Balanced axle synchronous fixed hoist type ship lock traffic bridge lifting system and method

Abstract

This invention discloses a fixed winch-type ship lock traffic bridge lifting system and method based on balance shaft synchronization, belonging to the field of multi-drive point control system technology. The system includes the following steps: displacement sensors and load sensors are respectively installed at at least two drive adjustment lifting points; real-time height and load data of each lifting point are obtained; the deviation of each lifting point relative to a target reference value or system average value is calculated, including height deviation and load deviation; when any deviation exceeds a set threshold, the PLC controller calculates a speed compensation amount based on the current control gain parameters and outputs the speed compensation amount to the drive execution unit through the motion control module. This invention effectively alleviates stress concentration problems and significantly improves structural safety and service life.

Description

Technical Field

[0001] This invention relates to the technical field of multi-drive point control systems, specifically to a fixed winch-type ship lock traffic bridge lifting system and method based on balance shaft synchronization. Background Technology

[0002] The current lifting system of the lock traffic bridge mainly faces the following challenges: In terms of synchronization accuracy, the traditional hydraulic synchronization method is significantly affected by changes in ambient temperature and pipeline resistance, which often results in inconsistent lifting heights of multiple drive lifting points during the simultaneous lifting process, thus generating large displacement errors, causing uneven stress and stress concentration in the bridge body, and affecting structural safety. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a fixed winch-type lock traffic bridge lifting system and method based on balance shaft synchronization.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] This invention provides a method for lifting a fixed winch-type ship lock traffic bridge based on balance shaft synchronization, comprising the following steps:

[0006] Displacement sensors and load sensors are installed at at least two drive adjustment lifting points. The displacement sensors are used to detect the actual vertical movement height of the lifting points, and the load sensors are used to detect the real-time load value borne by the lifting points. Both the displacement sensors and the load sensors are connected to the PLC controller through an industrial fieldbus interface.

[0007] Data is collected from displacement sensors and load sensors at all lifting points at a fixed sampling period to obtain real-time height and load data for each lifting point.

[0008] A system deviation model is constructed based on real-time sampling data to calculate the deviation of each lifting point relative to the target reference value or the system average value. The deviation includes height deviation and load deviation.

[0009] When any deviation exceeds the set threshold, the PLC controller calculates the speed compensation amount based on the current control gain parameter and outputs the speed compensation amount to the drive execution unit through the motion control module.

[0010] The present invention also provides a fixed winch-type lock traffic bridge lifting system, the system comprising:

[0011] The central drive frame contains a dual-output shaft reducer, with both ends of its output shaft connected to a rigid transmission shaft via gear couplings.

[0012] The drive shaft runs laterally through the winch frames on both sides of the bridge body and is connected to the respective drum devices through drum couplings to achieve rigid power transmission.

[0013] Each drum device leads out several steel wire ropes, which are guided by fixed pulleys to each automatic pulley structure. The end of the lifting point is connected to the balance wheel mechanism. By setting two sets of central drive frames and winch frames arranged side by side, a symmetrical four-point suspension closed loop system is formed.

[0014] A load sensor is installed at the shaft center of the balance wheel mechanism, and a displacement sensor is installed at the end of the drum, for real-time monitoring of height and load information during the lifting process.

[0015] The PLC controller collects and analyzes height and load data. When any lifting point deviates, the variable frequency speed control compensation command is calculated based on the deviation to achieve synchronous lifting control of the four points of the bridge.

[0016] The beneficial effects of this invention are:

[0017] In this invention, the height and load of multiple lifting points are obtained at a fixed sampling period, and the deviation of the relative average value is calculated in real time. When any deviation exceeds the limit, an error feedback speed command compensation mechanism based on PLC calculation is activated, which can effectively eliminate the maximum displacement error between lifting points. This method is particularly suitable for long-span structures with multiple supports, such as lock bridges. Compared with the traditional hydraulic synchronization method (which is easily affected by oil temperature and has large synchronization errors), this method can compress the synchronization deviation to the millimeter level, effectively alleviate the stress concentration problem, and significantly improve the structural safety and service life. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0019] Figure 1 This is a schematic diagram illustrating the workflow of the fixed winch-type ship lock traffic bridge lifting method based on balance shaft synchronization according to the present invention.

[0020] Figure 2 This is a schematic diagram of the structure of the fixed winch-type lock traffic bridge lifting system of the present invention.

[0021] Figure 3 This is a schematic diagram of another structure of the fixed winch-type lock traffic bridge lifting system of the present invention.

[0022] In the diagram: 1. Central drive frame; 2. Reducer; 3. Coupling; 4. Drive shaft; 5. Winch frame; 6. Drum assembly; 7. Wire rope; 8. Pulley structure; 9. Balance wheel mechanism. Detailed Implementation

[0023] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0024] Example 1

[0025] like Figure 1 As shown, the method for lifting a fixed winch-type lock traffic bridge based on balance shaft synchronization includes the following steps:

[0026] Displacement sensors and load sensors are installed at at least two drive adjustment lifting points. The displacement sensors are used to detect the actual vertical movement height of the lifting points, and the load sensors are used to detect the real-time load value borne by the lifting points. Both the displacement sensors and the load sensors are connected to the PLC controller through an industrial fieldbus interface.

