DE102020205805A1 - Procedure for transferring information during coordinated driving - Google Patents

Abstract

A method for the transmission of information during coordinated driving from a lead vehicle to a follower vehicle is proposed, the lead vehicle having a plurality of light sources which are set up to emit light independently of one another in order to emit a coded light signal in the direction of the follower vehicle and the follower vehicle a Has camera which is set up to detect the coded light signal. The method comprises the following steps: encoding the light signal with at least one planned driving state of the host vehicle by means of a spatial position of the respective light source and a temporally different light intensity of the respective light source; The host vehicle emitting the encoded light signal; Detecting the encoded light signal by the following vehicle; and decoding the encoded light signal by the following vehicle, for controlling a driving behavior of the following vehicle.

Description

State of the art

For "independent safe driving" of individual vehicles, the German road traffic regulations stipulate a minimum distance in Section 4.1 of the German Road Traffic Act, which must be so large that it is possible to stop behind a vehicle that suddenly brakes. The vehicle in front can act as a lead vehicle for a following vehicle, that is, communication takes place while driving one behind the other. The lead vehicle, through its driving behavior, specifies the speed and distance to be selected for the driver controlling the following vehicle or its controller, as long as driving behind one another takes place.

Many traffic rules are such that unidirectional communication from a lead vehicle or road user to at least one follower vehicle is sufficient, such as when a lead vehicle changes lanes into the lane in front of a follower vehicle at the same speed.

In other traffic situations, however, the mandatory mutual consideration also requires bidirectional communication. With such coordination between vehicles, a vehicle acts both as a sending lead vehicle and as a receiving follower vehicle. This requires appropriate communication with all road users who may be eligible for their own lane, that is, both with the vehicles in their own lane and with neighboring and / or oncoming or crossing vehicles and other road users.

Nowadays, the "communication" between vehicles, as described at the beginning, mostly takes place on the basis of driving behavior. A follower vehicle “reacts” to the driving behavior of the lead vehicle (s) relevant to it, that is, the action of a follower vehicle is the return response, i.e. re-action to the lead vehicle and the time required for the follower vehicle to act Reaction time.

The time allotted for this, or the set of rules derived from it, is now based on human abilities, that is, on their inertia. Accordingly, the traffic rules today are designed in such a way that the usual vehicle distances are accordingly very large in relation to the vehicle dimensions, which is why the traffic areas are only used to a relatively small extent even when there is a high volume of traffic. For example, at least 4 passenger cars would fit next to each other on a 3-lane motorway carriageway.

Nevertheless, especially when there is a misunderstanding in communication, traffic accidents occur again and again these days, with sometimes devastating consequences.

One of the communication media commonly used in road traffic is optical communication. For example, a changed driving behavior is indicated by means of brake lights. In addition to the classic switching on of the two lights on the outer vehicle contours while braking, there have already been further developments in recent years, such as the so-called third brake light and the adaptive brake light. In the case of adaptive brake lights, the lights flash at a rate of up to approx. 6 Hertz that can still be perceived by humans during heavy braking and / or the area of the lights and / or the light intensity is increased.

Modern motor vehicles are equipped with so-called LED lights. For example, the illuminated area of LED brake lights is composed of the emission of several light-emitter diodes (LED), which nowadays are switched on or off at the same time in the event of vehicle braking. In addition, the respective approval regulations for motor vehicles stipulate further lighting means, such as position lights, flashing lights and so on, which are to be used in each situation.

In the case of "closely coordinated safe driving", the vehicle in front is followed by one or more vehicles behind, preferably at a close distance, similar to the distance that is set with a drawbar between a towing vehicle and its trailer vehicle, for example at a speed of 90 km / h at a distance of less than 25 m, ideally less than 5 m.

For such coordinated, safe driving, vehicle-to-vehicle (V2V) communication must be reliably guaranteed. To this end, it is required that the communication between the vehicle in front and the vehicle behind it functions so reliably that coordinated driving is possible that corresponds to a mechanical tiller. This can only be achieved if the information exchanged is exchanged redundantly, reliably and immediately (i.e., in real time).

Such redundancy can be achieved by providing the information via different communication paths with different Technologies is transmitted in parallel, for example by transmitting the information on three different communication paths, so that, assuming that only one error occurs at a time, a faulty transmission can be recognized by the fact that the information transmitted on two paths is the same and one Deviation of a third way can thereby be identified.

However, the lights commonly used in road traffic today are only designed for communication with human drivers. They are limited to the transmission of less simple signs that can be perceived by humans and the rules are chosen in such a way that a follower vehicle only "re-acts" after a visible action by a lead vehicle. For example, the distance to leading vehicles driving ahead is currently measured by means of radar and only when this distance changes significantly does a following vehicle react accordingly to the changed driving behavior of the leading vehicle.

The use of images to represent the environment for at least partially automated mobile platforms is widespread, since images generally contain a lot of information. For this purpose, modern vehicles are equipped with cameras that analyze the image stream, known as video, from the surroundings in front of a vehicle and use it to control the vehicle. The controls mostly take on assistance tasks for the human driver, such as recognizing traffic signs, lane markings, lighting situations and so on.

