An adaptive scanning method and system for a nodal pipe socket

Abstract

The present application relates to a kind of self-adapting scanning method and system for nodular cast iron pipe socket, design a kind of based on robot, PLC, 2D / 3D camera, sensor, can be directed to the self-adapting scanning method and system for nodular cast iron pipe socket.Method includes the design method of robot action, adaptive robot trajectory generation method, system is based on the overall construction of appropriate hardware equipment selected based on the method.The present application solves the problem that robot teaching work is tedious in the traditional scanning method for nodular cast iron pipe socket, greatly reduces the workload of debugging and the workload of later maintenance, and the system can be reused on cast pipe production line, and simultaneously has the possibility of being popularized to similar scenarios in other industries.

Description

TECHNICAL FIELD

[0001] The application relates to a self-adaptive scanning method and system for a cast iron pipe socket, and belongs to the technical field of automation in the cast pipe industry. BACKGROUND

[0002] With the advancement of urbanization construction in China, the cast iron pipe is mainly used in underground pipe network engineering construction in the construction process, and is an ideal pipe material for urban water supply and gas transmission. For the production of the cast iron pipe, in addition to the production technology, automation, informatization and intelligentization are also the research focus in the current industry.

[0003] In the informatization construction of the cast iron pipe production line, the quality traceability of each cast pipe product in the production process is a key problem. At present, the cast pipe usually adopts the method of marking on the inner wall of the socket to identify the specification, model, production year or number and other information of each cast pipe. Therefore, how to obtain these information in the key process of production becomes a problem. The common method is still to record these information manually by the post operators, which is time-consuming and laborious. Therefore, there is a scheme of scanning by using a mechanical device or a robot in the production line with high intelligence, but this method also has problems. The flexibility and accuracy of the mechanical device are not enough, and the universality is not enough if adjustment is needed in the later period. The conventional method of using a robot has a large teaching workload in the early stage, and a large teaching workload is still needed in the later period if adjustment is needed. At the same time, when such equipment is added to the production line, the production line has been formed and put into production, and the factory will not give the debugging personnel too much debugging time. In addition, due to the rich specifications of the pipes, it is also difficult to provide all the pipe types at any time, and the work is difficult to carry out.

[0004] Therefore, the method and the system solve the problems of the above-mentioned several methods, and propose a self-adaptive scanning method, which has great practical significance. SUMMARY

[0005] The application is mainly used in the informatization construction of the cast iron pipe production line in the cast pipe industry. When the information marked on the socket is obtained, the manual scheme has low intelligence, is time-consuming and laborious, the mechanical device has low flexibility and accuracy, the conventional robot scheme has a large teaching workload, and the work is difficult to carry out. Therefore, a self-adaptive scanning method and system for the cast iron pipe socket are proposed to solve the problem.

[0006] To solve the above-mentioned problems, the technical scheme adopted by the application is as follows: a self-adaptive scanning method for a cast iron pipe socket, comprising the following steps:

[0007] A first sensor and a second sensor are arranged on the periphery of the cast pipe socket, and a teaching point is arranged;

[0008] According to the teaching point position and the information of the first sensor and the second sensor, a scanning track is generated, and the robot scans the bell mouth to realize adaptive scanning.

[0009] The first sensor and the second sensor are both ranging sensors;

[0010] The first sensor is arranged at a central position when facing the bell mouth, and the height is a set distance above the center of the bottom of the bell mouth, so that the laser point of the first sensor penetrates the pipe body, and the laser point is vertically shot into the bell mouth plane from the spigot, and is shot out from the spigot, so as to search for the edge of the pipe mouth, obtain the nearest distance from the sensor to the bell mouth of the cast pipe, and transmit the distance data to the robot, for determining the distance of the robot when scanning.

[0011] The second sensor is arranged vertically downward above the cast pipe when the cast pipe is stopped, and the height is at least higher than the diameter of the largest pipe diameter type to be detected, so as to detect the pipe diameter, and transmit the distance data to the robot for judging the pipe diameter.

