EP4313704A1

EP4313704A1 - Method for actuating a vehicle brake system of a vehicle, and towing vehicle

Info

Publication number: EP4313704A1
Application number: EP22709702.9A
Authority: EP
Inventors: Julian van Thiel
Original assignee: ZF CV Systems Global GmbH
Current assignee: ZF CV Systems Global GmbH
Priority date: 2021-03-24
Filing date: 2022-03-01
Publication date: 2024-02-07
Also published as: CN117083208A; WO2022199992A1; DE102021107303A1; US20230415713A1

Abstract

The invention relates to a method for actuating a vehicle brake system (34) of a vehicle (3), comprising a towing vehicle (1) and a trailer (2.n) which can be coupled thereto. The towing vehicle (1) has a trailer interface (7), by means of which interface signals (S7) can be transmitted between the towing vehicle (1) and the coupled trailer (2.n). The method has at least the following steps: - reading a sensor signal from a vehicle sensor (6), - ascertaining and providing a monitoring result by analyzing the sensor signal, wherein the monitoring result indicates whether at least one trailer (2.n) is coupled or not, and the sensor signal and/or the monitoring result is/are ascertained independently of the interface signals (S7) which act on the trailer interface (7) and/or are transmitted via the trailer interface (7) when the trailer (2.n) is coupled; - selecting a braking strategy on the basis of the monitoring result and/or the sensor signal; and - actuating the vehicle brake system (34) of the vehicle (3) on the basis of the selected braking strategy in the event of a brake request.

Description

Method for controlling a vehicle braking system of a vehicle and towing vehicle

The present invention relates to a method for controlling a vehicle brake system of a vehicle, the vehicle having at least one towing vehicle and at least one trailer being able to be coupled to the towing vehicle. The present invention also relates to a towing vehicle with a towing vehicle braking system for carrying out the method.

Safe and efficient braking of the vehicle must be ensured for the safety of road users, the vehicle itself and to comply with legal requirements. Particularly in the case of vehicles with an electro-pneumatic braking system without a trailer stability control system, safe and efficient braking requires knowledge of whether the vehicle consists only of a towing vehicle or whether the vehicle consists of a towing vehicle and at least one trailer coupled to the towing vehicle consists. For example, in the case of a vehicle consisting of a towing vehicle and a trailer without its own trailer stability control system, when the car and trailer brakes, care must be taken to ensure that the trailer does not break away. This is usually achieved by braking less hard than in a vehicle that consists only of a towing vehicle, which in turn results in a longer braking distance.

If heavy braking is required, for example emergency braking, a braking strategy is sought in which the shortest possible braking distance can be achieved while the vehicle is still controllable. In the event that the vehicle is controlled and braked by a human driver, the driver can, for example, by looking into the side mirror of the towing vehicle, the driving behavior or the driving dynamics of a trailer attached and adapt its braking strategy accordingly.

Furthermore, modern vehicles usually have electronic braking systems (EBS), driver assistance systems or stability control systems (ABS, ESC, ASR, RSC, etc.) and emergency braking systems, which are set up for automated or partially automated braking of the vehicle in order to make it autonomous to brake, taking instabilities into account, or to support the driver. In this case, both the towing vehicle and the trailer can have corresponding automatically or partially automatically controllable braking and/or driving assistance systems. In the event that the vehicle has such automated or semi-automated systems that also intervene when braking, the full braking potential can be exploited when braking the towing vehicle or trailer, since possible instabilities can be corrected accordingly.

In order to brake the vehicle efficiently, it must first be determined with sufficient certainty whether the vehicle consists only of a towing vehicle or whether the vehicle consists of a towing vehicle and at least one trailer. If a trailer is not actively detected, it is always assumed for safety reasons that the vehicle consists of a towing vehicle and at least one trailer, since non-detection could occur due to a defective connection to the trailer. For example, it may be the case that the (radio) connection/plug connection required for communication between the towing vehicle and the trailer, e.g. PLC (Power Line Communication) or trailer CAN (ISO 11992), is not activated/plugged in , or there could be another defect in a communication component in the towing vehicle or trailer. Since it can be assumed in this case that there is no trailer stability control due to a possibly defective connection, the vehicle must be braked with an appropriately selected and coordinated braking strategy, with the braking strategy not using the full braking potential due to the missing or faulty stability control becomes. However, if the vehicle actually only consists of a towing vehicle, this leads to the disadvantage of an unnecessarily long braking distance. At the same time, braking power is saved for braking a trailer that is not actually present.

Against this background, the invention is based on the object of enabling safe and efficient braking of a vehicle, in particular for a vehicle which consists only of a towing vehicle.

This object is achieved by a method and a towing vehicle according to one of the independent claims. The dependent claims indicate preferred developments.

According to the invention, a method is therefore provided for controlling a vehicle braking system of a vehicle, the vehicle having at least one towing vehicle and at least one trailer being able to be coupled to the towing vehicle, the towing vehicle having a trailer interface, with electrical and/or pneumatic and/or hydraulic interface signals can be transmitted via the trailer interface between the towing vehicle and at least one coupled trailer, with at least the following steps:

- Reading in at least one sensor signal from at least one vehicle sensor, the vehicle sensor being designed to generate the sensor signal depending on whether at least one trailer is coupled or not. The vehicle sensor can therefore initially be any sensor be in the vehicle that interacts directly or indirectly with the at least one trailer.

- Determining and providing a control result by evaluating the sensor signal, the control result indicating whether at least one trailer is coupled to the towing vehicle or not, the sensor signal and/or the control result being independent of the Intersection parts signals are generated or determined, which act on the trailer interface and/or are transmitted via the trailer interface when at least one trailer is coupled to it. In this way, it is advantageously possible to check whether a trailer is present without resorting to quantities or signals which are transmitted during normal operation between the towing vehicle and the respective trailer in question in order to ensure or implement the braking operation. It is thus advantageously possible to fall back on other sources if, for example, the trailer interface to the trailer in question is defective or plug connections are not being used correctly, knowingly or unknowingly. Nevertheless, in this case too, for safe braking operation, it must be taken into account that the trailer in question is present, even if it can only be controlled to a limited extent, for example trailer stability control is no longer available because the energy supply to the trailer in question is interrupted is.

- Selection of a braking strategy depending on the control result and/or the sensor signal, the braking strategy indicating how the vehicle's braking system of the vehicle is controlled, and

- Control of the vehicle braking system of the vehicle depending on the selected braking strategy in the presence of a fully automated or partially automated or manual braking request. According to the invention, a towing vehicle is also provided, to which at least one trailer can be coupled and with which the process according to the invention can be carried out, the vehicle thus formed being able to consist of a large number of configurations or constructions. For example, the vehicle can be a semi-trailer with a fifth wheel coupling, a road train with a drawbar coupling, or a road train with a large number of trailers. Various embodiments of the method are described below, with the individual embodiments each applying independently of one another to the method and the towing vehicle. In addition, the embodiments can be combined with one another.

The trailer interface of the towing vehicle is an interface via which, when a trailer is coupled to the towing vehicle, communication with the relevant trailer is possible by means of an interface signal (electrical, hydraulic, pneumatic) or a control signal (electrical, hydraulic, pneumatic) can be transmitted. Communication can also be unilateral or based solely on a reaction from the trailer in question. The trailer interface can also be used to supply energy to the at least one trailer, in particular to enable trailer stability control.

Electrical interface signals are transmitted via the trailer interface, for example by means of a power line communication (PLC) or a trailer CAN (ISO 11992), with the towing vehicle and the relevant trailer then normally actively exchanging information via an electrical plug connection be able. An electrical interface signal is also transmitted via the trailer interface by measuring the cold resistance of electrical components of the trailer (rear lights, indicators, etc.) by the towing vehicle or from the towing vehicle. Another example of a pneumatic and/or hydraulic interface signal, which is normally transmitted via the trailer interface if a trailer is coupled, is a pneumatic or hydraulic control signal (trailer control signal) from the towing vehicle braking system to the Trailer braking system to actively brake the trailer in question depending on the braking request. If no trailer is coupled, the control signal is only fed to the trailer interface as an interface signal, i.e. it is present at its pneumatic control input.

A further example of an interface signal is an electrical and/or pneumatic or hydraulic test pulse supplied to the trailer interface by the towing vehicle for testing the trailer interface. The reaction to such a test pulse differs with and without a trailer, since the interface signal acting on the trailer interface is transmitted or not, and the reaction can be evaluated by a pressure sensor or a corresponding sensor system in the towing vehicle or in the trailer .

