Workpiece clamping device, workpiece processing method, and workpiece transfer system

Abstract

To provide a workpiece clamping device that can accurately machine workpieces that have long dimensions in the longitudinal direction. [Solution] The work clamping device comprises at least two work support members installed at intervals, an end detection sensor for detecting the end of the workpiece, and a control device. Each work support member has a plurality of rollers and a motor that rotates at least one of the plurality of rollers to feed the workpiece in the direction of the roller's rotation. The control device controls the motor's operation during workpiece processing based on position information of the longitudinal end of the workpiece detected by the end detection sensor and motor output information.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a workpiece clamping device that holds an elongated workpiece during processing, a processing method for the workpiece, and a transfer system for the workpiece. BACKGROUND ART

[0002] Patent Document 1 discloses a double-side grinding apparatus for a workpiece, which grinds the workpiece from both sides with a pair of left and right grinding wheels while feeding the workpiece while supporting the workpiece with rollers arranged vertically and horizontally. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] PATENT DOCUMENT 1 Japanese Unexamined Patent Application Publication No. 2016-7671 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] Incidentally, a workpiece having a long dimension in the longitudinal direction is prone to distortion. In addition, a workpiece that has been subjected to bending processing and has a long dimension in the longitudinal direction tends to have poor shape accuracy. When such a workpiece is processed using the structure described in Patent Document 1, the position and posture of the workpiece change according to the longitudinal position of the workpiece during processing, which tends to cause variations in the quality of the processed workpiece.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a workpiece clamping device, a workpiece processing method, and a workpiece transfer system that can perform processing with high accuracy even on a workpiece having a long dimension in the longitudinal direction, particularly a workpiece that has been subjected to bending processing and has a long dimension in the longitudinal direction. MEANS FOR SOLVING THE PROBLEMS

[0006] A work clamping device for clamping a longitudinal workpiece when processing it, according to an aspect of the present disclosure, comprises at least two work support members installed at intervals from each other, an end detection sensor for detecting the end of the workpiece, and a control device, each of the work support members having a plurality of rollers and a motor that rotates at least one of the plurality of rollers to feed the workpiece in the direction of rotation of the roller, and the control device controls the driving of the motor during processing of the workpiece based on position information of the longitudinal end of the workpiece detected by the end detection sensor and output information of the motor.

[0007] Furthermore, a workpiece processing method according to an aspect of the present disclosure comprises a workpiece clamping device including a plurality of rollers, a motor for rotating at least one of the rollers, and an end detection sensor for detecting the end of a longitudinal workpiece, and is a processing method in which the workpiece is processed by a processing machine while the workpiece is held by the workpiece clamping device, the processing method includes, before the start of processing by the processing machine, detecting one end of the longitudinal workpiece with the end detection sensor by rotating the rollers to feed out the workpiece, processing the workpiece with the processing machine while feeding out the longitudinal workpiece by rotating the rollers, and controlling the drive of the motor during processing of the workpiece based on position information of the longitudinal end of the workpiece and output information of the motor.

[0008] Furthermore, a workpiece transfer system according to an embodiment of the present disclosure comprises: a first robot and a second robot each having an end effector at its tip; a workpiece clamping device according to claim 1, disposed between the support bases of the first robot and the second robot and supporting a workpiece; a first stocker installed on the opposite side of the workpiece clamping device, with the first robot in between, and positioned within the reach of the end effector of the first robot; and a second stocker installed on the opposite side of the workpiece clamping device, with the second robot in between, and positioned within the reach of the end effector of the second robot. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide a workpiece clamping device, a workpiece processing method, and a workpiece transfer system that can accurately process even workpieces having long dimensions in the longitudinal direction. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the overall structure of a workpiece grinding system, which is an example of an embodiment of the present disclosure. [Figure 2] Figure 1 is a top view of the work grinding system, seen from above. [Figure 3] This is a flowchart illustrating the process of machining a workpiece using a workpiece grinding system. [Figure 4] This is a side view of the workpiece clamping device, seen from a direction horizontal to the crossbeam. [Figure 5] Figure 4 is a perspective view of the workpiece clamping device. [Figure 6] This is a view of the first workpiece support member from a direction along the crossbeam. [Figure 7] This diagram shows the shape of the first workpiece support member as viewed from a direction along the crossbeam, during workpiece installation and removal. [Figure 8] This diagram shows the workpiece being held by the first to fourth rollers. [Figure 9] This is a block diagram of the control device that controls the workpiece grinding system. [Figure 10] This diagram shows the measurement position of a workpiece using multiple distance sensors. [Figure 11] This diagram illustrates the concept of workpiece orientation error. [Figure 12] This is an example of a correction amount map for positional error in the longitudinal direction of a workpiece. [Figure 13] This is an example of a correction amount map for rotational error relative to the longitudinal direction of a workpiece. [Figure 14A]This is a diagram showing an example of the vertical correction operation when machining the upper surface of the upper plate portion of a workpiece. [Figure 14B] This is a diagram showing another example of the vertical correction operation when machining the upper surface of the upper plate portion of a workpiece. [Figure 15A] This is a diagram showing an example of the rotational direction correction operation when grinding the upper surface of the upper plate portion of a workpiece. [Figure 15B] This is a diagram showing another example of the rotational direction correction operation when grinding the upper surface of the upper plate portion of a workpiece. [Figure 16] This is a flowchart illustrating the control operation by the control device that corrects the position of the processing machine. [Figure 17] This is a diagram showing the structure of the processing machine used in the second embodiment. [Figure 18] This is a diagram showing the relationship between the head pressure applied to the processing brush of the constant pressure device encoder and the tilt angle. [Figure 19] This is a diagram showing the relationship between the head pressure applied to the processing brush and the grinding amount of the workpiece. [Figure 20] This is a block diagram of the control device corresponding to the second embodiment, which controls the workpiece grinding system. [Figure 21] This is a diagram showing the relationship between the elapsed time and the displacement amount during machining of the workpiece. [Figure 22] This is a diagram showing the state when the position and posture of the processing machine are corrected based on the re-estimated shape of the workpiece. [Figure 23] This is a flowchart illustrating the control operation by the control device that corrects the position and posture of the processing machine during workpiece machining. [Figure 24] This is a diagram showing the displacement amount at each point when the workpiece is twisted. [Modes for Carrying Out the Invention]

[0011] The embodiments described below are all specific examples of the present disclosure. The numerical values, shapes, components, steps, and order of steps shown in the following embodiments are examples only and do not limit the present disclosure. Furthermore, among the components in the following embodiments, those components that are not described in the independent claim representing the highest-level concept will be described as optional components.

[0012] [First Embodiment] Figure 1 is a perspective view showing the overall structure of a workpiece grinding system 10, which is an example of an embodiment of the present disclosure. Figure 2 is a top view of the workpiece grinding system 10 as seen from above.

[0013] The work grinding system 10 is a device for grinding the surface of a longitudinally shaped workpiece W. The workpiece W has an arc shape and is long in the longitudinal direction. The work grinding system 10 comprises a processing chamber 12, a first robot 14 positioned in the processing chamber 12, a second robot 16 positioned in the processing chamber 12, a work clamping device 20 positioned above the processing chamber 12 to hold the workpiece W during processing, and a first stocker 22 and a second stocker 24 positioned adjacent to the processing chamber 12. The first robot 14 further comprises a support base 14a, and the second robot 16 further comprises a support base 16a. The work clamping device 20 further comprises a crossbeam 18 positioned above the processing chamber 12. In this embodiment, the direction along the crossbeam 18 is defined as the X direction, the direction perpendicular to the ground, i.e., the up and down direction, is defined as the Z direction, and the direction perpendicular to the crossbeam 18 and the Z direction, i.e., the left and right direction, is defined as the Y direction. These directions are merely added for convenience in the following explanation.

[0014] The processing room 12 comprises a first column 26A, a second column 26B, a third column 26C, and a fourth column 26D, which are arranged on all four sides. The processing room 12 also comprises a first panel 28A positioned between the first column 26A and the second column 26B, a second panel 28B positioned between the third column 26C and the fourth column 26D, a first shutter 30A positioned between the first column 26A and the third column 26C, and a second shutter 30B positioned between the second column 26B and the fourth column 26D.

[0015] The first column 26A, the second column 26B, the third column 26C, and the fourth column 26D are positioned at the four corners of the processing room 12 and are each erected perpendicular to the ground.

[0016] The first panel 28A and the second panel 28B partition the internal space of the processing chamber 12 from the external space, preventing chips and other debris generated during processing from scattering into the external space. The first shutter 30A and the second shutter 30B close during processing to partition the internal space of the processing chamber 12 from the external space, preventing chips and other debris generated during processing from scattering into the external space.

[0017] The first shutter 30A opens when a workpiece W placed in the first stocker 22 is brought into the processing chamber 12, allowing the workpiece W to move into the processing chamber 12. The first shutter 30A opens when a processed workpiece W is brought out to the first stocker 22, allowing the workpiece W to move from the processing chamber 12 to the first stocker 22. The second shutter 30B opens when a workpiece W placed in the second stocker 24 is brought into the processing chamber 12, allowing the workpiece W to move into the processing chamber 12.

[0018] The crossbeam 18 is a longitudinal column positioned above the processing chamber 12 along the X direction. The crossbeam 18 is provided to hold the workpiece clamping device 20.

[0019] The workpiece clamping device 20 is a device that holds the workpiece W above the processing chamber 12. The workpiece clamping device 20 is positioned between the support base 14a of the first robot 14 and the support base 16a of the second robot 16.

[0020] The first robot 14 has the function of taking the workpiece W before processing from the first stocker 22 and transferring it to the workpiece holding position of the workpiece clamping device 20. When the first robot 14 is transporting the workpiece W, a hand 32 is attached to the tip of the first robot 14 as an end effector. When the hand 32 is attached to the tip of the first robot 14 as an end effector, the first robot 14 can grasp and transport the workpiece W. The first robot 14 also has the function of processing the workpiece W held by the workpiece clamping device 20. When processing the workpiece W, a grinding machine 34 is attached to the tip of the first robot 14 as an end effector. The first robot 14 changes the device attached to its tip between the hand 32 and the grinding machine 34 as needed, depending on the work process.

[0021] The second robot 16 has the function of removing the processed workpiece W from the workpiece clamping device 20 and transferring it to the second stocker 24. When the second robot 16 is transporting the workpiece W, a hand 32 is attached to the tip of the second robot 16. The second robot 16 also has the function of processing the workpiece W held by the workpiece clamping device 20. When processing the workpiece W, a grinding machine 34 is attached to the tip of the second robot 16. The second robot 16 changes the device attached to its tip between the hand 32 and the grinding machine 34 as needed, depending on the work process.

[0022] The first stocker 22 is a trolley that holds the workpiece W before processing. The first stocker 22 is positioned on the opposite side of the workpiece clamping device 20, with the first robot 14 in between, and is within the reach of the hand 32 of the first robot 14. Specifically, the first stocker 22 is located outside the processing chamber 12, adjacent to the first shutter 30A.

[0023] The second stocker 24 is a trolley that holds the processed workpieces W. The second stocker 24 is positioned on the opposite side of the workpiece clamping device 20, with the second robot 16 in between, and within the reach of the hand 32 of the second robot 16. Specifically, the second stocker 24 is located outside the processing chamber 12, adjacent to the second shutter 30B. Processed workpieces W are sequentially transferred to the second stocker 24. When the number of workpieces W transferred to the second stocker 24 reaches a predetermined number, the second stocker 24 is moved to another location.

