Multi-system synchronization method, device and storage medium applied to 3D printing

Abstract

Embodiments of the present specification provide a multi-system synchronization method, device and storage medium applied to 3D printing, the multi-system includes a printer and an extruder, the method comprises: collecting movement information of the printer; determining extrusion value data of the extruder according to the movement information; creating a functional relationship between a printing point of the printer and a material extrusion control node of the extruder according to the movement information and the extrusion value data; and controlling the printer and the extruder to run synchronously according to the functional relationship. The technical scheme provided in the present application is used to solve the problem of the prior art that the printer and the extruder are not synchronized and the amount of consumables is large.

Description

TECHNICAL FIELD

[0001] The present document relates to the field of 3D printing, and in particular to a multi-system synchronization method, device and storage medium applied to 3D printing. BACKGROUND

[0002] 3D printing technology is a process technology that constructs a three-dimensional entity through layer-by-layer deposition of materials based on a three-dimensional model of a part. Because of its fast forming speed, low cost, and the ability to construct complex structures, it has been widely used in the fields of electronics, medicine, construction, and aerospace.

[0003] The conventional printing mode is based on the arbitrary movement of the printer in three directions (three axes) and the pre-setting of a support body.

[0004] However, when the printer moves in three axes, the printer and the extruder cannot be integrated, so the printer and the extruder need to move simultaneously. In addition, when the support structure and the formed object are separated, some consumables are attached to the support body, resulting in waste of consumables. SUMMARY

[0005] In view of the above analysis, the present application aims to provide a multi-system synchronization method, device and storage medium applied to 3D printing, for solving at least one of the above technical problems.

[0006] In a first aspect, one or more embodiments of the present specification provide a multi-system synchronization method applied to 3D printing, comprising:

[0007] acquiring movement information of the printer;

[0008] determining extrusion value data of the extruder according to the movement information;

[0009] creating a functional relationship between a printing point of the printer and a material extrusion control node of the extruder according to the movement information and the extrusion value data;

[0010] controlling the printer and the extruder to run synchronously according to the functional relationship.

[0011] Further, the printer is arranged on a mechanical arm.

[0012] The acquisition of the movement information of the printer comprises:

[0013] acquiring a movement trajectory of the mechanical arm.

[0014] Further, the movement information is from G code of the mechanical arm.

[0015] Further, the determining the extrusion value data of the extruder according to the movement information comprises:

[0016] determining a movement length of the printer according to the movement information;

[0017] determining a volume corresponding to the movement length;

[0018] determining the extrusion value data according to the volume corresponding to the movement length.

[0019] Further, the controlling the printer and the extruder to run synchronously according to the function relationship comprises:

[0020] detecting a current printing point of the printer;

[0021] determining a current extrusion node of the extruder according to the function relationship and the current printing point;

[0022] sending an instruction to the printer and the extruder simultaneously according to the current printing point and the current extrusion node.

[0023] In a second aspect, one or more embodiments of the present specification provide a multi-system synchronization device applied to 3D printing, comprising: a collection module, a data processing module and a control module;

[0024] The collection module is configured to collect movement information of the printer;

[0025] The data processing module is configured to determine extrusion value data of the extruder according to the movement information, and create a function relationship between a printing point of the printer and a material extrusion control node of the extruder according to the movement information and the extrusion value data;

[0026] The control module is configured to control the printer and the extruder to run synchronously according to the function relationship.

[0027] Further, the collection module is configured to collect a movement trajectory of the mechanical arm.

[0028] Further, the data processing module is configured to determine a movement length of the printer according to the movement information, determine a volume corresponding to the movement length, and determine the extrusion value data according to the volume corresponding to the movement length.

[0029] Further, the control module is configured to detect a current printing point of the printer;

[0030] determine a current extrusion node of the extruder according to the function relationship and the current printing point;

[0031] According to the current printing point and the current extrusion node, instructions are sent to the printer and the extruder simultaneously.

[0032] In a third aspect, one or more embodiments of the present specification provide a storage medium comprising:

[0033] For storing computer executable instructions, the computer executable instructions, when executed, implement the method of the first aspect.

[0034] Compared with the prior art, the present application can at least achieve the following technical effects:

[0035] The points passed by the 3D printer nozzle are printing points, and the number of materials extruded by the extruder is the extrusion amount (extrusion value data). The printing points are obtained based on the movement information of the printer, and then the extrusion amount of each printing point is obtained, so as to realize the establishment of the quantity relationship and data contact between the printer and the extruder, and finally realize the synchronous control of the printer and the extruder based on the quantity relationship and data contact. In addition, the synchronous control makes the 3D printing model more accurate, so that for some load curved surface space structures, support structures do not need to be set. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the one or more embodiments of the present specification or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present specification, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0037] Figure 1 A flow chart of a multi-system synchronization method applied to 3D printing is provided for one or more embodiments of the present specification.

