Tower crane active anti-swing control method and system based on GPS positioning of a spreader

Abstract

The application discloses a tower crane active anti-swing control method and system based on GPS positioning of a lifting appliance, and the method comprises the following steps: acquiring the three-dimensional space position of the lifting appliance in real time through a GPS receiver; calculating the actual motion speed vector of the lifting appliance according to the lifting appliance positions at adjacent time points; acquiring the instruction speed vector of a tower crane motion mechanism, and calculating the deviation vector of the instruction speed vector and the actual motion speed vector; based on the speed deviation vector, combining the length of the lifting rope, and inversely deriving the current horizontal swing angle vector and swing angle speed vector of the lifting appliance; taking the swing angle vector and the swing angle speed vector as feedback, inputting the feedback into a nonlinear anti-swing controller, and generating a speed compensation instruction; superimposing the speed compensation instruction on the original instruction speed, and outputting the superimposed speed to a frequency converter to drive the motor to perform reverse compensation motion, so as to suppress the swing of the lifting appliance. The application combines nonlinear differential feed-forward-feedback compound control, realizes closed-loop compensation of a variable-frequency driving system, and significantly suppresses the load swing.

Description

Technical Field

[0001] This invention relates to the field of crane control technology, and more specifically to an active anti-sway control method and system for tower cranes based on GPS positioning of the lifting device. Background Technology

[0002] During the lifting, luffing, and slewing processes of a tower crane, the load is susceptible to swaying due to acceleration / deceleration impacts and external disturbances.

[0003] Existing methods for controlling the sway of tower cranes mainly include mechanical anti-sway and manual anti-sway. Mechanical anti-sway technologies, such as adding cross steel wire ropes or anti-sway frames, increase structural complexity, weight, and cost, and their effectiveness is limited. Manual anti-sway, on the other hand, relies on skilled operators to eliminate sway through inching operations, which is inefficient and unsustainable.

[0004] Some active anti-shake technologies typically rely on angle sensors or vision systems. Angle sensors are susceptible to vibration, temperature drift, and rain during long-term outdoor operation; vision systems are easily affected by light and dust, and have relatively high computational latency.

[0005] Therefore, there is an urgent need to develop an active anti-sway solution that does not require additional complex mechanical structures, has strong resistance to environmental interference, and can be seamlessly adapted to existing variable frequency drive systems. Summary of the Invention

[0006] In view of the above problems, the present invention is proposed to provide an active anti-sway control method and system for tower cranes based on GPS positioning of the lifting device to overcome or at least partially solve the above problems.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, embodiments of the present invention provide an active anti-sway control method for tower cranes based on GPS positioning of the lifting device, comprising the following steps: The three-dimensional spatial position of the lifting rig is obtained in real time by a GPS receiver installed on the rig; The actual velocity vector of the lifting device is calculated based on the position of the lifting device at adjacent moments; Obtain the commanded speed vector of the tower crane's motion mechanism, and calculate the deviation vector between the commanded speed vector and the actual motion speed vector; Based on the velocity deviation vector and the length of the lifting rope, the current horizontal swing angle vector and swing angular velocity vector of the lifting device are derived. The swing angle vector and swing angular velocity vector are used as feedback quantities and input to the nonlinear anti-sway controller to generate a speed compensation command. The speed compensation command is superimposed on the original command speed and output to the frequency converter to drive the motor to perform reverse compensation motion in order to suppress the sway of the lifting device.

[0009] Furthermore, in the step of acquiring the three-dimensional spatial position of the lifting rig in real time via a GPS receiver installed on the rig, the GPS receiver employs a differential GPS system, including: At least one GPS mobile station installed on top of the spreader, and a GPS base station installed on the tower crane's fixed foundation section or at a stable ground position; The GPS base station receives satellite signals and generates differential correction signals; the GPS rover receives satellite signals and the differential correction signals, and calculates the three-dimensional spatial position of the lifting device based on the differential correction signals.

