An automatic die change fixture dimension detection method, device and automatic arc welding system

Abstract

The application provides an automatic die changing clamp size detection method, device and automatic arc welding system, obtains a predetermined detection order of three detection targets of length, width and height of a clamp and corresponding predetermined movement rules; according to the predetermined detection order, controls a gripper to move according to the predetermined movement rules corresponding to the current detection target, and judges whether the current detection target is qualified based on signals collected by a first detector and a second detector; if not qualified, the detection is stopped, and the gripper is controlled to place the clamp at a first predetermined position; if qualified, it is judged whether the three detection targets of length, width and height of the clamp have all been detected, if not, the detection is continued, if all, the detection is ended and the gripper is controlled to place the clamp at a second predetermined position. The structure is very simple, the cost is low, the degree of automation is high, the clamp can be accurately detected, the artificial workload is reduced, and the production efficiency of the automatic die changing system is improved.

Description

Technical Field

[0001] This invention relates to the field of robotic automatic arc welding technology, and in particular to an automatic mold changing fixture size detection method, equipment, and automatic arc welding system. Background Technology

[0002] In the automotive parts manufacturing industry, traditional arc welding operations utilize isolated arc welding workstations, where each station operates as a separate welding unit. Whenever a workpiece is changed, the corresponding workpiece fixture must be manually replaced. This results in low automation of the overall arc welding fixture changeover process. Fixture quality is also ensured through manual verification and validation after the changeover, leading to a heavy workload for both personnel and fixture inspection. This requires skilled workers, is highly dependent on manual labor, and suffers from insufficient accuracy in manual fixture inspection, increasing the possibility of human error. Currently, there is no commercially available fixture dimensional inspection equipment specifically designed for automated fixture changeover systems, necessitating custom development. Summary of the Invention

[0003] Based on the above problems, the present invention provides an automatic mold changing fixture size detection method, equipment and automatic arc welding system, which solves the technical problems of low efficiency and easy error in the fixture changing process in the prior art.

[0004] An automatic mold-changing fixture dimensional detection method includes a fixedly connected longitudinal support and a transverse support. A first detector is located at the end of the transverse support; a second detector is located at the top of the longitudinal support. The first detector emits a longitudinal linear laser and collects the signal of the longitudinal linear laser reflected due to obstruction. The second detector emits a horizontal linear laser along the transverse support and collects the signal of the horizontal linear laser reflected due to obstruction. A robot gripper grasps the fixture, and the dimensional detection process includes: Step A1: Obtain the predetermined detection sequence, corresponding predetermined movement rules, and detection judgment rules for the fixture in terms of length, width, and height. Step A2: Following the predetermined detection sequence, control the gripper to move according to the predetermined movement rules corresponding to the current detection target, and use the corresponding detection judgment rules to determine whether the current detection target is qualified based on the signals collected by the first and second detectors. If so, proceed to step A3; If not, proceed to step A4; Step A3: Determine whether the length, width, and height of the fixture have all been inspected. If so, proceed to step A5; If not, continue to step A1; Step A4: Stop the detection and control the gripper to place the fixture in the first predetermined position; Step A5: End the inspection and control the gripper to place the fixture in the second predetermined position.

[0005] Furthermore, in step A2, when the current detection target is the width of the fixture, the detection process includes: Step B21: Control the gripper to move to the first reference position so that the origin of the gripper is aligned with the first detector. At the same time, the horizontal center line of the gripper is perpendicular to the X-axis direction and parallel to the Y-axis direction in the coordinate system, and the origin of the gripper is on the horizontal center line. Step B22: Control the gripper to move to the right along the X-axis direction to deviate to the right of the first reference position by a predetermined width, and reach the first point; Step B23: Starting from the first point, control the gripper to move along the Y-axis and determine whether the first detector has acquired a valid longitudinal signal during the movement. If so, the width of the fixture is not up to standard, and proceed to step A4; If not, proceed to step B24; Step B24: Control the gripper to move leftward along the X-axis direction to deviate to the left of the first reference position by a predetermined width, and reach the second point; Step B25: Starting from the second point, control the gripper to move along the Y-axis, and during the movement, determine whether the first detector has acquired a valid longitudinal signal: If so, proceed to step A4; If not, proceed to step A3; Among them, the signal of longitudinal line laser light collected by the first detector that is obstructed and reflected within the target range is taken as the effective longitudinal signal.

[0006] Furthermore, in step A2, when the current detection target is the length of the fixture, the detection process includes: Step C21: Control the gripper to move to the second reference position so that the origin of the gripper is aligned with the first detector. At the same time, the horizontal center line of the gripper is perpendicular to the X-axis direction and parallel to the Y-axis direction in the coordinate system, and the origin of the gripper is on the horizontal center line. Step C22: Control the gripper to move backward along the length direction until it moves to the point where the first detector starts to collect a valid longitudinal signal, and then continues to move to the third point where the first detector can no longer collect a valid longitudinal signal. Calculate the depth distance of the fixture at the X-axis coordinate point at this time. Step C23: Determine whether the depth distance obtained in step C22 is less than the limit length. If not, the length of the fixture is not up to standard, proceed to step A4; If so, proceed to step C24; Step C24: Starting from the third point in step C22, control the gripper to move a predetermined width to the left and right along the X-axis, respectively, by a distance equal to the third point. During this movement, the following actions are performed: Step C241: Pause the movement along the X-axis when the first detector acquires a valid longitudinal signal; Step C242: Control the gripper to move along the Y-axis, calculate and save the depth distance of the fixture at the X-axis coordinate point based on the longitudinal effective signal collected by the first detector during the movement. Step C243: Determine whether the depth distance in step C242 is less than the limit length. If not, the length of the fixture is not up to standard, proceed to step A4; If so, proceed to step C244; Step C244: Determine whether the gripper has moved a predetermined width from the third point in both the left and right directions along the X-axis. If so, proceed to step C245; If not, control the gripper to continue moving along the X-axis and continue executing step C241; Step C245: Use the maximum value among the saved depth distances as the actual length of the fixture; Among them, the signal of longitudinal line laser light collected by the first detector that is obstructed and reflected within the target range is taken as the effective longitudinal signal.

