Correction device control device, correction device, and correction device control method

Abstract

To remove a curl, which is a residual strain of a workpiece, by suppressing accumulated fatigue.SOLUTION: A control unit (20) for a correction device (1) having at least two correction parts for applying a load includes a measurement part (23) that measures measurement displacement magnitude when a measurement load is applied to a workpiece (40) wound like a roll, and a determination part (25) that determines a correction load or correction displacement magnitude for the workpiece, on the basis of the material property (31) of the workpiece, the measurement load and the measurement displacement magnitude. The determination part considers the material property on the basis of a stress strain diagram.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for an orthodontic appliance and an orthodontic appliance. [Background technology]

[0002] Produced steel sheets or wires are distributed in a rolled state. Therefore, in order to use the steel sheets or wires in production as workpieces, they need to be converted from the rolled state into flat plate material or straight wire material. Specifically, the rolled workpieces are straightened by applying external force with multiple rollers to remove the curling that occurred when they were wound into a roll.

[0003] In Patent Document 1, when a ribbon wound on a bobbin is used while being unwound, the unwound ribbon develops a curl in the thickness direction and a curve in the width direction of the ribbon. To remove this curl, multiple rollers are provided, and the curl remaining after being straightened by the first roller is measured and fed back to the position of the second roller repeatedly to straighten the curl. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-196037 Summary of the Invention [Problem to be solved by the invention]

[0005] When an external force is applied to a workpiece, it undergoes elastic or plastic deformation according to the stress-strain diagram (stress-strain characteristics). In the case of elastic deformation, when the external force is removed, only the original residual strain remains, whereas in the case of plastic deformation, even after the external force is removed, the original residual strain plus a strain corresponding to the applied external force (stress) remains as residual strain.

[0006] When a workpiece is wound into a roll, residual strain occurs as a curl, and removing this residual strain results in a component that is free of curls. The amount of residual strain varies depending on the position at which the workpiece is wound into a roll (the winding radius and the winding position on the bobbin, etc.).

[0007] As is clear from the stress-strain diagram, when deformation is performed with a large stress in the plastic region, the variation in the residual strain remaining after the load is removed tends to be smaller than the variation in the residual strain before processing.

[0008] Therefore, in the past, a large stress in one direction was applied to the workpiece to distort it significantly, absorbing the variation, and then a stress in the opposite direction was applied to remove the residual strain. This process was repeated while gradually reducing the stress, gradually reducing the residual strain.

[0009] When a large stress is applied to a workpiece all at once, lattice defects and cracks develop inside the workpiece. Therefore, when the residual strain is removed, the workpiece accumulates fatigue compared to before processing. This fatigue makes the workpiece more susceptible to fatigue fracture. Furthermore, the stress-strain characteristics vary depending on the lot or position of the workpiece.

[0010] Therefore, one aspect of the present invention aims to suppress fatigue that accumulates in a workpiece and to properly straighten the workpiece. [Means for solving the problem]

[0011] In order to solve the above problems, a control device according to one embodiment of the present invention is a control device for a straightening device having at least two straightening units that apply loads, and includes a characteristic acquisition unit that acquires the stress-strain characteristics of a rolled workpiece, a measurement unit that measures a first load or a first displacement amount during the period when a load is being applied to the workpiece by a first straightening unit, and a determination unit that determines a second load or a second displacement amount to be applied to the workpiece by a second straightening unit located downstream of the first straightening unit based on the stress-strain characteristics, the first load, and the first displacement amount.

[0012] According to the above configuration, the second load or the second displacement amount is determined based on the actually applied first load, the first displacement amount, and the stress-strain characteristics, thereby making it possible to perform appropriate straightening according to the workpiece. This avoids the application of an excessive load, thereby suppressing the accumulation of excessive fatigue and straightening the workpiece into a desired shape.

[0013] The device may further include a correction unit that corrects the stress-strain characteristic based on the first load and the first displacement amount, and the determination unit may determine the second load or the second displacement amount based on the corrected stress-strain characteristic.

[0014] According to the above configuration, the stress-strain characteristic can be corrected, and the determination unit can determine the corrective load or the corrective displacement amount with higher accuracy based on the corrected stress-strain characteristic.

[0015] The first load may be less than a load that causes plastic deformation of the workpiece, and the corrector may correct characteristics of an elastic region in the stress-strain characteristics.

[0016] According to the above configuration, when the first load is less than the load that causes plastic deformation of the workpiece, the first load is a load in the elastic region in the stress-strain characteristics, and therefore the characteristics of the elastic region in the stress-strain characteristics can be corrected to match the first load and the first displacement amount, which are the actual measured values.

[0017] The correction unit may correct the characteristics of the plastic region so that a predetermined yield stress or proof stress of the workpiece does not change.

[0018] According to the above configuration, by correcting the characteristics in the elastic region of the stress-strain characteristics, the characteristics in the plastic region can also be corrected.

[0019] The first load may be equal to or greater than a load that causes plastic deformation of the workpiece, and the corrector may correct characteristics of a plastic region in the stress-strain characteristics.

[0020] According to the above configuration, when the first load is equal to or greater than the load that causes plastic deformation of the workpiece, the first load is a load in the plastic region in the stress-strain characteristics, and therefore the characteristics of the plastic region in the stress-strain characteristics can be corrected to match the first load and the first displacement amount, which are the actual measured values.

[0021] The apparatus may further include a state acquisition unit that acquires the state of the workpiece before processing, and the correction unit may correct the stress-strain characteristics based on the state, the first load, and the first displacement amount.

[0022] According to the above-described configuration, the stress-strain characteristics can be corrected using the state before processing, particularly the residual strain, and as a result, the stress-strain characteristics can be corrected to an appropriate value.

[0023] The condition may be at least one of a residual strain in the workpiece, a curvature of the workpiece in the longitudinal direction, and a payout position of the workpiece.

[0024] According to the above configuration, the residual strain, which is a state of the workpiece, can be directly acquired, or the residual strain can be indirectly acquired from the curvature of the workpiece, the feed position of the workpiece, etc. This makes it possible to correct the stress-strain characteristics and prevent the application of excessive load, thereby suppressing the accumulation of excessive fatigue.

[0025] The correction unit may correct the elastic modulus, plastic modulus, yield stress, or proof stress of the workpiece in the stress-strain characteristics.

[0026] The determination unit may determine the second load or the second displacement amount so that a residual strain in the workpiece when the second load is released has a desired value.

