SIGNALING DEVICE AND METHOD FOR SIGNALING IDENTIFICATION DATA FROM A FIRST VEHICLE TO A FOLLOWING SECOND VEHICLE AND CORRESPONDING PLATOONING CONTROL SYSTEM

Abstract

 The invention is concerned with a signaling device (30) for signaling identification data (28) from a first vehicle (11) to a following second vehicle (12), wherein the device (30) comprises a light source arrangement (R) for sending out light signals (29) from the first vehicle (11) to the following second vehicle (12) and an electronic control unit (23) for controlling the light source arrangement (R) in accordance with the identification data (28). The invention is characterized in that the light source arrangement (R) comprises an arrangement of several spatially distributed light sources (41) and the control unit (23) is designed to signal predefined single bits (b) of the identification data (28) by means of a respective dedicated light source (41, 45) of the light source arrangement (R).

Description

[0001] The invention is concerned with a signaling device for signaling identification data of a first vehicle from that first vehicle to a following second vehicle. Such a signaling device may be needed in connection with the so called platooning that is the first vehicle and the second vehicle are driving in a coordinated manner wherein driving maneuvers of the first vehicle are automatically taken over or copied by the second vehicle. The invention also provides a platooning control system for coordinating the first vehicle and the second vehicle for driving these vehicles in a platoon.

[0002] A platooning control system with a signaling device is known from EP 0 762 364 B1. According to this prior art the signaling device is used for signaling identification data of a leading vehicle to a following second vehicle. Additionally, the same signaling device is used for transmitting maneuvering data or plantooning data for the described coordination of maneuvers of two vehicles while driving in a platoon. The signaling device comprises a light source that sends out the identification data as a serial stream of bits. In order to receive the fast changing light signal of the serial stream, a special light receiver is needed in the receiving vehicle. A video camera that is also used in the receiving vehicle for observing the leading vehicle cannot be used for receiving the fast changing light signal. This makes the known platooning control system technically complex.

[0003] It is an object of the present invention to provide a signaling device for transmitting identification data from a first vehicle to a second vehicle.

[0004] The object is achieved by the subject matter of the independent claims. Additional embodiments that provide further advantages are described in the dependent claims, the following description and the drawings.

[0005] The invention provides a signaling device for signaling identification data of a first vehicle from that first vehicle to a second vehicle that follows or drives directly behind the first vehicle. The signaling device comprises a light source arrangement for sending out light signals to the following vehicle, i.e. the second vehicle. The device also comprises an electronic control unit for controlling the light source arrangement in accordance with the identification data. Thus, the electronic control unit controls or switches the light source arrangement such that the light signals emitted by the light source arrangement carry the information describing the identification data.

[0006] In contrast to the prior art, the light source arrangement comprises an arrangement of several spatially distributed or spatially separated light sources. In other words, at least two or three or four or more than four light sources are provided for transmitting the identification data. These light sources are spatially distributed or separated, that is they can be seen as separate, independent light sources when seen from the point of view of the second vehicle. The control unit is designed to signal predefined single bits of the identification data by means of a respective dedicated light source of the light source arrangement. In other words, for the first bit and the second bit and so on, i.e. for each bit, of the identification data, one specific light source is used for signaling the information (0 or 1) of that respective bit (bit set or bit not set). For example, the respective light source can be turned on or activated, if the respective corresponding bit is set to 1, and the light source can be turned off or deactivated, if the respective bit is set to 0. Of course, 1 can also be signaled by a deactivated light source and accordingly 0 can be signaled by an activated light source. As the light sources are each dedicated to a specific bit, there is a predefined mapping for associating the each bit to a specific light source.

[0007] The invention comprises the advantage that the bits of the identification data are not sent out serially one after another which would demand a light receiver which could resolve the resulting fast changing light signal. In contrast, the invention provides several spatially distributed or separated light sources, each indicating the current state or information of a specific bit of the identification data. Thus, a camera of the second vehicle that takes an image or several images of the leading first vehicle will see the identification data as brightness information and/or color information of specific pixels of the at least one image taken by the camera. Thus, the identification data can be extracted from an image taken by a camera of the second vehicle. This requires less technical effort.