[0038] Figure 2 A mapping relationship between a printing point and a material extrusion control node is provided for one embodiment of the present specification.

[0039] Figure 3 A structure diagram of a Twist part is provided for one embodiment of the present specification. DETAILED DESCRIPTION

[0040] In order for those skilled in the art to better understand the technical solutions in the one or more embodiments of the present specification, the technical solutions in the one or more embodiments of the present specification will be clearly and completely described in the following with reference to the drawings in the one or more embodiments of the present specification. Obviously, the described embodiments are only a part of the embodiments of the present specification, rather than all the embodiments. Based on the one or more embodiments of the present specification, all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present document.

[0041] The conventional three-axis printing equipment widely used at present can only deposit materials along a single direction for printing because of its low degree of freedom, which leads to the need to add support structures to continue printing when printing parts with complex structures, such as parts with overhanging structures. The existence of support structures increases the printing time and wastes printing materials, and manual removal is required for post-processing after printing, which may further cause the surface quality of the printed parts to decrease.

[0042] While the separation of the printer and the extruder can solve the problem of low degree of freedom to some extent, it cannot control the synchronous operation of the printer and the extruder, and still causes defects in the model.

[0043] Based on the above technical scenarios, the present application provides a multi-system synchronization method applied to 3D printing, comprising the following steps:

[0044] Step 1, collecting the movement information of the printer.

[0045] In the embodiments of the present application, the movement information is the trajectory of the printer when it is running. The 3D printer will set a certain route, i.e. the aforementioned trajectory, before printing.

[0046] Preferably, in order to improve the printing degree of freedom, the printer is arranged on a mechanical arm. The mechanical arm can improve the degree of freedom to 4-6 or even more. At this time, the movement information of the printer comes from the G code of the mechanical arm.

[0047] Step 2, determining the extrusion value data of the extruder according to the movement information.

[0048] In the embodiments of the present application, the movement length of the printer is determined according to the movement information. The volume corresponding to the movement length is determined, assuming that the nozzle of the 3D printer is a fixed-size circle, and the workpiece has multiple stereoscopic images obtained by the space change of the "nozzle". This space change is the movement length. Therefore, the volume of the workpiece can be obtained based on the movement length. The extrusion value is determined according to the volume corresponding to the movement length. The density of the consumables can be known in advance, so the extrusion value can be obtained based on the volume corresponding to the movement length.

[0049] Taking the arc-shaped workpiece as an example, according to the movement information, the current position pi of the mechanical arm can be obtained, and the last recorded position pi-1 is subtracted, so that the arc length li=pi-pi-1 walked by the end of the mechanical arm in the time t can be obtained. Adding li to the total cumulative arc length l walked before, ls=li+l is the total arc length walked by the mechanical arm from the start of movement to this time. According to the total arc length and the nozzle size, the volume corresponding to the total arc length can be obtained. Finally, according to the density of the consumables and the volume corresponding to the total arc length, the extrusion value data is determined.

[0050] Step 3, according to the movement information and the extrusion value data, a function relationship between the printing point of the printer and the material extrusion control node of the extruder is created.

[0051] In the embodiment of the present application, the movement trajectory in the time Δt is the printing point, and the extrusion value in the corresponding time Δt is the material extrusion control node, so that the function relationship between the two can be constructed, as shown in the following formula. Figure 2

[0052] Step 4, according to the function relationship, control the printer and the extruder to run synchronously.

[0053] In the embodiment of the present application, the current printing point of the printer is detected; according to the function relationship and the current printing point, the current extrusion node of the extruder is determined; according to the current printing point and the current extrusion node, instructions are sent to the printer and the extruder at the same time.

[0054] For example, the communication between the mechanical arm system and the material extrusion system is realized using ROS under the ubuntu system. First, two ROS nodes, Robot_control node and Marlin_control node, are initialized, where Robot_control represents the control node of the mechanical arm, and Marlin_control represents the control node of the material extrusion system. The topic function in ROS is used to transmit topic messages between the two nodes, so as to realize the communication between the two systems. Among them, the mechanical arm node Robot_control publishes messages as a Publisher, and the material extrusion node receives messages as a Subscriber. The message msg:gcode published between the two nodes is a custom G code message, which includes the length of the material feeding required by the material extrusion system.

