Uncoupling a trailer from a tractor

Abstract

A method (400) for assisting an operation of uncoupling a tractor (105) from a trailer (110), wherein the trailer (100) comprises a left and a right supporting leg (340), which can be extended independently of one another; comprises steps of determining (415) a first load of the trailer (110), which acts on the left supporting leg (340); of determining (415) a second load of the trailer (110), which acts on the right supporting leg (340); of individually extending (425, 430) a supporting leg (340), the specific load of which is below an assigned predetermined threshold value (240); and of enabling (455) the opening of a coupling (335) of the tractor (105) to the trailer (110) if a load of the trailer (110) acting on the tractor (105) is less than a predetermined further threshold value (240).

Description

[0001] Uncoupling a semi-trailer from a tractor

[0002] The present invention relates to a commercial vehicle comprising a tractor with a semi-trailer. In particular, the present invention relates to the uncoupling of the semi-trailer from the tractor.

[0003] A commercial trailer for road transport, which has at least one axle with wheels at a rear end, is adapted at its front end to rest on and be towed by a tractor.

[0004] Such a trailer is also known as a semi-trailer, semi-trailer, or semi-trailer. The tractor unit can also be called a tractor unit. To separate the semi-trailer from the tractor unit, support legs at the front of the trailer can be extended downwards to take its weight. The towing connection to the tractor unit can then be disconnected, and the tractor unit can be removed.

[0005] To improve the utilization of the tractor unit, it is desirable to automate the uncoupling process between the tractor unit and the trailer. This can be problematic if the ground is uneven, causing the tractor unit and / or trailer to lean sideways on the ground. This can interfere with the disconnection of the tractor unit and the trailer.

[0006] WO 2022 / 077063 A1 relates to a technology for loading or unloading a vehicle trailer with loading ramps attached to the rear of the vehicle. To enable another vehicle to safely drive over the loading ramps even on sloping ground, it is proposed to control the lengths of the loading ramps as well as the pitch and roll angles of the vehicle trailer.

[0007] One object of the present invention is to provide an improved technique for uncoupling a semitrailer from a tractor. The invention achieves this object by means of the subject matter of the independent claims. Subclaims specify preferred embodiments.According to a first aspect of the present invention, a method for assisting a decoupling operation of a tractor from a semi-trailer, the semi-trailer comprising a left and a right support leg that can be extended independently of each other, comprises steps of determining a first load of the semi-trailer acting on the left support leg; determining a second load of the semi-trailer acting on the right support leg; individually extending a support leg whose determined load is below an associated predetermined threshold; and enabling the opening of a coupling of the tractor to the semi-trailer if a load of the semi-trailer acting on the tractor is less than a predetermined further threshold.

[0008] A decoupling process can involve uncoupling the tractor from the trailer, i.e., severing a traction-locking connection between the tractor and the trailer. A fifth wheel coupling can be attached to the tractor and a king pin to the trailer, and the decoupling can involve opening the fifth wheel coupling so that the king pin can be removed from the fifth wheel coupling. The tractor can then drive away from the trailer.

[0009] It is possible to determine which of the support legs supports the lighter load, whereby only this support leg can be extended while the other leg remains stationary. This reduces the load on the energy source for extending the support legs. When determining the loads, a predetermined hysteresis, i.e., a tolerable deviation between the loads, can be taken into account to avoid excessive switching between the right and left support legs. The support legs can be extended gradually, allowing for better control of the correct position of the trailer.

[0010] Uncoupling of the tractor unit can only be authorized when the deviation between the loads acting on the support legs falls below a predetermined threshold. This ensures, in particular, that the trailer is not tilted too sharply laterally around its longitudinal axis during uncoupling. The trailer can be parked safely even if the ground is uneven and the distances the support legs must cover are unequal.

