Torque compensation method of AHC crane

Abstract

A torque compensation method of an AHC crane is used for compensating additional torque generated by the AHC crane in a dynamic environment due to movement of a suspension arm, the crane comprises a crane body and the suspension arm which are connected, the suspension arm comprises a main arm and a folding arm, and a main hook assembly and an auxiliary hook assembly are arranged on the suspension arm; the auxiliary hook assembly comprises an auxiliary winch arranged on the main arm, an auxiliary pulley block arranged at the front end of the folding arm and an auxiliary fixed pulley arranged between the auxiliary winch and the auxiliary pulley block; a force transducer is arranged at the auxiliary fixed pulley, a correction program is arranged in the force transducer at the auxiliary fixed pulley, and the correction program can be used for correcting data measured by the force transducer in real time by combining the swinging angles of the folding arm and the main arm, so that the data transmitted to a control system by the force transducer cannot be influenced by the swinging of the suspension arm; the overall weight of the crane is reduced, the stability of the ship body is improved, and the use cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of crane technology, and specifically to a torque compensation method for an AHC crane. Background Technology

[0002] AHC cranes are primarily used in offshore resource development, such as oil and gas and wind power, as well as underwater equipment installation and recovery operations. They are commonly used on offshore vessels and deep-sea drilling platforms. Typically, an AHC crane's boom has a main hook and an auxiliary hook. The main hook is used to lift heavy objects from the seabed, while the auxiliary hook is used to lift cargo or personnel from the ship or platform. The main hook is pulled by a main winch, while the auxiliary hook is pulled by an auxiliary winch, resulting in different wire rope paths for the main and auxiliary hooks. Therefore, fixed pulleys are usually installed at the force-measuring and extinguishing points of both the main and auxiliary hook wire rope paths. Force sensors located at these extinguishing points measure the tension of the wire rope at the fixed pulley, unaffected by boom swaying. This allows for more accurate force data transmission to the AHC system, improving its precision. However, AHC cranes located on ships require weight control, minimizing weight as much as possible. Excessive crane weight can affect ship stability and increase fuel costs. Therefore, further structural optimization and weight reduction design are necessary without compromising performance. Summary of the Invention

[0003] The present invention aims to solve the problem of high production, operation and maintenance costs caused by the excessive weight of existing cranes.

[0004] To achieve the above objectives, the technical solution of the present invention is: a torque compensation method for an AHC crane, which is used to compensate for the additional torque generated by the boom movement of the AHC crane in a dynamic environment. The crane includes a connected crane body and a boom. The boom includes a main boom and a folding boom. A main hook assembly and an auxiliary hook assembly are provided on the boom. The auxiliary hook assembly includes an auxiliary winch provided on the main boom, an auxiliary pulley block provided at the front end of the folding boom, and an auxiliary fixed pulley provided between the auxiliary winch and the auxiliary pulley block. The specific steps of the torque compensation method for AHC cranes include: S1. A force sensor is installed at the auxiliary fixed pulley to transmit the tension data of the wire rope at the auxiliary fixed pulley to the control system in the crane body; S2. A correction program is set in the force sensor at the auxiliary fixed pulley. This correction program will combine the swing angles of the boom and the main boom in real time to correct the data measured by the force sensor, so that the data transmitted by the force sensor to the control system will not be affected by the swing of the boom.

[0005] This solution incorporates a correction program in the force sensor located at the auxiliary fixed pulley. This program, combined with the swing angles of the boom and main boom, corrects the data measured by the force sensor in real time. This ensures that the data transmitted from the force sensor to the control system is not affected by the boom's swing. It eliminates the need for a fixed pulley at the point of contact of the auxiliary hook wire rope, changing the mainstream three-pulley structure to a two-pulley structure. This reduces the overall weight of the crane without affecting its performance, increases the stability of the hull, and lowers production, operation, and maintenance costs.

[0006] Furthermore, the main hook assembly includes a main winch mounted on the crane body, a first fixed pulley mounted at the extinguishing point, a second fixed pulley mounted between the main winch and the first fixed pulley, and a main pulley assembly mounted between the first fixed pulley and the auxiliary pulley assembly. The main and auxiliary hook assemblies consist of two sets of winches and pulley assemblies, which can work independently without interfering with each other and can be used in different working environments, thus increasing the application scenarios.

[0007] Furthermore, a second bracket extends upward from the end of the folding boom near the main boom, and a second fixed pulley is mounted on the second bracket; a first bracket is also mounted on the folding boom, and a first fixed pulley is mounted on the first bracket; this allows the first and second fixed pulleys to be securely fixed to the boom, while separating the first and second fixed pulleys to avoid mutual interference.

[0008] Furthermore, the folding arm is shaped like the number seven, with the first and second supports separated by a corner and positioned near the corner; the corner separates the force measuring area and the guide area, reducing the impact of nonlinear friction on the dynamic response speed of the AHC system.

