Safety protection method for off-tracking prevention of a tongs type lifting device

Abstract

The present application belongs to the technical field of hoisting safety protection, and provides a safety protection method for a track-off prevention wheel of a tongs-type lifting appliance, which comprises: receiving a point-dynamic reversing instruction and reading a current inclination angle of a balance beam, directly executing a reversal if the angle is zero, otherwise, calculating an expected impact rotation of a hinged point according to a reversal torque, a current inclination angle and historical wear and load data, and comparing the expected impact rotation with a historically calibrated dead-stuck critical impact value to predict whether the hinged point will be dead-stuck, if it is determined that the hinged point will be dead-stuck, reversely solving a critical inclination angle allowed in a current working condition based on a calibrated corresponding relationship, combining a leveling speed to calculate a remaining adjustment time limit, and finally actively leveling the balance beam to within the critical angle within the time limit, and executing the point-dynamic reversing after confirming that the balance beam is in place. The present application actively predicts and limits the leveling time, and avoids the track-off of a walking wheel caused by the dead-stuck of a hinged point from the root, and improves the safety and reliability of point-dynamic reversing operation of the tongs-type lifting appliance.

Description

Technical Field

[0001] This invention belongs to the field of lifting safety protection technology, specifically a method for preventing derailment of the wheels of a clamp-type lifting device. Background Technology

[0002] Clamping-type spreaders typically mount their wheels on a swingable balance beam, which is connected to the chassis via hinge points to accommodate uneven tracks and chassis deformation. When there is a difference in track elevation, the balance beam will remain at a certain initial tilt angle for an extended period. If the operator executes a jog reversal command at this time, the lateral force on the wheels will instantly reverse, causing the hinge points to experience severe impact and rotation. If the hinge points are worn or poorly lubricated, this impact can easily cause them to jam. Once jammed, the balance beam will be unable to resume its free swing, and the wheel treads will become... Instead of being parallel to the track, the wheels are tilted and pressed against it. The direct consequence is that the wheels and the track experience severe sliding friction, causing the motor to overheat and trip. If operation continues, the wheels will grind the track head like a file, eventually leading to a derailment. Existing derailment protection systems mostly use static rail clamps or fixed-gap horizontal wheels, which cannot predict or cope with the impact jamming at the hinge point during momentary reversal. They lack proactive prediction and tilt adjustment methods based on real-time tilt angle and wear status, making it difficult to fundamentally prevent wheel derailment caused by hinge point jamming.

[0003] Therefore, the present invention provides a method for preventing derailment of wheels in a clamp-type lifting device. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, at least one technical problem raised in the background art is solved.

[0005] The technical solution adopted by this invention to solve its technical problem is: a method for preventing derailment of wheels in a clamp-type lifting device, comprising the following steps: S1: Receive the jog reverse command, read the current tilt angle of the balance beam. If the current tilt angle is zero, directly execute the jog reverse; otherwise, proceed to step S2. S2: Based on the reversing torque, current tilt angle, and historical wear and load data, calculate the expected impact rotation at the hinge point, and call up the critical impact values ​​for jamming at different tilt positions under historical calibration to compare and determine whether it will cause the hinge point to jam. S3: If this occurs, based on the correspondence between the historically calibrated impact rotation amount and the critical impact value of jamming, which has been verified in step S2, and combined with the current load and wear, the critical tilt angle allowed in the non-jammed state of the hinge point is solved in reverse, and the remaining adjustment time limit is calculated by combining the current tilt angle of the balance beam and the leveling speed. S4. Before the remaining adjustment time limit ends, adjust the tilt angle of the balance beam with the critical tilt angle as the target, and after confirming that it is in place, perform inching reverse.

[0006] As a further aspect of the present invention: the jog reversal refers to the operation mode in which the motor of the lifting device wheel is energized and rotates in the opposite direction within a preset short time (0.2 to 0.5 seconds), driving the lifting device to move a preset distance in the opposite direction.

[0007] As a further aspect of the present invention: the process of reading the current tilt angle of the balance beam is as follows: After receiving the inching reverse command in real time, the analog signal output by the non-contact angle sensor installed near the hinge point of the balance beam is read, filtered, and converted into the current tilt angle value. If the current tilt angle is not zero, the process proceeds to step S2.

