Crane double-hoisting-point synchronous control method based on machine vision detection

Abstract

The application discloses a crane double-hoisting-point synchronous control method based on machine vision detection and belongs to the technical field of automatic control, which comprises the following steps: visual detection equipment self-checking; a vision camera captures a clutch position photo, the photo is transmitted into an industrial control computer vision analysis software, the clutch position is acquired according to a clutch deep learning training algorithm, the position state of a synchronous shaft is judged, and real-time state information of the synchronous shaft is sent to a controller; the real-time state information of the synchronous shaft is compared with synchronous instruction input setting information in real time by the controller, the compliance and safety of the state of the synchronous shaft and the synchronous instruction input setting are identified, and corresponding control strategies are made. The application adopts the machine vision technology to detect the real-time position of the clutch, judges the separation and kneading state of the synchronous shaft, intelligently identifies the compliance and safety of the state of the synchronous shaft in combination with a system synchronous instruction input signal, outputs a synchronous control mode under the normal state of the synchronous shaft, and ensures normal operation of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automation control, in particular to a crane double-lifting-point synchronous control method based on machine vision detection. BACKGROUND

[0002] The crane belongs to special equipment, and when it is built, it is often considered to be multi-purpose, and as much as possible to meet the multi-working-condition lifting operation, such as single-hook operation, electrical synchronous operation and mechanical synchronous operation. Different operation modes are realized by the separation and kneading of the synchronous shaft. The traditional separation and kneading of the synchronous shaft are completed by multiple people, which is low in operation efficiency, high in labor intensity and high in operation risk.

[0003] In order to change the above defects, a manual clutch is introduced in recent years, which realizes the quick clutching of the synchronous shaft, is more convenient to switch, greatly improves the clutching efficiency, reduces the labor intensity of personnel and reduces the operation risk. However, the manual clutch has no travel detection device, and there is no interlocking between the control system, which cannot be intelligently judged and controlled. Once the manual clutch is abnormal, if the control system cannot perceive and respond in time, it will cause serious safety consequences.

[0004] The main reasons for the abnormality of the manual clutch are that the clutch is not separated and the personnel operation is abnormal. The clutch is not separated because the synchronous shaft is a high-speed shaft, the clutch is in contact with it for a long time, there is both rotary friction and high-frequency resonance, the clutch will slowly loosen and drive the synchronous shaft to separate. The main reason for the personnel operation abnormality is that the operator lacks experience and responsibility, the clutch is not in place, the synchronous shaft is not completely kneaded, and with the rotation of the high-speed shaft, the clutch will slowly loosen and drive the synchronous shaft to separate. Therefore, it is necessary to study a synchronous shaft real-time state detection method, which is associated with the control system and dynamically interlocked. SUMMARY

[0005] The present application aims to solve the problem that the manual clutch is abnormal in the prior art, which causes the crane to be unable to stop in time, and proposes a crane double-lifting-point synchronous control method based on machine vision detection, which uses machine vision technology to detect the real-time position of the clutch, judges the separation and kneading state of the synchronous shaft, and intelligently identifies the compliance and safety of the synchronous shaft state in combination with the system synchronous instruction input signal.

[0006] In order to achieve the above-mentioned application purpose, the technical scheme of the present application is as follows:

[0007] The crane double-lifting-point synchronous control method based on machine vision detection comprises the following steps:

[0008] Step a, using a vision analysis software installed in an industrial control computer to self-check a vision camera and a light source installed near the clutch, and performing the next step after the self-checking is successful;

[0009] Step b, the visual camera and the light source work simultaneously, take a snapshot of the clutch position, and transmit the photo into the industrial control computer vision analysis software;

[0010] Step c, the visual analysis software obtains the clutch position according to the clutch deep learning training algorithm, judges the synchronous shaft to belong to one of the states of separation, pinch, and intermediate abnormal position in combination with the calibration parameters, and sends the real-time state information of the synchronous shaft to the controller through the industrial control computer;

[0011] Step d, after the controller receives the real-time state information of the synchronous shaft, it compares it with the synchronous instruction input setting information in real time, identifies the compliance and safety of the synchronous shaft state with the synchronous instruction input setting, and makes corresponding control strategy;

[0012] Step e, after the controller judges the synchronous instruction output signal, it generates a frequency converter control word and sends it to the frequency converter, and the frequency converter controls the start and stop of the hoisting motor according to different control words to realize synchronous control of the crane under different operations.

