Bending and forming device, bending and forming method and computer program

Abstract

To bend and form a long member such that a dent does not occur after bending and forming.SOLUTION: A bending and forming device includes: a shape prediction unit which uses a pre-created prediction model to predict the shape in a case of bending and forming a long member so as to be in the target shape; and a conversion unit which converts the target shape into an alternative shape being a different shape when a dent part being an error exceeding a threshold relative to the target shape occurs in the predicted shape of the long member in a case of being bent and formed. The alternative shape is the shape in which the curvature at the time of bending and forming in a prescribed section containing the dent part is reduced relative to the target shape in the longitudinal direction of the long member, and the curvature at the time of bending and forming in a section other than the prescribed section is increased relative to the target shape. The shape prediction unit predicts the shape in a case of bending and forming the long member so as to be in the alternative shape converted by the conversion unit by using the prediction model.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bending apparatus, a bending method, and a computer program. [Background technology]

[0002] There is known an apparatus for bending a long member such as a pipe material (see, for example, Patent Document 1). Patent Document 1 describes a bending apparatus that bends a long member 180 degrees at an accurate position before bending. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-161670 A Summary of the Invention [Problem to be solved by the invention]

[0004] In bending, one of the forming defects is that the curvature after bending differs from the target curvature, and a dent with a curvature larger than the target curvature occurs. The bending device described in Patent Document 1 can bend at an accurate position, but does not take into consideration the dent that occurs after bending. In particular, when the member to be bent is a long member in which members of different thicknesses and materials are welded together, dents are likely to occur near the welded parts.

[0005] The present invention is intended to solve at least some of the above-mentioned problems, and has an object to bend a long member so that no dents are generated after bending. [Means for solving the problem]

[0006] The present invention is intended to solve at least a part of the above-mentioned problems, and can be realized in the following forms.

[0007] (1) According to one aspect of the present invention, there is provided a bending apparatus comprising: a shape prediction unit that predicts a shape of a long member when the long member is bent to a target shape using a prediction model created in advance; and a conversion unit that converts the target shape into an alternative shape that is a different shape when the predicted shape of the long member when the long member is bent has a dent that has an error of a threshold or more from the target shape, the alternative shape being a shape in which the curvature during bending in a predetermined section including the dent is smaller than the target shape in the longitudinal direction of the long member, and the curvature during bending in a section other than the predetermined section is larger than the target shape, and the shape prediction unit uses the prediction model to predict the shape of the long member when the long member is bent to the alternative shape converted by the conversion unit.

[0008] According to this configuration, when a dent occurs in the bent shape of the long member predicted by the shape prediction unit, the target shape is converted to an alternative shape. In the converted alternative shape, the curvature of the section where a dent occurs when the long member is bent is reduced, making it difficult for a dent to occur. Therefore, in this configuration, the long member is bent into a shape in which a dent does not occur after bending. Furthermore, in the alternative shape, the curvature of a section different from the section where the curvature is reduced is increased. Therefore, in this configuration, the alternative shape can be made closer to the target shape before conversion than when the curvature of only the section where the dent occurs is changed.

[0009] (2) In the bending forming apparatus of the above-mentioned aspect, the conversion unit may convert the target shape into the alternative shape so that the positional relationship between two specified points on the long member in the alternative shape is the same as the positional relationship between the two specified points on the long member in the target shape. According to this configuration, the target shape is converted into the alternative shape so that the positional relationship between the two predetermined points in each of the target shape and the alternative shape is the same. Therefore, for example, if the two predetermined points in the long member after bending are the locations to be fixed to another member, the converted alternative shape can also be used to fix the long member to the other member. In other words, the alternative shape of this configuration is converted into a shape in which the fixing positions of the other member match.

[0010] (3) In the bending device of the above aspect, the conversion unit may select, as the sections other than the predetermined section, the entire sections located on both sides of the predetermined section. According to this configuration, in the alternative shape, the section whose curvature is changed to be large is the entire section located on both sides of the predetermined section whose curvature is changed to be small. Therefore, the difference between the target shape and the alternative shape can be made smaller than when the section whose curvature is changed to be large is a section that is not adjacent to the predetermined section or a part of a section other than the predetermined section. Furthermore, the change in the curvature of the section other than the predetermined section whose curvature is changed to be large is suppressed.

[0011] (4) In the bending apparatus of the above aspect, the long member may be a welded pipe in which two types of metal pipe materials differing in at least one of thickness and material are welded together. In this configuration, for a welded pipe having a welded joint where two types of pipe materials are welded together, which is particularly prone to dents, the target shape is converted to an alternative shape, which effectively prevents dents from occurring in long members that are prone to dents.

[0012] (5) In the bending apparatus of the above aspect, the thickness of each of the two types of pipe material may be 0.6 mm or more and 3.0 mm or less, and the thickness ratio of the two types of pipe material may be 1 or more and 5 or less. According to this configuration, when bending a long member having a thickness of a pipe material in which dents are likely to occur and a ratio of the thicknesses of the two pipe materials among welded pipes in which two types of pipe materials are welded, the alternative shape is converted from the target shape, and thus it is possible to effectively prevent dents from occurring in the long member in which dents are likely to occur.

[0013] (6) In the bending apparatus of the above aspect, the thickness of each of the two types of pipe material may be 1.2 mm or more and 2.3 mm or less, and the thickness ratio of the two types of pipe material may be 1 or more and 2 or less. According to this configuration, when bending a long member having a thickness of a pipe material in which dents are particularly likely to occur and a ratio of the thicknesses of the two pipe materials among welded pipes in which two types of pipe materials are welded, the alternative shape is converted from the target shape, and thus it is possible to effectively prevent dents from occurring in the long member in which dents are particularly likely to occur.

