Method for estimating a trailer angle value, control unit and vehicle

Abstract

Method for estimating a trailer angle value for at least one trailer angle (φ) between a trailer (3, 14) and a towing vehicle (1) coupled to the trailer (3, 14), comprising the steps: - Providing a model (8, 13) of the towing vehicle (1) and the trailer (8, 13) coupled to the towing vehicle (1), wherein the model (8, 13) describes a dependence of the at least one trailer angle (φ) on one or more driving parameters of the towing vehicle (1), - Initializing at least one first instance (9) of the model (8, 13) with at least one first trailer angle start value and a second instance (10) of the model (8, 13) with at least one second trailer angle start value for the at least one trailer angle (cp), - Continuous reception of driving parameters of the towing vehicle (1) during its movement, - Continuous calculation of at least a first hypothesis (11) for the trailer angle (φ) with the first instance (9) of the model (8, 13) and of a second hypothesis (12) for the trailer angle (φ) with the second instance (10) of the model (8, 13), wherein the hypotheses (11, 12) are calculated on the basis of the driving parameters, - Continuous estimation of the pendant angle value depending on the hypotheses (9, 10) for at least one pendant angle (φ).

Description

[0001] The invention relates to a method for estimating a trailer angle value for at least one trailer angle between a trailer and a towing vehicle coupled to the trailer. The invention further relates to a control unit and a vehicle.

[0002] Automated and autonomous driving is becoming increasingly prevalent, particularly in the freight transport sector for trucks and other transport vehicles. For route planning of a vehicle combination consisting of a tractor unit and a trailer, determining the current angle between the two is necessary, as this angle varies during driving and its position significantly impacts the maneuverability and collision avoidance of the combination. Numerous methods exist for determining this angle, such as distance sensors on the tractor unit, sensors on the kingpin of a trailer hitch, or a rear-view camera on the tractor unit.

[0003] WO 2024 / 078 667 A1 describes a method in which, to provide a view of the surroundings, an area obscured by a trailer in an image from a reversing camera of the towing vehicle is replaced with image data from a camera on the trailer. The angle between the towing vehicle and the trailer is determined based on edges shown in the reversing camera image and the position of a coupling point of the trailer on the towing vehicle.

[0004] From EP 3 640 676 A1, a method is known in which the swivel angle of a sensor device mounted on a vehicle of a vehicle combination is adjusted as a function of an articulation angle between a towing vehicle and a trailer of the vehicle combination. The articulation angle is determined over time, starting from a straight-ahead position of the towing vehicle and the trailer, using a model of the vehicle combination.

[0005] US 2012 / 0185131A1 describes a method for the operation of a vehicle combination comprising a towing vehicle and a trailer. The angle between the towing vehicle and the trailer is determined by distance sensors mounted at the rear of the towing vehicle.

[0006] DE 10 2018 122 273 A1 describes a method for determining unstable behavior of a trailer in a vehicle combination, where the vehicle combination has N links, one of which is formed by a towing vehicle and at least one other link by the trailer. For this purpose, the current driving dynamics of the trailer are first recorded directly via sensors on the trailer. Simultaneously, the ideal behavior of the trailer is calculated based on the driving dynamics data of the towing vehicle and a kinematic model of the entire vehicle geometry. If the comparison between the measured and the ideal trailer behavior reveals a defined deviation, this is considered instability of the trailer.

[0007] From DE 10 2004 029 004 A1, a method for determining quantities describing the position of a trailer relative to a towing vehicle of a vehicle combination is known. In this method, driving condition data of the vehicle combination are recorded and monitored, and the quantities describing the position of the trailer relative to the towing vehicle are determined by an observation system based on the driving condition data and geometry data of the vehicle combination. If the fixed geometry of the vehicle is known, the angles between the towing vehicle and the trailer are calculated using a model for both forward and reverse travel. Measured quantities are then verified against these calculations.

[0008] To determine the trailer angle between a towing vehicle and a trailer, it is desirable if this can be done without additional sensors as much as possible and if it allows the current trailer angle to be determined in as many driving situations as possible.

[0009] The invention is therefore based on the objective of providing an improved method for estimating a trailer angle value.

