Occupancy card for a vehicle

Abstract

Method for providing an occupancy map (100) for a vehicle (F), comprising the steps: - determining a driving situation of the vehicle (F) by means of a determination device (200); and - Adapting a configuration of the occupancy map (100) depending on the driving situation, characterized by the step: - Determining a detection characteristic for a sensor device (S1, S2, S3) of the vehicle (F) from the occupancy map (100).

Description

The invention relates to an occupancy map for a vehicle. Furthermore, the invention relates to a method for providing an occupancy map for a vehicle.Prior ArtThe post-published laid-open specification EP 2 600 328 A1 discloses a device for driving assistance.The patent specification DE 44 08 328 A1 discloses a method for creating a cellularly structured environment map from a self-moving mobile unit.The laid-open specification DE 10 2010 011 629 A1 discloses a method for the environmental representation of a vehicle.The post-published laid-open specification DE 10 2013 207 904 A1 discloses a method for providing a map of the surroundings for a vehicle.The post-published laid-open specification DE 10 2013 200 387 A1 discloses a method for creating an obstacle map of a surroundings of a motor vehicle on a road.Laid-open specification US 2008 / 0 252 433 A1 discloses a method for supporting driving of a vehicle.In the prior art, automated driving or driving assistance functions (e.g. ACC, lane change assistant, parking assistant, lane keeping assistant, etc.) for vehicles or automated vehicles are known, which may be dependent on a representation of the vehicle environment. For this purpose, so-called occupancy maps (occupancy grid maps, see e.g. in: "Probabilistic Robotics" by Thrun, Burgard, Fox, ISBN-10:0262201623) can be used, the cells of which can assume defined states. The individual cells of the occupancy map are often aligned in the direction of the longitudinal and transverse axes of the vehicle and generally have edge sections arranged at right angles to one another.An essential task of the occupancy map mentioned is to describe the vehicle environment. Based on this description, the vehicle behavior is planned, whereby the vehicle can react appropriately to other road users, for example. The representation of the environment is possible in different coordinate systems, known is a representation in Cartesian coordinates or in polar coordinates.Disclosure of the InventionIt is an object of the invention to provide an improved occupancy map for a vehicle.According to a first aspect, the object is achieved with an occupancy map for a vehicle, comprising a plurality of cells arranged in a grid-like manner. The occupancy map is characterized in that the cells of the occupancy map are adapted to the driving situation depending on a driving situation of the vehicle. This advantageously provides an information-optimized representation of the occupancy map, in which only those information are calculated that are actually required. Under certain circumstances, a computing effort can even be reduced compared to conventional occupancy maps. A vehicle is thus provided with data in a form which is better adapted to the respective driving situation.According to a second aspect, the object is achieved by a method for providing an occupancy map for a vehicle, comprising the steps:determining a driving situation of the vehicle by means of a determination device; andadapting a configuration of the occupancy map as a function of the driving situation.Preferred embodiments of the occupancy map and the method are the subject of dependent claims.A preferred embodiment of the occupancy map according to the invention is characterized in that the cells of the occupancy map are arranged in one of the following coordinate systems: Cartesian coordinates, polar coordinates. In this way, for example, an imaging behavior of the sensors (e.g., by means of polar coordinates) can be adapted to the coordinate system used in an improved manner. In addition, a calculation of the cells in Cartesian coordinates is advantageously carried out with little effort.A further preferred embodiment of the occupancy map according to the invention is characterized in that areas of the cells are small in a near area of the vehicle and large in a far area of the vehicle. In this way, the cell sizes are better matched to driving situations at higher speed.A further preferred embodiment of the occupancy map is characterized in that the cells are adapted to the speed depending on a speed of the vehicle. This advantageously results in an embodiment of the occupancy map that is optimally adapted to the respective specific driving situation.A further preferred embodiment of the occupancy map according to the invention is characterized in that the cells are formed to be long and narrow at a high speed of the vehicle substantially in the direction of travel and to be short and wide at a low speed of the vehicle substantially in the direction of travel. This advantageously results in a configuration of the cells which is optimally adapted to a real driving situation.A further preferred embodiment of the occupancy map according to the invention is characterized in that areas of the cells are designed to be large at a high speed of the vehicle and small at a low speed of the vehicle. In an advantageous manner, an information requirement is thereby adapted to the driving situation depending on the driving situation, wherein it is taken into account that an information requirement from the occupancy map depends on the current speed situation of the vehicle.A further preferred embodiment of the occupancy map according to the invention provides that the cells are adapted to drivable maneuvers of the vehicle. In this way, a useful value of the occupancy map can be significantly increased, since unnecessary information in the form of environmental data is not acquired or generated at all.A further preferred embodiment of the occupancy map according to the invention is characterized in that the cells are adapted to a road profile for the vehicle. Due to the fact that a driving situation is also determined by a road profile, the occupancy map is thereby advantageously provided in a manner in which the vehicle can draw the best possible benefit from the occupancy map.A further preferred embodiment of the occupancy map according to the invention is characterized in that a number of cells of the occupancy