[0008] As a further aspect of the present invention: the reversing torque is obtained in real time by a torque sensor installed between the motor output shaft and the transmission mechanism; Historical wear data includes the cumulative increase in the clearance of the hinge point bushing, which is obtained through online monitoring by displacement sensors installed at the hinge point; Load data is obtained by measuring the current load in real time using weighing sensors on the spreader.

[0009] As a further aspect of the present invention: the process of calculating the expected impact rotation at the hinge point is as follows: The hinge point is considered as an elastic hinge with equivalent torsional stiffness and equivalent damping, and the balance beam and wheel assembly have rotational inertia about the hinge axis. Based on rigid body dynamics, a single-degree-of-freedom torsional vibration equation is established. The peak impact rotation is obtained by solving the Laplace transform. The impact generated by the inching reversal is manifested as an instantaneous pulse torque. The instantaneous pulse torque reversal torque, the sine value of the current tilt angle, the ratio of the lever arm to the wheel radius, the load, the friction coefficient, and the wear correction factor are jointly determined. The peak impact rotation is converted into an angle value as the expected impact rotation.

[0010] As a further aspect of the present invention: the method for obtaining the critical impact value of jamming at different deflection positions under historical calibration is as follows: A fixed balance beam and hinge assembly are used to simulate different loads and wear conditions. A controllable instantaneous torsional impact is applied to the hinge, and the amount of impact rotation is recorded. Jamming is defined as the hinge being unable to return to its initial position within a preset error range by its own weight after the impact. With a fixed load and wear, the impact rotation is gradually increased until jamming occurs. The impact rotation at this point is recorded as the critical impact value. The test is repeated at different deflection positions to obtain the critical impact value for jamming at different deflection positions.

[0011] As a further aspect of the present invention: the process of comparing and determining whether it will cause the hinge point to jam is as follows: Based on the current load, wear amount, and current tilt angle, the corresponding critical impact value for jamming is retrieved from the historical calibration, and the product of the critical impact value for jamming and the safety factor is calculated. If the expected impact rotation is less than the product of the critical impact value for jamming and the safety factor, it is determined that jamming will not occur, and inching reverse is allowed. Conversely, if the expected impact rotation is greater than or equal to the product of the critical impact value for jamming and the safety factor, it is determined that jamming will occur, and step S3 is triggered.

[0012] As a further aspect of the present invention: the process of reversely solving for the critical tilt angle allowed in the non-jammed state of the hinge point is as follows: Obtain the current load and current wear; calculate the product of the expected impact rotation and the safety factor as the maximum allowable impact rotation; based on the critical impact values ​​under different loads, wear, and initial tilt angles in historical calibration, fix the current load and current wear, and use a binary search method to traverse the jamming critical impact values ​​corresponding to different tilt angles, find the maximum tilt angle when the jamming critical impact value is exactly greater than or equal to the maximum allowable impact rotation, which is the critical tilt angle allowed in the non-jammed state of the hinge point.

[0013] As a further aspect of the present invention: the process of calculating the remaining adjustment time limit by combining the current tilt angle of the balance beam and the leveling speed is as follows: Calculate the deviation between the current tilt angle and the critical tilt angle of the balance beam to obtain the angle to be adjusted; The ratio between the angle to be adjusted and the leveling speed is calculated to obtain the theoretical adjustment time. The leveling speed is the rate at which the leveling actuator changes the angle per unit time when actively adjusting the tilt angle of the balance beam, which is obtained from the factory calibration. Multiply the theoretical adjustment time by the preset response delay coefficient to obtain the remaining adjustment time limit.

[0014] As a further aspect of the present invention: the process of adjusting the tilt angle of the balance beam with the critical tilt angle as the target before the end of the remaining adjustment time limit is as follows: Using the critical tilt angle as the target value, the current angle of the tilt sensor is read in real time to make the current angle reach the critical tilt angle; If the remaining adjustment time exceeds the set upper limit, an overtime alarm will be triggered and the reversal operation will be suspended, prompting the operator to check the leveling mechanism or take manual intervention measures.