Based on the intersection signals mentioned, it is at least possible to draw a direct or indirect conclusion as to whether a trailer is coupled to the towing vehicle or whether no trailer is coupled to the towing vehicle, since these intersection signals acting at the trailer interface vary be transmitted via the trailer interface after the presence of a trailer or not.

The sensor signal according to the invention, which is used to determine the control result, differs significantly from this intersection part signal, since it does not contain such a signal or does not take it into account or is not dependent on such a Fenden trailer transmitted or transferable interface parts signal is. Therefore, a strict distinction must be made between these two signals. An evaluation of a variable dependent on the intersection signal is therefore not mandatory, at least for the course of the method according to the invention. In this way, a coupled trailer can also be detected without a feed or transmission of interface signals to or via the trailer interface to the trailer in question, based only on the sensor signals. The interface signals can only be used in additional, supplementary detection steps if the trailer detection according to the invention is to be expanded and/or made plausible, for example.

It is preferably provided that the at least one sensor signal is provided directly or indirectly by a vehicle sensor, which is selected from the group consisting of:

Radar sensor and/or camera and/or lidar sensor and/or ultrasonic sensor and/or axle load sensor and/or coupling sensor of an automated trailer device and/or articulation angle sensor system. Other sensors that can monitor the area close to the vehicle in order to deduce the presence of a trailer can also be used. The sensor signal can be provided directly from the vehicle sensor to a control unit that performs the evaluation, or indirectly via an intermediate entity such as a central control computer or central units of other systems in the vehicle, with the sensor signals then being transmitted for example via the data bus of the vehicle.

As a rule, modern vehicles already have such vehicle sensors, so that these can be used twice in the present case in order to be able to draw conclusions about a coupled trailer.

A trailer coupled to a towing vehicle is usually located in the rear area of the towing vehicle and thus in the vicinity of the towing vehicle, which is detected by the respective sensors. If a vehicle consists of several trailers (roadtrain), the respective trailers as part of the vehicle can also have corresponding vehicle sensors, which in turn can then detect subsequent trailers without having to resort to interface signals for these trailers in question. From this, one or more trailers can be directly inferred if, for example, a distance between the individual vehicle parts is monitored over a period of time via the sensors detecting the surroundings, in particular when the towing vehicle is accelerating and/or braking.

A radar sensor, ultrasonic sensor, lidar sensor or camera can be used to continuously determine the distance to objects in the vicinity of the vehicle, which usually requires a visual representation for the human driver, automatic braking systems and/or steering systems of autonomous vehicles is already being used in the vehicle. In addition, a trailer located in the vicinity of the vehicle can then also be detected using the sensor signals.

In principle, however, the vehicle sensor can also be a sensor in the area that detects the area around your own vehicle, for example in parking lots, loading ramps or toll bridges. This enables the use of sensors that are not located in or on the vehicle, but which nevertheless map the vehicle environment. It is conceivable that corresponding cameras have a better viewing angle or that additional information such as a trailer type and/or the number of trailers coupled can be determined more easily and that this information can then be made available to the evaluating control unit in the vehicle. An axle load sensor also provides a signal that is independent of the signals from the cutting parts. If the towing vehicle is, for example, the towing vehicle of a semi-trailer, hitching up a trailer or semi-trailer significantly changes the axle loads of the towing vehicle. This in turn allows conclusions to be drawn from the measured axle loads of the towing vehicle as to whether a trailer is coupled to the towing vehicle or not.

A coupling sensor of an automated hitch also provides a signal that is independent of the above-mentioned interface signals. A sensor, for example a contact sensor or an inductive proximity switch or a light barrier, is fitted in the coupling mouth of an automated trailer device in the area of a coupling bolt for this purpose. The coupling sensor thus immediately detects the presence of a coupling in the coupling mouth, which in turn allows conclusions to be drawn as to whether a trailer is coupled to the towing vehicle or not.

Depending on the type of vehicle sensor, the respective processing units, in particular the control unit, are set up, for example, to carry out image recognition, force evaluation or time course determination of the sensor signal.

A large number of possibilities are conceivable as braking strategies, which are selected depending on whether a trailer is detected or not. A braking strategy generally represents a strategy with which braking forces and time profiles the individual brakes of the vehicle are braked in order to implement a braking request that is present. A braking request can be, for example, a manual request by a human driver using an operating element, for example a brake pedal, or an automatic Automated specification of a brake request signal, for example given by an assistance system or a stability control system (ABS, ESC, ASR, AEBS, etc.) or a request from a control computer of an autonomous vehicle.

The braking request can preferably also be selected or modified depending on the braking strategy or the sensor signal or the control result if, for example, a trailer without an existing or functional trailer ABS control system was detected and instabilities from the towing vehicle were therefore detected be avoided by specifying a stabilizing braking request as part of a “redundant” stability control.

It can preferably be provided that as a braking strategy

- a tow vehicle braking strategy is selected if the control result indicates that no trailer is coupled, or

- a first combination braking strategy or a second combination strategy is selected if the control result indicates that at least one trailer is coupled.

This generally covers the two problematic cases with regard to the driving behavior or driving dynamics of the vehicle, ie that the entire vehicle consists of only one towing vehicle or that the vehicle consists of a towing vehicle and at least one trailer coupled to the towing vehicle. It can thus advantageously be achieved that, in the event of a braking request, a braking strategy adapted to the vehicle is selected, so that safe and efficient braking of the vehicle is possible. In particular, in the event that the vehicle consists of only one towing vehicle, which can be reliably detected from the sensor signals, rapid braking or a short Braking distances are made possible, since the trailer driving behavior or the driving dynamics of the trailer or the presence of a trailer is generally not to be taken into account.

It is therefore preferably provided that

- If the first combination braking strategy is selected, preferably in the towing vehicle braking system, a towing vehicle control signal for braking the towing vehicle and/or a trailer control signal for braking the at least one trailer is generated as a function of a braking request that is present, assuming that at least one trailer is present is coupled, which follows from the sensor signals, and at least one coupled trailer has no or no functional trailer stability control, which e.g. follows from the fact that the trailer could not be recognized otherwise,

- If the second combination braking strategy is selected, a towing vehicle control signal for braking the towing vehicle and/or a trailer control signal for braking the at least one trailer is generated as a function of a braking request that is present, assuming that at least one trailer is coupled and the at least one coupled trailer has a functional trailer stability control system, or

- If the towing vehicle braking strategy is selected, a towing vehicle control signal is generated for braking the towing vehicle as a function of a braking request present, assuming that no trailer is coupled, which follows from the sensor signals and the towing vehicle is only to be braked , With the towing vehicle control signal a towing vehicle braking system in the towing vehicle and with the trailer control signal a trailer braking system in the respective coupled trailer being controlled and the towing vehicle braking system and the trailer braking system forming the vehicle braking system. As a result, for example, for the towing vehicle without a trailer coupled or with a trailer coupled and the trailer stability control function, in particular trailer ABS control and/or trailer RSC control, the brakes can be controlled with higher brake pressures (towing vehicle braking strategy) than for the towing vehicle with a hitched trailer and without a functioning trailer stability control. This enables a significantly shorter braking distance for the towing vehicle without a trailer coupled and better controllability for a towing vehicle with a trailer coupled. According to an extended first combination braking strategy, it can also be assumed that the trailer cannot be controlled at all, ie not via the trailer control signal either, ie it remains unbraked. Accordingly, the braking of the car-trailer combination only has to be carried out via the towing vehicle. Different braking strategies with regard to the braking duration are also possible. Furthermore, different braking strategies are possible with regard to (brake) energy recovery when braking, such as preferred electrical braking with an electrically driven towing vehicle, for example.

It is preferably also provided that the towing vehicle control signal for braking the towing vehicle and/or the trailer control signal for braking the at least one trailer when the first combination braking strategy is selected depending on a number of detected trailers and/or depending on a trailer type of one detected trailer is generated. Therefore, within the first combination braking strategy, an additional distinction can be made or, as it were, a sub-braking strategy can be used for even more targeted braking of the towing vehicle. The number of trailers recognized and/or the trailer type can preferably be determined as a function of the Sensor signal determined by at least one of the vehicle sensors who the.

