Driverless transport vehicle and method for operating a driverless transport vehicle

Description

[0001] The invention relates to an automated guided vehicle for transporting load carriers, in particular racks, which the automated guided vehicle can drive under, comprising a frame, a lifting device for raising a load carrier being driven under relative to the frame, and at least one laser scanner for detecting obstacles. The invention also relates to a method for operating an automated guided vehicle according to the invention.

[0002] Automated guided vehicles can be used in various facilities, such as supermarkets, industrial halls, logistics centers, hospitals, and production plants. Automated guided vehicles are used, for example, to transport objects, especially load carriers, within the respective facility. The load carriers serve to hold the goods to be transported.

[0003] Load carriers include racks or pallets, for example, which have one or more transport surfaces for holding goods. Such a load carrier has several support elements arranged beneath the transport surfaces and in contact with a floor on which the load carrier stands. Such support elements include, for example, fixed feet or rotating rollers. To pick up a load carrier, an automated guided vehicle moves underneath the load carrier and lifts it, causing the load carrier's support elements to lose contact with the floor.

[0004] The laser scanners capture the surroundings of the automated guided vehicle in a scanning plane above the ground. If the load carrier is raised only slightly, the support elements extend into the scanning plane of the laser scanners. Areas behind the support elements are then invisible to the laser scanners. Raising the load carrier above the scanning plane takes longer and causes the center of gravity to shift further upward. Transport vehicles should be as flat as possible, i.e., have the lowest possible height. Lifting devices with a correspondingly low height but a large lift are complex.

[0005] Document DE 10 2019 001 253 A1 discloses a method for operating a technical installation comprising an automated guided vehicle that can move along a traffic area of ​​the technical installation. The automated guided vehicle detects objects in the technical installation using appropriate sensors.

[0006] From DE 20 2020 000 762 U1 a driverless transport vehicle is known which has several 3D image sensors for detecting surveillance areas.

[0007] DE 10 2019 001 125 A1 discloses a conveyor system for conveying loaded or unloaded load carriers. The conveyor system consists of a first conveyor unit and a second conveyor unit. A sensor system is provided for detecting the surroundings of the conveyor system.

[0008] DE 10 2015 010 718 A1 discloses a conveyor system for conveying loaded or unloaded load carriers, comprising a first conveyor unit and a second conveyor unit. Each conveyor unit has a radar-based detection device.

[0009] DE 20 2019 106 154 U1 discloses an automated guided vehicle (AGV) and a transport arrangement comprising an AGV. The AGV has a platform designed to support loads and sensors for detecting obstacles.

[0010] The invention is based on the object of developing a driverless transport vehicle for transporting load carriers which can be driven under by the driverless transport vehicle, as well as a method for operating a driverless transport vehicle.

[0011] This object is achieved by a driverless transport vehicle having the features specified in claim 1. Advantageous embodiments and further developments are the subject of the subclaims. This object is achieved by a method for operating a driverless transport vehicle having the features specified in claim 13.

[0012] A driverless transport vehicle according to the invention for transporting load carriers, in particular racks, which the driverless transport vehicle can drive under, comprises a frame with an at least approximately rectangular cross-section with a front side, a rear side opposite the front side, a right longitudinal side, and a left longitudinal side opposite the right longitudinal side, wherein the front side and the rear side run in a transverse direction and the longitudinal sides run in a longitudinal direction, a lifting device for lifting a load carrier being driven under relative to the frame, and at least one laser scanner for detecting obstacles. A first laser scanner is arranged on the front side, a second laser scanner is arranged on the rear side, a third laser scanner is arranged on the right longitudinal side, and a fourth laser scanner is arranged on the left longitudinal side.The lifting device has a lifting plate for receiving the load carrier which is moved underneath and which is movable in a vertical direction relative to the frame.