[0015] The beneficial effects of this invention are as follows: By real-time detection of the inching reversal command and reading the current tilt angle of the balance beam, it quickly determines whether there are preconditions that could lead to subsequent impact jamming. When the tilt angle is non-zero, the subsequent protection process is triggered, thereby identifying the risk of impact jamming without affecting normal operation; the actual working condition parameters such as reversal torque, current tilt angle, load, and wear are quantified into the expected impact rotation of the hinge point, and quantitatively compared with the historically calibrated jamming threshold value, achieving accurate prediction of the risk of hinge point jamming at the moment of inching reversal, providing a basis for whether to initiate active leveling; the current load and wear are obtained through reverse solving. The system sets a minimum allowable critical tilt angle and calculates the remaining adjustment time based on the leveling speed. This transforms the qualitative judgment of whether the system is stuck into a quantitative execution parameter for adjusting the tilt angle within a specified time limit, avoiding blind leveling or excessively slow leveling that could lead to protection failure. The system actively adjusts the attitude of the balance beam with the critical tilt angle as the target, and only releases the inching reverse command after confirming that it is in place. This eliminates the risk of impact jamming caused by the tilt of the hinge point from the root. At the same time, it sets an overtime alarm and upper limit protection mechanism to prevent infinite waiting or secondary accidents due to leveling mechanism failure. Ultimately, it ensures that the wheels are always in a normal state of parallel rail pressure, realizing a closed loop of safety protection for the clamp-type spreader's anti-derailment wheels. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a flowchart illustrating the steps of a method for preventing derailment of wheels in a clamp-type lifting device according to an embodiment of the present invention. Figure 2 This is a logic diagram of a method for preventing derailment of wheels in a clamp-type lifting device according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the anti-derailment wheel safety protection system of a clamp-type lifting device according to Embodiment 2 of the present invention. Detailed Implementation

[0018] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0019] Example: Please refer to Figure 1-2 As shown in the embodiment of the present invention, a method for preventing derailment of the wheels of a clamp-type lifting device includes the following steps: S1: Receive the jog reverse command, read the current tilt angle of the balance beam. If the current tilt angle is zero, directly execute the jog reverse; otherwise, proceed to step S2. In step S1, "jog reversal" refers to the operation mode in which the motor of the spreader wheel is energized and rotates in the opposite direction for a very short time (usually 0.2 to 0.5 seconds), driving the spreader to move a small distance (a few centimeters to tens of centimeters) in the opposite direction; In step S1, the process of receiving the jog reversal command and reading the current tilt angle of the balance beam is as follows: After receiving the jog reversal command in real time, the analog signal output by the non-contact angle sensor (such as magnetostrictive or MEMS inclinometer) installed near the hinge point of the balance beam is read at a frequency of not less than 10Hz, and then converted into the current tilt angle value θ (unit: degree, accurate to 0.1°) after filtering. The method for converting the analog quantity into the current tilt angle value θ is calculated based on the standard sensor linear conversion formula: ; in, For the real-time output current value of the sensor, The current corresponding to the lower limit of the sensor's range, The current corresponding to the upper limit of the sensor's range, The angle corresponding to the lower limit of the range. This is the angle corresponding to the upper limit of the measurement range; For example, for analog quantities: given the sensor range (e.g., 4mA corresponds to -10°, 20mA corresponds to +10°), the linear transformation formula is used: , This indicates the real-time output current value of the sensor; In step S1, if the current tilt angle is zero, the jog reversal is performed directly; if the current tilt angle is not zero, it is counted in step S2. Understandably, the significance of step S1 is as follows: by real-time detection of the inching reversal command and reading the current tilt angle of the balance beam, it can quickly determine whether there are preconditions that could lead to subsequent impact jamming; when the tilt angle is zero, it directly executes the reversal, avoiding unnecessary calculations and delays, and ensuring normal operating efficiency; when the tilt angle is non-zero, it triggers the subsequent protection process, thereby identifying the risk of impact jamming without affecting normal operation. S2: Based on the reversing torque, current tilt angle, and historical wear and load data, calculate the expected impact rotation at the hinge point, and call up the critical impact values ​​for jamming at different tilt positions under historical calibration to compare and determine whether it will cause the hinge point to jam. In step S2, the reverse torque, current tilt angle, and historical wear and load data are obtained as follows: The torque is measured in real time by a torque sensor installed between the motor output shaft and the transmission mechanism. The sensor outputs a 4~20mA analog signal, which is sampled by the controller and converted into a torque value (unit: N·m). The current tilt angle has been acquired in step S1. It is obtained by filtering and converting the analog signal output by a non-contact angle sensor (such as a magnetostrictive or MEMS tiltmeter) installed near the hinge point of the balance beam. Historical wear data includes the cumulative increase in the clearance of the hinge point bushing (unit: mm), which is monitored online by a displacement sensor installed near the hinge point; Load data is measured in real time by weighing sensors (such as pressure pins or tension / compression sensors) on the spreader to measure the current load (unit: kN or t), and the historical load spectrum (maximum value, average value, number of fluctuations) is recorded at the same time. In step S2, the specific process for calculating the expected impact rotation at the hinge point is as follows: When a hinge point is subjected to a momentary reverse impact, its rotational behavior is represented as a single-degree-of-freedom torsional vibration. The theoretical basis is rigid body dynamics and the balance of impact torque, and the hinge point is considered to have equivalent torsional stiffness. (N·m / rad) and equivalent damping A flexible hinge with a moment of inertia of (N·m·s / rad); the moment of inertia of the balance beam and wheel assembly about the hinge axis is... (kg·m²); The impact generated by the inching reversal is manifested as an instantaneous pulse torque. (N·m); the kinetic equation is: ;

