Device and method for measuring surface defects of nuclear power plant equipment

Abstract

The invention discloses a nuclear power plant equipment surface defect measuring device and method. The nuclear power plant equipment surface defect measuring device comprises a support mechanism, a multi-degree-of-freedom mechanical arm arranged on the support mechanism and a 3D image collecting mechanism arranged at the tail end of the multi-degree-of-freedom mechanical arm. The support mechanism is used for supporting the multi-degree-of-freedom mechanical arm and feeding the multi-degree-of-freedom mechanical arm into or out of a container. The multi-degree-of-freedom mechanical arm carries the 3D image acquisition mechanism to a specified position in a container through self movement; the 3D image acquisition mechanism is used for acquiring three-dimensional structured light data of surface defects at a specified position according to a monocular structured light detection principle, and generating a point cloud 3D model for size measurement. According to the invention, the carried 3D image acquisition mechanism is brought to a specified position in the container through the multi-degree-of-freedom mechanical arm, and the 3D image acquisition mechanism is used for carrying out three-dimensional scanning measurement on the specified position to obtain the size data of the defect, so that the accurate measurement of the size of the defect is realized.

Description

Technical Field

[0001] The invention relates to the technical field of non-destructive measurement of nuclear power plant equipment, and in particular to a device and method for measuring surface defects of nuclear power plant equipment. Background Art

[0002] The lower head of the water chamber of the steam generator of a nuclear power plant is a key component that withstands high pressure in the primary circuit and is usually hemispherical. Since the lower head of the water chamber is in direct contact with the high-pressure coolant from the reactor, the stress state is complex. Its inner surface is welded with 5-6mm thick stainless steel, which has good resistance to stress corrosion. During operation, the stainless steel cladding layer on the inner surface of the water chamber may be damaged due to the impact of possible foreign objects carried by the coolant, which brings great safety hazards. At present, in order to understand the internal conditions of the water chamber, power plants at home and abroad usually conduct quality inspections on the inside of the water chamber by video inspection. This inspection method can effectively detect the surface condition of the inside of the water chamber, but it cannot achieve accurate quantitative measurement of defects such as pits. At the same time, the radiation dose in the area where the steam generator water chamber is located is high, and it is difficult for staff to go to the water chamber for manual measurement. Therefore, it is urgent to use automated equipment to complete the quantitative measurement of the size of the inner surface defects and regularly track the changes in defects.

[0003] The existing technology for measuring the size of internal defects in steam generators mainly uses manual direct measurement or modeling to enter the steam generator water chamber to measure or model the defects and estimate the defect size information. This method is suitable for macroscopic measurement of single or a few obvious defects at specific locations in the water chamber. The size measurement accuracy is not high and the radiation safety risk is high. It is not suitable for accurate measurement of multiple and multiple subtle defects on the surface of the steam generator water chamber. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a device and method for measuring surface defects of nuclear power plant equipment for realizing accurate defect measurement.

[0005] The technical solution adopted by the present invention to solve the technical problem is: to provide a surface defect measuring device for nuclear power plant equipment, which is used to measure the defects on the inner surface of a container. The surface defect measuring device for nuclear power plant equipment includes a support mechanism, a multi-degree-of-freedom mechanical arm arranged on the support mechanism, and a 3D image acquisition mechanism arranged on the end of the multi-degree-of-freedom mechanical arm;

[0006] The support mechanism is used to support and send the multi-degree-of-freedom robotic arm into or out of the container; the multi-degree-of-freedom robotic arm brings the 3D image acquisition mechanism to a specified position in the container through its own movement; the 3D image acquisition mechanism obtains three-dimensional structured light data of surface defects at a specified position through the principle of monocular structured light detection, and generates a point cloud 3D model for size measurement.

[0007] In some embodiments, the 3D image acquisition mechanism includes a structured light emission module and a full-color high-definition image sensor. The structured light emission module is used to emit a planar array structured light to the surface of a specified position, and the full-color high-definition image sensor receives the structured light signal reflected by the surface of the specified position, generates a point cloud image and stores it.

