travel, detects an upper spatial area arranged in front of the vehicle at a predetermined distance. The lateral lidar sensor is further tilted about a transverse axis relative to the horizontal so that the detection range of the lateral lidar sensor, with its front part, as seen in the direction of travel, detects the distant upper spatial area at a predetermined height.This special alignment of the lateral lidar sensor makes it possible to detect objects located at a specific height in front of the vehicle. In particular, it allows the detection of superstructures of bridges, tunnels, or other structures spanning the roadway, such as traffic signs, at a sufficient distance in front of the vehicle. The ability to use lateral lidar sensors to detect the superstructure of bridges, traffic signs, or similar structures spanning the roadway, or the outer wall above a tunnel entrance, proves particularly advantageous, as these lidar sensors are already present in a vehicle trained for automated driving due to the required 360° panoramic view, and therefore no additional sensors are needed. This means no additional costs arise.

[0013] Furthermore, the use of lidar sensors makes the detection method largely independent of external lighting conditions. Since detecting bridges at a certain distance requires only a relatively small rotation of the lateral lidar sensor, rotating the sensor does not result in any significant detriment to the lateral all-round view.

[0014] With the help of the special sensor arrangement, driving comfort can be significantly increased, as bridges and their ability to be driven under are detected at an early stage and autonomous braking is no longer necessary when the ability to drive under or through them is detected.

[0015] In one embodiment, a front sensor device is further provided for detecting the surroundings to the front of the vehicle below the remote upper spatial area. The control device is designed to evaluate the ability to pass through a tunnel or underpass a bridge based on the measurement data or signals from the lateral lidar sensor and the front sensor device. The combination of the upwardly directed, tilted lateral lidar sensor with another sensor in the front area of the vehicle that detects the surroundings essentially horizontally makes it possible to reliably detect bridges, tunnels, and other structures spanning the roadway and, at the same time, to make a statement about the presence of obstacles in the area of these objects.

[0016] According to a further embodiment, the control device is configured to evaluate a distant spatial area in front of the vehicle as an obstacle if the side lidar sensor does not detect an object while the front sensor device detects an object. This special evaluation makes it possible to detect blocked or impassable bridge underpasses and tunnel passages in a timely manner. As a result, appropriate measures, such as automatic braking of the vehicle, can be initiated early.

[0017] In a further embodiment, the control device is configured to evaluate a distant spatial area in front of the vehicle as a passable tunnel or a passable bridge if the side lidar sensor detects an object while the front sensor device does not detect an object. This special design of the control device allows the passability of bridges and tunnels to be detected with greater certainty. As a result, the journey can continue without reducing speed.

[0018] In a further embodiment, the control device is configured to evaluate a distant spatial area in front of the vehicle as a tunnel with a passability impaired by an obstacle, or as a bridge with a passability impaired by an obstacle, if the lateral lidar sensor detects an object and the front sensor device also detects an object. This special design of the control device allows obstacles in the area of bridges and tunnels to be detected with particular reliability.

[0019] In a further embodiment, the front sensor device is designed in the form of a radar sensor. The combination of the specially arranged lateral lidar sensor with the front radar sensor forms an optimal sensor combination for reliably detecting the underpassability of bridges or the passability of tunnels. The radar sensor provides reliable detection of objects in front of the vehicle without, however, allowing any statement about the height of a detected object. The combination of a corresponding radar sensor with the specially arranged lateral lidar sensor, on the other hand, compensates for the inadequate evelatory resolution of the radar sensor and thus enables particularly reliable detection of bridges and tunnels, as well as their passability.

[0020] In a further embodiment, the front sensor device is designed as a front lidar sensor. The front lidar sensor also enables good detection of objects in front of the vehicle due to its horizontal detection range. The combination of the front lidar sensor with the specially upward-facing side lidar sensor opens up the possibility of expanding the narrow evelatory field of view of the front lidar sensor in a way that enables reliable detection of bridges and tunnels, and their passability.

[0021] In a further embodiment, the control device is configured to determine whether a tunnel can be driven through or a bridge can be driven under based on the raw data from the side lidar sensor and the front sensor device. The distances between the reflections are evaluated using geometric relationships. This can significantly reduce the computational effort.

