Patent Publication Number: US-2023142633-A1

Title: Method of operating fastening apparatus and fastening apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of non-provisional U.S. patent application Ser. No. 17/344,026, filed on Jun. 10, 2021, which claims priority to and the benefit of Korean Patent Application No. 10-2020-0075974, filed on Jun. 22, 2020, the entire contents of each of which are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to a method of operating a fastening apparatus and the fastening apparatus. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     Teaching methods, which enable robots used for production automation to move to desired positions, are broadly classified into a method that uses a teaching pendant including a display device, a keyboard, and the like that enables input and output for controlling the robot or executing programs, and a method in which a person applies force directly to the robot to move the robot. Examples the automated robot may include a nut runner that serves to fasten a fastener such as a nut to a fastening hole formed in a workpiece. 
     However, we have discovered that types of tasks, which can be performed by the automated robot, are extremely limited. For example, because the number and positions of fastening tools of the nut runner, which perform the fastening operations, are preset, there is a problem in that types and sizes of workpieces, which are to be fastened by the nut runner, are extremely limited. 
     In addition, when teaching the automated robot using the teaching pendant, the operation of the automated robot using theoretically derived position data is not often suitable for actual sites. For this reason, the position data is desired to be modified several times, which causes a problem in that an excessively large amount of time is required for the step of teaching the robot before performing the main task. In addition, in the case in which a person applies force directly to the robot to teach the robot, expensive components such as a force sensor are required, which causes a problem in that a large amount of costs are required to equip an automation production line. 
     SUMMARY 
     The present disclosure enables a robot used for production automation to perform tasks on various types of workpieces, shorten the time it takes to perform a step of teaching the robot, and reduce costs required to equip an automation production line. 
     In one form of the present disclosure, a method of operating a fastening apparatus includes: a fastening apparatus preparing step of preparing a fastening apparatus including n fastening tools; a first workpiece disposing step of disposing a first workpiece having m fastening holes at one side of the fastening apparatus; a first fastening tool disposing step of disposing each of the n the fastening tools above any one of the m fastening holes; and a first storage step of storing, in a control unit, positions of the n fastening tools in the first fastening tool disposing step, in which m is larger than n, and the plurality of first fastening tool disposing steps and the plurality of first storage steps are alternately performed. 
     The first fastening tool disposing steps and the first storage steps may be performed [m/n]+1 times (in which [m/n] is a maximum integer that does not exceed m/n), respectively. 
     In the first fastening tool disposing step, the fastening apparatus may be primarily moved in a vertical direction, and then the n fastening tools of the fastening apparatus may be moved in a horizontal direction. 
     In the first fastening tool disposing step, the n fastening tools may be simultaneously moved primarily in the vertical direction. 
     In the first fastening tool disposing step, the n fastening tools may be sequentially moved in the horizontal direction. 
     A movement of the n fastening tools of the fastening apparatus in a circumferential direction A and a movement of the n fastening tools of the fastening apparatus in a radial direction B may be performed independently, and in the first fastening tool disposing step, the n fastening tools may be moved in the circumferential direction A and then moved in the radial direction B. 
     The movement of the n fastening tools of the fastening apparatus in the circumferential direction A and the movement of the n fastening tools of the fastening apparatus in the radial direction B may be performed independently, and in the first fastening tool disposing step, the n fastening tools may be moved in the radial direction B and then moved in the circumferential direction A. 
     The method may further include: after the first storage step, a second workpiece disposing step of disposing a second workpiece comprising p fastening holes at one side of the fastening apparatus; a second fastening tool disposing step of disposing each of the n fastening tools above any one of the p the fastening holes; and a second storage step of storing, in the control unit, positions of the n fastening tools in the second fastening tool disposing step. 
     When the first workpiece and the second workpiece are workpieces identical in type to each other, the information stored in the control unit in the first storage step may be removed from the control unit after the second storage step. 
     When the first workpiece and the second workpiece are workpieces different in type from each other, the information stored in the control unit in the first storage step and the information stored in the control unit in the second storage step may coexist in the control unit after the second storage step. 
