JP5866183B2 - Method for supplying rectangular workpieces loaded unaligned to a bending machine - Google Patents

Description

  The present invention relates to a method of supplying rectangular workpieces stacked without being aligned to a bending machine.

  In the case where a rectangular workpiece is supplied to the bending machine by the robot, for example, when the rectangular workpiece W loaded on the loading device 201 is sucked and held by the robot hand 203 as shown in FIG. In addition, when the stacked rectangular workpieces W have different directions and the distances A to D from the end of the rectangular workpiece W of the vacuum pad 205 are greatly different, a suction error occurs or a bending machine The position of the bending mold and the workpiece W may be shifted at the time of positioning for contact with the back gauge.

  For this reason, it is necessary to load the workpieces W on the loading device 201 in an aligned manner, and there is a problem that the number of work steps for that purpose increases.

  Further, there is a case where two or more workpieces W are simultaneously attracted by the robot hand. As a means for preventing this, there is a magnet floater 207 as shown in FIG. 30, for example. However, when the magnet floater 207 is used, it is not possible to prevent two sheets from being taken unless the ends of the stacked rectangular workpieces W are aligned. Further, as shown in FIG. 31, an air blow device 209 is used in combination to prevent two pieces from being taken in the magnet floater 207 (Patent Document 1). There is a problem that it is not possible to prevent the removal of two sheets because of no effect.

  Further, as shown in FIG. 32, a cylinder support frame 302 provided on the suction pad support arm 301 is provided with an advance / retreat cylinder 303 so as to be swingable. There is a method (Patent Document 2) in which the end portion of the workpiece W is prevented by a “turning operation” with a suction pad 307 provided on the hollow shaft body 306 that is swung as described above. The rectangular workpiece W to be supplied also has many shapes having notches 311 at four corners as shown in FIG. 33, and the suction pad 307 must avoid the notches 311. It must move for each shape, and the “turning operation” cannot be used efficiently.

JP 2002-361585 A JP 2001-122456 A

  The present invention has been made to solve the above-described problems, and the problem of the present invention is that it is not necessary to align and stack rectangular workpieces on the loading device, and even when two sheets are taken, To provide a rectangular workpiece supply method to a bending machine capable of reliably separating a workpiece into a single sheet by using a suction means and a gripping device of a robot hand.

As a means for solving the above-mentioned problem, the method for supplying a rectangular work material stacked in an unaligned manner according to claim 1 to a bending machine is a robot equipped with a robot hand equipped with a plurality of suction means. And a workpiece bending system with a loading device including a CAM computer, a loading posture measuring means and a plate thickness measuring means, and a workpiece gripping device. To do.
1. Measuring points suitable for measuring the loading posture of the workpiece loaded on the loading device by automatically detecting the straight line of the workpiece contour from the graphic data of the bent product input to the CAM computer As described above, measurement points are set at positions including straight portions of all the Y-axis reference sides and the X-axis reference sides of the plurality of workpieces .
2 . From the measurement data obtained by the loading posture measuring means, a straight line expression representing the Y axis reference side of the uppermost workpiece loaded on the loading device and a straight line expression representing the X axis reference side are obtained, and the Y axis The inclination α of the reference side with respect to the X axis and a new origin coordinate O ′ (x, y) are calculated and obtained.
3 . Based on the inclination α with respect to the X-axis of the Y-axis reference side obtained in step 1 and the new origin coordinates O ′ (x, y), the gripping posture of the robot hand is corrected and the workpiece is sucked and held, The plurality of suction means of the robot hand are individually moved up and down to drop the second and subsequent workpieces to the loading device.
4 . The plate thickness of the workpiece held by the suction unit is measured by the plate thickness measuring unit.
5 . When it is detected in step 4 that a plurality of workpieces are sucked and held, the plurality of workpieces held by suction are conveyed to the gripping device to temporarily hold the workpiece. Then, the uppermost layer of the workpiece temporarily held in the gripping device is sucked and held one by one from the uppermost layer and returned and loaded onto the loading device.
6 . Steps 1 to 4 are performed on the workpieces returned and loaded.
7 . When it is detected in step 4 that a plurality of workpieces are not held by suction, the workpieces are supplied to a bending machine.