[0027] In this embodiment, the number of lifting points is set to four. Specifically, a dual-output shaft reducer is installed inside the central drive frame. The two ends of its output shaft are connected to rigid transmission shafts. The transmission shafts pass through the left and right winch frames laterally along the bridge body and are connected to their respective drum devices through drum couplings to achieve rigid power transmission. Each drum device leads out several steel wire ropes, which are guided to each automatic pulley structure through fixed pulleys. The end of the lifting point is connected to the balance wheel mechanism. Two sets of central drive frames and winch frames are arranged side by side, that is, four sets of lifting points, thus forming a symmetrical four-point suspension closed-loop system.

[0028] The following sensors are installed at each suspension point:

[0029] Displacement sensor: Employs an absolute encoder or laser rangefinder to detect vertical movement height in real time;

[0030] Load cells: Piezoelectric or strain gauge sensors are used to monitor the load in real time;

[0031] The aforementioned sensor signals are connected to the PLC system via industrial fieldbus interfaces (such as PROFINET, CANopen, EtherCAT, etc.) to ensure the real-time performance and reliability of data transmission. At the same time, it is also necessary to ensure that the system has the ability to perform high-frequency parallel sampling of multiple suspension points.

[0032] Data is collected from displacement sensors and load sensors at all lifting points at a fixed sampling period to obtain real-time height and load data for each lifting point.

[0033] By setting a fixed sampling period (e.g., 10ms~50ms), the PLC will periodically collect the real-time height and load height of each lifting point. This sampling mechanism ensures that the system can obtain accurate multi-point status information under the premise of high-speed dynamic response, providing basic data for subsequent control.

[0034] A system deviation model is constructed based on real-time sampling data to calculate the deviation of each lifting point relative to the target reference value or the system average value. The deviation includes the height deviation ΔH. i (t) and load deviation ΔF i (t);

[0035] The core significance of this step lies in achieving a quantitative assessment of the current platform status and forming an error feedback control quantity, and preferably calculating the deviation of each lifting point relative to the average value of multiple lifting points.

[0036] When any deviation exceeds the set threshold, the PLC controller calculates the speed compensation amount based on the current control gain parameter, and outputs the speed compensation amount to the drive execution unit through the motion control module. The instruction is output to the driver through the motion control module (such as the motion control function built into the PLC or an external servo control unit) to achieve precise fine adjustment of the lifting point speed.

[0037] The motion control module consists of a rigid main control channel and a flexible auxiliary adjustment channel. The main control channel is used to ensure the overall structural support balance and is responsible for coarse synchronization and platform stability. The auxiliary adjustment channel performs independent speed adjustment for each suspension point based on error feedback to eliminate inconsistencies caused by dynamic disturbances. This "rigid guarantee + flexible calibration" mode can significantly improve the robustness of the system.

[0038] The PLC controller integrates an anomaly detection module. When an anomaly is detected, it enters a preset safety control mode and prevents equipment damage or system instability through drive limitation or emergency stop mechanisms.

[0039] Considering the high requirements for stability and safety in industrial control systems, the PLC is embedded with a multi-dimensional anomaly detection module, which has the following capabilities: sensor data mutation detection (such as instantaneous jumps, distortion drift), communication interruption diagnosis (such as bus disconnection, response timeout), control chain closed loop disconnection identification (such as drive non-response, running overtravel), emergency stop input monitoring and status locking mechanism.

[0040] Once an anomaly is detected, the system will enter a safety control mode and automatically activate the following protective actions: speed limiting control or speed zeroing, triggering a "slow stop" or "mechanical lock" command for the driver, and sending alarm information to the host system or remote terminal.

[0041] In addition to being applicable to the lifting system of the lock traffic bridge, the method of the present invention is also applicable to other lifting systems, such as the construction platform for replacing the expansion joint of urban bridges and the leveling platform of the high-precision heavy-duty assembly platform.

[0042] Furthermore, the core of the systematic deviation model is to use the average value of all lifting points as a dynamic reference benchmark, and calculate the height deviation and load deviation of each lifting point separately. The construction process of the systematic deviation model is as follows:

[0043] First, the average height of all n suspension points is shown below:

[0044] ;

[0045] Choosing the mean as a benchmark allows for real-time, dynamic, and symmetrical adjustments, making it suitable for scenarios with non-uniform loads or inconsistent lifting. The average value reflects the system's "target state" or "desired state," making it suitable for multi-point coordinated adjustment. Compared to a fixed target value, it can better adapt to complex scenarios such as bridge body flexible response and self-weight offset.

[0046] The height deviation ΔH i (t) represents the measured height H of the i-th drive point at time t. i The absolute difference between (t) and the mean height of all n suspension points is expressed as follows:

[0047] ;

[0048] Absolute value processing ensures that the deviation definition is not affected by positive or negative direction, making it suitable for downstream control threshold determination. It guarantees that the system makes judgments based on the maximum deviation, which complies with safety design principles.

[0049] The average load sampled from all n lifting points is shown below:

[0050] ;

[0051] The load deviation ΔF i (t) represents the real-time load value F at the lifting point. i The absolute difference between (t) and the mean of the sampled loads at all n lifting points is expressed as follows:

[0052] .