[0027] According to the above configuration, the second load or the second displacement amount can be determined so that the residual strain in the workpiece has a desired value.

[0028] The second load may be equal to or greater than a load that causes plastic deformation of the workpiece.

[0029] According to the above configuration, the workpiece can be plastically deformed by the second load. This plastic deformation caused by the second load can correct the stress-strain characteristics of the plastic region or can process the residual strain of the workpiece to a desired residual strain.

[0030] The straightening device may include a third straightening unit located on the opposite side of the workpiece from the second straightening unit and located after the second straightening unit, the measuring unit measures the second load or the second displacement amount during a period in which the second straightening unit applies a load to the workpiece, and the determining unit determines the third load or the third displacement amount applied to the workpiece by the third straightening unit based on the corrected stress-strain characteristics, the second load, and the second displacement amount.

[0031] According to the above configuration, the third correcting section can apply a load opposite to the load that can be applied by the second correcting section, thereby removing residual strain in the workpiece.

[0032] The first correcting unit and the second correcting unit may be located on the same side of the workpiece.

[0033] A correction device according to one aspect of the present invention includes the control device.

[0034] A control method according to one embodiment of the present invention is a control method for a straightening device having at least two straightening units that apply loads, and includes a characteristic acquisition step of acquiring the stress-strain characteristics of a rolled workpiece, a measurement step of measuring a first load or a first displacement amount during a period in which a load is applied to the workpiece by a first straightening unit, and a determination step of determining a second load or a second displacement amount to be applied to the workpiece by a second straightening unit downstream of the first straightening unit based on the stress-strain characteristics, the first load, and the first displacement amount. [Effects of the Invention]

[0035] According to one aspect of the present invention, fatigue accumulated in a workpiece can be suppressed and the workpiece can be appropriately straightened. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a block diagram showing the configuration of a main part of a correction device according to a first embodiment. [Figure 2] FIG. 1 is a model diagram showing an outline of a correction device according to a first embodiment. [Figure 3] 4 is a flowchart showing the flow of operations of the correction device according to the first embodiment. [Figure 4] FIG. 3 is a data flow diagram in the control device according to the first embodiment. [Figure 5] FIG. 1 is a model diagram illustrating a method for correcting material properties using a stress-strain diagram. [Figure 6] FIG. 10 is a model diagram for deriving a third load or a third displacement from corrected material properties using a stress-strain diagram. [Figure 7] FIG. 10 is a model diagram for calculating the amount of deformation caused by a guide roller. [Figure 8] FIG. 10 is a side view of a model diagram showing an outline of a correction device according to a second embodiment. [Figure 9] FIG. 10 is a top view of a model diagram showing an outline of a correction device according to a second embodiment. [Figure 10] FIG. 10 is a model diagram showing an outline of a correction device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0037] [Embodiment 1] Hereinafter, an embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0038] §1. Application Examples 2 is a model diagram showing an overview of the straightening device 1 according to the first embodiment. The straightening device 1 is an apparatus that straightens the workpiece 40 using a plurality of rollers while unwinding the workpiece 40 wound in a roll from a supply unit 12 and feeding it in the X-axis direction using a feed mechanism 11. The axis of the workpiece 40 wound in a roll is parallel to the Y-axis. The vertically upward direction is defined as the Z-axis.

[0039] The unwound workpiece 40 has a tendency to wind around the roll, and this tendency remains in the workpiece as residual strain. A downward external force is applied to the workpiece 40 by the guide rollers 16a to 16d, and an upward external force is applied by the rollers of the first straightening section (straightening section) 13, the second straightening section (straightening section) 14, and the third straightening section (straightening section) 15, thereby repeatedly applying a load to the workpiece 40 to eliminate the residual stress.

[0040] Here, the first straightening unit 13, the second straightening unit 14, and the third straightening unit 15 are equipped with a movement mechanism, which allows the position of each roller to be adjusted. In addition, the first straightening unit 13, the second straightening unit 14, and the third straightening unit 15 are each equipped with a load cell, which allows the load applied by the roller to be measured. Therefore, the load and displacement amount for each roller can be determined, and the stress and strain applied by the roller to the workpiece 40 can be obtained.

[0041] Therefore, by dynamically correcting the stress-strain diagram (stress-strain characteristics) of the workpiece 40 based on the measured stress and strain, the third straightening unit 15 can straighten the workpiece 40 with an optimal load. This prevents straightening with an excessive load and suppresses the accumulation of fatigue in the workpiece 40.

[0042] §2. Configuration example FIG. 1 is a block diagram showing the configuration of the main parts of the correction device 1 according to the first embodiment.

[0043] (Configuration of orthodontic device 1) The straightening device 1 includes a feed mechanism 11, a supply unit 12, a first straightening unit (first straightening unit) 13, a second straightening unit (first straightening unit, second straightening unit) 14, a third straightening unit (second straightening unit, third straightening unit) 15, guide rollers 16a to 16d, and a control device 20.

[0044] The feed mechanism 11 draws out (feeds out) the workpiece 40 so that a tension that does not impair the mechanical strength of the workpiece 40 is applied to the workpiece 40. The feed mechanism 11 may be any mechanism that can draw out the workpiece 40. For example, the feed mechanism 11 may be a mechanism that comprises feed rollers that sandwich the workpiece 40 from above and below, and actively rotates the feed rollers to feed the workpiece 40.

[0045] The supply unit 12 passively pays out and supplies the workpiece 40 wound in a roll shape by the feed mechanism 11. The workpiece 40 may be a wide sheet-like steel plate or a wire rod with a substantially circular cross section. The workpiece is paid out from the supply unit 12 while retaining the curling tendency it had when wound in a roll shape, as shown in FIG. 2.

[0046] The guide rollers 16a to 16d are rollers that are fixed in position and rotate passively, and are provided along the X-axis.

[0047] The first straightening unit 13 is a movable adjustment mechanism made up of a passively rotating first straightening roller 131, a first load cell 132, and a first moving mechanism 133. The first moving mechanism 133 moves the position of the first straightening roller 131 in the Z-axis direction, thereby applying a load to the workpiece 40. At this time, the first load cell 132 can measure the load applied to the workpiece 40.

[0048] The second straightening unit 14 is a movable adjustment mechanism made up of a passively rotating second straightening roller 141, a second load cell 142, and a second movement mechanism 143. The second movement mechanism 143 moves the position of the second straightening roller 141 in the Z-axis direction, thereby applying a load to the workpiece 40 and straightening the workpiece 40. At this time, the second load cell 142 can measure the load applied to the workpiece 40.