[0007] Furthermore, in step A1, the predetermined detection sequence is to first detect the length of the fixture and then detect the height of the fixture; In step A2, when the current detection target is the height of the fixture, the detection process includes: Step D21: Control the gripper to move to the third reference position, so that the origin of the gripper is aligned with the first detector. At the same time, the horizontal center line of the gripper is perpendicular to the X-axis direction in the coordinate system and parallel to the Y-axis direction. The origin of the gripper is on the horizontal center line, and the reference horizontal plane and the second detector are on the same horizontal plane. Step D22: Control the gripper to move downward along the Z-axis by a maximum height; Step D23: Control the gripper to move backward a predetermined length along the Y-axis, and during the movement, determine whether the second detector has acquired a valid horizontal signal. If so, the height of the fixture is not up to standard, proceed to step A4; If not, proceed to step A3; Among them, the signal of the horizontal laser line collected by the second detector being reflected due to obstruction within the target range is taken as the effective horizontal signal.

[0008] Furthermore, the ultimate height Z is calculated using the following formula: ; in, Y is the calculated actual length of the fixture; Z represents the maximum height; Both a and b are constant values.

[0009] Furthermore, in step B23, the gripper is controlled to move backward along the Y-axis and during the movement, it is determined whether the first detector has acquired a valid longitudinal signal; In step B25, the gripper is controlled to move forward along the Y-axis, and during the movement, it is determined whether the first detector has acquired a valid longitudinal signal. The backward direction in the Y-axis direction is the direction from the origin of the gripper toward the rear end of the gripper; The forward direction in the Y-axis direction refers to the direction from the origin of the gripper towards the gripper's clamping area, which is opposite to the backward direction in the Y-axis direction.

[0010] Furthermore, in steps C22 and C242, the depth distance of the fixture refers to the straight-line distance between the front and rear boundary points of the fixture when corresponding to the same X-axis coordinate point.

[0011] Furthermore, in step C21, after reaching the second reference position, the method further includes determining the reference longitudinal plane, which refers to the longitudinal plane on which the boundary point on the fixture is closest to the inner end face of the gripper. In steps C22 and C242, the depth distance of the fixture refers to the distance between the front edge boundary point of the fixture and the reference longitudinal surface.

[0012] An automatic mold-changing fixture dimensional inspection device, used to implement the aforementioned automatic mold-changing fixture dimensional inspection method, includes: A fixed horizontal support and a vertical support are provided, with a first detector installed at the end of the horizontal support and a second detector installed at the top of the vertical support. The first detector is used to emit a longitudinal line laser and collect the signal of the longitudinal line laser reflected due to obstruction; the second detector is used to emit a horizontal line laser along the transverse support direction and collect the signal of the horizontal line laser reflected due to obstruction. The robotic gripper used to grasp the fixture and the first control module on the robot; The first control module is used to control the gripper to move according to the predetermined movement rules corresponding to the current detection target, in accordance with the predetermined detection sequence of the three detection targets of the fixture: length, width and height. The second control module is connected to the first detector and the second detector respectively. It is used to determine whether the current detection target is qualified based on the signals collected by the first detector and the second detector according to the corresponding detection judgment rules, and to obtain the detection result. The first control module connects to the second control module and is used for: When the test result shows that the current test target is unqualified, the test is stopped and the gripper is controlled to place the fixture in the first predetermined position; If the test result shows that the current target is qualified and there are still targets to be tested, continue testing; When the test result shows that the current test target is qualified and all test targets have been tested, the test ends and the gripper is controlled to place the fixture into the second predetermined position.

[0013] An automatic arc welding system uses an automatic mold changing fixture size detection device as described above, and also includes a fixture inbound / outbound slide, a fixture vertical storage, an automatic fixture frame, an H-type positioner, and an automatic arc welding station; The clamp loading and unloading slide is used for loading clamps; The dimension inspection equipment is set in the area near the fixture entry and exit slide table. It is used to inspect the dimensions of the fixture. When the inspection is qualified, the fixture is sent to the second predetermined position. When the inspection is unqualified, the control gripper is used to place the fixture in the first predetermined position. The second predetermined position is the fixture vertical storage. The robot in the dimensional inspection equipment is also used to control the gripper to pick up the fixture from the fixture storage unit and replace it with the automatic fixture frame; Automatic arc welding stations are used for arc welding operations on workpieces in fixtures; H-type positioners are used to rotate fixtures so that automatic arc welding stations can perform arc welding operations on workpieces.