This additional information about the trailer type and/or a number of trailers coupled and possibly other attributes that follow from the trailer type, such as a number of axles of the respective trailer, a trailer construction (semi-trailer, drawbar trailer, etc.) of the respective trailer, a trailer brake system type of the respective trailer, a trailer loading condition and/or a trailer center of gravity of the respective trailer, within the first combination braking strategy, a targeted activation of the brakes of the towing vehicle can be carried out via the towing vehicle control signal or the brakes of the Trailers take place via the trailer control signal, in which this information is taken into account. For example, for a road train, consisting of a towing vehicle and several long trailers, which were detected via the sensor signals, a different deceleration within the combination braking strategy is preferred with regard to stability than for a towing vehicle with only one small coupled trailer that was detected via the sensor signals.

The specific physical driving properties of the respective trailer type or trailer construction, e.g. of semi-trailers and drawbar trailers, can also be used after reliable detection, e.g. via vehicle sensors, to generate the towing vehicle control signal or the trailer control signal and thus virtually a to implement the optimal sub-braking strategy of the first combination braking strategy in the respective driving situation and thereby to keep the combination stable despite the lack of trailer stability control. Furthermore, for example, the information about the number of axles of the trailer in question can be a valuable indication that is further processed in the towing vehicle braking system is used to generate the towing vehicle control signal or the trailer control signal and thus enable optimized braking.

The information about the number of trailers coupled can be used in particular to check whether the number of trailers with error-free or functioning trailer stability control (e.g. detected via the interface signals) corresponds to the number via the vehicle sensors hitched trailers detected. In this way, it can be ensured using the vehicle sensors that all trailers have a functioning trailer stability control system or not and that the respective braking strategy can be selected depending on this.

It is preferably provided that the towing vehicle control signal for braking the towing vehicle and/or the trailer control signal for braking the at least one trailer when the towing vehicle braking strategy or the first combination braking strategy or the second combination braking strategy is selected in the towing vehicle -Brake system of the towing vehicle is generated in order to implement a braking request, the trailer control signal being transmitted via the trailer interface to the trailer braking system in the trailer

This takes account of the fact that the method is mainly used when trailer detection via the intersection signals cannot provide reliable information and/or the trailer braking system is not fully functional, for example because the electrical control is not error-free is working. Reliable control of the trailer braking system can therefore be carried out when there is a braking request solely via the traction vehicle braking system, which can be reliably controlled in this case, preferably via the pneumatically specified trailer control signal, in order to achieve controllable and monitorable braking of the entire vehicle . The method can also be used to create redundancy for trailer detection, which combines an evaluation of the intersection signal on the one hand with an evaluation of the sensor signal on the other.

If, for example, the (radio) connection/plug connection required for communication via the trailer interface is not activated/plugged in or is defective, so that no trailer can be determined on the towing vehicle via the trailer interface, the evaluation of the Sensor signal carried out an additional determination or plausibility. The conventional method is thus extended by the inventions to the invention, independent of the intersection signal method of trailer identification. In this way, the problem described at the outset, which cannot be determined with sufficient certainty as to whether the driving behavior or the driving dynamics of a trailer must be taken into account when braking or not, can be countered.

In a further embodiment, the control result of the control unit, which is independent of the intersection part signal, is compared with a detection result from an additional trailer detection unit, the detection result preferably being dependent on the intersection part signals that act on the trailer interface and/or transmitted via the trailer interface if a trailer is coupled,

- A first comparison result being provided as the comparison result if both the control result and the recognition result indicate that a trailer is coupled, or

- a fifth comparison result being provided as the comparison result if the control result indicates that a trailer is coupled and the detection result indicates a coupled trailer with a defect,

- a fourth comparison result being provided as the comparison result if both the control result and the detection result indicate that no trailer is coupled,

- wherein a third comparison result is provided as a comparison result if the control result indicates a coupled trailer and the detection result of the trailer detection device indicates no coupled trailer, and

- A second comparison result being provided as the comparison result if the control result does not indicate a coupled trailer and the detection result of the trailer detection device indicates a coupled trailer with or without the presence of a defect, the braking strategy then also being selected depending on the comparison result .

By comparing the control result determined by means of the sensor signal with a recognition result determined elsewhere, which is preferably based on an alternative database, since the control result is determined in a control unit independently of the recognition result of the trailer recognition device therefore an additional check or plausibility check of the results is carried out. Additional security is thus achieved with regard to whether the respective result is actually correct or not. The comparison makes it possible to say with greater certainty whether a trailer is coupled to the towing vehicle or not, and the braking strategy can therefore be selected more reliably.

Any discrepancies in the results can also provide information about the vehicle condition: In the third comparison result, a trailer coupled to the towing vehicle was detected using the sensor signal, while no trailer coupled was detected using the trailer detection unit based on the interface signals. From this it could be concluded, for example, that the trailer recognition unit is defective or there is an error of any kind. In the case of a trailer identification unit based on an electrical and/or pneumatic and/or hydraulic connection between trailer and towing vehicle, only the connection could be defective, for example the connector plug not be plugged in or not plugged in correctly.

In the second result of the comparison, no trailer coupled to the towing vehicle was detected by means of the sensor signal, while a trailer coupled to it was detected by means of the trailer detection unit. The trailer detection unit could therefore be defective, or the evaluation of the sensor signals in the control unit could be inaccurate, or a combination of both.

The driver or a person monitoring the vehicle, for example, can be informed about this vehicle status or the result of the comparison via a user interface, for example a display. This makes it possible, for example, for the human driver or a person monitoring the vehicle to draw conclusions about the state of the vehicle. For example, it can be assumed that in the case of the first or the fourth comparison results, the corresponding vehicle sensors and devices are functioning correctly and the connections between the towing vehicle and the coupled trailer are also correctly connected. In the case of the second or the third comparison result, it can be assumed, for example, that one of the errors or defects mentioned above is present, whereupon this can be checked. Therefore, additional information about the condition of the vehicle can be made available.

In a further embodiment it is provided that

- In the case of the first comparison result, the second combination braking strategy is selected in order to implement the braking request,

- in the fourth comparison result, the towing vehicle braking strategy is selected in order to implement the braking request, and - in the case of the second, the third or the fifth comparison result, the first combination braking strategy is selected in order to implement the braking request.

Appropriate selection of braking strategies offers safe and efficient braking of the vehicle and thus a high level of safety for the vehicle itself and road users. In the first comparison result, it was determined on the basis of at least two mutually independent data bases that a trailer, in particular with a functioning trailer stability control system, is coupled to the towing vehicle. Accordingly, the second combination braking strategy is selected with activation of the towing vehicle braking system and/or the trailer braking system and implemented when braking is requested in order to utilize the full braking potential for this driving condition. If, in the fifth comparison result, at least the presence of a trailer is detected with a defective electronic control of the trailer, in particular a faulty trailer stability control system, at least the first combination braking strategy is applied in order to brake the combination in a correspondingly reliable and stable manner when the trailer is present.

On the other hand, in the case of the fourth comparison result, due to the at least two independent data bases, it can be assumed with great certainty that no trailer is actually coupled to the towing vehicle, so that the towing vehicle braking strategy is selected, which, for example, compared to the first combination - Braking strategy results in a shorter braking distance for the towing vehicle.

In the case of the second or third comparison result, as explained above, it is not absolutely clear why the comparison result is different. For safety reasons, it is assumed that a trailer is attached to the towing vehicle is coupled and the first combination braking strategy is selected accordingly.

The invention is explained in more detail below with reference to the accompanying drawings of some embodiments. Show it:

1 shows a schematic plan view of a vehicle set up for carrying out the method according to the invention;

2 shows a flow chart of an exemplary embodiment of the method;

3 shows a further flow chart of an embodiment of the method; and

4 shows an example of a comparison routine of results.

FIG. 1 shows a schematic plan view of a vehicle 3 or vehicle combination, which is set up for carrying out the method according to the invention. The vehicle 3 consists of a towing vehicle 1 and trailers 2.n (with n=1, 2, . . . N) of a specific trailer type T.i (with i=1, 2, Trailer 2.1 of a first trailer type T.1 and a coupled second trailer 2.2 of a second trailer type T.2, the second trailer 2.2 being merely indicated and not described further.

The trailer type Ti characterizes the type of the respective trailer 2.n, wherein in the trailer type Ti, for example, information about the respective trailer 2.n with regard to a number of axles AN, a trailer construction AK (e.g. semi-trailer AK1, drawbar trailer AK2, .. .), A trailer braking system type AB (e.g. with a trailer ABS control 39a), a trailer loading condition AZ (full, half full, empty) and/or a position of a trailer center of gravity AS (high, low) can be included. With the help of these attributes and possibly further information on the respective trailer 2.n, the braking of the entire vehicle combination can be optimized in the following when recognizing a specific trailer type Ti, in particular with regard to driving stability, as explained in more detail below.

