A method for detecting the equivalent length of a weight for anti-roll control

Abstract

The application discloses a weight equivalent swing length detection method for anti-swing control, comprising the following steps: lifting a lifting tool with a weight to an upper limit position of a lifting mechanism; measuring a first swing period of the weight at the upper limit position, and obtaining a first equivalent swing length based on the first swing period; lowering the lifting tool with the weight to a stop position at a preset distance from the ground, obtaining a position deviation value relative to the upper limit position based on a real-time speed of the lowering action; measuring a second swing period of the weight at the stop position, and obtaining a second equivalent swing length based on the second swing period; obtaining an equivalent swing length change speed based on the real-time speed of the lowering action, the first equivalent swing length, the position deviation value and the second equivalent swing length; and obtaining a real-time equivalent swing length of the weight based on the equivalent swing length change speed. The problem that the existing detection method cannot accurately and timely detect the equivalent swing length of the weight lifted by the crane is solved.

Description

Technical Field

[0001] This invention relates to the field of anti-sway control technology, and more specifically to a method for detecting the equivalent pendulum length of a heavy object for anti-sway control. Background Technology

[0002] Currently, in order to improve the loading and unloading efficiency and safety of cranes, anti-sway control technology has become a key technology to suppress the swaying of heavy objects in the direction of the trolley and hoisting mechanism. The anti-sway control technology is based on the single pendulum control principle. In the actual operation of the crane, the trolley, hoisting mechanism and the main trolley need to work together to achieve anti-sway, that is, anti-sway by changing the pendulum length. It is inevitable to detect the key variable of the equivalent pendulum length in real time. The traditional crane pendulum length detection method uses an absolute encoder or an incremental encoder to detect the length of the wire rope between the hoisting drum (i.e. the fulcrum of the swing) and the heavy object, and uses this length as the pendulum length for the anti-sway control algorithm.

[0003] However, while the equivalent pendulum length obtained by traditional detection methods is relatively accurate for ordinary single-girder bridge cranes, it is less accurate for complex cranes such as port container gantry cranes. These cranes typically use spreaders to lift containers, and the spreaders are quite large. Multiple wire ropes from the hoisting drum are connected to pulleys distributed at the four corners of the spreader. In this structural configuration, the equivalent pendulum length obtained by traditional detection methods will deviate significantly from the equivalent pendulum length actually required by the anti-sway control algorithm, greatly reducing the effectiveness of suppressing the swaying of the load. In addition, to save costs or due to structural dimensions and external environmental factors, the hoisting mechanism is not equipped with an encoder, making real-time detection of the equivalent pendulum length even more difficult.

[0004] Therefore, how to accurately and in real time detect the equivalent pendulum length of the load lifted by the crane is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for detecting the equivalent pendulum length of a heavy object for anti-sway control, which solves the problem that existing detection methods cannot accurately detect the equivalent pendulum length of a heavy object lifted by a crane in real time.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for detecting the equivalent pendulum length of a heavy object for anti-sway control, comprising:

[0008] Raise the lifting device with the load attached to the upper limit position of the hoisting mechanism;

[0009] Measure the first swing period of the weight at the upper limit position, and obtain the first equivalent pendulum length based on the first swing period;

[0010] The lifting device with the load is lowered to a stop position at a preset distance from the ground, the real-time speed of the descent is obtained, and the position deviation value relative to the upper limit position is obtained based on the real-time speed of the descent.

[0011] Measure the second swing period of the weight at the stop position, and obtain the second equivalent pendulum length based on the second swing period;

[0012] The rate of change of the equivalent pendulum length is obtained based on the real-time speed of the descent, the first equivalent pendulum length, the position deviation value, and the second equivalent pendulum length.

[0013] The real-time equivalent pendulum length of the weight is obtained based on the rate of change of the equivalent pendulum length.

