A vehicle assembly tightening method, system and aid

Abstract

The application provides a vehicle assembly tightening method, system and auxiliary device, and relates to the technical field of automobiles.The method comprises the following steps: step 1: obtaining three-dimensional data and coordinate information of a vehicle frame component and a to-be-assembled part preassembled on the vehicle frame component; step 2: inputting the obtained three-dimensional data and coordinate information of the vehicle frame component and the to-be-assembled part into a preset database to obtain a torque assembly list of the to-be-assembled part; step 3: when the to-be-assembled part meets a first preset condition, calling the torque assembly list of the to-be-assembled part; step 4: sending the torque assembly list to a display interface of a tightening unit; and step 5: based on a user operation instruction, fixing the to-be-assembled part on the vehicle frame component according to the torque assembly list.The application overcomes the technical problems of slow production progress and low production efficiency caused by misoperation after part change in the product trial development process.

Description

Technical Field

[0001] The present application relates to the field of automotive technology, and in particular to a vehicle assembly tightening method, system, and auxiliary device. Background Art

[0002] Currently, during the product trial development process, due to the short production cycle and product version iteration, technical requirements and content need to be constantly updated. At this stage, the method used for tightening standard parts with torque requirements during assembly is for technicians to first prepare a list of tightening parts with torque requirements. Then, after importing the list of tightening parts into the system, a barcoded torque file is generated and sent to the site. In addition, the tightening parts are installed on the vehicle frame based on the workers' experience, which can easily lead to misplacement. At the same time, each tightening of a tightening part during the operation requires scanning the code once to obtain the torque information for assembly. This operation requires reprocessing and changing the tightening parts list when there is a part change. Due to the large amount of manual processing required and the low operational efficiency, operational errors are prone to occur, affecting production progress and reducing production efficiency. This cannot meet the high technical, quality, and operational requirements for the mixed production of multiple models of trial prototypes. Summary of the Invention

[0003] The purpose of this application is to provide a vehicle assembly tightening method, system and auxiliary device to overcome the technical problem of misoperation caused by part changes during product trial development, different vehicle models, and version iterations, which affects production progress. The specific solution is as follows:

[0004] A vehicle assembly tightening method, the method comprising the following steps:

[0005] Step 1: Acquire three-dimensional data and coordinate information of a vehicle frame component and parts to be assembled pre-installed on the vehicle frame component;

[0006] Step 2: Input the acquired 3D data and coordinate information of the frame components and parts to be assembled into a preset database to obtain a torque assembly list of the parts to be assembled;

[0007] Step 3: In response to the part to be assembled meeting the first preset condition, calling the torque assembly list of the part to be assembled;

[0008] Step 4: Sending the torque assembly list to the display interface of the tightening unit;

[0009] Step 5: Based on the user's operating instructions and in accordance with the torque assembly list, the parts to be assembled are fixed to the frame components.

[0010] In some specific embodiments, step 2 includes:

[0011] acquire three-dimensional data of the frame component and the part to be assembled;

[0012] search a preset database to find whether there is a three-dimensional model matching the frame component and the part to be assembled;

[0013] if matched, acquire a torque assembly list of the part to be assembled based on coordinate information of the frame component and the part to be assembled.

[0014] In some embodiments, the acquiring of the torque assembly list of the part to be assembled based on the coordinate information of the frame component and the part to be assembled specifically includes:

[0015] acquiring first position information of the frame component based on a positioning structure;

[0016] determining second position information of the part to be assembled based on three-dimensional data of the frame component and the first position information;

[0017] sending the first position information and the second position information to the preset database to acquire the torque assembly list of the part to be assembled.

[0018] In some embodiments, the torque assembly list of the part to be assembled is called in response to the part to be assembled satisfying a first preset condition, and the calling specifically includes:

[0019] acquiring third position information of a tightening unit in an assembly process;

[0020] The first preset condition includes:

[0021] the torque assembly list of the part to be assembled is called when the third position information matches the second position information of the part to be assembled and a bolt stress torque of the part to be assembled is greater than a preset torque value.

