Precise positioning welding seam tracking device and welding seam tracking auxiliary calibration method

Abstract

The invention relates to a precise positioning welding seam tracking device and a welding seam tracking auxiliary calibration method. The accurate positioning welding seam tracking device comprises a camera shell, a first camera unit, a second camera unit, a third camera unit and a translation track, the first camera unit and the translation track are arranged in the camera shell, and the translation track is arranged beside the first camera unit; the second camera unit and the third camera unit are connected with the translation track in a sliding manner, and the second camera unit and the third camera unit are arranged on the two sides of the first camera unit respectively; and light paths of the first camera unit, the second camera unit and the third camera unit are intersected at the same point. The precise positioning welding seam tracking device and the welding seam tracking auxiliary calibration method have the advantages of being capable of recognizing special welding seams and high in precision and stability.

Description

Technical Field

[0001] The present invention relates to the field of high-precision welding, and in particular to a precise positioning weld tracking device and a weld tracking auxiliary calibration method. Background Art

[0002] With the development of modern welding technology, higher requirements are put forward for automated welding technology and accuracy. In order to improve the measurement accuracy, it is a common method to install a weld tracking camera on the welding gun. At present, most weld tracking cameras use the laser triangulation principle.

[0003] However, when laser triangulation is used in welding of highly reflective materials and welds with small gaps, the laser can hardly be reflected in the height difference of the weld, and there is almost no diffuse reflection of the laser under highly reflective materials. Most of the laser will be directly reflected, making it impossible for the camera to receive all the light, resulting in instability in identifying special welds. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a precise positioning weld tracking device and a weld tracking auxiliary calibration method, which has the advantages of being able to identify highly reflective materials and small special welds, and has high accuracy and stability.

[0005] A precise positioning weld tracking device, characterized in that it includes a camera housing, a first camera unit, a second camera unit, a third camera unit and a translation track; the first camera unit and the translation track are arranged in the camera housing, and the translation track is arranged beside the first camera unit; the second camera unit and the third camera unit are slidably connected to the translation track, and the second camera unit and the third camera unit are respectively arranged on both sides of the first camera unit; a camera port is provided on the camera housing, and the optical paths of the first camera unit, the second camera unit and the third camera unit pass through the camera port and emit out of the camera housing; the optical paths of the first camera unit, the second camera unit and the third camera unit intersect at the same point.

[0006] The precise positioning weld tracking device described in the present invention uses the second camera unit and the third camera unit to assist the first camera unit in calibration, thereby improving recognition accuracy and stability.

[0007] Furthermore, the first camera unit includes a first camera, a first lens, and a first filter in sequence; the optical path of the first camera unit starts from the first camera, passes through the first lens and the first filter in sequence, and is emitted from the camera port; the second camera unit includes a second camera, a second lens, and a first wedge lens in sequence; the optical path of the second camera unit starts from the second camera, passes through the second lens and the first wedge lens in sequence, and is emitted from the camera port; the third camera unit includes a third camera, a third lens, and a second wedge lens in sequence; the optical path of the third camera unit starts from the third camera, passes through the third lens and the second wedge lens in sequence, and is emitted from the camera port.

[0008] Furthermore, the apex angles of the first wedge mirror and the second wedge mirror are opposite to each other and are symmetrically arranged.

[0009] Furthermore, the first camera group, the second camera group and the third camera group also include a light intensity adjustment mechanism; the light intensity adjustment mechanism is respectively arranged in the optical path of each camera group.

[0010] Furthermore, the light intensity adjustment mechanism is any one of a variable aperture and a gradient ND filter.

[0011] Furthermore, the first lens, the second lens and the third lens are macro lenses.

[0012] Furthermore, it also includes a background light source; the background light source is arranged beside the camera port.