[0008] In one embodiment, the light sources are arranged in a row. In other words, the light sources form a line, which may be arranged, e.g., horizontally or vertically at the back of the first vehicle. Arranging the light sources in a row provides the advantage that the position of the light sources may be interpolated or guessed in a camera image, even if a light source is deactivated or turned off.

[0009] The deactivated state of a light source may comprise that the light source is turned off, i.e. emits no light. Alternatively, the deactivated state may comprise that the light source emits less light than in the activated state. This provides the advantage, that a deactivated light source may also be visible or detectable, e.g. in a camera image.

[0010] The invention also comprises embodiments that afford additional advantages.

[0011] In one embodiment, the identification data comprises more bits than the light source arrangement comprises light sources that are dedicated for sending the bits. The control unit is designed to group the bits of the identification data into frames or groups and to send each frame or group separately one after the other. For example, the light source arrangement might comprise four or eight lights dedicated for signaling the bits, wherein the number of bits contained in the identification data can be 8 or 16, respectively. This would require two frames for sending or signaling all the bits of the identification data. Using frames provides the advantage that the number of light sources provided in the light source arrangement is independent from the number of bits contained in the identification data.

[0012] In one embodiment the control unit is designed to control one or more than one of the light sources as a respective frame control light. In other words, the light source arrangement not only comprises light sources for signaling bits, but also at least one light source that is not used for signaling the bits, but rather for signaling when one frame ends and the next frame starts. In other words, by means of the at least one light source used as frame control light, different light signal patterns (activated or deactivated) are signaled with each frame control light for identifying consecutive frames. Thus, even if two sets or frames of bits happen to be identical in two successive frames, nevertheless, by means of the at least one frame control light a change between the two frames is signaled or discernable such that the two frames can be distinguished, even if the light sources dedicated for signaling the bits of the identification data do not change their state of activation (i.e. stay turned on or off) due to the possible identify of two successive frames.

[0013] The control unit can be designed to send out the identification data repeatedly, in other words, once a sending cycle for sending out the identification data is finished, the sending cycle can start again or can be repeated.

[0014] In one embodiment the control unit is designed to initiate or lead in the sending of the identification data by signaling an initial or starting frame with some or all of the light sources activated or turned on. In other words, the starting frame does not signal the identification data themselves, but announces the sending of the identification data. By turning on or activating some or all of the light sources, a following second vehicle may recognize the position of light source arrangements, for example on the basis of at least one camera image. The starting frame optically indicates the position and/or geometry of the light sources that the control unit intends to use for signaling the bits of the identification data. Preferably, at least those light sources dedicated for signaling the bits of the identification data are turned on such that their position can be detected or determined for example in a camera image of a camera.

[0015] In one embodiment each of the mentioned frames lasts at least 100 milliseconds or at least 500 milliseconds. Thus, it is guaranteed that each frame is visible throughout the duration of at least one video frame of a video camera. Such a video frame normally lasts 20 milliseconds. Thus, on the basis of a single camera image the respective activation state of each light source can be identified in a camera image, as no change of activation state of the light sources occurs during the recording of the image. No special light sensor additional to a camera is needed. Preferably, each frame is shorter than 10 seconds, preferably less than 5 seconds. Thus, a succession of several frame leads to a blinking effect of the light source arrangement. The light source arrangement can therefore be additionally used for signaling to other traffic participants that the first vehicle and the second vehicle are driving in a platooning mode.

[0016] In one embodiment those light sources of the light source arrangement that are dedicated to sending the bits of the identification data have a predefined opening angle of light radiation that is different from (i.e. smaller or larger than) the respective opening angle of at least one remaining light source of the light source arrangement. In other words, the light sources used for sending out or signaling the bits of the identification data emit their light with a different opening angle than at least one remaining light source of the light source arrangement. The difference regards the wideness or size of the opening angle, not a difference in orientation. From a predefined relative position, a traffic participants might either see only the light sources for sending the bits or the other way around only the lights of the at least one remaining light source. Thus, it can be prevented that traffic participants are irritated or disturbed by the signaling device. Additionally or alternatively, a different brightness of the light sources for sending the bits might be provided when these light sources are in the activated state as compared to at least one remaining light source of the light source arrangement in the activated state. In other words, the light sources used for signaling the information of the bits of the information data may have a different brightness in the activated state than the at least one remaining light source in the activated state. This can also be used for reducing the degree of irritation regarding other traffic participants and/or a driver of the following second vehicle. Likewise, different colors of light may be provided.