[0014] The beneficial technical effects of this invention are as follows: This invention uses a robot-driven gripper to grasp and move the fixture, in conjunction with an automatic mold changing system for arc welding fixtures. It can automatically detect the length, width, and height of the fixture using only two low-cost detectors. Moreover, the gripper can share the robot and gripper used to clamp the fixture into the fixture frame. The automatic mold changing fixture size detection equipment has a very simple structure, low cost, and high degree of automation. It can achieve accurate fixture detection, full automation, and no human intervention is required, which greatly reduces the workload of manual labor and improves the production efficiency of the automatic mold changing system. Attached Figure Description

[0015] Figure 1-2 This is a schematic diagram of an automatic mold-changing fixture frame in the prior art; Figure 3 A schematic diagram showing the maximum height required for an automatic mold changing fixture; Figure 4 This is a three-dimensional structural diagram of an automatic mold changing fixture size detection device according to the present invention; Figure 5 This is a schematic diagram of the structure of an automatic arc welding system according to the present invention; Figure 6This is a schematic diagram of a module of an automatic mold changing fixture size detection device according to the present invention; Figure 7 This is a schematic diagram of the laser emission direction of the detector in an automatic mold changing fixture size detection device according to the present invention; Figure 8-11 This is a schematic diagram of the fixture width detection process in the automatic mold changing fixture size detection method of the present invention; Figure 12-13 This is a schematic diagram of the fixture length detection process in the automatic mold changing fixture size detection method of the present invention; Figure 14-15 This is a schematic diagram of the fixture height detection process in the automatic mold changing fixture size detection method of the present invention; Figure 16-19 This is a flowchart illustrating the steps of an automatic mold-changing fixture size detection method according to the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0019] See Figure 4 and Figure 16 This invention provides an automatic mold-changing fixture size detection method, comprising a fixedly connected longitudinal support and a transverse support. A first detector is located at the end of the transverse support; a second detector is located at the top of the longitudinal support. The first detector emits a longitudinal linear laser and collects the signal of the longitudinal linear laser reflected due to obstruction. The second detector emits a horizontal linear laser along the transverse support and collects the signal of the horizontal linear laser reflected due to obstruction. A robot gripper grasps the fixture, and the size detection process includes: Step A1: Obtain the predetermined detection sequence, corresponding predetermined movement rules, and detection judgment rules for the fixture in terms of length, width, and height. Step A2: Following the predetermined detection sequence, control the gripper to move according to the predetermined movement rules corresponding to the current detection target, and use the corresponding detection judgment rules to determine whether the current detection target is qualified based on the signals collected by the first and second detectors. If so, proceed to step A3; If not, proceed to step A4; Step A3: Determine that the length, width, and height of the fixture have all been inspected. If so, proceed to step A5; If not, continue to step A1; Step A4: Stop the detection and control the gripper to place the fixture in the first predetermined position; Step A5: End the inspection and control the gripper to place the fixture in the second predetermined position.

[0020] In step A1, the predetermined detection sequence may be, for example, detecting the clamp width first, then the clamp length, and finally the clamp height.

[0021] For example, both the first and second detectors are line laser detectors. The line laser detector emits a laser beam, which is reflected by objects within the target area. Collecting this reflected signal constitutes a valid signal. If no reflected signal is collected, or if the collected reflected signal indicates a significant distance, it can be considered that the detector has not collected a valid signal. Whether a signal is valid is determined by a logical algorithm analyzing whether the reflected signal is a valid signal reflected by the gripper or hand. If it is a valid signal, the detector is considered to have collected a valid signal because during detection, the gripper moves to the target area near the first and second detectors, blocking the line laser beam. The distance from the reflected signal to the detector is relatively short, so the reflected signal can be considered a valid signal. If the gripper is not present, or although it moves to the target area but does not block the line laser beam, either there is no reflected signal, or the distance from the reflected signal to the detector is long, so it is considered an invalid signal. The first detector emits a laser beam vertically, and the reflected laser beam encountered by the gripper or hand is collected by the first detector. The second detector emits a laser beam horizontally, and the reflected laser beam encountered by the gripper or hand is collected by the second detector.

[0022] Preferred, such as Figure 7 As shown, the laser emitted by the first detector and the laser emitted by the second detector are coplanar.

[0023] Furthermore, the fixture is an automatic mold-changing fixture.

[0024] A heavy-duty robot forks and moves the automatic mold-changing fixture to the inspection position on the fixture inspection bracket for testing. The robot's motion accuracy and the laser detection sensor's accuracy are both high, avoiding the inaccuracies and false detections associated with manual inspection. The heavy-duty robot is also an existing component of the automatic mold-changing system for arc welding fixtures; only the addition of the fixture inspection bracket and two detectors is needed to achieve automatic dimensional inspection of the fixtures within the automatic mold-changing system. This automatic mold-changing fixture dimensional inspection equipment is highly automated, easy to use, and its implementation method is simple, stable, and reliable.

[0025] like Figure 1 As shown, the automatic mold-changing fixture is mainly used in the automatic fixture frame of the H-type positioner in an automatic arc welding station. When arranging the fixture frame, two sets of automatic fixtures are typically installed simultaneously and can be interchanged arbitrarily in the left and right positions. A 10mm gap is reserved between the fixtures. The zero points of the automatic fixtures are symmetrically distributed left and right. For example, the maximum width of the fixture can be 1000mm. It should be noted that the maximum width of different fixtures may vary depending on the fixture frame.

[0026] like Figure 2 As shown, X, Y, and Z, set on the fixture frame, represent the limit dimensions of the fixture in the width, length, and height directions, respectively. The fixture must not exceed the limit width, limit length, and limit height. Figure 1 Taking the clamp frame as an example, the maximum width is 1005mm and the maximum length is 1300mm. The maximum dimensions of different clamps may vary due to the different clamp frames. In describing the technical solution of this invention, the maximum width of 1005mm and the maximum length of 1300mm are used as examples.

[0027] like Figure 3 As shown, the automatic fixture is fixed on the automatic fixture frame. Both the automatic fixture frame and the fixture can rotate on the small shaft of the positioner, facilitating robotic welding. From the image, it can be determined that all components on the fixture must not exceed the rotation area of ​​the circle; otherwise, rotation will interfere. Following this arrangement, for example, if the maximum length of the fixture is 1300mm, since the mounting reference surface at the bottom of the fixture is not on the rotation center line, but is at a distance of, for example, 92mm, from the rotation center line, the maximum height is 1300mm / 2 + 92mm.