[0013] A weld tracking auxiliary calibration method specifically comprises the following steps:

[0014] S1: fix the precise positioning weld tracking device on the welding gun, set the weld calibration plate under the precise positioning weld tracking device, and align the cross coincidence line of the weld calibration plate with the starting point of the weld;

[0015] S2 moves the welding gun, aligns the center of the composite image collected by the precise positioning weld tracking device with the cross coincidence line of the weld calibration plate, and records the coordinates of the welding gun at this time as the first coordinates;

[0016] S3 controls the welding gun to align the welding wire part with the starting point of the weld, records the coordinates of the welding gun at this time, and records them as the second coordinates; calculates the difference between the first coordinate and the second coordinate, and records them as the calibration correction value;

[0017] During the welding process of S4, the weld is tracked and detected with a precise positioning weld tracking device to obtain the detection coordinates; the detection coordinates are corrected using the calibration correction value, and the detection coordinates are corrected to the coordinates of the welding gun, thereby controlling the movement of the welding gun.

[0018] Furthermore, the step S2 specifically includes:

[0019] S21 collects an image of the first camera group, adjusts the position of the welding gun, and aligns the center of the image of the first camera group with the cross coincidence line of the weld calibration plate;

[0020] S22: collecting images of the second camera group and the third camera group to form a composite image; changing the positions of the second camera group and the third camera group on the translation track so that the welds in the images of the second camera group and the third camera group in the composite image overlap;

[0021] S23 adjusts the height of the precise positioning weld tracking device on the welding gun until the welds in the images of the first camera group, the second camera group and the third camera group in the composite image overlap; records the coordinates of the welding gun at this time as the first coordinates.

[0022] Furthermore, the step S2 also includes: binarizing the image sampled by the camera unit, manually sorting out the identification features of the weld, and eliminating other identification features.

[0023] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of a precise positioning weld tracking device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the terms "vertical direction", "up", "down", "horizontal", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a heat-conducting connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, or a connection through an intermediate medium, or the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] Example

[0029] See also Figure 1 The embodiment of the present application provides a precise positioning weld tracking device, comprising a camera housing, a first camera unit 1, a second camera unit 2, a third camera unit 3, and a translation track 4. The first camera unit 1 and the translation track 4 are arranged in the camera housing, the first camera unit 1 and the translation track 4 are relatively fixed, and the translation track 4 is arranged beside the first camera unit 1; the second camera unit 2 and the third camera unit 3 are slidably connected to the translation track 4, and the second camera unit 2 and the third camera unit 3 are respectively located on both sides of the first camera unit 1; the optical paths of the first camera unit 1, the second camera unit 2, and the third camera unit 3 intersect at the same point.

[0030] Furthermore, a camera port is provided on the camera housing, and a protective lens 5 is provided at the camera port, and the optical paths of the first camera unit 1, the second camera unit 2, and the third camera unit 3 pass through the protective lens 5 and are emitted out of the camera housing. In some embodiments, the precise positioning weld tracking device further includes a filter group, which is provided at the camera port and located on one side inside the protective lens 5. In some embodiments, the second camera unit 2 and the third camera unit 3 are symmetrically arranged with the first camera unit 1 as the symmetry axis.

[0031] The first camera assembly 1 sequentially includes a first camera 101, a first lens 102, a light intensity adjustment mechanism 1a and a first filter 103. The light path of the first camera assembly 1 starts from the first camera 101, passes through the first lens 102, the light intensity adjustment mechanism 1a and the first filter 103 in sequence, and then is emitted from the camera port.

[0032] The second camera assembly 2 includes a second camera head 201, a second lens 202, a light intensity adjustment mechanism 1a and a first wedge mirror 203. The light path of the second camera assembly 2 starts from the second camera head 201, passes through the second lens 202, the light intensity adjustment mechanism 1a and the first wedge mirror 203, and then exits from the camera port.

[0033] The third camera assembly 3 sequentially includes a third camera head 301, a third lens 302, a light intensity adjustment mechanism 1a, and a second wedge lens 303. The light path of the third camera assembly 3 starts from the third camera head 301, passes through the third lens 302, the light intensity adjustment mechanism 1a, and the second wedge lens 303, and then is emitted from the camera port.