[0017] In one embodiment the light source arrangement is designed as two separate parts which are designed to be arranged on separate doors of a truck. Thus, the light source arrangement can be placed on the doors at the back of a truck without hindering or blocking the doors.

[0018] In one embodiment the light source arrangement comprises less than 30 light sources. Additionally or alternatively, a distance of neighboring light sources is larger than 5 centimeters for all light sources. This makes sure that in a camera image of a camera of the second vehicle the light sources can be distinguished or separated on the basis of the image data of the camera, if the distance between the second vehicle and the first vehicle is smaller than a maximum distance value (e.g. 100 meters or 50 meters) which is typical for platooning.

[0019] In one embodiment the light sources are designed to emit visible light, in particular yellow light. Thus, the light source arrangement can also be used for signaling the platooning mode of the first and the second vehicle to other traffic participants. In another embodiment, the light sources do not emit visible light, but rather only infrared light. Thus, the light signals of the light source arrangement will not irritate human drivers. In another embodiment the light source arrangement comprises a mix of different light sources, with some light sources for emitting visible light (i.e. a color from red to blue) and some other light sources for emitting only invisible light, e.g. infrared light. This allows for controlling which light sources will also signal information to human drivers.

[0020] As has already been described, the signaling device may be used as part of platooning control system.

[0021] The invention also provides such a platooning control system comprising an embodiment of the inventive signaling device and a computer vision device. The signaling device may be installed in a first, leading vehicle, wherein the computer vision device may be installed in a second vehicle following the first vehicle. The computer vision device comprises a camera which is sensible to the light signals of the light sources of the signaling device. The camera of the computer vision device is also designed to generate pixel-based images of the light sources. The computer vision devices comprises an image processing unit which is designed to detect an activity state of each of the light sources in at least one image of the camera. The image processing unit is also designed to reconstruct or recognize single bits of the identification data from the detected activity state of the light sources. In other words, the computer vision device may determine from at least one camera image which light source of the signaling device is activated and which is deactivated, e.g. turned on or turned off. As the light sources are associated with a specific bit of the identification data, this allows for determining the content or information (0 or 1) of each of the bits of the identification data. Thus, no separate light sensor, but a conventional camera may be used for transmitting the identification data from a first vehicle to a second vehicle.

[0022] In one embodiment the platooning control system comprises a radio communication unit for receiving platooning data from another vehicle. Such a radio communication unit may be based on the so called vehicle-to-vehicle communication technology. The radio communication unit may be based on WIFI-technology and/or Bluetooth technology and/or mobile communication technology (e.g. 5G). By means of the radio communication unit the platooning data may be transmitted. Such platooning data may comprise data regarding a maneuver planned or initiated by a leading vehicle of a platoon and/or by the first vehicle. The platooning data especially also comprises identification data of the vehicle that is sending out the platooning data and/or that is leading the platoon. A following second vehicle may receive the platooning data by means of the radio communication unit and therefore may therefore know or determine the next maneuver of the leading vehicle. However, the second, following vehicle cannot be sure simply from the platooning data themselves, whether the vehicle that is actually or physically driving in front of the second vehicle is that leading vehicle that also sent out the platooning data. Therefore, the platooning control system is designed to associate the platooning data to a vehicle carrying the described signaling device. This is done on the basis of the identification data detected in the at least one image of the camera of the computer vision device on one side and on the basis of the identification data contained in the platooning data on the other side. If they match, it is clear, that the platooning data received over the radio communication unit belong to the vehicle that is visible in the camera image. The use of radio communication provides the advantage that the actual platooning data can be transferred at a higher data rate than is possible by means of light signals. Additionally or alternatively, the transfer of the platooning data is more robust and/or weather conditions may influence the radio communication less than the transfer of light signals.

