A marine generator set variable-damping type magnetic fluid coupling and a control method thereof

Abstract

This invention provides a variable damping magnetohydrodynamic coupler for marine generator sets and its control method, comprising a housing, an input shaft, an output shaft, an excitation assembly, a control unit, a piezoelectric element assembly, and an auxiliary sensing assembly. A damping cavity is provided within the housing. The excitation assembly includes a magnetorheological fluid, an excitation coil, and a magnetic ring. The magnetorheological fluid fills the damping cavity, and the excitation coil adjusts the magnetic field of the magnetic ring through the excitation current to control the damping torque of the magnetorheological fluid. Based on the controllable viscosity of the magnetorheological fluid, the damping torque can be continuously adjusted over a wide range of 50~500 Nm by adjusting the excitation current to change the magnetic field strength, dynamically adapting to complex operating conditions such as shipboard turbulence and sudden load changes. Combined with the micro-compensation function of the piezoelectric element assembly, the coaxiality accuracy of the shaft system is improved to ±0.002 mm, and the resonance risk caused by over-compensation under high-speed conditions is avoided through a speed correction coefficient.

Description

Technical Field

[0001] This invention relates to the field of marine power transmission technology, and in particular to a variable damping magnetohydrodynamic coupler for marine generator sets and its control method. Background Technology

[0002] Marine safety-grade diesel generator sets are core emergency support equipment for ships, and the connection structure between the crankshaft and the generator rotor directly determines the power transmission efficiency and operational safety. Existing connection methods are mainly divided into two categories, both with inherent defects: one is the rigid flange bolt connection, which has extremely low coaxiality tolerance, and the additional bending moment generated by ship turbulence can easily cause a chain of failures such as bearing wear and shaft deformation; the other is the flexible connection using elastic couplings, which relies on elastic elements such as rubber / springs for buffering, but these elements are prone to aging and failure after long-term service, and their fixed damping characteristics cannot adapt to changes in operating conditions in real time, resulting in limited resistance to impact loads.

[0003] Therefore, there is an urgent need to develop a coaxial connection structure that is structurally simple, highly efficient, and has real-time adjustable damping and rapid response capabilities. Summary of the Invention

[0004] This invention provides a variable damping magnetohydrodynamic coupler for marine generator sets and its control method, in order to solve the problems of insufficient transmission stability and shock resistance between the crankshaft and rotor shaft of generator sets in the prior art.

[0005] This invention provides a variable damping magnetohydrodynamic coupler for marine generator sets, comprising a housing, an input shaft, an output shaft, an excitation assembly, a control unit, a piezoelectric element assembly, and an auxiliary sensing assembly;

[0006] A damping cavity is provided inside the housing; The excitation assembly includes a magnetorheological fluid, an excitation coil, and a magnetic ring. The magnetorheological fluid fills the damping cavity, the magnetic ring is fixedly connected to the side wall of the housing, the excitation coil is wound around the magnetic ring, and the excitation coil adjusts the magnetic field of the magnetic ring through the excitation current to control the damping torque of the magnetorheological fluid. The input shaft is rotatably connected to one end of the housing, and the output shaft is rotatably connected to the other end of the housing. A drive wheel is fixedly connected to one end of the input shaft that extends into the housing, and a driven wheel is fixedly connected to one end of the output shaft that extends into the housing. A clearance is provided between the drive wheel and the driven wheel. Multiple grooves are respectively opened on the opposite side of the drive wheel and the driven wheel, and the grooves are arranged radially. The auxiliary sensing component is used to collect the operating parameters of the coupler; The piezoelectric element group is connected to the outer wall of the input shaft and the output shaft, and is used to monitor the radial displacement deviation of the input shaft and the output shaft and to compensate for the radial displacement deviation; The control unit is electrically connected to the piezoelectric element group, the excitation coil, and the auxiliary sensing component, respectively, and is used to adjust the excitation current in the excitation coil and the driving voltage of the piezoelectric element group according to the operating parameters.

[0007] Furthermore, the piezoelectric element group includes multiple piezoelectric ceramics, and multiple piezoelectric ceramics are respectively arranged circumferentially on the input shaft and the output shaft. One end of the piezoelectric ceramic is fixedly connected to the housing, and the other end of the piezoelectric ceramic is in contact with the outer wall of the input shaft or the output shaft.

[0008] Furthermore, the auxiliary sensing component includes: A speed sensor, connected to the input shaft and the output shaft, is used to collect the speed information of the input shaft and the output shaft respectively; A load sensor, connected to the output shaft, is used to monitor the load torque information of the output shaft; A temperature sensor is connected inside the housing to monitor the operating temperature inside the housing.

[0009] Furthermore, sealing rings are respectively connected between the housing and the input shaft, and between the housing and the output shaft.

[0010] Furthermore, a spiral guide groove is formed on the inner wall of the damping cavity.

[0011] This invention also discloses a control method for a variable damping magnetohydrodynamic coupler, applied to a variable damping magnetohydrodynamic coupler for marine generator sets, comprising: Collect operating parameters of the variable damping magnetohydrodynamic coupler; The operating condition level is determined based on the aforementioned operating parameters; Adjust the damping torque and / or radial displacement deviation compensation of the magnetorheological fluid according to the operating condition level to bring the operating parameters to a stable operating condition.

[0012] Furthermore, the operating parameters include load torque information, rotational speed information of the input shaft and output shaft, radial displacement deviation of the input shaft and the output shaft, and operating temperature information within the housing; The determination is based on a comparison between the operating parameters and the set parameter thresholds, including: When |δ r |≤δ r0 When |ω-ω0|≤ω1 and |M-M0|≤M1, ​​it is determined to be a steady working condition; When |δ r |>δ r0 And V δ If ω1 ≤ V1, or ω2 ≥ |ω-ω0| > ω1, or M2 ≥ |M-M0| > M1, then it is determined to be the first level; When ω3≥|ω-ω0|>ω2 or M3≥|M-M0|>M2, it is determined to be the second level; When V δ If the value is >V1, or |ω-ω0|>ω3, or |M-M0|>M3, then it is determined to be the third level; Where, δ r δ represents the radial displacement deviation of the output shaft. r0 ω represents the displacement deviation threshold; ω is the output shaft speed, ω0 is the reference speed, ω1 is the first speed threshold, ω2 is the second speed threshold, ω3 is the third speed threshold, M is the load torque, M0 is the rated load torque, M1 is the first torque fluctuation threshold, M2 is the second torque fluctuation threshold, M3 is the third torque fluctuation threshold, and V is the displacement deviation threshold. δ V1 represents the rate of change of radial displacement deviation of the output shaft, and V1 is the threshold value for the rate of change of displacement deviation.

