Patent Description:
Commercial vehicle combinations, consisting of a towing vehicle and one or more trailers, face a number of safety-related issues due to their relative size in comparison to other vehicles, and due to the increased number of degrees of freedom resulting from the combination of several rigid components. In consequence, most driving tasks require a different handling for different types of trailers and load.

Several automated systems supporting a driver with determining the presence of a trailer, its type, load, and condition, as well as in various maneuvers have been proposed. One example for such a support consists in the determination of a tractrix, i.e. a curve or envelope of curves along which a trailer moves when pulled by a towing vehicle. For this kind of support, <CIT>) discloses a method for assisting a driver of a vehicle-trailer combination when driving along a curve, involving a detection of a lane and a predetermination of a reference lane for drawing the vehicle in such a way that the tractrix curve lies within the lane or is centered on the lane. A further example is provided by <CIT>, which discloses a method for warning a driver of a towing vehicle with trailer before a collision with a stationary obstacle on a driving route with curve. This includes sending a signal and/or carrying out an intervention if a wheel of the vehicle approaches the obstacle. Yet another example may be found in <CIT>, disclosing a method for warning a driver of a vehicle if there is a mobile object in the vicinity, or for anticipating a driving path of the vehicle if the object is stationary, followed by a warning of the driver if the object is determined to be located on the driving path.

<CIT> discloses an apparatus and a method for determining a spatial alignment of a semitrailer or trailer by using sensor data from pre-existing sensors on a towing vehicle, in particular from sensors e.g. from a blind-angle monitoring device, whose sensor data may be employed to measure angles which describe an alignment of the (semi-)trailer relative to the towing vehicle. The system may in particular be configured to prevent jack-knifing, or snaking above a threshold.

Automated systems designed for appropriately taking account of a trailer usually involve dedicated sensors on the vehicle, and so far generically assume a presence of a driver. With the advent of autonomous driving, high safety standards require an automatic and precise system performance for the corresponding task. A towing vehicle with a driving automation system should be able to effectuate driving tasks automatically for a variety of different trailers and loads. Advantageously, however, the system should only require a minimum of additional equipment on the vehicle.

For these reasons there is a demand for a system which which enables a towing vehicle to perform automatic driving tasks safely for a variety of trailers and loads.

At least to some extent, this is achieved by a system of claim <NUM>, a towing vehicle of claim <NUM>, a method according to claim <NUM>, and a computer product according to claim <NUM>. The dependent claims refer to further advantageous realizations of the subject matter of the independent claims.

The present invention relates to a safety system for a vehicle combination with a towing vehicle (like a tractor or truck) and a trailer, wherein the towing vehicle comprises a plurality of sensors configured to provide sensor data about an environment of the vehicle combination, or a state of the trailing vehicle. The system comprises a data collection module for collecting the sensor data, an extraction module for extracting, from the sensor data, information about a presence of the trailer or about a state of the trailer, and a control module, configured to control, based on the information, at least one driving task, or to provide the information to a further towing vehicle component in order to increase the safety of the vehicle combination.

The sensors on the towing vehicle may in particular be part of an autonomous driving system, i.e. hardware and software on board the towing vehicle that are collectively capable of performing part or all of a plurality of dynamic driving tasks for the towing vehicle on a sustained basis. In particular, the autonomous system may include back-facing exteroceptive sensors, as e.g. mirror replacement sensors.

The state of the trailer encompasses its characteristics (i.e. its geometry, or its type), and/or its current condition (i.e. a pose, an articulation angle between towing vehicle and trailer, or the trailer integrity). Providing the information to a further towing vehicle component may include sending the information, or a warning signal, to a driver.

The system may be configured as a supplement for an existing autonomous driving system. The data collection module is configured to tap the sensor data of the existing autonomous driving system.

The data collection module, extraction module, and control module may be embodied as separate devices, but they may also be partially or fully integrated into each other. Also, embodiments may stipulate that particular functions disclosed hereafter as performed by one module may in fact be performed by another one.

Optionally, especially if the towing vehicle is adapted to attach a semi-trailer, the plurality of sensors comprises at least one wheel speed sensor for measuring a wheel speed of a wheel of the towing vehicle, and the extraction module is configured to extract the information about the presence of the trailer based on an estimate of wheel slips from the sensor data of the at least one wheel speed sensor.

Especially if the truck is towing a semi-trailer, as in a case of a long-haul commercial vehicle, the axle load of the rear axle changes significantly when the trailer is connected to the vehicle. If the axle load changes, this has an effect on a rate or form of slips of a wheel. This can in particular lead to sudden changes in the wheel speed. The extraction module may be configured to estimate a number or form of wheel slips from the data of the wheel speed sensors of the wheels. Including data from wheel speed sensors of more than one wheel of the towing vehicle, especially at different axles, advantageously increases a reliability of the information.

