A sling anchor rotation angle measurement method, a jamming judgment method, and a pre-warning method

Abstract

The application discloses a kind of sling anchor device rotation angle measurement method, block determination method and early warning method, belong to bridge operation and maintenance technical field.It includes real-time measurement anchor device rotation angle;According to the rotation angle of anchor device of real-time measurement sudden jump rotation angle is determined;The sudden jump rotation angle is compared with preset rotation angle threshold, and the rotation block state of sling is determined;According to the pre-set graded early warning, the determination state of sling rotation block is early warned;The pre-set graded early warning includes: corresponding state one, state two, state three in turn rotation normal first-grade early warning, rotation block second-grade early warning, rotation lock third-grade early warning.The method for measuring the angle of sling anchor head can obtain data with high time resolution, avoid missing block information capture;Can accurately judge the block state, and can give block grading early warning for different degrees of block, provide effective basis for maintenance strategy selection.

Description

Technical Field

[0001] This invention relates to a method for measuring the rotation angle of a sling anchor, a method for judging jamming, and a method for early warning, belonging to the field of bridge operation and maintenance technology. Background Technology

[0002] Suspension bridges are currently the bridge structure with the strongest span capacity. They employ an efficient tension system to transfer bridge deck loads to the main towers and anchorages via suspenders and main cables. The suspenders, typically perpendicular to the bridge deck, directly connect the main girder and main cable, making them the most direct force-transmitting components. Because suspension bridges often have extremely large spans, the main girder experiences significant displacement along the bridge direction due to factors such as temperature and vehicle loads. Therefore, the suspenders are usually designed to rotate along the bridge direction to accommodate the displacement difference between the main girder and main cable (cable-girder displacement difference). The most common design uses forked anchor heads at the connection points between the suspenders and the main girder and main cable, achieving rotational performance through pin connections. However, prolonged reciprocating rotation of the suspenders leads to wear on the pins, increasing contact friction on the rotating surfaces. This can cause the anchor heads to become jammed or even stuck, increasing localized stress in the steel wires within the suspenders. Ultimately, this results in damage to the external protective structure and fatigue fracture of the steel wires, becoming a hidden danger threatening bridge safety. This phenomenon becomes more pronounced as the length of the sling decreases, because a shorter length means that the same cable beam displacement difference will result in a larger rotation angle, greater wear on the anchor head during daily rotation, and a higher likelihood of jamming. Therefore, there is an urgent need to invent a method that can detect or monitor the rotational performance of short slings and provide timely warnings of anchor head jamming in short slings.

[0003] There is no existing technology for detecting the obstruction of anchor head rotation. The obstruction or jamming of sling anchor head rotation usually has three forms: (1) slight obstruction of rotation, that is, the sling can still rotate back and forth with temperature and vehicle load, but at certain times, due to the accumulation of obstruction friction, there will be a sudden rotation jump. The angle of this sudden jump rotation is relatively small compared with the rotation angle caused by vehicle load or daily temperature change; (2) large obstruction of rotation, although the sling can rotate back and forth with temperature and vehicle load, there is a large number of jump rotations during the rotation process, and the angle of the jump rotation is large compared with the rotation angle caused by vehicle load or daily temperature change; (3) the sling anchor head rotation is completely jammed, and it cannot rotate back and forth normally with temperature and vehicle load. Occasionally, due to the accumulation of friction over a long period of time, there will be a sudden rotation release, and the amount of rotation released will be greater than the rotation angle caused by temperature and vehicle load. The above-mentioned rotation obstruction phenomena cannot be accurately monitored by conventional inclinometers, mainly because the inclinometer has a low monitoring frequency and cannot capture the high-frequency reciprocating rotation caused by vehicle load, so it is easy to make a misjudgment. Therefore, there is an urgent need for a reliable detection and judgment method to fill this gap. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method for measuring the rotation angle of sling anchors, a method for judging jamming, and a method for early warning.

[0005] To solve the above-mentioned technical problems, the present invention is implemented using the following technical solution.

[0006] In a first aspect, the present invention discloses a method for measuring the rotation angle of a sling anchor, comprising:

[0007] Place the displacement gauge's pin against the side of the anchor fork lug; the point where the pin contacts the anchor fork lug is the measuring point.

[0008] Obtain the horizontal and vertical distances from the measuring point to the center of the anchor pin when the anchor is in a vertical position;

[0009] Collect displacement change data measured by displacement gauges when the anchor rotates;

[0010] The rotation angle of the anchor is calculated using the horizontal distance, vertical distance, and displacement change data.

