Linear drive actuator for shallow sea steel structure operation platform and active control force calculation method thereof

Abstract

This invention belongs to the field of marine mining engineering equipment technology, and discloses a linear drive actuator for a shallow-sea steel structure operating platform and its active control force calculation method. The actuator includes a first and a second follower rotor unit, an active drive unit, and a linear drive hydraulic cylinder drive unit inside the outer shell. The hydraulic cylinder drives the gear set to rotate, and the gear set drives the first mass block and the second mass block to rotate synchronously in opposite directions. By using an eccentric mass block to change the center of gravity of the first mass block and the second mass block, the centrifugal force is superimposed in a set direction to synthesize the active control force. This invention also provides an active control force calculation method for the actuator, which can accurately analyze the instantaneous control force under any variable speed motion state. By adjusting the speed of the hydraulic cylinder, the frequency and phase of the control force can be adjusted in real time, which can effectively adapt to the excitation of broadband random waves in shallow seas.

Description

Technical Field

[0001] This invention belongs to the field of marine mining engineering equipment technology, and in particular relates to a linear drive actuator for a shallow sea steel structure operation platform and its active control force calculation method. Background Technology

[0002] Shallow-sea steel structure operating platforms have been widely used in seabed mineral resource extraction, offshore wind power and photovoltaic power station construction, and other fields, becoming a core basic equipment for developing and utilizing shallow-sea natural resources. The shallow-sea marine environment is complex and changeable. Platforms are subjected to periodic horizontal reciprocating impact loads from waves over long periods. Furthermore, the mass of the platform's production equipment and supporting facilities is mostly concentrated on the upper deck above sea level, resulting in a large overall vertical height and significant height effect. Under wave impact, this makes them highly susceptible to large lateral vibrations. These vibrations not only seriously threaten the operational safety of personnel and equipment on deck and reduce the operational accuracy of precision devices, but also generate alternating stresses at critical nodes of the steel structure, leading to structural fatigue damage. In extreme sea conditions, this can even cause structural instability and capsizing, severely restricting the safe and stable operation of the platform.

[0003] Currently, the technical solutions for vibration control of offshore platforms are mainly divided into two categories: passive control and active control. Although passive control technology has advantages such as no need for external energy, simple structure, and good economy and reliability, its control parameters are fixed and it can only effectively suppress vibrations in a specific narrow frequency band. When faced with the wide frequency, random, and reciprocating periodic decay excitation characteristics of shallow sea waves, the control effect drops significantly, resulting in significant application limitations.

[0004] While active control technology offers excellent control performance and strong environmental adaptability, and has been widely used in the field of land-based building structures, traditional hydraulic actuators require large-volume hydraulic systems and inertial mass blocks. However, the limited space on platform decks makes it difficult to install large devices, and miniaturization cannot provide the reaction force to match wave loads. At the same time, the rigid connection between the actuator and the structure and inertial mass can easily lead to problems such as limited stroke, difficulty in ensuring straightness, and component jamming and wear. In addition, the high salt spray and strong corrosion environment at sea further exacerbates the risk of device failure, resulting in high operation and maintenance costs and insufficient long-term reliability.

[0005] In summary, existing technologies cannot simultaneously meet the core requirements of small-volume installation, high thrust output, and high reliability of actuators for shallow-sea platforms. Developing dedicated linear drive actuators adapted to shallow-sea operating conditions is of great significance for ensuring platform operation safety and promoting the localization of marine engineering equipment. Summary of the Invention

[0006] To address the limitations of existing technologies in achieving small-volume installation, high thrust output, and high reliability for actuators used on shallow-sea platforms, this invention provides a dedicated linear drive actuator adapted to shallow-sea operating conditions and its main force calculation method.

[0007] To achieve this technical objective, the present invention adopts the following solution:

[0008] A linear drive actuator for a shallow-sea steel structure work platform includes an outer housing. Inside the outer housing are installed a first follower rotor unit, a second follower rotor unit, a drive unit, and a straight-curved transition joint. An externally convex transition joint is also provided, with its lower end connected to the straight-curved transition joint and its upper end protruding from the top of the outer housing. An internally concave transition joint is connected to the upper end of the externally convex transition joint, and the upper end of the internally concave transition joint is connected to a linear drive hydraulic cylinder. The key feature is that...

[0009] The outer casing includes a middle plate, a gear protective shell, and a rotor protective shell. The middle plate is a rectangular flat plate with a first stepped limiting hole in the left half and a rectangular through hole in the right half. The gear protective shell has an open upper section containing a gear protective cavity and is fixed to the lower side of the middle plate. A first rotating bracket and a second rotating bracket are fixedly connected at intervals below the rectangular through hole on the bottom surface of the gear protective shell. The first and second rotating brackets have through-holes for rotating shafts. A second stepped limiting hole is located below the first stepped limiting hole on the bottom surface of the gear protective shell. The rotor protective shell has an open lower section containing a rotor protective cavity and is fixed to the upper left half of the middle plate.

[0010] The first follower rotor unit consists of a first straight bevel gear, a shaft, a first frustum, and a first mass block. The lower end of the shaft is installed in a second step limiting hole, and the first straight bevel gear is fixedly connected to the lower part of the shaft with the small end of the first straight bevel gear facing upward. The upper end of the shaft passes through the first step limiting hole and extends into the rotor protective shell. The upper end of the shaft is fixedly connected to the first frustum. A first mass block is fixedly connected to one side of the first frustum via a first mass handle. The first mass block is fan-shaped and concentrically arranged with the first frustum. Several first mass center adjustment holes are opened on the surface of the first mass block, and eccentric mass blocks are installed in some of the first mass center adjustment holes.

[0011] The second follower rotor unit consists of a bushing, a second spur bevel gear, a second frustum, and a second mass block. The bushing is fitted onto the outside of the rotating shaft and installed in the first step limiting hole. The lower end of the bushing is fixed to the second spur bevel gear, which is located in the gear protective cavity with its small end close to the first spur bevel gear. The upper end of the bushing is fixed to the second frustum, which is located in the rotor protective shell. A second mass block is fixed to one side of the second frustum via a second mass handle. The second mass block is fan-shaped and concentric with the second frustum. Several second mass center adjustment holes are opened on the surface of the second mass block, and eccentric mass blocks are installed in some of the second mass center adjustment holes.

