Assistance system and computer program to support the coupling of a trailer

Abstract

The assistance system (12) and the computer program serve to support a coupling process for attaching a trailer (6) to a trailer coupling (4) of a vehicle (2). The assistance system (12) has a control unit (14) which, within a coupling mode (K), causes a stop signal (H) to be issued when a coupling position (KP) is reached, such that the vehicle (2) is held at the coupling position (KP) by an active braking force until the trailer (6) is coupled, the active braking force being applied either or in combination by a hydraulic service brake (18) or by a drive motor (16) of the vehicle (2).

Description

[0001] The invention relates to an assistance system and a computer program for supporting a coupling process for coupling a trailer to a trailer hitch of a vehicle.

[0002] From DE 10 2017 220 459 A1 an assistance system can be seen in which a coupling process is supported by means of a camera system, with the help of which a locking position between a trailer-side coupling part and a vehicle-side ball head is determined.

[0003] DE 10 2019 213 223 A1 concerns an assistance system for collision avoidance in which the vehicle is autonomously guided towards a trailer drawbar and the vehicle is automatically braked when the trailer drawbar is detected at a predetermined distance to the trailer coupling of the vehicle by means of an analysis of image data.

[0004] DE 10 2014 003 953 A1 describes a camera-based assistance system that supports coupling or automatically makes steering interventions.

[0005] The actual coupling process is usually carried out manually. If the driver does this himself, he has to get out of the vehicle. One problem with this is ensuring that the vehicle remains exactly in the desired position, especially on a slope.

[0006] Based on this, the invention aims to provide an improved assistance system that supports coupling, in particular coupling on a slope.

[0007] The problem is solved according to the invention by an assistance system for supporting the coupling process of attaching a trailer to a vehicle's trailer hitch. The assistance system includes a control unit configured such that a stop signal is issued upon reaching a coupling position, and the vehicle is held in the coupling position by an active braking force until the trailer is coupled. This braking force is applied either by a hydraulic service brake or, in particular, by an electric drive motor of the vehicle, either selectively or in combination. The term "drive motor of the vehicle" refers to the drive motor for propelling the vehicle during normal operation.

[0008] The coupling position generally refers to the position in which the two coupling partners, i.e., the vehicle-side coupling part and the trailer-side coupling part, are in the relative position required for mechanical coupling. Typically, the trailer-side coupling part is located above the vehicle-side coupling part.

[0009] The coupling process refers to the process of moving the vehicle towards the coupling position and mechanically coupling the trailer to the trailer hitch.

[0010] A suitable vehicle is therefore equipped with such an assistance system. This vehicle is, in particular, a (non-rail-bound) road vehicle, and especially a passenger car. Preferably, it is a (fully) electrically powered vehicle, which therefore has an electric drive motor.

[0011] As explained at the beginning, the actual coupling process ultimately requires manually connecting the two coupling components, i.e., mechanically connecting the trailer hitch on the vehicle to the coupling device on the trailer. This is typically done by lowering the trailer coupling device so that the ball head of the vehicle's trailer hitch engages. If this is done by the driver of the vehicle, they must exit the vehicle.

[0012] In modern cars, when the driver exits the vehicle, the system automatically switches to park mode and activates a parking brake system, typically a parking brake or parking lock. Recent developments, particularly legislative ones, indicate that in such cases, activating only a parking lock is sufficient. This means that in the future, a parking lock will be enough, and an additional, for example, electric parking brake will no longer be necessary.

[0013] A parking lock is generally understood to be a device for blocking the drivetrain. Specifically, this is usually achieved by mechanically blocking a gearbox within the drivetrain. For example, a claw engages with the gearbox for this purpose.

[0014] The term "parking brake" generally refers to a locking brake, a locking system in which a brake pad is pressed against a brake disc, either mechanically or electrically. Typically, the parking brake only acts on the rear wheels.

