Ultrasonic nondestructive testing defect location tracing method

Abstract

The present invention discloses a method for tracing defect positions in ultrasonic nondestructive testing, which comprises the following steps: ultrasonically scanning a workpiece, and position-encoding the scanning trajectory path to obtain scanning signal data and coded position data; generating an image according to the scanning signal data and the coded position data; finding and selecting the defect position on the image, and obtaining the coded position corresponding to the center of the selected image area; tracing back to the defect position actually corresponding to the workpiece according to the coded position corresponding to the center of the selected image area. The present invention can first perform an overall scan on the workpiece during nondestructive testing. Although the overall scan is time-consuming, no professional personnel are required to participate in the whole process. After the scanning is completed, the defect position is found, and then according to the coded position corresponding to the defect position, the defect position point of the workpiece can be reached after scanning, and then operations such as marking, repairing or re-inspection are performed, which is conducive to improving detection efficiency and reducing costs.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic nondestructive testing, and in particular to a defect position tracing method for ultrasonic nondestructive testing. Background Art

[0002] Ultrasonic nondestructive testing is a method of material testing based on ultrasonic technology. It mainly uses the characteristics of ultrasound generated by ultrasonic probes to penetrate deep into the material of the object and reflect at the edge of the interface when entering another section from one section to another. When the ultrasonic beam passes from the surface of the part through the probe to the inside of the metal, reflected waves are generated when encountering defects and the bottom of the part. The ultrasonic detector obtains these reflected waves from the ultrasonic probe to form data and pictures, and the location and size of the defect are judged based on these data and pictures. When performing ultrasonic nondestructive testing, it is often necessary to carry an ultrasonic probe and move it along the surface of the workpiece to scan. When scanning to a defective position, it is often necessary to stop scanning, mark or repair the defective position of the workpiece, and then continue scanning; scanning the workpiece often takes a lot of time, especially when the workpiece is large in size, and processing the scanned data and identifying the defect location often requires the full participation of professionals, which will greatly affect the efficiency of ultrasonic nondestructive testing and waste human resource costs. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a defect position tracing method for ultrasonic non-destructive testing, which can first perform a comprehensive scan on the workpiece, and then find the defect position and trace back to the defect position after the scanning is completed, thereby improving the detection efficiency.

[0004] The ultrasonic nondestructive testing defect position tracing method according to an embodiment of the present invention comprises the following steps:

[0005] Perform ultrasonic scanning on the workpiece and position encode the scanning trajectory path to obtain scanning signal data and encoded position data;

[0006] generating an image based on the scan signal data and the encoded position data;

[0007] Find and select the defect location on the image, and obtain the coded location corresponding to the center of the selected image area;

[0008] According to the encoding position corresponding to the center of the selected image area, trace back to the actual corresponding defect position of the workpiece.

[0009] The ultrasonic nondestructive testing defect position tracing method according to the embodiment of the present invention has at least the following beneficial effects: by encoding the scanning trajectory path in real time during the scanning of the workpiece, after the scanning is completed, the image data generated according to the scanning signal data and the encoding position data will correspond to the encoding data position, and when a defect is found in the image later, the image of the defect position is directly selected to obtain the encoding position corresponding to the center of the selected image area, and finally, according to the encoding position data, the corresponding device is driven in turn to the position where the defect actually occurs on the workpiece to complete the tracing; through the ultrasonic nondestructive testing defect position tracing method provided by this embodiment, the workpiece can be scanned as a whole during the nondestructive testing process. Although the overall scanning is time-consuming, no professional personnel are required to participate in the whole process. After the scanning is completed, the defect position is found in the image, and then according to the corresponding encoding position, the ultrasonic probe, marking equipment or repair device can be brought to the defect position point of the workpiece after scanning, and then marking, repair or re-inspection operations can be performed, which is conducive to improving detection efficiency and reducing costs.

[0010] According to some embodiments of the present invention, finding and selecting a defect location in an image includes the following steps: the image is displayed on a screen, an operator interprets the image, and draws a frame at the location where the defect exists in the image for selection.

[0011] According to some embodiments of the present invention, finding and selecting a defect location in an image includes the following steps: presetting a defect image area; extracting a color region that is different from a non-defective region through color and / or threshold segmentation; determining whether the area of ​​the extracted color region exceeds the preset defect image area, and if so, performing external graphic fitting on the segmented color region to form a frame for frame selection.

[0012] According to some embodiments of the present invention, when the area of ​​the extracted color region does not exceed the preset defect image area, the operator interprets the image on the screen and draws a frame at the location where the defect exists in the image for selection.

[0013] According to some embodiments of the present invention, color areas that are different from defect-free areas are extracted through color and / or threshold segmentation, including the following steps: using image space to convert the image into a black and white picture by setting hue, saturation, and brightness values; setting a threshold based on the converted black and white picture to extract the bright area in the picture.

[0014] According to some embodiments of the present invention, performing external graphic fitting on the extracted color area to form a frame includes the following steps: finding the maximum and minimum values ​​of X and Y in all pixels in the bright area, and using the maximum and minimum values ​​of X and Y as boundaries as rectangular boundaries.