[0012] The setting of the teaching point position includes reserving a teaching point, and the reserving of the teaching point includes:

[0013] The teaching points of the robot entering and exiting the bell mouth are reserved, two points are reserved when entering, and one point is reserved when exiting;

[0014] The teaching points in the scanning process of the robot are reserved, and six points are reserved in total in the scanning process.

[0015] The setting of the teaching point position includes points 1-11;

[0016] Points 1 and 11 are the original points;

[0017] Point 2 is a point before entering and scanning, and is the first point for scanning the bell mouth;

[0018] Point 3 is the first point for scanning the bell mouth after entering, and the teaching position is the same as that of point 2;

[0019] Points 4, 5, 6 and 7 are points on the scanning path of the bell mouth, and the teaching positions are the same as that of point 3, which respectively correspond to points obtained by rotating point 3 by 90 degrees, 180 degrees, 270 degrees and 360 degrees clockwise around the x-axis;

[0020] Point 8 is the last point for scanning the bell mouth, and is a point obtained by rotating point 7 by 45 degrees clockwise around the x-axis, and the teaching position is the same as that of point 7;

[0021] Point 9 is the same as point 7;

[0022] Point 10 is a point for exiting the bell mouth after completing scanning, and the teaching position is the same as that of point 9.

[0023] The process of generating a scanning trajectory based on the teaching points and information from the first and second sensors, and then having the robot scan the socket, includes the following steps:

[0024] 1) Calculate the required offsets in the y and z directions for each of the six points reserved during the scanning process, and accumulate the calculated offsets to the corresponding reserved teaching points;

[0025] 2) Based on the ranging sensor used for edge finding, the offset distance from the pipe socket to the robot is obtained. Based on this distance, the required offset in the x direction for each of the six reserved points during the scanning process is calculated, and the calculated offset is accumulated to the corresponding reserved teaching point.

[0026] The process of generating a scanning trajectory based on the teaching points and information from the first and second sensors, and then having the robot scan the socket, includes the following steps:

[0027] 1) Calculation of teaching point coordinates:

[0028] The pipe diameter offset b between point 2 and point 10 on the y and z axes is calculated and accumulated onto the original coordinate system;

[0029] 2) Offset calculation:

[0030] Calculate the x-axis offset 'a' between point 3 and point 9 and add it to the original coordinates;

[0031] 3) Deflection angle adjustment: After scanning by accumulating the pipe diameter offset b and the insertion offset a, the rotation angle of the robot on the y-axis and z-axis is adjusted by observing the imaging effect to ensure that the imaging is free from tilt and bending.

[0032] The pipe diameter offset b is obtained by (actual pipe diameter - default pipe diameter) / 2; where the default pipe diameter is the set pipe diameter, and the actual pipe diameter is the pipe diameter data obtained by the second sensor.

[0033] The specific pipe diameter offsets b along the y and z axes are as follows:

[0034] The y-axis offset of point 2 is 0, and the z-axis offset is b;

[0035] The y-axis offset of point 3 is 0, and the z-axis offset is b;

[0036] The y-axis offset of point 4 is b, and the z-axis offset is 0.

[0037] The y-axis offset of point 5 is 0, and the z-axis offset is -b;

[0038] The y-axis offset of point 6 is -b, and the z-axis offset is 0.

[0039] The y-axis offset of point 7 is 0, and the z-axis offset is b;

[0040] The y-axis offset of point 8 is a The z-axis offset is b

[0041] The y-axis offset of point 9 is 0, and the z-axis offset is b;

[0042] The y-axis offset of point 10 is 0, and the z-axis offset is b.

[0043] The extension offset a is obtained by the following steps:

[0044] The distance value m of the distance between the pipe socket end face sensor and the robot is obtained by the first sensor, the robot is extended to the socket in the x direction from point 3 and stopped at the scanning position, at this time, the x-axis offset of this position and point 3 is recorded as n; the difference between the edge searching value t measured by the first sensor and m is added to n, that is, the extension offset a.