[0015] Particularly when using a parking lock, there is a risk that the vehicle, especially when positioned on a slope, will still travel a small distance (rolling distance) before the parking lock engages. This rolling distance can be up to 15 cm, for example. Because of this rolling distance, the previously engaged coupling position is not maintained, making manual coupling difficult.

[0016] The proposed measure, whereby the assistance system issues a specific stop signal during a coupling process, thereby activating or keeping the hydraulic service brake activated and / or fixing the vehicle's position (especially its electric drive motor), ensures that the vehicle remains in its current position, thus facilitating easy manual coupling. This is particularly relevant for vehicles equipped only with a parking lock and not a parking brake.

[0017] In the event of a clutch engagement, the assistance system secures the vehicle in the engaged position using the hydraulic brake and / or the electric drive motor, regardless of manual input from the driver, and especially when the driver is not (or no longer) operating the brake pedal and / or the accelerator pedal.

[0018] In the case of fixation by the electric drive motor, it is controlled and energized in a suitable manner so that it exerts, for example, a driving force that counteracts the downward force of gravity and thus holds the position. The electric drive motor is therefore energized in such a way that it is held in a defined rotational position.

[0019] The hydraulic service brake is the actual service braking system used during normal driving. The braking force is transmitted hydraulically to corresponding brake cylinders, which press a brake pad against a brake disc.

[0020] The assistance system detects the clutch engagement process, for example, automatically or through manual activation by the driver, and switches to a clutch mode. In a preferred configuration, a conventional automatic parking mode is temporarily deactivated in such a clutch mode, whereby such an automatic parking mode automatically activates the parking brake system in the event of a parking situation. A parking situation exists, for example, when the driver manually activates the parking brake system, and / or when they switch off the engine, and / or when they leave the vehicle, etc.

[0021] As an alternative to temporarily deactivating the automatic parking mode, it is not deactivated, meaning that the parking brake system remains activated alongside the active braking force. In this case, the parking brake system is also activated during the manual clutch operation. However, if the parking lock is engaged, it is often engaged but not yet in the mechanical engagement phase where no relative movement is possible (i.e., after the parking lock is engaged, some rolling is still possible until the vehicle is engaged to apply the holding force).

[0022] In a preferred embodiment, the control unit is configured to deactivate the active braking force and transfer it to the parking brake system after the coupling has been successfully engaged, i.e., when the two coupling parts are mechanically connected. If the parking brake system was not already activated, it is then activated. If the parking brake system was previously activated, it now assumes the holding function. During this transfer to the parking brake system, the slight rolling of the vehicle described earlier may occur.

[0023] Deactivating the active braking force, in the case of a hydraulic service brake, means releasing the hydraulic brake so that the brake shoes are no longer hydraulically pressed against the respective brake disc. In the case of a drive motor, deactivating the active braking force means switching off the drive motor, so that it is no longer receiving power.

[0024] Preferably, the control unit is configured such that the active braking force is only deactivated after a release signal indicating that no person is in the danger zone between the vehicle and the trailer. This measure ensures that no one is injured when switching to the parking brake system and any resulting slight rolling of the vehicle.

[0025] The release signal can either be activated manually or, preferably, is issued automatically by the assistance system. A combination is also possible, allowing the release signal to be activated both manually and automatically. In the preferred configuration for automatic activation, a sensor system checks whether a person or object is located in the danger zone between the vehicle and the trailer.

[0026] In a preferred embodiment, it is identified, either manually or automatically, whether the manual coupling process has been successfully completed. Following this, the aforementioned switchover and transfer to the parking brake system is carried out, particularly after verifying that the release signal is present.

[0027] Automatic identification is preferably carried out using a sensor system, such as a camera-based system. Alternatively or additionally, it is checked, for example, whether a required electrical connection exists between the vehicle and trailer, etc.

