Magnetorheological technology-based anti-sway and energy recovery device for ship crane

Abstract

The application provides a ship-mounted crane swing damping and energy recovery device based on magneto-rheological technology, which comprises a composite magneto-rheological damper hydraulic cylinder, an accumulator and a hydraulic circuit, the composite magneto-rheological damper hydraulic cylinder is connected to a static platform through a hooke joint, the top of the piston rod of the composite magneto-rheological damper hydraulic cylinder is connected to a dynamic platform through a hooke joint, the static platform is connected to a crane boom head, a steel wire rope is drawn out from the crane boom head and connected to a load through a hook; the composite magneto-rheological damper hydraulic cylinder comprises a magneto-rheological damper part and a hydraulic cylinder part, wherein the hydraulic cylinder part is connected to the accumulator through the hydraulic circuit, the damper part is used for actively damping the swing of the load, at the same time, the gravitational potential energy in the swing process and the kinetic energy of the swing are recycled and stored in the accumulator. The application consumes the kinetic energy in the swing to achieve the effect of swing damping. The energy of the load is recycled and stored in the accumulator, which is energy-saving and environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of damping and energy recovery for marine cranes, and particularly to a device for damping and energy recovery for marine cranes based on magnetorheological technology. Background Technology

[0002] In recent years, with the rise of the shipping industry, marine cranes have played an indispensable role in cargo handling. However, in the marine environment, the hull is affected by wind, waves, and currents, causing the lifted load to sway, which can seriously affect operational efficiency and even personal safety. Therefore, research on reducing sway in marine crane lifting is of great significance. Currently available sway reduction technologies include mechanical and electronic control. Traditional sway reduction methods for marine crane telescopic sleeve structures involve controlling the number and placement of cables. While some achieve sway reduction, these are only passive and not well-suited for various working conditions. Active control sway reduction devices, such as those controlling the crane base or using multiple ropes to control the hook, require a large amount of energy and are not economically efficient. Furthermore, the kinetic and gravitational potential energy of the swaying load is not utilized. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a sway reduction and energy recovery device for marine cranes based on magnetorheological technology. This invention applies a designed composite magnetorheological damper hydraulic cylinder to a marine crane, enabling active sway reduction while simultaneously utilizing the gravitational potential energy and kinetic energy of the cargo. The technical means employed in this invention are as follows:

[0004] A marine crane sway reduction and energy recovery device based on magnetorheological technology includes a composite magnetorheological damper hydraulic cylinder, an accumulator, and a hydraulic circuit. The composite magnetorheological damper hydraulic cylinder is connected to a stationary platform via a Hooke joint, and the top of the piston rod of the composite magnetorheological damper hydraulic cylinder is connected to a moving platform via a Hooke joint. The stationary platform is connected to the crane boom head, and a wire rope is led out from the crane boom head and connected to the load via a hook. The composite magnetorheological damper hydraulic cylinder includes a magnetorheological damper part and a hydraulic cylinder part. The hydraulic cylinder part is connected to the accumulator via a hydraulic circuit. The damper part is used to actively reduce the sway of the load, and at the same time, recovers and utilizes the gravitational potential energy and kinetic energy of the sway during the swaying process, storing them in the accumulator.

[0005] Furthermore, four composite magnetorheological damper hydraulic cylinders are circumferentially distributed between the moving and stationary platforms. The moving and stationary platforms are connected by a hollow tube, which is connected to the stationary platform via a Hooke hinge. The Hooke hinge is a hollow structure for the steel wire rope to pass through. The bottom of the hollow tube is fixed to the top of the moving platform, and a sleeve is connected to the bottom of the moving platform. The steel wire rope is led out from the crane boom head, passes through the middle Hooke hinge of the stationary platform, and enters the sleeve between the two platforms and the sleeve under the moving platform. It is then connected to the load via a hook.