[0010] Furthermore, the actual velocity vector of the spreader is calculated based on the position of the spreader at adjacent time points, specifically including: For each direction of motion of the spreader in the horizontal plane, a Kalman filter is constructed. The state of each Kalman filter includes the position p and velocity in that direction of motion. and acceleration a; Using the position in the direction of travel output by the GPS receiver as the observation value, and employing a uniform acceleration random walk model, the state transition matrix is ​​defined as follows: ; Define the process noise covariance matrix:

[0011] in The sampling period is q, and the spectral density of the accelerometer is q. Define observation matrix The observation noise variance R is taken as the square of the GPS horizontal positioning accuracy; Perform the following steps sequentially for each sampling time k: Prediction Steps , ; Update steps: , , ; From the updated state vector Extracting velocity components The actual velocity in that direction: in, This represents the position p and velocity in the direction of motion at time k before the update. The state vector consisting of acceleration a; This represents the updated state vector at time k; This represents the updated state vector at time k-1; The prior estimate is the error covariance; The posterior estimation error covariance is used to represent the uncertainty measure after the update at the previous time step; Indicates Kalman gain; Let k represent the observation at time k, and I represent the identity matrix; The velocity components in the two orthogonal directions are combined to form the actual velocity vector of the lifting device. .

[0012] Furthermore, the current horizontal swing angle vector and swing angular velocity vector of the spreader are obtained by using a velocity deviation-swing angle mapping model with a small angle approximation, as follows:

[0013] in, This represents the current horizontal swing angle vector of the spreader. The dimensionless coefficients were obtained through on-site calibration. Represents the velocity deviation vector Horizontal components, The sampling period is This refers to the length of the lifting rope.

[0014] Furthermore, in the step of inverting the current horizontal swing angle vector and swing angular velocity vector of the spreader, the swing angular velocity vector is obtained through the following formula:

[0015] in, This represents the current angular velocity vector of the spreader. The time interval between two adjacent sampling times, and when the change in the swing angle within Δt is less than the preset noise threshold. When the angle is 0.1°, the pendulum angular velocity vector is... Forced zeroing to prevent measurement noise amplification. The vector representing the horizontal swing angle at time t. The vector representing the horizontal swing angle at time t-1.

[0016] Furthermore, the nonlinear anti-sway controller is designed based on Lyapunov stability theory and adopts the following control law:

[0017] in, Indicates the speed compensation amount. This is a proportional feedback term used to provide the swing angle restoring torque; This is a differential feedback term used to provide oscillation damping; It is a nonlinear differential feedforward term, used to output reverse compensation in advance at the moment of acceleration and deceleration impact; , , These are the proportional gain coefficient, the differential gain coefficient, and the nonlinear differential feedforward coefficient, respectively. ; ; >0 represents the desired oscillation decay angular frequency; The damping ratio is in the range of 0.7. 1.0; makes the Lyapunov function The derivative of is greater than 0, and g is the acceleration due to gravity.

[0018] Furthermore, the controller also includes a gain adaptive scheduling module: which estimates the lifting weight in real time through feedback from the hoisting motor current. In conjunction with the real-time rope length L, it automatically adjusts according to a preset two-dimensional gain scheduling table. , , The possible values ​​of ; The adjustment rule for the gain scheduling table is to adjust the coefficients... , , Based on the set threshold, they are divided into three levels: large, medium, and small. when When the load is ≤ 0.3 times the rated load, the no-load gain group is used: Larger medium, Smaller; When 0.3 times the rated load < When the load is ≤ 0.8 times the rated load, the medium-load gain group should be used. medium, Larger medium; when When the load is greater than 0.8 times the rated load, the heavy-load gain group should be used. Smaller Larger Relatively large.

[0019] Furthermore, before inputting the swing angle vector and swing angular velocity vector as feedback quantities into the nonlinear anti-sway controller, the method further includes: a swing angle effectiveness determination step. Judge and compare the horizontal swing angle vector obtained by inversion Size relative to the preset threshold: when Then the horizontal swing angle vector The value is forcibly set to zero, and the nonlinear anti-sway controller does not trigger active compensation; when The nonlinear anti-sway controller then employs an incomplete control law. The speed compensation amount is obtained, where, Indicates the proportional gain coefficient; when The nonlinear anti-sway controller then employs a control law. The speed compensation amount is obtained; where, Indicates the speed compensation amount. This is a proportional feedback term used to provide the swing angle restoring torque; This is a differential feedback term used to provide oscillation damping; It is a nonlinear differential feedforward term, used to output reverse compensation in advance at the moment of acceleration and deceleration impact; , , These are the proportional gain coefficient, the differential gain coefficient, and the nonlinear differential feedforward coefficient, respectively. The minimum compensation threshold for the horizontal swing angle vector; The threshold for fully compensating for the horizontal swing angle vector.

