Method and apparatus for computer-implemented monitoring of a bolt tightening process using a tightening system - Patents.com

Abstract

A method for computer-implemented monitoring of a bolt tightening process using a tightening system (100), the method comprising: a manually operated tightening tool (10) having an actuator (11) for rotating a bolt, the tightening tool (10) being configured to be switchable between a first operating mode in which the actuator (11) of the tightening tool (10) is operable in at least one tightening sequence and a second operating mode in which the actuator (11) of the tightening tool (10) is operable in a loosening sequence, the tightening and loosening sequences being controlled by a computer; the tightening system further comprises a processing unit (20) for processing the at least one parameter (P1, P2) received from the sensor unit (12), the processing unit (20) being configured to determine a state (ST) of the bolted connection based on the at least one parameter (P1, P2), the state (ST) having a first state indicative of a correct bolted connection and a second state indicative of a faulty bolted connection; the tightening tool (10) further comprises a user interface (30) for outputting connection information for the bolted connection; and the method further comprises a step of: receiving from the tightening tool (10) by the interface (21) a tightening sequence in a first operating mode and / or after completion of the tightening sequence, the tightening system further comprises a processing unit (20) for processing the at least one parameter (P1, P2) of the bolted connection based on the at least one parameter (P1, P2), the state (ST) having a first state indicative of a correct bolted connection and a second state indicative of a faulty bolted connection; the at least one parameter (P1, P2) of the bolted connection; determining a state (ST) of the bolted connection simultaneously with and / or after completion of the bolted connection; switching an actuator (11) of the tightening tool (10) from the first operating mode to the second operating mode if the state (ST) corresponds to a second state; and switching the tightening tool (10) from the second operating mode to a very first tightening sequence of the at least one tightening sequence of the first operating mode in order to re-tighten the bolts (51, 52, 53).

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for computer-implemented monitoring of the tightening process of a bolt using a tightening system.

[0002] Workpieces in large plant structures such as wind turbines are joined using bolts. Bolts are the main indicator of quality since they must last for more than 25 years under extreme conditions. Failure of a bolted connection can lead to the collapse of the entire structure. Therefore, the quality control of the tightening process of the bolted connections is crucial. For documentation reasons, all process steps in the tightening of the bolts must be monitored and stored in a monitoring system.

[0003] Currently, information about the tightening steps must be checked manually by an operator, and information about the technical parameters must be checked in different software systems, which takes a long time and provides only a subsequent manual quality control.

[0004] There are existing software tools for monitoring the bolt tightening process used in the automotive industry. These software tools guide the operator through the tightening process. Such software tools are sometimes combined with a positioning system to check if the operator is performing the process step in the correct place. Assembly line production guarantees that the product always ends up in the same place in the workshop. Therefore, it is easy to predetermine the bolt position of the product and thus to incorporate a positioning system for quality control.

[0005] Such existing software tools cannot be used in large plant structures because the working environment is different: in large plant structures, products or workpieces are moved or hoisted by a crane from one work station to another, so that the products or workpieces are not always in the same position in the work station; after the products reach the work station, there are many workers who all work around the products for a long time, which makes it difficult to use existing software tools from the automotive industry.

[0006] It is an object of the present invention to provide an easy method for monitoring the tightening process of a bolt using a tightening system.

[0007] This problem is solved by the independent claims.

[0008] Preferred embodiments of the invention are defined in the dependent claims.

[0009] The present invention provides a computer-implemented method for monitoring the tightening process of a bolt using a tightening system.

[0010] The tightening system comprises a manually operated tightening tool having an actuator for rotating the bolt, the actuator being configured to be switchable between a first operating mode in which the actuator of the tightening tool is operable in at least one tightening sequence and a second operating mode in which the actuator of the tightening tool is operable in a loosening sequence. Each of the tightening and loosening sequences has predefined operating parameters for the actuator of the tightening tool. Furthermore, the tightening tool has a sensor unit for determining at least one parameter of the bolted connection during and / or after completion of the tightening sequence. Each of the at least one parameter represents a quality measure of the bolted connection.