[0022] In a further embodiment, a second lateral lidar sensor is provided on a second side of the vehicle opposite the first side, arranged in a mirror image of the lateral lidar sensor. The second lateral lidar sensor is also arranged rotated about a vertical axis and further tilted about a transverse axis relative to the horizontal, so that a front part of the detection range of the second lateral lidar sensor, in the direction of travel, detects the upper spatial area in front of the vehicle at a predetermined distance and at a predetermined height above the vehicle. The arrangement of the specially aligned lidar sensors on both sides can significantly improve the detection of the superstructures of bridges and tunnels, as well as obstacles in these areas.

[0023] The invention is described in more detail below with reference to the drawings. These show: Fig. 1 schematically shows a top view of a vehicle with two side lidar sensors and one front sensor as well as the detection ranges of the respective sensors; Fig. 2 a schematic representation of the vehicle and a tunnel entrance in front of the vehicle as well as the forward-facing detection areas of the side and front sensors; Fig. 3 a schematic representation of a bridge arranged in front of the vehicle and the detection areas of the vehicle sensors; Fig. 4 a schematic representation of a bridge with an underpass blocked by an obstacle and the detection areas of the forward-facing vehicle sensors covering the bridge and the obstacle; Fig. 5 a schematic representation of a lateral lidar sensor and its reference system to illustrate the rotation of the first lateral lidar sensor; and Fig. 6 a schematic representation of the sensor system arranged in the vehicle.

[0024] Due to the limited evelatory separation capability of sensors and sensor arrangements currently available in the automotive sector, there is a problem with detecting whether bridges and tunnel entrances can be driven under or through. The sensor system according to the invention, comprising a sensor arrangement and a corresponding control device, enables robust detection of whether bridges and tunnels can be driven under or through without the need for additional or novel sensors. The specific arrangement of the sensors and a corresponding method for evaluating the measured data make it possible to detect whether a bridge is within the driving range and whether there is an obstacle underneath the bridge or whether the bridge can be safely driven under.

[0025] By cleverly integrating multiple lidar sensors, the elevation resolution of the sensor array can be expanded. This allows a vertical field of view to be covered, allowing the differentiation of bridges and tunnel entrances, as well as the ability to drive under or through them. The Fig. 1 a plan view of a vehicle 200 with a sensor arrangement comprising a first lateral lidar sensor 110 arranged on the left side of the vehicle, a second lateral lidar sensor 120 arranged on the right side of the vehicle and a front lidar sensor 130 arranged in the front area of the vehicle 200. While the front lidar sensor 130 scans the area in front of the vehicle 200 horizontally, the two lateral lidar sensors 110, 120 essentially cover the right and left lateral area of the vehicle 200. In the Fig. 1, the corresponding detection areas 111, 121, 131 of the three lidar sensors 110, 120, 130 are indicated by a dashed line, whereby for reasons of clarity, only the parts of the detection areas closest to the vehicle are shown. In order to detect a given upper spatial area at a given distance, the two lateral lidar sensors 110, 120 are each rotated about a vertical axis in the direction of travel, with the left lateral lidar sensor 110 in Fig. 1 are rotated clockwise and the right vertical lateral lidar sensor 120 is rotated counterclockwise. As a result, the first lidar sensor 110, arranged on the left, looks into an area in front of the vehicle 200 with the right edge region 112 of its detection range 111. Accordingly, the second lidar sensor 120, arranged on the right, looks into the area in front of the vehicle 200 from the right with the left edge region 122 of its detection range 121. The angles of rotation of the two lateral lidar sensors 110, 120 can be selected such that the two detection ranges 111, 121 overlap at a predetermined distance.

[0026] In order to be able to detect the superstructure of a bridge or a tunnel at a predetermined distance, the two lateral lidar sensors 110, 120 are each tilted about a transverse axis 113, 123 relative to the horizontal, so that the laser beams of the two lidar sensors 110, 120, which are directed forward in the direction of travel, detect an upper spatial area to be detected at a predetermined distance and predetermined height above the roadway or above the vehicle.