[0006] Furthermore, the magnetorheological damper cylinder is embedded inside the hydraulic cylinder, and the outer shell of the magnetorheological damper cylinder is connected to the inside of the hydraulic cylinder. The two are arranged in a coaxial straight line. The overall structure is spliced ​​and divided into two symmetrical parts, which are fixed by four bolts. Static sealing rings are installed at the joint of the two parts. For the left part, three annular grooves are opened at the contact point between the external hydraulic cylinder and the piston rod, which are, from the outside to the inside, a dustproof ring groove, a guide ring groove, and a sealing ring groove. Two grooves are opened at the contact point between the internal magnetorheological damper hydraulic cylinder and the piston rod, which are, from the outside to the inside, a guide ring groove and a sealing ring groove. For the right part, the grooves of the magnetorheological damper hydraulic cylinder are the same as those on the left side, and the external hydraulic cylinder does not need to be grooved. The external hydraulic pumps on both sides are respectively provided with channels for connecting hydraulic pipelines, and speed sensors are installed at the inlet and outlet of the piston rod of the entire device. The piston of the external hydraulic cylinder also has three grooves, which are used as guide ring grooves and oil scraper ring grooves.

[0007] Furthermore, the internal magnetorheological damper electromagnet core is machined into an I-shaped piston with a coil wound in the middle. The piston flange is 1mm away from the inner surface of the magnetorheological damper hydraulic cylinder, which is called the damping gap. This gap allows the magnetorheological fluid to flow when the piston rod moves relative to the composite magnetorheological damper hydraulic cylinder. The pistons of both hydraulic cylinders are connected to the same piston rod. From left to right, they are: the first piston of the outer hydraulic cylinder, the internal magnetorheological damper electromagnet core, and the second piston of the outer hydraulic cylinder. The initial state of the composite magnetorheological damper hydraulic cylinder during installation is that the electromagnet core of the piston rod is in the middle position of the magnetorheological damper.

[0008] Furthermore, a channel is opened in the middle of the piston rod, and a round hole is opened near the second piston. A rectangular hole is opened on the side of the right outer hydraulic cylinder. The wiring method of the entire composite magnetorheological damper hydraulic cylinder is as follows: the wire enters the channel of the piston rod through the round hole of the piston rod from the rectangular hole, then passes through the round hole on the magnetorheological damper electromagnet core and is wound around the middle of the piston. The wire then returns along the same path and exits through the rectangular hole. The wire inlet and outlet are connected to the control unit.

[0009] Furthermore, the space to the left of the first piston and the right of the second piston is filled with hydraulic oil, and the space to the built-in magnetorheological damper is filled with magnetorheological fluid.

[0010] Furthermore, the hydraulic circuit includes a sway-reducing hydraulic passage and an energy recovery circuit. The sway-reducing hydraulic passage is equipped with a two-position two-way solenoid directional valve and a safety valve. The energy recovery circuit includes a two-position two-way solenoid directional valve, a two-position four-way solenoid directional valve, a check valve, an oil tank, a filter, a hydraulic motor, and a hydraulic pump.

[0011] Furthermore, a displacement sensor is installed at the piston rod outlet of the composite magnetorheological damper hydraulic cylinder. The sensor inputs the motion signal of the piston rod relative to the hydraulic cylinder to the control unit. The control unit controls the energization and de-energization of the solenoid directional valve based on the sign of the product of the two vector signals, and simultaneously controls the energization and de-energization of the magnetorheological damper. The magnitude of the current input to the magnetorheological damper is adjusted by the control unit according to the relative motion speed. The direction of piston rod movement away from the magnetorheological damper hydraulic cylinder is defined as positive.

[0012] Furthermore, the output of the accumulator is connected to the heave compensation circuit of the semi-active marine crane.