[0013] Further, in step b, the camera is erected in the direction of the clutch, and the imaging plane of the camera is leveled with the horizontal plane, and the camera captures the clutch area image.

[0014] Further, in step c, the visual analysis software identifies the clutch position through the SIFT algorithm, and obtains the minimum enclosing rectangle of the clutch after preprocessing through gray scale conversion, edge detection, and contour screening, calculates the inclination angle of the central axis of the rectangle and the horizontal line, and then judges the working state of the clutch according to the angle.

[0015] Further, the edge detection is realized by using the Canny algorithm, and the steps include:

[0016] 1) Gaussian smoothing is performed on the input image to reduce the error rate;

[0017] 2) Calculate the gradient amplitude and direction to estimate the edge strength and direction at each point;

[0018] 3) According to the gradient direction, perform non-maximum suppression on the gradient amplitude;

[0019] 4) Use double threshold processing and connect edges to save the result to an edge map with the same size and type as the source image.

[0020] Further, after the contour screening processing, the minAreaRect() function is used to obtain the minimum circumscribed rectangle of the contour, which contains three attributes: 1) the center point of the rectangle, i.e. the centroid; 2) the side length, including the length and width; 3) the angle value; the rotation angle is obtained by calling the angle attribute, which is the inclination angle of the central axis of the rectangle and the horizontal line.

[0021] Further, in step d, the synchronization mode knob switch is connected to the controller through a signal cable, and the controller receives an input mode selected by the synchronization mode knob switch from single-hook operation, electrical synchronization operation and mechanical synchronization operation; the lifting point knob switch is connected to the controller through a signal cable, and the controller receives an input mode selected by the lifting point knob switch from lifting point 1 single-action, lifting point 2 single-action and double-lifting point linkage.

[0022] When the synchronization mode knob switch inputs single-hook operation, if the lifting point knob switch inputs lifting point 1 single-action or lifting point 2 single-action, the synchronization instruction input on the controller is set to correspond to lifting point 1 single-action or lifting point 2 single-action, and if the lifting point knob switch is double-lifting point linkage, the synchronization instruction input on the controller is set to operation selection exception.

[0023] When the synchronization mode knob switch is electrical synchronization operation, if the lifting point knob switch is lifting point 1 single-action or lifting point 2 single-action, the synchronization instruction input on the controller is set to operation selection exception, and if the lifting point knob switch is double-lifting point linkage, the synchronization instruction input on the controller is set to electrical synchronization operation.

[0024] When the synchronization mode knob switch is mechanical synchronization operation, if the lifting point knob switch is lifting point 1 single-action or lifting point 2 single-action, the synchronization instruction input on the controller is set to operation selection exception, and if the lifting point knob switch is double-lifting point linkage, the synchronization instruction input on the controller is set to mechanical synchronization operation.

[0025] Further, when the real-time state of the synchronization shaft is separated, if the controller synchronization instruction input is set to lifting point 1 single-action or lifting point 2 single-action, the corresponding synchronization instruction output is lifting point 1 single-action or lifting point 2 single-action, if the controller synchronization instruction input is set to electrical synchronization selection, the synchronization instruction output is electrical synchronization operation, if the controller synchronization instruction input is set to mechanical synchronization selection, the synchronization instruction output is mode selection fault, and if the controller synchronization instruction input is set to operation selection exception, the synchronization instruction output is mode selection fault.

[0026] Further, when the real-time state of the synchronization shaft is pinching, if the controller synchronization instruction input is set to lifting point 1 single-action or lifting point 2 single-action, the synchronization instruction output is mode selection fault, if the controller synchronization instruction input is set to electrical synchronization operation, the synchronization instruction output is mode selection fault, if the controller synchronization instruction input is set to mechanical synchronization operation, the synchronization instruction output is mechanical synchronization operation, and if the controller synchronization instruction input is set to operation selection exception, the synchronization instruction output is mode selection fault.

[0027] Further, when the real-time state of the synchronous shaft is the intermediate abnormal position, if the controller synchronization instruction input is set as the single action of the lifting point 1 or the single action of the lifting point 2, the synchronization instruction output is the synchronous shaft fault, if the controller synchronization instruction input is set as the electrical synchronization operation, the synchronization instruction output is the synchronous shaft fault, if the controller synchronization instruction input is set as the mechanical synchronization operation, the synchronization instruction output is the synchronous shaft fault, and if the controller synchronization instruction input is set as the mode selection exception, the synchronization instruction output is the synchronous shaft fault.