[0023] The operation of the platooning control system results in a method which is also part of the invention. The inventive method is for signaling identification data of a first vehicle from that first vehicle to a following second vehicle. As has already been described in connection with the signaling device, in the first vehicle a signaling device provides a light source arrangement for sending out a light signal to the following second vehicle and an electronic control unit controls the light source arrangement in accordance with the identification data. The light source arrangement provides a spatially distributed arrangement of several light sources and the control unit signals predefined single bits of the identification data by means of a respective dedicated light source of the light source arrangement.

[0024] Accordingly, in the second vehicle a computer vision device operates a camera which is sensible to light signals of the light sources of the signaling device and which is designed to generate pixel-based images of the light sources. An image processing unit of the computer vision device detects an activity state of each of the light sources in at least one image of the camera and reconstructs single bits of the identification data from the detective activity states of the light sources.

[0025] As has already been described, each frame of signal bits may last longer or may have a duration which is larger than the capturing time for a single camera image (which is usually 1/50 or 1/60 of a second). In other words, each frame of bits of the identification data may be visible in several successive camera images. Accordingly, in one embodiment the image processing unit detects an activity state of each of the light sources in several images that show a specific frame of bits. Then, the final reconstruction of the single bits of the identification data is done as a mean value and/or count value (i.e. a statistical evaluation) of the detective activity states as detected in the several images. Thus, even if in one single image an activity state is detected falsely, e.g. due to rain and/or a short interruption of the line of sight due to another traffic participant, the bits can be reconstructed correctly, for example if at least three images are evaluated. The computer vision device may group or identify images showing the same frame on the basis of the described light signal patterns emitted by the additional control lights. Such a light signal pattern may switch or change whenever the control unit switches from one frame to a successive frame. Thus, by the currently emitted signal pattern of the control lights it is visible whether still the same frame or the next frame is signaled.

[0026] The platooning control system may be installed in vehicles that may be designed for driving in a platoon, for example in trucks.

[0027] The invention also comprises the combinations of the features of the described embodiments.

[0028] In the following an exemplary implementation of the invention is described. The figures show:

Fig. 1

a schematic illustration of a platooning control system according to the invention;

Fig. 2

a signaling device operated according to an embodiment of the invention;

Fig. 3

a diagram illustration a timing schedule for sending several bytes of identification data;

Fig. 4

a schematic illustration of a side view of a signaling device which comprises light sources with different opening angles of light radiation.

[0029] The embodiment explained in the following is a preferred embodiment of the invention. However, in the embodiment, the described components of the embodiment each represent individual features of the invention which are to be considered independently of each other and which each develop the invention also independently of each other and thereby are also to be regarded as a component of the invention in individual manner or in another than the shown combination. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

[0030] In the figures elements that provide the same function are marked with identical reference signs.

[0031] Fig. 1 shows a top view of a driving scene 10 where two vehicles 11, 12 are driving as a platoon 13. The vehicles 11, 12 can be, for example, trucks. The vehicles 11, 12 may be driving on a track 14 of a road 15. For illustration purposes, a second track 16 is shown which may be used by a further vehicle 17, for example a passenger vehicle that is overtaking the platoon 13.

[0032] In platoon 13, vehicle 11 may be a leading or first vehicle V1 of the platoon 13. The first vehicle 11 need not be the front vehicle or very first vehicle of the platoon 13. The first vehicle 11 may be following another vehicle of the platoon 13 or it may be the front vehicle. Vehicle 12 may be a following or second vehicle V2 driving directly behind vehicle V1 in the order of the platoon 13.

[0033] While vehicles 11, 12 are driving in platoon 13, the second vehicle V2 may be driven or steered or conducted by an electronic control unit 18 such that the driver of the second vehicle may relax or concentrate on another activity than driving vehicle 12. For conducting vehicle 12, electronic control unit 18 may control a driving speed 19 and/or a steering 20 of vehicle 12 in dependence on the driving speed 21 and/or the steering 22 of vehicle 11. To this end, an electronic control unit 23 of vehicle 11 may signal platooning data 24 indicating the driving speed 21 and/or the steering 22 of vehicle 11 and/or a maneuver planned or executed by vehicle 11. The platooning data 24 may be signaled by means of radio communication unit 25 that may communicate with a corresponding radio communication unit 26 of vehicle 12 over a radio communication link 27, e.g. a Bluetooth-link and/or a WIFI-link and/or a mobile communication link, just to name examples. Control unit 18 may receive the platooning data 24 over the communication unit 26 and may then set the driving speed 19 and/or the steering 20 for vehicle 12. In this way, vehicle 12 may follow vehicle 11 autonomously or by means of an autonomous driving function of control unit 18 without a driver of vehicle 12 necessarily steering vehicle 12.