[0049] The third straightening unit 15 is a movable adjustment mechanism made up of a passively rotating third straightening roller 151, a third load cell 152, and a third movement mechanism 153. The third movement mechanism 153 moves the position of the third straightening roller 151 in the Z-axis direction, thereby applying a load to the workpiece 40 and straightening the workpiece 40. At this time, the third load cell 152 can measure the load applied to the workpiece 40.

[0050] The first straightening roller 131, the second straightening roller 141, and the third straightening roller 151 are positioned on the opposite side of the guide rollers 16a to 16d across the workpiece 40. The straightening device 1 straightens the workpiece 40 by applying a load to the workpiece 40 sandwiched between the first straightening roller 131, the second straightening roller 141, and the third straightening roller 151 and the guide rollers 16a to 16d.

[0051] In this embodiment, to simplify the model, the guide rollers 16a to 16d are not movable and the load cannot be changed, but a load cell and a movement mechanism may be provided, as in the first correction unit 13, the second correction unit 14, and the third correction unit 15. In this case, the load can be measured by the guide rollers 16a to 16d, and the position of the rollers in the Z direction can be changed by the movement mechanism, so that the desired residual strain can be achieved even with a small number of rollers.

[0052] (Processing flow of orthodontic device 1) The workpiece 40 is first processed by the first straightening unit 13. The first straightening unit 13 applies stress to the workpiece 40 by pressing the workpiece 40 against the guide rollers 16a and 16b.

[0053] The workpiece 40 is moved to the next processing position by the feed mechanism 11 and processed by the guide rollers 16b. The guide rollers 16b apply stress to the workpiece 40 by pressing the workpiece 40 against the first straightening unit 13 and the second straightening unit 14.

[0054] The workpiece 40 is moved to the next processing position by the feed mechanism 11 and processed by the second straightening unit 14. The second straightening unit 14 applies stress to the workpiece 40 by pressing the workpiece 40 against the guide rollers 16b and 16c.

[0055] The workpiece 40 is moved to the next processing position by the feed mechanism 11 and processed by the guide rollers 16c. The guide rollers 16c press the workpiece 40 against the second straightening unit 14 and the third straightening unit 15, thereby applying stress to the workpiece 40.

[0056] The workpiece 40 is moved to the next processing position by the feed mechanism 11 and processed by the third straightening unit 15. The third straightening unit 15 applies stress to the workpiece 40 by pressing the workpiece 40 against the guide rollers 16c and 16d.

[0057] Unlike the other rollers, the guide rollers 16a and 16d only have the function of guiding the workpiece 40 for processing.

[0058] (Configuration of control device 20) The control device 20 includes a characteristic acquisition unit (determination unit) 21, a state acquisition unit 22, a measurement unit 23, a correction unit 24, a determination unit 25, and a storage unit 30. The storage unit 30 stores programs and parameters for operating the control device 20. The storage unit 30 stores material characteristics 31 and a state 32.

[0059] The characteristic acquisition unit 21 is a functional block that acquires the material characteristic (stress-strain characteristic) 31 of the workpiece 40 from the storage unit 30. The characteristic acquisition unit 21 also instructs the first correcting unit 13 on a first displacement amount that applies a load in the elastic region. The characteristic acquisition unit 21 instructs the second correcting unit 14 on a second displacement amount that applies a load in the plastic region.

[0060] The material properties 31 are mechanical constants of the material that are preset in the storage unit 30. The material properties 31 include a stress-strain diagram that shows the relationship between stress and strain of the workpiece 40. The stress-strain diagram includes parameters such as the elastic modulus, plastic modulus, yield stress, or proof stress. Here, the material properties 31 are defined for each of a plurality of positions (processing points) in the X-axis direction of the workpiece 40, and a different stress-strain diagram may be used for each processing point.

[0061] The state acquisition unit 22 is a functional block that acquires the state 32 of the workpiece 40 fed from the supply unit 12. The state acquisition unit 22 acquires the state of the workpiece 40 measured by a state measuring device 17 such as a laser displacement meter or a camera.

[0062] Here, the condition measuring device 17 measures the distance of the workpiece 40 after being fed from the contact surface of the fixed guide rollers 16a to 16d (residual strain in the Z-axis direction) or the radius of curvature (of an arc in the XZ plane) of the workpiece 40 after being fed. The condition measuring device 17 is not limited to these, and may be any means for indirectly measuring the residual strain of the workpiece 40 after being fed.

[0063] The status acquisition unit 22 stores the acquired status 32 in the storage unit 30.

[0064] The state 32 is a parameter that represents the state measured by the state acquisition unit 22, the state in which the workpiece 40 is fed from the supply unit 12, or the processing state during processing (during straightening). The roll unwinding radius in the supply section 12 (the unwinding position of the workpiece) Distance from the contact surface of the fixed guide rollers 16a to 16d before correction The radius of curvature (or curvature in the longitudinal direction) of the workpiece 40 before straightening Residual distortion of workpiece 40 after straightening The residual strain for each of these states 32 may be experimentally derived in advance using an outline and the data may be simply acquired without measuring it inside the straightening device 1. Here, the state 32 is defined for each of a plurality of positions (processing points) in the X-axis direction of the workpiece 40, and a different stress-strain diagram may be used for each processing point.

[0065] The measuring unit 23 acquires a first load (measured load) from the first load cell 132 of the first correcting unit 13 and a first displacement amount (measured displacement amount) from the first moving mechanism 133. The measuring unit 23 also acquires a second load (measured load) from the second load cell 142 of the second correcting unit 14 and a second displacement amount (measured displacement amount) from the second moving mechanism 143. The acquired load and displacement amount are output to the correcting unit 24.

[0066] Based on the acquired load and displacement, the correction unit 24 corrects the state 32 and material properties 31. The correction method will be described in detail later.

[0067] Based on the state 32 and the material properties 31, the determination unit 25 determines a third load (straightening load) or a third displacement amount (straightening displacement amount) in the third straightening unit 15 so that the state after processing in the third straightening unit 15 becomes a desired state (for example, a state without residual strain), and issues a command to the third straightening unit 15. The third load is a load applied by moving the third straightening roller by the third displacement amount in the Z direction using the third moving mechanism 153.

