A method for controlling the precision of the lifting posture of a prefabricated steel box girder at sea

Abstract

This invention relates to the field of construction technology, and in particular to a method for controlling the posture accuracy of precast steel box girders being hoisted at sea. The method includes: preparing the precast steel box girder to be hoisted; simultaneously controlling the main and auxiliary cranes to lift and transport the precast steel box girder from an initial position to a first preset position; detecting the stress on each sling and the inclination degree of the precast steel box girder when it is at the first preset position to redetermine the working mode of the main and auxiliary cranes, or to determine the working state of each sling; controlling the main and auxiliary cranes to move the precast steel box girder to a second preset position based on the determined translational displacement speed; periodically detecting the posture and position of the precast steel box girder during the movement to determine the working mode of the main and auxiliary cranes, or to determine the working state of each sling; enabling highly efficient and precise hoisting of precast steel box girders at sea.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a method for controlling the posture accuracy of precast steel box girders being hoisted at sea. Background Technology

[0002] The dual-crane hoisting method for steel box girders involves using a main crane and an auxiliary crane to lift the precast steel box girder from its initial location to the target position through multiple lifting points, achieving a stable and precise hoisting operation. However, during the hoisting of precast steel box girders at sea, environmental factors such as sea breezes and tides can cause the precast steel box girder to sway and shift during the hoisting process, leading to changes in the hoisting posture and errors in the hoisting point positioning.

[0003] Chinese Patent Publication No. CN120553554A discloses a steel box girder hoisting device for building construction, relating to the field of building construction technology. The device places the lifting tool at the tail of the main hook and the auxiliary hook. During hoisting, under the action of the weight of the steel box girder being hoisted, the lifting tool moves from the tail of the main hook and the auxiliary hook towards the middle, causing the auxiliary hook to rotate relative to the main hook, so that the middle of the auxiliary hook gradually approaches the middle of the main hook, that is, the auxiliary hook gradually changes from a state of separation from the main hook to a state of merging with the main hook. During rotation, the auxiliary hook is restricted by the damping mechanism, which slows down the speed at which the lifting device moves from the tail of the main hook and auxiliary hook towards the center, thus playing a shock absorption role. That is, at the moment of lifting and loading, when the lifting device is subjected to instantaneous impact force, the damping mechanism absorbs the impact stress generated between the auxiliary hook and the lifting device. When the lifting device moves from the tail of the main hook and auxiliary hook towards the center, the auxiliary hook provides lateral support and limit for the lifting device, reducing the unstable swaying of the lifting device and reducing the impact on the stability and construction safety of the steel box girder lifting. However, this patent has the problem that it cannot overcome the problem of environmental factors affecting the accuracy of lifting precast steel box girders at sea. Summary of the Invention

[0004] To address this issue, the present invention provides a method for controlling the posture accuracy of precast steel box girders during offshore hoisting, thereby overcoming the problem in the prior art where the hoisting landing point cannot be accurately controlled due to interference from sea winds and tides during the transportation of precast steel box girders at sea.

[0005] To achieve the above objectives, the present invention provides a method for controlling the posture accuracy of precast steel box girders being hoisted at sea, comprising, Prepare for the hoisting of precast steel box girders; The main and auxiliary cranes are synchronously controlled to lift and transport the precast steel box girder from the initial position to the first preset position. The stress of each sling and the degree of inclination of the precast steel box girder when it is in the first preset position are detected to redetermine the working mode of the main and auxiliary cranes, or to determine the working status of each sling. Determining the working modes of the main and auxiliary cranes includes determining the translational displacement speed for transporting the precast steel box girder from the first preset position to the second preset position; Based on the determined translational displacement speed, the main and auxiliary cranes are controlled to move the precast steel box girder to the second preset position. The attitude and position of the precast steel box girder during the movement are periodically detected, and the working mode of the main and auxiliary cranes, or the working status of each sling is determined. The periodic inspection intervals vary depending on the position of the precast steel box girder during its movement.

[0006] Furthermore, the attitude of the precast steel box girder is determined based on the stress conditions of each suspender cable, including: The control unit acquires data from each tension sensor used to detect the tension between the slings connected to the main crane and the auxiliary crane and the lugs of the precast steel box girder, and determines the dynamic load distribution error at the corresponding points of each tension sensor; The errors in the distribution of each dynamic load are assessed to determine their compliance. The working status of each sling is determined based on the number and location of non-compliant dynamic load distribution errors.

[0007] Furthermore, based on the inclination angle of the precast steel box girder, the attitude of the precast steel box girder is determined, including: The control unit acquires the values ​​of the tilt sensors installed at the four corners of the top plate of the precast steel box girder and determines the angular offset of the tilt sensors. The angular offset of each tilt sensor is determined to confirm its qualification. The working status of each sling is determined based on the number and location of the non-compliant angular offsets.