[0034] However, electronic control unit 18 must verify that the platooning data 24 received over the radio communication link 27 actually belong to vehicle 11 that is driving directly in front of vehicle 12. In other words, as the radio communication link 27 is invisible, it is not possible to verify that the platooning data 24 have been sent out by the leading vehicle 11. In order to verify the origin of the platooning data 24, the first vehicle or leading vehicle 11 (V1) may identify itself on the basis of identification data 28 which may be contained in the platooning data 24. Additionally, vehicle 11 may signal the identification data 28 as light signals 29 which may be emitted by a light source arrangement R of a signaling device 30. Light source arrangement R may be attached to a back side 31 of vehicle 11. Thus, vehicle 12 directly following vehicle 11 is able to capture image data 32 of the light source arrangement R by means of a video or still image camera 33. Camera 33 may be part of a computer vision device 34 that may also comprise an image processing module or image processing unit 35 that may be provided as a software module for, e.g., electronic control unit 18 or another electronic control unit (not shown). Thus, image processing unit 35 may recognize the identification data 28 in the light signals 29 on the basis of the image data 32. When receiving platooning data 24 that comprise identification data 28 and at the same time identifying the directly leading vehicle 11 as the vehicle that emits light signals 29 signaling the same identification data 28, the vehicle 12 may verify that the platooning data 24 received over the radio communication link 27 originate from the directly leading vehicle 11. Therefore, an electronic control unit 18 may decide that it is safe to set the vehicles speed 19 and/or the steering 20 for vehicle 12 according to the platooning data 24, as they match the directly leading vehicle 11 such that the platoon 13 is driving correctly.

[0035] In the same manner, vehicle 12 may also send its own platooning data to a following vehicle (not shown) and by means of an additional light source arrangement R', the same verification may be provided for the next vehicle.

[0036] The signaling device 30 and the computer vision device 34 together form a platooning control system 36.

[0037] As it is shown in Fig. 1, a driver of vehicle 17 may also see the signaling device 30. As the light signals 29 may be generated by blinking light sources (not shown in Fig. 1), the signaling device 30 may also function as a visual indicator to the driver of vehicle 17 that the two vehicles 11, 12 are driving in a platoon 13 such that the driver may avoid steering the vehicle 17 between the two vehicles 11, 12.

[0038] A field of view FOV of camera 33 is indicated in Fig. 1 by dashed lines. The back side 31 of leading vehicle 11 may be positioned inside the field of view FOV.

[0039] Fig. 2 illustrates a view onto the back side 31 of the first vehicle 11 as it might be seen from vehicle 12. For example, the view shown in Fig. 2 can be an image as represented by the image data 32 captured by camera 33 of the computer vision device 34. The signaling device 30 can be arranged in a bottom position at the back side 31 as shown in Fig. 2. Alternatively, the signaling device can be positioned at alternative positions 37, 38 higher than the position shown. The signaling device 30 can be provided as one single part as shown in Fig. 2 or in several different parts 39, for example two parts, for arranging the signaling device at doors 40 at the back side 31 of vehicle 11.

[0040] For generating the light signals 29 indicating or for signaling the identification data 28, the light source arrangement R of signaling device 30 may comprise several light sources 41 which may be arranged in a row, for example a horizontal row as shown in Fig. 2 or a vertical row (not shown). For the sake of clarity, only two light sources are provided with the corresponding reference sign for light sources 41.
The light sources 41 may be controlled by the control unit 23 of vehicle 11 or by another control unit (not shown). By means of the light sources 41 not all of the platooning data 24 need to be signaled. It may be sufficient to signal only the identification data 28. The identification data 28 may be sent repeatedly in signaling cycles.

