GB2524162A

GB2524162A - Method for transmitting an environment model

Info

Publication number: GB2524162A
Application number: GB1501989.6A
Authority: GB
Inventors: Philipp Lehner; Holger Mielenz; Christian Heigele
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2014-02-07
Filing date: 2015-02-06
Publication date: 2015-09-16
Anticipated expiration: 2035-02-06
Also published as: FR3017482B1; GB2524162B; FR3017482A1; DE102014202313A1; GB201501989D0

Abstract

Method for transmitting environment model 10, 11, where first station 2 (e.g. vehicle) requests environment model 10, 11 from second station 3 (e.g. vehicle), where environment model 10, 11 is made of tiles 4 and describes the environment around the stations 2, 3 (vehicles). Tile resolution is also requested. Resolution selection may depend on the distance between the environment being requested and the requesting station (vehicle), or on available storage capacity. First station 2 may plan a path, the environment model comprising all tiles 4 on the planned route. A first set of low resolution tiles may be requested initially, to be replaced later by high resolution tiles. Resolution steps may differ by integral multiples. Tiles 4 may contain many cells 7, each cell 7 having occupancy probability. Tiles 4 may be GridTiles. The environment model may be created by environment sensors on the stations / vehicles.

Description

Description Title

Method for transmitting an environment model

Prior art

The present invention relates to a method for transmitting an environment model. The invention further relates to a vehicle by which such a method can be carried out.

Driver assistance systems of vehicles use environment information which they generally obtain and collect via appropriate environment sensors. In order to form an environment model from the environment information, the prior art knows occupancy grids, which represent an environment of the vehicle as a two-dimensional grid, the grid cells of which each contain information about whether the region of the environment represented by the grid cell can be driven on or is occupied by an obstacle, i.e. capnot be driven on. Generally, this is implemented by appropriate probability values for an occupancy of the cell. However, occupancy grids are very inflexible, since once a model has been created it cannot be extended. If the model is to be enlarged, a new model must be created and the original model integrated into the new model. The management of occupancy grids is thus very computationally intensive.

The prior art knows further possibilities for creating environment models. These include, inter alia, GridTiles.

GridTiles are mostly square tiles which store neighbourhood information about neighbouring GridTiles. With the aid of the neighbourhood information, models can be very simply extended, since new GridTiles are merely inserted at unoccupied neighbourhoods.

GridTiles here do not have to be tiles of square shape, but may also take other shapes.

If a plurality of vehicles are travelling in the same regions, each vehicle must create the environment model for the region itself. This is disadvantageous in particular for those regions which are frequented by many vehicles.

These include, for example, car parks or multi-storey car parks.

Disclosure of the invention

The method according to the invention allows a transmission of environment models between a first station and a second station. Collected information can thus be made available to other traffic participants. In order to be able to use an appropriate communication channel efficiently, according to the invention the size of the data to be transmitted is limited by variably selecting a resolution of tiles from which the environment model is formed. For transmission of the environment model, a first station requests the environment model from a second station. When requesting the environment model, furthermore a resolution of the individual tiles of the environment model is selected by the first station. Thus, the first station decides on the quality of the environment model to be transmitted, the first station setting the quality based on its own requirements, in particular based on requirements of its own assistance systems, which require environment information of different quality. The tiles here represent locally limited regions of the environment. A shape of the tiles is arbitrarily selectable, the tiles preferably being square. The environment iS, in particular, an environment of the first station and/or an environment of the second station.

The subclaims show preferred developments of the invention.

The resolution of the tiles is preferably selected in dependence on a distance of the regions of the environment, which are represented by the tiles, from the first station.

Thus, regions which are far away have a low resolution, while near regions have a high resolution. Thus, comprehensive information is available to the first station, so that, in particular, precise navigation as well as general planning of a movement path, along which the first station is to move, are possible.

Alternatively or additionally, the resolution of the tiles is selected in dependence on a storage capacity available in the first station. Thus, in particular, it is provided that for manoeuvres which require large areas all the tiles required therefor are requested, a resolution of the tiles being adapted to available storage resources.

Furthermore, it is preferably provided that the first station carries out a path planning, the environment model comprising all the tiles which are located along a planned path. For a path planning, in particular a low resolution is selected for the tiles.

If more precise information is required for regions for which tiles of low resolution already exist, preferably the tiles are requested again. For this purpose, preferably a first set of tiles is initially requested with a low resolution. At a later point in time at which, in particular, more precise information is required, the tiles from the first set are finally requested with a high resolution. It is thus made possible, in particular, for more precise information to be made available when it is ascertained during a path planning that it is necessary to travel through a narrow place. As a result of the narrow place, however, the path cannot be planned safely, so that the danger of a collision cannot be excluded. In this case, the relevant tiles for the narrow place are requested again with high resolution.

Advantageously, it is furthermore provided that a large number of resolution steps are predefined, the resolution steps differing by integral multiples. This simplifies, in particular, a transfer of information with a first resolution step to information with a second resolution step. Thus, tiles which represent the same region of the environment, but which have different resolutions, can be simply and efficiently combined.

Preferably, the tiles comprise a large number of cells.

Each of the cells comprises an occupancy probability, which, in particular, indicates whether the region of the environment represented by the respective cell is free or occupied. Preferably, it is furthermore provided that each tile has an integral number of cells. The resolution of a tile is defined, in particular, by the number of cells within a tile.