Optionally the plurality of sensors comprises a sensor configured to detect a drive torque of an engine of the towing vehicle, the towing vehicle comprises an accelerometer for measuring an acceleration of the towing vehicle, and the extraction module is configured to extract the information about the presence of the trailer by a comparison of the acceleration of the towing vehicle with the drive torque provided by the engine.

The drive torque of the engine will depend on an acceleration of the vehicle, and on its mass. The extraction module may be configured to determine the mass of the vehicle, at least in relative terms, from the drive torque and the acceleration, and attribute additional mass, or mass exceeding that of the towing vehicle alone, to a trailer. This data may in particular be fused with the wheel slip data. For example, if the engine torque required to achieve the same acceleration increases, this may be used to validate a change in the wheel slips, and thus to corroborate the result of the two individual pieces of information.

Optionally, the plurality of sensors comprises at least one exteroceptive sensor (a sensor sensing an environment of the towing vehicle), configured such that a trailer attached to the towing vehicle is within a field of view of the exteroceptive sensor, and the data collection module is configured to collect the sensor data from the exteroceptive sensor.

Sensor data from exteroceptive sensors is obviously particularly advantageous for the task of the system. Based on data from such sensors, placed on an autonomous truck (with trailer interface), the extraction module may then easily determine the presence and other geometrical data (height, length, width, articulation angle) of the trailer. This information can be used either to support the driver of the towing vehicle, or to fully automate the driving process. Information from exteroceptive sensors on the towing vehicle is especially important as not all trailers are equipped with a CAN-communication interface. However, even in cases where a CAN-communication interface is present, the CAN data may be validated or corroborated by means of the sensors data of the exteroceptive sensors on the towing vehicle. Furthermore, the extraction module may be configured to determine a type of the trailer by truck perception sensors like e. g mirror replacement cameras. The trailer type is crucial, as different driving styles are required for each type of trailer.

Suitable for this task are any exteroceptive sensors on the towing vehicle which will have the trailer in their field of view. Particular examples include cameras sensitive to the visible spectrum, as e.g. mirror replacement cameras, cameras sensitive to the near infrared spectrum, sensors with direct distance information / time-of-flight sensors (e. g lidar or radar devices), or a calibrated stereo camera pair.

The estimation of the trailer characteristics from data of exteroceptive sensors may be fused, partially or fully, in order to obtain a more robust estimation. The extraction module and/or the control module may also be configured to validate or corroborate data from sensors with the trailer present in the field (e.g. in a case of big articulation angles), or check their operation.

The control module is configured to determine blind spots of the exteroceptive sensors, and to control at least one automated or assisted driving task based on the determined blind spot.

An exteroceptive sensor on the towing vehicle often has a specific blind spot, i.e. directions in its field of view where the line of sight is obstructed e.g. by geometric features of the towing vehicle. This blind spot may develop or increase if a trailer is in the field of view of the sensor. As the articulation angle of the trailer changes during the operation of the vehicle, the location of blind spots caused by the trailer will change accordingly. In addition, a laden trailer may cause a different blind spot from an unladen trailer, due to the cargo carried by the trailer. Thus, the load status of a trailer also affects the blind spots. The control module is configured to determine blind spots caused or increased by the trailer to particular perception sensors.

With regard to blind spots, the control module may in particular be configured to perform one or more of the following tasks: The effective field of view of a sensor may be verified. This may occur in a situation in which an object is detected by a sensor, but due to a change in the articulation angle should no longer be visible to the sensor (i.e., covered by the trailer). If the object is however still detected by the sensor, even though it is covered by the trailer, either the trailer articulation angle is not correctly identified, or the object detection sensor is malfunctioning. The control module may be configured to determine such a situation, and to send a corresponding information to a driver or to a location remote from the vehicle (as e.g. a workshop).

The control module may further be configured to identify false alarms of an environment perception (or object detection) sensor. It may be configured to identify false alarms only if the sensor is in fact supposed to have a part of its field of view covered by the trailer.

Furthermore, when fusing data from multiple sensors the control module may be configured to apply a higher-level logic, by taking into account that an object is not visible by a sensor only because the trailer is reducing the field of view of that sensor. This is particularly advantageous to take care of blind spots only caused at certain articulation angles. By knowing the blind spots caused by the trailer, the sensor fusion logic may be configured to remember an object in the proximity of the vehicle currently invisible due to blind spots caused by the trailer.