[0020] Furthermore, the step of superimposing the speed compensation command onto the original command speed and outputting it to the frequency converter to drive the motor to perform reverse compensation motion also includes: Speed ​​compensation amount in speed compensation command Limit the amplitude: | | ≤ 0.3 · ,in This refers to the maximum operating speed of the corresponding mechanism; Speed ​​compensation after amplitude limiting The final speed is obtained by superimposing the original command speed. ; If the final speed >1.05 · This will trigger an overspeed warning and force the vehicle to stop. Attenuation of 50%; Continuously monitor the trend of the swing angle amplitude change. If the horizontal swing angle vector changes within three consecutive sampling periods... If the gain coefficient increases by more than 10% each time, the system is determined to be diverging. The gain coefficient of the nonlinear anti-sway controller is then reduced to 30% of the current value, and a fault alarm is issued.

[0021] In a second aspect, embodiments of the present invention also provide an active anti-sway control system for a tower crane according to any of the methods described in the first aspect, comprising: Sensing unit: at least one differential GPS mobile station mounted on the sling, and an optional six-axis IMU; Reference unit: A GPS reference station installed at a fixed location on the tower crane; Control unit: including industrial programmable controllers or embedded motion controllers that integrate Kalman filters, velocity deviation-swing angle observers, nonlinear anti-sway controllers, gain schedulers and safety logic modules; Actuation unit: includes frequency converters and motors that drive the luffing, slewing and hoisting mechanisms, and is connected to the control unit via real-time industrial Ethernet; Human-computer interaction unit: used to display real-time swing angle, compensation amount and alarm information.

[0022] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a method and system for active anti-sway control of tower cranes based on GPS positioning of the lifting device, which has the following beneficial effects: This invention eliminates the need for any mechanical anti-sway devices or precision angle sensors. Anti-sway control can be achieved using only a single or dual GPS unit (which can reuse existing construction base stations), significantly reducing hardware costs and maintenance difficulty. GPS signals are unaffected by dust, sunlight, or rain, offering higher reliability in harsh outdoor conditions compared to visual and infrared solutions.

[0023] This invention fundamentally solves the problems of signal delay and noise amplification by inverting through "velocity vector deviation" rather than "position difference". The nonlinear composite control balances steady-state de-swaying and dynamic excitation suppression.

[0024] The nonlinear anti-sway controller designed based on the Lyapunov method in this invention ensures the gradual stability of the system within the range of rope length and load variations. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a schematic diagram of the overall process of the method provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the installation of a differential GPS system provided in an embodiment of the present invention. Detailed Implementation

[0027] 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.

[0028] Before describing the present invention, let me briefly explain the working principle of the crane. The crane is a "tower crane". The crane is mainly composed of a hoisting mechanism, a luffing mechanism and a slewing mechanism. The three mechanisms are controlled by three frequency converters to control the corresponding motors to realize the up and down movement of the hook, the rotation of the crane boom and the forward and backward movement of the trolley on the boom.

[0029] This invention utilizes high-precision GPS to obtain the spatial position of the lifting device in real time, accurately estimates the swing angle and angular velocity through velocity vector deviation inversion, and combines nonlinear differential feedforward-feedback composite control to achieve closed-loop compensation for the variable frequency drive system, significantly suppressing load sway.

[0030] To address the issue of spreader swaying, this invention introduces the velocity vector deviation between the desired speed of the spreader and the actual GPS speed measurement. It then uses the length of the suspension rope to dynamically inversely deduce the sway angle state and designs a nonlinear control law based on Lyapunov stability theory.