[0028] In a preferred further development, the control unit is also configured to assist the driver by providing driving instructions when reaching the coupling position and / or to autonomously steer the vehicle into the coupling position. This is achieved in particular by means of a sensor system, especially a camera system, which detects the position of the trailer and specifically the trailer-side coupling component. Depending on the detected position, a trajectory is then preferably calculated along which the vehicle-side coupling component can be guided towards the trailer-side coupling component. The instructions to the driver or the autonomous steering are then based on this determined trajectory, which can also be adjusted if necessary. For this purpose, at least one and preferably several of the following steps are initiated: - Visual and / or acoustic signals are generated to provide the driver with guidance on reaching the desired clutch position. This works, for example, in the same way as a parking assistant, where the driver is given visual and / or acoustic driving instructions. - Steering torque recommendations are generated and communicated to the driver, for example by generating steering impulses perceptible via the steering wheel, similar to lane keeping assistants. - In the case of autonomous steering, the assistance system automatically performs the necessary movements of the vehicle for longitudinal and lateral guidance.

[0029] In a preferred further development, the control unit is configured to automatically detect whether the coupling process has been initiated. This is achieved by performing several of the following steps. Specifically, a camera system and the evaluation of captured image data are used for the automatic detection of the coupling process. - It is checked whether a trailer hitch is extended or fitted. This is essentially a basic requirement that is absolutely essential. - It is checked whether reverse gear is engaged. This is also a basic requirement that is preferably checked without fail. Data from a sensor system, specifically a rear-view camera, is evaluated to detect the presence of a trailer. Specifically, the presence of a drawbar is recorded. This rear-view camera also provides the previously described information needed to determine a suitable trajectory for coupling.

[0030] When a coupling process is detected, a request is preferably still transmitted to the driver via a suitable communication interface as to whether he would like assistance and / or whether he would like autonomous guidance of the vehicle to the coupling position.

[0031] After the coupling process has been identified, the coupling mode is automatically activated.

[0032] As an alternative to automatic detection of the clutch process, the clutch mode can also be activated manually by the driver.

[0033] According to the invention, the problem is further solved by a computer program comprising commands which, when executed by a control unit of a vehicle, cause a stop signal to be issued upon reaching a coupling position, such that the vehicle is held at the coupling position by an active braking force until the trailer is coupled, wherein the active braking force is exerted by a hydraulic service brake and / or by a drive motor, in particular an electric one.

[0034] The advantages and preferred configurations previously mentioned with regard to the assistance system can also be applied analogously to the computer program. That is, the previously mentioned preferred further steps, for the execution of which the control unit is designed, are also implemented in preferred further developments in the computer program, so that they are also initiated by the control unit when the computer program is executed.

[0035] An embodiment of the invention is explained in more detail below with reference to the figures. These show highly simplified representations: Fig. 1. Supervision of a vehicle and a trailer as well as Fig. 2. A flowchart to explain the individual steps taken to support a coupling process.

[0036] In Fig. Figure 1 is a schematic representation of a vehicle 2 with a trailer coupling 4, which has a ball head as the vehicle-side coupling component. Also shown schematically is a trailer 6 with a drawbar 8, which has a trailer-side coupling component 10 at its front end, commonly referred to as a tow ball.

[0037] The vehicle 2 is equipped with a (driver) assistance system 12, which has control instructions in the form of a computer program C, which is implemented in a control unit 14.

[0038] The assistance system 12 is designed to perform a coupling mode K and, in this coupling mode K, assists the driver in coupling the trailer 6. In doing so, the assistance system 12 accesses some hardware components of the vehicle 2.

[0039] Vehicle 2 has, in particular, a drive system that provides propulsion for the vehicle 2. The drive system includes, in particular, an electric drive motor 16 (traction motor). Furthermore, vehicle 2 has a hydraulic service brake 18 and a parking brake system 20. The parking brake system 20 preferably has only a parking lock (and not a parking brake), in which a mechanical lock can engage with a transmission in the drive train, which is not shown in detail here.

