System for transporting objects in an installation having a plurality of stations

Abstract

The present invention relates to a system (100) for transporting objects in an installation (10) having a plurality of stations (M1-M4), in particular a packaging machine installation, comprising at least one driverless transport vehicle (12) configured to transport objects between the stations (M1-M4), a central control unit (14) that is communicatively coupled to the at least one transport vehicle (12) and the stations (M1-M4) and is configured to coordinate the operation of the at least one transport vehicle (12) and, if necessary, the stations (M1-M4), a driveable underlying surface (16) on which the at least one driverless transport vehicle (12) moves, and at least one detection unit (12a) that is configured to detect at least the driveable underlying surface (16) in order to determine a position of the at least one driverless transport vehicle (12) within the installation (10), the driveable underlying surface (16) comprising a plurality of driving surface modules (16a) whose upper side is provided with an identical two-dimensional pattern that makes it possible, when a surface section with predetermined dimensions is detected, to unambiguously determine a position thereof in a coordinate system of the driving surface module (16a). The invention further relates to an installation (10) comprising such a system (100), and to a method for determining a position of a transport vehicle (12) in such an installation.

Description

[0001] 221349PDE / FEHHslo 1

[0002] System for transporting objects in a facility with multiple stations

[0003] Description

[0004] The present invention relates to a system for transporting objects in a plant with a plurality of stations, in particular a packaging machine plant, as well as such a plant and a method for determining a position of a transport vehicle in such a plant.

[0005] In systems with multiple stations, and especially in packaging machine systems, the purpose is generally to supply objects to the individual stations in a predetermined sequence, where they are processed or handled accordingly. In the specific case of a packaging machine system, this involves the precise positioning of products delivered by a production machine on a conveyor belt into packaging, such as cardboard boxes, which is in turn carried out by means of so-called robotic lines.

[0006] In this process, open primary packaging, such as tray-shaped containers, which are erected and three-dimensionally fixed from flat cardboard blanks upstream but already within the machine, travel on a container conveyor, usually parallel to the product conveyor in the direction of travel through the packaging machine. Several transfer robots are typically arranged in series as handling units, each picking up one or more products from the product conveyor and transferring them into the primary packaging, such as the tray, on the container conveyor.

[0007] Further downstream, these primary packages are often transferred in one or more layers into secondary packages, such as open-top cartons, which is also usually done using transfer robots. Even further downstream (221349PDE / FEHHslo 2), such secondary packages are often combined into tertiary packages, for example, stacked on pallets, mostly also by robots. The necessary handling operations are carried out at the individual workstations within the packaging line, such as tray separators, blank separators, carton erectors, carton closers, tray fillers, carton fillers, palletizers, etc.

[0008] The transport system used for this purpose can include, in addition to the aforementioned product belt and / or container belt, i.e. conveyor belts, which usually extend over sections of the entire length of the packaging line, also rail-bound sleds, whereby these rails, which can be designed as physical or virtual non-visible guiding devices, usually also extend along the entire length of the packaging line.

[0009] Although in the latter solution the carriages can already move independently of each other along the guide rails, such transport systems are still comparatively inflexible, since these carriages, for example, cannot overtake each other, cannot deviate from the guide rails and are also relatively expensive to purchase, so that a limited number of carriages are used and thus the carriages do not offer any significant buffering capacity for, for example, packaging placed on them.

[0010] Especially when the underlying work order changes—not just the product being processed, but a fundamental change to the processing or handling tasks related to the product and / or the packaging process—such known transport systems are unsuitable, as they require a complex reconfiguration of the conveyor belts or guide rails, or even a complete rebuild within the packaging machines. Furthermore, these transport systems are not suitable for spontaneously removing defective products or outer packaging from the system at various points, unless they were specifically designed for such operational processes, which also entails considerable additional effort. 221349PDE / FEHHslo 3

[0011] It should be noted that although the scenario described above mainly refers to a packaging machine system, similar requirements and tasks also arise in other types of systems with multiple stations, in which products are processed in different ways at individual stations and must therefore be transported between individual stations during the processing process.