[0020] in, The equivalent impact torque converted from the reverse torque. This represents the angular displacement at the hinge point, that is, the rotation angle of the equilibrium beam about the hinge axis relative to its initial equilibrium position. It represents angular velocity (rad / s). Angular acceleration (rad / s²) is represented. Based on the dynamic equations and solved using the Laplace transform, the peak impact rotation is... (Unit: rad) can be expressed as: ;

[0021] Impact torque From reverse torque Current tilt angle Load and wear Joint decision: ;

[0022] in, The lever arm (m) representing the distance from the point of application of the torque to the center of the hinge point is a structurally fixed value. Indicates the radius of the wheel (m). Indicates the coefficient of friction at the hinge point. The lever arm correction factor, representing the effect of wear, was calibrated experimentally. in, The experimental calibration method is: wear correction factor Calibration was performed using offline experiments at different wear levels. Under these conditions, a known impact torque is applied to the balance beam, and the actual impact rotation is measured to establish a wear correction factor. With wear The corresponding relationship table allows for direct lookup of the wear correction factor based on the current wear level during online operation. ; The final expected impact rotation is: ;

[0023] The derivation process of the final expected impact rotation is as follows: Based on the dynamic equation: ; Performing a Laplace transform yields the system transfer function: ; For instantaneous pulse torque, ( (where the function is a unit impulse function), its Laplace transform is: Substituting, we get: ; Performing the inverse Laplace transform yields the time-domain response: ; The peak impact rotation is: ; Furthermore, impact torque From reverse torque Current tilt angle Load and wear Joint decision: ; Will Substituting into the formula for peak impact rotation and converting radians to degrees, we get: ;

