Floating crane control system and control method for evading wave resonance zones

Abstract

The application discloses a floating crane control system and control method for avoiding wave resonance area, comprising: a measuring unit, including a ship attitude measuring device, for measuring the motion trajectory data of the ship body; a crane amplitude angle measuring device, for measuring the luffing angle data of the crane boom; a steel wire rope length measuring device, for measuring the rope length data of the hoisting steel wire rope; an executing unit, for adjusting the luffing angle of the crane boom and the wire length of the hoisting steel wire rope; and a control unit, including a controller, electrically connected with the measuring unit and the executing unit respectively. The application realizes the measurement of the driving period of wave excitation and the resonance period of the hoisted object through the devices of the measuring unit, cooperates with the control unit and the executing unit to control the steel wire rope length and the boom amplitude angle, and makes the hoisted object avoid the current wave resonance area during normal operation of the crane, effectively suppresses the swing of the hoisted object in space, and improves the hoisting construction efficiency on the basis of ensuring construction safety.

Description

Technical Field

[0001] This invention relates to the field of crane technology. More specifically, this invention relates to a control system and method for a floating crane that avoids wave resonance zones. Background Technology

[0002] With the development of technology, human engineering construction has gradually moved to the ocean, significantly increasing the difficulty compared to land-based construction. When ships are in calm seas, traditional floating cranes can complete normal operations. However, in rough seas, the waves cause changes in the ship's attitude, making the load on the floating crane prone to swaying. This greatly increases the operational difficulty of floating cranes and also raises the risk of accidents. How to prevent the load on a floating crane from swaying under wave excitation is a pressing problem that modern marine engineering construction equipment needs to overcome.

[0003] There are two main traditional methods to suppress the swaying of loads on floating cranes. The first is mechanical sway suppression, which mainly involves adding mechanical structures to the outside of the crane to suppress swaying. This method requires modification of the original crane structure, resulting in a complex structure, increased maintenance difficulty, and a certain impact on the crane's operating range. The second is electronic sway suppression, which achieves the purpose of suppressing the swaying of loads by controlling the crane's rotation, lifting, and luffing. This method prevents the crane from performing normal construction operations during the swaying suppression period, reducing work efficiency and increasing time costs.

[0004] To address the aforementioned issues, it is necessary to design a floating crane control system and method that avoids wave resonance zones, effectively suppressing the swaying of the crane's load while ensuring construction safety and efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a floating crane control system and method for avoiding wave resonance zones. By using a ship attitude measuring device to measure the driving cycle of real-time wave excitation, and coordinating with a crane amplitude measuring device, a wire rope length measuring device, a control unit, and an execution unit to control the wire rope length and boom amplitude, the suspended load avoids the current wave resonance zone during normal crane operation, effectively suppressing the swing of the suspended load in space, and improving lifting efficiency while ensuring construction safety.

[0006] To achieve these objectives and other advantages according to the present invention, a floating crane control system for avoiding wave resonance zones is provided, comprising:

[0007] The measurement unit includes a ship attitude measuring device configured to measure the motion trajectory data of the ship carrying the crane; a crane boom angle measuring device configured to measure the luffing angle data of the crane boom; and a wire rope length measuring device configured to measure the length data of the lifting wire rope.

[0008] The execution unit includes two sets of servo motors, which are respectively configured to adjust the luffing angle of the crane boom and the outgoing length of the hoisting wire rope;

[0009] A control unit, comprising a controller electrically connected to the measuring unit and the execution unit, respectively;

[0010] The controller receives motion trajectory data, amplitude angle data, and rope length data transmitted by the measurement unit, and sends corresponding control commands to the execution unit based on the judgment result of whether the ship attitude change cycle falls within the yaw control range obtained from the analysis.

[0011] Preferably, the floating crane control system for avoiding wave resonance zones further includes a human-machine interface unit, which includes:

[0012] A display, electrically connected to the controller, is used to display the detection data of the measurement unit, the calculation data of the control unit, and the control parameters of the execution unit; an input panel, electrically connected to the display and the controller respectively, is used to adjust the control parameters of the execution unit.