[0008] In some embodiments, the nuclear power plant equipment surface defect measuring device further includes a connecting terminal, and the 3D image acquisition mechanism is connected to the end of the multi-degree-of-freedom robotic arm via the connecting terminal.

[0009] In some embodiments, the support mechanism includes a support rod, and a support connected to the support rod and rotatable relative to the support rod;

[0010] The multi-degree-of-freedom mechanical arm is connected to an end of the support away from the support rod.

[0011] In some embodiments, the support mechanism further includes a fixing flange, a slide seat and at least one slide rail;

[0012] The fixed flange is connected to the end of the slide rail and is used to cooperate with the manhole flange at the manhole of the container; the support rod is connected to the slide seat, and the slide seat is sleeved on the slide rail and can move back and forth along the axial direction of the slide rail, driving the multi-degree-of-freedom robotic arm to move.

[0013] In some embodiments, the multi-degree-of-freedom robotic arm is a six-axis robotic arm, which includes a first robotic arm, a second robotic arm, a third robotic arm, a fourth robotic arm, a fifth robotic arm and a sixth robotic arm connected in sequence by a rotating axis, the first robotic arm is connected to the support mechanism; the fourth robotic arm is arc-shaped and connected between the third robotic arm and the fifth robotic arm.

[0014] In some embodiments, the nuclear power plant equipment surface defect measuring device also includes a data processing and motion control terminal connected to the multi-degree-of-freedom robotic arm and the 3D image acquisition mechanism.

[0015] The present invention also provides a method for measuring surface defects of nuclear power plant equipment, using any of the above-mentioned nuclear power plant equipment surface defect measuring devices, the method for measuring surface defects of nuclear power plant equipment comprising the following steps:

[0016] S1. After positioning the nuclear power plant equipment surface defect measuring device at the manhole of the container, push the multi-degree-of-freedom mechanical arm of the nuclear power plant equipment surface defect measuring device into the container;

[0017] S2, controlling the multi-degree-of-freedom robotic arm to move so as to bring the 3D image acquisition mechanism thereon to a specified position in the container;

[0018] S3. The 3D image acquisition mechanism acquires three-dimensional structured light data of defects on the surface of a specified position, generates a point cloud 3D model through the acquired three-dimensional structured light data, and then performs size measurement.

[0019] In some embodiments, in step S2, the projection of the coordinate origin of the multi-degree-of-freedom robotic arm is controlled to be on the Y-axis of the container.

[0020] In some embodiments, in step S2, the distance between the 3D image acquisition mechanism and the surface of the designated position is controlled to be an effective measurement distance, and the effective measurement distance is 300 mm to 1100 mm.

[0021] The beneficial effects of the present invention are as follows: the 3D image acquisition mechanism carried by the multi-degree-of-freedom robotic arm is brought to the specified position in the container, and the 3D image acquisition mechanism is used to perform three-dimensional scanning and measurement on the specified position to obtain the size data of the defect, and the measurement accuracy can reach within ±0.5mm, thereby achieving accurate measurement of the defect size; the present invention can operate stably for a long time in a high-radiation environment, replacing manual measurement, reducing the radiation dose of personnel, and improving safety.

[0022] The present invention is suitable for non-contact high-precision quantitative measurement of defects such as pits on the inner surface of a steam generator water chamber, and is convenient for regularly tracking the size changes of pit defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0024] Figure 1 It is a schematic structural diagram of a surface defect measuring device for nuclear power plant equipment according to an embodiment of the present invention;

[0025] Figure 2 It is a structural schematic diagram of a 3D image acquisition mechanism in a surface defect measurement device for nuclear power plant equipment according to an embodiment of the present invention;

[0026] Figure 3 It is a usage status diagram of a surface defect measuring device for nuclear power plant equipment according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0028] The surface defect measuring device of nuclear power plant equipment of the present invention is used to measure defects such as pits on the inner surface of a container to obtain accurate measurement results. The nuclear power plant equipment includes but is not limited to a steam generator, and the container includes a water chamber of the steam generator.