The vehicle 3 consisting of the towing vehicle 1 and one or more trailers 2.n of a specific trailer type T.i has a vehicle braking system 34 which is divided into a towing vehicle braking system 32 arranged in the towing vehicle 1 and a towing vehicle braking system 32 in the corresponding trailer 2.n ordered trailer braking system 33, which are matched to each other or can be controlled individually in order to brake the entire vehicle 3 according to a manual braking request 19 via a control element B or automatically via a braking request signal SB.

The towing vehicle braking system 32 has a towing vehicle control device 35 with a towing vehicle stability control 35a and corresponding towing vehicle control lines 20a for controlling individual towing vehicle brakes 37 via a towing vehicle control signal S1, with the towing vehicle control signal S1 depending on Execution of the towing vehicle braking system 32 can be generated individually for each axle or wheel. The towing vehicle stability control 35a ensures that the towing vehicle 1 in particular remains stable when the towing vehicle brakes 37 are actuated for individual axles or wheels, with the towing vehicle stability control 35a containing the usual stability functions for this purpose (RSC, ABS, ASR, ESC, .. .).

The towing vehicle control lines 20a, which are shown only schematically in FIG. 1, can have pressure lines and/or electrical lines. point, so that the towing vehicle control signal S1 can be a hydraulic or a pneumatic or an electrical control signal, which can also be converted between the individual "media" via corresponding control valves. This allows purely hydraulic or purely pneumatic or purely electrical activation of the towing vehicle brakes 37 or a combination thereof (electro-pneumatic, electro-hydraulic, hydraulic-pneumatic), with additional control valves, not shown, being required for combined activation are to be provided in the towing vehicle control lines 20a.

The trailer braking system 33 in the first trailer 2.1 has a trailer control device 39 with a trailer stability control 39a, in particular a trailer ABS control 39b and/or a trailer RSC control 39c, and corresponding trailer control lines 20b for an activation of individual trailer brakes 41 in the first trailer 2.1 via a trailer control signal S2, the trailer control signal S2 depending on the design of the trailer brake system 33 being generated or specified individually for each axle or wheel. The trailer ABS control 39a additionally ensures that the wheels of the relevant trailer 2.n do not lock when triggered by the trailer control signal S2, in order to keep the relevant trailer 2.n stable. In addition, the trailer RSC control 39c can prevent the respective trailer 2.n from tipping over by appropriate braking interventions on the trailer 2.n.

As in the towing vehicle 1, a purely hydraulic or a purely pneumatic or a purely electrical control of the trailer brakes 41 can be made possible, or a combination thereof (electro-pneumatic, electro-hydraulic, hydraulic-pneumatic). The structure of the second trailer 2.2 or further trailers 2.n can also be designed accordingly. The trailer interface 7 is arranged in the rear of the towing vehicle 1 and is used for the transmission of interface signals S7, ie any signals that are transmitted between the towing vehicle 1 and the first trailer 2.1 and possibly other trailers 2.n are to be “supplied” to the trailer interface 7. This can be done in a standardized way. According to one embodiment, the signals transmitted as interface signals S7 can form the data basis for a trailer detection unit 24, as will be explained in more detail later.

The trailer interface 7 is designed to use a pneumatic and/or hydraulic and/or electrical signal generated in the towing vehicle 1 or in the respective trailer 2.n and fed to the trailer interface 7 as an interface signal S7 between the towing vehicle 1 and to transfer the trailer concerned 2.n. For example, a pneumatic trailer control signal S2 generated by the towing vehicle brake system 32, which is formed during normal operation, for example as a function of the towing vehicle control signal S1 intended for the front axle of the towing vehicle 1, can be transmitted as a pneumatic interface signal S7 via the trailer interface 7 be transferred to the relevant trailer 2.n in order to ensure a corresponding deceleration of the relevant trailer 2.n. The deceleration of the trailer 2.n is thus specified in this case by the towing vehicle 1, for example by the towing vehicle braking system 32. If a trailer stability control 39a is present, the trailer control signal S2 is generated during normal operation under the condition that the trailer stability control 39a can correct any instabilities (ABS, RSC) that may occur. Accordingly, higher control pressures can be used.

In principle, with such a purely pneumatic control of the trailer brakes 41 of a trailer 2.n, the trailer control device 39 with a trailer stability control 39a can also be omitted if the above Given (pneumatic) trailer control signal S2 for controlling the trailer brakes 41 via the trailer interface 7 (via an interface steep signal S7) is transmitted to the trailer brake system 33. However, without such a trailer control device 39, the trailer stability control system 39a implemented therein cannot correct any instabilities that may occur. This must be taken into account when generating the pneumatic trailer control signal S2, in which case lower control pressures may then be transmitted to the trailer 2.n in order to prevent the wheels from locking or the trailer 2.n from tipping over.

Any electrical signals can also be transmitted via the trailer interface 7 as interface signals S7 from the towing vehicle 1 to the trailer concerned 2.n or vice versa from the respective trailer 2.n to the towing vehicle 1 in order to ensure a coordinated and safe enable ferry operations. Such a trailer interface 7 can also be provided between the first trailer 2.1 and the second trailer 2.2 or between each additional trailer 2.n. In particular, the trailer control device 39 can also be supplied with energy via the trailer interface 7, in particular to enable trailer stability control 39a.

The towing vehicle 2 also has one or more vehicle sensors 6, the generated and output sensor signals S6 of which enable a conclusion to be drawn as to whether one or more trailers 2.n is or are coupled to the towing vehicle 1 or not. The sensor signals S6 can be transmitted, for example, via the vehicle's internal bus system (eg CAN bus). Radar sensors 6a and/or cameras 6b and/or lidar sensors 6c and/or ultrasonic sensors 6d, which are based on an optical measuring principle, can be used as vehicle sensors 6, for example. By means of these optically acting vehicle sensors 6; 6a, 6b, 6c, 6d, an environment U around the vehicle 3 can be monitored or observed, with detection ranges of the vehicle sensors 6; 6a, 6b, 6c, 6d are to be aligned accordingly in order to enable conclusions to be drawn about a coupled trailer 2.n.

In the arrangement shown in FIG. 1, for example, the coupled first trailer 2.1 can be recognized from a temporal monitoring of the sensor signal S6, which is generated and output by the radar sensor 6a as the vehicle sensor 6. It can be taken into account in particular who the that the sensor signal S6 of the radar sensor 6a indicates both when braking and when accelerating the towing vehicle 1 that a constant distance D between the first trailer 2.1 and the towing vehicle 1 is present. A control unit 30 evaluating the sensor signal S6 in the towing vehicle 1, which can be designed as software or as a flardware unit, for example, can therefore output as a control result 12 based on the sensor signals S6 from the radar sensor 6a, that an indicated coupled trailer 2 is present. This applies correspondingly when using the other optically acting vehicle sensors 6 mentioned; 6a, 6b, 6c, 6d.

Furthermore, as vehicle sensors 6, an axle load sensor 6e and/or a coupling sensor 6f of an automated trailer device 43 and/or an articulation angle sensor 6g can be used as mechanically acting sensors in order to draw conclusions about a coupled trailer 2.n. For this purpose, the axle load sensor 6e measures the forces acting on the axles of the towing vehicle 1, which change under mechanical action when the first trailer 2.1 is coupled. The coupling sensor 6f can be a contact sensor in the coupling mouth of an automated trailer device 43, which, when a trailer 2.n is coupled, gives a corresponding sensor signal S6 under mechanical action. The articulation angle sensor 6g gives a corresponding articulation angle between see the towing vehicle 1 and the trailer 2.n or between two trailers 2.n, which depends on whether a trailer 2.n is present or not. Therefore, based on the sensor signals S6 of these mechanically acting vehicle sensors 6; 6e, 6f, 6g are output by the control unit 30 as a control result 12, whether a trailer 2.n is coupled to the towing vehicle 1 or not.

All of these vehicle sensors 6 (optical and/or mechanical) can be provided in combination with one another or individually. Alternatively or in addition, vehicle sensors 6, which are arranged on one of the trailers 2.n, can be used to determine whether another trailer or a following trailer 2.n is present. In this case, the vehicle sensors 6 preferably do not have to be additionally installed. Vehicle sensors 6, which are already present in vehicle 1 anyway, are used much more. This allows easy retrofitting given ben.