[0013] Preferably, in the floating crane control system for avoiding wave resonance zones, the ship attitude measurement device includes an attitude measuring instrument mounted on the hull, and the data measured by the attitude measuring instrument includes the hull's roll angle and pitch angle.

[0014] Preferably, in the floating crane control system that avoids wave resonance zones, the crane amplitude measuring device includes an angle encoder, which is installed on the motor shaft at the tail of the crane boom. The data measured by the angle encoder includes the relative amplitude angle between the boom and the horizontal plane.

[0015] Preferably, in the floating crane control system that avoids wave resonance zones, the wire rope length measuring device includes a displacement encoder, which is installed on the rotating shaft of the crane drum, and the data measured by the displacement encoder includes the outgoing length of the hoisting wire rope.

[0016] Preferably, the floating crane control system for avoiding wave resonance zones includes a controller comprising: a data acquisition module configured to receive motion trajectory data, amplitude angle data, and rope length data from the measurement unit; a calculation module configured to analyze the ship's attitude change cycle based on the motion trajectory data and calculate the sway control range based on the amplitude angle data and the rope length data; a comparison module configured to compare the ship's attitude change cycle with the sway control range and output a judgment result indicating whether the ship's attitude change cycle falls within the sway control range; and a control module configured to receive the judgment result from the comparison module and send control commands to the execution unit based on this result.

[0017] The present invention also provides a method for controlling a floating crane to avoid wave resonance zones, comprising:

[0018] S1. The measurement unit collects the motion trajectory data of the ship, the luffing angle data of the crane boom, and the length data of the hoisting wire rope in real time and transmits them to the control unit.

[0019] S2. The control unit predicts the ship attitude change cycle at the current moment based on the ship's motion trajectory data within a set time, and calculates the resonant cycle of the suspended object at the current moment based on the real-time rope length data.

[0020] S3. Set the sway control range based on the resonance cycle of the suspended object and the actual operating conditions.

[0021] S4. The control unit compares the predicted ship attitude change cycle with the set sway control range. When the ship attitude change cycle falls within the sway control range, it determines that the load is not in the resonance zone and continues the operation. When the ship attitude change cycle falls outside the sway control range, it determines that the load is in the resonance zone. The control unit sends a control command to the execution unit to adjust the boom angle of the crane and the length of the wire rope, so that the load leaves the resonance zone and the operation continues.

[0022] S5. Repeat steps S1-S4 as the operation continues until the current operation ends, at which point control stops.

[0023] Preferably, in the floating crane control method for avoiding wave resonance zones, in step S3, the method for setting the sway control range is as follows:

[0024] When the crane is in the slewing phase, the sway control range is: T t >1.2T A ;

[0025] When the crane is in the lifting or lowering phase, the sway control range is: at t r ≤3T t Internally satisfying Tt >1.2T A ;

[0026] Among them, T t The current ship attitude change period;

[0027] T A The current moment represents the resonance period of the suspended object. s is the length of the hoisting wire rope at the current moment, and g is the acceleration due to gravity;

[0028] t r This represents the duration of the task starting from the current moment.

[0029] The present invention has at least the following beneficial effects:

[0030] This invention employs a control system and method for a floating crane that avoids wave resonance zones. It measures the driving cycle of real-time wave excitation using a ship attitude measurement device. This, combined with a crane amplitude measurement device, a wire rope length measurement device, a control unit, and an execution unit, collaboratively controls the wire rope length and boom amplitude to ensure the suspended load avoids the current wave resonance zone during normal crane operation, effectively suppressing the load's swaying in space. The control system of this invention has a simple structure and a clear and explicit control method. It does not require altering the mechanical structure of the floating crane, nor does it suspend normal crane operations while maintaining the sway suppression effect. It improves lifting efficiency while ensuring construction safety and is widely applicable to floating cranes in various harsh environmental conditions, showing promising application prospects.

