Gantry crane moment limit protection method and system based on current verification

Abstract

The invention relates to the technical field of hoisting machinery safety monitoring and control, and particularly discloses a portal crane moment limit protection method and system based on current verification. Real-time detection signals of a hoisting mechanism are obtained through a moment sensor, and a three-axis accelerometer is arranged at the connecting position of a steel wire rope to obtain swing signals; analyzing a jitter interference factor based on the steel wire rope jitter displacement, and judging the accuracy of a detection signal; on the premise that the signal is accurate, operation state detection of primary mechanical power calculation is carried out, then secondary operation state detection is carried out by combining the rated working current of the lifting frequency converter calculated by the detection signal and the real-time working current collected by the PLC, and the lifting mechanism is controlled to operate according to the detection result. Through multi-dimensional signal fusion and secondary verification, the detection precision and the overload judgment reliability are improved, the overload operation of equipment can be effectively prevented, and the operation safety of the crane and the service life of the equipment are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of safety monitoring and control technology for lifting machinery, and more specifically, to a method and system for limiting and protecting the torque of a gantry crane based on current verification. Background Technology

[0002] Existing gantry cranes typically use torque limiters for overload protection. This usually involves detecting wire rope tension using weight sensors positioned at the wire rope's stress points, and boom pitch angle using angle sensors positioned at the boom hinge points. The torque limiter's main unit calculates the actual weight and operating radius based on these parameters and compares this to the design safety curve to determine if an overload has occurred. When the torque limiter detects an overload, it outputs a stop signal to the PLC control system. The PLC then implements overload protection by blocking the inverter's operating commands. While this existing overload protection method is relatively mature in engineering applications, several significant technical issues remain.

[0003] While conventional gantry crane hoisting mechanism operation control includes overload protection, this protection relies on the weight detection of a torque limiter. The detection target is the hoisting wire rope, which experiences shaking and vibration during operation, causing fluctuations and instability in the detected data. Furthermore, the weight detection sensor is located a considerable distance from the torque limiter's main unit, and the long signal transmission line is susceptible to interference from other power cables. Therefore, the accuracy of the overload protection signal is affected, resulting in significant deficiencies in the protection function. These factors can lead to false alarms or missed alarms in existing torque limiters: when the detected weight is too high, the torque limiter may prematurely output an overload signal, causing a false alarm and abnormal shutdown of the hoisting mechanism; when the detected weight is too low, the overload may fail to alarm in time, allowing the hoisting mechanism to continue operating under overload conditions, posing a serious safety hazard.

[0004] Therefore, it is necessary to provide a gantry crane torque limiting protection method and system based on current verification to solve the above-mentioned technical problems. In order to solve the above problems, a technical solution is provided. Summary of the Invention

[0005] To overcome the aforementioned deficiencies of the prior art, this invention provides a gantry crane torque limiting protection method and system based on current verification. This addresses the problem that existing torque limiters are highly dependent on wire rope tension signals and are easily affected by jitter and electromagnetic interference, resulting in unstable and inaccurate overload protection signals, and potential safety hazards such as false alarms and missed alarms.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A gate operator torque limiting protection method based on current verification includes the following steps: The detection signal output by the torque sensor is obtained in real time, and the swing signal is obtained in real time by arranging a triaxial accelerometer at the wire rope connection. The detection signal and the swing signal are preprocessed. Based on the swing signal, the jitter displacement variable of the wire rope is tracked, the jitter interference factor of the wire rope is analyzed, and the accuracy of the output detection signal is determined by correlating the detection signal. Once the accuracy of the detection signal is determined to meet the standard, a single operational status test of the hoisting mechanism is performed based on the detection signal. The rated operating current of the hoisting frequency converter is obtained based on the detection signal. The real-time operating current of the hoisting frequency converter is read through the communication cable between the PLC system and the frequency converter. Based on the rated operating current and the real-time operating current, the secondary operating status detection of the hoisting mechanism is performed. The operation of the hoisting mechanism is controlled based on the results of secondary operation status detection.

[0007] As a further aspect of the present invention, the swing signal includes a first swing signal, a second swing signal, and a third swing signal.

[0008] As a further aspect of the present invention, a first swing signal of the wire rope during the lifting process is acquired in real time by arranging a triaxial accelerometer at the wire rope connection, and a first swing signal sequence is formed; a second swing signal of the wire rope within a fixed period before lifting is acquired in real time by arranging a triaxial accelerometer at the wire rope connection, and a second swing signal sequence is formed; a third swing signal of the wire rope during a preset normal lifting process is acquired in real time by arranging a triaxial accelerometer at the wire rope connection, and a third swing signal sequence is formed.

[0009] As a further aspect of the present invention, the jitter displacement variable of the wire rope is tracked based on the swing signal, the jitter interference factor of the wire rope is analyzed, and the accuracy of the output detection signal is determined by correlating the detection signal. Specific steps include: Obtain a first swing signal sequence and a second swing signal sequence, and determine a first interference coefficient based on the correlation matching of the first swing signal and the second swing signal; Obtain the first swing signal sequence and the third swing signal sequence, and determine the second interference coefficient based on the correlation matching of the first swing signal and the third swing signal; The sum of the first interference coefficient and the second interference coefficient is used to output the vibration interference factor of the wire rope. The jitter interference factor is compared with a preset interference threshold. If the jitter interference factor is greater than or equal to the preset interference threshold, the accuracy of the first detection signal is determined to be non-compliant with the standard. If the jitter interference factor is less than the preset interference threshold, the accuracy of the first detection signal is determined to be compliant with the standard.

