A high-temperature ladle hanging safety monitoring method based on topography predefinition line laser

Abstract

The application provides a high-temperature ladle hanging safety monitoring method based on a topographic pre-defined line laser, and belongs to the technical field of ladle safety monitoring. The method first acquires the shape of a correctly assembled current object to be detected ladle trunnion and hook, designs a pre-defined line laser, and designs a variable-curvature / variable-bending detection structure line; after receiving a detection request signal, an industrial projection light machine spatial light modulator projects a pre-defined variable-curvature line laser to a ladle hook hanging position to be detected, then an imaging analysis system photographs a current projected modulated line laser image, and performs straightness analysis and calculation on the collected modulated pre-defined line laser, and finally the straightness analysis and calculation result is used as a judgment basis to judge whether the hanging is normal, and the detection task is completed. The application only needs to judge the straightness of the collected line laser pattern, so as to judge whether the hoisting is correct, and has the advantages of fast recognition speed, strong environment adaptation, high recognition accuracy and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ladle safety monitoring, and particularly relates to a high-temperature ladle hanging safety monitoring method based on a topography pre-defined line laser. BACKGROUND

[0002] In the field of modern steel smelting safety production, correct hanging and stable hoisting of a ladle plays a key role in effectively preventing major safety accidents such as ladle tilting and even ladle falling. With the introduction of various policy plans in the field of safety production by the state, the continuous improvement of the safety production consciousness of the industry, and the development of metallurgical production science and technology, steel production enterprises have an urgent need for automatic safety monitoring and detection of ladle hoisting.

[0003] Currently, the conventional ladle hoisting monitoring method in the industry still mainly relies on manual visual inspection, which has many limitations and problems such as uncertainty. Specifically, ground personnel visually issue commands, and crane operators rely on visual inspection in the control room to ensure that the left and right hooks of the crane are hooked to the two ears of the ladle (hanging shaft bodies located on the outer side of the upper end of the ladle) at the same time. At the moment of lifting the ladle, if one of the hooks is not hooked to the ear, it will directly lead to the occurrence of ladle falling and overturning accidents. At the same time, the high-temperature, high-noise, and high-smoke environment of the steel production site will continuously interfere with the normal judgment of the ground personnel and the crane operators. The existence of the above problems makes it difficult to avoid errors in the traditional manual safety judgment of ladle hanging, thereby causing serious accident hazards and even directly leading to ladle falling accidents, resulting in immeasurable personal injury and production and economic losses.

[0004] In recent years, non-contact online detection technology based on machine vision structured light measurement methods has been widely used in various engineering measurement fields mainly for three-dimensional measurement. The core idea of the structured light method is to use a visual device to collect and analyze the light / pattern with structure information projected onto the surface of the measured object, which is modulated by the three-dimensional structure information of the measured object surface, to obtain the three-dimensional structure / topography of the measured object surface. Based on the above principle, a common type of structured light measurement technology is a binocular camera combined with a blue light projection light machine. The blue light projection light machine projects sinusoidal fringes onto the surface of the measured object, and the binocular camera collects the modulated sinusoidal fringes. Through a post-end phase unwrapping algorithm, a camera stereo matching relationship is established, and finally the full-field surface topography of the measured object is reconstructed.

[0005] However, for ladle hook identification and monitoring applications, on the one hand, there is a lack of special structured light fast identification method system for hook lifting objects, and on the other hand, the special environment of the steel plant will also cause serious interference to the imaging and light source projection of conventional machine vision and structured light measurement. Specifically embodied as follows: First, the ladle hook lifting monitoring requirement has the characteristics of high real-time requirement and measurement requirement determination. The existing structured light measurement method needs to project multiple sinusoidal fringe patterns onto the surface of the measured object, then step by step collect multiple modulated sinusoidal fringes, and finally use the phase unwrapping algorithm to reconstruct the three-dimensional structure of the measured object. Finally, the assembly condition of the hook and the trunnion is judged by means of algorithm. The time consumption of the above steps will seriously reduce the speed of on-site production and affect the synchronization of production rhythm. At the same time, the measurement requirement of hook lifting is relatively determined, and the conventional full-field structured light measurement means. Most of the three-dimensional topographic information obtained by measurement does not play a decisive role in judging whether the hook lifting is correct or not, resulting in a large amount of data redundancy. Secondly, the conditions such as smoke and dust, high temperature equipment in the steel production site will also cause imaging interference problems to the conventional LED blue light projection equipment.