[0015] According to some embodiments of the present invention, an ultrasonic non-destructive scanning device is used for ultrasonic scanning. The ultrasonic non-destructive scanning device includes an ultrasonic probe and a transfer mechanism. The end of the transfer mechanism is connected to the ultrasonic probe for driving the ultrasonic probe to scan and move.

[0016] According to some embodiments of the present invention, ultrasonic scanning of a workpiece and position encoding of the scanning trajectory path include the following steps: simultaneously recording the position data of the end of the current transfer mechanism in the transfer mechanism coordinate system, and storing it in one-to-one correspondence with the encoded position data;

[0017] According to the coding position corresponding to the center of the selected image area, tracing back to the actual defect position of the workpiece includes the following steps: obtaining the position in the transfer mechanism coordinate system corresponding to the coding position corresponding to the center of the selected image area, and controlling the end of the transfer mechanism to move to this position.

[0018] According to some embodiments of the present invention, the transfer mechanism is slidably disposed on the ground rail; the workpiece is ultrasonically scanned and the scanning trajectory path is position-encoded, and the following steps are also included: simultaneously recording the ground rail position data where the transfer mechanism is currently located, and storing it in one-to-one correspondence with the coded position data;

[0019] According to some embodiments of the present invention, based on the coded position corresponding to the center of the selected image area, tracing back to the actual corresponding defect position of the workpiece includes the following steps: obtaining the ground rail position corresponding to the coded position corresponding to the center of the selected image area, and controlling the transfer mechanism to move to this position.

[0020] According to some embodiments of the present invention, ultrasonic scanning of a workpiece and position coding of the scanning trajectory path include the following steps: dividing the workpiece into several areas and numbering them; and ultrasonically scanning and position coding the scanning trajectory path for areas with different numbers respectively.

[0021] According to some embodiments of the present invention, ultrasonic scanning of a workpiece and position encoding of the scanning trajectory path further include the following steps:

[0022] Each area of ​​the workpiece is profiled and scanned according to the surface contour of the workpiece, and each scanning position in the scanning trajectory is converted into the coordinates of the workpiece profiling plane for encoding.

[0023] According to some embodiments of the present invention, after tracing back to the defect position actually corresponding to the workpiece, the following steps are also included:

[0024] Spray marking and / or repairing of defective parts of workpieces.

[0025] According to some embodiments of the present invention, the following steps are also included:

[0026] A model of the workpiece and the ultrasonic non-destructive scanning device is established, and the scanning trajectory path of the workpiece surface is planned through offline simulation.

[0027] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0029] Figure 1 It is a schematic diagram of the process of the ultrasonic nondestructive testing defect position tracing method of the present invention;

[0030] Figure 2 A schematic diagram of a flow chart of a method for tracing defect positions in ultrasonic nondestructive testing according to an embodiment of the present invention;

[0031] Figure 3 A schematic diagram of a flow chart of a method for tracing defect positions in ultrasonic nondestructive testing according to another embodiment of the present invention;

[0032] Figure 4 A schematic diagram of a flow chart of a method for tracing defect positions in ultrasonic nondestructive testing according to another embodiment of the present invention;

[0033] Figure 5 A schematic diagram of a scanning method in a small area in an embodiment of the present invention;

[0034] Figure 6 It is a schematic structural diagram of an ultrasonic non-destructive scanning device connected to a slide table in an embodiment of the present invention.

[0035] Reference numerals:

[0036] The robot 10 , the slide 20 , the slide drive device 30 , and the ultrasonic probe 40 . DETAILED DESCRIPTION

[0037] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0038] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, left, right, front, back, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying 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 should not be understood as a limitation on the present invention.

[0039] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0040] Reference Figure 1 According to the ultrasonic nondestructive testing defect position tracing method of the embodiment of the present invention, the following steps are included:

[0041] S100, performing ultrasonic scanning on the workpiece, and performing position encoding on the scanning trajectory path to obtain scanning signal data and encoding position data;

[0042] S200, generating an image according to the scanning signal data and the encoding position data;

[0043] S300, finding and selecting a defect position on the image, and obtaining a coding position corresponding to the center of the selected image area;

[0044] S400, tracing back to the defect position actually corresponding to the workpiece according to the encoding position corresponding to the center of the selected image area.

[0045] By encoding the scanning trajectory path in real time during the scanning process of the workpiece, after the scanning is completed, the image data generated according to the scanning signal data and the encoded position data will correspond to the position encoding data. When defects are found in the image later, the image of the defective position is directly selected to obtain the encoding position corresponding to the center of the selected image area. Finally, based on this encoding position, the corresponding device is driven in turn to the actual defective position on the workpiece to complete the backtracking.

[0046] Through the ultrasonic non-destructive testing defect position backtracking method provided in this embodiment, the workpiece can be scanned as a whole during the non-destructive testing process. Although the overall scan is time-consuming, no professional personnel are required to participate in the entire process. After the scan is completed, the defect position can be found in the image, and then according to the coded position, the ultrasonic probe 40, marking equipment or repair device can be brought to the defect position point of the workpiece after scanning, and then marking, repair or re-inspection operations can be performed, which is beneficial to improving detection efficiency and reducing costs.