[0045] A self-adaptive scanning system for a nodular cast iron pipe socket, comprising:

[0046] A first sensor is arranged at the center position when the socket is stopped, for determining the extension distance of the robot during scanning;

[0047] A second sensor is arranged directly above the pipe when the pipe is stopped, for judging the pipe diameter;

[0048] A trajectory generation unit is used to generate a scanning trajectory according to the teaching point position and the information of the first sensor and the second sensor;

[0049] A robot is used to scan the socket according to the scanning trajectory.

[0050] A camera is arranged at the front end of the six-axis flange of the robot, the lens is perpendicular to the x-axis of the robot, and is used for image acquisition;

[0051] A PLC is used for data communication between the sensors, the robot and the camera, and triggering of the robot action and the camera work.

[0052] The beneficial effects and advantages of the present application are:

[0053] 1. The key information of the cast pipe socket is automatically scanned, and the informationization and intelligentization level of the production line is improved.

[0054] 2. The robot trajectory is adaptively generated, and the teaching workload is reduced.

[0055] 3. The scanning trajectory of multiple pipe types is adaptively generated, which can adapt to the current unproduced models, so that the debugging work is easier to carry out.

[0056] 4、 The method and system can be popularized to other industries with similar needs, and have strong universality. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 is the overall schematic diagram of the present application.

[0058] Figure 2 is the overall flowchart of the system operation in the present application.

[0059] Figure 3 is the schematic diagram of each teaching point of the robot in the present application

[0060] Figure 4 is the flowchart of the scanning action of the robot in the present application.

[0061] Figure 5 is the flowchart of the adaptive generation of the robot trajectory in the present application.

[0062] Figure 6 is the schematic diagram of the adaptive generation of the robot trajectory in the present application. DETAILED DESCRIPTION

[0063] The present application will be described in detail below with reference to the accompanying drawings, further describing the purpose, specific technical scheme and advantages of the present application.

[0064] An adaptive scanning method and system for a ductile cast iron pipe socket, comprising the following contents:

[0065] A robot action design method, i.e. designing an action flow for the position and shape of the ductile cast iron pipe socket, reserving teaching points for the points to be generated in the adaptive trajectory generation method;

[0066] An adaptive robot trajectory generation method, including calculating the teaching point coordinates according to different pipe diameters, calculating the offset according to the distance from the socket to the robot, and adjusting the robot deflection angle according to the scanning effect;

[0067] The construction of an adaptive scanning system, i.e. based on a robot, PLC, sensor 1, sensor 2, 2D / 3D camera, satisfying the above two methods, and constructing the overall system.

[0068] The design of the action flow for the position and shape of the ductile cast iron pipe socket includes:

[0069] 1) Designing pre-scanning actions and teaching points, for adjusting the robot from the origin to the preparation posture before scanning into the socket;

[0070] 2) Designing scanning actions and teaching points, for scanning the socket;

[0071] 3) Design the post-scan action and teach point, which is used to exit the bell and return to the original attitude after the robot completes the scan;

[0072] 4) All actions meet the robot attitude accessibility and ensure the safety during the movement.

[0073] The teach point reservation for the points needed to be generated in the adaptive trajectory generation method includes:

[0074] 1) The teach points for the robot to enter and exit the bell are reserved, two points are reserved when entering, and one point is reserved when exiting;

[0075] 2) The teach points in the scanning process of the robot are reserved, a total of six points are reserved in the scanning process.