[0011] Further, the tightening system has a processing unit for processing the at least one parameter received from the sensor unit, the processing unit being configured to identify a state of the bolted connection based on the at least one parameter, the state having a first state indicative of a proper bolted connection and a second state indicative of a faulty bolted connection.

[0012] Additionally, the tightening system has a user interface for outputting connection information about the bolted connection that can be used to guide an operator through the tightening process or provide feedback to the operator.

[0013] In accordance with the method of the present invention, the following steps are performed during operation of the tightening system:

[0014] In step a) at least one parameter of the bolted connection is received from the tightening tool by the interface during and / or after completion of a tightening sequence in the first operating mode.

[0015] In step b) the condition of the bolted connection is determined simultaneously and / or after completion of the bolted connection.

[0016] Step c) involves switching the actuator of the tightening tool from the first operating mode to the second operating mode when the state of the bolted connection corresponds to a second state, i.e. when a failure of the bolted connection is indicated.

[0017] In step d) the tightening tool is switched from the second operating mode to the very first tightening sequence of the at least one tightening sequence of the first operating mode in order to re-tighten the bolt.

[0018] The method of the invention provides a simple and straightforward way to automate and monitor the tightening process of a bolt using a tightening system. In particular, the operator operating the tightening tool does not need to manually input any information into a software tool for quality monitoring. Furthermore, in case of a faulty bolted connection, there is no need to manually switch the operating mode of the tightening tool. If the bolted connection is identified by the processing unit as being faulty, the faulty bolted connection can be automatically loosened without manually switching the tightening tool. After finishing loosening the faulty bolted connection, the operating mode of the tightening tool is switched again and the bolt can be re-tightened without manually switching the tightening tool. As another advantage, if multiple tightening sequences are required to tighten a bolt, it is ensured that the re-tightening starts with the very first tightening sequence.

[0019] According to another preferred embodiment, the method comprises a further step e) of controlling an actuator of the tightening tool from the very first tightening sequence of the first operating mode to at least one subsequent tightening sequence in order to re-tighten the bolts according to a predetermined order of tightening sequences. According to this embodiment, it can be ensured that the complete number of tightening sequences is performed by the operator operating the tightening tool, regardless of the fact that in which of the tightening sequences an error occurs.

[0020] According to another preferred embodiment, the step of switching the clamping tool from the first operating mode to the second operating mode and / or from the second operating mode to the very first or one of the subsequent clamping sequences of the first operating mode is performed under automatic control of a processing unit, so that an operator does not have to perform any manual steps to control the clamping tool.

[0021] According to another preferred embodiment, the user interface outputs at least one parameter representative of the state of the bolted connection and / or a quality measure of the bolted connection as connection information on the display. By displaying the connection information on the display, a worker operating the tightening device can verify whether the bolted connection is correct (OK) or not (NOK, i.e. not OK). It is further preferred if the connection information is output in real time.

[0022] According to another preferred embodiment, step d) is started after carrying out the following steps: in step c1) receiving at least one parameter of the bolted connection from the tightening tool during and / or after the end of a loosening sequence in the second operating mode, and in step c2) determining whether the bolted connection has been fully loosened or not, thus making it possible to ensure that the bolted connection is fully loosened before a re-tightening of the bolt is started with a predefined number of tightening sequences.

[0023] The state of the connection information is updated every time an operator works on the bolt. Therefore, preferably, the display of the connection state of the bolt connection is suppressed by the user interface immediately after step c2) is completed.

[0024] According to another preferred embodiment, the tightening system further comprises a positioning unit configured to determine the position of the tightening tool with respect to a reference point of the product or workpiece to be bolted while performing the tightening or loosening process of the bolt, the processing unit being configured to perform the following steps: step e1) determining the position of the tightening tool while performing the tightening process of the bolt; step e2) storing the position of the tightening tool as a first position if the state of the bolted connection corresponds to the second state; step e3) releasing the tightening tool for loosening the bolt associated with the second state only if the current position of the tightening tool corresponds to the first position. Thus, a comparison is made between two positions of the tightening tool, the first position of which corresponds to the working position of the bolt marked as bad; the second position of the tightening tool corresponds to the working position of the bolt that needs to be loosened. If these two positions match, the tightening tool is released (i.e. its actuator can be controlled to start rotating) and the loosening process can be started. If these positions do not match, the tightening tool is not released. Thus, the operator is not controlled to rotate its actuator. As a result, the operator receives direct tactile feedback as to whether or not he is working with the correct bolt, and as a result, errors can be minimized or even avoided.