[0010] According to the invention, this problem is solved in a method of the type mentioned at the outset by comprising the following steps: - Providing a model of the towing vehicle and the trailer coupled to the towing vehicle, wherein the model describes a dependence of at least one trailer angle on one or more driving parameters of the towing vehicle, - Initializing at least one first instance of the model with at least one first trailer angle start value, which describes a maximum angle when the trailer turns in a first direction, and a second instance of the model with at least one second trailer angle start value, which describes a maximum angle when the trailer turns in a second direction, for which at least one trailer angle is determined before the start of a movement of the towing vehicle. - Continuous reception of one or more driving parameters of the towing vehicle during movement of the towing vehicle, - Continuous calculation of at least one first hypothesis for the at least one trailer angle with the first instance of the model and of a second hypothesis for the at least one trailer angle with the second instance of the model, wherein the hypotheses are calculated based on one or more driving parameters, - Continuous estimation of the pendant angle value depending on at least the first hypothesis and the second hypothesis for at least one pendant angle.

[0011] The method according to the invention is a computer-implemented method that can be carried out, for example, in a vehicle's computer or control unit. The method according to the invention serves to determine an estimated value for a trailer angle, i.e., an angle lying in a plane parallel to the road surface that describes a rotation of the trailer about an axis extending in the vertical direction of the vehicle. The trailer angle can also be referred to as the articulation angle.

[0012] In a vehicle combination, the entire angle between the trailer and the towing vehicle can be described by a single trailer angle, for example, in the case of a trailer with a rigid drawbar or one connected to the towing vehicle as a semi-trailer. It is also possible for the entire angle between a trailer and the towing vehicle to be described by several trailer angles as defined by the invention, for example, by two trailer angles in the case of a trailer with a drawbar rotatably mounted on the trailer. In this case, a first trailer angle occurs between the towing vehicle and the drawbar, and a second trailer angle occurs between the drawbar and the rest of the trailer body. Using this method, estimated values ​​for the individual trailer angles can also be determined for vehicle combinations where more than two trailer angles occur, for example, in the case of towing vehicles pulling more than one trailer, as described in more detail below.

[0013] In the first step of the process, a model of the vehicle combination, consisting of the towing vehicle and the trailer, is provided. This model can, for example, be stored in a control unit of the towing vehicle specifically designed for this process, or it can be transmitted to such a control unit. The model is adapted to the specific towing vehicle and trailer, with the model parameters being stored in the control unit and / or entered by a user via a user interface, for example, when changing trailers or using the trailer for the first time. Starting from an initial value for at least one trailer angle, the model can determine the temporal development or progression of this angle for continuously recorded driving parameters. A kinematic single-track model can be used, for example. However, other models can also be used, e.g.,...Dynamic single-track models, an Ackermann model, or other models that can describe a relationship between the trailer angle and one or more driving parameters.

[0014] In the next step of the process, multiple instances of the model are created or initialized. For a vehicle combination with a single trailer angle, a first instance of the model is created with a first trailer angle start value, which describes the maximum angle when the trailer is turned in a first direction, and a second instance of the model is created with at least a second trailer angle start value, which describes the maximum angle when the trailer is turned in a second direction. For a vehicle combination with more than one trailer angle, more than two instances of the model are initialized, as described in more detail below.

[0015] The model instances are initialized, in particular, before the towing vehicle begins to move. The first trailer angle start value describes a maximum angle when the trailer turns in a first direction, for example, to the left, whereas the second trailer angle start value describes a maximum angle when the trailer turns in a second direction, which is opposite to the first direction, for example, to the right. It is possible, but not required, for the magnitude of the first and second trailer angle start values ​​to be the same relative to a zero angle, or when the trailer is oriented parallel to or in line with the towing vehicle.

[0016] During the movement of the vehicle combination, one or more driving parameters of the towing vehicle are continuously determined. These driving parameters can be, in particular, parameters describing the movement of the towing vehicle. Based on these driving parameters, at least two hypotheses for the trailer angle are continuously calculated. Each hypothesis is based on a different instance of the model and thus on a different initial trailer angle value. Therefore, the different initial trailer angle values ​​are continuously recalculated using the model and the driving parameters. Starting from these different initial assumptions, the system determines what value the trailer angle would currently assume, depending on the movement of the towing vehicle that has already occurred.