Disclosure of the invention

Particularly when there is a high volume of traffic, it is desirable to use the limited available traffic area so intensively that this traffic can also be handled accident-free without congestion. "Dense, coordinated safe driving" is suitable for this. To make it easier to understand, the following explanations focus on driving in the same lane. In an equivalent way, however, they also apply to coordination with neighboring, following, crossing and / or oncoming road users.

An expansion of optical communication is necessary for closely coordinated safe driving because, on the one hand, a following vehicle requires additional information from the vehicle in front that is not yet available today and, on the other hand, the information flow, especially when driving at very close distances, must contain considerably more information.

It is characteristic of cameras, and in particular of vehicle cameras, that they record the luminous flux falling onto the camera from the environment by means of a matrix of optical sensor elements in defined time steps, the frames, and output them for processing. The values of the matrix elements are thus a measure of the luminous flux falling onto the camera from a certain spatial area during a time period. Frame durations customary today are tf = 30 ms and a typical size of such a matrix corresponds to approx. 1 Mpix and more. Thanks to the increasingly better local resolution options, modern cameras allow a spatial resolution that is considerably finer than that of the human eye. For example, modern cameras can resolve differences in brightness of objects 10 m away at a distance of less than 5 mm.

Vehicle lights, such as brake lights, reversing lights, etc. are typically activated in pairs at the same time. These lights can have a variety of light sources, such as LED rear lights, in which the light sources are typically switched on and off at the same time, with the exception of headlights and special direction indicators. The light sources of such lights, which are mostly arranged at a distance of less than 1 cm from one another, are no longer spatially distinguishable for the human eye from a greater distance. The lights then appear to the human eye like a coherent, larger, two-dimensional light source. With a control of full or. In partially automated vehicles, machine programs can implement a “driver's request” and driving behavior that occurs later can be announced, for example, by signals from the light sources of vehicle lights.

According to aspects of the invention, a method for transmitting information during coordinated driving, a device and a computer program according to the features of the independent claims are proposed. Advantageous configurations are the subject matter of the dependent claims and the description below.

In this entire description of the invention, the sequence of method steps is presented in such a way that the method is easy to understand. However, the person skilled in the art will recognize that many of the method steps can also be carried out in a different order and lead to the same result. In this sense, the sequence of the method steps can be changed accordingly and is thus also disclosed.

According to one aspect, a method for information transmission during coordinated driving from a lead vehicle to at least one follower vehicle is proposed, the lead vehicle having a plurality of light sources that are set up are to emit light independently of one another in order to emit a coded light signal in the direction of the following vehicle, and the following vehicle has a camera which is set up to detect the coded light signal. In a first step, the light signal is encoded with at least one planned driving state of the lead vehicle by means of a spatial position of the respective light source and a temporally different light intensity of the respective light source. In a further step, the coded light signal is emitted by the lead vehicle. In a further step, the coded light signal is detected by the following vehicle. In a further step, the coded light signal is decoded by the following vehicle in order to control the driving behavior of the following vehicle.

In the case of coordinated driving of a lead vehicle with a follower vehicle, the follower vehicle falls below a safety distance for individually driving vehicles and adjusts its driving status based on the light signals sent by the lead vehicle so that safe driving for both vehicles, for example with a significantly smaller safety distance, is guaranteed .

A plurality of light sources can comprise a small number of light sources, for example two or three light sources, the plurality can also comprise 100 light sources or an even higher number of light sources can be set up to emit light independently of one another.

A light signal can be encoded with a variety of methods, in particular the maximum brightness of a light source can indicate the state “on” or a state without emission of light the state “off”. In addition, at least one other state, for example with “half brightness”, can be used to encode signals by differentiating the light intensity of the light sources.

In addition to the light intensity, the coding can take place through the spatial position and / or the chronological sequence of the light states. In particular, a matrix of light sources can encode the signals spatially and / or temporally with different light intensities.

A coding with a number of different brightnesses or brightness levels can, for example, indicate a braking strength at which a brake light has different brightness depending on the braking strength when the brake is actuated.

In other words, from the point of view of the following vehicle K, light sources L1,. so that an image pattern is transmitted. The information to be transmitted can be transmitted by means of a duty cycle, a pulse repetition rate, a period or a frequency of light signals from at least one light source. These methods for the coded transmission of the information can also be combined with one another.

For such a coded transmission of information, an effect can be used that makes use of the fact that an asynchronously receiving light sensor can evaluate the end of the pulse relatively well, possibly as a half-time illuminated pixel of a camera, in order to transmit a larger number of information states by For example, the light source as the sender of the information also sends over fractions of the frame duration of the receiving camera and the receiving camera receives integrating precisely over the repetition duration of the periodic transmissions of the sender.

In particular, information about movement dynamics of the host vehicle can be transmitted in this way before it executes the movement in order to ensure safe driving during coordinated driving.

The movement dynamics include, in particular, acceleration, braking, or steering of the lead vehicle, but also instantaneous measured values such as slip, speed over the ground, or wheel speed, yaw, etc., up to and including the transmission of the trajectory that is being controlled shortly. The trajectory is all information useful for the following vehicle, in particular information about reaching the next stationary state, such as "stopping to a standstill" or "continuing at constant speed and unchanged steering for a long time that cannot be foreseen any further".