[0025] According to another preferred embodiment, a counter associated with each bolted connection is incremented by one if the state of the bolted connection corresponds to the second state, the counter starting from a predefined starting value if the state of the bolted connection first corresponds to the second state and from the last stored value if the state of the bolted connection corresponds to the second state at each subsequent time. Preferably, an instruction to use a new bolt is output to a user interface if the actual value of the counter exceeds a predefined threshold. This particular embodiment can be combined with a storage system built with a "kanban" logic that allows monitoring whether an operator has actually taken a new bolt or not.

[0026] Besides the method described above, the invention also relates to an apparatus for computer-implemented monitoring of the tightening process of a bolt using a tightening system, which apparatus is configured to carry out the method according to the invention or one or more preferred embodiments of the method according to the invention.

[0027] The invention further relates to a computer program product comprising a program code stored on a non-transitory machine-readable carrier, which program code, when executed on a computer, performs the method according to the invention or one or more preferred embodiments thereof.

[0028] Furthermore, the invention relates to a computer program comprising a program code, which performs the method according to the invention or one or more preferred embodiments thereof when the program code runs on a computer.

[0029] One embodiment of the present invention will now be described in detail with reference to the accompanying drawings. [Brief description of the drawings]

[0030] [Figure 1]FIG. 1 is a schematic diagram illustrating a tightening system for computer-implemented monitoring of a bolt tightening process according to the present invention. [Diagram 2] 2 is a flow chart illustrating the different steps according to the method of the present invention according to a basic embodiment. [Diagram 3] FIG. 2 is a schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating a tightening tool of the tightening system according to the present invention; [Figure 4] FIG. 2 is another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention; [Diagram 5] FIG. 11 is yet another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention. [Figure 6] FIG. 11 is yet another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention. [Figure 7] FIG. 11 is yet another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention. [Figure 8] FIG. 11 is yet another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention. [Figure 9]FIG. 11 is yet another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention. [Figure 10] FIG. 11 is yet another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention. [Figure 11] FIG. 11 is yet another schematic diagram showing a workpiece being bolted by three bolts and a display screen output to a user interface showing the progress of the bolting for an operator operating the tightening tool of the tightening system according to the present invention.

[0031] 1 shows a schematic diagram of a tightening system 100 for computer-implemented monitoring of the bolt tightening process according to the invention. The tightening system 100 is used, purely by way of example, to tighten three bolts 51, 52, 53 of a workpiece 50, e.g. a wind turbine. However, the workpiece 50 may be any product of a large plant structure that is attached to another product.

[0032] The tightening system 100 comprises a manually operated tightening tool 10, a processing unit 20 and a user interface 30. The tightening system 100 may optionally comprise a positioning unit 40.

[0033] The tightening tool 10 comprises an actuator 11, a sensor unit 12 and a processor 13. The actuator 11 may be a motor connected to a tool holder for subsequently rotating the bolts 51, 52, 53. The tightening tool 10 is configured to be switchable between a first and a second operating mode. The switching between the first and second operating modes is performed under the control of the processor 13. In the first operating mode, the actuator 11 is rotated in a first rotation direction (forward direction) to tighten the bolts 51, 52, 53. In the second operating mode, the actuator is rotated in a second rotation direction (reverse direction) opposite to the first rotation direction to loosen the bolts 51, 52, 53.