[0028] Therefore, if the dimensions of the fixture in all directions are found to exceed the corresponding limit dimensions, it is considered qualified.

[0029] See Figure 17 , Figure 8-11 Furthermore, in step A2, when the current detection target is the width of the fixture, the detection process includes: Step B21: Control the gripper to move to the first reference position so that the origin of the gripper is aligned with the first detector. At the same time, the horizontal center line of the gripper is perpendicular to the X-axis direction and parallel to the Y-axis direction in the coordinate system, and the origin of the gripper is on the horizontal center line. Step B22: Control the gripper to move to the right along the X-axis direction to deviate to the right of the first reference position by a predetermined width, and reach the first point; Step B23: Starting from the first point, control the gripper to move along the Y-axis and determine whether the first detector has acquired a valid longitudinal signal during the movement. If so, the width of the fixture is not up to standard, and proceed to step A4; If not, proceed to step B24; Step B24: Control the gripper to move leftward along the X-axis direction to deviate to the left of the first reference position by a predetermined width, and reach the second point; Step B25: Starting from the second point, control the gripper to move along the Y-axis, and during the movement, determine whether the first detector has acquired a valid longitudinal signal: If so, proceed to step A4; If not, proceed to step A3; Among them, the signal of longitudinal line laser light collected by the first detector that is obstructed and reflected within the target range is taken as the effective longitudinal signal.

[0030] Furthermore, the predetermined width is half of the maximum width of the fixture allowed by the automatic fixture frame.

[0031] During the width inspection process, because the first detector is a line laser detector that emits line laser light, the gripper must first be positioned. Since the gripper width varies, the opening degree of the two fingers will differ, but the two fingers are generally symmetrical, and the horizontal centerline remains constant. The gripper's horizontal centerline is used for alignment. The gripper's origin is on its inner end face. The gripper moves until its inner end face is aligned with the first detector; alignment means that it is almost coplanar with the line laser emitted by the first detector. With the gripper origin aligned with the first detector, the centerline must naturally intersect the line laser emitted by the first detector at the gripper's origin. Furthermore, with the horizontal centerline aligned, the direction perpendicular to the horizontal centerline is the width direction of the gripper, i.e., the X-axis direction. In this way, after moving the gripper of the clamp to the left and right by half its maximum width along the X-axis, the gripper is then moved along the Y-axis (perpendicular to the X-axis). If the clamp is within its maximum width, half its width must be less than the predetermined width. Therefore, when moving along the Y-axis, the linear laser emitted by the first detector is not blocked by the clamp and gripper, and no valid signal can be detected, indicating that the width dimension is acceptable. If the clamp deviates to the left and right by a predetermined width, and the first detector detects a valid signal when moving along the Y-axis, it indicates that the clamp width exceeds the maximum width, and the clamp is unacceptable.

[0032] See Figure 12-13 , Figure 18 Furthermore, in step A2, when the current detection target is the length of the fixture, the detection process includes: Step C21: Control the gripper to move to the second reference position so that the origin of the gripper is aligned with the first detector. At the same time, the horizontal center line of the gripper is perpendicular to the X-axis direction and parallel to the Y-axis direction in the coordinate system, and the origin of the gripper is on the horizontal center line. Step C22: Control the gripper to move backward along the length direction until it moves to the point where the first detector starts to collect a valid longitudinal signal, and then continues to move to the third point where the first detector can no longer collect a valid longitudinal signal. Calculate the depth distance of the fixture at the X-axis coordinate point at this time. Step C23: Determine whether the depth distance obtained in step C22 is less than the limit length. If not, the length of the fixture is not up to standard, proceed to step A4; If so, proceed to step C24; Step C24: Starting from the third point in step C22, control the gripper to move a predetermined width to the left and right along the X-axis, respectively, by a distance equal to the third point. During this movement, the following actions are performed: Step C241: Pause the movement along the X-axis when the first detector acquires a valid longitudinal signal; Step C242: Control the gripper to move along the Y-axis, calculate and save the depth distance of the fixture at the X-axis coordinate point based on the longitudinal effective signal collected by the first detector during the movement. Step C243: Determine whether the depth distance in step C242 is less than the limit length. If not, the length of the fixture is not up to standard, proceed to step A4; If so, proceed to step C244; Step C244: Determine whether the gripper has moved a predetermined width from the third point in both the left and right directions along the X-axis. If so, proceed to step C245; If not, control the gripper to continue moving along the X-axis and continue executing step C241; Step C245: Use the maximum value among the saved depth distances as the actual length of the fixture; Among them, the signal of longitudinal line laser light collected by the first detector that is obstructed and reflected within the target range is taken as the effective longitudinal signal.

[0033] During the verification of the fixture length, the gripper is first moved to a reference position to facilitate subsequent operations. The first and second reference positions can be the same, and their common feature is that the origin of the gripper is aligned with the linear laser emitted by the first detector, and the horizontal center line is perpendicular to the Z-axis. This allows us to first move along the Y-axis to calculate the depth distance at the center of the fixture's width based on the signals collected and uncollected by the first detector. Then, we move the gripper left and right along the X-axis by a predetermined width, combined with movement along the Y-axis, to detect which Z-axis coordinate points have a depth distance greater than the center of the width, thus finding the maximum depth distance as the actual length of the fixture.