     In the first fastening tool disposing step, the fastening tool of the fastening apparatus may be moved in the horizontal direction, and then the fastening apparatus may be moved secondarily in the vertical direction. 
     In the first fastening tool disposing step, the fastening tool of the fastening apparatus may be moved in the horizontal direction, and then the fastening apparatus may be moved secondarily in a vertically downward direction. 
     The method may further include: after the first storage step, a fastening performing step of performing a fastening operation on the m fastening holes provided in the first workpiece by loading the information (i.e., the positions of the n fastening tools) stored in the control unit in the first storage step, using the n fastening tools, and using a fastener. 
     In the fastening performing step, when each of the n fastening tools performs the fastening operation on any one of the m fastening holes provided in the first workpiece and then moves to another fastening hole, the time it takes for one of the n fastening tools to move may be equal to the time it takes for the other fastening tools to move. 
     In order to achieve the above-mentioned object, another aspect of the present disclosure provides a fastening apparatus including: a plurality of fastening tools; a first movement mechanism configured to rotate the plurality of fastening tools in a circumferential direction A; a second movement mechanism configured to rectilinearly move the fastening tools in a radial direction B; and a third movement mechanism configured to rectilinearly move the fastening tools in a vertical direction C, in which the first movement mechanism includes a closed-curve guide unit having a closed-curve shape and configured to define a route along which the fastening tool rotates in the circumferential direction A, and the plurality of closed-curve guide units is provided. 
     The second movement mechanism may include: a screw unit extending in the radial direction B, having a screw structure, and configured to rotate so that the fastening tool rectilinearly moves in the radial direction B; a horizontal movement unit provided to engage with the screw unit and coupled, at one side, to the fastening tool; and a horizontal guide unit coupled to the horizontal movement unit in order to define a route along which the fastening tool rectilinearly moves in the radial direction B, and the plurality of horizontal guide units and the plurality of horizontal movement units may be provided. 
     One end portion of any one of the plurality of horizontal guide units and one end portion of another of the plurality of horizontal guide units may meet together, and a stepped portion may be formed in a region in which the plurality of horizontal guide units meets together. 
     According to the present disclosure, it is possible to enable the robot used for production automation to perform tasks on various types of workpieces, shorten the time it takes to perform the step of teaching the robot, and reduce costs required to equip an automation production line. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
         FIG.  1    is a perspective view illustrating an entire structure of a fastening apparatus according to one form of the present disclosure; 
         FIG.  2    is a perspective view illustrating structures fastening tools, a first movement mechanism, and a second movement mechanism of the fastening apparatus according to some forms of the present disclosure; 
         FIG.  3    is a perspective view illustrating an example of the structure of the first movement mechanism of the fastening apparatus according to one form of the present disclosure; 
         FIG.  4    is a perspective view illustrating an example of the structure of the second movement mechanism of the fastening apparatus according to another form of the present disclosure; and 
         FIG.  5    is a perspective view illustrating an example of a display provided on a control unit of the fastening apparatus according to one form of the present disclosure. 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     Hereinafter, a fastening apparatus and a method of operating the fastening apparatus according to some forms of the present disclosure will be described with reference to drawings. 
       FIG.  1    is a perspective view illustrating an entire structure of a fastening apparatus according to one form of the present disclosure, and  FIG.  2    is a perspective view illustrating structures fastening tools, a first movement mechanism, and a second movement mechanism of the fastening apparatus according to some forms of the present disclosure.  FIG.  3    is a perspective view illustrating an example of the structure of the first movement mechanism of the fastening apparatus according to another form of the present disclosure, and  FIG.  4    is a perspective view illustrating an example of the structure of the second movement mechanism of the fastening apparatus according to one form of the present disclosure. 
     As illustrated in  FIGS.  1  and  2   , a fastening apparatus  10  may include a plurality of fastening tools  100 . For example, the plurality of fastening tools  100  may be a plurality of nut runners.  FIGS.  1  and  2    illustrate that the eight fastening tools  100  are provided on the fastening apparatus  10 . However, the number of fastening tools  100  is not limited thereto. 
