A method and system for protecting a grab bucket of an automated door machine from being hung or crushed

Abstract

The application provides a kind of automatic gate machine grab cabin, and a kind of protection method of cabin, comprising the following steps: by camera, the video stream of grab and ship hatch is obtained, and the pixel coordinates of grab and ship hatch in image are identified and acquired in real time;Calculate the minimum pixel distance of grab and ship hatch in image, and convert the minimum pixel distance into physical distance according to pixel equivalent;Real-time motion state parameters and external working condition parameters of gate machine lifting mechanism, luffing mechanism and rotating mechanism are obtained, and the real-time stop distance of the three mechanisms under the current working condition is obtained, then the comprehensive stop distance is obtained through three-dimensional space synthesis model, and finally the safety threshold is obtained by combining safety factor and working condition correction coefficient;Compare the physical distance with the safety threshold, when the physical distance between grab and ship hatch is less than the safety threshold, execute cabin hanging or cabin breaking protection alarm, and trigger gate brake control.

Description

Technical Field

[0001] This invention relates to the field of port gantry crane technology, and in particular to an automated gantry crane grab bucket protection method and system for preventing gantry crane grab bucket from being attached to or crushed into a hold. Background Technology

[0002] Gantry cranes are important loading and unloading equipment in bulk cargo ports. Their main motion mechanisms include luffing mechanism, slewing mechanism, hoisting mechanism, and traveling mechanism. By combining hoisting, luffing, and slewing movements, objects can be moved within a circular cylindrical space, and the traveling mechanism enables the movement of the trolley.

[0003] In the field of automated port gantry crane operations, during the automated loading and unloading process of bulk cargo ships, safety issues may arise due to factors such as incorrect path planning, incomplete point cloud models of the cargo hold, and deviations in the motion control of the mechanism. These issues can lead to grab buckets getting caught on hatches (hooked onto the hold) or hitting the edge of the hatch (hit on the hold). Existing solutions do not provide real-time warnings of the safe distance between the grab bucket and the hatch, which can easily lead to safety accidents.

[0004] Therefore, a method and system for protecting the grab bucket from being attached to or crushed in an automated gantry crane are proposed to solve the safety problems of grab bucket attachment and crushing during the automation of the gantry crane, so as to improve the safety of gantry crane operation. Summary of the Invention

[0005] In view of this, the present invention proposes an automated gantry crane grab bucket hanging and cabin crushing protection method and system to solve the safety problems of grab bucket hanging and cabin crushing during the automation of gantry cranes, so as to improve the safety of gantry crane operation.

[0006] This invention proposes an automated gantry crane grab bucket protection method and system for preventing grab bucket from being attached to or crushed, which solves the technical problem of dangerous swaying of the grab bucket due to excessive deceleration during emergency braking, thus ensuring smooth braking of the grab bucket.

[0007] This invention proposes an automated gantry crane grab bucket loading and hull-breaking protection method and system, which solves the technical problems of target identification confusion, spatial interference detection and lack of coordinated control in existing dual gantry crane shared hull operations.

[0008] This invention proposes an automated gantry crane grab bucket protection method for preventing hull hanging and hull crushing, comprising the following steps: The video streams of the grab bucket and the hatch are obtained by the camera, and the pixel coordinates of the grab bucket and the hatch in the image are identified and obtained in real time. The pixel coordinates of the grab are converted into normalized planar coordinates, and the position of the grab is projected onto the height plane of the hatch to obtain normalized pixel coordinates. Calculate the minimum pixel distance between the grab and the hatch in the image, and convert the minimum pixel distance into a physical distance based on pixel equivalents; The real-time motion state parameters and external working condition parameters of the gantry crane hoisting mechanism, luffing mechanism and slewing mechanism are obtained to obtain the real-time stopping distance of the three mechanisms under the current working condition. The comprehensive stopping distance is then obtained through a three-dimensional spatial synthesis model. Finally, the safety threshold is obtained by combining the safety factor and the working condition correction factor. The physical distance is compared with the safety threshold. When the physical distance between the grab bucket and the hatch is less than the safety threshold, a hatch attachment or crash protection alarm is triggered, and the door mechanism braking control is activated.