  The method for supplying unfolded workpieces to the folding machine according to claim 2 is the same as the method for supplying unfolded workpieces to the folding machine according to claim 1. In the supply method, the stacking posture measuring means captures an outline of the workpiece by an optical cutting method using laser slit light, and scans the workpiece with the laser slit light to thereby detect the X axis of the workpiece. The gist is to detect the direction and the end surface position in the Y-axis direction.

  The supply method to the bending machine of the rectangular workpieces loaded unaligned according to claim 3 is the method of supplying a bending material to the bending machine according to claim 1, wherein The loading posture measuring means is provided with a pair of measuring heads equipped with a laser displacement meter so that they can be moved and positioned in the three axial directions of X, Y and Z, and the displacement of the upper surface of the workpiece is detected by the laser displacement meter. Thus, the gist is to detect the end face positions of the workpiece in the X-axis direction and the Y-axis direction.

  According to the work material supply method to the bending machine of the present invention, when the work material loaded on the loading device is sucked and held by the robot hand, the loading is performed even if the work materials are not aligned and loaded. The displacement of the loading position relative to the positioning reference position of the workpiece at the top of the device is measured, and the gripping posture of the robot hand is corrected and held by suction. It is possible to prevent the deviation of the bending position at the time.

  Also, when the robot hand sucks two or more workpieces at the same time, it uses a robot hand suction means and a gripping device to reliably separate the workpieces into one, and then the bending machine Can be supplied to.

  Further, since the work pieces do not have to be aligned and stacked on the loading device, the number of work steps for aligning and loading is reduced, so that the processing cost of the bending process is reduced.

Explanatory drawing of the workpiece bending process system in the workpiece supply method to the bending machine which concerns on this invention. Explanatory drawing (overall perspective view) of a loading apparatus. The enlarged view (front side) of the three-dimensional laser sensor part in FIG. The enlarged view (back side) of the three-dimensional laser sensor part in FIG. Explanatory drawing (whole perspective view) of the measurement range of a loading apparatus. Explanatory drawing (plan view) of the measurement range of the loading apparatus. Explanatory drawing (rear side view) of the measurement range of a loading apparatus. Explanatory drawing of measurement range of loading device (left side view of FIG. 6) Explanatory drawing of the measurement principle of a three-dimensional laser sensor. The figure explaining the measurement operation | movement condition of a three-dimensional laser sensor. The analysis figure of the measurement result by a three-dimensional laser sensor. It is explanatory drawing of the outline | summary of the adsorption | suction means of a robot hand, (a) is a top view, (b) shows a side view. Explanatory drawing of the wave | undulation operation | movement of the adsorption | suction means of a robot hand. Explanatory drawing of 2 sheet picking prevention operation | movement which concerns on this invention. Explanatory drawing (procedure 1) of 2 sheet picking prevention operation which concerns on this invention. Explanatory drawing (procedure 2) of 2 sheet picking prevention operation | movement which concerns on this invention. Explanatory drawing (procedure 3) of 2 sheet picking prevention operation which concerns on this invention. Explanatory drawing (procedure 4) of 2 sheet picking prevention operation | movement which concerns on this invention. Explanatory drawing (procedure 5) of 2 sheet picking prevention operation which concerns on this invention. Explanatory drawing (procedure 6) of 2 sheet picking_up prevention operation | movement which concerns on this invention. Explanatory drawing (procedure 7) of 2 sheet picking prevention operation | movement which concerns on this invention. Explanatory drawing (procedure 7-2) of 2 sheet picking_up prevention operation | movement which concerns on this invention. Explanatory drawing of another embodiment of a loading apparatus. FIG. 24 is an explanatory diagram of position measurement means in the loading device of FIG. Explanatory drawing of the measurement point of the mounting position of the workpiece mounted in the loading apparatus of FIG. FIG. 24 is an explanatory diagram of a measurement state of a position measurement unit in the loading device of FIG. FIG. 24 is an explanatory diagram of a measurement state of a position measurement unit in the loading device of FIG. FIG. 24 is an explanatory diagram of position calculation of a measurement point by position measurement means in the loading apparatus of FIG. The figure explaining the condition at the time of attracting and holding the workpiece in which the edge part loaded in the loading apparatus is uneven with a robot hand. A state in which workpieces with uneven edges are separated by a magnet floater. Explanatory drawing of the isolation | separation state when an air blower is used together with a magnet floater. Explanatory drawing of the example which turns over the edge part of the to-be-processed material W with a suction pad, and prevents taking 2 sheets. The example of the workpiece which has a notch part in four corners.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a bending system 1 suitable for use with a rectangular workpiece supply method to a bending machine according to the present invention.