[0040] Vehicle 2 is further equipped with a rear-facing sensor system 22, which in particular includes a rear camera.

[0041] A procedure performed by the assistance system 12 to support the driver and a coupling process to couple the trailer 6 to the trailer coupling 4 is shown in the flowchart according to Fig. 2 explained in more detail. Each step is initiated by control unit 14.

[0042] In a first step (a), it is checked whether a clutch operation is taking place and has been initiated or is about to be initiated. This check, and if necessary, the determination of whether a clutch operation is taking place, is carried out manually, for example, based on user input. The driver can, for instance, actively activate clutch mode K.

[0043] Alternatively, the assistance system 12 automatically detects that a coupling process has been initiated or is imminent. For this purpose, it checks, for example, whether a trailer hitch 4 is present, whether it is extended, and whether reverse gear is engaged. Furthermore, the sensor system 22, and specifically the rear-view camera, checks and evaluates whether a trailer 6 is nearby or whether the vehicle 2 is approaching the trailer 6. The reference point for this evaluation is, in particular, the drawbar 6 with the trailer-side coupling part 10, which serves as a characteristic feature.

[0044] If such a clutch operation is detected, clutch mode K is activated in step b). In this process, for example, an automatic parking mode P is temporarily deactivated during the clutch operation. Automatic parking mode P typically ensures that the parking brake system 20 is activated when the vehicle is parked. Such activation is usually intended to occur when, for example, the driver leaves the vehicle, i.e., when the door is opened. However, deactivating automatic parking mode P is not strictly necessary.

[0045] After activating clutch mode K, for example, in step c) the driver is asked whether and, if so, how they would like support during the clutching process. This includes, for example, assistance with driving instructions or even fully autonomous approach of vehicle 2 to a clutch position KP (see...). Fig. 1) offered.

[0046] In step d), the coupling position is subsequently approached either assisted or autonomously. The coupling position KP is regularly defined by the position of the trailer-side coupling part 10. The vehicle-side coupling part of the trailer coupling 4, i.e., the ball head, must be moved into this coupling position KP and below the trailer-side coupling part 10.

[0047] During assisted approach, the assistance system provides the driver with 12 driving instructions, optionally as visual or audible signals, or steering input recommendations. Furthermore, the vehicle can, for example, perform some driving and / or steering maneuvers, or the vehicle can move completely autonomously into the coupling position.

[0048] In both assisted and autonomous approach to the coupling position, the assistance system 12 preferentially determines a suitable trajectory T (see below). Fig. 1), along which the vehicle 2 shall proceed to reach the coupling position KP.

[0049] As soon as the coupling position KP is reached in step d), a stop signal H is generated and transmitted, thereby activating an active braking force and, in particular, the hydraulic service brake 18. Alternatively or additionally, the driving system, i.e., in particular the electric drive motor 16, can also be appropriately controlled so that the vehicle 2 is reliably held at the coupling position KP.

[0050] Activating the active braking force ensures that the vehicle 2 remains in the designated clutch position KP. The driver can then easily engage the clutch manually, connecting the two clutch components. It is worth noting that the active braking force is maintained specifically via the hydraulic service brake 18, even after the driver exits the vehicle.

[0051] After a successful coupling process, the successful coupling of the trailer 6 is verified and confirmed manually in optional step e), for example, by user input. Alternatively, the successful coupling is automatically detected by the assistance system 12. For this purpose, the aforementioned sensor system 22 and / or other sensors are used to determine whether the coupling was successful.

[0052] In step f), it is then checked whether there is still an object or person in a danger zone between vehicle 2 and trailer 6. If this is not the case, a release signal F is issued.

[0053] The release signal F is either manually issued by the driver via a corresponding user input or automatically by the assistance system 12. For the automatic variant, the sensor system 22, in particular the rear camera, is preferably used to check whether objects / persons are in the danger zone.