[0022] In some embodiments, an image display interface is generated based on the acquired three-dimensional data and coordinate information of the frame component and the part to be assembled;

[0023] an assembly state of the part to be assembled is acquired based on the image display interface.

[0024] In some embodiments, the method further includes the following steps:

[0025] a tightening force of the tightening unit is acquired in real time in a tightening process;

[0026] a first control instruction and a second control instruction are output when the tightening force of the tightening unit reaches a design value of the torque assembly list;

[0027] Based on the first control instruction, shutting down the tightening unit; and

[0028] Based on the second control instruction, prompt information is generated on the image display interface.

[0029] A vehicle assembly auxiliary device, used to implement the vehicle assembly tightening method, the device comprising:

[0030] A positioning frame, wherein a plurality of visual acquisition units are evenly arranged at the top and bottom of the positioning frame;

[0031] A visual acquisition unit, configured to acquire image information and position information; wherein the image information includes image information of the frame components and the parts to be assembled; and the position information includes position information of the frame components, the parts to be assembled, and the tightening unit;

[0032] A tightening unit, used to fix the parts to be assembled on the frame components;

[0033] Positioning calibration unit, used to locate the initial position information of the tightening unit;

[0034] The main control unit is used to obtain the three-dimensional data and position information sent by the visual acquisition unit in real time and generate an image display interface.

[0035] In some specific embodiments, the tightening unit includes: an electric tightening gun and a tightening member connected to the front end of the electric tightening gun; wherein, a display screen is provided at the upper end of the electric tightening gun; and a posture sensor is also provided inside the electric tightening gun.

[0036] A vehicle assembly tightening system, comprising:

[0037] A first acquisition module is configured to acquire three-dimensional data of a frame component and a part to be assembled pre-installed on the frame component;

[0038] A second acquisition module is configured to input the acquired three-dimensional data and coordinate information of the frame components and the parts to be assembled into a preset database to obtain a torque assembly list of the parts to be assembled;

[0039] a calling module configured to call a moment assembly list of the part to be assembled model in response to the part to be assembled meeting a first preset condition;

[0040] a sending module configured to send the torque assembly list to a display interface of the tightening unit;

[0041] The control module is configured to fix the parts to be assembled on the frame component according to the torque assembly list based on the user's operation instructions.

[0042] An electronic device comprises: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention provides a vehicle assembly tightening method, system and auxiliary device, which obtain the torque assembly list of the parts to be assembled by obtaining the three-dimensional data and coordinate information of the frame component and the parts to be assembled pre-installed on the frame component; when the parts to be assembled meet the first preset condition, the torque assembly list of the model of the parts to be assembled is called; based on the torque assembly list, the torque information of the parts to be assembled is obtained; the torque information is read through the display interface of the tightening unit, and the parts to be assembled are fixed on the frame component; the advantage of this design compared to the existing technology is that it avoids the technical problems of slow production progress and low production efficiency caused by erroneous operations after parts changes during the iteration process of different models and versions. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flow chart of the tightening method for vehicle assembly;

[0046] Figure 2 A schematic diagram of the overall structure of the vehicle assembly auxiliary device;

[0047] Figure 3 This is a schematic diagram of the installation position of the positioning bracket inside the positioning frame;

[0048] Figure 4 It is a structural diagram of the tightening unit;

[0049] Figure 5 It is a structural diagram of the positioning calibration unit;

[0050] Figure 6 This is a schematic diagram of the installation of the parts to be assembled on the frame components. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of this application clearer, the following Figure 1-6 This application is further described in detail. Obviously, the embodiments described are only a part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0052] It should be understood that although the terms first, second, third, etc. may be used to describe in the embodiments of the present application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, without departing from the scope of the embodiments of the present application, the first may also be referred to as the second, and similarly, the second may also be referred to as the first.