[0024] In step S2, the critical impact value for jamming at different deflection positions under historical calibration is obtained as follows: A1. Fix the balance beam and hinge assembly on the test bench to simulate different loads (graded loading) and different wear conditions (by replacing bushings with different clearances). A2, apply a controllable instantaneous torsional impact to the hinge point (by means of hydraulic impact hammer or motor reverse emergency stop), and record the amount of impact rotation; A3, defined as jamming as the hinge point being unable to return to its initial position within ±0.5° within 0.5 seconds by its own weight after impact; A4. With a fixed load and wear amount, gradually increase the impact rotation until jamming occurs. Record the impact rotation amount, which is the critical impact value under the current load, wear amount, and initial tilt angle. Repeat the above test for different tilt positions (i.e., different initial tilt angles) to obtain the jamming critical impact value for different tilt positions. In step S2, the process of comparing and determining whether it will cause the hinge point to jam is as follows: Based on the current load, wear level, and current tilt angle, the corresponding critical jamming impact value CJ is invoked. 临界 and the expected impact rotation CJ 预期 The comparison and judgment process is as follows: If CJ 预期 <CJ 临界 If *k (k is a safety factor, with a value of 0.8~0.9) is used, it is determined that the hinge point will not be stuck, and the inching reversal can be performed directly. If CJ 预期 ≥CJ 临界 If *k is detected, it will cause the hinge point to jam, triggering step S3. It should be noted that the safety factor K is used to reserve a margin to avoid misjudgment or missed judgment near the critical value. The measurement error of sensors such as torque, angle, and load is ±1% to ±5%; the calculation model of the expected impact rotation also has an engineering error within ±15%. Taking K=0.8~0.9 can provide a safety margin of 10%~20%, avoiding misjudgment (judging that it should be stuck but not stuck) or missed judgment (triggering leveling when it should not be stuck) due to errors. In the field of crane safety protection, a safety factor of 0.8~0.9 is usually used, which is in line with the recommended range of safety margin in GB / T 3811-2008 "Crane Design Code". Understandably, the significance of step S2 lies in: introducing a single-degree-of-freedom torsional vibration dynamics model, quantifying actual working condition parameters such as reversal torque, current tilt angle, load, and wear into the expected impact rotation of the articulation point, and making a quantitative comparison with the historically calibrated jamming critical value. This breaks through the limitation of traditional anti-derailment devices being unable to predict dynamic impacts, and achieves accurate prediction of the risk of articulation point jamming at the moment of inching reversal, providing a basis for whether to initiate active leveling. S3, if this occurs, then based on the correspondence between the historically calibrated impact rotation amount and the critical impact value of jamming, which has been verified in step S2, and combined with the current load and wear, the critical tilt angle allowed in the non-jammed state of the hinge point is solved in reverse, and the remaining adjustment time limit is calculated by combining the current tilt angle of the balance beam and the leveling speed. In step S3, the process of reversely solving for the critical tilt angle allowed in the non-jammed state of the hinge point is as follows: Obtain current operating parameters, and read the current load (from the weighing sensor) and current wear (cumulative record); The product of the expected impact rotation calculated in step S2 and the safety factor (0.8~0.9) is taken as the maximum allowable impact rotation. Based on the critical impact values ​​under different loads, wear amounts, and initial tilt angles in historical calibration, the current load and current wear amount are fixed. The critical impact values ​​corresponding to different tilt angles under the current load and wear combination are traversed. The binary search method is used to find the maximum tilt angle when the critical impact value of jamming is just greater than or equal to the maximum allowable impact rotation amount. This is the critical tilt angle allowed in the non-jammed state of the hinge point. In step S3, the process of calculating the remaining adjustment time limit by combining the current tilt angle of the balance beam and the leveling speed is as follows: By calculating the deviation between the current tilt angle of the balance beam and the critical tilt angle allowed when the hinge point is not stuck, the angle to be adjusted is obtained: current tilt angle of the balance beam - critical tilt angle. The ratio of the angle to be adjusted to the leveling speed is calculated to obtain the theoretical adjustment time. The leveling speed refers to the rate at which the leveling actuator (such as a hydraulic cylinder, electric push rod, or lead screw) changes the angle per unit time when actively adjusting the tilt angle of the balance beam. The unit is degrees per second (° / s) and is calibrated by the factory. Based on the theoretical adjustment time and combined with the institutional response delay, the remaining adjustment time limit is calculated as follows: Remaining adjustment time limit = Theoretical time × 1.2 (with 20% reserved for institutional response delay). It should be noted that the basis for reserving 20% ​​for mechanism response delay is as follows: In industry standards such as heavy-duty automation (dynamic load factor is usually taken as 1.2-1.5) and crane design (lifting dynamic load factor is taken as 1.2-1.5), 1.2-1.5 is the conventional range of dynamic load factor values ​​to ensure safety; It is understandable that the specific process of step S3 is as follows: using the correspondence between the impact rotation amount and the critical value calibrated in step S2, the critical tilt angle allowed under the current load and wear is obtained by reverse solution, and the remaining adjustment time limit is calculated based on the leveling speed. The qualitative judgment of whether it is stuck is transformed into a quantitative execution parameter for completing the tilt angle adjustment within the specified time limit, so that the active intervention is operable and timely, and avoids protection failure caused by blind leveling or slow leveling. S4. Before the remaining adjustment time limit ends, adjust the tilt angle of the balance beam with the critical tilt angle as the target, and after confirming that it is in place, perform inching reverse. In step S4, before the remaining adjustment time limit expires, the current tilt angle of the balance beam is adjusted to the critical tilt angle with the critical tilt angle as the target, and then the inching reverse is performed; It should be noted that if the remaining adjustment time exceeds the set upper limit (e.g., 5 seconds), the adjustment will not be initiated, inching reverse will be prohibited, and the operator will be prompted to check the leveling mechanism or use manual intervention. The set upper limit (e.g., 5 seconds) is used to prevent indefinite waiting due to serious malfunctions of the leveling mechanism (e.g., jamming, leakage, motor damage), thereby avoiding long-term operation interruption or secondary accidents. Understandably, the significance of step S4 lies in: within the strict remaining adjustment time limit, actively adjusting the attitude of the balance beam with the critical tilt angle as the target, and only releasing the inching reverse command after confirming that it is in place, thus eliminating the risk of impact jamming caused by the misalignment of the hinge point from the root. At the same time, an overtime alarm and upper limit protection mechanism are set to prevent indefinite waiting or secondary accidents due to the failure of the leveling mechanism, ultimately ensuring that the wheels are always in a normal state of parallel rail pressing, realizing a safety protection closed loop for the clamp-type spreader to prevent the wheels from derailing.