[0010] As a further aspect of the present invention, a first swing signal sequence and a second swing signal sequence are obtained, and a first interference coefficient is determined based on the correlation matching of the first swing signal and the second swing signal. The specific steps are as follows: Extract the first swing signal sequence to plot the spectrum of the first signal, and extract the second swing signal sequence to plot the spectrum of the second signal. Image association matching is performed based on the spectrum of the first signal and the spectrum of the second signal to output the first association value, and the first interference coefficient is obtained based on the first association value.

[0011] As a further aspect of the present invention, a first swing signal sequence and a third swing signal sequence are obtained, and a second interference coefficient is determined based on the correlation matching of the first swing signal and the third swing signal. The specific steps are as follows: Extract the first swing signal sequence and plot the spectrum of the first signal, and extract the third swing signal sequence and plot the spectrum of the third signal; Image association matching is performed based on the spectrum of the first signal and the spectrum of the third signal to output the second association value, and the second interference coefficient is obtained based on the second association value.

[0012] As a further aspect of the present invention, when it is determined that the accuracy of the detection signal meets the standard, a single operational status detection of the hoisting mechanism is performed based on the detection signal. The specific steps are as follows: Real-time acquisition of detection signals and construction of detection signal sequences ,in Let be the detection signal at time t. for The detection signal at any moment, The inspection time during the lifting process, For the i-th time interval, For the detection time interval, This represents the total number of time intervals during the lifting process. ,in, for The lifting tonnage at any given moment, for The tilt angle of the boom at all times. for The lifting speed at any given moment; Extract the lifting tonnage and lifting speed at each detection moment, and calculate the output power of the hoisting mechanism based on the lifting tonnage and lifting speed. ,in, for The output power of the lifting mechanism at all times. Design coefficient, for The lifting tonnage at any given moment, for The lifting speed at any given moment, For mechanical efficiency; The hoisting mechanism's operating status is checked based on its output power. The output power of the hoisting mechanism is compared with a preset output power threshold. If the output power of the hoisting mechanism is greater than or equal to the preset output power threshold, an overload signal awaiting review is output. If the output power of the hoisting mechanism is less than the preset output power threshold, a no-overload signal awaiting review is output.

[0013] As a further aspect of the present invention, the rated operating current of the lifting frequency converter is obtained based on the detection signal, and the specific steps are as follows: Formula for calculating the output power of the hoisting mechanism and the formula for calculating electrical power. ,in, for Constant electrical power for Operating voltage at all times for Constant operating current; Depend on ,get Therefore, we get That is, under the conditions of rated lifting tonnage and lifting speed, the rated operating current is a fixed value.

[0014] As a further aspect of the present invention, the real-time operating current of the hoisting inverter is read through the communication cable between the PLC system and the inverter. Based on the rated operating current and the real-time operating current, a secondary operating status detection of the hoisting mechanism is performed. The specific steps are as follows: When an overload signal awaiting review is output, the rated operating current is compared with the real-time operating current. If the rated operating current is less than the real-time operating current, the hoisting mechanism is in a non-overload state and continues to operate normally; otherwise, the hoisting mechanism is in an overload state and stops operating. When the output shows no overload signal pending review, the rated operating current is compared with the real-time operating current. If the rated operating current is greater than or equal to the real-time operating current, an overload signal is output to determine that the hoisting mechanism is in an overload state, and the hoisting mechanism stops operating. Conversely, if the rated operating current is not greater than or equal to the real-time operating current, the hoisting mechanism is in a non-overload state and continues to operate normally.

[0015] A gantry crane torque limiting protection system based on current verification, the system includes a signal acquisition and processing module, a wire rope jitter interference analysis module, a primary operation status detection module, a secondary operation status detection module, and an operation control decision module; The signal acquisition and processing module is used to acquire the detection signal output by the torque sensor in real time. It acquires the swing signal in real time by arranging a triaxial accelerometer at the wire rope connection and preprocesses the detection signal and the swing signal. The wire rope vibration interference analysis module is used to track the vibration displacement variable of the wire rope based on the swing signal, analyze the vibration interference factor of the wire rope, and determine the accuracy of the output detection signal by correlating the detection signal. The primary operation status detection module is used to perform a primary operation status detection of the hoisting mechanism based on the detection signal when the accuracy of the detection signal is determined to meet the standard. The secondary operation status detection module is used to obtain the rated operating current of the hoisting frequency converter based on the detection signal, read the real-time operating current of the hoisting frequency converter through the communication cable between the PLC system and the frequency converter, and perform secondary operation status detection of the hoisting mechanism based on the rated operating current and the real-time operating current. The operation control decision module controls the operation of the hoisting mechanism based on the results of the secondary operation status detection.

[0016] The technical effects and advantages of this invention, a gantry crane torque limiting protection method and system based on current verification, are as follows: This invention acquires real-time detection signals of the hoisting mechanism using a torque sensor, and obtains swing signals using a triaxial accelerometer placed at the wire rope connection. Based on the wire rope jitter displacement analysis, the jitter interference factor is determined to assess the accuracy of the detection signals. Under the premise of accurate signals, a first-stage mechanical power calculation and operational status detection is performed. Then, a second-stage operational status detection is performed, combining the rated operating current of the hoisting inverter calculated from the detection signals with the real-time operating current collected by the PLC. The hoisting mechanism is controlled according to the detection results. Through multi-dimensional signal fusion and secondary verification, not only is the detection accuracy and overload judgment reliability improved, but overload operation of the equipment is also effectively prevented, ensuring the safety of crane operation and extending equipment lifespan.