[0024] Figure 3 is a flowchart illustrating the processing flow of workpiece W by the workpiece grinding system 10. In step S10, a first stocker 22, which holds multiple workpieces W before processing, is brought into the loading position of the first stocker 22 as shown in Figures 1 and 2. The second stocker 24 is brought into the loading position of the second stocker 24 as shown in Figures 1 and 2. The second stocker 24 may be brought in beforehand, before the loading of the first stocker 22. In step S20, one workpiece W before processing held in the first stocker 22 is removed by the first robot 14, and the removed workpiece W is transferred to a predetermined holding position of the workpiece clamping device 20. In step S30, the workpiece W is fixed to the workpiece clamping device 20. In step S40, while the workpiece W is held by the workpiece clamping device 20, the workpiece W is fed in the longitudinal direction by the workpiece clamping device 20, and the position of the longitudinal end of the workpiece W is detected. The origin of the workpiece W is set based on the position of the longitudinal end of the workpiece W. In step S50, the shape of the workpiece W before processing is measured. In step S60, the first robot 14 and the second robot 16 process the workpiece W. Once the processing of the workpiece W is complete, in step S70, the shape of the workpiece W after processing is measured. In step S80, the second robot 16 removes the workpiece W from the workpiece clamping device 20 and transfers the workpiece W to the second stocker 24. In step S90, if the number of workpiece W placed in the second stocker 24 reaches a specified number, in step S100, the second stocker 24 is removed. On the other hand, in step S100, if the number of workpiece W has not reached a specified number, the process returns to step S20 and processing of the next workpiece W is performed.

[0025] Thus, in this embodiment, the first robot 14 transports the workpiece W, which is held in the first stocker 22 before processing, to the workpiece clamping device 20, and processes the workpiece W. The second robot 16 transports the processed workpiece W, which is held in the workpiece clamping device 20, to the second stocker 24, and processes the workpiece W. As a result, the workpiece grinding system 10 is smaller in scale compared to a system where separate robots are provided for transporting the workpiece W and for processing the workpiece W.

[0026] [Work clamping device] Next, the workpiece clamping device 20 that holds the workpiece W during processing will be described. Figure 4 is a side view of the workpiece clamping device 20 as seen from the Y direction, which is perpendicular to the X and Z directions, which are the longitudinal directions of the crossbeam 18. Figure 5 is a perspective view of the workpiece clamping device 20 of Figure 4. Figures 4 and 5 show the workpiece clamping device 20 holding an arc-shaped workpiece W.

[0027] The workpiece clamping device 20 includes a crossbeam 18 and a first workpiece support member 40, a second workpiece support member 42, and a third workpiece support member 44 attached to the crossbeam 18. The first workpiece support member 40 and the second workpiece support member 42 are positioned apart in the X direction along the crossbeam 18. The third workpiece support member 44 is positioned between the first workpiece support member 40 and the second workpiece support member 42 with respect to the X direction. As shown in Figure 4, the workpiece W is held in a fixed state by the first workpiece support member 40, the second workpiece support member 42, and the third workpiece support member 44. The workpiece W is held so as to be movable in the X direction relative to the first workpiece support member 40, the second workpiece support member 42, and the third workpiece support member 44. Also, the mounting angle α formed between the first workpiece support member 40 and the third workpiece support member 44, as shown in Figure 4, can be appropriately adjusted according to the shape of the workpiece W, i.e., the radius of the arc of the workpiece W. The mounting angle α is the angle between a line parallel to the longitudinal direction of the first workpiece support member 40 and a line parallel to the longitudinal direction of the second workpiece support member 42, when viewed from the Y direction on the crossbeam 18. For example, the mounting angle α is adjusted to increase as the arc radius of the workpiece W increases. This allows the workpiece W to be held by the same workpiece clamping device 20 even if its dimensions are changed.

[0028] Next, the structure of the first workpiece support member 40 will be described. Figure 6 is a view of the first workpiece support member 40 from the X direction along the crossbeam 18. Figure 7 is a view of the first workpiece support member 40 from the X direction along the crossbeam 18, and shows the shape of the first workpiece support member 40 when the workpiece W is attached to and removed from the first workpiece support member 40.

[0029] The first workpiece support member 40 is a mechanism that holds the workpiece W and feeds the workpiece W in the longitudinal direction. The first workpiece support member 40 comprises a plurality of rollers consisting of a first roller 58, a second roller 60, a third roller 62, and a fourth roller 64, a motor 66 for rotating the third roller 62, a slide mechanism 70 for moving the first roller 58, a cylinder 56, and a roller support member 55 that supports the plurality of rollers, the motor 66, the slide mechanism 70, etc.

[0030] The roller support member 55 protrudes downward from the crossbeam 18 and supports the plurality of rollers, motor 66, and slide mechanism 70, etc. The roller support member 55 comprises a first clamp arm 50A, a second clamp arm 50B, a third clamp arm 50C, a lower support member 52, and an upper support member 54.

[0031] The first clamp arm 50A, the second clamp arm 50B, and the third clamp arm 50C all protrude downward from the crossbeam 18 and are parallel to each other.

[0032] A crossbeam 18, indicated by a dashed line, is positioned between the first clamp arm 50A and the second clamp arm 50B. The first clamp arm 50A and the second clamp arm 50B are connected to the crossbeam 18 via an intermediate member 45. The intermediate member 45 is fixed to the first clamp arm 50A and the second clamp arm 50B.

[0033] The lower support member 52 is connected to the lower end of the first clamp arm 50A and the lower end of the second clamp arm 50B, and is positioned along the Y direction. The lower support member 52 extends in the Y direction toward the third clamp arm 50C side beyond the connection point with the lower end of the second clamp arm 50B.

[0034] The upper support member 54 is connected to the upper end of the second clamp arm 50B and extends perpendicularly to the second clamp arm 50B. In other words, the upper support member 54 extends along the Y direction in the direction of the third clamp arm 50C. The upper support member 54 is a member that supports the third clamp arm 50C.

[0035] The third clamp arm 50C is connected to the tip of the upper support member 54. The upper support member 54 and the third clamp arm 50C are connected via a pivot mechanism 68. Because the upper support member 54 and the third clamp arm 50C are connected via the pivot mechanism 68, the third clamp arm 50C rotates relative to the upper support member 54 with the pivot mechanism 68 as the pivot point.

[0036] The second clamp arm 50B and the third clamp arm 50C are connected to each other via a cylinder 56. Specifically, the base of the cylinder 56 is connected to the vicinity of the longitudinal center of the second clamp arm 50B. The tip of the piston rod of the cylinder 56 is connected to the vicinity of the longitudinal center of the third clamp arm 50C. The third clamp arm 50C is pivotably connected to the tip of the piston rod of the cylinder 56. When the cylinder 56 is retracted, the second clamp arm 50B and the third clamp arm 50C are parallel, as shown in Figure 6. In other words, when the cylinder 56 is retracted, the third clamp arm 50C extends perpendicularly to the upper support member 54. On the other hand, when the cylinder 56 is extended, the third clamp arm 50C rotates counterclockwise around the pivot mechanism 68, as shown in Figure 7. The cylinder 56 may be an air cylinder or a hydraulic cylinder.

[0037] Below the portion of the third clamp arm 50C to which the cylinder 56 is connected, the first roller 58, the fourth roller 64, and the sliding mechanism 70 are mounted. The third clamp arm 50C functions as a first roller support member 55A that supports the first roller 58, the fourth roller 64, and the sliding mechanism 70.

[0038] The portion of the lower support member 52 that protrudes from the second clamp arm 50B has the second roller 60, the third roller 62, and the motor 66 attached to it. The lower support member 52 functions as a second roller support member 55B that supports the second roller 60, the third roller 62, and the motor 66.

[0039] When the cylinder 56 is retracted, the lower support member 52 and the third clamp arm 50C move closer together. That is, the first roller support member 55A and the second roller support member 55B move closer to each other. When the first roller support member 55A and the second roller support member 55B move closer to each other, the state shown in Figure 6 is achieved, and the workpiece W is held by the first roller 58 to the fourth roller 64. When the cylinder 56 is extended, as shown in Figure 7, the first roller 58 and the fourth roller 64 and the second roller 60 and the third roller 62 move apart. That is, the first roller support member 55A and the second roller support member 55B move apart. When the first roller support member 55A and the second roller support member 55B move apart, a space 67 is formed between the first roller 58 and the fourth roller 64 and the second roller 60 and the third roller 62, guiding the workpiece W into the roller support member 55. When the workpiece W is held by the first workpiece support member 40, the workpiece W is placed in a predetermined holding position by passing through the space.

[0040] Figure 8 shows the state in which the workpiece W is held by the first roller 58 to the fourth roller 64, as viewed from the longitudinal direction of the workpiece W. As shown in Figure 8, the workpiece W is held by being sandwiched between the first roller 58, the second roller 60, the third roller 62, and the fourth roller 64.

[0041] Furthermore, the workpiece W has a roughly Z-shaped cross-section when viewed from the longitudinal direction of the workpiece W. Specifically, the workpiece W has a side plate portion W1 extending in the Z direction, i.e., vertical direction, an upper plate portion W2 extending in the Y direction from the upper end of the side plate portion W1, a lower plate portion W3 extending in the Y direction from the lower end of the side plate portion W1, and an end plate portion W4 extending in the Z direction from the tip of the lower plate portion W3. The lower plate portion W3 extends in the opposite direction to the upper plate portion W2 along the Y direction, sandwiching the side plate portion W1. The end plate portion W4 extends in the Z direction from the end of the lower plate portion W3, which is in the opposite direction to the side plate portion W1 in the Y direction. In this embodiment, the upper plate portion W2 and the lower plate portion W3 extend parallel to each other, but the upper plate portion W2 and the lower plate portion W3 do not necessarily have to be parallel. Also, the end plate portion W4 is optional.

[0042] The first roller 58 rotates around the first axis CL1 and contacts the upper surface SU of the upper plate portion W2 while holding the workpiece W. The first axis CL1 is arranged parallel to the Y direction, which is the direction in which the upper plate portion W2 extends.

[0043] The second roller 60 is positioned below the first roller 58 and rotates around a second axis CL2 parallel to the Y direction, which is the direction in which the lower plate portion W3 extends. The second roller 60 contacts the lower surface SD of the lower plate portion W3 when the workpiece W is held. In this embodiment, the first axis CL1 and the second axis CL2 are arranged in parallel. However, if the upper plate portion W2 and the lower plate portion W3 are not arranged in parallel, the first axis CL1 and the second axis CL2 do not have to be parallel, depending on the shapes of the upper plate portion W2 and the lower plate portion W3.

[0044] The third roller 62 is positioned below the first roller 58 and above the second roller 60, and rotates around a third axis CL3 parallel to the Z direction, which is the direction in which the side plate portion W1 extends. The third roller 62 contacts the left side surface SL of the side plate portion W1 when the workpiece W is held.

[0045] The fourth roller 64 is positioned below the first roller 58 and above the second roller 60, and rotates around a fourth axis CL4 parallel to the Z direction, which is the direction in which the side plate portion W1 extends. The fourth roller 64 contacts the right surface SR of the side plate portion W1 while holding the workpiece W.