[0009] Based on the above technical solution, preferably, the calculation of the safety threshold includes: calculating the stopping distance in the lifting direction, the stopping distance in the luffing direction, and the stopping distance in the rotation direction respectively, and using a three-dimensional spatial synthesis model to calculate the comprehensive stopping distance.

[0010] Based on the above technical solution, preferably, the braking control introduces a swing angle safety constraint, including setting a maximum allowable swing angle and calculating the maximum allowable horizontal deceleration according to the pendulum dynamics model, so as to prevent the grab bucket from swinging dangerously relative to the hoist through the steel cable due to excessive braking.

[0011] Based on the above technical solutions, a preferred embodiment also includes sway suppression for braking in the lifting direction: the maximum permissible lifting deceleration is calculated based on the elastic modulus, cross-sectional area, and suspension length of the steel cable.

[0012] Based on the above technical solutions, a preferred option also includes a shared-cabin operation mode, including: The pixel coordinates acquired by the two gantry cameras are uniformly mapped to the global coordinate system through perspective transformation; Calculate and compare the spatial interference distance D12 between the main grab M1 and the slave grab M2 and the co-cabin interference safety distance D_safe in the global coordinate system to determine whether there is a risk of dual-machine interference.

[0013] Based on the above technical solution, preferably, the shared cabin operation mode adds shared cabin-specific constraints: overlapping area mutual exclusion constraint: only one grab bucket is allowed to enter the vertical projection overlapping area of ​​the hatch at the same time; height interlock constraint: two grab buckets are not allowed to be lower than the preset safe height at the same time; descent sequence control constraint: the principle of first-come, first-served is adopted, and the gantry crane that applies later enters the waiting queue; when any constraint is violated, the grab bucket descent action is immediately stopped, the movement of the two gantry cranes toward the hatch is locked, and the operation is resumed according to the application sequence after the overlapping area is cleared.

[0014] Based on the above technical solutions, the preferred approach is to incorporate an overlap area coefficient, an interference risk coefficient, and a dual-machine synchronization coefficient into the dynamic safety threshold calculation for shared cabin operations, thereby achieving dynamic and adaptive calculation of the shared cabin safety threshold.

[0015] Based on the above technical solution, preferably, the minimum pixel distance is calculated as follows: when the grab is a two-lobed grab, the minimum pixel distance between the grab and the hatch is obtained by calculating the minimum distance between the two polygons; when the grab is a six-lobed grab, the minimum pixel distance between the grab and the hatch is obtained by calculating the minimum distance between the circle and the polygon.

[0016] Based on the above technical solution, preferably, the working condition correction coefficient includes a wind condition correction coefficient, a material weight correction coefficient, and a mechanism wear correction coefficient.

[0017] On the other hand, the present invention also provides an automated gantry crane grab bucket hanger and hanger crush protection system, which applies the aforementioned protection method, including: Self-stabilizing camera, mounted on the gantry crane's trunk platform; The image processing module is used to perform deep learning object detection and image segmentation; The distance calculation module is used to perform pixel coordinate transformation, projection transformation, and physical distance calculation. The dynamic safety threshold calculation module is used to calculate the final safety threshold based on the mechanism's motion state, operating parameters, and swing angle constraints. The alarm and braking control module is used to trigger graded alarms and perform graded braking with swing angle limits.