  In the bending system 1, a loading device 5 on which a rectangular workpiece W to be folded is loaded is disposed in front of, for example, a press brake 3 that is a bending machine. A robot 7 is arranged between the device 5 and the press brake 3.

  The above-described robot 7 takes one of the uppermost layers of the workpiece loaded on the loading device 5 on behalf of a human being, and between the bending dies (not shown) attached to the press brake 3. In this bending processing system 1, an example using an articulated industrial robot is shown.

  The robot 7 is provided on a floor 9 in front of the press brake 3 so as to be movable and positionable on a base 9 extended and laid in the X-axis direction (longitudinal direction of the bending mold).

  More specifically, an X-axis carriage base 13 at the base of the robot 7 is movably engaged with a pair of X-axis guide rails 11 provided on the base 9. An X-axis motor 17 that drives a pinion (not shown) that meshes with a rack 15 provided on the base 9 is provided. By driving the X-axis motor 17, the robot 7 moves the X on the base 9. It can be moved and positioned in the axial direction.

  A main shaft 19 is provided on the X-axis carriage base 13 so as to stand in the Z-axis direction. The main shaft 19 can be rotated and positioned within a range of about 360 degrees around the Z-axis. The main shaft 19 is provided with a first arm 21 swingable in a vertical plane, and a second arm 23 is provided at the tip of the first arm 21 so as to be movable up and down in the vertical plane. A robot hand 27 provided with suction means 25 such as a plurality of vacuum suction pads, which will be described later, as end effectors is attached to the tip of the two arms 23 so as to be rotatable with respect to the axis of the second arm 23.

  As shown in FIG. 1, on the left side of the base 9, there is provided a grip changing device 29 that receives and temporarily holds a workpiece W held by the robot hand 27. Further, on the right side of the press brake 3, there is provided a product storage place 31 on which the processed product PD is placed. A robot control device 33 for controlling the robot 7 is arranged on the left side of the press brake 3.

  The loading device 5 is provided with a loading posture measuring means 36 for measuring the loading posture of a rectangular workpiece. The loading posture measuring means 36 is provided with a plate thickness measuring means 37 for holding the workpiece W held by the robot hand 27 and measuring the plate thickness with a potentiometer (see FIG. 2).

  Further, the bending system 1 is provided with a CAM computer 38 positioned above the robot control device 33. In the CAM computer 38, graphic data of bending products, bending processing related data, Data related to the robot operation and data related to the measurement point of the loading posture of the rectangular workpiece W in another loading posture measuring means 35 to be described later are created.

  The loading posture measuring means 36 has an L-shaped base 40 in which a base 40 a extending in the X-axis direction and a base 40 b extending in the Y-axis direction are integrally joined. A pair of support columns 42 are erected on the part. In addition, a guide portion 54a of a rodless cylinder 54 with a guide is provided in the X axis direction and horizontally on the support 42. A three-dimensional laser sensor 58 is held via a bracket 56 on a slider (not shown) provided in the rodless cylinder 54.

