DE102022200975A1 - Method and control device for determining a clutch position of a clutch of a vehicle combination - Google Patents

Abstract

The approach presented here relates to a method for determining a coupling position of a coupling element (115) and/or a length of the coupling element (115), which is designed to connect a second vehicle part (110) to a first vehicle part (105) of a vehicle combination (100) to couple, the method using a step of reading in a bending angle (O) and an axle position (A) of at least one wheel axle (120) of the second vehicle part (110), a step of determining a length estimate for the length of the coupling element (115). the articulation angle (Θ) and at least one coordinate of the axle position (A), and a clutch position estimate of the clutch position using at least one further coordinate of the axle position (A) and the length estimate of the coupling element (115) and a step of outputting the clutch position estimate as a clutch position and/ or the estimated length as the length of the coupling element (115).

Description

State of the art

The approach is based on a method and a control device for determining a clutch position of a clutch of a vehicle combination according to the species of the independent claims. The subject of the present approach is also a computer program.

Driver assistance systems whose task is to monitor the lateral area of a vehicle (e.g. blind spot monitoring) should be able to actively deal with coupled trailers, since in the worst case this can lead to false warnings and thus to less acceptance of the system by the driver. While such a system can simply be deactivated for passenger car applications, the same procedure would be unthinkable for commercial vehicles. In order to be able to continue to guarantee the function of the assistance system for commercial vehicles, the presence of a trailer should be expected and dealt with.

The WO 2020/207572 A1 describes a method for determining a wheelbase of a vehicle trailer for a vehicle combination with a towing vehicle and the at least one vehicle trailer.

Disclosure of Invention

Against this background, with the approach presented here, an improved method for determining a clutch position of a clutch of a vehicle combination, an improved control unit that uses this method, and finally a corresponding computer program according to the main claims are presented. Advantageous developments and improvements of the device specified in the independent claim are possible as a result of the measures listed in the dependent claims.

A commercial vehicle offers a user many options for retrofitting and/or adaptation with regard to installed clutches and in particular with regard to their position on the vehicle chassis. Fifth wheel couplings that can be adjusted by the driver are common, as are retrofitted low or high couplings. These diverse possibilities mean that during operation it cannot be assumed that all installed couplings and/or the position of the couplings are known. Since the position of the hitch has a significant influence on the motion behavior of the trailer, precise knowledge of its position, as described in the approach presented, improves the quality of a kinematic model significantly. As a result, this leads to a better estimation of the position of the trailer or trailers and thus to fewer false reactions from an assistance system. At the same time, this can increase road safety for other road users.

A method for determining a coupling position of a coupling element and additionally or alternatively a length of the coupling element is presented, which is designed to couple a second vehicle part to a first vehicle part of a vehicle combination, the method including a step of reading in an articulation angle and an axle position at least a wheel axle of the second vehicle part, a step of determining a length estimate for the length of the coupling element using the articulation angle and at least one coordinate of the axle position, and a clutch position estimate of the clutch position using at least one further coordinate of the axle position and the length estimate of the coupling element and a step of Outputting the estimated value of the coupling position as the coupling position and/or the estimated value of the length as the length of the coupling element.

The method can be carried out, for example, for a vehicle combination that includes the first and the second vehicle part. The first part of the vehicle can be implemented as a towing vehicle, for example a truck. Correspondingly, the second vehicle part can be formed, for example, as a vehicle trailer. For example, the vehicle combination can have a plurality of vehicle trailers. The coupling element can be formed, for example, as a drawbar, which is connected to at least one wheel axle of the second vehicle part. The articulation angle can, for example, represent an angle by which an orientation of the second vehicle part can deviate relative to the first vehicle part. The coordinate of the axle position can be, for example, the connection point at which the center of an axle of the second vehicle part lies or a wheel of the second vehicle part is connected to the wheel axle. By determining the corresponding values, cornering can be made safer, for example, since a trajectory of the second vehicle part can be precisely reconstructed or predicted, for example. As a result, train drivers and/or other road users, for example, can be warned of dangerous situations at the same time.