[0068] §3. Example FIG. 3 is a flowchart showing the operation flow of the straightening device 1 according to the first embodiment. FIG. 4 is a data flow diagram in the control device 20 according to the first embodiment. Here, the flowcharts and data flow diagrams in FIGS. 3 and 4 are for processing the same processing point on the workpiece 40. This processing will be explained in detail below. Measurement is performed on a certain processing point, the stress-strain diagram of the processing point is corrected based on the measurement results, and further straightening is performed on the same processing point. This processing is performed sequentially on successive processing points on the workpiece 40.

[0069] In S11, the characteristic acquisition unit 21 acquires the standard material characteristics 31 of the workpiece 40 stored in advance in the storage unit 30. The acquired material characteristics 31 are stored in the storage unit 30 for each processing point.

[0070] In S12, the state acquisition unit 22 acquires the state 32 of the workpiece 40 before correction from the state measuring instrument 17. The acquired state 32 is stored in the storage unit 30.

[0071] At this time, as shown in D12, the state acquisition unit 22 calculates the initial residual strain from the state of the radius of curvature due to bending in the longitudinal direction and the payout (unwinding) position in the radial direction, for example.

[0072] In S13, the characteristic acquisition unit 21 identifies a first displacement amount for applying a load in the elastic region based on the initial residual strain and the stress-strain diagram in the elastic region for the acquired material characteristics 31. The first displacement amount is a value within a range that applies a load in the elastic region while taking into account variations in the state 32. The characteristic acquisition unit 21 instructs the first correction unit 13 to perform correction using the first displacement amount. The first correction unit 13 moves by the first displacement amount and applies the first load to the workpiece 40.

[0073] At this time, as shown in D13, the state acquisition unit 22 uses the initial residual strain obtained in D12 as the initial point and applies a preset reference stress-strain diagram to obtain a stress-strain diagram at the processing point. That is, the reference stress-strain diagram stored in the storage unit 30 is shifted in the horizontal axis direction (strain direction) to obtain a stress-strain diagram at the processing point.

[0074] In S14, the measurement unit 23 acquires the first load and the first displacement amount from the first corrector 13. The acquired first load and first displacement amount are output to the correction unit 24. The measurement unit 23 may acquire the first displacement amount from the characteristic acquisition unit 21.

[0075] At this time, as shown in D14, the characteristic acquisition unit 21 may determine a target load that falls within the elastic region in the stress-strain diagram and derive a first displacement amount that corresponds to that load. Furthermore, the first moving mechanism 133 of the first correcting unit 13 may be controlled to achieve that first displacement amount. The control device 20 processes the measured first load as the load actually applied to the workpiece 40 based on the first displacement amount, and performs subsequent processing. In other words, the measurement unit acquires the first load or the first displacement amount during the period in which the first correcting unit applies the load.

[0076] In S15, the correction unit 24 calculates correction values ​​for the material properties 31 and the state 32 based on the first load and the first displacement amount, and updates the material properties 31 and the state 32 stored in the storage unit 30.

[0077] At this time, as shown in D15, the correction unit 24 acquires the first load and the first displacement measured from D14 and corrects the elastic region of the stress-strain diagram. As will be described later, the correction unit 24 may correct the plastic region in conjunction with correcting the elastic region of the stress-strain diagram.

[0078] In S16, the characteristic acquisition unit 21 applies a load in the plastic region to the workpiece 40 by the second correcting unit 14, taking into consideration the variations in the state 32 based on the stress-strain diagram in the plastic region.

[0079] At this time, as shown in D16, the characteristic acquisition unit 21 determines a target load that falls within the plastic region in the stress-strain diagram and identifies a second displacement amount that corresponds to this load. The second displacement amount is a value within a range that applies a load in the plastic region, taking into account the variation in the state 32. Furthermore, the second movement mechanism 143 of the second straightening unit 14 is moved to achieve this second displacement amount, and a second load is applied to the workpiece 40. This second load is the load applied to the workpiece 40 by the second straightening unit 14 that has moved the second displacement amount.

[0080] In S17, the measurement unit 23 acquires the second load and the second displacement amount during the period when the load is being applied by the second correction unit 14 from the second correcting unit 14. The acquired second load and second displacement amount are output to the correction unit 24. The measurement unit 23 may acquire the second displacement amount from the characteristic acquisition unit 21.

[0081] At this time, as shown in D16, the control device 20 regards the measured second load as the load actually applied to the workpiece 40 based on the second displacement amount, and performs subsequent processing.

[0082] In S18, the correction unit 24 calculates correction values ​​for the material properties 31 and the state 32 based on the second load and the second displacement amount, and updates the material properties 31 and the state 32 stored in the storage unit 30.

[0083] At this time, as shown in D18, the correction unit 24 acquires the second load and the second displacement measured from D16, and corrects the plastic region of the stress-strain diagram.

[0084] In S19, the determination unit 25 determines the third load or the third displacement amount based on the material properties 31 and the state 32.

[0085] At this time, as shown in D19, the determination unit 25 determines a target residual strain in the stress-strain diagram and derives a third displacement amount corresponding to the target residual strain. The third displacement amount is a displacement amount that creates a desired residual strain by applying a load in the plastic region based on the corrected stress-strain diagram. A method for deriving the third displacement amount corresponding to the target residual strain will be described later. The third correction unit 15 moves by the third displacement amount, and the load during the period in which the load is applied to the workpiece 40 is set to the third load.

[0086] In S20, the third correcting unit 15 applies the determined third load or third displacement to the workpiece 40.

[0087] At this time, as shown in D19, the determination unit 25 may control the third movement mechanism 153 of the third correcting unit 15 so as to achieve the third displacement amount. Furthermore, as shown in D18, the correction unit 24 acquires the third load and the third displacement amount measured from D19 and further corrects the plastic region of the stress-strain diagram. By repeating this process, the residual strain converges to the target value.

[0088] Here, the first straightening unit 13, the second straightening unit 14, and the third straightening unit 15 applied loads to the workpiece 40 by moving the positions of the respective moving mechanisms 133, 143, and 153 by displacement amounts controlled by the control device 20. While the respective loads at that time were the first load, the second load, and the third load, the relationship between the displacement amounts and the loads is not limited to a relationship in which a load is generated by a displacement amount. For example, the relationship may be such that the torque (force) of the moving mechanisms 133, 143, and 153 is controlled to control the respective loads and measure the respective displacement amounts at that time.