[0013] Furthermore, adjusting the damping torque and / or radial displacement deviation compensation of the magnetorheological fluid according to the operating condition level to adjust the operating parameters to a stable operating condition includes: When the operating condition level is stable, maintain the current operating parameters and continue monitoring; When the operating condition level is the first level, the compensation amount of radial displacement deviation is adjusted by the piezoelectric element group to restore the operating condition level to the stable operating condition level. When the operating condition level is the second level, the compensation amount of radial displacement deviation is adjusted by the piezoelectric element group, and the damping torque of the magnetorheological fluid is adjusted by the excitation component, so that the operating condition level is restored to the stable operating condition level. When the operating condition level is the third level, the damping torque of the magnetorheological fluid is adjusted to the maximum through the excitation component, while the load is reduced.

[0014] Furthermore, the method for adjusting the compensation amount of radial displacement deviation using the piezoelectric element group is as follows:

[0015] Where s is the compensation amount for the radial displacement deviation of the output shaft, K2 is the piezoelectric compensation coefficient, ω is the rotational speed of the output shaft, ω0 is the reference rotational speed, and δ r This represents the radial displacement deviation of the output shaft. This is the speed correction factor.

[0016] Furthermore, the method for adjusting the damping torque of the magnetorheological fluid through the excitation assembly is as follows: ; ; ; in Let ω be the damping torque of the magnetorheological fluid, R be the inner radius of the damping cavity, L be the axial length of the damping cavity, μ0 be the zero-magnetic-field viscosity of the magnetorheological fluid, and ω be the rotational speed of the output shaft. Let θ be the shear yield strength of the magnetorheological fluid, θ be the helix angle of the spiral guide channel, and M be the load torque. k is the load correction factor, k1 is the magnetic field coefficient, and k t Where I is the temperature correction factor, I is the excitation current, and T is the operating temperature inside the casing.

[0017] The beneficial effects of this invention are as follows: 1. An integrated housing combines the damping cavity, excitation assembly, and piezoelectric element group, eliminating the need for multiple independent drive components, resulting in a more compact design suitable for limited installation space on ships. The radially radiating groove design of the drive and driven wheels, combined with the helical guide channel of the damping cavity, optimizes the flow path and shear stress state of the magnetorheological fluid, improving power transmission efficiency and damping adjustment uniformity. A fluororubber skeleton oil seal adapts to the chemical properties of the magnetorheological fluid and the shaft rotation conditions, achieving long-term sealing of the damping cavity, preventing magnetorheological fluid leakage, and reducing the probability of failure.

[0018] 2. Based on the controllable viscosity of magnetorheological fluids, the damping torque of 50~500N can be achieved by adjusting the excitation current to change the magnetic field strength. With a continuously adjustable range of m, it can dynamically adapt to complex operating conditions such as ship turbulence and sudden load changes. Combined with the micro-compensation function of the piezoelectric element group, the coaxiality accuracy of the shaft system is improved to ±0.002mm, and the resonance risk caused by overcompensation under high-speed conditions is avoided by the speed correction coefficient.

[0019] 3. A hierarchical working condition identification and adjustment strategy based on a multi-parameter mapping model is adopted, which prioritizes piezoelectric fine-tuning for mild fluctuations, combines piezoelectric and magnetorheological adjustment for moderate fluctuations, and combines maximum damping with load unloading for impact conditions, thereby improving the impact resistance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the coupler structure according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram showing the connection relationship between the magnetic ring and the excitation coil in an embodiment of the present invention.

[0022] Figure 3 This is a flowchart illustrating the control method of the variable damping magnetohydrodynamic coupler according to an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the module logic relationship of the control unit in an embodiment of the present invention.

[0024] Figure label: 1. Housing; 11. Damping cavity; 2. Input shaft; 21. Driving wheel; 3. Output shaft; 31. Driven wheel; 4. Magnetic ring; 41. Excitation coil; 5. Piezoelectric element assembly; 6. Sealing ring; 7. Cooling channel; 71. Liquid inlet pipe; 72. Liquid outlet pipe; 73. Heat dissipation fins. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] The terms "first" and "second" in the specification and claims of this invention may explicitly or implicitly include one or more of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] The following is combined with Figures 1-4 This invention describes a variable damping magnetohydrodynamic coupler for marine generator sets and its control method.

[0029] A variable damping magnetohydrodynamic coupler for marine generator sets includes a housing 1, an input shaft 2, an output shaft 3, an excitation assembly, a control unit, a piezoelectric element assembly 5, and an auxiliary sensing assembly. A damping cavity 11 is provided within the housing 1. The excitation assembly includes magnetorheological fluid, an excitation coil 41, and a magnetic ring 4. The magnetorheological fluid fills the damping cavity 11. The magnetic ring 4 is fixedly connected to the side wall of the housing 1. The excitation coil 41 is wound around the magnetic ring 4. The excitation coil 41 adjusts the magnetic field of the magnetic ring 4 through the excitation current to control the damping torque of the magnetorheological fluid. The input shaft 2 is rotatably connected to one end of the housing 1, and the output shaft 3 is rotatably connected to the other end of the housing 1. A driving wheel 21 is fixedly connected to one end of the input shaft 2 extending into the housing 1, and a driven wheel 31 is fixedly connected to one end of the output shaft 3 extending into the housing 1. A clearance is provided between the driving wheel 21 and the driven wheel 31. Multiple grooves are respectively formed on opposite sides of the driving wheel 21 and the driven wheel 31, arranged radially. The auxiliary sensing component is used to collect the operating parameters of the coupler. The piezoelectric element group 5 is connected to the outer wall of the input shaft 2 and the output shaft 3 to monitor and compensate for the radial displacement deviation of the input shaft 2 and the output shaft 3. The control unit is electrically connected to the piezoelectric element group 5, the excitation coil 41 and the auxiliary sensing component, respectively, and is used to adjust the excitation current in the excitation coil 41 and the driving voltage of the piezoelectric element group 5 according to the operating parameters.