According to one embodiment, in the step of determining, the length estimate and additionally or alternatively the clutch position estimate using a track width value of the second vehicle part can be determined. In particular, the lane width value can represent half a lane width of the second vehicle part. The lane width value can be used, for example, as an assumed value that can be based on a roadway that is currently being traveled on, merely by way of example. Alternatively, the lane width value can be stored in a memory unit, for example, or can be determined using sensor data, for example. In particular, half the track width value can represent, for example, a distance between the coupling point of the wheel with the wheel axle and the coupling element.

The method may include a step of providing the articulation angle and the axle position before the reading step, wherein the axle position can be estimated using a distance sensor, and wherein the articulation angle using the estimated axle position, an assumed coupling position and an assumed length of the coupling element as well can additionally or alternatively be estimated using, for example, a static or dynamic vehicle motion parameter. The distance sensor can be formed, for example, as a radar sensor, a lidar sensor, a camera or, for example, as an ultrasonic sensor. The distance sensor can be configured to detect a distance from the distance sensor to the axle position. The vehicle's own movement parameter can represent vehicle-specific data, for example, such as speed values, braking torques, steering angle, effective wheelbase or acceleration values.

According to one embodiment, the articulation angle can be provided in the step of providing, in particular by a model or a direct measurement by a sensor such as a potentiometer, a lidar system, a radar system or the like, which can be obtained using the vehicle's own motion parameter, which can represent a speed and additionally or alternatively a yaw rate of the second vehicle part and/or the first vehicle part. Advantageously, the vehicle's own movement parameter can be detected using the distance sensor. Alternatively, the vehicle's own movement parameter can also be detected, for example, using a sensor unit that is installed in the vehicle anyway.

Furthermore, the steps of the method can be carried out repeatedly, it being possible for the estimated clutch position value to be used as the assumed clutch position and the estimated length value to be used as the assumed length in a step of providing which is carried out repeatedly. A new reference value can advantageously be generated in this way, on the basis of which the repeated steps of the method can be carried out. In this way, a regular check can advantageously be carried out, which means for example at defined time intervals.

According to one specific embodiment, in the determination step, the estimated length and additionally or alternatively the estimated clutch position can be determined using an estimated length determined in a previous determination step and additionally or alternatively an estimated clutch position. Advantageously, the corresponding values, ie the length estimate and additionally or alternatively the clutch position estimate, can be updated as a result.

Furthermore, a (for example mathematical) filter or an estimation method, in particular a filter from the group of Kalman filters or a maximum likelihood filter, can be used in the determination step in order to obtain a quality of the estimated clutch position value and the estimated length value. Advantageously, the length estimate and additionally or alternatively the clutch position estimate as well as the length estimate determined in a previous determination step and additionally or alternatively the previously determined clutch position estimate can be used as input parameters for the filter.

Furthermore, the method can include a step of checking whether the length estimate and additionally or alternatively the clutch position estimate, in particular each, meet a predetermined criterion, it being possible for the steps of the method to be carried out repeatedly if the criterion, in particular for the length estimate and/or for the clutch position estimate, is not met. The criterion can be defined, for example, as a deviation from an estimated length value and/or estimated clutch position value determined in a previous determination step, which deviation cannot amount to more than 10%, for example. Using the criterion, for example, a quality of the estimated value of the clutch position can be determined, by means of which, for example, a repetition or an end of the method can be determined.

According to one embodiment, the steps of the method can be repeated as long as the criterion is not met. Additionally or alternatively, the process can be ended if the specified criterion is met. Advantageously, it can thereby be regularly checked whether the criterion is met.

Furthermore, in the step of reading in, the articulation angle and additionally or alternatively the axle position can be read in, which can be determined in a sensor-specific manner, for example by means of additional speed information. This speed information can be obtained, for example, as micro-Doppler information or from an optical flow, for example from a camera system.