[0013] This invention has the following advantages: As the crane is propelled by ocean waves, it sways with the ship's hull, and the load swings accordingly due to inertia. The device has four strokes during the swing, with the first and third strokes having the same effect, and the second and fourth strokes having a different effect. During the strokes with increased swing angles, the magnetorheological damper is energized, and the coil wound around the piston of the damper creates a closed magnetic circuit. The magnetorheological fluid flowing through the damping gap changes from a fluid state to a near-solid state under the influence of the magnetic field, hindering the flow of the magnetorheological fluid through the damping gap. This, in turn, hinders the movement of the piston rod relative to the magnetorheological damper cylinder, thereby absorbing the kinetic energy of the swinging load and achieving a sway reduction effect. By inputting different currents under different operating conditions, corresponding damping forces are output, enabling active damping of the swinging load and achieving a sway reduction effect by consuming the kinetic energy of the swing. With the stroke of the reduced swing angle, the magnetorheological damper is de-energized, recovering and utilizing the gravitational potential energy and kinetic energy of the load, storing them in the accumulator. The energy stored in the accumulator can be used to achieve the energy required for active and passive compensation in the heave compensation of the marine crane. Attached Figure Description

[0014] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a hydraulic schematic diagram of the marine crane anti-sway and energy recovery device based on magnetorheological technology of the present invention.

[0016] Figure 2 This is a schematic diagram of a composite magnetorheological damper hydraulic cylinder used in a marine crane.

[0017] Figure 3 This diagram shows the connection between the hydraulic cylinder of the composite magnetorheological damper and the dynamic and static platforms.

[0018] Figure 4 This is a schematic diagram of the hydraulic cylinder of the composite magnetorheological damper in this invention.

[0019] Figure 5 This is a cross-sectional view of the hydraulic cylinder of the composite magnetorheological damper in this invention.

[0020] In the diagram: 1.1 Filter; 1.2 Oil tank; 1.3 Two-position four-way solenoid directional valve; 1.4 Hydraulic pump; 1.5 Check valve; 1.6 Accumulator; 1.7 Two-position two-way solenoid directional valve; 1.8 Hydraulic motor; 1.9 External hydraulic pipeline of accumulator; 2. Composite magnetorheological damper hydraulic cylinder; 2.1 Piston rod; 2.1.1 Piston rod channel; 2.1.2 Circular hole; 2.2 First piston; 2.3 Second piston; 2.4 Electromagnetic core; 2.4.1 Electromagnetic core circular hole; 2.5 Left side shell; 2.5.1 Static sealing groove; 2.5.2 Hydraulic pipeline inlet; 2.5.3 Displacement sensor; 2.5.4 Hydraulic pipeline inlet; 2.5.6 Dustproof ring, guide ring, sealing ring groove; 2.5.7 Guide ring, sealing ring groove; 2.5.9 Bolt hole; 2.6 Right side housing; 2.6.1 Hydraulic pipeline inlet; 2.6.2 Hydraulic pipeline inlet; 2.6.3 Guide ring, sealing ring groove; 2.6.4 Rectangular through hole; 2.7 Hydraulic oil space; 2.8 Magnetorheological fluid space; 2.9 Hydraulic oil space; 3.1 Safety valve; 3.2 Two-position two-way solenoid directional valve; 4. Crane; 4.1 Heavy object; 4.2 Static platform; 4.3 Moving platform; 4.4 Sleeve; 4.5 Wire rope; 4.6 Hooke hinge. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0022] like Figure 1-5As shown in the figure, this invention discloses a sway reduction and energy recovery device for a marine crane based on magnetorheological technology, including a composite magnetorheological damper hydraulic cylinder 2, a hydraulic circuit 1, and an accumulator 1.6. The bottom end of the composite magnetorheological damper hydraulic cylinder 2 is connected to a stationary platform 4.2 via a Hooke hinge 4.6, and the top of the piston rod 2.1 of the composite magnetorheological damper hydraulic cylinder 2 is connected to a moving platform 4.3 via a Hooke hinge 4.6. Four composite magnetorheological damper hydraulic cylinders are distributed equidistantly in a circle between the two platforms. A sleeve 4.4 connects the two platforms; the upper part of the sleeve is connected to the stationary platform via a Hooke hinge, and the lower part is fixed to the moving platform, with a portion extending out. Each composite magnetorheological damper hydraulic cylinder is equipped with an independent hydraulic system. Wires, signal lines of speed sensors 2.5.3, and hydraulic lines are systematically distributed on the boom of the crane 4, and the hydraulic lines lead to various valves and the accumulator. This device, in conjunction with the moving platform, stationary platform, and telescopic sleeve device, is installed at the boom head of a marine crane. The accumulator can be installed near the deck crane.