[0034] In a first operating mode, the actuator 11 of the tightening tool 10 is operable in one or more tightening sequences, each having predefined control parameters, e.g. rotational speed and / or torque, etc., for the actuator 11 of the tightening tool 10 in order to reach one or more predefined parameters, e.g. torque and / or angle, etc., of the bolted connection during and / or after the tightening process. These predefined parameters P1, P2 represent quality measures of the bolted connection (see display screens in Figs. 3 to 11 referred to later).

[0035] If the bolts 51, 52, 53 have to be tightened in multiple tightening sequences, the tightening process is performed in multiple steps. For example, in a first step, the bolts 51, 52, 53 are tightened to 75% of the final torque. After finishing the first step, it is necessary to wait for the bolts 51, 52, 53 to settle. After a short interruption, the tightening process is finished by tightening the last 25% to reach the final torque.

[0036] In the second mode of operation, the actuator 11 of the fastening tool 10 is operable in a loosening sequence in which the actuator 11 of the fastening tool 10 is controlled to rotate in a second rotational direction in order to fully loosen the bolts 51, 52, 53.

[0037] The sensor unit 12 comprises one or more sensors, e.g. torque sensors and / or rotational speed sensors and / or force sensors etc. The sensor unit 12 is adapted to determine one or more parameters P1, P2 of the bolted connection during and / or after the tightening and loosening sequences, respectively.

[0038] The processing unit 20 comprises a first interface 21 , a second interface 22 , an optional third interface 23 and a processor 24 .

[0039] The processing unit 20 is connected to the tightening tool 10 via a first interface 21 for providing respective control data to switch the tightening tool 10 between the first and second operating modes and for applying appropriate control data for the respective tightening sequence in the first operating mode.

[0040] Furthermore, the processing unit 20 receives one or more parameters P1, P2 acquired by the sensor units 12 via the first interface 21 (see display screens in Figures 3 to 11) in order to determine a status ST of the respective bolted connection based on the one or more parameters of the sensor units 12. The status ST of the bolted connection 12 has a first status ("OK") indicating a good bolted connection and a second status ("NOK") indicating a bad bolted connection.

[0041] The user interface 30 comprises a display 31 and an input means 32. The display 31 and the input means 32 can be combined in one user interface, for example a touch screen or the like. The display 31 displays information about the bolted connection, for example one or more parameters P1, P2 of the bolted connection, the success or failure of the bolted connection (i.e. the status "OK" or the status "NOK"), etc. The information output via the display 31 makes it possible to guide an operator in the process of tightening a number of bolts 51, 52, 53. Such examples of display screens are shown in Figs. 3 to 11, which will be referred to later.

[0042] The user interface 30 is connected to the processing unit 20 via the second interface 22. The information displayed on the display 31 is determined by the processor 24 of the processing unit 20 based on sensor data received from the fastening tool 10 and optionally output via the second interface 22.

[0043] The positioning unit 40 comprises a sensor unit 41 and a processor 42. The sensor unit 41 consists of one or more sensors, e.g. one or more cameras, one or more proximity sensors, one or more radar sensors, etc. The processor 42 is adapted to determine the position of the tightening tool 10 relative to a reference point (not shown) of the product 52 to be bolted based on the sensor data received from the sensor unit 41 while performing the tightening or loosening process of the respective bolts 51, 52, 53.

[0044] In Fig. 2 a flow diagram is shown showing the different steps according to the method of the invention according to a basic embodiment. The method is based on the consideration that by monitoring the tightening process and controlling the tightening tool 10 by the processing unit 20 it is ensured that the correct sequence is performed by the operator even if a problem occurs. The monitoring and supervision by the processing unit 20 makes the whole tightening process easier. In case of a problem the tightening tool 10 is controlled with the next correct step which is additionally output via the user interface 30.

[0045] In a first step S1, the parameters P1, P2 of the bolted connection are received from the tightening tool 10 during and / or after the tightening sequence in the first operating mode. The processing unit 20 then determines (step S2) the state (ST) of the bolted connection simultaneously and / or after the end of the bolted connection. If the state ST corresponds to the second state NOK (i.e. ST=NOK), the tightening tool 10 is switched from the first operating mode to the second operating mode (step S3). In a final step S4, the tightening tool 10 is switched from the second operating mode to the very first tightening sequence of the at least one tightening sequence of the first operating mode in order to re-tighten the bolts 51, 52, 53 associated with the second state NOK.