     According to the present disclosure, the fastening apparatus  10  may move in a vertical direction and a horizontal direction. In more detail, referring to  FIGS.  3  and  4   , the fastening apparatus  10  may include first movement mechanisms  200  configured to rotate the fastening tools  100  in a circumferential direction “A”, second movement mechanisms  300  configured to rectilinearly move the fastening tools  100  in a radial direction “B”, and a third movement mechanism  400  configured to rectilinearly move the fastening tools  100  in a vertical direction (i.e., an upward/downward direction). 
     Referring to  FIG.  3   , the first movement mechanism  200  may include a closed-curve guide unit  210  that has a closed-curve shape and provides a route along which the fastening tool  100  (see  FIG.  2   ) rotates in the circumferential direction A. As illustrated in  FIGS.  2  and  3   , the closed-curve guide unit  210  may have a circular shape. 
     In this case, a gear portion  210 a may be provided at one side of the closed-curve guide unit  210 , and a pinion gear  220  may engage with the gear portion  210 a. Therefore, when the pinion gear  220  rotates, the pinion gear  220  may move in the circumferential direction A along the closed-curve guide unit  210  by means of the engagement between the gear portion  210 a and the pinion gear  220 . In this case, the fastening tool  100  may be connected to a lower portion of the first movement mechanism  200 . In this case, when the pinion gear  220  rotates, the fastening tool  100  may also rotate in the circumferential direction A along the closed-curve guide unit  210 . Meanwhile,  FIG.  3    illustrates that the gear portion  210 a is provided on a radial outer surface of the closed-curve guide unit  210  and the pinion gear  220  is also provided to face the radial outer surface of the closed-curve guide unit  210 . However, instead, the gear portion  210 a may be provided on a radial inner surface of the closed-curve guide unit  210 , and the pinion gear  220  may also be provided to face the radial inner surface of the closed-curve guide unit  210 . Meanwhile, the first movement mechanism  200  may further include a first power unit  230  configured to provide power to rotate the pinion gear  220 . 
     Meanwhile, a rotational speed of the first power unit  230  may be relatively higher than a rotational speed required for the pinion gear  220 . In this case, the rotational speed needs to be reduced before the power of the first power unit  230  is transmitted to the pinion gear  220 . To this end, a speed reducer (not illustrated) may be provided in a power transmission path between the first power unit  230  and the pinion gear  220 . In particular, according to the present disclosure, the speed reducer may be provided in the pinion gear  220 . That is, the pinion gear  220  and the speed reducer may have an integrated structure. This is advantageous because a separate space for providing the pinion gear  220  is not additionally required. 
     Meanwhile, the plurality of first movement mechanisms  200  may be provided, and the number of first movement mechanisms  200  may be equal to the number of fastening tools  100 . 
     Therefore, the plurality of first movement mechanisms  200  and the plurality of fastening tools  100  may correspond to one another in a one-to-one manner. In this case, the movements of the plurality of fastening tools  100  in the circumferential direction A may be individually performed. 
     Meanwhile, according to the present disclosure, the plurality of closed-curve guide units  210  may be provided. In more particularly, the plurality of closed-curve guide units  210  may have a concentric structure having the same central axis.  FIG.  2    illustrates that the two closed-curve guide units  210  each having a circular shape are disposed to have the concentric structure, one side of the fastening tool  100  is coupled to one of the two closed-curve guide units  210  which has a large outer diameter, and the other side of the fastening tool  100  is coupled to the other of the two closed-curve guide units  210  which has a small outer diameter. 
     According to the present disclosure, it is possible to solve a problem of deformation of the first movement mechanism  200  including the closed-curve guide units  210  caused by weights of the fastening tools  100  or loads applied to the fastening tools  100  while the fastening tools  100  move in the circumferential direction A. In particular, as described below, according to the present disclosure, the fastening tool  100  may be moved in the circumferential direction A by force applied by a person during a teaching process of the fastening apparatus  10 . If the single closed-curve guide unit  210  is provided, there may occur a problem in that the closed-curve guide unit  210  is distorted during the teaching process of the fastening apparatus  10 . However, according to the present disclosure, the plurality of closed-curve guide units  210  having the concentric structure may be coupled to the fastening tools  100 , respectively, such that overall rigidity of the closed-curve guide units  210  may be improved, thereby solving the problem of deformation of the first movement mechanism  200 . 