[0046] The third roller 62 and the fourth roller 64 are positioned on either side of the side plate W1. The fourth roller 64 is positioned with a gap equal to the thickness of the side plate W1 between it and the third roller 62. Alternatively, the fourth roller 64 is positioned with a gap slightly narrower than the thickness of the side plate W1 between it and the third roller 62. The third axis CL3 and the fourth axis CL4 are parallel to each other.

[0047] Furthermore, as shown in Figure 8, the third roller 62 and the fourth roller 64 may be positioned at vertically offset locations. For example, if the dimensions of the third roller 62 and the fourth roller 64 are the same, the lower end of the third roller 62 may be located below the lower end of the fourth roller 64.

[0048] In this embodiment, the third roller 62 is connected to the motor 66 via the rotating shaft 65, and the third roller 62 rotates around the third shaft CL3 by the motor 66. At this time, the first roller 58, the second roller 60, and the fourth roller 64 rotate in response to the movement of the workpiece W due to the rotation of the third roller 62.

[0049] The first roller 58 is attached to the third clamp arm 50C via a sliding mechanism 70. The sliding mechanism 70 moves the first roller 58 perpendicular to the first axis CL1, causing the first roller 58 and the second roller 60 to move apart or closer together. The sliding mechanism 70 may be, for example, an air cylinder.

[0050] As the sliding mechanism 70 brings the first roller 58 closer to the second roller 60, the first roller 58 is pressed against the upper surface SU of the upper plate portion W2 of the workpiece W, and the second roller 60 is pressed against the lower surface SD of the lower plate portion W3 of the workpiece W. As shown in Figure 8, when the workpiece W is held by the first roller 58, the second roller 60, the third roller 62, and the fourth roller 64, the side plate portion W1 of the workpiece W is sandwiched between the third roller 62 and the fourth roller 64. When the third roller 62 rotates in this state, the first roller 58, the second roller 60, and the fourth roller 64 also rotate. At this time, the workpiece W is fed in the longitudinal direction in accordance with the rotation of these rollers. The third roller 62 is a driving roller that applies a force to move the workpiece W in the longitudinal direction. The fourth roller 64 is a driven roller that is pressed against the workpiece W and rotates together with the third roller 62, holding the workpiece W so that it does not slip.

[0051] Since the second workpiece support member 42 has the same structure as the first workpiece support member 40, a detailed explanation of the second workpiece support member 42 is omitted. Furthermore, the third workpiece support member 44 has the same structure as the first workpiece support member 40, but without the first roller 58 and the second roller 60. Since the structure of the third workpiece support member 44 is basically the same as that of the first workpiece support member 40, a detailed explanation of the third workpiece support member 44 is also omitted.

[0052] When processing the workpiece W, the processing machines 34 are pre-attached to the tips of the first robot 14 and the second robot 16. With each processing machine 34 fixed relative to the longitudinal direction of the workpiece W, the workpiece W is held by the first roller 58, the second roller 60, the third roller 62, and the fourth roller 64. By rotating the third roller 62 with the motor 66, the first roller 58, the second roller 60, and the fourth roller 64 also rotate in response, and the workpiece W is fed along its longitudinal direction. At this time, the workpiece W is processed along its longitudinal direction by the processing machine 34.

[0053] The machining center 34 has a structure as shown in Figure 14, for example. As shown in Figure 14, the machining center 34 includes a machining brush 34A and a spindle motor 34B that rotates the machining brush 34A. The surface of the workpiece W that comes into contact with the machining brush 34A is ground by the rotation of the machining brush 34A by the spindle motor 34B.

[0054] During the machining of the workpiece W, when the workpiece W is fed to a predetermined position in the longitudinal direction, the motor 66 is controlled to rotate the third roller 62 in the opposite direction. This causes the workpiece W to be fed in the opposite direction to the previous feeding direction. When the workpiece W is fed in the opposite direction to the previous feeding direction, the workpiece W may or may not be machined by the machining center 34. In addition, each time the workpiece W reaches a predetermined position in the longitudinal direction, the position of the machining center 34 of the first robot 14 and the machining center 34 of the second robot 16 are changed, thereby changing the machined surface of the workpiece W. In this way, the workpiece W is reciprocated in the longitudinal direction by the workpiece clamping device 20, and the machined surface of the machining center 34 of the first robot 14 and the machining surface of the machining center 34 of the second robot 16 are changed as needed, so that the entire machined surface of the workpiece W is ground.

[0055] By the way, in this embodiment, the workpiece W is formed by bending a thin sheet and has a long longitudinal dimension, so distortion is likely to occur in the workpiece W after bending. Also, during processing, the workpiece W is suspended by the workpiece clamping device 20, so deformation due to the workpiece W's own weight is also likely to occur. The position and angle of the processing machine 34 during processing are set in advance based on the design shape of the workpiece W and its placement on the clamping device 20 so that the relative distance and relative angle between the processing surface of the workpiece W and the processing machine 34 remain constant. Therefore, if distortion or deformation exists in the workpiece W, the relative position or relative angle between the processing surface of the workpiece W and the processing machine 34 will change according to the longitudinal position of the workpiece W. When the relative position or relative angle between the processing surface of the workpiece W and the processing machine 34 changes, the grinding amount Sg of the workpiece W becomes unstable, and the processing accuracy decreases.

[0056] In contrast, in this embodiment, as will be described later, the position of the processing machine 34 of the first robot 14 and the position and orientation of the processing machine 34 of the second robot 16 are changed as needed according to the longitudinal position of the workpiece W, thereby stabilizing the grinding amount Sg of the workpiece W and enabling accurate processing of the workpiece W.

[0057] Figure 9 is a block diagram of a control device 100 that controls the workpiece grinding system 10. The control device 100 is a computer that includes a CPU, which is a central processing unit, and storage devices such as ROM and RAM. The CPU retrieves and executes programs stored in the storage devices to perform various processes related to the machining of the workpiece W. The control device 100 may be a dedicated computer located near the workpiece grinding system 10, or it may be located in a terminal located away from the workpiece grinding system 10. In the latter case, the workpiece grinding system 10 and the control device 100 are connected via a communication device.

[0058] The control device 100 includes a motor control unit 80, a robot control unit 82, a workpiece end measurement unit 84, a workpiece posture measurement unit 86, a workpiece error calculation unit 88, a processing machine position correction unit 90, and a workpiece slip detection unit 92.

[0059] The motor control unit 80 controls the drive of the motor 66 during the machining of the workpiece W. The motor control unit 80 controls the drive of the motor 66 during the machining of the workpiece W based on the position information of the longitudinal end of the workpiece W and the rotational speed of the motor 66, which is the output information of the motor 66. In addition, when the motor control unit 80 measures the position of the longitudinal end of the workpiece W, it rotates the motor 66 to feed the workpiece W in the longitudinal direction. Feeding the workpiece W in the longitudinal direction is equivalent to driving the motor 66 to rotate the third roller 62, which in turn rotates the first roller 58, the second roller 60, and the fourth roller 64.

[0060] The robot control unit 82 controls the operation of the first robot 14 and the second robot 16 during the machining of the workpiece W. For example, when the machining process of the workpiece W begins, the robot control unit 82 takes the unmachined workpiece W held in the first stocker 22 and places it on the workpiece clamping device 20. Once the workpiece W is placed on the workpiece clamping device 20, the robot control unit 82 replaces the tips of the first robot 14 and the second robot 16 from the hands 32 to the machining tools 34. Next, the robot control unit 82 moves the two machining tools 34 to their respective machining positions and holds the machining tools 34 immobile relative to the longitudinal direction of the workpiece W during machining. At this time, the robot control unit 82 moves each machining tool 34 to the next machining position each time the workpiece W moves to a predetermined position in the longitudinal direction.

[0061] In this embodiment, considering that the longitudinal dimension of the workpiece W is long, the workpiece W may be divided into multiple regions in the longitudinal direction for processing. For example, the workpiece W may be divided into three regions in the longitudinal direction, from the first region to the third region, and processing may be performed in each region. In this case, when processing of the first region is completed, the robot control unit 82 moves the processing machine 34 of the first robot 14 and the processing machine 34 of the second robot 16 to positions suitable for processing the second region. When processing of the second region is completed, the robot control unit 82 moves the processing machine 34 of the first robot 14 and the processing machine 34 of the second robot 16 to positions suitable for processing the third region.

[0062] When the processing of the workpiece W is complete, the robot control unit 82 replaces the tip sections of the first robot 14 and the second robot 16 from the processing machine 34 to the hand 32. Next, the robot control unit 82 has the second robot 16 remove the processed workpiece W that has been placed on the workpiece clamping device 20 and transfer it to the second stocker 24.

[0063] The workpiece end measurement unit 84 measures the position of the longitudinal end of the workpiece W before processing of the workpiece W begins. The longitudinal end of the workpiece W is detected by the first end detection sensor 72 and the second end detection sensor 74, which are located on both sides of the workpiece clamping device 20 in the longitudinal direction of the workpiece W, as shown in Figure 4. Relatively inexpensive sensors such as photoelectric on / off sensors may be used as the first end detection sensor 72 and the second end detection sensor 74.

[0064] When measuring the position of the longitudinal end of the workpiece W, the motor control unit 80 rotates the motor 66 to move the workpiece W to one side in the longitudinal direction. At this time, when the workpiece W moves to a position where it can no longer be detected by the first end detection sensor 72, the first end detection sensor 72 outputs a signal indicating that the end of the workpiece W has been detected. When the workpiece end measurement unit 84 receives the signal indicating that the workpiece W has moved to one end in the longitudinal direction, it determines that the motor 66 has moved to one end in the longitudinal direction and stores the rotation speed of the motor 66 at the time the workpiece W moved to one side in the longitudinal direction as position information for one end of the workpiece W in the longitudinal direction. The rotation speed of the motor 66 at the time the workpiece moves to one side in the longitudinal direction may be set to zero. The longitudinal position of the workpiece W can be calculated based on the rotation speed of the motor 66, using the rotation speed of the motor 66 at the time the workpiece W moved to one side in the longitudinal direction as a reference. Figure 4 shows the state where the workpiece W has moved to a position where it can no longer be detected by the first end detection sensor 72. At this time, since no signal is received to detect the workpiece W, a signal for detecting the end of the workpiece W is output.

[0065] Next, the motor control unit 80 rotates the motor 66 in the opposite direction to move the workpiece W to the other end in the longitudinal direction. When the workpiece W moves to a position where it cannot be detected by the second end detection sensor 74, the second end detection sensor 74 outputs a signal indicating that the end of the workpiece W has been detected. Upon receiving the end detection signal, the workpiece end measurement unit 84 determines that the workpiece W has moved to the other end in the longitudinal direction and stores the rotation speed of the motor 66 at the time the workpiece W moved to the other end in the longitudinal direction as position information for the other end of the workpiece W in the longitudinal direction.

[0066] When the position information of the longitudinal end of the workpiece W is detected, the motor control unit 80 determines the longitudinal position of the workpiece W currently being processed from the position information of the longitudinal end of the workpiece W and the rotational speed, which is the output information of the motor 66, and controls the drive of the motor 66. For example, when a predetermined position in the longitudinal direction of the workpiece W reaches the end of the processing area of ​​the workpiece W, the motor control unit 80 stops the motor 66. Then, after the processing machine 34 moves to the next processing position, the motor control unit 80 rotates the motor 66 in the opposite direction, feeding the workpiece W in the opposite direction to the previous movement. The longitudinal position of the workpiece W is determined from the rotational speed of the motor 66.