[0009] Furthermore, the bend angle of the U-shaped folding arm is α, 90°≤α≤150°; the line connecting the axes of the first and second fixed pulleys forms an angle β with the line connecting the axes of the first fixed pulley and the main pulley group, α<β<180°; when α is an obtuse angle, the bend of the folding arm is gentler, the force generated by the main hook load has a larger axial component along the folding arm direction, and a smaller lateral bending moment, while making the overall profile of the crane more compact when the arm is retracted, reducing the space occupied on the ship's deck; while β is greater than α, it can ensure that the wire rope is not interfered with by the folding arm when it is led from the second fixed pulley to the first fixed pulley.

[0010] Furthermore, an inner cavity is provided at the end of the folding boom near the main boom, and the auxiliary fixed pulley is located in the inner cavity; the auxiliary hook wire rope starts from the auxiliary winch and can directly enter the inner cavity at the root of the folding boom, pass through the auxiliary fixed pulley and be guided to the auxiliary pulley group at the front end of the folding boom, reducing unnecessary friction points and energy loss; at the same time, it separates the main hook line from the auxiliary hook line, so that they do not interfere with each other. Attached Figure Description

[0011] Figure 1This is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the boom in the retracted state according to an embodiment of the present invention; Figure 3 This is a flowchart of an embodiment of the present invention. Detailed Implementation

[0012] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0013] like Figures 1 to 3 As shown, a torque compensation method for an AHC crane is disclosed. This method is used to compensate for the additional torque generated by the boom movement of the AHC crane in a dynamic environment. The crane includes a connected crane body 1 and a boom 2. The boom 2 includes a main boom 21 and a folding boom 22. A main hook assembly 3 and an auxiliary hook assembly 4 are provided on the crane body 1 and the boom 2. The main hook assembly 3 includes a main winch 31 provided on the crane body 1, a first fixed pulley 32 provided at the extinguishing point, a second fixed pulley 33 provided between the main winch 31 and the first fixed pulley 32, and a main pulley assembly 34 provided between the first fixed pulley 32 and the auxiliary pulley assembly 42. The auxiliary hook assembly 4 includes an auxiliary winch 41 provided on the main boom 21, an auxiliary pulley assembly 42 provided at the front end of the folding boom 22, and an auxiliary fixed pulley 43 provided between the auxiliary winch 41 and the auxiliary pulley assembly 42.

[0014] A force sensor is installed at the first fixed pulley 32. The line connecting the axes of the first fixed pulley 32 and the second fixed pulley 33 forms an angle β with the line connecting the axes of the first fixed pulley 32 and the main pulley group 34. When the boom 22 or the jib 2 swings, the degree of the angle β does not change. Therefore, the wire rope tension data measured by the force sensor at the first fixed pulley 32 is not affected by the swing of the jib 2. The sensor can perceive the true tension of the wire rope more accurately, providing a more accurate input for subsequent torque calculation and AHC compensation, thereby improving the accuracy of the entire compensation system.

[0015] The main and auxiliary hook assemblies consist of two sets of winches and pulley blocks, which can work independently without interfering with each other. The control system can perform independent AHC torque compensation for the main and auxiliary hooks respectively. In the mainstream structure, the auxiliary hook assembly 4 also includes a fixed pulley at the neutral point. However, in order to reduce the weight of the crane, in this embodiment, the fixed pulley at the neutral point in the auxiliary hook assembly 4 is omitted. Instead, the force sensor that should have been located at the neutral point is placed at the auxiliary fixed pulley 43, and the tension data of the wire rope at the auxiliary fixed pulley 43 is transmitted to the control system in the crane body 1. At the same time, a correction program is set in the force sensor. This correction program will combine the swing angle of the boom 22 and the main boom 21 in real time to correct the data measured by the force sensor, so that the data transmitted by the force sensor to the control system will not be affected by the swing of the boom 2.

[0016] It eliminates the need for a complete set of fixed pulleys, brackets, and their associated structures at the point of deactivation of the auxiliary hook, replacing some hardware with software intelligence, thereby achieving weight reduction. At the same time, it reduces the winding path and number of guides of the wire rope, reducing system complexity and potential failure points.

[0017] In this embodiment, the folding arm 22 is in the shape of a number seven. A second support 23 extends upward from the end of the folding arm 22 near the main arm 21, and a second fixed pulley 33 is disposed on the second support 23. A first support 24 is also disposed on the folding arm 22, and a first fixed pulley 32 is disposed on the first support 24. That is, the first support 24 and the second support 23 are separated by a corner and are disposed near the corner.

[0018] The first fixed pulley 32, which plays a key force measurement role, is placed separately on the first support 24, so that it can sense only the longitudinal tension of the main hook load transmitted through the main pulley group 34. The second fixed pulley 33, which plays a role in guiding and angle conversion of the wire rope, is placed on an independent second support 23. The radial force generated when the main winch 31 winds up and unwinds the wire rope, the vibration of the wire rope, and the lateral force caused by the swing of the boom 22 are mostly absorbed and isolated by the second support 23, which greatly reduces the interference of these noise signals to the force sensor on the first support 24, and provides a more accurate and stable input source for the torque calculation and active compensation of the AHC system.