[0008] Furthermore, based on the fact that the precast steel box girder has reached the first preset position, the actual position of the precast steel box girder is determined, including: The control unit acquires the actual coordinate data of several measurement points located at the midpoint of each edge of the rectangular top plate of the precast steel box girder, and determines the difference between the actual coordinate data of each measurement point and the three-dimensional coordinate data of the preset coordinate data. The differences in the three-dimensional coordinate data of each measurement point are judged to determine its compliance. Based on the number and location of the discrepancies in the non-compliant three-dimensional coordinate data, determine the working mode of the main and auxiliary cranes, or determine the working status of each sling.

[0009] Furthermore, based on the dynamic load distribution error and angular offset after the precast steel box girder is initially lifted and transported from its initial position to the first preset position, the lifting speed of the precast steel box girder for the next lifting and transport is re-determined.

[0010] Furthermore, the initial interval for periodic detection is determined based on the posture and displacement velocity of the precast steel box girder after being repositioned at the first preset position, and the variable interval for the second translation stage is determined after the first translation stage is completed. The first translation stage ends at the position after half of the translation stage from the first preset position to the second preset position, at the position where the initial detection interval is determined.

[0011] Furthermore, the interval duration of the variable interval is related to the remaining distance; the shorter the remaining distance during the second translation phase, the shorter the detection interval.

[0012] Furthermore, based on the determination of the actual position of the precast steel box girder after the first translation stage, the displacement velocity of the precast steel box girder in the second translation stage is determined.

[0013] Furthermore, the displacement velocity is determined based on the posture of the precast steel box girder after being redefined at the second preset position. The precast steel box girder is then lowered from the second preset position and transported to the target position. Periodic inspections are conducted during the movement, and the displacement velocity of the precast steel box girder before the next inspection is determined based on the determination of the posture and position of the precast steel box girder after each inspection.

[0014] Furthermore, the working state of each sling includes the lowering length of each sling.

[0015] Compared with the prior art, the beneficial effect of the present invention is that the process of hoisting precast steel box girders at sea is divided into three stages. After the preparation stage for hoisting the steel box girder is completed, the precast steel box girder is first vertically lifted from the initial position for a lifting and transportation process. The precast steel box girder is lifted and transported to the first preset position. During the hoisting process of the first stage, the attitude of the precast steel box girder during the lifting and transportation process is monitored in real time and the attitude is corrected in a timely manner to ensure that the precast steel box girder is hoisted smoothly and at a uniform speed. After reaching the first preset position and completing the first stage of hoisting, the attitude and position of the hoisted precast steel box girder are detected and judged. After the judgment, the attitude and position of the precast steel box girder are adjusted to ensure the accuracy of the attitude and position of the precast steel box girder after reaching the first preset position, and to ensure the accuracy of subsequent hoisting of the precast steel box girder, thus completing the first stage of hoisting.Then, the second stage of precast steel box girder translation and transportation is carried out. Based on the posture of the precast steel box girder after the first stage of hoisting, the translation and transportation speed of the precast steel box girder is determined, and the precast steel box girder is translated and transported from the first preset position to the second preset position. During the translation and transportation process, the movement posture of the transported precast steel box girder is monitored in real time, and the movement position of the precast steel box girder is periodically detected. Adjustments are made to the periodic detection during the second stage of precast steel box girder translation and transportation based on the posture of the precast steel box girder after the first stage of hoisting, so that the periodic adjustment can overcome the first stage The positional deviation caused by hoisting is addressed by adjusting the displacement speed based on the movement posture of the precast steel box girder during periodic testing. This ensures the precast steel box girder can be hoisted smoothly and accurately to the second preset position. At this second preset position, the posture and position of the hoisted precast steel box girder are again detected and judged, and then corrected to ensure accuracy in subsequent hoisting. Furthermore, the second preset position is numerically above the target hoisting position. Therefore, after the second stage of precast steel box girder hoisting is completed, the first stage's deviation can be overcome again. The error after hoisting the precast steel box girder is considered. After completing the second stage of precast steel box girder hoisting, the third stage is performed. Once the precast steel box girder reaches the second preset position and its attitude and position are determined and adjusted, the difficulty of hoisting the precast steel box girder is significantly reduced, and the accuracy of the hoisting is greatly improved. Finally, the third stage of precast steel box girder hoisting is carried out. Based on the attitude and position adjusted after the second stage of hoisting, the speed of lowering and transporting the precast steel box girder in the third stage is determined, as is the cycle time during the third stage of lowering and transporting the precast steel box girder. The process involves inspecting the posture and position of the precast steel box girders, and periodically adjusting the displacement speed of the lowering and transporting girders based on their posture. This ensures accurate posture and precise positioning during hoisting. After the precast steel box girders are lowered and transported, another inspection and assessment is conducted, and the posture and position of the girders are corrected to ensure accuracy in both position and posture. This ensures the accuracy of offshore steel box girder hoisting and construction, and allows for experience summarization and data analysis to improve the accuracy and speed of subsequent precast steel box girder hoisting. Furthermore, using this hoisting experience as a reference, the speed during the first stage of lifting and transporting the precast steel box girders can be adjusted to improve the accuracy and speed of repeated hoisting operations.