[0029] refer to Figure 1 and Figure 3A surface defect measuring device for nuclear power plant equipment according to an embodiment of the present invention may include a support mechanism, a multi-degree-of-freedom robotic arm 20 disposed on the support mechanism, a 3D image acquisition mechanism 30 disposed at the end of the multi-degree-of-freedom robotic arm 20, and a data processing and motion control terminal 40.

[0030] Among them, the support mechanism is used to support the multi-degree-of-freedom robot arm 20, and send the multi-degree-of-freedom robot arm 20 into or out of the container 100 through the manhole 101. The multi-degree-of-freedom robot arm 20 brings the 3D image acquisition mechanism 30 to the specified position in the container 100 through its own movement. The 3D image acquisition mechanism 30 is used to perform three-dimensional scanning and measurement on the surface of the specified position, and obtain the three-dimensional structured light data of defects such as pits on the surface of the specified position through the principle of monocular structured light detection, and generate a point cloud 3D model for size measurement. The data processing and motion control terminal 40 is connected to the multi-degree-of-freedom robot arm 20 to control the opening and closing and motion posture of the multi-degree-of-freedom robot arm 20; the data processing and motion control terminal 40 is connected to the 3D image acquisition mechanism 30 to control the opening and closing of the 3D image acquisition mechanism 30 and receive, process and store the data transmitted by the 3D image acquisition mechanism 30, and can automatically or semi-automatically extract data feature points and reconstruct the high-quality three-dimensional form of the specified surface defects.

[0031] In some embodiments, the support mechanism may include a support rod 11 and a support 12 connected to the support rod 11, and the multi-degree-of-freedom robot 20 is connected to one end of the support 12 away from the support rod 11. The support 12 can rotate relative to the support rod 11 so that the support 12 can be converted between a first state and a second state. In the first state, the support 12 is axially connected to the support rod 11, and the two can be on the same straight line, so that it is convenient to push the multi-degree-of-freedom robot 20 on the support 12 from a straight direction (axially) into the container 100. In the second state, the support 12 has a predetermined angle of inclination relative to the first state, that is, it is connected at an angle with the support rod 11, so that the projection of the coordinate origin of the multi-degree-of-freedom robot 20 (usually on the fixed base of the multi-degree-of-freedom robot 20) is on the Y axis of the container 100, which is convenient for positioning in the container 100.

[0032] When the support mechanism is in use, the support rod 11 and the support 12 extend into the container 100 in a vertical state parallel to the center line of the manhole 101 on the container, driving the multi-degree-of-freedom robot 20 thereon to enter the container 100. In the container 100, the support 12 is then rotated relative to the support rod 11 by a predetermined angle, so that the projection of the coordinate origin of the multi-degree-of-freedom robot 20 is on the Y axis of the container 100.

[0033] Furthermore, the support mechanism may also include a fixed flange (not shown), a slide seat 13, and at least one slide rail 14. The slide rail 14 corresponds to the outside of the container 100, and the fixed flange is connected to the end of the slide rail 14, and is used to cooperate with the manhole flange at the manhole 101 of the container 100 to lock the support mechanism at the manhole 101. The fixed flange can be locked at one side of the manhole flange at the manhole by nylon bolts, and a nylon gasket is provided between the fixed flange and the manhole flange for protection.

[0034] The slide 13 is sleeved on the slide rail 14 and can move back and forth along the axial direction of the slide rail 14. The support rod 11 is connected to the slide 13 and can move back and forth along the axial direction of the slide rail 14 with the slide 13, driving the multi-degree-of-freedom robot 20 to move back and forth along the slide rail 14. The back and forth movement of the slide 13 on the slide rail 14 can be achieved by a driving mechanism such as a cylinder.