[0053] Among them, by measuring the height deviation ΔH of the lifting point i (t) and load deviation ΔF iThe precise definition of (t) is based on the fact that each suspension point is compared with the overall average state, rather than just referring to the target value. A unified system deviation model is constructed to provide a mathematical basis for subsequent dynamic compensation control. It is applicable to flexible structures with multiple suspension points. Through this definition mechanism, dynamic deviation quantification can be performed, thereby supporting error-driven feedback control.

[0054] The system deviation model calculates the deviation between each suspension point and the system average state in real time, enabling dynamic monitoring of the bridge's attitude and stress, and providing input for subsequent speed compensation.

[0055] Furthermore, the control gain parameter includes the height error control gain coefficient K. p With load error control gain coefficient K f The height error control gain coefficient and the load error control gain coefficient support dynamic adaptive adjustment. The initial values ​​are obtained through offline identification based on the platform structure response characteristics and stored in the PLC parameter configuration area.

[0056] The core of adaptive gain adjustment is to dynamically adjust the control gain based on real-time feedback data from the system. In this embodiment, the system monitors the height deviation ΔH of each lifting point in real time. i (t) and load deviation ΔF i (t), and adjust the control gain coefficient K according to the rate of change of these deviations. p and K f This adjustment mechanism is designed to take into full account factors such as load changes, environmental influences, and mechanical wear under different working conditions, ensuring that the system can be flexibly adjusted as needed in practical applications to achieve the best synchronous control effect.

[0057] During operation, the PLC controller continuously records the height deviation ΔH. i (t) and load deviation ΔF i (t) The trend change within consecutive sampling periods, and the following recursive adjustment operation is performed every N periods:

[0058] ;

[0059] ;

[0060] Among them, K p (t) represents the height error control gain coefficient at the current time t, and is related to the height deviation ΔH. i The rate of change of (t) is related to K. When high synchronization accuracy is required, K... p Sufficient response speed is required to quickly adjust when a large deviation is detected, K pThe initial range is usually set to [0.5, 2.0]. The upper limit is used when the synchronization accuracy requirement is high, and the lower limit is used when the system inertia is large.

[0061] K f (t) represents the load error control gain coefficient at the current time t, and is related to the load deviation ΔF. i The rate of change of (t) is related to K. f The value of K will be flexibly adjusted according to changes in load to ensure that the system can cope with different load conditions and maintain stable operation. f The initial range is usually [0.1, 1.0]. In scenarios with frequent load fluctuations, the gain should be increased to enhance the response.

[0062] K p (t+Δt) represents the height error control gain coefficient at the next update, K f (t+Δt) represents the load error control gain coefficient at the next update. This represents the rate of change of the height deviation of suspension point i with respect to time. This represents the rate of change of the load deviation at lifting point i with respect to time. If the trend of the rate of change is "error increasing," the gain coefficient automatically increases to improve the response speed. If the error tends to converge, the gain coefficient automatically decreases to prevent overcompensation or oscillation. For example, if... If K > 0 and increases, it indicates that the synchronization error is increasing, and the system automatically increases K. p To quickly correct the deviation, similarly, when the load changes drastically, increase K. f It can adjust traction compensation more quickly.

[0063] γ1 represents the height error adjustment slope coefficient, used to control the sensitivity of height error gain adjustment, and γ2 represents the load error adjustment slope coefficient, used to control the sensitivity of load error gain adjustment. In the formula, γ1 and γ2 represent the sensitivity of the adjustment process. When the value of γ1 is larger, the system is more sensitive to changes in height error and can adjust the height synchronization state more quickly, but it may cause system oscillation. When the value of γ1 is smaller, the system response is more stable, but the adjustment speed is slower. Similarly, when the value of γ2 is larger, the system is more sensitive to load changes and is suitable for working conditions with frequent load fluctuations, while when the value of γ2 is smaller, it is suitable for working conditions with relatively stable loads.

[0064] Preferably, γ1∈[0.02,0.2]: the system response speed and oscillation risk need to be balanced; γ2∈[0.01,0.1]: since the load error changes slowly, the sensitivity should be moderate; γ1 and γ2 can be calibrated by step response test, observe the system's settling time and overshoot under different rates of change, and optimize to find that when the system response is fast, the coefficient should be small to avoid overshoot; when the response is slow, the coefficient needs to be amplified to enhance the feedback adjustment rate.

[0065] For example, in heavy-load conditions: high lifting force is required, K f Automatically too large;

[0066] When the elevation difference error increases: the system enhances the synchronization response and automatically increases K. p ;

[0067] When the temperature rises or wear is severe: due to the slow mechanical response, γ1 can be appropriately increased to compensate for the delay.

[0068] In this embodiment, K p The initial value is 0.8 (after curve fitting of 200 bridge test runs, ΔH) i The stable response interval is located in [0.7, 0.9], K f The initial value of γ1 is 0.3 (the structure is rigid and the load has a weight less than the height), the initial value of γ2 is 0.025, and the initial value of γ3 is 0.02.

[0069] These coefficients are set based on the dynamic characteristics and response speed requirements of the system. By tracking the rate of change of deviation in real time, it can be ensured that the control gain is adjusted in a timely manner under different load changes and motion states, avoiding system instability caused by over-adjustment or lag adjustment.