[0014] (7) The bending apparatus of the above aspect may further include a bending section that bends the long member while feeding it in the feed direction. In this configuration, it is possible to use a conventional bending section to bend a long member without generating any dents after bending.

[0015] (8) The bending forming apparatus of the above aspect may further include an error calculation unit that calculates the error between the shape of the long member after bending by the bending forming unit and the shape of the long member when bent as predicted by the shape prediction unit, and a correction unit that corrects the prediction model using the error calculated by the error calculation unit. According to this configuration, the prediction model is corrected using the error between the shape of the long member after bending into an alternative shape free of dents and the shape of the long member when bent as predicted by the shape prediction unit. Therefore, the corrected prediction model can accurately predict the dents that will occur in the long member when bent into a target shape or an alternative shape. As a result, the accuracy of conversion to an alternative shape free of dents is improved.

[0016] The present invention can be realized in various forms, for example, in the form of a bending forming apparatus, a processing apparatus, and a system equipped with these apparatus, a bending forming method, a control method for these apparatus and systems, a computer program executed in these apparatus and systems, a server device for distributing the computer program, and a non-transitory storage medium on which the computer program is stored. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic block diagram of a bending system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a schematic top view of the molding apparatus. [Diagram 3] FIG. 2 is a schematic top view of a long member before bending. [Figure 4] FIG. 4 is a schematic top view of the long member after bending. [Diagram 5] FIG. 2 is a schematic enlarged view of a joint section including a dent. [Figure 6] FIG. 13 is an explanatory diagram of the CAE results of the inside of a long member when bent into a target shape. [Figure 7] 10 is an explanatory diagram showing the relationship between the curvature of a long member and the amount of depression of a depression portion. FIG. [Figure 8] 10 is an explanatory diagram showing a change in curvature according to a position in the longitudinal direction of a long member. FIG. [Figure 9] FIG. 13 is an explanatory diagram of the curvature of the joint section in a target shape and an alternative shape. [Figure 10] 13 is a flowchart of a conversion process from a target shape to an alternative shape by a conversion unit. [Figure 11] 11 is an explanatory diagram illustrating the change in curvature of a section of a long member. FIG. [Figure 12] 4 is a flowchart of the bending method of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] First Embodiment FIG. 1 is a schematic block diagram of a bending system (bending device) 100 according to one embodiment of the present invention. When bending a long member such as a pipe into a target shape, the bending system 100 of this embodiment uses a prediction model to predict the shape of the long member after bending. In this embodiment, if a dent occurs in the predicted shape, the target shape is converted into an alternative shape so that the dent does not occur after bending. The bending system 100 bends the long member into an alternative shape that does not have a dent, instead of the target shape.

[0019] As shown in FIG. 1, the bending system 100 includes a forming device (bending section) 80 that bends a long material while feeding the material in a feed direction, and a forming control device 50 that controls the forming device 80.

[0020] Fig. 2 is a schematic top view of the forming device 80. The forming device 80 bends the long material LG while feeding it along a feed direction DR1 from the left side to the right side of the figure. As shown in Fig. 2, the forming device 80 includes a support tool 82 disposed upstream in the feed direction DR1, and a bending tool 81 disposed downstream of the support tool 82 in the feed direction DR1. Note that the Cartesian coordinate system CS shown in Fig. 2 corresponds to the Cartesian coordinate system CS shown in Fig. 3 and subsequent figures.

[0021] The support tool 82 and the bending tool 81 are pressed against the long member LG to bend the long member LG. The support tool 82 has upstream rotating rollers RL1 and RL2 arranged to sandwich the long member LG in the feed direction DR1, and rotating rollers RL3 and RL4 arranged at positions different from the rotating rollers RL1 and RL2 on the downstream side along the feed direction DR1 and to sandwich the long member LG. The four rotating rollers RL1 to RL4 rotate around an axis parallel to the Z axis.

[0022] The bending tool 81 has rotating rollers RL5 and RL6 arranged to sandwich the long member LG, similar to the rotating rollers RL1 to RL4 of the support tool 82. The bending tool 81 is movable on the XY plane under the control of the forming control device 50. The bending tool 81 changes its relative position with respect to the support tool 82 on the XY plane. The amount of change in the relative position of the bending tool 81 is represented by the amount of movement D along the Y axis and the amount of rotation θ around an axis parallel to the Z axis on the XY plane. The sensor 21 provided in the forming control device 50 shown in FIG. 2 will be described later.

[0023] In the state shown in FIG. 2, the long member LG is bent and supported at three points: point P1 in contact with rotating roller RL2, point P2 in contact with rotating roller RL3, and point P3 in contact with rotating roller RL6.

[0024] The forming control device 50 shown in Fig. 1 includes a CPU (Central Processing Unit) 10, a sensor 21, a storage unit 22, a display unit 23, and an input unit 24. The forming control device 50 is configured, for example, with a personal computer. As shown in Fig. 2, the sensor 21 is a displacement sensor that detects an actual measurement value of the amount of displacement along the Y axis of an intermediate portion of the long member LG that is located between a support tool 82 and a bending tool 81 in the feed direction DR1. The sensor 21 of this embodiment detects the actual measurement value for each predetermined feed amount.