[0011] The support legs can be extended in such a way that uncoupling of the tractor is only permitted if the deviation between the effective lengths of the support legs is below a predetermined threshold. If the deviation exceeds the threshold, the trailer is tilted too much against gravity. If the support legs have to be extended to very different degrees to achieve the same load, this is an indication that the tractor is tilted. It is therefore advisable to check the difference in support leg stroke and prevent uncoupling if the deviation is too high.

[0012] The support legs can be extended in such a way that a deviation of an absolute roll angle of the trailer from the vertical falls below a predetermined threshold.

[0013] The absolute roll angle of a vehicle is typically defined as the orientation of the vehicle around its longitudinal axis. A vertical line, which corresponds to the direction of gravity, is typically used as a reference. When the vehicle is upright, its absolute roll angle is 0°. Monitoring the absolute roll angle can prevent the trailer from separating from the tractor unit when the vehicle is tilted too far.

[0014] For example, if the trailer is unevenly loaded along its longitudinal axis, an absolute roll angle of 0° cannot be achieved while the loads on the support legs are equal. Therefore, a predetermined deviation between the support loads can be tolerated to keep the absolute roll angle sufficiently low.

[0015] The support legs can be extended in such a way that the relative roll angle between the semi-trailer and the tractor unit falls below a predetermined threshold. A deviation in the roll angles of the vehicles can occur if the design of the fifth wheel coupling allows for a deviation when coupled. A relative roll angle between the tractor unit and the semi-trailer refers to a deviation in the alignment of the two vehicles about their roll axes. In other words, the relative roll angle can indicate how much one of the vehicles is twisted relative to the other. The relative roll angle can also be determined if the longitudinal axes of the vehicles do not intersect at a point or are offset from each other. The relative roll angle can be measured directly between the vehicles, or the absolute roll angles of both vehicles can be determined and subtracted from each other.For example, if the tractor is inclined by +5° and the trailer by -5° relative to the vertical, the relative roll angle between the vehicles can be +5° - (-5°) = 10°.

[0016] A load acting on a support leg can be determined based on a load acting on a wheel mounted on the same side as the support leg. In different embodiments, the wheel can be comprised of either the tractor or the trailer. A load acting on a left support leg can depend on a load acting on a left wheel of the trailer or a left wheel of the tractor. Similarly, a load acting on a right support leg of the semi-trailer can depend on a load acting on a right wheel of the trailer or a right wheel of the tractor. These relationships can each be linear. A load acting on a wheel can be determined, for example, using a dedicated sensor or based on a pressure in a pneumatic suspension at the wheel.A load acting on a support leg can be determined by taking into account the leverage ratios that exist between a wheel of the tractor and the support leg or between the support leg and a wheel of the semi-trailer.

[0017] According to a further aspect of the present invention, a control system for assisting a decoupling process of a semitrailer having a left and a right support leg from a tractor comprises: a first sensing device for determining loads of the semitrailer acting on the support legs, respectively; a left actuator for extending the left support leg; a right actuator for extending the right support leg; a control device for individually controlling the extension of a support leg whose associated load is below a predetermined threshold; and a second sensing device for determining a load of the semitrailer acting on the tractor. The control device is configured to enable opening of a coupling between the tractor and the semitrailer if the load of the semitrailer acting on the tractor is less than a predetermined further threshold.

[0018] The control device can be configured to carry out a method described herein in whole or in part. For this purpose, the processing device can be implemented electronically and comprise a programmable microcomputer or microcontroller, and the method can be in the form of a computer program product with program code means. The computer program product can also be stored on a computer-readable data carrier. Features or advantages of the method can be transferred to the device, or vice versa.

[0019] According to yet another aspect of the present invention, a vehicle comprises a control system as described herein. The vehicle may, in particular, comprise a tractor or a semi-trailer.

[0020] Yet another aspect of the present invention relates to a vehicle system having a tractor and a semi-trailer. The vehicle system, which may also be referred to as a semi-trailer, comprises a control system as described herein. The control system may be configured to support an automatic uncoupling process between the semi-trailer and the tractor. Components included in the control system may be provided alternatively on the tractor and / or on the semi-trailer.