[0070] The process of gain adjustment:

[0071] Real-time data acquisition: The system collects the height deviation and load deviation of each lifting point, and calculates the rate of change of deviation of each lifting point by combining the real-time processing capability of the PLC controller.

[0072] Calculate the gain adjustment amount: Based on the rate of change of the deviation, the gain is adjusted using a formula. In the formula, γ1 and γ2 represent the sensitivity of the adjustment process, which can be optimized according to the system requirements and characteristics.

[0073] Output adjustment command: The PLC controller outputs speed compensation command to the drive execution unit in real time according to the adjusted gain value, thereby adjusting the lifting speed of each lifting point and ensuring the synchronization of the entire bridge.

[0074] The gain adaptive adjustment mechanism of this invention is designed to effectively solve the synchronization errors and load variation problems that may occur in the actual operation of a four-point synchronous lifting system. Since the working environment and load of each lifting point dynamically change over time, traditional fixed-gain control methods cannot ensure optimal synchronization accuracy and stability under various operating conditions. The introduction of the gain adaptive adjustment mechanism can adjust the control gain in real time based on system feedback data, thereby optimizing the response speed and stability of the entire synchronous lifting system.

[0075] In practical applications of this invention, the gain adaptive adjustment mechanism can cope with various working condition changes. For example, when the bridge lifting system is under heavy load, the load deviation may be large. The system can adjust the gain by increasing K. f To accelerate the response to load changes; when the bridge is subjected to temperature changes or mechanical wear during lifting, the height deviation may be large, and the system will increase K to accelerate the response to load changes; p To enhance the accuracy of height adjustment.

[0076] Furthermore, the PLC controller adopts a parallel mechanism of main cycle and auxiliary cycle;

[0077] The main cycle is used to execute the main loop of the control algorithm, including deviation calculation, speed command generation, and data archiving;

[0078] The main cycle is the core execution flow of system control, and its cycle is generally set to T. m =100ms, specific functions include:

[0079] The core control algorithm calculation involves calculating the height deviation ΔH. i (t) and load deviation ΔF i (t) is used for dynamic calculation;

[0080] Speed ​​command generation: Generate inverter speed compensation command V based on the joint compensation strategy. adj ;

[0081] Historical data archiving and trend modeling: used for subsequent adaptive updates of gain coefficients;

[0082] Main control link coordination output: to complete the scheduling of drive control tasks under a unified time rhythm.

[0083] The auxiliary cycle is used to perform the following real-time self-test tasks: detection of sudden data changes in displacement sensor and load sensor, monitoring of bus communication status, diagnosis of driver operating status, and listening to and responding to emergency stop signals.

[0084] The auxiliary cycle is a fast, lightweight control self-checking mechanism, and its cycle is usually set to T. s =10ms, high frequency ensures the system quickly captures abnormal states. Main functions are as follows:

[0085] Real-time sensor mutation detection: including identification of mutation amplitude in displacement and load sample values;

[0086] Communication link integrity detection: monitoring of bus signal status and frame rate stability;

[0087] Execution unit status prediction: Check the working status of execution units such as frequency converters and encoders;

[0088] Emergency stop logic monitoring: High-priority interrupt response strategies ensure that the system can quickly switch to safe mode;

[0089] Feedback filtering and redundancy activation: Dynamically switch redundant channels.

[0090] Traditional PLCs have a single cycle design and lack high-frequency status detection capabilities, resulting in delayed response to sudden risks (such as sensor distortion and cable breakage). This cannot meet the requirements for structural safety and control stability in bridge lifting scenarios. Furthermore, the single-cycle main program cannot take into account both compensation instructions and system monitoring needs, leading to task scheduling conflicts. This is especially true in situations where the synchronous lifting structure in the middle of the bridge is complex and real-time detection needs are intensive, which can easily cause problems such as system overload and missed detections.

[0091] Therefore, this invention proposes a PLC control architecture based on a master-slave dual-cycle parallel task mechanism, aiming to achieve coordination and improvement in control accuracy, system stability, and real-time response.

[0092] The "master-slave cycle asynchronous parallel architecture" proposed in this invention achieves the following effects:

[0093] Improved real-time response: High-frequency 10ms auxiliary cycle ensures that abnormal states are captured immediately;

[0094] Ensure stable operation of the main control task: The main cycle control calculation is not interrupted by the state detection task, thus improving the determinism of the calculation;

[0095] Enhanced safety and redundancy response capabilities: Abnormal state trigger signals can be processed for emergency system stop through the auxiliary cycle interrupt mechanism, providing extremely high fault tolerance;

[0096] Adaptable to complex lock and bridge application scenarios: Facing environments with long-term operation, multi-point control, and severe dynamic structural offset, this mechanism has strong adaptability and deployment flexibility.

[0097] The specific working steps of the algorithm in the system of this invention are as follows:

[0098] per T s =10ms cycle, read raw data from absolute encoder and load sensor through auxiliary task;

[0099] Passed into the main task (per T) m =100ms), complete: calculation of average height and average load, height deviation ΔH i (t) and load deviation ΔF i (t) Calculation;

[0100] Determine if the threshold is exceeded before proceeding with further steps.