[0028] Further, in step e, when the controller synchronization instruction output is the single action of the lifting point 1 or the single action of the lifting point 2, the controller controls the frequency converter of the corresponding lifting point to access the corresponding lifting motor, so as to realize the running or stopping control of the lifting motor of the lifting point.

[0029] When the controller synchronization instruction output is the electrical synchronization operation, the controller controls the frequency converters of the two lifting points to access the corresponding lifting motors, so as to realize the running control of the lifting motors of the two lifting points, and the controller obtains the position difference between the lifting point 1 and the lifting point 2 in real time through the position sensor, so as to compare the speed synchronization of the lifting point 1 and the lifting point 2, adjust the running speed of the lifting point through the program logic judgment, and thus realize the electrical synchronization operation of the double-lifting-point lifting mechanism.

[0030] When the controller synchronization instruction output is the mechanical synchronization operation, the controller controls the lifting motor of the lifting point 1 to run, and the internal components of the frequency converter of the lifting point 1 and the frequency converter of the lifting point 2 form a master-slave torque control, the frequency converter of the lifting point 1 sends the real-time torque value to the frequency converter of the lifting point 2 through the signal cable, the frequency converter of the lifting point 2 outputs the same torque signal, and the torque signal is accessed to the lifting motor of the lifting point 2 through the power cable, so as to realize the mechanical synchronization control of the double-lifting-point lifting mechanism.

[0031] When the controller synchronization instruction output is the synchronous shaft fault or the mode selection fault, the controller controls the lifting motors of the lifting point 1 and the lifting point 2 to stop running.

[0032] In summary, the present application has the following advantages:

[0033] 1. The present application adopts the machine vision technology to detect the real-time position of the clutch, judges the separation and pinch state of the synchronous shaft, intelligently identifies the compliance and safety of the state of the synchronous shaft in combination with the system synchronization instruction input signal, outputs the synchronization control mode in the normal state of the synchronous shaft, and the system can normally run; in the abnormal state of the synchronous shaft, the synchronous shaft fault and the shutdown instruction are outputted, and the system immediately stops running, so that the running safety risk caused by the abnormal state of the synchronous shaft can be effectively avoided.

[0034] 2、The clutch position is recognized by combining the SIFT algorithm, and the minimum enclosing rectangle and the inclination angle of the clutch are obtained by combining pretreatment methods such as gray scale conversion, edge detection and contour screening, the inclination angle is combined with the calibration parameter to judge the working state of the clutch, and a relatively accurate state judgment result can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a schematic diagram of the overall arrangement of the visual detection system of the application.

[0036] Figure 2 It is a technical roadmap of the method of the application.

[0037] Figure 3 It is a schematic diagram of the inclination angle of the clutch of the application.

[0038] In the figure:

[0039] 1, visual camera; 2, light source; 3, support; 4, clutch; 5, synchronous shaft; 6, lifting motor. DETAILED DESCRIPTION

[0040] In order to more clearly illustrate the application, the application will be further described below in combination with preferred embodiments and drawings. Those skilled in the art should understand that the specific description below is illustrative rather than limiting, and should not limit the protection scope of the application.

[0041] The application provides a crane double-hoisting-point synchronous control method based on machine vision detection, referring to the technical roadmap as shown in Figure 2 , including the following steps:

[0042] Step a, system power-on, the visual analysis software installed in the industrial control computer performs self-checking on the visual camera and the light source, and after successful self-checking, the next step is performed, if the self-checking fails, the industrial control computer sends a fault to the controller (PLC), and the controller (PLC) controls the system to stop running.

[0043] As shown in Figure 1 , it is a schematic diagram of the overall arrangement of the visual detection system, which includes a synchronous shaft, a clutch, a visual camera, a light source, a support, a signal cable, a power cable, an industrial control computer, a controller (PLC), a synchronous mode knob switch, a hoisting point knob switch, a frequency converter, a lifting motor, a position sensor, etc.

[0044] Wherein, the visual camera and the light source are installed on the support, the support is welded near the clutch, the light source is connected to the visual camera through the signal cable, the visual camera is connected to the industrial control computer through the signal cable, the industrial control computer is connected to the controller (PLC) through the signal cable, the controller (PLC) is connected to the frequency converter through the signal cable, the frequency converter is connected to the lifting motor through the power cable, the synchronous mode knob switch is connected to the controller (PLC) through the signal cable, the lifting point knob switch is connected to the controller (PLC) through the signal cable, the lifting point 1 frequency converter is connected to the lifting point 2 frequency converter through the signal cable, and the height sensor is installed on the lifting mechanism equipment and connected to the controller (PLC) through the signal cable.