[0013] If a support element of a load carrier being driven under protrudes into the scanning plane of a laser scanner, an area is created behind said support element which is not visible to the respective laser scanner. However, the laser scanners are arranged in such a way that in this case an area which is not visible to one laser scanner is largely visible to at least one other laser scanner. A hidden area which is not visible to any of the laser scanners has the shape of a triangle or a similar shape. The hidden area has a relatively small extent, which is defined by the position and size of the support elements. It is possible to keep the surface area of ​​the hidden area so small that people behind the support element can be detected. In contrast, with a classic arrangement of the laser scanners the area is open and expands in a fan-shaped manner with increasing distance from a support element.The surroundings of the automated guided vehicle are thus almost completely scanned by the laser scanners. With an automated guided vehicle according to the invention, it is possible to lift the load carrier only slightly for transport with a short lift. The short lift can be performed in a relatively short time, thus reducing the time required to pick up and lift the load carrier, thus achieving process time optimization.

[0014] According to the invention, the third laser scanner is arranged in a central area of ​​the right longitudinal side. According to the invention, the fourth laser scanner is arranged in a central area of ​​the left longitudinal side. This results in a symmetrical arrangement of the laser scanners with respect to the longitudinal sides.

[0015] According to the invention, all four laser scanners are used for navigation of the transport vehicle.

[0016] According to a preferred embodiment of the invention, the laser scanners are configured to detect obstacles in a respective scanning plane. The laser scanners are arranged on the frame such that the scanning planes of the laser scanners are aligned parallel to the floor on which the automated guided vehicle is located. This allows all significant obstacles in the system to be detected, and collisions with said obstacles can be avoided. An obstacle could be, for example, another automated guided vehicle, a person, or another object.

[0017] According to a preferred embodiment of the invention, the laser scanners are arranged on the frame such that the scanning planes of the laser scanners are at the same distance from the floor in a vertical direction. The scanning planes of the individual laser scanners thus coincide into a common scanning plane.

[0018] According to an advantageous development of the invention, the first laser scanner has a first field of view in the scanning plane, and the second laser scanner has a second field of view in the scanning plane, and the third laser scanner has a third field of view in the scanning plane, and the fourth laser scanner has a fourth field of view in the scanning plane. The first field of view and the second field of view extend in the respective scanning plane over an angular range of at least 200°, preferably of at least 230°. Thus, the first field of view and the second field of view also each extend into sections laterally of the transport vehicle.

[0019] According to a preferred development of the invention, the laser scanners are arranged on the frame in such a way that the first field of view and the third field of view overlap in a section which lies partially between the front side and the rear side in the longitudinal direction, and / or that the first field of view and the fourth field of view overlap in a section which lies partially between the front side and the rear side in the longitudinal direction, and / or that the second field of view and the third field of view overlap in a section which lies partially between the front side and the rear side in the longitudinal direction, and / or that the second field of view and the fourth field of view overlap in a section which lies partially between the front side and the rear side in the longitudinal direction. As a result, concealed areas behind supporting elements have relatively small dimensions.

[0020] According to a preferred embodiment of the invention, the longitudinal sides are longer than the front and rear sides, in particular at least twice as long. The distance between the front and rear sides in the longitudinal direction is thus greater than the distance between the longitudinal sides in the transverse direction.

[0021] According to an advantageous embodiment of the invention, the first laser scanner is arranged in a central area of ​​the front. According to an advantageous embodiment of the invention, the second laser scanner is arranged in a central area of ​​the rear. This results in a symmetrical arrangement of the laser scanners with respect to the front and rear. Advantageously, the concealed area behind the support elements of a load carrier being driven under is particularly small. With this arrangement, all four laser scanners should be used for navigation, since the first laser scanner and the second laser scanner cover the long sides to a lesser extent.

[0022] According to a further advantageous embodiment of the invention, the first laser scanner is arranged in a corner region of the front side and a long side. According to a further advantageous embodiment of the invention, the second laser scanner is arranged in a corner region of the rear side and a long side. This arrangement of the laser scanners enables improved navigation of the driverless transport vehicle using the laser scanners. In particular, navigation is possible exclusively via the first laser scanner and the second laser scanner, since their combined field of view covers a relatively large area on the long sides of the transport vehicle. The third laser scanner and the fourth laser scanner can then be pure safety scanners that are not used for navigation.