[0101] Furthermore, the threshold includes the maximum allowable threshold ε for height deviation.H and the maximum allowable threshold ε for load deviation F ;

[0102] When the height deviation ΔH i >ε H And the load deviation ΔF i ≤ε F When the vertical height is abnormal at a certain point, the system performs independent compensation based on the height deviation. This indicates that there is an abnormal vertical height at that point, but the load does not fluctuate significantly. This may be due to wear of the mechanism or a local jam. At this time, the system performs individual compensation based on the height deviation to adjust the speed of the winch so that it gradually returns to the average height.

[0103] When the load deviation ΔF i >ε F And the height deviation ΔH i ≤ε H When independent compensation based on load deviation is performed, it indicates that although the lifting height is consistent, there is structural stress concentration due to abnormal force on the lifting point. At this time, an independent compensation strategy based on load deviation is adopted to relieve stress by changing the movement trend of the lifting point to unload / load it.

[0104] When the height deviation ΔH i With load deviation ΔF i When both exceed the threshold, it indicates that there is a significant abnormality in the position and force of the suspension point, and joint compensation is performed:

[0105] ;

[0106] Among them, V adji This represents the speed compensation required for the i-th suspension point. This expression couples height and load into a linearly combined speed command, enabling synchronous dynamic adjustment of attitude and load.

[0107] Based on structural stiffness analysis and measured data, 10 mm is close to the critical deformation limit of the structure. Therefore, ε in this invention... H The deviation can be 10mm. When the deviation is greater than 10mm, the structure shows a detectable attitude deviation and needs to be adjusted.

[0108] Preferably, the maximum allowable threshold for load deviation is 5%Q, where Q is the rated load of the lifting point design. For example, if Q = 100kN, then the deviation threshold is 5kN.

[0109] Application scenario example:

[0110] During the lifting operation of the lock traffic bridge, it is common for a certain lifting point to rise / fall first due to uneven distribution of the bridge deck structure's self-weight or the influence of wind load. If dynamic correction is not carried out at this time, the bridge deck will tilt or "tilt," which will induce structural fatigue or even breakage of the wire rope.

[0111] Control process:

[0112] The bridge lifting operation began, with the initial heights of the four lifting points approximately the same.

[0113] A certain lifting point shifts due to a difference in wire rope preload; the system calculates ΔH. i =16mm, ΔF i =6.1%Q;

[0114] The PLC determines that the threshold is exceeded and enters compensation mode.

[0115] Calculate V adj Start the winch at the offset lifting point and fine-tune its speed;

[0116] After about 200ms, all suspension points regained synchronization, and the error dropped back to less than 5mm.

[0117] This process can be executed cyclically, with each cycle being closed to ensure dynamic balance during the improvement process.

[0118] Furthermore, the displacement sensor is an absolute encoder with power-off memory function, which records the last height value before the power failure after an abnormal power failure.

[0119] The absolute encoder used in this invention differs from ordinary incremental encoders and possesses the following core characteristics:

[0120] Power-off memory: Built-in EEPROM memory can permanently retain the last encoded data after power failure;

[0121] High resolution: To meet the requirements of synchronous enhancement, a 16-bit SSI interface is selected;

[0122] Interface compatibility: Supports standard industrial bus protocols (such as PROFINET or SSI) for PLCs (such as Siemens S7-1500) to ensure real-time performance and anti-interference capabilities;

[0123] Environmental adaptability: With an IP67 protection rating, it is suitable for typical lock operating environments such as humidity, heat, oil, and high dust. These characteristics make it the preferred solution for maintaining the continuity of synchronous control in the event of a power outage.

[0124] When the PLC controller is powered on again, it reads all coded values ​​and adjusts the zero offset uniformly through a reference height calibration algorithm.

[0125] To ensure that the system can maintain the flatness and four-point symmetry of the bridge deck after power failure, the following height reference calibration algorithm is designed in the PLC:

[0126] First, record the last pre-power-on encoded value as H for each suspension point i. iold This refers to the actual height sampled last time before the power outage; after power is restored, the EEPROM stored value in the current encoder is read. It provides data on the retention of the actual mechanical displacement during power outages;

[0127] The difference between the two is:

[0128] ;

[0129] Where, ΔH i zero The zero offset of the current lifting point i represents the height reference drift caused by power failure, ranging from ±2 to 10 mm.

[0130] The marriage calibration logic is as follows:

[0131] First, optionally, a global reference baseline is established with the left anterior suspension point (denoted as i=1) as a reference:

[0132] ;

[0133] in, This is represented as the offset reference for the global reference lifting point;

[0134] For all suspension points i, adjust uniformly as follows:

[0135] ;

[0136] Among them, H i new This new height after calibration, i.e., the calculated corrected height value, is used as the starting reference for the next step of control.

[0137] The entire system is designed to ensure that "synchronous control can be quickly restored even in the event of a sudden power outage." The following is a step-by-step procedure in actual operation:

[0138] Sudden power outage occurred:

[0139] When the lifting point stops operating and the control PLC loses power, the absolute encoder immediately writes the current position into the EEPROM (non-volatile memory), and the PLC's RAM buffer stores the last height value (H). i old Automatic power-off retention.