[0031] To achieve the above objectives, the first aspect of this invention discloses an active anti-sway control method for tower cranes based on GPS positioning of the lifting device, referencing... Figure 1 This includes the following steps: The three-dimensional spatial position of the lifting rig is obtained in real time by a GPS receiver installed on the rig; The actual velocity vector of the lifting device is calculated based on the position of the lifting device at adjacent moments; Obtain the commanded speed vector of the tower crane's motion mechanism, and calculate the deviation vector between the commanded speed vector and the actual motion speed vector; Based on the velocity deviation vector and the length of the lifting rope, the current horizontal swing angle vector and swing angular velocity vector of the lifting device are derived. The swing angle vector and swing angular velocity vector are used as feedback quantities and input to the nonlinear anti-sway controller to generate a speed compensation command. The speed compensation command is superimposed on the original command speed and output to the frequency converter to drive the motor to perform reverse compensation motion in order to suppress the sway of the lifting device.

[0032] refer to Figure 2 In one specific embodiment, in the step of obtaining the three-dimensional spatial position of the lifting device, the GPS receiver adopts a differential GPS system. The differential GPS system includes: at least one GPS mobile station installed above the lifting device, and a GPS reference station installed at the fixed foundation section of the tower crane or at a stable ground position; the GPS reference station receives satellite signals and generates differential correction signals; the GPS mobile station receives the satellite signals and the differential correction signals, and calculates the three-dimensional spatial position of the lifting device based on the differential correction signals.

[0033] In a differential GPS system, the GPS base station receives satellite signals, calculates theoretical observations based on its known precise coordinates and satellite ephemeris, and generates a differential correction signal by combining actual measurements. The GPS rover receives the same satellite signals and acquires the differential correction signal sent by the GPS base station via a wireless link. It uses the differential correction signal to differentially correct its own observations, eliminating common errors in satellite clock bias, ephemeris errors, and atmospheric propagation delay. Based on the corrected observations, a double-difference carrier phase observation equation is established, integer ambiguity is fixed, and the baseline vector between the rover and the base station is calculated. The three-dimensional coordinates of the rover antenna phase center are calculated based on the known coordinates of the base station and the baseline vector.

[0034] In this invention, the actual velocity vector of the lifting device is calculated based on the position of the lifting device at adjacent moments, specifically including: For each direction of motion of the spreader in the horizontal plane, a Kalman filter is constructed. The state of each Kalman filter includes the position p and velocity in that direction of motion. and acceleration a; Using the position in the direction of travel output by the GPS receiver as the observation value, and employing a uniform acceleration random walk model, the state transition matrix is ​​defined as follows: ; Define the process noise covariance matrix:

[0035] in The sampling period is q, and the spectral density of the accelerometer is q. Define observation matrix The observation noise variance R is taken as the square of the GPS horizontal positioning accuracy; Perform the following steps sequentially for each sampling time k: Prediction Steps , ; Update steps: , , ; From the updated state vector Extracting velocity components The actual velocity in that direction: in, This represents the position p and velocity in the direction of motion at time k before the update. The state vector consisting of acceleration a; This represents the updated state vector at time k; This represents the updated state vector at time k-1; The prior estimate is the error covariance; The posterior estimation error covariance is used to represent the uncertainty measure after the update at the previous time step; Indicates Kalman gain; Let k represent the observation at time k, and I represent the identity matrix; The velocity components in the two orthogonal directions are combined to form the actual velocity vector of the lifting device. .

[0036] Then, the speed deviation vector is obtained from the actual speed vector of the lifting device and the commanded speed vector of the tower crane's motion mechanism.

[0037] After obtaining the velocity deviation vector, the horizontal swing angle vector and the swing angular velocity vector are obtained through inversion.

[0038] In one specific embodiment, the current horizontal swing angle vector of the spreader is obtained using a velocity deviation-swing angle mapping model with a small-angle approximation, as follows:

[0039] in, This represents the current horizontal swing angle vector of the spreader. The dimensionless coefficients were obtained through on-site calibration. Represents the velocity deviation vector Horizontal components, The sampling period is This refers to the length of the lifting rope.