[0045] Step b, the visual camera and the light source work at the same time, and the clutch position photo is captured, and the photo is transmitted into the industrial control computer visual analysis software through the signal cable.

[0046] In this step, the camera is erected in the direction of the clutch, and the imaging plane of the camera is kept level with the horizontal plane, and the clutch area image is captured by the camera.

[0047] Step c, the visual analysis software calculates the clutch position according to the clutch deep learning training algorithm, judges the state of the synchronous shaft belonging to one of the separated, pinched and intermediate abnormal positions, and the industrial control computer sends the real-time state information of the synchronous shaft to the controller (PLC) through the signal cable.

[0048] In this embodiment, the visual analysis software obtains the position of the clutch through the SIFT algorithm, and obtains the minimum enclosing rectangle of the clutch after preprocessing such as gray scale conversion, edge detection and contour screening, and calculates the inclination angle of the central axis of the rectangle and the horizontal line, as shown in the formula (1). Figure 3 Further, the working state of the clutch is judged according to the angle and the calibration parameter.

[0049] SIFT (Scale Invariant Feature Transform, Scale Invariant Feature Transform Matching Algorithm) is a high-efficiency region detection algorithm, which can be applied to object recognition, robot map perception and navigation, image stitching, 3D model establishment, gesture recognition, image tracking and motion comparison, etc. It has the advantages of stability, uniqueness, multi-quantity, high speed, scalability, etc., and can solve the problems caused by rotation, scaling, translation, image radiation / projection transformation of the target, and still has good detection effect under the influence of light, partial target shielding and debris, noise scene. The SIFT algorithm can be divided into the following steps:

[0050] 1) Scale space extreme value detection: search for all image positions in all scales. Identify potential interest points that are invariant to scale and rotation through a Gaussian differential function.

[0051] 2) Accurate keypoint localization: At each candidate location, a refined model is fit to determine the position and scale. The choice of keypoints is based on their stability.

[0052] 3) Assigning dominant orientation to keypoints: Based on the local image gradient direction, one or more orientations are assigned to each keypoint location. All subsequent operations on the image data are transformed relative to the orientation, scale and position of the keypoints, thus providing invariance to these transformations.

[0053] 4) Generating the SIFT feature vector (keypoint descriptor): Within a neighborhood around each keypoint, the local image gradients are measured at the selected scale. These gradients are transformed into a representation that allows comparison of large local shape variations and illumination changes.

[0054] By extracting the scale-invariant feature transform feature points in the clutch image, a feature matrix is generated. By calling a pre-trained classification model including the clutch area and the non-clutch area, the classification model is obtained based on the scale-invariant feature transform feature points of a plurality of clutch areas and a plurality of non-clutch areas, and the clutch position can be determined according to the feature point matrix by using the classification model.

[0055] Edge detection is mainly through some means to detect the digital image in the light and dark changes (i.e. gradient change is larger) pixel point, biased to the change of pixel points in the image, the result is usually saved in the same size and type of edge map as the source picture. In the embodiment, Canny edge detection is used, and the Canny algorithm proposes non-maximum suppression based on edge gradient direction and double threshold hysteresis threshold processing. In the embodiment, the processing steps of the Canny algorithm are as follows:

[0056] 1) Gaussian smoothing is performed on the input image to reduce the error rate;

[0057] 2) Calculate the gradient amplitude and direction to estimate the edge strength and direction at each point;

[0058] 3) According to the gradient direction, the non-maximum suppression is performed on the gradient amplitude;

[0059] 4) Use double threshold processing and connect the edges.

[0060] Contour can be simply considered as a curve that connects the continuous points (connected boundary) together, with the same color or gray level. Contour is the external feature of the image target, and this feature has great significance for image analysis, target recognition and understanding and other deeper processing.

[0061] Contour detection refers to detecting the object boundary in the image, and is more inclined to focus on the upper semantic object. For example, the findContours() function in OpenCV can obtain each contour and store it in the form of a point vector, and also obtain the topological information of an image, i.e., the index number of the next contour, the previous contour, etc.

[0062] The basic principle of contour extraction is: for a binary image with black background and white target, if a white point is found in the image, and its 8-neighborhood (or 4-neighborhood) is also white, it means that the point is an internal point of the target, and it is set to black, which is visually like the internal part is hollowed out; otherwise, the white point remains unchanged, which is a contour point of the target. Generally, before finding the contour, the image is thresholded or Canny edge detection is performed to convert it into a binary image.