[0034] See Figure 14-15 , Figure 19 , furthermore, in step A1, the predetermined detection sequence is to detect the length of the fixture first and then the height of the fixture; In step A2, when the current detection target is the height of the fixture, the detection process includes: Step D21, control the gripper to move to the third reference position, so that the gripper origin is aligned with the first detector. At the same time, the horizontal center line of the gripper is perpendicular to the X-axis direction in the coordinate system and parallel to the Y-axis direction. The gripper origin is on the horizontal center line, and make the reference horizontal plane and the second detector coplanar; Step D22, control the gripper to move downward by a limit height along the Z-axis direction; Step D23, control the gripper to move backward by a predetermined length along the Y-axis direction, and judge whether the second detector collects a detection valid signal during the movement: If so, the height of the fixture is unqualified, and step A4 is executed; If not, step A3 is executed; Among them, the signal reflected by the horizontal line laser blocked in the target range collected by the second detector is used as the horizontal valid signal.

[0035] Furthermore, the limit height Z is calculated according to the following formula: ; Among them, Y is the actual length of the fixture calculated; Z is the limit height; Both a and b are constant values. Specifically, b is half of the limit length. Specifically, a is the distance from the bottom mounting base surface of the fixture to the rotation center line, According to the foregoing analysis of Figure 3 , the fixture can be qualified only when it is less than or does not exceed the above limit height Z. Therefore, the limit width of the fixture is determined according to the calculated actual length of the fixture.

[0036] During height detection, the reference horizontal plane and the laser line emitted by the second detector need to be aligned. Under normal circumstances, the horizontal plane where the lower edge of the gripper's fingers lies is considered the reference horizontal plane. That is, when the gripper moves from top to bottom along the Z-axis (vertical direction), and the second detector goes from not acquiring a valid signal to acquiring one, the horizontal plane where the laser line emitted by the second detector at the point of acquiring a valid signal is located is considered the reference horizontal plane. This reference horizontal plane can generally be the mounting surface of the fixture or the lower edge of the gripper's fingers. However, the lower edge of the gripper's fingers and the mounting surface of the fixture are generally not far apart, so an approximation can be made, i.e., the detected valid signal is considered the reference horizontal plane. This scanning mainly focuses on the middle area of ​​the fixture, rather than the edge areas, which are easier to scan. After the reference horizontal plane and the line laser emitted by the second detector, the gripper is moved downward by a limit height Z. Then, the line laser emitted by the second detector is parallel to the X-axis and perpendicular to the Y-axis. Therefore, the gripper is controlled to move backward along the Y-axis by a predetermined length, so that the second detector scans horizontally above the gripper's gripping area at a height Z above the reference horizontal plane. If the second detector detects a valid signal, the gripper height is considered to exceed the limit height and is therefore unqualified. If no valid signal is detected, the gripper height is considered to be qualified.

[0037] In another embodiment of the present invention, the laser direction emitted by the second detector can be parallel to the Y-axis direction. In this way, after the gripper and the first detector are aligned, the gripper moves along the X-axis direction toward the position projected on the X-axis direction of the second detector, so that the second detector scans horizontally above the gripper's gripping area at a height Z above the reference horizontal plane. If the second detector detects a valid signal, it is considered that the clamp height exceeds the limit height and is unqualified. If no valid signal is collected, the clamp height is considered to be qualified.

[0038] Furthermore, such as Figure 9 As shown, in step B23, the gripper is controlled to move backward along the Y-axis and during the movement, it is determined whether the first detector has acquired a valid longitudinal signal; In step B25, as Figure 11 As shown, the gripper is controlled to move forward along the Y-axis and during the movement, it is determined whether the first detector has acquired a valid longitudinal signal: The backward direction in the Y-axis direction is the direction from the origin of the gripper toward the rear end of the gripper; The forward direction in the Y-axis direction refers to the direction from the origin of the gripper towards the gripper's clamping area, which is opposite to the backward direction in the Y-axis direction.

[0039] In this way, the first detector can pass through a section of the entire gripping area projected along the Y-axis. In this method, in step B24, the gripper is directly controlled to move two predetermined widths to the left along the X-axis to reach a point as the second point. Therefore, in step B25, the gripper is controlled to move forward along the Y-axis to achieve width qualification detection.

[0040] In another embodiment of the present invention, in step B24, the gripper can be controlled to move forward along the Y-axis by a predetermined length to return to the first point, and then move to the left by two predetermined widths along the X-axis to reach the second point. Then, in step B25, the gripper is controlled to move backward along the Y-axis by a predetermined length to detect whether the width is qualified.

[0041] Furthermore, in steps C22 and C242, the depth distance of the fixture refers to the straight-line distance between the front and rear boundary points of the fixture when corresponding to the same X-axis coordinate point.

[0042] Generally, the side of the gripper closest to the inner end face of the gripper is flat, without any additional area protruding into the inner end face of the gripper. Therefore, the depth of the gripper can be directly determined by the maximum depth distance between the front and rear boundaries, which determines the actual length of the gripper.

[0043] During the process of controlling the gripper to move left and right along the X-axis from the third point, moving a predetermined length to the right, if the first detector detects a valid signal, it indicates that the actual depth distance of the fixture may be greater than the depth distance at the horizontal center line of the gripper. At this point, the movement to the right along the X-axis is paused, and the gripper is controlled to move forward along the Y-axis until it reaches the rear boundary of the fixture (i.e., the last valid signal collected by the first detector at the rear). Then, it moves forward along the Y-axis until it reaches the front boundary of the fixture (i.e., the last valid signal collected by the first detector at the front). The distance between the two boundaries is the depth distance. If the depth distance exceeds the limit length, the fixture is considered unqualified. If the depth distance does not exceed the limit, the movement along the X-axis continues until a predetermined width of movement to the right is completed. During movement, the gripper can be controlled to return to the pause point and continue moving to the right along the X-axis, or it can directly move to the right along the X-axis from the current front boundary of the fixture. If the first detector does not detect a valid signal, it indicates that this boundary point is the maximum on this half. If the first detector detects a valid signal, it indicates that there is a greater depth distance in the fixture.