[0089] (corrected by initial state 32) Fig. 5 is a model diagram illustrating a method for correcting material properties 31 using a stress-strain diagram. Fig. 5 illustrates an example of a stress-strain diagram in which there is no yield point, such as a non-ferrous metal, but the present invention is not limited to this and may also be applied to a material that has a yield point, such as mild steel.

[0090] The stress-strain diagram 50a is a diagram showing a reference stress-strain diagram 51 preset by a user, a line 52 (shown as a dashed line) representing the characteristics in the elastic region in the stress-strain diagram 51 (shown as a chain line), and a line 53 (shown as a dashed line) representing the characteristics in the plastic region. That is, the stress-strain diagram 50a reflects the material characteristics 31 acquired by the characteristic acquisition unit 21. The characteristic acquisition unit 21 may also acquire the stress-strain diagram itself rather than individual items such as the elastic coefficient, plastic coefficient, yield stress, or proof stress. The storage unit 30 may previously store the line 52 representing the characteristics in the elastic region and the line 53 representing the characteristics in the plastic region, which are simple representations of the stress-strain characteristics, or may previously store the stress-strain diagram 51 expressed as a curve.

[0091] The stress-strain diagram 50b is a diagram obtained by the state acquisition unit 22 that shows the state of the stress-strain diagram based on the (initial) residual strain of the workpiece 40 unwound from the supply unit 12. First, the initial residual strain 54 is plotted, and a straight line 55 (shown as a solid line) that is parallel to the line 52 passing through the initial residual strain 54 is derived. The straight line 55 is a line that represents the characteristics in the elastic region, taking the initial residual strain 54 into consideration, as determined by the state acquisition unit 22.

[0092] The steps corresponding to the stress-strain diagrams 50a and 50b correspond to the data flow shown in D13.

[0093] (Correction in the elastic region by the first correcting unit 13) The stress-strain diagram 50c shows how the correction unit 24 corrects the stress-strain diagram when an external force in the elastic region is applied by the first correcting unit 13. The measurement unit 23 plots a point 56 corresponding to the first load and the first displacement on the stress-strain diagram 50c. The correction unit 24 derives a straight line 57 (shown as a solid line) that passes through the initial residual strain 54 and the point 56. The straight line 57 represents the characteristics in the elastic region, taking into account the measurement results of the measurement unit 23, which measured the load applied by the first correcting unit 13, by the correction unit 24.

[0094] Stress-strain diagram 50d shows the process of deriving the characteristics in the plastic region by correction unit 24. The intersection of lines 52 and 53 corresponds to the original yield strength, and line 58 (shown as a two-dot chain line) is derived, parallel to the horizontal axis, passing through the point corresponding to the yield strength. Intersection 59 of line 58 with line 57, which indicates the corrected characteristics in the elastic region, is derived.

[0095] The stress-strain diagram 50e is derived by the correction unit 24 to represent the characteristics in the plastic region. The correction unit 24 derives a straight line 60 (shown as a solid line) that passes through the intersection 59 and is parallel to the line 53 that represents the characteristics in the plastic region. This is a process for correcting the slope (elastic modulus) of the line 57 that represents the characteristics in the elastic region without changing the yield strength. The straight line 60 is a line that represents the characteristics in the plastic region, which is derived by the correction unit 24 in consideration of the measurement results of the measurement unit 23 that measured the load applied by the first correcting unit 13.

[0096] The steps corresponding to the stress-strain diagrams 50c to 50e correspond to the data flow shown in D15.

[0097] (Correction in the plastic region by the second correcting unit 14) The stress-strain diagram 50f shows how the correction unit 24 corrects the stress-strain diagram when an external force in the plastic region is applied by the second correcting unit 14. The measurement unit 23 plots a point 61 corresponding to the second load and the second displacement on the stress-strain diagram 50f. The correction unit 24 derives a straight line 62 (shown as a solid line) that passes through the point 61 and is parallel to the line 53 that represents the characteristics in the plastic region. The straight line 62 is a line that the correction unit 24 calculates by taking into account the measurement results of the measurement unit 23 that measured the load applied by the second correcting unit 14.

[0098] The process corresponding to the stress-strain diagram 50f corresponds to the data flow shown in D18.

[0099] The above-described process has been described with respect to the case where correction is made without changing the plastic coefficient of the plastic region. Here, for example, instead of drawing parallel straight line 62, to correct the plastic coefficient, a straight line passing through point 61 with a slope between the slope of the line connecting intersection point 59 and point 61 and the slope of line 62 may be drawn, and this may be used as the stress-strain diagram in the plastic region. This process corrects the slope of the line (plastic coefficient) that indicates the characteristics of the plastic region.

[0100] (Deformation caused by guide roller 16c) FIG. 6 is a model diagram for deriving the third load or the third displacement from the corrected material properties 31 using a stress-strain diagram. The stress-strain diagram 50g (the line 63) represents the stress-strain diagram when an external force in the elastic region is applied by the guide roller 16c. The determination unit 25 derives the line 63 (shown as a solid line) in the stress-strain diagram 50g that is parallel to the line 57 passing through the point 61. The line 63 represents the deformation in the elastic region of the workpiece 40 when the second load is applied and then reduced (the load is applied in the opposite direction).

[0101] Stress-strain diagram 50h represents the stress-strain diagram when an external force in the plastic region is applied by guide roller 16c. Using initial residual strain 54 as a base point, determination unit 25 translates lines 57 and 62 to intersection 65 between line 63 and the horizontal axis. Then, the two translated lines are rotated 180° around intersection 65. Line 66 (shown as a solid line) is the line obtained by translating and rotating line 62. Line 66 represents the deformation (straightening) of workpiece 40 in the plastic region when stress is applied in the opposite direction (downward).

[0102] 7 is a model diagram for calculating the amount of deformation caused by guide roller 16c. The second straightening roller in second straightening unit 14 is a roller with a radius r22 centered at (x22, y22). Guide roller 16c is a roller with a radius r13 centered at (x13, y13). The third straightening roller in third straightening unit 15 is a roller with a radius r23 centered at (x23, y23). Furthermore, the shape of workpiece 40 straightened by these three rollers is, in a localized sense, an arc with a curvature radius r4 centered at (x4, y4).

[0103] Therefore, the following relationship can be obtained from the Pythagorean theorem:

[0104] (x22-x4) 2 +(y22-y4) 2 =(r22+r4) 2 (x13-x4) 2 +(y13-y4) 2 =(r13-r4) 2 (x23-x4) 2 +(y23-y4) 2 =(r23+r4) 2 By solving these for r4, the radius of curvature r4 of the static workpiece 40 corrected by these three rollers is obtained.