[0067] The workpiece posture measurement unit 86 measures the distance between each distance sensor 76a, 76b, and 76c and the workpiece W along the longitudinal direction of the workpiece W, using a first distance sensor 76a, a second distance sensor 76b, and a third distance sensor 76c, which are located near the workpiece clamping device 20. Figure 10 shows the measurement positions of the workpiece W by each distance sensor 76a, 76b, and 76c.

[0068] The first distance sensor 76a is positioned on the upper part of the workpiece W in the Z direction. The first distance sensor 76a measures the distance L1 between the first distance sensor 76a and a predetermined portion P1 on the upper surface SU of the upper plate portion W2. Alternatively, the first distance sensor 76a may be positioned on the lower part of the workpiece W in the Z direction and measure the distance between the first distance sensor 76a and the lower surface SD of the lower plate portion W3.

[0069] The second distance sensor 76b is positioned to the right of the workpiece W in the Y direction. The second distance sensor 76b measures the distance L2 between the second distance sensor 76b and a predetermined first portion P2 on the right surface SR of the side plate W1. Alternatively, the second distance sensor 76b may be positioned to the left of the workpiece W in the Y direction and measure the distance between the second distance sensor 76b and the left surface SL of the side plate W1.

[0070] The third distance sensor 76c is positioned to the left of the workpiece W in the Y direction. The third distance sensor 76c is positioned differently from the second distance sensor 76b in the Z direction. The third distance sensor 76c measures the distance L3 between the third distance sensor 76c and a predetermined second portion P3 on the left surface SL of the side plate W1. Alternatively, the third distance sensor 76c may be positioned to the right of the workpiece W in the Y direction and measure the distance between the third distance sensor 76c and the right surface SR of the side plate W1.

[0071] Furthermore, the first portion P2 measured by the second distance sensor 76b and the second portion P3 measured by the third distance sensor 76c may be on the same surface of the left side SL or right side SR of the side plate portion W1. In other words, the first portion P2 and the second portion P3 may be in different positions within the range of the left side SL and the right side SR.

[0072] When measuring the distances L1, L2, and L3, the motor control unit 80 rotates the motor 66 to move the workpiece W from one end to the other in the longitudinal direction. At this time, the workpiece attitude measurement unit 86 uses the first distance sensor 76a to measure distance L1 along the longitudinal direction of the workpiece W. Similarly, the workpiece attitude measurement unit 86 uses the second distance sensor 76b to measure distance L2 along the longitudinal direction of the workpiece W. Similarly, the workpiece attitude measurement unit 86 uses the third distance sensor 76c to measure distance L3 along the longitudinal direction of the workpiece W.

[0073] The workpiece error calculation unit 88 measures the distances L1, L2, and L3 for each position in the longitudinal direction of the workpiece W and calculates the workpiece error for each position in the longitudinal direction of the workpiece W. The workpiece error is, for example, the error relative to a preset reference position of the workpiece W. The reference position of the workpiece W is the position when the workpiece W is placed on the workpiece clamping device 20, assuming that the workpiece W is not twisted or distorted. Figure 11 is a diagram showing the workpiece error of the workpiece W. The workpiece error includes the Z-direction position error dz, which is the position error of the workpiece W in the Z direction; the Y-direction position error dy, which is the position error of the workpiece W in the Y direction; and the rotational direction error dθ, which is the rotational direction error of the workpiece W. The rotational direction error dθ is the angle between the side plate portion W1 when the workpiece W has a reference position and the side plate portion W1 when the actual workpiece W is placed on the workpiece clamping device 20. The specific calculation methods for these workpiece errors will be described later.

[0074] [Correction of the machine's position] The following explanation describes the correction of the machining center 34 based on the Z-direction position error dz and the rotational direction error dθ. Although not explained here, in practice, the machining center 34 is also corrected based on the Y-direction position error dy.

[0075] The workpiece error calculation unit 88 calculates the workpiece error for each position in the longitudinal direction of the workpiece W. The machining center position correction unit 90 creates a correction amount map as shown in Figures 12 and 13 based on the calculated workpiece error for each position in the longitudinal direction of the workpiece W. Figure 12 is an example of a correction amount map for the Z-direction position error dz [mm] of the workpiece W with respect to the longitudinal direction. Figure 13 is an example of a correction amount map for the rotational error dθ [deg] of the workpiece W with respect to the longitudinal direction. The correction amount maps shown in Figures 12 and 13 are the correction amounts of the machining center 34 with respect to the elapsed time t during machining of the workpiece W. In this embodiment, the speed at which the workpiece W is fed is set to be the same during measurement and during machining. The correction amount map in Figure 12 is created from the elapsed time t from the start of measurement and the Z-direction position error dz calculated based on the distance L1. The correction amount map in Figure 13 is created from the elapsed time t from the start of measurement, distances L2 and L3, and the rotational error dθ calculated based on the placement positions of the second distance sensor 76b and the third distance sensor 76c.

[0076] The rotational error dθ is calculated, for example, from the following equation (1). As shown in Figure 11, th is the plate thickness of the side plate portion W1 of the workpiece W. hw is the distance in the Z direction between the second distance sensor 76b and the third distance sensor 76c.

[0077] dθ=arctan{(L2-(L3+th)) / hw} ···(1) In Figures 12 and 13, the horizontal axis represents the elapsed time t [sec] from the start of machining. Since the elapsed time t is correlated with the longitudinal position of the workpiece W, the horizontal axis may be replaced with the longitudinal position of the workpiece W or the rotational speed of the motor 66. The vertical axis in Figure 12 represents the Z-direction position error dz [mm], and the vertical axis in Figure 13 represents the rotational error dθ [deg], which is the rotational error of the workpiece W. The time point ts shown in Figures 12 and 13 indicates the point in time when measurement begins from one end of the workpiece W in the longitudinal direction, and the time point te indicates the point in time when the workpiece W has moved to the other end in the longitudinal direction. That is, measurement is performed as the workpiece W is fed in the longitudinal direction between time point ts and time point te. When the measurement of the workpiece W is completed at time point te, the correction amount maps shown in Figures 12 and 13 are created based on the workpiece error at each position of the workpiece W in the longitudinal direction.

[0078] The Z-direction position error dzm shown in Figure 12 is the Z-direction position error dz at the midpoint of the longitudinal direction of the workpiece W. This Z-direction position error dzm at the midpoint may be set as the reference value. The rotational direction error dθm shown in Figure 13 is the rotational direction error dθ at the midpoint of the longitudinal direction of the workpiece W. This rotational direction error dθm at the midpoint may be set as the reference value.

[0079] The machining center position correction unit 90 corrects the position and orientation of the machining center 34 based on the longitudinal position of the workpiece W and the measured distances L1, L2, and L3. Specifically, the machining center position correction unit 90 corrects the position and orientation of the machining center 34 by moving the first robot 14 and the second robot 16 according to the longitudinal position of the workpiece W, based on the correction amount map of the Z-direction position error dz and the correction amount map of the rotational direction error dθ that it has created.

[0080] Figure 14 shows the correction operation in the Z direction when grinding the upper surface SU of the upper plate portion W2 of the workpiece W. Figure 15 shows the correction operation in the rotation direction when grinding the upper surface SU of the upper plate portion W2 of the workpiece W. In Figures 14 and 15, the workpiece W shown by the dashed line represents the state when the workpiece W is in the middle position in the longitudinal direction. Correction may also be performed based on the Z direction position error dzm and rotation direction error dθm when the workpiece W is in the middle position in the longitudinal direction.

[0081] Figure 14A shows an example of the correction performed by the machining center 34 at time t1 in Figure 12. If, at time t1, the Z-direction position error dzm is smaller than the Z-direction position error dzm at time tm, which corresponds to the midpoint of the workpiece W, then the machining center 34 moves downward in the Z-direction by the difference between the Z-direction position error dz1 and the Z-direction position error dzm.

[0082] Figure 14B shows an example of the correction performed by the machining center 34 at time t2 in Figure 12. At time t2, if the Z-direction position error dz2 is greater than the Z-direction position error dzm, the machining center 34 moves upward in the Z-direction by the difference between the Z-direction position error dz2 and the Z-direction position error dzm.

[0083] Figure 15A shows an example of the correction of the rotation direction of the machining center 34 at time t1 in Figure 12. If, at time t1, the rotation direction error dθ1 is a rotation direction error dθ1 that is more counterclockwise than the rotation direction error dθm at time tm, the machining center 34 will rotate counterclockwise by the difference between the rotation direction error dθ1 and the rotation direction error dθm.

[0084] Figure 15B shows an example of the correction of the rotation direction of the machining center 34 at time t2 in Figure 12. At time t2, if the rotation direction error dθ2 is a rotation direction error dθm that is more clockwise than the rotation direction error dθm, the machining center 34 will rotate clockwise by the difference between the rotation direction error dθ2 and the rotation direction error dθm.

[0085] Similarly, when grinding the left side SL and right side SR of the side plate W1, when grinding the bottom surface SD of the bottom plate W3, when grinding the corner between the side plate W1 and the top plate W2, and when grinding the corner between the side plate W1 and the bottom plate W3, the processing machine 34 is corrected based on the created correction amount map. The method of correction is the same as when grinding the top surface SU of the top plate W2, so the explanation is omitted.

[0086] The workpiece slip detection unit 92 detects slippage of the workpiece W during machining. The workpiece slip detection unit 92 may acquire output information from the motor 66 that rotates the third roller 62 and determine whether the workpiece W is slipping based on the acquired output information. Specifically, the workpiece slip detection unit 92 may determine that the workpiece W is slipping when the output of the motor 66, i.e., the drive current value supplied to the motor 66, falls below a predetermined threshold. The threshold can be determined in advance experimentally or by design, and may be set, for example, to the upper limit of the drive current value when the workpiece W is slipping. When slippage occurs in the workpiece W, the load on the motor 66 decreases, so the drive current value decreases. Therefore, when the drive current value of the motor 66 falls below the threshold, it is possible to determine whether the workpiece W is slipping.

[0087] If slippage of the workpiece W is detected, the workpiece end measurement unit 84 detects the position of the longitudinal end of the workpiece W again. After detecting the position of the end, the motor control unit 80 controls the driving of the motor 66 during the machining of the workpiece W based on the position information of the workpiece W end detected again and the output information of the motor 66. The output information of the motor 66 includes the rotational speed of the motor 66. As a result, the driving of the motor 66 is controlled without being affected by the slippage of the workpiece W, and a decrease in machining accuracy due to the slippage of the workpiece W can be prevented.

[0088] Figure 16 is a flowchart illustrating the control operation by the control device 100 for correcting the position of the machining center 34 during machining. This flowchart corresponds to the control operation in steps S30 to S60 in the flowchart of Figure 3.

[0089] In step S110 of Figure 16, the workpiece W is fixed to the workpiece clamping device 20. In step S120, the workpiece W is moved to one and the other in the longitudinal direction, and the position of the longitudinal end of the workpiece W is measured. In step S130, while the workpiece W is fed in the longitudinal direction, the distances L1, L2, and L3 between each position of the workpiece W and each position sensor are measured along the longitudinal direction of the workpiece W using the first distance sensor 76a, the second distance sensor 76b, and the third distance sensor 76c. In step S140, the workpiece error corresponding to the longitudinal position of the workpiece W is calculated as needed based on the measured values ​​measured in step S130. In step S150, it is determined whether or not measurement has been completed at all positions in the longitudinal direction of the workpiece W. If the determination in step S150 is negative, the process returns to step S130 and the measurement and calculation of the workpiece error continue. If the determination in step S150 is positive, a correction amount map is created based on the calculated workpiece error. In step S170, the position and orientation of the machining center 34 during machining are corrected as needed so that the created correction amount map is reflected.