[0047] Reference Figure 2In some embodiments of the present invention, in step S300, finding and selecting defect locations in an image includes the following manual selection step S310:

[0048] The image is displayed on the screen, and the operator interprets the image and draws a frame around the location of the defect in the image for selection.

[0049] Specifically, the image is displayed on the screen, the operator interprets the image, draws a frame at the position where the defect exists in the image, and then obtains the coding position according to the center of the image corresponding to the drawn frame. Moreover, in this embodiment, for the convenience of operation, the frame is drawn in the form of a rectangular frame drawn on the screen by a mouse, and the defect position is located within the rectangular frame. Of course, according to actual conditions, in some other embodiments of the present invention, when the display screen is a touch screen, the frame can also be drawn directly by touch screen; and according to actual conditions, in some other embodiments of the present invention, in addition to a rectangular frame, the frame can also be a triangular frame, a circular frame or other types of closed graphics.

[0050] Reference Figure 3 In some other embodiments of the present invention, in step 300, the defect position is found and selected in the image, and the following automatic selection step S320 is also included:

[0051] Preset the defect image area; extract the color area different from the defect-free area through color and / or threshold segmentation; determine whether the area of ​​the extracted color area exceeds the preset defect image area, and if so, perform external graphic fitting on the segmented color area to form a frame for frame selection.

[0052] Specifically, first, a value of the defect image area is preset. Since defects of smaller size will not affect the normal use of the workpiece, setting this value can eliminate the influence of small-size defects on the ultrasonic non-destructive testing results. Then, the image is segmented by color and / or threshold, so as to extract the color area different from the defect-free area. Since the color of the defect position in the image is obviously different from the defect-free area, the extracted color area will correspond to the defect area; the area of ​​the extracted color area is compared with the preset value of the defect image area. If it exceeds, the extracted color area is fitted with an external graph to complete the selection.

[0053] Furthermore, the image is segmented by color and / or threshold value, so as to extract the color area different from the defect-free area. Specifically, the following method can be adopted: using the image space, the image is converted into a black and white picture by setting the hue, saturation and brightness values, and then according to the converted black and white picture, the threshold is set again to extract the bright area in the image. At this time, the extracted bright area is the corresponding defect area.

[0054] Optionally, the image space is selected to use HSL image space. Of course, according to actual conditions, in some other embodiments, other types of color spaces such as HSV image space and RGB image space may also be selected to be used.

[0055] Furthermore, in order to simplify the process of external graphics fitting, external graphics fitting is performed on the extracted color area. Specifically, the following method can be used: find the maximum and minimum values ​​of X and Y in all pixels of the selected bright area, and use the maximum and minimum values ​​of X and Y as the boundaries to form a rectangular frame, thereby completing the selection.

[0056] Of course, according to actual conditions, in addition to the above-mentioned fitting method to form a rectangular frame, in some other embodiments of the present invention, the fitted figure can also be other closed figures such as a rectangular frame, a triangular frame or a circular frame.

[0057] Reference Figure 4 In some other embodiments of the present invention, in step S300, the defect position is found and selected in the image. In addition to the above-mentioned two selection steps of manual selection and automatic selection, a method of first automatic selection and then manual selection can also be selected, which includes the following steps:

[0058] Specifically, a defect image area is preset; a color area different from a non-defective area is extracted through color and / or threshold segmentation; it is determined whether the area of ​​the extracted color area exceeds the preset defect image area; if it exceeds, an external graphic fitting is performed on the segmented color area to form a frame for selection; if it does not exceed, the operator interprets the image on the screen and draws a frame at the position where the defect exists in the image for selection.

[0059] First, the step S320 above is performed, regarding the step of "preset defect image area, extract the color area that is different from the non-defective area by color and / or threshold segmentation"; subsequently, if the area of ​​the extracted color area exceeds the preset defect image area value, the step is exactly the same as the above step S320; if the area of ​​the extracted color area does not exceed the preset defect image area value, the same step as the above step S310 is performed again. Since the process of automatically executing program selection is relatively rigid and prone to some misjudgments, the above-mentioned method of combining automatic and manual selection, using manual selection as a supplement to the automatic selection method, can further improve the accuracy of defect location search.

[0060] In some embodiments of the present invention, an ultrasonic non-destructive scanning device is used for ultrasonic scanning, and the ultrasonic non-destructive scanning device includes an ultrasonic probe 40 and a transfer mechanism, etc. The end of the transfer mechanism is connected to the ultrasonic probe 40, and is used to drive the ultrasonic probe 40 to scan and move. Since the distance between the ultrasonic probe 40 and the surface of the workpiece needs to be kept constant during the ultrasonic non-destructive testing scanning process, and there is high noise pollution in the scanning process, the ultrasonic probe 40 is driven to move and scan by the transfer mechanism instead of manually holding the ultrasonic probe 40 for scanning, which can better ensure the accuracy of the detection process and improve the efficiency, and is also conducive to reducing the labor intensity of workers.

[0061] In some embodiments of the present invention, step S100, performing ultrasonic scanning on the workpiece and position encoding the scanning trajectory path, further includes the following steps:

[0062] At the same time, the position data of the end of the current transfer mechanism in the transfer mechanism coordinate system is recorded and saved in one-to-one correspondence with the coded position data;

[0063] At the same time, in step 400, according to the coded position corresponding to the center of the selected image area, tracing back to the defect position actually corresponding to the workpiece, the following steps are also included:

[0064] The position in the transfer mechanism coordinate system corresponding to the encoding position corresponding to the center of the selected image area is obtained, and the end of the transfer mechanism is controlled to move to the position.

