Four-rotor anti-rolling lifting hook of marine crane and control device and control method of four-rotor anti-rolling lifting hook

Abstract

The invention discloses a four-rotor anti-rolling lifting hook of a marine crane and a control device and a control method of the four-rotor anti-rolling lifting hook, and belongs to the technical field of ocean engineering equipment. Aiming at the problems of insufficient multi-degree-of-freedom control capability, low thrust distribution precision, slow dynamic response and the like of the existing stabilization device, the invention provides a square lifting hook body, four independent rotor wing units are symmetrically mounted at four corners of the square lifting hook body, and the thrust directions of rotor wings are in the radial direction of a lifting hook and are opposite to the rotating directions of the rotor wings; and efficient stabilization is realized by combining multi-sensor fusion and a dynamic thrust distribution mechanism. The control device is integrated with a PLC, a servo driver, an inertial measurement unit and an encoder, and a high-speed control network is constructed through Ethernet and wireless communication; the control method is based on real-time displacement, speed and load mass of a lifting hook, target thrust is generated through a proportional-differential algorithm and converted into independent instructions of all rotors through a radial thrust distribution matrix, and torque balance is optimized in combination with a pseudo-inverse method. In addition, a mass compensation model is introduced to dynamically correct a thrust coefficient, and nonlinear errors caused by load changes are inhibited. The device has the advantages of compact structure, high response speed, strong anti-interference capability and the like, and the stability and the operation safety of the lifting hook under the complex sea condition are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of ship engineering technology, and in particular to a ship crane hook that realizes efficient anti-rolling through quad-rotor dynamic coupling control and a mechanical linkage structure, and a control device and method thereof. Background Art

[0002] With the rapid development of marine resource development and maritime transportation, marine cranes, as key equipment, are widely used in cargo loading and unloading, maritime rescue, and deep-sea engineering operations. However, in complex marine environments, ships are prone to rolling and pitching motions due to disturbances such as waves and wind, causing the crane hook and suspended cargo to swing violently. This swing not only reduces operational efficiency but also may cause safety hazards such as cargo collisions and rope breakage. Therefore, how to effectively suppress the swing of the hook and cargo (i.e., "roll reduction") has become one of the core challenges in improving the performance of marine cranes.

[0003] Currently, technologies for hook sway reduction are mainly divided into two categories: passive and active. Passive sway reduction devices (such as mechanical dampers and counterweight balancing systems) absorb energy through structural design, but their response speed is slow, the adjustment range is limited, and they are difficult to adapt to dynamic sea conditions. Active sway reduction systems offset sway by applying a reaction force in real time. Common solutions include hydraulic drive mechanisms and thrusters, but their structures are complex, energy consumption is high, and the suppression effect of high-frequency disturbances is insufficient. In recent years, rotor propulsion technology has been introduced into the field of sway reduction due to its fast response and precise thrust distribution. However, existing rotor propulsion solutions have the following problems: 1) Thrust distribution is limited and cannot simultaneously suppress sway in multiple degrees of freedom; 2) Control accuracy is insufficient, multi-sensor data is not integrated, and thrust distribution relies on static models, which makes it difficult to cope with sudden changes in load mass or complex external force interference; 3) Dynamic adaptability is poor and there is a lack of compensation mechanism for the nonlinear characteristics of rotor thrust, resulting in a large deviation between the actual thrust and the theoretical value, affecting the sway reduction effect.

[0004] Therefore, existing ship crane anti-roll technology generally suffers from problems such as high structural redundancy, slow dynamic response, and insufficient multi-degree-of-freedom control capabilities. Therefore, a anti-roll system integrating efficient thrust distribution, multi-sensor fusion, and adaptive compensation mechanisms is urgently needed to achieve rapid hook stabilization in complex sea conditions. Summary of the Invention

[0005] The purpose of this invention is to provide a four-rotor dynamic coupling anti-roll hook system for marine cranes, which solves the existing technical problems through innovative mechanical structure and intelligent control methods. The specific technical solution is as follows:

[0006] The first object of the present invention is to provide a four-rotor anti-roll hook for a marine crane, comprising a hook body, a rotor unit, and a control device. The hook body is square, and the center position of the top is connected to the main sling via a weighing sensor. The rotor unit comprises four independently rotatable rotors, with the rotation axis being horizontal and symmetrically mounted at the four corners of the hook body. The rotor blade angles are fixed to preset values, and the thrust direction of each rotor is radial to the hook body (i.e., relative to the direction of the line connecting the centers of the two rotors). When the two opposing rotors generate thrust, their rotation directions are opposite. The control device dynamically distributes rotor thrust by fusing data from multiple sensors.