For detection, the following vehicle can capture a camera for capturing light sources, such as, in particular, a matrix of light sources with light-sensitive pixels, and thus generate a sequence of images.

For the transmission of information, it is particularly important for the following vehicle to receive a “driver's request” from the lead vehicle, which is transmitted to the following vehicle by coding the light sources. Thus, a plurality of light sources L1 (t), it is assumed that this driver's request describes driving behavior that actually occurs later.

As a result, the following vehicle A following the lead vehicle can control its longitudinal and / or transverse dynamics in accordance with the driving behavior of the lead vehicle almost synchronously and thereby ensure safe, coordinated driving. In particular, thanks to the simultaneous transmission of a large amount of information by means of several light sources, the actuators influencing the vehicle in the following vehicle can be controlled with a negligible delay, i.e. almost simultaneously, so that they move more or less synchronously with each other when braking, for example. Ideally, no relative change in distance is perceptible from the outside, i.e. they move towards each other as if they were connected to a virtual tiller.

Existing light sources, optionally arranged in a matrix form, can also be used as a matrix of light sources. For example, braking intentions can be transmitted in coded form with a brake light.

The encoded information transmission from the lead vehicle to the follower vehicle allows the follower vehicle to adjust its longitudinal and / or transverse dynamics almost synchronously in accordance with the driving behavior of the lead vehicle. By means of the described light signal, with a spatial position and temporally different light intensity, the information transmission can take place promptly and take place reliably and securely through redundant coding, in particular through spatial coding.

For example, the lead vehicle can have a rear wall made of a large number of lights as light sources, each light having an edge length of 5 × 5 cm ² . With a rear wall of the lead vehicle measuring 25 x 30 dm ^2, a light matrix of 50 x 60 pix = 3000 pix is created. If one also assumes that these lights are switched on or off in binary mode approximately every 0.1s, depending on the data to be transmitted, a data stream of 30000 pix / s = 30 kbit / s can be transmitted in this way . If the lights also differ in their color and in their light intensity, e.g. by switching 3 different colors on or off in binary form and in addition to the status "on" and "off" at least one more status "half brightness" is inserted, transmission rates in the Mbit / s range can be achieved.

For better detection, such an image matrix area can have a frame in order to be able to identify a reference in the form of the frame for the detection of the information during an evaluation. Such a frame can be implemented, for example, by means of a clear border and / or by means of specially agreed “frame” symbols, for example in accordance with a QR code (guick response code).

In practical terms, approximately 3 bits are sufficient to transmit the braking force, because deviations of> 10% are not unusual between the specified braking force and the braking force actually achieved.

As an alternative to a matrix of light sources, the lights (brake lights, direction indicators (flashing lights), side lights (parking lights), reversing lights, rear fog lights, etc.) that are customary in the context of the Road Traffic Licensing Regulations (STVZO) can be used for the transmission of information can be controlled or changed only insignificantly. In particular, a variation in the light intensity can be used for this purpose.

According to one aspect, it is proposed that the light signal is encoded with at least one planned and / or current driving state of the host vehicle.

The encoded information transmission of the planned and / or current driving status from the lead vehicle to the follower vehicle allows the follower vehicle to adjust its longitudinal and / or transverse dynamics almost synchronously in accordance with the driving behavior of the lead vehicle.

According to one aspect, it is proposed that the temporally different coding of the light intensity of the respective light source is carried out as a function of a temporal resolution capability of the camera of the following vehicle.

According to one aspect, it is proposed that the temporally different coding of the light intensity of the respective light source is coded with a minimum lighting duration which corresponds to at least twice a frame duration of the camera of the following vehicle.

By adapting the light intensity or lighting duration of the respective light source to the sensitivity or the resolution of the camera of the following vehicle, a particularly reliable and safe transmission of the information is guaranteed. In other words, this means that each light source is sufficiently constant for a duration of at least twice the frame duration, such as> 60 ms and in particular 3 times the frame duration, such as 90 ms, for example, For example, a lamp assumes the "on" or "off" status in order to be able to detect a clear signal by means of the camera.

According to one aspect, it is proposed that the light signal is encoded by means of a spatial position of the respective light source and temporally different light intensity of the respective light source so that a temporary total light intensity of the light sources and a resulting light area correspond to traffic-related specifications.

Thus, if information is mapped onto a pattern of light sources and the ensemble of the pattern, in particular with regard to the installation position, i. H. With regard to a light area, distances or a total light intensity, certain rules, traffic regulations or laws, such as the STVZO must be followed, the information can be mapped through the positions of satellite lights to a central light source with different duty cycles. For example, when braking, the brake light can consist of a central light with at least one satellite light arranged around it, which are coded in such a way that the corresponding rules, traffic regulations or laws are complied with.

In other words, the coding can be done in such a way that, if required by the regulations, a central light adjusts its light intensity depending on the light intensities of the currently switched on satellite lights in such a way that the sum of the light intensities of such a combination brake light complies with the regulations, i.e. is constant, for example.