[0025] Example 2: Please refer to Figure 3 As shown in the embodiment of the present invention, a safety protection system for the anti-derailment wheel of a clamp-type lifting device includes the following modules: Inclination detection module: Receives jog reverse command, reads the current tilt angle of the balance beam, if the current tilt angle is zero, directly executes jog reverse, otherwise enters the step impact prediction module; Impact prediction module: Based on the reversal torque, current tilt angle and historical wear and load data, calculate the expected impact rotation of the hinge point, and call the critical impact value of jamming at different tilt positions under historical calibration to compare and judge whether it will cause the hinge point to jam. The specific process for calculating the expected impact rotation at the hinge point is as follows: When a hinge point is subjected to a momentary reverse impact, its rotational behavior is represented as a single-degree-of-freedom torsional vibration. The theoretical basis is rigid body dynamics and the balance of impact torque, and the hinge point is considered to have equivalent torsional stiffness. (N·m / rad) and equivalent damping A flexible hinge with a moment of inertia of (N·m·s / rad); the moment of inertia of the balance beam and wheel assembly about the hinge axis is... (kg·m²); The impact generated by the inching reversal is manifested as an instantaneous pulse torque. (N·m); the kinetic equation is: ;

[0026] in, The equivalent impact torque converted from the reverse torque. This represents the angular displacement at the hinge point, that is, the rotation angle of the equilibrium beam about the hinge axis relative to its initial equilibrium position. It represents angular velocity (rad / s). Angular acceleration (rad / s²) is represented. Based on the dynamic equations and solved using the Laplace transform, the peak impact rotation is... (Unit: rad) can be expressed as: ;

[0027] Impact torque From reverse torque Current tilt angle Load and wear Joint decision: ;

[0028] in, The lever arm (m) representing the distance from the point of application of the torque to the center of the hinge point is a structurally fixed value. Indicates the radius of the wheel (m). Indicates the coefficient of friction at the hinge point. The lever arm correction factor, representing the effect of wear, was calibrated experimentally. in, The experimental calibration method is as follows: the balance beam is fixed on the test bench, and a known impact torque is applied. Record the actual impact rotation amount The formula can be reversed to obtain: ; The final expected impact rotation is: ;