[0023] The composite magnetorheological damper hydraulic cylinder 2 comprises: a piston rod 2.1; a piston rod channel 2.1.1; a circular hole 2.1.2; a first piston 2.2; a second piston 2.3; an electromagnet core 2.4; a circular hole in the electromagnet core 2.4.1; a left outer shell 2.5; a static sealing groove 2.5.1; a hydraulic pipeline inlet 2.5.2; a speed sensor 2.5.3; a hydraulic pipeline inlet 2.5.4; a dustproof ring, guide ring, and sealing ring groove 2.5.6; a guide ring and sealing ring groove 2.5.7; bolt holes 2.5.9; a right outer shell 2.6; a hydraulic pipeline inlet 2.6.1; a hydraulic pipeline inlet 2.6.2; a guide ring and sealing ring groove 2.6.3; a rectangular through hole 2.6.4; a hydraulic oil space 2.7; a magnetorheological fluid space 2.8; and a hydraulic oil space 2.9. The composite magnetorheological damper hydraulic cylinder 2 comprises a magnetorheological damper section and a hydraulic cylinder section. The magnetorheological damper cylinder is embedded inside the hydraulic cylinder, with the former's outer shell connected to the latter's interior. Both are arranged coaxially in a straight line. The overall structure is a spliced ​​design, divided into two symmetrical left and right parts, secured by four bolts. Static sealing rings are installed at the joints of the two parts. For the left part, three annular grooves are carved at the contact point between the external hydraulic cylinder and the piston rod: from the outside in, a dustproof ring groove, a guide ring groove, and a sealing ring groove. Two grooves are carved at the contact point between the internal magnetorheological damper hydraulic cylinder and the piston rod: from the outside in, a guide ring groove and a sealing ring groove. For the right part, the magnetorheological damper hydraulic cylinder has the same grooves as the left side, while the external hydraulic cylinder does not require grooves. The external hydraulic pumps on both sides have channels for connecting hydraulic pipelines, and displacement sensors are installed at the piston rod inlet and outlet of the entire device. The internal magnetorheological damper's electromagnetic core is machined into an I-shaped piston with a coil wound around it. The 1mm gap between the piston flange and the inner surface of the magnetorheological damper's hydraulic cylinder is called the damping gap, allowing the magnetorheological fluid to flow when the piston rod moves relative to the hydraulic cylinder. The pistons of both hydraulic cylinders are connected to the same piston rod, from left to right: the first piston of the outer hydraulic cylinder, the electromagnetic core of the internal magnetorheological damper, and the second piston of the outer hydraulic cylinder. The outer hydraulic cylinder piston also has three grooves carved out, serving as guide ring grooves and oil scraper ring grooves. The left outer casing 2.5 and the right outer casing 2.6 are connected by bolts at bolt holes 2.5.9. The piston rod 2.1 is sequentially connected to the first piston 2.2, the electromagnetic core 2.4, and the second piston 2.3. A channel and small holes are carved on the right side of the piston rod, and a small hole and a rectangular through hole 2.6.4 are carved at the electromagnetic core for passing wires. Grooves are carved on the heads of the first and second pistons for mounting dustproof rings, guide rings, and sealing rings 2.5.6. The housing of the hydraulic cylinder with built-in magnetorheological damper has a groove cut into the piston rod to house the guide ring and sealing ring 2.5.7. 2.8 is the magnetorheological fluid space, and 2.7 and 2.9 are the hydraulic oil spaces.