[0025] The storage unit 22 is composed of a hard disk drive (HDD: Hard Disk Drive) and the like. The storage unit 22 stores a prediction model for predicting the shape of the long member LG after bending, which changes according to the movement amount D and rotation amount θ of the bending tool 81 (FIG. 2) when the long member LG is bent by the forming device 80. The prediction model of this embodiment is created in advance based on the shape of the long member LG, such as the thickness, the material of the long member LG, and the measurement results of bending the long member LG multiple times with the movement amount D and the rotation amount θ changed. The prediction model is associated with the shape of the long member LG, such as the thickness, the material of the long member LG, the movement amount D and the rotation amount θ, and the curvature of the long member LG after bending. In addition, the prediction model of this embodiment is associated with the curvature of the long member LG after bending, and the displacement amount of the long member LG during bending detected between the support tool 82 and the bending tool 81 detected by the sensor 21. Therefore, the shape of the long member LG after bending is predicted by the prediction model based on the detection value of the sensor 21 and the shape (thickness) and material of the long member LG. Furthermore, the prediction model also predicts the amount of dent in the dented portion after bending.

[0026] The display unit 23 is a monitor capable of displaying various images, and displays various information in response to information transmitted from the CPU 10. For example, the display unit 23 displays the curvature of each part of the long member LG when bent using the prediction model, the detection value of the sensor 21, and the like. The input unit 24 is a user interface composed of a mouse and a keyboard that accepts various operations. For example, when predicting the shape of the long member LG when bent using the prediction model, the input unit 24 accepts various settings such as the shape and material of the long member LG, and the target shape after bending.

[0027] The CPU 10 executes a program stored in a read only memory (ROM) (not shown) by expanding the program in a random access memory (RAM). The CPU 10 functions as a prediction unit (shape prediction unit) 11, a conversion unit 12, a control unit 13 that controls each unit of the forming device 80, a measurement unit (error calculation unit) 14, and a correction unit 15. The prediction unit 11 uses a prediction model stored in the memory unit 22 to predict the shape of the long member LG when it is bent so as to have a target shape after bending.

[0028] When a dent occurs in the shape of the long member LG predicted by the prediction unit 11 when it is bent, the conversion unit 12 converts the target shape into an alternative shape that is different from the target shape. A dent is a part that has an error of a threshold or more from the target shape. In this embodiment, the conversion unit 12 regards a part that has a curvature of a predetermined value or less than the curvature of the target shape as a dent. The threshold value used to determine a dent is stored in the memory unit 22.

[0029] FIG. 3 is a schematic top view of the long member LG before bending. The long member LG shown in FIG. 3 is formed of the same material (STKM11A). The long member LG is a welded pipe in which a first pipe material MT1 and a second pipe material MT2 made of two types of metals with different pipe thicknesses are welded together. The pipe thickness of the first pipe material MT1 is 1.2 mm. The length L1 along the longitudinal direction of the first pipe material MT1 is 600 mm. The pipe thickness of the second pipe material MT2 is 2.3 mm. Therefore, in the two types of pipe materials, the first pipe material MT1 and the second pipe material MT2, the ratio of the thickness of the second pipe material MT2 to the first pipe material MT1 is 1.92 (=2.3 mm / 1.2 mm). The length L1 along the longitudinal direction of the second pipe material MT2 is 1500 mm. The pipe diameter φ (outer diameter) of the first pipe material MT1 and the second pipe material MT2 is 50.8 mm. During bending, the first tube material MT1 is bent by the bending tool 81 before the second tube material MT2.

[0030] FIG. 4 is a schematic top view of the long member LG after bending. In FIG. 4, a predicted shape of the long member LG when bent into a target shape is shown by a dashed line, and a predicted shape of the long member LG when bent into an alternative shape is shown by a solid line. The center line of the long member LG when bent into the alternative shape is shown by a dashed line. In FIG. 4, scales are shown along the X-axis and Y-axis directions. In FIG. 4, the long member LG is shown so that the first pipe material MT1 is located at the lower left and the second pipe material MT2 is located at the upper right, with a position Pa described later as the reference (the origin of the X-coordinate and the Y-coordinate).

[0031] In the long member LG shown in Fig. 4, a dent is included in a joint including a portion where the first pipe MT1 and the second pipe MT2 are welded. The conversion unit 12 of this embodiment converts the curvature during bending in the joint section PT2 including the dent in the longitudinal direction of the long member LG into an alternative shape that is smaller than the target shape. The conversion unit 12 further converts the curvature during bending in sections PT1 and PT3 other than the joint section PT2 to be larger than the target shape as the alternative shape. The lengths along the longitudinal direction of the sections PT1 to PT4 are 200 mm, 150 mm, 250 mm, and 200 mm, respectively.

[0032] 4 are connection positions where the long member LG is connected to another member after bending. The conversion unit 12 converts the target shape to the alternative shape so that the positional relationship of the connection positions Pa, Pb, Pc on the long member LG is the same when the target shape is converted to the alternative shape.

[0033] Fig. 5 is a schematic enlarged view of the joint section PT2 including the dent PD. Fig. 5 shows a schematic enlarged top view of the welded portion of the first pipe material MT1 and the second pipe material MT2 including the dent PD. The dent amount δ of the dent PD shown in Fig. 5 is calculated from the shape using a prediction model by the prediction unit 11.

[0034] Fig. 6 is an explanatory diagram of the CAE (Computer Aided Engineering) results of the inside of the long member LGa when it is bent into a target shape. The long member LGa shown in Fig. 6 is different from the long member LG shown in Figs. 3 to 5. The long member LGa is an example of a long member used to explain the relationship between the dent amount δ of the dent portion PD and the curvature.