  The base 40a extended in the X-axis direction of the base 40 of the stacking posture measuring means 36 abuts and engages with the Y-axis reference side 75 of the rectangular workpiece W and the Y-axis 47 of the workpiece W. A plurality of Y-axis reference members 60 for standing in the direction are erected. Similarly, an X-axis reference member 62 is positioned on the base 40b so as to abut on and engage with the X-axis reference side 77 of the workpiece W to position in the X-axis 45 direction.

  Referring to FIGS. 3 and 4, the bracket 56 is attached with a rotary encoder 64 that detects the movement distance of the three-dimensional laser sensor 58 in the X-axis direction. The input shaft of the rotary encoder 64 is provided with a pinion 68 that meshes with a rack 66 provided in the rodless cylinder 54. Therefore, the movement position of the three-dimensional laser sensor 58 in the X-axis direction can be detected by the rotary encoder 64.

  As shown in FIGS. 5 to 8, the measurement range 70 of the three-dimensional laser sensor 58 in the stacking posture measuring means 36 is about 1000 mm in the X-axis direction, the width w in the Y-axis direction is about 400 mm, and stacks the workpieces W. The height H is about 200 mm. However, the measurement range 70 is an example and is not limited to this range.

  The measurement principle of the three-dimensional shape of the object by the three-dimensional laser sensor 58 is measured by a known light cutting method using a laser slit light 72 (for example, JP-A No. 200-193428) as shown in FIG. A contour 74 of the object OP is captured, and the measurement object OP is scanned in the X-axis direction, for example, so that a three-dimensional image is acquired as image data by a built-in camera. That is, the contour image 74 of the measurement object OP can be measured as a height value in the Y-axis direction.

  A method of measuring the stacking posture of the rectangular workpiece W by the three-dimensional laser sensor 58 will be described with reference to FIGS.

  When a plurality of rectangular workpieces W are stacked on the loading device 5 without being aligned, for example, when the uppermost workpiece W is inclined with respect to the X axis as shown in FIG. The laser slit light 72 projected from the three-dimensional laser sensor 58 onto the upper surface of the uppermost workpiece W is scanned in the X-axis direction from the origin O (0, 0) of the loading posture measuring means 36.

When the laser slit light 72 is positioned at X = C by scanning, the end of the workpiece W by the three-dimensional laser sensor 58, in this example, the Y-axis reference side 75 and the laser slit light 72 intersect with each other. _One point of coordinates (x1, y1) is detected by image analysis software built in the three-dimensional laser sensor 58. Similarly, each of the coordinates of _{P 2} points to P ₇ points (x2, y2) ~ (x7 , y7) is detected. The scan pitch can be set appropriately.

Then, based on the coordinates (x1, y1) ~ (x5 , y5) data in _{P 1} point to P ₅ points detected by the scanning described above, represents a Y-axis reference edge 75 by the least square method is a statistical method The equation of the regression line L ₁ , Y = a + bX (1) is obtained. Note that the gradient α of the regression line L ₁ is α = tan ⁻¹ b. The coefficients a and b are obtained as regression coefficients.

Similarly, coordinates (x6, y6) in ₆ points, _{P 7} point _P, based on the data of (x7, y7), the equation of the regression line _{L 2} representing the X-axis reference edge 77, Y = c + dX ·・ ・ It can be obtained as (2). Coordinates of the intersection point O 'and the straight line L ₂ from the straight line L ₁ (x, y) can be obtained by calculation (see FIG. 11). The coefficients c and d are obtained as regression coefficients.

  Referring to FIGS. 12A and 12B, the robot hand 27 includes a plurality of pneumatic cylinders 81 each having a rectangular frame member 79 attached with a vacuum pad 25 at the lower end (81a to 81f in the example of FIG. 12). The plurality of pneumatic cylinders 81 are provided so that they can be individually moved up and down by the robot control device 33.