[0041] Fig. 3 illustrates, how the light sources 41 of signaling device 30 may be switched between a deactivated state and an activated state for signaling the identification data 28. In Fig. 3, two possible activation states or activity states are illustrated, that is a deactivated state 42 and an activated state 43. The activity states are shown over the time t wherein for different time frames TF the activation state of each light source 41 is set individually. Each time frame TF may comprise an on-time or a lighting time TL and an off-time or a pause time TP. After each pause time TP, the next time frame TF starts with the lighting time TL. During the pause time TP, all light sources 41 may be in the deactivated state. During the lighting time TL, the activity state is set according to the specific meaning of the current time frame TF. For example, for signaling identification data 28, a signaling cycle 44 may start with a starting frame SF followed by four time frames signaling single bytes B0, B1, B2 of the identification data 28. The illustrated examples shows identification data 28 comprising 3 bytes. More or less bytes or another number of bits is possible.

[0042] Fig. 3 also illustrates, how the identification data 28 may signal an identification ID of vehicle 11 which may comprise the three bytes B0, B1, B2 wherein each byte B0, B1, B2 may comprise eight bits b with numbers 0 to 7 wherein the bits 0, 1, 2, 3 may constitute the least significant bits LSB and the bit 4, 5, 6, 7 may constitute the most significant bits MSB. For the sake of clarity, only bits 0, 1, 2 of byte B0 are indicated with a reference sign.

[0043] While signaling the bytes B0, B1, B2, the activity state of specific dedicated light sources 45 is set according to the corresponding content (0 or 1) of a specific bit of the identification data 28 as indicated in Fig. 3, wherein the association between light source 45 and the corresponding bit b is only exemplary. The cross hatch indicates that the activation state of the light source 45 in the specific time frame TF depends on the content of the associated bit b, i.e. whether the bit b is 0 or 1. Other light sources 41 may function as frame control lights 46 which change their activity state with the successive time frames TF such that with the change of time frames TF, a blinking effect is generated. The control lights 46 together form a light pattern for visually ideating when one frame ends and the next starts. The start frame SF may be an initial frame which optically indicates a respective position and/or geometry of the light sources 41, especially the dedicated light sources 45. To this end, all or most of the light sources may be in the activated state during the start frame SF. Some of the light sources 41 may be used as bound light sources 47 indicating the bounds or boundaries of the row of light source arrangement R. This may support the computer vision device 34 in recognizing the light source arrangement R in successive images generated or captured by camera 33.

[0044] Fig. 4 illustrates, how the different light sources 41 of signaling device 30 may provide different angles 48, 49. Some of the light sources 41 may provide an angle 48 that is narrower than the angle 49 of at least one other light source 41. For example, the wider angle 49 may be designed to present parts or some of the light signals 29 not only to camera 33, but also to a vehicle 17 passing by the platoon 13. For example, the control lights 46 which provide a blinking effect, may have an angle 49 such that the blinking effect is also visible from the passing by vehicle 17. The narrower angle 48 maybe adjusted in such a way that the camera 33 may receive the light signals 29 of the corresponding light sources 41 without at the same time being perceivable by a driver of a passing by vehicle 17. To this end, the height and/or orientation of the corresponding light sources 41 may be adjusted to the height of camera 33 of the same platooning control system 36. The light sources 41 may comprise the same or different light color and/or type of radiation (visible light, infrared, ultraviolet). They may be of the same color or of different colors.

[0045] Instead of identifying the leading or previous vehicle in a platoon 13 by reading its registration plate or a QR-Code on the vehicle's backside by a camera's image recognition, the leading vehicle actively emits light signals 29 by means of light sources 41 of a signaling device 30. This reduces the difficulty in detecting the signaling device as opposed to the detection of as small registration plate and its content on the backside of a truck due to the limited resolution of a camera as it may be provided in the second vehicle 12. Additionally, at low illuminance condition, it is not possible to get an image of adequate quality for recognizing a registration plate or a QR-Code.