[0017] The current trailer angle value is then estimated from at least two hypotheses. The inventive method utilizes the fact that, after a certain forward driving distance or a certain number of forward driving maneuvers, the hypotheses converge towards the actual trailer angle value despite the different initial trailer angle values. In this way, the actual trailer angle can advantageously be estimated without needing to know the actual angle at the beginning of the estimation or without having to set a specific angle, for example, 0° when the trailer and towing vehicle are parallel.

[0018] According to the invention, the estimated trailer angle value is subsequently made available to provide a driver assistance function of the towing vehicle. This driver assistance function could, for example, be an articulation angle warning that alerts the driver when the trailer angle becomes too large. Additionally or alternatively, the driver assistance function could also be an assistance function enabling autonomous or at least semi-autonomous driving of the towing vehicle, which uses the at least one trailer angle for planning driving trajectories and / or for controlling or regulating vehicle movement along such a trajectory. Providing the trailer angle to other driver assistance functions is also possible.

[0019] Advantageously, the inventive method allows one or more current trailer angle values ​​to be determined for a vehicle combination consisting of a towing vehicle and a trailer without the use of additional sensors. It is also advantageous to use a trailer angle value determined by the inventive method to compare or validate a trailer angle value determined by other means. The inventive method can be easily implemented, for example, in an existing vehicle control unit.

[0020] In a preferred embodiment of the invention, the trailer angle value can be continuously estimated as an average of the currently considered hypotheses. As the individual hypotheses converge towards the actual trailer angle value, the estimation of the trailer angle value becomes increasingly accurate. The average value can, for example, be an arithmetic mean of the two or more hypotheses relating to the respective trailer angle.

[0021] According to the invention, an uncertainty measure for the estimated trailer angle value can be continuously determined as a function of a difference, in particular a difference and / or a deviation, between the hypotheses, wherein the trailer angle value is used to provide at least one driver assistance function when the uncertainty measure falls below a predetermined limit. For example, the uncertainty measure can be the difference between two hypotheses. For a trailer angle value determined from more than two hypotheses, for example, a standard deviation of the multiple hypotheses can be used as the uncertainty measure.

[0022] The uncertainty measure allows situations in which the hypotheses have not yet converged sufficiently to be identified. Accordingly, the trailer angle value determined by the method can only be considered sufficiently accurate and used for a driver assistance function that operates depending on the trailer angle if it falls below a predefined limit determined by the uncertainty measure.

[0023] According to the invention, if the predetermined limit value or a further limit value is undershot by the uncertainty measure, only one of the hypotheses can continue to be calculated. From the point at which the hypotheses have sufficiently converged, it is sufficient to continue calculating only one of the hypotheses, since they now yield sufficiently similar results despite the different initial values ​​of the trailer angle. From this point on, the trailer angle value can then be considered identical to the single hypothesis that continues to be calculated.

[0024] In a preferred embodiment of the invention, it can be provided that when the towing vehicle changes direction from forward to reverse, the model instances are reinitialized, with the calculation of the hypotheses and the estimation of the trailer angle value continuing when forward travel resumes, and / or that the calculation of the hypotheses is suspended while the towing vehicle is stationary. During reverse travel, if the hypotheses have not yet converged sufficiently, they may diverge, thereby increasing an uncertainty measure or making the estimate of the trailer angle value increasingly inaccurate. It is also possible that the hypotheses behave approximately the same during reverse travel, but the actual articulation angle develops in the opposite direction due to model inaccuracies.This can be addressed by interrupting the current trailer angle estimation when switching from forward to reverse travel. The trailer angle estimation can then be resumed by reinitializing the instances and restarting the estimation process after switching back to forward travel.

[0025] According to the invention, the model can be a kinematic single-track model of the towing vehicle and the trailer. A kinematic single-track model has the advantage of being a comparatively simple model to calculate, resulting in a comparatively low computational effort. Furthermore, the converging hypotheses for the trailer angle advantageously allow a sufficiently accurate trailer angle value to be determined using a kinematic single-track model. Alternatively, other types of models can be used that include a geometric description of the towing vehicle and the coupled trailer.

[0026] In a kinematic single-track model of the towing vehicle and the coupled trailer, it can be provided that the towing vehicle is described by an axle spacing between at least one rear axle of the towing vehicle and a front axle of the towing vehicle, and that the coupled trailer is described by a distance between a center of the at least one rear axle of the towing vehicle and a trailer joint at which the trailer is coupled to the towing vehicle, as well as by a distance between a center of at least one rear axle of the trailer and the trailer joint.