[0076] The calculation of the teach point coordinates according to different pipe diameters, the calculation of the offset according to the distance from the bell to the robot, and the adjustment of the robot deflection angle according to the scanning effect include:

[0077] 1) According to different pipe diameters, the offset in the y and z directions required by the six points reserved in the above scanning process is calculated, and the calculated offset is accumulated to the corresponding reserved teach point;

[0078] 2) Based on the ranging sensor for edge detection, the offset distance from each cast pipe bell to the robot is obtained, and the offset in the x direction required by the six points reserved in the above scanning process is calculated according to the distance, and the calculated offset is accumulated to the corresponding reserved teach point;

[0079] 3) If the image is skewed or distorted after the robot scans based on the above two calculated teach points, manual adjustment of the robot deflection angle is needed to adjust the deflection angle in the y and z axes.

[0080] The robot, PLC, sensor 1, sensor 2, 2D / 3D camera meet the above two methods, and the overall system is built, including the following contents:

[0081] 1) Robot selection and erection, a six-axis robot is selected, and the robot is placed in a suitable position that can meet the scanning attitude according to the actual situation such as the load of the robot and the arm span;

[0082] 2) Sensor erection, two ranging sensors are selected, sensor 1 is used for edge detection of the bell and is erected at a suitable distance in front of the bell, and sensor 2 is used for pipe diameter measurement and is erected at a suitable distance above the pipe body;

[0083] 3) Camera selection, according to the actual needs of 2D camera or 3D camera, both options, camera is installed in front of the robot six-axis flange, lens towards perpendicular to the robot x-axis;

[0084] 4) PLC is used for data communication between sensors, robots, cameras, and triggering of robot action and camera work.

[0085] Referring to Figure 1 This is the overall schematic diagram of the present application, as shown in the figure, the setting of each part of the system equipment, the functions contained in the method, and the overall linkage mode are described.

[0086] Pipe socket, circular, socket inside generally printed with pipe information, with ductile iron pipe production line to the scanning station.

[0087] Sensor 1 uses a range sensor, the deployment position is opposite the center position of the socket stay, the height is 5cm above the center of the pipe opening. The sensor laser point needs to penetrate the pipe body, and the laser point is perpendicular to the socket plane and enters from the socket. Its function is to find the edge of the pipe opening and obtain the nearest distance from each cast pipe socket to the sensor, and then transmit the data to the robot to determine the distance of the robot scanning.

[0088] Sensor 2 uses a range sensor, the deployment position is directly above the cast pipe, perpendicular to the highest point of the cast pipe, and the deployment height is at least 20cm higher than the diameter of the largest pipe diameter pipe type to be detected. Its function is to detect the pipe diameter, and transmit the data to the robot to determine the pipe diameter to be detected.

[0089] The robot uses a six-axis robot, which is deployed in front of the cast pipe socket, and the position needs to meet the requirements of the robot driving the camera to complete the scanning action. The functions that the robot needs to complete include reserving the teaching points when designing the robot action and generating adaptive trajectories.

[0090] PLC communicates with the robot, communicates with sensor 1 and sensor 2, and communicates with the camera. It is also used to realize the sensor edge finding logic and the sensor pipe diameter judgment logic.

[0091] The camera can be selected according to the actual needs of 2D camera or 3D camera, and is installed at the front end of the robot six-axis flange, with the lens perpendicular to the robot x-axis. The camera is driven by the robot to scan into the socket. If a 2D camera is used, multiple photos of the inner wall of the socket can be taken by shooting to ensure that all information is covered. If a 3D camera is used, a scanning image covering all information can be directly generated by scanning imaging.

[0092] Referring to Figure 2This is the overall flowchart of the system operation in this invention. First, by Figure 1 The sensor 1 shown performs real-time edge detection. The real-time edge detection logic is as follows: the sensor continuously acquires the detected distance value and transmits it to the PLC in real time. The PLC sets a socket distance range. As long as the distance value is within the range, it is considered that the edge of the pipe is passing through the sensor. At this time, the PLC always maintains a minimum distance value. If a smaller value appears, this value is updated. If 100 consecutive values ​​exceed the limit, it is considered that no socket is passing through the sensor. The purpose of this is to avoid data mutations that may occur due to unstable current and voltage. At this time, the minimum value that was just maintained is used as the final data obtained for this edge detection.