[0012] The active drive unit consists of an active spur bevel gear and an active shaft. The active spur bevel gear is positioned between the first and second spur bevel gears and meshes with both. The active spur bevel gear is fixed to the back side of the active shaft. The outer end of the active shaft is rotatably mounted in the rotating shaft hole of the first rotating bracket. The end face of the active shaft is provided with a shaft groove.

[0013] The straight-curved transition joint includes two transition joint plates, which are fixedly connected by a slide rod. The slide rod is eccentrically set, and a thin shaft and a thick shaft are respectively fixed to the center of the outer surfaces of the two transition joint plates that are far apart. The outer end of the thin shaft is fixedly installed in the shaft groove, and the outer end of the thick shaft is rotatably installed in the rotating shaft hole of the second rotating bracket.

[0014] The convex transition joint includes a long support rod, with a connecting hole at the lower end of the long support rod. The connecting hole is movably fitted onto the surface of the slide rod, and an convex circular hinge ball is provided at the upper end of the long support rod.

[0015] The concave transition joint includes a long cylinder with a concave limiting groove at the lower end. The convex circular hinge ball is installed inside the concave limiting groove and is in clearance fit with the concave limiting groove. The upper end of the long cylinder is provided with a threaded end, which is threadedly connected to the piston of the linear drive hydraulic cylinder.

[0016] The preferred embodiment of the present invention is as follows:

[0017] Preferably, the first mass handle is a fan-shaped structure, with its wide end fixed to the first mass block and its narrow end fixed to the side wall of the first frustum; the second mass handle is a fan-shaped structure, with its wide end fixed to the second mass block and its narrow end fixed to the side wall of the second frustum. The fan-shaped first and second mass handles make the connection more stable.

[0018] Preferably, both the first and second mass center adjustment holes are internally threaded slots, and the eccentric mass block has external threads on its surface. These threads engage with the first and second mass center adjustment holes, giving the eccentric mass block a fixed weight. Threaded installation of the eccentric mass block is more convenient.

[0019] Preferably, the inner hole of the bushing tube and the rotating shaft are in a clearance fit with a clearance of 2mm; the shaft joint groove and the thin shaft are in an interference fit with an interference of 0.02mm. A reasonable clearance fit facilitates installation while ensuring flexibility in relative movement, and a reasonable interference fit ensures stable and reliable transmission.

[0020] Preferably, the connecting hole and the slide rod are clearance-fitted with a clearance of 2mm; the outer diameter of the thick shaft is the same as the outer diameter of the drive shaft. This allows the first and second rotating supports to have identical structures, differing only in position, facilitating manufacturing.

[0021] Preferably, the first and second step limiting holes are provided with step grooves, and a buffer sleeve is embedded in the step groove. The buffer sleeve is made of an elastomeric material, and an assembly hole is opened in the middle of the buffer sleeve. The rotating shaft and bushing tube pass through the assembly hole. The buffer sleeve avoids wear between rigid components, and a flexible mating surface is formed between the buffer sleeve and the first and second follower rotor units, improving the stability of the components during rotation.

[0022] Preferably, when the first spur bevel gear, the second spur bevel gear, and the driving spur bevel gear are in meshing condition, the tooth tip clearance gradually decreases from the large end to the small end, ensuring meshing stability.

[0023] To address the aforementioned problem, this invention also provides a method for calculating the active control force of a linear drive actuator for a shallow-sea steel structure operating platform. Based on the aforementioned linear drive actuator for a shallow-sea steel structure operating platform, the piston of the linear drive hydraulic cylinder completes one full reciprocating stroke, driving the straight-curved transition joint and the active straight bevel gear to rotate one revolution; the mass of the first mass block is equal to the mass of the second mass block, and the sum of their masses is... ,

[0024] S1: Calculate the angular velocity of the driving spur bevel gear. :

[0025] One stroke of a linear hydraulic cylinder is In the formula This refers to the maximum distance between the convex hinge ball and the center of the rotating shaft hole during the movement of the convex transition joint. This refers to the minimum distance between the convex hinge ball and the center of the rotating shaft hole during the movement of the convex transition joint.

[0026] The total stroke of a linearly driven hydraulic cylinder to complete one reciprocating motion is The working cycle of the actuator for:

[0027]

[0028] In the formula: The speed of motion of the linearly driven hydraulic cylinder;

[0029] Instantaneous angular velocity of a driving spur bevel gear for:

[0030]

[0031] In the formula: Pi is the mathematical constant of a circle.

[0032] S2: Calculate the transmission ratio of the first and second spur bevel gears relative to the driving spur bevel gear. , :

[0033]

[0034]

[0035] In the formula:

[0036] This represents the transmission ratio between the first spur bevel gear and the driving spur bevel gear. This is the transmission ratio between the second spur bevel gear and the driving spur bevel gear;

[0037] Let be the pitch circle radius of the first straight bevel gear. Let be the pitch circle radius of the second spur bevel gear; The pitch circle radius of the driving spur bevel gear.

[0038] The cone angle of the first straight bevel gear. The cone angle of the second spur bevel gear. This is the cone angle of the active spur bevel gear.

[0039] S3: Calculate the instantaneous angular velocities of the first and second spur bevel gears. , :

[0040]

[0041] .

[0042] S4: Calculate the centrifugal force and tangential force of the eccentric mass block:

[0043] When the eccentric mass block rotates along the fixed axis with the first and second spur bevel gears, it generates radial centrifugal force. , With tangential inertial force , ,

[0044] Centrifugal force (radial):

[0045]

[0046]

[0047] Tangential force (tangential):

[0048]

[0049]

[0050] In the formula:

[0051] This represents the distance between the center of mass of the first mass block and the center of rotation of the second mass block.

[0052] S5: Calculate the magnitude of the resultant force of the first mass block, the second mass block, and the eccentric mass block. :

[0053]

[0054] .