[0017] This invention utilizes multi-dimensional signal fusion from a torque sensor and a triaxial accelerometer to analyze wire rope vibration interference in real time. After confirming signal accuracy, it performs a mechanical power test and a secondary current verification, thereby accurately determining the operating status of the hoisting mechanism. This multi-level detection mechanism effectively reduces reliance on a single tension signal, filtering abnormal signals caused by wire rope vibration, electromagnetic interference, and other factors, avoiding false alarms or missed alarms due to the torque limiter's sole reliance on tension. This invention significantly improves the stability and accuracy of overload protection signals; reduces the risk of unnecessary equipment downtime and ensures the continuity of hoisting operations; enhances crane operating safety and extends equipment lifespan; and provides reliable safety assurance for high-load or complex operating environments, enabling intelligent monitoring and refined management. Attached Figure Description

[0018] Figure 1 A flowchart of a gate machine torque limiting protection method based on current verification is provided for an embodiment of the present invention; Figure 2 This is a system block diagram of a gantry crane torque limiting protection system based on current verification, provided for an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described technical solutions are only a part of this invention, and not all of it. All other technical solutions obtained by those skilled in the art based on the technical solutions of this invention without inventive effort are within the scope of protection of this invention.

[0020] like Figure 1 The diagram shown is a flowchart of a gate machine torque limiting protection method based on current verification provided by an embodiment of the present invention. Figure 1 The execution entity of the method shown can be a software and / or hardware device. The execution entity of this application can include, but is not limited to, at least one of the following: user equipment, network equipment, etc. User equipment can include, but is not limited to, computers, smartphones, personal digital assistants (PDAs), and the aforementioned electronic devices. Network equipment can include, but is not limited to, a single network server, a server group consisting of multiple network servers, or a cloud based on cloud computing consisting of a large number of computers or network servers. Cloud computing is a type of distributed computing, consisting of a super virtual computer composed of a group of loosely coupled computers. This embodiment does not limit this. Steps S1 to S5 are detailed as follows: Step S1: Obtain the detection signal output by the torque sensor in real time; obtain the swing signal in real time by arranging a triaxial accelerometer at the wire rope connection; and preprocess the detection signal and the swing signal. Step S2: Track the jitter displacement variable of the wire rope based on the swing signal, analyze the jitter interference factor of the wire rope, and determine the accuracy of the output detection signal by correlating the detection signal. Step S3: When it is determined that the accuracy of the detection signal meets the standard, perform a single operation status test of the hoisting mechanism based on the detection signal; Step S4: Obtain the rated operating current of the hoisting frequency converter based on the detection signal, read the real-time operating current of the hoisting frequency converter through the communication cable between the PLC system and the frequency converter, and perform secondary operation status detection of the hoisting mechanism based on the rated operating current and the real-time operating current. Step S5: Control the operation of the hoisting mechanism based on the secondary operation status detection results.

[0021] Preferably, the swing signal includes a first swing signal, a second swing signal, and a third swing signal.

[0022] Preferably, a triaxial accelerometer is arranged at the wire rope connection point to acquire the first swing signal of the wire rope in real time during the lifting process, and a first swing signal sequence is formed. , ,in, This is the first swing signal at time t. for The first swing signal at time, For the i-th time interval, For the detection time interval, This represents the total number of time intervals during the lifting process. This represents the first swing signal in the x-direction at time t. This represents the first oscillation signal in the y-direction at time t. This is the first oscillation signal in the z direction at time t; By arranging triaxial accelerometers at the wire rope connection points to acquire the second swing signal of the wire rope within a fixed period before lifting, a second swing signal sequence is formed. , ,in, This is the second swing signal at time u. for The second swing signal at time, For the j-th time interval, For the detection time interval, This represents the total number of time intervals during the lifting process. for The second swing signal in the x-direction at time x, for The second swing signal in the y-direction at time t, for The second swing signal in the z-direction at time z; By arranging triaxial accelerometers at the wire rope connection points, the third swing signal of the wire rope during the normal lifting process is acquired in real time, thus forming a third swing signal sequence. ,in, This is the third swing signal at time p. for The third swing signal at time , For the detection time interval, For the q-th time interval, To preset the total number of time intervals during the normal lifting process, for The third swing signal in the x-direction at time x, for The third swing signal in the y-direction at time t. for The third swing signal in the z-direction at time z.

[0023] In one embodiment of the present invention, to address the problem of wire rope vibration disturbing the weight detection signal during actual gantry crane lifting operations, a triaxial accelerometer is installed at the connection point between the wire rope and the hook to record the spatial acceleration changes of the wire rope under different working conditions in real time. To comprehensively identify interference sources and establish a reliable swing characteristic model, this embodiment collects three types of swing signals: swing signals during lifting, swing signals at rest before lifting, and reference swing signals under normal working conditions.

[0024] First, when the equipment begins lifting, the accelerometer collects the acceleration of the wire rope in three directions at fixed detection intervals, such as 10ms, recording this as the first swing signal. The signals from the entire lifting process are then sequenced chronologically, with each sampling point containing three-dimensional acceleration information. Second, to distinguish between "natural jitter noise" and "effective swing caused by the load," the hook is kept stationary for several seconds before the lifting action begins, for example, 5 seconds. The accelerometer simultaneously collects the second swing signal, forming a second swing signal sequence. This signal sequence typically includes background disturbances such as ambient wind and slight swaying of the steel structure, with amplitudes far lower than the actual swing signal during lifting, providing an important reference baseline for the environmental background noise of the wire rope. By comparing this signal with the first swing signal, the effective dynamics caused by the lifting action and environmental noise can be effectively separated.

[0025] In addition, to provide a standardized swing model for equipment operating under ideal, interference-free conditions, this embodiment also pre-records a third swing signal under rated load, stable weather conditions, and standard operating procedures, forming a reference swing signal sequence. This sequence is typically acquired during the initial installation and commissioning phase or periodic maintenance, and has good engineering benchmark significance, which can be used for long-term monitoring of equipment status changes. For example, when the hoisting motor is running smoothly, the frequency peak of the acceleration signal in certain directions should be stable within a fixed bandwidth. By comparing it with the third swing signal, it is possible to determine whether there are risks such as abnormal vibration, wire rope wear, or load eccentricity.