[0014] Preferably, raising the lifting device with the load attached to it to the upper limit position of the hoisting mechanism specifically includes:

[0015] The hoisting motor is controlled to rotate forward by the hoisting frequency converter. The hoisting motor drives the reducer to rotate, and the reducer drives the hoisting drum to rotate. The hoisting drum drives the lifting device to rise through the wire rope. After receiving the upper limit position signal, the hoisting frequency converter controls the hoisting motor to stop.

[0016] Preferably, lowering the lifting device carrying the heavy object to a stop position at a preset distance from the ground specifically includes:

[0017] The hoisting motor is controlled to reverse by the hoisting frequency converter. The hoisting motor drives the reducer to rotate, and the reducer drives the hoisting drum to rotate. The hoisting drum drives the lifting device to descend through the wire rope until it reaches a stop position at a preset distance from the ground.

[0018] Preferably, the position deviation value is represented by H, and the calculation formula is as follows:

[0019] H = ∫(v)dt, where v represents the real-time velocity of the descent motion.

[0020] Preferably, the real-time speed v of the descent action is synchronized with the real-time operating frequency f of the hoisting motor controlled by the hoisting frequency converter. cmd They are directly proportional, and the conversion formula is as follows:

[0021]

[0022] Among them, F norm This indicates the rated frequency of the hoisting motor, v. norm f represents the lifting speed of the lifting mechanism corresponding to the rated frequency of the lifting motor. cmd This indicates the real-time operating frequency of the hoisting motor controlled by the hoisting frequency converter.

[0023] Preferably, the formula for calculating the equivalent pendulum length change rate v1 is as follows:

[0024] Where L1 represents the first equivalent pendulum length and L2 represents the second equivalent pendulum length.

[0025] Preferably, obtaining the first equivalent pendulum length based on the first swing period and the second equivalent pendulum length based on the second swing period specifically includes:

[0026] The formula for calculating the equivalent pendulum length based on the swing period is:

[0027] Where L i Let T represent the equivalent pendulum length of the i-th pendulum. i Let represent the i-th oscillation period, g represent the gravitational acceleration with a value of 9.8, and π represent pi with a value of 3.14.

[0028] Preferably, the first swing period and the second swing period refer to the time taken for the weight to swing from the highest point on the left to the highest point on the right, and then back from the highest point on the right to the highest point on the left, when the weight is in different positions.

[0029] Preferably, the real-time equivalent pendulum length is L. s The calculation formula is as follows:

[0030]

[0031] Preferably, the lifting mechanism rises, f cmd Take the negative value, and the real-time equivalent pendulum length L s Smaller; the lifting mechanism descends, f cmd Take a positive value, and calculate the real-time equivalent pendulum length L. s It gets bigger.

[0032] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method for detecting the equivalent pendulum length of a heavy object for anti-sway control. The method calculates the change rate of the equivalent pendulum length during the rise or fall based on the real-time speed of the crane's hoisting mechanism, and then performs an integral calculation on the change rate to obtain an accurate real-time equivalent pendulum length. The detection method of the present invention does not require the addition of external sensors. It can obtain the equivalent pendulum length of the heavy object when the crane is performing anti-sway control in the direction of the trolley or the crane using the existing electronic control system of the crane. The operation process is simple and highly practical. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0034] Figure 1 The attached figure is a flowchart of the detection method provided by the present invention.

[0035] Figure 2 The attached figure is a schematic diagram of data calibration and parameter setting during the debugging phase provided by the present invention.

[0036] Figure 3 The attached figure is a schematic diagram of the swing trajectory provided by the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] like Figure 1 As shown, this embodiment of the invention discloses a method for detecting the equivalent pendulum length of a heavy object for anti-sway control, comprising:

[0039] Raise the lifting device with the load attached to the upper limit position of the hoisting mechanism;

[0040] Measure the first swing period of the weight at the upper limit position, and obtain the first equivalent pendulum length based on the first swing period;

[0041] The lifting device with the load is lowered to a stop position at a preset distance from the ground, the real-time speed of the descent is obtained, and the position deviation value relative to the upper limit position is obtained based on the real-time speed of the descent.

[0042] Measure the second swing period of the weight at the stop position, and obtain the second equivalent pendulum length based on the second swing period;

[0043] The rate of change of the equivalent pendulum length is obtained based on the real-time speed of the descent, the first equivalent pendulum length, the position deviation value, and the second equivalent pendulum length.

[0044] The real-time equivalent pendulum length of the weight is obtained based on the rate of change of the equivalent pendulum length.

[0045] Another embodiment of the present invention discloses a method for detecting the equivalent pendulum length of a heavy object for anti-sway control, comprising:

[0046] like Figure 2 As shown, the data calibration and parameter settings during the debugging phase are as follows:

[0047] Raise the lifting device with the load attached to the upper limit position of the hoisting mechanism;

[0048] Preferably, the hoisting motor is controlled to rotate forward by the hoisting frequency converter, the hoisting motor drives the reducer to rotate, the reducer drives the hoisting drum to rotate, and the hoisting drum drives the lifting device to rise through the wire rope. After receiving the upper limit position signal, the hoisting frequency converter controls the hoisting motor to stop.

[0049] Measure the first swing period of the weight at the upper limit position, and obtain the first equivalent pendulum length based on the first swing period;

[0050] Preferably, the first swaying cycle of the heavy object in the direction of the trolley at the upper limit position is measured. The trolley frequency converter does not activate the anti-sway algorithm. First, the trolley is controlled to move in jog mode, and then the trolley is controlled to stop. After the trolley stops, the heavy object will sway left and right in the direction of the trolley.

[0051] Preferred, such as Figure 3 As shown, the swing period refers to the time it takes for a weight to swing from its highest point on the left to its highest point on the right, and then back from its highest point on the right to its highest point on the left.

[0052] Preferably, the first swing cycle refers to the time taken for the weight to swing from the highest point on the left to the highest point on the right, and then back from the highest point on the right to the highest point on the left when it is at the upper limit position.

[0053] Preferably, the first swing period is measured five times with a stopwatch and the average value is taken as the final first swing period T1, which makes the measurement of the first swing period more accurate.

[0054] Preferably, the formula for calculating the first equivalent pendulum length L1 is: g represents the acceleration due to gravity, with a value of 9.8, and π represents pi, with a value of 3.14.

[0055] The lifting device with the load is lowered to a stop position at a preset distance from the ground, the real-time speed of the descent is obtained, and the position deviation value relative to the upper limit position is obtained based on the real-time speed of the descent.

[0056] The hoisting motor is reversed by the hoisting frequency converter, which drives the reducer to rotate. The reducer drives the hoisting drum to rotate, and the hoisting drum lowers the lifting device through the wire rope until it stops at a position 0.5 meters above the ground.

[0057] Preferably, a position deviation value H relative to the upper limit position is obtained by integral calculation based on the real-time speed of the hoisting mechanism's descent action. The calculation formula is as follows:

[0058] H = ∫(v)dt, where v represents the real-time velocity of the descent motion.

[0059] Preferably, the position deviation value H represents the height of the spreader from the upper limit position, and also represents the range of the spreader's height in the lifting direction during the actual operation of the hoisting motor.

[0060] Preferably, the lifting mechanism descends at a constant speed at the rated frequency of the lifting motor, including the process of acceleration and deceleration, that is, accelerating from 0 speed to the rated frequency, running at a constant speed at the rated frequency, and then decelerating from the rated frequency to 0 speed.

[0061] Measure the second swing period of the weight at the stop position, and obtain the second equivalent pendulum length based on the second swing period;

[0062] Preferably, the second swing period of the heavy object in the direction of the trolley's movement at the upper limit position is measured, and the specific measurement method is the same as that for measuring the first swing period.

[0063] Preferably, the second swing cycle refers to the time taken for the weight to swing from the highest point on the left to the highest point on the right, and then back from the highest point on the right to the highest point on the left when it is at the stop position.

[0064] Preferably, the second swing period is measured five times with a stopwatch and the average value is taken as the final second swing period T2, which makes the measurement of the second swing period more accurate.