[0035] There are preferably two or more slide rails 14 so that the slide seat 13 and the support rod 11 can be moved and positioned on the slide rails 14 in a balanced and stable manner.

[0036] In order to achieve lightweight and easy installation of the bracket mechanism, the bracket mechanism is mainly made of carbon fiber and lightweight aluminum alloy. For example, the slide rail 14, the fixing flange and the slide seat 13 are respectively made of lightweight aluminum alloy, the support rod 11 and the support seat 12 are respectively supported by carbon fiber, etc. The bracket mechanism terminal carries a load of no less than 3kg.

[0037] The fixed base 201 of the multi-degree-of-freedom robot 20 can be connected to the end of the support 12 through a quick connector, so as to realize a reliable connection of the multi-degree-of-freedom robot 20 on the bracket mechanism to form a whole.

[0038] In some embodiments, Figure 1 As shown, the multi-degree-of-freedom robot 20 is a six-axis robot. The six-axis robot includes a first robot 21, a second robot 22, a third robot 23, a fourth robot 24, a fifth robot 25, and a sixth robot 26 connected in sequence through a rotation axis; the six-axis robot is connected to the support mechanism with its first robot 21, and the 3D image acquisition mechanism 30 is mounted on the sixth robot 26.

[0039] Preferably, in order to ensure that the mechanical arms do not block each other during movement, do not generate inspection blind spots due to their own structures, and ensure full coverage of the interior of the container, the fourth mechanical arm 24 has an arc, so that the fourth mechanical arm 24 is curved and connected between the third mechanical arm 23 and the fifth mechanical arm 25. In addition, the arc-shaped bending setting of the fourth mechanical arm 24 also enables the 3D image acquisition mechanism 30 to be coaxial with the support mechanism and smoothly pass through the manhole 101 to enter and exit the container 100 when the six-axis mechanical arm carries the 3D image acquisition mechanism 30 through the manhole 101 to enter and exit the container 100.

[0040] The working radius of the multi-degree-of-freedom robot arm 20 is not less than 850 mm, which provides a suitable measurement distance for the 3D image acquisition mechanism 30 and can improve the measurement accuracy.

[0041] The 3D image acquisition mechanism 30 is preferably connected to the end of the multi-degree-of-freedom robot arm 20 via a connection terminal 50 . The connection wire of the 3D image acquisition mechanism 30 can be connected to the data processing and motion control terminal 40 via an interface on the connection terminal 50 .

[0042] The connection terminal 50 is also used to realize a quick connection between the 3D image acquisition mechanism 30 and the end of the multi-degree-of-freedom robotic arm 20, so as to facilitate disassembly, assembly, replacement, etc.

[0043] refer to Figure 2 In some embodiments, the 3D image acquisition mechanism 30 includes a structured light emission module 31 and a full-color high-definition image sensor 32. The structured light emission module 31 is used to emit a planar array structured light to the surface of a specified position, and the full-color high-definition image sensor 32 receives the structured light signal reflected by the surface of the specified position, generates a point cloud image and stores it.

[0044] The 3D image acquisition mechanism 30 may further include an Ethernet interface and a power interface, and the Ethernet interface and the power interface are respectively connected to the data processing and motion control terminal 40 through connecting wires.

[0045] The 3D image acquisition mechanism 30 can output data in various formats, process the data through corresponding data analysis software, generate a high-quality 3D model, and realize functions such as dimension measurement based on the 3D model. The data analysis software can be integrated in the data processing and motion control terminal 40.

[0046] Combination Figures 1 to 3 The method for measuring surface defects of nuclear power plant equipment implemented by the nuclear power plant equipment surface defect measuring device of the present invention may include the following steps:

[0047] S1. After positioning the nuclear power plant equipment surface defect measuring device at the manhole 101 of the container 100, the multi-degree-of-freedom robot arm 20 of the nuclear power plant equipment surface defect measuring device is pushed into the container 100.