The sensor-specific determination of the axle position can include a determination of micro-Doppler information based on distance data, in particular radar data, determined by means of the distance sensor, in particular a radar sensor. A position and/or number of wheels of the second vehicle part, in particular the axle position, can be determined on the basis of the micro-Doppler information. Due to the rotation of the rims, areas of the rims move towards the radar sensor and other areas move away from the radar sensor. This typical speed distribution can be recognized using the micro-Doppler effect, so that the position of the wheels or the axle position can be determined exactly. The micro-Doppler effect for radar data or radar signals is known, see for example the publication by Victor Chen et al.: "Micro-Doppler Effect in Radar: Phenomenon, Model, and Simulation Study" in IEEE Transactions on Aerospace and Electronic Systems, Vol 42, No. 1, January 2006.

This method can be implemented, for example, in software or hardware or in a mixed form of software and hardware, for example in a control unit.

The approach presented here also creates a device that is designed to carry out, control or implement the steps of a variant of a method presented here in corresponding devices. The object on which the invention is based can also be achieved quickly and efficiently by this embodiment variant of the invention in the form of a device.

For this purpose, the device can have at least one computing unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or an actuator for reading in sensor signals from the sensor or for outputting data or control signals to the Have actuator and / or at least one communication interface for reading or outputting data that are embedded in a communication protocol. The arithmetic unit can be, for example, a signal processor, a microcontroller or the like, with the memory unit being able to be a flash memory, an EEPROM or a magnetic memory unit. The communication interface can be designed to read in or output data wirelessly and/or by wire, wherein a communication interface that can read in or output wire-bound data can, for example, read this data electrically or optically from a corresponding data transmission line or can output it to a corresponding data transmission line.

In the present case, a device can be understood to mean an electrical device that processes sensor signals and, depending thereon, outputs control and/or data signals. The device can have an interface that can be configured as hardware and/or software. In the case of a hardware design, the interfaces can be part of a so-called system ASIC, for example, which contains various functions of the device. However, it is also possible for the interfaces to be separate integrated circuits or to consist at least partially of discrete components. In the case of a software design, the interfaces can be software modules which are present, for example, on a microcontroller alongside other software modules.

A computer program product or computer program with program code, which can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and for carrying out, implementing and/or controlling the steps of the method according to one of the embodiments described above, is also advantageous is used, in particular if the program product or program is executed on a computer or a control device.

• 1 eine schematische Darstellung eines Fahrzeugverbunds in dem eine Vorrichtung gemäß einem Ausführungsbeispiel verwendet wird;
• 2 eine schematische Darstellung eines Fahrzeugverbunds in dem eine Vorrichtung gemäß einem Ausführungsbeispiel verwendet wird;
• 3 ein Ablaufdiagramm eines Verfahrens gemäß einem Ausführungsbeispiel zum Bestimmen einer Kupplungsposition des Kopplungselements und/oder einer Länge des Kopplungselements;
• 4 ein Ablaufdiagramm eines Ausführungsbeispiels eines Verfahrens zum Bestimmen einer Kupplungsposition des Kopplungselements und/oder einer Länge des Kopplungselements;
• 5 ein Blockschaltbild einer Vorrichtung gemäß einem Ausführungsbeispiel; und
• 6 eine schematische Darstellung erfasster Detektionen zur Verwendung in einem Ausführungsbeispiel des hier vorgestellten Ansatzes.

Exemplary embodiments of the approach presented here are shown in the drawings and explained in more detail in the following description. It shows:

• 1 a schematic representation of a vehicle network in which a device according to an embodiment is used;
• 2 a schematic representation of a vehicle network in which a device according to an embodiment is used;
• 3 a flow chart of a method according to an embodiment for determining a coupling position of the coupling element and/or a length of the coupling element;
• 4 a flowchart of an embodiment of a method for determining a coupling position of the coupling element and/or a length of the coupling element;
• 5 a block diagram of a device according to an embodiment; and
• 6 a schematic representation of detected detections for use in an embodiment of the approach presented here.

In the following description of favorable exemplary embodiments of the present approach, the same or similar reference symbols are used for the elements which are shown in the various figures and have a similar effect, with a repeated description of these elements being dispensed with.

