Welding gun posture recognition device and method based on three-line laser vision sensor device

Abstract

The present invention relates to the technical field of robots, specifically a welding torch pose recognition device and method based on a three-line laser vision sensing device. The first vertical laser stripe emitter, the second vertical laser stripe emitter, and the horizontal laser stripe emitter are all parallel to the CCD, and the emitted laser stripes are projected onto a vertical steel plate and distributed in a "艹" shape. The position of the laser stripe projected by the vertical laser stripe emitter onto the horizontal steel plate in the weld image has a one-to-one correspondence with the height of the welding torch; the slope of the horizontal laser stripe projected onto the vertical steel plate in the weld image reflects the inclination angle of the welding torch along the welding direction; the position of the laser stripe projected by the vertical laser stripe emitter onto the vertical steel plate in the weld image is related to the horizontal deviation of the welding torch relative to the weld; the present invention helps to realize the automatic machine welding of fillet welds, can improve the welding quality and efficiency, and can generate significant economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and particularly to a welding torch pose recognition device and method based on a three-line laser vision sensing device. Background Art

[0002] Welding is one of the cheapest and most effective ways of metal connection. However, the working environment during welding is very harsh, which is not conducive to the physical health of workers. There is an urgent need to realize welding automation, replace manual welding with machines, improve welding quality, and reduce the labor intensity of workers. In order to achieve automatic welding by machines, it is necessary to detect the pose of the welding torch relative to the weld seam, including the height of the welding torch, the horizontal deviation of the welding torch relative to the weld seam, and the inclination angle of the welding torch along the welding direction. Therefore, there is an urgent need for a welding torch pose recognition device and method based on a three-line laser vision sensing device. Summary of the Invention

[0003] (1) Technical Problems to be Solved

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art. The present invention provides a welding torch pose recognition device and method based on a three-line laser vision sensing device, which can realize the automatic detection of the height of the welding torch, the horizontal deviation of the welding torch relative to the weld seam, and the inclination angle of the welding torch along the welding direction, and helps to improve the quality and efficiency of automatic fillet welding.

[0005] (2) Technical Solutions

[0006] The technical solution of the present invention: A welding torch pose recognition device based on a three-line laser vision sensing device includes a three-line laser vision sensing device, a horizontal slider, a welding torch, a vertical steel plate, a horizontal steel plate, and a connecting block. Among them, the three-line laser vision sensing device includes a first vertical laser stripe emitter, a second vertical laser stripe emitter, a horizontal laser stripe emitter, a CCD (Charge Coupled Device, a charge-coupled device image sensor), and a housing. The CCD is arranged on the inner bottom wall of the housing, and the first vertical laser stripe emitter and the second vertical laser stripe emitter are arranged on both sides of the CCD, respectively used for emitting vertical laser stripes. The horizontal laser stripe emitter is located on the inner top wall of the housing and is used for emitting horizontal laser stripes. The first vertical laser stripe emitter, the second vertical laser stripe emitter, and the horizontal laser stripe emitter are all parallel to the CCD. When the emitted laser stripes are projected onto the vertical steel plate, the distribution of the laser stripes is in the shape of a "plus" sign. The three-line laser vision sensing device is connected to the horizontal slider through the connecting block, and the connecting block is connected to the welding torch. The welding torch is aligned with the weld seam at the intersection of the horizontal steel plate and the vertical steel plate. Using this device, the recognition of the pose of the welding torch relative to the weld seam can be realized.

[0007] Further, the first vertical laser stripe emitter is closer to the welding torch, and the second vertical laser stripe emitter is farther from the welding torch.

[0008] Further, an attenuation sheet and a filter are arranged in front of the CCD to filter out background light and arc light and reduce the brightness of the laser stripes in the weld image.

[0009] Further, a glass window sheet is also arranged in front of the CCD to prevent the influence of spatter on the CCD.

[0010] A method for identifying the pose of a welding torch based on a three-line laser vision sensing device includes a three-line laser vision sensing device, a principle for detecting the height of the welding torch based on the features of the three-line laser vision sensing image, a principle for detecting the inclination angle of the welding torch along the welding direction based on the features of the three-line laser vision sensing image, and a principle for detecting the horizontal deviation of the welding torch relative to the weld seam based on the features of the three-line laser vision sensing image. The first vertical laser stripe emitter, the second vertical laser stripe emitter, the horizontal laser stripe emitter, and the CCD in the three-line laser vision sensing device are parallel to each other. When the emitted laser stripes are projected onto a vertical steel plate, the distribution of the laser stripes is in the shape of a "plus" sign.