[0035] Fig. 6(a) shows the CAE result of the entire long member LGa. Fig. 6(b) shows the CAE result of an enlarged region RG1 in Fig. 6(a). As shown in Fig. 6(b), the CAE result of the long member LGa is formed by connecting a plurality of discrete coordinates on the long member LGa. The conversion unit 12 of this embodiment calculates the curvature of the long member LGa by assuming that three consecutive discrete coordinate values ​​exist on an arc with the same radius of curvature.

[0036] Fig. 7 is an explanatory diagram showing the relationship between the curvature of the long member LGa and the dent amount δ of the dent portion PD. As shown in Fig. 7, using the radius of curvature r calculated from the three continuous discrete coordinates shown in Fig. 6, the length L of the arc, the dent amount δ, the difference a between the radius of curvature r and the dent amount δ, and the central angle α of the arc, the dent amount δ is expressed as in the following formula (1).

number

[0037] Fig. 8 is an explanatory diagram showing the change in curvature according to the longitudinal position of the long member LGa. The conversion unit 12 calculates and evaluates the amount of dent δ that exceeds the allowable value shown in Fig. 7 as a curvature. The conversion unit 12 converts the target shape into an alternative shape so that the amount of dent δ does not exceed the allowable value. In Fig. 8, the change in curvature near the welded portion between the first pipe material MT1 and the second pipe material MT2 is surrounded by a dashed line.

[0038] Fig. 9 is an explanatory diagram of the curvature of the joint section PT2 (Fig. 4) in the target shape and the alternative shape. Figs. 9(a) and (b) show the change in curvature with respect to the feed amount along the longitudinal direction of the long member LG. Fig. 9(a) shows the change in curvature Lc1 of the alternative shape in which the joint section PT2 does not have the recessed portion PD. Fig. 9(b) shows the change in curvature Lc2 of the target shape.

[0039] In the example shown in FIG. 9, the threshold value Th of the curvature of the joint section PT2 (curvature 0.58 m -1 ) is set. Therefore, the conversion unit 12 determines that a curvature exceeding the threshold value Th in the joint section PT2 is a dent section PD. When a dent section PD is present, the conversion unit 12 converts the target shape into an alternative shape by decreasing the curvature of the joint section PT2 and increasing the curvatures of sections PT1 and PT3 adjacent to the joint section PT2. Note that, if the target shape cannot be converted into an alternative shape even if the curvatures of sections PT1 and PT3 are increased, the curvature of section PT4 may be changed from the curvature of the target shape.

[0040] Fig. 10 is a flowchart of the conversion process from a target shape to an alternative shape by the conversion unit 12. In the conversion flow of Fig. 10, first, the conversion unit 12 determines whether or not a dent PD occurs in the long member LG when bending is performed by the prediction unit 11 using a prediction model (step S1). If it is determined that a dent PD does not occur (step S1: NO), conversion to an alternative shape is not performed and the conversion flow ends. In this case, the long member LG is bent into the target shape.

[0041] In the process of step S1, when it is determined that the dent portion PD occurs (step S1: YES), the conversion unit 12 reduces the curvature of the joint section PT2 where the dent portion PD occurs (step S2). A specific calculation method for reducing the curvature will be described later in the process of step S4.

[0042] The conversion unit 12 judges whether or not the positions of the connection positions Pa, Pb, and Pc with other members in the shape of the long member LG when the joint section PT2 is bent to reduce the curvature are within a predetermined error range with respect to the positions of the connection positions Pa, Pb, and Pc in the target shape (step S3). If it is judged that the positions of the connection positions Pa, Pb, and Pc are within the predetermined error range (step S3: YES), the processing of step S5 described later is performed. If it is judged that the positions of the connection positions Pa, Pb, and Pc are not within the predetermined error range (step S3: NO), the conversion unit 12 increases the curvature of the sections PT1 and PT3 other than the joint section PT2 with the reduced curvature (step S4). The predetermined error range is stored in advance in the storage unit 22 as a criterion used for judging the error of the connection positions Pa, Pb, and Pc. Steps S2 and S4 correspond to a conversion process.

[0043] Fig. 11 is an explanatory diagram when the curvature of the sections PT1a to PT3a of the long member LGb is changed. Fig. 11 shows a long member LGb different from the long member LG to explain a method of calculating the curvature of the alternative shape. Fig. 11 shows the long member LG after bending when the arc S (broken line) and straight lines Lrl and Lrr when the long member LGb is shaped into a target shape are converted into an alternative shape composed of arcs Sl, Sc, and Sr. Note that the connection positions with other members are Paa and Pba.

[0044] In the present embodiment, when changing from a target shape to an alternative shape, the conversion unit 12 selects the entire sections located on both sides of the joint section PT2a in which the dent portion PD occurs as sections in which the curvature during bending is made larger than that of the target shape. Specifically, among the arcs Sl, Sc, and Sr between the connection position Paa and the connection position Pba, the sections PT1a and PT3a other than the arc Sc of the joint section PT2a are selected. The arc Sc is an arc in which the dent portion PD does not occur after the conversion of the joint section PT2a in which the dent portion PD occurs. The arcs Sl and Sr are sections PT1a and PT3a adjacent to the joint section PT2a in which the dent portion PD does not occur. In addition, in the long member LGb shown in FIG. 11, the lengths of the arcs Sl, Sc, and Sr are the same in order to simplify the calculation.