[0046] The platooning control system 36 provides the possibility of identifying the leading or previous vehicle in a platoon 13 from a following vehicle 12 by means of a forward-looking camera 33 for ensuring that the identification data as received via vehicle-to-vehicle-communication as part of platooning data 24 belong to the vehicle 11 immediately in front of the vehicle 12.

[0047] The idea is based on the implementation of a light source arrangement R of light sources, for example LED lights (LED-light emitting diode), which emit blinking signal frames TF in a time sequence over time t that can be recognized or captured by following vehicles forward-looking camera 33 and can be analyzed by an image processing unit 35. By emitting several frames TF of light signals 29, a series of bytes B0, B1, B2 which sum up or represent the identification code or identification data 28 of the vehicle or its driver (depending on the use case). The identification data 28 may be provided in a control unit for performing the control of the platoon 13 and may be transferred to a control unit 23 for controlling the light source. These two functionalities may also be provided in one single control unit 23.

[0048] At the same time, the light sources 41 of the light source arrangement R may constitute a visual warning to other vehicles 17 as they generate blinking light signals 29 indicating that the vehicles 11, 12 of platoon 13 currently in a platooning formation, i.e. the distance between the two vehicles 11, 12 of platoon 13 (and further following vehicles) may be smaller than allowed for the case that the following vehicle is driven by a driver (manual driving). For both usage, yellow may be an appropriate color of the light sources 41.

[0049] The identification sequence resulting from the identification data 28 may consist of a starting frame SF (for example all light sources 41 turned on or activated except for example the most left and right light source 47-bounding light sources 47). Successive time frames TF may signal single bytes B0, B1, B2 with the bound light sources 47 activated, wherein controlling lights 46 may alternate their activity state from on to off with each time frame TF. Eight dedicated light sources 45 may be data light sources indicating the single bits B of the byte B0, B1, B2 that is to be transmitted. This example is valid for the case that eight dedicated light sources 45 as data light sources are available.

[0050] The purpose of the bounding light sources 47 can be the denoting of the total width of the light source arrangement R, while the controlling lights 46 (for example two of them just next to the bounding light sources 47 and one in the middle of the light source arrangement R) with their alternate turning on and off designating the time periods or frame periods of the single time frames TF.

[0051] The implementation of the light sources 41 is better visible even in night conditions compared to registration plates and/or printed QR-Codes, especially at distances larger 30 meters or 50 meters. The distance between single neighboring light sources 41 can be adapted to the camera resolution of the camera 33 belonging to the cartooning control system 36 such that two different light sources 41 in neighboring positions may still be resolved at a predefined given distance between the vehicles 11, 12.

[0052] The person skilled in the art may experiment with different light sources and light source arrangements and activation of single light sources during a time frame TF and with duration of the time frames TF. Additionally or alternatively, the light source arrangement R can be split up or separated into two halves or parts 39 (one per back door side of the back doors 40) and be mounted at a higher position (see Fig. 2) at the truck's rear side or back side 31.

[0053] Overall, the example shows how a system for the identification of a platooning vehicle is provided by the invention.

Claims

1. Signaling device (30) for signaling identification data (28) from a first vehicle (11) to a following second vehicle (12), wherein the device (30) comprises a light source arrangement (R) for sending out light signals (29) from the first vehicle (11) to the following second vehicle (12) and an electronic control unit (23) for controlling the light source arrangement (R) in accordance with the identification data (28), characterized in that the light source arrangement (R) comprises an arrangement of several spatially distributed light sources (41) and the control unit (23) is designed to signal predefined single bits (b) of the identification data (28) by means of a respective dedicated light source (41, 45) of the light source arrangement (R) .

2. Signaling device (30) according to claim 1, wherein the identification data (28) comprises more bits (b) than the light source arrangement (R) comprises dedicated light sources (41, 45) that are dedicated for signaling the bits (b) and wherein the control unit (23) is designed to group the bits (b) of the identification data (28) into frames (TF) and to send each frame (TF) separately one after the other.

3. Signaling device (30) according to claim 2, wherein the control unit (23) is designed to control one or more than one of the light sources (41) as a respective frame control light (46) by signaling alternating light signal patterns with each frame control light (46) for identifying consecutive frames (TF) .