Other vehicle sensors 6, which demonstrably generate and output different sensor signals S6 when a trailer 2.n is coupled than without a trailer 2.n coupled, can also be considered for such an evaluation in the control unit 30. The invention is only limited to the fact that the control unit 30 generates the control result 12, which is based on the measurements of the respective vehicle sensors 6, independently of a signal that is fed to the trailer interface 7 for the trailer in question 2.n and at an actually coupled trailer 2.n is also transmitted as an interface signal S7 via the trailer interface 7 to the relevant trailer 2.n.

The trailer 2.n in question is the trailer 2.n whose presence is to be checked by the method according to the invention. Therefore, the control result 12 can be based, for example, on sensor signals S6 are based, which are generated and output by a vehicle sensor 6 on the first trailer 2.1 and are transmitted via the trailer interface 7 from the first trailer 2.1 to the towing vehicle 1 if the first trailer 2.1 is not the trailer in question 2.n, whose Presence is to be checked depending on the transmitted sensor signals S6. Nevertheless, based on these sensor signals transmitted via the trailer interface 7 from the first trailer 2.1 to the towing vehicle 1

56 according to the method according to the invention, a control result 12 is determined, which indicates whether a second trailer 2.2 is present. In this case, the control result 12 is namely generated independently of a signal that is fed to the trailer interface 7 to the relevant second trailer 2.2 and, if necessary, is or could also be transmitted via this.

For example, there is a pressure sensor that measures the pressure of the pneumatic trailer control signal S2 generated in the towing vehicle 1, which is transmitted to the trailer interface 7 to the relevant first trailer 2.1 and, when the first trailer 2.1 is coupled, via the interface signal S7 is also transmitted to the first trailer 2.1, no vehicle sensor 6, which the control unit 30 of the invention uses to determine the control result 12. Even if a measurement of this pressure can be used to determine whether a trailer is coupled or not, the control unit 30 does not use such a pressure sensor signal as a sensor signal to determine whether a trailer 2.n is coupled or not S6 back, since such a pneumatic monitoring is dependent on the interface signal S7 transmitted to or via the trailer interface 7 to the relevant first trailer 2.1. Based on this, at most a plausibility check can take place. This applies in an analogous manner to hydraulic or electrical signals, which act as interface signals

57 can be transmitted to or via the trailer interface 7 to the relevant trailer 2.n. The sensor signals S6 of the respective vehicle sensors 6 are received by a receiving unit 29 and transmitted to the control unit 30 for evaluation, with the receiving unit 29 being part of the control unit 30. After the respective sensor signal S6 has been evaluated, the control result 12 is made available to an output unit 31 . The control result 12 can preferably contain direct information about whether one (or more) trailers 2.n is (are) coupled to the towing vehicle 1 or not (“Yes”/”No”).

FIG. 2 shows a flow chart of an exemplary embodiment of the method according to the invention. The sensor signal S6, which is provided by the one or more vehicle sensors 6 as described above, is transmitted to the receiving unit 29 or read in by the receiving unit 29 in a first control step SK1. Then, in a second control step SK2, the sensor signal S6 is evaluated in the control unit 30. The evaluation can be carried out, for example, as described above, by using the sensor signals S6 of the vehicle sensors 6; 6a, 6b, 6c, 6d, which optically detect an environment U, the distance D to a detected object is continuously determined, thereby making it plausible whether it can be a trailer 2.n or not. In a corresponding manner, an evaluation is carried out by monitoring the axle loads of the towing vehicle 1 measured by the axle load sensor 6e or the detection of a coupled trailer 2.n via the coupling sensor 6f in the coupling mouth of the automated towing device 43.

The control result 12 determined in the second control step SK2 then indicates, directly or indirectly as a function of the respective sensor signal S6, whether a trailer 2.n is coupled to the towing vehicle 1 or whether no trailer 2 is coupled to the towing vehicle 1. Depending on this control result 12, a braking strategy 18 is again selected in a third control step SK3, which is based on that shown in FIG Flow chart is a direct consequence of the control result 12. With the same effect, the control result 12 can already contain a braking strategy 18, which is selected based on whether a trailer 2.n, possibly of a specific trailer type Ti, was detected. The control result 12 is also in this case dependent on the presence or the detection of one or more trailers 2.n, possibly a specific trailer type Ti

When these control steps SK1, SK2, SK3 are carried out, it is assumed that there was no other way of reliably determining whether or not a trailer 2.n is coupled to the towing vehicle 1. This is the case, for example, if the trailer control device 39 with the trailer stability control system 39a has not given any corresponding feedback about its functionality, for example via a status signal S3 to the towing vehicle brake system 32, e.g. because the trailer control device 39 has a defect or is not supplied with energy or there is no electrical connection or a trailer control device 39 is not present in the respective trailer 2.n. The control steps SK1, SK2, SK3 therefore use the sensor signals S6 to check whether or not a coupled trailer 2.n is present.

If the control result 12 indicates, depending on the respective sensor signal S6, that a coupled trailer 2.n is present (12:y), this directly results in the selection of a first trailer braking strategy 18ga as the braking strategy 18, for example. In this selected first team braking strategy 18ga, depending on a present braking request 19 in the towing vehicle braking system 32, a towing vehicle control signal S1 for braking the towing vehicle 1 and also a pneumatic trailer control signal S2 for braking the trailer or trailers) 2.n generated, each taking into account that a trailer 2.n is present (determined from sensor signal S6), but this no or does not have a functional trailer stability control 39a (determined from the lack of feedback from the trailer 2.n or the lack of a status signal S3). The towing vehicle 1 and the trailer or trailers 2.n are therefore braked on the assumption that at least one trailer 2.n is coupled, but any instability that may occur cannot be compensated for via the trailer stability control or a trailer stability control 39a.

This can mean, for example, that in the first combination braking strategy 18ga, when there is a manually or automatically specified braking request 19, the (pneumatic) trailer control signal S2 is generated in the towing vehicle braking system 32 in such a way that lower or correspondingly limited control pressures are generated via the interface -Signal S7 are transmitted to the trailer 2.n. As a result, excessive braking interventions, which can possibly lead to locking of the wheels on trailer 2.n and which are otherwise controlled by trailer ABS control 39b, can be avoided from the outset. In addition, the towing vehicle control signal S1 can also be generated in the first combination braking strategy 18ga in such a way that a larger part of the braking request 19 is accepted by the towing vehicle 1 in order to be able to reduce the braking intervention on the trailer 2.n.

Furthermore, when a sensory determination is made that a stability-critical situation occurs on one of the trailers 2.n (outside the unavailable trailer RSC control 39c), for example, there is a risk of tipping over while cornering, after selecting the first combination braking strategy 18ga a corresponding towing vehicle control signal S1 or trailer control signal S2 is generated by the towing vehicle braking system 32, with which this instability is suppressed. In the first combination braking strategy 18ga, a “redundant” stability function in the towing vehicle 1 (based on sensory estimates) can generate a stabilizing braking request 19s, as a function of which the braking request 19 is specified and which results in a corresponding towing vehicle control signal S1 or trailer control signal S2 in order to ensure stability of the trailer 2.n and/or also the towing vehicle 1, and which assumes that in trailer 2.n no trailer stability control 39a is available. The stabilizing braking request 19s can here be determined, for example, as a function of the sensor signals S6 of the vehicle sensors 6, via which an unstable situation can be recognized or predicted or suspected.

According to an extended version, when selecting the first combination braking strategy 18ga, it can also be assumed that the trailer braking system 33 itself is not or cannot be controlled, i.e. no trailer control signal S2 is generated either, because, for example, the pneumatic Communication with the respective trailer 2.n is disturbed. Accordingly, stable braking is to be ensured solely via the towing vehicle 1 . However, this is more of a special case, since normally at least the pneumatic path is available via the trailer interface 7.

It is preferably additionally provided that the towing vehicle control signal S1 and the trailer control signal S2 are generated in the first team strategy 18ga as a function of further information, for example as a function of a number N of recognized trailers 2.n and/or one recognized Trailer type Ti of the coupled trailer(s) 2.n. This additional information can also be determined based on the sensor signals S6 of the respective vehicle sensors 6 who the. For example, a camera 6b can be used to draw conclusions about the number N of trailers 2.n but also about the trailer type Ti, eg the trailer loading condition AZ (empty, half full, full), the location of a trailer focus AS, the Number of axles AN, trailer construction AK (e.g. semi-trailer AK1, drawbar trailer AK2, ...), etc., are towed. Structural properties of a trailer 2.n can also be estimated via the additional optical vehicle sensors 6.