[0040] In one specific embodiment, the pendulum angular velocity vector is obtained by the following formula:

[0041] in, This represents the current angular velocity vector of the spreader. The time interval between two adjacent sampling times, and when the change in the swing angle within Δt is less than the preset noise threshold. When the angle is 0.1°, the pendulum angular velocity vector is... Forced zeroing to prevent measurement noise amplification. The vector representing the horizontal swing angle at time t. The vector representing the horizontal swing angle at time t-1.

[0042] In this embodiment of the invention, the nonlinear anti-sway controller is designed based on Lyapunov stability theory and employs the following control law:

[0043] in, Indicates the speed compensation amount. This is a proportional feedback term used to provide the swing angle restoring torque; This is a differential feedback term used to provide oscillation damping; It is a nonlinear differential feedforward term, used to output reverse compensation in advance at the moment of acceleration and deceleration impact; , , These are the proportional gain coefficient, the differential gain coefficient, and the nonlinear differential feedforward coefficient, respectively. ; ; >0 represents the desired oscillation decay angular frequency; The damping ratio is in the range of 0.7. 1.0; makes the Lyapunov function The derivative of is greater than 0, and g is the acceleration due to gravity.

[0044] Furthermore, the controller also includes a gain adaptive scheduling module: which estimates the lifting weight in real time through feedback from the hoisting motor current. In conjunction with the real-time rope length L, it automatically adjusts according to a preset two-dimensional gain scheduling table. , , The possible values ​​of ; The adjustment rule for the gain scheduling table is to adjust the coefficients... , , Based on the set threshold, they are divided into three levels: large, medium, and small. when When the load is ≤ 0.3 times the rated load, the no-load gain group is used: Larger medium, Smaller; When 0.3 times the rated load < When the load is ≤ 0.8 times the rated load, the medium-load gain group should be used. medium, Larger medium; when When the load is greater than 0.8 times the rated load, the heavy-load gain group should be used. Smaller Larger Relatively large.

[0045] Furthermore, before inputting the swing angle vector and swing angular velocity vector as feedback quantities into the nonlinear anti-sway controller, the method further includes: a swing angle effectiveness determination step. Judge and compare the horizontal swing angle vector obtained by inversion Size relative to the preset threshold: when Then the horizontal swing angle vector The value is forcibly set to zero, and the nonlinear anti-sway controller does not trigger active compensation; when The nonlinear anti-sway controller then employs an incomplete control law. The speed compensation amount is obtained, where, Indicates the proportional gain coefficient; when The nonlinear anti-sway controller then employs a control law. The speed compensation amount is obtained; where, Indicates the speed compensation amount. This is a proportional feedback term used to provide the swing angle restoring torque; This is a differential feedback term used to provide oscillation damping; It is a nonlinear differential feedforward term, used to output reverse compensation in advance at the moment of acceleration and deceleration impact; , , These are the proportional gain coefficient, the differential gain coefficient, and the nonlinear differential feedforward coefficient, respectively. The minimum compensation threshold for the horizontal swing angle vector; The threshold for fully compensating for the horizontal swing angle vector.

[0046] In one specific implementation, the step of superimposing the speed compensation command onto the original command speed and outputting it to the frequency converter to drive the motor to perform reverse compensation motion further includes: Speed ​​compensation amount in speed compensation command Limit the amplitude: | | ≤ 0.3 · ,in This refers to the maximum operating speed of the corresponding mechanism; Speed ​​compensation after amplitude limiting The final speed is obtained by superimposing the original command speed. ; If the final speed >1.05 · This will trigger an overspeed warning and force the vehicle to stop. Attenuation of 50%; Continuously monitor the trend of the swing angle amplitude change. If the horizontal swing angle vector changes within three consecutive sampling periods... If the gain coefficient increases by more than 10% each time, the system is determined to be diverging. The gain coefficient of the nonlinear anti-sway controller is then reduced to 30% of the current value, and a fault alarm is issued.

[0047] In a second aspect, embodiments of the present invention also provide an active anti-sway control system for a tower crane according to any of the methods described in the first aspect, comprising: Sensing unit: at least one differential GPS mobile station mounted on the sling, and an optional six-axis IMU; Reference unit: A GPS reference station installed at a fixed location on the tower crane; Control unit: including industrial programmable controllers or embedded motion controllers that integrate Kalman filters, velocity deviation-swing angle observers, nonlinear anti-sway controllers, gain schedulers and safety logic modules; Actuation unit: includes frequency converters and motors that drive the luffing, slewing and hoisting mechanisms, and is connected to the control unit via real-time industrial Ethernet; Human-computer interaction unit: used to display real-time swing angle, compensation amount and alarm information.