4. Signaling device (30) according to any of the preceding claims, wherein the control unit (23) is designed to initiate the sending of the identification data (28) by signaling an starting frame (SF) with some or all of the light sources (41) activated, wherein the starting frame (SF) optically indicates a position and/or a geometry of the light sources (41) that the control unit (23) intends to use for signaling the bits (b) of the identification data (28).

5. Signaling device (30) according to any of claims 2 to 4, wherein each frame (TF) lasts at least 100 milliseconds or at least 500 milliseconds.

6. Signaling device (30) according to any of claims 2 to 5, wherein each frame (TF) lasts less than 10 seconds or less than 5 seconds.

7. Signaling device (30) according to any of the preceding claims, wherein the dedicated light sources (41, 45) for sending the bits (b) have a predefined opening angle (48) of light radiation that is different from the corresponding opening angle (49) of at least one remaining light source (41) of the light source arrangement (R) and/or a different brightness in the activated state (43) as compared to at least one remaining light source (41) of the light source arrangement (R) in the activated state (43).

8. Signaling device (30) according to any of the preceding claims, wherein the light source arrangement (R) is designed as two separate parts (39) which are designed to be arranged on separate doors (40) of a truck.

9. Signaling device (30) according to any of the preceding claims, wherein the light source arrangement (R) comprises less than 30 light sources (41) and/or a distance of neighboring light sources (41) is larger than 5 cm.

10. Signaling device (30) according to any of the preceding claims, wherein the light sources (41) are designed to emit visible light, in particular yellow light, or only infrared light or the light source arrangement (R) comprises a mix of different light sources (41), with some light sources (41) for emitting visible light and some other light sources (41) for emitting only invisible light.

11. Signaling device (30) according to any of the preceding claims, wherein the light sources (41) are arranged in a row.

12. Platooning control system (36) comprising a signaling device (30) according to any of the preceding claims and a computer vision device (34), wherein the computer vision device (34) comprises a camera (33) which is sensible to light signals (29) of light sources (41) of the signaling device (30) and which is designed to generate pixel-based images (32) of the light sources (41) and wherein the computer vision device (34) comprises an image processing unit (35) which is designed to detect an activity state (42, 43) of each of the light sources (41) in at least one of the images (32) of the camera (33) and to reconstruct single bits (b) of identification data (28) from the detected activity states (42, 43) of the light sources (41).

13. Platooning control system (36) according to claim 12, wherein the platooning control system (36) comprises a radio communication unit (26) for receiving platooning data (24) from another vehicle (11), wherein the platooning data (24) also comprise the identification data (28), and the platooning control system (36) is designed to associate the platooning data (24) to a vehicle (11) carrying the signaling device (30) on the basis of the identification data (28) detected in the at least one image (32) and on the basis of the identification data (28) contained in the platooning data (24).

14. Method for signaling identification data (28) of a first vehicle (11) from that first vehicle (11) to a following second vehicle (12), wherein in the first vehicle (11) a signaling device (30) provides a light source arrangement (R) for sending out light signals (29) to the following second vehicle (12) and an electronic control unit (23) controls the light source arrangement (R) in accordance with the identification data (28), characterized in that the light source arrangement (R) provides a spatially distributed arrangement of several light sources (41) and the control unit (23) signals predefined single bits (b) of the identification data (28) by means of a respective dedicated light source (41, 45) of the light source arrangement (R) and in the second vehicle (12) a computer vision device (34) operates a camera (33) which is sensible to the light signals (29) of the light sources (41) of the signaling device (30) and which is designed to generate pixel-based images (32) of the light sources (41), wherein an image processing unit (35) of the computer vision device (34) detects an activity state (42, 43) of each of the light sources (41) in at least one image (32) of the camera (33) and reconstructs the single bits (b) of the identification data (28) from the activity states (42, 43) of the light sources (41) as detected in the images (32).

15. Method according to claim 14, wherein the image processing unit (34) detects an activity state (42, 43) of each of the light sources (41) in several images (32) showing a specific frame (TF) of bits (b) and reconstructs the single bits (b) of the identification data (28) as a mean value of the respective activity states (42, 43) of the respective dedicated light source (41, 45) as detected in the several images (32).

Drawing