[0018] The present invention provides an automated gantry crane grab bucket hanging and crush protection method and system, which, compared with the prior art, has the following advantages: (1) Based on deep learning-based target detection and image segmentation, combined with pinhole imaging projection transformation, the physical distance between the grab bucket and the hatch can be calculated in real time and accurately, without being affected by the incomplete point cloud of the hatch. The dynamic safety threshold comprehensively considers the actual working conditions such as the motion state of the three mechanisms, load, wind speed, and wear, avoiding false alarms or missed alarms caused by fixed thresholds; (2) Introducing swing angle safety constraints and graded braking model effectively suppresses grab bucket swing caused by emergency stop, prevents secondary collisions, steel cable derailment and other risks, and improves braking safety; (3) The local pixel coordinates of the two machines are unified into the global coordinate system through perspective transformation, eliminating the coordinate deviation caused by different perspectives and providing a unified benchmark for the interference calculation of the two machines; the spatial interference distance and the safe distance of the shared compartment are defined; the collision risk of the two machines can be calculated and compared in real time, and the system has the protection capability of shared compartment operation, which can meet the port efficiency improvement needs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a flowchart illustrating the process of an automated gantry crane grab bucket hanging and crush protection method and system according to the present invention. Figure 2 This is a schematic diagram of the structure of an automated door operator according to the present invention; Figure 3 This is a diagram showing the two-lobed grab and the six-lobed circular grab of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0027] The technical solution is explained in detail. Currently, during the automated loading and unloading process of bulk cargo holds, safety issues may arise due to factors such as incorrect path planning, incomplete point cloud models of the holds, and deviations in the motion control of the mechanisms. These issues may lead to the grab bucket getting caught on the hatch (hooked on the hold) or hitting the edge of the hatch (hit on the hold). The existing solution does not provide real-time warnings of the safe distance between the grab bucket and the hatch, which can easily lead to safety accidents.

[0028] In view of this, such as Figure 1 As shown, the present invention provides a method for protecting the grab bucket of an automated gantry crane from being attached to or crushed by the hull, comprising the following steps: Step S1: Obtain video streams of the grab bucket and hatch through the camera, and identify and acquire the pixel coordinates of the grab bucket and hatch in the image in real time; Specifically, a self-stabilizing camera is installed on the gantry crane's trunk platform. When the grab bucket finishes grabbing material inside the hold and begins to lift, it receives a hold protection detection command. When the grab bucket reaches a safe height, the hold protection detection command ends. When the grab bucket finishes unloading material and begins to descend back into the hold, it receives a hold-slamming protection detection command. When the grab bucket enters the hold, the hold-slamming protection detection command ends.

[0029] Upon receiving the detection command, the system connects to the camera and begins real-time image acquisition. It then uses a deep learning-based object detection model with a rotating bounding box to infer the pixel coordinates of the grab bucket within the image. Finally, it uses a deep learning-based image segmentation model to infer the pixel coordinates of the hatch within the image.

[0030] Step S2: Convert the pixel coordinates of the grab bucket to normalized planar coordinates, and project the position of the grab bucket onto the height plane of the hatch to obtain the normalized pixel coordinates. When the grab is a two-lobed grab, the rectangular bounding box of the grab in the image is directly inferred from the object detection model to determine its position. When the grab is a six-lobed circular grab, image post-processing is used to obtain a circle with the center of the object detection box as its center point and the side length of the detection box as its diameter, thus obtaining the position of the six-lobed grab in the image. Since the edges of the hatch image obtained by the image segmentation model are irregular, post-processing is performed using contour approximation, area and rectangle judgment, etc. Finally, the four corner points of the hatch are obtained by using the minimum bounding rectangle.

[0031] Step S3: Calculate the minimum pixel distance between the grab bucket and the hatch in the image, and convert the minimum pixel distance into physical distance based on pixel equivalent; Specifically, the relationship between the distance from the object to the camera and the pixel equivalent is determined. Based on the ranging method using the pinhole imaging principle, the relationship between the pixel equivalent and the distance from the camera to the object can be obtained:

[0032]

[0033] In the formula: f: focal length (unit: pixels); d: distance between camera and object (unit: meters); x: image length of object (unit: pixels); w: physical length of object (unit: meters); p: pixel equivalent.

[0034] Since the camera's focal length is constant, the pixel equivalent is directly proportional to the distance between the camera and the object. The camera's focal length can be obtained through camera calibration, while the distances from the camera to the grab bucket and from the camera to the hatch can be measured using sensors.

[0035] Because the distances between the grab and the camera differ from those between the hatch and the camera, the pixel equivalents corresponding to the grab height and the hatch height are different. First, the pixel coordinates of the four corner points of the grab are converted to normalized planar coordinates. Then, the position of the grab is projected onto the height plane of the hatch to obtain new grab pixel coordinates, which are then converted to normalized coordinates, scaled according to the height ratio, and finally converted back to pixel coordinates.