     Meanwhile, referring to  FIG.  4   , the second movement mechanism  300  may include a screw unit  310  extending in the radial direction B and configured to rotate so that the fastening tool  100  (see  FIG.  2   ) rectilinearly moves in the radial direction B. 
     In this case, the screw unit  310  may have a screw structure, and a horizontal movement unit  320  engages with the screw structure. Therefore, when the screw unit  310  rotates about a central axis of the screw unit  310 , the horizontal movement unit  320  engaging with the screw structure may rectilinearly move in the radial direction B. In this case, the fastening tool  100  may be connected to one side of the second movement mechanism  300 . In more detail, the fastening tool  100  may be coupled to one side of the horizontal movement unit  320 . In this case, as the screw unit  310  rotates, the fastening tool  100  may also rectilinearly move in the radial direction B along with the horizontal movement unit  320 . Meanwhile, the second movement mechanism  300  may further include a second power unit  330  configured to provide power to rotate the screw unit  310 . 
     Meanwhile, the plurality of second movement mechanisms  300  may be provided, and the number of second movement mechanisms  300  may be equal to the number of fastening tools  100 . Therefore, the plurality of second movement mechanisms  300  and the plurality of fastening tools  100  may correspond to one another in a one-to-one manner. Therefore, the movements of the plurality of fastening tools  100  in the radial direction B may also be performed individually. 
     Next, referring to  FIG.  4   , the second movement mechanism  300  may further include a horizontal guide unit  340  coupled to the horizontal movement unit  320  in order to define a route along which the fastening tool  100  (see  FIG.  2   ) rectilinearly moves in the radial direction B. That is, the horizontal guide unit  340  is configured to define a predetermined route so that the horizontal movement unit  320  may rectilinearly moves along the predetermined route when the horizontal movement unit  320  is rectilinearly moved by the rotation of the screw unit  310 . Therefore, as illustrated in  FIG.  4   , a direction in which the horizontal guide unit  340  extends may be in parallel with a direction in which the screw unit  310  extends. 
     In this case, according to the present disclosure, the plurality of horizontal movement units  320  and the plurality of horizontal guide units  340  may be provided, and the horizontal movement units  320  may be coupled to the plurality of horizontal guide units  340 , respectively.  FIG.  4    illustrates that the two horizontal guide units  340  are provided in a row in the radial direction B and provided such that one end portion of the horizontal guide unit provided outside in the radial direction B and one end portion of the horizontal guide unit provided inside in the radial direction B meet together, and the horizontal movement units  320  are coupled to the two horizontal guide units  340 , respectively. 
     According to the present disclosure, it is possible to solve a problem of deformation of the second movement mechanism  300  including the horizontal guide units  340  caused by weights of the fastening tools  100  or loads applied to the fastening tools  100  while the fastening tools  100  move in the radial direction A. In particular, as described below, according to the present disclosure, the fastening tool  100  may be moved in the radial direction B by force applied by a person during the teaching process of the fastening apparatus  10 . If the single horizontal guide unit  340  and the single horizontal movement unit  320  are provided, there may occur a problem in that the horizontal guide unit  340  is distorted during the teaching process of the fastening apparatus  10 . However, according to the present disclosure, the plurality of horizontal guide units  340  is provided in a row in the radial direction B, and the plurality of horizontal movement units  320  coupled to the plurality of horizontal guide units  340  may be coupled to the fastening tools  100 , respectively, such that the overall rigidity of the horizontal guide units  340  may be improved, thereby solving the problem of deformation of the second movement mechanism  300 . Meanwhile, as illustrated in  FIG.  4   , the plurality of horizontal guide units  340  are provided in a row in the radial direction B, a stepped portion D may be provided in a region in which the plurality of horizontal guide units  340  meets together. 