Thus, with a recognized trailer 2.n, which can be a semi-trailer AK1 or a drawbar trailer AK2, for example, which also has a known number of axles AN of, for example, “two” and a high trailer center of gravity AS when the trailer is fully loaded AZ , A coordinated control of the towing vehicle brake system 32 via a correspondingly generated towing vehicle control signal S1 and the trailer braking system 2.n via a pneumatic trailer control signal S2 generated in the towing vehicle braking system 32, which differs from an activation of a recognized unladen trailer 2.n with a low trailer center of gravity AS and a number of axles AN of “three”.

Thus, in the first combination braking strategy 18ga, based on the sensor-detected trailer type T.i and the associated attributes, starting from the towing vehicle braking system 32, braking for the entire combination can be specified, taking into account a non-existent or non-functional trailer stability control 39a , in which a stable ride can still be ensured.

In a second combination braking strategy 18gb, explained later, a towing vehicle control signal S1 and a trailer control signal S2 can also be generated in the towing vehicle braking system 32, provided that the trailer stability control system 39a is fully functional. In this variant, when the control signals S1, S2 are generated, it can be assumed that the stability controls 35a, 39a are fully functional, so that the full braking potential can be exploited. However, as soon as the lack of a status signal S3 from the relevant trailer 2.n and the control of the sensor signal S6 is detected was that in one of the existing trailers 2.n no trailer stability control 39a is available, the braking strategy or the control signals S1, S2 are adjusted accordingly to this circumstance (selection of the first combination braking strategy 18ga). In this way, the full braking potential can be exploited and safe ferry operations can be guaranteed.

If the control result 12, depending on the respective sensor signal S6, indicates that there is no coupled trailer 2.n (12:n), this directly results in the selection of a towing vehicle braking strategy 18z. In this selected towing vehicle braking strategy 18z, the towing vehicle control signal S1 for braking the towing vehicle 1 is generated independently of a specific trailer driving behavior or possible driving dynamics FD of a trailer 2.n, since it is assumed that no such trailer 2.n is present is. Therefore, the full braking potential of the towing vehicle 1 can be exploited, since no consideration for a possible instability of the (non-existent) trailer 2.n has to be taken (assuming the towing vehicle stability control 35a is functional). This is comparable to the second combination braking strategy 18gb (see below), in which it is assumed that the trailer or trailers 2.n coupled are each operated with a functioning trailer stability control system 39a.

Following the selection of the braking strategy 18, in a fourth control step SK4, if a braking request 19 is present, the selected braking strategy 18 is implemented by activating the towing vehicle braking system 32 with the towing vehicle control signal S1 generated as a function of the selected braking strategy 18 and the trailer braking system 33 with the generated as a function of the selected braking strategy 18 (pneumatic) trailer control signal S2. The braking request 19 can, for example, be presented manually by the driver via the operating element B, for example the brake pedal. or automatically by the brake request signal SB, as received from a system in the vehicle (XBR; ACC; RSC, etc.) or, for example, depending on the stabilizing brake request 19s from a "redundant" stability control in the first combination braking strategy 18ga is generated.

FIG. 3 shows a further flow chart of an exemplary embodiment of the method according to the invention, which is based on a method of the prior art and expands it accordingly. In the exemplary embodiment described, a trailer detection unit 24, which is designed in the form of software or a flardware unit, uses electrical and/or pneumatic data transmitted via the trailer interface 7 in a first detection step SE2 in a second detection step SE2 and/or hydraulic interface signals S7 detects whether a trailer 2 is coupled to the towing vehicle 1 or not. In this case, the number N of trailers 2.n present or should be present can also be detected, for example, using the intersection signals S7.

When proceeding according to FIG. 3, it can be assumed, for example, that the trailer(s) 2.n that can be coupled or are coupled have an electronically operated trailer brake system 33, preferably with a trailer brake system. Stability control 39a, in particular trailer ABS control 39b. In that case, an electronic data exchange between the towing vehicle braking system 32 and the trailer braking system 33 of one or more (number N) trailers 2.n can take place via an IS011992 or a PLC interface.

Via the trailer interface 7, the trailer detection unit 24 can then, for example, transmit an electrical status signal S3 as an interface signal S7. Is a trailer 2.n with a functioning electronic trailer braking system 33, in particular a functioning one Trailer control device 39 including trailer stability control 39a, coupled to the towing vehicle 1, the electrical status signal S3 can be transmitted without further interference between the towing vehicle 1 and the respective trailer 2.n, which is detected by the trailer detection unit 24 in the second Step SE2 can be determined. Similarly, the status signal S3 can also be a pneumatic or hydraulic signal that is modulated accordingly and whose successful transmission to the trailer 2.n can also be determined in the second detection step SE2, for example via a pressure sensor in the flow path or behind trailer interface 7.

If it is detected in the second detection step SE2, depending on the respective status signal S3, that a trailer 2.n is coupled and the trailer control device 39 including trailer stability control 39a is functional or available, this is indicated in a detection Result 23 output (23: y) and in a third detection step SE3, the second combination braking strategy 18gb is selected. The third detection step SE3, in which a braking strategy 18 is selected, coincides in the embodiment shown in FIG. 3 with the third control step SK3 according to the method sequence in FIG. 2, which, as will be explained later, is also used here . The detection result 23 indicates whether or not a trailer 2.n was detected by the trailer detection unit 24 using the interface signals S7, in particular the electrical status signal S3. In contrast to the control result 12, the recognition result 23 is thus generated as a function of a signal which is fed to the trailer interface 7 for the relevant trailer 2.n and, with a trailer 2.n coupled, as an interface signal S7 via the trailer Interface 7 is transmitted.

The selected second combination braking strategy 18gb assumes that both the towing vehicle 1 and the coupled trailer 2.n a functioning braking system is present, in which a stability control 35a, 39a is present and functional, so that the towing vehicle 1 and the trailer 2.n can be braked in a coordinated manner so that any instabilities that occur are controlled by the respective stability control 35a, 39b can be corrected. The towing vehicle control signal S1 and the trailer control signal S2 can therefore be generated in the second combination braking strategy 18gb in such a way that the full braking potential can be exploited.

If, in the second detection step SE2, it is detected, for example based on a status signal S3 that is output or returned by the trailer brake system 33, which is transmitted as an interface signal S7 via the trailer interface 7, that a trailer 2.n is indeed coupled, However, if the electronic trailer braking system 33, e.g. the trailer stability control 39a, in particular the trailer ABS control 39b, has a defect X, this is output in the recognition result 23 (23: X) and in the third detection step SE3, the first combination braking strategy 18ga described above is selected. In this case, the towing vehicle 1 and the respective trailer 2.n are braked under the assumption that possible instabilities are already taken into account in advance when the towing vehicle control signal S1 and the trailer control signal S2 are generated, since the trailer stability control 39a can no longer take on this task. Here, too, a number N of trailers 2.n and/or a recognized trailer type T.i can be taken into account.

If the evaluation of the status signal S3, in particular an electrical status signal S3, in the second detection step SE2 shows that no trailer 2.n is present (23: n), this is output in the detection result 23, whereupon the towing vehicle braking strategy 18z described above could be selected in the third detection step SE3. The train- Vehicle brake system 1 would therefore be activated under the assumption that there is no trailer 2.n or that no consideration is to be given to a non-existent or non-functional trailer control device 39 or trailer stability control system 39a. However, with the procedure described, it cannot be said with sufficient certainty whether the selection of the towing vehicle braking strategy 18z by the trailer detection unit 24 is reliable, since, for example, a connecting cable or hoses of a trailer 2.n that is actually coupled are not plugged in or are disconnected again In this case, the trailer detection unit 24 can deliver an incorrect detection result 23, since in this case there is also no status signal S3 that can be evaluated. Furthermore, a coupled trailer 2.n could be present without an electrical trailer control device 39 or without a trailer stability control system 39a, in which case at least no electrical status signal S3 would be present either. Choosing a towing vehicle braking strategy 18z that does not take into account a trailer 2.n that is not fully functional or is present could therefore lead to the trailer 2.n or the entire trailer swerving or unstable driving behavior.