[0006] The existing ladle hook identification method mainly relies on laser radar point cloud measurement or photoelectric sensor to realize. For example, Chinese patent CN114758333A discloses “A recognition method and system for ladle unhooking of a casting crane traveling crane”, which uses laser radar to collect point cloud data, performs three-dimensional reconstruction, obtains the position of the hook and the trunnion in real time, calculates the distance between the hook and the trunnion, and alarms when the distance exceeds the threshold. Chinese patent CN217766843U discloses “Ladle unhooking detection device”, which uses laser radar, image acquisition unit and inertia measurement unit installed on the laser radar to detect. The laser radar is used to collect the relative position laser mileage data between the crane hook and the ladle trunnion through the radar collection hole. Chinese patent CN216129232U discloses “Ladle hook identification intelligent detection device”, which uses photoelectric sensors installed on the ladle and the hook respectively to confirm whether the hook is in the correct position through the position relationship between the photoelectric sensor and the reflector.

[0007] The above methods have advantages, but their disadvantages are also very obvious. For example, the laser radar method needs to perform noise reduction, point cloud fitting, three-dimensional reconstruction, hook / ear identification, and center / center of gravity identification after scanning the point cloud. The above operations need to be calculated by the computer at each hook identification time, and the time-consuming multiple image processing operations will reduce the determination speed. The real-time performance of the method for determining the correct installation of the ladle hook is not strong, and the robustness of the multi-step operation method is not strong. The sensor ranging method uses a photoelectric emitter and a photoelectric receiver to determine whether the ladle ear and the hook are parallel, and uses a reflective photoelectric sensor and a reflector to determine the correct position of the hook. The positions of the reflector and the reflective photoelectric sensor are designed in advance, and each step of movement of the hook corresponds to the corresponding reflector and reflective photoelectric sensor. Therefore, the position of the hook needs to be confirmed at each step of movement, and the real-time performance of the detection is not good.

[0008] Therefore, it is necessary to develop a test determination method suitable for hook hoisting monitoring and identification to meet the safety production requirements of ladle hoisting monitoring in steel enterprises.

[0009] Based on the above-mentioned "structured light method" core principle, the present application aims to design a method for high-temperature ladle hook hoisting process. In the process of ladle installation, an active projection structure light stripe pattern with "adapted to the structure characteristics of the ladle hook itself" is used, combined with a visual camera and an analysis algorithm to analyze the straightness of the structure light, to finally realize the rapid determination of correct installation, and provide an efficient and reliable identification analysis means for ladle hoisting safety monitoring in steel production. SUMMARY

[0010] The present application provides a high-temperature ladle installation safety monitoring method based on topographic pre-defined line laser. The pre-designed pre-defined line laser pattern is projected onto the outer surface of the ladle hook hoisting by hardware devices such as spatial light modulator and laser. The pre-defined line laser pattern has the "correct installation" adaptation characteristics. The pre-defined line laser pattern projected onto the "correct installation" hook structure is collected by the camera, and the straightness is determined by the straight line identification algorithm. If the straightness meets the requirements, it can be determined as "actual correct installation". The present application introduces the correct shape of the hook installation into the definition of the line laser structured light pattern, saving the subsequent algorithm determination process. Only the straightness of the collected line laser pattern needs to be determined to determine whether the installation is correct. The line laser used in the present application has the characteristics of high penetration and high temperature suitability, and can effectively penetrate the smoke environment to form a projection pattern on the surface of the high-temperature ladle. In summary, the implementation of the present method has the advantages of fast identification speed, strong environmental adaptation and high identification accuracy.

[0011] To achieve the above-mentioned application purposes, the technical solutions provided by the present application are as follows:

[0012] A kind of high temperature ladle hanging safety monitoring method based on topography predefinition line laser, including steps as follows:

[0013] S1, by reading the original design CAD three-dimensional appearance drawing of ladle and hook, the appearance topography (only need to be obtained in the method of the application) of the correct assembly of the ladle trunnion and hook to be detected is obtained;

[0014] S2, according to the correct assembly of the appearance topography obtained in step S1, design predefinition line laser, get the detection structure line of variable curvature-variable bending;

[0015] S3, initialize test system, wait for the detection request signal sent by ladle hoisting system;

[0016] S4, after receiving the detection request signal by test system, the spatial light modulator of industrial projection light machine projects predefinition line laser to the ladle hook hanging position to be detected;

[0017] S5, after spatial light modulator projects predefinition line laser, industrial control computer of test system automatically sends acquisition instruction to industrial camera, and industrial camera shoots the modulated line laser image (predefinition line laser is a "folding line", the surface of ladle hook is different in height, so that the folding line is projected on the high and low surface, becomes a straight line, which is the modulated process) of the current projected predefinition line laser in ladle hook hanging position;

[0018] S6, the imaging analysis function of industrial control computer in test system calls internal straight line detection algorithm, and the modulated line laser image collected in step S5 is analyzed and calculated by straightness;

[0019] S7, according to the straightness analysis calculation result in step S6, whether the hanging is normal is automatically judged, and test system sends judgment signal to the upper equipment through external port, completes monitoring process.

