Ocean winch with wave compensation function and compensation method

Abstract

The application discloses a marine winch with a wave compensation function and a compensation method, and relates to the technical field of winches. A first reduction motor is connected with a left winch, a second reduction motor is connected with a right winch, a third reduction motor is connected with a cable storage reel, and a fourth reduction motor is connected with a cable arranging device. When a load end cable is retracted, the cable enters a guide wheel through a cable guide, passes through a first rope groove in the lower part of the right winch horizontally, is wound around the first rope groove of the left winch in a half circle, and then returns to the upper part of the second rope groove of the right winch from the upper part of the first rope groove of the left winch. In this way, each rope groove is wound with a cable, and finally, the cable is discharged from the lower part of the last rope groove of the left winch, vertically enters the cable storage reel through the cable arranging device, and is fixed. The left and right winches are horizontally installed. When the cable is retracted and discharged, the cable is retracted and discharged in a downward manner. The application has the beneficial effects that: during the cable retraction and discharge process, the system automatically adjusts the speed according to the tension change, effectively protects the cable, can adapt to the retraction and discharge of a large-capacity cable, and has high reliability.

Description

Technical Field

[0001] This invention relates to the field of winch technology, and in particular to a marine winch with wave compensation function, its control device, and wave compensation method. Background Technology

[0002] Marine winches can be used for the underwater mooring, lowering, and retrieval of equipment such as unpowered probes and submersibles in deep-sea operations. During marine winch operations, the heave caused by waves affects the vessel's attitude, resulting in constant changes in the tension of the winch cable. This phenomenon easily leads to cable fatigue, affecting its service life, and large, drastic tension changes can cause cable breakage, which can easily damage the equipment and threaten the lives of operators.

[0003] Existing wave compensation technology is generally applied to marine cranes. The most significant difference between deep-sea operation marine winches and ordinary marine cranes is that the cables are much longer, often several thousand meters or even tens of thousands of meters. Marine cranes, on the other hand, have shorter cables and can use a single drum to handle both lifting and cable storage. Therefore, the mechanical components of marine winches are quite different from those of marine cranes. Currently, commonly used wave compensation methods are basically lagging and lack motion prediction capabilities. They are passive wave compensation methods, which are more likely to break the cable when the ship is sinking violently.

[0004] Because equipment for deep-sea operations is often expensive and of great scientific value, the safety design of marine winches is particularly important. A key challenge in marine winch design is how to simultaneously provide wave compensation capabilities while deploying and retrieving large-capacity cables. Summary of the Invention

[0005] The purpose of this invention is to address the existing technical problems and shortcomings by providing a marine winch with wave compensation function and a compensation method.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A marine winch with wave compensation function comprises a first geared motor connected to the left winch, a second geared motor connected to the right winch, a third geared motor connected to the cable storage drum, and a fourth geared motor connected to the cable guide. When the cable at the load end retracts, it enters the guide wheel through the cable guide, passes horizontally through the first rope groove at the bottom of the right winch, winds half a turn around the first rope groove of the left winch, then returns from the top of the first rope groove of the left winch to the top of the second rope groove of the right winch, and so on, with the cable wound around each rope groove. Finally, the cable exits from the bottom of the last rope groove of the left winch, passes through the cable guide, and vertically enters the cable storage drum and is fixed. The left and right winches are installed horizontally. The cable enters and exits the left and right winches in a bottom-in, bottom-out manner.

[0008] Preferably, the cable guide includes a cable laying screw and a cable laying guide wheel. A fourth reduction motor drives the cable laying screw to rotate. A slider is fixed on the cable laying screw, and the cable laying guide wheel is rotatably mounted on the slider.

[0009] Preferably, the system further includes an operating unit, a pin force sensor, a displacement sensor, an MRU sensor, a control unit, a switch, a frequency converter, an encoder, and a braking resistor. The output terminals of the operating unit, the pin force sensor, and the displacement sensor are respectively connected to the control unit; the control unit is connected to the switch; the switch is respectively connected to the first to fourth frequency converters and the MRU sensor; the first to fourth frequency converters are respectively connected to the first to fourth encoders; the first to third frequency converters are also respectively connected to the first to third braking resistors; the MRU sensor is installed on the ship's deck at the guide wheel, the displacement sensor is coaxially installed with the guide wheel, and the pin force sensor is installed on the guide wheel shaft.