[0053] like Figure 1 As shown, the present application provides a vehicle assembly tightening method, the method comprising the following steps:

[0054] Step 1: Acquire three-dimensional data and coordinate information of a vehicle frame component and parts to be assembled pre-installed on the vehicle frame component;

[0055] Step 2: Input the acquired 3D data and coordinate information of the frame components and parts to be assembled into a preset database to obtain a torque assembly list of the parts to be assembled;

[0056] Step 3: In response to the part to be assembled meeting the first preset condition, calling the torque assembly list of the part to be assembled;

[0057] Step 4: Sending the torque assembly list to the display interface of the tightening unit;

[0058] Step 5: Based on the user's operating instructions and in accordance with the torque assembly list, the parts to be assembled are fixed to the frame components.

[0059] It can be understood that the present application obtains the torque assembly list of the parts to be assembled through the three-dimensional data and coordinate information of the frame components and the parts to be assembled, and in response to the parts to be assembled meeting the first preset condition, calls the torque assembly list of the parts to be assembled model, and at the same time reads the torque information through the display interface of the tightening unit to fix the parts to be assembled on the frame components; this design avoids the erroneous operation caused by the need to manually change the tightening parts list after the parts are changed during the iteration of different models and versions in the prior art. However, the present application, by reviewing the data and orientation of the product, can call the torque information of the parts to be assembled only when the preset conditions are met, thereby improving the assembly accuracy, avoiding operational errors, and improving production progress and production efficiency.

[0060] Optionally, the step of inputting the acquired three-dimensional data and coordinate information of the frame components and the parts to be assembled into a preset database to obtain a moment assembly list of the parts to be assembled specifically includes:

[0061] Acquiring three-dimensional data of the frame component and the parts to be assembled;

[0062] Traversing a preset database to search for a three-dimensional model that matches the frame component and the parts to be assembled;

[0063] If matched, torque assembly list of the part to be assembled is obtained based on coordinate information of the frame component and the part to be assembled.

[0064] In the embodiment, 3D data of the frame component and the part to be assembled is obtained, and the 3D data is sent to a preset database for searching and matching. According to the matching result, it is determined whether to obtain the torque assembly list of the part to be assembled based on the coordinate information of the frame component and the part to be assembled. It can be understood that in this way, it can be firstly determined whether the part to be assembled is matched with the frame component. If the matched part to be assembled and the frame component are not found in the preset database, it indicates that the part to be assembled is not a part on the frame component, and the part to be assembled needs to be placed in a to-be-processed area for subsequent processing. If the matching is successful, the torque assembly list of the part to be assembled is obtained based on the coordinate information of the frame component and the part to be assembled.

[0065] Optionally, the obtaining of the torque assembly list of the part to be assembled based on the coordinate information of the frame component and the part to be assembled specifically comprises:

[0066] obtaining first position information of the frame component;

[0067] obtaining second position information of the part to be assembled;

[0068] sending the first position information and the second position information to a preset database to obtain the torque assembly list of the part to be assembled.

[0069] In the embodiment, the first position information of the frame component and the second position information of the part to be assembled are sent to the preset database for information searching and matching. If the matching result is the same, it indicates that the installation position of the part to be assembled and the frame component is correct, and then the torque assembly list of the part to be assembled is obtained. The advantage of the design is that through comparison of the position information, it can assist the on-site assembly personnel to determine whether the installation position of the part to be assembled is correct, instead of determining the assembly position of the part by experience, thereby avoiding the situation of assembly error.

[0070] If the sending of the first position information and the second position information to the preset database does not find data matched with the first position information and the second position information, an alarm prompt is sent.

[0071] It can be understood that the application adopts a double-layer error prevention scheme, that is, it is firstly determined whether the shape size of the part to be assembled is correct, and then the position information is used for secondary determination. Finally, when all are correct, the torque assembly list is obtained through the preset database. It can be understood that if any of the above two determination processes is incorrect, an alarm prompt is sent to remind the on-site assembly personnel.

[0072] Optionally, in the assembling process, third position information of the tightening unit is acquired;

[0073] The first preset condition comprises:

[0074] When the third position information matches the second position information of the part to be assembled, and the force moment of the bolt of the part to be assembled is greater than a preset moment value, a moment value corresponding to the bolt in the moment assembling list is called.