[0048] Specifically, outside the container 100, the multi-degree-of-freedom robot 20 can be folded on the support rod 11 and the support 12 of the support mechanism so that the three are coaxial. The fixing flange is locked on the manhole flange at the manhole 101. At this time, the support mechanism and the multi-degree-of-freedom robot 20 thereon are all outside the manhole 101.

[0049] The support rod 11 , the support 12 and the multi-degree-of-freedom robot arm 20 are pushed into the container 100 by the movement of the slide 13 on the slide rail 14 .

[0050] S2 . Control the multi-degree-of-freedom robot arm 20 to move so as to bring the 3D image acquisition mechanism 30 thereon to a designated position in the container 100 .

[0051] Specifically, the support 12 can be moved relative to the support rod 11 to a predetermined inclination angle (for example, 30°) by operating the data processing and motion control terminal 40. Figure 1 The state shown in FIG. 1 is thus controlled so that the projection of the coordinate origin of the multi-degree-of-freedom robot arm 20 is on the Y axis of the container 100, as shown in FIG. Figure 3 As shown (only X and Z axes are marked in the figure) for easy positioning.

[0052] By operating on the data processing and motion control terminal 40, each arm of the multi-degree-of-freedom robot 20 is controlled to move according to the set motion trajectory, so as to bring the 3D image acquisition mechanism 30 on the end to the specified position in the container 100, and at the same time control the distance and angle between the 3D image acquisition mechanism 30 and the surface of the specified position, control the distance within the effective measurement distance and ensure that the specified position is within the acquisition range of the 3D image acquisition mechanism 30, so as to ensure that the focus of the 3D image acquisition mechanism 30 can be aligned with the specified position for acquisition.

[0053] In some embodiments, the effective measurement distance is 300 mm to 1100 mm, preferably 400 mm to 900 mm.

[0054] S3. The 3D image acquisition mechanism 30 acquires three-dimensional structured light data of defects such as pits on the surface of a specified position, generates a point cloud 3D model through the acquired three-dimensional structured light data, and then performs dimensional measurement.

[0055] The structured light transmitting module 31 is used to emit planar array structured light to the surface of the designated position, and the full-color high-definition image sensor 32 receives the structured light signal reflected by the surface of the designated position to generate a point cloud image.

[0056] The three-dimensional structured light data collected by the 3D image acquisition mechanism 30 can be processed and stored by corresponding data analysis software to generate a point cloud 3D model for dimensional measurement, thereby obtaining the dimensional data of the defect with high measurement accuracy.

[0057] Furthermore, in the device and / or method of the present invention, an artificial flaw test block may be provided to simulate the defect morphology of the inner surface of the container 100, so as to verify the measurement accuracy of the 3D image acquisition mechanism 30. The artificial flaw test block is formed by a stainless steel plate and a plurality of flat-bottom holes provided thereon, and the plurality of flat-bottom holes have different depths.

[0058] Take the container 100 as a steam generator water chamber as an example:

[0059] The lower head of the steam generator is a hemispherical container with the upper part welded to the tube sheet. The lower head is divided into two water chambers by a partition plate. Each water chamber has a connecting pipe connected to the reactor pressure vessel and a manhole. The inside of the water chamber is a high radiation dose area.

[0060] With reference to the above method, the present invention uses a multi-degree-of-freedom robotic arm 20 equipped with a 3D image acquisition mechanism 30 to perform three-dimensional scanning measurement of a designated position in a water chamber through the coordinated work of various components of the surface defect measurement device for nuclear power plant equipment. The measurement accuracy can reach within ±0.5mm, thereby achieving accurate measurement of the pit defect size.