[0027] According to the invention, the driving parameters can include at least a longitudinal speed of the towing vehicle and a steering angle of the towing vehicle. Depending on the embodiment, further and / or other driving parameters of the towing vehicle and / or the trailer can also be used. The driving parameters can be measured, for example, by corresponding sensors of the towing vehicle, such as a speed sensor, a steering angle sensor, or the like, and / or by corresponding sensors of the trailer, and transmitted, for example, to a control unit designed to carry out the method according to the invention.

[0028] In a preferred embodiment of the invention, it can be provided that, for two or more trailer angles between the towing vehicle and the trailer, an instance is initialized for each possible combination of first and second trailer start values ​​for the trailer angles. For each instance, a hypothesis of the trailer angle is calculated for each of the trailer angles, and the trailer angle values ​​of the at least two trailer angles are estimated from the values ​​of all hypotheses for the respective trailer angle. The trailer start values ​​can, in particular, describe the maximum possible steering angle in each direction for each of the trailer angles. Since there are thus two trailer angle start values ​​for each trailer angle, the hypotheses, each containing one possible combination of the different trailer start angles, result in 2 for n trailer angles. nInstances of the model and therefore for each of the trailer angles also 2 n Hypotheses.

[0029] A control unit according to the invention is provided to be configured for carrying out a method according to the invention.

[0030] A vehicle according to the invention is provided to include a control unit according to the invention.

[0031] All advantages and embodiments described above in relation to the method according to the invention apply accordingly to the control unit according to the invention and to the vehicle according to the invention, and vice versa.

[0032] Further advantages and details of the invention will become apparent from the exemplary embodiments described below and from the drawings. These are schematic representations and show: Fig. 1 an embodiment of a vehicle according to the invention, Fig. 2 a flowchart of an embodiment of the method according to the invention, Fig. 3 a kinematic single-track model for a towing vehicle with a coupled trailer, Fig. 4 a schematic representation of two different trailer starting angles for a trailer angle, Fig. 5 the position of a towing vehicle and the coupled trailer for trailer angles according to a first and a second hypothesis, Fig. 6 a kinematic model for a towing vehicle with a coupled trailer, where two trailer angles are present, Fig. 7. Schematic representation of the possible combinations for the trailer starting angles for the model according to Fig. 6.

[0033] In Fig. Figure 1 shows an embodiment of a vehicle 1 according to the invention. The vehicle 1 comprises a control unit 2, which is configured to carry out a method for estimating at least one trailer angle between the vehicle 1 and a trailer 3 coupled to the vehicle 1. The control unit 2 can be, for example, a microcontroller, a processor, or another type of computer.

[0034] Furthermore, the vehicle 1 comprises at least one speed sensor 4, which can measure the current speed of the vehicle 1, and at least one steering angle sensor 5, which can determine the current steering angle 5 of the vehicle 1. The vehicle 1 coupled to the trailer 3 is hereinafter also referred to as the towing vehicle 1. The speed sensor 4 and the steering angle sensor 5 of the vehicle 1 can communicate with the control unit 2 via a communication link of the vehicle 1, for example, a point-to-point connection or a data bus such as a CAN bus, and continuously transmit measurement data describing the speed and steering angle, respectively, to the control unit 2.

[0035] In the Fig. In the embodiment shown in Figure 1, the vehicle 1 is designed as a semi-trailer truck, which is coupled to a trailer 3 designed as a semi-trailer via a corresponding coupling device 6. The trailer 3 is rotatable about the coupling device 6 so that, during travel by the towing vehicle 1, in particular during cornering maneuvers of the towing vehicle 1, it can assume different trailer angles φ relative to a longitudinal axis 7 of the combination formed by the towing vehicle 1 and the trailer 3.

[0036] In Fig. Figure 2 shows a flowchart of an embodiment of a method according to the invention. The method serves to estimate the value of at least one trailer angle between a towing vehicle and a trailer. The method can, for example, be implemented as a computer-implemented method and executed by a correspondingly configured control unit 2 of a vehicle 1. The method can be used in particular when the vehicle 1 is coupled to a trailer 3 and at least one driver assistance system is to be operated depending on the estimated trailer angle.