[0026] Finally, by correlating and analyzing the first, second, and third swing signals, the wire rope vibration interference coefficient can be calculated in real time, distinguishing between actual load changes and interference noise, and providing a reliable basis for subsequent weight signal verification and torque limiting protection. For example, if the first and second swing signals are highly consistent, while the second swing signal differs significantly from the first, it can be determined that the swing during lifting is caused by normal load. Conversely, if a large number of out-of-order signals that are highly similar to the second swing signal but deviate significantly from the third swing signal appear in the first swing signal, it indicates that the detection process may be affected by environmental interference or electromagnetic noise. In this case, the detection signal correction mechanism can be triggered to avoid false triggering of overload protection.

[0027] Preferably, the method involves tracking the jitter displacement variable of the wire rope based on the oscillation signal, analyzing the jitter interference factor of the wire rope, and correlating the detection signal to determine the accuracy of the output detection signal. Specific steps include: Obtain a first swing signal sequence and a second swing signal sequence, and determine a first interference coefficient based on the correlation matching of the first swing signal and the second swing signal; Obtain the first swing signal sequence and the third swing signal sequence, and determine the second interference coefficient based on the correlation matching of the first swing signal and the third swing signal; The sum of the first interference coefficient and the second interference coefficient is used to output the vibration interference factor of the wire rope. The jitter interference factor is compared with a preset interference threshold. If the jitter interference factor is greater than or equal to the preset interference threshold, the accuracy of the first detection signal is determined to be non-compliant with the standard. If the jitter interference factor is less than the preset interference threshold, the accuracy of the first detection signal is determined to be compliant with the standard.

[0028] In actual gantry crane operations, the wire rope experiences varying degrees of vibration during the lifting and pre-lifting phases. This vibration directly affects the tension output of the weight sensor, causing fluctuations in the torque limiter's detection signal. To effectively analyze the actual impact of wire rope vibration on the detection signal, this embodiment constructs a wire rope vibration interference factor based on the swing signal collected by a triaxial accelerometer, using displacement variable tracking and sequence correlation analysis methods, to determine the reliability of the weight detection signal.

[0029] First, after the lifting operation begins, the acceleration of the wire rope in three dimensions is recorded in real time, and a first swing signal sequence is constructed with a fixed sampling period. Simultaneously, during the static phase before the lifting action begins, a second swing signal sequence is acquired to reflect the natural disturbance state of the wire rope under no-load conditions. To assess whether the swing during the lifting process is caused by "real lifting" or "environmental noise," the first and second swing signal sequences are correlated and matched. For example, the temporal amplitude characteristics of the two sequences are compared using dynamic time warping, weighted Euclidean distance, or correlation coefficient methods. When the first swing signal sequence contains a large number of random jitter components similar to those in the second swing signal sequence, the matching result will show a high first interference coefficient, indicating that the current detected signal may be affected by environmental noise or external force disturbance.

[0030] Secondly, to further identify whether the current hoisting state deviates from the normal operating characteristics of the equipment, the first swing signal sequence is correlated and matched with the pre-recorded standard operating condition swing signal sequence and the third swing signal sequence. The third swing signal sequence reflects the typical swing pattern of the equipment under normal load and stable conditions. Therefore, if the matching degree between the first swing signal sequence and the third swing signal sequence is low, it indicates that there may be abnormal vibration of the wire rope, such as load sway, slight collision of the lifting device, abnormal dynamics caused by wire rope wear, etc. The second interference coefficient is obtained through matching calculation. The larger the value, the more obvious the deviation from the normal operating condition.

[0031] Then, the first interference coefficient and the second interference coefficient are superimposed to obtain a comprehensive wire rope vibration interference factor. This interference factor can comprehensively reflect two types of key deviations within a unified index: one from environmental or external noise, and the other from anomalies in the mechanical structure and the hoisting process itself, making the evaluation of the vibration interference factor more comprehensive and accurate. Finally, the vibration interference factor is compared with a preset interference threshold. If the interference factor is greater than or equal to the preset threshold, it indicates that the current wire rope vibration is sufficient to significantly affect the accuracy of the weight detection signal. The first detection signal output by the torque limiter will be determined to be unreliable and will be prevented from being used for subsequent hoisting status judgment to avoid false alarms causing accidental shutdowns or overload risks due to missed alarms. Conversely, when the interference factor is less than the threshold, it indicates that the current wire rope sway is within an acceptable range, the detection signal of the torque limiter is reliable, and it can be used as the input basis for subsequent primary and secondary operating status detection.

[0032] Through the above steps, this embodiment can evaluate the impact of wire rope vibration on weight detection in real time and dynamically under complex construction environments, effectively improve the stability and safety of torque limiting protection, avoid false alarms or missed alarms caused by interference in traditional single-signal weight detection methods, and improve the overall safety and reliability of gantry crane lifting.

[0033] Preferably, a first swing signal sequence and a second swing signal sequence are obtained, and a first interference coefficient is determined based on the correlation matching of the first swing signal and the second swing signal. The specific steps are as follows: Extract the first swing signal sequence Plot the spectrum of the first signal and the second oscillating signal sequence. Plot the spectrum of the second signal; Image association matching is performed based on the spectrum of the first signal and the spectrum of the second signal, and the first association value is output. The first interference coefficient is obtained based on the first correlation value. .

[0034] In this embodiment, in order to accurately identify whether the swing of the wire rope during the lifting process is caused by environmental interference rather than by actual load changes, frequency domain analysis is performed on the first swing signal sequence and the second swing signal sequence, and the first interference coefficient is calculated based on the similarity between the spectrum images. This can be realistically applied to the weight signal verification scenario of the gantry crane lifting mechanism.