[0012] For such tasks, some production plants and logistics facilities have meanwhile started using so-called driverless transport systems, in which driverless transport vehicles, which are often also referred to as FTF or AGV (Autonomous Guided Vehicles), transport objects or products, such as components or assemblies, from a warehouse to a workstation or between workstations, often also outside the secured machine frames of the workstations.

[0013] These AGVs are typically large and heavy, capable of carrying loads of 50 kg or more. Most importantly, they are usually autonomous vehicles equipped with a wide range of sensors, their own on-board control system, and often even on-board navigation with position determination based on the environment via on-board cameras, as well as collision avoidance systems. This makes them expensive and complex to maintain. Furthermore, such systems typically include a central control unit, such as a control center, with which the AGVs communicate wirelessly and from which they receive, for example, work orders or information about their own positions within the facilities.

[0014] Most of these AGVs, however, determine their position independently using sensors and reference points and transmit this information to the central control system, which usually specifies transport orders with a start and end point as well as a start and end time, but often leaves the navigation between them to the AGVs' on-board control system, as well as a real-time calculation (221349PDE / FEHHslo 4).

[0015] Collision prevention based on locally acquired information about the surroundings of the vehicles in question.

[0016] To ensure the smooth execution of planned operational processes, the position tracking of the AGVs is of crucial importance, as only if these driverless transport vehicles can determine their own position with high accuracy can work orders be processed smoothly and according to schedule. As already mentioned, relatively complex and expensive systems are often used for this purpose, such as 2D cameras with subsequent image recognition, which enables a comparison with environmental data stored in a memory unit of the transport vehicle's control system in the form of map data.Accordingly, it would be desirable to provide alternative systems and techniques for determining the position of transport vehicles in a work environment, which are simpler and more cost-effective compared to currently used systems, but allow a similarly reliable determination of the position of a transport vehicle.

[0017] To solve this problem and to eliminate the disadvantages of the known prior art described above, the invention proposes a system for transporting objects in a plant with a plurality of stations, in particular a packaging machine plant, comprising at least one driverless transport vehicle which is equipped to transport objects between the stations, a central control unit which is communicatively coupled with the at least one transport vehicle and the stations and is equipped to control the operation of the at least one transport vehicle and, if applicable,to coordinate the stations, a drivable surface on which the at least one driverless transport vehicle moves, and at least one detection unit which is designed to detect at least the drivable surface in order to determine a position of the at least one driverless transport vehicle within the system, wherein the drivable surface comprises a plurality of driving surface modules which are provided on their upper surface with an identical two-dimensional pattern which, when detecting a surface section with predetermined dimensions thereof, enables a unique determination of a position in a coordinate system of the driving surface module.

[0018] Accordingly, in the language of the present application, the central control unit represents a control center of the system, and the determination of the position of a corresponding vehicle is carried out at least by recording a section of the drivable surface with predetermined dimensions, which depend on the design and positioning of the recording unit used and which will be reflected in the design of the two-dimensional pattern on the road surface modules.While such a pattern is in principle suitable for capturing any position on its surface using unique coordinates, it must be considered that the pattern's uniqueness can only be guaranteed up to a certain maximum area size, depending on the size of the captured area section with its predetermined dimensions. If these predetermined dimensions are exceeded, the features of the two-dimensional pattern would repeat. A unique assignment of the captured pattern to corresponding coordinates in the coordinate system of the surface module would then no longer be possible. On the other hand, a flexible design of the overall driving surface is possible by combining the standardized and identical driving surface modules, since the identification of connection points allows for the detection and evaluation of transitions between corresponding driving surface modules.

[0019] Furthermore, the two-dimensional pattern on the majority of driving surface modules can be designed in such a way that, when it is detected, it also enables the determination of an angle to the coordinate system of the driving surface module, with possible designs of a suitable two-dimensional pattern being discussed in detail below.