     Meanwhile, referring to  FIG.  1   , the third movement mechanism  400  may include a vertical guide unit  410  extending in a vertical direction C and configured to define a route along which the fastening tool  100  rectilinearly moves in the vertical direction C. 
     In this case, a vertical movement unit  420  may be provided at one side of the vertical guide unit  410 , and the vertical movement unit  420  may move in the vertical direction C along the vertical guide unit  410 . In this case, the fastening tools  100  may be connected to one side of the third movement mechanism  400 . In this case, as the vertical movement unit  420  rectilinearly moves in the vertical direction C along the vertical guide unit  410 , the plurality of fastening tools  100  may also rectilinearly move in the vertical direction C. 
     Meanwhile, unlike the first movement mechanisms  200  and the second movement mechanisms  300 , the single third movement mechanism  400  may be provided. In more detail, the single third movement mechanism  400  may simultaneously move the plurality of fastening tools  100  in the vertical direction C. For example, the third movement mechanism  400  may include a connection body unit  430  connected to the vertical movement unit  420  and configured to fix the plurality of fastening tools  100 . When the connection body unit  430  moves along with the movement of the vertical movement unit  420 , the plurality of fastening tools  100  may also rectilinearly move simultaneously in the vertical direction C. 
     Meanwhile, according to the present disclosure, the fastening apparatus  10  or the fastening tools  100  may be moved by force applied by a person during the teaching process of the fastening apparatus  10 . In more detail, with the force applied by the person, the fastening apparatus  10  may be moved in the vertical direction C along the vertical guide unit  410 , and the plurality of fastening tools  100  may be moved in the circumferential direction A along the closed-curve guide units  210 , respectively, and moved in the radial direction B along the horizontal guide units  340 , respectively. 
     In this case, a magnitude of external force (i.e., the force applied by the person) required to move each of the fastening tools  100  in the circumferential direction A or the radial direction B may be 40 N to 60 N. For example, the configuration in which the external force required to move the fastening tool  100  in the circumferential direction A or the radial direction B is 50 N may mean that a minimum value of the external force required to move the fastening tool  100  in the circumferential direction A or the radial direction B is 50 N. If the external force required to move the fastening tool  100  in the circumferential direction A or the radial direction B is lower than  40  N, the fastening tool  100  may be moved by external impact or the like against a user&#39;s intention. In contrast, if the external force required to move the fastening tool  100  in the circumferential direction A or the radial direction B is higher than 60 N, an operating force applied by the person may be significantly low during the teaching process of the fastening apparatus  10 . 
     Meanwhile, as illustrated in  FIG.  1   , the fastening apparatus  10  may further include a display  500  configured to display visual information in order to enable the person to control the operations of the fastening apparatus  10  or the fastening tools  100  and store information on the positions of the fastening tools  100 . Hereinafter, a method of operating the fastening apparatus according to the present disclosure will be described. 
     The method of operating the fastening apparatus according to the present disclosure may include a fastening apparatus preparing step of preparing the fastening apparatus  10  including the n fastening tool  100 . For example, the fastening apparatus  10  may include the eight fastening tools  100 . 
     In addition, the method of operating the fastening apparatus according to the present disclosure may include a first workpiece disposing step of disposing a first workpiece including m fastening holes at one side of the fastening apparatus  10 . In this case, according to the present disclosure, m may be larger than n. For example, the first workpiece may include a total of twenty-two fastening holes. 
     Meanwhile, the method of operating the fastening apparatus according to the present disclosure may further include a first fastening tool disposing step of disposing each of the n fastening tools  100  above any one of the m fastening holes. For example, when the eight fastening tools and the twenty-two fastening holes are provided, the eight fastening tools  100  may be disposed above the eight fastening holes among the twenty-two fastening holes, respectively, in the first fastening tool disposing step. 