map is constant. Advantageously, in this way, a computational or storage effort for determining the occupancy map remains essentially always constant independently of the adaptation processes and can thus be planned better.A further preferred embodiment of the occupancy map according to the invention is characterized in that the occupancy map has a high cell density in regions of interest dependent on the driving situation. As a result, a data supply of the occupancy map is focused on those areas in which there is an increased information requirement on account of the specific driving situation.An advantageous further development of the method according to the invention provides that a detection characteristic for a sensor device of the vehicle is ascertained from the occupancy map. As a result, in a development process of a sensor device, its detection characteristics or operating characteristics can be adapted to conditions in the vehicle on account of different driving states.The invention is described in detail below with further features and advantages on the basis of a plurality of figures. All features described or shown form the subject matter of the invention, either alone or in any combination, independently of their summary in the patent claims or their reference, and independently of their formulation or representation in the description or in the figures.The figures show: FIG. 1 shows a vehicle having a determination device for determining the occupancy map according to the invention; FIG. 2 ashows a conventional occupancy map for a vehicle in Cartesian coordinates; FIG. 2 bshows an embodiment of an occupancy map according to the invention for a vehicle in Cartesian coordinates; FIG. 3 ashows a conventional occupancy map for a vehicle in polar coordinates; FIG. 3 bshows a further embodiment of the occupancy map according to the invention for a vehicle in polar coordinates; FIG. 4 shows a further embodiment of the occupancy map according to the invention for a vehicle in Cartesian coordinates; FIG. 5 shows a further embodiment of the occupancy map according to the invention for a vehicle; FIG. 6 shows a further embodiment of the occupancy map according to the invention for a vehicle; and FIG. 7 shows a basic illustration of a sequence of an embodiment of the method according to the invention.Embodiments of the InventionFIG. 1 shows a schematic illustration of a vehicle F in which a determination device 200 for providing the occupancy map 100 according to the invention is arranged. A plurality of sensor devices S 1, S 2, S 3 known per se (e.g. radar sensor, ultrasonic sensor, wheel rotational speed sensor, camera, etc.) transmit their data of a vehicle environment to ascertainment device 200, which is provided for ascertaining occupancy map 100. The ascertainment device 200 can be provided as a separate electronic vehicle control unit or integrated into an already existing electronic control unit (e.g., an ACC control unit). By means of a return channel of the ascertainment device 200 to the individual sensor devices S 1, S 2, S 3, it can advantageously be provided that the occupancy map 100 created is used to modify a detection characteristic of the sensor devices S 1, S 2, S 3 in order to be optimally adapted to a driving situation of the vehicle F. Furthermore, the data mentioned can also be used for a configuration of a sensor configuration.FIG. 2 ashows a conventional occupancy map 100 with individual cells Z with fixed size and predefined geometry, wherein the cells Z are arranged in a Cartesian coordinate system. Each of the cells can assume, expressed in simplified terms, two different states ("occupied" or "free"), corresponding to a degree of trafficability of the respective cell Z. The states mentioned can additionally also be associated with a probability value. An arrow in the center of occupancy map 100 is intended to indicate a direction of travel R of vehicle F.According to the invention, it is provided that occupancy map 100 is adapted to the respectively current driving situation of vehicle F by a suitable configuration and arrangement of individual cells Z of occupancy map 100. For this purpose, it can be provided, for example, that in areas in which a high accuracy of a surroundings detection is required for a given driving situation, a larger number of cells Z of the occupancy map 100 is located, while fewer cells Z are used in so-called "non-interesting areas". This principle may be referred to as "attention control". Adjusting a cell size may depend on one or more of the following parameters: distance of an object, current speed, road shape, drivable maneuvers, etc.It can be seen in FIG. 2 b, in which a greater travel speed of the vehicle F than in FIG. 2 a, is assumed that the cells Z are now "pulled lengthwise" in the direction of travel of the vehicle F and "shortened" transversely to the direction of travel. As a result, during a faster journey, the preview width becomes greater, wherein for this purpose the underlying occupancy map 100 is drawn in length, i.e. stretched in the longitudinal direction and optionally compressed simultaneously in the transverse direction.Lateral dimensions of the cells Z are formed in the vicinity of the vehicle F (i.e. at a distance of approximately a few meters from the vehicle F), preferably approximately in the centimeter range, and in the far range of the vehicle (i.e. at a distance of an order of magnitude of approximately greater than 100 m from the vehicle F), preferably approximately in the meter range. That is, the cells Z may be formed to be "long and narrow" at a high vehicle speed, with a cell length preferably in a range of about 1 m to about 2 m and a cell width in a range of about 50 cm to about 1 m.In contrast, during slow driving (i.e. in driving situations in which a high maneuverability of the vehicle should be provided, for example in intersection areas, during parking, etc., for example at a speed between about 5 km / h and about 20 km / h), a high forward-view distance is generally not required, so that the configuration of the occupancy map 100 can be substantially "short and wide". This may result, for example, from a length dimension of the cells Z in a range from about 10 cm to about 30 cm and from a width dimension of the cells Z in a range from about 10 cm to about 30 cm. Alternatively, however, in this case expansions of the cells Z in the longitudinal and transverse direction can also be almost the same, which