[0065] By encoding the position of the scanning trajectory path, the position data of the end of the transfer mechanism (i.e., the ultrasonic probe 40) in the coordinate system of the transfer mechanism is recorded, and then saved one by one following the encoded position data; after finding the defect position in the image and obtaining the encoded position corresponding to the defect position in the image, it is possible to ensure association and extraction, and the position of the ultrasonic probe 40 in the coordinate system of the transfer mechanism when scanning the defect position of the workpiece; then, during the backtracking process, the transfer mechanism is controlled to drive the end of the transfer mechanism to this position, and the backtracking can be completed, thereby facilitating operations such as marking or repairing the defect position of the workpiece.

[0066] Specifically, the transfer mechanism selects to use the robot 10, and the ultrasonic probe 40 is connected to the end of the robot through the end effector. The robot 10 itself can obtain the current position of the robot at any time. The current position of the robot is the coordinate position of the robot end relative to the robot coordinate system with the base of the robot 10 as the origin. At this time, the position data of the end of the transfer mechanism (that is, the ultrasonic probe 40) in the transfer mechanism coordinate system is the position of the ultrasonic probe 40 in the robot coordinate system.

[0067] Of course, according to actual conditions, in some other embodiments, the transfer mechanism may also choose to adopt other types of transfer mechanisms other than robots, as long as it can ensure that the position of the end of the transfer mechanism in the transfer mechanism's own coordinate system can be obtained at any time inside the transfer mechanism.

[0068] For smaller workpieces, the workspace of the transfer mechanism itself will be sufficient to meet the requirements of comprehensive scanning of the entire workpiece surface; however, when the workpiece to be scanned is larger, the size of the workspace of the transfer mechanism itself will be difficult to meet the scanning requirements of the workpiece.

[0069] In order to increase the size of the scanning workspace, in some embodiments of the present invention, the transfer mechanism can be slidably disposed on the ground rail.

[0070] And, specifically, in step S100, the workpiece is ultrasonically scanned, and the scanning trajectory path is position-encoded, and the following steps are also included:

[0071] At the same time, the ground rail position data where the transfer mechanism is currently located is recorded and stored in one-to-one correspondence with the coded position data.

[0072] Specifically, in step S400, according to the coded position corresponding to the center of the selected image area, tracing back to the defect position actually corresponding to the workpiece, the following steps are also included:

[0073] The ground rail position corresponding to the encoding position corresponding to the center of the selected image area is obtained, and the transfer mechanism is controlled to move to the position.

[0074] By encoding the scanning trajectory path, the position data of the end of the transfer mechanism (i.e., the ultrasonic probe 40) in the transfer mechanism coordinate system and the ground rail position data where the transfer mechanism is currently located are recorded, and then the encoded position data are saved one by one; after the defect position is found in the image and the encoded position corresponding to the defect position in the image is obtained, it is possible to ensure association and extraction of the ground rail position where the transfer mechanism is located when the ultrasonic probe 40 scans the defect position of the workpiece, and the position of the ultrasonic probe 40 in the transfer mechanism coordinate system at that time; then in the backtracking process, the transfer mechanism is first controlled to come to the corresponding ground rail position, and then the end of the transfer mechanism is controlled to come to the corresponding position in the transfer mechanism coordinate system, and the backtracking can be completed, thereby facilitating operations such as marking or repairing the defect position of the workpiece.

[0075] Specifically, refer to Figure 6The transfer mechanism uses a robot 10, an ultrasonic probe 40 is connected to the end of the robot through an end effector, the robot 10 is set on a slide 20, the slide 20 is slidably connected to a ground rail (not shown in the drawings), and a slide drive device 30 is set on the slide 20 to drive the slide 20 and the robot 10 to slide on the ground rail.

[0076] Of course, according to actual conditions, in addition to increasing the working space by sliding the transfer mechanism onto the ground rail, in some other embodiments of the present invention, it is also possible to choose to use a transfer mechanism that has a larger working space. For example, a large beam crane installed in a factory building is used to carry the ultrasonic probe 40 for mobile scanning.

[0077] In some embodiments of the present invention, due to the limited data processing capability of the ultrasonic detector, for some extra-large workpieces, if the ultrasonic probe 40 is used to complete a single scan, the image data to be generated is huge, and thus the ultrasonic detector cannot process the data. In order to solve the above problem, step S100, ultrasonic scanning of the workpiece and position encoding of the scanning trajectory path are also included in the following steps:

[0078] The workpiece is divided into several areas and numbered; the areas with different numbers are respectively subjected to ultrasonic scanning and scanning trajectory path position coding.

[0079] Specifically, by dividing the surface of the workpiece into multiple small areas of appropriate size according to the data processing capability of the ultrasonic detector itself, it is convenient to scan each area separately in the subsequent scanning. After the scanning, the scanning signal data and coded position data of each numbered area are obtained. Then, the ultrasonic detector generates an image based on the scanning signal data and coded position data of each small area. At this time, the image that needs to be generated is only the image corresponding to each small area, and there will be no problem of being unable to process due to the huge image data.