[0037] In a first step S1 of the procedure, a model of the towing vehicle 1 and the trailer 3 coupled to the towing vehicle 1 is provided, wherein the model describes the dependence of at least one trailer angle on one or more driving parameters of the towing vehicle. The model can, for example, be a kinematic single-track model of the towing vehicle and the trailer. Driving parameters, on which the model can calculate a current trailer angle value starting from an initial trailer angle value, can include, for example, the speed of the towing vehicle 1 and the steering angle of the towing vehicle 1, which can be measured, for example, by sensors 4 and 5 during a journey of the towing vehicle 1.

[0038] In Fig. Figure 3 is an example of a model 8 designed as a kinematic single-track model for the towing vehicle 1 and the trailer 3. The trailer angle φ describes the articulation angle of the trailer 3 relative to the towing vehicle 1. The geometric quantities used in model 8 are w b , I h and I t , where w b the axle spacing of the towing vehicle between a front axle center or the center of one of several front axles and a rear axle center or the center of one of several rear axles, I h the distance between the rear axle center and the coupling device 6 and I tDescribe the distance between the center of a rear axle or the center of several rear axles of the trailer 3 and the coupling device 6. The position of the coupling device 6 can be, in particular, the point through which the axis of rotation around which the trailer 3 can rotate passes, for example, the position of a kingpin, a ball head, or the like.

[0039] Further shown are in Fig. Figure 3 shows the driving parameters v, which denotes the longitudinal speed of the towing vehicle 1, and δ, which denotes the current steering angle of the towing vehicle 1. The temporal dynamics of the trailer angle φ can be represented in the kinematic single-track model used as Model 8 as φ˙=v(tan δwb−sin φ+cos φ⋅lhwb⋅tan δlt) be expressed.

[0040] In step S2 of the in Fig. In the procedure described in section 2, at least one first instance 9 of the model 8 is then initialized with at least one first trailer angle start value, which describes a maximum angle when the trailer 3 is turned in a first direction, and a second instance 10 of the model with at least one second trailer angle start value, which describes a maximum angle when the trailer is turned in a second direction.

[0041] The first trailer starting angle can be interpreted as a steering angle φ1, which corresponds, for example, to a maximum steering angle of trailer 3 to the left, and the second trailer starting angle as a steering angle φ2, which corresponds, for example, to a maximum steering angle of trailer 3 to the right. The two instances 9 and 10, each with their respective different trailer starting angles φ1 and φ2, are shown schematically in Fig. 4 shown.

[0042] Steps S1 and S2 of the in Fig. The procedures described in section 2 are executed in particular before the start of a journey, i.e., before the towing vehicle 1 begins to move forward. In step S3 of the procedure, which is executed in particular after the towing vehicle 1 and the trailer 3 have begun to move forward, current values ​​of one or more driving parameters of the towing vehicle 1 are continuously received during its movement. In this case, these are the current values ​​of the speed v and the steering angle δ of the towing vehicle 1, which are measured, for example, by the corresponding sensors 4, 5 and transmitted to the control unit 2.

[0043] Based on the current values ​​of the driving parameters v, δ, in step S4 of the procedure at least one first hypothesis 11 for the at least one trailer angle φ with the first instance 9 of the model 8 and a second hypothesis 12 for the at least one trailer angle φ starting from the second instance 10 of the model 8 are continuously calculated, wherein the hypotheses 11, 12 are calculated on the basis of the one or more driving parameters v, δ.

[0044] During continuous forward travel of the towing vehicle 1, hypotheses 11 and 12 converge, as described in Fig. Figure 5 shows that even with a travel distance of less than 100 m for the towing vehicle 1, the actual value of the trailer angle φ is already different. Hypotheses 11 and 12 are illustrated as trajectories 16 and 17 of the trailer 3. The trailer angle calculated by each hypothesis 11 and 12 results from the respective position of the trailer 3 on the respective trailer trajectory 16 and 17 relative to the corresponding position of the towing vehicle 1 as it moves along a towing vehicle trajectory 18.

[0045] In step S5 of the procedure, the trailer angle value is continuously estimated as a function of at least the first hypothesis 11 and the second hypothesis 12 for at least one trailer angle φ. The estimation is based on the values ​​for the trailer angle φ continuously determined using hypotheses 11 and 12. In particular, the trailer angle value can be continuously estimated as an average of the currently relevant hypotheses 11 and 12.