[0011] Furthermore, the formula for calculating the rotation angle is:

[0012] ;

[0013] In the formula, θ is the rotation angle of the anchor, r is the horizontal distance from the measuring point to the center of the anchor pin, h is the vertical distance from the measuring point to the center of the anchor pin, y is the displacement change data, π is pi, and acos(·) is the inverse cosine function.

[0014] Secondly, the present invention discloses a method for determining the rotational obstruction of a sling, comprising:

[0015] The method for measuring the rotation angle of short cable anchorages in suspension bridges described in the first aspect is used to measure the rotation angle of the anchorages in real time.

[0016] The sudden jump rotation angle is determined based on the real-time measured rotation angle of the anchor, and the sudden jump rotation angle is the change in rotation angle within a set time period;

[0017] The sudden jump rotation angle is compared with a preset rotation angle threshold to determine the sling rotation jamming state.

[0018] Further, the step of comparing the sudden jump rotation angle with multiple different preset rotation angle thresholds to determine the sling rotation jamming state includes:

[0019] The rotation angle of the sling under vehicle load or daily temperature change is obtained, and the rotation angle of the sling under vehicle load or daily temperature change is determined as the rotation angle threshold.

[0020] If a sudden jump in rotation angle occurs within the target time period, and the sudden jump in rotation angle is not greater than the rotation angle of the sling under vehicle load or daily temperature change, then it is determined to be state one. State one is that the rotation of the sling has a small amount of obstruction or no obstruction.

[0021] If multiple sudden jump rotation angles occur within the target time period, and the sudden jump rotation angles are the same as or greater than but not exceed the preset range of the rotation angle of the sling under vehicle load or daily temperature change, then it is determined to be state two, and state two is that there is a lot of obstruction in the rotation of the sling.

[0022] If there is no sudden jump rotation angle within the target time period, or if there is a sudden jump rotation angle and the sudden jump rotation angle is greater than the rotation angle of the sling under vehicle load or daily temperature change and exceeds the preset range, then it is determined to be state three. State three is that the sling anchor head rotation is completely stuck or close to stuck.

[0023] Furthermore, the process of determining state one and state two includes:

[0024] Obtain displacement time history data Y, , This represents the 1st, 2nd, ..., nth data point in the displacement change data Y, and the timestamp T corresponding to each data point in the displacement change data Y. ,in, This represents the timestamp corresponding to the 1st, 2nd, ..., nth data point in the displacement change data Y, where n represents the length of the displacement time history data. y i+1 and y i These represent displacement change data. Y The Middle i +1 and the i One data point, t i+1 and t i These represent displacement change data. Y The Middle i +1 and the i The timestamp corresponding to each data point;

[0025] Calculate the first-order difference K based on the displacement time history data Y and the timestamp T. ,in, For the i-th first-order difference, ,in, The data sampling time interval, , i=1,2,….n-1;

[0026] When any If so, it is identified as a jump. This is the jump threshold;

[0027] Get the index M of all data that jump within the displacement time history data length. , For the 1st, 2nd, ..., mth index, The skip data corresponding to index M , , This refers to the jump data for the 1st, 2nd, ..., mth jump points;

[0028] Based on the skip data corresponding to index M The sliding window mean comparison method is used to filter the jump data. If multiple axis shift data are found within a set time, it is determined that the anchor head is stuck. Otherwise, it is determined that there is a small amount of sticking or no sticking.

[0029] Furthermore, the process of using a sliding window mean comparison to filter skipped data for axis-shifting data includes:

[0030] Set the sliding window size to L, and for each index point in M, calculate the mean of the data for a period of time before the jump point. , and the mean of data after a period of time following the jump point , ,when The jump point was determined to be axis-shifted data. Determine the threshold for the axis-shifted data. y i-L , y i-L+1 and y i-1 These represent displacement change data. Y The Middle i - L , i - L+ 1 and the i -1 data point, y i+1 , y i+2 and y i+L These represent displacement change data. Y The Middle i +1、 i +2 and the i + L Data.