[0055] S6: The active control force composition of the opposite rotation of the first and second spur bevel gears:

[0056] Since the first and second mass blocks rotate synchronously at the same speed in opposite directions, their eccentric angles are equal in magnitude and opposite in direction. Therefore, the radial centrifugal forces generated by the first and second mass blocks have equal magnitudes and opposite directions in the eccentric radial component, canceling each other out as internal forces. Thus, the instantaneous active control force output by the actuator system... for:

[0057]

[0058] Formula 13 is the equation for the active force curve provided by either the first mass block or the second mass block.

[0059] Furthermore, when the first and second mass blocks are driven at a constant angular velocity, the actuator operates in continuous rotation mode. At this time, the angular acceleration is 0, and the control force is simplified to a harmonic control force. The calculation formula is:

[0060] .

[0061] Substituting Formula 1 and Formula 2 into Formula 14, we obtain the expression for the single-stroke speed of the linearly driven hydraulic cylinder in terms of the control force output:

[0062] Formula 15

[0063] Formulas 14 and 15 are the active control force calculation equations for the linear drive actuators of the shallow sea steel structure work platform in continuous rotation mode.

[0064] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0065] This invention employs a single hydraulic device as the sole drive source. Through an innovative transmission design of coaxial, opposite-rotation, it significantly reduces the weight of the inertial mass block and the overall volume of the actuator while ensuring stable output of the active control force. This solves the core problem of traditional hydraulic actuators requiring large-volume hydraulic systems and massive inertial support structures, making them difficult to install on shallow-sea platform decks with limited space. It also reduces the additional load on the platform structure. Furthermore, the active control force provided by this invention can be adjusted by changing the weight of the adjustable mass block. The linear motion speed of the linear drive hydraulic cylinder can also be adjusted to change the rotational speed of the active spur bevel gear, thereby real-time adjustment of the rotational speed and initial phase of the eccentric rotor. This provides strong adaptability to the wide-frequency, reciprocating, periodically decaying excitation characteristics of shallow-sea waves. Attached Figure Description

[0066] Figure 1 This is an isometric view of a linear drive actuator for a shallow-sea steel structure work platform according to the present invention;

[0067] Figure 2 This is a top view of a linear drive actuator for a shallow-sea steel structure work platform according to the present invention;

[0068] Figure 3 for Figure 2 Cross-sectional view at point AA;

[0069] Figure 4 for Figure 2 Cross-sectional view at point BB;

[0070] Figure 5 for Figure 2 Cross-sectional view at CC;

[0071] Figure 6 This is a three-dimensional structural diagram of the first follower rotor unit;

[0072] Figure 7 This is a three-dimensional structural diagram of the second follower rotor unit;

[0073] Figure 8 A three-dimensional structural diagram of an active spur bevel gear;

[0074] Figure 9 A three-dimensional schematic diagram of the straight-curved transition section;

[0075] Figure 10 This is a three-dimensional schematic diagram of a gear protective shell;

[0076] Figure 11 This is a three-dimensional schematic diagram of the rotor protective shell;

[0077] Figure 12 This is a three-dimensional schematic diagram of an externally convex transition joint;

[0078] Figure 13 A three-dimensional schematic diagram of the concave transition joint;

[0079] Figure 14 This is a three-dimensional schematic diagram of a linearly driven hydraulic cylinder.

[0080] Figure 15 This is a three-dimensional schematic diagram of the buffer sleeve;

[0081] Figure 16 This is a 3D schematic diagram of the intermediate plate;

[0082] Figure 17 This is a three-dimensional schematic diagram of an eccentric mass block.

[0083] Figure 18 This is a schematic diagram of the motion of a linearly driven hydraulic cylinder.

[0084] Figure 19 This is a schematic diagram of the rotation of the straight-curved transition joint;

[0085] Figure 20 A schematic diagram showing how the active spur bevel gear drives the first and second spur bevel gears to rotate.

[0086] Figure 21 This is a schematic diagram showing the rotation of the first and second mass blocks.

[0087] Figure 22 This invention relates to an explosion-proof linear drive actuator for a shallow-sea steel structure work platform. Figure 1 ;

[0088] Figure 23 This invention relates to an explosion-proof linear drive actuator for a shallow-sea steel structure work platform. Figure 2 ;

[0089] Figure 24 Schematic diagram of the assembly structure of the driving spur bevel gear, the first spur bevel gear, the second spur bevel gear, and the spur-curve transition joint. Figure 1 ;

[0090] Figure 25 Schematic diagram of the assembly structure of the driving spur bevel gear, the first spur bevel gear, the second spur bevel gear, and the spur-curve transition joint. Figure 2 ;

[0091] Figure 26 An exploded view of the assembly structure of the driving spur bevel gear, the first spur bevel gear, the second spur bevel gear, and the straight-curved transition joint;

[0092] Figure 27 To compare the control force curves of the actuator corresponding to different mass weights by adding or removing eccentric mass blocks, the weights of the first and second mass blocks are adjusted. Figure 1 ;

[0093] Figure 28 To compare the control force curves of the actuator corresponding to different mass weights by adding or removing eccentric mass blocks, the weights of the first and second mass blocks are adjusted. Figure 2 ;

[0094] Figure 29 Figure 1 shows an application example of a linear drive actuator for a shallow-sea steel structure work platform.

[0095] Figure 30 The curves of the main force and wave load applied to the offshore platform in Midas in Example 1;

[0096] Figure 31 Displacement cloud diagram of the most unfavorable working condition of the marine structure where the linear drive actuator of the present invention is installed;

[0097] Figure 32 Displacement cloud diagram of the most unfavorable working condition for a marine structure without the linear drive actuator of this invention.

[0098] The diagram is marked as follows:

[0099] The system includes a first follower rotor unit 1, a first spur bevel gear 101, a first mass handle 102, a first mass block 103, a first mass center adjustment hole 10301, a rotating shaft 104, and a first frustum 105.

[0100] The second follower rotor unit 2, the second spur bevel gear 201, the second mass handle 202, the second mass block 203, the second mass center adjustment hole 20301, the second frustum 204, and the bushing 205.

[0101] Active drive unit 3, active spur bevel gear 301, drive shaft 302, shaft groove 303,

[0102] Straight-to-curved transition joint 4, transition joint plate 401, thin shaft 402, thick shaft 403, slide bar 404.