[0090] [Second Embodiment] In the second embodiment, the position and orientation of the machining center 150 are corrected based on encoder information of the machining center 150 obtained during machining of the workpiece W, specifically, the inclination angle β of the machining center 150 during machining. The overall arrangement of the workpiece grinding system in the second embodiment is basically the same as that of the workpiece grinding system 10 in the first embodiment. Similarly, the structure of the workpiece clamping device 20 is the same as that of the workpiece clamping device 20 in the first embodiment. In the second embodiment, the structure of the machining center 150 attached to the tip of the first robot 14 and the second robot 16 differs from that of the machining center 34 in the first embodiment described above, and the direction of correction of the position and orientation of the machining center 150 differs from that of the first embodiment.

[0091] Figure 17 shows the structure of the processing machine 150 used in the second embodiment. The processing machine 150 includes a spindle motor 152, a processing brush 154 which is a processing tool, and a constant pressure device encoder 156 built into the spindle motor 152. The processing brush 154 is rotated by the spindle motor 152. The processing machine 150 tilts as shown by the dashed line according to the pressure Pb of the head applied to the processing brush 154. The constant pressure device encoder 156 is a displacement sensor that detects the tilt angle β when the processing machine 150 is tilted from a predetermined angle as encoder information.

[0092] The constant pressure device encoder 156 has the relationships shown in Figures 18 and 19. Figure 18 shows the relationship between the head pressure Pb [Pa] applied to the machining brush 154 of the constant pressure device encoder 156 and the inclination angle β. Figure 19 shows the relationship between the head pressure Pb [Pa] applied to the machining brush 154 and the grinding amount Sg [mm]. As shown in Figure 18, the inclination angle β increases in proportion to the head pressure Pb. Also, as shown in Figure 19, the grinding amount Sg of the workpiece W increases in proportion to the head pressure Pb.

[0093] Figure 20 is a block diagram of a control device 160 corresponding to the second embodiment, which controls the workpiece grinding system 10. The control device 160 of the second embodiment includes a motor control unit 80, a robot control unit 82, a workpiece end measurement unit 84, a processing machine position correction unit 90, a workpiece slip detection unit 92, a displacement measurement unit 162, and a workpiece shape estimation unit 164. The motor control unit 80, robot control unit 82, workpiece end measurement unit 84, processing machine position correction unit 90, and workpiece slip detection unit 92 are basically the same as those of the first embodiment described above, so their explanation is omitted.

[0094] The displacement measurement unit 162 measures the displacement LD of the machining brush 154 of the machining tool 150 attached to the tip of the first robot 14 and the second robot 16 from the nominal position during the machining of the workpiece W, using a constant pressure encoder 156.

[0095] The nominal position described above is a preset reference position of the machining center 150, for example, the position shown by the solid line in Figure 17. Specifically, the nominal position is the position of the machining center 150 when no pressure Pb is applied to the machining brush 154. The inclination angle β is set to zero when the machining center 150 is in the nominal position. In reality, a small initial pressure sufficient to detect contact is applied at the nominal position, and this initial pressure is applied when the inclination angle β is zero. The displacement amount LD is calculated from the product of the tool length Lt and the inclination angle β of the machining center 150 shown in Figure 17. That is, the displacement amount LD is calculated from tool length Lt × inclination angle β. The tool length Lt is the length between the outer tip in the thickness direction of the machining brush 154 and the rotation center of the constant pressure device encoder 156. During machining of the workpiece W, the workpiece W is fed in the longitudinal direction, so the displacement measurement unit 162 measures the displacement LD along the longitudinal direction of the workpiece W during machining. Furthermore, the displacement measurement unit 162 constantly measures the displacement LD during machining of the workpiece W.

[0096] The workpiece shape estimation unit 164 estimates the shape of the workpiece W when the displacement amount at a predetermined location is measured by the displacement amount measurement unit 162. The workpiece shape estimation unit 164 estimates the shape of the workpiece W by measuring at least the displacement amounts LD1, LD2, and LD3. As shown in Figure 21, the displacement amount LD1 is the distance from the nominal position of the part Q1 being machined on the upper surface SU of the upper plate portion W2 or the lower surface SD of the lower plate portion W3 of the workpiece W. The displacement amount LD2 is the distance from the nominal position of the first part Q2 being machined on the left surface SL or the right surface SR of the side plate portion W1. The displacement amount LD3 is the distance from the nominal position of the second part Q3 being machined on the left surface SL or the right surface SR of the side plate portion W1. These are different positions from the first part Q2 and the second part Q3.

[0097] The workpiece shape estimation unit 164 estimates the shape of the workpiece W based on the longitudinal position of the workpiece W or the time t [sec] from the start of measurement, the displacement amount LD1 of the upper surface SU of the upper plate portion W2 or the lower surface SD of the lower plate portion W3 from the nominal position, the displacement amount LD2 of the second portion from the nominal position, and the displacement amount LD3 of the second portion from the nominal position. The workpiece shape estimation unit 164 estimates the shape of the workpiece W by estimating the amount of strain of the workpiece W from the time change of each measured displacement amount LD1, LD2, and LD3. The amount of strain of the workpiece W is the Y-direction position error dy of the workpiece W, the Z-direction position error dz of the workpiece W, and the rotational direction error dθ of the workpiece W. The calculation methods for the Y-direction position error dy, Z-direction position error dz, and rotational direction error dθ will be described later. Once the amount of strain of the workpiece W is estimated, the shape of the workpiece W is estimated by comparing the nominal shape of the workpiece W without strain with the amount of strain at each position in the longitudinal direction of the workpiece W. The estimated shape of the workpiece W may be a combination of multiple lines or multiple points.

[0098] Figure 21 shows the relationship between elapsed time t and displacement LD during machining of workpiece W. In Figure 21, the dashed line shows the change in displacement LD1 during machining of portion Q1 of the upper surface SU of the upper plate portion W2 of workpiece W. The dashed line shows the change in displacement LD2 during machining of the first portion Q2 of the right surface SR of the side plate portion W1. The solid line shows the change in displacement LD3 during machining of the second portion Q3 of the right surface SR of the side plate portion W1 of workpiece W. Time point ts in elapsed time t is the time when machining begins, and time point te is the time when machining in the longitudinal direction of workpiece W is completed. The ideal displacement LDX shown by the dashed line is the ideal displacement when no twisting occurs in workpiece W. For example, if the displacement LD exceeds the ideal displacement LDX, it means that workpiece W has been over-machined, and if the displacement LD is less than the ideal displacement LDX, it means that workpiece W has been under-machined. It is desirable for the displacement LD to be close to the ideal displacement LDX.

[0099] In Figure 21, the dashed line indicates portion Q1 of the upper surface SU, which is over-machined in almost all parts along the longitudinal direction of the workpiece W. The dashed line indicates the first portion Q2 of the right surface SR, which is over-machined between one end and the center of the workpiece W, and under-machined between the center and the other end. The solid line indicates the second portion Q3 of the right surface SR, which is under-machined in all parts along the longitudinal direction of the workpiece W. When the machine position correction unit 90 estimates the amount of distortion of the workpiece W from the time changes of each displacement amount LD1, LD2, and LD3, it corrects the position and orientation of the machine 150 in real time so that the displacement amount LD at each position of the workpiece W becomes the ideal displacement amount LDX, based on the estimated amount of distortion of the workpiece W, i.e., the estimated shape of the workpiece W. The position and orientation of the machine 150 are corrected when machining the next machining area.

[0100] Furthermore, when machining a third portion, which is a new part of the left side SL or right side SR of the side plate portion W1 of the workpiece W, the displacement amount LD4 from the corrected nominal position in this third portion is measured along the longitudinal direction of the workpiece W. The above corrected nominal position is a nominal position corrected based on the previously estimated shape of the workpiece W. In other words, the nominal position is updated as a corrected nominal position each time the shape of the workpiece W is estimated.

[0101] Furthermore, the workpiece shape estimation unit 164 re-estimates the shape of the workpiece W based on the newly measured displacement amount LD4 of the third part. Specifically, the workpiece shape estimation unit 164 re-estimates the shape of the workpiece W based on the previously estimated shape of the workpiece W, the displacement amount LD4 from the correction nominal position of the processing machine 150 in the third part, and the nominal shape of the workpiece W.

[0102] Once the shape of the workpiece W is estimated again, the machine position correction unit 90 updates the estimated shape of the workpiece W and corrects the position and orientation of the machine 150 when machining based on the updated shape of the workpiece W. Figure 22 shows the state when the position and orientation of the machine 150 are corrected based on the updated shape of the workpiece W. The left side of Figure 22 shows the position and orientation of the machine 150 before correction, and the right side of Figure 22 shows the position and orientation of the machine 150 after correction. As shown in Figure 22, by correcting the position and orientation of the machine 150 based on the newly updated shape of the workpiece W, the machine 150 approaches the ideal position and orientation relative to the workpiece W. As a result, the grinding amount Sg at each part of the workpiece W becomes approximately uniform, and the workpiece W is machined with high precision.

[0103] Figure 23 is a flowchart illustrating the control operation of the control device 160, which corrects the position and orientation of the machining center 150 during the machining of the workpiece W.

[0104] In step S200, the workpiece W is fixed to the workpiece clamping device 20. In step S210, the longitudinal end of the workpiece W is measured. In step S220, machining of the workpiece W begins. In step S230, the displacement LD of the machining center 150 relative to its nominal position during machining of the workpiece W is measured along the longitudinal direction of the workpiece W. In step 240, the shape of the workpiece W is estimated based on the measured displacement LD, and the shape of the workpiece W is updated accordingly. In step S250, the position and orientation of the machining center 150 are corrected based on the estimated shape of the workpiece W. In step 260, it is determined whether or not machining of all parts of the workpiece W is complete. If machining of the workpiece W is not complete, the determination in step S260 is denied, and the process returns to step S230. If machining of the workpiece W is complete, the determination in step S260 is affirmed, and machining of the workpiece W is completed.

[0105] [Calculation of Y-direction position error dy, Z-direction position error dz, and rotational error dθ] The following examples illustrate how to calculate the Y-direction position error dy, the Z-direction position error dz, and the rotational error dθ. Figure 24 shows the displacement amounts at points a, b, c, and d when the workpiece W is twisted. The dashed line represents the state where the workpiece W is not twisted, and the solid line represents the state when the workpiece W is twisted. In Figure 22, ya and za represent the y-coordinate and z-coordinate positions at point a. In Figure 22, yb and zb represent the y-coordinate and z-coordinate positions at point b. In Figure 22, yc and zc represent the y-coordinate and z-coordinate positions at point c. In Figure 22, yd and zd represent the y-coordinate and z-coordinate positions at point d.

[0106] When a straight line is rotated by an angle θ and then translated by amounts σy and σz, the z-coordinate is z' and the y-coordinate is y'. The coordinates after the translation are expressed by equations (2) and (3) below. The amount of movement σz is the amount of movement in the Z direction. The amount of movement σy is the amount of movement in the Y direction. The angle θ corresponds to the rotational error dθ in the first and second embodiments, the amount of movement σz corresponds to the Z-direction position error dz in the first and second embodiments, and the amount of movement σy corresponds to the Y-direction position error dy in the first and second embodiments.