[0024] A channel 2.1.1 is carved out in the middle of the piston rod, and a round hole 2.1.2 is carved out near the second piston. A rectangular hole is carved out on the side of the right outer hydraulic cylinder. The wiring of the entire composite magnetorheological damper hydraulic cylinder is as follows: the wire enters the piston rod channel through the round hole in the piston rod from the rectangular hole, then passes through the round hole 2.4.1 on the magnetorheological damper electromagnet core and winds around the middle of the piston. The wire then returns along the same path and exits through the rectangular hole. The wire inlet and outlet are connected to the control unit. The hydraulic line outlet of the accumulator is connected to the required pipeline, such as in the heave compensation circuit of a semi-active marine crane. The hydraulic circuit is divided into two parts: one part is the path for sway reduction, i.e., hydraulic line inlets 2.5.4 and 2.6.2; the other part is the path for energy recovery, i.e., hydraulic line inlets 2.5.2 and 2.6.1.

[0025] The hydraulic circuit for sway reduction includes a two-position two-way solenoid directional valve 3.2 and a safety valve 3.1. The energy recovery circuit includes a two-position two-way solenoid directional valve 1.7, a two-position four-way solenoid directional valve 1.3, a check valve 1.5, an oil tank 1.2, a filter 1.1, a hydraulic motor 1.8, and a hydraulic pump 1.4.

[0026] A displacement sensor 2.5.3 is installed at the piston rod outlet of the composite magnetorheological damper hydraulic cylinder. The sensor inputs the motion signal (relative displacement and relative velocity) of the piston rod relative to the hydraulic cylinder to the control unit. The control unit controls the energization and de-energization of the solenoid directional valve based on the sign of the product of the two vector signals, and simultaneously controls the energization and de-energization of the magnetorheological damper. The magnitude of the current input to the magnetorheological damper is adjusted by the control unit based on the relative velocity. The direction of piston rod movement away from the magnetorheological damper hydraulic cylinder is defined as positive. Each composite magnetorheological damper hydraulic cylinder is equipped with an independent hydraulic system.

[0027] The wire rope is led out from the crane boom head, passes through the stationary platform 4.2, and is connected to the Hooke hinge 4.6 and the sleeve 4.4, and then connected to the hook to suspend the load 4.1.

[0028] The specific working process of this embodiment is as follows: the hydraulic cylinder of the composite magnetorheological damper has four strokes. Taking the first composite magnetorheological damper hydraulic cylinder as an example, the first stroke is the stroke in which the piston rod 2.1 moves to the right relative to the hydraulic cylinder, increasing the swing angle; the second stroke is the stroke in which the piston rod moves to the left relative to the hydraulic cylinder and returns to center, decreasing the swing angle; the third stroke is the stroke in which the piston rod moves to the left relative to the hydraulic cylinder, increasing the swing angle; and the fourth stroke is the stroke in which the piston rod moves to the right relative to the hydraulic cylinder and returns to center, decreasing the swing angle. The first and third strokes achieve the same effect, namely, reducing the swing angle; the second and fourth strokes achieve a different effect, namely, energy recovery. The position of the reversing valves 1.3 and 1.7 in the energy recovery circuit is determined according to the four strokes of the composite magnetorheological damper hydraulic cylinder. That is, the signal collected by the displacement sensor is used as the input to the control unit. The control unit calculates the velocity signal from the collected displacement signal, and the sign of the result obtained by multiplying the two vector signals controls the energization and de-energization of the reversing valve and the magnetorheological damper. At the same time, the control unit adjusts the input current of the magnetorheological damper according to the velocity signal.