[0035] First, when the hoisting mechanism starts and begins lifting the load, triaxial accelerometers located at the wire rope connection point collect the acceleration signals of the wire rope in three dimensions at fixed sampling intervals, thus forming the first swing signal sequence. For example, when the hoisting process lasts for 5 seconds with a sampling interval of 10ms, n=500 sampling points can be obtained. Simultaneously, before the hoisting action begins, the system keeps the hook stationary, and the accelerometers also collect the natural swing signal of the wire rope within the same sampling period, forming the second swing signal sequence I2. This sequence reflects background noise such as wind force, environmental disturbances, and the natural vibration of the steel structure.

[0036] Subsequently, Fast Fourier Transforms were performed on the first and second swing signals, respectively, yielding their corresponding spectra. The spectrum of the first signal mainly exhibits low-frequency, large-amplitude characteristics caused by load changes and the movement of the suspended load, while the spectrum of the second signal mainly exhibits high-frequency, weak-amplitude characteristics of random noise. For example, when lifting heavy objects, the main vibration frequency of the wire rope may be concentrated in the range of 1–3 Hz, while the natural jitter frequency in a stationary state may be dispersed in the range of 5–15 Hz with very small amplitude. The two spectra clearly reflect the differences in the frequency domain characteristics of the signals.

[0037] Next, an association matching operation is performed based on the spectral images. Specifically, the two spectral images are treated as two-dimensional data matrices. Using image similarity algorithms, such as structural similarity, normalized cross-correlation, or cosine similarity, the matching degree between the i-th frequency band of the first swing signal and the j-th frequency band of the second swing signal is calculated to obtain the corresponding association value. The association value is used to measure whether the energy distribution of the two signals is consistent in a specific frequency band. When the frequency characteristics of the first swing signal are significantly biased towards the vibration of the suspended load, while the second swing signal has typical noise characteristics, the image similarity between the two is low; conversely, if the first swing signal exhibits spectral fluctuations highly similar to the second swing signal in certain time periods, it can be determined that the signal in that segment may be affected by environmental interference.

[0038] Finally, the first interference coefficient is obtained by calculating all the first correlation values ​​according to a preset formula, which can quantify the degree of interference from static natural jitter in the current lifting signal. For example, when the first interference coefficient is close to 0, it indicates that the similarity between the first swing signal and the second swing signal is very low, indicating that the current lifting signal is highly reliable; while when the first interference coefficient is close to 1, it indicates that the first swing signal contains a large number of components similar to background interference, and the wire rope detection signal may have been affected by external disturbances and is not suitable for direct weight verification.

[0039] Through the above steps, this embodiment can accurately identify the background interference level of the wire rope based on frequency domain image matching, providing a reliable basis for the subsequent accurate judgment of the detection signal, effectively avoiding false alarms or missed alarms caused by wire rope vibration in traditional torque limiters, and improving the overall safety and stability of the gantry crane.

[0040] Preferably, a first swing signal sequence and a third swing signal sequence are obtained, and a second interference coefficient is determined based on the correlation matching of the first swing signal and the third swing signal. The specific steps are as follows: Extract the first swing signal sequence Plot the spectrum of the first signal and the sequence of the third oscillating signal. Plot the spectrum of the third signal; Image association matching is performed based on the spectrum of the first signal and the spectrum of the third signal, and a second association value is output. The second interference coefficient is obtained based on the second correlation value. .

[0041] In practical engineering, the third swing sequence of this invention is a reference swing data collected and saved in advance under "standard / normal lifting conditions," representing the typical spectral characteristics of the equipment under normal and standardized operating conditions; the first swing sequence is the swing data collected in real time during the current lifting process. By comparing the similarity between the two in the frequency domain, the deviation between the current operating condition and the reference operating condition can be quantified, thereby obtaining the second interference coefficient, which is used to determine whether the current swing is abnormal and to assist in judging the accuracy of the detection signal. The specific steps and engineering details are described below: First, data acquisition and preprocessing are performed. At the wire rope connection, a triaxial accelerometer collects the current lifting triaxial acceleration sequence at a uniform sampling interval. This sequence is then synthesized into an amplitude sequence to obtain the first swing sequence, and a previously saved "normal operating condition" third swing sequence is read and loaded. Both sequences undergo DC removal and bandpass filtering to remove gravity components and high-frequency noise. The triaxial signals are then either synthesized or processed separately and then weighted and fused, depending on specific requirements. Subsequently, the preprocessed first and third swing signals are segmented into frames, and each frame is windowed using a window function to obtain the amplitude spectrum vector for each frame. This yields the frame spectrum sets for the first and third sequences. To facilitate matching, each spectral vector should be normalized, and logarithmic scaling or amplitude smoothing can be used to enhance robustness.

[0042] In the spectral image association and matching stage, a spectral similarity value is calculated for each pair of frames. Commonly used and computationally efficient similarity metrics include cosine similarity, normalized cross-correlation, or structural similarity; cosine similarity is preferred, as its value typically ranges from 0 to 1. When finer-grained comparisons are required, similarities can be calculated separately along the three axes and then combined according to weights.

[0043] After obtaining all the second correlation values, the second interference coefficient is calculated. The calculation formula is as follows: first, calculate the average second correlation value of each reference frame with all current frames, then take the average to obtain the overall second correlation value, and finally obtain the second interference coefficient. If the second correlation value is close to 1, it indicates that the current swing is consistent with the reference height; otherwise, if the second correlation value is close to 0, it indicates a large deviation.

[0044] To facilitate engineering interpretation, empirical thresholds can be set, and numerical examples are provided: for example, setting a threshold range. This is considered to be consistent with normal operating conditions. This is considered a minor deviation; it is recommended to enable delayed confirmation or reduce sensitivity. This is considered a significant deviation, triggering an abnormal alarm and activating backup verification, such as overload judgment based on current or manual review. For example: If All were calculated Post-overall average similarity ,but This indicates that the current oscillation is close to the reference and can be considered normal; if ,but This indicates that the oscillation has significantly deviated from the normal range and requires further processing.