[0023] According to a preferred development of the invention, the lifting device comprises a lifting plate for receiving a load carrier that is moved underneath, which is movable in a vertical direction relative to the frame, and which comprises a centering device for centering a load carrier that is moved underneath. Thus, a raised load carrier is held positively on the automated guided vehicle and secured against slipping. Positioning tolerances of a load carrier that is moved underneath can thus be compensated, thereby increasing process reliability.

[0024] According to an advantageous development of the invention, the automated guided vehicle comprises a safety controller configured to generate a warning message when at least one laser scanner detects an obstacle in its field of view. An obstacle could be, for example, another automated guided vehicle, a person, or another object. Upon detection of an obstacle, it is conceivable that the safety controller performs additional actions in addition to generating the warning message, for example, braking the automated guided vehicle to prevent a collision.

[0025] According to a preferred embodiment of the invention, the driverless transport vehicle comprises a drive device, an electrical energy storage device for supplying the drive device, and a control unit for controlling the drive device. The drive device comprises, for example, an electric motor, a transmission, and drive wheels.

[0026] According to a further advantageous embodiment of the invention, the automated guided vehicle comprises a position sensor for detecting the position of the automated guided vehicle. Said sensor is, for example, a GPS receiver. Detecting the position of the automated guided vehicle enables easy localization of the automated guided vehicle. Additionally, detecting the position of the automated guided vehicle using laser scanners and / or RFID is conceivable.

[0027] According to a method according to the invention for operating an automated guided vehicle according to the invention, a load carrier to be transported, in particular a frame, is driven under by the automated guided vehicle, and the underdriven load carrier is lifted relative to the frame by the lifting device. The load carrier is then transported while at least one support element of the load carrier extends into a scanning plane of the laser scanner.

[0028] With the method according to the invention, it is sufficient to lift the load carrier only slightly for transport with a short stroke. The short stroke is performed in a relatively short time, thus reducing the time required to pick up and lift the load carrier. This achieves process time optimization.

[0029] The invention is not limited to the combination of features in the claims. Further possible combinations of claims and / or individual claim features and / or features of the description and / or the figures will become apparent to those skilled in the art, particularly from the problem and / or the problem posed by comparison with the prior art.

[0030] The invention will now be explained in more detail with reference to the accompanying drawings. The invention is not limited to the exemplary embodiments shown in the drawings. The drawings only schematically depict the subject matter of the invention. They show: Figure 1: a semi-transparent top view of a driverless transport vehicle according to a first embodiment with a load carrier, Figure 2: a further semi-transparent top view of a driverless transport vehicle according to the first embodiment with a load carrier, Figure 3: a semi-transparent top view of a driverless transport vehicle according to a second embodiment with a load carrier and Figure 4: a perspective view of a driverless transport vehicle according to the second embodiment with a load carrier.

[0031] Figure 1shows a semi-transparent plan view of a driverless transport vehicle 10 according to a first embodiment with a load carrier 50. The driverless transport vehicle 10 is located on a flat floor 5, which extends at right angles to a vertical direction Z. A transverse direction Y extends at right angles to the vertical direction Z. A longitudinal direction X extends at right angles to the vertical direction Z and at right angles to the transverse direction Y.

[0032] The automated guided vehicle 10 comprises a frame 20 with an approximately rectangular cross-section. The frame 20 has a front side 21, a rear side 22 opposite the front side 21, a right longitudinal side 23, and a left longitudinal side 24 opposite the right longitudinal side 23. The front side 21 and the rear side 22 extend in the transverse direction Y, while the long sides 23, 24 extend in the longitudinal direction X. The long sides 23, 24 are longer than the front side 21 and the rear side 22, for example, 1.5 times as long, twice as long, 2.5 times as long, or three times as long.