[0063] Minimum enclosing rectangle and rotation angle: after obtaining the object contour, the minAreaRect() function can be used to obtain the minimum enclosing rectangle of the contour, and the RotatedRect obtained has three attributes: 1) the center point (centroid) of the rectangle; 2) the side length (length and width); 3) the rotation angle (the returned value is the angle value, not the radian value). The rotation angle can be obtained by calling the angle attribute, so that the working state of the clutch can be determined according to the angle.

[0064] The SIFT algorithm and the classification model can accurately identify the position of the clutch on the image, and the minimum enclosing rectangle and the tilt angle of the clutch can be obtained by combining the preprocessing methods such as gray scale conversion, edge detection, and contour screening. According to the tilt angle and the calibration parameters, the working state of the clutch can be determined, and a more accurate discrimination result can be obtained.

[0065] Step d, after the controller (PLC) receives the real-time state information of the synchronous shaft transmitted by the industrial control computer through the signal cable, the real-time comparison is made with the synchronous instruction input setting information, the compliance and safety of the synchronous shaft state and the synchronous instruction input setting are identified, and the corresponding control strategy is made.

[0066] Specifically, in this step, when the real-time state of the synchronous shaft is separated, the controller (PLC) is set to single operation of lifting point 1, and the synchronous instruction output is single operation of lifting point 1.

[0067] When the real-time state of the synchronous shaft is separated, the controller (PLC) is set to single operation of lifting point 2, and the synchronous instruction output is single operation of lifting point 2.

[0068] When the real-time state of the synchronous shaft is separated, the controller (PLC) is set to electrical synchronization selection, and the synchronous instruction output is electrical synchronization operation.

[0069] When the real-time state of the synchronous shaft is split, the controller (PLC) synchronization instruction input is set to mechanical synchronization selection, and the synchronization instruction output is mode selection failure.

[0070] When the real-time state of the synchronous shaft is split, the controller (PLC) synchronization instruction input is set to job selection exception, and the synchronization instruction output is mode selection failure.

[0071] When the real-time state of the synchronous shaft is kneading, the controller (PLC) synchronization instruction input is set to single job of lifting point 1, and the synchronization instruction output is mode selection failure.

[0072] When the real-time state of the synchronous shaft is kneading, the controller (PLC) synchronization instruction input is set to single job of lifting point 2, and the synchronization instruction output is mode selection failure.

[0073] When the real-time state of the synchronous shaft is kneading, the controller (PLC) synchronization instruction input is set to electrical synchronization job, and the synchronization instruction output is mode selection failure.

[0074] When the real-time state of the synchronous shaft is kneading, the controller (PLC) synchronization instruction input is set to mechanical synchronization job, and the synchronization instruction output is mechanical synchronization operation.

[0075] When the real-time state of the synchronous shaft is kneading, the controller (PLC) synchronization instruction input is set to job selection exception, and the synchronization instruction output is mode selection failure.

[0076] When the real-time state of the synchronous shaft is intermediate abnormal position, the controller (PLC) synchronization instruction input is set to single job of lifting point 1, and the synchronization instruction output is synchronous shaft failure.

[0077] When the real-time state of the synchronous shaft is intermediate abnormal position, the controller (PLC) synchronization instruction input is set to single job of lifting point 2, and the synchronization instruction output is synchronous shaft failure.

[0078] When the real-time state of the synchronous shaft is intermediate abnormal position, the controller (PLC) synchronization instruction input is set to electrical synchronization job, and the synchronization instruction output is synchronous shaft failure.

[0079] When the real-time state of the synchronous shaft is intermediate abnormal position, the controller (PLC) synchronization instruction input is set to mechanical synchronization job, and the synchronization instruction output is synchronous shaft failure.

[0080] When the real-time state of the synchronous shaft is intermediate abnormal position, the controller (PLC) synchronization instruction input is set to mode selection exception, and the synchronization instruction output is synchronous shaft failure.

[0081] Step e, after the controller (PLC) judges the synchronization instruction output signal, the frequency converter control word is generated and sent to the frequency converter through the signal cable. The frequency converter controls the start and stop of the lifting motor according to different control words to realize the synchronization control of the crane under different operations:

[0082] When the controller (PLC) synchronization instruction output is the single operation of the lifting point 1, the controller (PLC) generates the lifting point 1 frequency converter running control word, which is sent to the lifting point 1 frequency converter through the signal cable. The frequency converter outputs the running frequency according to the running control word, which is connected to the lifting point 1 lifting motor through the power cable to realize the running control of the lifting point 1 lifting motor.