[0031] Furthermore, determining the jump threshold includes:

[0032] Calculate the standard deviation of the difference result based on the first-order difference K. ,set up N is the jump threshold, where N is a positive integer;

[0033] The determination of the threshold for judging the tilt-shift data includes:

[0034] Polynomial fitting is applied to the L data points before and after the jump point to obtain the trend term. This trend term is then removed from the L data points before and after the jump point to obtain the remaining residuals for the first L data points. The remaining residuals of the last L data points Calculate the larger standard deviation of the remaining residuals. ,set up The threshold for tilt-shift judgment, where N is a positive integer. Let L be the standard deviation of the remaining residuals of the first L data points. Let L be the standard deviation of the remaining residuals for the next L data points.

[0035] Furthermore, the process of determining state three also includes:

[0036] When it is detected that the target anchor on the sling does not suddenly jump and rotate within the target time period, the rotation angle of the anchor at the other end of the sling within the set time period is obtained. The rotation angles of the anchors at both ends of the sling within the set time period are compared, and the anchor with the smaller rotation angle within the set time period is identified as the anchor that is completely stuck.

[0037] Thirdly, the present invention discloses a method for early warning of cable rotation jamming, comprising:

[0038] The determination state of sling rotation jamming is determined using the second aspect of the sling rotation jamming judgment method;

[0039] The system provides warnings based on the pre-set graded warnings for the determination of the sling rotation jamming status; the pre-set graded warnings include: a level one warning for normal rotation, a level two warning for rotation jamming, and a level three warning for rotation lockup, corresponding to states one, two, and three in sequence.

[0040] The beneficial effects achieved by this invention are as follows:

[0041] This invention uses a displacement gauge to measure the angle of the sling anchor head and a rotation conversion calculation method to measure the rotation angle of the sling anchor head. It can obtain data with high time resolution, thereby avoiding the capture of erroneous or missed information. It is easy to install, and the measurement time is relatively short. It can be used as both a detection and monitoring method.

[0042] This invention can accurately determine the jamming state and provide jamming grade warnings for different degrees of jamming, providing an effective basis for the selection of maintenance strategies. Attached Figure Description

[0043] Figure 1 This is a flowchart illustrating the present invention;

[0044] Figure 2 This is a schematic diagram of a fork-type sling;

[0045] Figure 3 This is a schematic diagram for converting the rotation angle of the anchorage;

[0046] Figure 4 It is a simplification Figure 3 A schematic diagram in mathematical form;

[0047] Figure 5 This is a daily data chart of the unblocked anchor head;

[0048] Figure 6 This is a daily data chart of the rotating locking anchor head;

[0049] Figure 7 This is a daily data chart showing the rotating and locking anchor head;

[0050] Figure 8 It is the result of the recognition at the moment of rotational jamming.

[0051] Figure 3 In the middle: 1. Anchor fork lug; 2. Displacement gauge; 3. Ejector pin. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0053] Example 1, as Figure 1 As shown in the figure, this embodiment introduces a method for measuring the rotation angle of a sling anchor, including:

[0054] like Figure 2 As shown, the sling anchor head is usually designed as a fork-ear type, that is, the main beam and main cable extend through the ear plate to provide the sling connection position. The sling anchor is designed as a fork-ear type and is connected to the fork-ear by a pin that passes through the ear plate.

[0055] The displacement gauge 2's pin 3 is placed against the side of the anchor fork lug 1. The point where the pin 3 contacts the anchor fork lug is the measuring point. The principle is as follows: a fixing device is installed on the lug plate, and the displacement gauge 2 base is fixed on the lug plate. The displacement gauge 2's pin 3 is placed against the side of the anchor fork lug 1. When the sling rotates, the tilt of the fork lug due to the rotation will cause the displacement count value to change. The measurement method is as follows: Figure 3 As shown;

[0056] Obtain the horizontal and vertical distances from the measuring point to the center of the anchor pin when the anchor is in a vertical position;

[0057] Collect displacement change data measured by displacement gauges when the anchor rotates;

[0058] The rotation angle of the anchor is calculated using the horizontal distance, vertical distance, and displacement change data.

[0059] The formula for calculating the rotation angle is:

[0060] ;

[0061] In the formula, θ is the rotation angle of the anchor, r is the horizontal distance from the measuring point to the center of the anchor pin, h is the vertical distance from the measuring point to the center of the anchor pin, y is the displacement change data, π is pi, and acos(·) is the inverse cosine function.

[0062] like Figure 4 As shown, the derivation process of the formula for calculating the rotation angle is as follows:

[0063] The two solid lines represent the perpendicular line from the center of the pin to its edge before rotation, and the two thick dashed lines represent the position of the perpendicular line from the center of the pin to its edge after rotation. Given that O is the center of the pin, and D and A are the displacement measurement points before and after rotation... , , , , ,beg .