[0030] Specifically, such as Figure 1 , Figure 2 As shown, the damping cavity 11 is configured as a cylindrical cavity, and the magnetorheological fluid filling rate is 95% of the volume of the damping cavity 11. The magnetorheological fluid used is a carbonyl iron powder-based magnetorheological fluid, which contains an anti-settling agent and a high-temperature stabilizer. The shear yield strength τ ≥50kPa. The magnetic ring 4 is an electrical pure iron magnetic ring 4, with four sets of excitation coils 41 wound around it. Each set of excitation coils 41 has 500 turns, a rated voltage of 24V, and an operating current adjustment range of 0~3A. The magnetic ring 4 is fixed to the side wall of the housing 1. The input shaft 2 and output shaft 3 are rotatably connected to both ends of the housing 1. The end of the input shaft 2 extending into the housing 1 is fixed to the driving wheel 21, and the end of the output shaft 3 extending into the housing 1 is fixed to the driven wheel 31. A clearance is provided between the driving wheel 21 and the driven wheel 31. Multiple radially arranged grooves are formed on the opposite side of the driving wheel 21 and the driven wheel 31. The piezoelectric element group 5 is connected to the outer walls of the input shaft 2 and the output shaft 3, used to monitor and compensate for radial displacement deviations of the input shaft 2 and the output shaft 3. The control unit adopts an FPGA+ARM dual-core architecture and is electrically connected to the piezoelectric element group 5, the excitation coils 41, and the auxiliary sensing components.

[0031] In one specific embodiment, such as Figure 1 As shown, the drive wheel 21 is configured as a pump wheel, the input shaft 2 is fixed to the output crankshaft of the marine diesel engine via a flange, and the output shaft 3 is fixed to the rotor of the marine generator set via a flange.

[0032] When the magnetohydrodynamic coupler is working, the auxiliary sensing components collect operating parameters such as the coupler's rotational speed, load torque, and temperature in real time and transmit these parameters to the control unit. Based on the received parameters, the control unit calculates the target excitation current, adjusts the current in the excitation coil 41, and thus changes the magnetic field strength of the magnetic ring 4. Changes in magnetic field strength regulate the shear viscosity of the magnetorheological fluid, thereby adjusting the damping torque. The piezoelectric element group 5, based on the direct piezoelectric effect, collects the radial displacement deviation between the input shaft 2 and the output shaft 3 and feeds the deviation signal back to the control unit. Based on the deviation signal and the inverse piezoelectric effect, the control unit outputs a drive command to control the piezoelectric element group 5 to output a micro-displacement compensation amount, correcting the radial displacement deviation and achieving compensation for the radial displacement deviation.

[0033] By integrating magnetorheological damping adjustment and piezoelectric micro-compensation functions, the damping characteristics are adjustable in real time and the coaxiality of the shaft system is precisely corrected, significantly improving the coupler's adaptability to different operating conditions. The radially radial groove design of the driving wheel 21 and the driven wheel 31, combined with the damping effect of the magnetorheological fluid, optimizes the power transmission path and improves power transmission efficiency.

[0034] Furthermore, the piezoelectric element group 5 includes multiple piezoelectric ceramics. Multiple piezoelectric ceramics are arranged circumferentially on the input shaft 2 and the output shaft 3 respectively. One end of the piezoelectric ceramic is fixedly connected to the housing 1, and the other end of the piezoelectric ceramic is in contact with the outer wall of the input shaft 2 or the output shaft 3.

[0035] Specifically, the piezoelectric element group 5 comprises 6 piezoelectric ceramics, with 3 evenly arranged circumferentially on the input shaft 2 and 3 evenly arranged circumferentially on the output shaft 3. One end of each piezoelectric ceramic is fixedly connected to the inner wall of the housing 1, and the other end is in contact with the outer walls of the input shaft 2 and the output shaft 3, respectively. The radial displacement measurement range of the piezoelectric ceramics is ±0.02mm, the measurement accuracy is ±0.001mm, and the micro-displacement compensation range is ±0.01mm.

[0036] Independent monitoring and compensation of the two shafts are achieved through piezoelectric element group 5, improving the overall alignment accuracy of the shaft system. When the input shaft 2 and output shaft 3 experience radial displacement deviation during operation, they compress the corresponding piezoelectric ceramics. The piezoelectric ceramics generate electrical signals based on the direct piezoelectric effect, thus providing feedback on the displacement deviation data. After receiving the electrical signals and calculating the compensation amount, the control unit outputs a drive voltage to the piezoelectric ceramics. Based on the inverse piezoelectric effect, the piezoelectric ceramics undergo expansion and contraction deformation, outputting micro-displacement to precisely compensate for the radial displacement deviation of the input shaft 2 and output shaft 3. The adjustment accuracy can reach ±0.001mm, and the coaxiality accuracy of the shaft system is improved to ±0.002mm, an 80% improvement compared to traditional structures.

[0037] Furthermore, the auxiliary sensing components include: A speed sensor is used to collect the speed information of the input shaft 2 and the output shaft 3 respectively; A load sensor, connected to output shaft 3, is used to monitor the load torque information of output shaft 3; A temperature sensor is connected inside the housing 1 to monitor the operating temperature inside the housing 1.

[0038] Specifically, the auxiliary sensing component includes two speed sensors, one load sensor, and one temperature sensor. One speed sensor acquires the real-time speed of the input shaft 2, and the other speed sensor acquires the real-time speed of the output shaft 3, with a measurement range of 0~2000 r / min; the load sensor is connected to the output end of the output shaft 3 to monitor the load torque of the output shaft 3, with a measurement range of 0~1000 N. m; The temperature sensor is embedded in the inner wall of the housing 1 to monitor the operating temperature in the damping cavity 11, with a measurement range of 5~65℃. All sensor data is transmitted to the control unit via the SPI bus, with a transmission rate of 1Mbps and a response delay of ≤20ms, providing data support for the control unit's condition judgment and parameter adjustment.