[0046] Subsequently, in step S6 of the procedure, the trailer angle value can be provided to a driver assistance system of the towing vehicle 1 and / or the trailer 3. For this purpose, an uncertainty measure for the estimated trailer angle value can be continuously determined as a function of the difference between hypotheses 11 and 12, or between the currently determined values ​​for the trailer angle using hypotheses 11 and 12. The trailer angle value can only be used to provide at least one driver assistance function if the uncertainty measure falls below a predefined limit. For example, a difference between hypotheses 11 and 12 and / or a standard deviation between several hypotheses 11 and 12 can be used as the uncertainty measure.

[0047] If the uncertainty measure falls below the limit value, or alternatively below a different, further limit value, only one of hypotheses 11 and 12 can continue to be calculated. This can advantageously reduce the computational effort in the control unit 2 of vehicle 1. Furthermore, to reduce the computational effort, it can be provided that the calculation of hypotheses 11 and 12 is suspended while the towing vehicle 1 is stationary.

[0048] The driver assistance system could, for example, be a jackknife warning system that alerts the driver to excessive jackknifing angles by issuing a warning signal. Additionally or alternatively, it could also be a driving function that controls the longitudinal and / or lateral guidance of the towing vehicle 1, at least semi-autonomously. It is possible that the estimated trailer angle value is used to compare an angle measurement taken by one or more sensors on the towing vehicle 1 and / or the trailer 3, for example, to monitor for sensor failure and / or to verify the plausibility of received angle measurements.

[0049] When the towing vehicle 1 changes direction from forward to reverse, the instances of model 8 can be reinitialized. The calculation of hypotheses 11 and 12 and the estimation of the trailer angle value are only resumed when forward travel is restarted. This accounts for the fact that hypotheses 11 and 12 increase during reverse travel if they have not yet converged sufficiently, for example, if the uncertainty measure has not yet fallen below the limit. If hypotheses 11 and 12 have converged, or if only one of them is still being calculated, the current trailer angle value can still be estimated during reverse travel, as described above.

[0050] In Fig. Figure 6 shows another model 13. Model 13 is also a kinematic single-track model of a towing vehicle 1 and a trailer 14, where the trailer 14 is a turntable trailer and has a rotating drawbar 15. For clarity, the actual outlines of the towing vehicle 1 and the trailer 14 are shown as dashed lines in relation to the respective components of the kinematic single-track model.

[0051] The trailer 14 is rotatably coupled to a trailer coupling 19 of the towing vehicle 1 via the rotatable drawbar 15, so that two trailer angles φ are formed. a , φ b result. Here, φ describes a the angle between the towing vehicle 1 and the drawbar 15 and φ b the angle between the drawbar 15 and a main part 20 of the trailer 3.

[0052] In the kinematic single-track model used as model 13, the trailer angle φ acan be determined analogously to formula (1). Also φ b can be estimated using formula (1), however, a modified steering angle δ' = φ1 + β is used instead of the steering angle δ, where β describes a sideslip angle of the trailer coupling 16. Furthermore, the geometric parameters of formula (1) must also be adjusted according to the dimensions of the drawbar 15 and the trailer 14.

[0053] With two or more trailer angles φ a , φ b In the procedure for estimating the trailer angle values, between the towing vehicle 1 and the trailer 14, an instance is used for each possible combination of first and second trailer starting values ​​for the respective trailer angles φ. a , φ b initialized, with each instance having a hypothesis of the pendant angle for each of the pendant angles φ a , φ bis calculated and the pendant angle values ​​of at least two pendant angles are each derived from the values ​​of all hypotheses for the respective pendant angle φ. a , φ b to be estimated. The instances and starting angles of support resulting in this way for the formation of the hypotheses are for the in Fig. Model 13 shown schematically in 6 Fig. 7 shown.

[0054] For estimating the pendant angles φ a , φ b and for calculating the respective uncertainty measure for the trailer angles φ a , φ b A total of four hypotheses are used, which are initialized as follows: {[φa,1,φb,1],[φa1,φb,2],[φa,2,φb,1],[φa,2,φb,2]}.