  FIG. 13 is a diagram illustrating a state in which the pneumatic cylinder 81 of the robot hand 27 is individually waved. In the state of FIG. 13A, the workpiece W is sucked and held horizontally. 13b and 13c show a state in which the pneumatic cylinders 81a to 81f and 81g and 81h are operated so as to hit a wave. In this way, by causing the undulation operation to be performed by the pneumatic cylinder, the lower plate material of the two workpieces W taken is separated and dropped.

  Referring to FIG. 1 again, the grip changing device 29 includes a pair of horizontal holding arms 30a and 30b that hold the back side of the workpiece W by a known vacuum suction pad and horizontally hold it, and the horizontal holding arm. A pair of swivel arm means 34a that adsorbs the upper surface side of the workpiece W held horizontally by 30a and 30b by a known vacuum suction pad and swivels and holds it approximately 90 ° upward by the swing cylinders 32a and 32b. , 34b.

  A method for supplying a workpiece to the bending machine in the bending system 1 having the above configuration will be described.

  Step 1: The loading posture measuring means 36 obtains the inclination of the rectangular workpiece W with respect to the X axis 45 as a loading reference and a new coordinate origin O ′ (x, y).

  Step 2: Based on the result obtained in Step 1, the gripping posture of the robot hand is corrected to suck and hold the workpiece W, and the plurality of suction means of the robot hand 27 are individually moved up and down. The adsorbed second and subsequent workpieces are dropped onto the loading device 5.

  More specifically, from the new coordinate origin O ′ (x, y) and the inclination angle α, the robot motion reference origin is moved from O (0, 0) to the new coordinate origin O ′ (x, y) and the coordinate axis is changed. The angle is rotated by α degrees, and based on the operation reference origin O ′ (x, y) of the new robot, the gripping posture of the robot hand 27 is corrected and the workpiece is sucked and held. The suction means is individually moved up and down to separate and drop the second and subsequent workpieces.

  Step 3: The plate thickness of the workpiece held by the suction unit is measured by the plate thickness measurement unit.

  Step 4: When it is detected in Step 3 that a plurality of workpieces are held by suction, the plurality of workpieces W held by suction are conveyed to the gripping changer 29 and processed. Are temporarily held, and are picked up and held one by one from the uppermost layer of the workpiece temporarily held in the re-holding device 29 and returned to and loaded on the loading device 5.

  Step 5: Steps 1 to 3 are performed on the workpieces that have been returned and loaded.

  Step 6: When it is detected in Step 3 that a plurality of workpieces are not attracted and held, the workpieces are supplied to a bending machine.

  For example, in the step 4, for example, as shown in FIG. 14, when three sheets “A”, “B”, and “C” are sucked and held at the same time, the gripping device is changed by the following procedure 1 to procedure 7. The workpieces “A”, “B”, and “C” temporarily held in are returned and stacked on the loading device.

  “Procedure 1”: Three pieces “A”, “B”, and “C” are conveyed by the robot hand 27 of the robot 7 to the grip-replacement device 29, and the three workpieces are held horizontally. 30a and 30b are temporarily held (see FIGS. 14 and 15).

  “Procedure 2 and Procedure 3”: The uppermost layer “A” of the workpiece temporarily held in the re-holding device 29 by the robot hand 27 is sucked and held and returned and loaded onto the loading device 5 (FIG. 16, see FIG.

  “Procedure 4 and Procedure 5”: The remaining “B” and “C”, “B”, which is the upper layer, are sucked and held and returned and loaded onto the loading device 5 (see FIGS. 18 and 19).

  “Procedure 6”: Finally, the remaining “C” is sucked and held and returned and loaded onto the loading device 5 (see FIGS. 20 and 21). As a result, the loading device 5 is loaded in the reverse order of “C”, “B”, and “A” from the top.

  FIG. 22 shows a case where, in the step 1, two “A” and “B” are sucked and held and returned and loaded onto the loading device 5, and then the remaining “C” is returned and loaded (procedure 7-2). ).