[0021] A load acting on a support leg can be determined based on a load acting on a wheel of the trailer. In particular, a load acting on a wheel mounted on the same side as the support leg can be determined. Similarly, a load acting on both support legs together can be determined based on a total load, minus a load acting on the wheels of the trailer. The invention will now be described in more detail with reference to the accompanying figures, in which:

[0022] Figure 1 shows a vehicle system with a tractor and a semi-trailer;

[0023] Figure 2 shows an exemplary relative position of a tractor unit in relation to a semi-trailer;

[0024] Figure 3 a control system;

[0025] Figure 4 shows a flow diagram of a process.

[0026] Figure 1 shows a vehicle system 100 comprising a tractor unit 105 and a trailer 110. The tractor unit 105 can be separated from the trailer 110, for example, to be connected to another trailer 110. A vertical dashed line indicates the point at which the vehicles 105, 110 can be separated from each other. Connecting the vehicles 105, 110 is referred to as coupling, and separating them is referred to as uncoupling.

[0027] During uncoupling, the vehicles 105, 110 are standing on a surface 115 that is ideally flat and horizontal, but in practice is inclined, uneven, or capable of varying loads. A technique described herein relates to an uncoupling process between the vehicles 105, 110 even under such difficult conditions. For this purpose, the trailer 110 is supported in such a way that the tractor unit 105 can be uncoupled and driven away from the trailer 110.

[0028] Figure 2 shows an exemplary relative position of a tractor 105 relative to a semitrailer 110. The view shown corresponds to a longitudinal section through the vehicle system 100 of Figure 1 along a plane containing the dashed line. The vehicles 105, 110 are each symbolized here as squares. Each square is bisected both longitudinally and transversely by a dashed line, with a longitudinal axis 202 of the associated vehicle 105, 110 running through an intersection point of the dashed lines. It can be seen that the squares representing the vehicles 105, 110 are each rotated by an absolute roll angle 205 relative to a vertical. As a result, the vehicles 105, 110 are rotated relative to one another by a relative roll angle 210. The absolute roll angles 205 are opposite to one another, and the relative roll angle 210 can be determined as the deviation of the absolute roll angles 205.If the relative twisting is strong enough so that an amount of the relative roll angle 210 exceeds a predetermined threshold value, large forces may occur when uncoupling the tractor 105 from the trailer 110, which may endanger the stability of the vehicles 105, 110.

[0029] Also shown in Figure 2 is a relative height 215 between the tractor unit 105 and the trailer 110. The relative height 215 is represented here as the vertical distance between the longitudinal axes 202 of the vehicles 105 and 110. If the tractor unit 105 carries the load of the trailer 110, the relative height 215 is zero. For uncoupling, the tractor unit 105 can be lowered while the trailer 110 is supported on support legs. The relative height 215 assumes a value that is below a predetermined maximum value. After disconnecting the fifth wheel coupling, the tractor unit 105 can be driven away from the trailer 110.

[0030] It should be noted that in practice, the longitudinal axes of the vehicles 105, 110 are rarely exactly aligned with each other, but often form an angle with each other or are horizontally offset by a certain amount. The determination of the relative roll angle 210 or the relative height 215 in the area of ​​a coupling device between the tractor 105 and the trailer 110 can nevertheless be carried out in a manner described herein. Minor disturbances or inconsistencies in the determination of the relative roll angle or the relative height can be neglected.

[0031] Regarding values ​​and their comparison, a representation is given in the right-hand area of ​​Figure 2. A value 225 is determined on a predetermined scale 220. A value 225 that lies above the line designated zero is positive, a value 225 below it is negative. An absolute value 230 of a positive value 225 corresponds to the unchanged value 225; that of a negative value 225 corresponds to its value 225 multiplied by (-1). A value 225 can be compared with a range 235. In this case, the value 225 can relate in particular to a load. During the comparison, it can be determined whether the value 225 lies within or outside the range 235. Boundaries of the range 235 can be included in the range 235 or excluded from it. A value 225 can also be compared with a threshold value 240. It can be determined whether the value 225 is below, at or above the threshold value 240.A deviation 245 between a value 225 and another value, for example, a threshold value 240, can be determined as a numerical difference between corresponding numerical values ​​of the values ​​225. In various embodiments, the deviation 245 can be determined absolutely or as an amount 230.