[0020] Furthermore, the drivable surface can comprise a plurality of road surface modules with different dimensions, whereby road surface modules with the same 221349PDE / FEHHslo 6

[0021] The dimensions of the two-dimensional modules are identical. This makes it possible to completely cover even irregularly shaped driving areas of the system's surface with corresponding driving surface modules. Of course, combinations of driving surface modules with different dimensions within a single system are also conceivable, each featuring different but identical two-dimensional patterns.

[0022] In principle, one way to implement the present invention is to assign at least one of the detection units to each of the transport vehicles. This detection unit is operationally coupled to a control unit of the respective transport vehicle, which in turn is configured to determine the current position on the corresponding driving surface module based on the area of ​​the driving surface detected by the detection unit. The aforementioned control unit of the transport vehicle can be integrated with or operationally coupled to a main control unit of the transport vehicle, so that the corresponding localization system can either be directly integrated into the rest of the control logic of the transport vehicle or coupled to it as a separate module.

[0023] Furthermore, the corresponding control unit of the transport vehicle can have access to a map of the system stored in a memory unit, which enables the coordinate systems of the driving surface modules to be assigned to a coordinate system of the system. In this way, a logical connection is created between the local coordinate systems of the individual driving surface modules and the global coordinate system of the entire system. However, embodiments of the invention are also conceivable in which the use of such a map is dispensed with and, for example, the paths to be traveled by transport vehicles are encoded solely on the basis of the local coordinate systems of the individual driving surface modules and the transitions between them.

[0024] In particular, the control unit of the transport vehicle may also be configured to allow a transition of the transport vehicle from a 221349PDE / FEHHslo 7

[0025] to determine the driving surface module to another during a movement of one of them, whereby corresponding information then not only allows a transition into a local coordinate system of the subsequently traversed driving surface module, but also, for example, a tracking of the current position of the transport vehicle in the global coordinate system.

[0026] Furthermore, at least one transport vehicle can also include a localization unit capable of determining on which of the track modules the transport vehicle is currently located, particularly during commissioning. Various approaches are conceivable for this; however, it should be noted that such localization of a track module on which the transport vehicle is currently located can be performed with significantly lower precision than the actual position determination within the coordinate system of the corresponding track module, which was described previously.Accordingly, significantly more cost-effective localization units can be used here than in systems known from the prior art, for example, low-resolution position transmitters and receivers or low-resolution camera systems installed in the system. The central control unit could then use the external camera system to record the position of the transport vehicle relative to the current track module and transmit it to the transport vehicle. As mentioned, such initial localization of the track module being traversed is particularly necessary when commissioning a transport vehicle, since at that point the vehicle has no reference point for its own absolute position in the environment.In subsequent operation, the detection of transitions between the driving surface modules can then permanently ensure that the corresponding transport vehicle always knows which of the driving surface modules it is currently on, or where it is currently located in the global coordinate system of the entire system.

[0027] Regarding the design of the 221349PDE / FEHHslo 8 assigned to the transport vehicles

[0028] Regarding the detection units, and thus also the formation of the two-dimensional pattern on the road surface, it can generally be said that optical, magnetic, or capacitive systems can be used. Accordingly, the aforementioned detection units could be camera units, magnetic sensor units, or capacitive sensor units, and the two-dimensional patterns could be optical, magnetic, or capacitive markings on or attached to the road surface modules, which can be read from above.

[0029] Furthermore, according to the invention, it is conceivable to provide at least one of the detection units installed outside the transport vehicles in the system, which can accordingly be configured to detect at least one of the driving surface modules and the transport vehicles located thereon, wherein this detection unit can preferably be designed as a camera unit. In this way, too, the current position of the transport vehicle can be determined using the two-dimensional pattern of the corresponding driving surface module, wherein the corresponding at least one detection unit can communicate either with the central control unit or directly with the at least one transport vehicle in order to provide corresponding data.Alternatively or additionally, such a detection unit can also be used to simply determine on which driving surface module a transport vehicle is currently located, in order to then provide the corresponding data to the transport vehicle for subsequent self-localization.