[0048] 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.

[0049] 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 active anti-sway control of tower cranes based on GPS positioning of the lifting device, characterized in that, Includes the following steps: The three-dimensional spatial position of the lifting rig is obtained in real time by a GPS receiver installed on the rig; The actual velocity vector of the lifting device is calculated based on the position of the lifting device at adjacent moments; Obtain the commanded speed vector of the tower crane's motion mechanism, and calculate the deviation vector between the commanded speed vector and the actual motion speed vector; Based on the velocity deviation vector and the length of the lifting rope, the current horizontal swing angle vector and swing angular velocity vector of the lifting device are derived. The swing angle vector and swing angular velocity vector are used as feedback quantities and input to the nonlinear anti-sway controller to generate a speed compensation command. The speed compensation command is superimposed on the original command speed and output to the frequency converter to drive the motor to perform reverse compensation motion in order to suppress the sway of the lifting device.

2. The method according to claim 1, characterized in that, In the step of acquiring the three-dimensional spatial position of the lifting rig in real time via a GPS receiver installed on the rig, the GPS receiver employs a differential GPS system, including: At least one GPS mobile station installed on top of the spreader, and a GPS base station installed on the tower crane's fixed foundation section or at a stable ground position; The GPS base station receives satellite signals and generates differential correction signals; the GPS rover receives satellite signals and the differential correction signals, and calculates the three-dimensional spatial position of the lifting device based on the differential correction signals.

3. The method according to claim 1, characterized in that, The actual velocity vector of the spreader is calculated based on the position of the spreader at adjacent time points, specifically including: For each direction of motion of the spreader in the horizontal plane, a Kalman filter is constructed. The state of each Kalman filter includes the position p and velocity in that direction of motion. and acceleration a; Using the position in the direction of travel output by the GPS receiver as the observation value, and employing a uniform acceleration random walk model, the state transition matrix is ​​defined as follows: ; Define the process noise covariance matrix: in The sampling period is q, and the spectral density of the accelerometer is q. Define observation matrix The observation noise variance R is taken as the square of the GPS horizontal positioning accuracy; Perform the following sequentially for each sampling time k: Prediction Steps , ; Update steps: , , ; From the updated state vector Extracting velocity components The actual velocity in that direction: in, This represents the position p and velocity in the direction of motion at time k before the update. The state vector consisting of acceleration a; This represents the updated state vector at time k; This represents the updated state vector at time k-1; The prior estimate is the error covariance; The posterior estimation error covariance is used to represent the uncertainty measure after the update at the previous time step; Indicates Kalman gain; Let k represent the observation at time k, and I represent the identity matrix; The velocity components in the two orthogonal directions are combined to form the actual velocity vector of the lifting device. .

4. The method according to claim 1, characterized in that, The inversion process, which derives the current horizontal swing angle vector and swing angular velocity vector of the spreader, employs a velocity deviation-swing angle mapping model with a small-angle approximation to obtain the current horizontal swing angle vector of the spreader, as detailed below: in, This represents the current horizontal swing angle vector of the spreader. The dimensionless coefficients were obtained through on-site calibration. Represents the velocity deviation vector Horizontal components, The sampling period is This refers to the length of the lifting rope.

5. The method according to claim 1, characterized in that, In the step of inverting the current horizontal swing angle vector and swing angular velocity vector of the spreader, the swing angular velocity vector is obtained by the following formula: in, This represents the current angular velocity vector of the spreader. The time interval between two adjacent sampling times, and when the change in the swing angle within Δt is less than the preset noise threshold. When the angle is 0.1°, the pendulum angular velocity vector is... Forced zeroing to prevent measurement noise amplification. The vector representing the horizontal swing angle at time t. The vector representing the horizontal swing angle at time t-1.