[0034] Furthermore, the first filter 103 is an NC filter. The apex angles of the first wedge lens 203 and the second wedge lens 303 are opposite to each other and are symmetrically arranged so that the optical paths of the first camera group 1, the second camera group 2 and the third camera group 3 meet at the same point.

[0035] In some embodiments, the first lens 102 , the second lens 202 , and the third lens 302 are macro lenses to achieve precise focusing.

[0036] In some embodiments, the light intensity adjustment mechanism 1a is a variable aperture; in other embodiments, the light intensity adjustment mechanism 1a is a gradient ND filter.

[0037] The precise positioning weld tracking device of the present application adjusts the intensity of light entering each camera through the first filter 103 and each variable aperture.

[0038] Furthermore, the precise positioning weld tracking device also includes a background light source; the background light source is arranged beside the camera port, and in some embodiments, the background light source is a blue 45° light source.

[0039] Furthermore, an embodiment of the present application also provides a weld tracking auxiliary calibration method using the aforementioned precise positioning weld tracking device.

[0040] The weld tracking auxiliary calibration method specifically includes the following steps:

[0041] S1: Fix the precise positioning weld tracking device on the welding gun, set the weld calibration plate under the precise positioning weld tracking device, and align the cross coincidence line of the weld calibration plate with the starting point of the weld.

[0042] S2: Control the welding gun to align the center of the composite image collected by the precise positioning weld tracking device with the cross coincidence line of the weld calibration plate, and record the coordinates of the welding gun at this time as the first coordinate.

[0043] Step S2 specifically includes:

[0044] S21: Collect the image of the first camera unit 1, adjust the position of the welding gun, and align the center of the image of the first camera unit 1 with the cross coincidence line of the weld calibration plate.

[0045] S22: Observe the weld with a precise positioning weld tracking device, collect images of the second camera unit 2 and the third camera unit 3, and form a composite image; control the positions of the second camera unit 2 and the third camera unit 3 on the translation track 4 so that the welds in the images of the second camera unit 2 and the third camera unit 3 in the composite image overlap.

[0046] S23: Adjust the height of the precise positioning weld tracking device on the welding gun until the welds in the images of the first camera group 1, the second camera group 2 and the third camera group 3 in the composite image overlap; record the coordinates of the welding gun at this time as the first coordinate.

[0047] S3: Control the welding gun to align the welding wire part with the starting point of the weld, record the coordinates of the welding gun at this time, and record them as the second coordinates; calculate the difference between the first coordinate and the second coordinate, and record them as the calibration correction value.

[0048] S4: During the welding process of the weld, the weld is tracked and detected by using a precise positioning weld tracking device to obtain the detection coordinates; the detection coordinates are corrected using the calibration correction value, and the detection coordinates are corrected to the coordinates of the welding gun, thereby controlling the movement of the welding gun.

[0049] Furthermore, the above-mentioned coordinates are TCP coordinates (X, Y, Z, U, V, W); wherein X is the coordinate along the tangent direction of the weld, and Y is the coordinate on the plane in a direction perpendicular to the weld.

[0050] Furthermore, step S2 also includes: binarizing the images sampled by the camera assembly, manually sorting out the identification features of the weld, and eliminating other identification features.

[0051] Furthermore, step S4 also includes: when encountering a curved weld, the weld is positioned by the first camera unit 1 to obtain the X direction of the TCP coordinate, the X direction of the TCP coordinate is rotated 90° to correct it to the Y direction, and the required W direction angle is obtained according to the X direction and Y direction of the TCP coordinate, thereby correcting the welding gun angle.

[0052] Furthermore, step S4 also includes: during welding, the light intensity adjustment mechanism 1a in each camera unit is adjusted synchronously according to the exposure of the image collected by each camera unit; for example, the size of the variable aperture is changed according to the exposure of the image to reduce the amount of light entering to reach the set value.

[0053] The precise positioning weld tracking device and weld tracking auxiliary calibration method of the embodiment of the present application can accurately and intuitively obtain the calibration correction value, so as to more conveniently control the welding gun during the welding process; it has high accuracy and stability. And due to the use of visual positioning, it can identify welds with small gaps.

[0054] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and the present invention is also intended to include these modifications and modifications.