[0054] If a release signal F is present, the active braking force is then deactivated in step g) in particular by issuing a switching signal U, i.e. for example the hydraulic service brake 18 is released and / or the driving system is deactivated and for this purpose in particular the drive motor 16 is switched off.

[0055] Simultaneously, power is transferred to the parking brake system 20, so that the vehicle 2 is held by the parking brake system 22. If the automatic parking mode P and thus the parking brake system 20 were deactivated in step b), then the parking brake system 20 and the automatic parking mode P are reactivated in step g). If the automatic parking mode was not deactivated in step b), then the parking brake system 20, and specifically, for example, a parking lock, is already in a locked state, but there is no frictional connection for transmitting the braking force. The frictional connection is only established after the active braking force is deactivated, whereby a slight rolling motion of the vehicle 2 is permitted.

[0056] In the final step h, the coupling mode K is finally terminated. REFERENCE MARK LIST: 2 vehicles 4 Towbar 6 trailers 8 Drawbar 10 trailer-side coupling part 12 Assistance systems 14 Control unit 16 Drive motor 18 hydraulic service brakes 20 Parking brake system 22 Sensor system C computer program K Clutch mode P Parking mode KP Dome Position T trajectory H Stop signal F Release signal U Switching signal QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 220 459 A1

[0002] DE 10 2019 213 223 A1

[0003] DE 10 2014 003 953 A1

[0004]

Claims

Assistance system (12) for supporting a coupling process for coupling a trailer (6) to a trailer coupling (4) of a vehicle (2), comprising a control unit (14) which, within the framework of a coupling mode (K), causes a stop signal (H) to be issued when a coupling position (KP) is reached, such that the vehicle (2) is held at the coupling position (KP) by an active braking force until the coupling of the trailer (6) has taken place, wherein the active braking force is applied optionally or in combination by a hydraulic service brake (18) or by a drive motor (16) of the vehicle (2). Assistance system (12) according to the preceding claim, wherein the control unit (14) is configured such that a parking brake system (20) is additionally activated when the coupling position (KP) is reached, or wherein an automatic parking mode (P) is temporarily deactivated during the coupling process, wherein the automatic parking mode (P) automatically activates a parking brake system (20) when a parking situation exists. Assistance system (12) according to one of the preceding claims, wherein the control unit (14) is configured to deactivate the active braking force after coupling has taken place and to transfer it to a parking brake system (20), or to activate it. Assistance system (12) according to the preceding claim, wherein the control unit (14) is configured such that the active braking force is only deactivated after a release signal (F) indicating that there is no person or object between the vehicle (2) and the trailer (6). Assistance system (12) according to the preceding claim, wherein the release signal (F) is automatically generated if a sensor system (22) detects that no person or object is in the danger zone. Assistance system (12) according to one of the preceding claims, in which it is identified by manual input or automatically when the coupling of the trailer (6) has been successfully completed. Assistance system (12) according to one of the preceding claims, wherein the control unit (14) is configured to assist a driver by providing driving instructions to reach the clutch position (CP) or to autonomously control the vehicle (2) into the clutch position (CP), wherein the following steps are particularly initiated: - Generating optical and / or acoustic signals, - Generating steering torque recommendations, - Executing longitudinal and lateral control of the vehicle (2). Assistance system (12) according to one of the preceding claims, wherein the control unit (14) is configured to automatically detect the coupling process and activate the coupling mode (K), preferably by performing several of the following steps: - It is checked whether a trailer coupling (4) is extended or present; - It is checked whether reverse gear is engaged; - Data from a sensor system, in particular a rear camera, are evaluated with regard to the presence of a trailer (6). Computer program comprising commands which, when executed by a control unit (14) of a vehicle (2), cause a stop signal (H) to be issued upon reaching a coupling position (KP), such that the vehicle (2) is held at the coupling position by an active braking force until the trailer (6) is coupled, wherein the active braking force is applied optionally or in combination by a hydraulic service brake (18) or by a drive motor (16) of the vehicle (2).

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