[0011] Further, the principle for detecting the height of the welding torch based on the features of the three-line laser vision sensing image is as follows: There is a one-to-one correspondence between the position of the laser stripe projected by the first vertical laser stripe emitter onto the horizontal steel plate in the weld image and the height of the welding torch. Their relationship is as follows,

[0012] h = A·a + B

[0013] In the formula, h is the height of the welding torch; a represents the position of the laser stripe projected by the first vertical laser stripe emitter onto the horizontal steel plate in the weld image; A and B are both constant coefficients.

[0014] Based on the above relationship, the height of the welding torch can be detected.

[0015] Further, the principle for detecting the inclination angle of the welding torch along the welding direction based on the features of the three-line laser vision sensing image is as follows: When the horizontal laser stripe is projected onto the vertical steel plate, the magnitude of the slope k of it in the weld image reflects the magnitude of the inclination angle. The positive and negative of the slope respectively reflect whether the welding torch is tilted forward or backward along the welding direction. The following relationship is satisfied between this slope and the inclination angle of the welding torch along the welding direction,

[0016] θ = C·k + D

[0017] In the formula, θ is the inclination angle of the welding torch along the welding direction; k is the slope of the horizontal laser stripe projected onto the vertical steel plate in the weld image; C and D are both constant coefficients.

[0018] Based on the above relationship, the inclination angle of the welding torch along the welding direction can be detected.

[0019] Furthermore, the principle for detecting the horizontal deviation of the welding torch relative to the weld seam based on the image features of the three-line laser vision sensing is as follows: The position of the laser stripe projected by the second vertical laser stripe emitter onto the vertical steel plate in the weld seam image is related to the horizontal deviation of the welding torch relative to the weld seam. At the same time, the horizontal deviation of the welding torch relative to the weld seam is also related to the inclination angle of the welding torch along the welding direction. Their relationship is as follows.

[0020] e = E·d + F·k + G

[0021] In the formula, e is the horizontal deviation of the welding torch relative to the weld seam; k is the slope of the horizontal laser stripe projected onto the vertical steel plate in the weld seam image, which can represent the inclination angle of the welding torch along the welding direction; d is the position of the laser stripe projected by the second vertical laser stripe emitter onto the vertical steel plate in the weld seam image; E, F, and G are all coefficients.

[0022] Based on the above relationship, the horizontal deviation of the welding torch relative to the weld seam can be detected.

[0023] (III) Beneficial effects

[0024] The advantages of the present invention are as follows: The distribution of the laser stripes is in a "plus" shape, with more laser stripes, so that the weld seam image contains more information reflecting the pose of the welding torch. Based on the three-line laser vision sensing technology, a mathematical model from the weld seam image features to the welding torch pose is established, which can simultaneously detect the height of the welding torch, the horizontal deviation of the welding torch relative to the weld seam, and the inclination angle of the welding torch along the welding direction, helping to improve the quality and efficiency of automatic fillet welding. Description of the drawings

[0025] Figure 1 It is a schematic structural diagram of the present invention.

[0026] Figure 2 It is a mathematical model of the three-line laser vision sensing weld seam image of the present invention.

[0027] Figure 3 It is a weld seam image collected by the three-line laser vision sensing device of the present invention.

[0028] Reference numerals: 1. Horizontal slider, 2. Welding torch, 3. Weld seam, 4. Vertical steel plate, 5. Horizontal steel plate, 6. Second vertical laser stripe emitter, 7. CCD, 8. First vertical laser stripe emitter, 9. Outer shell, 10. Horizontal laser stripe emitter, 11. Connecting block. Specific implementation manners

