Automatic detection and automatic qualification judgment method for national standard lifting hook

Abstract

The invention discloses an automatic detection and automatic qualification judgment method for a national standard lifting hook, and belongs to the technical field of lifting hook detection. Comprising the following steps: S1, lowering a national standard lifting hook to be detected to a collection height suitable for a 3D sensor for collecting three-dimensional coordinate sizes, performing three-dimensional scanning on a front view surface and a side view surface of the lifting hook, and collecting three-dimensional scanning coordinate values; s2, executing the automatic detection process of the dangerous section size and the torsion angle of the hook body of the national standard lifting hook; step S21, converting the three-dimensional scanning value into a two-dimensional scanning value; step S22, carrying out automatic calculation processing on the dangerous section size and the torsion angle of the hook body on the two-dimensional coordinate data selected in the step S21; step S23, automatically judging whether the dangerous section size and the torsion angle of the hook body are qualified or not; according to the automatic detection and automatic qualification judgment method for the national standard lifting hook, automatic detection and qualification judgment of the lifting hook can be achieved, the inspection workload is effectively reduced, and the inspection efficiency is improved.

Description

Technical Field

[0001] The present invention relates to an automatic detection and automatic qualification determination method for national standard lifting hooks, belonging to the technical field of lifting hook detection. Background Art

[0002] A lifting hook is one of the most common lifting tools in hoisting machinery. Its safety is directly related to the safety of operators and the surrounding environment. Long-term use and friction will cause wear on the surface of the lifting hook, thereby affecting its load-bearing capacity and safety. When the load borne by the lifting hook exceeds its design capacity, it may lead to serious consequences such as deformation and fracture of the lifting hook; if the lifting hook has cracks, deformation, or severe wear, the load-bearing capacity will be greatly reduced, and in this case, using it is likely to cause the suspended load to fall and cause major safety accidents.

[0003] To avoid the occurrence of safety accidents, it is usually necessary to conduct safety inspections on lifting hooks. The current common practice is to manually measure the dangerous cross-section dimensions and opening deviation dimensions using measuring tools such as a ruler or caliper, and then compare with the original dimensions when the lifting hook leaves the factory and manually calculate the deviation rate to determine whether it meets the scrapping standard; however, the above measurement methods have the following problems: (1) large on-site measurement errors and poor consistency; due to manual measurement, each measurement point is different, resulting in measurement errors and poor consistency of multiple measurement results; (2) unable to effectively measure the torsional deformation degree of the hook body; the torsional deformation degree of the hook body is the result of a three-dimensional deformation. Simply manually measuring two-dimensional data and then calculating the angle will result in large errors and make the measurement results invalid; (3) for the issues of whether it is qualified and whether it meets the scrapping standard, manual calculation and determination are used, increasing the workload of testers and reducing work efficiency; therefore, in order to solve the above problems, there is an urgent need to propose an automatic detection and automatic qualification determination method for national standard lifting hooks. Summary of the Invention

[0004] To solve the above problems, the present invention proposes an automatic detection and automatic qualification determination method for national standard lifting hooks, which can achieve automatic detection and qualification determination, effectively reduce the inspection workload, improve the detection efficiency, and can solve the problems of large measurement errors and poor consistency. At the same time, it can accurately measure the torsional angle of the hook body.

[0005] The automatic detection and automatic qualification determination method for national standard lifting hooks of the present invention includes the following steps:

[0006] Step S1, lower the national standard lifting hook to be tested to a height suitable for the 3D sensor for collecting three-dimensional coordinate dimensions, and perform three-dimensional scanning on a front view surface and a side view surface of the lifting hook to collect three-dimensional scanning coordinate values;

[0007] Step S2, execute the automatic detection process of the dangerous cross-section dimensions and the torsional angle of the national standard lifting hook,

[0008] Step S21: First, convert the three-dimensional scan values into two-dimensional scan values. Use the orthographic projection algorithm to convert the three-dimensional scene of the front view of the hook into a two-dimensional planar image, and obtain the two-dimensional coordinates (x, y).