  Factors that cause the work material to adhere are, for example, when there is a lot of oil on the surface of the work material, when the work material is left in a stacked state for a long time, or when the weight of the upper work material is large. It is thought that it is. Therefore, by performing the operations in steps 1 to 7 described above, air enters between the workpieces “A”, “B”, and “C”, and there is a possibility of the next adhesion without taking a heavy weight. It will be less.

  FIG. 23 is an explanatory view of another form of the loading posture measuring means 35 provided in the loading device 5.

  The loading posture measuring means 35 includes an X-axis measuring unit 39 and a Y-axis measuring unit 41 provided on a base 49.

  Since the configuration and function of the X-axis measurement unit 39 and the Y-axis measurement unit 41 are substantially the same except that the measurement direction is different, the X-axis measurement unit 39 will be described below.

  Referring to FIG. 23, the X-axis measuring unit 39 has a measuring head 43a provided with a laser displacement meter. The measuring head 43a is an X-axis 45 that is a loading reference in the Y-axis direction of the loading device 5. And can be moved and positioned in the direction of the Y axis 47, which is the loading reference in the X axis direction, and can be moved and positioned in the Z axis direction orthogonal to the X and Y axis directions.

  More specifically, as shown in FIG. 24, the X-axis measuring unit 39 has an X-axis carriage base 53 that is movably engaged with a pair of X-axis guide rails 51 provided on the base 49. The X-axis carriage base 53 is provided with a column 55 integrally provided therewith, and an X-axis servo motor 57 is provided adjacent to the column 55.

  The base 49 is provided with a rack 59 that extends in the X-axis direction and meshes with a pinion (not shown) provided on the output shaft of the servo motor 57 for driving the X-axis.

  Further, the column 55 is provided with a vertical movement cylinder 61 having a length measuring function. A Z-axis carriage base 63 is attached to the right side surface (right side in FIG. 24) of the vertical movement cylinder 61 so as to be movable up and down. is there. The Z-axis carriage base 63 holds the measuring head 43a integrally provided with the laser oscillator 65 so as to be movable in the Y-axis direction, and moves the measuring head 43a back and forth in the Y-axis direction. An attached Y-axis cylinder 67 is provided.

  The measuring head 43a is provided with a surface guide roller 69 that is rotatable in the X-axis direction in order to contact the upper surface of the workpiece W and detect the vertical position. A piston rod 71 of the Y-axis cylinder 67 is connected to the measuring head 43a.

  In the X-axis measuring unit 39 having the above-described configuration, the uppermost workpiece on which the measuring head 43a is placed on the loading device 5 by operating the servo motor 57, the vertical movement cylinder 61, and the Y-axis cylinder 67. It can be moved and positioned at an appropriate position on W. Further, the height (Z-axis coordinate) of the uppermost workpiece W can be measured by the laser displacement meter of the measuring head 43a, and the displacement of the height of the upper surface of the workpiece W is detected. The end face position of the workpiece W can be detected.

  When a plurality of rectangular workpieces W are stacked on the pallet 73 of the loading device 5 without being aligned, the inclination of the uppermost workpiece W with respect to the X axis 45 (or Y axis 47) is measured. In doing so, it is necessary to first set a measurement point P suitable for measurement on the workpiece W.

FIG. 25 is an example in which _four workpieces W _{1 to} W ₄ having a Y-axis reference side 75 and an X-axis reference side 77, which are positioning reference sides of the workpiece W, are placed in an irregular manner. workpiece W ₄ is in the top layer therein. In such a case, the measurement point P is set at a position including the straight line portions of all the Y-axis reference sides 75 and the X-axis reference sides 77 of the plurality of workpieces W _{1 to} W _4. .

More specifically, the CAM computer 38 automatically detects the straight line portion of the contour of the workpiece W from the input graphic data of the bent product, and the workpiece W loaded on the loading device 5 is detected. _Four measurement points P _{1 to} P ₄ suitable for measurement of the loading posture are designated. For example, two points P ₁ and P ₂ are designated on the Y-axis reference side 75 on the X-axis 45 side, and two points P ₃ and P ₄ are designated on the X-axis reference side 77 on the Y-axis 47 side. In the case of the rectangular workpiece W, there may be a total of three points: two points P ₁ and P _{2 on} the Y-axis reference side 75 and one point P _{3 on} the X-axis reference side 77. In FIG. 25, P ₁ is X = A, P ₂ is X = B (A <B), P ₃ is Y = C, and P ₄ is Y = D (C <D). Is.