[0010] Preferably, the control unit has a DC 24V switch input module, a 0~20mA current input module, and a communication module; the operation unit outputs a DC 24V switch signal; the pin force sensor and displacement sensor both output a 0~20mA current signal; and the first to fourth frequency converters all have built-in gateway cards and encoder cards.

[0011] Preferably, the MRU sensor outputs ship roll, pitch, speed, and acceleration information via communication signals.

[0012] Preferably, the first frequency converter corresponding to the first geared motor is set to speed servo mode, and the second frequency converter corresponding to the second geared motor is set to torque servo mode, so that the right winch always rotates with the left winch under the action of the cable, keeping their linear speeds synchronized; the third frequency converter corresponding to the third geared motor is set to torque servo mode, and the torque is always set to the direction of cable winding, and the torque is much smaller than the combined torque of the first and second geared motors; the fourth frequency converter corresponding to the fourth geared motor is set to speed servo mode, ensuring that when the cable storage drum rotates one revolution, the cable winding guide wheel driven by the cable winding screw moves a distance of one cable diameter. At the same time, the control unit obtains the signal of the fourth encoder through communication with the fourth frequency converter, calculates the displacement of the cable winding guide wheel in real time, and performs automatic reversal at the end of the cable winding screw.

[0013] A wave compensation method for an ocean winch includes the following steps: When the winch is hovering with a load: The control unit continuously collects ship roll cycle data multiple times via MRU sensors, averages the data, and calculates information such as ship roll, pitch, velocity, and acceleration. Based on the current ship attitude data, it calculates the required compensation displacement and acceleration for the winch system. When the ship's attitude is generally in an ascending phase, the winch system releases the cable with the predicted compensation acceleration, and the compensation displacement is the amount calculated in the previous cycle. The displacement feedback value is detected by a displacement sensor. When the ship's attitude is generally in a descending phase, the winch system retrieves the cable with the predicted compensation acceleration, and the compensation displacement is the amount calculated in the previous cycle. The displacement feedback value is detected by a displacement sensor.

[0014] When the winch is winding up the cable: if the actual linear speed of the cable is less than the set speed but the actual tension is greater than the maximum set tension, the cable will decelerate; if the actual tension equals the maximum set tension when the linear speed decreases to a non-zero value, the cable will maintain that linear speed; if the actual tension is still greater than the maximum set tension when the linear speed decreases to zero, an alarm will sound and manual operation will be required; if the linear speed is less than the set speed and the actual tension is less than the minimum set tension, the cable will accelerate; if the linear speed increases to a certain value but does not exceed the set speed, and the actual tension is greater than the minimum set tension but less than the maximum set tension, the linear speed will continue to increase; if the linear speed increases to a certain value but is less than or equal to the set speed, and the actual tension equals the maximum set tension, the cable will maintain that linear speed; if the linear speed increases to a value greater than the set speed, an alarm will sound and manual operation will be required.

[0015] When the winch releases the cable: if the actual linear speed of the cable is less than the set speed but the actual tension is greater than the maximum set tension, the speed will increase; if the linear speed increases to a certain value but does not exceed the set speed, and the actual tension equals the maximum set tension, the speed will be maintained; if the linear speed increases to the set speed but the actual tension is still greater than the maximum set tension, an alarm will sound and manual operation will be required; if the linear speed is less than the set speed and the actual tension is less than the minimum set tension, the speed will decrease; if the linear speed decreases to a non-zero value and the actual tension equals the minimum set tension, the speed will be maintained; if the linear speed decreases to 0 and the actual tension is less than the minimum set tension, an alarm will sound and manual operation will be required.

[0016] The beneficial effects of this invention are:

[0017] (1) The system adopts a separate function for dragging load and storing cable, which can adapt to the winding and unwinding of large-capacity cables;

[0018] (2) The winch adopts a dual-drive redundant design, which ensures high reliability;

[0019] (3) When hovering with a load, the system has the function of predicting the ship's deep motion and performing wave compensation in advance;

[0020] (4) During the cable winding and unwinding process, the system automatically adjusts the speed according to the tension change to effectively protect the cable. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a marine winch with wave compensation function according to the present invention;

[0022] Figure 2 This is a schematic diagram of the control device for a marine winch with wave compensation function according to the present invention.