[0039] Furthermore, sealing rings 6 are connected between the housing 1 and the input shaft 2, and between the housing 1 and the output shaft 3, respectively.

[0040] Specifically, such as Figure 1 As shown, a sealing ring 6 is installed at the connection between housing 1 and input shaft 2, and at the connection between housing 1 and output shaft 3. The sealing ring 6 is a fluororubber skeleton oil seal. The lip of the sealing ring 6 is interference-fitted with the outer wall of input shaft 2 and output shaft 3, with an interference amount of 0.01~0.02mm. The lip of the sealing ring 6 is tightly attached to the outer wall of input shaft 2 and output shaft 3, and adaptively adjusts the sealing state with the rotation of the shaft, preventing the magnetorheological fluid in the damping cavity 11 from leaking outward, while preventing external dust and moisture from entering the damping cavity 11. The fluororubber skeleton oil seal is adapted to the chemical properties of the magnetorheological fluid and the rotational conditions of the shaft system, achieving long-term sealing of the damping cavity 11 and avoiding the impact of magnetorheological fluid leakage on system reliability.

[0041] Furthermore, a spiral guide groove is formed on the inner wall of the damping cavity 11.

[0042] Specifically, a spiral guide groove is machined on the inner wall of the damping cavity 11. The guide groove has a lead of 15 mm, a width of 5 mm, and a spiral angle of 30°. When the magnetorheological fluid flows within the damping cavity 11, the spiral guide groove guides the fluid along a spiral path, resulting in a more uniform distribution of the fluid within the cavity. This also increases the contact area and shear path between the fluid and the inner wall of the cavity 11. The 30° spiral angle design increases the shear path and enhances the damping effect of the magnetorheological fluid. Combined with the viscosity characteristics of the fluid, this allows the damping torque adjustment range to cover 50~500N. m, to improve the coupler's shock resistance and vibration reduction capabilities.

[0043] In some alternative embodiments, such as Figure 1 As shown, a cooling assembly is also fixedly connected to the outer wall of the housing 1. The cooling assembly includes heat dissipation fins 73 and a cooling channel 7 fixedly connected to the outer wall of the housing 1. An inlet pipe 71 and an outlet pipe 72 are connected to the cooling channel 7. Coolant is injected into the cooling channel 7 through the inlet pipe 71 and discharged through the outlet pipe 72, working with the heat dissipation fins 73 to quickly dissipate heat.

[0044] This invention also discloses a control method for a variable damping magnetohydrodynamic coupler, applied to a variable damping magnetohydrodynamic coupler for marine generator sets, such as... Figure 3 As shown, it includes the following steps: S1: Collect operating parameters of the variable damping magnetohydrodynamic coupler; Specifically, various operating parameters are collected through auxiliary sensing components. Radial displacement deviation δ r Data is collected by three piezoelectric ceramic integrated modules arranged circumferentially along the housing, with a sampling frequency of 1 kHz, a measurement range of ±0.02 mm, and an accuracy of ±0.001 mm. The output shaft speed ω is acquired by a speed sensor (model HCH3801), with a measurement range of 0~2000 r / min, and is converted to angular velocity ω in real time. The output shaft load torque M is acquired by a torque sensor (model JN338), with a measurement range of 0~1000 N. m. Damping cavity temperature T: acquired by a temperature sensor (model PT100) embedded in the inner wall of the housing, with a measurement range of 5~65℃.

[0045] In one specific embodiment, the method further includes preprocessing the collected operating parameters by employing a moving average filtering algorithm (window size 10) to eliminate high-frequency noise in the displacement and rotational speed signals. Temperature signals are then trend-predicted: if the temperature rise rate exceeds 5℃ / s within 10 seconds, it is marked as an abnormal temperature trend. Abnormal data exceeding reasonable ranges, such as δ... r >±0.02mm, ω>2000r / min, etc. After passing the self-test, set the initial operating parameters: excitation current I0=1A (corresponding to magnetic field strength B0=0.4T and damping torque Td0=200N·m at 25℃), displacement deviation threshold δ r0 =±0.005mm, reference speed ω0=1500r / min; if the self-test fails, an alarm signal will be triggered immediately, and the system will be prohibited from starting.

[0046] S2: Determine the operating condition level based on operating parameters; Specifically, when |δ r |≤δ r0 When |ω-ω0|≤ω1 and |M-M0|≤M1, ​​it is determined to be a steady working condition; When |δ r |>δ r0 And Vδ If ω1 ≤ V1, or ω2 ≥ |ω-ω0| > ω1, or M2 ≥ |M-M0| > M1, then it is determined to be the first level; When ω3≥|ω-ω0|>ω2 or M3≥|M-M0|>M2, it is determined to be the second level; When V δ If the value is >V1, or |ω-ω0|>ω3, or |M-M0|>M3, then it is determined to be the third level; Where, δ r δ represents the radial displacement deviation of the output shaft. r0 ω represents the displacement deviation threshold; ω is the output shaft speed, ω0 is the reference speed, ω1 is the first speed threshold, ω2 is the second speed threshold, ω3 is the third speed threshold, M is the load torque, M0 is the rated load torque, M1 is the first torque fluctuation threshold, M2 is the second torque fluctuation threshold, M3 is the third torque fluctuation threshold, and V is the displacement deviation threshold. δ V1 represents the rate of change of radial displacement deviation of the output shaft, and V1 is the threshold value for the rate of change of displacement deviation.

[0047] In one specific embodiment, the displacement deviation threshold δ r0 The reference speed ω0 is set to ±0.005 mm, the first speed threshold ω1 is set to 50 r / min, the second speed threshold ω2 is set to 100 r / min, the third speed threshold ω3 is set to 200 r / min, the rated load torque M0 is set to 764 N·m, the first torque fluctuation threshold M1 is set to 20 N·m, the second torque fluctuation threshold M2 is set to 30 N·m, the third torque fluctuation threshold M3 is set to 50 N·m, and the displacement deviation change rate threshold V1 is set to 0.001 mm / ms.