LED lights with several light elements, as is known from at least one motor vehicle manufacturer, are suitable for mapping steering information. For example, a desired future direction of travel is indicated by classic synchronous simultaneous flashing of all light sources of a lamp and as soon as a steering movement is started, a light gap begins to run through in the "on" phases when flashing or a small one-pulse in the "off" phases to run through, the steering information (angle) being mapped to the speed of movement and / or width of the light gap and / or the one-pulse and / or the frequency or phase of the classic blinking.

According to one aspect, it is proposed that at least a subset of the plurality of light sources is set up to emit different light colors and the light signal is encoded by means of the emission of the different light colors of the respective light source.

Coding with different colors can transmit a wider variety of information or can be used for redundant transmission of information. For example, the basic colors red, green and / or blue, which are spectrally independent of one another, can be used. In the color red, for example, different information can be sent than in the colors green and / or blue. Alternatively, a larger light spectrum, such as, on the one hand, the mixed spectrum of brightness referred to as 'white', and on the other hand, a narrower spectrum, such as red, can also be varied at the same time as a “color” in such a way that different information from one and the same is varied Position to be sent out.

According to one aspect, it is proposed that the planned and / or current driving state of the host vehicle is coded for the light signal by means of a non-linear mapping.

A non-linear mapping of the values, for example a braking strength, to the information states to be transmitted advantageously results in the relative quantization error resulting from the digitization remaining of the same order of magnitude. This means that even small steering angles and weak braking can be transmitted with sufficient accuracy.

According to one aspect, it is proposed that the lead vehicle encodes the planned and / or current driving state of the lead vehicle in such a way that the following vehicle can recognize and / or recognize and correct transmission errors in the decoded light signal.

For this purpose, so-called block codes or other error-recognizing codes can be used and serious errors, for example relating to a sign of an acceleration, can be avoided. Transmission errors can also be detected through redundant transmission, which is transmitted via both the right and left halves of a vehicle rear wall, for example. This results in a robust and reliable transmission of information. In addition, coding that corrects errors, such as convolutional codes or redundant transmissions, can also be used, which enable the following vehicle, for example, to detect the correct information without interrupting communication or the driving status.

According to one aspect, it is proposed that the emitted light signal of the plurality of light sources is transmitted redundantly.
Such a redundant transmission can correct errors as well as detect errors and make the transmission of information more robust and reliable. Since errors in the transmission of the longitudinal acceleration can have very serious consequences, the use of error-detecting coding is also recommended.

Since the optical transmission of the light signals can be disturbed by environmental effects such as sun rays or large shadows, redundant transmission is suitable, for example via both the right and left halves of e.g. a vehicle rear wall.

In addition, if possible, a coding should be avoided in which simple errors, such as in particular in the sign, result in serious errors in the amplitude. For this purpose, block codes can be used in which such serious jumps in the amplitude errors due to simple bit errors are avoided, as well as other methods that are used from Internet data transmission or from the coding of a CD (compact disc).

According to one aspect, it is proposed that the light signal is encoded in such a way that a position of other light sources of the plurality of light sources by the following vehicle can be determined by means of a light pattern of at least one light source of the plurality of light sources.

For example, such a coding can be done in such a way that a lamp or light source L1,..

According to one aspect, it is proposed that, for information transmission during coordinated driving, information is additionally transmitted by sound transmission and / or electromagnetic waves between the lead vehicle and the follower vehicle and / or from the follower vehicle to the lead vehicle.

Through these additional technical transmission paths, information between the lead vehicle and the follower vehicle can be carried out additionally or redundantly.

According to one aspect, it is proposed that a second subset of the plurality of light sources is coded with different light intensities as a function of a distance between the lead vehicle and the follower vehicle.

In particular, light sources that are located on the outer edge of the contour of a vehicle can disturb other road users. With this modified method, the information can be reliably transmitted from the lead vehicle to the following vehicle, in which other road users can no longer be disturbed by the cover at a smaller distance, but the information is reliably transmitted.

For example, such a change can be made in such a way that the lights on the outer contour of the lead vehicle light up only at small distances so that approaching people cannot be dazzled because they are covered by the following vehicle at a small distance. The information about the distance can be transmitted to the lead vehicle by a variety of technical means.

According to one aspect, it is proposed that, based on the light signal, a control signal for controlling an at least partially automated vehicle is provided and / or that a warning signal for warning a vehicle occupant is provided based on the first and / or the light signal.

For example, the following vehicle can thereby be controlled by the lead vehicle. In the case of partially automated driving, for example, the driver of the following vehicle can be informed about traffic situations.

A device is proposed which is set up to carry out a method as described above. With such a device it is easy to transfer the method from one vehicle to another vehicle.

A computer program is specified which comprises instructions which, when the program is executed by a computer, cause the computer to carry out one of the methods described above. Such a computer program enables the described method to be used in different systems.

A machine-readable storage medium is specified on which the computer program described above is stored.

The methods described can in particular be used for operating at least partially automated mobile platforms. A mobile platform can be understood to mean an at least partially automated system which is mobile and / or a driver assistance system of a vehicle. An example can be an at least partially automated vehicle or a vehicle with a driver assistance system. That is, in this context, an at least partially automated system includes one mobile platform in relation to an at least partially automated functionality, but a mobile platform also includes vehicles and other mobile machines including driver assistance systems. Further examples of mobile platforms can be driver assistance systems with several sensors, mobile multi-sensor robots such as robotic vacuum cleaners or lawn mowers, a multi-sensor monitoring system, a production machine, a personal assistant, a ship, an aircraft, a shuttle, a robotaxi, commercial vehicles or an access control system . Each of these systems can be a fully or partially automated system.