[0093] Next, we wait for the pipe arrival signal sent from the production line to the PLC. Upon receiving this signal, it is assumed that there is a pipe at the current workstation waiting to be scanned for its socket. At this time, through... Figure 1 The data acquired by sensor 2 shown in the diagram is used by the PLC to determine the pipe diameter. After the determination is completed, the PLC transmits the edge finding value and the pipe diameter value to the robot, which then generates an adaptive trajectory. Subsequently, the robot scans the socket according to the generated trajectory. After the scan is completed, the robot returns to its original position, completing one scanning process.

[0094] See Figure 3 This is a schematic diagram of the robot's teaching points in this invention. The entire motion process includes 11 teaching points, which are the positions where the robot's six axes drive the camera's movement. Points 1 and 11 are the origin; point 2 is the point before insertion and scanning, directly opposite the first point of the socket scan; point 3 is the first point of socket scanning after insertion, with the same teaching position as point 2; points 4, 5, 6, and 7 are points on the socket scanning path, with the same teaching position as point 3, corresponding to points obtained by rotating point 3 clockwise around the x-axis by 90 degrees, 180 degrees, 270 degrees, and 360 degrees respectively; point 8 is the last point of socket scanning, obtained by rotating point 7 clockwise around the x-axis by 45 degrees, with the same teaching position as point 7; point 9 is the same point as point 7; point 10 is the point where the robot exits the socket after scanning, with the same teaching position as point 9. The same teaching position means the same xyz coordinate position in space.

[0095] See Figure 4The flow chart of the robot performing the scanning action in the present application. First, the robot is at point 1 position, at this time the camera lens is directed downward, when the trigger signal for scanning is obtained, at this time the offset data is first obtained, the offset data comes from the data of sensor 1 and sensor 2, and the extension offset a and the pipe diameter offset b are calculated. Subsequently, the offset of point 2 in the z-axis direction is obtained through the pipe diameter offset b, which is added to the position of point 2, the robot moves to point 2, and the camera lens is rotated to be directed upward. The extension offset a is added to the position of point 3, the robot moves to point 3, and the camera is triggered to start working at the same time. The respective offsets in the y-axis direction and the z-axis direction of points 4, 5, 6, 7, 8, 9 on the scanning path are calculated through the pipe diameter offset b, which are added to these points, and the extension offset a is also added to these points, and then the circle scanning is performed according to these positions. The offsets in the y-axis direction and the z-axis direction calculated through the pipe diameter offset b are added to point 10, and the robot moves to point 10 after the scanning is completed, and the robot exits the socket at the same time, and the camera lens is rotated back to be directed downward. Finally, return to the original position point 1, so that a complete scanning action is completed.

[0096] Referring to Figure 5 The flow chart of the robot trajectory adaptive generation in the present application. The adaptive generation of the trajectory needs three steps in total, which are teaching point coordinate calculation, offset calculation and deflection angle adjustment. Figure 6 is a schematic view.

[0097] The teaching point coordinate calculation, that is, the offsets of points 2 to 10 in the y and z axes are added to the original coordinates (the positions of these original coordinates are all the same point), and the calculation method is as follows: the pipe diameter offset b is obtained from (actual pipe diameter-default pipe diameter) / 2, for example, the cast pipe socket with a pipe diameter of 350 is adapted in the default state, and the actual sensor 2 judges that the pipe diameter is 500, so the pipe diameter offset b is (500-350) / 2=75. The y-axis offset of point 2 is 0, and the z-axis offset is b; the y-axis offset of point 3 is 0, and the z-axis offset is b; the y-axis offset of point 4 is b, and the z-axis offset is 0; the y-axis offset of point 5 is 0, and the z-axis offset is-b; the y-axis offset of point 6 is-b, and the z-axis offset is 0; the y-axis offset of point 7 is 0, and the z-axis offset is b; the y-axis offset of point 8 is the z-axis offset is the y-axis offset of point 9 is 0, and the z-axis offset is b; the y-axis offset of point 10 is 0, and the z-axis offset is b.