[0016] Furthermore, during the process of slowly and uniformly lifting and transporting the precast steel box girder from its initial position to the first preset position, the tension distribution and angular deviation of the precast steel box girder are continuously monitored, and its posture is adjusted in a timely manner to ensure that the precast steel box girder is transported smoothly and accurately to the first preset position. After transportation to the first preset position, the tension distribution, angular deviation, and position of the precast steel box girder are detected and adjusted accordingly to ensure the subsequent hoisting construction of the precast steel box girder. This reduces the errors generated during the lifting and transportation of the precast steel box girder from its initial position to the first preset position, ensuring that the hoisted precast steel box girder is installed with precise posture and position during construction. Moreover, when hoisting the precast steel box girder again in a subsequent manner, the initial speed can be set based on the previously completed precast steel box girder construction, which increases the convenience of multiple hoisting operations, speeds up the hoisting process, reduces hoisting errors, and completes the construction more quickly, safely, and accurately.

[0017] Furthermore, after the precast steel box girder is hoisted to the first preset position, its attitude and position are adjusted. Based on the deviation between the attitude and position of the precast steel box girder after adjustment and the attitude under ideal conditions, the initial preset periodic detection interval and initial displacement speed during the translation and transportation process are adjusted to overcome the deviation generated during the transportation of the precast steel box girder from the initial position to the first preset position. By monitoring the angular offset and tension distribution of the precast steel box girder in real time during the translation and transportation of the precast steel box girder from the first preset position to the second preset position, the attitude is adjusted in real time. Combined with periodic detection of the position deviation of the precast steel box girder and adjustment of the displacement speed, the interference of external forces on the precast steel box girder during the translation and transportation process is overcome, ensuring that the precast steel box girder can be hoisted to the designated position smoothly and accurately within the allowable error range according to the simulated path, and thus carry out smooth and accurate hoisting construction.

[0018] Furthermore, after the precast steel box girder is hoisted to the second preset position, its attitude and position are adjusted. Based on the deviation between the adjusted attitude and position of the precast steel box girder and its ideal state, the initial preset periodic detection interval and initial displacement speed during the lowering and transportation process are adjusted to overcome the deviation generated during the transportation of the precast steel box girder from the first preset position to the second preset position. By monitoring the angular offset and tension distribution of the precast steel box girder in real time during the lowering and transportation process from the second preset position to the target position, the attitude is adjusted in real time. Combined with periodic detection of the position deviation of the precast steel box girder and adjustment of the displacement speed, the interference of external forces on the precast steel box girder during the lowering and transportation process is overcome, ensuring that the precast steel box girder can be hoisted to the designated position smoothly and accurately within the allowable error range according to the simulated path, and the hoisting construction is carried out smoothly and accurately. After the hoisting is completed, the position and attitude of the hoisted precast steel box girder are finely adjusted according to the actual construction requirements to complete the high-precision installation of the precast steel box girder.

[0019] Furthermore, by overcoming the external forces exerted on the ship's hull by the external environment, the ship's hull is ensured to remain in an ideal position within the allowable error range. This ensures the precise positioning of the crane used for lifting precast steel box girders at sea, and further ensures that, with the ship's hull in a precise position, multiple precast steel box girders can be lifted with precise attitude control and accurate position and height. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the process of hoisting a precast steel box girder at sea, as described in this invention. Figure 2 This is a flowchart illustrating the determination of the steel box girder's attitude based on the stress conditions of each suspender cable, as per the present invention. Figure 3 This is a flowchart illustrating the process of determining the attitude of a steel box girder based on its tilt angle, as described in this invention. Figure 4 This is a schematic diagram showing the positions of various sensors during the hoisting of precast steel box girders at sea, as per the present invention.

[0021] In the diagram: 1. Precast steel box girder; 2. Lifting lug; 3. Tension sensor; 4. Displacement sensor; 5. Measuring point. Detailed Implementation

[0022] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0023] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0024] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0025] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] Please see Figure 1 The diagram shows a flowchart for the hoisting of precast steel box girders at sea, designed to control the attitude accuracy of the girders. This invention provides a method for controlling the posture accuracy of precast steel box girders being hoisted at sea, comprising, Preparations are made for the hoisting of the precast steel box girder, including the main and auxiliary cranes arriving at the lifting position, checking the installation of the lifting equipment and the center of gravity, and then connecting the main and auxiliary cranes to the precast steel box girder. The main crane and the auxiliary crane are controlled to simultaneously lift and transport the precast steel box girder from the initial position to the first preset position. At the same time, the attitude of the precast steel box girder is determined and adjusted. After the precast steel box girder reaches the first preset position, its position is determined and adjusted. The main crane and the auxiliary crane determine the displacement speed of the precast steel box girder based on its posture when it is lifted and transported from the initial position to the first preset position. They then translate the precast steel box girder from the first preset position to the second preset position, while simultaneously determining and adjusting the posture of the precast steel box girder. The position of the precast steel box girder is periodically detected and the translation speed is adjusted accordingly. After the precast steel box girder reaches the second preset position, its position is determined and adjusted. The main crane and the auxiliary crane lower the precast steel box girder from the second preset position to the target position. At the same time, the attitude of the precast steel box girder is determined and adjusted, and the position of the precast steel box girder is periodically detected and the translation speed is adjusted. After the precast steel box girder reaches the target position, the position is determined and adjusted, and the connection between the main crane and the auxiliary crane and the precast steel box girder is disconnected to complete the hoisting construction of a single precast steel box girder. Repeat the above hoisting process to complete the hoisting of multiple precast steel box girders.