[0027] In the Fig. Figure 2 schematically shows a vehicle 200 scanning a tunnel entrance located in front of the vehicle. Lidar sensors typically scan their surroundings in multiple, superimposed planes. The total aperture angle of the laser scanner perpendicular to the scanning direction, which is determined by the number of scanning planes and their angles to one another, can vary depending on the application. To illustrate that a laser scanner typically comprises multiple scanning planes, each offset by a small angle to one another, the detection range of the front lidar sensor 130 is represented by four dashed lines.It can be seen that the essentially horizontally emitted scanning beams 131 of the front lidar sensor 130 only detect the right and left outer walls 311, 312 of the tunnel 310 and radiate into a central region of the tunnel, while the scanning beams 121 of the lateral lidar sensor 120, which are directed upwards due to the tilt relative to the horizontal, detect in particular an upper spatial region 400 in which the part of the outer wall of the tunnel 310 arranged above the tunnel entrance 314 is located. Fig. 2 further shows that by selecting a suitable tilt angle, the distance 410 and height 420 of the upper spatial region 400 detected by the edge beams 122 can be adjusted. This tilt angle can be varied as needed, with a relatively small tilt angle being selected for the earliest possible detection. The typical heights of bridges, for example, can serve as criteria for the beam direction and the modified detection range of the lateral lidar sensors 110, 120.

[0028] The Fig. 3 shows a schematic representation of a bridge 300 arranged in front of the vehicle in the direction of travel. To clarify the measuring principle of the sensor system according to the invention, the detection areas, which typically comprise several scanning planes offset from one another, of the Fig. 1 is represented by four dashed lines each. It can be seen that the essentially horizontally oriented detection area 131 of the front lidar sensor 130 detects the left and right bridge piers 301, 302 and, with its central section, looks into the bridge underpass 304. In contrast, the detection areas 111, 121 of the two lateral lidar sensors 110, 120 are directed at the bridge superstructure 303 arranged at a predetermined height 420. By evaluating the measurement data, the control device of the sensor system can detect a structure spanning the roadway 320 based on the detected objects 301, 302, 303, such as a bridge, a tunnel, or a road sign arranged above the roadway. Since the front lidar sensor 330 does not detect any object in the area of the bridge underpass 304 in the present case, the detected bridge 300 is classified as passable.As a result, the journey can continue unhindered.

[0029] However, if an obstacle 330, such as a vehicle, is located in the area of the tunnel passage 304, this obstacle 330 is detected by the scanning beams 131 of the front lidar sensor 130 in the corresponding area. As a result, the detected overall structure is classified as a bridge 300 that cannot be driven under due to an obstacle 330 blocking the bridge underpass 304. As a result, appropriate measures, such as slowing down the vehicle, can be taken. A corresponding situation is described in the Fig. 4 shown.

[0030] If an object is detected only by the front lidar scanner 130 in a lower spatial area 430 below the upper spatial area 400, while the side lidar scanners 110, 120 do not detect a corresponding object in the lower spatial area 400, the detected object is classified as an obstacle. Appropriate measures, such as slowing down the vehicle, can also be taken in this case.

[0031] In addition to the front lidar sensor 130, the vehicle 200 can also be equipped with a forward-facing radar sensor. Such a radar sensor allows the detection of a static object in front of the vehicle. Since the radar measurement data cannot be used to determine whether this is an obstacle blocking the roadway or a bridge that can be driven under, it is useful to perform a joint evaluation of the measurements from the radar sensor and the lidar sensors. Thus, if the radar sensor detects a static object, while the front lidar sensor does not detect any object in the roadway area and the two side lidar sensors detect objects accordingly, the object detected by the radar sensor can be classified as not being an obstacle. In this case, the object detected by the radar sensor is highly likely to be a bridge that can be driven under.

[0032] In automated driving, for example, if the side lidar scanner detects no object while the front lidar scanner detects an object, or if both the side lidar scanner and the front lidar scanner detect an object, the speed can be reduced or the vehicle can be decelerated to a stop. However, if the side lidar scanner detects an object and the front lidar scanner does not, the journey can continue as planned without additional maneuvers.