[0075] The second position information of the part to be assembled is bolt position information of the part to be assembled, and the third position information of the tightening unit is tightening position information for tightening the bolt on the part to be assembled.

[0076] It can be understood that, by the preset first condition, whether the third position information of the tightening unit matches the second position information of the part to be assembled is detected, and if so, when the moment value of the tightening unit is greater than a preset moment value, a moment value corresponding to the bolt in the moment assembling list is called, wherein the preset moment value is used to represent a moment mutation value of the bolt in a preliminary tightening process of the bolt of the part to be assembled.

[0077] Specifically, the initial position information of the tightening unit is acquired by the positioning calibration unit, and the third position information of the tightening unit is determined by the attitude sensor or the position sensor inside the tightening unit. The advantage of this design is that whether the third position information of the tightening unit matches the second position information of the part to be assembled is detected, so as to determine whether the second position information of the part to be assembled is collected correctly. If they do not match, it indicates that the second position information of the part to be assembled is collected incorrectly, and an error prompt is output for subsequent engineering and development personnel to repair.

[0078] It should be noted that, during the tightening process of the tightening unit, the moment value of the tightening unit increases rapidly from zero until it is greater than the preset moment, indicating that the tightening unit is under stress, triggering a moment list calling instruction, based on which the moment assembling list of the part to be assembled is acquired, and the moment value corresponding to the bolt in the moment assembling list is used to perform the assembling operation of the part to be assembled.

[0079] It should be further noted that when the moment value of the tightening unit reaches the preset moment, it indicates that the part to be assembled is in contact with the frame component, and thus the part to be assembled changes from a relaxed state to a pre-tightened state. At this time, the bolt begins to bear a large moment, and this state is used as a trigger condition to start calling the moment assembling list of the part to be assembled to complete the bolt tightening operation.

[0080] Optionally, the application further comprises the following steps:

[0081] Based on the acquired three-dimensional data and coordinate information of the frame components and the parts to be assembled, an image display interface is generated.

[0082] Based on the image display interface, the assembly state of the parts to be assembled is acquired.

[0083] It can be understood that the application generates an image display interface by using the three-dimensional data and coordinate information of the frame components and the parts to be assembled, thereby guiding the on-site operators to perform assembly operations, further improving assembly efficiency, avoiding assembly errors, and improving assembly efficiency.

[0084] Optionally, the application further comprises the following steps:

[0085] During the tightening process, the tightening force of the tightening unit is acquired in real time.

[0086] When the tightening force of the tightening unit reaches the design value of the torque assembly list, a first control instruction and a second control instruction are output.

[0087] Based on the first control instruction, the tightening unit is closed.

[0088] Based on the second control instruction, an alarm prompt is generated on the image display interface.

[0089] It can be understood that the application completes the bolt tightening operation of the parts to be assembled by the tightening unit, and when the tightening force of the tightening unit reaches the design value of the torque assembly list, a first control instruction and a second control instruction are output. Through the first control instruction, the tightening unit is closed, and through the second control instruction, a prompt message is generated on the image display interface to prompt the on-site assembly personnel.

[0090] In this embodiment, the assembly process of the parts to be assembled is synchronously displayed through the image display interface to guide the on-site workers to assemble. It can be understood that the application can quickly complete the assembly operation of the parts to be assembled on the basis of ensuring the correct pre-assembly position of the parts to be assembled. Moreover, during the operation process, the parts to be assembled can be accurately positioned, and the torque value of the parts to be assembled can be accurately acquired. In the actual assembly process, the technical problems of mismatching of parts, incorrect assembly position of parts, excessively high or low bolt torque of parts, and unqualified assembly quality due to changes in parts during the iteration process of vehicle models and versions are avoided, thereby meeting the high requirements of technology, quality, and operation for mixed production of multiple vehicle models for trial production of sample vehicles.

[0091] The reference numerals in the figure are: 1. Positioning frame; 2. Vision acquisition unit; 3. Tightening unit; 31. Electric tightening gun; 32. Tightening part; 33. Display screen; 34. Posture sensor; 4. Positioning calibration unit; 41. Positioning reference; 5. Main control unit; 51. Mounting bracket; 52. Main display; 53. Tightening controller; 54. Main unit; 55. Workbench; 6. Positioning bracket; 7. Frame component; 8. Parts to be assembled.