[0140] The system restarts after power cycling:

[0141] The PLC performs a power-on self-test, initiates bus communication with the four drive points, and reads the position stored in the EEPROM of each encoder before the power failure. Simultaneously extract H from the PLC buffer. i old ;

[0142] Calculate the zero offset:

[0143] Calculate the zero offset ΔH for each suspension point i. i zero This step reveals whether the bridge structure actually shifted during the power outage and whether the various suspension points remained synchronized.

[0144] Reference point calibration:

[0145] Establish a global reference datum and uniformly correct all suspension points to the new height H after the offset datum is calibrated. i new This step is equivalent to "eliminating global bias and maintaining relative consistency";

[0146] System restart preparation:

[0147] H i new The synchronous control module written to the PLC compares the position with the original target position and calculates ΔH. i Start the fine compensation controller and calculate V adj Used for soft start and resynchronization processes;

[0148] The system has begun the upgrade process:

[0149] All lifting points are lifted synchronously based on the new starting height, and the system dynamically corrects deviations in real time to achieve millimeter-level control accuracy.

[0150] Furthermore, the height change rate dH of the i-th suspension point is calculated within each sampling period. i / dt and the load change rate dF of the i-th lifting point i / dt, if the rate of change of height dH i / dt exceeds the maximum allowed threshold β H or load change rate dF i / dt exceeds the maximum allowed threshold β F Enter amplitude limiting compensation mode and limit the output speed before output:

[0151] The maximum rate of change is determined by the speed limit proportional coefficient α. max Restrictions are imposed, and outliers are timestamped for subsequent diagnosis.

[0152] In the synchronous lifting system of the lock traffic bridge solved by the present invention, the bridge structure is huge (span of 9.5m) and the load is uneven. The four lifting points must maintain high-precision synchronization to prevent stress concentration. However, even if a rigid drive shaft is introduced to achieve preliminary synchronization, it is impossible to completely avoid dynamic deviations caused by sudden load changes, local slippage or sensor noise.

[0153] In particular, the following two operating conditions can easily lead to system instability or mechanical damage:

[0154] The rate of change of altitude is too fast (dH) i / dt): This may cause a point in the bridge structure to rise or fall rapidly, inducing local structural fatigue;

[0155] The load change rate is too fast (dF) i / dt): This may be due to sudden slippage of the drum, local instability of the wire rope, or redistribution of force at the suspension point.

[0156] Traditional control methods mainly focus on the magnitude of the "deviation" itself, but lack effective constraints on the "rate of change" of the deviation, making it difficult to achieve compatibility between high-speed response and control stability. Therefore, this invention sets up a "rate of change limiting compensation mechanism" as a dynamic protection logic patch module in PLC control.

[0157] Among them, the maximum allowable threshold β for the rate of change of height H The preferred value is 5 mm / s (derived by inversely from the measured encoder sampling rate (100 Hz) and the maximum drum drive speed (50 mm / s), with the limit set at 10% of that). The maximum allowable threshold for the load change rate is β. F The preferred value is 2%Q / s (derived based on the fact that the maximum allowable dynamic load fluctuation of the structure does not exceed ±5% of the rated load), and the speed limiting proportional coefficient α max The preferred value is 0.6~0.8 to ensure a balance between response performance and safety stability. max When the value is 0.7, the system has the shortest average settling time and the lowest oscillation.

[0158] When the theoretical compensation speed before the gear shift is V adj Then when the rate of change of height dH i / dt and the rate of change of load dF i If / dt does not exceed the threshold, the output speed will remain V. adj When the rate of change of height dH i / dt exceeds the maximum permissible threshold β for a high rate of change. H Or the load change rate exceeds the maximum allowable threshold β for load change rate. F At that time, control the output speed V cmd for:

[0159] ;

[0160] Here, sgn(·) is the sign function, which determines the amplitude limiting direction.

[0161] Furthermore, each of the drive adjustment lifting points is equipped with two sets of displacement sensors and load sensors, and each set of sensors is connected to the PLC controller through an independent channel;

[0162] During the sampling period, data from two sets of displacement sensors and load sensors are simultaneously acquired. A consistency comparison is performed by the PLC controller, and the deviation value δ is calculated. sync If the deviation value δ sync Exceeding the set value δ max Then perform the following steps:

[0163] The current lifting point compensation is set to zero;

[0164] Channel marker expired, switch to backup;

[0165] Automatic recalibration will be performed in the next cycle.

[0166] Stable operation and accurate data acquisition of precision sensors are the key foundation for achieving closed-loop synchronous control. Sensor failure will directly lead to inaccurate error feedback, which in turn will cause structural imbalance and induce safety accidents. Therefore, this invention sets up two sets of displacement sensors and load sensors at each drive lifting point.

[0167] The load cell is preferably a bridge-type load cell, with an accuracy preferably of 0.5%FS. The comparison tolerance is assumed to be four times this value, i.e., δ. max =2.0%Q;

[0168] The displacement sensor has an accuracy of 0.1 mm, and its threshold range δ can be set. max It is ±3mm.