1 FIG. 1 shows a schematic representation of a vehicle assembly 100 in which a device according to an exemplary embodiment is used. The vehicle assembly 100 has a first vehicle part 105 and a second vehicle part 110 which are connected to one another by means of a coupling element 115 . The vehicle combination 100 is also referred to as a vehicle combination, for example, which has a towing vehicle and, for example, a vehicle trailer. According to this exemplary embodiment, the first vehicle part 105 is in the form of a towing vehicle and the second vehicle part 110 is in the form of a vehicle trailer. The first vehicle part 105 is formed, for example, as a truck or, for example, as a utility vehicle. A commercial vehicle is also implemented as a tractor or a construction machine, for example. The coupling element 115 is realized, for example, as a vehicle drawbar, which is coupled to at least one wheel axle 120 of the second vehicle part 110, for example. According to this exemplary embodiment, the vehicle network 100, in particular the first vehicle part 105, has a device 125 which is designed to carry out or control a method for determining a coupling position of the coupling element and/or a length of the coupling element 115. For this purpose, in addition to a detected axle position A, a bending angle Θ and optionally a vehicle movement parameter 127 are used. The device 125 is formed, for example, as a control device or as part of a control device. Furthermore, the vehicle assembly 100, more precisely the first vehicle part 105, has at least one distance sensor 130, which is designed to detect distances within a surrounding area 135 of the vehicle assembly 100, such as a coordinate of the axle position A of the at least one wheel axle 120.

2 FIG. 1 shows a schematic representation of a vehicle assembly 100 in which a device according to an exemplary embodiment is used. The vehicle network 100 is similar to that in FIG 1 described vehicle network 100. According to this embodiment, only for the in 3 described method determined and / or given sizes shown graphically. The method is used to calculate a length estimate L for the length of the coupling element using a kink angle Θ and at least one coordinate of the axis position A and/or a coupling position 200, which means an estimated coupling position value K of the coupling element using at least one other coordinate of the axis position and the length estimate L of the coupling element is determined. The length of the coupling element, or the estimated length value L, is also referred to as the element length L, for example. Furthermore, a track width, in particular half a track width, is taken into account in the method, which is included as a track width value B in the method. Half the track width is assumed, for example, with the track width value B suitable for the application.

In other words, the approach presented enables an evaluation of sensor data, for example from a radar sensor, which was previously also described as a distance sensor, using a clutch position estimate for radar-based driver assistance systems for commercial vehicles, for example. Such a sensor provides position and speed data. In the present approach, position and in particular the speed data are used, in particular the micro-Doppler information, in order to detect the location of the axle packages of the trailer. There is a clear geometric relationship between the axle package and the coupling position, which makes it possible to estimate the coupling position.

The algorithm described below is executed cyclically, for example, as soon as new data from the radar sensor is available. For example, a motion model of the axle package is updated with the current vehicle motion parameters and an initially assumed clutch position as well as an assumed estimated length value L, so that the position estimate and radar data coincide in time, which is also referred to as prediction. Then the radar data of the prediction of the axis package position assigned, which is called an association. In the next step, the clutch position is estimated using the radar detections associated with the axle package. This estimate uses the in 2 illustrated mathematical relationship from:

With wheelbase and/or element length L, half the track width B, coupling position K, articulation angle Θ and the axle position A, with the articulation angle Θ being the result of the calculated model, with the estimated angle Θ depending, among other things, on the parameters K and L to be determined . To estimate the clutch position, the axis position is also described as a function of these parameters: $$\text{A}=\left(\begin{array}{c}-\text{K}-\text{L}\cdot \text{cos}\left(\mathrm{\theta }\right)-\text{B}\cdot \text{sin}\left(\mathrm{\theta }\right)\\ -\text{L}\cdot \text{sin}\left(\mathrm{\theta }\right)+\text{B}\cdot \text{cos}\left(\mathrm{\theta }\right)\end{array}\right)=\left(\begin{array}{c}{\text{A}}_{\text{x}}\\ {\text{A}}_{\text{y}}\end{array}\right)$$