[0103] Gear protective shell 5, first rotating bracket 501, second rotating bracket 502, rotating shaft hole 50101, second step limiting hole 503.

[0104] Rotor protective shell 6, rotor protective cavity 601,

[0105] Outwardly convex transition joint 7, outwardly convex circular hinge ball 701, connecting hole 702.

[0106] Concave transition joint 8, concave limiting groove 801, linear drive hydraulic cylinder 9, buffer sleeve 10, assembly hole 1001, intermediate plate 11, first step limiting hole 1101, rectangular through hole 1102, eccentric mass block 12, offshore operation platform 13, linear drive actuator 20. Detailed Implementation

[0107] To fully understand the purpose, features and effects of the present invention, the present invention will be described in detail through the following specific embodiments, but the present invention is not limited thereto.

[0108] See Figures 1-17 ,as well as Figures 22-26 The present invention provides a linear drive actuator 20 for a shallow sea steel structure working platform, including an outer shell, a first follower rotor unit 1, a second follower rotor unit 2, an active drive unit 3 and a straight-curved conversion joint 4 installed inside the outer shell, and an externally convex conversion joint 7. The lower end of the externally convex conversion joint 7 is connected to the straight-curved conversion joint 4, and the upper end protrudes from the top of the outer shell. The upper end of the externally convex conversion joint 7 is connected to an internally concave conversion joint 8, and the upper end of the internally concave conversion joint 8 is connected to a linear drive hydraulic cylinder 9.

[0109] The structure of each component of the present invention will now be described in detail with reference to the accompanying drawings.

[0110] The outer casing includes an intermediate plate 11, a gear protective shell 5, and a rotor protective shell 6, such as Figure 16 As shown, where,

[0111] The middle plate 11 is a rectangular flat plate with a first step limiting hole 1101 on the left half and a rectangular through hole 1102 on the right half.

[0112] like Figure 10 As shown, the upper end of the gear protective shell 5 is an open structure, and the interior is a gear protective cavity. The upper end of the gear protective shell 5 is fixed to the lower side of the intermediate plate 11. On the surface of the bottom plate of the gear protective shell 5, below the rectangular through hole 1102, a first rotating bracket 501 and a second rotating bracket 502 are fixedly connected at intervals. The first rotating bracket 501 and the second rotating bracket 502 are provided with a rotating shaft hole 50101. On the surface of the bottom plate of the gear protective shell 5, below the first step limiting hole 1101, a second step limiting hole 503 is provided. The second step limiting hole 503 and the first step limiting hole 1101 are on the same vertical line.

[0113] like Figure 11 As shown, the lower end of the rotor protective shell 6 is an open structure, and the interior is a rotor protective cavity 601. The rotor protective shell 6 is fixed to the upper left half of the intermediate plate 11.

[0114] like Figure 6As shown, the first follower rotor unit 1 consists of a first straight bevel gear 101, a rotating shaft 104, a first frustum 105, and a first mass block 103. The lower end of the rotating shaft 104 is installed in the second step limiting hole 503, and the first straight bevel gear 101 is fixedly connected to the lower part of the rotating shaft 104, with the small end of the first straight bevel gear 101 facing upward. The upper end of the rotating shaft 104 passes through the first step limiting hole 1101 and extends into the rotor protective shell 6. The upper end of the rotating shaft 104 is fixedly connected to the first frustum 105, and the first mass block 103 is fixedly connected to one side of the first frustum 105 through the first mass handle 102. The first mass block 103 is fan-shaped and concentrically arranged with the first frustum 105. Several first mass center adjustment holes 10301 are opened on the surface of the first mass block 103, and eccentric mass blocks 12 are installed in some of the first mass center adjustment holes 10301.

[0115] Optionally, the first mass handle 102 has a fan-shaped structure, with its wide end fixedly connected to the first mass block 103 and its narrow end fixedly connected to the side wall of the first frustum 105.

[0116] like Figure 7 As shown, the second follower rotor unit 2 consists of a bushing 205, a second spur bevel gear 201, a second frustum 204, and a second mass block 203. The bushing 205 is fitted onto the outside of the rotating shaft 104 and installed in the first step limiting hole 1101. The lower end of the bushing 205 is fixed to the second spur bevel gear 201, which is located in the gear protective cavity with its small end close to the first spur bevel gear 101. The upper end of the bushing 205 is fixed to the second frustum 204, which is located in the rotor protective shell 6. A second mass block 203 is fixed to one side of the second frustum 204 via a second mass handle 202. The second mass block 203 is fan-shaped and concentrically arranged with the second frustum 204. Several second mass center adjustment holes 20301 are opened on the surface of the second mass block 203, and eccentric mass blocks 12 are installed in some of the second mass center adjustment holes 20301.

[0117] Optionally, the second mass handle 202 is a fan-shaped structure, with its wide end fixed to the second mass block 203 and its narrow end fixed to the side wall of the second frustum 204.

[0118] Optionally, both the first mass center adjustment hole 10301 and the second mass center adjustment hole 20301 are internally threaded slots, and the eccentric mass block 12 has external threads on its surface. The eccentric mass block 12 is screwed into the first mass center adjustment hole 10301 and the second mass center adjustment hole 20301. The eccentric mass block 12 has a fixed weight and is used to adjust the eccentricity of the first mass block 103 and the second mass block 203.

[0119] The inner hole of the bushing 205 is clearance-fitted with the rotating shaft 104, with a clearance of 2mm.

[0120] The active drive unit 3 consists of an active spur bevel gear 301 and an active shaft 302. The active spur bevel gear 301 is disposed between the first spur bevel gear 101 and the second spur bevel gear 201 and meshes with both the first spur bevel gear 101 and the second spur bevel gear 201. The active spur bevel gear 301 is fixedly connected to the active shaft 302 on its back side. The outer end of the active shaft 302 is rotatably mounted in the rotating shaft hole 50101 of the first rotating bracket 501. The end face of the active shaft 302 is provided with a shaft connection groove 303.