[0009] Step S22: Automatically calculate and process the dangerous section size and the hook body torsion angle for the two-dimensional coordinate data selected in Step S21. The process is as follows:

[0010] Step S221: Calculate the size of the dangerous section A-A.

[0011] Use the maximum value Xa1 of x in the scan values to find a coordinate point A1(Xa1, Ya1) of the dangerous section A-A. Among the x coordinate points with the same Ya1, find the minimum value Xa4 and the x coordinate point values Xa2 and Xa3 that show a jump change adjacent to it, where Xa2 > Xa3 > Xa4. Thus, determine that the coordinate value of another coordinate point A2 of the dangerous section A-A is (Xa2, Ya1). Calculate using Xa1 - Xa2 = H1, and the calculation result H1 is the size of the dangerous section A-A.

[0012] Step S222: Calculate the size of the dangerous section B-B.

[0013] Use the maximum value Yb0 of the y-axis at the top in the scan values. Among the x coordinate points with the same Yb0, find the maximum value Xmax and the minimum value Xmin of x. Then take (Xmax - Xmin) / 2 of the x coordinate value as Xb0, and take the point with the coordinate value (Xb0, Yb0) as the first coordinate point of the dangerous section B-B, denoted as point B0. Among the (Xb0, y) coordinate values with the same Xb0, find the minimum value Ymin of y, thus determining that the coordinate value of the second coordinate point B2 of the dangerous section B-B is (Xb0, Ymin). Among the two y coordinate values Y1 and Y2 that show a jump change adjacent to the two adjacent y coordinate values with the same Xb0 coordinate, where Y1 > Y2. Thus, determine that the coordinate value of the third coordinate point B1 of the dangerous section B-B is (Xb0, Y2). Calculate using Y2 - Ymin = H2, and the calculation result H2 is the size of the dangerous section B-B.

[0014] Step S223: Calculate the opening degree.

[0015] It can be known from the fact that the collision and friction point where the sling slides into the hook is the most convex point of the contact surface that the x - coordinate value of the most convex point on the upper contact surface between the sling and the hook is less than Xbo; therefore, among the selected calculation variables, the x - coordinate value XK1 takes the set of scanned values in Xmin≤X≤Xbo; for the y - coordinate value YK1 in the selected calculation variables, YK1 takes the set of scanned values in Y1≤Yk1≤Ybo, and the coordinate point variable (XK1, YK1) is taken as one of the calculation variables;

[0016] Similarly, it can be known from the fact that the collision and friction point where the sling slides into the hook is the most convex point of the contact surface that the x - dimension value of the most convex point on the lower contact surface between the sling and the hook is less than or equal to Xa3; therefore, the x - coordinate value variable XK2 is selected, and XK2 takes the set of scanned values of Xk2≤Xa3; the Y - coordinate point variable YK2 is the y - coordinate scanned value corresponding to the XK2 coordinate point variable, and the coordinate point variable (XK2, YK2) is taken as the second calculation variable;

[0017] According to the Pythagorean theorem, the difference in the coordinate points of the above - mentioned two variables forms the right - angled sides to calculate the hypotenuse, and the minimum hypotenuse length is the minimum opening degree of the hook. Therefore, the minimum opening degree of the hook is calculated as Taking the minimum value A2min is the opening degree of the hook, and at the same time, the two endpoint coordinate points of the hook opening are determined as (Xk01, Yk01) and (Xk02, Yk02);

[0018] Step S224, calculate the torsion angle of the hook body,

[0019] The y - coordinate position of the origin of the torsion angle is at the 1 / 2 of the dangerous section B - B, that is, the origin y - coordinate value is H2 / 2. By calculating, the origin y - coordinate value is (Yk2 - Ymin) / 2, and thus the three - dimensional origin coordinates are determined as (0,

[0020] (Yk2 - Ymin) / 2, 0). According to the opening endpoint coordinate value (Xk02, Yk02) of the hook obtained in the previous step, find the corresponding three - dimensional coordinate point (Xk02, Yk02, Z). According to the arctangent function y = arctanx, where x is the value of the opposite side of the torsion angle divided by the value of the adjacent side, the value of the opposite side is determined as Z, and the adjacent side is Yk02-(Y2 - Ymin) / 2. Through the calculation formula x = Z / Yk02-(Y2 - Ymin) / 2, and finally, the torsion angle α of the hook body is obtained through the arctangent function operation;