[0029] The method for obtaining the critical impact value of jamming at different deflection positions under historical calibration is as follows: A1. Fix the balance beam and hinge assembly on the test bench to simulate different loads (graded loading) and different wear conditions (by replacing bushings with different clearances). A2, apply a controllable instantaneous torsional impact to the hinge point (by means of hydraulic impact hammer or motor reverse emergency stop), and record the amount of impact rotation; A3, defined as jamming as the hinge point being unable to return to its initial position within ±0.5° within 0.5 seconds by its own weight after impact; A4. With a fixed load and wear amount, gradually increase the impact rotation until jamming occurs. Record the impact rotation amount, which is the critical impact value under the current load, wear amount, and initial tilt angle. Repeat the above test for different tilt positions (i.e., different initial tilt angles) to obtain the jamming critical impact value for different tilt positions. The process of comparing and determining whether the hinge point will get stuck is as follows: Based on the current load, wear level, and current tilt angle, the corresponding critical jamming impact value CJ is invoked. 临界 and the expected impact rotation CJ 预期 The comparison and judgment process is as follows: If CJ 预期 <CJ 临界 If *k (k is a safety factor, with a value of 0.8~0.9) is used, it is determined that the hinge point will not be stuck, and the inching reversal can be performed directly. If CJ 预期 ≥CJ 临界 If *k is used, it will cause the hinge point to jam. If the critical back-calculation module is triggered, it will calculate the critical tilt angle allowed in the non-jammed state of the hinge point by inversely based on the correspondence between the impact rotation amount and the jamming critical impact value that has been historically calibrated in the impact prediction module, combined with the current load and wear. It will also calculate the remaining adjustment time limit by combining the current tilt angle of the balance beam and the leveling speed. The process of reverse-engineering the critical tilt angle allowed when the hinge point is not stuck is as follows: Obtain current operating parameters, and read the current load (from the weighing sensor) and current wear (cumulative record); Calculate the product of the expected impact rotation and the safety factor (0.8~0.9) as the maximum allowable impact rotation; Based on the critical impact values ​​under different loads, wear amounts, and initial tilt angles in historical calibration, the current load and current wear amount are fixed. The critical impact values ​​corresponding to different tilt angles under the current load and wear combination are traversed. The binary search method is used to find the maximum tilt angle when the critical impact value of jamming is just greater than or equal to the maximum allowable impact rotation amount. This is the critical tilt angle allowed in the non-jammed state of the hinge point. The process of calculating the remaining adjustment time limit by combining the current tilt angle of the balance beam and the leveling speed is as follows: By calculating the deviation between the current tilt angle of the balance beam and the critical tilt angle allowed when the hinge point is not stuck, the angle to be adjusted is obtained: current tilt angle of the balance beam - critical tilt angle. The ratio of the angle to be adjusted to the leveling speed is calculated to obtain the theoretical adjustment time. The leveling speed refers to the rate at which the leveling actuator (such as a hydraulic cylinder, electric push rod, or lead screw) changes the angle per unit time when actively adjusting the tilt angle of the balance beam. The unit is degrees per second (° / s) and is calibrated by the factory. Based on the theoretical adjustment time and combined with the institutional response delay, the remaining adjustment time limit is calculated as follows: Remaining adjustment time limit = Theoretical time × 1.2 (with 20% reserved for institutional response delay). The leveling execution module adjusts the tilt angle of the balance beam with the critical tilt angle as the target before the remaining adjustment time limit ends, and performs jogging reversal after confirming that it is in place.

[0030] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preventing derailment of wheels in a clamp-type lifting device, characterized in that: Includes the following steps: S1: Receive the jog reverse command, read the current tilt angle of the balance beam. If the current tilt angle is zero, directly execute the jog reverse; otherwise, proceed to step S2. Inching reverse refers to the operation mode in which the motor of the spreader wheel is energized and rotates in the opposite direction within a preset short time, driving the spreader to move a preset distance in the opposite direction; S2: Based on the reversing torque, current tilt angle, and historical wear and load data, calculate the expected impact rotation at the hinge point, and call up the critical impact value for jamming at different tilt positions under historical calibration to compare and determine whether it will cause the hinge point to jam; the balance beam is connected to the frame through the hinge point; The reversal torque is obtained in real time by a torque sensor installed between the motor output shaft and the transmission mechanism. Historical wear data includes the cumulative increase in the clearance of the hinge point bushing, which is obtained through online monitoring by displacement sensors installed at the hinge point; Load data is obtained by measuring the current lifting weight in real time through the weighing sensors on the spreader. S3: If this occurs, based on the correspondence between the historically calibrated impact rotation amount and the critical impact value of jamming, which has been verified in step S2, and combined with the current load and wear, the critical tilt angle allowed in the non-jammed state of the hinge point is solved in reverse, and the remaining adjustment time limit is calculated by combining the current tilt angle of the balance beam and the leveling speed. S4: Before the remaining adjustment time limit ends, adjust the tilt angle of the balance beam with the critical tilt angle as the target, and after confirming that it is in place, perform inching reverse.