[0020] In step S2, according to the original design CAD three-dimensional appearance drawing of ladle and hook, a folding line is designed along the three-dimensional appearance bending direction of ladle and hook, and the folding line is predefinition line laser, which is used as variable curvature-variable bending detection structure line.

[0021] The test system is laser structured light projection system, including 1 industrial projection light machine, 1 industrial camera, 1 industrial control computer, and the positions of industrial projection light machine and industrial camera are calibrated according to the scene.

[0022] The straightness analysis calculation method in the step S6 includes Hough_line transformation and LSD fast straight line detection algorithm. Taking the LSD algorithm as an example, the LSD firstly calculates an angle between each pixel and a level-line to form a level-line field. Then, pixels with approximately same direction in the field are merged, so that a series of regions, which are called line support regions, are obtained. Each line support region is actually a group of pixels, and is a candidate of a line segment.

[0023] If a straight line is detected in the analysis in the step S6, it is proved that the current assembly form is qualified, and the hanging is normal. If no straight line is detected, it is determined that the hanging is abnormal, and an alarm signal is sent out.

[0024] The external port in the step S7 includes a serial port and an analog port.

[0025] Compared with the prior art, the technical scheme has at least the following beneficial effects:

[0026] The above scheme introduces the correct appearance of the hook into the definition of the line laser structured light pattern, saves the subsequent algorithm determination process, and only needs to determine the straightness of the collected line laser pattern to determine whether the hoisting is correct.

[0027] The line laser used in the application has the characteristics of high penetration and high temperature applicability, can effectively penetrate the smoke environment, and form a projection pattern on the surface of the high-temperature ladle.

[0028] The detection speed of the application is fast, and the main detection steps only include projection light, image acquisition and straight line analysis algorithm, avoiding the complex operations such as phase unwrapping of multiple images after image acquisition in the traditional structured light method.

[0029] In summary, the application establishes a method for accurately and quickly measuring the line structured light pre-defined according to the correct hanging appearance of the measured ladle, can quickly judge the hanging function under the condition of overcoming environmental interference, thereby realizing online automatic detection of hook hoisting without affecting the production efficiency, effectively promoting the development of steel smelting safety production technology. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0031] Figure 1 A flow chart of a high-temperature ladle hanging safety monitoring method based on a topography pre-defined line laser according to the present application;

[0032] Figure 2 A comparison between the pre-defined line laser used in the present application and the traditional linear structured light, wherein (a) is the pre-defined line laser in the present application, and (b) is the traditional linear structured light;

[0033] Figure 3 A schematic diagram of the pre-defined line laser used in the present application and the ladle hook hanging combination;

[0034] Figure 4 A schematic diagram of the on-site collection implementation of the present application;

[0035] Figure 5 A schematic diagram of the imaging result of the present application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without any creative effort fall within the scope of protection of the present application.

[0037] The present application provides a high-temperature ladle hanging safety monitoring method based on a topography pre-defined line laser.

[0038] As shown in Figure 1 , the method comprises the following steps:

[0039] S1, obtaining the correct assembly of the outer shape of the ladle trunnion and the hook by reading the original design CAD three-dimensional contour drawing of the ladle and the hook;

[0040] S2, designing a pre-defined line laser according to the correct assembly of the outer shape obtained in step S1 to obtain a variable curvature-variable bending detection structure line;

[0041] S3, initializing the test system and waiting for a detection request signal from the ladle hoisting system;

[0042] S4, after receiving the detection request signal, the test system projects the pre-defined line laser to the ladle hook hanging position to be detected by the spatial light modulator of the industrial projection light machine;

[0043] S5, after the spatial light modulator projects the predefined line laser, the industrial control computer of the test system automatically sends a collection instruction to the industrial camera, and the industrial camera shoots the modulated line laser image of the current projected predefined line laser at the ladle hook hanging position;

[0044] S6, the imaging analysis function of the industrial control computer in the test system calls the internal straight line detection algorithm to analyze and calculate the straightness of the modulated line laser image collected in step S5;

[0045] S7, according to the straightness analysis result in step S6, it is automatically judged whether the hanging is normal or not, and the test system sends a judgment signal to the upper device through the external port to complete the monitoring process.