[0064] Assumption Draw auxiliary lines ,but In △EAC,

[0065] ;

[0066] In △BOC, ,but ,have:

[0067] ;

[0068] Since the two equations are equal, we have:

[0069] ;

[0070] Simplifying, we get:

[0071] ;

[0072] According to the general solution formula of the quadratic equation, we can obtain... :

[0073] ;

[0074] Simplifying, we get:

[0075] ;

[0076] therefore:

[0077] ;

[0078] .

[0079] Example 2, based on the same inventive concept as Example 1, introduces a method for determining the rotational obstruction of a sling, including:

[0080] The rotation angle of the short cable anchorage of the suspension bridge is measured in real time based on the method for measuring the rotation angle of the anchorage as described in Example 1.

[0081] The sudden jump rotation angle is determined based on the real-time measured rotation angle of the anchor, and the sudden jump rotation angle is the change in rotation angle within a set time period;

[0082] The sudden jump rotation angle is compared with a preset rotation angle threshold to determine the sling rotation jamming state.

[0083] The sling rotation jamming state includes: State 1: Rotation is slightly jammed or not jammed, meaning the sling can rotate back and forth with temperature and vehicle load. Although at certain times, due to the accumulation of jamming friction, there may be sudden rotation jumps, the angle of these sudden jumps is relatively small compared to the rotation angle caused by vehicle load or daily temperature changes. Figure 5 As shown; State Two: Rotation is subject to significant resistance. Although the sling can rotate back and forth with temperature and vehicle load, there are numerous rotational jumps during the process, and the angles of these jumps are comparable to or larger than the rotation angles caused by vehicle load or daily temperature changes. Figure 6 As shown; State 3: The sling anchor head is completely jammed and cannot rotate normally with temperature and vehicle load. Occasionally, due to the accumulation of friction over a long period of time, it may suddenly release rotation, and the amount of rotation released will be much greater than the rotation angle caused by temperature and vehicle load, such as... Figure 7 As shown.

[0084] However, since vehicle loads can also cause sudden jumps in the rotation of the sling, the occurrence of jamming cannot be simply determined by the jump in data. Therefore, based on the jamming classification according to the degree of sling jamming mentioned above, two jamming judgment criteria are proposed to distinguish the above three states, thereby identifying the occurrence and degree of jamming.

[0085] Criterion 1: Method for judging axis-shift jump in anchor head rotation data:

[0086] To distinguish between state one and state two, a method for judging the axis-shift jump in anchor head rotation data is proposed. Assume the obtained displacement change time history data measured by the anchor head displacement gauge is as follows: The timestamp corresponding to each data point is: ,in This represents the length of the time-history data.

[0087] First, the finite difference method is used to determine the locations where the data shows a rapid increase or decrease, that is, the first difference of the data is calculated. , ,here The data sampling time interval. When any If the data shows a rapid increase or decrease, it is considered a jump. Here, the threshold can be set to 5 times the standard deviation of the difference results. std represents the standard deviation calculation operator.

[0088] Secondly, after identifying the data jump locations, it is necessary to eliminate data fluctuations caused by vehicles or other noise, and identify data axis shifts. Let's assume the index of the identified jump data point is... The corresponding jump data is This paper proposes using a sliding window mean comparison method to remove skipped data. Specifically, the difference between the mean of the data for a period before and after the skip point must be greater than a threshold. This indicates that the data has not returned to its normal fluctuation range after the skip point, constituting a data shift, thus eliminating short-term data fluctuations caused by vehicle load. The sliding window size is defined as... For each The index point is used to calculate the mean of the data for a period of time before the jump point. and the mean of data after a period of time following the jump point ,when If the data is not properly aligned, it is considered axis-shifted data. Here, the threshold can be set to 5 times the standard deviation of the residual after detrending. This includes: applying a polynomial fit to the L data points before and after the jump point to obtain the fitted curve, i.e., the trend term; and removing this trend term from the L data points before and after the jump point to obtain the residual of the first L data points. The remaining residuals of the last L data points Calculate the larger standard deviation of the remaining residuals. ,set up Threshold for axis shift judgment, Let L be the standard deviation of the remaining residuals of the first L data points. Let L be the standard deviation of the remaining residuals for the next L data points. Using the above method, abnormal jump points with numerous bottlenecks are identified, such as... Figure 8 As shown.