[0027] The process of hoisting precast steel box girders at sea is divided into three stages. After the preparatory stage for hoisting the steel box girders is completed, the precast steel box girders are first vertically lifted from their initial positions and transported to the first preset position. During the first stage of hoisting, the attitude of the precast steel box girders is monitored in real time and the attitude is corrected in a timely manner to ensure that the precast steel box girders are hoisted smoothly and at a uniform speed. After reaching the first preset position and completing the first stage of hoisting, the attitude and position of the hoisted precast steel box girders are detected and judged. After the judgment, the attitude and position of the precast steel box girders are adjusted to ensure the accuracy of the attitude and position of the precast steel box girders after reaching the first preset position, so as to ensure the accuracy of subsequent hoisting of the precast steel box girders, thus completing the first stage of hoisting. Then, the second stage of precast steel box girder translation and transportation is carried out. Based on the posture of the precast steel box girder after the first stage of hoisting, the translation and transportation speed of the precast steel box girder is determined, and the precast steel box girder is translated and transported from the first preset position to the second preset position. During the translation and transportation process, the movement posture of the transported precast steel box girder is monitored in real time, and the movement position of the precast steel box girder is periodically detected. Adjustments are made to the periodic detection of the precast steel box girder during the second stage of translation and transportation based on the posture of the precast steel box girder after the first stage of hoisting. This periodic adjustment can overcome the positional deviation caused by the first stage of hoisting, and the displacement speed is adjusted according to the movement posture of the precast steel box girder during the periodic detection to ensure that the precast steel box girder can be transported smoothly and accurately. The precast steel box girder is hoisted to the second preset position, where its posture and position are again checked and determined. After determination, the posture and position of the precast steel box girder are corrected to ensure accuracy in subsequent hoisting. Since the second preset position is numerically above the target hoisting position, the second stage of precast steel box girder hoisting overcomes the errors from the first stage. After the second stage, the third stage of precast steel box girder hoisting is carried out. By reaching the second preset position and completing the posture and position determination and adjustment, the difficulty of hoisting the precast steel box girder is significantly reduced, and the accuracy of the hoisting is greatly improved. Finally, the third stage involves the hoisting of the precast steel box girders. Based on the posture and position adjustments made after the second stage of hoisting, the speed for lowering and transporting the precast steel box girders in the third stage is determined. During this process, the posture and position of the precast steel box girders are periodically checked, and the displacement speed is adjusted accordingly to ensure accurate posture and precise position. After the hoisting is completed, the precast steel box girders are again inspected and assessed, and their posture and position are corrected to ensure accuracy. This ensures the accuracy of the position and posture of the hoisted precast steel box girders, guaranteeing the accuracy of offshore steel box girder hoisting and construction. This experience can be used to summarize lessons learned and compile data to improve the accuracy and speed of future precast steel box girder hoisting operations. Using this lifting of precast steel box girders as a reference, the speed during the first stage of lifting and transporting precast steel box girders will be adjusted to increase the accuracy and speed of repeated lifting of precast steel box girders.

[0028] Specifically, an embodiment for determining whether the attitude and position of the precast steel box girder are stable during the hoisting process from the initial position to the first preset position and after reaching the first preset position, and for correcting errors: The first stage of the hoisting and transportation process includes, During the process of the main crane and the auxiliary crane lifting the precast steel box girder to the first preset position, The control unit acquires data from each tension sensor used to detect the tension between the slings connected to the main crane and the auxiliary crane and the lugs of the precast steel box girder, and determines the dynamic load distribution error at the corresponding point of each tension sensor. The calculation process for the dynamic load distribution error includes: The absolute value of the difference between the actual value and the predetermined value of each tension sensor; The dynamic load distribution error is determined by dividing the absolute value of the difference by a predetermined value.