Optionally, the control module is configured to access information about a regular trailer state, and to detect in the state of the trailer an irregularity by a comparison with the information about the regular trailer state.

Data from perception sensors, e.g. camera-based detectors like mirror replacement cameras, thermal cameras, or lidar devices that have the ego truck and/or the trailer in their field of view can be used to detect irregular ego vehicle states. Such irregularities may in particular include broken parts of vehicle, open doors, malfunctioning lights, issues with tires, or any other vehicle conditions that deviate from a reference situation.

Optionally the control module is configured to detect one or more irregularities out of the following: An abnormal trailer articulation angle, an abnormal trailer horizontal angle, a trailer open (e.g. through an open door), a trailer accessory irregularity (as e.g. irregularly switched-off lights), a wheel irregularity, a cargo irregularity, a fire, and/or damage.

Wheel irregluarities may in particular include a situation where a wheel is lifted although settings stipulate that this should not be the case, a situation where a wheel is not lifted but according to the settings it should be, a flat tire, a burning tire, a burning cover, and/or overheating wheels. Burning and overheating may in particular be detected from thermal-range cameras.

Optionally, if the automated driving tasks include planning of a vehicle trajectory, the control module is further configured to receive the planned vehicle trajectory, and to determine, based on the information about a presence or a state of the trailer, a tractrix of the trailer for the planned trajectory.

If a presence of a trailer and its geometric data (like height, length, width, articulation angle) is determined, these data may be used to determine the tractrix of the truck-trailer vehicle combination according to one or more planned trajectories. This can be done for various truck-trailer combinations. The type of the trailer could be determined from sensor data and/or a classification of the trailer, which may serve as a further input for the tractrix calculation.

Optionally, the control module is further configured to communicate by wireless communication the information about the presence of the trailer or the state of the trailer to a system remote from the vehicle.

The communication could e.g. employ a vehicle-to-everything infrastructure to communicate to a workshop, or to a control center.

Embodiments further refer to a towing vehicle for attaching a trailer, in particular an autonomous vehicle, with a plurality of sensors configured to collect sensor data for automated or assisted driving tasks, characterized by a safety system as described above. The system may be configured as a supplement to a driving automation system of the towing vehicle.

The present invention further relates to a method for increasing a safety of a vehicle combination with a towing vehicle and a trailer, the towing vehicle comprising a plurality of sensors configured to provide sensor data about an environment or state of the vehicle combination. The method comprises the steps:.

This method may also be implemented in software or a computer program product and the order of steps may not be important to achieve the desired effect. Embodiments of the present invention can, in particular, be implemented by software or a software module in an electronic control unit. Therefore, embodiments relate also to a computer product with a program code for performing the method when the computer program is executed on a processor.

Advantages of a safety system and of the method as described above in particular include solutions to the following four trailer-specific problems, which are particularly relevant to commercial vehicles:.

All solutions rely only on the existing environment perception sensor cluster. None of these solutions require an installation of additional sensors or hardware on the towing vehicle.

Some examples of the systems and methods will be described in the following by way of examples only, and with respect to the accompanying figures, in which:.

<FIG> shows a schematic representation of a vehicle combination <NUM> with a towing vehicle <NUM> and a trailer <NUM>. The towing vehicle <NUM> comprises a plurality of sensors <NUM>, configured to provide sensor data about an environment of the vehicle combination or a state of the towing vehicle for an automatic driving task, effectuated in the figure by a module <NUM>. The towing vehicle <NUM> also comprises a safety system <NUM>, with a data collection module <NUM> for collecting the sensor data, an extraction module <NUM> for extracting, from the sensor data, information about a presence of the trailer <NUM> or about a state of the trailer <NUM>, and a control module <NUM>, configured to control, based on the extracted information, at least one driving task (or module <NUM>), or to provide the information to a further component of the towing vehicle <NUM>, which may include a driver, in order to increase the safety of the vehicle combination <NUM>.

The modules <NUM>, <NUM>, <NUM> of the safety system <NUM> may be partially or fully integrated into each other, and they may also be integrated into existing devices as e.g. specific electronic control units on board the towing vehicle <NUM>.

<FIG> illustrates the different strains on axles of the towing vehicle <NUM> due to a semi-trailer <NUM>. The trailer <NUM> exerts additional pressure on the rear axle, such that a force F<NUM> on wheels of the rear axle is greater than a force F<NUM> on wheels of the front axle. This results in different rates and forms of wheel slips, both when comparing the situation where there is no trailer <NUM> to the situation where a trailer <NUM> is present, as well as between wheels of the front axle compared to wheels of the rear axle in the situation where the trailer <NUM> is present. The weight is furthermore different for an empty trailer compared to a trailer with cargo, and the extraction system may be configured to extract an information on the weight of the load, e.g. by comparison with a nominal weight of the semi-trailer.