[0023] The components are: 1-Third geared motor, 2-Cable storage drum, 3-Fourth geared motor, 4-Cable guide wheel, 5-Cable lead screw, 6-First geared motor, 7-Left winch, 8-Second geared motor, 9-Right winch, 10-Cable, 11-Guide wheel, 12-Cable guide, 13-Operating unit, 14-Pin force sensor, 15-Displacement sensor, 16-Control unit, 16-1-Switch input module, 16-2-Current input module, 16-3-Communication module, 17-MRU sensor, 18-Switch, 19-First frequency converter, 20-First encoder, 21-First braking resistor, 22-Second frequency converter, 23-Second encoder, 24-Second braking resistor, 25-Third frequency converter, 26-Third encoder, 27-Third braking resistor, 28-Fourth frequency converter, 29-Fourth encoder. Detailed Implementation

[0024] The technical solution of the present invention will be further described in detail below using the tension attenuation winch of a certain aerial recovery device as an example, in conjunction with the accompanying drawings.

[0025] like Figure 1The marine winch with wave compensation function shown consists of a first geared motor 6, a second geared motor 8, a third geared motor 1, a fourth geared motor 3, a left winch 7, a right winch 9, a cable storage drum 2, a cable laying screw 5, a cable laying guide wheel 4, a guide wheel 11, a cable guide 12, and a cable 10. The first geared motor 6 is connected to the left winch 7, the second geared motor 8 is connected to the right winch 9, the third geared motor 1 is connected to the cable storage drum 2, and the fourth geared motor 3 is connected to the cable laying screw 5. A slider is fixed on the cable laying screw 5, and the cable laying guide wheel 4 is rotatably mounted on the slider. The load-end cable 10 enters the guide wheel 11 through the cable guide 12, passes horizontally through the first rope groove at the bottom of the right winch 9, wraps half a turn around the first rope groove of the left winch 7, then returns from the top of the first rope groove of the left winch 7 to the top of the second rope groove of the right winch 9, and so on, with the cable 10 wrapped around each rope groove. Finally, the cable exits from the bottom of the last rope groove of the left winch 7, passes through the cable guide wheel 4, and vertically enters the cable storage drum 2 and is fixed. The angle between the cable 10 entering and exiting the guide wheel 11 after passing through the cable guide 12 is 90 degrees; the left winch 7 and the right winch 9 are installed horizontally; the cable 10 enters and exits the left winch 7 and the right winch 9 in a bottom-in, bottom-out manner.

[0026] like Figure 2 The diagram shows the configuration of a control device for a marine winch with wave compensation function, including an operation unit 13, a pin force sensor 14, a displacement sensor 15, a control unit 16, an MRU sensor 17, a switch 18, first to fourth frequency converters 19, 22, 25, 28, first to fourth encoders 20, 23, 26, 29, and first to third braking resistors 21, 24, 27. The output terminals of the operation unit 13, the pin force sensor 14, and the displacement sensor 15 are respectively connected to the control unit 16; the control unit 16 is connected to the switch 18; the switch 18 is respectively connected to the first to fourth frequency converters 19, 22, 25, 28, and the MRU sensor 17; the first to fourth frequency converters 19, 22, 25, and 28 are respectively connected to the first to fourth encoders 20, 23, 26, and 29; the first to third frequency converters 19, 22, and 25 are also respectively connected to the first to third braking resistors 21, 24, and 27; the MRU sensor 17 is installed on the ship's deck at the guide wheel 11; the displacement sensor 15 is coaxially installed with the guide wheel 11; and the pin force sensor 14 is installed on the shaft of the guide wheel 11. The MRU sensor 17 can output information such as ship roll, pitch, speed, and acceleration.

[0027] The control unit 16 has a DC 24V switch input module 16-1, a 0~20mA current input module 16-2, and a communication module 16-3; the operation unit 13 outputs a DC 24V switch signal; the pin force sensor 14 and the displacement sensor 15 both output a 0~20mA current signal; the first to fourth frequency converters 19, 22, 25, and 28 each have a built-in gateway card and encoder card, and the first to fourth frequency converters 19, 22, 25, and 28 are respectively connected to the first geared motor 6 to the fourth geared motor 3; the first geared motor 6 to the fourth geared motor 3 correspond to the first to fourth encoders 20, 23, 26, and 29 respectively; the MRU sensor 17 outputs a communication signal.