[0046] 3-11 each show a schematic diagram on the left of a workpiece 50 on which three bolts 51, 52, 53 have to be tightened by an operator using the tightening tool 10. On the right side, an exemplary display screen is shown showing the progress of the bolt tightening. The display screen is output to the display 31 for information and guidance to the operator.

[0047] By way of example only, the bolts 51, 52, 53 have to be tightened in two tightening sequences, a first tightening sequence requiring a torque of, for example, 32 Nm and a second tightening sequence requiring a final torque of, for example, 40 Nm. It is envisaged here that the two tightening sequences are carried out by the same tightening tool 10 as described in relation to Fig. 1. The control of the tightening tool 10 with regard to the required parameters (rotational speed of the actuator, torque, etc.) is performed and monitored by the processing unit 20, as described above.

[0048] According to the work specifications, the bolts 51, 52, 53 are tightened sequentially in a first tightening sequence, followed by a tightening process in a second tightening sequence. The tightening progress is displayed on the display screen on the right side of each of Figs. 3 to 11.

[0049] 3-5 show the tightening of bolts 51, 52, 53 after a first tightening sequence has been performed. A successful bolted connection after the first tightening sequence is indicated by the suffix " / 1" for each of the bolt reference numbers 51, 52, 53 and by hatching from lower left to upper right.

[0050] Information about the respective bolted connection is displayed on a display screen. On the display screen, the process number PN for the current bolt tightening process is displayed together with the resultant state ST of the bolt tightening process and the parameters P1 and P2 acquired by the sensor unit 12 of the tightening tool 10 and the position information POS acquired by the positioning unit 40. The first parameter P1 represents for example the torque of the tightening process, which torque to be achieved must be within a predefined range. The second parameter P2 represents for example an angle, which angle to be achieved must be within a predefined range. The coordinates x / y / z of the position POS are shown relative to a given reference point (not shown) of the workpiece 50. Any suitable coordinate system can be used.

[0051] In Fig. 3 it is shown that the first (left) bolt 51 has been tightened with a first tightening sequence. Its process number on the display screen is PN=1. The acquired parameters P1, P2 and position POS are shown as P1=32, P2=10 and POS=10 / 20 / 30. From the acquired parameters P1, P2 the processing unit 20 determines that the status ST of the bolted connection 51 / 1 is correct, i.e. ST=OK.

[0052] In Fig. 4 it is shown that the second (middle) bolt 52 has been tightened with a first tightening sequence. Its process number on the display screen is PN=2. The acquired parameters P1, P2 and positions POS are shown as P1=32, P2=9 and POS=10 / 20 / 32. From the acquired parameters P1, P2 the processing unit 20 determines that the status ST of the bolted connection 52 / 1 is correct, i.e. ST=OK.

[0053] In Fig. 5 it is shown that the third (right) bolt 53 has been tightened with the first tightening sequence. Its process number on the display screen is PN=3. The acquired parameters P1, P2 and position POS are shown as P1=32, P2=11 and POS=10 / 20 / 34. From the acquired parameters P1, P2 the processing unit 20 determines that the status ST of the bolted connection 53 / 1 is correct, i.e. ST=OK.

[0054] 6-8 show the tightening of bolts 51, 52, 53 after the second tightening sequence has been performed. The successful bolted connection after the second tightening sequence is indicated by the suffix " / 2" and cross hatching for each of the bolt reference numbers 51, 52, 53.

[0055] In Fig. 6 it is shown that the first (left) bolt 51 has been tightened with the second tightening sequence. Its process number on the display screen is PN=4. As an alternative display option the line PN=1 may be overwritten. The acquired parameters P1, P2 and the position POS are shown as P1=40, P2=15 and POS=10 / 20 / 30. From the acquired parameters P1, P2 it is determined by the processing unit 20 that the status ST of the bolted connection 51 / 2 is correct, i.e. ST=OK.