[0029] For any dynamic load distribution error, compare it with the predetermined distribution error value. If the value of the dynamic load distribution error is less than or equal to the predetermined distribution error value, the dynamic load distribution error of the corresponding point is deemed to be qualified. If the value of the dynamic load distribution error is greater than the predetermined distribution error value, the dynamic load distribution error of the corresponding point is deemed unqualified. If there is one and only one unqualified value of dynamic load distribution error, the control unit controls the crane of the sling corresponding to the tension sensor whose dynamic load distribution error value is unqualified to pull the corresponding sling to the value of dynamic load distribution error to the qualified state. If there are only two unqualified values ​​of dynamic load distribution error, the control unit compares the values ​​of the two dynamic load distribution errors. The control unit controls the crane of the sling corresponding to the tension sensor of the dynamic load distribution error with the larger error to pull the corresponding sling until the values ​​of the two dynamic load distribution errors are close. Then the control unit controls the crane of the sling corresponding to the tension sensor with the unqualified value of the two dynamic load distribution errors to pull the corresponding sling until the value of the dynamic load distribution error is qualified. If there are only three non-compliant dynamic load distribution errors, the control unit compares the values ​​of the three dynamic load distribution errors. The control unit controls the crane corresponding to the sling of the tension sensor corresponding to the dynamic load distribution error with the largest error to pull the corresponding sling until the dynamic load distribution error is close to the middle dynamic load distribution error. Then, the control unit controls the crane corresponding to the sling of the tension sensor corresponding to the middle dynamic load distribution error to pull the corresponding sling together with the first sling pulled, until the three dynamic load distribution errors are similar. Then, the control unit controls the crane corresponding to the sling of the tension sensor with the third non-compliant dynamic load distribution error to pull the corresponding sling, until the values ​​of the three dynamic load distribution errors are all compliant. The control unit acquires the values ​​of the tilt sensors installed at the four corners of the top plate of the precast steel box girder and determines the angular offset of the tilt sensors. The angular offset of any tilt sensor is compared with a predetermined angular offset. If the angle offset of the tilt sensor is less than or equal to the predetermined angle offset, the control unit determines that the angle offset of the tilt sensor at the corresponding point is qualified. If the angle offset of the tilt sensor is greater than or equal to the predetermined angle offset, the control unit determines that the angle offset of the tilt sensor at the corresponding point is unqualified. If the angle offset of one and only one tilt sensor is not up to standard, the control unit controls the sling corresponding to the nearest lifting point to that tilt sensor to adjust the length of the sling, so as to adjust the angle offset of the tilt sensor to be up to standard. If the angular offset of two tilt sensors is not up to standard, the control unit controls the two slings corresponding to the lifting points closest to the two tilt sensors to adjust their lengths, thereby adjusting the angular offset of the tilt sensors to the standard value. If there are only three tilt sensors whose angle offset is not up to standard, the control unit first controls the length of the sling corresponding to the tilt sensor whose angle offset is up to standard to adjust the angle offset of the tilt sensor to standard. Then, the control unit controls the length of the two slings corresponding to the remaining two tilt sensors whose angle offset is not up to standard until the angle offset of the two tilt sensors is up to standard. If the angular offset of the four tilt sensors is not up to standard, the control unit controls the stretching and position adjustment of the four slings until the angular offset of the two tilt sensors is up to standard.

[0030] The value of the dynamic load distribution error is determined based on the angle offset amount when the angle offset is within acceptable limits. Let the dynamic load distribution error be y, and the angular offset be x. The relationship between the dynamic load distribution error and the angular offset is as follows: y = 1.5 × x + 0.02; During the process of lifting and transporting the precast steel box girder from its initial position to the first preset position... Let the dynamic load distribution error be y1, and the angular offset be x1. y1 = 1.5 × x1 + 0.02; During the process of lifting and transporting the precast steel box girder from its initial position to the first preset position, after the main crane and the auxiliary crane lift the precast steel box girder to the first preset position, the control unit determines and adjusts the dynamic load distribution error of each tension sensor on the precast steel box girder; the control unit determines and adjusts the tilt angle of each tilt sensor on the precast steel box girder; and the control unit determines and adjusts the actual stopping position of the precast steel box girder relative to the preset first position. The control unit acquires the actual coordinate data of multiple measurement points located at the midpoint of each edge of the rectangular top plate of the precast steel box girder. The control unit compares the actual coordinate data of the multiple measurement points on the precast steel box girder with preset coordinate data, and compares the three-dimensional coordinate data differences between the actual coordinate data and the preset coordinate data of each measurement point. If the difference between the actual coordinate data of the measurement point and the three-dimensional coordinate data of the preset coordinate data is ≤2mm, the control unit determines that the precast steel box girder is accurately hoisted to the first preset position. If the difference between the actual coordinate data of the measurement point and the three-dimensional coordinate data of the preset coordinate data is greater than 2mm in longitude, greater than 2mm in latitude, or greater than 2mm in height, the control unit determines that the position of the precast steel box girder at the preset height is inaccurate. If there is only one measurement point whose position is inaccurate, the control unit controls the two slings closest to that measurement point to move synchronously until the position of the measurement point reaches a three-dimensional coordinate data difference of ≤2mm between the actual coordinate data and the preset coordinate data. If only two measuring points are inaccurate and are adjacent to each other, the control unit controls the length adjustment of the slings that are adjacent to the two measuring points until the two measuring points are inaccurate; if only two measuring points are inaccurate and correspond to each other, the control unit controls the four slings to move synchronously until all measuring points are inaccurate. If only three measuring points are inaccurate, the control unit controls the four slings distributed on both sides of the accurately positioned measuring points to rotate around the vertical line where the accurately positioned measuring points are located as the axis. Meanwhile, the other two slings adjust their lengths as they rotate around the vertical line where the accurately positioned measuring points are located as the axis, until the three measuring points are accurately positioned. If the positions of the four measuring points are inaccurate, the control unit controls the four slings to move synchronously to lift the precast steel box girder to the first preset position until the positions of the four measuring points are accurate.