[0098] The offset calculation, that is, the offset of the points 3 to 9 on the x-axis is calculated and added to the original coordinates, and the calculation method is as follows: before calculation, take a cast pipe as an example, when it moves to the work station, the distance value m of the cast pipe from the sensor is obtained through the sensor 1, at this time, the robot is manually extended from the point 3 in the x direction into the socket and stopped at a suitable scanning position, at this time, the x-axis offset of the position from the point 3 is recorded and recorded as n. Then each time the cast pipe reaches the work station, the difference between the measured edge searching value t and m is added to n, that is, the above-mentioned extension offset a.

[0099] The deflection angle adjustment, that is, after scanning through the above two offsets, the imaging effect is observed, for example, if a 2D camera is used, the photographed photo is obviously tilted, or if a 3D camera is used for scanning imaging, there is obvious bending, which indicates that the plane where the socket is located is not aligned with the actual scanning plane of the robot, and it needs to be adjusted to the same plane as much as possible, and the adjustment method is to manually fine-tune the rotation offset of the whole robot on the y-axis and the z-axis, so that the imaging has no obvious tilt and bending.

[0100] In summary, the method of the application mainly realizes the adaptive scanning of the socket of the nodular cast iron pipe, solves the problems of insufficient universality, large teaching workload and difficult debugging work in the conventional scanning method, realizes the automatic scanning of the key information of the cast pipe socket, improves the informatization and intelligent level of the production line, adaptively generates the robot track, reduces the teaching workload, and adaptively generates the scanning track of multiple pipe types, which can adapt to the current unproduced types, so that the debugging work is easier to carry out. The system constructed based on the method can also be popularized to other industries with similar needs, and has strong universality.

Claims

1. A method of adaptive scanning for a nod of a ductile cast iron pipe, characterized by, The method comprises the following steps: A first sensor and a second sensor are arranged on the periphery of the pipe socket, and a teaching point is arranged; A scanning track is generated according to the teaching point and information of the first sensor and the second sensor, and the robot scans the socket to realize adaptive scanning; The first sensor and the second sensor are both ranging sensors; The first sensor is arranged at the center position of the socket when it is directly opposite the socket, and the height is a set distance above the center of the bottom of the socket, so that the laser point of the first sensor penetrates the pipe body, and the laser point is vertically injected into the socket plane and is injected out of the socket, so as to search for the edge of the socket, obtain the nearest distance from the socket to the sensor, and transmit the distance data to the robot, which is used to determine the distance of the robot when scanning; The second sensor is arranged vertically downward above the socket when the socket is directly opposite the highest point of the socket, and the height is at least higher than the diameter of the largest pipe diameter pipe type to be detected, so as to detect the pipe diameter, and transmit the distance data to the robot for judging the pipe diameter.

2. The self-adaptive scanning method for a pipe socket of ductile cast iron pipe according to claim 1, characterized in that, The teaching point is reserved, and the teaching point reservation comprises: The teaching points of the robot entering and exiting the socket are reserved, two points are reserved when entering, and one point is reserved when exiting; The teaching points in the scanning process of the robot are reserved, and a total of six points are reserved in the scanning process.

3. The self-adaptive scanning method for a pipe socket of ductile cast iron according to claim 1 or 2, characterized in that, The teaching point arrangement comprises points 1 to 11; Points 1 and 11 are the original points; Point 2 is a point before entering and scanning, which is the first point directly opposite the socket for scanning; Point 3 is the first point for scanning the socket after entering, and the teaching position is the same as that of point 2; Points 4, 5, 6 and 7 are points on the scanning path of the socket, and the teaching positions are the same as that of point 3, which respectively correspond to points obtained by rotating point 3 by 90 degrees, 180 degrees, 270 degrees and 360 degrees clockwise around the x-axis; Point 8 is the last point for scanning the socket, which is obtained by rotating point 7 by 45 degrees clockwise around the x-axis, and the teaching position is the same as that of point 7; Point 9 is the same as point 7; Point 10 is a point for exiting the socket after completing scanning, and the teaching position is the same as that of point 9.