Then, by the X-axis measuring unit 39, FIG. 26 will be described with reference to FIG. 27 for the case of measuring the inclination relative to the X-axis 45 at the top of the workpiece W _4.

When the measurement point is P ₁ (X = A), the X-axis servo motor 57 is operated to position the X coordinate of the measurement head 43a to be P ₁ , for example, A = x ₁ . Then, after raising the elevating cylinder 61 to rise limit, by stretching the Y-axis cylinder 67 to the advanced end moves above the workpiece W ₄ of the measuring head 43a loaded.

Then, by operating the elevating cylinder 61, the surface guide rollers 69 of the measuring head 43a lowers until it abuts against the workpiece W ₄ surface (the state of FIG. 26). At this time, the laser beam LB from the laser displacement meter of the measuring head 43a is projected to the surface of the workpiece W _4, the distance between the measuring head 43a and the surface position of the workpiece W ₄ is measured.

Then, the Y-axis cylinder 67 is moved to the X-axis 45 side, by detecting the displacement of the laser displacement gauge of the measuring head 43a in the Y-axis reference edge 75 of the workpiece W _4, Y-axis of the workpiece W ₄ the distance between the reference edge 75 and X-axis 45, Y = _{y 1} is measured. That is, the coordinates (x ₁ , y ₁ ) of the measurement point P ₁ are obtained. Similarly, the coordinates (x ₂ , y ₂ ) of the measurement point P ₂ are obtained (see FIG. 28).

Thus, since the coordinates _{P 1 (x} 1, _{y 1)} and _{P 2} of the coordinates _(x 2, _{y 2),} the equation of the straight line _{L 1} passing through the measurement point _{P 1} and _{P 2,} the following equation (1) Is required.
(Equation 1)
Y = {(y ₂ −y ₁ ) / (x ₂ −x ₁ )} (X−x ₁ ) + y ₁ (1)

Using the measurement head 43b of the Y-axis measurement unit 41, the coordinates (x ₃ , y ₃ ) and (x ₄ , y ₄ ) of the measurement points P ₃ and P ₄ are obtained in the same manner. Thus, the equation _{L 2} of the straight line passing through the measurement point _P 3, _{P 4} is obtained by the following equation (2).
(Equation 2)
Y = {(y ₄ −y ₃ ) / (x ₄ −x ₃ )} (X−x ₃ ) + y ₃ (2)

Further, from the formulas (1) and (2), the coordinates (x, y) of the intersection point O ′ of the straight lines L ₁ and L ₂ passing through the Y-axis reference side 75 and the X-axis reference side 77 of the workpiece W ₄ , that is, A new coordinate origin O ′ (x, y) is determined. The inclination α of the Y-axis reference side 75 with respect to the X-axis 45 is α = tan ⁻¹ (y ₂ −y ₁ ) / (x ₂ −x ₁ ). Further, the inclination β with respect to the X-axis reference side 77 Y-axis 47 is β = tan ⁻¹ (y ₄ −y ₃ ) / (x ₄ −x ₃ ).

As a result, the robot operation reference origin is moved from O (0,0) to the new coordinate origin O ′ (x, y) from the new coordinate origin O ′ (x, y) and the inclination angle α, and the coordinate axis is angle α. The workpiece W ₄ can be sucked and held by correcting the gripping posture of the robot hand 27 based on the operation reference origin O ′ (x, y) of the new robot.