[0107] z' = zcosθ - ysinθ + σz ··(2) y'=zsinθ-ycosθ+σy ··(3) Furthermore, at point a, due to the geometric relationship, z=za, so equations (2) and (3) become equations (4) and (5) below. Here, the position error amount da at point a is da=z'-za when y'=ya, so by removing z, we get equation (6) below.

[0108] z' = zacosθ - ysinθ + σz ··(4) y'=zasinθ-ycosθ+σy ··(5) da=z'-za=za(1 / cosθ)-za-ya(sinθ / cosθ)+σz+σy(sinθ / cosθ) ···(6) Furthermore, since y=0 at points b and c, equations (2) and (3) become equations (7) and (8) below. Here, the position error db at point b is given by equation (9) below, because when coordinate z' is coordinate zb, db=y'. Similarly, the position error dc at point c is given by equation (10) below.

[0109] z' = zcosθ + σz ··(7) y'=zsinθ+σy ··(8) db=y'=zb(sinθ / cosθ)+σz(sinθ / cosθ)+σy ···(9) dc=y'=zc(sinθ / cosθ)+σz(sinθ / cosθ)+σy ···(10) Furthermore, at point d, z=0, so equations (2) and (3) become equations (11) and (11) below. Here, the position error dd at point d is given by equation (13) below, since when coordinate x' is coordinate xd, dd=y'.

[0110] z' = -ysinθ + σz ··(11) y' = -ycosθ + σy ··(12) dd=z'=-yd(sinθ / cosθ)+σz+σy(sinθ / cosθ) ···(13) In this way, the positional error amounts at points a, b, c, and d are calculated. The rotation angle θ is calculated using points b and c. Specifically, it is calculated from equation (14) below.

[0111] θ=arctan((dc-dd) / (zc-zd)) ···(14) Furthermore, the displacements σz and σy are calculated from equations (15) and (16) below, based on points a and b. From the above, the rotation angle θ, displacement σz, and displacement σy are calculated.

[0112] σz=dacosθcosθ-dbsinθcosθ-zacosθ+zacosθsinθ+yasinθcosθ+zbsinθsinθ ·(15) σy=dasinθcosθ+dbcosθcosθ-zasinθ+zasinθcosθ+yasinθcosθ-zbsinθsinθ ·(16) Alternatively, the displacement amounts σz and σy may be calculated from equations (17) and (18) below, based on points a and c.

[0113] σz=dacosθcosθ-dcsinθcosθ-zacosθ+zacosθcosθ+yasinθcosθ+zcsinθsinθ ·(17) σy=dasinθcosθ+dccosθcosθ-zasinθ+zasinθcosθ+yasinθcosθ-zcsinθsinθ ·(18) Furthermore, although the formulas are omitted, the displacements σz and σy can also be calculated based on points b and c, or points c and d. As described above, the rotation angle θ and displacements σz and σy can be calculated based on the relational equations. While these can be calculated from the geometrical relational equations described above, they can also be calculated by other methods. For example, they can be estimated by an optimization method that repeatedly changes the amount of torsion and finds the combination of displacements σz, σy, and rotation angle θ that minimizes the error with the actual displacement.

[0114] As optimization methods, for example, the steepest descent method and Newton's method may be used. The steepest descent method is a method that proceeds to the next search point where the error is minimized based on the slope at a given point. Furthermore, by incorporating the law of inertia into the steepest descent method, oscillations near extrema may be reduced and convergence may be accelerated. Newton's method is a method that finds the Taylor expansion around a given point and sets the next search point to the minimum value of the approximation formula. Since these methods are well-known techniques, a detailed explanation will be omitted.

[0115] As described above, the first and second embodiments have been presented as examples of the technology of this disclosure. However, the technology in this disclosure is not limited thereto and can be applied to embodiments that have been modified, replaced, added, or omitted. Furthermore, it is possible to combine the components described in the above-mentioned embodiments to create new embodiments. Therefore, examples of modifications are given below.

[0116] [Differentiation] In the above embodiment, the sliding mechanism 70 was attached to the first roller 58, but the sliding mechanism 70 may be attached to the second roller 60, and the distance between the first roller 58 and the second roller 60 may be increased and decreased.

[0117] In the above embodiment, the third roller 62 was in contact with the left side surface SL of the side plate W1 and the fourth roller 64 was in contact with the right side surface SR of the side plate W1. However, the third roller 62 may be in contact with the right side surface SR of the side plate W1 and the fourth roller 64 may be in contact with the left side surface SL of the side plate W1.

[0118] In the above embodiment, the lower end of the third roller 62 was located below the lower end of the fourth roller 64, but the lower end of the fourth roller 64 may also be located below the lower end of the third roller 62.

[0119] In the above embodiment, the crossbeam 18 was positioned in the space between the first clamp arm 50A and the second clamp arm 50B, and the first clamp arm 50A and the second clamp arm 50B were connected to the crossbeam 18 via an intermediate member 45. However, the disclosure is not limited thereto. For example, the crossbeam 18 may be connected only to the second clamp arm 50B. In this case, the first clamp arm 50A is unnecessary. Thus, the structure for fixing the workpiece support member 40 to the crossbeam 18 may be modified as appropriate.

[0120] In the above embodiment, the workpiece W had a Z-shaped cross-section, but this disclosure is not limited to a Z-shaped cross-section. This disclosure can also be applied to workpieces W with C-shaped, I-shaped, and H-shaped cross-sections. Furthermore, the number of rollers may be changed depending on the cross-sectional shape of the workpiece W.

[0121] In the above embodiment, the workpiece W before processing, held in the first stocker 22, is transferred to the workpiece clamping device 20 by the first robot 14, and the workpiece W after processing is transferred to the second stocker 24 by the second robot 16. However, this disclosure is not limited thereto. Specifically, the workpiece W after processing may be transferred to the second stocker 24 by the first robot 14, or the workpiece W after processing may be transferred to the first stocker 22 by the first robot 14, or the workpiece W after processing may be transferred to the first stocker 22 by the second robot 16.

[0122] In the above embodiment, the work clamping device 20 was equipped with three work support members: a first work support member 40, a second work support member 42, and a third work support member 44. However, it may be equipped with two work support members, or four or more work support members. In other words, the work clamping device only needs to be equipped with at least two work support members.

[0123] In the above embodiment, the motor 66 was connected to the third roller 62, but instead of the third roller 62, the motor 66 may be connected to any of the first roller 58, the second roller 60, and the fourth roller 64, and the roller connected to the motor 66 may be driven. Alternatively, at least two of the first roller 58, the second roller 60, the third roller 62, and the fourth roller 64 may be driven by the motor 66.

[0124] In the above embodiment, the slide mechanism 70 was an air cylinder, but it may also be a hydraulic cylinder, a ball screw mechanism, or an electrically operated slide such as a linear motor. In other words, the slide mechanism 70 only needs to have a structure that can move the first roller 58.

[0125] In the above embodiment, when processing the workpiece W, the processing area of ​​the workpiece W was divided into a first to third area, and processing of the workpiece W was performed in each area. However, the number of processing areas of the workpiece W is not limited to three. For example, the processing area of ​​the workpiece W may be divided into two areas, or into four or more processing areas. Alternatively, the processing area of ​​the workpiece W does not necessarily have to be divided.

[0126] In the first embodiment described above, the Z-direction position, Y-direction position, and rotational orientation of the processing machine 34 were corrected. However, it is also possible to correct only one of the Z-direction position, Y-direction position, or orientation of the processing machine 34. When correcting the Z-direction position and Y-direction position of the processing machine 34, for example, the position of the processing machine 34 is corrected based on a distance L1 measured by the first distance sensor 76a and a distance L2 measured by the second distance sensor 76b. Alternatively, the position of the processing machine 34 may be corrected based on a distance L3 measured by the third distance sensor 76c instead of distance L2. Furthermore, when correcting the orientation of the processing machine 34, the orientation of the processing machine 34 may be corrected based on a distance L2 measured by the second distance sensor 76b and a distance L3 measured by the third distance sensor 76c.

[0127] In the above embodiment, the first stocker 22 and the second stocker 24 were arranged adjacent to the processing chamber 12, but the first stocker 22 and the second stocker 24 may be arranged inside the processing chamber 12.

[0128] In the above embodiment, the first panel 28A was placed between the first column 26A and the second column 26B, but instead of the first panel 28A, a wire mesh may be placed, or a column may be placed between the first column 26A and the second column 26B. Similarly, instead of the second panel 28B placed between the third column 26C and the fourth column 26D, a wire mesh may be placed, or a column may be placed between the third column 26C and the fourth column 26D.

[0129] In the above embodiment, the first shutter 30A was positioned between the first column 26A and the third column 26C, but the first shutter may be omitted. Similarly, the second shutter 30B, positioned between the second column 26B and the fourth column 26D, may be omitted.

[0130] In the above embodiment, the position of the longitudinal end of the workpiece W was measured by moving the workpiece W in the longitudinal direction to a position where the first end detection sensor 72 could not detect the workpiece W. However, the position of the end of the workpiece W may also be measured by outputting a signal from the first end detection sensor 72 indicating the detection of the end of the workpiece W when the workpiece W is moved in the longitudinal direction to a position where the first end detection sensor 72 can detect the workpiece W.

[0131] In the above embodiment, the motor 66 was stopped after the longitudinal position of the workpiece W reached the end of the machining area of ​​the workpiece W, and after the machining center 34 moved to the next machining position, the motor 66 was rotated to feed the workpiece W in the longitudinal direction. However, the machining center 34 may be moved to the machining position while the motor 66 is rotating.

[0132] The functions of the elements disclosed herein may be implemented using one or more circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), FPGAs (Field Programmable Gate Arrays), conventional circuits, and / or combinations thereof, which are programmed using one or more programs stored in one or more memories, or otherwise configured to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuits. A processor may be a programmed processor that executes programs stored in memory. In this disclosure, a circuit, unit, or means is hardware that performs the enumerated functions individually or in combination with each other, or hardware programmed to perform the enumerated functions individually or in combination with each other. Hardware may be any hardware disclosed herein that is programmed or configured to perform the enumerated functions. Computer programs, including computer instructions, are stored in memory. These computer instructions provide logic and routines that enable hardware (e.g., a processing circuit or circuit) to perform the methods disclosed herein. This computer program can be implemented in known formats on computer-readable storage media, computer program products, memory devices, storage media such as CD-ROMs or DVDs, and / or in the memory of FPGAs or ASICs.

[0133] [Summary of this disclosure] A first aspect of the present disclosure is a work clamping device for clamping a longitudinal workpiece when processing the workpiece, the work clamping device comprising at least two spaced work support members, an end detection sensor for detecting the end of the workpiece, and a control device, each of the work support members having a plurality of rollers and a motor that rotates at least one of the plurality of rollers to feed the workpiece in the direction of rotation of the roller, the control device controls the driving of the motor during processing of the workpiece based on position information of the longitudinal end of the workpiece detected by the end detection sensor and output information of the motor.

[0134] According to the first embodiment described above, the end detection sensor detects the position information of the longitudinal end of the workpiece, and the motor drive is controlled based on the position information of the longitudinal end of the workpiece and the motor output information. By determining the longitudinal position of the workpiece during processing from the position information of the longitudinal end of the workpiece and the motor output information, the workpiece can be processed with high precision.