[0044] Then, move the device to the left by a predetermined width, and continue moving it to the left by another predetermined width. Continue detecting the depth distance of the other half of the previously detected fixture until the entire depth distance has been detected. The maximum depth distance is then taken as the actual length of the fixture.

[0045] Furthermore, in step C21, after reaching the second reference position, the method further includes determining the reference longitudinal plane, which refers to the longitudinal plane on which the boundary point on the fixture is closest to the inner end face of the gripper. In steps C22 and C242, the depth distance of the fixture refers to the distance between the front edge boundary point of the fixture and the reference longitudinal surface.

[0046] In extreme cases, the rear end of the gripper facing the inner end face of the gripper may not be a straight plane and may have protrusions. If the front end of the gripper also has protrusions, the front and rear protrusions may not correspond but be staggered. In fact, the Y-axis distance between the front and rear protrusions is the actual length of the gripper. Therefore, as another embodiment of the present invention, starting from the second reference position, the gripper is first moved backward along the Y-axis direction to the point where the first detector detects a valid signal, which is considered the boundary point of the gripper. The gripper is then moved forward along the Y-axis direction to the point where the first detector does not detect a valid signal, and then moved left and right by a predetermined width from that point. If the first detector collects a valid signal during the movement, the movement is paused, and the gripper is moved forward along the Y-axis direction to the rear end boundary of the gripper again. The longitudinal plane containing the point where the rear end boundary of the gripper is closest to the inner end face of the gripper is taken as the reference longitudinal plane.

[0047] Subsequently, as before, the device moves backward along the Y-axis from the second reference position so that the first detector detects the front edge of the fixture. Then, based on the third point, it moves left and right along the X-axis to find the maximum depth distance from the front edge of the fixture to the reference longitudinal plane, which is taken as the actual length of the fixture.

[0048] It is worth noting that, in a preferred embodiment of the present invention, during the clamp width detection, after reaching the first reference position in step B21 and before executing step B22, step B20 is also executed, controlling the gripper to move backward along the Y-axis until the first detector first acquires a valid longitudinal signal, and this point is designated as the fourth point. Alternatively, after the gripper first acquires a valid longitudinal signal, the point where the gripper moves forward along the Y-axis to the point where the first detector begins to fail to acquire a valid longitudinal signal is designated as the fourth point. Then, using the fourth point as the starting point, step B22 continues. In this case, the predetermined length of movement in steps B23 and B25 can be the limit length.

[0049] See Figure 4 and Figure 6 The present invention also provides an automatic mold-changing fixture size detection device for implementing the aforementioned automatic mold-changing fixture size detection method, comprising: A horizontal support (21) and a vertical support (22) are fixedly connected. A first detector (23) is installed at the end of the horizontal support (21), and a second detector (24) is installed at the top of the vertical support (22). The first detector (23) is used to emit longitudinal line laser and collect the signal of longitudinal line laser reflected due to obstruction; the second detector (24) is used to emit horizontal line laser along the transverse support direction and collect the signal of horizontal line laser reflected due to obstruction; the robot gripper (11) is used to grasp the clamp (7) and the first control module (12) on the robot. The first control module (12) is used to control the gripper (11) to move according to the predetermined movement rules corresponding to the current detection target, according to the predetermined detection sequence of the three detection targets of the clamp (7) in terms of length, width and height. The second control module (13) is connected to the first detector (23) and the second detector (24) respectively. It is used to determine whether the current detection target is qualified based on the signals collected by the first detector (23) and the second detector (24) according to the corresponding detection judgment rules, and obtain the detection result. The first control module (12) is connected to the second control module (13) and is used for: When the test result indicates that the current test target is unqualified, the test is stopped, and the gripper is controlled to place the clamp (7) into the first predetermined position; If the test result shows that the current target is qualified and there are still targets to be tested, continue testing; When the test result shows that the current test target is qualified and all test targets have been tested, the test ends and the gripper is controlled to place the clamp (7) into the second predetermined position.

[0050] Furthermore, the predetermined inspection sequence could be, for example, to inspect the fixture width first, then the fixture length, and finally the fixture height.

[0051] For example, both the first and second detectors are line laser detectors. The line laser detector emits a laser beam, which is reflected back to an object, producing a valid signal. If no valid signal is reflected, the detector is considered not to have collected a valid signal. If a valid signal is collected, a logical algorithm analyzes whether the reflected signal is a valid signal from the gripper or hand. If it is a valid signal, the detector is considered to have collected a valid signal. The first detector emits a laser beam vertically, and the reflected laser beam is collected by the first detector when it encounters a gripper or hand. The second detector emits a laser beam horizontally, and the reflected laser beam is collected by the second detector when it encounters a gripper or hand.

[0052] Preferably, the laser emitted by the first detector and the laser emitted by the second detector are coplanar.

[0053] Furthermore, the fixture (7) is an automatic mold changing fixture.

[0054] A heavy-duty robot forks and moves the automatic mold-changing fixture to the inspection position on the fixture inspection bracket for testing. The robot's motion accuracy and the laser detection sensor's accuracy are both high, avoiding the inaccuracies and false detections associated with manual inspection. The heavy-duty robot is also an existing component of the automatic mold-changing system for arc welding fixtures; only the addition of the fixture inspection bracket and two detectors is needed to achieve automatic dimensional inspection of the fixtures within the automatic mold-changing system. This automatic mold-changing fixture dimensional inspection equipment is highly automated, easy to use, and its implementation method is simple, stable, and reliable.