[0083] The controller (PLC) generates the lifting point 2 frequency converter stop control word, which is sent to the lifting point 2 frequency converter through the signal cable. The frequency converter outputs zero frequency according to the stop control word, which is connected to the lifting point 2 lifting motor through the power cable to realize the stop control of the lifting point 2 lifting motor. In this way, the single operation of the lifting point 1 is realized.

[0084] When the controller (PLC) synchronization instruction output is the single operation of the lifting point 2, the controller (PLC) generates the lifting point 2 frequency converter running control word, which is sent to the lifting point 2 frequency converter through the signal cable. The frequency converter outputs the running frequency according to the running control word, which is connected to the lifting point 2 lifting motor through the power cable to realize the running control of the lifting point 2 lifting motor. The controller (PLC) generates the lifting point 1 frequency converter stop control word, which is sent to the lifting point 1 frequency converter through the signal cable. The frequency converter outputs zero frequency according to the stop control word, which is connected to the lifting point 1 lifting motor through the power cable to realize the stop control of the lifting point 1 lifting motor. In this way, the single operation of the lifting point 2 is realized.

[0085] When the controller (PLC) synchronous instruction output is electrical synchronization operation, the controller (PLC) generates the running control word of the hoisting point 1 frequency converter, sends it to the hoisting point 1 frequency converter through the signal cable, the frequency converter outputs the running frequency according to the running control word, and the power cable is connected to the hoisting point 1 hoisting motor to realize the running control of the hoisting point 1 hoisting motor. The controller (PLC) generates the running control word of the hoisting point 2 frequency converter, sends it to the hoisting point 2 frequency converter through the signal cable, the frequency converter outputs the running frequency according to the running control word, and the power cable is connected to the hoisting point 2 hoisting motor to realize the running control of the hoisting point 2 hoisting motor. The position sensors are installed on the hoisting point 1 and the hoisting point 2, the controller (PLC) calculates the position difference of the hoisting point 1 and the hoisting point 2 in real time, and compares the speed synchronization of the hoisting point 1 and the hoisting point 2. When the running speed of the hoisting point 1 is slow or the running speed of the hoisting point 2 is fast, the controller (PLC) appropriately increases the output running frequency of the hoisting point 1 frequency converter or appropriately reduces the output running frequency of the hoisting point 2 frequency converter. When the running speed of the hoisting point 1 is fast or the running speed of the hoisting point 2 is slow, the controller (PLC) appropriately reduces the output running frequency of the hoisting point 1 frequency converter or appropriately increases the output running frequency of the hoisting point 2 frequency converter. When the position difference between the hoisting point 1 and the hoisting point 2 is small, the output running frequency of the hoisting point 1 frequency converter and the output running frequency of the hoisting point 2 frequency converter are not adjusted. In this way, the electrical synchronization operation of the double-hoisting point hoisting mechanism is realized.

[0086] When the controller (PLC) synchronous instruction output is mechanical synchronization operation, the controller (PLC) generates the running control word of the hoisting point 1 frequency converter, sends it to the hoisting point 1 frequency converter through the signal cable, the frequency converter outputs the running frequency according to the running control word, and the power cable is connected to the hoisting point 1 hoisting motor to realize the running control of the hoisting point 1 hoisting motor. The master-slave torque control is internally composed between the hoisting point 1 frequency converter and the hoisting point 2 frequency converter. The hoisting point 1 frequency converter is connected to the hoisting point 2 frequency converter through the signal cable, the hoisting point 1 frequency converter sends the real-time torque value to the hoisting point 2 frequency converter, the hoisting point 2 frequency converter outputs the same torque signal, and the power cable is connected to the hoisting point 2 hoisting motor to realize the mechanical synchronization control of the double-hoisting point hoisting mechanism.

[0087] When the controller (PLC) synchronous instruction output is mode selection fault, the controller (PLC) generates the stop control word of the hoisting point 1 frequency converter, sends it to the hoisting point 1 frequency converter through the signal cable, the frequency converter sets the output frequency to zero according to the stop control word, and the power cable is connected to the hoisting point 1 hoisting motor to realize the stop control of the hoisting point 1 hoisting motor. The controller (PLC) generates the stop control word of the hoisting point 2 frequency converter, sends it to the hoisting point 2 frequency converter through the signal cable, the frequency converter sets the output frequency to zero according to the stop control word, and the power cable is connected to the hoisting point 2 hoisting motor to realize the stop control of the hoisting point 2 hoisting motor.