[0056] In Fig. 7 it is shown that the second (middle) bolt 52 has been tightened with a second tightening sequence. Its process number on the display screen is PN=5. As an alternative display option the line PN=2 may be overwritten. The acquired parameters P1, P2 and the position POS are shown as P1=40, P2=16 and POS=10 / 20 / 32. From the acquired parameters P1, P2 it is determined by the processing unit 20 that the status ST of the bolted connection 52 / 2 is correct, i.e. ST=OK.

[0057] In FIG. 8 it is shown that the third (right) bolt 53 has been tightened with the second tightening sequence. Its process number on the display screen is PN=6. As an alternative display option the line PN=3 may be overwritten. The acquired parameters P1, P2 and the position POS are shown as P1=40, P2=30 and POS=10 / 20 / 34. From the acquired parameters P1, P2 it is determined by the processing unit 20 that the state ST of the bolted connection 53 / 2 is bad, i.e. ST=NOK. This is shown on the display screen by the highlighted line PN=6. Furthermore the bolted connection of bolt 53 is shown by 53 / F with a different hatching.

[0058] As a result of a faulty bolted connection, the bolt 53 has to be loosened and both, i.e. the first and the second tightening sequences, have to be repeated. Following the identification of the status ST corresponding to NOK (second state), the tightening tool 10 is automatically switched from the first operating mode (for tightening the bolt) to the second operating mode (for loosening the bolt), i.e. the direction of rotation is reversed. The switching from the first operating mode to the second operating mode is performed automatically under the control of the processing unit 20.

[0059] As a next step, the operator has to loosen the bolt 53. In order to avoid that the operator loosens one of the two otherwise correctly tightened bolts 51, 52, the positioning unit 40 is configured to release the tightening tool for loosening the bolt 53 only if the tightening tool 10 is in the correct position. To do this, the positioning unit 40 is configured to determine the position of the tightening tool 10 at the same time that the tightening process of the bolts 51, 52, 53 is carried out. If the state ST (here 53 / F) of the bolted connection corresponds to NOK, the position of the tightening tool (having the coordinates 10 / 20 / 34 in this example) is stored as a first position in a memory not shown. If the operator wants to loosen the bolt 53 (or any bolt), the position of the tightening tool is determined again. If the current position of the tightening tool 10 (having the coordinates 10 / 20 / 34) corresponds to the stored first position, the tightening tool 10 is released so that the bolt 53 can be loosened.

[0060] 9-11 show the loosening and retightening of bolt 53. A successful bolted connection after a first tightening sequence is again indicated by the suffix " / 1" on bolt reference number 53 and hatching from bottom left to top right. A successful bolted connection after a second tightening sequence is again indicated by the suffix " / 2" on bolt reference number 53 and cross hatching.

[0061] 9 shows the situation where the third (right) bolt 53 has been loosened. In this display screen, the successful loosening is visualized by suppressing the display of rows PN=3 and PN=6. The other rows of the display screen remain unchanged.

[0062] In figure 10 it is shown that the third (right) bolt 53 has been tightened with the first tightening sequence. Its process number on the display screen is now PN=3.1. The acquired parameters P1, P2 and position POS are shown as P1=32, P2=11 and POS=10 / 20 / 34. From the acquired parameters P1, P2 it is determined by the processing unit 20 that the status ST of the bolted connection 53 / 1 is correct, i.e. ST=OK.

[0063] In Fig. 11 it is shown that the third (right) bolt 53 has been tightened with the second tightening sequence. Its process number on the display screen is PN=6.1. The acquired parameters P1, P2 and position POS are shown as P1=40, P2=14 and POS=10 / 20 / 34. From the acquired parameters P1, P2 the processing unit 20 determines that the status ST of the bolted connection 53 / 2 is correct, i.e. ST=OK.