2. The method for preventing derailment of the wheels of a clamp-type lifting device according to claim 1, characterized in that: The process of reading the current tilt angle of the balance beam is as follows: After receiving the inching reverse command in real time, the analog signal output by the non-contact angle sensor installed near the hinge point of the balance beam is read, filtered, and converted into the current tilt angle value. If the current tilt angle is not zero, the process proceeds to step S2.

3. The method for preventing derailment of the wheels of a clamp-type lifting device according to claim 1, characterized in that: The process of calculating the expected impact rotation at the hinge point is as follows: The hinge point is considered as an elastic hinge with equivalent torsional stiffness and equivalent damping, and the balance beam and wheel assembly have rotational inertia about the hinge axis. Based on rigid body dynamics, a single-degree-of-freedom torsional vibration equation is established. The peak impact rotation is obtained by solving the Laplace transform. The impact generated by the inching reversal is manifested as an instantaneous pulse torque. The instantaneous pulse torque reversal torque, the sine value of the current tilt angle, the ratio of the lever arm to the wheel radius, the load, the friction coefficient, and the wear correction factor are jointly determined. The peak impact rotation is converted into an angle value as the expected impact rotation.

4. The method for preventing derailment of the wheels of a clamp-type lifting device according to claim 3, characterized in that: The method for obtaining the critical impact value of jamming at different deflection positions under historical calibration is as follows: A fixed balance beam and hinge assembly are used to simulate different loads and wear conditions. A controllable instantaneous torsional impact is applied to the hinge, and the amount of impact rotation is recorded. Jamming is defined as the hinge being unable to return to its initial position within a preset error range by its own weight after the impact. With a fixed load and wear, the impact rotation is gradually increased until jamming occurs. The impact rotation at this point is recorded as the critical impact value. The test is repeated at different deflection positions to obtain the critical impact value for jamming at different deflection positions.

5. The method for preventing derailment of the wheels of a clamp-type lifting device according to claim 4, characterized in that: The process of comparing and determining whether the hinge point will get stuck is as follows: Based on the current load, wear, and tilt angle, the corresponding critical impact value for jamming is retrieved from the historical calibration, and the product of the critical impact value for jamming and the safety factor is calculated. If the expected impact rotation is less than the product of the critical impact value for jamming and the safety factor, it is determined that jamming will not occur, and inching reverse is allowed. Conversely, if the expected impact rotation is greater than or equal to the product of the critical impact value for jamming and the safety factor, it is determined that jamming will occur, and step S3 is triggered.

6. The method for preventing derailment of the wheels of a clamp-type lifting device according to claim 1, characterized in that: The process of reverse-engineering the critical tilt angle allowed when the hinge point is not stuck is as follows: Obtain the current load and current wear; calculate the product of the expected impact rotation and the safety factor as the maximum allowable impact rotation; based on the critical impact values ​​under different loads, wear, and initial tilt angles in historical calibration, fix the current load and current wear, and use a binary search method to traverse the jamming critical impact values ​​corresponding to different tilt angles, find the maximum tilt angle when the jamming critical impact value is exactly greater than or equal to the maximum allowable impact rotation, which is the critical tilt angle allowed in the non-jammed state of the hinge point.

7. A method for preventing derailment of wheels in a clamp-type lifting device according to claim 6, characterized in that: The process of calculating the remaining adjustment time limit by combining the current tilt angle of the balance beam and the leveling speed is as follows: Calculate the deviation between the current tilt angle and the critical tilt angle of the balance beam to obtain the angle to be adjusted; The theoretical adjustment time is obtained by calculating the ratio between the angle to be adjusted and the leveling speed; where the leveling speed is the rate at which the leveling actuator changes the angle per unit time when actively adjusting the tilt angle of the balance beam, which is obtained from the factory calibration. Multiply the theoretical adjustment time by the preset response delay coefficient to obtain the remaining adjustment time limit.

8. A method for preventing derailment of wheels in a clamp-type lifting device according to claim 7, characterized in that: Before the remaining adjustment time expires, the process of adjusting the tilt angle of the balance beam with the critical tilt angle as the target is as follows: Using the critical tilt angle as the target value, the current angle of the tilt sensor is read in real time to make the current angle reach the critical tilt angle; If the remaining adjustment time exceeds the set upper limit, an overtime alarm will be triggered and the reversal operation will be suspended, prompting the operator to check the leveling mechanism or take manual intervention measures.

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