[0007] The second object of the present invention is to provide a control device for a four-rotor anti-roll hook of a ship crane, which is applied to the hook. The control device consists of a first encoder to a fifth encoder, a PLC, an Ethernet module, a wireless router, an industrial computer, a wireless network card, a first servo drive to a fourth servo drive, a first servo motor to a fourth servo motor, an inertial measurement unit and a weighing sensor; the first encoder to the fourth encoder are correspondingly installed on the tail shafts of the first servo motor to the fourth servo motor, and the output shafts of the first servo motor to the fourth servo motor are respectively connected to the rotor unit; the fifth encoder is installed on the fixed pulley shaft of the sling above the hook; the PLC, Ethernet module, wireless router, the first servo drive to the fourth servo drive, the first servo motor to the fourth servo motor, and the inertial measurement unit are all installed inside the hook body, wherein the inertial measurement unit is installed on the base plate at the center of gravity of the hook body.

[0008] Furthermore, the PLC has specific input pins that can collect encoder A and B phase signals; the wireless router has at least 6 wired network ports; the inertial measurement unit and weighing sensor both output signals through wired network ports; the first to fourth servo drives all support wired network communication control mode.

[0009] Furthermore, the output of the fifth encoder is connected to the switch input pin of the PLC; the PLC is connected to the wireless router through the Ethernet module; the wireless router is connected to the first servo drive to the fourth servo drive, the inertial measurement unit and the weighing sensor through network cables; the signals of the first encoder to the fourth encoder are output to the first servo drive to the fourth servo drive respectively; the industrial computer establishes communication with the PLC wirelessly through the wireless router and the Ethernet module through the wireless network card.

[0010] A third object of the present invention is to provide a control method for a four-rotor anti-roll hook for a marine crane, which is applied to the hook, and the method comprises the following steps:

[0011] Step 1: The PLC obtains the horizontal acceleration and attitude angle data of the hook body in real time through the inertial measurement unit on the hook and sends it to the industrial computer; the industrial computer calculates the real-time displacement x, y and speed of the hook body in the horizontal plane based on the acceleration data and the rope length. PLC 2 obtains the total mass m of the hook and the weight through the weighing sensor and sends it to the industrial computer;

[0012] Step 2: The industrial computer generates the target thrust F using the proportional-differential control algorithm based on the displacement, velocity and total mass obtained through communication with the PLC. t =[F x ,F y ] T ,in,

[0013]

[0014] Proportional gain

[0015] Differential gain

[0016] m0 is the design basis mass, k p0 is the proportional gain corresponding to the design reference mass, k d0 The corresponding differential gain when designing the reference mass;

[0017] Step 3: The industrial computer uses the radial thrust distribution matrix A to calculate the target thrust F t Convert to independent thrust commands for the four rotors [F1, F2, F3, F4] T ,satisfy:

[0018]

[0019] The first two rows of matrix A describe the combined thrust on the X / Y axis, and the third row ensures that the moment around the Z axis is 0. Its specific form is:

[0020]

[0021] θ i is the angle between the thrust direction of each rotor and the X-axis, and d is the distance from the rotor to the center of the hook;

[0022] Step 4: The industrial computer generates the thrust command F t , through a pre-calibrated nonlinear model (n i The target speed is calculated and sent to the PLC (where c(m) is the speed and c(m) is the mass-related thrust coefficient). The PLC uses PID control to adjust the motor speed, and the industrial computer dynamically corrects c(m) through acceleration feedback to suppress the thrust error caused by mass changes.

[0023] Furthermore, the construction of the radial thrust distribution matrix A in step 3 satisfies the following conditions:

[0024] The axes of rotors 1 and 3 are along the positive and negative directions of the X-axis, with angles θ1 = 0° and θ3 = 180°. The axes of rotors 2 and 4 are along the positive and negative directions of the Y-axis, with angles θ2 = 90° and θ4 = 270°. When rotors 1 and 3 push outward (F1, F3>0), rotors 2 and 4 pull inward (F2, F4<0), so that the torque terms automatically cancel each other out. The solution to the matrix equation is obtained using the pseudo-inverse method:

[0025]

[0026] Among them A + is the Moore-Penrose pseudoinverse of matrix A.