[0030] A particularly advantageous design of the two-dimensional pattern can consist of a binary-coded, continuous code in two dimensions; that is, in simplified terms, two barcode-like patterns intersecting at an angle, from which unique X and Y coordinates can be derived. Such a pattern is characterized by its high robustness with regard to errors, which are to be expected in any real-world working environment at some point, as well as by its excellent achievable resolution. The actual implementation of the pattern on the road surface modules can be carried out, for example, using paint applied before or after the road surface modules are laid, provided that the pattern is to be read optically using camera units.

[0031] According to a further aspect, the present invention relates to a system, in particular a packaging machine system, comprising a plurality of stations for handling objects and a system according to the invention of the type just described. In this system, at least some of the stations can be configured to receive objects from or transfer them to the at least one transport vehicle.

[0032] According to yet another aspect, the present invention relates to a method for determining the position of a transport vehicle in such a system, comprising, upon commissioning of the transport vehicle, determining on which of the driving surface modules the transport vehicle is currently located, and during ferry operation of the transport vehicle, detecting at least the drivable surface in order to determine the position of the driverless transport vehicle in the coordinate system of the currently traversed driving surface module.It is of course possible to determine which of the track modules the transport vehicle is currently located on at later times during the operation of the transport vehicle, for example periodically to ensure correct position detection, or in the event of a malfunction or an unplanned position determination, in order to enable a reset of the position determination of the corresponding transport vehicle in such a case.

[0033] As mentioned above, it may also be possible to determine the orientation of the transport vehicle in the coordinate system of the currently traversed surface module, whereby, for example, an arbitrarily definable angle with respect to an axis of the two-dimensional pattern of the driving surface modules can be used as an additional coordinate.

[0034] Furthermore, the method according to the invention can, in the manner already indicated above in 221349PDE / FEHHslo 10, include assigning the position and, if necessary, orientation of the transport vehicle in the coordinate system of the currently traversed area module to a position and, if necessary, orientation in a coordinate system of the plant.

[0035] Further features and advantages of the present invention will become even clearer from the following description of an embodiment thereof, when viewed together with the accompanying figures. These show in detail:

[0036] Figure 1: a schematic top view of a system according to the invention, in which a system according to the invention is used; and

[0037] Figures 2a to 2c: different representations of the driving surface modules used in the system from Figure 2.

[0038] Figure 1 shows, in a purely schematic top view, a system according to the invention, which is generally designated by reference numeral 10, and which comprises an indicated system 100 according to the invention and a plurality of stations M1 - M4 for handling objects. The system 10 can, for example, be a packaging machine system, wherein at least some of the stations M1 - M4 can be configured to receive objects from or transfer them to driverless transport vehicles 12.

[0039] The transport vehicles 12, of which only one is shown in Figure 1 for clarity, form part of the system 100 according to the invention and are generally designed to transport objects between stations M1-M4 of the system or other transfer points. For this purpose, they are equipped with suitable components that enable driverless operation, such as a vehicle control unit 12b for controlling the vehicle's functions, a communication unit (not shown here) for establishing a wireless communication link with a central control unit or monitoring station 14, a drive system controlled by the vehicle control unit 12b, and sensor and safety systems for preventing collisions and similar incidents with stationary objects, people, or other vehicles.The central control unit 14 of the system 10 is designed to coordinate the operation of the transport vehicles 12 by means of work instructions and similar, and, depending on the design of the system 10 and the intended work processes, also the operation of stations M1 - M4.

[0040] In this system, the transport vehicles 12 move on a drivable surface 16, which also forms part of the system according to the invention and which is composed of a plurality of driving surface modules 16a. These modules are shown, for example, in a more detailed view in Figure 2a and are provided on their upper surface with an identical two-dimensional pattern, which can be printed on the upper surface of the driving surface modules 16a, for example, using a suitable dye. It should be noted at this point, and with reference to Figures 2a to 2c explained below, that different dimensions of driving surface modules 16a to 16c can be provided, which, however, have identical two-dimensional patterns.