Claims

1. A precise positioning weld tracking device, characterized in that: It includes a camera housing, a first camera unit, a second camera unit, a third camera unit and a translation track; the first camera unit and the translation track are arranged in the camera housing, and the translation track is arranged beside the first camera unit; the second camera unit and the third camera unit are slidably connected to the translation track, and the second camera unit and the third camera unit are respectively arranged on both sides of the first camera unit; a camera port is provided on the camera housing, and the optical paths of the first camera unit, the second camera unit and the third camera unit pass through the camera port and emit out of the camera housing; the optical paths of the first camera unit, the second camera unit and the third camera unit intersect at the same point.

2. The precise positioning weld tracking device according to claim 1, characterized in that: The first camera unit includes a first camera, a first lens, and a first filter in sequence; the optical path of the first camera unit starts from the first camera, passes through the first lens and the first filter in sequence, and is emitted from the camera port; the second camera unit includes a second camera, a second lens, and a first wedge lens in sequence; the optical path of the second camera unit starts from the second camera, passes through the second lens and the first wedge lens in sequence, and is emitted from the camera port; the third camera unit includes a third camera, a third lens, and a second wedge lens in sequence; the optical path of the third camera unit starts from the third camera, passes through the third lens and the second wedge lens in sequence, and is emitted from the camera port.

3. The precise positioning weld tracking device according to claim 2, characterized in that: The apex angles of the first wedge mirror and the second wedge mirror are opposite to each other and are symmetrically arranged.

4. The precise positioning weld tracking device according to claim 2, characterized in that: The first camera group, the second camera group and the third camera group further include a light intensity adjustment mechanism; the light intensity adjustment mechanism is respectively arranged in the optical path of each camera group.

5. The precise positioning weld tracking device according to claim 4, characterized in that: The light intensity adjustment mechanism is a variable aperture or a gradient ND filter.

6. The precise positioning weld tracking device according to claim 2, characterized in that: The first lens, the second lens and the third lens are macro lenses.

7. The precise positioning weld tracking device according to claim 2, characterized in that: It also includes a background light source; the background light source is arranged beside the camera port.

8. A weld tracking auxiliary calibration method, characterized in that: Using the precise positioning weld tracking device described in any one of claims 1 to 7 specifically comprises the following steps: S1: fix the precise positioning weld tracking device on the welding gun, set the weld calibration plate under the precise positioning weld tracking device, and align the cross coincidence line of the weld calibration plate with the starting point of the weld; S2 moves the welding gun, aligns the center of the composite image collected by the precise positioning weld tracking device with the cross coincidence line of the weld calibration plate, and records the coordinates of the welding gun at this time as the first coordinates; S3 controls the welding gun to align the welding wire part with the starting point of the weld, records the coordinates of the welding gun at this time, and records them as the second coordinates; calculates the difference between the first coordinate and the second coordinate, and records them as the calibration correction value; During the welding process of S4, the weld is tracked and detected with a precise positioning weld tracking device to obtain the detection coordinates; the detection coordinates are corrected using the calibration correction value, and the detection coordinates are corrected to the coordinates of the welding gun, thereby controlling the movement of the welding gun.

9. The weld tracking auxiliary calibration method according to claim 8, characterized in that: The step S2 specifically includes: S21 collects an image of the first camera group, adjusts the position of the welding gun, and aligns the center of the image of the first camera group with the cross coincidence line of the weld calibration plate; S22: collecting images of the second camera group and the third camera group to form a composite image; changing the positions of the second camera group and the third camera group on the translation track so that the welds in the images of the second camera group and the third camera group in the composite image overlap; S23 adjusts the height of the precise positioning weld tracking device on the welding gun until the welds in the images of the first camera group, the second camera group and the third camera group in the composite image overlap; records the coordinates of the welding gun at this time as the first coordinates.

10. The weld tracking auxiliary calibration method according to claim 9, characterized in that: The step S2 also includes: binarizing the image sampled by the camera assembly, manually sorting out the identification features of the weld, and eliminating other identification features.

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