Embodiments

In a first example of the method, two trucks drive at approximately the same speed of 90 km / h one behind the other at a distance of approx. 5 m on a motorway. Compared to the current regulation, in which the trucks have to drive a minimum distance of 50 m from each other, this results in a saving of 95%!

The front of the following vehicle can be equipped with a camera in the middle, which captures the traffic area between its front up to a height of approx. 2 m from the rear of the truck driving ahead and acting as the leading vehicle. In particular, this camera can use a shutter that is synchronous over the entire imager, with which a new image is recorded in synchronous time and fed to the decoding, preferably at very short time intervals, for example with a frame duration of 10 ms.

Between coding in the lead vehicle and decoding in the following vehicle, the communication-related significance of the light sources located at different positions with regard to the time behavior of the light intensity and / or color can be agreed in advance on the basis of preliminary agreements that were fixed, for example, by means of a computer program.

Via a further communication channel not explained in detail here, such as via a digital radio link, the control of the lead vehicle is known that in particular the middle to the outer area of its lights arranged in the rear of its semitrailer or trailer are covered in this way by the closely following truck that only vehicles driving directly past can see these lights.

The transmissions, in particular optical signals, of the lead vehicle can optionally vary depending on whether and, if so, how far away a following vehicle is. Since cameras are angle-measuring sensors, their spatial resolution increases as the distance from the object to be imaged decreases.

While the following vehicle is approaching the lead vehicle, the following vehicle can preferably receive the characteristic data characterizing the lead vehicle, such as, for example, the mechanical geometry data, acceleration and braking capabilities, coefficients of friction and so on. Based on this information, the following vehicle can approach the lead vehicle in the manner described above.

For example, this information can be varied on the basis of the brightness modulation of the rear license plate lights using a white light spectrum at a relatively slow transmission speed, as long as there is still no vehicle following the lead vehicle at a closer distance. However, after the lead vehicle is followed by a follower vehicle at a closer distance of, for example, less than 20 m, the lead vehicle varies the light signals from the same position in a different color spectrum, such as green, for example with a significantly higher transmission speed and, for example, with more detailed information about its characteristics.

As long as two trucks drive one behind the other at almost stationary speed, the lead vehicle controls its rear lights in accordance with the applicable lighting regulations. In addition, it controls in particular the lights hidden by the closely following follower vehicle, such as the license plate lights of the lead vehicle, in such a way that the follower vehicle can at least verify the functionality of the optical communication to the lead vehicle.

For example, some light sources serve as spatial orientation symbols for the optical synchronization of the image sequence, on the basis of which the decoding of the camera images takes place, which are blurred as a result of the relative movement of the following vehicle camera to the lead vehicle.

For example, some light sources are used to verify the optical communication channel, such as temporal data synchronization and / or verification of an address, i.e. that communication actually takes place with the communication partner who corresponds to the object assumed in the communication model of the following vehicle.

The lead vehicle is optionally set up, in addition to its planned driving state, such as the time behavior of path points in its future trajectory, preferably by means of the following vehicle for the surrounding area To transmit light sources covered by traffic, so that the following vehicle can always fine-tune its driving behavior in order to keep the desired distance, closely coordinated, always safe.

For example, thanks to spatially separated light sources, for example in three or more different areas, the optical communication from the lead vehicle to the follower vehicle can always be checked for transmission errors, and thanks to the extensive redundancy, various errors, such as brief obscuration by dirt, can also be detected and corrected .

For example, the following vehicle can be equipped with at least one additional camera which is offset from the first camera and which, for example, also detects the coded light signal emitted by the lead vehicle independently of the other cameras and decodes its information content.

The reliability of the communication can be verified in such a way that if the quality deteriorates, the following vehicle, for example, reacts immediately by increasing the distance.

If, for example, the following vehicle is followed by another vehicle in a comparable manner, this vehicle following the first leading vehicle can serve its successor in an equivalent manner as a further leading vehicle, i.e. it can communicate its planned and optional driving status according to the invention in the same way. Coordinated safe driving can therefore, for example, also contain multiple communications / coordination with a large number of vehicles and road users alike.

If, for example, the lead vehicle now has to brake hard, for example due to an obstacle suddenly standing in front of the lead vehicle, and at the same time perform a violent evasive movement, the lead vehicle transmits its planned new driving state according to the invention by the lead vehicle, in accordance with the previously made agreements, the corresponding light sources to transmit this Event activated.

In a further aspect, this takes place simultaneously using a large number of spatially offset light sources so that the information to be transmitted in this way can be transmitted in a very short time, for example within twice the shutter time (frame duration) at the latest, that is, for example can be detected by the camera sensor surface within 20 ms.