[0061] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A surface defect measuring device for nuclear power plant equipment, characterized in that: Used to measure defects on the inner surface of a container, the surface defect measuring device for nuclear power plant equipment includes a support mechanism, a multi-degree-of-freedom mechanical arm arranged on the support mechanism, and a 3D image acquisition mechanism arranged on the end of the multi-degree-of-freedom mechanical arm; The support mechanism is used to support and send the multi-degree-of-freedom robotic arm into or out of the container; The multi-degree-of-freedom robotic arm brings the 3D image acquisition mechanism to a specified position in the container through its own movement; the 3D image acquisition mechanism obtains three-dimensional structured light data of surface defects at the specified position through the principle of monocular structured light detection, and generates a point cloud 3D model for size measurement.

2. The surface defect measuring device for nuclear power plant equipment according to claim 1, characterized in that: The 3D image acquisition mechanism includes a structured light emission module and a full-color high-definition image sensor. The structured light emission module is used to emit a planar array structured light to the surface of a specified position, and the full-color high-definition image sensor receives the structured light signal reflected by the surface of the specified position, generates a point cloud image and stores it.

3. The surface defect measuring device for nuclear power plant equipment according to claim 2, characterized in that: The nuclear power plant equipment surface defect measuring device also includes a connecting terminal, and the 3D image acquisition mechanism is connected to the end of the multi-degree-of-freedom mechanical arm through the connecting terminal.

4. The surface defect measuring device for nuclear power plant equipment according to claim 1, characterized in that: The support mechanism includes a support rod and a support seat connected to the support rod and rotatable relative to the support rod; The multi-degree-of-freedom mechanical arm is connected to an end of the support away from the support rod.

5. The surface defect measuring device for nuclear power plant equipment according to claim 4, characterized in that: The support mechanism also includes a fixing flange, a sliding seat and at least one sliding rail; The fixed flange is connected to the end of the slide rail and is used to cooperate with the manhole flange at the manhole of the container; the support rod is connected to the slide seat, and the slide seat is sleeved on the slide rail and can move back and forth along the axial direction of the slide rail, driving the multi-degree-of-freedom robotic arm to move.

6. The nuclear power plant equipment surface defect measuring device according to any one of claims 1 to 5, characterized in that: The multi-degree-of-freedom robotic arm is a six-axis robotic arm, which includes a first robotic arm, a second robotic arm, a third robotic arm, a fourth robotic arm, a fifth robotic arm and a sixth robotic arm which are connected in sequence by a rotating axis, wherein the first robotic arm is connected to the support mechanism; the fourth robotic arm is connected between the third robotic arm and the fifth robotic arm in an arc shape.

7. The nuclear power plant equipment surface defect measuring device according to any one of claims 1 to 5, characterized in that: The nuclear power plant equipment surface defect measuring device also includes a data processing and motion control terminal connected to the multi-degree-of-freedom mechanical arm and the 3D image acquisition mechanism.

8. A method for measuring surface defects of nuclear power plant equipment, characterized in that: The nuclear power plant equipment surface defect measuring device according to any one of claims 1 to 6 is used, and the nuclear power plant equipment surface defect measuring method comprises the following steps: S1. After positioning the nuclear power plant equipment surface defect measuring device at the manhole of the container, push the multi-degree-of-freedom mechanical arm of the nuclear power plant equipment surface defect measuring device into the container; S2, controlling the multi-degree-of-freedom robotic arm to move so as to bring the 3D image acquisition mechanism thereon to a specified position in the container; S3. The 3D image acquisition mechanism acquires three-dimensional structured light data of defects on the surface of a specified position, generates a point cloud 3D model through the acquired three-dimensional structured light data, and then performs size measurement.

9. The method for measuring surface defects of nuclear power plant equipment according to claim 8, characterized in that: In step S2, the projection of the coordinate origin of the multi-degree-of-freedom robotic arm is controlled to be on the Y-axis of the container.

10. The method for measuring surface defects of nuclear power plant equipment according to claim 8, characterized in that: In step S2, the distance between the 3D image acquisition mechanism and the surface of the designated position is controlled to be an effective measurement distance, and the effective measurement distance is 300 mm to 1100 mm.

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