[0169] In a typical synchronous lifting application for a 9.5m span traffic bridge:

[0170] Four lifting points are respectively arranged at both ends of the bridge. Each lifting point is equipped with two sets of sensors (8 sampling sensors). The PLC compares redundant data at a 10ms cycle to achieve 100 synchronous checks per second. If a channel failure is detected, the system completes channel switching and zeroing of deviation within 10ms. The deviation is remodeled in the next cycle to avoid unnecessary compensation commands triggered by erroneous data, thus ensuring symmetrical force on the bridge and smooth lifting.

[0171] Example 2

[0172] refer to Figures 2-3 The present invention also provides a fixed winch-type lock traffic bridge lifting system, the system comprising:

[0173] The central drive frame 1 is equipped with a dual-output shaft reducer 2, and the two ends of its output shaft are connected to rigid transmission shafts 4 through gear couplings 3 respectively.

[0174] The drive shaft 4 runs laterally through the winch frames 5 on both sides of the bridge body and is connected to the respective drum devices 6 through the drum coupling 3 to achieve rigid power transmission.

[0175] Each drum device 6 leads out several steel wire ropes 7, which are guided by fixed pulleys to each automatic pulley structure 8. The end of the lifting point is connected to the balance wheel mechanism 9. By setting two sets of central drive frame 1 and winch frame 5 arranged side by side, a symmetrical four-point suspension closed loop system is formed.

[0176] A load sensor is installed at the shaft of the balance wheel mechanism 9, and a displacement sensor is installed at the end of the drum, for real-time monitoring of height and load information during the lifting process.

[0177] The PLC controller collects and analyzes height and load data. When any lifting point deviates, the variable frequency speed control compensation command is calculated based on the deviation to achieve synchronous lifting control of the four points of the bridge.

[0178] The transmission shaft 4 is made of 42CrMo forged steel with a tempered hardness of HB240-280. The gear coupling 3 is preferably a CLZ12 type gear coupling 3.

[0179] The drum device 6 is made of Q355B steel plate with a diameter of δ=26mm and the end shaft is made of 45 steel. It forms a full penetration weld by CO2 gas shielded welding. The compressive strength σy=91.3MPa is verified by ultrasonic testing, and the safety factor reaches 2.59.

[0180] The balance wheel mechanism has a built-in load sensor (accuracy 0.5%FS) on the lifting shaft to monitor the load at the four lifting points (F1-F4) in real time. The drum shaft end is equipped with an SSI interface absolute encoder (displacement sensor) with a sampling period of 10ms and a resolution of 0.01mm, which is used to collect the height of each lifting point (H1-H4).

[0181] Through the rigid transmission chain of dual-output reducer 2-drive shaft 4-drum coupling 3, the mechanical synchronization accuracy reaches 99.2%, eliminating the synchronization error of >50mm caused by oil temperature changes and pipeline pressure drop in the hydraulic system;

[0182] In addition, a three-frame coaxial transmission structure with a single motor driving two winches can be adopted, with a total height of only 3.2m (traditional hydraulic solutions require ≥5m), which is suitable for harsh working conditions with a navigation clearance of <15m. Alternatively, a dual-motor system can be used, with each motor driving a corresponding winch. Figure 3 It is a dual-motor structure, the specific structure of which will not be described in detail.

[0183] Furthermore, from the perspective of system reliability, hydraulic systems have a high risk of leakage during long-term operation, and the commonly used wire rope hoisting mechanism has insufficient safety margin, making it difficult to meet the long-term, high-reliability operation requirements of critical infrastructure.

[0184] To this end, the system is also equipped with a visual monitoring unit, which is used to acquire video images of the wire rope 7 and then identify the broken wire condition of the wire rope 7. Preferably, when the visual monitoring unit (industrial camera) detects a broken wire rate of >5% in real time, an alarm is triggered and the system stops. The visual monitoring unit's identification of the broken wire condition of the wire rope 7 is a prior art, and its structure and working principle will not be described in detail.

[0185] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 fixed hoist type ship lock traffic bridge lifting method based on balanced axle synchronization, characterized in that, The method comprises the following steps: Displacement sensors and load sensors are arranged at at least two driving adjustment lifting points respectively, the displacement sensors are used to detect the actual movement height of the lifting points in the vertical direction, and the load sensors are used to detect the real-time load value borne by the lifting points, and the displacement sensors and the load sensors are connected with a PLC controller through an industrial field bus interface; Data of the displacement sensors and the load sensors of all the lifting points are collected at a fixed sampling period to obtain real-time height and load data of each lifting point; A system deviation model is constructed based on the real-time sampling data, and a deviation amount of each lifting point relative to a target reference value or a system average value is calculated, the deviation amount including a height deviation and a load deviation; When any deviation amount exceeds a set threshold value, the PLC controller calculates a speed compensation amount based on a current control gain parameter, and outputs the speed compensation amount to a driving execution unit through a motion control module; The control gain parameters include a height error control gain coefficient K p and a load error control gain coefficient K f The height error control gain coefficient K p and the load error control gain coefficient K f Support dynamic self-adaptive adjustment, the initial value is obtained by offline identification based on the platform structure response characteristics, and is saved in the PLC parameter configuration area; The threshold value includes a maximum threshold value ε of height deviation allowance H and a maximum threshold value ε of load deviation allowance F ; when the height deviation AH i > ε H and the load deviation AF i ≤ ε F an independent compensation based on the height deviation is performed; When the load deviation ΔF i > ε F and the height deviation ΔH i ≤ ε H , the independent compensation based on the load deviation is performed; When the height deviation AH i When the load deviation AF i When both the height deviation AH and the load deviation AF exceed the threshold values, joint compensation is performed: ； where V adji represents the velocity compensation amount required for the i-th hoist point.