[0041] In order to determine their own position within the system 10, which must be known with high precision in order to process work and transport orders appropriately, the transport vehicles 12 are each equipped with camera units 12a. These units are arranged such that they each capture a predetermined section of the drivable surface 16 and serve as exemplary embodiments of detection units according to the present invention. This predetermined section of the surface is accordingly in a fixed spatial relationship to the body of the respective transport vehicle 12. By suitable image evaluation of the two-dimensional pattern provided on the upper surface of the corresponding driving surface module 16a, both the current position 221349PDE / FEHHslo 12 and an angle in a local reference system of the currently traversed driving surface module 16a can be derived.The necessary image recognition and processing can be carried out, for example, by the vehicle control unit or another control unit coupled to it, using algorithms that are known per se.

[0042] In this context, it should also be noted that transitions from one of the road surface modules 16a to an adjacent one can also be recognized and treated accordingly within the framework of the recording of the two-dimensional pattern, so that a transition to the local coordinate system of the now traversed road surface module 16a is subsequently carried out.

[0043] Furthermore, it should be noted that the control unit of the transport vehicle 12, which is responsible for determining its position, also has access to a map of the system 10 stored in a memory unit. Therefore, if the position of the transport vehicle 12 in the local coordinate system of the currently traversed roadway module 16a and the identity of the roadway module 16a in question are known, a corresponding position in a global coordinate system of the system 10 can be derived. A similar process applies to the orientation of the transport vehicle 12 on the corresponding roadway module 16a, whereby, for example, two Cartesian coordinates and one angular coordinate with respect to one of the coordinate axes can be used to describe the position and orientation of the transport vehicle 12.

[0044] For this purpose, it may be necessary at certain times to determine on which of the track modules the transport vehicle 12 is currently located, for example, during commissioning when its own position within the plant 10 is initially unknown. Various approaches are conceivable for this purpose; for example, the transport vehicles 12 could be equipped with a localization unit that allows a low-resolution position determination within the plant 10. While this would not initially provide sufficient precision to determine the vehicle's own position for carrying out work orders, it would in any case allow the determination of the track module 16a currently being used.In alternative variants, it would also be conceivable, for example, to roughly determine the position of the transport vehicle 12 or to determine the currently driven-on driving surface module 16a by means of an external camera system 18 shown schematically here as an example of an external detection unit of the system 100 according to the invention and to supply corresponding data to the transport vehicle 12.

[0045] Finally, with reference to Figures 2a to 2c, the basic design and possible arrangements of the driving surface modules 16a from Figure 1, as well as further driving surface modules 16b and 16c with differing dimensions, will be explained. It will become clear that, in principle, any arbitrarily shaped drivable surface can be covered by means of such driving surface modules using a suitably chosen set of geometries. Driving surface modules with a shape other than a rectangle are, of course, also conceivable. Furthermore, it can be seen that the two-dimensional patterns used in the present example are in the form of a binary-coded, continuous code in two dimensions, that is, they are essentially formed by two barcode-like patterns intersecting each other at an angle, from which unique X and Y coordinates can be derived.Here, the required resolution for determining the position of a transport vehicle 12 in relation to the size of the recorded area of ​​the road surface 16 must be considered, and it must be ensured that the road surface modules 16a to 16c used provide sufficient information content with regard to their size and pattern to allow the determination of the current position of the corresponding transport vehicle 12 in the local coordinate system of the respective road surface module at any given time.