[0048] S3: Adjust the damping torque and / or radial displacement deviation compensation of the magnetorheological fluid according to the operating condition level to adjust the operating parameters to a stable operating condition.

[0049] Specifically, when the operating condition level is stable, the current operating parameters are maintained and continuously monitored; the current excitation current I0=1A and the piezoelectric element group has no compensation output are maintained, and the parameter reference is updated every 100ms to adapt to the slight drift of the unit during long-term operation.

[0050] When the operating condition level is Level 1, it is considered a slight fluctuation. The compensation amount for the radial displacement deviation is adjusted using the piezoelectric element group to restore the operating condition level to a stable level. Specifically, at Level 1, fine-tuning is prioritized using the piezoelectric element group. Based on the inverse piezoelectric effect of piezoelectric ceramics, the elastic deformation characteristics of the shaft system, and combined with error compensation theory, the compensation amount 's' for the radial displacement deviation of the output shaft and the radial displacement deviation δ of the output shaft are established. rThe piecewise mapping relationship of the output shaft speed ω avoids overcompensation and resonance under high-speed conditions, ensuring that the compensation amount accurately covers the deviation range. The control unit calls the piecewise mapping model to calculate the compensation amount s of the radial displacement deviation of the output shaft, as shown in Formula 1 below:

[0051] Where s is the compensation amount for the radial displacement deviation of the output shaft, K2 is the piezoelectric compensation coefficient, ω is the rotational speed of the output shaft, ω0 is the reference rotational speed, and δ r This represents the radial displacement deviation of the output shaft. This is the speed correction factor.

[0052] In one specific embodiment, K2 is 1.2. The value is set to 0.2, and ω0 is experimentally calibrated as 50π rad / s. When the output shaft speed is less than or equal to the reference speed, a fixed proportional compensation is used; when the output shaft speed is greater than the reference speed, the compensation ratio is reduced by a speed correction coefficient to avoid over-compensation at high speeds that could cause resonance, thus achieving rapid and accurate correction of small coaxial deviations under different operating speeds.

[0053] When the operating condition level is the second level, the compensation amount of radial displacement deviation is adjusted by the piezoelectric element group, and the damping torque of the magnetorheological fluid is adjusted by the excitation component, so that the operating condition level is restored to the stable operating condition level.

[0054] Specifically, when the operating condition level is level two, it is determined to be a moderate fluctuation. Fine-tuning of the piezoelectric element assembly and coarse-tuning of the excitation assembly are performed simultaneously. Fine-tuning of the piezoelectric element assembly calculates the compensation amount 's' according to the aforementioned formula and executes it to correct minor coaxial deviations. For coarse-tuning of the excitation assembly, the control unit calculates the damping torque of the magnetorheological fluid based on a multi-parameter mapping model. And the target excitation current I.

[0055] On the one hand, based on the Bingham rheological model of magnetorheological fluid, and combined with the structural parameters of the helical guide channel of the damping cavity and the dynamic characteristics of the shaft system, a multi-parameter quantitative relationship between the damping torque Td and the magnetic field strength B, the unit speed ω, and the load torque M is established. The core consideration is the synergistic effect of the viscous damping of the magnetorheological fluid, the shear damping induced by the magnetic field, and the additional damping of the load torque. Formula 2 is as follows: ; ; Using this model, the damping torque can be directly calculated from the magnetic field strength, rotational speed, and load. The system outputs a PWM signal to control the excitation coil current to the target excitation current I, thereby achieving precise matching and control of damping with the operating conditions. At the same time, the control adjustment step size is 0.1A to avoid impact caused by sudden current changes.

[0056] On the other hand, based on Ampere's circuital law, and combined with the magnetic reluctance loss of the magnetic ring, the skin effect of the excitation coil, and the experimental calibration of temperature loss, a corrected linear mapping relationship between the magnetic field strength B and the excitation current I and the unit temperature T is established to eliminate the influence of temperature on the accuracy of magnetic field regulation. Formula 3 is as follows: ; This model ensures that the linear adjustment accuracy of the current and magnetic field is ≤±3%, that is, for every 1A change in current, the magnetic field strength changes precisely by 0.4T (25℃ reference), and for every 1℃ deviation of temperature from the reference, the magnetic field strength is corrected by 0.08%, thus achieving stable and controllable adjustment of the magnetic field under different temperature conditions.

[0057] in Let ω be the damping torque of the magnetorheological fluid, R be the inner radius of the damping cavity, L be the axial length of the damping cavity, μ0 be the zero-magnetic-field viscosity of the magnetorheological fluid, and ω be the rotational speed of the output shaft. θ represents the shear yield strength of the magnetorheological fluid, in kPa; θ is the helix angle of the spiral guide channel; and M is the load torque. k is the load correction factor, k1 is the magnetic field coefficient, and k t I is the temperature correction factor, T is the excitation current, and T is the operating temperature inside the casing (unit: °C), with a value range of 5~65 °C.

[0058] In one specific embodiment, k1 is taken as 0.4T / A, k t The temperature was calibrated to 0.002 °C through high and low temperature experiments. R was set to 120 mm (0.12 m) and L to 80 mm (0.08 m). R and L are the core structural parameters of the damping cavity, determining the effective volume of the magnetorheological fluid. μ0 was set to 0.2 Pa·s, reflecting the basic damping characteristics without a magnetic field. θ was set to 30°, determining the flow path and shear stress state of the magnetorheological fluid. The experimental calibration was set to 0.05 to compensate for the additional effect of load changes on the damping torque.

[0059] When the operating condition level is the third level, it is determined to be an impact condition. The damping torque of the magnetorheological fluid is adjusted to the maximum by the excitation component, while the load is reduced.

[0060] Specifically, when the operating condition level is the third level, the emergency adjustment strategy is immediately triggered, the maximum excitation current is output, and the compensation amount s is corrected according to the real-time speed ω. The unit load is temporarily reduced by 10% to buffer the impact load and avoid damage to the shaft system.