<FIG> illustrates a way in which the system may increase the safety of the vehicle combination by detecting a presence and characteristics of a trailer <NUM>. Depicted in the figure is a vehicle combination <NUM> with a towing vehicle <NUM> and a trailer <NUM>, viewed from above. The towing vehicle <NUM> and the trailer <NUM> enclose an articulation angle α. For a mirror replacement sensor <NUM> of the towing vehicle <NUM>, a field of view <NUM> is indicated. By tapping data from the mirror replacement sensor <NUM>, or from other exteroceptive sensors of the towing vehicle <NUM>, a presence of the trailer <NUM> may be detected by the safety system <NUM> located on the towing vehicle <NUM> (cf. Furthermore, several characteristics of the trailer <NUM> may be determined, including a trailer type (e.g. log-trailer, tanker, curtainsider trailer), the articulation angle α, or a height and/or width of the trailer <NUM>.

The extraction module <NUM> may be configured to estimate the type of the trailer <NUM> by means of training a neural network. The control module <NUM> may be configured to warn the driver, based on the estimated trailer type, if a current driving style of the vehicle combination <NUM> is not suitable for the trailer type identified, and/or the control module <NUM> may control an automated system of the towing vehicle <NUM> to drive accordingly.

The articulation angle α as well as the height and width of the trailer <NUM> may be estimated by identifying trailer properties from sensor data of sensors with the trailer <NUM> in their respective field of view. This is normally a static part of the scene. The extraction module <NUM> may be configured to segment an image, and to locate the trailer on it. After finding the trailer location on the image, the extraction module <NUM> may be configured to identify a current position or pose of the trailer <NUM> by comparing to a reference situation (as e.g. a straight position, which may be picked up at a time when the vehicle combination <NUM> is standing). For this task, the system <NUM> is advantageously configured to store and retrieve appropriate parts of the sensor data.

An estimation of geometric data of the trailer <NUM> may also be performed using scout sensor technology. Data from perception sensors installed on the towing vehicle with the trailer <NUM> in their respective fields of view may be employed in the extraction module <NUM> to estimate the geometric size of the trailer by utilizing known perspective properties of the sensors.

<FIG> illustrates a blind spot augmentation due to a trailer for an exemplary mirror replacement sensor <NUM>. Depicted is the same situation as in <FIG>. The field of view <NUM> of the mirror replacement sensor <NUM> is divided into a part <NUM> which is still visible, and a part <NUM> where the line of sight of the mirror replacement sensor <NUM> is obstructed by the trailer <NUM>. The extraction module <NUM> my be configured to detect the blind spot from the sensor data, e.g. through pattern recognition and localization of the trailer in the field of view <NUM>, through inference from trailer characteristics (cf. <FIG>), or through cross correlation with data originating from other sensors. The control module <NUM> may be configured to control driving tasks by taking into account the reduced field of view <NUM> of the mirror replacement sensor <NUM>. Such a control of a driving task may include a suppression of false alarms due to the reduced field of view <NUM>, a retention of a position of an object localized in the vicinity of the vehicle, even if the mirror replacement sensor <NUM> is no longer able to detect said object, or a check if a determined blind spot coincides with the expectation derived from the measures of the trailer <NUM> and the articulation angle α.

<FIG> illustrates a position determination of the trailer <NUM> by means of sensor data from two mirror replacement sensors <NUM>, <NUM>. Depicted is again the situation of <FIG>. In the figure, the fields of view <NUM>, <NUM> of the respective mirror replacement sensors <NUM>, <NUM> are indicated for the unobstructed case, i.e. as they would appear under absence of the trailer <NUM>. By combining measures of the trailer (cf. <FIG>) and blind spot information (cf. <FIG>), a precise position (or pose) of the trailer <NUM> is determined in the extraction module <NUM> (which is not depicted in the figure). The information on the precise pose is in particular useful for a tractrix determination.