[0080] In some embodiments of the present invention, the large workpiece to be inspected may be an ordinary flat plate, or may be a curved plate, etc. To adapt to the inspection of the curved plate, step S100 performs ultrasonic scanning on the workpiece and performs position encoding on the scanning trajectory path, and also includes the following steps:

[0081] Each area of ​​the workpiece is profiled and scanned according to the surface contour of the workpiece, and each scanning position in the scanning trajectory is converted into the coordinates of the workpiece profiling plane for encoding.

[0082] Specifically, during the mobile scanning process, the ultrasonic probe 40 moves along the curved contour of the workpiece surface so that the gap between it and the workpiece surface is always kept constant, and the direction in which the ultrasonic probe 40 emits ultrasonic waves is always kept perpendicular to the workpiece surface. In addition, the coded position data generated during the position coding process is plane position data, and the plane is recorded as the workpiece profiling plane. When generating an image, the scanning signal data will generate plane image data according to the coded position data.

[0083] In some embodiments of the present invention, in step S100, especially before the ultrasonic scanning of the workpiece, the following steps are also included:

[0084] A model of the workpiece and the ultrasonic non-destructive scanning device is established, and the scanning trajectory path of the workpiece surface is planned through offline simulation.

[0085] When the workpiece is large, it is not suitable to directly perform actual scanning trajectory path planning on the workpiece surface through an ultrasonic non-destructive scanning device, so offline simulation is chosen for planning.

[0086] Specifically, firstly, a model of the workpiece and the ultrasonic scanning device is established by three-dimensional software, and then the point trajectory that the ultrasonic probe 40 in the ultrasonic scanning device needs to scan is simulated by offline simulation of the software, and then the point trajectory is exported to the controller related to the ultrasonic scanning device, that is, the scanning trajectory path of the workpiece surface is planned. In the actual scanning process, a certain reference on the workpiece is referred to, and then the scanning is performed according to the planned point trajectory.

[0087] Furthermore, if the workpiece surface is divided into small areas, a scanning trajectory path is planned for each small area so that the ultrasonic probe 40 can cover the entire small area.

[0088] Reference Figure 1 In some embodiments of the present invention, after step S400, the following steps are further included:

[0089] S500, spray marking and / or repairing the defective position of the workpiece.

[0090] Specifically, the end of the transfer mechanism is connected to a spray printer for spraying and / or a repair device for repairing defects. When the end of the transfer mechanism traces back to the defective position, the defective position is spray-marked or repaired by the spray printer and / or the repair device.

[0091] In some embodiments of the present invention, the ultrasonic non-destructive testing defect position backtracking method of the present invention is mainly used in the process of testing composite materials; and, specifically, the end of the transfer mechanism is also connected to a camera module for auxiliary detection, and the camera module is used to detect the surface material of the composite material.

[0092] Of course, according to actual conditions, in some other embodiments of the present invention, the ultrasonic non-destructive testing defect position backtracking method of the present invention can also be applied to the detection process of other types of materials, as long as the material can be penetrated by ultrasound, such as metal materials, concrete materials, etc.

[0093] Reference Figures 1 to 6 The following describes the ultrasonic nondestructive testing defect position tracing method according to an embodiment of the present invention in the form of a specific embodiment. It is worth noting that the following description is only an exemplary description and is not a specific limitation of the present invention.

[0094] Reference Figure 6 In this embodiment, an ultrasonic nondestructive testing system is used to perform ultrasonic nondestructive testing. The ultrasonic nondestructive testing system includes an ultrasonic nondestructive scanning device, a controller (not shown in the drawings), a human-computer interaction terminal (not shown in the drawings), an encoder (not shown in the drawings), an ultrasonic flaw detector (not shown in the drawings), a slide 20, a slide drive device 30 and a ground rail (not shown in the drawings). The ultrasonic non-destructive scanning device includes an ultrasonic probe 40 and a transfer mechanism. The transfer mechanism adopts a robot 10. The ultrasonic probe 40 is connected to the end of the robot. The robot 10 is arranged on a slide 20. The slide 20 can be slidably arranged on a ground rail. The slide drive device 30 is arranged on the slide 20, and is used to drive the slide 20 to move on the ground rail. The encoder is arranged on the slide 20 or the robot 10, and is used to encode the scanning trajectory path during the scanning process of the ultrasonic probe 40; the encoder and the ultrasonic probe 40 are both electrically connected to the ultrasonic flaw detector, and are respectively used to transmit the encoded position data and the scanning signal data to the ultrasonic flaw detector; the human-computer interaction terminal, the ultrasonic flaw detector and the robot 10 are all electrically connected to the controller; wherein the controller adopts a PLC, the human-computer interaction terminal adopts a PC, and the PC has human-computer interaction software installed inside, and the ultrasonic probe 40 is a phased array probe.

[0095] Reference Figures 1 to 5 The ultrasonic nondestructive testing defect position tracing method of this embodiment includes the following steps.

[0096] S100, ultrasonically scan the workpiece and position encode the scanning trajectory path to obtain scanning signal data and encoded position data.