[0105] The strain ε4 is derived from this radius of curvature r4.

[0106] ε4=1 / r4×distance from the center of the workpiece Here, the distance from the center of the workpiece is the thickness from the center of the workpiece to the surface of the workpiece in the correction direction when the workpiece is viewed from a direction perpendicular to the correction plane. In addition, the determining unit 25 derives a point 67 on the line 66 in the stress-strain diagram 50h where the strain is ε4.

[0107] (Correction by the third correction unit 15) The stress-strain diagram 50i is a diagram representing the stress-strain diagram when an external force is applied by the third correcting unit 15. The determining unit 25 derives a straight line 68 (shown as a solid line) in the stress-strain diagram 50i that passes through the point 67 and is parallel to the line 57. The straight line 68 represents deformation in the elastic region of the workpiece 40 when stress is again applied upward by the third correcting unit 15.

[0108] The determination unit 25 translates the lines 57 and 62, starting from the initial residual strain 54, to an intersection 69 between the line 68 and the horizontal axis. The line translated from the line 62 is defined as a line 70 (shown as a solid line). The line 70 represents the deformation in the plastic region of the workpiece 40 when stress is applied again in the positive direction (upward).

[0109] Thereafter, the workpiece 40 is plastically deformed along the straight line 70 by the third straightening unit 15. In Fig. 7, the radius of curvature r5 and the strain ε5 of the workpiece 40 straightened by the third straightening unit 15 are derived from Pythagoras' theorem in the same manner as in the method described above. Here, the guide roller 16d is a roller with a radius r14 centered at (x14, y14).

[0110] (x13-x5) 2 +(y13-y5) 2 =(r13+r5) 2 (x23-x5) 2 +(y23-y5) 2 =(r23-r5) 2 (x14-x5) 2 +(y14-y5) 2 =(r14+r5) 2 ε5=1 / r5×distance from the center of the workpiece The strain ε5 and the target residual strain εt (for example, the case of a residual strain of 0 is shown) are plotted on the stress-strain diagram 50i, and a straight line 71 (shown as a solid line) passing through these two points is derived. This straight line 71 represents the deformation of the workpiece 40 when the load is removed after stress is applied again by the third correcting unit 15.

[0111] Furthermore, the strain ε5 does not have to be calculated using a formula. For example, a line 71 parallel to the line 57 passing through the desired residual strain εt may be derived, and the strain ε5 may be derived from the intersection of the line 71 and the line 70. In this case, any desired residual strain εt can be easily created.

[0112] The load that causes plastic deformation in the workpiece 40 may be smaller for the rollers in the later stages. The third displacement amount may be smaller than the second displacement amount, and the third load may be smaller than the second load. This allows the residual strain to approach zero, and the workpiece 40 to be straightened or flattened.

[0113] (Compensation due to bow sinker effect) Generally, the Bow Sinker effect is known, in which the yield strength decreases from the initial yield strength when the stress is reversed from a certain direction to an opposite direction. Taking the Bow Sinker effect into consideration, the change in the yield strength of the guide roller 16c may be considered. Furthermore, the change in the yield strength of the third straightening section 15 may be considered.

[0114] Furthermore, the strains ε4 and ε5 may be corrected according to the feed speed of the workpiece 40 by the feed mechanism 11. This takes into consideration the effect of the processing speed. These corrections may be made based on the results obtained in advance by experiments or the like.

[0115] §4. Action and Effects It has been shown that the material properties are corrected by the first straightening unit 13 and the second straightening unit 14, and then the workpiece 40 can be deformed to a desired residual strain by the guide roller 16c, the third straightening unit 15, and the guide roller 16d. The desired residual strain εt is, for example, 0, and when the residual strain εt is 0, the workpiece is in a state where it has no curling tendency in the processing direction.

[0116] The external forces applied to the workpiece 40 by the first straightening unit 13, the second straightening unit 14, and the third straightening unit 15 can be controlled based on measured values, thereby preventing the application of excessive external forces. As a result, the workpiece 40 can be straightened without excessively generating lattice defects or cracks inside. In other words, the accumulation of fatigue can be suppressed after the residual strain in the workpiece 40 is removed.

[0117] The state acquisition unit 22 acquires the state of the workpiece 40 when it is unwound, in particular the residual strain before processing, and determines the external force applied by the first straightening unit 13 and the external force applied by the second straightening unit 14. Furthermore, based on the acquired state 32, the material properties 31, in particular the stress-strain diagram, can be corrected.

[0118] When an external force is applied to the workpiece 40 by the first straightening unit 13, stress and strain can be derived from the first stress and the first displacement amount, and the material properties 31, particularly the elastic region (elastic coefficient) of the stress-strain diagram, can be corrected. Furthermore, when an external force is applied to the workpiece 40 by the second straightening unit 14, stress and strain can be derived from the second stress and the second displacement amount, and the material properties 31, particularly the plastic region (plastic coefficient) of the stress-strain diagram, can be corrected.

[0119] At this time, the second load or the second displacement can be minimized by using the stress-strain diagram corrected by the state acquisition unit 22. Therefore, fatigue accumulated in the workpiece 40 during plastic deformation in the second correcting unit 14 can be suppressed.

[0120] The third load or third displacement amount to be applied by the third correction unit 15 can be derived from the material properties corrected by the correction unit, particularly the stress-strain diagram. The determination unit 25 can determine the third load or the third displacement amount so that the residual strain remaining in the workpiece becomes a desired value when the load due to the third load or the third displacement amount is released.

[0121] [Embodiment 2] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0122] Fig. 8 is a side view of a model diagram showing an overview of the straightening device 2 according to embodiment 2. Fig. 9 is a top view of a model diagram showing an overview of the straightening device 2 according to embodiment 2. In embodiment 1, the arcs of each roller are arranged to exist on the XZ plane, thereby straightening the curl of the workpiece 40 that appears on the XZ plane.

[0123] On the other hand, in the second embodiment, it is possible to correct curling on the XY plane in addition to the correction of curling on the XZ plane in the first embodiment. That is, in the first embodiment, the workpiece 40 is a roll like a wound flat plate, which only needs to be corrected in one direction in the cross-sectional shape, but in the second embodiment, the workpiece 40 is a bobbin like a wound wire, which needs to be corrected in two directions in the cross-sectional shape.