[0055] See Figure 5 The present invention also provides an automatic arc welding system, which uses an automatic mold changing fixture size detection device as described above, and further includes a fixture in-and-out slide (2), a fixture vertical storage (3), an automatic fixture frame (4), an H-type positioner (5), and an automatic arc welding station (6). The clamp inlet / outlet slide (2) is used for loading the clamp (7); The size inspection device (1) is set in the area near the inbound and outbound slide (2) of the fixture (7) for size inspection of the fixture. When the inspection is qualified, the fixture is sent to the second predetermined position. When the inspection is unqualified, the gripper is controlled to place the fixture in the first predetermined position. The second predetermined position is the fixture vertical storage (3). The robot in the size inspection equipment (1) is also used to control the gripper to pick up the fixture from the fixture storage and replace it in the automatic fixture frame (4); The automatic arc welding station (6) is used to perform arc welding on the workpieces on the fixture; The H-type positioner (5) is used to rotate the fixture so that the automatic arc welding station can perform arc welding on the workpiece.

[0056] The automatic fixture is manually loaded onto the fixture loading / unloading slide. A robot, using a handheld gripper, moves the fixture to a fixture inspection bracket for automatic length, width, and height checks. Once the checks are passed, the automatic fixture is placed in the fixture storage unit. When the automatic fixture is needed, the robot's handheld gripper moves it from the storage unit to the automatic fixture frame of the H-type positioner in the automatic arc welding station. The fixture is automatically locked and the pneumatic and electrical circuits are connected, enabling automatic fixture replacement. The fixture, after automatic dimensional checks, fully meets the dimensional requirements of the arc welding station's fixture frame. This automatic fixture length, width, and height checks ensure that the dimensional requirements of the automatic fixture are met, avoiding interference problems during automatic mold changing. When used in conjunction with an automated production line, it greatly reduces manual inspection work, shortens fixture changeover time, and improves the production efficiency of the automatic mold-changing production line.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for automatically detecting the dimensions of a mold-changing fixture, characterized in that, A fixedly connected longitudinal support and transverse support are provided. The end of the transverse support is provided with a first detector. The top of the longitudinal support is provided with a second detector. The first detector emits a longitudinal line laser and collects the signal of the longitudinal line laser reflected due to obstruction. The second detector emits a horizontal laser beam along the transverse support direction and collects the signal of the horizontal laser beam reflected due to obstruction; the robot's gripper grasps the fixture, and the size detection process includes: Step A1: Obtain the predetermined detection sequence, predetermined movement rules, and detection judgment rules for the fixture in terms of the three detection targets of length, width, and height; Step A2: According to the predetermined detection sequence, control the gripper to move according to the predetermined movement rule corresponding to the current detection target, and use the corresponding detection judgment rule to determine whether the current detection target is qualified based on the signals collected by the first detector and the second detector. If so, proceed to step A3; If not, proceed to step A4; Step A3: Determine that the length, width, and height of the fixture have all been detected. If so, proceed to step A5; If not, continue with step A1; Step A4: Stop the detection and control the gripper to place the clamp in the first predetermined position; Step A5: End the detection and control the gripper to place the clamp in the second predetermined position; In step A2, when the current detection target is the width of the fixture, the detection process includes: Step B21: Control the gripper to move to the first reference position, so that the origin of the gripper is aligned with the first detector, and at the same time, the horizontal center line of the gripper is perpendicular to the X-axis direction and parallel to the Y-axis direction in the coordinate system, and the origin of the gripper is on the horizontal center line; Step B22: Control the gripper to move to the right along the X-axis direction to deviate to the right from the first reference position by a predetermined width, and reach the first point; Step B23: Starting from the first point, control the gripper to move along the Y-axis and determine during the movement whether the first detector has acquired a valid longitudinal signal. If so, the width of the fixture is unqualified, and step A4 is executed; If not, proceed to step B24; Step B24: Control the gripper to move leftward along the X-axis direction to deviate leftward from the first reference position by a predetermined width, and reach the second point; Step B25: Starting from the second point, control the gripper to move along the Y-axis, and during the movement, determine whether the first detector has acquired a valid longitudinal signal. If so, proceed to step A4; If not, proceed to step A3; Specifically, the signal of the longitudinal line laser collected by the first detector that is obstructed and reflected within the target range is taken as the longitudinal effective signal.

2. The automatic mold-changing fixture dimension detection method as described in claim 1, characterized in that, In step A2, when the current detection target is the length of the fixture, the detection process includes: Step C21: Control the gripper to move to the second reference position, so that the origin of the gripper is aligned with the first detector, and the horizontal center line of the gripper is perpendicular to the X-axis direction and parallel to the Y-axis direction in the coordinate system, and the origin of the gripper is on the horizontal center line; Step C22: Control the gripper to move backward along the length direction until it moves to the third point where the first detector starts to collect a valid longitudinal signal and continues to move until the first detector can no longer collect a valid longitudinal signal. Calculate the depth distance of the fixture at the X-axis coordinate point at this time. Step C23: Determine whether the depth distance obtained in step C22 is less than the limit length. If not, the length of the fixture is not up to standard, and step A4 is executed. If so, proceed to step C24; Step C24: Starting from the third point mentioned in step C22, control the gripper to move a predetermined width away from the third point in both the left and right directions along the X-axis. During this movement, the following actions are performed: Step C241: Pause the movement along the X-axis when the first detector acquires a valid longitudinal signal; Step C242: Control the gripper to move along the Y-axis direction, calculate and save the depth distance of the fixture at the X-axis coordinate point at this time based on the longitudinal effective signal result collected by the first detector during the movement: Step C243: Determine whether the depth distance in step C242 is less than the limit length. If not, the length of the fixture is not up to standard, and step A4 is executed. If so, proceed to step C244; Step C244: Determine whether the gripper has moved a predetermined width from the third point in both the left and right directions along the X-axis. If so, proceed to step C245; If not, control the gripper to continue moving along the X-axis and continue executing step C241; Step C245: The maximum value among the saved depth distances is taken as the actual length of the clamp; Specifically, the signal of the longitudinal line laser collected by the first detector that is obstructed and reflected within the target range is taken as the longitudinal effective signal.