Thanks to the at least quasi-simultaneous transmission and parallel decoding of the light signals sent by the lead vehicle, the information sent by the lead vehicle can be available in less than 30 ms to control the actuators in the follower vehicle. In the case of trucks in particular, their actuators usually have a control delay of sometimes more than 300 ms, so that with the transmission method described here, the control delay in the lead vehicle and the follower vehicle is negligible. In addition, the influence of the transmission delay can be largely compensated for with a correspondingly changed control of the actuator in the following vehicle that takes this into account. For example, in the event of braking, the brake actuator of the following vehicle can be controlled more strongly than the actuator in the lead vehicle until both vehicles brake synchronously again.

In addition to the simultaneous transmission of the information within a very short time, such as within less than 100 ms, for example by switching light sources on or off, information can be emitted and detected by means of controlled brightness fluctuations, color changes, frequency and / or phase changes of the signal source will.

According to one aspect, the light sources and cameras of vehicles directed to the side and forward for communication can also be used. For example, a car drives on the middle lane of a 3-lane motorway at around 144 km / h. He acts with his light signals the following vehicle following him in approx. 8 m at approximately the same speed in the same lane, like a lead vehicle already described in an equivalent manner, in order to transmit at least his planned driving status in this way. At the height of the gap between these two vehicles, two other cars are driving at roughly the same speed in both the left and right lanes. In this example, the car driving on the left of the gap in the left lane signals a request to change into the gap by means of its right-hand direction indicator, while at the same time the car on the right lane signals a wish to change into the same space by means of its left-hand indicator.

For example, both the vehicle in the left lane and the vehicle in the right lane are each equipped with a side camera as well as a slightly front and rear facing camera in such a way that these vehicles can not only detect each other and their side light signals, but also the light signals of the Front of the rear car and the rear of the front car in the middle lane.

Since for the rear car in the middle lane not only the car driving ahead in its lane but also both cars to the side of the gap in front of it are decisive for its driving, all these cars are equally lead vehicles for it.

For such situations, for example, if the vehicle's request to change in the left lane has priority over the vehicle's request to change in the right lane, the vehicle in the right-hand lane signals, for example by means of changed emissions from its light sources, that it complies with the request to change the lane on the left has noticed and accepted moving cars.

For example, a direction indicator shown as a flashing signal can change its flashing frequency and / or, for example, the ratio of the on duration to the off duration during a flashing period. Alternatively, the on-duration could also be interrupted for a fraction of time by a time that is not perceptible to humans but is perceptible to the detecting camera and / or the light intensity could change. Alternatively, its light intensity can be changed during the longer on-duration of the flashing signal, for example it can fluctuate rapidly periodically.

According to one aspect, a waiting vehicle located to the side of the other vehicle can communicate its driving decision to the vehicle giving priority with a changed ratio of on-duration to off-duration of its flashing signal. A slight change, for example by the duration of a shutter speed of a camera, that is to say by a frame duration, can be precisely perceived without this being clearly visible to a human observer.

In this example, however, the on-duration is even changed to 2 / 5ths and accordingly the off-duration to 3 / 5ths, without, however, alternatively switching off the direction indicator completely. On the one hand, the direction indicator of the vehicle giving priority to the right-hand lane should also remain switched on so that a person can see it, as long as a change request remains, so to speak, as a target trajectory, and on the other hand, the proposed change in the blinking behavior, which is even perceptible to the attentive human observer, is intended the decision is also visible to human observers.

For example, equivalent to the decision of the car in the right lane, the car willing to change in the left lane could also signal to all those involved in the communication by changing the on-off ratio of its flashing signal that it has made the decision of the car in the right lane using its camera has detected and accepted. In this way, the car in the left lane would carry out a coordination with the car in the right lane in an optically bidirectional manner, before their decision can be perceived on the basis of their driving behavior.

According to a further aspect, the rear car in the middle lane can detect the decision of its two lead vehicles away from its lane by means of its camera. In an exemplary ideal case, this also confirms the voting result and the transmission of the left-hand car, which now changes into the narrow gap to the lead vehicle driving ahead in the same lane, is confirmed by means of previously agreed light symbols. For example, the following vehicle that gives priority, for example by means of less clearly previously agreed light signals, such as very short pulses of some LEDs from its headlights in the direction of the vehicle receiving priority, can also confirm to it that it will adapt its driving behavior accordingly to the change in the left-hand vehicle that now follows.

In a further preferred embodiment, the car driving ahead in the middle lane also detects the change requests, announced by means of light signals, of the cars driving behind it by means of its camera directed into the reversing area ("reversing camera"). In this situation, the vehicle in front is the following vehicle and follows the side vehicles behind it, which act as the lead vehicle.

With the exemplary use of the flashing lights that are already common nowadays and the described further development of their signaling, corresponding interoperability becomes possible, that is, the signaling changes barely noticeably for a human observer, but in such a way that information transmission and detection according to the invention can already be detected by means of a camera. It is foreseeable that both the temporal and spatial resolution capabilities of cameras will become significantly more sensitive in the next few years than a person can perceive. In complex and / or time-critical situations in particular, human perception tends to focus on what has been shown to be essential and to fade out other information.