[0092] In one embodiment, the present invention further provides a vehicle assembly auxiliary device for implementing the vehicle assembly tightening method, the device comprising:

[0093] A positioning frame, wherein a plurality of visual acquisition units are evenly arranged at the top and bottom of the positioning frame;

[0094] A visual acquisition unit, for image information and position coordinate information; wherein the image information includes image information of the frame components and the parts to be assembled; the position information includes position information of the frame components, the parts to be assembled, and the tightening unit;

[0095] A tightening unit, used to fix the parts to be assembled on the frame components;

[0096] Positioning calibration unit, used to locate the initial position information of the tightening unit;

[0097] The main control unit is used to obtain the three-dimensional data and position information sent by the visual acquisition unit in real time and generate an image display interface.

[0098] Specifically, a positioning bracket for installing and positioning the frame component is further provided inside the positioning frame; a positioning pin for plugging with the frame component is provided at the upper end of the positioning bracket.

[0099] The main control unit includes a movable mounting bracket, a workbench for placing the tightening unit is provided in the middle of the mounting bracket; a main display for displaying an image display interface is provided on the mounting bracket above the workbench; a tightening controller for controlling the tightening unit and a host electrically connected to the tightening controller are also provided on the mounting bracket; wherein the host is respectively communicated with the tightening unit and the visual acquisition unit.

[0100] Specifically, the tightening unit includes: an electric tightening gun and a tightening piece connected to the front end of the electric tightening gun; in this embodiment, the tightening piece is a sleeve; wherein, a display screen is provided at the upper end of the electric tightening gun; a posture sensor and / or position sensor for detecting the position information of the tightening piece is also provided inside the electric tightening gun.

[0101] Among them, the positioning calibration unit is provided with multiple positioning pins; the positioning pins can be positioning bolts; when in use, the positioning bolts are tightened by the tightening unit, and when the positioning bolts are fixed to the positioning calibration unit, the state of the positioning bolts is determined by the posture sensor, thereby triggering the visual acquisition unit to collect the position information of the tightening unit.

[0102] In one embodiment, the present invention further provides a vehicle assembly tightening system, comprising:

[0103] A first acquisition module is configured to acquire three-dimensional data of a frame component and a part to be assembled pre-installed on the frame component;

[0104] A second acquisition module is configured to input the acquired three-dimensional data and coordinate information of the frame components and the parts to be assembled into a preset database to obtain a torque assembly list of the parts to be assembled;

[0105] a calling module configured to call a moment assembly list of the part to be assembled model in response to the part to be assembled meeting a first preset condition;

[0106] a sending module configured to send the torque assembly list to a display interface of the tightening unit;

[0107] The control module is configured to fix the parts to be assembled on the frame component according to the torque assembly list based on the user's operation instructions.

[0108] It is worth noting that although only some basic functional modules are disclosed in the embodiment of the present invention, it does not mean that the composition of the present system is limited to the above basic functional modules. On the contrary, what this embodiment wants to express is that on the basis of the above basic functional modules, those skilled in the art can arbitrarily add one or more functional modules in combination with the existing technology to form an infinite number of embodiments or technical solutions. In other words, this system is open rather than closed. Just because this embodiment only discloses individual basic functional modules, it cannot be considered that the scope of protection of the claims of the present invention is limited to the disclosed basic functional modules. At the same time, for the convenience of description, the above devices are described in terms of functions, which are divided into various units and modules. Of course, when implementing the present invention, the functions of each unit and module can be implemented in the same or one or more software and / or hardware.

[0109] The present invention provides an electronic device, comprising: a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the vehicle assembly tightening method.

[0110] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments described herein. It should be understood that these embodiments are provided to make the disclosure of this application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art. In the accompanying drawings, for the sake of clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to represent the same devices, and thus their descriptions will be omitted.