[0033] The Fig. Figure 5 illustrates the rotation of a lateral lidar sensor performed within the scope of the modification proposed here. For this purpose, the first lateral lidar sensor 110, arranged on the left side of the vehicle, is shown schematically in a highly simplified representation. The triangle 111, represented by a dashed line, illustrates the scanning plane of the sensor 110 in the initial state. The lidar sensor 110 preferably has its own coordinate system (x1, y1, z1), which depends on the installation location and orientation of the lidar sensor and therefore cannot be compared with the Fig. 1. The x1 coordinate axis corresponds to the main beam direction of the laser scanner 110. The corresponding transverse axis 113 of the sensor 110 is represented by a dash-dot line. The transverse axis 113 preferably corresponds to the main beam axis of the laser scanner. Depending on the design of the sensor, however, the transverse axis and the main beam axis may also differ from one another. Furthermore, the z1 coordinate axis corresponds to the vertical axis 114 of the sensor, also represented by a dash-dot line, which is preferably oriented vertically in the initial state. By rotating the sensor 110 about the vertical axis 114 and simultaneously tilting the sensor about its transverse axis 113, the detection area 111 of the sensor 110 moves from its original position to the inclined plane 111', which is represented by the dotted line.

[0034] The Fig. 6 shows a highly simplified representation of a vehicle 200 with a sensor system 100 according to the invention. The sensor system 100 comprises a sensor arrangement consisting of two lateral lidar sensors 110, 120 arranged on opposite sides of the vehicle, as well as a front lidar sensor 130 arranged in the front of the vehicle and directed forward. Furthermore, an additional radar sensor 140 is also provided, which is installed in the front of the vehicle and has a forward-facing detection range. The lidar sensors 110, 120, 130 and the radar sensor 140 are connected to a common control device 160. The control device 160 can be designed as part of a higher-level control device (not shown here). Furthermore, the control device 160 can form a higher-level control instance combining several control units.

[0035] As in the Fig.As shown schematically in Figure 5, the sensors 110 to 140 can be connected to the control device 160 via separate connecting lines. Alternatively, the sensors 110 to 140 can be connected to the control device 160 both individually and in groups via a common bus connection. The sensor system 100 shown here as an example can also include additional sensors installed in the vehicle.

[0036] The cases described above can be expanded to include additional cases as needed. This is particularly useful when detecting objects using multiple sensors and there is a high degree of uncertainty regarding the classification of the detected objects. In this respect, the evaluation algorithm can in principle also be expanded to include additional cases. For example, additional measurement data and information can be incorporated into the decision as to whether an object detected in front of the vehicle is a bridge or a tunnel, and whether the bridge passage or tunnel entrance is blocked by an obstacle. Based on the evaluation of the sensor measurement data, the control device can decide whether driving maneuvers should be initiated to rule out a hazard posed by an obstacle impeding the lane.

[0037] Although the invention has been described above using specific embodiments, it is by no means limited thereto. Those skilled in the art will thus be able to appropriately modify and combine the described features without deviating from the essence of the invention.