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] Embodiment 1. Please refer to Figure 1 , a welding torch pose recognition device based on a three-line laser vision sensing device, includes a three-line laser vision sensing device, a horizontal slider 1, a welding torch 2, a vertical steel plate 4, a horizontal steel plate 5, and a connecting block 11. Among them, the three-line laser vision sensing device includes a first vertical laser stripe emitter 8, a second vertical laser stripe emitter 6, a horizontal laser stripe emitter 10, a CCD 7, and a housing 9. The CCD 7 is provided on the inner wall of the bottom of the housing 9, and the first vertical laser stripe emitter 8 and the second vertical laser stripe emitter 6 are provided on both sides of the CCD 7. The one closer to the welding torch 2 is the first vertical laser stripe emitter 8, and the one farther from the welding torch 2 is the second vertical laser stripe emitter 6, which are respectively used to emit vertical laser stripes. The horizontal laser stripe emitter 10 is located on the inner top wall of the housing 9 and is used to emit horizontal laser stripes. An attenuation sheet and a filter are provided in front of the CCD 7 to filter out background light and arc light and reduce the brightness of the laser stripes in the weld image. A glass window sheet is also provided in front of the CCD 7 to prevent the influence of spatter on the CCD 7. The first vertical laser stripe emitter 8, the second vertical laser stripe emitter 6, and the horizontal laser stripe emitter 10 are all parallel to the CCD 7. When the emitted laser stripes are projected onto the vertical steel plate 4, the distribution of the laser stripes is in the shape of "卄". The three-line laser vision sensing device is connected to the horizontal slider 1 through the connecting block 11, and the connecting block 11 is connected to the welding torch 2. The welding torch 2 is aligned with the weld at the intersection of the horizontal steel plate 5 and the vertical steel plate 4. With this device, the pose recognition of the welding torch 2 relative to the weld 3 can be realized.

[0031] A welding torch pose recognition method based on a three-line laser vision sensing device includes a three-line laser vision sensing device, a welding torch height detection principle based on the characteristics of the three-line laser vision sensing image, a welding torch inclination detection principle along the welding direction based on the characteristics of the three-line laser vision sensing image, and a horizontal deviation detection principle of the welding torch relative to the weld based on the characteristics of the three-line laser vision sensing image. The first vertical laser stripe emitter 8, the second vertical laser stripe emitter 6, the horizontal laser stripe emitter 10, and the CCD 7 in the three-line laser vision sensing device are parallel to each other. When the emitted laser stripes are projected onto the vertical steel plate 4, the distribution of the laser stripes is in the shape of

[0032] Furthermore, the welding gun height detection principle based on the three-line laser visual sensing image feature is as follows: the position of the laser stripe projected by the first vertical laser stripe emitter 8 onto the horizontal steel plate 5 in the weld image has a one-to-one correspondence with the height of the welding gun 2, and the relationship between them is as follows:

[0033] h=A·a+B

[0034] Wherein, h is the height of the welding gun 2; a represents the position of the laser stripe projected by the first vertical laser stripe emitter onto the horizontal steel plate in the weld image; A and B are both constant coefficients. Based on the above relationship, the height of the welding gun 2 can be detected.

[0035] Furthermore, the principle of detecting the inclination of the welding gun along the welding direction based on the three-line laser visual sensor image feature is as follows: the horizontal laser stripe is projected onto the vertical steel plate, and the size of its slope k on the weld image reflects the size of the inclination, and the positive and negative slopes respectively reflect that the welding gun is tilted forward or backward along the welding direction, and the slope and the inclination of the welding gun along the welding direction satisfy the following relationship:

[0036] θ=C·k+D

[0037] Wherein, θ is the inclination angle of the welding gun along the welding direction; k is the slope of the horizontal laser stripe projected onto the vertical steel plate on the weld image; C and D are both constant coefficients. Based on the above relationship, the inclination angle of the welding gun along the welding direction can be detected.

[0038] Furthermore, the principle of detecting the horizontal deviation of the welding gun relative to the weld based on the three-line laser visual sensing image feature is as follows: the position of the laser stripe projected by the second vertical laser stripe emitter 6 onto the vertical steel plate 4 in the weld image is related to the horizontal deviation of the welding gun relative to the weld. At the same time, the horizontal deviation of the welding gun relative to the weld is also related to the inclination angle of the welding gun along the welding direction. The relationship between them is as follows:

[0039] e=E·d+F·k+G

[0040] Wherein, e is the horizontal deviation of the welding gun relative to the weld; k is the slope of the horizontal laser stripe projected onto the vertical steel plate on the weld image, which can characterize the inclination of the welding gun along the welding direction; d is the position of the laser stripe projected onto the vertical steel plate by the second vertical laser stripe emitter in the weld image; E, F and G are all coefficients. Based on this relationship, the horizontal deviation of the welding gun relative to the weld can be detected.