[0097] The above step S100 includes the following three sub-steps S110, S120 and S130.

[0098] S110, dividing the workpiece into several areas and numbering them;

[0099] The entire large workpiece surface is divided into several small areas, and each small area is numbered.

[0100] Due to the limited data processing capability of ultrasonic detectors, for large workpieces, if a phased array probe is used to scan them once, the image data required to be generated is huge, so the ultrasonic detector cannot process the data. The workpiece surface is divided into multiple small areas of appropriate size according to the data processing capability of the ultrasonic detector itself, so that each area can be scanned separately in the subsequent scanning.

[0101] S120, planning a scanning trajectory path;

[0102] When the workpiece is relatively large, it is not suitable to directly perform actual scanning trajectory planning on the workpiece surface by using an ultrasonic non-destructive scanning device. In this embodiment, planning is performed in the form of off-line simulation.

[0103] Specifically, firstly, a model of the workpiece, ultrasonic nondestructive scanning device, slide 20, and ground rail is established through three-dimensional software, and then the point trajectory that needs to be scanned by the end of the robot is simulated through software offline simulation, and then the point trajectory is exported to the controller, that is, the scanning trajectory path of the workpiece surface is planned. In the actual scanning process, a certain reference on the workpiece is referred to, and then the scanning is performed according to the planned point trajectory. In addition, for each small area, a scanning trajectory path that enables the ultrasonic probe 40 to cover the entire small area is planned.

[0104] S130, performing ultrasonic scanning and scanning trajectory path position encoding on different numbered areas respectively, and generating scanning signal data and encoding position data.

[0105] During the scanning process, each area of ​​the workpiece is profiled according to the surface contour of the workpiece, and each scanning position in the scanning trajectory is converted into the coordinates of the workpiece profiling plane for encoding. During the profiling scanning process, the gap between the ultrasonic probe 40 and the workpiece surface is kept constant, and the direction of the ultrasonic probe 40 emitting ultrasonic waves is always kept perpendicular to the workpiece surface.

[0106] Specifically, the controller controls the slide drive device 30 to start, thereby driving the robot 10 to move to the specified ground rail position. At the same ground rail position, the robot 10 carrying the ultrasonic probe 40 can scan multiple different numbered areas in sequence. In each area, such as Figure 5 As shown, the robot 10 carries an ultrasonic probe 40 to perform profiling scanning on the surface of the workpiece along a continuously bent S-shaped trajectory; Figure 5 In the figure, the horizontal arrow lines in the left and right directions represent the actual scanning trajectory of the center of the ultrasonic probe 40; Figure 5 In the figure, the vertical arrow line represents the action of changing the scanning track of the center of the ultrasonic probe 40.

[0107] The following takes right as the positive direction as an example. When scanning from left to right along the horizontal arrow line, the robot 10 sends a signal to the encoder and the ultrasonic detector through the IO signal. At this time, the IO signal indicates that it is in the "scanning" state and the direction is "positive". After the ultrasonic detector receives the signal, it controls the ultrasonic probe 40 to start working, thereby scanning; when moving from top to bottom along the vertical arrow line, the robot 10 sends a signal to the encoder and the ultrasonic detector through the IO signal. At this time, the IO signal indicates the "stepping" state, which means that the robot 10 at this time is carrying the ultrasonic probe 40 to move to the next scanning track and is in a non-scanning state. After receiving the signal, the ultrasonic detector controls the ultrasonic probe 40 to end the work; after the transfer scanning track is completed, the ultrasonic probe 40 will scan along the horizontal arrow from right to left. At the beginning of the scanning, the robot 10 sends a signal to the encoder and the ultrasonic detector through the IO signal. At this time, the IO signal indicates that it is in the "scanning" state and the direction is "negative". After the ultrasonic detector receives the signal, it controls the ultrasonic probe 40 to continue to work and scan; then the ultrasonic probe 40 will continue to move along the vertical arrow line from top to bottom, and continue to send a signal indicating the "stepping" state to the encoder and the ultrasonic detector. After receiving the signal, the ultrasonic detector controls the ultrasonic probe 40 to end the work; then, the robot 10 carries the ultrasonic probe 40 and repeats the above process in sequence until all the scanning paths represented by all the horizontal arrow lines in the current entire numbered area are completed, and the scanning of the current numbered area is completed; in the process of each scanning operation of the ultrasonic probe 40, scanning signal data will be generated and transmitted to the ultrasonic flaw detector. Among them, partial overlap is allowed between the scanning areas of the ultrasonic probe 40 corresponding to two adjacent scanning tracks to ensure that all positions in the coding area can be scanned to avoid omissions.

[0108] In the process of sending a signal indicating the "scanning" state to the encoder through the IO signal until sending a signal indicating the "stepping" state to the encoder through the IO signal, the current position of the robot is sent to the encoder in real time. The current position of the robot is the position of the robot end (ultrasonic probe 40) in the robot coordinate system. The encoder processes the received real-time current position of the robot and converts it into the plane coordinate of the workpiece surface profiling, that is, the encoding position. In the process of cyclically scanning the entire numbered area, the encoder will also cyclically perform the above encoding process, thereby converting the entire curved surface of the current numbered area into a plane coordinate encoding position.