[0027] Furthermore, the mass compensation of the thrust coefficient c(m) in step 4 is achieved by the following steps:

[0028] The thrust-speed curve under different mass m is calibrated offline by the industrial computer and fitted Where α is the mass influence factor and c0 is the reference thrust coefficient. The industrial computer updates c(m) in real time through the weighing sensor during the online stage and constrains the speed command to meet the following requirements:

[0029]

[0030] When the industrial computer detects that the deviation between the actual acceleration and the theoretical value exceeds the threshold, the α value is reversely optimized to correct the model error.

[0031] The present invention has the following beneficial effects

[0032] 1) Through the symmetrical layout of the quadrotor units and the radial thrust direction design, combined with the dynamic thrust distribution matrix and torque balance optimization, a resultant force can be generated on the hook horizontal plane (X / Y axis) to offset the rotational torque, effectively suppressing multi-degree-of-freedom swing.

[0033] 2) By integrating real-time data from the inertial measurement unit (IMU), load cells, and multiple encoders, and combining them with a proportional-differential control algorithm, the system's response speed to high-frequency disturbances such as waves and wind is significantly improved. The thrust coefficient is dynamically corrected through a mass compensation model to reduce the impact of sudden load changes or nonlinear factors on control accuracy, ensuring stable thrust output.

[0034] 3) Thrust commands are distributed through the pseudo-inverse method to minimize the total energy consumption of the rotor; it supports adaptive parameter matching in different lifting scenarios, expanding the applicability of the system under light load, heavy load and dynamic sea conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a schematic diagram of a four-rotor anti-roll hook for a marine crane according to the present invention;

[0037] Figure 2 This is a block diagram of the control device for a four-rotor anti-roll hook for a marine crane according to the present invention; DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0039] like Figure 1 Figure 2 is a schematic diagram of a four-rotor anti-roll hook for a marine crane according to the present invention, comprising a hook body 21, a rotor unit 22, and a control device 30. The hook body 21 is square, and the center position of the top is connected to the main sling via a weighing sensor 20. The rotor unit 22 comprises four independently rotatable rotors, with the rotation axis symmetrically mounted at the four corners of the hook body 21 along the horizontal direction. The rotor blade angles are fixed to preset values, and the thrust direction of each rotor is radial to the hook body 21 (i.e., relative to the direction of the line connecting the centers of the two rotors). When the two opposing rotors generate thrust, their rotation directions are opposite. The control device 30 dynamically distributes rotor thrust by fusing data from multiple sensors.

[0040] like Figure 2The figure shows a block diagram of the control device for a four-rotor anti-roll hook for a marine crane according to the present invention. The control device 30 comprises first to fifth encoders 9 to 1, a programmable logic controller (PLC) 2, an Ethernet module 3, a wireless router 4, an industrial computer 5, a wireless network card 6, first to fourth servo drivers 7 to 16, first to fourth servo motors 8 to 17, an inertial measurement unit 19, and a load cell 20. The first to fourth encoders 9 to 18 are correspondingly mounted on the tail shafts of the first to fourth servo motors 8 to 17, and the output shafts of the first to fourth servo motors 8 to 17 are respectively connected to the rotor unit 22. The fifth encoder 1 is mounted on the fixed pulley shaft of the sling above the hook. The PLC 2, Ethernet module 3, wireless router 4, first to fourth servo drivers 7 to 16, first to fourth servo motors 8 to 17, and inertial measurement unit 19 are all mounted inside the hook body 21, wherein the inertial measurement unit 19 is mounted on the bottom plate at the center of gravity of the hook body 21.

[0041] In one embodiment, the PLC 2 has specific input pins capable of acquiring encoder A and B phase signals; the wireless router 4 has at least six wired network ports; the inertial measurement unit 19 and load cell 20 both output signals via wired network ports; and the first through fourth servo drivers 7 through 16 all support wired network communication control. The output of the fifth encoder 1 is connected to a switch input pin of the PLC 2; the PLC 2 is connected to the wireless router 4 via the Ethernet module 3; the wireless router 4 is connected to the first through fourth servo drivers 7 through 16, the inertial measurement unit 19, and the load cell 20 via network cables; the signals of the first through fourth encoders 9 through 18 are respectively output to the first through fourth servo drivers 7 through 16; and the industrial computer 5 establishes wireless communication with the PLC 2 via the wireless network card 6 via the wireless router 4 and Ethernet module 3.