Advantageously, it is provided that the tiles are GridTiles. These allow a simple and flexible formation of environment models.

The invention further relates to a vehicle which comprises at least one control device. The above-described method can be preferably implemented by the vehicle. In particular, the method can be implemented on the control device of the vehicle. The vehicle corresponds here either to the first station or the second station.

Preferably, the vehicle according to the invention has environment sensors, by which a current environment of the vehicle is detectable. Thus, based on the data, at least one region of the environment model can be created. The data obtained by the environment sensors can be advantageously used for different assistance systems of the vehicle. Such assistance systems are, in particular, parking assistance systems or manoeuvring assistance systems. The method according to the invention makes it possible for the vehicle to increase the data of the environment sensors by the transmission of the environment model from a further station. Detailed information about the environment is thus available to the vehicle.

Brief description of the drawings

Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of an exemplary environment, Figure 2 is a schematic illustration of a first environment model of the environment from Figure 1, Figure 3 is a schematic illustration of a second environment model, which is transmitted by the method according to the invention according to an exemplary embodiment, Figure 4 is a schematic illustration of a third environment model, which is formed from the first environment model and the second environment model, after the transmission of the second environment model by the method according to the invention according to the exemplary embodiment, and Figure 5 is a schematic illustration of a vehicle according to an exemplary embodiment of the invention Exemplary embodiments of the invention Figure 1 shows an environment 5, the environment 5 comprising a large number of obstacles 14. The obstacles 14 are, in particular, parked vehicles and the environment 5 shows, in particular, a car park.

A first station 2 and a second station 3 are travelling through the environment 5 along a first roadway 12 and a second roadway 13. Both the first station 2 and the second station 3 are vehicles. In particular, the first station 2 and the second station 3 are each a vehicle 8 according to an exemplary embodiment of the invention, which is shown in Figure 5.

The vehicle 8 according to an exemplary embodiment of the invention comprises environment sensors 9, by which the environment 5 is detectable. The vehicle 8 thus has environment information at its disposal. The vehicle 8 is set up to transmit the environment information by the method according to the invention according to an exemplary embodiment. In this way, the vehicle 8 makes its own environment information available to other participants, while the vehicle 8 likewise has environment information made available to it by other participants.

The first station 2 therefore detects the environment 5 and creates a first environment model 10. This is shown in Figure 2. The first environment model 10 is limited by a detection range of the sensors of the first station 2. In the example shown in Figure 2, the first environment model comprises a single tile 4, which is preferably a GridTile. The resolution of the tile 4 is low, since the first station 2 has, for example, only low free storage capacities.

The first environment model 10 thus shows obstacles 14 and free spaces 15 very roughly. Moreover, owing to its limited extent, the first environment model 10 does not allow path planning, since only information about near regions of the environment 5 is available, as well as information along the first roadway 12. In particular, it is not possible either to plan a path which leads the first station 2 to the second station 3.

The second station 3 has already been moved along the second roadway 13 through the environment 5 and has therefore already detected and stored large parts of the environment 5. This is shown in Figure 3.

Figure 3 shows a second environment model 1, which is transmitted according to an exemplary embodiment of the method according to the invention. The second environment model 1 was created by the second station 3 as the latter was moved along the second roadway 13. Thus, the second environment model 1 show, analogously to the first environment model 10, obstacles 14 and free spaces 15 of the environment 5. Owing to the large extent of the second environment model 1, two tiles 4, in particular GridTiles, were used for modelling.

It can be seen from Figures 2 and 3, that the first environment model 10 of the first station 2 and the second environment model 1 of the second station 3 overlap, since the tile 4 of the first environment model 10 shows the same region of the environment 5 as the lower tile 4 of the second environment model 1. Only in its resolution does the tile 4 of the first environment model 10 differ from the tiles 4 of the second environment model 1.

The resolution of the tiles 4 is determined by cells 7. The cells 7 subdivide each tile 4 and have probability values which indicate whether the region of the environment 5 represented by the cell 7 is free. In the figures, different probability values are shown by different hatching.

In the first environment model 10, the tile 4 comprises a small number of cells 7, so that the cells 7 have large dimensions. The tile 4 is thus of low resolution. In contrast to this, the tiles 4 of the second environment model 1 have a large number of cells 7. The tiles 4 of the second environment model 1 are thus of high resolution.

In order to extend the first environment model 10 of the first station 2, the first station 2 requests the second environment model 1 from the second station 3. Since the first station 2 has merely a roughly resolved first environment model 10, the first station 2 requests the tiles of the second environment model 1 in the same rough resolution. The corresponding data is then transmitted from the second station 3 to the first station 2.

The first station 2 thus creates a third environment model 11, which combines the information of the first environment model 10 with the new information of the second environment model 1. In particular, the first environment model 10 is extended for this purpose. With the third environment model 11, a detailed model of the environment 5 is therefore available. The third environment model 11 thus allows the first station 2, in particular, also to plan a path to regions into which the first station 2 has not yet been moved and which therefore have not yet been detected by the first station 2 itself.

Overall, the third environment model 11 thus enables the first station 2 to precisely plan a path within the environment 5. If the first station 2 ascertains that, owing to narrow places, more precise information is required, the first station 2 again requests the second environment model 1, or individual tiles 4 of the second environment model 1, from the second station 3 with a higher resolution.

It is also advantageous if the first station 2 transmits the third environment model 11 created to the second station 3. The extended third environment model 11 is thus available to both stations.