[0061] In some optional embodiments, a fault warning is indicated and data is recorded when the following occurs in step S1: δ was collected in 3 consecutive samples rApproximately ±0.02mm; Temperature T is close to 65℃ or the rate of temperature rise within 10 seconds is >5℃ / s; The load torque M is close to 120% of the rated value.

[0062] In some optional embodiments, after completing step S3, feedback verification and secondary correction of the adjustment effect are performed. Specifically, data is collected at high speed using the piezoelectric element group and each auxiliary sensor at a sampling frequency of 2kHz, and fed back to the control unit for effect verification. After adjusting the first and second levels, if the operating parameters return to a stable operating condition, the adjustment is deemed effective, and the system switches to stable operating condition monitoring. If the parameters still exceed the threshold, the cause of the deviation is analyzed: if it is due to temperature changes, the excitation current I is corrected using formula three; if it is due to continuous load changes, the target damping torque is recalculated and the adjustment step size is adjusted to 0.05A for secondary adjustment.

[0063] After the adjustment of the third level is completed, δ is monitored within 20ms. r Check if the deviation returns to ≤0.008mm. If it does, reduce the current by 0.3A every 10ms and restore the load; if it does not, maintain the maximum excitation current and extend the load unloading time until the deviation meets the standard.

[0064] Furthermore, the number of secondary corrections within the same adjustment cycle (50ms) shall not exceed two to avoid system oscillations caused by frequent adjustments. When the adjustment effect is verified to be effective and no fault warnings are detected, the system enters steady-state operation mode. Every 500ms, the initial parameters (such as I0, δ) are checked. r0 It makes minor corrections to adapt to the cumulative drift of the unit operation; it outputs an operation status report every 10 seconds, including the current value of each parameter, the number of adjustments, and fault warning records; it continuously monitors temperature changes, and when the temperature deviates from 25℃ by more than 10℃, it corrects the excitation current in real time through Formula 3 to ensure the stability of the magnetic field strength and guarantee long-term operational reliability.

[0065] In one specific embodiment, the control unit integrates a signal acquisition module, a magnetic field damping mapping model module, a drive control module, and a fault diagnosis module. The signal acquisition module is electrically connected to the auxiliary sensing components and the piezoelectric element group, and is used to receive the operating parameters acquired by the auxiliary sensing components and the piezoelectric element group. The magnetic field damping mapping model module stores the excitation current control program. The excitation current control program outputs an excitation current control signal according to stored formulas two and three, thereby controlling the excitation current in the excitation coil to reach the target excitation current. The drive control module is electrically connected to the piezoelectric element group, and is used to store the piezoelectric element control program. The piezoelectric element control program outputs an output compensation control signal according to formula one, thereby controlling the piezoelectric element group to compensate for the set compensation amount of the output shaft radial displacement deviation. The fault diagnosis module is used to perform fault diagnosis.

[0066] Specifically, in steps S1 to S3, the control unit performs fault diagnosis on the monitoring data and adjustment process data in real time, such as... Figure 4 As shown: Component failure: If the linearity deviation of the piezoelectric element group is >±5%, the magnetic field deviation of the excitation component is >±10%, or the sensor signal is interrupted, it is determined to be a component failure. Immediately cut off the excitation current output, trigger the piezoelectric element group to lock the current position, output a fault alarm signal and record the fault code. Operational failure: δ r If the temperature T is greater than ±0.018 mm for 100 ms, the load M is greater than 65℃, and the load M is greater than 120% of the rated value, it is considered an operational fault. The emergency shutdown procedure should be initiated immediately, and the damping torque should be adjusted to the maximum to buffer the impact during the shutdown process. Fault memory and traceability: The control unit has a built-in fault memory module that records the time of fault occurrence, operating parameters, and adjustment process data, which facilitates later maintenance and troubleshooting.

[0067] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the entire control method of the variable damping magnetohydrodynamic coupler of this application will be described in detail below with reference to specific embodiments.

[0068] Step S0: Initial parameter setting. This embodiment is based on a 120kW marine safety-grade diesel generator set (model: 6135AZD). The supporting test equipment includes a six-degree-of-freedom marine working condition simulation vibration table (model: SDT-600), a high-precision shafting parameter testing system (sampling accuracy ±0.0001mm), and a magnetorheological fluid performance tester (model: MCR-302).

[0069] Generator set rated parameters: rated speed n0 = 1500 r / min (corresponding to angular velocity ω0 = 50π rad / s), rated power P0 = 120 kW, rated load torque M0 = 764 N·m. After system initialization, preset initial operating parameters are applied: initial excitation current I0 = 1 A (at 25℃, calibrated by a magnetorheological fluid performance tester, corresponding to magnetic field strength B0 = 0.4 T and damping torque Td0 = 200 N·m); displacement deviation threshold δ r0 =±0.005mm (set based on the alignment accuracy requirements of the shaft system of safety-grade equipment); piezoelectric compensation coefficient K2=1.2, speed correction coefficient =0.2 (all calibrated by high and low temperature tests); temperature correction factor k t =0.002 / ℃ (covering the unit's normal operating temperature range of 5~65℃); SPI bus communication baud rate 1Mbps, data transmission delay preset threshold ≤15ms.

[0070] S1. Acquire the operating parameters of the variable damping magnetohydrodynamic coupler. Simulate moderate turbulence conditions on a ship using a six-degree-of-freedom vibration table. According to GB / T10834-2019 "Vibration Test Method for Marine Diesel Generator Sets," set the vibration parameters as follows: turbulence frequency 10Hz, amplitude 5mm, vibration direction radially perpendicular to the shaft system, continuously acting on the generator set shaft system. After the system completes initialization self-test and enters the steady-state operation monitoring phase, each sensing component initiates synchronous data acquisition. The piezoelectric element group acquires the radial displacement deviation δ in real time at a sampling frequency of 1 kHz. r Data recordings show that within the initial 300ms, δ r The value rose steadily from 0.002 mm, reaching 0.008 mm after 300 ms, exceeding the preset threshold δ. 0 = ±0.005mm, and the calculated displacement rate V δ The reading is 0.00002 mm / ms (≤0.001 mm / ms, no impact characteristics). The speed sensor (model: HCH3801) collects the real-time speed n of the unit; the reading at 300ms is 1520 r / min, which is converted to an angular velocity ω≈50.67π rad / s, with a speed deviation |ω-ω0|=20 r / min (≤50 r / min). The torque sensor (model: JN338) collects the load torque M=775 N·m, with a load deviation |M-M0|=11 N·m (≤20 N·m). The temperature sensor (model: PT100) collects the unit's operating temperature T=32℃; the temperature rise rate within 10s is 0.3℃ / s, consistent with a normal temperature rise trend (no abnormal temperature warning). All collected data is processed by the control unit's built-in moving average filtering algorithm (window size 10) to eliminate high-frequency noise interference before being transmitted to the control unit's core module via the SPI bus. The measured data transmission delay is 12ms, lower than the preset threshold of 15ms.