[0029] Taking one of the composite magnetorheological damper hydraulic cylinders 2 as an example, assuming this is the first stroke, when the crane 4 is performing cargo handling operations, as the swing angle of the load 4.1 increases, the directional valve 3.2 of the hydraulic circuit's sway reduction circuit is in the open position, while the two-position two-way directional valve 1.7 of the energy recovery circuit and the two-position four-way directional valve 1.3 in this circuit are both in the closed position. The magnetorheological damper electromagnetic coil is energized. At this time, the hydraulic oil space on the left side of the first piston and the hydraulic oil space on the right side of the second piston in the composite magnetorheological damper hydraulic cylinder are connected. During the swing of the cargo, the movement of the wire rope 4.5 drives the platform 4.3 to swing, which in turn causes the piston rod 2.1 to move relative to the composite magnetorheological damper hydraulic cylinder. The displacement sensor 2.5.3 on the composite hydraulic cylinder transmits the speed signal to the control unit, and the control unit outputs a corresponding current to the electromagnetic coil. The closed magnetic field generated by the electromagnetic coil makes the magnetorheological fluid at the damping gap become a solid-like substance, causing the magnetorheological damper to output resistance, hindering the relative motion, and thus absorbing the kinetic energy of the load during swing, thereby achieving sway reduction. The control unit outputs different current magnitudes based on the time-varying signals transmitted by the speed sensor, and the damping force output by the magnetorheological damper also varies, thus achieving active sway reduction of heavy objects under different working conditions.

[0030] During the stroke in which the swing angle of the load decreases (let's call this the second stroke), the directional valve of the swing reduction circuit is in the off position, the two-position two-way directional valve of the energy recovery circuit is in the through position, and the two-position four-way directional valve of this circuit is in the off position. The hydraulic oil on the left side of the first piston flows back to the right side of the second piston through the check valve to the hydraulic motor 1.8. The hydraulic oil spaces on both sides are the same, and the whole can be regarded as an oil tank. The hydraulic motor drives the hydraulic pump 1.4 to pump the hydraulic oil in the hydraulic tank into the accumulator 1.6. The hydraulic pipeline outlet of the accumulator is connected to the pipeline that needs to be used, such as in the heave compensation circuit of a semi-active marine crane. The hydraulic oil in the accumulator is discharged from 1.9 to supply the energy required for the semi-active heave compensation of the marine crane.

[0031] During the third stroke, the valve status of the hydraulic circuit and the status of the magnetorheological damper circuit are the same as those during the first stroke.

[0032] During the fourth stroke, the magnetorheological damper is de-energized, the sway reduction circuit reversing valve is in the open position, the two-position two-way reversing valve of the energy recovery circuit is in the open position, and the two-position four-way reversing valve is in the open position. The hydraulic oil on the right side of the second piston flows back to the left side of the first piston through the check valve and hydraulic motor under the action of the piston. The hydraulic pump pumps the hydraulic oil in the tank into the accumulator under the drive of the hydraulic motor, and then the principle continues to the second stroke.