[0041] When the welding gun 2 has no inclination along the welding direction, the distance between the left vertical laser emitter 8 and the welding point along the welding direction is 46 mm, and the distance between the left vertical laser emitter 8 and the right vertical laser emitter 6 along the welding direction is 54 mm. Figure 1 Point O, point E and point F are points on the weld 3, point O is the current welding point, point E is the intersection of the left vertical laser stripe and the weld 3, and point F is the intersection of the right vertical laser stripe and the weld 3.

[0042] After the weld image is collected by CCD7, the linear equation of the center line of each laser stripe and the coordinates of each feature point in the weld image are obtained. Taking the weld image collected when the welding posture is continuous weld 3 as an example, a mathematical model of the weld image is established, as shown in Figure 2 As shown in Figure 1, the weld image is generally composed of two vertical stripes CE and DF and three oblique stripes AE, BF and GH. The following study is the relationship between the characteristic variables in the weld image and the welding system posture when the inclination angle of the welding gun 2 in the vertical plane is fixed. Since the oblique stripe AE is on the horizontal steel plate 5, Figure 2 The a value will not change with the inclination and horizontal deviation of the welding gun 2 along the welding direction. When the inclination of the welding gun 2 in the vertical plane is constant, its value has a one-to-one correspondence with the height of the welding gun 2. When the stripe GH is on the vertical steel plate 4, its slope does not change with the height and horizontal deviation of the welding gun 2. Only when the welding gun 2 has an inclination along the welding direction, the relative position relationship between CCD7 and the horizontal stripe changes, causing the slope k of the stripe GH in the weld image to change. The size of the slope reflects the size of the inclination, and the positive and negative values ​​of the slope respectively reflect that the welding gun 2 is tilted forward or backward along the welding direction.

[0043] The mathematical model for establishing the relationship between the weld image and the position of welding gun 2 relative to weld 3 is as follows:

[0044]

[0045] Where, e is the horizontal deviation, h is the height of welding gun 2, and θ is the inclination angle of welding gun 2 along the welding direction. These three variables reflect the posture of welding gun 2 relative to weld 3; d, a, and k are the features in the weld image, and their meanings are as follows: Figure 2 As shown; A, B, C, D, E, F and G are coefficients.

[0046] The values ​​of the parameters of the transformation matrix in formula (1) are calculated, and the features in the weld image are converted into features that characterize the position of the automatic welding system relative to the weld 3 through the transformation matrix. Finally, the position of the welding gun 2 relative to the weld 3 can be identified based on the three-line laser vision sensor device, which helps to improve the quality and efficiency of welding.

[0047] like Figure 3As shown, it is a weld image collected by the three-line laser vision sensing device of the present invention. By using the device and method of the present invention, it can be identified that the welding gun 2 is tilted backward by 30° along the welding direction, the height of the welding gun 2 is 13 mm, and the horizontal welding deviation is 1 mm (the welding gun 2 deviates to the left from the weld 3 along the welding direction). Therefore, by using the device and method of the present invention, the position of the welding gun 2 relative to the weld 3 can be accurately identified.

[0048] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0049] The above only expresses the preferred embodiments of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for ordinary technicians in this field, several modifications, improvements and substitutions can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A welding gun posture recognition device based on a three-line laser vision sensor device, characterized in that: It includes a three-line laser vision sensing device, a horizontal slider (1), a welding torch (2), a vertical steel plate (4), a horizontal steel plate (5) and a connecting block (11); wherein, the three-line laser vision sensing device includes a first vertical laser stripe emitter (8), a second vertical laser stripe emitter (6), a horizontal laser stripe emitter (10), a CCD (7) and a housing (9). The CCD (7) is arranged on the inner wall of the bottom of the housing (9). The first vertical laser stripe emitter (8) and the second vertical laser stripe emitter (6) are arranged on both sides of the CCD (7) respectively for emitting vertical laser stripes. The horizontal laser stripe emitter (10) is located on the inner top wall of the housing (9) for emitting a horizontal laser stripe. The first vertical laser stripe emitter (8), the second vertical laser stripe emitter (6) and the horizontal laser stripe emitter (10) are all parallel to the CCD (7). When the emitted laser stripes are projected onto the vertical steel plate (4), the distribution of the laser stripes is in the shape of "卄"; the three-line laser vision sensing device is connected to the horizontal slider (1) through the connecting block (11), and the connecting block (11) is connected to the welding torch (2), and the welding torch (2) is aligned with the weld at the intersection of the horizontal steel plate (5) and the vertical steel plate (4).