[0042] To further illustrate the control principle of the hook, the control method adopted includes the following steps:

[0043] Step 1: PLC2 obtains the horizontal acceleration and attitude angle data of the hook body 21 in real time through the inertial measurement unit 19 on the hook and sends it to the industrial computer 5; the industrial computer 5 calculates the real-time displacement x, y and speed of the hook body 21 in the horizontal plane based on the acceleration data and the rope length. PLC2 obtains the total mass m of the hook and the weight through the weighing sensor 20 and sends it to the industrial computer 5;

[0044] Step 2: The industrial computer 5 generates the target thrust F using the proportional-differential control algorithm based on the displacement, velocity and total mass. t =[F x ,Fy ] T ,in,

[0045]

[0046] Proportional gain

[0047] Differential gain

[0048] m0 is the design basis mass, k p0 is the proportional gain corresponding to the design reference mass, k d0 The corresponding differential gain when designing the reference mass;

[0049] Step 3: The industrial computer 5 uses the radial thrust distribution matrix A to distribute the target thrust F t Convert to independent thrust commands for the four rotors [F1, F2, F3, F4] T ,satisfy:

[0050]

[0051] The first two rows of matrix A describe the combined thrust on the X / Y axis, and the third row ensures that the moment around the Z axis is 0. Its specific form is:

[0052]

[0053] θ i is the angle between the thrust direction of each rotor and the X-axis, and d is the distance from the rotor to the center of the hook;

[0054] Step 4: The industrial computer 5 generates the thrust command F t , through a pre-calibrated nonlinear model (n i The target speed is calculated (where c(m) is the mass-related thrust coefficient) and sent to PLC 2. PLC 2 uses PID control to adjust the motor speed, and through acceleration feedback, industrial computer 5 dynamically corrects c(m) to suppress thrust errors caused by mass changes.

[0055] The construction of the radial thrust distribution matrix A described in step 3 above satisfies the following conditions:

[0056] The axes of rotors 1 and 3 are along the positive and negative directions of the X-axis, with angles θ1 = 0° and θ3 = 180°. The axes of rotors 2 and 4 are along the positive and negative directions of the Y-axis, with angles θ2 = 90° and θ4 = 270°. When rotors 1 and 3 push outward (F1, F3>0), rotors 2 and 4 pull inward (F2, F4<0), so that the torque terms automatically cancel each other out. The solution to the matrix equation is obtained using the pseudo-inverse method:

[0057]

[0058] Among them A + is the Moore-Penrose pseudoinverse of matrix A.

[0059] The mass compensation of the thrust coefficient c(m) described in step 4 above is achieved by the following steps:

[0060] The thrust-speed curves under different mass m are calibrated offline by the industrial computer 5, and fitted Where α is the mass influence factor and c0 is the reference thrust coefficient. The industrial computer 5 updates c(m) in real time through the weighing sensor 20 during the online phase and constrains the speed command to meet the following requirements:

[0061]

[0062] When the industrial computer 5 detects that the deviation between the actual acceleration and the theoretical value exceeds a threshold, the α value is reversely optimized to correct the model error.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A four-rotor anti-roll hook for a marine crane, comprising a hook body (21), a rotor unit (22) and a control device (30), characterized in that: The hook body (21) is square in shape, and the center position of the top is connected to the main sling via a weighing sensor (20); the rotor unit (22) comprises four rotors, which can rotate independently, and the rotation axis is horizontally arranged symmetrically at the four corners of the hook body (21); the rotor blade angle is fixed to a preset value, and the thrust direction of each rotor is radially along the hook body (21) (i.e., relative to the direction of the line connecting the centers of the two rotors), and the rotation directions of the two opposite rotors are opposite when they generate thrust; the control device (30) dynamically distributes the rotor thrust by fusing data from multiple sensors.

2. A hook control device, applied to the hook according to claim 1, characterized in that: The control device (30) is composed of a first encoder (9) to a fifth encoder (1), a PLC (2), an Ethernet module (3), a wireless router (4), an industrial computer (5), a wireless network card (6), a first servo driver (7) to a fourth servo driver (16), a first servo motor (8) to a fourth servo motor (17), an inertial measurement unit (19) and a weighing sensor (20); the first encoder (9) to the fourth encoder (18) are correspondingly installed on the tail shafts of the first servo motor (8) to the fourth servo motor (17), and the first The output shafts of the servo motor (8) to the fourth servo motor (17) are respectively connected to the rotor unit (22); the fifth encoder (1) is installed on the fixed pulley shaft of the sling above the hook; the PLC (2), the Ethernet module (3), the wireless router (4), the first servo driver (7) to the fourth servo driver (16), the first servo motor (8) to the fourth servo motor (17), and the inertial measurement unit (19) are all installed inside the hook body (21), wherein the inertial measurement unit (19) is installed on the bottom plate at the center of gravity of the hook body (21).