[0033] The automated guided vehicle 10 comprises a first laser scanner 11, which is arranged in a central area of ​​the front side 21. The automated guided vehicle 10 comprises a second laser scanner 12, which is arranged in a central area of ​​the rear side 22. The automated guided vehicle 10 comprises a third laser scanner 13, which is arranged in a central area of ​​the right longitudinal side 23. The automated guided vehicle 10 comprises a fourth laser scanner 14, which is arranged in a central area of ​​the left longitudinal side 24. All four laser scanners 11, 12, 13, 14 are used for the navigation of the transport vehicle 10.

[0034] The laser scanners 11, 12, 13, 14 each emit a laser beam in a scanning plane, detect a reflected laser beam, and use this to calculate a distance to an object reflecting the respective laser beam. The laser scanners 11, 12, 13, 14 are particularly designed to detect obstacles in the respective scanning plane. The laser scanners 11, 12, 13, 14 are arranged on the frame 20 such that the scanning planes of the laser scanners 11, 12, 13, 14 are aligned parallel to the ground 5 on which the automated guided vehicle 10 is located. The scanning planes of the laser scanners 11, 12, 13, 14 are at the same distance from the ground 5 and thus coincide to form a common scanning plane.

[0035] The first laser scanner 11 has a first field of view S1 in the scanning plane, in which obstacles can be detected by the first laser scanner 11. The second laser scanner 12 has a second field of view S2 in the scanning plane, in which obstacles can be detected by the second laser scanner 12. The third laser scanner 13 has a third field of view S3 in the scanning plane, in which obstacles can be detected by the third laser scanner 13. The fourth laser scanner 14 has a fourth field of view S4 in the scanning plane, in which obstacles can be detected by the fourth laser scanner 14.

[0036] The automated guided vehicle 10 comprises a lifting device for raising a load carrier 50 relative to the frame 20. The lifting device has a lifting plate 32 for receiving a load carrier 50. The lifting plate 32 is movable relative to the frame 20 in the vertical direction Z. In the illustration shown here, a load carrier 50 is located on the automated guided vehicle 10.

[0037] The load carrier 50 is embodied as a frame and comprises a transport surface 58 extending perpendicular to the vertical direction Z. The transport surface 58 serves to accommodate goods to be transported, for example, crates or cartons. Said transport surface 58 of the load carrier 50 rests on the lifting plate 32 of the driverless transport vehicle 10. It is also conceivable for the load carrier 50 to have a plurality of transport surfaces 58 arranged one above the other in the vertical direction Z.

[0038] The load carrier 50, designed as a frame, further comprises four support elements 51. The support elements 51 are arranged below the aforementioned transport surface 58. When the load carrier 50 stands on the floor 5, the support elements 51 are in contact with the floor 5. In this case, the support elements 51 are designed as rotatable rollers. The aforementioned rollers are each rotatable about a rotation axis that runs perpendicular to the vertical direction Z. The aforementioned rollers are additionally each pivotable about a pivot axis that runs in the vertical direction Z. The rotation axis and the pivot axis of such a roller do not intersect in this case, but are spaced apart from one another.

[0039] In this case, the load carrier 50 is slightly raised by the lifting device of the automated guided vehicle 10. The support elements 51 are thus removed from the floor 5, but extend into the scanning planes of the laser scanners 11, 12, 13, 14. The support elements 51 are opaque to the laser beams of the laser scanners 11, 12, 13, 14. By pivoting 360° around the respective pivot axis, each roller defines a circular area 55 that is opaque to the laser scanners 11, 12, 13, 14.

[0040] The opaque regions 55 formed by the support elements 51 of the load carrier 50 each delimit the fields of view S1, S2, S3, S4 of the laser scanners 11, 12, 13, 14. The fields of view S1, S2, S3, S4 are each delimited by two boundary lines B that are tangent to the opaque regions 55. Two boundary lines B of adjacent laser scanners 11, 12, 13, 14 each intersect at an intersection point K. The intersection points K are each located on the sides of the opaque regions 55 facing away from the laser scanners 11, 12, 13, 14.