[0064] In a not shown embodiment, a counter associated with each bolted connection can be incremented by one if the bolted connection's status ST corresponds to NOK, the counter starting from a predefined starting value (e.g. 0) the first time the bolted connection's status ST corresponds to NOK and from the last stored value the respective time the bolted connection's status ST corresponds to NOK. Preferably, an instruction to use a new bolt is output to a user interface if the actual value of the counter exceeds a predefined threshold. This particular embodiment can be combined with a storage system built with a "kanban" logic that allows monitoring whether an operator has actually taken a new bolt from the storage.

[0065] In summary, the proposed method has several advantages: It can be ensured that the correct tightening sequence is performed even in the case of a problem. Furthermore, this makes the entire work with the tightening system easier: if there is a problem, the worker is guided through the work process, thus avoiding manual errors.

[0066] Because there is a data connection between the tightening tool and the processing unit, there are no mistakes or fraudulent acts that can occur by the operator. The results of a bad connection are automatically deleted by the processing unit. As a result, there is no risk that the operator will miss a bad connection. Furthermore, the documentation is clean for quality reasons.

[0067] The functionality of the positioning unit allows large plant structures to utilize it to make production fail-safe.

[0068] As a result, a new operator guidance system is provided that can ensure zero-defect manufacturing for large plant structures, and the system can be used as the main system for digital quality control in large plant structures.

Claims

1. A method for computer-implemented monitoring of a bolt tightening process using a tightening system (100), comprising: A manually operated tightening tool (10) having an actuator (11) for rotating the bolt, the tightening tool (10) comprising: a first operating mode in which the actuator (11) of the fastening tool (10) is operable in at least one fastening sequence; a second mode of operation in which the actuator (11) of the tightening tool (10) is operable in a loosening sequence; and each of the tightening sequence and the loosening sequence having predetermined operating parameters for the actuator (11) of the tightening tool (10); The tightening tool (10) further comprises a sensor unit (12) for determining at least one parameter (P1, P2) of the bolted connection during and / or after the tightening sequence, each of the at least one parameter (P1, P2) represents a quality measure of the bolted connection, The tightening system (100) further comprises a processing unit (20) for processing the at least one parameter (P1, P2) received from the sensor unit (12), the processing unit (20) being configured to determine a state (ST) of the bolted connection based on the at least one parameter (P1, P2), The state (ST) has a first state indicative of a proper bolted connection and a second state indicative of a faulty bolted connection, and the fastening system (100) further comprises: a user interface (30) for outputting connection information about the bolted connection; The method comprises the steps of: a) receiving, by an interface (21), at least one said parameter (P1, P2) of said bolted connection from said tightening tool (10) during and / or after a tightening sequence in said first operating mode; b) determining the state (ST) of the bolted connection simultaneously and / or after completion of the bolted connection; c) switching the actuator (11) of the tightening tool (10) from the first operating mode to the second operating mode if the state (ST) corresponds to the second state; d) switching the tightening tool (10) from the second operating mode to the very first tightening sequence of the at least one tightening sequence of the first operating mode in order to re-tighten the bolts (51, 52, 53); having The tightening system (100) further comprises a positioning unit configured to determine the position of the tightening tool (10) with respect to a reference point of the product to be bolted while performing the tightening or loosening process of the bolts (51, 52, 53), the processing unit (20) performing the following steps: e1) performing a tightening process of the bolts (51, 52, 53) while locating the tightening tool (10); e2) storing a position of the tightening tool (10) as a first position if the state of the bolted connection corresponds to a second state; e3) releasing the tightening tool (10) for loosening the bolts (51, 52, 53) associated with the second state only if the current position of the tightening tool (10) corresponds to the first position; is configured to run method.

2. The method further comprises the steps of: e) controlling an actuator (11) of the tightening tool (10) from the very first tightening sequence of the first operating mode to at least one subsequent tightening sequence in order to re-tighten the bolts (51, 52, 53) according to a predetermined order of tightening sequences.

3. 2. The method of claim 1, wherein the step of switching the tightening tool (10) from the first operating mode to the second operating mode and / or switching the tightening tool (10) from the second operating mode to the very first tightening sequence or one of the subsequent tightening sequences of the first operating mode is performed under automatic control of the processing unit (20).