2. A welding gun posture recognition method based on a three-line laser vision sensor device is characterized in that: Using the recognition device as described in Claim 1 to recognize the pose of the welding torch, including: based on the fact that the first vertical laser stripe emitter (8), the second vertical laser stripe emitter (6) and the horizontal laser stripe emitter (10) in the three-line laser vision sensing device are all parallel to the CCD (7), when the emitted laser stripes are projected onto the vertical steel plate (4), the distribution of the laser stripes is in the shape of "卄"; Detecting the height of the welding torch (2) based on the welding torch height detection principle of the three-line laser vision sensing image features; Detecting the inclination angle of the welding torch (2) along the welding direction based on the welding torch inclination angle detection principle along the welding direction of the three-line laser vision sensing image features; Detecting the horizontal deviation of the welding torch (2) relative to the weld based on the horizontal deviation detection principle of the welding torch relative to the weld of the three-line laser vision sensing image features; Establishing the following mathematical model for the relationship between the weld image and the pose of the welding torch (2) relative to the weld (3), ， In the formula, is the horizontal deviation, is the height of the welding gun (2), is the inclination angle of the welding gun (2) along the welding direction. These three variables reflect the posture of the welding gun (2) relative to the weld (3); , and is the feature in the weld image; A , B , C , D , E , F and G All are coefficients.

3. The welding gun posture recognition method based on the three-line laser vision sensor device according to claim 2 is characterized in that: The position of the laser stripe projected by the first vertical laser stripe emitter (8) onto the horizontal steel plate (5) in the weld (3) image has a one-to-one correspondence with the height of the welding torch (2), and the relationship is as follows: In the formula, is the height of the welding gun; Indicates the position of the laser stripes projected by the first vertical laser stripe emitter (8) onto the horizontal steel plate (5) in the weld seam (3) image; A and B are constant coefficients, so that the height of the welding gun (2) can be detected.

4. The welding gun posture recognition method based on the three-line laser vision sensor device according to claim 2 is characterized in that: The slope of the laser stripe projected by the horizontal laser stripe emitter (10) onto the vertical steel plate (4) on the weld seam (3) image The size of reflects the size of the inclination angle of the welding gun along the welding direction. The positive and negative slopes respectively reflect the forward or backward tilt of the welding gun along the welding direction. The slope and the inclination angle of the welding gun (2) along the welding direction satisfy the following relationship: In the formula, is the inclination angle of the welding gun (2) along the welding direction; is the slope of the laser stripe projected by the horizontal laser stripe transmitter (10) onto the vertical steel plate (4) on the weld (3) image; C and D are constant coefficients.

5. The welding gun posture recognition method based on the three-line laser vision sensor device according to claim 2 is characterized in that: The position of the laser stripe projected by the second vertical laser stripe emitter (6) onto the vertical steel plate (4) in the weld (3) image is related to the horizontal deviation of the welding torch (2) relative to the weld (3). At the same time, the horizontal deviation of the welding torch (2) relative to the weld (3) is also related to the inclination angle of the welding torch (2) along the welding direction. The relationship is as follows, In the formula, is the horizontal deviation of the welding gun (2) relative to the weld (3); The slope of the horizontal laser stripe projected by the horizontal laser stripe emitter (10) onto the vertical steel plate (4) on the weld (3) image can represent the inclination angle of the welding gun (2) along the welding direction; is the position of the laser stripe projected by the second vertical laser stripe emitter (6) onto the vertical steel plate (4) in the weld seam (3) image; E, F and G are coefficients, so that the horizontal deviation of the welding gun (2) relative to the weld seam (3) can be detected.

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