[0036] Original pixel coordinates (u, v) converted to normalized coordinates:

[0037] New normalized coordinates (after scaling):

[0038] Normalized pixel coordinates:

[0039] ( , ):focal length;( , ): Main point; The distance from the camera to the grab bucket; This is the distance from the camera to the hatch.

[0040] The intrinsic parameter matrix can be obtained through camera calibration. This allows us to obtain the camera's focal length and principal point.

[0041] Finally, the minimum pixel distance between the grab bucket and the hatch in the image is calculated. When the grab bucket is a two-lobed grab bucket, the minimum pixel distance between the grab bucket and the hatch can be obtained by calculating the minimum distance between the two polygons; when the grab bucket is a six-lobed grab bucket, the minimum pixel distance between the grab bucket and the hatch can be obtained by calculating the minimum distance between the circle and the polygon. Finally, based on the pixel equivalent corresponding to the hatch height, the relative physical distance between the grab bucket and the hatch can be obtained.

[0042] Step S4: Obtain the real-time motion state parameters and external working condition parameters of the gantry crane lifting mechanism, luffing mechanism, and slewing mechanism to obtain the real-time stopping distance of the three mechanisms under the current working condition. Then, obtain the comprehensive stopping distance through the three-dimensional spatial synthesis model. Finally, combine the safety factor and the working condition correction factor to obtain the safety threshold. Specifically, to ensure the gantry crane grab can stop safely and controllably during operation, effectively avoiding safety risks such as snagging and crushing, the calculation of safety thresholds for snagging and crushing protection needs to comprehensively consider the motion parameters of the gantry crane's hoisting mechanism, luffing mechanism, and slewing mechanism, as well as external influencing factors under operating conditions. Specifically, the speed of the mechanism motor encoder can be directly obtained, deceleration can be calculated through feedback from brake current and torque sensors, material weight can be directly obtained through the tension sensor of the hoisting mechanism, wind speed is obtained from a three-dimensional airflow measured by an ultrasonic anemometer installed on the top of the gantry crane, and mechanism efficiency can be corrected online through brake wear detection and motor temperature data. The motion of the hoisting mechanism directly affects the vertical motion of the grab, the luffing mechanism determines the radial motion characteristics of the grab in the horizontal direction, and the slewing mechanism controls the tangential motion trajectory of the grab in the horizontal direction. Logically, the real-time stopping distances of the three mechanisms under the current operating conditions must first be obtained separately, then a comprehensive stopping distance is obtained through a three-dimensional spatial synthesis model, and finally, the final safety threshold is determined by combining the safety factor and the operating condition correction factor.

[0043] The calculation of the safety threshold includes: calculating the stopping distance in the lifting direction, the stopping distance in the luffing direction, and the stopping distance in the rotation direction respectively, and using a three-dimensional spatial synthesis model to calculate the comprehensive stopping distance.

[0044] Stopping distance in the lifting direction:

[0045]

[0046]

[0047] ( (The area facing the wind in the direction of ascent) Stopping distance in the direction of amplitude change:

[0048]

[0049]

[0050] Distance to stop in the direction of rotation:

[0051]

[0052]

[0053]

[0054] Total moment of inertia of the gantry crane's rotating mechanism (including the grab bucket and material). The rotating mechanism itself has a moment of inertia (excluding the grab bucket and the material). 3D spatial stopping distance synthesis model:

[0055] , indicating the intensity of the kinematic coupling between mechanisms; Safety threshold setting:

[0056]