Claims

221349PDE / FEHHslo 14 Claims 1. System (100) for transporting objects in a plant (10) with a plurality of stations (M1 - M4), in particular a packaging machine plant, comprising: - at least one driverless transport vehicle (12) equipped to transport objects between the stations (M1 - M4); - a central control unit (14) which is communicatively coupled with the at least one transport vehicle (12) and the stations (M1 - M4) and is designed to coordinate the operation of the at least one transport vehicle (12) and, if applicable, the stations (M1 - M4); - a drivable surface (16) on which the at least one driverless transport vehicle (12) moves, and - at least one detection unit (12a) which is configured to detect at least the drivable surface (16) in order to determine a position of the at least one driverless transport vehicle (12) within the system (10), wherein the drivable surface (16) comprises a plurality of driving surface modules (16a) which are provided on their upper surface with an identical two-dimensional pattern which, when detecting a surface section with predetermined dimensions thereof, enables a unique determination of a position in a coordinate system of the driving surface module (16a).

2. System (100) according to claim 1, wherein the two-dimensional pattern, when detected, further enables the determination of an angle to the coordinate system of the driving surface module (16a).

3. System (100) according to claim 1 or 2, wherein the drivable surface comprises a plurality of driving surface modules (16a - 16c) with different dimensions, wherein 221349PDE / FEHHslo 15 Driving surface modules (16a - 16c) with the same dimensions exhibit identical two-dimensional patterns.

4. System (100) according to one of the preceding claims, wherein each of the transport vehicles (12) is assigned one of the detection units (12a) which is operationally coupled to a control unit (12b) of the transport vehicle (12) which is configured to determine the current position on the corresponding driving surface module (16a) on the basis of the area section of the driving surface (16) detected by the detection unit (12a).

5. System (100) according to claim 4, wherein the control unit (12b) of the transport vehicle (12) further has access to a map of the system (10) stored in a memory unit, which enables the coordinate systems of the driving surface modules (16a) to be assigned to a coordinate system of the system (10).

6. System (100) according to claim 4 or 5, wherein the control unit (12b) of the transport vehicle (12) is further configured to determine a transition of the transport vehicle (12) from one driving surface module (16a) to another during a movement thereof.

7. System (100) according to one of claims 4 to 6, wherein the at least one transport vehicle (12) further comprises a localization unit which is able to determine on which of the driving surface modules (16a) the transport vehicle is currently located, in particular when the transport vehicle is put into operation.

8. System (100) according to one of claims 4 to 7, wherein the detection unit (12a) associated with the at least one transport vehicle (12) is formed by a camera unit, a magnetic sensor unit or a capacitive sensor unit. 221349PDE / FEHHslo 16 9. System (100) according to one of the preceding claims, wherein at least one of the detection units (18) is installed outside the transport vehicles (12) in the system and is configured to detect at least one of the driving surface modules (16a) and transport vehicles (12) located thereon, wherein this detection unit is preferably designed as a camera unit 10. System (100) according to any one of the preceding claims, wherein the two-dimensional pattern is a binary-coded continuous code in two dimensions.

11. Plant (10), in particular packaging machine plant, comprising a plurality of stations (M1 - M4) for handling objects and a system (100) according to one of the preceding claims.

12. System (10) according to claim 11, wherein at least some of the stations (M1 - M4) are equipped to receive objects from or transfer them to the at least one transport vehicle (12).

13. Method for determining the position of a transport vehicle (12) in a plant (10) according to one of claims 11 and 12, comprising: - when the transport vehicle (12) is put into operation, determine on which of the driving surface modules (16a) the transport vehicle (12) is currently located, and - during a ferry operation of the transport vehicle (12), recording of at least the drivable surface (16) in order to determine the position of the driverless transport vehicle (12) in the coordinate system of the currently traversed road surface module (16a).

14. Method according to the preceding claim, 221349PDE / FEHHslo 17 further comprising determining an orientation of the transport vehicle (12) in the coordinate system of the currently traversed area module (16a).

15. Method according to one of claims 13 and 14, further comprising assigning the position and, if applicable, orientation of the transport vehicle (12) in the coordinate system of the currently traversed area module (16a) to a position and, if applicable, orientation in a coordinate system of the system (10).

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