[0135] A work clamping device according to a second embodiment is preferably further characterized in the work clamping device according to a first embodiment. That is, in the work clamping device according to a second embodiment, the work clamping device further comprises a crossbeam, and the work support member supports the plurality of rollers and includes a roller support member that protrudes downward from the crossbeam.

[0136] According to the second embodiment, the workpiece is clamped using a plurality of rollers supported by roller support members protruding downward from the crossbeam, and the workpiece is suspended, thereby facilitating processing of the workpiece by a processing machine.

[0137] The work clamping device according to the third embodiment preferably further comprises the following features in addition to the work clamping device according to the first or second embodiment. In other words, in the work clamping device according to the third embodiment, the work has an upper surface, a lower surface, a left surface, and a right surface extending in the longitudinal direction of the work, the work support member has a slide mechanism and a roller support member that supports the slide mechanism, the plurality of rollers include a first roller that abuts the upper surface and rotates around a first axis, a second roller positioned below the first roller and abutting the lower surface and rotating around a second axis, a third roller positioned below the first roller and above the second roller and abutting either the left surface or the right surface and rotating around a third axis, and a fourth roller positioned below the first roller and above the second roller, and spaced apart from the third roller in the left-right direction, abutting the other of the left surface or the right surface and rotating around a fourth axis parallel to the third axis, the slide mechanism moves the first roller or the second roller in a direction perpendicular to the first axis, and moves the first roller and the second roller apart and closer together.

[0138] According to the third embodiment, when processing a workpiece, the sliding mechanism is moved so as to press the first roller or the second roller against the upper or lower surface of the workpiece, thereby allowing the workpiece to be fed while conforming to any shape errors.

[0139] A work clamping device according to the fourth embodiment preferably has the following additional features in addition to being a work clamping device according to any of the first to third embodiments: that is, in the work clamping device according to the fourth embodiment, the lower end of the third roller is located below the lower end of the fourth roller.

[0140] According to the fourth embodiment, the left and right sides of the workpiece are properly held by the third and fourth rollers, thereby balancing the moment of the workpiece.

[0141] A work clamping device according to the fifth embodiment preferably has the following additional features in addition to a work clamping device according to any of the first to fourth embodiments. That is, in the work clamping device according to the fifth embodiment, the control device determines that there has been slippage of the workpiece when the output of the motor falls below a predetermined threshold.

[0142] According to the fifth embodiment, the slippage of the workpiece can be accurately determined based on the output of the motor.

[0143] A work clamp device according to the sixth embodiment preferably has the following additional features in addition to being a work clamp device according to any of the first to fifth embodiments. That is, in the work clamp device according to the sixth embodiment, the control device includes a detection unit for detecting slippage of the workpiece, and when the detection unit detects slippage of the workpiece, the control device rotates the motor to feed the workpiece until the end of the workpiece passes the position of the end detection sensor, and controls the driving of the motor during processing of the workpiece based on the end of the workpiece detected again by the end detection sensor and the output information of the motor.

[0144] According to the sixth embodiment, if workpiece slippage is detected, the edge of the workpiece is detected again and the workpiece is machined, thereby eliminating the reduction in machining accuracy due to workpiece slippage.

[0145] A work clamp device according to the seventh embodiment preferably has the following additional features in addition to a work clamp device according to any of the first to sixth embodiments. That is, in the work clamp device according to the seventh embodiment, the roller support member includes a first roller support member that supports the first roller and the fourth roller, and a second roller support member that supports the second roller and the third roller, wherein the first roller support member and the second roller support member move in directions of moving apart from each other and moving toward each other.

[0146] According to the seventh embodiment, when holding a workpiece with the roller support member, the workpiece can be placed inside the roller support member by separating the first roller support member and the second roller support member. Similarly, when removing a workpiece held by the roller support member, the workpiece can be removed from the roller support member by separating the first roller support member and the second roller support member.

[0147] A workpiece processing method according to the eighth aspect comprises a workpiece clamping device including a plurality of rollers, a motor for rotating at least one of the rollers, and an end detection sensor for detecting the end of a longitudinal workpiece, wherein the workpiece is processed by a processing machine while the workpiece is held by the workpiece clamping device, and the workpiece processing method includes, before the start of processing by the processing machine, detecting one end of the longitudinal workpiece with the end detection sensor by rotating the rollers to feed out the workpiece, processing the workpiece with the processing machine while feeding out the longitudinal workpiece by rotating the rollers, and controlling the drive of the motor during processing of the workpiece based on position information of the longitudinal end of the workpiece and output information of the motor.

[0148] According to the eighth aspect, when processing a workpiece with a processing machine while feeding out a longitudinal workpiece by rotating a roller, the position information of the longitudinal end of the workpiece is detected by an end detection sensor, and the motor drive is controlled based on the position information of the longitudinal end of the workpiece and the motor output information. By determining the longitudinal position of the workpiece during processing from the position information of the longitudinal end of the workpiece and the motor output information, the workpiece can be processed with high precision.

[0149] A workpiece processing method according to the ninth embodiment is preferably further characterized in the workpiece processing method according to the eighth embodiment. That is, in the workpiece processing method according to the ninth embodiment, when processing the workpiece with the processing machine, the workpiece is fed out by the workpiece clamping device while the processing machine is immobilized with respect to the longitudinal direction of the workpiece.

[0150] According to the ninth embodiment, by feeding the workpiece using a workpiece clamping device while the machining machine is stationary, the machining accuracy of the workpiece is improved compared to when the machining machine is moved during machining.

[0151] A workpiece processing method according to the tenth embodiment is preferably further characterized in the workpiece processing method according to the eighth or ninth embodiment. That is, in the workpiece processing method according to the tenth embodiment, the workpiece processing method further includes detecting slippage of the workpiece, and detecting slippage of the workpiece includes acquiring output information of the motor that rotates the roller, and determining whether or not slippage has occurred in the workpiece based on the output information of the motor.

[0152] According to the tenth embodiment, the slippage of the workpiece can be accurately determined based on the motor output information.

[0153] The workpiece processing method according to the 11th embodiment is preferably further characterized in that it is a workpiece processing method according to any of the 8th to 10th embodiments. That is, in the workpiece processing method according to the 11th embodiment, it is determined that there has been slippage of the workpiece when the output of the motor falls below a predetermined threshold.

[0154] According to the eleventh embodiment, the slippage of the workpiece can be easily determined by comparing the motor output with a threshold value.

[0155] A workpiece processing method according to the 12th embodiment is preferably further characterized in any of the workpiece processing methods according to the 8th to 11th embodiments. Specifically, a workpiece processing method according to the 12th embodiment further includes, when it is determined that the workpiece has slipped, feeding the workpiece with the roller and re-detecting the longitudinal end of the workpiece, and controlling the drive of the motor during workpiece processing based on the position information of the re-detected end of the workpiece and the output information of the motor.

[0156] According to the twelfth embodiment, if slippage of the workpiece is detected, the workpiece can be machined with high precision by detecting the end of the workpiece again and then performing the machining, using the positional information of the workpiece end that has been detected again.

[0157] The workpiece processing method according to the 13th embodiment is preferably a workpiece processing method according to any of the 8th to 12th embodiments, further comprising the following features: that is, the workpiece processing method according to the 13th embodiment includes transferring the workpiece from a first stocker that holds the workpiece before processing to the workpiece clamping device by one of two robots; processing the workpiece by the two robots after attaching the processing machine to the two robots; and transferring the processed workpiece to a second stocker that holds the workpiece after processing by one or the other of the two robots.

[0158] According to the 13th embodiment, since workpiece transport and workpiece processing are performed by two robots, workpiece processing and workpiece transport can be performed in a small layout.

[0159] The workpiece processing method according to the 14th embodiment is preferably a workpiece processing method according to any of the 8th to 13th embodiments, further comprising the following features. That is, in the workpiece processing method according to the 14th embodiment, the workpiece has an upper surface, a lower surface, a left surface, and a right surface extending in the longitudinal direction, and the workpiece processing method further includes correcting the position of the processing machine, the correction of the position of the processing machine includes measuring the distance between the first distance sensor and the upper surface or the lower surface along the longitudinal direction of the workpiece using a first distance sensor that measures the distance to the workpiece while the roller is rotated to feed out the workpiece, measuring the distance between the second distance sensor and a first portion of the left surface or the right surface along the longitudinal direction of the workpiece using a second distance sensor that measures the distance to the workpiece while the roller is rotated to feed out the workpiece, and correcting the position of the processing machine when processing the workpiece based on the position of the workpiece or the time from the start of measurement, the measured distance between the first distance sensor and the upper surface or the lower surface, and the measured distance between the second distance sensor and the first portion of the left surface or the right surface.

[0160] According to the 14th embodiment, the processing machine can be corrected to an appropriate position according to the orientation of the workpiece based on the position of the workpiece or the time since the start of measurement, the distance between the first distance sensor and the top or bottom surface, and the distance between the second distance sensor and the left or right surface.

[0161] A workpiece processing method according to the 15th embodiment is preferably a workpiece processing method according to any of the 8th to 14th embodiments, further comprising the following features: that is, a workpiece processing method according to the 15th embodiment further includes correcting the posture of the processing machine, the correction of the posture of the processing machine includes measuring the distance between the third distance sensor and a second portion of the left or right surface that is different from the first portion of the workpiece, along the longitudinal direction of the workpiece, using a third distance sensor that measures the distance to the workpiece, and correcting the posture of the processing machine when processing the workpiece based on the position of the workpiece or the time since the start of measurement, the measured distance between the second distance sensor and the first portion of the left or right surface, and the measured distance between the third distance sensor and the second portion of the left or right surface.

[0162] According to the 15th embodiment, the processing machine can be corrected to an appropriate posture according to the posture of the workpiece based on the position of the workpiece or the time since the start of measurement, the distance between the second distance sensor and the first part of the left or right side, and the distance between the third distance sensor and the second part of the right or left side.

[0163] A workpiece processing method according to the 16th embodiment is preferably a workpiece processing method according to any of the 8th to 13th embodiments, further comprising the following features: In the workpiece processing method according to the 16th embodiment, the workpiece has an upper surface, a lower surface, a left surface, and a right surface extending in the longitudinal direction of the workpiece, and the workpiece processing method further includes correcting the position and orientation of the processing machine, wherein the position and orientation of the processing machine is corrected by measuring the displacement of the processing tool on the upper surface or the lower surface from the nominal position along the longitudinal direction of the workpiece using a displacement sensor that measures the displacement of the processing tool positioned at the tip of the processing machine from the nominal position while the roller is rotated to feed the workpiece, and by measuring the displacement of the processing tool on the first portion of the left surface or the right surface from the nominal position along the longitudinal direction of the workpiece using the displacement sensor while the roller is rotated to feed the workpiece. The method includes: rotating the roller to feed out the workpiece, measuring the displacement of the processing tool from the nominal position on the second portion of the left or right surface using the displacement sensor along the longitudinal direction of the workpiece; estimating the shape of the workpiece based on the position of the workpiece or the time since the start of measurement, the measured displacement of the processing tool from the nominal position on the top or bottom surface, the measured displacement of the processing tool from the nominal position on the first portion of the left or right surface, the measured displacement of the processing tool from the nominal position on the second portion of the left or right surface, and the nominal shape of the workpiece; and correcting the position and orientation of the processing machine when processing the workpiece based on the estimated shape of the workpiece.