[0055] In order to illustrate the feasibility of the above embodiment, the present application gives the following example, according to the above method, the workpiece as shown in the following formula is processed. Figure 3

[0056] Figure 3 ​​The workpiece is a curved layer printed part, which is a Twist model with a series of curved layer slices, and the height of the model is about 115 mm. The slicing method used for the part is the so-called ellipsoid slicing method, which means that each layer is part of an ellipsoid. Therefore, during the printing process, the end printing platform will always rotate to adjust the rotation angle, which can directly show the flexibility of the multi-axis printing of the application compared with the traditional three-axis printing. The whole process takes about 5.6 hours, and the consumption of consumables is 7.8g. The consumption of consumables in the prior art is usually greater than 14g.

[0057] The embodiment of the application provides a multi-system synchronization device applied to 3D printing, comprising: a collection module, a data processing module and a control module.

[0058] The collection module is used for collecting movement information of the printer.

[0059] The data processing module is used for determining extrusion value data of the extruder according to the movement information; and creating a functional relationship between a printing point of the printer and a material extrusion control node of the extruder according to the movement information and the extrusion value data.

[0060] The control module is used for controlling the printer and the extruder to run synchronously according to the functional relationship.

[0061] In the embodiment of the application, the collection module is used for collecting a movement trajectory of the mechanical arm.

[0062] In the embodiment of the application, the data processing module is used for determining a movement length of the printer according to the movement information; determining a volume corresponding to the movement length; and determining the extrusion value data according to the volume corresponding to the movement length.

[0063] In the embodiment of the application, the control module is used for detecting a current printing point of the printer.

[0064] According to the functional relationship and the current printing point, a current extrusion node of the extruder is determined.

[0065] According to the current printing point and the current extrusion node, instructions are sent to the printer and the extruder at the same time.

[0066] The embodiment of the application provides a storage medium, comprising:

[0067] The computer executable instructions are used for storing computer executable instructions, and the computer executable instructions are used for realizing the method in the above-mentioned embodiment when being executed.

[0068] The above described embodiments of the present description have been described. Other embodiments are within the scope of the following claims. In some cases, the actions or steps recited in the claims can be performed in a different order and still achieve desirable results. Additionally, the processes depicted in the figures do not necessarily require the particular order shown, or sequential order, to achieve the desired results. In certain implementations, multitasking and parallel processing can be advantageous.

[0069] In the 1930s, it was clear to distinguish whether an improvement in a technology was in hardware (e.g., improvement in circuit structure of diodes, transistors, switches, etc.) or in software (e.g., improvement in method flow). However, as technology has evolved, many improvements in method flow today can be considered as direct improvements in hardware circuit structure. Designers almost always obtain the corresponding hardware circuit structure by programming the improved method flow into the hardware circuit. Therefore, it cannot be said that an improvement in a method flow cannot be implemented by a hardware entity module. For example, a programmable logic device (PLD) (e.g., a field programmable gate array (FPGA)) is an integrated circuit whose logic function is determined by user programming of the device. A digital system is "integrated" on a PLD by the designer programming it, rather than by asking a chip manufacturer to design and fabricate a custom integrated circuit chip. Moreover, instead of manually fabricating an integrated circuit chip, this programming is now mostly implemented by "logic compiler" software, which is similar to software compilers used in program development, and the original code to be compiled is written in a specific programming language, called a hardware description language (HDL), of which there are many, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, RHDL (Ruby Hardware Description Language), etc., the most commonly used being VHDL (Very-High-Speed Integrated Circuit Hardware Description Language) and Verilog. It should be clear to those skilled in the art that, by simply logically programming a method flow in one of the above hardware description languages and programming it into an integrated circuit, a hardware circuit implementing the logical method flow can be easily obtained.

[0070] The controller can be implemented in any suitable way, for example, the controller can take the form of a microprocessor or processor and a computer readable medium storing computer readable program code, e.g. software or firmware, executable by the (micro)processor, logic gates, switches, an application specific integrated circuit (ASIC), a programmable logic controller and an embedded microcontroller, examples of which include but are not limited to the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicone Labs C8051F320, the memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art will also know that, in addition to being implemented in pure computer readable program code form, the controller can perfectly well be implemented to perform the same functions using logic gates, switches, an application specific integrated circuit, a programmable logic controller and an embedded microcontroller, etc. by means of a logical programming of the method steps. Such a controller can thus be considered as a hardware component, while the means comprised therein for performing the various functions can also be considered as structures within the hardware component. Alternatively, the means for performing the various functions can even be considered as both a software module implementing the method and a structure within the hardware component.

[0071] The systems, apparatuses, modules or units illustrated by the above embodiments can be specifically implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, the computer can be, for example, a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or a combination of any of these devices.