3. A hook control device according to claim 2, characterized in that: The PLC (2) has specific input pins capable of collecting encoder A and B phase signals; the wireless router (4) has at least six wired network ports; the inertial measurement unit (19) and the weighing sensor (20) both output signals via wired network ports; and the first servo driver (7) to the fourth servo driver (16) all support a wired network communication control mode.

4. A hook control device according to claim 2, characterized in that: The output of the fifth encoder (1) is connected to the switch input pin of the PLC (2); the PLC (2) is connected to the wireless router (4) via the Ethernet module (3); the wireless router (4) is respectively connected to the first servo driver (7) to the fourth servo driver (16), the inertial measurement unit (19) and the weighing sensor (20) via network cables; the signals of the first encoder (9) to the fourth encoder (18) are respectively output to the first servo driver (7) to the fourth servo driver (16); the industrial computer (5) establishes communication with the PLC (2) in a wireless manner via the wireless router (4) and the Ethernet module (3) through the wireless network card (6).

5. A method for controlling a hook, applied to the hook according to claim 1, characterized in that: The method comprises the following steps: Step 1: The PLC (2) obtains the horizontal acceleration and attitude angle data of the hook body (21) in real time through the inertial measurement unit (19) on the hook and sends it to the industrial computer (5); the industrial computer (5) calculates the real-time displacement x, y and speed of the hook body (21) in the horizontal plane based on the acceleration data and the rope length. The PLC (2) obtains the total mass m of the hook and the weight through the weighing sensor (20) and sends it to the industrial computer (5); Step 2: The industrial computer (5) generates the target thrust F using the proportional-differential control algorithm based on the displacement, velocity and total mass. t =[F x ,F y ] T ,in, Proportional gain Differential gain m0 is the design basis mass, k p0 is the proportional gain corresponding to the design reference mass, k d0 The corresponding differential gain when designing the reference mass; Step 3, the industrial computer (5) uses the radial thrust distribution matrix A to distribute the target thrust F t Convert to independent thrust commands for the four rotors [F1, F2, F3, F4] T ,satisfy: The first two rows of matrix A describe the combined thrust on the X / Y axis, and the third row ensures that the moment around the Z axis is 0. Its specific form is: θ i is the angle between the thrust direction of each rotor and the X-axis, and d is the distance from the rotor to the center of the hook; Step 4, the industrial computer (5) calculates the thrust command F t , through a pre-calibrated nonlinear model (n i is the speed, c(m) is the mass-related thrust coefficient) and calculates the target speed and sends it to PLC (2); PLC (2) uses PID control to adjust the motor speed, and through acceleration feedback, the industrial computer (5) dynamically corrects c(m) to suppress the thrust error caused by mass change.

6. A method for controlling a hook according to claim 5, characterized in that: The construction of the radial thrust distribution matrix A described in step 3 satisfies the following conditions: The axes of rotors 1 and 3 are along the positive and negative directions of the X-axis, with angles θ1 = 0° and θ3 = 180°. The axes of rotors 2 and 4 are along the positive and negative directions of the Y-axis, with angles θ2 = 90° and θ4 = 270°. When rotors 1 and 3 push outward (F1, F3>0), rotors 2 and 4 pull inward (F2, F4<0), so that the torque terms automatically cancel each other out. The solution to the matrix equation is obtained using the pseudo-inverse method: Among them A + is the Moore-Penrose pseudoinverse of matrix A.

7. The method for controlling a hook according to claim 5, characterized in that: The mass compensation of the thrust coefficient c(m) described in step 4 is achieved by the following steps: The industrial computer (5) offline calibrates the thrust-speed curve under different mass m and fits Where α is the mass influence factor, c0 is the reference thrust coefficient; the industrial control computer (5) updates c(m) in real time through the weighing sensor (20) during the online stage, and constrains the speed command to meet: When the industrial control computer (5) detects that the deviation between the actual acceleration and the theoretical value exceeds a threshold, the α value is reversely optimized to correct the model error.

Images