With the procedure described, the coordination in the above case study takes place considerably faster than is usual and possible today. After 3 flashing cycles at the latest, ie after approx. 3 s, all vehicles would be coordinated with one another. Typically today it takes many seconds until, for example, the driver of the car on the right has switched off his indicator again and the driver of the car on the left has noticed this. The car following the gap in the middle lane can nowadays only safely signal this as confirmation that it accepts the change request by slowing down its speed to such an extent that the gap becomes larger. Signaling with a headlight flasher, on the other hand, can lead to misunderstandings and then to accidents.

Such security-related communication can be combined with further protection, such as additional communication via digital radio media.

Compared to radio media, which require a great deal of effort to ensure that the addressed receiver and transmitter actually correspond to the objects used in the respective environment model, the optical method according to the invention provides “addressing” thanks to direction-sensitive detectors with a very high level of reliability Realizable with little effort.

In a further example situation, two vehicles designed according to the invention come towards each other, for example at a bottleneck. In the coordination required for this, both act according to the invention as the lead vehicle and the follower vehicle.

After both vehicles have exchanged their driving requests in a first communication, for example via the signaling according to the invention and / or via alternative media, such as radio communication, and have determined the conflict between the driving requests, there is a not explained here Decision-making process that is carried out, for example, based on consideration based on the vehicle identification data and / or based on cost reimbursements instead. The enormous benefit of this method according to the invention becomes clear at the latest during the subsequent mutual signaling of the coordinated, changed driving requests. Especially when there are a large number of other vehicles in the same traffic area, the precise spatial resolution of the cameras means that the position, i.e. the “address” of a sender, can be detected with high accuracy. In particular with direction-sensitive light sources, as they are already used today in modern headlights, the emission of the light signals can also be addressed relatively precisely.

In an exemplary embodiment, a light, such as a brake light, for example, consists of 32 LED light sources, which are arranged next to one another in such a way that the light appears like a uniformly shining body.

According to one aspect, for information transmission, at least one light source is varied at least in terms of its light intensity as a function of the information to be transmitted. For example, the brightness of one of the 32 LEDs fluctuates for a period of 2 frames, that is, for example for 60 ms. Such a short, small fluctuation is hardly perceived by the human eye, at least from a great distance, while a modern camera with its high and fast signal dynamics can detect this fluctuation.

Furthermore, the lamp can be set up in such a way that at least one of the light sources that are adjacent to the aforementioned information-dependent fluctuating LED allows its brightness to fluctuate information-dependently in the opposite direction to the aforementioned LED, for example in such a way that temporarily, i.e. in this time segment, the The total light intensity of the luminaire remains unchanged.

The information contained in the image is preferably decoded in several stages by first determining the position of the vehicle and / or the light still located on it based on the information obtained in at least one previously detected image, and then determining the position in an at least further step Information is decoded, the mapping of the information not only in the brightness fluctuation, but also in its time of occurrence, in the type and / or duration of the fluctuation and / or in the position on the vehicle and / or the lamp and / or in the emitted light spectrum can.

In addition, the same or a different piece of information can be transmitted in a corresponding manner at a different position of the same lamp or at a different point in the vehicle, possibly simultaneously or possibly redundantly at a different point in time.

• 1 eine Abbildung einer Information auf ein Bit-Muster;
• 2 eine Abbildung unterschiedlicher Zustände auf volle Vielfache von 3 Frames;
• 3 eine Abbildung unterschiedlicher Zustände auf Teile von Vielfachen von 3 Frames;
• 4 eine Abbildung unterschiedlicher Zustände auf Teile von Vielfachen von 3 Frames;
• 5 eine alternative Abbildung unterschiedlicher Zustände mit unterschiedlichen Pausendauern; und
• 6 eine Abbildung unterschiedlicher Zustände mit gleichem Ein-zu-Aus-Verhältnis.

Further embodiments of the invention are described with reference to FIGS 1 until 6th and explained in more detail below. It shows:

• 1 a mapping of information onto a bit pattern;
• 2 a mapping of different states to full multiples of 3 frames;
• 3 a mapping of different states to parts of multiples of 3 frames;
• 4th a mapping of different states to parts of multiples of 3 frames;
• 5 an alternative mapping of different states with different pause durations; and
• 6th an illustration of different states with the same on-to-off ratio.

the 1 sketches one of many possible mappings of information on a bit pattern, the values, such as a braking strength B, being defined non-linearly on the digital information states A. It can thereby be achieved that the relative quantization error resulting from this digitization remains of the same order of magnitude regardless of the signal level. For example, 8 states of a 3-bit binary word A can be mapped ^{to a braking force B between 0 and 10 m / s 2.} For example, to transmit values of an acceleration of a vehicle, ie when accelerating, at least one further bit position can be provided in order to encode the sign of the acceleration. Since the amounts are typically not as high in the case of positive acceleration as in the case of negative acceleration, ie braking, the mapping, ie coding, of the values used can take place as shown above, but a different slope can be selected so that the achievable values are finer are resolved.

The following figures show by way of example how information can be encoded onto binary light signals. The time is displayed horizontally in the unit of measurement “number of frame durations”. Different states are shown vertically. “1” means that the light signal is emitted in the time required to code the corresponding status. Otherwise there will be no emission.

the 2 outlines a mapping of information to a pulse duty factor, ie a period duration, a lamp, or in the case of redundant transmission to a pair of lamps, with eight different states on full multiples of two frames, each having a duration of approx. 60 ms, for example.