[0072] For the sake of description, the above apparatuses are described in functional division and are described respectively. Of course, the functions of the units can be implemented in the same or multiple software and / or hardware when implementing the embodiments of the present specification.

[0073] Those skilled in the art will understand that one or more embodiments of the present specification can be provided as a method, a system or a computer program product. Therefore, one or more embodiments of the present specification can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present specification can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0074] The specification is presented with reference to flow diagrams and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the specification. It will be understood that each block of the flow diagrams and / or block diagrams, and combinations of blocks in the flow diagrams and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general purpose computer, special purpose computer, embedded processing element or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flow diagrams and / or block diagrams block or blocks. Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in

[0075] The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in

[0076] The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in Figure 1 The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in The flow diagrams and / or block diagrams in the specification can present a method, apparatus or computer program product according to embodiments of the specification. Although the flow diagrams and / or block diagrams can present a method, apparatus or computer program product in a particular, it is understood that the method, apparatus and computer program product can include one or more additional steps, operations, or functions, and the method, apparatus and computer program product can include one or more other steps, operations, functions or combinations of steps, operations, or functions in

[0077] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0078] The memory can include non-persistent memory and / or other volatile memory, representing a random access memory (RAM) comprising a computer readable medium for storing information (e.g., computer readable instructions, data structures, program modules or other data such as a database). The memory is an example of computer readable storage media.

[0079] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0080] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover non-exclusive inclusion, such that processes, methods, articles or devices that include a series of elements not only include those elements, but also include other elements not explicitly listed or inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or device that includes the element.

[0081] One or more embodiments of the present specification can be described in the general context of computer-executable instructions being executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, and the like that perform particular tasks or implement particular abstract data types. One or more embodiments of the present specification can also be practiced in a distributed computing environment, in which tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in both local and remote computer storage media, including storage devices.

[0082] Each embodiment in the present specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment focuses on the difference from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and the relevant parts can be referred to the part of the method embodiment.

[0083] The above merely provides the example of the present document and is not intended to limit the present document. For those skilled in the art, the present document can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present document shall be included in the scope of claims of the present document.

Claims

1. A multi-system synchronization method for 3D printing, characterized in that, The multi-system includes a printer and an extruder, and the method includes: Collect the movement information of the printer; Based on the movement information, the extrusion value data of the extruder is determined; Based on the movement information and the extrusion value data, a functional relationship is created between the printing point of the printer and the material extrusion control node of the extruder; Based on the aforementioned functional relationship, the printer and the extruder are controlled to operate synchronously. The step of controlling the printer and the extruder to operate synchronously according to the functional relationship includes: Detect the current print point of the printer; Based on the functional relationship and the current printing point, determine the current extrusion node of the extruder; Instructions are sent simultaneously to the printer and the extruder based on the current print point and the current extrusion node.

2. The method according to claim 1, characterized in that, The printer is mounted on a robotic arm; The collection of the printer's movement information includes: The movement trajectory of the robotic arm is collected.

3. The method according to claim 2, characterized in that, The movement information comes from the G-code of the robotic arm.

4. The method according to claim 1, characterized in that, Determining the extrusion value data of the extruder based on the movement information includes: Based on the movement information, determine the movement length of the printer; Determine the volume corresponding to the moving length; The extrusion value data is determined based on the volume corresponding to the moving length.

5. A multi-system synchronization device for 3D printing, as described in claim 1, characterized in that, include: Acquisition module, data processing module, and control module; The acquisition module is used to acquire the movement information of the printer; The data processing module is used to determine the extrusion value data of the extruder based on the movement information; and to create a functional relationship between the printing point of the printer and the material extrusion control node of the extruder based on the movement information and the extrusion value data. The control module is used to control the printer and the extruder to operate synchronously according to the functional relationship, including: Detect the current print point of the printer; Based on the functional relationship and the current printing point, determine the current extrusion node of the extruder; Instructions are sent simultaneously to the printer and the extruder based on the current print point and the current extrusion node.

6. The apparatus according to claim 5, characterized in that, The printer is mounted on a robotic arm; The acquisition module is used to acquire the movement trajectory of the robotic arm.

7. The apparatus according to claim 5, characterized in that, The data processing module is used to determine the movement length of the printer based on the movement information; determine the volume corresponding to the movement length; and determine the extrusion value data based on the volume corresponding to the movement length.

8. The apparatus according to claim 5, characterized in that, The control module is used to detect the current print point of the printer; Based on the functional relationship and the current printing point, determine the current extrusion node of the extruder; Instructions are sent simultaneously to the printer and the extruder based on the current print point and the current extrusion node.

9. A storage medium, characterized in that, include: Used to store computer-executable instructions, which, when executed, implement the method according to any one of claims 1-4.

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