[0124] Therefore, the correction device 2 is equipped with, in addition to the first correction section 13, the second correction section 14, the third correction section 15, and the guide rollers 16a to 16d on the XZ plane, a fourth correction section (first correction section) 73, a fifth correction section (first correction section, second correction section) 74, a sixth correction section (second correction section, third correction section) 75, and the guide rollers 76a to 76d on the XY plane.

[0125] The guide rollers 76a to 76d are rollers that are fixed relative to the workpiece 40 and rotate passively. Therefore, a load is applied to the workpiece 40 according to the distance of the guide rollers 76a to 76d from the workpiece 40, thereby straightening the workpiece 40. The guide rollers 76a to 76d are provided on the XY plane. That is, the guide rollers 76a to 76d correspond to the guide rollers 16a to 16d, but are provided in different directions and on different planes.

[0126] The fourth straightening unit 73 is a movable adjustment mechanism composed of a passively rotating fourth straightening roller 731, a fourth load cell 732, and a fourth movement mechanism 733. The fourth movement mechanism 733 moves the position of the fourth straightening roller 731 in the Y-axis direction, thereby applying a load to the workpiece 40. At this time, the fourth load cell 732 can measure the load applied to the workpiece 40. The fourth straightening roller 731 of the fourth straightening unit 73 is provided on the XY plane. In other words, the fourth straightening unit 73 corresponds to the first straightening unit 13, but is provided on a different plane.

[0127] The fifth straightening unit 74 is a movable adjustment mechanism composed of a passively rotating fifth straightening roller 741, a fifth load cell 742, and a fifth movement mechanism 743. The fifth movement mechanism 743 moves the position of the fifth straightening roller 741 in the Y-axis direction, thereby applying a load to the workpiece 40 and straightening the workpiece 40. At this time, the fifth load cell 742 can measure the load applied to the workpiece 40. The fifth straightening roller 741 of the fifth straightening unit 74 is provided on the XY plane. In other words, the fifth straightening unit 74 corresponds to the second straightening unit 14, but is provided on a different plane.

[0128] The sixth straightening unit 75 is a movable adjustment mechanism composed of a passively rotating sixth straightening roller 751, a sixth load cell 752, and a sixth movement mechanism 753. The sixth movement mechanism 753 moves the position of the sixth straightening roller 751 in the Y-axis direction, thereby applying a load to the workpiece 40 and straightening the workpiece 40. At this time, the sixth load cell 752 can measure the load applied to the workpiece 40. The sixth straightening roller 751 of the sixth straightening unit 75 is provided on the XY plane. In other words, the sixth straightening unit 75 corresponds to the third straightening unit 15, but is provided on a different plane.

[0129] The fourth correcting unit 73, the fifth correcting unit 74, and the sixth correcting unit 75 are controlled by the control device 20, which can set the positions of the respective moving mechanisms 733, 743, and 753 and control the respective displacement amounts. The torque of each of the moving mechanisms 733, 743, and 753 may also be controlled to control the respective loads.

[0130] In the second embodiment, the supply unit 12 may take the form of a bobbin around which the workpiece 40 is wound not only in the radial direction of the roll but also in the Y-axis direction as shown in Fig. 9. Therefore, the state acquisition unit 22 may also acquire, as the state 32, the position at which the workpiece 40 is supplied from the supply unit 12 (the unwinding position in the Y-axis direction).

[0131] In the straightening device 2 according to the second embodiment, the first straightening unit 13, the second straightening unit 14, the third straightening unit 15, and the guide rollers 16a to 16d on the XZ plane can remove the curling tendency in the radial direction (Z component) of the supply unit 12 on the XZ plane. Then, in the straightening device 2, the fourth straightening unit 73, the fifth straightening unit 74, the sixth straightening unit 75, and the guide rollers 76a to 76d on the XY plane can remove the curling tendency in the depth direction (depth direction of the bobbin) (Y component) of the supply unit 12 on the XY plane.

[0132] Therefore, the straightening device according to the second embodiment can process (straighten) even shapes that require straightening in two directions, such as a circular cross-sectional shape.

[0133] [Embodiment 3] Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals will be used to designate components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

[0134] 10 is a model diagram showing an overview of the straightening device 3 according to the third embodiment. In the first and second embodiments, seven straightening rollers and seven guide rollers are provided for each plane, but the number of rollers is not limited. In the straightening device 3 according to the third embodiment, the number of rollers is five, and a guide roller 16a, a second straightening unit 14, and a guide roller 16d are provided in this order on the upper surface of the workpiece, and a first straightening unit 13 and a third straightening unit 15 are provided in this order on the lower surface of the workpiece.

[0135] Therefore, the number of rollers is reduced, and therefore, in the third embodiment, the residual strain of the workpiece 40 can be removed in a smaller space than in the first embodiment.

[0136] In addition, in the above-described third embodiment, the first straightening unit 13 and the third straightening unit 15 are on the same side of the workpiece 40, and the second straightening unit 14 is on the opposite side of the workpiece 40, but this is not limiting. For example, the first straightening unit 13 and the second straightening unit 14 may be on the same side of the workpiece 40, and the third straightening unit 15 may be on the opposite side of the workpiece 40, in which case the number of rollers would be six.

[0137] [Variation 1] It is also possible to use only one of the first correcting unit 13 and the second correcting unit 14. In this case, the determining unit uses the preset elastic modulus or plastic modulus as is for either the elastic region or the plastic region in the stress-strain diagram.

[0138] Furthermore, by omitting either the first straightening unit 13 or the second straightening unit 14, some of the guide rollers are also eliminated, making it possible to perform straightening in a smaller space than in the first embodiment.

[0139] [Variation 2] In the first embodiment, when the stress-strain diagram (or elastic modulus) in the elastic region is corrected by the correction unit 24, the stress-strain diagram (or plastic modulus) in the plastic region is also corrected at the same time. This is a measure to prevent the yield stress or proof stress of the workpiece 40 from changing.

[0140] When the workpiece 40 is processed (deformed and straightened), the yield stress or proof stress also changes due to work hardening. Therefore, when correcting the stress-strain diagram in the elastic region, it is not necessary to correct the stress-strain diagram in the plastic region.