wobei A_y die y-Komponente der Achsposition entspricht, welche durch die Auswertung der Radardaten gewonnen wird. Die halbe Spurbreite B kann mit einem für den Anwendungsfall geeigneten Wert angenommen werden, wobei 1,275m für die allermeisten im Straßenverkehr befindlichen Anhänger eine gute Wahl darstellen sollte. Die Kupplungsschätzung erfolgt gemäß diesem Ausführungsbeispiel daraufhin durch: $$\widehat{\text{K}}=-{\text{A}}_{\text{x}}-\widehat{\text{L}}\cdot \text{cos}\left(\mathrm{\theta }\right)-B\cdot \text{sin}\left(\mathrm{\theta }\right)$$

wobei A_x der x-Komponente der Achsposition entspricht, welche durch die Auswertung der Radardaten gewonnen wird. Die Aktualisierung der Kupplungspositionsschätzung sowie der Elementlänge erfolgt im Anschluss daran. Dabei legt die zusätzliche Abschätzung der momentanen Unsicherheit der Parameter die Nutzung eines Filters nahe.Since the coupling position is always positioned in the middle of the vehicle, it only has an x-component. For example, the element length L is estimated by: $$\widehat{\text{L}}=\frac{\text{B}\cdot \text{cos}\left(\mathrm{\theta }\right)-{\text{A}}_{\text{y}}}{\text{sin}\left(\mathrm{\theta }\right)}$$

where A _y corresponds to the y-component of the axis position, which is obtained by evaluating the radar data. Half the track width B can be assumed to be a value suitable for the application, with 1.275 m being a good choice for most trailers on the road. According to this exemplary embodiment, the clutch is then estimated by: $$\widehat{\text{K}}=-{\text{A}}_{\text{x}}-\widehat{\text{L}}\cdot \text{cos}\left(\mathrm{\theta }\right)-B\cdot \text{sin}\left(\mathrm{\theta }\right)$$

where A _x corresponds to the x-component of the axis position, which is obtained by evaluating the radar data. The coupling position estimate and the element length are then updated. The additional estimation of the momentary uncertainty of the parameters suggests the use of a filter.

If the clutch position is estimated, for example, with a quality that is appropriate for the application, the estimation process is completed. If the quality is not sufficient, the process is repeated until the termination criterion is reached.

A convergence towards the actual clutch position K is achieved by this iterative execution. This also results in estimated values for the element length L and the kink angle Θ. The estimation of the clutch position does not necessarily follow the pattern shown, but in any case uses the clear geometric relationship.

3 FIG. 3 shows a flow chart of a method 300 according to an embodiment for determining a coupling position of the coupling element and/or a length of the coupling element. The method 300 is carried out or controlled for a vehicle combination, as is the case, for example, in one of 1 until 2 was described. The method 300 comprises a step 305 of reading in, a step 310 of determining and a step 315 of outputting. In step 305 of reading in, an articulation angle and an axle position of at least one wheel axle of the second vehicle part are read in. In step 310 of determination, a length estimate for the length of the coupling element is determined using the articulation angle and at least one coordinate of the axis position. Furthermore, in step 310 an estimated value of the coupling position is determined using at least one further coordinate of the axis position and the determined estimated length of the coupling element. In step 315 of outputting, the estimated value of the coupling position is output as the coupling position and/or the estimated length value is output as the length of the coupling element.

Merely optionally, the method 300 comprises a step 320 of providing the articulation angle and the axle position before the step 305 of reading in, the axle position being estimated using a distance sensor, as is only shown by way of example in FIG 1 was described. In addition, the articulation angle is estimated using the estimated axle position, an assumed coupling position and an assumed length of the coupling element and/or using a vehicle's own motion parameter. The vehicle's own movement parameter represents, for example, vehicle-specific data or values. For example, the vehicle's own motion parameter represents a speed and/or a yaw rate of the second vehicle part. In a checking step 325, it is checked whether the length estimate and/or the clutch position estimate meets a predetermined criterion. According to this exemplary embodiment, steps 305, 310, 315, 320, 325 of method 300 are carried out repeatedly if the criterion is not met. This means that the method 300 is repeated as long as the criterion is not met. On the other hand, the method 300 is ended when the predefined criterion is met. In this case, for example, in a repeatedly executed step of providing the clutch position estimated value as the assumed clutch position and the lengths estimated value is used as the assumed length and thus a new reference value is generated.