[0045] In the long member LGb shown in Fig. 11, a dent PD occurs at the coordinate (Xr_c, Yr_c) of the joint, which is the midpoint of the long member LGb between the arc S and the straight lines Lrl and Lrr when bent into the target shape. In this case, with the connection positions Paa and Pba unchanged, the coordinate where the dent PD occurs changes to (Xrc_c, Yrc_c) on the transformed arc Sc where the curvature of the joint section PT2a has become smaller. The straight lines Lrl and Lrr have the same length.

[0046] Here, the radius of curvature R of the arc S and the angle A satisfy the following formula (2).

number

[0047] If the coordinates (Xr_c, Yr_c) of the dent PD in the target shape are defined as the origin (0, 0), the coordinates (Xr_l, Yr_l), (Xr_r, Yr_r) of the intersections between the arc S and the straight lines Lrl and Lrr are respectively expressed by the following relational expression (3).

number

[0048] The arc Sc of the joint section PT2a of the alternative shape is expressed by the following formula (4) using the radius of curvature Rc and the angle Ac.

number

[0049] Here, since the sum of angles Al, Ac, and Ar of arcs Sl, Sc, and Sr between joint section PT2a in the alternative shape and sections PT1a and PT3a must match angle A of arc S in the target shape before conversion, the following equation (5) holds for the angle.

number

[0050] Here, since the central angle Al of the arc Sl ​​in the alternative shape is the same as the central angle Ar of the arc Sr, the angles Al and Ar can be expressed as in the following formula (6) using the relationship in formula (5) above.

number

[0051] The circular arcs Sl and Sr are expressed by the following formula (7) using the angles Al and Ar.

number

[0052] Using the above relational expressions (2) to (7) and the coordinates (Xrc_c, Yrc_c) on the arc Sc of the alternative shape, the coordinates of both ends of each of the sections PT1a and PT3a are expressed by the following relational expression (8).

number

[0053] Here, when the X-coordinate Xrc_c of the arc Sc of the alternative shape coincides with the X-coordinate Xr_c of the dent PD of the target shape, the Y-coordinate Yrl_l of the left end point of the arc Sl ​​is located on the function Y1 expressed by the following formula (9). Alternatively, the Y-coordinate Yrr_r of the right end point of the arc Sr is located on the function Y2 expressed by the following formula (10).

[0054]

number

number

[0055] From the above equations (9) and (10), the following relational expression (11) is derived.

number

[0056] When the process of step S4 in FIG. 10 is performed, the prediction unit 11 predicts the shape of the long member LG when it is bent into the alternative shape after conversion (step S5). The process of step S5 corresponds to the second prediction step. The conversion unit 12 judges whether or not there is a dent in the predicted shape (step S6). The dents judged in the process of step S5 are for all sections PT1 to PT4 including the joint section PT2. If it is judged that there is a dent (step S6: YES), the process of step S2 and subsequent steps is performed. If it is judged that there is no dent (step S6: NO), the conversion unit 12 determines a shape without a dent as the alternative shape (step S7), and the conversion flow ends. That is, in this embodiment, if the dent PD is also generated in the alternative shape converted from the target shape, the conversion unit 12 repeats the conversion flow until the dent PD is no longer generated.

[0057] The control unit 13 shown in FIG. 1 controls the forming device 80 to bend the long member LG, which is the object of bending, into a target shape or an alternative shape. The measurement unit 14 acquires the detection value of the sensor 21. The measurement unit 14 calculates the error between the shape of the long member LG after bending by the forming device 80 and the shape of the long member LG when bent and predicted as the target shape or the alternative shape. Specifically, the measurement unit 14 predicts the actual measurement value of the long member LG after bending from the displacement amount of the long member LG during bending between the support tool 82 and the bending tool 81 acquired by the sensor 21 and the prediction model. The measurement unit 14 evaluates whether the actual measurement value is within a predetermined error range with respect to the target shape or the alternative shape. If the actual measurement value is not within the predetermined error range, the correction unit 15 corrects the prediction model stored in the memory unit 22 using the error of the actual measurement value. Specifically, the correction unit 15 corrects the correspondence between the movement amount D (FIG. 2) and rotation amount θ of the bending tool 81 and the curvature of the long member LG after bending. The predetermined error used for correcting the prediction model is stored in the storage unit 22.

[0058] Fig. 12 is a flowchart of the bending method of this embodiment. In the forming flow shown in Fig. 12, first, the prediction unit 11 predicts the shape of the long member LG when it is bent into a target shape using a prediction model (step S11). The processing of step S11 corresponds to a first prediction step. The conversion unit 12 performs the conversion processing shown in Fig. 10 (step S12). In the conversion processing, if a dent portion PD occurs in the predicted shape, the target shape is converted into an alternative shape in which the dent portion PD does not occur.

[0059] When the conversion process is performed (step S12), the control unit 13 controls the forming device 80 to bend the long member LG into a target shape or an alternative shape (step S13). The measurement unit 14 acquires the detection value of the sensor 21 during bending (step S14). The measurement unit 14 evaluates whether the actual measurement value after bending of the long member LG is within the error range for the target shape or the alternative shape from the acquired detection value (step S15). If it is evaluated that the actual measurement value is not within the error range (step S15: NO), the correction unit 15 corrects the prediction model stored in the storage unit 22 using the error of the actual measurement value (step S16), and the processes from step S12 onwards are repeated. If it is evaluated that the actual measurement value is within the error range (step S15: YES), the forming flow ends.