[0055] The angle between the towing vehicle 1 and the drawbar 15 is calculated from the mean of the four hypotheses for φ. a , i.e., the respective values ​​for φ acalculated from the four hypotheses. For the calculation of the uncertainty measure φ a For example, the standard deviation from the four hypotheses for φ will be calculated. a calculated. The angle φ b between the drawbar 15 and the main part 20 of the trailer 3, the mean of the four hypotheses for φ is calculated analogously. b calculated. For the calculation of the uncertainty measure, for example the standard deviation from the four hypotheses for φ is used. b determined.

[0056] The procedure described above can be generalized to models with n trailer angles. For vehicle combinations or models with n trailer angles, the different possible combinations of the respective starting values ​​for the n angles are considered analogously. Accordingly, 2 n Combination options are obtained from different trailer starting angles, which are accordingly referred to as 2 nInstances of the corresponding model are initialized and used to calculate 2 n Hypotheses serve as a basis. The individual pendant angles can then be determined from the two values ​​in each case. n Hypotheses, i.e., the values ​​calculated in the hypotheses for the respective angle, are determined.

Claims

[1] Computer-implemented method for estimating a trailer angle value for at least one trailer angle (φ) between a trailer (3, 14) and a towing vehicle (1) coupled to the trailer (3, 14), comprising the steps: - Providing a model (8, 13) of the towing vehicle (1) and the trailer (8, 13) coupled to the towing vehicle (1), wherein the model (8, 13) describes a dependence of the at least one trailer angle (φ) on one or more driving parameters of the towing vehicle (1), - Initializing at least one first instance (9) of the model (8, 13) with at least one first trailer angle start value, which describes a maximum angle when the trailer (3, 14) hits in a first direction, and a second instance (10) of the model (8, 13) with at least one second trailer angle start value, which describes a maximum angle when the trailer (3, 14) hits in a second direction, for which at least one trailer angle (cp) - Continuous reception of one or more driving parameters of the towing vehicle (1) during a movement of the towing vehicle (1), - Continuous calculation of at least one first hypothesis (11) for the at least one trailer angle (φ) with the first instance (9) of the model (8, 13) and of a second hypothesis (12) for the at least one trailer angle (φ) with the second instance (10) of the model (8, 13), wherein the hypotheses (11, 12) are calculated on the basis of one or more driving parameters, - Continuous estimation of the pendant angle value depending on at least the first hypothesis (9) and the second hypothesis (10) for at least one pendant angle (cp), - Providing the trailer angle value to a driver assistance system of the towing vehicle (1) and / or the trailer (3, 14). [2] Method according to claim 1, characterized by , that the pendant angle value is continuously estimated as a mean value of the currently current hypotheses (11, 12). [3] Method according to claim 1 or 2, characterized by, that a measure of uncertainty of the estimate of the trailer angle value is continuously determined as a function of a difference, in particular a difference and / or a deviation, between the hypotheses (11, 12), wherein the trailer angle value is used to provide at least one driver assistance function if the measure of uncertainty falls below a predetermined limit. [4] Method according to claim 3, characterized by , that if the specified limit value or a further limit value is undershot by the uncertainty measure, only one of the hypotheses (11, 12) will continue to be calculated. [5] Method according to any of the preceding claims, characterized by, that when the direction of travel of the towing vehicle (1) changes from forward travel to reverse travel, the instances (9, 10) of the model (8, 13) are reinitialized, and the calculation of the hypotheses (11, 12) and the estimation of the trailer angle value are continued when forward travel is resumed. [6] Method according to any of the preceding claims, characterized by , that the model (8, 13) is a kinematic single-track model of the towing vehicle (1) and the trailer (3). [7] Method according to any of the preceding claims, characterized by , that the driving parameters include at least a longitudinal speed (v) of the towing vehicle (1) and a steering angle (δ) of the towing vehicle (1). [8] Method according to any of the preceding claims, characterized by, that if there are two or more trailer angles (φ) between the towing vehicle (1) and the trailer (3), an instance (9, 10) is initialized for each possible combination of first and second trailer start values ​​for the trailer angles (φ), wherein for each of the instances (9, 10) a hypothesis (11, 12) of the trailer angle (φ) is calculated for each of the trailer angles (φ) and the trailer angle values ​​of the at least two trailer angles (φ) are estimated from the values ​​of all hypotheses (11, 12) for the respective trailer angle (φ). [9] Control unit configured to carry out a method according to any of the preceding claims. [10] Vehicle comprising a control unit (2) according to claim 9.

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