[0057] In the formula: , , Real-time motion speeds of hoisting, luffing, and rotation (m / s, m / s, rad / s). , , Maximum deceleration during hoisting, luffing, and rotation ( ); r: Grab bucket rotation radius (m); m: Total mass of the grab bucket and the material; g: Acceleration due to gravity; The maximum output braking force of the brakes on the hoisting, luffing, and slewing mechanisms; Mechanical transmission efficiency of the hoisting / luffing / slewing mechanism; The coefficient of friction of the hoisting / luffing / spinning mechanism; The drag coefficient needs to be adjusted according to the shape of the grab bucket, for example, a two-lobed grab bucket. The value ranges from 0.8 to 1.2; it is a six-lobed circular grab. The value ranges from 0.5 to 0.8; A: Projected area of ​​the grab bucket; Real-time wind speed; Air density, taken as standard value; Safety factor, in this invention, The value range is 1.3 to 1.6; : Wind condition correction factor (the higher the wind speed, the larger the value), for example, for wind speeds < 5 m / s, 1.0, wind speed 5~10 m / s, 1.1 ~ 1.3, wind speed 10 ~ 15 m / s, 1.3 ~ 1.6; Material weight correction factor: Material weight affects inertial force and braking distance; braking distance is shorter under light load and longer under heavy load, and longer under no-load conditions. =1.0, at full load =1.2; : Mechanism wear correction factor, take 1.1 ~ 1.2 for severe brake wear.

[0058] Based on deep learning-based target detection and image segmentation, combined with pinhole projection transformation, the physical distance between the grab and the hatch can be calculated in real time and accurately, unaffected by incomplete point clouds in the hatch. Dynamic safety thresholds comprehensively consider the motion states of the three mechanisms, loads, wind speed, wear, and other actual operating conditions, avoiding false alarms or missed alarms caused by fixed thresholds.

[0059] The braking control incorporates a swing angle safety constraint, including setting a maximum permissible swing angle and calculating the maximum permissible horizontal deceleration based on a simple pendulum dynamics model, to prevent the grab bucket from swaying dangerously relative to the hoist due to excessive braking as it passes through the steel cable. When the grab bucket is stationary or moving at a constant speed, the steel cable points vertically downwards, and the swing angle θ = 0°.

[0060] When the gantry crane brakes suddenly in the horizontal direction (luffing or rotation), the grab bucket continues to move forward due to inertia, and the steel cable tilts backward. At this time, the swing angle θ is the angle at which the steel cable deviates from the vertical direction.

[0061] To prevent the grab bucket from dangerously swaying relative to the hoist via the steel cable due to excessive braking, a maximum permissible swing angle is set. (Typically taken as 10°~15°), according to the simple pendulum dynamics model, the maximum permissible horizontal deceleration is:

[0062] If the gate brake can provide the maximum deceleration, then the actual braking deceleration is limited, and the safety threshold under the swing angle constraint is recalculated:

[0063] The final safety threshold is the maximum value of the original threshold and the swing angle constraint threshold:

[0064] Tiered braking strategy: Warning phase: When the distance is greater than the safety threshold but less than... At that time, with the first deceleration Deceleration; Emergency braking phase: when the distance is less than At the maximum permissible deceleration Decelerate to a stop; The aforementioned automated gantry crane grab bucket hanger and hanger crush protection methods also include vibration suppression for braking in the lifting direction: the maximum permissible lifting deceleration is calculated based on the elastic modulus, cross-sectional area and suspension length of the steel cable.

[0065] For the lifting direction, the maximum permissible lifting deceleration is calculated based on the elastic modulus E of the steel cable, the cross-sectional area A, and the suspension length L:

[0066] Where SF is the safety factor (e.g., 0.5). The breaking force of the steel cable shall not exceed the actual hoisting braking deceleration. .

[0067] By introducing swing angle safety constraints and a graded braking model, the grab bucket swing caused by emergency stop is effectively suppressed, preventing risks such as secondary collisions and cable derailment, and improving braking safety.

[0068] Step S5: Compare the physical distance with the safety threshold. When the physical distance between the grab bucket and the hatch is less than the safety threshold, execute the hatch attachment or crash protection alarm and trigger the door mechanism braking control.

[0069] Specifically, when the distance between the grab bucket and the hatch opening is less than a safety threshold, a hatch protection detection alarm will be triggered. During hatch impact detection, when the distance between the grab bucket and the hatch opening is less than a safety threshold, and the height difference between the grab bucket and the hatch opening is less than a safety threshold, a hatch impact protection detection alarm will be triggered.