[0121] The straight-curved transition joint 4 includes two transition joint plates 401, which are fixedly connected by a slide rod 404. The slide rod 404 is eccentrically set, and a thin shaft 402 and a thick shaft 403 are respectively fixedly connected to the center of the outer surfaces of the two transition joint plates 401. The outer end of the thin shaft 402 is fixedly installed in the shaft groove 303, and the outer end of the thick shaft 403 is rotatably installed in the rotating shaft hole 50101 of the second rotating bracket 502.

[0122] Optionally, the shaft groove 303 and the thin shaft 402 are interference-fitted with an interference amount of 0.02 mm. The outer diameter of the thick shaft 403 is the same as the outer diameter of the drive shaft 302.

[0123] The convex transition joint 7 includes a long support rod with a connecting hole 702 at its lower end. The connecting hole 702 is movably fitted onto the surface of the slide rod 404. The upper end of the long support rod has a convex circular hinge ball 701. The diameter of the connecting hole 702 is larger than the outer diameter of the slide rod 404, forming a clearance fit with a clearance of 2 mm.

[0124] The concave transition joint 8 includes a long cylinder with a concave limiting groove 801 at its lower end. The convex circular hinge ball 701 is installed inside the concave limiting groove 801 and is in clearance fit with the concave limiting groove 801. The upper end of the long cylinder is provided with a threaded end, which is threadedly connected to the piston of the linear drive hydraulic cylinder 9. The concave limiting groove 801 and the convex circular hinge ball 701 are in clearance fit with a clearance of 2mm.

[0125] Furthermore, the first step limiting hole 1101 and the second step limiting hole 503 are provided with step grooves, and a buffer sleeve 10 is embedded in the step groove. The buffer sleeve 10 is made of elastic material, specifically synthetic rubber with a resilience greater than 50%. An assembly hole 1001 is opened in the middle of the buffer sleeve 10, and the rotating shaft 104 and the bushing tube 205 pass through the assembly hole 1001. The step groove and the buffer sleeve 10 adopt an interference fit with an interference amount of 0.02mm.

[0126] The teeth of the first straight bevel gear 101, the second straight bevel gear 201, and the driving straight bevel gear 301 are all distributed on the truncated cone, and the teeth gradually shrink from the large end to the small end. The first straight bevel gear 101 and the second straight bevel gear 201 simultaneously mesh with the driving straight bevel gear 301 for transmission. In the meshing state, the tooth tip clearance gradually decreases from the large end to the small end.

[0127] The first spur bevel gear 101, the second spur bevel gear 201, and the driving spur bevel gear 301 are equivalent gears, and the tooth lengths measured along the generatrix length direction on their pitch cones are consistent. Less than the distance from the apex of its pitch cone to the large end of the gear One-third of it.

[0128] See Figures 18-21 This invention also provides a method for calculating the active control force of a linear drive actuator for a shallow-sea steel structure working platform. Based on the structure of the actuator, the piston of the linear drive hydraulic cylinder 9 completes one full reciprocating stroke (moving from the initial end to the end of the stroke and then returning to the initial end), driving the straight-curved transition joint 4 and the active straight bevel gear 301 to rotate synchronously for one revolution. The reciprocating linear motion cycle of the linear drive hydraulic cylinder 9 is strictly matched with the rotational motion cycle of the active straight bevel gear 301; the sum of the masses of the first mass block 103 and the second mass block 203 is... The first mass block 103 and the second mass block 203 have equal masses, and the mass of each mass block is 1 / 2. The first mass block 103 and the second mass block 203 are installed synchronously (in the same quantity and in the same position) with eccentric mass blocks 12, and the eccentricity of the two is kept consistent by synchronously increasing or decreasing the eccentric mass blocks 12.

[0129] S1: Calculate the angular velocity of the driving spur bevel gear 301 ;

[0130] The stroke of the linear hydraulic cylinder 9 in one movement is In the formula This refers to the maximum distance between the center of the convex circular hinge ball 701 and the center of the rotating shaft hole 50101 during the movement of the convex transition joint 7. This refers to the minimum distance between the center of the externally convex circular hinge ball 701 and the center of the rotating shaft hole 50101 during the movement of the externally convex transition joint 7; for and The difference is the working stroke of the linear hydraulic cylinder 9. The total stroke for completing one round trip is... The working cycle of the actuator for:

[0131]

[0132] In the formula, The speed of movement of the linearly driven hydraulic cylinder (9);

[0133] The instantaneous angular velocity of the driving spur bevel gear 301 for:

[0134]

[0135] In the formula:

[0136] Pi is the mathematical constant of a circle.

[0137] S2: Calculate the transmission ratio of the first spur bevel gear 101 and the second spur bevel gear 201 relative to the driving spur bevel gear 301. , :

[0138]

[0139]

[0140] In the formula:

[0141] The transmission ratio between the first spur bevel gear 101 and the driving spur bevel gear 301 is given. The transmission ratio between the second spur bevel gear 201 and the driving spur bevel gear 301;

[0142] Let be the pitch circle radius of the first spur bevel gear 101. The pitch circle radius of the second spur bevel gear 201; The pitch circle radius of the driving spur bevel gear 301 is...

[0143] The cone angle of the first straight bevel gear 101 is... The cone angle of the second spur bevel gear 201 is... The cone angle of the active spur bevel gear 301.

[0144] S3: Calculate the instantaneous angular velocities of the first spur bevel gear 101 and the second spur bevel gear 201. , :

[0145]

[0146] .

[0147] S4: Calculate the centrifugal force and tangential force of the eccentric mass block:

[0148] When the eccentric mass block 12 rotates along the fixed axis with the first spur bevel gear 101 and the second spur bevel gear 201, it generates radial centrifugal force. , With tangential inertial force , ,

[0149] Centrifugal force (radial):

[0150]

[0151]

[0152] Tangential force (tangential):

[0153]

[0154]

[0155] In the formula:

[0156] It is the distance between the center of mass of the first mass block 103 and the center of rotation of the second mass block 203.

[0157] S5: Calculate the magnitude of the resultant force of the first mass block 103, the second mass block 203, and the eccentric mass block 12. ;

[0158] The centrifugal force is distributed radially, and the tangential force is distributed along the rotational tangential direction. Since they are perpendicular to each other, the instantaneous resultant force amplitude of the first mass block 103 and the second mass block 203 is the vector resultant of the two perpendicular components.