Correspondingly coded information can be determined by integrating a sensor signal over 7 * 2 frame durations = 420 ms. This can be sufficient, for example, to transmit small steering angles or weak braking.

the 3 sketches an illustration of also 8 different states but this time as multiples of a frame.

With this figure, the 2 The amount of information shown can be transmitted in a shorter time, ie in approx. 270 ms, by utilizing the effect that an asynchronously receiving light sensor can evaluate the end of a pulse relatively well, possibly as a half-time illuminated pixel. From the 3 it can be seen that state 6 is clearly differentiated from state 7, in that the 2-frame long pause can be safely evaluated by an asynchronously receiving sensor, such as a light sensor.

the 4th outlines an illustration with the same repetition rate of 420 ms as that of 2 using the in 3 coding method shown. Thanks to the in 3 The mapping method shown in 2 The repetition rate used can now even be mapped to 13 different states.

The sending system can also send in a non-integer multiple of the time grid shown horizontally, as long as each luminaire is relatively constant for a period of at least twice the frame duration, e.g.> 60ms, ie the "on" or "off" status of a luminaire.

With the procedures described that go with the 2 until 4th have been explained, it is possible to transmit a larger number of information states, even if the detecting light sensor were received asynchronously and only over a fraction of the frame duration. In the case of camera technologies with the so-called “rolling shutter” that are widespread today, such asynchronicity must be expected. However, if the shutter were to be synchronized with the emitting light source, the transmission rate could even be doubled.

In the 5a and 5b further illustrations are sketched which have different time intervals of pauses for coding the information. From the comparison of the 5a and 5b it becomes clear that a different amount of time is required for a transmission of the information, depending on the selected image, which is definitely justifiable for certain information, such as light braking. In the 5a, b the information is displayed with different resolutions for the duration of the "off" time. The mean value or the repetition rate varies depending on this.

the 6th sketches a figure that appears particularly robust with regard to correct transmission, since the time from switched on light source to switched off light source is identical, that is, the mean value is 50%. In other words, this means that this transmission is particularly robust because the information is mapped via the frequency and the same on-off status is very immune to interference from external light. This results in a correspondingly relatively low transmission speed.

Claims (15)

Method for information transmission during coordinated driving from a lead vehicle to at least one follower vehicle, the lead vehicle having a plurality of light sources which are set up to emit light independently of one another in order to emit a coded light signal in the direction of the follower vehicle; and the following vehicle has a camera which is set up to detect the coded light signal, with the steps: Coding of the light signal with at least one planned driving state of the host vehicle by means of a spatial position of the respective light source and a temporally different light intensity of the respective light source; The host vehicle emitting the encoded light signal; Detecting the encoded light signal by the following vehicle; and Decoding of the coded light signal by the following vehicle to control a driving behavior of the following vehicle. Procedure according to Claim 1 , wherein the light signal is encoded with at least one current and / or planned driving state of the host vehicle. Method according to one of the preceding claims, wherein the temporally different coding of the light intensity of the respective light source is carried out as a function of a temporal resolution of the camera of the following vehicle. Procedure according to Claim 3 , the temporally different coding of the light intensity of the respective light source being coded with a minimum lighting duration which corresponds to at least twice the frame duration of the camera of the following vehicle. Method according to one of the preceding claims, wherein the light signal is coded by means of a spatial position of the respective light source and temporally different light intensity of the respective light source so that a temporary total light intensity of the light sources and a resulting light area correspond to traffic specifications. Method according to one of the preceding claims, wherein at least a subset of the plurality of light sources is set up to emit different light colors and the light signal is coded by means of the emission of the different light colors of the respective light source. Method according to one of the preceding claims, wherein the planned and / or current driving state of the host vehicle is coded for the light signal by means of a non-linear mapping. Method according to one of the preceding claims, wherein the lead vehicle encodes the planned and / or current driving state of the lead vehicle in such a way that the following vehicle can recognize and / or recognize and correct transmission errors in the decoded light signal. Method according to one of the preceding claims, wherein the emitted light signal of the plurality of light sources is transmitted redundantly. Method according to one of the preceding claims, wherein the light signal is encoded in such a way that a position of other light sources of the plurality of light sources by the following vehicle can be determined by means of a light pattern of at least one light source of the plurality of light sources. Method according to one of the preceding claims, wherein for information transmission during coordinated driving, information is additionally transmitted by sound transmission and / or electromagnetic waves between the lead vehicle and the follower vehicle and / or from the follower vehicle to the lead vehicle. Method according to one of the preceding claims, wherein a second subset of the plurality of light sources is encoded with different light intensities as a function of a distance between the lead vehicle and the follower vehicle. Method according to one of the preceding claims, wherein, based on the light signal, a control signal for controlling an at least partially automated vehicle is provided; and / or a warning signal for warning a vehicle occupant is provided based on the first and / or the light signal. Device which is set up, a method according to one of the Claims 1 until 12th perform. Computer program, comprising instructions which cause the computer program to be executed by a computer, the method according to one of the Claims 1 until 12th to execute.

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