[0060] As described above, the prediction unit 11 of this embodiment predicts the shape of the long member LG when it is bent using the prediction model stored in the storage unit 22 so as to have a target shape after bending. When a dent PD occurs in the shape of the long member LG when it is bent as predicted by the prediction unit 11, the conversion unit 12 converts the target shape into an alternative shape that is a shape different from the target shape. The conversion unit 12 converts the curvature of the long member LG at the time of bending in the joint section PT2 (FIG. 4) including the dent PD in the longitudinal direction of the long member LG into an alternative shape that is smaller than the target shape. The conversion unit 12 further increases the curvature of the long member LG at the time of bending in sections PT1 and PT3 other than the joint section PT2 as the alternative shape. In this embodiment, when a dent PD occurs in the shape of the long member LG when it is bent as predicted by the prediction unit 11, the target shape is converted into the alternative shape. In the converted alternative shape, the curvature of the joint section PT2 where the dent section PD occurs when the long member LG is bent is reduced, making it difficult for the dent section PD to occur. Therefore, in this embodiment, the long member LG is bent into a shape where the dent section PD does not occur after bending. Furthermore, in the alternative shape, the curvatures of sections PT1 and PT3 different from the joint section PT2, which has a smaller curvature, are increased. Therefore, in this embodiment, the alternative shape can be made closer to the target shape before conversion, compared to the case where the curvature of only the joint section PT2 where the dent section PD occurs is changed.

[0061] Furthermore, the conversion unit 12 of this embodiment converts the target shape into the alternative shape so that the positional relationship of the connection positions Pa, Pb, and Pc on the long member LG is the same when the target shape is converted into the alternative shape. In this embodiment, the target shape is converted into the alternative shape so that the positional relationship of two predetermined points in each of the target shape and the alternative shape is the same. Therefore, the positions Pa, Pb, and Pc (FIG. 4), which are the connection positions with other members in the long member LG after bending, are the same as the connection positions of the other members in the alternative shape after conversion. That is, the alternative shape of this embodiment is converted into a shape in which the connection positions of the other members match.

[0062] In addition, when changing from the target shape to the alternative shape, the conversion unit 12 of this embodiment selects the entire sections located on both sides of the joint section PT2a (FIG. 11) where the dent portion PD occurs as the section in which the curvature during bending is made larger than that of the target shape. Specifically, among the arcs Sl, Sc, and Sr between the connection position Paa and the connection position Pba, the sections PT1a and PT3a other than the arc Sc of the joint section PT2a are selected. In this embodiment, the sections in which the curvature is converted to be larger in the alternative shape are the sections PT1a and PT3a, which are the entire sections located on both sides of the joint section PT2a in which the curvature is converted to be smaller. Therefore, the difference in shape between the target shape and the alternative shape can be made smaller compared to the case where the sections PT1a and PT3a in which the curvature is converted to be larger are sections not adjacent to the joint section PT2a or parts of sections other than the joint section PT2a. Furthermore, the change in the curvature of the sections PT1a and PT3a other than the joint section PT2a in which the curvature is converted to be larger is suppressed.

[0063] In addition, the long member LG shown in Fig. 3 of this embodiment is formed of the same material (STKM11A). Moreover, the long member LG is a welded pipe in which a first pipe material MT1 and a second pipe material MT2 made of two types of metals with different pipe thicknesses are welded together. In this embodiment, for a welded pipe having a welded portion where two types of pipe materials are welded together, which is particularly susceptible to the occurrence of a dent portion PD, an alternative shape is converted from the target shape. Therefore, the occurrence of a dent portion PD in the long member LG in which the dent portion PD is susceptible to occurrence can be effectively suppressed.

[0064] In addition, the pipe thickness of the first pipe material MT1 in this embodiment is 1.2 mm. The length L1 along the longitudinal direction of the first pipe material MT1 is 600 mm. The pipe thickness of the second pipe material MT2 is 2.3 mm. Therefore, in the two types of pipe materials, the first pipe material MT1 and the second pipe material MT2, the ratio of the thickness of the second pipe material MT2 to the first pipe material MT1 is 1.92. In this embodiment, when bending a long member LG of a welded pipe in which the first pipe material MT1 and the second pipe material MT2 are welded, in which the thickness of the pipe material in which the dent portion PD is likely to occur and the ratio of the thickness of the two types of pipe materials, the alternative shape is converted from the target shape. Therefore, the occurrence of the dent portion PD in the long member LG in which the dent portion PD is likely to occur can be effectively suppressed.

[0065] Moreover, the forming device 80 of this embodiment bends the long member LG while feeding it in the feed direction DR1. Therefore, in this embodiment, it is possible to use a conventional forming device 80 to bend the long member LG in which no dents PD are generated after bending.

[0066] In addition, the measurement unit 14 of this embodiment calculates the error between the shape of the long member LG after bending by the forming device 80 and the shape of the long member LG when bent and formed as predicted as the target shape or the alternative shape. When the actual measurement value after bending does not fall within a predetermined error range, the correction unit 15 corrects the prediction model stored in the storage unit 22 using the error of the actual measurement value. In this embodiment, the prediction model is corrected using the error between the shape of the long member LG after bending and formed into an alternative shape in which the dent portion PD does not occur and the shape of the long member LG when bent and formed as predicted by the prediction unit 11. Therefore, the corrected prediction model can accurately predict the dent portion PD that occurs in the long member LG when bent and formed into the target shape or the alternative shape. As a result, the accuracy of conversion to the alternative shape in which the dent portion PD does not occur is improved.

[0067] <Modifications of the embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the present invention, for example, the following modifications are possible: In the above-described embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware.