[0031] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0032] Figure 1 This is a structural block diagram of a floating crane control system for avoiding wave resonance zones according to an embodiment of the present invention;

[0033] Figure 2 This is a structural diagram of the floating crane control system for avoiding wave resonance zones as described in the above embodiments;

[0034] Figure 3 This is a flowchart of the floating crane control method for avoiding wave resonance zones described in the above embodiments;

[0035] Figure 4 The diagram above shows the mechanical structure analysis of the crane and the load in the above embodiments.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Wire rope length measuring device; 2. Crane amplitude measuring device; 3. Ship attitude measuring device. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0039] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified. In the description of this invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] like Figure 1-4 As shown, the present invention provides a floating crane control system for avoiding wave resonance zones, comprising:

[0041] The measurement unit includes a ship attitude measuring device 3, which is configured to measure the motion trajectory data of the ship carrying the crane; a crane boom angle measuring device 2, which is configured to measure the boom angle data of the crane; and a wire rope length measuring device 1, which is configured to measure the length data of the hoisting wire rope.

[0042] The execution unit includes two sets of servo motors, which are respectively configured to adjust the luffing angle of the crane boom and the outgoing length of the hoisting wire rope;

[0043] A control unit, comprising a controller electrically connected to the measuring unit and the execution unit, respectively;

[0044] The controller receives motion trajectory data, amplitude angle data, and rope length data transmitted by the measurement unit, and sends corresponding control commands to the execution unit based on the judgment result of whether the ship attitude change cycle falls within the yaw control range obtained from the analysis.

[0045] In the above technical solution, the ship attitude measurement device is used to acquire ship attitude change data (i.e., the motion trajectory of the ship), the crane luffing angle measurement device is used to acquire the luffing angle data of the floating crane boom, and the wire rope length measurement device is used to acquire the length data of the hoisting wire rope. Thus, the overall measurement unit can realize the detection of the working and motion status of the ship and its floating crane during operation. The control unit is equipped with a main control program (MSP) for processing the aforementioned measurement data. Specifically, this includes analyzing the ship's motion trajectory (obtaining the ship's attitude change cycle, i.e., the driving cycle of real-time wave excitation) and determining the sway control range. The resonance cycle of the suspended load can be calculated using the length data of the hoisting wire rope. The remaining working time and working status at each moment can be calculated (predicted) using the set crane operating parameters (hoisting height, wire rope winding speed, rotation angle, rotation speed, etc.) and the crane boom's luffing angle data (at the current moment). Combining the resonance cycle of the suspended load and the crane's real-time operating status, the resonance influence range of wave excitation on the suspended load can be accurately determined. The range within which the suspended load is not affected by wave excitation is the sway control range. Simultaneously, the control unit also includes a crane luffing angle control program and a wire rope length control program, used to output corresponding control commands to the outside based on the judgment result of whether the ship's attitude change cycle falls within the sway control range (whether the suspended load will be excited by waves). The execution unit is used to adjust the luffing angle of the crane boom and the lead length of the hoisting wire rope according to the control commands. The execution unit has two sets of servo motors, including a luffing motor and a hoisting motor. The luffing motor is installed at the tail of the crane boom (the crane boom can be configured as a multi-section boom connected end to end, with multiple luffing motors corresponding to it), and adjusts the relative rotation angle of the crane boom with respect to the horizontal plane. The hoisting motor is located at the crane drum used for winding and unwinding the hoisting wire rope, and is used to control the raising or lowering of the load (hoisting wire rope). When the control unit determines that the load will be excited by waves in the current state (the ship's attitude change cycle falls outside the sway control range), the execution unit adjusts and controls the luffing angle of the crane boom and the length of the hoisting wire rope through the luffing motor and hoisting motor respectively, according to the control command, so that the ship's attitude change cycle can fall within the sway control range, that is, the load will not be affected by the resonance of wave excitation.In the above control process, since the changes in ship attitude are mainly caused by the excitation of external waves, that is, under relatively fixed external conditions, the ship attitude change cycle is also relatively fixed and is not affected by the lifting operation (the working parameters of the crane). Therefore, when the ship attitude change cycle obtained from the analysis falls outside the set sway control range, the size of the sway control range itself can be changed by adjusting the influence parameters of the sway control range (the luffing angle of the crane boom, the length of the lifting wire rope, etc.) to adapt it to the ship attitude change cycle at the current moment. This allows the hoisted object to avoid the wave resonance zone during the lifting operation, and while not affecting the progress of the lifting operation (by adjusting the working parameters), the swaying of the hoisted object in space is minimized as much as possible, thereby further improving construction safety while ensuring work efficiency.

[0046] This invention uses a ship attitude measurement device to measure the driving cycle of real-time wave excitation. Combined with a crane amplitude measurement device, a wire rope length measurement device, a control unit, and an execution unit, it coordinates the control of the wire rope length and boom amplitude to ensure that the suspended load avoids the current wave resonance zone during normal crane operation, effectively suppressing the swaying of the load in space. The control system of this invention has a simple structure and a clear and explicit control method. It does not require changes to the mechanical structure of the floating crane, nor does it require suspending normal crane operations while maintaining the sway suppression effect. It improves lifting efficiency while ensuring construction safety and is widely applicable to floating cranes in various harsh environmental conditions, showing promising application prospects.

[0047] In another technical solution, the floating crane control system for avoiding wave resonance zones further includes a human-machine interface unit, which comprises:

[0048] A display, electrically connected to the controller, is used to display the detection data of the measurement unit, the calculation data of the control unit, and the control parameters of the execution unit; an input panel, electrically connected to the display and the controller respectively, is used to adjust the control parameters of the execution unit.

[0049] The human-machine interface unit is used for displaying various detection data and process data (predictive and calculated data) and setting control parameters. In this embodiment, the human-machine interface unit can be a touch screen display. The screen can display the ship's motion trajectory data (ship attitude change cycle), the crane boom's luffing angle data, the lifting wire rope length data, and various crane control parameters (including but not limited to the control parameters of the execution unit). It can also serve as an input panel for real-time setting and adjustment of the crane's control parameters. Specifically, the control parameters include the maximum and minimum values ​​of the crane boom's luffing angle and the maximum and minimum values ​​of the lifting wire rope length.

[0050] In another technical solution, the floating crane control system for avoiding wave resonance zones includes a ship attitude measurement device comprising an attitude measuring instrument mounted on the hull. The attitude measuring instrument measures the ship's roll and pitch angles. In this embodiment, the attitude measuring instrument can utilize existing attitude sensors, primarily collecting roll and pitch angle data at a frequency of 0.5 Hz and an accuracy of ±0.1 degrees. The attitude sensor transmits data via its built-in serial port. Specifically, the attitude measuring instrument measures the physical information of the carrier (ship), such as angular velocity, tilt angle, and acceleration, and then performs professional calculations to obtain its motion trajectory. Changes in ship attitude are caused by external wave excitation. By analyzing the trajectory change pattern using the attitude measuring instrument, the ship attitude transformation cycle (the time it takes for the ship's trajectory to return to the same position under the cyclical pattern) under wave excitation can be predicted, i.e., the real-time wave excitation drive cycle.

[0051] In another technical solution, the floating crane control system for avoiding wave resonance zones includes an angle encoder as the crane's amplitude measurement device. This encoder is mounted on the motor shaft at the tail of the crane's boom. The data measured by the angle encoder includes the relative amplitude angle between the boom and the horizontal plane. In this embodiment, the angle encoder's acquisition frequency is 0.5Hz, and data is transmitted via its built-in serial port. Here, the amplitude angle data acquired by the angle encoder represents the change in the angle between the crane boom and the horizontal plane, primarily considering the additional impact of the boom's amplitude angle related to the lifting (height change) of the load.

[0052] In another technical solution, the floating crane control system for avoiding wave resonance zones includes a wire rope length measuring device comprising a displacement encoder mounted on the rotating shaft of the crane drum. The displacement encoder measures the length of the hoisting wire rope as it extends. In this embodiment, the displacement encoder uses a sampling frequency of 0.5Hz and transmits data via its built-in serial port. The displacement encoder records the winding and unwinding lengths of the wire rope at the crane drum, thereby calculating the real-time hoisting length of the wire rope in the vertical direction.

[0053] In another technical solution, the floating crane control system for avoiding wave resonance zones includes a controller comprising: a data acquisition module configured to receive motion trajectory data, amplitude angle data, and rope length data from the measurement unit; a calculation module configured to analyze the ship's attitude change cycle based on the motion trajectory data and calculate the sway control range based on the amplitude angle data and the rope length data; a comparison module configured to compare the ship's attitude change cycle with the sway control range and output a judgment result indicating whether the ship's attitude change cycle falls within the sway control range; and a control module configured to receive the judgment result from the comparison module and send control commands to the execution unit based on this result. The controller utilizes multiple internal modules to transmit and analyze data and generate control commands based on the analysis results. In this embodiment, the control unit can be a computer or a PLC. After receiving real-time data from the measurement unit, the control unit analyzes and calculates this data, compares the predicted ship attitude change period with the set sway control range, derives corresponding control commands, and transmits them to the execution unit to control the crane's working parameters (the length of the lifting wire rope, the boom luffing angle, etc.). The control strategy of the control commands is to ensure that the ship attitude change period falls within the sway control range. In addition to the servo motors controlling the boom luffing angle and the length of the lifting wire rope, the execution unit also includes other devices that control the crane's operation, such as a slewing motor controlling the boom's in-situ rotation and a speed reduction mechanism controlling the speed of each motor in the crane system. The controller in the control unit integrates the control of each device (motor, speed reduction mechanism, etc.) in the execution unit, thereby enabling real-time and effective control of the crane's working parameters. It also provides real-time guidance and adjustment of the lifting operation parameters based on the measurement data fed back by the measurement unit, which helps to further improve work efficiency while ensuring construction safety.

[0054] The present invention also provides a method for controlling a floating crane to avoid wave resonance zones, comprising:

[0055] S1. The measurement unit collects the motion trajectory data of the ship, the luffing angle data of the crane boom, and the length data of the hoisting wire rope in real time and transmits them to the control unit.

[0056] S2. The control unit predicts the ship attitude change cycle at the current moment based on the ship's motion trajectory data within a set time, and calculates the resonant cycle of the suspended object at the current moment based on the real-time rope length data.

[0057] S3. Set the sway control range based on the resonance cycle of the suspended object and the actual operating conditions.

[0058] S4. The control unit compares the predicted ship attitude change cycle with the set sway control range. When the ship attitude change cycle falls within the sway control range, it determines that the load is not in the resonance zone (will not be excited by waves) and continues the operation. When the ship attitude change cycle falls outside the sway control range, it determines that the load is in the resonance zone (will be excited by waves). The control unit sends control commands to the execution unit to adjust the boom angle of the crane and the length of the wire rope, so that the load leaves the resonance zone and continues normal operation.

[0059] S5. Repeat steps S1-S4 as the operation continues until the current operation ends, at which point control stops.

[0060] In the above technical solution, the change in ship attitude is caused by the excitation of external waves. In a fixed sea area over a certain period of time, the excitation period of the waves on the ship remains essentially constant. Based on this, the average period of multiple ship attitude change cycles prior to the current moment can be used as the ship attitude change cycle value at the current moment, i.e.: In the formula, T t Let T be the period of the ship's attitude change at time t. t-i Let be the ti-th ship attitude change cycle (the ship attitude change cycle at time ti), i = 1, 2, ..., n; in this embodiment, the calculation is performed using the first 10 ship attitude change cycles before the current time, i.e., i is set to 10. The mathematical model of a floating crane lifting a load can be approximated as a simple pendulum model, with its natural period being: In the formula, T A s is the natural period of the suspended load's motion (i.e., the resonance period of the suspended object), s is the length of the hoisting wire rope, and g is the acceleration due to gravity.

[0061] Therefore, it can be seen that the natural period of the suspended object's motion (the object's resonance period) can be changed by adjusting the length of the hoisting wire rope. When the control unit in S4 determines that the ship's attitude change period falls outside the sway control range, the object's resonance period (sway control range) can be changed by altering the length of the hoisting wire rope (i.e., controlling the servo motor of the execution unit to extend and retract the hoisting wire rope). This allows the relatively fixed (affected by external wave excitation) ship attitude change period to fall within the sway control range, thus avoiding the impact of wave excitation on the object's resonance. Simultaneously, since adjusting only the length of the hoisting wire rope will cause a change in the object's lifting height, when maintaining a constant object height during hoisting operations, a mechanical analysis of the crane and the object is necessary. Figure 4 As shown, in the XYZ coordinate system, point O represents the ship carrying the crane, line segment L represents the crane boom, line segment S represents the lifting wire rope, and point A represents the load, with its ordinate being Z. APoint P represents the lifting point at the boom tip of the crane, with its ordinate being Z. P Through geometric relationships, we can obtain: Z P =lsinθ, where l is the boom length of the crane, and θ is the boom angle (relative to the horizontal plane); then the ordinate of the suspended object A is Z. A It can be represented as Z A =lsinθ-s, where s is the length of the lifting wire rope. Therefore, by coordinating the luffing angle of the crane boom and the length of the lifting wire rope, the height of the suspended object in space can be kept constant. The length of the lifting wire rope is adjusted according to the required sway control range (ensuring the ship's attitude change cycle falls within the sway control range), while the luffing angle of the crane boom is adaptively adjusted according to the change in the length of the lifting wire rope. Thus, during crane lifting operations, the control system can, through coordinated control of the crane boom's luffing angle and the lifting wire rope length, ensure that the suspended object does not sway due to wave excitation in space, while also meeting the operational requirements of the crane lifting operation.

[0062] In another technical solution, in the floating crane control method for avoiding wave resonance zones, S3, the method for setting the sway control range is as follows:

[0063] When the crane is in the slewing phase, the sway control range is: T t >1.2T A ;

[0064] When the crane is in the lifting or lowering phase, the sway control range is: at t r ≤3T t Internally satisfying T t >1.2T A ;

[0065] Among them, T t The current ship attitude change period;

[0066] T A The current moment represents the resonance period of the suspended object. s is the length of the hoisting wire rope at the current moment, and g is the acceleration due to gravity;

[0067] t r This represents the duration of the task starting from the current moment.

[0068] In the above technical solution, a complete lifting operation of the crane can be divided into a hoisting stage, a slewing stage, and a lowering stage. Through multiple experiments and summarizing the resonance law, it can be seen that when T... t >1.2T AWhen the above conditions are met (the foundation sway control range), the suspended object will not be excited by the waves (not in the resonance zone) regardless of the stage of the hoisting operation (slewing, lifting, or lowering).

[0069] During the slewing phase of the hoisting operation, the crane boom rotates in place while the load is moved horizontally at the same height. The length of the hoisting wire rope remains unchanged during this process, i.e., T. A Since it remains unchanged, the sway control range is also relatively fixed at this time, satisfying T. t >1.2T A The crane boom's luffing angle, the crane's slewing angle, or the ship's position can be freely adjusted according to the operation, without causing resonance or swaying of the load.

[0070] During the lifting or lowering phase of a hoisting operation, the length of the hoisting wire rope is constantly changing due to its extension and retraction. This means the resonance period of the suspended load also varies over time. Therefore, there are periods during which the foundation's sway control range (T) is met. t >1.2T A However, during certain working periods, the basic sway control range is not met. According to experimental data, from T... t ≤1.2T A Starting from the moment when the basic oscillation control range is not met, within the first 3 wave cycles (i.e., t... r ≤3T t At the beginning of the wave, the swing amplitude of the load is very small (negligible). As the wave cycle (ship attitude change cycle) accumulates, the swing amplitude of the load gradually increases. After 7 wave cycles, the load can be excited to swing to 20 degrees, meaning that at this point, the load will swing significantly under the drive of wave excitation. Therefore, it can be concluded that during the lifting or lowering of the load, if the total duration during which it does not meet the basic sway control range is less than or equal to 3 wave cycles (i.e., it can reach the state that meets the basic sway control range or end the operation within 3 ship attitude change cycles), the lifting operation of the load can still be considered unaffected by wave excitation.

[0071] The above-mentioned sway control range is illustrated using a floating crane in a practical application as an example:

[0072] Specifically, when the ship is in a medium-to-long-cycle wave environment, the average wave period (ship attitude change period) at the current moment, predicted by the measurement unit and control unit, is about 11.2 seconds. The boom of the floating crane is 50 meters long, and the allowable range of the boom's luffing angle during lifting operations is 30-60 degrees. Under full load, the lifting speed (lifting speed of the load) can reach 23 m / min.

[0073] Therefore, to meet the basic sway control range, through T t >1.2T A It can be determined that the length of the lifting wire rope needs to be less than 21.65 meters. A complete crane operation can be divided into three stages: the hoisting stage (lifting the load from its original position to a set height), the slewing stage (moving the load horizontally to directly above the set position), and the descent stage (lowering the load from the set height to the set position). During the slewing stage, provided the lifting wire rope length is less than 21.65 meters, the crane's boom angle, slewing angle, or the ship's position can be freely adjusted according to the operational situation without causing resonance swaying of the load due to wave excitation. During the hoisting stage, assuming the crane boom's boom angle is 30 degrees and the initial length of the vertical section of the lifting wire rope is 25 meters, lifting the load at a speed of 23 m / min (with the lifting wire rope length gradually decreasing), calculations show that the lifting wire rope length will be less than 21.65 meters after 8.7 seconds, thus satisfying T. t >1.2T A , and at this time t r It was 8.7 seconds, T t It is 11.2 seconds, or t r =0.78T t <3T t The sway control is within the set range, so the suspended load will not sway. During the descent phase, the boom angle is set to 30 degrees, the lifting height to 25m, and the initial length of the vertical section of the lifting wire rope is 0 meters. The load is lowered at a speed of 23m / min (the length of the lifting wire rope gradually increases). Calculations show that the time from the start of descent to the load landing is only 8.7 seconds, which does not meet the requirement that the length of the lifting wire rope be less than 21.65 meters. Therefore, at this point, t... r It was 8.7 seconds, T t It lasted 11.2 seconds, t r =0.78T t <3T t It meets the set sway control range, so the suspended object will basically not sway.

[0074] Therefore, based on the set sway control range, during the aforementioned rising or falling phases, it is only necessary to ensure that T remains within 3 wave cycles. t >1.2TA Under the condition that the length of the hoisting wire rope is less than 21.65 meters, other working parameters of the crane (amplitude angle of the crane boom, slewing angle, ship position, etc.) can be adjusted at will without causing resonance swaying of the hoisted object due to wave excitation.

[0075] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A floating crane control system for avoiding wave resonance zones, characterized in that, include: The measurement unit includes a ship attitude measurement device configured to measure the motion trajectory data of the hull carrying the crane; A crane boom angle measuring device is configured to measure the boom angle data of a crane; a wire rope length measuring device is configured to measure the length data of a hoisting wire rope. The execution unit includes two sets of servo motors, which are respectively configured to adjust the luffing angle of the crane boom and the outgoing length of the hoisting wire rope; The control unit includes a controller, which is electrically connected to the measuring unit and the execution unit respectively. The controller includes a data acquisition module, which is configured to receive motion trajectory data, amplitude angle data and rope length data from the measuring unit. The calculation module is configured to analyze the ship's attitude change cycle based on the motion trajectory data, and calculate the sway control range based on the amplitude angle data and the rope length data; the comparison module is configured to compare the ship's attitude change cycle with the sway control range, and output a judgment result indicating whether the ship's attitude change cycle falls within the sway control range; the control module is configured to receive the judgment result from the comparison module and send control commands to the execution unit based on this result. The controller receives motion trajectory data, amplitude angle data, and rope length data transmitted by the measurement unit, and sends corresponding control commands to the execution unit based on the judgment result of whether the ship's attitude change cycle falls within the sway control range. When the ship's attitude change cycle falls outside the sway control range, the resonance cycle of the hoisted object is changed by changing the length of the hoisting wire rope, so that the ship's attitude change cycle falls within the sway control range. The controller also coordinates the adjustment of the amplitude angle of the crane boom and the length of the hoisting wire rope to keep the height of the hoisted object in space constant.

2. The floating crane control system for avoiding wave resonance zones as described in claim 1, characterized in that, It also includes a human-computer interaction unit, which includes: A display, electrically connected to the controller, is used to display the detection data of the measurement unit, the calculation data of the control unit, and the control parameters of the execution unit; an input panel, electrically connected to the display and the controller respectively, is used to adjust the control parameters of the execution unit.

3. The floating crane control system for avoiding wave resonance zones as described in claim 1, characterized in that, The ship attitude measurement device includes an attitude measuring instrument, which is installed on the hull. The data measured by the attitude measuring instrument includes the roll angle and pitch angle of the hull.

4. The floating crane control system for avoiding wave resonance zones as described in claim 1, characterized in that, The crane amplitude measuring device includes an angle encoder, which is installed on the motor shaft at the tail of the crane boom. The data measured by the angle encoder includes the relative amplitude angle between the boom and the horizontal plane.

5. The floating crane control system for avoiding wave resonance zones as described in claim 1, characterized in that, The wire rope length measuring device includes a displacement encoder, which is installed on the rotating shaft of the crane drum. The data measured by the displacement encoder includes the outgoing length of the hoisting wire rope.

6. A control method for a floating crane that avoids wave resonance zones, characterized in that, include: S1. The measurement unit collects the motion trajectory data of the ship, the luffing angle data of the crane boom, and the length data of the hoisting wire rope in real time and transmits them to the control unit. S2. The control unit predicts the ship attitude change cycle at the current moment based on the ship's motion trajectory data within a set time, and calculates the resonant cycle of the suspended object at the current moment based on the real-time rope length data. S3. Set the sway control range based on the resonance cycle of the suspended object and the actual operating conditions. S4. The control unit compares the predicted ship attitude change cycle with the set sway control range. When the ship attitude change cycle falls within the sway control range, it determines that the load is not in the resonance zone and continues the operation. When the ship attitude change cycle falls outside the sway control range, it determines that the load is in the resonance zone. The control unit sends a control command to the execution unit to adjust the boom angle of the crane and the length of the wire rope, so that the load leaves the resonance zone and the operation continues. S5. Repeat steps S1-S4 as the operation continues until the current operation ends, at which point control stops.

7. The floating crane control method for avoiding wave resonance zones as described in claim 6, characterized in that, In S3, the method for setting the sway control range is as follows: When the crane is in the slewing phase, the sway control range is: ; When the crane is in the lifting or lowering phase, the sway control range is: Internal satisfaction ; Among them, T t The current ship attitude change period; T A The current moment represents the resonance period of the suspended object. s is the length of the hoisting wire rope at the current moment, and g is the acceleration due to gravity; t r This represents the duration of the task starting from the current moment.

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