     In addition, the method of operating the fastening apparatus according to the present disclosure may further include a first storage step of storing, in a control unit, positions of the n fastening tools  100  disposed in the above-mentioned first fastening tool disposing step. For example, when the eight fastening tools and the twenty-two fastening holes are provided, the positions of the eight fastening tools  100  disposed in the first fastening tool disposing step may be stored in the control unit in the first storage step. The information on the positions of the fastening tools  100  stored in the first storage step may be loaded in the following fastening operation step using the fastening tools, and the fastening tools  100  may move to the portions above the fastening holes on the basis of the loaded information. Therefore, after the information is stored, the fastening operation of the fastening apparatus may be automatically performed on the fastening holes. 
     As described above, m may be larger than n. That is, the number of fastening holes provided in the first workpiece may be larger than the number of fastening tools  100  provided in the fastening apparatus  10 . Therefore, in a case in which the first fastening tool disposing step and the first storage step are performed only once, the fastening operations of the fastening tools  100  cannot be performed, in the fastening operation step later, on the fastening holes above which the fastening tools  100  are not disposed in the first fastening tool disposing step, among the plurality of fastening holes provided in the first workpiece. 
     Therefore, according to the present disclosure, the plurality of first fastening tool disposing steps and the plurality of first storage steps may be alternately performed. 
     In more detail, the first fastening tool disposing steps and the first storage steps may be performed [m/n]+1 times, respectively. In this case, [m/n] means a maximum integer that does not exceed m/n. For example, when the eight fastening tools and the twenty-two fastening holes are provided, the first fastening tool disposing steps and the first storage steps may be alternately performed [22/8]+1 times, that is, three times, respectively. In this case, in the first fastening tool disposing step which is performed second or subsequently, the fastening tools  100  may be disposed above the fastening holes above which the fastening tools  100  have not been disposed in the first fastening tool disposing step which has been performed first among the plurality of first fastening tool disposing steps. Further, in the first storage step which is performed second or subsequently, the information on the positions of the fastening tools  100  may be stored. As a result, in the later fastening operation step, the fastening operation may be automatically performed on all the fastening holes provided in the first workpiece. 
     Meanwhile, according to the present disclosure, in the first fastening tool disposing step, the fastening apparatus  10  including the fastening tools  100  may be moved primarily in the vertical direction, and then the fastening tools  100  of the fastening apparatus  10  may be moved in the horizontal direction. In this case, the primary movement of the fastening apparatus  10  in the vertical direction may be performed by the third movement mechanism  400  (see  FIG.  1   ), and the movements of the fastening apparatus  10  in the horizontal direction may be performed by the first movement mechanisms  200  (see  FIG.  3   ) and the second movement mechanisms  300  (see  FIG.  4   ). 
     Therefore, in the first fastening tool disposing step, the n fastening tools  100  may be simultaneously moved in the vertical direction primarily. 
     In contrast, in the first fastening tool disposing step, the n fastening tools  100  may be sequentially moved in the horizontal direction. In more detail, the movements of the plurality of fastening tools  100  in the circumferential direction A and the movements of the plurality of fastening tools  100  in the radial direction B may be independently performed by the first movement mechanisms  200  and the second movement mechanisms  300 , respectively. In this case, according to the exemplary form of the present disclosure, in the first fastening tool disposing step, the fastening tool  100  may be moved in the circumferential direction A, and then moved in the radial direction B. However, on the contrary, according to another exemplary form of the present disclosure, in the first fastening tool disposing step, the fastening tool  100  may be moved in the radial direction B, and then moved in the circumferential direction A. 
     Meanwhile, the method of operating the fastening apparatus according to the present disclosure may further include after the first storage step, a second workpiece disposing step of disposing a second workpiece including p fastening holes at one side of the fastening apparatus  10 , a second fastening tool disposing step of disposing each of the n fastening tools  100  above any one of the p fastening holes, and a second storage step of storing, in the control unit, positions of the n fastening tools  100  in the second fastening tool disposing step. In this case, p may be larger than n. 