[0068] <Variation 1> In the above embodiment, the bending system 100, which is an example of a bending device, has been described. However, when it is predicted that a dent PD will occur in the long member LG when the long member LG is bent into a target shape using the prediction model, the bending device can deform within a range of converting the target shape into an alternative shape. For example, the bending device may not include the forming device 80, the sensor 21, the memory unit 22, the display unit 23, and the input unit 24, and may not function as the control unit 13, the measurement unit 14, and the correction unit 15. The bending device may only convert the target shape into an alternative shape and may not actually bend the long member LG. The prediction unit 11 may obtain a prediction model from another device through communication without using the prediction model stored in the memory unit 22. The bending device may not include the display unit 23 and the input unit 24, and may obtain information required for converting the alternative shape from another device through communication. The bending device may not include the sensor 21 and the measurement unit 14, and may not measure the actual value of the shape of the long member LG after bending. Furthermore, the bending apparatus does not need to correct the prediction model by the correcting unit 15.

[0069] In the above embodiment, the bending of the long member LG in which the first pipe material MT1 and the second pipe material MT2 are welded has been described, but the member to be bent can be deformed. The member to be bent may be formed of one type of pipe material without being welded, or may be a plate material or the like. In the long member LG in the above embodiment, the material of the first pipe material MT1 and the material of the second pipe material MT2 are the same, but in other long members, the materials of the two types of pipe materials to be welded may be different. When a long member is formed by welding two types of metal materials that are different in at least one of the thickness and the material, the thickness of each of the two types of pipe materials is preferably 0.6 mm or more and 3.0 mm or less. Furthermore, the thickness of each of the two types of pipe materials is preferably 1.2 mm or more and 2.3 mm or less. Moreover, the ratio of the thicknesses of the two types of pipe materials is preferably 1 to 5, and more preferably 1 to 2.

[0070] The long member LG in this embodiment refers to a member having a length of a section where the curvature in the alternative shape is smaller than that of the target shape due to the occurrence of the dent portion PD, and a section where the curvature is larger in the other sections. In addition, the connection positions Pa, Pb, Pc, etc. do not necessarily have to be set in advance on the long member LG. When the connection positions are not set, for example, the conversion unit 12 may set three sections divided by any length centered on the dent portion PD as a section including the dent portion PD where the curvature is smaller and two adjacent sections where the curvature is larger. In the above embodiment, as shown in FIG. 4, the alternative shape is converted so that the positional relationship between the two points, the connection position Pa and the connection position Pb, is the same before and after the conversion from the target shape to the alternative shape. However, the number of connection positions where the positional relationship is the same before and after the conversion may not be two points, but may be, for example, three or four points.

[0071] <Variation 2> The forming device 80 in the above embodiment bends the long member LG by three-point bending using the bending tool 81 and the support tool 82 while feeding the long member LG in the feed direction DR1. However, a well-known bending device can be applied as the forming device 80. The forming device 80 does not have to bend the long member LG while feeding it in the feed direction DR1. The forming device 80 may bend the long member LG by a method other than three-point bending.

[0072] Although the sensor 21 in the above embodiment detects the amount of displacement of the long member LG between the support tool 82 and the bending tool 81, the amount of displacement detected by the sensor 21 can be changed. For example, the sensor 21 may detect the amount of displacement of the long member LG after it has been bent by the bending tool 81. The sensor 21 may detect two amounts of displacement, before and after it has been bent by the bending tool 81. The correction unit 15 may correct the prediction model in accordance with the detection value of the sensor 21.

[0073] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0074] The present invention can also be realized in the following forms. [Application example 1] A bending forming apparatus, a shape prediction unit that predicts a shape of the long member when the long member is bent into a target shape by using a prediction model created in advance; a conversion unit that converts the target shape into an alternative shape that is different when a dent portion that is an error of a threshold value or more occurs in the shape of the long member when the predicted bending is performed; Equipped with the alternative shape is a shape in which a curvature during bending in a predetermined section including the recess in the longitudinal direction of the elongated member is made smaller than the target shape, and a curvature during bending in a section other than the predetermined section is made larger than the target shape, A bending apparatus, wherein the shape prediction unit uses the prediction model to predict the shape of the long member when bent to obtain the alternative shape converted by the conversion unit. [Application example 2] The bending apparatus according to Application Example 1, A bending forming device in which the conversion unit converts the target shape to the alternative shape so that the positional relationship between two specified points on the long member in the alternative shape is the same as the positional relationship between the two specified points on the long member in the target shape. [Application example 3] The bending apparatus according to Application Example 1 or Application Example 2, A bending forming apparatus, wherein the conversion unit selects the entire sections located on both sides of the specified section as sections other than the specified section. [Application example 4] The bending apparatus according to any one of Application Examples 1 to 3, The bending apparatus, wherein the long member is a welded pipe formed by welding two types of metal pipe material that differ in at least one of thickness and material. [Application example 5] The bending apparatus according to any one of Application Examples 1 to 4, The thickness of each of the two types of pipe materials is 0.6 mm or more and 3.0 mm or less; A bending forming apparatus, wherein the ratio of the thicknesses of the two types of pipe materials is 1 or more and 5 or less. [Application Example 6] The bending apparatus according to any one of Application Examples 1 to 5, The thickness of each of the two types of pipe materials is 1.2 mm or more and 2.3 mm or less; A bending forming apparatus, wherein the ratio of the thicknesses of the two types of pipe materials is 1 or more and 2 or less. [Application Example 7] The bending apparatus according to any one of Application Examples 1 to 6, further comprising: A bending device comprising a bending section that bends the long member while feeding the long member in a feed direction. [Application Example 8] The bending apparatus according to any one of Application Examples 1 to 7, further comprising: an error calculation unit that calculates an error between a shape of the long member after bending by the bending unit and a shape of the long member when bent as predicted by the shape prediction unit; a correction unit that corrects the prediction model by using the error calculated by the error calculation unit; A bending apparatus comprising: [Application Example 9] A bending method, comprising: A step of predicting a shape of the elongated member when the elongated member is bent into a target shape using a prediction model created in advance; When a dent portion that is an error of a threshold value or more from the target shape occurs in the predicted shape of the elongated member when the elongated member is bent, converting the target shape into an alternative shape that is a different shape; predicting a shape of the elongated member when bent into the transformed alternative shape using the predictive model; Run A bending method, in which the alternative shape is a shape in which the curvature during bending in a specified section including the recess in the longitudinal direction of the elongated member is made smaller than the target shape, and the curvature during bending in sections other than the specified section is made larger than the target shape. [Example 10] A computer program comprising: A shape prediction function that predicts the shape of a long member when it is bent into a target shape using a prediction model created in advance; a conversion function for converting the target shape into an alternative shape that is different when a dent portion that is an error of a threshold value or more occurs in the shape of the long member when the predicted bending is performed; on the computer, the alternative shape is a shape in which a curvature during bending in a predetermined section including the recess in the longitudinal direction of the elongated member is made smaller than the target shape, and a curvature during bending in a section other than the predetermined section is made larger than the target shape, The shape prediction function is a computer program that uses the prediction model to predict the shape of the long member when bent to obtain the alternative shape converted by the conversion function. [Explanation of symbols]