[0021] Step S23, automatically determine whether the dangerous section size and the hook - body torsion angle are qualified. The process is as follows:

[0022] The standard value data of the national standard hook is provided through the factory information. The standard value data in the factory information is pre-entered into the database for preparation to participate in the calculation. Among them, the standard values include: the lateral stress surface A-A of the dangerous section is H1', the bottom stress surface B-B of the dangerous section is H2', and the opening degree is A2'. From the above results, it can be calculated that:

[0023] The wear rate of the dangerous section A-A is (H1'-H1) / H1'. If the calculation result is greater than 10%, it is determined as unqualified;

[0024] The wear rate of the dangerous section B-B is (H2'-H2) / H2'. If the calculation result is greater than 10%, it is determined as unqualified;

[0025] The wear rate of the opening degree is (A2'-A2) / A2'. If the calculation result is greater than 15%, it is determined as unqualified;

[0026] If the torsion angle α of the hook body is greater than 10°, it is determined as unqualified;

[0027] If any item is unqualified, it is determined that the hook should be scrapped.

[0028] Further, in the step S21, when using the orthographic projection algorithm to convert the three-dimensional scene of the front view of the hook into a two-dimensional plane image, the specific conversion operation is as follows: The conversion matrix is a 3×3 matrix multiplied by the (x, y, z) coordinate system to be converted, which is expressed as: Among them, the scaling factor 1 corresponds to the x and y axes, and the z-axis component is set to zero: The three-dimensional coordinates (x, y, z) are multiplied by the orthographic projection matrix to obtain the two-dimensional coordinates (x, y).

[0029] Compared with the prior art, the automatic detection and automatic qualification determination method for the national standard hook of the present invention uses three-dimensional scanning technology and is combined with computer operation, which can quickly and accurately obtain the wear rate of the dangerous section of the hook, the wear rate of the opening degree of the hook, and the torsion angle value of the hook body, and realizes the automatic judgment of whether the hook needs to be scrapped; effectively reduces the workload of manual inspection and improves the detection efficiency; and can solve the problems of large errors and poor consistency caused by manual measurement; at the same time, uses the orthographic projection algorithm to convert the three-dimensional scan value into a two-dimensional scan value, and based on the two-dimensional coordinate value, finds the coordinate points participating in the calculation, and calculates the wear rate of the dangerous section of the hook, the wear rate of the hook, and the torsion angle value of the hook body using the coordinate point dimensions. The calculation is simple, easy to implement, has low requirements for computer computing power, is conducive to large-scale application, and solves the problems caused by manual measurement; and this method is not only applicable to the regular detection and determination of the hook during use, but also can be applied to the factory inspection and determination of the hook. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1Schematic diagram of the automatic detection and automatic determination process of the hook of the present invention.

[0031] Figure 2 Schematic diagram of the three-dimensional scanning range of the hook of the present invention;

[0032] Among them, Figure (a) is a three-dimensional scanning schematic diagram of the front view of the hook; Figure (b) is a three-dimensional scanning schematic diagram of the side view of the hook.

[0033] Figure 3 Two-dimensional schematic diagram of the calculated point coordinates of the front view of the hook of the present invention.

[0034] Figure 4 Two-dimensional schematic diagram of the calculated point coordinates of the side view of the hook of the present invention. Specific implementation manner

[0035] Example 1:

[0036] Such as Figure 1 The automatic detection and automatic pass determination method for the national standard hook shown includes the following steps:

[0037] Step S1, lower the national standard hook to be tested to a suitable height for the 3D sensor to collect three-dimensional coordinate dimensions, and perform three-dimensional scanning on one front view and one side view of the hook to collect three-dimensional scanning coordinate values, such as Figure 2 Shown;

[0038] Step S2, perform the automatic detection process of the dangerous section size and the hook body torsion angle of the national standard hook,