6. The method according to claim 1, characterized in that, The nonlinear anti-sway controller is designed based on Lyapunov stability theory and adopts the following control law: in, Indicates the speed compensation amount. This is a proportional feedback term used to provide the swing angle restoring torque; This is a differential feedback term used to provide oscillation damping; It is a nonlinear differential feedforward term, used to output reverse compensation in advance at the moment of acceleration and deceleration impact; , , These are the proportional gain coefficient, the differential gain coefficient, and the nonlinear differential feedforward coefficient, respectively. ; ; >0 represents the desired oscillation decay angular frequency; The damping ratio is in the range of 0.

7. 1.0; makes the Lyapunov function The derivative of is greater than 0, and g is the acceleration due to gravity.

7. The method according to claim 6, characterized in that, The controller also includes a gain adaptive scheduling module: which estimates the lifting weight in real time through hoisting motor current feedback. In conjunction with the real-time rope length L, it automatically adjusts according to a preset two-dimensional gain scheduling table. , , The value of ; The adjustment rule for the gain scheduling table is to adjust the coefficients... , , Based on the set threshold, they are divided into three levels: large, medium, and small. when When the load is ≤ 0.3 times the rated load, the no-load gain group is used: Larger medium, Smaller; When 0.3 times the rated load < When the load is ≤ 0.8 times the rated load, the medium-load gain group should be used. medium, Larger medium; when When the load is greater than 0.8 times the rated load, the heavy-load gain group should be used. Smaller Larger Larger.

8. The method according to claim 1, characterized in that, Before inputting the swing angle vector and swing angular velocity vector as feedback quantities into the nonlinear anti-sway controller, the following step is also included: swing angle effectiveness determination step: Judge and compare the horizontal swing angle vector obtained by inversion Size relative to the preset threshold: when Then the horizontal swing angle vector The value is forcibly set to zero, and the nonlinear anti-sway controller does not trigger active compensation; when The nonlinear anti-sway controller then employs an incomplete control law. The speed compensation amount is obtained, where, Indicates the proportional gain coefficient; when The nonlinear anti-sway controller then employs a control law. The speed compensation amount is obtained; where, Indicates the speed compensation amount. This is a proportional feedback term used to provide the swing angle restoring torque; This is a differential feedback term used to provide oscillation damping; It is a nonlinear differential feedforward term, used to output reverse compensation in advance at the moment of acceleration and deceleration impact; , , These are the proportional gain coefficient, the differential gain coefficient, and the nonlinear differential feedforward coefficient, respectively. The minimum compensation threshold for the horizontal swing angle vector; The threshold for fully compensating for the horizontal swing angle vector.

9. The method according to claim 1, characterized in that, The step of superimposing the speed compensation command onto the original command speed and outputting it to the frequency converter to drive the motor to perform reverse compensation motion also includes: Speed ​​compensation amount in speed compensation command Limit the amplitude: | | ≤ 0.3 · ,in This refers to the maximum operating speed of the corresponding mechanism; Speed ​​compensation after amplitude limiting The final speed is obtained by superimposing the original command speed. ; If the final speed >1.05 · This will trigger an overspeed warning and force the vehicle to stop. Attenuation of 50%; Continuously monitor the trend of the swing angle amplitude change. If the horizontal swing angle vector changes within three consecutive sampling periods... If the gain coefficient increases by more than 10% each time, the system is determined to be diverging. The gain coefficient of the nonlinear anti-sway controller is then reduced to 30% of the current value, and a fault alarm is issued.

10. A tower crane active anti-sway control system implementing the method of any one of claims 1-9, characterized in that, include: Sensing unit: at least one differential GPS mobile station mounted on the sling, and an optional six-axis IMU; Reference unit: A GPS reference station installed at a fixed location on the tower crane; Control unit: including industrial programmable controllers or embedded motion controllers that integrate Kalman filters, velocity deviation-swing angle observers, nonlinear anti-sway controllers, gain schedulers and safety logic modules; Actuation unit: includes frequency converters and motors that drive the luffing, slewing and hoisting mechanisms, and is connected to the control unit via real-time industrial Ethernet; Human-computer interaction unit: used to display real-time swing angle, compensation amount, and alarm information.

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