According to this exemplary embodiment, the articulation angle and/or the axle position in step 305 of reading in is only optionally read in using speed information that is determined, for example, as wheel-specific micro-Doppler information or as information from an optical flow obtained by means of a camera system. In step 310 of the determination, the length estimate and/or the clutch position estimate is also optionally determined using a track width value of the second vehicle part, which represents half a track width, for example. Furthermore, for example, the estimated length and/or the estimated clutch position is determined using an estimated length and/or estimated clutch position determined in a previous step 310 of determination, which act, for example, as base values for updating the values to be determined. For example, in step 310 of determining, a Kalman filter is used to obtain a quality of the clutch position estimate and the length estimate. For example, the length estimate and/or the clutch position estimate and the length estimate and/or clutch position estimate ascertained in a previous step 310 of the determination are used as input parameters for the Kalman filter.

4 shows a flow chart of an embodiment of a method 300 for determining a coupling position of the coupling element and/or a length of the coupling element. For example, the method 300 corresponds or is similar to that in 3 described method 300 and is described in other words according to this exemplary embodiment. In addition, step 320 of providing according to this exemplary embodiment deviates from that in FIG 3 described step 320 that it comprises a first sub-step 400, a second sub-step 405 and a third sub-step 410.

In the first sub-step 400, for example, a vehicle speed value, that is to say for a vehicle's own movement parameter, is provided for carrying out the second sub-step 405. In second sub-step 405, the vehicle speed value provided in first sub-step 400 is read into a predefined model for, for example, a first axle assembly of the second vehicle part, resulting in the articulation angle, for example, which is used further in subsequent step 305 of method 300. In the third partial step 410, for example, the data recorded by the distance sensor is provided as axis position data, which is also used further in the subsequent step 305 of the method 300. In step 305 of reading in, for example, the axle position data that have been read in, which are also generally referred to below as radar data, are associated with the axle package modeled in second partial step 405 . Using this association, a new estimated value for a coupling position and a length of the coupling element is generated in step 310 of determination. The corresponding values, ie the clutch position estimate and the length estimate, are optionally updated and/or an uncertainty of the values is estimated. Finally, in step 325 of checking, a check is made as to whether or not the termination criterion is met. If the criterion is not met, the steps 320, 305, 310, 315, 325 of the method 300 are repeated and/or executed in a different order than the one described.

5 12 shows a block diagram of a device 125 according to an embodiment. The device 125 can be used, for example, for a vehicle network, as is the case, for example, in 1 has been described, and is designed, for example, to control or carry out a method for determining a coupling position of the coupling element and/or a length of the coupling element, as is the case, for example, in at least one of 3 until 4 was described. For this purpose, according to this exemplary embodiment, the device 125 has a reading unit 500 , a determination unit 505 and an output unit 510 . The reading unit 500 is designed to read in an articulation angle Θ and an axle position A of at least one wheel axle of the second vehicle part. Determination unit 505 is designed to calculate the estimated length L for the length of the coupling element using the articulation angle Θ and at least one coordinate of the axis position A, and the estimated coupling position value K of the coupling position using at least one further coordinate of the axis position A and the estimated length L of the coupling element determine. The output unit 515 is designed to output the estimated clutch position value K as the clutch position and the estimated length value L as the length of the coupling element.