[0019] The angle of the 7-shaped folding boom 22 is α, 90°≤α≤150°, and α<β<180°. In this embodiment, the angle of α is 120° and the angle of β is 150°. When α is an obtuse angle, the bend of the folding boom 22 is gentler. The force generated by the main hook load has a larger axial component along the direction of the folding boom 22 and a smaller lateral bending moment. This improves the stress condition at the root of the folding boom 22 and makes the overall profile of the crane more compact when the boom is retracted, reducing the space occupied on the ship's deck. When β is greater than α, it can be ensured that the wire rope will not be interfered with by the folding boom 22 when it is led from the second fixed pulley 33 to the first fixed pulley 32.

[0020] In this embodiment, an inner cavity is provided at one end of the folding arm 22 near the main arm 21, and the auxiliary fixed pulley 43 is disposed in the inner cavity; the auxiliary hook wire rope starts from the auxiliary winch 41 and can directly enter the inner cavity at the root of the folding arm 22, pass through the auxiliary fixed pulley 43 and be guided to the auxiliary pulley group 42 at the front end of the folding arm 22, reducing unnecessary friction points and energy loss; at the same time, it separates the main hook line from the auxiliary hook line, so that they do not interfere with each other.

[0021] The torque compensation method for the AHC crane described above includes the following specific steps: S1. A force sensor is installed at the auxiliary fixed pulley 43 to transmit the tension data of the wire rope at the auxiliary fixed pulley 43 to the control system in the crane body 1. S2. A correction program is set in the force sensor at the auxiliary fixed pulley 43. This correction program will combine the swing angle of the folding boom 22 and the main boom 21 in real time to correct the data measured by the force sensor, so that the data transmitted by the force sensor to the control system will not be affected by the swing of the boom 2.

[0022] The aforementioned structure incorporates a correction program in the force sensor located at the auxiliary fixed pulley 43. This correction program continuously adjusts the data measured by the force sensor in real time based on the swing angles of the folding boom 22 and the main boom 21, ensuring that the data transmitted from the force sensor to the control system is not affected by the swing of the boom 2. By intelligently replacing some hardware with software, weight reduction is achieved. This also reduces the winding paths and guiding times of the wire rope, lowers system complexity and potential failure points, reduces the overall weight of the crane without affecting its performance, increases the stability of the hull, and reduces production, operation, and maintenance costs.

Claims

1. A torque compensation method for an AHC crane, the method being used to compensate for the additional torque generated by the boom movement of the AHC crane in a dynamic environment, the crane comprising a connected crane body (1) and boom (2), characterized in that: The boom (2) includes a main boom (21) and a folding boom (22), and a main hook assembly (3) and a secondary hook assembly (4) are provided on the crane body (1) and the boom (2). The auxiliary hook assembly (4) includes an auxiliary winch (41) mounted on the main boom (21), an auxiliary pulley assembly (42) mounted at the front end of the folding boom (22), and an auxiliary fixed pulley (43) mounted between the auxiliary winch (41) and the auxiliary pulley assembly (42). The specific steps of the torque compensation method for AHC cranes include: S1. A force sensor is installed at the auxiliary fixed pulley (43) to transmit the tension data of the wire rope at the auxiliary fixed pulley (43) to the control system in the crane body (1); S2. A correction program is set in the force sensor at the auxiliary fixed pulley (43). The correction program will combine the swing angle of the folding boom (22) and the main boom (21) in real time to correct the data measured by the force sensor, so that the data transmitted by the force sensor to the control system will not be affected by the swing of the boom (2).

2. The torque compensation method for the AHC crane according to claim 1, characterized in that: The main hook assembly (3) includes a main winch (31) mounted on the crane body (1), a first fixed pulley (32) mounted at the extinguishing point, a second fixed pulley (33) mounted between the main winch (31) and the first fixed pulley (32), and a main pulley assembly (34) mounted between the first fixed pulley (32) and the auxiliary pulley assembly (42).

3. The torque compensation method for the AHC crane according to claim 2, characterized in that: A second bracket (23) extends upward from one end of the folding arm (22) near the main arm (21), and a second fixed pulley (33) is mounted on the second bracket (23); a first bracket (24) is also mounted on the folding arm (22), and a first fixed pulley (32) is mounted on the first bracket (24).

4. The torque compensation method for the AHC crane according to claim 3, characterized in that: The folding arm (22) is shaped like the number seven, with the first support (24) and the second support (23) separated by a corner and located near the corner.

5. The torque compensation method for the AHC crane according to claim 4, characterized in that: The corner of the seven-shaped folding arm (22) is α, 90°≤α≤150°; the line connecting the axis of the first fixed pulley (32) and the axis of the second fixed pulley (33) forms an angle β with the line connecting the axis of the first fixed pulley (32) and the axis of the main pulley group (34), α<β<180°.

6. The torque compensation method for an AHC crane according to claim 1, characterized in that: An inner cavity is provided at one end of the folding arm (22) near the main arm (21), and a secondary fixed pulley (43) is provided in the inner cavity.

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