     In addition, according to the present disclosure, in a case in which the first workpiece and the second workpiece are workpieces identical in type to each other, the information stored in the control unit in the first storage step may be removed from the control unit after the second storage step. That is, in the case in which the first workpiece and the second workpiece are the workpieces identical in type to each other, the information stored in the control unit in the first storage step may be replaced with the information stored in the control unit in the second storage step. Therefore, according to the present disclosure, when it is desired to change the information, which has been previously stored in the control unit in respect to the positions of the fastening holes formed in the workpiece, to new information, the second fastening tool disposing steps and the second storage steps are alternately performed, thereby easily changing the information on the positions of the fastening holes formed in the workpiece. Therefore, it is possible to shorten the time it takes to perform the teaching process of the fastening apparatus  10  for performing the fastening operation. 
     In contrast, according to the present disclosure, in a case in which the first workpiece and the second workpiece are workpieces different in type from each other, the information stored in the control unit in the first storage step and the information stored in the control unit in the second storage step may coexist in the control unit after the second storage step. Therefore, according to the present disclosure, the information on positions of fastening holes of various types of workpieces may be stored in the control unit, it is possible to perform the fastening operations on various types of workpieces using the single fastening apparatus. In particular, the fastening apparatus according to the present disclosure may independently perform not only the movement in the vertical direction, but also the movement in the circumferential direction and the movement in the radial direction, and as a result, the fastening apparatus may effectively perform the fastening operations on various types of workpieces. 
     Meanwhile, according to the present disclosure, the first fastening tool disposing step may further include moving the fastening tool  100  of the fastening apparatus  10  in the horizontal direction and then secondarily moving the fastening apparatus  10  in the vertical direction. Therefore, the first fastening tool disposing step may sequentially include (i) primarily moving the fastening apparatus  10  in the vertical direction, (ii) moving the fastening tool  100  in the horizontal direction, and (iii) secondarily moving the fastening apparatus  10  in the vertical direction. In more detail, the step (iii) may be the step of secondarily moving the fastening apparatus  10  in the vertically downward direction. In addition, the step (i) may be the step of primarily moving the fastening apparatus  10  in the vertical direction so that the fastening tool  100  of the fastening apparatus  10  and the fastening hole provided in the first workpiece are spaced apart from each other at a predetermined interval, and the step (iii) may be the step of secondarily moving the fastening apparatus  10  later in the vertically downward direction so that the fastening tool  100  of the fastening apparatus  10  is adjacent to the fastening hole to the extent that the fastening tool  100  may perform the fastening operation on the fastening hole provided in the first workpiece. For example, in the step (i), the vertical interval between the fastening tool  100  and the fastening hole may be about 5 mm. 
     Meanwhile, the contents described regarding the first fastening tool disposing step may also be equally applied to the second fastening tool disposing step. That is, according to the present disclosure, the second fastening tool disposing step may sequentially include (i) primarily moving the fastening apparatus  10  in the vertical direction, (ii) moving the fastening tool  100  in the horizontal direction, and (iii) secondarily moving the fastening apparatus  10  in the vertical direction. In more detail, the step (iii) may be the step of secondarily moving the fastening apparatus  10  in the vertically downward direction. In addition, the step (i) may be the step of primarily moving the fastening apparatus  10  in the vertical direction so that the fastening tool  100  of the fastening apparatus  10  and the fastening hole provided in the second workpiece are spaced apart from each other at a predetermined interval, and the step (iii) may be the step of secondarily moving the fastening apparatus  10  later in the vertically downward direction so that the fastening tool  100  of the fastening apparatus  10  is adjacent to the fastening hole to the extent that the fastening tool  100  may perform the fastening operation on the fastening hole provided in the first workpiece. For example, in the step (i), the vertical interval between the fastening tool  100  and the fastening hole may be about 5 mm. 
     Meanwhile, the method of operating the fastening apparatus according to the present disclosure may further include after the first storage step, a fastening performing step of performing the fastening operation on the m fastening holes provided in the first workpiece by loading the information stored in the control unit in the first storage step, using the n fastening tools  100 , and using fasteners such as nuts. In more detail, in the fastening performing step, the fastening apparatus  10  or the fastening tool  100  may be moved on the basis of the information stored in the first storage step in respect to the positions of the fastening holes, and then the fastening operation may be performed on the fastening hole by each of the fastening tools  100 . In this case, since the number of fastening holes is larger than the number of fastening tools as described above, the process of moving the fastening tools  100  to the fastening holes, on which the fastening operations have not been performed, may be additionally required after the first fastening operations of the fastening tools  100  are performed on the fastening holes. 