1 Bending system 3 Press brake 5 Loading device 7 Robot 9 Base 11 X-axis guide rail
13 X-axis carriage base 15 Rack 17 X-axis motor 19 Main shaft 21 First arm 23 Second arm 25 Suction means 27 Robot hand 29 Re-holding device 30 (a, b) Horizontal holding arm 31 Product place 32 (a, b) Swing Dynamic cylinder
33 Robot control device 34 (a, b) Rotating arm means 35, 36 Loading posture measuring means 37 Plate thickness measuring means 38 Computer for CAM 39 X-axis measuring unit 40 Base 41 Y-axis measuring unit 42 Prop 43 Measuring head 45 X-axis 47 Y-axis 49 Measurement unit base 51 X-axis guide rail 53 X-axis carriage base 54 Rodless cylinder 54a Guide part 55 Column 56 Bracket 57 X-axis servo motor 58 Three-dimensional laser sensor 59 Rack 60 Y-axis reference member 61 Vertical movement cylinder 62 X-axis reference member 63 Z-axis carriage base 64 Rotary encoder 66 Rack 65 Laser oscillator 67 Y-axis cylinder 68 Pinion 69 Surface guide roller 71 Piston rod 72 Laser slit light 74 Contour 73 Palette 75 Y-axis reference Side 77 X-axis reference side 79 Frame member 81 Pneumatic cylinder P Measurement point OP Measurement object W Work material

Claims (3)

Workpiece material folding provided with a robot equipped with a robot hand equipped with a plurality of suction means, a CAM computer, a loading device provided with a loading posture measuring means and a plate thickness measuring means, and a work material gripping device. In a bending system, a method of supplying a rectangular work material loaded in an unaligned manner to a bending machine characterized by the following process.
1. Measuring points suitable for measuring the loading posture of the workpiece loaded on the loading device by automatically detecting the straight line of the workpiece contour from the graphic data of the bent product input to the CAM computer As described above, measurement points are set at positions including straight portions of all the Y-axis reference sides and the X-axis reference sides of the plurality of workpieces .
2 . From the measurement data obtained by the loading posture measuring means, a straight line expression representing the Y axis reference side of the uppermost workpiece loaded on the loading device and a straight line expression representing the X axis reference side are obtained, and the Y axis The inclination α of the reference side with respect to the X axis and a new origin coordinate O ′ (x, y) are calculated and obtained.
3 . Based on the inclination α with respect to the X-axis of the Y-axis reference side obtained in step 1 and the new origin coordinates O ′ (x, y), the gripping posture of the robot hand is corrected and the workpiece is sucked and held, The plurality of suction means of the robot hand are individually moved up and down to drop the second and subsequent workpieces to the loading device.
4 . The plate thickness of the workpiece held by the suction unit is measured by the plate thickness measuring unit.
5 . When it is detected in step 4 that a plurality of workpieces are sucked and held, the plurality of workpieces held by suction are conveyed to the gripping device to temporarily hold the workpiece. Then, the uppermost layer of the workpiece temporarily held in the gripping device is sucked and held one by one from the uppermost layer and returned and loaded onto the loading device.
6 . Steps 1 to 4 are performed on the workpieces returned and loaded.
7 . When it is detected in step 4 that a plurality of workpieces are not held by suction, the workpieces are supplied to a bending machine.   2. The method of feeding a rectangular workpiece stacked in an unaligned manner according to claim 1 to a bending machine, wherein the stacking posture measuring means is a method of cutting the workpiece by an optical cutting method using laser slit light. Capturing the contour and scanning the workpiece with the laser slit light to detect the position of the end surface of the workpiece in the X-axis direction and the Y-axis direction. Supplying method to the material bending machine.   2. The method of feeding a rectangular workpiece stacked in an unaligned manner according to claim 1 to a bending machine, wherein the stacking posture measuring means includes a pair of measuring heads equipped with a laser displacement meter as X, Y and It is provided so that it can be moved and positioned in the three Z directions, and the position of the end face of the workpiece in the X-axis and Y-axis directions is detected by detecting the displacement of the height of the workpiece upper surface by the laser displacement meter. A method for supplying unfolded workpieces to a bending machine, characterized in that: