Dynamic compensation mechanical arm mechanism of marine ship crane

Abstract

The invention discloses a dynamic compensation mechanical arm mechanism of an ocean ship crane, which comprises a rack, a mechanical arm, a mechanical arm and a mechanical arm, the left mechanical arm and the right mechanical arm are symmetrically hinged with the rack left and right; two mechanical rods are hinged to the left mechanical arm and the right mechanical arm respectively, a winch is fixed to one mechanical rod, a steel wire rope pulley is arranged at the tail end of the mechanical rod fixing the winch, and a steel wire rope of the winch bypasses the steel wire rope pulley to be connected with a lifting hook; the two hydraulic oil cylinders are fixed on the rack; the monitoring unit is used for measuring the rotation angle and speed of the winch to obtain the pendulum length of the steel wire rope and the speed of the lifting hook at the current moment and measuring the distance and transverse displacement of the lifting hook relative to the balance position; and the controller is used for calculating the control quantity according to the data measured by the monitoring unit, obtaining the hydraulic oil flow of the hydraulic oil cylinder, controlling one of the mechanical arms to rotate, and driving the lifting hook to move so as to restrain the swinging of the lifting hook. And the shaking compensation of the lifting hook can be realized in the horizontal direction.

Description

Technical Field

[0001] The invention belongs to the field of cranes, and in particular relates to a dynamic compensation mechanical arm mechanism of a marine ship crane. Background Art

[0002] With the increasing demands of offshore engineering operations, especially the recent growth of the offshore wind power industry, increasingly stringent requirements are being placed on offshore marine cranes. Traditional ship cranes only provide heave compensation, but cannot eliminate the impact of wind on lifting operations, thus failing to ensure safe, precise, and efficient operations.

[0003] For example, multi-rope mechanical anti-sway devices suppress sway through the interaction of multiple steel ropes. However, improper maintenance of the steel ropes will shorten their service life and increase maintenance costs. Their anti-sway effect is also limited by sea conditions and operating conditions, and cannot achieve optimal results in all situations. Rigid anti-sway systems use rigid connections to reduce the sway of the load, but their effect on suppressing large swings is limited and they put great pressure on the crane structure itself. In high wind speeds or complex sea conditions, they cannot provide sufficient anti-sway effect. Mechanical anti-sway systems reduce sway by adding mechanical equipment, such as cross-wire anti-sway, separate driving anti-sway, and seesaw beam anti-sway devices. Although these systems are highly precise, they are complex in structure, expensive, difficult to maintain, and may affect the total weight and lifting capacity of the crane. Summary of the Invention

[0004] The purpose of the present invention is to provide a dynamic compensation mechanical arm mechanism for a marine ship crane, which monitors the relative position of the hook in real time through a sensor, and controls the hydraulic cylinder to drive the mechanical arm to rotate by a controller, so that the mechanical arm can compensate for the shaking of the hook in the horizontal direction.

[0005] The technical solutions for achieving the purpose of the present invention are:

[0006] A dynamic compensation mechanical arm mechanism for a marine ship crane, comprising:

[0007] A frame for connecting to a marine vessel crane;

[0008] Left and right robotic arms symmetrically articulated with the frame;

[0009] Two mechanical rods are respectively hinged to the left and right mechanical arms, a winch is fixed on one of the mechanical rods, a wire rope pulley is provided at the end of the mechanical rod fixing the winch, and the wire rope of the winch passes through the wire rope pulley and is connected to the hook;

[0010] Two hydraulic cylinders fixed to the frame are used to drive one of the robotic arms to rotate;

[0011] The monitoring unit is used to measure the rotation angle and speed of the winch to obtain the swing length of the wire rope and the current speed of the hook, and to measure the distance and lateral displacement of the hook relative to the equilibrium position;

[0012] The controller is used to calculate the control quantity according to the data measured by the monitoring unit, obtain the hydraulic oil flow of the hydraulic cylinder, control the rotation of one of the mechanical arms, and drive the hook to move to suppress the swing of the hook.

[0013] Compared with the prior art, the present invention has the following significant advantages:

[0014] The present invention provides a dynamic compensation mechanical arm mechanism for a marine ship crane, in which the lifting winch is directly mounted on the mechanical arm, and all compensation is completed on the mechanical arm, without the need to compensate the entire crane mechanism, thereby improving compensation performance and reducing energy consumption; and adopts a universal connection structure, which can be expanded to a variety of traditional folding arm cranes to improve their anti-sway performance; in addition, the oil cylinder drives the left and right mechanical arms to compensate on the horizontal plane, and the winch can compensate on the vertical axis, thereby realizing the overall 3D dynamic compensation function; in addition, the left and right mechanical arms are connected to the frame by bearings, and the mechanical arm has a large rotation angle, which makes the motion compensation area larger, significantly improves the anti-sway performance, and improves the adaptability to extreme sea conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a three-dimensional diagram of the overall structure of the device of the present invention;

[0016] Figure 2 It is a front view of the overall structure of the device of the present invention;

[0017] Figure 3 For the present invention Figure 2 Cross-sectional view along AA;

[0018] Figure 4 For the present invention Figure 2 Enlarged view of point B in the middle;

[0019] Figure 5 A three-dimensional diagram of the frame structure of the device of the present invention;

[0020] Figure 6 This is a motion compensation range diagram of the device of the present invention;

[0021] Figure 7 This is a perspective view of the right mechanical rod structure of the device of the present invention;

[0022] Figure 8 This is a front view of the right mechanical rod structure of the device of the present invention;

[0023] Figure 9 This is a schematic diagram of the relative positions of the hooks of the present invention;

[0024] The reference numerals are as follows:

[0025] 1. Mechanism center position, 2. Minimum outward extension position, 3. Maximum outward extension position, 4. Maximum left outward extension position, 5. Maximum right outward extension position, 6. Minimum left outward extension position, 7. Minimum right outward extension position, 8. Frame, 9. Right robotic arm, 10. Left robotic arm, 11. Right mechanical rod, 12. Left mechanical rod, 13. Hydraulic cylinder, 14. Plane bearing, 15. Gasket, 16. Pipe cap, 17. Bolt group, 18. Connecting ring, 19. Connecting block, 20. Hydraulic cylinder output end, 21. Mounting plate, 22. Hydraulic cylinder connecting plate, 23. Ultrasonic sensor, 24. Winch encoder, 25. Light, 26. Winch outer frame, 27. Winch, 28. Shackle, 29. Wire rope, 30. Wire rope pulley, 31. Relative position of wire rope pulleys, 32. Relative position of hooks. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] like Figure 1-2 As shown, the present invention provides a dynamic compensation mechanical arm mechanism for a marine ship crane, comprising: a frame 8, a right mechanical arm 9, a left mechanical arm 10, a right mechanical rod 11, a left mechanical rod 12, and a hydraulic cylinder 13. The frame 8 is connected to the right mechanical arm 9 and the left mechanical arm 10 via hinges, respectively. The right mechanical arm 9 and the right mechanical rod 11, the left mechanical arm 10 and the left mechanical rod 12, and the right mechanical rod 11 and the left mechanical rod 12 are also connected via hinges, allowing each part to rotate relative to each other around a fixed axis. Simultaneously, a closed pentagonal structure is formed, wherein the frame is connected and fixed to the crane, while the other components can rotate around the axis. Two hydraulic cylinders 13 are fixed to the bottom of the frame 8 by a bolt group and connected to the right mechanical arm 9.

[0028] like Figure 3 As shown, the connection method between the frame 8 and the right robotic arm 9 is shown in detail. The plane bearing 14 connects the frame 8 and the right robotic arm 9, so that the right robotic arm 9 can rotate around the hinge axis. The plane bearing 14 is fixed by the pipe cap 16 and the bolt group 17, and impurities in the environment are prevented from entering, ensuring the smooth rotation of the right robotic arm 9. The relative position with the frame is fixed by the gasket 15. Similarly, the other structural components of this anti-sway robotic arm adopt the same connection method, such as the mutual connection between the right robotic arm 9, the left robotic arm 10, the right mechanical rod 11 and the left mechanical rod 12, so that each component can rotate around the connection axis to achieve maximum structural flexibility.

[0029] like Figure 4-5As shown, the frame 8 is hingedly connected to the arm of the marine crane via a mounting plate 21, allowing the frame 8 to rotate about the connecting axis. The hydraulic cylinder 13 is fixed in position by a connecting ring 18; a hydraulic cylinder connecting plate 22 is provided on the frame 8. The hydraulic cylinder 13, connecting block 19, and hydraulic cylinder connecting plate 22 are connected and secured by a bolt assembly, improving the stability of the fixation and preventing the hydraulic cylinder 13 from loosening. The two output ends 20 of the hydraulic cylinder 13 are respectively connected to the right arm 9 via hinges. When the hydraulic cylinder output ends 20 are in operation, the two output ends of the hydraulic cylinder 13 are adjusted to output different forces (one extending, the other retracting), thereby controlling the rotation direction of the right arm 9.

[0030] like Figure 6 The figure shows the operating range of the dynamic compensation arm mechanism, including: center position 1, minimum extension position 2, maximum extension position 3, maximum left extension position 4, maximum right extension position 5, minimum left extension position 6, and minimum right extension position 7. The area enclosed by these six extreme positions represents the dynamic compensation range of the dynamic compensation arm mechanism. By driving cylinder 13 to drive the right arm 9 to different rotation angles, the front end of the arm can be moved to various positions within the dynamic compensation range, achieving dynamic compensation of the arm in the horizontal direction. When the ship moves and the hook shakes, the front end of the arm moves within this range, offsetting the hook's shaking and achieving anti-sway effect in the horizontal plane. When the arm stops working, it is in minimum extension position 2 to reduce the occupied volume.

[0031] like Figure 7-8 As shown, the rear end of the right mechanical rod 11 is connected to the winch outer frame 26 via a bolt group. The winch outer frame 26 is fixed to the winch 27 via a bolt group. The wire rope 29 is wrapped around the winch 27 and connected to the hook through a shackle 28 and a wire rope pulley 30. The shackle 28 and wire rope pulley 30 are both fixed to the right mechanical rod 11, and the wire rope pulley 30 is located at the front end of the right mechanical rod 11. The winch 27 is equipped with a winch encoder 24 via a bolt group. The winch encoder 24 is a sensor device used in the winch system. It is mainly used to monitor and record the movement of the wire rope 29 during the operation of the winch 27, measure the rotation angle and speed of the winch 27 in real time, and thus calculate the retraction and extension length and speed of the wire rope 29. The front end of the right mechanical rod 11 is equipped with an ultrasonic sensor 23. The ultrasonic sensor 23 measures the real-time position of the hook vertically downward. Data from the winch encoder 24 and ultrasonic sensor 23 is transmitted to the mechanism's controller, which calculates the output torque of the drive cylinder 13, thereby rotating the right mechanical arm 9 and compensating for hook swing. A light 25 is bolted to the right mechanical lever 11, allowing the operator to clearly observe the position of the hook and the load during nighttime operations.

[0032] The working principle of this device:

[0033] First, the dynamic compensation mechanical arm mechanism is installed on the mechanical arm of the marine ship crane, and the hook is installed at the end of the wire rope 29. Figure 9 As shown, when the crane is operating and the hook is lifting a load, the winch encoder 24 monitors the movement of the wire rope 29 in real time, obtaining the swing length L of the wire rope 29, which is the length between the relative position of the wire rope pulley 31 and the relative position of the hook 32. At the same time, the ultrasonic sensor 23 measures the distance X and the lateral displacement Y of the hook relative to the equilibrium position. Based on the geometric relationship, the formula: and Calculate the longitudinal swing angle θ of the hook relative to the equilibrium position 实际 and lateral swing angle α 实际 .

[0034] Secondly, the winch encoder measures the current hook velocity v(t) in real time, and the instantaneous acceleration of the hook is calculated using the differential algorithm: Where Δt is the time difference. Use the acceleration a(t) to predict the future swing trend and generate the compensation signal in advance: u 前馈 =K ff a(t) Δt, where Δt is the time difference, K ff is the feedforward gain coefficient, K ff Dynamic adjustment based on the sea conditions during operation. When a sudden change in hook acceleration is detected (such as a gust of wind), the feedforward signal drives the actuator in advance to reduce feedback delay.

[0035] Again, θ 实际 and α 实际 Considered as longitudinal and lateral error sources respectively, two independent error signals are defined: longitudinal error e θ (t) = θ 目标 -θ 实际 and lateral error e α (t) = α 目标 -α 实际 .

[0036] Next, independent PID controllers are designed for the longitudinal and transverse directions.

[0037] Vertical:

[0038] Horizontal:

[0039] Where t is the time variable, K pθ ,K iθ ,K dθ are the proportional, integral and differential coefficients of the longitudinal control loop, K pα ,K iα,K dα The proportional, integral and differential coefficients of the lateral control loop must be determined through on-site debugging and optimization.

[0040] Then, combined with the periodic wave model Generate predictive control signal u 预测 =K 预测 ·S·Δt, where (T is the wave period) indicates the speed of the wave periodic change, L is the pendulum length, is the initial phase offset of the sine function, indicating the starting position of the wave on the time axis, Δt is the time difference, K 预测 In order to predict the gain coefficient, it needs to be determined through experimental debugging.

[0041] Then, the PID feedback signal is combined with the prediction signal and the feedforward signal to generate the total control quantity: u 总 =u θ (t)+u α (t)+u 前馈 +u 预测 .

[0042] Finally, the generated signal is transmitted to the controller of the robot arm. The controller calculates the generated control signal u based on the variables such as the distance X of the hook relative to the equilibrium position, the lateral displacement Y and the current speed v(t) measured by the ultrasonic sensor 23 and the winch encoder 24. 总 Control the anti-sway hydraulic system control module to work. The two hydraulic cylinders are A and B, and the total control amount u 总 Need to be decomposed into the control signal u of two hydraulic cylinders A and u B , making the output forces of the two cylinders unequal, generating a net torque to drive the robot arm to rotate. Distribution formula: u A =u 总 k,u B =u 总 (1-k), where k is the distribution coefficient, k∈[0,0.5] or k∈[0.5,1], which is adjusted according to the rotation direction of the right robot arm 9. Control signal u A and u B By formula: Calculate the hydraulic oil flow of hydraulic cylinders A and B respectively, where Q A , Q B : Hydraulic oil flow of hydraulic cylinders A and B, k qA , K qB : Servo valve flow coefficient of hydraulic cylinders A and B, Δp A ,Δp B : The pressure difference between the valve ports of hydraulic cylinders A and B. This controls the flow of cylinders A and B and adjusts the driving force of the hydraulic cylinders.A and u B The hydraulic servo valve drives the cylinder displacement, which is converted into the rotation angle of the robotic arm, ultimately achieving dynamic compensation of the hook position. The entire process is achieved through a closed-loop linkage of PID feedback, feedforward prediction, and hydraulic dynamics modeling, ensuring rapid and stable hook operation in complex sea conditions.

[0043] In general, when the ship sways with the waves, the hook also sways. The winch encoder 24 and ultrasonic sensor 23 measure the real-time position of the hook, and the controller calculates the driving force transmitted to the right mechanical arm 9 by the driving cylinder 13. After that, the anti-sway hydraulic system control module drives the hydraulic cylinder 13 to work, and the hydraulic cylinder 13 drives the right mechanical arm 9 to rotate around the axis. The rotation of the right mechanical arm 9 is transmitted to the end of the right mechanical rod 11, so that the hook connected to the end of the right mechanical arm 11 can be adjusted as shown in the figure. Figure 6 The hook moves within the range shown, quickly following the swaying of the ship to suppress the swing of the hook, thereby completing the motion compensation for the swaying of the ship and achieving the active anti-roll effect.

[0044] In summary, compared with the existing technology, the dynamic compensation mechanical arm mechanism of the marine ship crane of the present invention has the following advantages and beneficial effects: simple and flexible structure, rapid compensation movement response, large-scale motion compensation is achieved by driving the mechanical arm to rotate by the hydraulic cylinder, and the ability to cope with extreme sea conditions is stronger. It comprehensively improves the wave and wind resistance of the ship during sea surface operations, and can ensure the safety and efficiency of the crane's operation in harsh marine environments.

[0045] The above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. If the present invention is modified or replaced with equivalents without departing from the spirit and scope of the present invention, they should be included in the scope of protection of the claims of the present invention.

Claims

1. A dynamic compensation mechanical arm mechanism for a marine ship crane, characterized in that: include: A frame for connecting to a marine vessel crane; Left and right robotic arms symmetrically articulated with the frame; Two mechanical rods are respectively hinged to the left and right mechanical arms, a winch is fixed on one of the mechanical rods, a wire rope pulley is provided at the end of the mechanical rod fixing the winch, and the wire rope of the winch passes through the wire rope pulley and is connected to the hook; Two hydraulic cylinders fixed to the frame are used to drive one of the robotic arms to rotate; The monitoring unit is used to measure the rotation angle and speed of the winch to obtain the swing length of the wire rope and the current speed of the hook, and to measure the distance and lateral displacement of the hook relative to the equilibrium position; The controller is used to calculate the control quantity according to the data measured by the monitoring unit, obtain the hydraulic oil flow of the hydraulic cylinder, control the rotation of one of the mechanical arms, and drive the hook to move to suppress the swing of the hook.

2. The dynamic compensation mechanical arm mechanism of the marine ship crane according to claim 1, characterized in that: The control quantity calculated by the controller is: u 总 =u θ (t)+u α (t)+u 前馈 +u 预测 ; in: u 前馈 =K ff ·a(t)·Δt; u 预测 =K 预测 ·S·Δt; Where u θ (t) is the longitudinal control quantity, u α (t) is the lateral control quantity, u 前馈 is the compensation signal, u 预测 is the predictive control signal; t is the time variable, K pθ ,K iθ ,K dθ are the proportional, integral and differential coefficients of the longitudinal control loop, K pα ,K iα ,K dα are the proportional, integral, and differential coefficients of the lateral control loop; K 预测 is the prediction gain coefficient, e θ (t) is the longitudinal error, e α (t) is the lateral error, K ff is the feedforward gain coefficient, K 预测 is the prediction gain coefficient; S is the periodic wave model, Δt is the time difference; The two hydraulic cylinders are A and B, and their control signals are: in A =in 总 ·k; in B =in 总 ·(1-k); Where k is the distribution coefficient; The hydraulic oil flow of hydraulic cylinders A and B is: where k qA , K qB is the servo valve flow coefficient of hydraulic cylinders A and B, Δp A ,Δp B is the valve port pressure difference inside hydraulic cylinders A and B.

3. The dynamic compensation mechanical arm mechanism of the marine ship crane according to claim 2, characterized in that: in: e θ (t)=θ 目标 -θ 实际 ; e α (t)=a 目标 -a 实际 ; where θ 实际 and α 实际 are the longitudinal swing angle and lateral swing angle of the hook relative to the equilibrium position, L is the swing length of the wire rope, and X and Y are the distance and lateral displacement of the hook relative to the equilibrium position, respectively.

4. The dynamic compensation mechanical arm mechanism of the marine ship crane according to claim 2, characterized in that: in: Where L is the pendulum length of the wire rope, ω represents the speed of the periodic change of the wave, is the initial phase offset of the sine function, indicating the starting position of the wave on the time axis.

5. The dynamic compensation mechanical arm mechanism of the marine ship crane according to claim 1, characterized in that: One of the mechanical arms is connected to the frame via a plane bearing.

6. The dynamic compensation mechanical arm mechanism of the marine ship crane according to claim 4, characterized in that: The plane bearing is fixed by a pipe cap and a bolt group, and the relative position of one of the mechanical arms and the frame is fixed by a gasket.

7. The dynamic compensation mechanical arm mechanism of the marine ship crane according to claim 1, characterized in that: The monitoring unit includes a winch encoder and an ultrasonic sensor; the winch encoder measures the rotation angle and speed of the winch; the ultrasonic sensor is used to measure the distance and lateral displacement of the hook relative to the equilibrium position.

8. The dynamic compensation mechanical arm mechanism of the marine ship crane according to claim 1, characterized in that: Also features lighting.

Images