[0041] Two fields of view S1, S2, S3, S4 of adjacent laser scanners 11, 12, 13, 14 overlap in sections that lie on the sides of the intersection points K facing away from the laser scanners 11, 12, 13, 14. A concealed area V is formed between each intersection point K and an associated opaque area 55. The concealed areas V are located outside the fields of view S1, S2, S3, S4. The areas of the concealed areas V are relatively small and each have an approximately triangular shape.

[0042] Figure 2 shows a further semi-transparent plan view of a driverless transport vehicle 10 according to the first embodiment with a load carrier 50. The driverless transport vehicle 10 is identical to the one in Figure 1shown driverless transport vehicle 10. In the illustration shown here, a load carrier 50 is located on the driverless transport vehicle 10, which differs from the one shown in Figure 1 shown load carrier 50.

[0043] The load carrier 50, designed as a frame, also comprises four support elements 51 arranged below the transport surface 58. When the load carrier 50 stands on the floor 5, the support elements 51 are in contact with the floor 5. In this case, the support elements 51 are designed as fixed feet. The support elements 51 have an approximately square cross-section.

[0044] In this case, the load carrier 50 is slightly raised by the lifting device of the automated guided vehicle 10. The support elements 51 are thus spaced away from the floor 5, but extend into the scanning planes of the laser scanners 11, 12, 13, 14. The support elements 51 are opaque to the laser beams of the laser scanners 11, 12, 13, 14 and each defines an opaque area 55 for the laser scanners 11, 12, 13, 14.

[0045] The opaque regions 55 formed by the support elements 51 of the load carrier 50 each delimit the fields of view S1, S2, S3, S4 of the laser scanners 11, 12, 13, 14. The fields of view S1, S2, S3, S4 are each delimited by two boundary lines B that are tangent to the opaque regions 55. Two boundary lines B of adjacent laser scanners 11, 12, 13, 14 each intersect at an intersection point K. The intersection points K are each located on the sides of the opaque regions 55 facing away from the laser scanners 11, 12, 13, 14.

[0046] Two fields of view S1, S2, S3, S4 of adjacent laser scanners 11, 12, 13, 14 overlap in sections that lie on the sides of the intersection points K facing away from the laser scanners 11, 12, 13, 14. A concealed area V is formed between each intersection point K and an associated opaque area 55. The concealed areas V are located outside the fields of view S1, S2, S3, S4. The areas of the concealed areas V are relatively small and each have a triangular shape.

[0047] Figure 3 shows a semi-transparent plan view of a driverless transport vehicle 10 according to a second embodiment with a load carrier 50. The driverless transport vehicle 10 according to the second embodiment largely corresponds to the one shown in Figure 1 and in Figure 2illustrated driverless transport vehicle 10 according to the first embodiment. The driverless transport vehicle 10 according to the second embodiment differs from the driverless transport vehicle 10 according to the first embodiment in the arrangement of the laser scanners 11, 12, 13, 14. These differences will be discussed primarily below.

[0048] The automated guided vehicle 10 comprises a first laser scanner 11, which is arranged in a corner region of the front side 21 and the first longitudinal side 23. The automated guided vehicle 10 comprises a second laser scanner 12, which is arranged in a corner region of the rear side 22 and the second longitudinal side 24. The automated guided vehicle 10 comprises a third laser scanner 13, which is arranged in a central region of the right longitudinal side 23. The automated guided vehicle 10 comprises a fourth laser scanner 14, which is arranged in a central region of the left longitudinal side 24. The first laser scanner 11 and the second laser scanner 12 are arranged in diagonally opposite corner regions of the frame 20. The first laser scanner 11 and the second laser scanner 12 are used for the navigation of the transport vehicle 10.

[0049] The load carrier 50 shown here is identical to the one in Figure 2The load carrier 50 is designed as shown and comprises four support elements 51 arranged below the transport surface 58. When the load carrier 50 stands on the floor 5, the support elements 51 are in contact with the floor 5. The support elements 51 are designed as fixed feet. The support elements 51 have an approximately square cross-section.