3. The automatic mold-changing fixture dimension detection method as described in claim 1, characterized in that, In step A1, the predetermined detection sequence is to first detect the length of the fixture and then detect the height of the fixture; In step A2, when the current detection target is the height of the fixture, the detection process includes: Step D21: Control the gripper to move to the third reference position, so that the origin of the gripper is aligned with the first detector, and the horizontal center line of the gripper is perpendicular to the X-axis direction and parallel to the Y-axis direction in the coordinate system. The origin of the gripper is on the horizontal center line, and the reference horizontal plane and the second detector are on the same horizontal plane. Step D22: Control the gripper to move downward along the Z-axis direction by a maximum height; Step D23: Control the gripper to move backward a predetermined length along the Y-axis direction, and determine whether the second detector has acquired a valid horizontal signal during the movement. If so, the height of the fixture is unqualified, and step A4 is executed; If not, proceed to step A3; Specifically, the signal of the horizontal laser beam collected by the second detector that is obstructed and reflected within the target range is taken as the effective horizontal signal.

4. The automatic mold-changing fixture dimension detection method as described in claim 3, characterized in that, The extreme height Z is calculated according to the following formula: ； in, Y is the calculated actual length of the fixture; Z represents the extreme height; Both a and b are constant values.

5. The automatic mold-changing fixture dimension detection method as described in claim 1, characterized in that, In step B23, the gripper is controlled to move backward along the Y-axis and during the movement, it is determined whether the first detector has acquired a valid longitudinal signal. In step B25, the gripper is controlled to move forward along the Y-axis, and during the movement, it is determined whether the first detector has acquired a valid longitudinal signal. The rearward direction of the Y-axis is the direction from the origin of the claw towards the rear end of the claw; The forward direction of the Y-axis refers to the direction from the origin of the gripper toward the gripper's clamping area, which is opposite to the backward direction of the Y-axis.

6. The automatic mold-changing fixture dimension detection method as described in claim 2, characterized in that, In step C22 and step C242, the depth distance of the fixture refers to the straight-line distance between the front and rear boundary points of the fixture when corresponding to the same X-axis coordinate point.

7. The automatic mold-changing fixture dimension detection method as described in claim 2, characterized in that, In step C21, after reaching the second reference position, the method further includes determining a reference longitudinal plane, which refers to the longitudinal plane on which the boundary point on the fixture is closest to the inner end face of the gripper. In step C22 and step C242, the depth distance of the fixture refers to the distance between the front end boundary point of the fixture and the reference longitudinal surface.

8. An automatic mold-changing fixture size detection device, characterized in that, A method for implementing an automatic mold-changing fixture dimension detection method as described in any one of claims 1-7 includes: A horizontal support and a vertical support are fixedly connected, with a first detector installed at the end of the horizontal support and a second detector installed at the top of the vertical support. The first detector is used to emit a longitudinal line laser and collect the signal of the longitudinal line laser reflected due to obstruction; the second detector is used to emit a horizontal line laser along the transverse support direction and collect the signal of the horizontal line laser reflected due to obstruction. A robotic gripper for grasping a fixture and a first control module on the robot; The first control module is used to control the gripper to move according to the predetermined movement rule corresponding to the current detection target, according to the predetermined detection order of the three detection targets of the clamp: length, width and height. The second control module is connected to the first detector and the second detector respectively, and is used to determine whether the current detection target is qualified based on the signals collected by the first detector and the second detector according to the corresponding detection judgment rules, and to obtain the detection result; The first control module is connected to the second control module and is used for: When the detection result indicates that the current detection target is unqualified, the detection is stopped, and the gripper is controlled to place the clamp into the first predetermined position; When the detection result indicates that the current detection target is qualified and there are still other detection targets to be detected, the detection continues; When the detection result indicates that the current detection target is qualified and all detection targets have been detected, the detection ends, and the gripper is controlled to place the clamp into the second predetermined position.

9. An automatic arc welding system, characterized in that, The automatic mold changing fixture size detection equipment as described in claim 8 further includes a fixture in / out slide, a fixture vertical storage unit, an automatic fixture frame, an H-type positioner, and an automatic arc welding station. The clamp loading and unloading slide is used for loading clamps; The size detection device is located in the vicinity of the fixture entry and exit slide table and is used to detect the size of the fixture. When the detection is qualified, the fixture is sent to the second predetermined position. When the detection is unqualified, the gripper is controlled to place the fixture in the first predetermined position. The second predetermined position is the fixture vertical storage. The robot in the size detection equipment is also used to control the gripper to pick up the fixture from the fixture storage and replace it in the automatic fixture frame; An automatic arc welding station is used to perform arc welding operations on the workpieces on the fixture; The H-type positioner is used to rotate the fixture so that the automatic arc welding station can perform arc welding on the workpiece.

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