[0071] S2, the control unit (FPGA+ARM dual-core architecture, model Xilinx Zynq-7020), after receiving preprocessed data, initiates hierarchical operating condition identification logic: first, it verifies the validity of each parameter (all within a reasonable range), and then compares it with the operating condition judgment threshold: current | δ r |>δ r0 But V δ ≤0.001mm / ms, |ω-ω0|≤50r / min, |M-M0|≤20N·m, T is normal, fully meeting the second-level conditions. Based on the preset adjustment strategy, the control unit decides to output adjustment commands: prioritize starting the piezoelectric element group to perform micro-compensation, temporarily not adjusting the excitation current, and setting the monitoring time after compensation to 5ms. If δ rIf the parameters are within the return threshold, the current parameters are maintained; if they are still exceeded, the magnetorheological damping fine-tuning is initiated, forming a step-by-step adjustment logic of "fine-tuning first, then coarse-tuning".

[0072] S3. Adjust the radial displacement deviation compensation amount s. The control unit calls the piezoelectric micro-compensation mapping model (Formula 1) and substitutes the real-time parameters to calculate the target compensation amount: Currently, ω=1520r / min>ω0=1500r / min, so a speed correction coefficient needs to be introduced. The calculation process is as follows:

[0073] Considering the driving accuracy of the piezoelectric element group (±0.0001mm), the compensation value is approximated to 0.0096mm, and the compensation direction is opposite to the radial displacement deviation direction (the displacement vector signal collected by the piezoelectric element group is determined to be in the positive X-axis direction, so the compensation direction is set to the negative X-axis direction). The control unit outputs a precise driving voltage signal (driving voltage 150V, meeting the rated driving requirements of the piezoelectric ceramic module) through the built-in D / A conversion module (16-bit accuracy). After power amplification, the signal is transmitted to the piezoelectric element group. The entire command calculation and output process takes 5ms, meeting the design requirement of response delay ≤20ms.

[0074] The control unit outputs a precise voltage signal (drive voltage 150V) to the piezoelectric element group via the drive module, triggering it to generate a micro-displacement compensation of 0.0096mm, with the compensation direction opposite to the radial displacement deviation direction. The entire command output process is delayed by 5ms to ensure rapid adjustment.

[0075] S4. Multi-dimensional feedback verification and steady-state maintenance of adjustment effect: After the compensation command is executed, the piezoelectric element group Where there is no conflict, the embodiments and features described above in this document can be combined with each other. Switching to high-speed sampling mode (sampling frequency increased to 2kHz), displacement deviation data is acquired synchronously; speed, load, and temperature sensors maintain real-time acquisition. After 5ms, feedback data shows: radial displacement deviation δ r The diameter decreased to 0.0025 mm, returning to the preset threshold δ. r0Within ±0.005mm, the displacement correction accuracy reaches 93.75%; the rotational speed is stable at 1518r / min, with a fluctuation range of ≤2r / min; the load is stable at 772N·m, with a fluctuation range of ≤3N·m; the temperature is maintained at 32℃ with no significant fluctuation. The control unit determines that the adjustment is effective through the effect verification module, and without initiating secondary correction, it immediately switches to steady-state operation mode: maintaining the current excitation current I0=1A, and correcting the theoretical value of the magnetic field strength every 500ms using temperature sensor data (current T=32℃, corrected theoretical value B=0.4T×(1-0.002×(32-25))=0.3944T, with a deviation from the measured magnetic field strength ≤±3%); outputting an operation status report every 10s through the RS485 interface, including the real-time values ​​of each parameter, the number of adjustments (this adjustment is counted as 1), and fault warning records (none); at the same time, shaft parameter drift monitoring is initiated, and the initial parameter reference is corrected in real time to ensure long-term operational stability.

[0076] This embodiment fully verifies the feasibility and superiority of the "priority piezoelectric fine-tuning under mild fluctuation conditions" coordinated adjustment strategy of the present invention by simulating moderate turbulence conditions on a ship. The key verification results are as follows: Regarding adjustment timeliness: The total time of the entire adjustment process (data acquisition - operating condition identification - command output - effect verification) is 32ms (300ms data acquisition + 12ms transmission + 5ms calculation output + 5ms feedback verification), which is far lower than the millisecond-level emergency response requirement (≤100ms) for safety-grade equipment; Regarding adjustment accuracy: The shaft coaxiality accuracy is restored from 0.008mm to 0.0025mm, with a correction accuracy of 93.75%, meeting the ±0.005mm alignment accuracy requirement of safety-grade generator sets; Regarding operational stability: After adjustment, the fluctuation range of speed, load, and temperature parameters are all controlled within the allowable range, with no secondary oscillations; Regarding adaptability: This adjustment strategy does not require the use of magnetorheological damping components, reducing energy consumption and component wear, and fully demonstrating the core advantage of "operating condition adaptable" adjustment. In summary, this invention can accurately adapt to the dynamic adjustment requirements of ships under moderate turbulence conditions, effectively improving the stability of shafting operation.