[0039] Step S21, first convert the three-dimensional scanning value into a two-dimensional scanning value, and use the orthographic projection algorithm to convert the three-dimensional scene of the front view of the hook into a two-dimensional plane image. The specific conversion operation is as follows: The conversion matrix uses a 3×3 matrix multiplied by the (x, y, z) coordinate system to be converted, which is expressed as: Among them, the scaling factor 1 corresponds to the x and y axes, and the z-axis component is set to zero: The three-dimensional coordinates (x, y, z) are multiplied by the orthographic projection matrix to obtain the two-dimensional coordinates (x, y);

[0040] Step S22, perform automatic calculation and processing of the dangerous section size and the hook body torsion angle on the two-dimensional coordinate data selected in step S21. The process is as follows:

[0041] Step S221, calculate the size of the dangerous section A-A,

[0042] Such as Figure 3As shown in the figure, the maximum value Xa1 of x in the scanned values is used to find a coordinate point A1(Xa1, Ya1) of the dangerous section A-A. Among the x coordinate points with the same number of Ya1, the minimum value Xa4 is found, as well as the x coordinate point values Xa2 and Xa3 with jump changes adjacent to it, where Xa2 > Xa3 > Xa4. Thus, the coordinate value of another coordinate point A2 of the dangerous section A-A is determined to be (Xa2, Ya1), and it is calculated using Xa1 - Xa2 = H1. The calculation result H1 is the size of the dangerous section A-A.

[0043] Step S222, calculate the size of the dangerous section B-B.

[0044] As Figure 3 shown in the figure, the maximum value Yb0 of the uppermost y-axis in the scanned values is used. Among the x coordinate points with the same number of Yb0, the maximum value Xmax and the minimum value Xmin of x are found. Then, (Xmax - Xmin) / 2 of the x coordinate value is taken as Xb0, and the point with the coordinate value (Xb0, Yb0) is used as the first coordinate point of the dangerous section B-B, denoted as point B0. Among the (Xb0, y) coordinate values with the same Xb0, the minimum value Ymin of y is found, so as to determine the coordinate value (Xb0, Ymin) of the second coordinate point B2 of the dangerous section B-B. Among the two y coordinate values Y1 and Y2 with jump changes adjacent to each other under the same Xb0 coordinate, where Y1 > Y2. Thus, the coordinate value (Xb0, Y2) of the third coordinate point B1 of the dangerous section B-B is determined, and it is calculated using Y2 - Ymin = H2. The calculation result H2 is the size of the dangerous section B-B.

[0045] Step S223, calculate the opening degree.

[0046] According to the fact that the collision and friction point where the sling slides into the hook is the most convex point of the contact surface, it can be known that the x coordinate value of the most convex point on the upper contact surface between the sling and the hook is less than Xbo. Therefore, the x coordinate value XK1 in the selected calculation variables takes the set of scanned values where Xmin ≤ X ≤ Xbo; the y coordinate value YK1 in the selected calculation variables, YK1 takes the set of scanned values where Y1 ≤ Yk1 ≤ Ybo, that is, the value range of (XK1, YK1) is the shaded part in the hook handle as Figure 3 shown in the figure, and the coordinate point variable (XK1, YK1) is used as one of the calculation variables.

[0047] Similarly, according to the fact that the collision and friction point where the sling slides into the hook is the most convex point of the contact surface, it can be known that the x dimension value of the most convex point on the lower contact surface between the sling and the hook is less than or equal to Xa3. Therefore, the x coordinate value variable XK2 is selected, and XK2 takes the set of scanned values where Xk2 ≤ Xa3; the Y coordinate point variable YK2 is the y coordinate scanned value corresponding to the XK2 coordinate point variable, that is, the value range of (XK2, YK2) is asFigure 3 The shaded part in the hook tip shown, and the coordinate point variables (XK2, YK2) are used as the second of the calculation variables;

[0048] According to the Pythagorean theorem, it is known that the difference in the coordinate points of the shaded area where the above two variables are located forms the right-angled sides to calculate the hypotenuse. The minimum hypotenuse length is the minimum opening degree of the hook. Therefore, the minimum opening degree of the hook is calculated as

[0049] Taking the minimum value A2min is the opening degree of the hook. At the same time, the coordinate points of the two endpoints of the hook opening are determined as (Xk01, Yk01) and (Xk02, Yk02);