[0088] When the controller (PLC) synchronizes the instruction output as a synchronous shaft fault, the controller (PLC) generates a suspension point 1 frequency converter stop control word, which is sent to the suspension point 1 frequency converter through a signal cable. The frequency converter sets the output frequency to zero according to the stop control word, and connects the suspension point 1 lifting motor through the power cable to realize the suspension point 1 lifting motor stop control. The controller (PLC) generates a suspension point 2 frequency converter stop control word, which is sent to the suspension point 2 frequency converter through a signal cable. The frequency converter sets the output frequency to zero according to the stop control word, and connects the suspension point 2 lifting motor through the power cable to realize the suspension point 2 lifting motor stop control.

[0089] The present application adopts machine vision technology to detect the real-time position of the clutch, judges the separation and pinch state of the synchronous shaft, combines the system synchronization instruction input signal, intelligently identifies the compliance and safety of the synchronous shaft state, outputs the synchronous control mode under the normal state of the synchronous shaft, and the system can normally operate. The synchronous shaft fault and shutdown instruction are output under the abnormal state of the synchronous shaft, and the system immediately stops running, so that the running safety risk caused by the abnormal state of the synchronous shaft can be effectively avoided.

[0090] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification or equivalent change made according to the technical essence of the present application to the above embodiment falls within the protection scope of the present application.

Claims

1. A method for synchronous control of dual lifting points of a crane based on machine vision inspection, characterized in that, Includes the following steps: Step a: Use the vision analysis software installed in the industrial control computer to perform a self-test on the vision camera and light source installed near the clutch. After the self-test is successful, proceed to the next step. Step b: The vision camera and light source work simultaneously to capture a photo of the clutch position and then transfer the photo to the industrial control computer vision analysis software. Step c: The visual analysis software obtains the clutch position based on the clutch deep learning training algorithm, and in combination with the calibration parameters, determines whether the synchronous shaft is in a state of separation, engagement, or abnormal intermediate position, and sends the real-time status information of the synchronous shaft to the controller through the industrial control computer. Step d: After receiving the real-time status information of the synchronous shaft, the controller compares it with the synchronous command input setting information in real time to identify the conformity and safety of the synchronous shaft status with the synchronous command input setting, and makes corresponding control strategies. Step e: After the controller internally judges the output signal of the synchronization command, it generates the frequency converter control word and sends it to the frequency converter. The frequency converter controls the start and stop of the hoisting motor according to different control words to realize the synchronous control of the crane under different operations. In step c, the visual analysis software identifies the clutch position using the SIFT algorithm. After preprocessing through grayscale conversion, edge detection, and contour filtering, the minimum bounding rectangle of the clutch is obtained. The tilt angle between the central axis of the rectangle and the horizontal line is calculated, and the working state of the clutch is determined based on the angle. In step d, the synchronous mode rotary switch is connected to the controller via a signal cable. The controller receives one of the input modes selected by the synchronous mode rotary switch: single hook operation, electrical synchronous operation, and mechanical synchronous operation. The lifting point rotary switch is connected to the controller via a signal cable. The controller receives one of the input modes selected by the lifting point rotary switch: single action of lifting point 1, single action of lifting point 2, and linkage of double lifting points. When the synchronous mode knob switch input is single hook operation, if the lifting point knob switch input is lifting point 1 single action mode or lifting point 2 single action mode, then the synchronous command input on the controller is set to lifting point 1 single action operation or lifting point 2 single action operation accordingly. If the lifting point knob switch is in dual lifting point linkage mode, then the synchronous command input on the controller is set to operation selection abnormal. When the synchronous mode knob switch is in electrical synchronous operation, if the lifting point knob switch is in lifting point 1 single-action mode or lifting point 2 single-action mode, the synchronous command input on the controller is set to operation selection abnormal. If the lifting point knob switch is in dual lifting point linkage mode, the synchronous command input on the controller is set to electrical synchronous operation. When the synchronization mode knob switch is set to mechanical synchronization operation, if the lifting point knob switch is set to lifting point 1 single-action mode or lifting point 2 single-action mode, the synchronization command input on the controller is set to operation selection abnormal. If the lifting point knob switch is set to dual lifting point linkage mode, the synchronization command input on the controller is set to mechanical synchronization operation.

2. The crane dual-lifting-point synchronous control method based on machine vision inspection as described in claim 1, characterized in that, In step b, a camera is set up in the direction of the clutch, ensuring that the camera's imaging plane is level with the horizontal plane, and the camera captures an image of the clutch area.