[0046] The "predefined line laser structured light" used in the application is as shown in Figure 2 (a), and the specific line structure is generated according to the "correctly assembled hook structure". Compared with the traditional sinusoidal stripe or line laser structured light Figure 2 (b), the pre-defined curvature / breakline information has the surface topography information of the hook object to be detected, and the pre-defined line laser with the information will be further modulated by the hook structure position in the next step of projection.

[0047] The predefined line laser used in the application is projected to the ladle hook position as shown in Figure 3 , the pre-defined line laser with variable curvature / breakline is designed according to the topography of the correctly hung ladle, and finally projected to the outside of the ladle, so that the line laser matches the projected ladle hook position.

[0048] As shown in Figure 4 , by arranging the collection camera and the projection light machine equipment outside the ladle, only one projection of the pre-defined line laser is needed in the on-site monitoring state, and the image is collected synchronously, and then the straightness is judged by the approximate straight line of the two-dimensional digital image plane collected, so that the judgment result can be obtained.

[0049] In the on-site collection implementation of the application, first, an experimental test system is built, the DMD projection is turned off, the collection camera, the filter and the lens, the laser and the like are arranged according to the position of the ladle hook model to be measured, the DMD projection light machine is placed in front of the ladle hook model to be measured, the laser is located on one side of the DMD projection light machine, the collection camera is arranged on the other side of the DMD projection light machine, the collection camera faces the ladle hook model to be measured, and the filter is arranged between the collection camera and the ladle hook model to be measured; then the spatial light modulator (DMD projection light machine) of the industrial projection light machine projects the predefined line laser to the hook hanging position, and the current image is shot by the collection camera. Finally, the two-dimensional digital image of the target surface is imaged by the collection camera (as shown in Figure 5), to determine the straightness of the laser line; if the straight line cannot be searched by using an algorithm such as LSD, it indicates that an abnormal assembly occurs.

[0050] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A high-temperature ladle hanging safety monitoring method based on topography pre-defined line laser, characterized in that, The steps include the following: S1, by reading the ladle and hook original design CAD three-dimensional appearance drawing, obtaining the appearance of the ladle trunnion and hook correct assembly; S2, according to the correct assembly of the appearance morphology obtained in step S1, design a pre-defined line laser, get the variable curvature-variable bending detection structure line; The pre-defined line laser is a "fold line", the ladle hook surface has different height, so that the fold line is projected on the high and low surface, becomes a straight line, which is the modulation process; S3, initialize the test system, wait for the detection request signal from the ladle hoisting system; S4, after receiving the detection request signal, the test system projects the pre-defined line laser to the ladle hook hanging position to be detected by the spatial light modulator of the industrial projection light machine; S5, after the spatial light modulator projects the pre-defined line laser, the industrial control computer of the test system automatically sends acquisition instruction to the industrial camera, and the industrial camera shoots the modulated line laser image of the current projected pre-defined line laser on the ladle hook hanging position; S6, the imaging analysis function of the industrial control computer in the test system calls the internal straight line detection algorithm, and analyzes and calculates the straightness of the modulated line laser image collected in step S5; S7, according to the straightness analysis calculation result in step S6, automatically judge whether the hanging is normal, the test system sends the judgment signal to the upper device through the external port to complete the monitoring process; In step S7, if a straight line is detected in step S6 analysis, it proves that the current assembly form meets the requirements and the hanging is normal; if the straight line cannot be detected, it is judged that the hanging is abnormal, and an alarm signal is sent.

2. The method for high temperature ladle hanging safety monitoring based on topography pre-defined line laser according to claim 1, characterized in that, In step S2, according to the ladle and hook original design CAD three-dimensional appearance drawing, a fold line is designed along the three-dimensional appearance bending direction of the ladle and hook, which is the pre-defined line laser as the variable curvature-variable bending detection structure line.

3. The method for high temperature ladle hanging safety monitoring based on topography pre-defined line laser according to claim 1, characterized in that, The test system is a laser structure light projection system, which includes one industrial projection light machine, one industrial camera and one industrial control computer.

4. The method for high temperature ladle hanging safety monitoring based on topography pre-defined line laser according to claim 1, characterized in that, The straightness analysis calculation method in step S6 includes Hough_line transformation or LSD fast straight line detection algorithm.

5. The method for high temperature ladle hanging safety monitoring based on topography pre-defined line laser according to claim 1, characterized in that, The external port in step S7 includes serial port and analog port.

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