[0089] Finally, to avoid misidentification, if the number of times the data shift is identified more than 3 times per day, it is considered that the anchor head has experienced normalized jamming; otherwise, the result is considered to be a misidentification or that the number of jamming events is too small to be ignored.

[0090] Criterion 2: Method for determining complete jamming of anchor head rotation:

[0091] To distinguish between state two and state three, and also to address the situation where, when the anchor head is completely stuck, the data fluctuates within a very small range and it is difficult to detect a shift in the axis, making it difficult to determine the first criterion, a method for comparing the data of the upper and lower anchor heads is proposed.

[0092] Because the suspender cable has upper and lower anchor heads, the jamming states of the upper and lower anchor heads often differ. This is due to the difference in stiffness between the main cable and the main beam. The main cable is more flexible, and the rotational internal force of the anchor head can be released through the displacement of the main cable, thereby reducing wear on the anchor head pin. The main beam has greater stiffness, and the vehicle load is directly transmitted to the lower anchor head through the main beam, resulting in greater rotational wear on the anchor head and making it more prone to jamming. Therefore, the jamming of a particular anchor head can be identified by comparing the range of fluctuation in the hourly rotation data of the upper and lower anchor heads.

[0093] Example 3, based on the same inventive concept as Example 2, introduces a method for early warning of cable rotation jamming, including:

[0094] Based on the determination status of the sling rotation data, the degree of jamming is graded and a warning is issued. Three levels of warning are set: Level 1 warning for normal rotation, Level 2 warning for jamming, and Level 3 warning for locked rotation. These represent three degrees of jamming: no jamming, minor jamming, and severe jamming, respectively. In this embodiment, the Level 1 warning for normal rotation, Level 2 warning for jamming, and Level 3 warning for locked rotation are indicated by LED lights. Level 1 is solid green, Level 2 is solid yellow, and Level 3 is flashing red. Warning notifications can also be sent via the network.

[0095] First, displacement gauges are installed to acquire the rotational displacement time history data of the upper and lower anchor heads of the target sling. Second, the acquired data is processed according to Criterion Two. If the data of any anchor head relative to the data of another anchor head satisfies Criterion Two, then that anchor head is considered to be rotationally locked, and a rotational lock-up warning is issued. Otherwise, Criterion One is used to process the anchor head data separately. If the data of any anchor head satisfies Criterion One, then that anchor head is considered to be rotationally obstructed, and a rotational obstruction warning is issued; otherwise, it is identified as a normally rotating anchor head.

[0096] The anchor head rotation problem identification system proposed in this embodiment, with its two sets of judgment criteria and three-level early warning response, first uses the difference method to analyze the locations of rapid data growth or decline to identify data jump points. Then, the sliding window averaging method is used to determine the change in the average data before and after the jump point, judging whether the jump exhibits axis shifting characteristics, thereby identifying sling jamming. By comparing data from different anchor head rotation angles, different degrees of anchor head damage, ranging from slight jamming to severe jamming, can be identified, thus providing different early warnings and offering data support for maintenance.

[0097] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0098] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0099] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0100] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0101] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the resistance to rotation of a sling, characterized in that, include: The rotation angle of the anchor is measured in real time based on the method for measuring the rotation angle of the sling anchor. The method for measuring the rotation angle of the sling anchor includes: placing the pin of the displacement gauge against the side of the anchor fork lug, with the point where the pin contacts the anchor fork lug as the measuring point; and obtaining the horizontal and vertical distances from the measuring point to the center of the anchor pin shaft when the anchor is in a vertical state. Displacement change data measured by a displacement gauge is collected when the anchor rotates; the rotation angle of the anchor is calculated using the horizontal distance, the vertical distance, and the displacement change data; the formula for calculating the rotation angle is: ； In the formula, θ is the rotation angle of the anchor, r is the horizontal distance from the measuring point to the center of the anchor pin, h is the vertical distance from the measuring point to the center of the anchor pin, y is the displacement change data, π is pi, and acos(·) is the inverse cosine function. The rotation angle of the anchor is measured in real time and then processed to determine whether there is a sudden jump in data. If so, the sudden jump rotation angle is determined. The sudden jump rotation angle is the change in rotation angle within a set time. The sudden jump rotation angle is compared with a preset rotation angle threshold to determine the sling rotation jamming state, including: The rotation angle of the sling under vehicle load or daily temperature change is obtained, and the rotation angle of the sling under vehicle load or daily temperature change is determined as the rotation angle threshold. If a sudden jump in rotation angle occurs within the target time period, and the sudden jump in rotation angle is less than the rotation angle of the sling under vehicle load or daily temperature change, then it is determined to be state one. State one is that the rotation of the sling has a small amount of obstruction or no obstruction. If multiple sudden jump rotation angles occur within the target time period, and the sudden jump rotation angles are the same as or greater than but not exceed the preset range of the rotation angle of the sling under vehicle load or daily temperature change, then it is determined to be state two, and state two is that there is a lot of obstruction in the rotation of the sling. If there is no sudden jump rotation angle within the target time period, or if there is a sudden jump rotation angle and the sudden jump rotation angle is greater than the rotation angle of the sling under vehicle load or daily temperature change and exceeds the preset range, then it is determined to be state three. State three is that the sling anchor head rotation is completely stuck or close to stuck.