[0159]

[0160]

[0161] Formulas 11 and 12 are analytical expressions for the resultant force of a single eccentric mass block 12 at any time and under any motion state, adaptable to full-condition calculations with variable speed and variable phase.

[0162] S6: The active control force synthesis of the opposite rotation of the first straight bevel gear (101) and the second straight bevel gear (201),

[0163] Since the first mass block 103 and the second mass block 203 move synchronously with the first spur bevel gear 101 and the second spur bevel gear 201 respectively, and the first spur bevel gear 101 and the second spur bevel gear 201 rotate synchronously in opposite directions, the first mass block 103 and the second mass block 203 perform synchronous rotational motions in opposite directions at the same speed. Their eccentric angles are equal in magnitude and opposite in direction. Therefore, the radial centrifugal force generated by the first mass block (103) and the second mass block (203) is in the eccentric radial direction ( If the components of the direction are equal in magnitude and opposite in direction, they cancel each other out as internal forces, then the instantaneous active control force output by the actuator system is... for:

[0164]

[0165] Formula 13 is the active force curve equation provided by either the first mass block 103 or the second mass block 203.

[0166] Specifically, when the first mass block 103 and the second mass block 203 are driven at a constant angular velocity, the actuator operates in continuous rotation mode. At this time, the angular acceleration is 0, and the control force is simplified to a harmonic control force. The calculation formula is:

[0167]

[0168] Formula 14 shows that, under this operating condition, the maximum active control force amplitude output by the actuator is... Control By adjusting the instantaneous angular velocity ( or By adjusting the number of eccentric mass blocks 12, the eccentricity can be adjusted to achieve flexible adjustment of the control force amplitude and frequency, adapting to the vibration control targets of shallow sea steel structure operation platforms under different working conditions.

[0169] Substituting Formula 1 and Formula 2 into Formula 14, we obtain the output force of the control force expressed as the speed of a single stroke of the linearly driven hydraulic cylinder 9:

[0170] Formula 15

[0171] Formulas 14 and 15 are the active control force calculation equations for the linear drive actuators of the shallow-sea steel structure work platform in continuous rotation mode. Formula 14 is the control force calculation based on the first mass block 103 and the second mass block 203. Formula 15 is the control force calculation based on the linear motion speed of the linear drive hydraulic cylinder 9.

[0172] The following explains the principle of the linear drive actuator used in this shallow-sea steel structure work platform. The core of this solution is to convert linear hydraulic power into the synchronous rotational motion of the double eccentric rotors in opposite directions. Through centrifugal force synthesis, a controllable active control force is output, providing active power for vibration control of the shallow-sea steel structure work platform. Its working principle is as follows:

[0173] Driven by a hydraulic piston, the linear drive hydraulic cylinder 9 outputs linear reciprocating motion, which drives the concave conversion joint 8, which is fixed to it, to perform vertical reciprocating linear motion. The concave conversion joint 8 forms a spherical hinge with the convex circular hinge ball 701 through the concave limiting groove 801. The lower end of the convex conversion joint 7 is fitted onto the slide rod 404 of the straight-curved conversion joint 4 through the connecting hole 702, forming a crank-rocker transmission mechanism. When the concave conversion joint 8 performs vertical linear reciprocating motion, it will drive the convex conversion joint 7 to perform reciprocating oscillation with a swing angle, thereby driving the straight-curved conversion joint 4 to rotate around the thick shaft 403 or the thin shaft 402. The straight-curved conversion joint 4 is fixed to the driving spur bevel gear 301 through the thin shaft 402, ultimately converting the linear reciprocating motion of the linear drive hydraulic cylinder 9 into the continuous rotational motion of the driving spur bevel gear 301.

[0174] The shaft 104 of the first follower rotor unit 1 passes through the bushing 205 of the second follower rotor unit 2, so that the first straight bevel gear 101 and the second straight bevel gear 201 are arranged in a relative position; the driving straight bevel gear 301 is arranged between the first straight bevel gear 101 and the second straight bevel gear 201, and meshes with the first straight bevel gear 101 and the second straight bevel gear 201 at the same time, forming two sets of straight bevel gear transmission groups with a shaft intersection angle of 90°.

[0175] When the driving spur bevel gear 301 rotates with the straight-curved transition joint 4, its tooth profile meshes with the tooth profiles of the first spur bevel gear 101 and the second spur bevel gear 201 in sequence, achieving stable transmission. At this time, the first spur bevel gear 101 and the second spur bevel gear 201 will rotate in opposite directions around the same central axis at the same speed, ultimately realizing that a single driving spur bevel gear 301 synchronously drives the first spur bevel gear 101 and the second spur bevel gear 201 to rotate in opposite directions.

[0176] The rotational motion of the first spur bevel gear 101 will drive the first mass block 103 to rotate synchronously, and the rotational motion of the second spur bevel gear 201 will drive the second mass block 203 to rotate synchronously. Both the first mass block 103 and the second mass block 203 are eccentric rotor structures, and they rotate towards each other at the same speed in a parallel plane. When the two sets of eccentric rotors rotate synchronously in opposite directions, the horizontal components of the centrifugal force they generate cancel each other out, while the vertical components are superimposed, ultimately synthesizing a unidirectional excitation force along a set direction, which is the active control force used for platform vibration control.

[0177] This actuator can achieve flexible adjustment of the active control force in two ways: First, by adding or removing the eccentric mass block 12 within the mass center adjustment hole of the first mass block 103 and the second mass block 203, the counterweight mass of the eccentric rotor is changed, thereby adjusting the amplitude of the centrifugal force. Second, by adjusting the linear motion speed of the linear drive hydraulic cylinder 9, the rotational speed of the active spur bevel gear 301 is changed, thereby adjusting the rotational speed and initial phase of the eccentric rotor to achieve different control objectives.

[0178] like Figure 27 and Figure 28 The diagram shows how different control force curves of the actuators can be formed by adding or removing eccentric mass blocks 12, changing the weight of the first mass block 103 and the second mass block 203, and installing different numbers of eccentric mass blocks 12.