[0050] Step S224, calculate the torsion angle of the hook body,

[0051] The y-coordinate position of the origin of the torsion angle is at the 1 / 2 of the dangerous section B-B, that is, the y-coordinate value of the origin is H2 / 2. Through the attachment Figure 3 It can be calculated that the y-coordinate value of the origin is (Yk2 - Ymin) / 2. Thus, the Figure 4 three-dimensional origin coordinates in the attachment are (0, (Yk2 - Ymin) / 2, 0). According to the opening endpoint coordinate values (Xk02, Yk02) of the hook obtained in the previous step, find the corresponding three-dimensional coordinate point (Xk02, Yk02, Z). According to the arctangent function y = arctanx, x is the opposite side value of the torsion angle divided by the adjacent side value. The opposite side value is determined as Z, and the adjacent side is Yk02 - (Y2 - Ymin) / 2. Through the calculation formula x = Z / Yk02 - (Y2 - Ymin) / 2, finally, the torsion angle α of the hook body is obtained through the arctangent function operation;

[0052] Step S23, automatically determine whether the dangerous section size and the hook body torsion angle are qualified. The process is as follows:

[0053] The standard value data of the national standard hook are provided through the factory data. The standard value data in the factory data are pre-entered into the database for preparation to participate in the calculation. Among them, according to the national standard GB10051 and related safety inspection and scrapping standards, when the hook appears in one of the following situations, it should be scrapped: the wear of the dangerous section reaches 10% of the original size; the opening degree increases by 15% compared with the original size; the hook body torsion deformation exceeds 10°; the hook manufacturer also clearly marks the original size of the lateral stress surface A-A of the dangerous section on the drawing and data in the factory data. The dimension line of this section is the vertical line passing through the center point of the hook handle and the center of the maximum simulated sling in the hook, the original size of the bottom stress surface B-B. The dimension line of this section is the horizontal line passing through the outermost convex point of the hook body and the center of the maximum simulated sling in the hook, and the original size A2 of the hook opening, that is, the minimum opening size;

[0054] In the present invention, the factory standard values of the lifting hook are recorded as follows: for the lateral stress surface A-A of the dangerous section, it is H1'; for the bottom stress surface B-B of the dangerous section, it is H2'; and the opening degree is A2'. From the above results, it can be calculated that:

[0055] The wear rate of the dangerous section A-A is (H1'-H1) / H1'. If the calculated result is greater than 10%, it is determined as unqualified;

[0056] The wear rate of the dangerous section B-B is (H2'-H2) / H2'. If the calculated result is greater than 10%, it is determined as unqualified;

[0057] The wear rate of the opening degree is (A2'-A2) / A2'. If the calculated result is greater than 15%, it is determined as unqualified;

[0058] If the torsional angle α of the hook body is greater than 10°, it is determined as unqualified;

[0059] If any one item is unqualified, it is determined that the lifting hook should be scrapped.

[0060] The automatic detection and automatic qualification determination method for national standard lifting hooks of the present invention further includes the associated setting of the lifting hook detection time and the lifting hook detection result. The computer is used to record, count, and store the data during the safety detection process of the lifting hook. At the same time, the usage conditions of the detected lifting hook are recorded, including the usage environment, usage time, usage load, surface wear conditions, etc.; the lifting hooks in different usage environments are classified, and the scrapping conditions of the lifting hooks used in different scenarios are analyzed in cooperation with the computer based on the lifting hook detection data. And through the scrapping conditions of the lifting hooks, the detection time interval of the lifting hooks is adjusted, so as to achieve the adaptive adjustment of the lifting hook detection; it can not only ensure the safety of the lifting hook usage, but also the detection time of the lifting hook can be adaptively adjusted according to the lifting hooks in different usage environments, with good mobility and more flexible detection; in addition, through the storage record of the computer, it is convenient for subsequent data retrieval, and the usage environment of the lifting hook is adjusted according to the scrapping conditions of the lifting hook, so as to extend the service life of the lifting hook.