In order to counteract this uncertainty, the first trailer-trailer braking strategy 18ga is normally selected in the prior art in the event that no trailer 2.n is detected, as indicated by the dashed line in FIG. This means that a vehicle 3, consisting of a towing vehicle 1 and a trailer 2.n that is not recognized by the trailer detection unit 24, is braked in the same way as a vehicle 3, which consists only of a towing vehicle 1 and is therefore actually driven by the towing vehicle -Braking strategy 18z could be braked. However, this means that braking potential is lost. Therefore, according to the exemplary embodiment shown in FIG. 3, an extended trailer identification is carried out in parallel via the control unit 30, which is based on the method described for FIG 24 to be checked or checked and therefore to be able to fall back on the full potential when braking and not to incorrectly select the first combination braking strategy 18ga instead of the towing vehicle braking strategy 18z.

If the trailer detection unit 24 does not actively detect a coupled trailer 2.n based on the respective status signal S3, then before the selection of a braking strategy 18 in the third detection step SE3 or in the third control step SK3, that shown in FIG Implementation example of the method according to the invention carried out. Only when the evaluation of the sensor signal S6 indicates that no trailer 2.n is actually coupled is the towing vehicle braking strategy 18z selected in the third detection step SE3 or in the third control step SK3 and otherwise the first combination -Braking strategy 18ga, in which a towing vehicle control signal S1 for braking the towing vehicle 1 as well as a pneumatic trailer control signal S2 for braking the trailer(s) 2.n is generated depending on an existing braking request 19 in the towing vehicle braking system 32 , each of which takes into account that although a trailer 2.n is present (determined from sensor signal S6), it has no trailer stability control system 39a, or no functioning trailer stability control system 39a (e.g. determined from a lack of feedback from trailer 2.n or missing status signal S3). Finally, in a fourth detection step SE4 or the fourth control step SK4, the towing vehicle brake system 32 is actuated with the corresponding towing vehicle control signal S1 and the trailer brake system 33 is actuated with the corresponding (pneumatic) trailer control signal S2. Such a constellation arises, for example, when a trailer 2.n is coupled to the towing vehicle 1, the trailer detection unit 24 is based on electrical and/or pneumatic and/or hydraulic interface signals S7 transmitted via the trailer interface 7 However, the required plug connection of the trailer interface 7 is not plugged in. As a result, initially no trailer 2.n is detected by the trailer detection unit 24, and due to a missing electrical plug connection (electrical status signal S3), it can then also be assumed that the trailer control device 39 with the trailer stability control 39a is not available stands. However, the trailer(s) 2.n can subsequently be recognized by means of the evaluation based on the sensor signal S6, as described for FIG. In this constellation, it was checked, so to speak, by means of two independent signals, the sensor signals S6 and the interface signals S7 transmitted via the trailer interface 7, that no trailer 2.n is actually coupled, so that there is a risk of an incorrect selection of braking strategy 18 is minimized or eliminated.

FIG. 4 shows an example of a comparison routine. Here, the control result 12 of the control unit 30 determined according to the invention, based on the sensor signal S6, is compared with the detection result 23 of the trailer detection unit 24, based on the intersection signal S7, and a corresponding comparison result 15 is provided. In the present example, the check result 12 can only consist of whether a coupled trailer 2.n was determined based on the sensor signal S6 (y) or not (n). The recognition result 23 of the trailer recognition unit 24 can consist of whether a coupled trailer 2.n was determined based on the intersection part signal S7 (y) or not (n) or whether there is a defect (X). The possibilities of the comparison and the braking strategies 18 resulting therefrom are shown in FIG. 4 in matrix form. If both the recognition result 23 of the trailer recognition unit 24 and the control result 12 of the control unit 30 determine a coupled, functioning and controllable trailer 2.n, in particular with a trailer control unit 39 and a trailer stability control system 39 (y , y), this leads to a first comparison result 15a, which indicates that both results 12, 23 are consistently positive (y, y). A fourth comparison result 15d is present when both results 12, 23 do not indicate any (n, n) followers 2.n, ie both are consistently negative (n, n).

If the recognition result 23 indicates a functional and controllable trailer 2.n (y), but the control result 12 does not (n), this leads to a second comparison result 15b, which indicates that the control result 12 deviates towards the negative (deviated negative (y, n)). If the detection result 23 indicates a defective trailer 2.n (X) and the control result 12 does not indicate a trailer 2.n (n), this also leads to the deviatingly negative second comparison result 15b (X, n).

If the recognition result 23 points to no trailer 2.n (n) and the control result 12 to a trailer 2.n (y), there is a third comparison result 15c, which indicates that the control result 12 is positive towards (n, y). If the detection result 23 points to a defective trailer 2.n (X) and the control result 12 to a trailer 2.n (y), this leads to a fifth comparison result 15e, which indicates that the results 12, 23 agree with regard to the fact that a trailer 2.n is present.

FIG. 4 also shows how the respective comparison result 15a, 15b, 15c, 15d, 15e influences the selection of braking strategy 18. In the present case, only the fourth comparison result 15d leads to the selection of a train vehicle braking strategy 18z. The towing vehicle braking strategy 18z is only selected if it has been checked by means of two independent signals S6 and S7 that no trailer 2.n is actually coupled to the towing vehicle 1. Otherwise, the first combination braking strategy 18ga (15b, 15c, 15e) is selected, which leads to activation of the brakes of the trailer 2.n via the trailer control signal S2 and of the towing vehicle 1 via the towing vehicle control signal S1, assuming that instabilities are not corrected by a trailer stability control 39a (corresponding braking force limitation for the trailer 2.n or "redundant" stability-controlled generation of a braking request 19), or the second combination braking strategy 18gb (15a) is selected which, comparable to the towing vehicle braking strategy 18z, can utilize the full braking potential, since it can be assumed that instabilities will be corrected via the trailer stability control 39a.

The respective comparison results 15a, 15b, 15c, 15d, 15e can additionally be output to a user interface 25, for example on a display. In particular, from the second comparison result 15b (differently negative) or the third comparison result 15c (differently positive), i.e. in the case of different results 12, 23 with regard to a coupled trailer 2.n, important information about the state of the vehicle 3 can follow.

List of reference symbols (part of the description)

1 towing vehicle

2.n trailer

3 vehicle

6 vehicle sensor

6a radar sensor

6b camera c Lidar sensor d Ultrasonic sensor e Axle load sensor f Coupling sensor of the automated trailer hitch 43g Articulation angle sensor system

Trailer interface 2 control result 5a first comparison result 5b second comparison result 5c third comparison result 5d fourth comparison result 5e fifth comparison result 8 braking strategy 8ga first combination braking strategy 8gb second combination braking strategy 8z towing vehicle braking strategy 9 braking request 9s stabilizing braking request 0a towing vehicle control line 0b trailer Control line 3 detection result 4 trailer detection unit 5 user interface 9 receiving unit 0 control unit 1 output unit 2 towing vehicle braking system 3 trailer braking system 4 vehicle braking system 5 towing vehicle control device 5a towing vehicle stability control 37 Towing vehicle brakes

39 trailer control device

39a trailer stability control

39b Trailer ABS control

39c Trailer RSC regulation

41 trailer brakes

43 automated hitch

AB trailer braking system type

AN number of axles

AK trailer construction

AK1 semi-trailer

AK2 drawbar trailer

AS trailer focus

AZ Trailer loading status

B Control

D Distance between towing vehicle 1 and trailer 2.n

FD driving dynamics of the trailer 2.n M number of trailer types n, i index N number of trailers 2.n

51 Towing vehicle control signal

52 trailer control signal

53 status signal

56 sensor signal

57 Interface signal SB Brake request signal T.i Trailer type U Area around the vehicle 3 X Defect

SK1 , SK2, SK3 control steps SE1 , SE2, SE3 detection steps

Claims

patent claims

1. A method for controlling a vehicle brake system (34) of a vehicle (3), wherein the vehicle (3) has at least one towing vehicle (1) and at least one trailer (2.n) can be coupled to the towing vehicle (1), wherein the towing vehicle (1) has a trailer interface (7), with interface signals (S7) being able to be transmitted via the trailer interface (7) between the towing vehicle (1) and at least one coupled trailer (2.n). at least the following steps:

- Reading in at least one sensor signal (S6) from at least one vehicle sensor (6) (SK1), the vehicle sensor (6) being formed to generate the sensor signal (S6) depending on whether at least one trailer ( 2.n) is coupled or not,

- Determining and providing a control result (12) by evaluating the sensor signal (S6) (SK2), the control result (12) indicating whether at least one trailer (2.n) to the towing vehicle (1) is coupled or not, the sensor signal (S6) and / or the control result (12) un depending on the interface parts signals (S7) is determined or who the acting on the trailer interface (7) and /or at least one coupled trailer (2.n) are transmitted via the trailer interface (7);

- Selecting a braking strategy (18) depending on the control result (12) and/or the sensor signal (S6) (SK3), the braking strategy (18) indicating how the vehicle braking system (34) of the vehicle (3 ) is controlled, and

- Control of the vehicle braking system (34) of the vehicle (3) depending on the selected braking strategy (18) in the presence of a ner braking request (19) (SK4).