[0179] To better illustrate the effects of the present invention, see the following references. Figure 29-32 The diagram illustrates the actual effect of this patented technology.

[0180] Example 1: Using finite element analysis, a 41m high four-pillar offshore working platform 13 was used as the verification object (e.g., Figure 29 As shown), four linear drive actuators 20 of this invention are symmetrically arranged on the deck of the offshore operation platform 13, and their output time history curves are as follows. Figure 30 As shown. The sea surface elevation of structure 13 of the offshore operating platform is 26m, where it bears a wave load with a maximum amplitude of 2×600kN. The corresponding wave load time history curve is shown below. Figure 30 As shown, the load is applied as a periodic point load to the structural nodes, without establishing a finite element model of the solid actuator.

[0181] Numerical analysis models for the above working conditions were established using MIDAS finite element software. Structural baseline models without the linear drive actuator 20 and controlled structural models with the linear drive actuator 20 were constructed. Transient dynamic calculations under the most unfavorable working condition showed that the maximum displacement of the structure with the actuator was 39.86 mm (e.g., ...). Figure 31 As shown), the maximum displacement of the structure without the linear drive actuator 20 is 79.69 mm (as shown). Figure 32 As shown in the figure, the displacement response attenuation of the structure to wave vibration reaches more than 50%, which fully demonstrates that the actuator of the present invention has excellent control effect on building structures subjected to periodic loads.

[0182] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the invention in any way. Any changes or modifications made by those skilled in the art based on the above-disclosed technical content should be considered as equivalent and valid embodiments, and all fall within the scope of protection of the present invention.

Claims

1. A linear drive actuator for a shallow-sea steel structure working platform, comprising an outer shell, wherein a first follower rotor unit (1), a second follower rotor unit (2), an active drive unit (3), and a straight-curved transition joint (4) are installed inside the outer shell, and an externally convex transition joint (7) is also provided, the lower end of which is connected to the straight-curved transition joint (4), the upper end of which protrudes from the top of the outer shell, the upper end of which is connected to an internally concave transition joint (8), and the upper end of which is connected to a linear drive hydraulic cylinder (9), characterized in that, The outer casing includes an intermediate plate (11), a gear protective shell (5), and a rotor protective shell (6). The intermediate plate (11) is a rectangular flat plate with a first step limiting hole (1101) on the left half and a rectangular through hole (1102) on the right half. The gear protective shell (5) has an open structure at the top and a gear protective cavity inside. The gear protective shell (5) is fixed to the lower side of the intermediate plate (11), and the bottom surface of the gear protective shell (5) is located below the rectangular through hole (1102). A first rotating bracket (501) and a second rotating bracket (502) are fixedly connected, and a rotating shaft hole (50101) is provided through the first rotating bracket (501) and the second rotating bracket (502); a second step limiting hole (503) is provided on the bottom plate surface of the gear protective shell (5) below the first step limiting hole (1101); the lower end of the rotor protective shell (6) is an open structure, and the interior is a rotor protective cavity (601). The rotor protective shell (6) is fixedly connected to the upper side of the left half of the intermediate plate (11); The first follower rotor unit (1) consists of a first straight bevel gear (101), a rotating shaft (104), a first frustum (105), and a first mass block (103). The lower end of the rotating shaft (104) is installed in the second step limiting hole (503), and the lower part of the rotating shaft (104) is fixedly connected to the first straight bevel gear (101), with the small end of the first straight bevel gear (101) facing upward. The upper end of the rotating shaft (104) passes through the first step limiting hole (1101) and extends to the rotor protection. In the protective shell (6), the upper end of the rotating shaft (104) is fixedly connected to the first frustum (105). A first mass block (103) is fixedly connected to one side of the first frustum (105) through the first mass handle (102). The first mass block (103) is fan-shaped and concentrically arranged with the first frustum (105). Several first mass center adjustment holes (10301) are opened on the surface of the first mass block (103). An eccentric mass block (12) is installed in some of the first mass center adjustment holes (10301). The second follower rotor unit (2) consists of a bushing (205), a second spur bevel gear (201), a second frustum (204), and a second mass block (203). The bushing (205) is fitted onto the outside of the rotating shaft (104) and installed in the first step limiting hole (1101). The lower end of the bushing (205) is fixed to the second spur bevel gear (201). The second spur bevel gear (201) is located in the gear protective cavity and its small end is close to the first spur bevel gear (101). (205) The upper end is fixed to the second frustum (204). The second frustum (204) is located in the rotor protective shell (6). A second mass block (203) is fixed to one side of the second frustum (204) through the second mass handle (202). The second mass block (203) is fan-shaped and concentrically arranged with the second frustum (204). Several second mass center adjustment holes (20301) are opened on the surface of the second mass block (203). An eccentric mass block (12) is installed in some of the second mass center adjustment holes (20301). The active drive unit (3) consists of an active spur bevel gear (301) and an active shaft (302). The active spur bevel gear (301) is located between the first spur bevel gear (101) and the second spur bevel gear (201) and meshes with both the first spur bevel gear (101) and the second spur bevel gear (201). The active spur bevel gear (301) is fixedly connected to the active shaft (302) on its back side. The outer end of the active shaft (302) is rotatably installed in the rotating shaft hole (50101) of the first rotating bracket (501). The end face of the active shaft (302) is provided with a shaft connection groove (303). The straight-curved transition joint (4) includes two transition joint plates (401), which are fixedly connected by a slide rod (404). The slide rod (404) is eccentrically set, and a thin shaft rod (402) and a thick shaft rod (403) are respectively fixedly connected to the center of the outer surfaces of the two transition joint plates (401). The outer end of the thin shaft rod (402) is fixedly installed in the shaft groove (303), and the outer end of the thick shaft rod (403) is rotatably installed in the rotating shaft hole (50101) of the second rotating bracket (502). The convex transition joint (7) includes a long support rod, with a connecting hole (702) at the lower end of the long support rod. The connecting hole (702) is movably fitted onto the surface of the slide rod (404), and an convex circular hinge ball (701) is provided at the upper end of the long support rod. The concave transition joint (8) includes a long cylinder with a concave limiting groove (801) at the lower end. The convex circular hinge ball (701) is installed inside the concave limiting groove (801) and is in clearance fit with the concave limiting groove (801). The upper end of the long cylinder is provided with a threaded end, which is threadedly connected to the piston of the linear drive hydraulic cylinder (9).