[0045] The recommendations and robustness measures include: for Perform extremum removal or replace the mean with the median to reduce the impact of single-frame noise; save multiple sets for different operating conditions. A benchmark is established and a matching benchmark is selected according to the operating conditions; in real-time systems, frame spectrum calculation and similarity calculation can be deployed on edge computing units to meet real-time requirements, and the original waveform, spectrum and... Values ​​are recorded for post-hoc analysis and threshold recalibration.

[0046] In summary, the above process involves sampling, preprocessing, frame-level spectrum analysis, pairwise similarity calculation, aggregation and averaging, and finally, selection. The second interference coefficient can be obtained in this way. It combines the threshold to determine the degree of deviation between the current swing and the normal operating condition, thereby providing a reliable and traceable basis for the accuracy assessment of the detection signal and subsequent safety control.

[0047] Preferably, when the accuracy of the detection signal is determined to meet the standard, a single operational status test of the hoisting mechanism is performed based on the detection signal. The specific steps are as follows: Real-time acquisition of detection signals and construction of detection signal sequences ,in Let be the detection signal at time t. for The detection signal at any moment, The inspection time during the lifting process, For the i-th time interval, For the detection time interval, This represents the total number of time intervals during the lifting process. ,in, for The lifting tonnage at any given moment, for The tilt angle of the boom at all times. for The lifting speed at any given moment; Extract the lifting tonnage and lifting speed at each detection moment, and calculate the output power of the hoisting mechanism based on the lifting tonnage and lifting speed. ,in, for The output power of the lifting mechanism at all times. Design coefficient, for The lifting tonnage at any given moment, for The lifting speed at any given moment, For mechanical efficiency; The hoisting mechanism's operating status is checked based on its output power. The output power of the hoisting mechanism is compared with a preset output power threshold. If the output power of the hoisting mechanism is greater than or equal to the preset output power threshold, an overload signal awaiting review is output. If the output power of the hoisting mechanism is less than the preset output power threshold, a no-overload signal awaiting review is output.

[0048] In container hoisting operations at port terminals, this invention requires real-time monitoring of the hoisting mechanism's operating status to ensure safe crane operation and prevent overloading or abnormal operation. Assuming a gantry crane is performing container hoisting operations, the system first acquires real-time detection signals from the hoisting mechanism using sensors, constructing a detection signal sequence. The lifting tonnage and lifting speed at each moment are extracted, and the output power of the hoisting mechanism at each moment is calculated using a power calculation formula. Subsequently, the calculated output power is compared with a preset output power threshold. If the power is greater than or equal to the threshold, the system determines that the hoisting mechanism may be at risk of overloading and sends a "pending overload signal" to remind operators to check or adjust the lifting load; if the power is lower than the threshold, a "pending no overload signal" is sent, indicating that the current hoisting status is normal. Through this process, port management personnel can monitor the crane's operating status in real time, ensuring not only the safety of hoisting operations but also providing data support for maintenance plans and equipment lifespan management. For example, when continuously hoisting multiple containers, the system can automatically record the power curve for each hoisting operation, generating historical power data reports to provide a scientific basis for equipment maintenance and load management.

[0049] Preferably, the rated operating current of the lifting frequency converter is obtained based on the detection signal, and the specific steps are as follows: Formula for calculating the output power of the hoisting mechanism and the formula for calculating electrical power. ,in, for Constant electrical power for Operating voltage at all times for Constant operating current; Depend on ,get Therefore, we get That is, under the conditions of rated lifting tonnage and lifting speed, the rated operating current is a fixed value.

[0050] Preferably, the real-time operating current of the hoisting inverter is read through the communication cable between the PLC system and the inverter. Based on the rated operating current and the real-time operating current, the secondary operating status detection of the hoisting mechanism is performed. The specific steps for comparing the rated operating current and the real-time operating current are as follows: When an overload signal awaiting review is output, the rated operating current is compared with the real-time operating current. If the rated operating current is less than the real-time operating current, the hoisting mechanism is in a non-overload state and continues to operate normally; otherwise, the hoisting mechanism is in an overload state and stops operating. When the output shows no overload signal pending review, the rated operating current is compared with the real-time operating current. If the rated operating current is greater than or equal to the real-time operating current, an overload signal is output to determine that the hoisting mechanism is in an overload state, and the hoisting mechanism stops operating. Conversely, if the rated operating current is not greater than or equal to the real-time operating current, the hoisting mechanism is in a non-overload state and continues to operate normally.

[0051] In the lifting operation of a bridge crane at a port terminal, in order to ensure the safe operation of the hoisting mechanism, the monitoring system not only calculates the rated operating current, but also obtains the operating current of the frequency converter in real time through the communication cable between the PLC system and the frequency converter, and performs secondary operation status detection on the hoisting mechanism.

[0052] When the hoisting mechanism outputs an "overload signal pending review" during a single operational status check, the system compares the rated operating current with the real-time operating current. If the rated operating current is less than the real-time operating current (e.g., the rated current is 105A while the real-time current is 110A), the actual load on the hoisting mechanism does not exceed its rated capacity, and the system determines that the hoisting mechanism is not overloaded, allowing it to continue normal operation. Conversely, if the real-time current is lower than the rated current, it indicates an overload risk, and the system will determine that the hoisting mechanism is overloaded, automatically stopping the hoisting operation to prevent equipment damage or safety accidents.