2. The method according to claim 1, characterized in that the at least one sensor signal (S6) is provided directly or indirectly by a vehicle sensor (6), which is selected from the group consisting of: radar sensor (6a) and /or camera (6b) and/or lidar sensor (6c) and/or ultrasonic sensor (6d).

3. The method according to claim 1 or 2, characterized in that the at least one sensor signal (S6) from a vehicle sensor (6) is provided directly or indirectly, which is selected from the group consisting of: axle load sensor (6e) and / or Coupling sensor (6f) of an automated hitch (43) and/or articulation angle sensor system (6g).

4. The method according to any one of the preceding claims, characterized in that the at least one vehicle sensor (6) is arranged on the vehicle (3), in particular on the towing vehicle (1), and/or in the surrounding area (U) of the vehicle (3). is.

5. The method according to any one of the preceding claims, characterized in that as a braking strategy (18)

- a towing vehicle braking strategy (18z) is selected if the control result (12) indicates that no trailer (2.n) is coupled, or

- A first combination braking strategy (18ga) or a second combination braking strategy (18gb) is selected if the control result (12) indicates that at least one trailer (2.n) is coupled.

6. The method according to claim 5, characterized in that

- when selecting the first combination braking strategy (18ga). Towing vehicle control signal (S1) for braking the towing vehicle (1) and/or a trailer control signal (S2) for braking the at least one trailer (2.n) is generated as a function of an existing braking request (19) on the assumption that min at least one trailer (2.n) is coupled and the at least one coupled trailer (2.n) has no trailer stability control (39a) or no functional trailer stability control, or

- If the second combination braking strategy (18gb) is selected, a towing vehicle control signal (S1) for braking the towing vehicle (1) and/or a trailer control signal (S2) for braking the at least one trailer (2.n) depending on a present braking request (19) is generated on the assumption that at least one trailer (2.n) is coupled and the at least one coupled trailer (2.n) has a functional trailer stability control system (39a), or

- If the towing vehicle braking strategy (18z) is selected, a towing vehicle control signal (S1) for braking the towing vehicle (1) is generated as a function of a braking request (19) that is present, assuming that there is no trailer (2.n) is coupled and only the towing vehicle (1) is to be braked, with the towing vehicle control signal (S1) providing a towing vehicle braking system (32) in the towing vehicle (1) and the trailer control signal (S2) providing a trailer braking system (33) is controlled in the coupled trailer (2.n).

7. The method according to claim 6, characterized in that the towing vehicle control signal (S1) for braking the towing vehicle (1) and/or the trailer control signal (S2) for braking the min least one trailer (2.n). a selection of the first combination braking strategy (18ga) depending on a number (N) of recognized trailers (2.n) and/or depending on a trailer type (Ti) of a recognized trailer (2.n) is or are generated.

8. The method according to claim 7, characterized in that the number (N) of detected trailers (2.n) and/or the trailer type (T.i) is determined as a function of the sensor signal (S6) from at least one of the vehicle sensors (6). becomes.

9. The method according to claim 7 or 8, characterized in that the trailer type (T.i) of a trailer (2.n) is determined, for example, by a number of axles (AN) of the respective trailer (2.n) and/or a trailer construction (AK) of the respective trailer (2.n) and/or a trailer braking system type (AB) of the respective trailer (2.n) and/or a trailer center of gravity (AS) of the respective trailer (2.n) and/or a trailer Load status (AZ) is determined.

10. The method according to any one of claims 5 to 9, characterized in that the towing vehicle control signal (S1) for braking the towing vehicle (1) and/or the trailer control signal (S2) for braking the at least one trailer (2. n) upon selection of the towing vehicle braking strategy (18z) or the first combination braking strategy (18ga) or the second combination braking strategy (18gb) in the towing vehicle braking system (32) of the towing vehicle (1) it is generated in order to initiate a braking request (19 ) to implement, the trailer control signal (S2) being transmitted via the trailer interface (7) to the trailer brake system (33) in the trailer (2.n).

11. The method according to any one of claims 5 to 10, characterized in that the braking request (19) is specified and/or modified as a function of the selected braking strategy (18), the braking request (19) being Braking strategy (18ga) is specified and/or modified as a function of a stabilizing braking request (19s) in order to ensure stability of the towing vehicle (1) and/or the at least one coupled trailer (2nd .n) to worry.

12. The method as claimed in claim 11, characterized in that the stabilizing braking request (19s) is generated as a function of the sensor signal (S6) of at least one of the vehicle sensors (6).

13. The method according to any one of claims 5 to 12, characterized in that the control result (12) is compared with a detection result (23) from a trailer detection unit (24) and a comparison result (15) is provided, the braking strategy (18) is additionally selected as a function of the comparison result (15).

14. The method according to claim 13, characterized in that

- A first comparison result (15a) is provided as a comparison result (15) if both the control result (12) and the recognition result (23) indicate that a trailer (2.n) is coupled, or

- A second comparison result (15b) is provided as a comparison result (15) if the control result (12) does not indicate a coupled trailer (2.n) and the recognition result (23) of the trailer recognition unit (24) indicates a coupled one trailer (2.n) with or without the presence of a defect (X), or

- A third comparison result (15c) is provided as a comparison result (15) if the control result (12) indicates a coupled trailer (2.n) and the recognition result (23) of the trailer identification unit (24) indicates no coupled trailer (2.n) an- there, or

- A fourth comparison result (15d) is provided as a comparison result (15) if both the control result (12) and the recognition result (23) indicate that no trailer (2.n) is coupled, or

- A fifth comparison result (15e) is provided as the comparison result (15) if the control result (12) indicates that a trailer (2.n) is coupled and the recognition result (23) indicates a coupled trailer (2 .n) with a defect (X).

15. The method according to claim 14, characterized in that

- With the first comparison result (15a), the second combination braking strategy (18gb) is selected in order to implement the braking request (19), and/or

- With the fourth comparison result (15d), the traction vehicle braking strategy (18z) is selected in order to implement the braking request (19), and/or

- With the second comparison result (15b) or the third comparison result (15c) or the fifth comparison result (15e), the first combination braking strategy (18ga) is selected in order to implement the braking request (19).

16. The method according to any one of claims 13 to 15, characterized in that the control result (12) is determined in a control unit (30) independently of the recognition result (23) of the trailer recognition unit (24).

17. The method according to any one of claims 13 to 16, characterized in that the recognition result (23) is dependent on the interface signals (S7) which act on the trailer interface (7) and/or on a coupled trailer Followers (2.n) about the Trailer interface (7) are transmitted.

18. The method according to any one of claims 13 to 17, characterized in that the comparison result (15) is output to a user interface (25).

19. The method according to any one of the preceding claims, characterized in that the braking request (19) is specified manually via an operating control element (B) or automatically via a braking request signal (SB).

20. Towing vehicle (1) with a trailer interface (7), wherein at least one trailer (2) can be coupled to the towing vehicle (1) in such a way that interface parts signals (S7) via the trailer interface (7) between the towing vehicle (1) and the at least one coupled trailer (2.n) can be transferred, the towing vehicle (1) also having:

- At least one vehicle sensor (6) for generating a sensor signal (S6), wherein the vehicle sensor (6) is designed to generate the sen sor signal (S6) depending on whether at least one trailer (2.n) on the towing vehicle (1) is coupled or not,

- A control unit (30), the control unit (30) being set up to evaluate a generated sensor signal (S6) and to provide a control result (12) as a function thereof, the control result (12) indicating whether at least one trailer (2.n) is coupled to the towing vehicle (1) or not, the sensor signal (S6) and/or the control result (12) being determined independently of the interface signals (S7). can be NEN, which can act on the trailer interface (7) and / or at least one coupled trailer (2.n) can be transmitted via the trailer interface (7), and - A towing vehicle braking system (32) for braking the towing vehicle (1) depending on a braking request (19) and a braking strategy (18), the braking strategy (18) depending on the control result (12) and/or the sensor signal (S6) can be selected.