[0031] During the process of lifting and transporting the precast steel box girder from its initial position to the first preset position, the speed at which the precast steel box girder is lifted from its initial position to the first preset position is set as v1, and the speed at which the precast steel box girder is lifted from its initial position to the first preset position in the next operation is set as v11. Let y1 be the dynamic load distribution error during the process of lifting and transporting the precast steel box girder from its initial position to the first preset position, and let x1 be the angular offset. y1 = 1.5 × x1 + 0.02; Based on the speed at which the precast steel box girder was lifted from its initial position to the first preset position and the dynamic load distribution error, the speed at which the precast steel box girder will be lifted from its initial position to the first preset position in the next operation will be determined. The velocity relationship is: v11 = (1 - y1) × v1, when 2% ≤ y1 ≤ 5%; v11=v1, when 0≤y1<2%; Therefore, during the process of slowly and uniformly lifting and transporting the precast steel box girder from its initial position to the first preset position, the tension distribution and angular deviation of the precast steel box girder are continuously monitored, and the posture of the precast steel box girder is adjusted in a timely manner to ensure that the precast steel box girder is transported to the first preset position smoothly and accurately. After being transported to the first preset position, the tension distribution, angular deviation, and position of the precast steel box girder are detected and adjusted accordingly to ensure the subsequent hoisting construction of the precast steel box girder. This reduces the errors generated during the lifting and transportation of the precast steel box girder from its initial position to the first preset position, and ensures that the hoisted precast steel box girder is installed with precise posture and position during construction. Furthermore, when hoisting the precast steel box girder again, the initial speed can be set based on the previously completed construction, which increases the convenience of multiple hoisting of the precast steel box girder, speeds up the hoisting process, reduces hoisting errors, and completes the construction more quickly, safely, and accurately.

[0032] Specifically, an embodiment for determining whether the posture and position of the precast steel box girder are stable during the process of lifting it horizontally from the first preset position to the second preset position and after reaching the second preset position, and for correcting errors: The second phase of the hoisting and horizontal transport process includes, During the process of translating and transporting the precast steel box girder from the first preset position to the second preset position, the main crane and the auxiliary crane lift the precast steel box girder from the first preset position to the second preset position. The control unit monitors and corrects the dynamic load distribution error of the precast steel box girder and the angular offset of the tilt sensor in real time. At the same time, it periodically detects the position of multiple measuring points on the precast steel box girder and corrects the displacement speed. The frequency, interval, or displacement speed of periodic testing is determined based on the angle and tension distribution at the end of the process of lifting and transporting the precast steel box girder from its initial position to the first preset position. The frequency, interval, or displacement velocity are determined a second time based on the location of the movement. The initial inspection interval is set to T2 during the process of translating and transporting the precast steel box girder from the first preset position to the second preset position. The estimated number of inspections required under the initial inspection interval is n2. The first translation stage is defined as n² / 2 (rounded up), and the first translation stage is performed for the duration of the initial detection interval T². The remaining distance is used as the basis for the second translation stage, which is performed with variable intervals. Among them, the interval duration of the variable interval is related to the remaining distance; within a certain range, the shorter the remaining distance, the shorter the detection interval.

[0033] The actual detection interval during the process of lifting and transporting the precast steel box girder from its initial position to the first preset position is set to T21. The relationship between the initial detection interval T2 and the actual detection interval T21 is: T2 / T21=1 / (1-y1) The preset speed for transporting the precast steel box girder from the first preset position to the second preset position is set as v2, and the initial speed for transporting the precast steel box girder from the first preset position to the second preset position is set as v21. After periodically checking the angle and tension distribution of the steel box girder during transportation, the speed of transporting the precast steel box girder is adjusted, and the adjusted speed is set as v22. The relationship between the initial velocity and the preset velocity is: v21 = (1-y1) × v2; Let y2 be the dynamic load distribution error during the process of lifting and transporting the precast steel box girder from its initial position to the first preset position, and let x2 be the angular offset. The relationship between the adjusted speed and the preset speed is: v22 = (1-y2) × v21; During the process of translating and transporting the precast steel box girder from the first preset position to the second preset position, after the main crane and the auxiliary crane lift the precast steel box girder from the first preset position to the second preset position, the control unit determines and adjusts the dynamic load distribution error of each tension sensor on the precast steel box girder; the control unit determines and adjusts the angular offset of each tilt sensor on the precast steel box girder; and the control unit determines and adjusts the actual stopping position of the precast steel box girder relative to the preset first position.

[0034] After the precast steel box girder is hoisted to the first preset position, its attitude and position are adjusted. Based on the deviation between the attitude and position of the precast steel box girder after adjustment and the ideal state, the initial preset periodic detection interval and initial displacement speed during the translation and transportation process are adjusted to overcome the deviation generated during the translation and transportation of the precast steel box girder from the first preset position to the second preset position. By monitoring the angular offset and tension distribution of the precast steel box girder in real time during the translation and transportation process, the attitude is adjusted in real time. Combined with periodic detection of the position deviation of the precast steel box girder and adjustment of the displacement speed, the interference of external forces on the precast steel box girder during the translation and transportation process is overcome, ensuring that the precast steel box girder can be hoisted to the designated position smoothly and accurately within the allowable error range according to the simulated path, and thus carry out smooth and accurate hoisting construction.