2. The method for determining the resistance to sling rotation according to claim 1, characterized in that, The process of determining state one and state two includes: Obtain displacement time history data Y, , This represents the 1st, 2nd, ..., nth data point in the displacement change data Y, and the timestamp T corresponding to each data point in the displacement change data Y. ,in, This represents the timestamp corresponding to the 1st, 2nd, ..., nth data point in the displacement change data Y, where n represents the length of the displacement time history data. Calculate the first-order difference K based on the displacement time history data Y and the timestamp T. ,in, For the i-th first-order difference, ,in, The data sampling time interval, , i=1,2,….n-1, y i+1 and y i These represent displacement change data. Y The Middle i +1 and the i One data point, t i+1 and t i These represent displacement change data. Y The Middle i +1 and the i The timestamp corresponding to each data point; When any If so, it is identified as a jump. This is the jump threshold; Get the index M of all data that jump within the displacement time history data length. , For the 1st, 2nd, ..., mth index, The skip data corresponding to index M Represented as: , This refers to the jump data for the 1st, 2nd, ..., mth jump points; Based on the skip data corresponding to index M The sliding window mean comparison method is used to filter the jump data for axis shifting data. If multiple axis shifting data are found within a set time, it is determined that the anchor head is stuck. Otherwise, it is determined that there is a small amount of sticking or no sticking.

3. The method for determining the resistance to sling rotation according to claim 2, characterized in that, The process of filtering skipped data using the sliding window mean comparison method includes: Set the sliding window size to L, and for each index point in index M, calculate the mean of the data for a period of time before the jump point. , and the mean of data after a period of time following the jump point , ,when The jump point was determined to be axis-shifted data. Determine the threshold for the axis-shifted data. y i-L , y i-L+1 and y i-1 These represent displacement change data. Y The Middle i - L , i - L+ 1 and the i -1 data point, y i+1 , y i+2 and y i+L These represent displacement change data. Y The Middle i +1、 i +2 and the i + L Data.

4. The method for determining the resistance to sling rotation according to claim 2, characterized in that, The determination of the jump threshold includes: Calculate the standard deviation of the difference result based on the first-order difference K. ,set up N is the jump threshold, where N is a positive integer; The determination of the threshold for judging the tilt-shift data includes: Polynomial fitting is applied to the L data points before and after the jump point to obtain the trend term. This trend term is then removed from the L data points before and after the jump point to obtain the remaining residuals for the first L data points. The remaining residuals of the last L data points Calculate the larger standard deviation of the remaining residuals. ,set up Threshold for axis shift determination Let L be the standard deviation of the remaining residuals of the first L data points. Let L be the standard deviation of the remaining residuals for the next L data points.

5. The method for determining the resistance to sling rotation according to claim 2, characterized in that, The process of determining state three also includes: When it is detected that the target anchor on the sling does not suddenly jump and rotate within the target time period, the rotation angle of the anchor at the other end of the sling within the set time period is obtained. The rotation angles of the anchors at both ends of the sling within the set time period are compared, and the anchor with the smaller rotation angle within the set time period is identified as the anchor that is completely stuck.

6. A method for early warning of cable rotation jamming, characterized in that, include: The determination state of sling rotation jamming is determined using the sling rotation jamming determination method described in claim 1; The system provides early warnings based on pre-set tiered warning systems to determine the jamming status of the sling rotation. The pre-set hierarchical warning system includes: a level one warning for normal rotation, a level two warning for rotation jamming, and a level three warning for rotation lockup, corresponding to states one, two, and three in sequence.

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