Claims

[1] Sensor system (100) for a vehicle (200) for detecting bridges (300) and tunnels (310) comprising: - a lateral lidar sensor (110) arranged on a first side of the vehicle (200) with a detection area (111) covering a lateral environment of the vehicle (200), - a control device (160) for evaluating measurement data of the lateral lidar sensor (110), wherein the lateral lidar sensor (110) is arranged rotated about its vertical axis (114) so that a front part (112) of the detection range (111) of the lateral lidar sensor (110) in the direction of travel detects an upper spatial area (400) arranged in front of the vehicle (200) at a predetermined distance (410), and wherein the lateral lidar sensor (110) is further tilted about its transverse axis (113) relative to the horizontal, so that the detection area (111) of the lateral lidar sensor (110) detects the remote upper spatial area (400) at a predetermined height (420) with its front part (112) in the direction of travel. [2] Sensor system (100) according to claim 1, further comprising a front sensor device (130) for detecting a front environment of the vehicle (200) below the remote upper space area (400), wherein the control device (160) is designed to evaluate the passability of a tunnel (310) or the passability of a bridge (300) based on the measurement data of the lateral lidar sensor (110) and the front sensor device (130). [3] Sensor system (100) according to claim 2, wherein the control device (160) is designed to evaluate a distant spatial area in front of the vehicle (200) as an obstacle, when the side lidar sensor (110) does not detect an object while the front sensor device (130) detects an object. [4] Sensor system (100) according to claim 2 or 3, wherein the control device (160) is designed to evaluate a remote spatial area in front of the vehicle (200) as a drive-through tunnel (310) or as a drive-under bridge (300), when the side lidar sensor (110) detects an object while the front sensor device (130) does not detect an object. [5] Sensor system (100) according to one of claims 2 to 4, wherein the control device (160) is designed to evaluate a remote spatial area in front of the vehicle (200) as a tunnel (310) with a passability impaired by an obstacle or as a bridge (300) with a passability impaired by an obstacle, when the side lidar sensor (110) detects an object and the front sensor device (130) also detects an object. [6] Sensor system (100) according to one of the preceding claims 2 to 5, wherein the front sensor device (130) is designed in the form of a front lidar sensor. [7] Sensor system (100) according to claim 6, wherein a front radar sensor (140) is additionally provided, and wherein the control device (160) is designed to evaluate the remote spatial area (400) in front of the vehicle (200) as a drive-through tunnel (310) or as a drive-under bridge (300), when the radar sensor (140) detects an object while the side lidar sensor (110) detects an object and the front lidar sensor (130) does not detect an object. [8] Sensor system (100) according to one of the preceding claims, wherein the control device (160) is designed to determine the passability of a tunnel (310) or the passability of a bridge (300) based on the raw data of the lateral lidar sensor (110) and the front sensor device (130), where the distances of the reflections are evaluated using geometric relationships. [9] Sensor system (100) according to one of the preceding claims, wherein a second lateral lidar sensor (120) arranged in a mirror image of the lateral lidar sensor (110) is provided on a second side of the vehicle (200) opposite the first side. [10] Vehicle (200) with a sensor system (100) according to one of the preceding claims 1 to 9. [11] Method for detecting bridges (300) and tunnels (310) in front of a vehicle (200) comprising: - scanning an upper spatial area (400) arranged at a predetermined distance (410) and at a predetermined height (420) in front of the vehicle (200) by means of a lateral lidar sensor (110) arranged on one side of the vehicle (200) rotated about its vertical axis (114) and tilted about a transverse axis (113) relative to the horizontal, - scanning a remote lower spatial area (430) below the remote upper spatial area (400) using a front sensor device (130) for detecting a front environment of the vehicle (200), and - Assessing the passability of a tunnel (310) or the passability of a bridge (300) based on the measurement data of the lateral lidar sensor (110) and the front sensor device (130). [12] Method according to claim 11, wherein a distant spatial area in front of the vehicle (200) is assessed as an obstacle, when the side lidar sensor (110) does not detect an object while the front sensor device (130) detects an object. [13] Method according to claim 11 or 12, wherein a distant spatial area in front of the vehicle (200) is assessed as a passable tunnel (310) or as a passable bridge (300), when the side lidar sensor (110) detects an object while the front sensor device (130) does not detect an object. [14] Method according to one of claims 11 to 13, wherein a distant spatial area in front of the vehicle (200) is assessed as a tunnel (310) with a passability impaired by an obstacle or as a bridge (300) with a passability impaired by an obstacle when the lateral lidar sensor (110) detects an object and the front sensor device (130) also detects an object. [15] Method according to one of claims 11 to 14, wherein a spatial area arranged in front of the vehicle (200) is scanned by means of an additional front radar sensor (140) for detecting a front environment of the vehicle (200), and wherein a distant spatial area in front of the vehicle (200) is assessed as a passable tunnel (310) or as a passable bridge (300), when the radar sensor (140) detects an object while the side lidar sensor (110, 120) detects an object and the front lidar sensor (130) does not detect an object.

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