[0032] Figure 3 shows a control system 300 for supporting an automatic uncoupling process of a tractor 105 from a trailer 110. The control system 300 is, by way of example, largely symmetrically constructed, in that some components are provided on both the tractor 105 and the trailer 110. It may be sufficient to provide such a component only on one side, i.e., only on the tractor 105 or only on the trailer 110. It should also be noted that some components that function similarly with respect to the present invention may be implemented differently on the tractor 105 and the trailer 110, as will be described in more detail below.

[0033] In the illustrated embodiment, the control system 300 on the tractor 105 side comprises a control device 305, a first sensor 310, a second sensor 315, and a first actuator 320 and a second actuator 325. In some embodiments, only one sensor 310, 315 or only one actuator 320, 325 is provided. Further preferably, an interface 330 is provided for communication with a component on the trailer 110 side. The interface 330 can be implemented wired or wirelessly.

[0034] The control device 305 can comprise a conventional control unit with a processing device. Optionally, the control device 305 is configured to perform tasks other than those described herein. It is also preferred that the control device 305 be connected to another component on board the tractor 105, in particular to allow interaction with the other component or a person. Further preferably, the control device 305 is configured to output a warning signal. In one embodiment, the warning signal can be output to a control unit or control system via an interface. In another embodiment, the warning signal can be output to a person in the area of ​​the vehicle system 100, in particular to a driver of the tractor 105.

[0035] The first sensor 310 is preferably fixedly attached to the tractor 105 and configured to scan the trailer 110. Scanning is more preferably performed contactlessly, for example, using an ultrasonic sensor, a radar sensor, or a LiDAR sensor. Optionally, a signal generator, a marker, or a reflective element is attached to the trailer 110 to facilitate scanning by the first sensor 310. A marker can be made of a retroreflective material, for example. The first sensor 310 can determine a relative orientation of the trailer 110 with respect to the tractor 105. The first sensor 310 is preferably provided in the region of a coupling device between the tractor 105 and the trailer 110.

[0036] The second sensor 315 may comprise an acceleration sensor, an inertial platform, or a similar sensor configured to determine an absolute roll angle of the tractor 105 with respect to the Earth's gravitational field. Optionally, the second sensor 315 may be sensitive about multiple axes and thus also determine a pitch angle or a yaw angle of the tractor 105.

[0037] The first actuator 320 is configured to control a height of a rear end of the tractor 105. Preferably, two first actuators 320 are provided, which can be actuated independently of one another to raise or lower the rear end of the tractor 105 either only on the left or only on the right. Purely by way of example, the first actuator 320 is depicted as an air bellows of a pneumatic chassis. The air bellows 320 elastically supports a wheel 322 of the tractor 105 and can control a height of the towing vehicle 105 above a surface on which the wheel 322 rests. Other implementations are also possible. The second actuator 325 is configured to influence a height and / or a roll angle of a coupling element for the semitrailer 110 on the tractor 105. The coupling element comprises, for example, a fifth wheel plate 335, which is preferably designed as a fifth wheel coupling plate.The second actuator 325 comprises, for example, two pneumatic or hydraulic actuators, one of which is provided on the left and one on the right side of the tractor 105. Other embodiments are also possible here.

[0038] In the embodiment shown, the semitrailer 110 includes a control device 305, a first sensor 310, a second sensor 315, and a first actuator 320, corresponding to the tractor 105. The functions of these components are described with reference to the components on the tractor 105 and can be applied accordingly on the semitrailer 110.