[0028] The system described above has three wave compensation modes: hovering with load, cable retraction, and cable deployment.

[0029] When hovering with a load: The control unit 16 samples the ship's rolling cycle data five times consecutively via the MRU sensor 17, averages the data, and calculates information such as the ship's roll, pitch, speed, and acceleration. Based on the current ship attitude data, it calculates the required acceleration for the winch system to compensate for the displacement. When the ship's overall attitude is in an ascending phase, the winch system releases the cable with the predicted acceleration, and the displacement is the compensation calculated in the previous cycle. The displacement feedback value is detected by the displacement sensor 15. When the ship's overall attitude is in a descending phase, the winch system retrieves the cable with the predicted acceleration, and the displacement is the compensation calculated in the previous cycle. The displacement feedback value is detected by the displacement sensor 15.

[0030] When reeling in the cable: If the actual linear speed of cable 10 is less than the set speed but the actual tension is greater than the maximum set tension, then decelerate; if the actual tension equals the maximum set tension when the linear speed decreases to a non-zero value, then maintain the linear speed; if the actual tension is still greater than the maximum set tension when the linear speed decreases to zero, then an alarm is triggered, requiring manual operation. If the linear speed is less than the set speed and the actual tension is less than the minimum set tension, then accelerate; if the linear speed increases to a certain value but does not exceed the set speed, and the actual tension is greater than the minimum set tension but less than the maximum set tension, then the linear speed continues to increase; if the linear speed increases to a certain value but is less than or equal to the set speed, and the actual tension equals the maximum set tension, then maintain the linear speed; if the linear speed increases to a value greater than the set speed, then an alarm is triggered, requiring manual operation.

[0031] During cable laying: When the actual linear speed of cable 10 is less than the set speed but the actual tension is greater than the maximum set tension, the cable accelerates; if the linear speed increases to a certain value but does not exceed the set speed, and the actual tension equals the maximum set tension, the cable maintains that speed; if the linear speed increases to the set speed but the actual tension is still greater than the maximum set tension, an alarm is triggered, requiring manual operation. When the linear speed is less than the set speed and the actual tension is less than the minimum set tension, the cable decelerates; if the linear speed decreases to a non-zero value and the actual tension equals the minimum set tension, the cable maintains that speed; if the linear speed decreases to 0 and the actual tension is less than the minimum set tension, an alarm is triggered, requiring manual operation.

[0032] The first inverter 19 corresponding to the first geared motor 6 is set to speed servo mode, and the second inverter 22 corresponding to the second geared motor 8 is set to torque servo mode, so that the right winch 9 always follows the left winch 7 under the action of the cable, keeping their linear speeds synchronized; the third inverter 25 corresponding to the third geared motor 1 is set to torque servo mode, and the torque is always set to the direction of cable winding, and the torque is much smaller than the combined torque of the first geared motor 6 and the second geared motor 8; the fourth inverter 22 corresponding to the fourth geared motor 3 is set to speed servo mode, ensuring that when the cable storage drum 2 rotates one revolution, the cable guide wheel 4 driven by the cable winding screw 5 moves a distance of one cable diameter. At the same time, the control unit 16 obtains the signal of the fourth encoder 29 through communication with the fourth inverter 28, calculates the displacement of the cable guide wheel 4 in real time, and performs automatic reversal at the end of the cable winding screw 5.

[0033] When reeling in the cable, the left winch 7 and right winch 9 work together under the drive of the first reduction motor 6 and the second reduction motor 8, dragging the load together through the cable 10. When releasing the cable, when the load is small, the left winch 7 and right winch 9 actively release the cable, while the cable storage drum 2 is dragged backward. The third reduction motor 1 is in generator mode, and the energy is released through the third braking resistor 27. When the load is large, the left winch 7 and right winch 9 are passively released under the drag of the load, and the cable storage drum 2 is also dragged backward. At this time, the first reduction motor 6 to the third reduction motor 1 are all in generator mode, and the energy is released through the first braking resistor 21 to the third braking resistor 27 respectively.

[0034] The force sensor 14 measures force in the same direction as the angle bisector of the guide wheel 11 as it enters or exits the cable, which is 45 degrees. Therefore, the magnitude of the force it measures is the actual tension of the cable 10. The displacement sensor 15 is coaxially mounted with the guide wheel 11, and the measured displacement is the product of the number of rotations of the guide wheel 11 and the equivalent circumference of the cable 10 after it is wound around it. Both the pin force sensor 14 and the displacement sensor 15 use current signal output, which can improve the signal transmission distance and anti-interference ability.