[0035] Specifically, an embodiment for determining whether the attitude and position of the precast steel box girder are stable during the process of lowering it from the second preset position to the target position and after it reaches the target position, and for correcting errors: The process of decentralization and transportation includes, During the process of lowering and transporting the precast steel box girder from the second preset position to the target position, the main crane and the auxiliary crane monitor and correct the dynamic load distribution error of the precast steel box girder and the angular offset of the tilt sensor in real time. At the same time, the control unit periodically detects the position of multiple measuring points on the precast steel box girder and corrects the displacement speed. The frequency, interval, or displacement speed of periodic testing is determined based on the angle and tension distribution at the end of the process of translating and transporting the precast steel box girder from the first preset position to the second preset position. The frequency, interval, or displacement velocity are determined a second time based on the location of the movement. The initial inspection interval is set to T3 during the process of translating and transporting the precast steel box girder from the first preset position to the second preset position. The estimated number of inspections n3 is calculated based on the initial inspection interval. The first translation stage is defined as n3 / 2 (rounded up), and the first translation stage is performed for a duration of the initial detection interval T3. The remaining distance is used as the basis for the second translation stage, which is performed with variable intervals. Among them, the interval duration of the variable interval is related to the remaining distance; within a certain range, the shorter the remaining distance, the shorter the detection interval.

[0036] The actual detection interval during the process of lifting and transporting the precast steel box girder from its initial position to the first preset position is set to T31. The relationship between the initial detection interval T3 and the actual detection interval T31 is: T31 / T3 = 1 / (1-y2); The preset speed for transporting the precast steel box girder from the second preset position to the target position is set to v3, and the initial speed for transporting the precast steel box girder from the second preset position to the target position is v31. After periodically checking the angle and tension distribution of the steel box girder during transportation, the speed of transporting the precast steel box girder is adjusted, and the adjusted speed is set to v32. The relationship between the initial velocity and the preset velocity is: v31 = (1-y2) × v3; Let y3 be the dynamic load distribution error during the process of lifting and transporting the precast steel box girder from its initial position to the first preset position, and let x3 be the angular offset. The relationship between the adjusted speed and the preset speed is: v32 = (1-y3) × v31; During the process of lowering and transporting the precast steel box girder from the second preset position to the target position, after the main crane and the auxiliary crane have lowered the precast steel box girder from the second preset position to the target position, the control unit determines and adjusts the dynamic load distribution error of each tension sensor on the precast steel box girder; the control unit determines and adjusts the angular offset of each tilt sensor on the precast steel box girder; and the control unit determines and adjusts the actual stopping position of the precast steel box girder relative to the preset first position. After the precast steel box girder is hoisted to the second preset position, its attitude and position are adjusted. Based on the deviation between the adjusted attitude and position of the precast steel box girder and its ideal state, the initial preset periodic detection interval and initial displacement speed during the lowering and transportation process are adjusted to overcome the deviation generated during the transportation of the precast steel box girder from the first preset position to the second preset position. By monitoring the angular offset and tension distribution of the precast steel box girder in real time during the lowering and transportation process from the second preset position to the target position, the attitude is adjusted in real time. Combined with periodic detection of the position deviation of the precast steel box girder and adjustment of the displacement speed, the interference of external forces on the precast steel box girder during the lowering and transportation process is overcome, ensuring that the precast steel box girder can be hoisted to the designated position smoothly and accurately within the allowable error range according to the simulated path, and the hoisting construction is carried out smoothly and accurately. After the hoisting is completed, the position and attitude of the hoisted precast steel box girder are finely adjusted according to the actual construction requirements to complete the high-precision installation of the precast steel box girder.

[0037] Specifically, an embodiment for determining whether a vessel's position has deviated and overcoming the influence of external factors includes: using an anchoring system to control the vessel's stability on the sea surface; using a measurement system to measure the vessel's mooring position on the sea surface; using a propulsion system to propel the vessel to overcome displacement caused by wind and tides on the sea surface; using a cooperative control system to obtain the position information of the vessel moored on the sea surface measured by the measurement system; determining the operating state of the propulsion system; until the vessel's mooring position on the sea surface matches a preset position. Anchoring systems are used to stabilize and control ships on the sea surface; ensuring the stability of the ship's position while anchored on the sea surface, they include tension leg anchors, anchor chains, and connecting devices, providing basic restoring force through pretension. Tension leg anchoring systems balance the movement of the floating body through the pretension of steel cables or synthetic material cables. The stiffness design can reduce high-frequency vibrations, thereby absorbing some wind and tidal energy after the ship is anchored, buffering the hull and preventing displacement of the hull under external forces, which would affect the high-precision construction during the hoisting of precast steel box girders.

[0038] The measurement system is used to measure the ship's position on the sea surface, thereby monitoring the ship's position deviation in real time, which facilitates the precise hoisting of precast steel box girders.