[0065] Preferably, the formula for calculating the second equivalent pendulum length L2 is: g represents the acceleration due to gravity, with a value of 9.8, and π represents pi, with a value of 3.14.

[0066] Preferably, the second equivalent pendulum length L2 is greater than the first equivalent pendulum length L1. The longer the distance between the weight and the hoisting drum, the longer the swing period and the longer the equivalent pendulum length.

[0067] Real-time calculations during normal operation of the hoisting mechanism:

[0068] The rate of change of the equivalent pendulum length is obtained based on the real-time speed of the descent, the first equivalent pendulum length, the position deviation value, and the second equivalent pendulum length.

[0069] Preferably, the calibration data L1, L2 and H are input into the corresponding parameters of the lifting frequency converter, and the real-time calculation function of the equivalent pendulum length is enabled.

[0070] Preferably, after the real-time calculation function of the equivalent pendulum length is enabled, the change rate v1 of the equivalent pendulum length is calculated based on the real-time speed v of the descent action of the lifting mechanism.

[0071] Preferably, during the lifting mechanism's ascent or descent, the equivalent pendulum length changes in real time, and the rate of change of the equivalent pendulum length is proportional to the lifting mechanism's ascent or descent speed. The lifting mechanism's ascent or descent speed is controlled by the lifting frequency converter, which controls the lifting motor's real-time operating frequency f. cmd Decide.

[0072] Preferably, the real-time descent speed v is synchronized with the real-time operating frequency f of the hoisting motor controlled by the hoisting inverter. cmd They are directly proportional, and the conversion formula is as follows:

[0073]

[0074] Among them, F norm This indicates the rated frequency of the hoisting motor; this value can be found on the hoisting motor's nameplate. norm This indicates the lifting speed of the crane's hoisting mechanism corresponding to the rated frequency of the hoisting motor. This value can be found on the crane's nameplate. cmd This indicates the real-time operating frequency of the hoisting motor controlled by the hoisting inverter, f. cmd This is a variable, and its value can be obtained through the lifting frequency converter.

[0075] Preferably, during the lifting mechanism's ascent or descent, the equivalent pendulum length in the trolley's running direction changes in real time. The rate of change of the equivalent pendulum length is proportional to the lifting mechanism's ascent or descent speed, which is controlled by the lifting frequency converter at the lifting motor's real-time operating frequency f. cmd Decide.

[0076] Preferably, the formula for calculating the equivalent pendulum length change rate v1 is as follows:

[0077]

[0078] The real-time equivalent pendulum length of the weight is obtained based on the rate of change of the equivalent pendulum length v1.

[0079] Preferably, based on the first equivalent pendulum length L1 and the equivalent pendulum length change rate v1, the real-time equivalent pendulum length L of the load moving in the direction of the trolley is calculated in real time during the lifting or lowering process of the hoisting mechanism. s .

[0080] Preferably, the real-time equivalent pendulum length L s The calculation formula is as follows:

[0081]

[0082] Preferably, during the lifting mechanism's ascent, f cmd Take the negative value, and the real-time equivalent pendulum length L s It becomes smaller; during the descent of the lifting mechanism, f cmd Take a positive value, and calculate the real-time equivalent pendulum length L.s It gets bigger.

[0083] Preferably, when the lifting mechanism reaches the upper limit position, The integral value is cleared to 0, and after leaving the upper limit position, Begin integration calculation.

[0084] Preferably, the above-mentioned real-time equivalent pendulum length L is used. s The calculation formula can accurately calculate the equivalent pendulum length in the direction of the large vehicle's movement and the equivalent pendulum length in the direction of the small vehicle's movement in real time.

[0085] Preferably, determined by the structural form of the container gantry crane, the equivalent pendulum length in the direction of the main trolley travels is different from the equivalent pendulum length in the direction of the trolley travels for the same lifting height.