[0109] While converting the current position of the robot into the coded position of the workpiece profiling plane coordinates in real time, the coding system also records the current track position of the robot 10, the current scanning area number, and the position of the current ultrasonic probe 40 in the robot coordinate system (i.e., the current position of the robot); and the coded position data of the workpiece profiling plane coordinates correspond one-to-one with the above three data and are maintained in the database.

[0110] Furthermore, when saving data, for each numbered area, when the robot 10 carries the ultrasonic probe 40 and starts scanning, a file name is generated, and the file name corresponds to the number of the area. After the robot 10 has scanned all the areas, the file names corresponding to File_1, File_2, File_3, File_4, File_5... will be generated according to the area numbers, such as 1, 2, 3, 4, 5... The coding system database stores the track position of the robot 10 when scanning the area, the scanning area number, and the position of the ultrasonic probe 40 of all scanning positions in the area in the robot coordinate system for each area.

[0111] S200, generating an image according to the scanning signal data and the encoding position data;

[0112] The scanning signal data and the coding position data corresponding to each numbered area are combined to form an image corresponding to each numbered area. Specifically, the encoder sends the coding position data to the ultrasonic detector, which is internally provided with a driver and can read the coding position data in the coding database. The ultrasonic detector images the scanning signal data of the corresponding numbered area on the plane coordinates according to the coding position data of each numbered area, thereby forming plane image data for display on the display screen of the PC and the ultrasonic flaw detector itself. In addition, specifically, the data file read by the ultrasonic detector can be switched by a button set on the ultrasonic detector or the PC, so that image displays are formed for different numbered areas respectively. In addition, with the help of the human-computer interaction software inside the PC, it is also possible to obtain multiple data files at one time, and use the dedicated driver for ultrasonic flaw detection to convert the above two types of data into images and display them on the screen of the PC, so that multiple groups of data are batched for operators to view at the same time, thereby improving the efficiency of viewing.

[0113] S300, finding and selecting a defect position on the image, and obtaining a coding position corresponding to the center of the selected image area;

[0114] In this embodiment, the above step S300 has three modes for selection, namely, manual selection step S310, automatic selection step S320, and automatic selection followed by manual selection S330. Step S310, step S320, and step S330 are described below.

[0115] S310, manually finding and selecting a defect position in the image, and obtaining a coding position corresponding to the center of the selected image area;

[0116] Specifically, the image is displayed on the screen, the operator interprets the image, draws a frame at the position where the defect exists in the image, and then obtains the coded position according to the image center corresponding to the drawn frame, that is, obtains the coded position of the workpiece profiling plane coordinate. And, specifically, the mouse is used to draw a frame at the position where the defect exists in the image, the frame is a rectangular frame, and the defect position is located within the rectangular frame.

[0117] S320, automatically finding and selecting a defect position in the image, and obtaining a coding position corresponding to the center of the selected image area;

[0118] Automatic selection is achieved through a software program preset in the ultrasonic flaw detector; first, a numerical value of a defect image area is preset; then the image is segmented by color and / or threshold value, so as to extract a color area different from a non-defective area. Since the color of the defect position in the image is obviously different from that of the non-defective area, the extracted color area will correspond to the defective area; the area of ​​the extracted color area is compared with the numerical value of the preset defect image area, and if it exceeds, an external graphic fitting is performed on the extracted color area to complete the selection; then the coding position is obtained according to the image center corresponding to the fitted external graphic, that is, the coding position of the workpiece profiling plane coordinates is obtained.

[0119] Specifically, the image is segmented by color and / or threshold, so as to extract the color area different from the defect-free area. The following method can be used: using the image space, by setting the hue, saturation and brightness values, the image is converted into a black and white picture, and then according to the converted black and white picture, the threshold is set to extract the bright area in the picture. At this time, the extracted bright area is the corresponding defect area. Among them, the image space is selected to use the HSL image space.

[0120] And, specifically, the following method can be used to perform external graphics fitting on the extracted color area: find the maximum and minimum values ​​of X and Y in all pixels of the selected bright area, and form a rectangular frame with the maximum and minimum values ​​of X and Y as the boundaries, thereby completing the selection.

[0121] S330, automatically and then manually find and select the defect position in the image, and obtain the coding position corresponding to the center of the selected image area;

[0122] In this method, the step of "automatically finding and selecting the defect position in the image" in the above S320 is first performed; if the area of ​​the extracted color region exceeds the preset value of the defect image area, the subsequent steps are the same as the above S320 step; if the area of ​​the extracted color region does not exceed the preset value of the defect image area, the above S310 step of "manually finding and selecting the defect position in the image" is performed again.

[0123] By combining automatic and manual methods, using manual methods as a supplement to automatic methods, the accuracy of defect location detection can be further improved.

[0124] S400, tracing back to the defect position actually corresponding to the workpiece according to the coded position of the center of the selected image area.

[0125] According to the coded position obtained in step S300, that is, according to the coded position of the workpiece profiling plane coordinates obtained, the ground rail position data corresponding to the robot 10 and the position data of the robot end (ultrasonic probe 40) in the robot coordinate system are obtained when the ultrasonic probe 40 passes through the actual defect position during scanning; the above two data are sent to the controller, and the controller controls the robot 10 to move to the corresponding ground rail position and the robot end to move to the corresponding position in the robot coordinate system according to the above two data, thereby realizing the backtracking of the defect position.