[0061] The automatic detection and automatic qualification determination method for national standard lifting hooks of the present invention adopts three-dimensional scanning technology and is combined with computer operation, which can quickly and accurately obtain the wear rate of the dangerous section of the lifting hook, the wear rate of the opening degree of the lifting hook, and the torsional angle value of the hook body, and realize the automatic judgment of whether the lifting hook needs to be scrapped; at the same time, the orthographic projection algorithm is used to convert the three-dimensional scan value into a two-dimensional scan value, and the coordinate points participating in the calculation are found based on the two-dimensional coordinate values. The wear rate of the dangerous section of the lifting hook, the wear rate of the lifting hook, and the torsional angle value of the hook body are calculated using the coordinate point dimensions. The calculation is simple, easy to implement, has low requirements for computer computing power, is conducive to large-scale application, and solves the problems caused by manual measurement;

[0062] In addition, this method is not only applicable to the regular inspection and determination of the lifting hook during use, but also can be applied to the factory inspection and determination of the lifting hook. Among them, during the regular inspection of the lifting hook, the computer can record and store the lifting hook data, and cooperate with the above data analysis to determine the scrapping situation of the lifting hook used in different scenarios, so as to adjust the inspection time interval of the lifting hook in a timely manner to ensure the safety of the lifting hook during use.

[0063] The above embodiments are only preferred embodiments of the present invention. Therefore, all equivalent changes or modifications made according to the structures, features and principles described in the scope of this invention patent application are included in the scope of this invention patent application.

Claims

1. A method for automatic detection and automatic qualification determination of national standard hooks, characterized in that: The following steps are involved: Step S1, lowering the national standard hook to be tested to a suitable acquisition height for the 3D sensor used to collect three-dimensional coordinate dimensions, performing three-dimensional scanning on a front view surface and a side view surface of the hook, and collecting three-dimensional scanning coordinate values; Step S2, executing the automatic detection process of the dangerous section size and hook body torsion angle of the national standard hook, Step S21, first convert the three-dimensional scanning value into a two-dimensional scanning value, use the orthographic projection algorithm to convert the three-dimensional scene of the front view of the hook into a two-dimensional plane image, and obtain the two-dimensional coordinates (x, y); Step S22, automatically calculating and processing the dangerous section size and hook body torsion angle of the two-dimensional coordinate data selected in step S21, the process is as follows: Step S221, calculating the size of the dangerous section AA, denoted as H1; Step S222, calculating the size of the dangerous section BB, denoted as H2; Step S223, calculating the opening degree, recorded as A2; Step S224, calculating the hook body twisting angle, denoted as α; Step S23, automatically judging whether the dangerous section size and hook body torsion angle are qualified, the process is as follows: The standard value data of the national standard hook is provided by the factory data. The standard value data in the factory data is entered into the database in advance for calculation. Among them, the standard values ​​include: the lateral force surface AA of the dangerous section, recorded as H1', ​​the force surface BB at the bottom of the dangerous section, recorded as H2', and the opening degree, recorded as A2'; calculated from the above results: The wear rate of the dangerous section AA is (H1'-H1) / H1'. If the calculated result is greater than 10%, it is judged as unqualified; The wear rate of the dangerous section BB is (H2'-H2) / H2'. If the calculated result is greater than 10%, it is judged as unqualified; The opening wear rate is (A2'-A2) / A2'. If the calculated result is greater than 15%, it is judged as unqualified; If the hook body twist angle α is greater than 10°, it is judged as unqualified; If one item fails, the hook will be scrapped.

2. The method for automatic detection and automatic qualification determination of national standard hooks according to claim 1 is characterized in that: In step S21, when the orthographic projection algorithm is used to convert the three-dimensional scene of the front view of the hook into a two-dimensional plane image, the specific conversion operation is as follows: the conversion matrix uses a 3×3 matrix multiplied by the converted (x, y, z) coordinate system, expressed as: Here, a scaling factor of 1 corresponds to the x and y axes, while the z-axis component is set to zero: The three-dimensional coordinate (x, y, z) is multiplied by the orthographic projection matrix to obtain a two-dimensional coordinate (x, y).