[0035] The above description is merely a preferred embodiment of the present invention. Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, any person skilled in the art can make various corresponding equivalent changes and modifications based on the present invention, all of which should fall within the protection scope of the appended claims.

Claims

1. A compensation method of a marine winch with wave compensation function, the marine winch is composed of a first reduction motor, a second reduction motor, a third reduction motor, a fourth reduction motor, a left winch, a right winch, a cable storage reel, a cable arranging screw rod, a cable arranging guide wheel, a guide wheel, a cable guide and a cable, wherein the first reduction motor is connected to the left winch, the second reduction motor is connected to the right winch, the third reduction motor is connected to the cable storage reel, the fourth reduction motor is connected to the cable arranging screw rod, a sliding block is fixed on the cable arranging screw rod, and the cable arranging guide wheel is rotatably installed on the sliding block; the load end cable enters the guide wheel through the cable guide, passes through the first rope groove at the lower part of the right winch horizontally, is wound around the first rope groove of the left winch by half, and then returns to the upper part of the second rope groove of the right winch from the upper part of the first rope groove of the left winch, and so on, each rope groove is wound with the cable, and finally the cable is discharged from the lower part of the last rope groove of the left winch, vertically enters the cable storage reel through the cable arranging guide wheel, and is fixed; the angle between the cable entering and exiting the guide wheel through the cable guide is 90 degrees; the left winch and the right winch are installed in a horizontal lying type; the cable enters and exits the left winch and the right winch in a down-in and down-out manner, characterized in that, When the winch is in load suspension: the control unit collects ship swing cycle data through the MRU sensor for several times continuously, and calculates the ship roll, pitch amplitude, speed and acceleration information after averaging, and converts them into the compensation displacement and acceleration required by the winch system according to the current ship attitude data. When the overall ship attitude is in the rising period, the winch system releases the cable with the predicted compensation acceleration, the compensation displacement is the compensation amount calculated in the previous cycle, and the displacement feedback value is detected by the displacement sensor; when the overall ship attitude is in the falling period, the winch system takes up the cable with the predicted compensation acceleration, the compensation displacement is the compensation amount calculated in the previous cycle, and the displacement feedback value is detected by the displacement sensor; When the winch is taking up the cable: when the actual line speed of the cable is less than the set speed but the actual tension is greater than the maximum set tension, the cable speed is controlled to decrease; if the line speed decreases to a certain non-zero value and the actual tension is equal to the maximum set tension, the line speed is kept running; if the line speed decreases to 0 and the actual tension is still greater than the maximum set tension, an alarm is given and manual operation is required; When the line speed is less than the set speed and the actual tension is less than the minimum set tension, the speed is controlled to increase; if the line speed increases to a certain value but does not exceed the set speed, the actual tension is greater than the minimum set tension but less than the maximum set tension, and the line speed continues to increase; if the line speed increases to a certain value but is less than or equal to the set speed, the actual tension is equal to the maximum set tension, and the line speed is kept running; if the line speed increases to be greater than the set speed, an alarm is given and manual operation is required; When the winch is taking up the cable: when the actual line speed of the cable is less than the set speed but the actual tension is greater than the maximum set tension, the cable speed is controlled to decrease; if the line speed decreases to a certain non-zero value and the actual tension is equal to the maximum set tension, the line speed is kept running; if the line speed decreases to 0 and the actual tension is still greater than the maximum set tension, an alarm is given and manual operation is required; When the line speed is less than the set speed and the actual tension is less than the minimum set tension, the speed is controlled to increase; if the line speed increases to a certain value but does not exceed the set speed, the actual tension is greater than the minimum set tension but less than the maximum set tension, and the line speed continues to increase; if the line speed increases to a certain value but is less than or equal to the set speed, the actual tension is equal to the maximum set tension, and the line speed is kept running; if the line speed increases to be greater than the set speed, an alarm is given and manual operation is required; The first frequency converter corresponding to the first speed reducer is set to speed servo mode, the second frequency converter corresponding to the second speed reducer is set to torque servo mode, so that the right winch always follows the left winch under the action of the cable, keeping the line speed of the two synchronous; the third frequency converter corresponding to the third speed reducer is set to torque servo mode, and the torque is always set to the movement direction of taking up the cable, and the torque is much smaller than the combined torque of the first speed reducer and the second speed reducer; the fourth frequency converter corresponding to the fourth speed reducer is set to speed servo mode, to ensure that the cable discharge guide wheel moved by the cable discharge lead screw moves a distance of one cable diameter when the cable storage drum rotates one circle, and the control unit obtains the signal of the fourth encoder through communication with the fourth frequency converter to calculate the displacement of the cable discharge guide wheel in real time, and automatically reverses at the end of the cable discharge lead screw. When the cable is taken up, the left winch and the right winch jointly output power under the drive of the first and second reduction motors, and drag the load together through the cable; when the cable is put out, when the load is small, the left winch and the right winch actively put out the cable, while the cable storage reel is reversely dragged, the third reduction motor is in the state of power generation, and the energy is released through the third braking resistor; when the load is large, the left winch and the right winch passively put out the cable under the drag of the load, and the cable storage reel is also reversely dragged, at this time, the first reduction motor to the third reduction motor are all in the state of power generation, and the energy is released through the first braking resistor to the third braking resistor respectively; the force sensor of the pin shaft measures the force direction consistent with the angle bisector of the entry and exit of the guide wheel, which is 45 degrees, so the force size measured is the actual tension of the cable times; the displacement sensor is coaxially installed with the guide wheel, and the measured displacement is the product of the rotation number of the guide wheel and the equivalent circumference after winding the cable.