[0141] However, in the first embodiment, the stress-strain diagram in the plastic region is also corrected in conjunction with the correction of the stress-strain diagram in the elastic region. Therefore, in the second modification, the steps of stress-strain diagrams 50d and 50e in the first embodiment are omitted, and the intersection of the corrected straight line 57 in the elastic region and the preset straight line 53 in the plastic region is set as the yield point. This approach makes it possible to reproduce work hardening, in which the yield stress or proof stress changes with plastic deformation.

[0142] [Variation 3] In embodiment 1, the load applied to the workpiece 40 by the first correction unit 13 and the second correction unit 14 is determined by the characteristic acquisition unit 21 based on the material characteristics 31, but this is not limited to this.

[0143] For example, the load to be applied to the workpiece 40 by the first correcting unit 13 and the second correcting unit 14 may be determined by taking into consideration the state 32 acquired by the state acquiring unit 22 in addition to the material properties 31. In this case, a load can be applied that takes variations into consideration, thereby preventing an excessive load from being applied to the workpiece 40.

[0144] [Software implementation example] The functions of the control device 20 (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device (particularly each part included in the control device 20).

[0145] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0146] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0147] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0148] Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI ​​may run on the control device or on another device (for example, an edge computer or a cloud server).

[0149] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0150] 1, 2, 3 Orthodontic device 11 Feeding mechanism 12 Supply section 13 1st Correctional Department (1st Correctional Department) 14 Second Correction Department (First Correction Department, Second Correction Department) 15 Third Correction Department (Second Correction Department, Third Correction Department) 16a~16d, 76a~76d Guide rollers 17 State Measuring Instruments 20 Control device 21 Characteristics acquisition unit (determination unit) 22 Status acquisition unit 23 Measurement section 24 Correction unit 25 Decision Section 30 Storage section 31 Material properties (stress-strain properties) 32 Status 73 4th Correctional Department (1st Correctional Department) 74 5th Correctional Department (1st Correctional Department, 2nd Correctional Department) 75 6th Correctional Department (2nd Correctional Department, 3rd Correctional Department)

Claims

1. A control device for a correction device having at least two correction units that apply a load, a characteristic acquisition unit for acquiring stress-strain characteristics of a rolled workpiece; a measuring unit that measures a first load and a first displacement amount during a period in which a load is applied to the workpiece by a first correcting unit; a correction unit that corrects the stress-strain characteristic indicating a relationship between stress and strain of the workpiece based on the first load and the first displacement amount; a determination unit that determines a second load or a second displacement amount to be applied to the workpiece by a second correcting unit subsequent to the first correcting unit based on the corrected stress-strain characteristic.

2. the first load is less than a load that plastically deforms the workpiece; The control device according to claim 1 , wherein the correction unit corrects the characteristics of an elastic region in the stress-strain characteristics.

3. A control device for a correction device having at least two correction units that apply a load, a characteristic acquisition unit for acquiring stress-strain characteristics of a rolled workpiece; a measuring unit that measures a first load and a first displacement amount during a period in which a load is applied to the workpiece by a first correcting unit; a correction unit that corrects the stress-strain characteristics based on the first load and the first displacement amount; a determination unit that determines a second load or a second displacement amount to be applied to the workpiece by a second correcting unit subsequent to the first correcting unit based on the corrected stress-strain characteristic, the first load is less than a load that plastically deforms the workpiece; the correction unit corrects the characteristics of an elastic region in the stress-strain characteristics, The control device wherein the correction unit corrects the characteristics of the plastic region so that the predetermined yield stress or proof stress of the workpiece does not change.

4. the first load is equal to or greater than a load that causes plastic deformation of the workpiece, The control device according to claim 1 , wherein the correction unit corrects the characteristics of a plastic region in the stress-strain characteristics.

5. Further provided is a state acquisition unit that acquires a state of the workpiece before processing, The control device according to claim 1 , wherein the corrector corrects the stress-strain characteristic based on the state, the first load, and the first displacement amount.

6. The control device according to claim 5 , wherein the condition is at least one of a residual strain in the workpiece, a curvature of the workpiece in the longitudinal direction, and a payout position of the workpiece.

7. The control device according to claim 1 , 2 or 4 , wherein the correction unit corrects the elastic modulus, plastic modulus, yield stress or proof stress of the workpiece in the stress-strain characteristics.

8. The control device according to any one of claims 1 to 7, wherein the determination unit determines the second load or the second displacement amount so that the residual strain of the workpiece when the second load is removed becomes a desired value.

9. The control device according to claim 1 , wherein the second load is equal to or greater than a load that causes plastic deformation of the workpiece.

10. the straightening device includes a third straightening unit located on the opposite side of the workpiece from the second straightening unit and located downstream of the second straightening unit, the measuring unit measures the second load or the second displacement amount during a period in which the second correcting unit applies a load to the workpiece; the correction unit corrects the stress-strain characteristic indicating a relationship between stress and strain of the workpiece based on the second load and the second displacement amount; The control device according to claim 9 , wherein the determination unit determines a third load or a third displacement amount applied to the workpiece by the third correcting unit based on the corrected stress-strain characteristic.

11. The control device according to claim 1 , wherein the first straightening unit and the second straightening unit are located on the same side with respect to the workpiece.

12. A correction device comprising the control device according to any one of claims 1 to 11.

13. A control method for a correction device having at least two correction units that apply a load, a characteristic acquisition step of acquiring stress-strain characteristics of the workpiece wound in a roll shape; a measuring step of measuring a first load and a first displacement amount during a period in which a load is applied to the workpiece by a first correcting unit; a correcting step of correcting the stress-strain characteristics based on the first load and the first displacement amount; a determining step of determining a second load or a second displacement amount to be applied to the workpiece by a second correcting unit subsequent to the first correcting unit based on the corrected stress-strain characteristic, the first load is less than a load that plastically deforms the workpiece; In the correction step, a characteristic of an elastic region in the stress-strain characteristic is corrected, In the correction step, the characteristics of the plastic region are corrected so that the predetermined yield stress or proof stress of the workpiece does not change.

14. A control method for a correction device having at least two correction units that apply a load, a characteristic acquisition step of acquiring stress-strain characteristics of the workpiece wound in a roll shape; a measuring step of measuring a first load and a first displacement amount during a period in which a load is applied to the workpiece by a first correcting unit; a correcting step of correcting the stress-strain characteristic indicating a relationship between stress and strain of the workpiece based on the first load and the first displacement amount; and a determining step of determining a second load or a second displacement amount to be applied to the workpiece by a second correcting unit subsequent to the first correcting unit based on the corrected stress-strain characteristic.

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