3. The crane dual-lifting-point synchronous control method based on machine vision inspection as described in claim 1, characterized in that, Edge detection is implemented using the Canny algorithm, and the steps include: 1) Apply Gaussian smoothing to the input image to reduce the error rate; 2) Calculate the gradient magnitude and direction to estimate the edge strength and direction at each point; 3) Based on the gradient direction, perform non-maximum suppression on the gradient magnitude; 4) Use double thresholding to process and connect edges, and save the results to an edge map of the same size and type as the source image.

4. The crane dual-lifting-point synchronous control method based on machine vision inspection as described in claim 1, characterized in that, After performing contour filtering, the minAreaRect() function is used to obtain the smallest bounding rectangle that covers the contour. This smallest bounding rectangle has three attributes: 1) the center point of the rectangle, i.e., the centroid; 2) the side length, including the length and width; 3) the angle value; the angle attribute is called to obtain the rotation angle, which is the tilt angle between the central axis of the rectangle and the horizontal line.

5. The crane dual-lifting-point synchronous control method based on machine vision inspection as described in claim 1, characterized in that, When the real-time status of the synchronous shaft is separated, if the controller synchronization command input is set to single-action operation of lifting point 1 or single-action operation of lifting point 2, the corresponding synchronization command output will be single-action operation of lifting point 1 or single-action operation of lifting point 2. If the controller synchronization command input is set to electrical synchronization selection, the synchronization command output will be electrical synchronization operation. If the controller synchronization command input is set to mechanical synchronization selection, the synchronization command output will be mode selection fault. If the controller synchronization command input is set to operation selection abnormality, the synchronization command output will be mode selection fault.

6. The crane dual-lifting-point synchronous control method based on machine vision inspection as described in claim 5, characterized in that, When the real-time status of the synchronous shaft is pinched, if the controller synchronization command input is set to single-action operation of lifting point 1 or single-action operation of lifting point 2, the synchronization command output will be a mode selection fault. If the controller synchronization command input is set to electrical synchronization operation, the synchronization command output will be a mode selection fault. If the controller synchronization command input is set to mechanical synchronization operation, the synchronization command output will be mechanical synchronization operation. If the controller synchronization command input is set to operation selection abnormality, the synchronization command output will be a mode selection fault.

7. The crane dual-lifting-point synchronous control method based on machine vision inspection as described in claim 6, characterized in that, When the real-time status of the synchronous shaft is in the intermediate abnormal position, if the controller synchronization command input is set to single-action operation of lifting point 1 or single-action operation of lifting point 2, the synchronization command output will be a synchronous shaft fault. If the controller synchronization command input is set to electrical synchronization operation, the synchronization command output will be a synchronous shaft fault. If the controller synchronization command input is set to mechanical synchronization operation, the synchronization command output will be a synchronous shaft fault. If the controller synchronization command input is set to mode selection abnormality, the synchronization command output will be a synchronous shaft fault.

8. The crane dual-lifting-point synchronous control method based on machine vision inspection as described in claim 7, characterized in that, In step e, when the controller's synchronization command output indicates that lifting point 1 or lifting point 2 is operating independently, the controller controls the frequency converter of the corresponding lifting point to connect to the corresponding hoisting motor, thereby realizing the operation or stop control of the hoisting motor at that lifting point. When the controller outputs the synchronization command for electrical synchronization, the controller controls the frequency converters of the two lifting points to connect to the corresponding lifting motors, thereby achieving the operation control of the lifting motors of the two lifting points. The controller obtains the position difference between lifting point 1 and lifting point 2 in real time through the position sensor, compares the speed synchronization between lifting point 1 and lifting point 2, and adjusts the running speed of the lifting points through program logic judgment, thereby achieving the electrical synchronization of the dual-lifting-point lifting mechanism. When the controller's synchronization command output is mechanically synchronized, the controller controls the hoisting motor of lifting point 1 to run. The inverters of lifting point 1 and lifting point 2 form a master-slave torque control internally. The inverter of lifting point 1 sends the real-time torque value to the inverter of lifting point 2 through the signal cable. The inverter of lifting point 2 outputs the same torque signal, which is connected to the hoisting motor of lifting point 2 through the power cable, thereby realizing the mechanical synchronization control of the dual-lifting-point mechanism. When the controller outputs a synchronization command indicating a synchronous shaft fault or a mode selection fault, the controller stops the lifting motors at lifting points 1 and 2.

Images