[0053] When a test outputs "No overload signal pending review," the rated operating current is compared with the real-time operating current. If the rated operating current is greater than or equal to the real-time operating current (e.g., rated current 110A, real-time current 100A), but the system still detects an overload risk, it will output an "Overload confirmed" signal, and the hoisting mechanism will stop operating to ensure safety. Conversely, if the real-time current is lower than the rated current and has not reached the danger threshold, the hoisting mechanism is determined not to be overloaded and continues to operate normally.

[0054] Through this secondary operational status detection mechanism, port management personnel can make precise judgments based on the initial mechanical power assessment, combined with real-time electrical data, to achieve dynamic protection of the hoisting mechanism. This not only effectively prevents accidents caused by overload, but also ensures the safety and reliability of crane equipment during high-load or continuous operations, improving operational efficiency and safety management levels.

[0055] A gantry crane torque limiting protection system based on current verification includes a signal acquisition and processing module, a wire rope vibration interference analysis module, a primary operating status detection module, a secondary operating status detection module, and an operating control decision module. The signal acquisition and processing module is connected to the wire rope vibration interference analysis module, which is connected to the primary operating status detection module, which is connected to the secondary operating status detection module, and the secondary operating status detection module is connected to the operating control decision module.

[0056] The signal acquisition and processing module is used to acquire the detection signal output by the torque sensor in real time. It acquires the swing signal in real time by arranging a triaxial accelerometer at the wire rope connection and preprocesses the detection signal and the swing signal. The wire rope vibration interference analysis module is used to track the vibration displacement variable of the wire rope based on the swing signal, analyze the vibration interference factor of the wire rope, and determine the accuracy of the output detection signal by correlating the detection signal. The primary operation status detection module is used to perform a primary operation status detection of the hoisting mechanism based on the detection signal when the accuracy of the detection signal is determined to meet the standard. The secondary operation status detection module is used to obtain the rated operating current of the hoisting frequency converter based on the detection signal, read the real-time operating current of the hoisting frequency converter through the communication cable between the PLC system and the frequency converter, and perform secondary operation status detection of the hoisting mechanism based on the rated operating current and the real-time operating current. The operation control decision module controls the operation of the hoisting mechanism based on the results of the secondary operation status detection.

[0057] like Figure 2 The diagram shown is a system block diagram of a gate operator torque limiting protection system based on current verification according to an embodiment of the present invention, which can be used to perform... Figure 1 The steps in the method embodiments shown are implemented in a similar manner and have similar technical effects, and will not be repeated here.

[0058] Through the above embodiments, this invention acquires real-time detection signals of the hoisting mechanism using a torque sensor and obtains swing signals using a triaxial accelerometer at the wire rope connection. Based on the wire rope jitter displacement analysis, the accuracy of the detection signals is determined by the jitter interference factor. Under the premise of accurate signals, a first-stage mechanical power calculation for operational status detection is performed. Then, a second-stage operational status detection is performed, combining the rated operating current of the hoisting inverter calculated from the detection signals with the real-time operating current collected by the PLC. The hoisting mechanism is controlled based on the detection results. Through multi-dimensional signal fusion and secondary verification, not only is the detection accuracy and overload determination reliability improved, but overload operation of the equipment is also effectively prevented, ensuring crane operation safety and equipment lifespan.

[0059] This invention utilizes multi-dimensional signal fusion from a torque sensor and a triaxial accelerometer to analyze wire rope vibration interference in real time. After confirming signal accuracy, it performs a mechanical power test and a secondary current verification, thereby accurately determining the operating status of the hoisting mechanism. This multi-level detection mechanism effectively reduces reliance on a single tension signal, filtering abnormal signals caused by wire rope vibration, electromagnetic interference, and other factors, avoiding false alarms or missed alarms due to the torque limiter's sole reliance on tension. This invention significantly improves the stability and accuracy of overload protection signals; reduces the risk of unnecessary equipment downtime and ensures the continuity of hoisting operations; enhances crane operating safety and extends equipment lifespan; and provides reliable safety assurance for high-load or complex operating environments, enabling intelligent monitoring and refined management.

[0060] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

[0061] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gate operator torque limiting protection method based on current verification, characterized in that, Includes the following steps: The detection signal output by the torque sensor is obtained in real time, and the swing signal is obtained in real time by arranging a triaxial accelerometer at the wire rope connection. The detection signal and the swing signal are preprocessed. Based on the swing signal, the jitter displacement variable of the wire rope is tracked, the jitter interference factor of the wire rope is analyzed, and the accuracy of the output detection signal is determined by correlating the detection signal. Once the accuracy of the detection signal is determined to meet the standard, a single operational status test of the hoisting mechanism is performed based on the detection signal. The rated operating current of the hoisting frequency converter is obtained based on the detection signal. The real-time operating current of the hoisting frequency converter is read through the communication cable between the PLC system and the frequency converter. Based on the rated operating current and the real-time operating current, the secondary operating status detection of the hoisting mechanism is performed. The operation of the hoisting mechanism is controlled based on the results of secondary operation status detection.

2. The gate operator torque limiting protection method based on current verification according to claim 1, characterized in that, The swing signals include a first swing signal, a second swing signal, and a third swing signal.

3. The gate operator torque limiting protection method based on current verification according to claim 2, characterized in that, The first swing signal of the wire rope during the lifting process is acquired in real time by arranging a triaxial accelerometer at the wire rope connection, and a first swing signal sequence is formed; the second swing signal of the wire rope during a fixed period before lifting is acquired in real time by arranging a triaxial accelerometer at the wire rope connection, and a second swing signal sequence is formed; the third swing signal of the wire rope during the preset normal lifting process is acquired in real time by arranging a triaxial accelerometer at the wire rope connection, and a third swing signal sequence is formed.