4. 2. The method according to claim 1, wherein the user interface (30) outputs the state (ST) of the bolted connection and / or at least one of the parameters (P1, P2) representative of a quality measure of the bolted connection as connection information on a display (31).

5. The method of claim 4 , further comprising outputting the connection information in real time.

6. The next step, i.e. c1) receiving at least one said parameter of said bolted connection from said tightening tool (10) during and / or after said loosening sequence in said second operating mode; c2) determining whether the bolted connection has been completely loosened; 2. The method of claim 1, further comprising: starting step d) after executing

7. The method of claim 6, further comprising suppressing display of the bolted connection by the user interface (30) immediately after step c2) is completed.

8. 2. The method of claim 1, further comprising: incrementing a counter associated with each bolted connection by one when the state of the bolted connection corresponds to the second state, wherein the counter starts from a predetermined starting value when the state of the bolted connection first corresponds to the second state and starts from a last stored value when the state of the bolted connection corresponds to the second state at each subsequent time.

9. 9. The method of claim 8, further comprising outputting an instruction to the user interface (30) to use a new bolt (51, 52, 53) if the actual value of the counter exceeds a predetermined threshold value.

10. 1. An apparatus for computer-implemented monitoring of a tightening process of a bolt (51, 52, 53) using a tightening system, the apparatus comprising: a manually operated tightening tool (10) having an actuator (11) for rotating the bolt, the tightening tool (10) being configured to be switchable between a first operating mode in which the actuator (11) of the tightening tool (10) is operable in at least one tightening sequence and a second operating mode in which the actuator (11) of the tightening tool (10) is operable in a loosening sequence, each of the tightening and loosening sequences having predefined operating parameters for the actuator (11) of the tightening tool (10), and a sensor unit for determining at least one parameter of a bolted connection during and / or after completion of a tightening sequence, each of the at least one parameter representing a quality measure of the bolted connection, the apparatus further comprising: a processing unit (20) for processing the at least one parameter received from the sensor unit, the processing unit (20) being configured to determine a state of the bolted connection based on the at least one parameter, the state having a first state indicative of a good bolted connection and a second state indicative of a bad bolted connection, the apparatus further comprising: a user interface (30) for outputting connection information about the bolted connection; The processing unit (20) performs the following steps: a) receiving at least one said parameter of said bolted connection from said tightening tool (10) during and / or after a tightening sequence in said first operational mode; b) determining said condition of said bolted connection simultaneously and / or after completion of said bolted connection; c) switching the actuator (11) of the fastening tool (10) from the first operating mode to the second operating mode if the condition corresponds to the second condition; d) switching the tightening tool (10) from the second operating mode to the very first tightening sequence of the at least one tightening sequence of the first operating mode in order to re-tighten the bolts (51, 52, 53); is configured to run The apparatus further comprises a positioning unit configured to determine the position of the tightening tool (10) with respect to a reference point of the product to be bolted while performing the tightening or loosening process of the bolts (51, 52, 53), the processing unit (20) performing the following steps: e1) performing a tightening process of the bolts (51, 52, 53) while locating the tightening tool (10); e2) storing a position of the tightening tool (10) as a first position if the state of the bolted connection corresponds to a second state; e3) releasing the tightening tool (10) for loosening the bolts (51, 52, 53) associated with the second state only if the current position of the tightening tool (10) corresponds to the first position; is configured to run Device.

11. The apparatus according to claim 10, wherein the apparatus is configured to perform a method according to any one of claims 2 to 9.

12. A computer program product comprising a program code stored on a non-transitory machine-readable carrier, the program code causing the method of any one of claims 1 to 9 to be performed when the program code is executed on a computer.

13. A computer program comprising a program code, the program code causing the method according to any one of claims 1 to 9 to be performed when the program code is run on a computer.

14. A method for manufacturing a wind turbine, comprising the steps of: The wind turbine comprises a bolted connection with at least three bolts (51, 52, 53) and a device according to claim 10, or comprises a bolted connection with at least three bolts (51, 52, 53), the bolts (51, 52, 53) being tightened by implementing a method according to any one of claims 1 to 9.

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