[0033] The entire process enables the crane to actively reduce its sway and to reuse the gravitational potential energy and kinetic energy of the load in real time during the swing process.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for reducing sway and recovering energy in a marine crane based on magnetorheological technology, characterized in that, The system includes a composite magnetorheological damper hydraulic cylinder, an accumulator, and a hydraulic circuit. The composite magnetorheological damper hydraulic cylinder is connected to a stationary platform via a Hooke joint, and the top of the piston rod of the composite magnetorheological damper hydraulic cylinder is connected to a moving platform via a Hooke joint. The stationary platform is connected to the crane boom head, and a wire rope is led out from the crane boom head and connected to the load via a hook. The composite magnetorheological damper hydraulic cylinder includes a magnetorheological damper part and a hydraulic cylinder part. The hydraulic cylinder part is connected to the accumulator via a hydraulic circuit. The damper part is used to actively reduce the swaying of the heavy object and simultaneously recover and utilize the gravitational potential energy and kinetic energy of the swaying process, storing them in the accumulator. The magnetorheological damper cylinder is embedded inside the hydraulic cylinder, and the outer shell of the magnetorheological damper cylinder is connected to the inside of the hydraulic cylinder. The two are arranged in a coaxial straight line. The overall structure is spliced ​​and divided into two symmetrical parts, which are fixed by four bolts. Static sealing rings are installed at the joint of the two parts. For the left part, three annular grooves are opened at the contact point between the external hydraulic cylinder and the piston rod, which are, from the outside to the inside, a dustproof ring groove, a guide ring groove, and a sealing ring groove. Two grooves are opened at the contact point between the internal magnetorheological damper hydraulic cylinder and the piston rod, which are, from the outside to the inside, a guide ring groove and a sealing ring groove. For the right part, the grooves of the magnetorheological damper hydraulic cylinder are the same as those on the left side, and the external hydraulic cylinder does not need to be grooved. The external hydraulic pumps on both sides are respectively provided with channels for connecting hydraulic pipelines, and speed sensors are installed at the inlet and outlet of the piston rod of the entire device. The piston of the external hydraulic cylinder also has three grooves, which are used as guide ring grooves and oil scraper ring grooves. The internal magnetorheological damper's electromagnetic core is machined into an I-shaped piston with a coil wound in the middle. The 1mm gap between the piston flange and the inner surface of the magnetorheological damper's hydraulic cylinder is called the damping gap, which allows the magnetorheological fluid to flow when the piston rod moves relative to the composite magnetorheological damper's hydraulic cylinder. The pistons of both hydraulic cylinders are connected to the same piston rod. From left to right, they are: the first piston of the outer hydraulic cylinder, the electromagnetic core of the internal magnetorheological damper, and the second piston of the outer hydraulic cylinder. The initial state of the composite magnetorheological damper's hydraulic cylinder during installation is that the electromagnetic core of the piston rod is in the middle position of the magnetorheological damper. A channel is opened in the middle of the piston rod, and a round hole is opened near the second piston. A rectangular hole is opened on the side of the right outer hydraulic cylinder. The wiring method of the entire composite magnetorheological damper hydraulic cylinder is as follows: the wire enters the channel of the piston rod through the round hole of the piston rod from the rectangular hole, and then passes through the round hole on the magnetorheological damper electromagnet core and is wound in the middle of the piston. The wire then returns along the same path and exits through the rectangular hole. The wire inlet and outlet are connected to the control unit. The space to the left of the first piston and the right of the second piston is filled with hydraulic oil, and the space for the built-in magnetorheological damper is filled with magnetorheological fluid.

2. The marine crane anti-sway and energy recovery device based on magnetorheological technology according to claim 1, characterized in that, Four composite magnetorheological damper hydraulic cylinders are circumferentially distributed between the moving and stationary platforms. The moving and stationary platforms are connected by a hollow tube, which is connected to the stationary platform by a Hooke hinge. The Hooke hinge is a hollow structure for the steel wire rope to pass through. The bottom of the hollow tube is fixed to the top of the moving platform, and a sleeve is connected to the bottom of the moving platform. The steel wire rope is led out from the crane boom head, passes through the middle Hooke hinge of the stationary platform, and enters the sleeve between the two platforms and the sleeve under the moving platform. The load is connected to the hook.

3. The marine crane anti-sway and energy recovery device based on magnetorheological technology according to claim 1, characterized in that, The hydraulic circuit includes a sway-reducing hydraulic passage and an energy recovery circuit. The sway-reducing hydraulic passage is equipped with a two-position two-way solenoid directional valve and a safety valve. The energy recovery circuit includes a two-position two-way solenoid directional valve, a two-position four-way solenoid directional valve, a check valve, an oil tank, a filter, a hydraulic motor, and a hydraulic pump.

4. The marine crane anti-sway and energy recovery device based on magnetorheological technology according to claim 3, characterized in that, A displacement sensor is installed at the piston rod outlet of the hydraulic cylinder of the composite magnetorheological damper. The sensor inputs the motion signal of the piston rod relative to the hydraulic cylinder to the control unit. The control unit controls the energization and de-energization of the solenoid directional valve based on the sign of the product of the two vector signals, and at the same time controls the energization and de-energization of the magnetorheological damper. The magnitude of the current input to the magnetorheological damper is adjusted by the control unit according to the relative motion speed. The direction of piston rod movement away from the hydraulic cylinder of the magnetorheological damper is set as positive.

5. The marine crane anti-sway and energy recovery device based on magnetorheological technology according to claim 1, characterized in that, The output of the accumulator is connected to the heave compensation circuit of the semi-active marine crane.

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