[0086] This invention discloses a method for detecting the equivalent pendulum length of a heavy object for anti-sway control. The method calculates the change rate of the equivalent pendulum length during the rise or fall of the crane's hoisting mechanism based on the real-time speed of the rise or fall, and then integrates the change rate to obtain the accurate real-time equivalent pendulum length. This invention does not require additional external sensors and can obtain the equivalent pendulum length of the heavy object when the crane is performing anti-sway control in the direction of the trolley or crane using the existing electronic control system of the crane. The operation process is simple and highly practical.

[0087] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0088] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for detecting the equivalent pendulum length of a heavy object for anti-sway control, characterized in that, include: Raise the lifting device with the load attached to the upper limit position of the hoisting mechanism; The hoisting motor is controlled to rotate forward by the hoisting frequency converter. The hoisting motor drives the reducer to rotate, and the reducer drives the hoisting drum to rotate. The hoisting drum drives the lifting device to rise through the wire rope. After receiving the upper limit position signal, the hoisting frequency converter controls the hoisting motor to stop. Measure the first swing period of the weight at the upper limit position, and obtain the first equivalent pendulum length based on the first swing period; The lifting device with the load is lowered to a stop position at a preset distance from the ground. The lifting motor is reversed by the lifting frequency converter. The lifting motor drives the reducer to rotate, and the reducer drives the lifting drum to rotate. The lifting drum lowers the lifting device through the wire rope until it reaches the stop position at a preset distance from the ground. The real-time speed of the descent is obtained, and the position deviation value relative to the upper limit position is obtained based on the real-time speed of the descent. The position deviation value is used The calculation formula is as follows: ,in, This indicates the real-time speed of the descent. The real-time speed of the descent action The hoisting frequency converter controls the real-time operating frequency of the hoisting motor. They are directly proportional, and the conversion formula is as follows: ； in, This indicates the rated frequency of the hoisting motor. This indicates the lifting speed of the lifting mechanism corresponding to the rated frequency of the lifting motor. This indicates the real-time operating frequency of the hoisting motor controlled by the hoisting frequency converter; Measure the second swing period of the weight at the stop position, and obtain the second equivalent pendulum length based on the second swing period; The rate of change of the equivalent pendulum length is obtained based on the real-time speed of the descent, the first equivalent pendulum length, the position deviation value, and the second equivalent pendulum length. The real-time equivalent pendulum length of the weight is obtained based on the rate of change of the equivalent pendulum length.

2. The method for detecting the equivalent pendulum length of a heavy object for anti-sway control according to claim 1, characterized in that, The rate of change of the equivalent pendulum length The calculation formula is as follows: ,in, Indicates the first equivalent pendulum length. This indicates the second equivalent pendulum length.

3. The method for detecting the equivalent pendulum length of a heavy object for anti-sway control according to claim 2, characterized in that, The first equivalent pendulum length is obtained based on the first swing period, and the second equivalent pendulum length is obtained based on the second swing period, specifically including: The formula for calculating the equivalent pendulum length based on the swing period is: , =1,2; in Indicates the first Equivalent pendulum length Indicates the first Swing cycle, This represents the acceleration due to gravity, with a value of 9.

8. This represents pi, with a value of 3.

14.

4. The method for detecting the equivalent pendulum length of a heavy object for anti-sway control according to claim 3, characterized in that, The first swing cycle and the second swing cycle refer to the time taken for the weight to swing from the highest point on the left to the highest point on the right, and then back from the highest point on the right to the highest point on the left, when the weight is in different positions.

5. The method for detecting the equivalent pendulum length of a heavy object for anti-sway control according to claim 3, characterized in that, The real-time equivalent pendulum length is used The calculation formula is as follows: 。 6. The method for detecting the equivalent pendulum length of a heavy object for anti-sway control according to claim 5, characterized in that, The lifting mechanism rises. Take the negative value, and calculate the equivalent pendulum length in real time. The size decreases; the lifting mechanism descends. Take a positive value, and calculate the equivalent pendulum length in real time. It gets bigger.

Images