[0077] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A variable damping magnetohydrodynamic coupler for marine generator sets, characterized in that: It includes a housing, input shaft, output shaft, excitation assembly, control unit, piezoelectric element assembly, and auxiliary sensing assembly; A damping cavity is provided inside the housing; The excitation assembly includes a magnetorheological fluid, an excitation coil, and a magnetic ring. The magnetorheological fluid fills the damping cavity, the magnetic ring is fixedly connected to the side wall of the housing, the excitation coil is wound around the magnetic ring, and the excitation coil adjusts the magnetic field of the magnetic ring through the excitation current to control the damping torque of the magnetorheological fluid. The input shaft is rotatably connected to one end of the housing, and the output shaft is rotatably connected to the other end of the housing. A drive wheel is fixedly connected to one end of the input shaft that extends into the housing, and a driven wheel is fixedly connected to one end of the output shaft that extends into the housing. A clearance is provided between the drive wheel and the driven wheel. The auxiliary sensing component is used to collect the operating parameters of the coupler; The piezoelectric element group is connected to the outer wall of the input shaft and the output shaft, and is used to monitor the radial displacement deviation of the input shaft and the output shaft and to compensate for the radial displacement deviation; The control unit is electrically connected to the piezoelectric element group, the excitation coil, and the auxiliary sensing component, respectively, and is used to adjust the excitation current in the excitation coil and the driving voltage of the piezoelectric element group according to the operating parameters.

2. The variable damping magnetohydrodynamic coupler for marine generator sets according to claim 1, characterized in that, The piezoelectric element group includes multiple piezoelectric ceramics. Multiple piezoelectric ceramics are arranged circumferentially on the input shaft and the output shaft, respectively. One end of the piezoelectric ceramic is fixedly connected to the housing, and the other end of the piezoelectric ceramic is in contact with the outer wall of the input shaft or the output shaft.

3. The variable damping magnetohydrodynamic coupler for marine generator sets according to claim 1, characterized in that: The auxiliary sensing component includes: A speed sensor, connected to the input shaft and the output shaft, is used to collect the speed information of the input shaft and the output shaft respectively; A load sensor, connected to the output shaft, is used to monitor the load torque information of the output shaft; A temperature sensor is connected inside the housing to monitor the operating temperature inside the housing.

4. The variable damping magnetohydrodynamic coupler for marine generator sets according to claim 1, characterized in that: Sealing rings are connected between the housing and the input shaft, and between the housing and the output shaft, respectively.

5. The variable damping magnetohydrodynamic coupler for marine generator sets according to claim 1, characterized in that, The inner wall of the damping cavity is provided with a spiral guide groove.

6. A control method for a variable damping magnetohydrodynamic coupler, applied to the variable damping magnetohydrodynamic coupler for marine generator sets as described in any one of claims 1-5, characterized in that, include: Collect operating parameters of the variable damping magnetohydrodynamic coupler; The operating condition level is determined based on the aforementioned operating parameters; Adjust the damping torque and / or radial displacement deviation compensation of the magnetorheological fluid according to the operating condition level to bring the operating parameters to a stable operating condition.

7. The control method for the variable damping magnetohydrodynamic coupler according to claim 6, characterized in that, The operating parameters include load torque information, input shaft and output shaft speed information, radial displacement deviation of input shaft and output shaft, and operating temperature information inside the housing; The determination is based on a comparison between the operating parameters and the set parameter thresholds, including: When |δ r |≤δ r0 When |ω-ω0|≤ω1 and |M-M0|≤M1, ​​it is determined to be a steady working condition; When |δ r |>δ r0 And V δ If ω1 ≤ V1, or ω2 ≥ |ω-ω0| > ω1, or M2 ≥ |M-M0| > M1, then it is determined to be the first level; When ω3≥|ω-ω0|>ω2 or M3≥|M-M0|>M2, it is determined to be the second level; When V δ If the value is >V1, or |ω-ω0|>ω3, or |M-M0|>M3, then it is determined to be the third level; Where, δ r δ represents the radial displacement deviation of the output shaft. r0 ω represents the displacement deviation threshold; ω is the output shaft speed, ω0 is the reference speed, ω1 is the first speed threshold, ω2 is the second speed threshold, ω3 is the third speed threshold, M is the load torque, M0 is the rated load torque, M1 is the first torque fluctuation threshold, M2 is the second torque fluctuation threshold, M3 is the third torque fluctuation threshold, and V is the displacement deviation threshold. δ V1 represents the rate of change of radial displacement deviation of the output shaft, and V1 is the threshold value for the rate of change of displacement deviation.

8. The control method for the variable damping magnetohydrodynamic coupler according to claim 7, characterized in that: The step of adjusting the damping torque and / or radial displacement deviation compensation of the magnetorheological fluid according to the operating condition level to adjust the operating parameters to a stable operating condition includes: When the operating condition level is stable, maintain the current operating parameters and continue monitoring; When the operating condition level is the first level, the compensation amount of radial displacement deviation is adjusted by the piezoelectric element group to restore the operating condition level to the stable operating condition level. When the operating condition level is the second level, the compensation amount of radial displacement deviation is adjusted by the piezoelectric element group, and the damping torque of the magnetorheological fluid is adjusted by the excitation component, so that the operating condition level is restored to the stable operating condition level. When the operating condition level is the third level, the damping torque of the magnetorheological fluid is adjusted to the maximum through the excitation component, while the load is reduced.

9. The control method for the variable damping magnetohydrodynamic coupler according to claim 8, characterized in that, The method for adjusting the compensation amount of radial displacement deviation using a piezoelectric element assembly is as follows: Where s is the compensation amount for the radial displacement deviation of the output shaft, K2 is the piezoelectric compensation coefficient, ω is the rotational speed of the output shaft, ω0 is the reference rotational speed, and δ r This represents the radial displacement deviation of the output shaft. This is the speed correction factor.

10. The control method for the variable damping magnetohydrodynamic coupler according to claim 8, characterized in that, The method for adjusting the damping torque of the magnetorheological fluid through the excitation assembly is as follows: ； ； ； in Let ω be the damping torque of the magnetorheological fluid, R be the inner radius of the damping cavity, L be the axial length of the damping cavity, μ0 be the zero-magnetic-field viscosity of the magnetorheological fluid, and ω be the rotational speed of the output shaft. Let θ be the shear yield strength of the magnetorheological fluid, θ be the helix angle of the spiral guide channel, and M be the load torque. k is the load correction factor, k1 is the magnetic field coefficient, and k t Where I is the temperature correction factor, I is the excitation current, and T is the operating temperature inside the casing.

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