means that exemplary embodiments of the cells Z in the near range can preferably be in a range of approximately 10 cm x approximately 10 cm and in the far range in a range of approximately 1 m x approximately 1 m.This takes into account the fact that for the vehicle F at a high speed (e.g. when travelling on a country road or a freeway under good visibility and road conditions and moderate traffic volume without traffic congestion, i.e. in a speed range between approximately 80 km / h and approximately 160 km / h), a driving situation is present in which a side recognition accuracy is not particularly relevant, but a forward-view range or forward-view recognition accuracy should be designed to be large. It can also be seen that a total number of cells Z in the occupancy map 100 of FIG. 2 b, which is adapted according to the invention, has remained the same as the conventional occupancy map 100 of FIG. 2 a. This means that a computational or storage outlay for the creation of occupancy map 100 remains the same and is adapted or optimized according to the invention to the specific driving situation.The above numerical examples in connection with FIGS. 2 aand 2 b, for example the numerical examples for the short range, long range, cell width, cell length, speed ranges, generally and in particular apply to all embodiments disclosed in the description and are therefore not limited only to the embodiments described in connection with FIGS. 2 aand 2 b.FIG. 3 ashows a conventional occupancy map 100, the cells Z of which are arranged in polar coordinates. In FIG. 3 b, there is a greater travel speed of the vehicle F than in FIG. 3 a. It can be seen that the occupancy map 100 is now drawn in length, similar to FIG. 2 b, so that a type of elliptical coordinate system is produced, which is in turn extended in the direction of travel R and compressed transversely to the direction of travel R. In this way, a fast driving state of the vehicle F can be treated more meaningfully without having to operate a computing effort for detecting the environment transversely to the direction of travel of the vehicle F.FIG. 4 shows a further embodiment of the occupancy map 100 according to the invention. In this variant, it is provided that occupancy map 100 takes into account the speed of vehicle F and is adapted to a technically or physically drivable maneuver of vehicle F. In this way, an occupancy map 100 is created in a curved coordinate system with Cartesian coordinates, the curvatures of which are all the flatter the higher the speed of the vehicle F. This takes into account the fact that the vehicle environment laterally of the vehicle F frequently only needs to be known in the vicinity, since a movement in the transverse direction at high speed is hardly possible or provided in any case. In this case, the occupancy map 100 in the near area is "constricted" as it were depending on the speed.As the distance from the vehicle F increases, the resolution of the occupancy map 100 may also be varied, for example logarithmically (this means a high accuracy in the near range and a low accuracy in the distance) or inversely proportional to the distance (e.g. due to a sensor principle whose distance resolution is inversely proportional to the distance).FIG. 5 shows a further variant of an occupancy map 100 adapted to drivable maneuvers, this time in polar coordinates.FIG. 6 shows a further variant of the occupancy map 100 according to the invention, in which it is additionally provided that a road profile or a planned driving maneuver of the vehicle F can be included for determining a suitable geometric modeling of the occupancy map 100. If, for example, it is known that the vehicle F will immediately travel to the right on account of the road profile or on account of a planned turning maneuver, a higher accuracy can be provided in this target area. This can be achieved, for example, by arranging the cells Z along the planned maneuver or the course of the road.Instead of a two-dimensional occupancy map 100, the method according to the invention can also be applied to three-dimensional occupancy maps, wherein the accuracy can also be adapted to a height profile of the route, for example.FIG. 7 shows a basic sequence of an embodiment of the method according to the invention. In a first step 400, a driving situation of the vehicle F is ascertained by means of an ascertainment device 200.In a step 401, a configuration of occupancy map 100 is adapted as a function of the driving situation.In summary, the present invention achieves an improved description of a vehicle environment by adapting an occupancy map to a current driving state of the vehicle. Different information can be used to determine the driving state. Among other things, these may be one or more of the following information:current vehicle speed,restrictions on the possible vehicle movements on the basis of kinematics of the vehicle and maneuvers which can be carried out dynamically in terms of driving (e.g. Kingen circle),accuracy of the sensors used (e.g. more inaccurate measurements in distance),future road course, which is taken from a digital map, for example,regions of interest of the vehicle environment for a planned driving maneuver.A particular advantage of the present invention is considered to be that, compared to a conventional occupancy map with a fixed predefined cell size and arrangement, the occupancy map according to the invention always has a high accuracy only in regions of interest, which can significantly reduce a need for computing and memory. For example, a constant maximum number of cells (and thus a maximum storage outlay) can be predefined, wherein these cells are always distributed in such a way that the greatest density of the cells lies in the regions of interest. When optimum coverage of the detection region is achieved, the optimization according to the invention can even achieve a reduction in computing power.The occupancy map according to the invention can also be considered a method for describing a required accuracy of a surroundings detection, since it comprises models with which it is possible to determine for different driving situations in which areas a higher accuracy is required.Although the present invention has been described with reference to preferred embodiments, it is by no means limited thereto.The person skilled in the art will thus modify and combine the features accordingly without departing from the core of the invention.