6 shows a schematic representation of detected detections for use in an embodiment of the approach presented here. In the 6 The detections shown are only to be understood as exemplary values that were recorded, for example, with laterally installed distance sensors, such as radar sensors, on a semi-trailer truck with a trailer attached. The algorithm described was proto typically implemented. A cycle comprising a radar sensor (0), a clutch position (1) which is opposite an origin in (0,0) and an estimated axle position (2) is therefore shown by way of example only. The points 600 represent the detections of the radar sensor (0) and their arrows 605 an indication of a measured speed (related to the sensor coordinate system). The connecting lines 607 represent detections of the radar sensor (0) associated with the axis position, whereas the line 610 represents element length L.

If an embodiment includes an "and/or" link between a first feature and a second feature, this should be read in such a way that the embodiment according to one embodiment includes both the first feature and the second feature and according to a further embodiment either only that having the first feature or only the second feature.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2020207572 A1 [0003]

Claims (13)

Method (300) for determining a coupling position of a coupling element (115) and/or a length of the coupling element (115), which is designed to couple a second vehicle part (110) to a first vehicle part (105) of a vehicle combination (100), the method (300) comprising the steps of: - Reading in (305) a bending angle (O) and an axle position (A) of at least one wheel axle (120) of the second vehicle part (110); - Investigate (310) o a length estimate (L) for the length of the coupling element (115) using the articulation angle (Θ) and at least one coordinate of the axis position (A), and o a coupling position estimate (K) of the coupling position using at least one further coordinate of the axle position (A) and the determined length estimate (L) of the coupling element (115); and - Outputting (315) the estimated coupling position value (K) as the coupling position and/or the estimated length value (L) as the length of the coupling element (115). Method (300) according to claim 1 , wherein in step (310) of determining the length estimate (L) and/or the clutch position estimate (K) is determined using a track width value (B) of the second vehicle part (110), in particular wherein the track width value (B) is half a track width of the second Vehicle part (110) represents. Method (300) according to one of the preceding claims, with a step (320) of providing the articulation angle (O) and the axis position (A) before the step (305) of reading in, the axis position (A) being measured using a distance sensor (130 ) is estimated, and wherein the articulation angle (Θ) is estimated using the estimated axle position (A), an assumed coupling position and an assumed length of the coupling element (115) and/or using a vehicle's own motion parameter (127). Method (300) according to claim 3 , wherein in the step (320) of providing the articulation angle (O), in particular by a model or a direct measurement by a sensor, is provided, which is obtained using the vehicle's own motion parameter (127), which indicates a speed and/or a yaw rate of the second vehicle part (110) and/or the first vehicle part (105). Method (300) according to any one of claims 3 until 4 , wherein the steps (305, 310, 315, 320) of the method (300) are repeatedly executed, wherein in a repeatedly executed step (320) of providing the clutch position estimate (K) as the assumed clutch position and the length estimate (L) as the assumed length is used. Method (300) according to one of the preceding claims, wherein in the step (310) of determining the estimated length value (L) and/or the estimated clutch position value (K) using an estimated length value (L) and/or determined in a previous step (310) of determining or clutch position estimate (K) is determined. Method (300) according to claim 6 , A filter or an estimation method, in particular a Kalman filter, being used in step (310) of determining in order to obtain a quality of the estimated clutch position value (K) and the estimated length value (L). Method (300) according to claim 7 , comprising a step (325) of checking whether the length estimate (L) and/or the clutch position estimate (K) satisfies a predetermined criterion, wherein the steps (305, 310, 315, 320, 325) of the method (300) are repeatedly performed if the criterion is not met. Method (300) according to claim 8 , wherein the steps (305, 310, 315, 320, 325) of the method (300) are repeated as long as the criterion is not met, and/or wherein the method (300) is ended when the predetermined criterion is met . Method (300) according to one of the preceding claims, wherein in step (320) of reading in the articulation angle (O) and/or the axle position (A) are read in as wheel-specific micro-Doppler information. Device (125) set up to execute and/or control the steps (305, 310, 315, 320, 325) of the method (300) according to one of the preceding claims in corresponding units (500, 505, 510). A computer program comprising instructions which, when executed by a computer, cause the computer to perform the steps of the method (300) according to any one of Claims 1 until 10 execute and/or control. Machine-readable storage medium on which the computer program claim 12 is saved.

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