[0070] Furthermore, with increasing demands for port operational efficiency, simultaneous and shared operations of two gantry cranes in the same hold have become a routine and highly efficient practice. However, single-gantry crane protection solutions have the following drawbacks: the risk of spatial interference between the two cranes (double grabs are prone to collision in narrow hatches), target detection confusion (misalignment in double grab scenarios with a single hatch), and the lack of a coordinated control mechanism. Additionally, during emergency braking, the grab is suspended below the hoisting mechanism by flexible steel cables. If braking is too abrupt, the grab will sway significantly relative to the hoist due to inertia (pendulum effect), potentially leading to secondary collisions, cable fatigue, or even derailment, among other new safety issues.

[0071] A pre-trained deep learning multi-ID object detection and instance segmentation model is used to process images captured by the global camera in real time, and output detection results with unique ID identifiers, including: master grab M1, slave grab M2, globally unique hatch outline and four corner points, and height information of the material surface inside the hold; through the ID tracking and binding mechanism, it is ensured that there will be no target confusion and ID switching problems during the movement of the two grabs, thus solving the defect of target detection confusion in the two machines.

[0072] During the operation, the pixel coordinates collected by the local cameras of the two gantry cranes are uniformly mapped to the global coordinate system through perspective transformation, eliminating the coordinate deviation caused by the different viewpoints of the two machines and ensuring that the distance calculation of the two machines is based on the same coordinate reference.

[0073] In the global coordinate system, the system calculates the minimum physical distance D1 between the main grab M1 and the hatch; the minimum physical distance D2 between the slave grab M2 and the hatch; and the spatial interference distance D12 between the main grab M1 and the slave grab M2. When the grab bucket is in the cabin lifting and exiting phase, the following protection logic is executed in the shared cabin mounting protection mode: Dual-machine independent pod detection: Execute the original single-machine pod detection logic for each of the two gantry cranes. When D1 < the single-machine pod detection threshold between the main grab bucket M1 and the hatch... 1, or D2 < the single-bay threshold of the slave grab M2 and the hatch. At time 2, the risk of a single aircraft attaching a bay was determined to be triggered.

[0074] Co-fighting interference detection: A new dual-machine interference risk detection method has been added. The spatial interference distance D12 between the two grabs is calculated. When D12 < D_safe, a dual-machine interference risk is determined to exist, where D_safe is the safe distance for co-fighting interference, calculated using the following formula:

[0075] In the formula, , These are the three-dimensional composite stopping distances of the two gantry cranes. An additional safety margin is provided for shared cabin operations, with a value ranging from 0.1 to 0.3 m, which can be adaptively adjusted according to the operating conditions.

[0076] For dual-gantry crane operations in shared compartments, a global multi-ID detection, unified coordinate mapping, interference detection, and collaborative control mechanism is proposed. This solves industry challenges such as target confusion, spatial interference, and lack of collaborative control. Furthermore, the local pixel coordinates of the two cranes are unified to the global coordinate system through perspective transformation, eliminating coordinate deviations caused by different viewpoints and providing a unified benchmark for dual-crane interference calculations. Spatial interference distance and shared compartment safety distance are defined, enabling real-time calculation and comparison of collision risks between the two cranes. This gives the system protective capabilities for shared compartment operations, meeting the port's efficiency improvement needs.

[0077] Alarm and protective actions: When any risk condition is met, a graded alarm is triggered: For the gantry crane with a risk, it will be stopped immediately to prevent the grab bucket from getting closer to the hatch; the other gantry crane will automatically enter the avoidance control mode and be prohibited from moving into the overlapping work area to avoid escalating the risk of collision. The overlapping work area of ​​the hatches is locked globally until the risk is completely eliminated, then the lock is released and the dual-aircraft shared cabin operation is resumed.