[0126] S500, spray marking and / or repairing the defective position;

[0127] Specifically, the end of the robot is connected to an inkjet printer for spraying and / or a repair device for repairing defects. When the end of the robot traces back to the defective position, the defective position is spray-marked and / or repaired through the inkjet printer and / or the repair device.

[0128] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0129] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. Ultrasonic nondestructive testing defect location tracing method, applied to large workpieces, characterized by: An ultrasonic non-destructive scanning device is used for ultrasonic scanning. The ultrasonic non-destructive scanning device includes an ultrasonic probe and a transfer mechanism. The end of the transfer mechanism is connected to the ultrasonic probe and is used to drive the ultrasonic probe to scan and move. The ultrasonic nondestructive testing defect position tracing method comprises the following steps: ultrasonically scanning the workpiece, and position-encoding the scanning trajectory path to obtain scanning signal data and coded position data, and recording the position data of the end of the current transfer mechanism in the transfer mechanism coordinate system, and saving it in one-to-one correspondence with the coded position data; generating an image according to the scanning signal data and the coded position data; after completing the scanning of the workpiece, then finding and selecting the defect position on the image, and obtaining the coded position corresponding to the center of the selected image area; tracing back to the defect position actually corresponding to the workpiece according to the coded position corresponding to the center of the selected image area; wherein, The method of tracing back to the actual defect position of the workpiece according to the coded position corresponding to the center of the selected image area includes the following steps: obtaining the position in the transfer mechanism coordinate system corresponding to the coded position corresponding to the center of the selected image area, and controlling the end of the transfer mechanism to move to the position.

2. The ultrasonic nondestructive testing defect position tracing method according to claim 1 is characterized in that: Finding the defect location in the image and selecting it includes the following steps: The image is displayed on the screen, and the operator interprets the image and draws a frame around the location of the defect in the image for selection.

3. The ultrasonic nondestructive testing defect position tracing method according to claim 1 is characterized in that: Finding the defect location in the image and selecting it includes the following steps: Preset defect image area; Extracting the color region that is different from the defect-free region by color and / or threshold segmentation; It is determined whether the area of ​​the extracted color region exceeds the preset defect image area. If it exceeds, an external graphic fitting is performed on the segmented color region to form a frame for frame selection.

4. The ultrasonic nondestructive testing defect position tracing method according to claim 3 is characterized in that: When the area of ​​the extracted color region does not exceed the preset defect image area, the operator interprets the image on the screen and draws a frame at the location where the defect exists in the image for selection.

5. The ultrasonic nondestructive testing defect position tracing method according to claim 3 is characterized in that: The color region distinguished from the defect-free region is extracted by color and / or threshold segmentation, including the following steps: Use image space to convert the image into black and white by setting the hue, saturation, and brightness values; According to the converted black and white image, a threshold is set to extract the bright area in the image.

6. The ultrasonic nondestructive testing defect position tracing method according to claim 5, characterized in that: Performing external graphic fitting on the extracted color area to form a frame includes the following steps: Find the maximum and minimum values ​​of X and Y in all pixels in the bright area, and use the maximum and minimum values ​​of X and Y as the boundaries of the rectangle.

7. The ultrasonic nondestructive testing defect position tracing method according to any one of claims 1 to 6, characterized in that: The transfer mechanism is slidably arranged on the ground rail; Performing ultrasonic scanning on the workpiece and encoding the scanning trajectory path also includes the following steps: recording the current ground rail position data of the transfer mechanism and saving it in one-to-one correspondence with the encoded position data; According to the coded position corresponding to the center of the selected image area, tracing back to the actual corresponding defect position of the workpiece includes the following steps: obtaining the ground rail position corresponding to the coded position corresponding to the center of the selected image area, and controlling the transfer mechanism to move to the position.

8. The ultrasonic nondestructive testing defect position tracing method according to any one of claims 1 to 6, characterized in that: Performing ultrasonic scanning on a workpiece and position encoding the scanning trajectory path includes the following steps: Divide the workpiece into several areas and number them; Ultrasonic scanning and scanning trajectory path position encoding are performed on areas with different numbers respectively.

9. The ultrasonic nondestructive testing defect position tracing method according to claim 8, characterized in that: The workpiece is ultrasonically scanned and the scanning trajectory path is position-encoded, and the following steps are also included: Each area of ​​the workpiece is profiled and scanned according to the surface contour of the workpiece, and each scanning position in the scanning trajectory is converted into the coordinates of the workpiece profiling plane for encoding.

10. The ultrasonic nondestructive testing defect position tracing method according to any one of claims 1 to 6, characterized in that: After tracing back to the actual defect location of the workpiece, the following steps are also included: Spray marking and / or repairing of defective parts of workpieces.

11. The ultrasonic nondestructive testing defect position tracing method according to any one of claims 1 to 6, characterized in that: The following steps are also included: A model of the workpiece and the ultrasonic non-destructive scanning device is established, and the scanning trajectory path of the workpiece surface is planned through offline simulation.

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