<FIG> displays a schematic embodiment of parts of an architecture relevant for a tractrix determination. In this embodiment, at least a part of the system <NUM> is integrated into another system of the towing vehicle <NUM>: The figure shows the control module <NUM>, integrated into a module <NUM>, which here is an on-board controller. The on-board controller module <NUM> comprises software for highly automated driving (HAD), <NUM>, performing in particular an autonomous trajectory planning for the towing vehicle. The HAD software <NUM> is in particular configured to transmit the planned trajectory <NUM> to the control module <NUM>. With data flow directed by the on-board controller <NUM>, the control module <NUM> also receives fused sensor data <NUM> from sensors of the towing vehicle (via the data collection module <NUM> and the extraction module <NUM>; this is not depicted in the figure), and may furthermore be configured to receive data from the truck internal vehicle CAN <NUM>. Fused external sensor data may combine data from cameras, lidar and radar devices, and/or ultrasonic sensors. On the basis of the available data - in particular planned trajectory, geometric data of the towing vehicle <NUM>, trailer presence, the type of the trailer <NUM> (e.g. a semi-, central axle, draw bar, dolly, blink trailer), geometric data of the trailer <NUM> (such as width, height, length, and axle position), the articulation angle of the trailer <NUM> - an algorithm determines the outermost tractrix <NUM>, together with time data, of the vehicle trailer combination along one or more predefined trajectories (cf. The control module <NUM> is configured to share the tractrix <NUM> with the HAD software <NUM>.

Based on this output, the control module <NUM> my be configured to validate the planned trajectory. Stationary or moving objects, whose position may be extracted from exteroceptive sensor data, may be localized with respect to the curves of the tractrix <NUM>. If these objects are within the tractrix, a time of a collision may also be determined in the control module <NUM>, based on the time data.

<FIG> displays steps of a method for increasing a safety of a vehicle combination <NUM> with a towing vehicle <NUM> and a trailer <NUM>, wherein the towing vehicle <NUM> comprises a plurality of sensors <NUM> configured to provide sensor data about an environment or state of the vehicle combination <NUM>. The steps comprise:.

<FIG> shows some details of a tractrix determination as an embodiment of a part of the step of controlling S130 a driving task. The input for this part of the method comprises fused sensor data <NUM> and data from the truck internal vehicle CAN <NUM>.

The detailed steps comprise calculating S132 the initial position of the vehicle combination <NUM>, based on the available geometrical and sensor data. The term position, in this context, includes a relative position of various points of the trailer <NUM> as well as an orientation of the trailer <NUM>. An outcome of the step of calculating S132 the initial position may be improved by validating S133 the outcome by means of positions calculated in previous calculation cycles.

Another step comprises predicting S135, using the planned trajectories, the motion of the truck - trailer combination <NUM>, or specific points thereof. Predicting S135 may in particular include applying advanced vehicle models. In special cases, road conditions (e.g. a friction coefficient between the road and a tire) could be considered as well.

A further step includes calculating S137 a tractrix from moving the vehicle combination <NUM> along the trajectory of the outermost assumed positions, which when connected result in one or more tractrices <NUM> along the planned trajectory. As an important advantage, the algorithm may not only record the outermost positions, but also a time frame, detailing the point in time when the vehicle combination <NUM> will assume a particular position. A further advantage of the proposed method consists in the lack of a requirement of any sensors on the trailer <NUM>, while still being able to predict motion and tractrix of the vehicle combination <NUM>.

The methods detailed in <FIG> may also be computer-implemented. A person of skill in the art would readily recognize that various steps of the above-described methods may be performed by programmed computers. Embodiments are also intended to cover program storage devices, e.g., digital data storage media, which are machine or computer readable and encode machine-executable or computer-executable programs of instructions, wherein the instructions perform some or all of the acts of the above-described methods, when executed on the computer or processor.

The description and drawings illustrate the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the subject matter as defined by the claims and supported by the description, and are included within its scope.

Furthermore, while each embodiment may stand on its own as a separate example, it is to be noted that in other embodiments the defined features can be combined differently, i.e. a particular feature described in one embodiment may also be realized in other embodiments. Such combinations are covered by the disclosure herein, unless it is stated that a specific combination is not intended.

Claim 1:
A safety system (<NUM>) for a vehicle combination (<NUM>) with a towing vehicle (<NUM>) and a trailer (<NUM>), the towing vehicle (<NUM>) comprising a plurality of sensors (<NUM>) configured to provide sensor data about an environment of the vehicle combination (<NUM>) or a state of the towing vehicle (<NUM>) wherein the plurality of sensors (<NUM>) includes exteroceptive sensors,
the safety system comprising:
a data collection module (<NUM>) for collecting the sensor data;
an extraction module (<NUM>) for extracting, from the sensor data, information about a presence of the trailer (<NUM>) or about a state of the trailer (<NUM>);
a control module (<NUM>), configured to control, based on the extracted information, at least one driving task, or to provide the information to another component of the towing vehicle (<NUM>) in order to increase the safety of the vehicle combination (<NUM>),
characterized in that
the control module (<NUM>) is configured to determine blind spots of the exteroceptive sensors caused or increased by the trailer, and to control at least one automated or
assisted driving task based on the determined blind spot.