4. The self-adaptive scanning method for a pipe socket of ductile cast iron pipe according to claim 1, characterized in that, The scanning track is generated according to the teaching point and information of the first sensor and the second sensor, and the robot scans the socket, which comprises the following steps: 1) The offset amounts of y and z directions required by the six points reserved in the scanning process are calculated, and the calculated offset amounts are accumulated to the corresponding reserved teaching points; 2) The offset distance from the socket to the robot is obtained based on the ranging sensor for edge searching, and the offset amount of x direction required by the six points reserved in the scanning process is calculated, and the calculated offset amount is accumulated to the corresponding reserved teaching points.

5. The self-adaptive scanning method for a pipe socket of ductile cast iron pipe according to claim 3, characterized in that, The scanning track is generated according to the teaching point and information of the first sensor and the second sensor, and the robot scans the socket, which comprises the following steps: 1) Teaching point coordinate calculation: The pipe diameter offset amount b of points 2 to 10 in y and z axes is calculated and accumulated to the original coordinates; 2) Offset amount calculation: The entering offset amount a of points 3 to 9 in x axis is calculated and accumulated to the original coordinates; 3) Deflection angle adjustment: after the accumulation of the pipe diameter offset b and the extension offset a, the imaging effect is observed, and the rotation angle of the robot in the y-axis and z-axis is adjusted to make the imaging without inclination and bending.

6. The self-adaptive scanning method for a pipe socket of ductile cast iron pipe according to claim 5, characterized in that, The pipe diameter offset b is obtained from (actual pipe diameter-default pipe diameter) / 2; wherein the default pipe diameter is the set pipe diameter, and the actual pipe diameter is the pipe diameter data obtained by the second sensor.

7. The self-adaptive scanning method for a pipe socket of ductile cast iron pipe according to claim 5, wherein, The pipe diameter offset b of the y-axis and z-axis is as follows: The y-axis offset of point 2 is 0, and the z-axis offset is b; The y-axis offset of point 3 is 0, and the z-axis offset is b; The y-axis offset of point 4 is b, and the z-axis offset is 0; The y-axis offset of point 5 is 0, and the z-axis offset is-b; The y-axis offset of point 6 is-b, and the z-axis offset is 0; The y-axis offset of point 7 is 0, and the z-axis offset is b; The y-axis offset of point 8 is b The z-axis offset of point 8 is b ; The y-axis offset of point 9 is 0, and the z-axis offset is b; The y-axis offset of point 10 is 0, and the z-axis offset is b.

8. The self-adaptive scanning method for a pipe socket of ductile cast iron pipe according to claim 5, wherein, The extension offset a is obtained by the following steps: The distance value m of the distance sensor from the pipe socket end surface is obtained by the first sensor, the robot is extended into the socket in the x direction from point 3 to stop at the scanning position, and the x-axis offset of this position from point 3 is recorded as n at this time; the difference between the edge finding value t measured by the first sensor and m is added to n, which is the extension offset a.

9. An adaptive scanning system for a ductile iron pipe bell, characterized by, It includes: The first sensor is arranged at the center position opposite to the socket stay, which is used to determine the distance of the robot scanning; The second sensor is arranged directly above the pipe when it stays, which is used to determine the pipe diameter; The trajectory generation unit is used to generate a scanning trajectory according to the teaching point position and the information of the first sensor and the second sensor; The robot is used to scan the socket according to the scanning trajectory; The camera is arranged at the front end of the robot six-axis flange, the lens is perpendicular to the x-axis of the robot, and is used for image acquisition; The PLC is used for data communication between the sensor, the robot, and the camera, as well as triggering of the robot action and the camera work.

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