[0039] Two support legs 340 can be provided on the semi-trailer 110, one of which is attached to the front left in the direction of travel and the other to the front right in the direction of travel. The support legs 340 are configured to support a load in a front region of the semi-trailer 110 relative to the ground 115 when the front of the semi-trailer 110 is not resting on the fifth wheel plate 335 of the tractor unit 105. A support leg 340 comprises an actuator 342 for extending or retracting it, for example, pneumatically, hydraulically, or by electric motor. An effective length 344 of the support leg 340 can be changed in the vertical direction. If the support leg 340 rests on a ground, in some embodiments, a distance between a chassis of the semi-trailer 110 and the ground can be controlled by actuating the actuator 342. It is particularly preferred that the left support leg 340 and the right support leg 340 can each be extended and retracted independently of each other.Even more preferably, an associated load sensor 345 is provided on each of the support legs 340, which is configured to determine a load of the trailer 110 acting on the support leg 340.

[0040] Figure 4 shows a flowchart of a method 400. The method 400 can be executed by means of one or more interconnected control devices 405 of a vehicle system 100 and is configured to support a decoupling process of a tractor 110 from a trailer 115. In a step 405, a request for automatic decoupling of a tractor 105 from a trailer 110 can be determined. The request can be provided, for example, by a person or a control system on board one of the vehicles 105, 110. At this point in time, the tractor 105 and the trailer 110 are preferably connected to one another in a traction-locking manner, and a front end of the trailer 110 rests on a coupling device, in particular a fifth wheel plate 335, on a rear end of the tractor 105. The vehicles 105, 110 are stationary on the ground 115.Alternatively, a manually performed uncoupling process can be determined or started in this step.

[0041] In a step 410, support legs 340 of the trailer 110 can be extended. The purpose of the extension is to support a load of the trailer 110 at its front end against the ground 115, so that the tractor 105 can be relieved of load. The extension is preferably carried out by controlling actuators 342 of the support legs 340 accordingly.

[0042] In a step 415, effective loads of the trailer 110 on a right and a left side can be determined. A first determined load acts on the left support leg 340, a second load on the right support leg 340. The first and second loads can each be determined using an associated load sensor 345 on the respective support leg 340. Alternatively, the first or second load can be determined based on a total load of the trailer 110 less loads acting on wheels of the trailer 110. This determination can be performed summarily for both sides or separately for the right and left sides. Loads acting on the wheels can be determined, for example, via pneumatic pressures of an air suspension with which a chassis of the trailer 110 is supported relative to the wheels.

[0043] In one embodiment, the support legs 340 are initially extended simultaneously to the extent that they each make contact with the ground 115. It can be determined that a support leg 340 has reached the ground 115 when a load acting on the support leg 340 exceeds an assigned first threshold value 240. Typically, both support legs 340 are assigned the same first threshold values ​​240. If the ground 115 is uneven, the support legs 340 may have to bridge different vertical heights before the respective transmitted load reaches the first threshold value 240. Accordingly, the extension of the left support leg 340 and the extension of the right support leg 340 may take different amounts of time.

[0044] The support legs 340 can then be extended further to relieve the load on the tractor 105. To this end, a step 420 can determine whether the load acting on the left support leg 340 is greater than the load acting on the right support leg 340. If so, the right support leg 340 can be extended further in a step 425 while the left support leg 340 is stopped. Otherwise, the left support leg 340 can be extended further in a step 430 while the right support leg 340 is stopped. In other words, the support leg 340 that currently carries the lower load can be extended further.

[0045] If the trailer 110 is evenly loaded transversely and equal loads act on the left and right support legs 340, the absolute roll angle 210 of the trailer 110 with respect to gravity should be essentially zero. However, the absolute roll angle 210 may deviate from zero, for example, if one of the support legs 340 cannot be extended further before the support legs 340 have taken on a sufficient load.