[0078] When the grab bucket is in the external descent and entry phase, the following protection logic is executed in the shared compartment collision protection mode: Three new types of shared cabin-specific constraints have been added to resolve conflicts during simultaneous descent of two aircraft: 1. Mutual exclusion of overlapping areas: Only one grab bucket is allowed to enter the vertical projection overlapping area of ​​the hatch at the same time, and it is prohibited for two grabs to work in the overlapping area at the same time. 2. Height Interlock: Within the same working area, two grab buckets are not allowed to be lower than the preset safe height at the same time to prevent collisions between the two machines at low altitudes; 3. Descent timing control: When two gantry cranes apply to enter the overlapping area for operation at the same time, the principle of "first come, first served" shall be adopted. The gantry crane that applies later shall enter the waiting queue until the first gantry crane completes its operation and leaves the overlapping area before it is allowed to enter. Alarm and protective actions: When any risk condition is met, immediately stop the descent of the grab bucket and simultaneously lock the movement of both gantry cranes toward the hatch; after the overlapping area is cleared, resume dual-machine operation according to the requested sequence.

[0079] The dynamic safety threshold for shared cabin operations incorporates a shared cabin correction coefficient to achieve dynamically adaptive calculation of the shared cabin safety threshold. The specific formula is as follows:

[0080] This is the overlap area coefficient, adjusted based on the overlap area of ​​the two-machine operating areas. The larger the overlap area, the larger the value. Specifically, when the overlap area of ​​the two machines is 0... The value can be 1, when the overlapping area reaches the total area of ​​the hatch and the two aircraft cannot be staggered. The possible value is 1.5; The interference risk coefficient is adjusted based on the relative direction and speed of the two machines. The coefficient increases when they move towards each other and decreases when they move in the same direction. When the two machines move away from each other in the same direction and at the same speed, the actual collision risk is lower than that of single-machine operation, and the safety threshold can be appropriately reduced, but it cannot be reduced indefinitely. A value of 0.8 can be used when the two machines approach each other at high speed. It can take the value 1.8; This is the synchronization coefficient between the two machines, adjusted according to their operational synchronization degree. The higher the synchronization degree, the smaller the coefficient. The risk is lowest when the two machines are completely synchronized and their operation cycles are consistent. A value of 0.7 is acceptable. When the two machines are operating completely out of sync, i.e., randomly and chaotically, the risk is higher than in normal operating conditions. It can take the value 1.2.

[0081] Ultimate safety threshold for shared cabins:

[0082] This threshold can be updated in real time based on parameters such as the relative distance between the two machines, the overlapping area, wind speed, load, and the motion status of the two machines. In other words, it takes into account the situation that the grab bucket will swing significantly relative to the hoist due to inertia during the braking process, adapting to different working conditions and balancing safety and work efficiency.

[0083] The dynamic safety threshold for shared compartments can be adaptively adjusted based on the overlapping area, relative movement direction, and synchronization, thereby improving the efficiency of shared compartment operations while ensuring safety.

[0084] On the other hand, the present invention also provides an automated gantry crane grab bucket hull-mounting and hull-crushing protection system, which applies the aforementioned automated gantry crane grab bucket hull-mounting and hull-crushing protection method, including: Self-stabilizing camera, mounted on the gantry crane's trunk platform; The image processing module is used to perform deep learning object detection and image segmentation; The distance calculation module is used to perform pixel coordinate transformation, projection transformation, and physical distance calculation. The dynamic safety threshold calculation module is used to calculate the final safety threshold based on the mechanism's motion state, operating parameters, and swing angle constraints. The alarm and braking control module is used to trigger graded alarms and execute graded braking with swing angle limits. This system can be superimposed on the existing gantry crane PLC control system as a standalone safety system, or it can be integrated into an automated dispatching platform to adapt to different port renovation needs.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for protecting the grab bucket of an automated gantry crane from being attached to or crushed by the hull, characterized in that, Includes the following steps: The video streams of the grab bucket and the hatch are obtained by the camera, and the pixel coordinates of the grab bucket and the hatch in the image are identified and obtained in real time. The pixel coordinates of the grab are converted into normalized planar coordinates, and the position of the grab is projected onto the height plane of the hatch to obtain normalized pixel coordinates. Calculate the minimum pixel distance between the grab and the hatch in the image, and convert the minimum pixel distance into a physical distance based on pixel equivalents; The real-time motion state parameters and external working condition parameters of the gantry crane hoisting mechanism, luffing mechanism and slewing mechanism are obtained to obtain the real-time stopping distance of the three mechanisms under the current working condition. The comprehensive stopping distance is then obtained through a three-dimensional spatial synthesis model. Finally, the safety threshold is obtained by combining the safety factor and the working condition correction factor. The physical distance is compared with the safety threshold. When the physical distance between the grab bucket and the hatch is less than the safety threshold, a hatch attachment or crash protection alarm is triggered, and the door mechanism braking control is activated.