[0164] According to the 16th embodiment, the shape of the workpiece is estimated based on the workpiece position or time from the start of measurement, the displacement of the machining tool from the nominal position on the top or bottom surface, the displacement of the machining tool from the nominal position on the first part of the left or right surface, the displacement of the machining tool from the nominal position on the second part of the left or right surface, and the nominal shape of the workpiece. The position and orientation of the machining center are then corrected based on the estimated shape of the workpiece. This enables the workpiece to be machined with high precision.

[0165] A workpiece processing method according to the 17th embodiment is preferably the workpiece processing method according to the 16th embodiment, further comprising the following features. That is, in the workpiece processing method according to the 17th embodiment, when the nominal position corrected based on the previously estimated shape of the workpiece is taken as the corrected nominal position, correcting the position and orientation of the processing machine further includes, while rotating the roller to feed out the workpiece, measuring the amount of displacement of the processing tool from the corrected nominal position in the third portion other than the second portion of the left or right surface along the longitudinal direction of the workpiece using the displacement sensor; re-estimating the shape of the workpiece based on the previously estimated shape of the workpiece, the measured amount of displacement of the processing tool from the corrected nominal position in the third portion, and the nominal shape of the workpiece; and correcting the position and orientation of the processing machine when processing based on the re-estimated shape of the workpiece.

[0166] According to the 17th embodiment, the nominal position corrected based on the previously estimated workpiece shape is set as the corrected nominal position, the workpiece shape is re-estimated based on the previously estimated workpiece shape, the amount of displacement of the machining tool in the third part from the corrected nominal position, and the nominal shape of the workpiece, and the position and orientation of the machining center are corrected based on the re-estimated workpiece shape. As a result, the position and orientation of the machining center are always updated to the appropriate position, so that the workpiece can be machined with high precision.

[0167] A workpiece transfer system according to the 18th embodiment comprises a first robot and a second robot, each having an end effector at its tip; a workpiece clamping device according to claim 1, disposed between the support bases of the first robot and the second robot, and supporting a workpiece; a first stocker, installed on the opposite side of the workpiece clamping device with the first robot in between, and located within the reach of the end effector of the first robot; and a second stocker, installed on the opposite side of the workpiece clamping device with the second robot in between, and located within the reach of the end effector of the second robot.

[0168] According to the 18th embodiment, workpieces can be transported in a small layout by using a first robot and a second robot positioned on either side of a workpiece clamping device to transport the workpieces between the first stocker, the workpiece clamping device, and the second stocker. [Explanation of symbols]

[0169] 14: First Robot 16: Second Robot 18: Horizontal beam 20: Workpiece clamping device 22: First Stocker 24: Second Stocker 32: Hand 34: Processing machine 40: First workpiece support member 42: Second workpiece support member 44: Third workpiece support member 55: Roller support member 55A: First roller support member 55B: Second roller support member 58: First Laura 60: Second Rotor 62: Third Laura 64: Fourth Laura 66: Motor 70: Sliding mechanism 72: First end detection sensor 74: Second end detection sensor 76a: First distance sensor 76b: Second distance sensor 76c: Third distance sensor 100: Control device 150: Processing machine 154: Processing brush 156: Constant pressure device encoder 160: Control device W: Work

Claims

1. A workpiece clamping device for clamping a workpiece when processing a long, rectangular workpiece, The aforementioned work clamp device is At least two workpiece support members are installed at intervals, An end detection sensor for detecting the end of the workpiece, A control device is provided, Each of the aforementioned workpiece support members is Multiple rollers, The system includes a motor that rotates at least one of the plurality of rollers to move the workpiece in the direction of rotation of the roller, The control device is A workpiece clamping device that controls the drive of the motor during machining of the workpiece based on the position information of the longitudinal end of the workpiece detected by the end detection sensor and the output information of the motor.

2. The aforementioned work clamping device further comprises a crossbeam, The aforementioned workpiece support member is The work clamping device according to claim 1, further comprising a roller support member that supports the plurality of rollers and protrudes downward from the crossbeam.

3. The workpiece has an upper surface, a lower surface, a left surface, and a right surface extending in the longitudinal direction of the workpiece. The workpiece support member comprises a sliding mechanism and a roller support member that supports the sliding mechanism. The aforementioned multiple rollers A first roller that contacts the upper surface and rotates around the first axis, A second roller is positioned below the first roller, contacts the lower surface, and rotates around the second axis, A third roller is positioned below the first roller and above the second roller, contacts either the left or right surface, and rotates around the third axis, The system includes a fourth roller positioned below the first roller and above the second roller, spaced apart from the third roller in the left-right direction, in contact with the other of the left or right surface, and rotating around a fourth axis parallel to the third axis, The work clamping device according to claim 1 or 2, wherein the sliding mechanism moves the first roller or the second roller in a direction perpendicular to the first axis, and moves the first roller and the second roller apart and closer to each other.

4. The workpiece clamping device according to claim 3, wherein the lower end of the third roller is located below the lower end of the fourth roller.

5. The workpiece clamping device according to claim 1, wherein the control device determines that the workpiece has slipped when the output of the motor falls below a predetermined threshold.

6. The control device includes a detection unit for detecting the slippage of the workpiece, The workpiece clamping device according to claim 5, wherein the control device, when the detection unit detects slippage of the workpiece, rotates the motor to move the workpiece until the end of the workpiece passes the position of the end detection sensor, and controls the drive of the motor during processing of the workpiece based on the end of the workpiece detected again by the end detection sensor and the output information of the motor.

7. The roller support member is A first roller support member that supports the first roller and the fourth roller, The system includes a second roller support member that supports the second roller and the third roller, The workpiece clamping device according to claim 3, wherein the first roller support member and the second roller support member move in directions toward and toward each other.

8. A workpiece machining method comprising a workpiece clamping device including a plurality of rollers, a motor for rotating at least one of the rollers, and an end detection sensor for detecting the end of a longitudinal workpiece, wherein the workpiece is machined by a machining machine while the workpiece is held by the workpiece clamping device, The method for machining the aforementioned workpiece is: Before processing begins using the aforementioned processing machine, the roller is rotated to feed out the workpiece, thereby detecting one end of the workpiece in the longitudinal direction with the end detection sensor. The process involves rotating the roller to feed out the longitudinally shaped workpiece while processing it with the processing machine, A method for machining a workpiece, comprising controlling the drive of the motor during machining of the workpiece based on positional information of the longitudinal end of the workpiece and output information of the motor.

9. The method for processing a workpiece according to claim 8, wherein when processing the workpiece with the processing machine, the workpiece is fed out by the workpiece clamping device while the processing machine is immobilized with respect to the longitudinal direction of the workpiece.

10. The method for processing the workpiece further includes detecting slippage of the workpiece. Detecting the slippage of the aforementioned workpiece is To acquire output information of the motor that rotates the roller, A method for machining a workpiece according to claim 8 or 9, comprising determining whether or not the workpiece is slipping based on the output information of the motor.

11. The method for machining a workpiece according to claim 10, wherein it is determined that the workpiece has slipped when the output of the motor falls below a predetermined threshold.

12. The method for machining the aforementioned workpiece is: If it is determined that the workpiece has slipped, the workpiece is fed out by the roller and the longitudinal end of the workpiece is detected again. The method for machining a workpiece according to claim 11, further comprising controlling the drive of the motor during machining of the workpiece based on the position information of the end of the workpiece detected again and the output information of the motor.

13. The method for machining the aforementioned workpiece is: One of the two robots transfers the workpiece from the first stocker, which holds the workpiece before processing, to the workpiece clamping device. After attaching the processing machine to the two robots, the workpiece is processed by the two robots. A method for processing a workpiece according to claim 8 or 9, comprising transferring the processed workpiece to a second stocker that holds the processed workpiece using one or the other of the two robots.

14. The workpiece has an upper surface, a lower surface, a left surface, and a right surface extending in the longitudinal direction. The method for machining the workpiece further includes correcting the position of the machining machine, Correcting the position of the aforementioned processing machine is While the roller is rotated to feed out the workpiece, a first distance sensor measures the distance between the first distance sensor and the upper or lower surface along the longitudinal direction of the workpiece. While the roller is rotated to feed out the workpiece, a second distance sensor measures the distance between the second distance sensor and the first portion of the left or right side of the workpiece along the longitudinal direction of the workpiece. A method for machining a workpiece according to claim 8 or 9, comprising correcting the position of the machining machine during machining based on the position of the workpiece or the time since the start of measurement, the measured distance between the first distance sensor and the upper surface or the lower surface, and the measured distance between the second distance sensor and the first portion of the left surface or the right surface.

15. The method for processing the workpiece further includes correcting the orientation of the processing machine, Correcting the orientation of the aforementioned processing machine is A third distance sensor measures the distance to the workpiece, and measures the distance between the third distance sensor and a second portion of the left or right surface that is different from the first portion, along the longitudinal direction of the workpiece. A method for machining a workpiece according to claim 14, comprising correcting the orientation of the machining machine during machining based on the position of the workpiece or the time since the start of measurement, the measured distance between the second distance sensor and the first portion of the left or right surface, and the measured distance between the third distance sensor and the second portion of the left or right surface.

16. The workpiece has an upper surface, a lower surface, a left surface, and a right surface extending in the longitudinal direction of the workpiece. The method for processing the workpiece further includes correcting the position and orientation of the processing machine, Correcting the position and orientation of the aforementioned processing machine is While the roller is rotated to feed the workpiece, a displacement sensor that measures the displacement of the processing tool positioned at the tip of the processing machine from its nominal position measures the displacement of the processing tool from its nominal position along the longitudinal direction of the workpiece, and While rotating the roller to feed the workpiece, the displacement sensor measures the amount of displacement of the machining tool from the nominal position on the first portion of the left or right surface along the longitudinal direction of the workpiece. While rotating the roller to feed the workpiece, the displacement sensor measures the amount of displacement of the machining tool from the nominal position on the second portion of the left or right side of the workpiece along the longitudinal direction of the workpiece. The shape of the workpiece is estimated based on the position of the workpiece or the time since the start of measurement, the measured displacement of the machining tool from the nominal position on the upper or lower surface, the measured displacement of the machining tool from the nominal position on the first portion of the left or right surface, the measured displacement of the machining tool from the nominal position on the second portion of the left or right surface, and the nominal shape of the workpiece. A method for machining a workpiece according to claim 8 or 9, comprising correcting the position and orientation of the machining machine during machining based on the estimated shape of the workpiece.

17. When the nominal position corrected based on the previously estimated shape of the workpiece is taken as the corrected nominal position, correcting the position and orientation of the machining center is: While rotating the roller to feed the workpiece, the displacement sensor measures the amount of displacement of the machining tool from the correction nominal position in the third portion other than the second portion of the left or right surface along the longitudinal direction of the workpiece. Based on the previously estimated shape of the workpiece, the measured displacement of the machining tool from the correction nominal position in the third portion, and the nominal shape of the workpiece, the shape of the workpiece is estimated again. The method for machining a workpiece according to claim 16, further comprising correcting the position and orientation of the machining machine during machining based on the shape of the workpiece estimated again.

18. A first robot and a second robot equipped with an end effector at their tip, A workpiece clamping device according to claim 1, which is positioned between the support bases of the first robot and the second robot and supports a workpiece, A first stocker is installed on the opposite side of the first robot from the work clamping device and is positioned within the reach of the end effector of the first robot, A workpiece transfer system comprising: a second stocker positioned on the opposite side of the workpiece clamping device with the second robot in between, and positioned within the reach of the end effector of the second robot.

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