     In this case, according to the present disclosure, in the fastening performing step, when each of the n fastening tools  100  performs the fastening operation on any one of the m fastening holes provided in the first workpiece and then moves to another fastening hole, the movement time it takes for one of the n fastening tools to move may be equal to the movement time it takes for the other fastening tools to move. In this case, it is possible to remove difference in movement time between the fastening tools in accordance with movement distances of the fastening tools when the fastening tools move to other fastening holes after performing the fastening operation on some fastening holes. As a result, it is possible to minimize the time it takes to perform the fastening operation. For example, the movement time may be one second. 
       FIG.  5    is a perspective view illustrating an example of the display provided on the control unit of the fastening apparatus according to the present disclosure. 
     A process of manipulating the display in accordance with the method of operating the fastening apparatus according to the present disclosure will be described below with reference to  FIG.  5   . 
     According to the present disclosure, the first workpiece is selected, and then the type of the first workpiece is selected in ‘TYPE SELECTION’ on the display. In this case, in a case in which the type of the first workpiece is a type already stored in the control unit, for example, in a case in which the first workpiece is a new U oil pan, ‘NEW U OIL PAN’ is selected on the display. In contrast, in a case in which the type of the first workpiece is a type which is not stored in the control unit, a blank box is selected in ‘TYPE SELECTION. Hereinafter, the case in which the first workpiece is the ‘new U oil pan’ will be mainly described. 
     After the type of the first workpiece is selected in ‘TYPE SELECTION’ and the first workpiece is disposed at one side of the fastening apparatus, each of the plurality of fastening tools is positioned above any one of the plurality of fastening holes. In this case, the movement of the fastening tool may be performed as a user selects each column positioned below ‘STORE TARGET’ in  FIG.  5    and then directly inputs coordinates of the position, or the movement of the fastening tool may be performed as a person applies force directly to the fastening tool. In particular, the movement of the fastening apparatus in the vertical direction may be performed by adjusting the time for which ‘Z JOG +’ or ‘Z JOG −’ is pushed on the display illustrated in  FIG.  5   . 
     Thereafter, ‘ENTER DATA’ is selected to store the current position of the fastening tool, that is, the position of the fastening hole to be fastened later during the fastening process. In this case, the current position of the fastening tool may be stored after ‘#1’ is selected on the display. In this case, ‘#1’ means the fastening holes which constitute a ‘first group’ among the fastening holes of the first workpiece. Since the number of fastening holes is larger than the number of fastening tools as described above, the process of storing the positions of the fastening holes of the first workpiece needs to be performed several times. 
     Therefore, afterwards, the plurality of fastening tools is moved so that the plurality of fastening tools is positioned above the fastening holes above which the fastening tools have not been positioned in the previous step, among the plurality of fastening holes. Further, ‘ENTER DATE’ is selected again to store the current position of the fastening tool, that is, the position of the fastening hole to be fastened later during the fastening process. In this case, the current position of the fastening tool may be stored after ‘#2’ is selected on the display. In this case, ‘#2’ means the fastening holes which constitute a ‘second group’ among the fastening holes of the second workpiece. 
     The above-mentioned storage processes may be repeated in accordance with the number of fastening holes. For example, in the case in which the number of fastening tools is eight and the number of fastening holes is twenty-two, the above-mentioned processes may be repeated until ‘#3’ is selected and the current position of the fastening tool is stored. In addition, in a case in which the number of fastening tools is eight and even ‘#5’ may be selected as illustrated in  FIG.  5   , the positions of the fastening tool with respect to a total of forty fastening holes may be stored in the control unit. 
     The present disclosure has been described with reference to the limited exemplary forms and the drawings, but the present disclosure is not limited thereto. The described exemplary forms may be carried out in various forms by those skilled in the art to which the present disclosure pertains within the technical spirit of the present disclosure.