[0075] 11...Prediction unit (shape prediction unit) 12...Conversion section 13...Control section 14...Measuring section (error calculation section) 15...Compensation section 21…Sensor 22...Storage section 23...Display section 24...Input section 50...Molding control device 80...Forming device (bending section) 81…Bending tool 82...Support Tools 100...Forming system (bending device) 110…CPU CS...Cartesian coordinate system DR1...Feed direction LG, LGa, LGb...Long members MT1…1st pipe material MT2…Second pipe material PD…dent

Claims

1. A bending forming apparatus, a shape prediction unit that predicts a shape of the long member when the long member is bent into a target shape by using a prediction model created in advance; a conversion unit that converts the target shape into an alternative shape that is different when a dent portion that is an error of a threshold value or more occurs in the predicted shape of the elongated member after bending is performed; Equipped with the alternative shape is a shape in which a curvature during bending in a predetermined section including the recess in the longitudinal direction of the elongated member is made smaller than the target shape, and a curvature during bending in a section other than the predetermined section is made larger than the target shape, A bending apparatus, wherein the shape prediction unit uses the prediction model to predict the shape of the long member when bent to obtain the alternative shape converted by the conversion unit.

2. The bending apparatus according to claim 1, A bending forming apparatus in which the conversion unit converts the target shape into the alternative shape so that the positional relationship between two specified points on the elongated member in the alternative shape is the same as the positional relationship between the two specified points on the elongated member in the target shape.

3. The bending apparatus according to claim 2, A bending forming apparatus, wherein the conversion unit selects the entire sections located on both sides of the specified section as sections other than the specified section.

4. The bending apparatus according to claim 3, A bending apparatus, wherein the long member is a welded pipe formed by welding two kinds of metal pipe materials which differ in at least one of thickness and material.

5. The bending apparatus according to claim 4, The thickness of each of the two types of pipe materials is 0.6 mm or more and 3.0 mm or less, A bending forming apparatus, wherein the ratio of the thicknesses of the two types of pipe materials is 1 or more and 5 or less.

6. The bending apparatus according to claim 5, The thickness of each of the two types of pipe materials is 1.2 mm or more and 2.3 mm or less, A bending forming apparatus, wherein the ratio of the thicknesses of the two types of pipe materials is 1 or more and 2 or less.

7. The bending apparatus according to any one of claims 1 to 6, further comprising: A bending device comprising a bending section that bends the long member while feeding the long member in a feed direction.

8. The bending apparatus according to claim 7, further comprising: an error calculation unit that calculates an error between a shape of the long member after bending by the bending unit and a shape of the long member when bent as predicted by the shape prediction unit; a correction unit that corrects the prediction model by using the error calculated by the error calculation unit; A bending apparatus comprising:

9. A bending method, comprising: a first prediction step of predicting a shape of the elongated member when the elongated member is bent into a target shape by using a prediction model created in advance; a conversion step of converting the target shape into an alternative shape that is different when a dent portion that is an error of a threshold value or more occurs in the predicted shape of the elongated member after bending is performed; a second prediction step of predicting a shape of the elongated member when the elongated member is bent to obtain the converted alternative shape by using the prediction model; Run A bending method, in which the alternative shape is a shape in which the curvature during bending in a specified section including the recess in the longitudinal direction of the elongated member is made smaller than the target shape, and the curvature during bending in sections other than the specified section is made larger than the target shape.

10. A computer program comprising: A shape prediction function that predicts the shape of a long member when it is bent into a target shape using a prediction model created in advance; a conversion function for converting the target shape into an alternative shape that is different when a dent portion that is an error of a threshold value or more occurs in the shape of the long member when the predicted bending is performed; on the computer, the alternative shape is a shape in which a curvature during bending in a predetermined section including the recess in the longitudinal direction of the elongated member is made smaller than the target shape, and a curvature during bending in a section other than the predetermined section is made larger than the target shape, The shape prediction function is a computer program that uses the prediction model to predict the shape of the long member when bent to obtain the alternative shape converted by the conversion function.

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