2. The compensation method of the marine winch with the wave compensation function according to claim 1, characterized in that, The marine winch with wave compensation function, first reduction motor is connected with left winch, second reduction motor is connected with right winch, third reduction motor is connected with cable storage reel, fourth reduction motor is connected with cable arranging device; when the load end cable is contracted, it enters the guide wheel through the cable guide, horizontally passes through the first rope groove under the right winch, is wound around the first rope groove of the left winch by half, and then returns to the upper part of the second rope groove of the right winch from the upper part of the first rope groove of the left winch, and so on, each rope groove is wound with the cable, and finally the cable is discharged from the lower part of the last rope groove of the left winch, vertically enters the cable storage reel through the cable arranging device and is fixed; the left and right winches are horizontally installed; the cable is in and out of the left and right winches in the way of going in and out from below.

3. The compensation method of the ocean winch with the wave compensation function according to claim 2, characterized in that, The cable guide includes a cable arranging screw rod and a cable arranging guide wheel, the fourth reduction motor drives the cable arranging screw rod to rotate, the cable arranging screw rod is fixed with a sliding block, and the cable arranging guide wheel is rotatably installed on the sliding block.

4. The compensation method of the ocean winch with the wave compensation function according to claim 3, characterized in that, It also includes an operation unit, a pin shaft force sensor, a displacement sensor, an MRU sensor, a control unit, a switch, a frequency converter, an encoder and a brake resistor, the frequency converter includes first to fourth frequency converters, the encoder includes first to fourth encoders, and the brake resistor includes first to third brake resistors; the output ends of the operation unit, the pin shaft force sensor and the displacement sensor are connected with the control unit respectively; the control unit is connected with the switch; the switch is connected with the first to fourth frequency converters and the MRU sensor respectively; the first to fourth frequency converters are connected with the first to fourth encoders respectively; the first to third frequency converters are also connected with the first to third brake resistors respectively; the MRU sensor is installed on the ship deck at the guide wheel, the displacement sensor is coaxially installed with the guide wheel, and the pin shaft force sensor is installed on the guide wheel shaft.

5. The compensation method of the marine winch with the wave compensation function according to claim 4, characterized in that, The control unit has a direct current 24V switching value input module, a 0~20mA current value input module and a communication module; the operation unit outputs a direct current 24V switching value signal; the pin shaft force sensor and the displacement sensor both output a 0~20mA current value signal; the first to fourth frequency converters both have built-in gateway cards and encoder cards.

6. The compensation method of the ocean winch with the wave compensation function according to claim 5, characterized in that, The MRU sensor outputs ship roll, pitch, speed and acceleration information in the form of communication signals. The MRU sensor outputs ship roll, pitch, speed and acceleration information in the form of communication signals.

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