4. The gate operator torque limiting protection method based on current verification according to claim 1, characterized in that, Based on the swing signal, the jitter displacement variable of the wire rope is tracked, the jitter interference factor of the wire rope is analyzed, and the accuracy of the output detection signal is determined by correlating the detection signal. The specific steps include: Obtain a first swing signal sequence and a second swing signal sequence, and determine a first interference coefficient based on the correlation matching of the first swing signal and the second swing signal; Obtain the first swing signal sequence and the third swing signal sequence, and determine the second interference coefficient based on the correlation matching of the first swing signal and the third swing signal; The sum of the first interference coefficient and the second interference coefficient is used to output the vibration interference factor of the wire rope. The jitter interference factor is compared with a preset interference threshold. If the jitter interference factor is greater than or equal to the preset interference threshold, the accuracy of the first detection signal is determined to be non-compliant with the standard. If the jitter interference factor is less than the preset interference threshold, the accuracy of the first detection signal is determined to be compliant with the standard.

5. A gate operator torque limiting protection method based on current verification according to claim 4, characterized in that, Obtain the first swing signal sequence and the second swing signal sequence. Based on the correlation matching of the first swing signal and the second swing signal, determine the first interference coefficient. The specific steps are as follows: Extract the first swing signal sequence to plot the spectrum of the first signal, and extract the second swing signal sequence to plot the spectrum of the second signal. Image association matching is performed based on the spectrum of the first signal and the spectrum of the second signal to output the first association value, and the first interference coefficient is obtained based on the first association value.

6. The gate operator torque limiting protection method based on current verification according to claim 4, characterized in that, Obtain the first swing signal sequence and the third swing signal sequence. Based on the correlation matching of the first swing signal and the third swing signal, determine the second interference coefficient. The specific steps are as follows: Extract the first swing signal sequence and plot the spectrum of the first signal, and extract the third swing signal sequence and plot the spectrum of the third signal; Image association matching is performed based on the spectrum of the first signal and the spectrum of the third signal to output the second association value, and the second interference coefficient is obtained based on the second association value.

7. The gate operator torque limiting protection method based on current verification according to claim 1, characterized in that, Once the accuracy of the detection signal is confirmed to meet the standard, a single operational status test of the hoisting mechanism is performed based on the detection signal. The specific steps are as follows: Real-time acquisition of detection signals and construction of detection signal sequences ,in Let be the detection signal at time t. for The detection signal at any moment, The inspection time during the lifting process, For the i-th time interval, For the detection time interval, This represents the total number of time intervals during the lifting process. ,in, for The lifting tonnage at any given moment, for The tilt angle of the boom at all times. for The lifting speed at any given moment; Extract the lifting tonnage and lifting speed at each detection moment, and calculate the output power of the hoisting mechanism based on the lifting tonnage and lifting speed. ,in, for The output power of the lifting mechanism at all times. Design coefficient, for The lifting tonnage at any given moment, for The lifting speed at any given moment, For mechanical efficiency; The hoisting mechanism's operating status is checked based on its output power. The output power of the hoisting mechanism is compared with a preset output power threshold. If the output power of the hoisting mechanism is greater than or equal to the preset output power threshold, an overload signal awaiting review is output; if the output power of the hoisting mechanism is less than the preset output power threshold, a no-overload signal awaiting review is output.

8. The gate operator torque limiting protection method based on current verification according to claim 1, characterized in that, The rated operating current of the lifting frequency converter is obtained based on the detection signal. The specific steps are as follows: Formula for calculating the output power of the hoisting mechanism and the formula for calculating electrical power. ,in, for Constant electrical power for Operating voltage at all times for Constant operating current; Depend on ,get Therefore, we get That is, under the conditions of rated lifting tonnage and lifting speed, the rated operating current is a fixed value.

9. A gate operator torque limiting protection method based on current verification according to claim 1, characterized in that, The real-time operating current of the hoisting inverter is read through the communication cable between the PLC system and the inverter. Based on the rated operating current and the real-time operating current, the secondary operating status detection of the hoisting mechanism is performed. The specific steps for comparing the rated operating current and the real-time operating current are as follows: When an overload signal awaiting review is output, the rated operating current is compared with the real-time operating current. If the rated operating current is less than the real-time operating current, the hoisting mechanism is in a non-overload state and continues to operate normally; otherwise, the hoisting mechanism is in an overload state and stops operating. When the output shows no overload signal pending review, the rated operating current is compared with the real-time operating current. If the rated operating current is greater than or equal to the real-time operating current, an overload signal is output to determine that the hoisting mechanism is in an overload state, and the hoisting mechanism stops operating. Conversely, if the rated operating current is not greater than or equal to the real-time operating current, the hoisting mechanism is in a non-overload state and continues to operate normally.

10. A gantry crane torque limiting protection system based on current verification, applied to the gantry crane torque limiting protection method based on current verification as described in any one of claims 1-9, characterized in that, The system includes a signal acquisition and processing module, a wire rope vibration interference analysis module, a primary operation status detection module, a secondary operation status detection module, and an operation control decision module; The signal acquisition and processing module is used to acquire the detection signal output by the torque sensor in real time. It acquires the swing signal in real time by arranging a triaxial accelerometer at the wire rope connection and preprocesses the detection signal and the swing signal. The wire rope vibration interference analysis module is used to track the vibration displacement variable of the wire rope based on the swing signal, analyze the vibration interference factor of the wire rope, and determine the accuracy of the output detection signal by correlating the detection signal. The primary operation status detection module is used to perform a primary operation status detection of the hoisting mechanism based on the detection signal when the accuracy of the detection signal is determined to meet the standard. The secondary operation status detection module is used to obtain the rated operating current of the hoisting frequency converter based on the detection signal, read the real-time operating current of the hoisting frequency converter through the communication cable between the PLC system and the frequency converter, and perform secondary operation status detection of the hoisting mechanism based on the rated operating current and the real-time operating current. The operation control decision module controls the operation of the hoisting mechanism based on the results of the secondary operation status detection.

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