2. The automated gantry crane grab bucket anti-cab and anti-cab protection method as described in claim 1, characterized in that, The calculation of the safety threshold includes: calculating the stopping distance in the lifting direction, the stopping distance in the luffing direction, and the stopping distance in the rotation direction respectively, and using a three-dimensional spatial synthesis model to calculate the comprehensive stopping distance.

3. The method for protecting the automated gantry crane grab bucket from being attached to or crushed by the hull, as described in claim 2, is characterized in that... The braking control incorporates a swing angle safety constraint, including setting a maximum permissible swing angle and calculating the maximum permissible horizontal deceleration based on a simple pendulum dynamics model, to prevent the grab bucket from swinging dangerously relative to the hoist via the steel cable due to excessive braking.

4. The method for protecting the automated gantry crane grab bucket from being attached to or crushed by the hull, as described in claim 3, is characterized in that... It also includes sway suppression for braking in the lifting direction: the maximum permissible lifting deceleration is calculated based on the elastic modulus, cross-sectional area, and suspension length of the steel cable.

5. The method for protecting the automated gantry crane grab bucket from being attached to or crushed by the hull as described in claim 1, characterized in that, It also includes shared-cabin operation modes, including: The pixel coordinates acquired by the two gantry cameras are uniformly mapped to the global coordinate system through perspective transformation; Calculate and compare the spatial interference distance D12 between the main grab M1 and the slave grab M2 and the co-cabin interference safety distance D_safe in the global coordinate system to determine whether there is a risk of dual-machine interference.

6. The method for protecting the automated gantry crane grab bucket from being attached to or crushed by the hull, as described in claim 5, is characterized in that... The shared cabin operation mode adds shared cabin-specific constraints: overlapping area mutual exclusion constraint: only one grab bucket is allowed to enter the vertical projection overlap area of ​​the hatch at the same time; height interlock constraint: two grab buckets are not allowed to be lower than the preset safe height at the same time; descent sequence control constraint: the principle of first-come, first-served is adopted, and the gantry crane that applies later enters the waiting queue; when any constraint is violated, the grab bucket descent action is immediately stopped, the movement of the two gantry cranes toward the hatch is locked, and the operation is resumed according to the application sequence after the overlapping area is cleared.

7. The method for protecting the automated gantry crane grab bucket from being attached to or crushed by the hull as described in claim 6, characterized in that, The dynamic safety threshold for shared cabin operations incorporates overlapping area coefficients, interference risk coefficients, and dual-machine synchronization coefficients to achieve dynamically adaptive calculation of the shared cabin safety threshold.

8. The method for protecting the automated gantry crane grab bucket from being attached to or crushed by the hull as described in claim 1, characterized in that, The minimum pixel distance is calculated as follows: when the grab is a two-lobed grab, the minimum pixel distance between the grab and the hatch is obtained by calculating the minimum distance between the two polygons; when the grab is a six-lobed grab, the minimum pixel distance between the grab and the hatch is obtained by calculating the minimum distance between the circle and the polygon.

9. The method for protecting the automated gantry crane grab bucket from being snagged or crushed as described in claim 1, characterized in that, The operating condition correction factors include wind condition correction factor, material weight correction factor, and mechanism wear correction factor.

10. An automated gantry crane grab bucket hangar and hangar crush protection system, characterized in that, The method described in any one of claims 1 to 9 includes: Self-stabilizing camera, mounted on the gantry crane's trunk platform; The image processing module is used to perform deep learning object detection and image segmentation; The distance calculation module is used to perform pixel coordinate transformation, projection transformation, and physical distance calculation. The dynamic safety threshold calculation module is used to calculate the final safety threshold based on the mechanism's motion state, operating parameters, and swing angle constraints. The alarm and braking control module is used to trigger graded alarms and perform graded braking with swing angle limits.

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