Claims

1. A vehicle assembly tightening method, characterized in that: The method comprises the following steps: Step 1: Acquire three-dimensional data and coordinate information of a vehicle frame component and parts to be assembled pre-installed on the vehicle frame component; Step 2: Input the acquired 3D data and coordinate information of the frame components and parts to be assembled into a preset database to obtain a torque assembly list of the parts to be assembled; Step 3: In response to the part to be assembled meeting the first preset condition, calling the torque assembly list of the part to be assembled; Step 4: Sending the torque assembly list to the display interface of the tightening unit; Step 5: Based on the user's operating instructions and in accordance with the torque assembly list, the parts to be assembled are fixed to the frame components; The step 2 includes: Acquiring three-dimensional data of the frame component and the parts to be assembled; Traversing a preset database to search for a three-dimensional model that matches the frame component and the parts to be assembled; If they match, then obtaining a torque assembly list of the parts to be assembled based on the coordinate information of the frame component and the parts to be assembled; The step of obtaining a torque assembly list of the parts to be assembled based on the coordinate information of the frame component and the parts to be assembled specifically includes: Acquiring first position information of the frame component; Acquiring second position information of the part to be assembled; Sending the first position information and the second position information to a preset database to obtain a torque assembly list of the parts to be assembled; In response to the part to be assembled meeting the first preset condition, calling the torque assembly list of the part to be assembled specifically includes: During the assembly process, obtaining third position information of the tightening unit; The first preset condition includes: When the third position information matches the second position information of the part to be assembled, and the torque of the bolt of the part to be assembled is greater than the preset torque value, the torque value corresponding to the bolt in the torque assembly list is called.

2. The vehicle assembly tightening method according to claim 1, characterized in that: Also includes: Generate an image display interface based on the acquired three-dimensional data and coordinate information of the frame components and parts to be assembled; Based on the image display interface, the assembly status of the parts to be assembled is obtained.

3. The vehicle assembly tightening method according to claim 2, characterized in that: The following steps are also included: During the tightening process, the tightening force of the tightening unit is obtained in real time; When the tightening force of the tightening unit reaches the design value of the torque assembly list, outputting a first control instruction and a second control instruction; Based on the first control instruction, shut down the tightening unit; as well as Based on the second control instruction, prompt information is generated on the image display interface.

4. A vehicle assembly auxiliary device, characterized in that: For implementing the vehicle assembly tightening method according to any one of claims 1 to 3, the device comprises: A positioning frame, wherein a plurality of visual acquisition units are evenly arranged at the top and bottom of the positioning frame; A visual acquisition unit, configured to acquire image information and position information; wherein the image information includes image information of the frame components and parts to be assembled; and the position information includes position information of the frame components, parts to be assembled, and the tightening unit; A tightening unit, used to fix the parts to be assembled on the frame components; Positioning calibration unit, used to locate the initial position information of the tightening unit; The main control unit is used to obtain the three-dimensional data and position information sent by the visual acquisition unit in real time and generate an image display interface.

5. The vehicle assembly assisting device according to claim 4, wherein: The tightening unit includes: an electric tightening gun and a tightening member connected to the front end of the electric tightening gun; wherein, a display screen is provided at the upper end of the electric tightening gun; and a posture sensor is also provided inside the electric tightening gun.

6. A vehicle assembly tightening system, characterized in that: Used to implement the method described in any one of claims 1 to 3; the system includes: A first acquisition module is configured to acquire three-dimensional data of a frame component and a part to be assembled pre-installed on the frame component; A second acquisition module is configured to input the acquired three-dimensional data and coordinate information of the frame components and the parts to be assembled into a preset database to obtain a torque assembly list of the parts to be assembled; a calling module configured to call a moment assembly list of the part to be assembled model in response to the part to be assembled meeting a first preset condition; a sending module configured to send the torque assembly list to a display interface of the tightening unit; The control module is configured to fix the parts to be assembled on the frame component according to the torque assembly list based on the user's operation instructions.

7. An electronic device, characterized in that: include: A processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method according to any one of claims 1 to 3.

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