[0050] In this case, the load carrier 50 is slightly raised by the lifting device of the automated guided vehicle 10. The support elements 51 are thus spaced away from the floor 5, but extend into the scanning planes of the laser scanners 11, 12, 13, 14. The support elements 51 are opaque to the laser beams of the laser scanners 11, 12, 13, 14 and each defines an opaque area 55 for the laser scanners 11, 12, 13, 14.

[0051] The opaque regions 55 formed by the support elements 51 of the load carrier 50 each delimit the fields of view S1, S2, S3, S4 of the laser scanners 11, 12, 13, 14. The fields of view S1, S2, S3, S4 are each delimited by two boundary lines B that are tangent to the opaque regions 55. Two boundary lines B of adjacent laser scanners 11, 12, 13, 14 each intersect at an intersection point K. The intersection points K are each located on the sides of the opaque regions 55 facing away from the laser scanners 11, 12, 13, 14.

[0052] Two fields of view S1, S2, S3, S4 of adjacent laser scanners 11, 12, 13, 14 overlap in sections that lie on the sides of the intersection points K facing away from the laser scanners 11, 12, 13, 14. A concealed area V is formed between each intersection point K and an associated opaque area 55. The concealed areas V are located outside the fields of view S1, S2, S3, S4. The areas of the concealed areas V are relatively small and each have a triangular shape.

[0053] Figure 4 shows a perspective view of a driverless transport vehicle 10 according to the second embodiment with a load carrier 50. The driverless transport vehicle 10 is identical to the one shown in Figure 3 shown driverless transport vehicle 10. In the illustration shown here, a load carrier 50 is located on the driverless transport vehicle 10, which is identical to the one shown in Figure 3shown load carrier 50 is formed.

[0054] The automated guided vehicle 10 is located on a flat floor 5, which extends perpendicular to the vertical direction Z. In this case, the load carrier 50 is slightly raised by the lifting device of the automated guided vehicle 10. The support elements 51 are thus spaced from the floor 5, but extend into the scanning planes of the laser scanners 11, 12, 13, 14. List of reference symbols

[0055] 5Floor 10Automated Guided Vehicle 11First laser scanner 12Second laser scanner 13Third laser scanner 14Fourth laser scanner 20Frame 21Front 22Rear 23Right long side 24Left long side 32Lifting plate 50Load carrier 51Supporting element 55Opaque area 58Transport area BBoundary line KIntersection point S1First field of vision S2Second field of vision S3Third field of vision S4Fourth field of vision VConcealed area XLongitudinal direction YTransverse direction ZVertical direction

Claims

1. A driverless transport vehicle (10) for transporting load carriers (50), in particular frames, under which the driverless transport vehicle (10) can drive, comprising a frame (20), with an at least substantially rectangular cross-section with a front side (21), a rear side (22) opposite the front side (21), a right-hand long side (23) and a left-hand long side (24) opposite the right-hand long side (23), wherein the front side (21) and the rear side (22) run in a transverse direction (Y) and the long sides (23, 24) run in a longitudinal direction (X), a lifting device for raising a driven-under load carrier (50) relative to the frame (20) and at least one laser scanner (11, 12, 13, 14) for identifying obstacles, wherein a first laser scanner (11) is arranged at the front side (21), a second laser scanner (12) is arranged at the rear side (22), a third laser scanner (13) is arranged at the right-hand long side (23) and a fourth laser scanner (14) is arranged at the left-hand long side (24), wherein all four laser scanners (11, 12, 13, 14) are used for the navigation of the transport vehicle (10), characterised in that the lifting device has a lifting plate (32) for receiving the driven-under load carrier (50), which lifting plate is movable in a vertical direction (Z) relative to the frame (20), and in that the third laser scanner (13) is arranged in a central region of the right-hand long side (23), and in that the fourth laser scanner (14) is arranged in a central region of the left-hand long side (24).