3. The method for automatic detection and automatic qualification determination of national standard hooks according to claim 1 is characterized in that: The specific operation steps of step S221 are as follows: use the maximum x value Xa1 in the scan value to find a coordinate point A1 (Xa1, Ya1) of the dangerous section AA, find the minimum value Xa4 among the x coordinate points with the same number of Ya1, and the adjacent x coordinate point values ​​Xa2 and Xa3 that have a jump change, where Xa2>Xa3>Xa4; thereby determining that the coordinate value of another coordinate point A2 of the dangerous section AA is (Xa2, Ya1), and use Xa1-Xa2=H1 for calculation, and the calculation result H1 is the size of the dangerous section AA.

4. The method for automatic detection and automatic qualification determination of national standard hooks according to claim 3 is characterized in that: The specific operation steps of step S222 are as follows: using the uppermost y-axis maximum value Yb0 in the scan value, find the x maximum value Xmax and the x minimum value Xmin among several x-coordinate points with the same Yb0, then take the x-coordinate value (Xmax-Xmin) / 2 as Xb0, and take the point with the coordinate value (Xb0, Yb0) as the first coordinate point of the dangerous section BB, recorded as point B0; find the minimum y value Ymin in the (Xb0, y) coordinate value in the same Xb0, so as to determine the coordinate value (Xb0, Ymin) of the second coordinate point B2 of the dangerous section BB; find two y-coordinate values ​​Y1 and Y2 with jump changes between the y coordinates and the adjacent values ​​under the same Xb0 coordinate, where Y1>Y2; thereby determine the coordinate value (Xb0, Y2) of the third coordinate point B1 of the dangerous section BB, and use Y2-Ymin=H2 for calculation, and the calculation result H2 is the size of the dangerous section BB.

5. The method for automatic detection and automatic qualification determination of national standard hooks according to claim 4 is characterized in that: The specific operation steps of step S223 are as follows: according to the collision friction point when the sling slides into the hook as the most convex point of the contact surface, it can be known that the x coordinate value of the most convex point on the contact surface between the sling and the hook is less than Xbo; therefore, the x coordinate value XK1 in the selected calculation variable is the set of scan values ​​in Xmin≤X≤Xbo; the y coordinate value YK1 in the calculation variable is selected, and the value of YK1 is the set of scan values ​​in Y1≤Yk1≤Ybo, and the coordinate point variable (XK1, YK1) is used as one of the calculation variables; Similarly, according to the collision and friction point when the sling slides into the hook as the most convex point of the contact surface, it can be known that the x dimension value of the most convex point of the contact surface between the sling and the hook is less than or equal to Xa3; therefore, the x coordinate value variable XK2 is selected, and the value of XK2 is the scanning value set of Xk2≤Xa3; the Y coordinate point variable YK2 is the y coordinate scanning value corresponding to the XK2 coordinate point variable, and the coordinate point variable (XK2, YK2) is used as the second calculation variable; According to the Pythagorean theorem, the coordinate difference of the above two variables is known to form a right angle to calculate the hypotenuse. The minimum hypotenuse length is the minimum opening of the hook. Therefore, the minimum opening of the hook is calculated as The minimum value A2min is the opening degree of the hook, and the coordinate points of the two end points of the hook opening are determined as (Xk01, Yk01) and (Xk02, Yk02).

6. The method for automatic detection and automatic qualification determination of national standard hooks according to claim 5 is characterized in that: The specific operation steps of step S224 are as follows: the y coordinate position of the origin of the torsion angle is at 1 / 2 of the dangerous section BB, that is, the y coordinate value of the origin is H2 / 2. By calculating the y coordinate value of the origin (Yk2-Ymin) / 2, the three-dimensional origin coordinate is determined to be (0, (Yk2-Ymin) / 2, 0). According to the coordinate value of the open end point on the hook obtained in the previous step is (Xk02, Yk02), find the corresponding three-dimensional coordinate point (Xk02, Yk02, Z). According to the inverse tangent function y=arctanx, x is the opposite side value of the torsion angle divided by the adjacent side value. The opposite side value is determined to be Z, and the adjacent side is Yk02-(Y2-Ymin) / 2. By calculating the formula x=Z / Yk02-(Y2-Ymin) / 2, the hook body torsion angle α is finally obtained through the inverse tangent function operation.

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