2. The linear drive actuator for a shallow-sea steel structure work platform according to claim 1, characterized in that, The first mass handle (102) is a fan-shaped structure, with its wide end fixed to the first mass block (103) and its narrow end fixed to the side wall of the first frustum (105); the second mass handle (202) is a fan-shaped structure, with its wide end fixed to the second mass block (203) and its narrow end fixed to the side wall of the second frustum (204).

3. The linear drive actuator for a shallow-sea steel structure work platform according to claim 1, characterized in that, The first mass center adjustment hole (10301) and the second mass center adjustment hole (20301) are both internal threaded slots. The eccentric mass block (12) has an external thread on its surface. Its thread is screwed into the first mass center adjustment hole (10301) and the second mass center adjustment hole (20301). The eccentric mass block (12) has a fixed weight.

4. The linear drive actuator for a shallow-sea steel structure work platform according to claim 1, characterized in that, The inner hole of the bushing (205) and the rotating shaft (104) are clearance fit, with a clearance of 2mm; the shaft groove (303) and the thin shaft (402) are interference fit, with an interference of 0.02mm.

5. The linear drive actuator for a shallow-sea steel structure work platform according to claim 1, characterized in that, The connecting hole (702) and the slide rod (404) are clearance fit, with a clearance of 2mm; the outer diameter of the thick shaft (403) is the same as the outer diameter of the drive shaft (302).

6. The linear drive actuator for a shallow-sea steel structure work platform according to claim 1, characterized in that, Both the first step limiting hole (1101) and the second step limiting hole (503) are provided with step grooves, and a buffer sleeve (10) is embedded in the step groove. The buffer sleeve (10) is made of elastomeric material, and an assembly hole (1001) is opened in the middle of the buffer sleeve (10). The rotating shaft (104) and the bushing tube (205) are inserted into the assembly hole (1001).

7. The linear drive actuator for a shallow-sea steel structure work platform according to claim 1, characterized in that, When the first straight bevel gear (101), the second straight bevel gear (201), and the driving straight bevel gear (301) are in gear meshing state, the tooth tip clearance gradually decreases from the large end to the small end.

8. A method for calculating the active control force of a linear drive actuator for a shallow-sea steel structure operating platform, based on the linear drive actuator for a shallow-sea steel structure operating platform as described in claim 1, wherein the piston of the linear drive hydraulic cylinder (9) completes one full reciprocating stroke, driving the straight-curved conversion joint (4) and the active straight bevel gear (301) to rotate one revolution; the mass of the first mass block (103) is equal to the mass of the second mass block (203), and the sum of their masses is equal to the mass of the second mass block (203). , S1: Calculate the angular velocity of the driving spur bevel gear (301) : The stroke of a linear hydraulic cylinder (9) in one movement is In the formula The maximum distance between the center of the convex concave pivot ball (701) and the center of the rotating shaft hole (50101) during the movement of the convex transition joint (7); The minimum distance between the center of the convex circular hinge ball (701) and the center of the rotating shaft hole (50101) during the movement of the convex transition joint (7); The total stroke of the linear drive hydraulic cylinder (9) to complete one reciprocating motion is The working cycle of the actuator for: ， In the formula: The speed of movement of the linearly driven hydraulic cylinder (9); Instantaneous angular velocity of the driving spur bevel gear (301) for: ， In the formula: Pi; S2: Calculate the transmission ratio of the first spur bevel gear (101) and the second spur bevel gear (201) relative to the driving spur bevel gear (301). , : ； ， In the formula: The transmission ratio between the first spur bevel gear (101) and the driving spur bevel gear (301) is given. The transmission ratio between the second spur bevel gear (201) and the driving spur bevel gear (301); Let be the pitch circle radius of the first straight bevel gear (101). Let be the pitch circle radius of the second spur bevel gear (201); The pitch circle radius of the driving spur bevel gear (301) is... The cone angle of the first straight bevel gear (101) is... The cone angle of the second spur bevel gear (201) is... The cone angle of the active spur bevel gear (301); S3: Calculate the instantaneous angular velocities of the first spur bevel gear (101) and the second spur bevel gear (201). , : ； ， S4: Calculate the centrifugal force and tangential force of the eccentric mass block (12): When the eccentric mass block (12) rotates along the fixed axis with the first spur bevel gear (101) and the second spur bevel gear (201), it generates radial centrifugal force. , With tangential inertial force , , Centrifugal force (radial): ； ， Tangential force (tangential): ； ， In the formula: The distance between the center of mass of the first mass block (103) and the center of rotation of the second mass block (203) is the distance from their center of rotation. S5: Calculate the magnitude of the combined force of the first mass block (103), the second mass block (203), and the eccentric mass block (12). : ； ， S6: Combination of active control forces for the opposite rotation of the first spur bevel gear (101) and the second spur bevel gear (201): Since the first mass block (103) and the second mass block (203) rotate synchronously at the same speed in opposite directions, their eccentric angles are equal in magnitude and opposite in direction. Therefore, the radial centrifugal forces generated by the first mass block (103) and the second mass block (203) have equal magnitudes and opposite directions in the eccentric radial component, and cancel each other out as internal forces. Thus, the instantaneous active control force output by the actuator system... for: ， Formula 13 is the active force curve equation provided by either the first mass block (103) or the second mass block (203).

9. The method for calculating the active control force of a linear drive actuator for a shallow-sea steel structure work platform according to claim 8, characterized in that: When the first mass block (103) and the second mass block (203) are driven at a constant angular velocity, the actuator operates in continuous rotation mode. At this time, the angular acceleration is 0, and the control force is simplified to a harmonic control force. The calculation formula is: ， Substituting Formula 1 and Formula 2 into Formula 14, we obtain the single-stroke speed expression of the linearly driven hydraulic cylinder (9) for the control force output: Official 15, Formulas 14 and 15 are the active control force calculation equations for the linear drive actuators of the shallow sea steel structure work platform in continuous rotation mode.

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