2. The equilibrium axis synchronization based fixed hoist type ship lock transit bridge lifting method according to claim 1, characterized in that, The average of the sampling heights of all n lifting points is as follows: ； the height deviation AH i (t) is the measured height H of the i-th driving lifting point at the t-th time i (t) is the absolute difference value between the i-th driving lifting point and the mean value of the sampling heights of all n lifting points, which is expressed as follows: ； The average of the sampling loads of all n lifting points is as follows: ； said load deviation AF i (t) is the real-time load value F carried by the lifting point i (t) is the absolute difference value between the real-time load value F carried by the lifting point and the average value of the load of all n lifting points, and is expressed as follows: 。 3. The equilibrium axis synchronization based fixed hoist type ship lock transit bridge lifting method according to claim 2, characterized in that, In operation, the PLC controller continuously records the height deviation ΔH i (t) the load deviation ΔF i (t) the trend over successive sampling periods, and performs the following recursive adjustment operation every N periods: ； ； wherein K p (t) represents the altitude error control gain coefficient at the current time t, K f (t) represents the load error control gain coefficient at the current time t, K p (t+Δt) represents the altitude error control gain coefficient at the next update, K f (t+Δt) represents the load error control gain coefficient at the next update, K represents the rate of change of the altitude deviation of the hoisting point i with respect to time, represents the rate of change of the load deviation of the hoisting point i with respect to time, γ1 represents the altitude error adjustment slope coefficient, and γ2 represents the load error adjustment slope coefficient.

4. The balanced axle synchronization based fixed hoist type ship lock transit bridge lifting method according to claim 1, characterized in that, The PLC controller adopts a main cycle and an auxiliary cycle parallel mechanism; The main cycle is used to execute a control algorithm main loop, including deviation calculation, speed instruction generation and data archiving; The auxiliary cycle is used to execute the following real-time self-checking tasks: displacement sensor and load sensor data mutation detection, bus communication state monitoring, driver running state diagnosis and emergency stop signal listening and logic response.

5. The balanced axle synchronization based fixed hoist type ship lock transit bridge lifting method according to claim 1, characterized in that, The displacement sensor is an absolute value encoder with power failure memory function, which records the last height value before power failure after abnormal power failure; The PLC controller reads all the code values when re-powered, and adjusts the zero offset uniformly through a reference height calibration algorithm.

6. The balanced axle synchronization based fixed hoist type ship lock transit bridge lifting method according to claim 3, characterized in that, Calculate the height change rate dH of the i-th suspension point within each sampling period. i / dt and the load change rate dF of the i-th lifting point i / dt, if the rate of change of height dH i / dt exceeds the maximum allowed threshold β H or load change rate dF i / dt exceeds the maximum allowed threshold β F Enter amplitude limiting compensation mode and limit the output speed before output: The maximum rate of change is limited by a rate limiting proportionality coefficient a max Limits and outliers are time-stamped for subsequent diagnostics.

7. The balanced axle synchronization based fixed hoist type ship lock transit bridge lifting method according to claim 1, characterized in that, Two groups of displacement sensors and load sensors are arranged at each driving adjustment lifting point, and each group of sensors is connected with the PLC controller through an independent channel; Two groups of displacement sensors and load sensors are simultaneously collected in a sampling period, and consistency comparison is performed by a PLC controller to calculate the deviation value δ sync If the deviation value δ sync exceeds the set value δ max , the following steps are performed: The current lifting point compensation is zeroed; The channel marker is switched to the backup in failure; The next cycle is automatically recalibrated.

8. A fixed hoist type lock bridge lifting system for implementing the fixed hoist type lock bridge lifting method based on synchronization of counterbalance axes according to any one of claims 1 to 7, characterized in that, The system comprises: A central drive rack is internally provided with a double-output-shaft reducer, the output shafts of the reducer are respectively connected with rigid transmission shafts through gear couplings at both ends of the output shafts; The transmission shafts pass through left and right hoist racks along the bridge body in the transverse direction and are connected with respective drum devices through drum couplings to realize rigid power transmission; Each drum device leads out a plurality of steel wire ropes, which are guided to respective automatic pulley structures through fixed pulleys, and the end of the lifting point is connected to a balance wheel mechanism, and two groups of the central drive racks and the hoist racks are arranged side by side to form a symmetrical four-point suspension closed loop system; A load sensor is installed at the shaft center of the balance wheel mechanism, and a displacement sensor is installed at the end of the drum to monitor the height and load information in the lifting process in real time; The PLC controller collects and analyzes the height and load data, calculates a variable frequency speed regulation compensation instruction according to the deviation amount when any lifting point deviates, and realizes four-point synchronous lifting control of the bridge body.

9. The fixed hoist ship lock vehicular bridge lifting system of claim 8, wherein, The system is also provided with a visual monitoring unit for collecting video images of the steel wire ropes to identify the wire breaking condition of the steel wire ropes.

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