Claims

Method for providing an occupancy map (100) for a vehicle (F), comprising the steps of: - determining a driving situation of the vehicle (F) by means of a determination device (200); and - adapting a configuration of the occupancy map (100) as a function of the driving situation, characterized bythe step of: - determining a detection characteristic for a sensor device (S1, S2, S3) of the vehicle (F) from the occupancy map (100).Occupancy map (100) for a vehicle (F), comprising a plurality of cells (Z) arranged in grid-like manner, characterized in that the cells (Z) of the occupancy map (100) are adapted to the driving situation according to the method according to claim 1 as a function of a driving situation of the vehicle (F).Occupancy map (100) according to claim 2, characterized in that the cells (Z) of the occupancy map (100) are arranged in one of the following coordinate systems: Cartesian coordinates, polar coordinates.Occupancy map (100) according to claim 2 or 3, characterized in that areas of the cells (Z) are small in a near area of the vehicle (F) and large in a far area of the vehicle (F).Occupancy map (100) according to any one of claims 2 to 4, characterized in that the cells (Z) are adapted to the speed depending on a speed of the vehicle (F).Occupancy map (100) according to one of claims 2 to 5, characterised in that the cells (Z) are formed to be substantially long and narrow in the direction of travel (R) at a high speed of the vehicle (F) and to be substantially short and wide in the direction of travel at a low speed of the vehicle (F).Occupancy map (100) according to any of claims 2 to 6, characterized in that areas of the cells (Z) are made large at a high speed of the vehicle (F) and small at a low speed of the vehicle (F).Occupancy map (100) according to any one of claims 2 to 7, characterized in that the cells (Z) are adapted to drivable maneuvers of the vehicle (F).Occupancy map (100) according to any of claims 2 to 8, characterized in that the cells (Z) are adapted to a road course for the vehicle (F).Occupancy map (100) according to any of claims 2 to 9, characterized in that a number of cells (Z) of the occupancy map (100) is constant.Occupancy map (100) according to one of claims 2 to 10, characterized in that the occupancy map has a large cell density in regions of interest dependent on the driving situation.Computer program product having program code means for carrying out the method according to Claim 1, when it runs on a processing device or is stored on a computer-readable data medium.

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