2. A driverless transport vehicle (10) according to claim 1, characterised in that the laser scanners (11, 12, 13, 14) are designed to identify obstacles in a respective scanning plane, wherein the laser scanners (11, 12, 13, 14) are arranged on the frame (20) such that the scanning planes of the laser scanners (11, 12, 13, 14) are oriented parallel to ground (5) on which the driverless transport vehicle (10) is located.

3. A driverless transport vehicle (10) according to claim 2, characterised in that the laser scanners (11, 12, 13, 14) are arranged on the frame (20) such that the scanning planes of the laser scanners (11, 12, 13, 14) are at the same distance from the ground (5) in a vertical direction (Z).

4. A driverless transport vehicle (10) according to one of claims 2 to 3, characterised in that the first laser scanner (11) has a first field of view (S1) in the scanning plane, and in that the second laser scanner (12) has a second field of view (S2) in the scanning plane, and in that the third laser scanner (13) has a third field of view (S3) in the scanning plane, and in that the fourth laser scanner (14) has a fourth field of view (S4) in the scanning plane, and in that the first field of view (S1) and the second field of view (S2) extend in the respective scanning plane over an angular range of at least 200°, preferably at least 230°.

5. A driverless transport vehicle (10) according to claim 4, characterised in that the laser scanners (11, 12, 13, 14) are arranged on the frame (20) such that the first field of view (S1) and the third field of view (S3) overlap in a portion which in a longitudinal direction (X) lies partially between the front side (21) and the rear side (22), and / or in that the first field of view (S1) and the fourth field of view (S4) overlap in a portion which in a longitudinal direction (X) lies partially between the front side (21) and the rear side (22), and / or in that the second field of view (S2) and the third field of view (S3) overlap in a portion which in a longitudinal direction (X) lies partially between the front side (21) and the rear side (22), and / or in that the second field of view (S2) and the fourth field of view (S4) overlap in a portion which in a longitudinal direction (X) lies partially between the front side (21) and the rear side (22).

6. A driverless transport vehicle (10) according to any one of the preceding claims, characterised in that the long sides (23, 24) are longer than the front side (21) and the rear side (22), in particular at least twice as long.

7. A driverless transport vehicle (10) according to any one of the preceding claims, characterised in that the first laser scanner (11) is arranged in a central region of the front side (21), and / or in that the second laser scanner (12) is arranged in a central region of the rear side (22).

8. A driverless transport vehicle (10) according to any one of the preceding claims, characterised in that the first laser scanner (11) is arranged in a corner region of the front side (21) and a long side (23, 24), and / or in that the second laser scanner (12) is arranged in a corner region of the rear side (22) and a long side (23, 24).

9. A driverless transport vehicle (10) according to any one of the preceding claims, characterised in that the lifting plate (32) has a centring device for centring a driven-under load carrier (50).

10. A driverless transport vehicle (10) according to any one of the preceding claims, characterised in that the driverless transport vehicle (10) comprises a safety control means which is configured to generate a warning when at least one laser scanner (11, 12, 13, 14) identifies an obstacle in a field of view (S1, S2, S3, S4).

11. A driverless transport vehicle (10) according to any one of the preceding claims, characterised in that the driverless transport vehicle (10) comprises a drive arrangement, an electrical energy store to supply the drive arrangement and a control unit to control the drive arrangement.

12. A driverless transport vehicle (10) according to any one of the preceding claims, characterised in that the driverless transport vehicle (10) comprises a position sensor to identify a position of the driverless transport vehicle (10).

13. A method of operating a driverless transport vehicle (10) according to any one of the preceding claims, characterised in that a load carrier (50) to be transported, in particular a frame, is driven under by the driverless transport vehicle (10); the driven-under load carrier (50) is raised relative to the frame (20) by the lifting device; and transport of the load carrier (50) is carried out, while at least one support element (51) of the load carrier (50) projects into a scanning plane of the laser scanners (11, 12, 12, 14).