[0046] During the extension of the support legs 340, the absolute roll angle 210 of the trailer 110 can therefore be determined using one or more of the sensors 310, 315. If the absolute roll angle 210 relative to the vertical or gravity exceeds an assigned threshold value 240, a warning signal can be issued. In this case, the method 400 can also be aborted in a step 450, as described in more detail below. Alternatively, an attempt can be made to minimize the absolute roll angle 210 by appropriately actuating the support legs 340. A predetermined inequality between the loads acting on the support legs 340 can be accepted. If the inequality between the support loads or the deviation of the roll angle of the trailer 110 from the vertical is too great, the method 400 can be aborted in step 450.

[0047] If the tractor 105 and the trailer 110 are parallel to a slope, the trailer 110 can be substantially vertical if the support loads on the support legs 340 are equal. However, the tractor 105 can be aligned with respect to the ground 115, so that a relative roll angle 210 can occur between the tractor 105 and the trailer 110.

[0048] During the extension of the support legs 340, the relative roll angle 210 between the tractor 105 and the trailer 110 can therefore be monitored. If the amount of the relative roll angle 210 exceeds an associated, predetermined threshold value 240, a warning signal can be issued. If an actuator 325 is available on the tractor 105, it can be controlled to pivot the tractor laterally and minimize the relative roll angle 210. The tractor 105 can also be raised laterally to the left or right to reduce the relative roll angle 210. The support legs 340 can also be actuated to reduce the relative roll angle 210. One of the compensating measures can accept a predetermined inequality between loads acting on the support legs 340. If the relative roll angle 210 or the inequality is too large, the method 400 can be aborted in step 450.

[0049] In one embodiment, the extension of the support legs 340 can be terminated when loads supported by the support legs 340 each exceed associated second threshold values ​​240. The second threshold values ​​240 are preferably selected to be equal. In this embodiment, the support legs 340 can also be extended simultaneously while their respective loads are between the associated first and second threshold values ​​240. The extension of a support leg 340 can be terminated when its supported load exceeds the associated second threshold value 240.

[0050] In another embodiment, the extension of the support legs 340 can be terminated in a step 435 depending on a load acting on the tractor 105. A corresponding sensor on the fifth wheel plate 435 of the tractor can be used to determine the load. Alternatively, the load acting on the tractor 105 can be determined based on a pneumatic pressure in an air suspension of wheels, in particular rear wheels, of the tractor 105. A load of the tractor 105 can be subtracted from a load determined in this way to determine the load of the semi-trailer. Optionally, leverage ratios between the rear wheels of the tractor 105, support legs 340, and rear wheels of the semi-trailer 110 can be taken into account to determine the load of the semi-trailer 110 acting on the support legs 340 based on a wheel or axle load.

[0051] If the load of the trailer 110 acting on the tractor 105 falls below an associated third threshold value 240, the support legs 340 can be stopped in a step 440. A lock between the tractor 105 and the trailer 110 can be released so that it can be uncoupled. The tractor 105 can be uncoupled from the trailer 110 manually or automatically. If the third threshold value 240 is greater than zero, the tractor 105 can be lowered to free itself as completely as possible from the support load of the trailer 110. The tractor 105 can then be driven forward away from the trailer 110.

[0052] If it was determined in step 435 that a load of the trailer 110 still rests on the tractor 105 that exceeds the third threshold value 240, a check can be performed in step 445 to determine whether a maximum adjustment range of the control system 400 has been reached. This can be the case, in particular, if one of the support legs 340 can no longer be extended. If this is not the case, the method 400 can continue in step 415.