[0039] The propulsion system is used to propel the ship's movement to overcome displacement caused by wind and tides on the sea surface; The collaborative control system is connected to the mooring system, measurement system, and propulsion system. After the collaborative control system obtains the position information of the ship's mooring on the sea surface from the measurement system, when the position information of the ship's mooring on the sea surface changes, the collaborative control system controls the propulsion system to move the ship to overcome the displacement of the ship's mooring on the sea surface caused by wind and tides, so as to ensure that the ship's mooring position on the sea surface is consistent with the preset position.

[0040] By overcoming the external forces exerted on the ship by the external environment, the ship is ensured to remain in an ideal position within the allowable error range. This, in turn, ensures the precise positioning of the crane used for lifting precast steel box girders at sea. Furthermore, with the ship in a precise position, the ship can perform precise attitude control and precise lifting operations on multiple precast steel box girders.

[0041] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for controlling the posture accuracy of precast steel box girders during offshore hoisting, characterized in that, include, Prepare for the hoisting of precast steel box girders; The main and auxiliary cranes are synchronously controlled to lift and transport the precast steel box girder from the initial position to the first preset position. The stress of each sling and the degree of inclination of the precast steel box girder when it is in the first preset position are detected to redetermine the working mode of the main and auxiliary cranes, or to determine the working status of each sling. Determining the working modes of the main and auxiliary cranes includes determining the translational displacement speed for transporting the precast steel box girder from the first preset position to the second preset position; Based on the determined translational displacement speed, the main crane and auxiliary crane are controlled to move the precast steel box girder to the second preset position. The attitude and position of the precast steel box girder during the movement are periodically detected to determine the working mode of the main crane and auxiliary crane, or to determine the working status of each sling. The periodic inspection intervals vary depending on the position of the precast steel box girder during its movement.

2. The method for controlling the posture accuracy of offshore precast steel box girder hoisting according to claim 1, characterized in that, The attitude of the precast steel box girder is determined based on the stress conditions of each suspender cable, including: The control unit acquires data from each tension sensor used to detect the tension between the slings connected to the main crane and the auxiliary crane and the lugs of the precast steel box girder, and determines the dynamic load distribution error at the corresponding points of each tension sensor; The errors in the distribution of each dynamic load are assessed to determine their compliance. The working status of each sling is determined based on the number and location of non-compliant dynamic load distribution errors.

3. The method for controlling the posture accuracy of offshore precast steel box girder hoisting according to claim 2, characterized in that, The attitude of the precast steel box girder is determined based on its inclination angle, including: The control unit acquires the values ​​of the tilt sensors installed at the four corners of the top plate of the precast steel box girder and determines the angular offset of the tilt sensors. The angular offset of each tilt sensor is determined to confirm its qualification. The working status of each sling is determined based on the number and location of the non-compliant angular offsets.

4. The method for controlling the hoisting posture accuracy of precast steel box girders at sea according to claim 3, characterized in that, After the precast steel box girder reaches the first preset position, the actual position of the precast steel box girder is determined. include, The control unit acquires the actual coordinate data of several measurement points located at the midpoint of each edge of the rectangular top plate of the precast steel box girder, and determines the difference between the actual coordinate data of each measurement point and the three-dimensional coordinate data of the preset coordinate data. The differences in the three-dimensional coordinate data of each measurement point are judged to determine its compliance. Based on the number and location of the discrepancies in the non-compliant three-dimensional coordinate data, determine the working mode of the main and auxiliary cranes, or determine the working status of each sling.

5. The method for controlling the hoisting posture accuracy of precast steel box girders at sea according to claim 4, characterized in that, Based on the dynamic load distribution error and angular offset after the precast steel box girder is initially lifted and transported from its initial position to the first preset position, the lifting speed of the precast steel box girder for the next lifting and transport is re-determined.

6. The method for controlling the hoisting posture accuracy of precast steel box girders at sea according to claim 5, characterized in that, The initial interval for periodic detection is determined based on the posture and displacement velocity of the precast steel box girder after being repositioned at the first preset position. After completing the first translation stage, the variable interval for the second translation stage is determined. The first translation stage ends at the position after half of the translation stage from the first preset position to the second preset position, at the position where the initial detection interval is determined.

7. The method for controlling the hoisting posture accuracy of precast steel box girders at sea according to claim 6, characterized in that, The interval duration of the variable interval is related to the remaining distance; the shorter the remaining distance during the second translation phase, the shorter the detection interval.

8. The method for controlling the hoisting posture accuracy of precast steel box girders at sea according to claim 7, characterized in that, Based on the determination of the actual position of the precast steel box girder after the first translation stage, the displacement velocity of the precast steel box girder in the second translation stage is determined.

9. The method for controlling the hoisting posture accuracy of precast steel box girders at sea according to claim 8, characterized in that, The displacement velocity is determined based on the posture of the precast steel box girder after being redefined at the second preset position. The precast steel box girder is then lowered from the second preset position and transported to the target position. Periodic inspections are conducted during the movement, and the displacement velocity of the precast steel box girder before the next inspection is determined based on the determination of the posture and position of the precast steel box girder after each inspection.

10. The method for controlling the hoisting posture accuracy of precast steel box girders at sea according to claim 9, characterized in that, The working status of each sling includes the lowering length of each sling.

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