[0053] Otherwise, the extension of the support legs 340 can be terminated in a step 450. In this case, the method 400 can end unsuccessfully in a step 455. The tractor 105 and the trailer 110 remain coupled to each other. Reference symbols (as part of the description):

[0054] 100 vehicle system

[0055] 105 tractor

[0056] 110 trailers

[0057] 115 Underground

[0058] 202 Longitudinal axis

[0059] 203 left side

[0060] 204 right side

[0061] 205 absolute roll angle

[0062] 210 relative roll angle

[0063] 215 relative height

[0064] 220 scale

[0065] 225 value, especially a load

[0066] 230 Amount

[0067] 235 area

[0068] 240 threshold

[0069] 245 Deviation

[0070] 300 tax system

[0071] 305 Control device

[0072] 310 first sensor

[0073] 315 second sensor

[0074] 320 first actuator

[0075] 325 second actuator

[0076] 330 interface

[0077] 335 saddle plate

[0078] 340 support leg

[0079] 342 Actuator of a support leg

[0080] 344 length

[0081] 345 Load sensor second method

[0082] Requirement for automatic uncoupling

[0083] Extend support legs

[0084] Determine the load on the trailer's support legs / wheels

[0085] Load left > load right?

[0086] Extend support leg to the right

[0087] Extend support leg left

[0088] Load on tractor?

[0089] Release tractor and trailer, maximum adjustment range reached?

[0090] stop

[0091] Release or open clutch

Claims

Patent claims:

1. A method (400) for assisting a decoupling operation of a tractor (105) from a trailer (110), wherein the trailer (110) comprises a left and a right support leg (340) that can be extended independently of one another; wherein the method (400) comprises the following steps: - determining (415) a first load of the trailer (110) acting on the left support leg (340); - determining (415) a second load of the trailer (110) acting on the right support leg (340); - individually extending (425, 430) a support leg (340) whose specific load (225) is below an associated predetermined threshold value (240); and - enabling (455) the opening of a coupling (335) of the tractor (105) with the semi-trailer (110) if a load (225) of the semi-trailer (110) acting on the tractor (105) is less than a predetermined further threshold value (240).

2. The method (400) of claim 1, wherein it is determined which of the support legs (340) supports the smaller load (225), and this support leg (340) is extended while the other support leg (340) is stopped.

3. Method (400) according to claim 1 or 2, wherein the uncoupling of the tractor (105) is only released (455) when an amount (230) of a deviation (245) between loads (225) acting on the support legs (340) falls below (435) a predetermined threshold value (240).

4. Method (400) according to one of the preceding claims, wherein the uncoupling of the tractor (105) is only released (455) if an amount (230) of a deviation (245) between effective lengths (344) of the support legs (340) is below a predetermined threshold value (240).

5. Method (400) according to one of the preceding claims, wherein the support legs (340) are extended such that a deviation (245) of a absolute roll angle (215) of the semi-trailer (110) from the vertical falls below a predetermined threshold value (240).

6. The method (400) according to any one of the preceding claims, wherein the support legs (340) are extended such that an amount (230) of a relative roll angle (210) between the semi-trailer (110) and the tractor (105) falls below a predetermined threshold value (240).

7. The method (400) of any preceding claim, wherein a load (225) acting on a support leg (340) is determined (415) based on a load (225) acting on a wheel (322) mounted on the same side as the support leg (340).

8. The method (400) of claim 7, wherein the wheel (322) is comprised by the tractor (105).

9. The method (400) of claim 7 or 8, wherein the wheel (322) is encompassed by the trailer (110).

10. A control system (300) for supporting a decoupling process of a semi-trailer (110) having a left and a right support leg (340) from a tractor (105), the control system (300) comprising: - a first sensing device (345) for determining loads of the trailer (110) which act on the support legs (340) respectively; - a left actuator (342) for extending the left support leg (340); - a right actuator (342) for extending the right support leg (340); - a control device (305) for individually controlling the extension of a support leg (340) whose associated load is below a predetermined threshold value (240); and - a second sensing device (320, 335) for determining a load of the trailer (110) acting on the tractor (105); - wherein the control device (305) is designed to enable opening of a coupling (335) of the tractor (105) with the trailer (110) if the load of the semi-trailer (110) acting on the tractor (105) is less than a predetermined further threshold value (240).

11. A vehicle (105, 110) comprising a control system (300) according to claim 10.

12. A vehicle system (105, 110) comprising a tractor (105) and a trailer (110) and a control system (300) according to claim 10.

Images