A large blade active-passive dual damping clamp based on magneto-rheological effect and collaborative control method

Abstract

The application discloses a large-blade active-passive double-vibration-reducing clamp based on a magneto-rheological effect and a cooperative control method, belongs to the field of mechanical processing vibration control, and is used for inhibiting multi-modal coupling self-excitation and forced vibration in milling of large flexible components such as steam turbine blades. The system is respectively provided with independent active-passive magneto-rheological vibration-reducing clamps at the blade tip and the blade root, each clamp is integrated with a magneto-rheological liquid vibration-reducing cavity and a wireless vibration sensor, and is uniformly regulated and controlled by a central cooperative controller. The controller adopts a fuzzy self-adaptive cooperative control algorithm, fuses blade root and blade tip vibration signals in real time, intelligently identifies blade overall vibration modes and key resonance frequencies, dynamically decides and outputs two independent and cooperative optimized current instructions, and makes the magneto-rheological liquid generate a fast-adjustable self-adaptive damping. The method realizes precise active control on blade broadband multi-modal vibration through active-passive fusion, double-position cooperation and intelligent targeted inhibition, and significantly improves processing stability, surface quality and production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of vibration control technology in machining, specifically relating to a dual active and passive vibration damping fixture and its coordinated control method used in milling, grinding, and other machining processes of large flexible components such as turbine blades. It is particularly suitable for vibration suppression during precision machining of weakly rigid, long cantilever blades on a five-axis machine tool. Background Technology

[0002] With the rapid development of clean energy and the aerospace industry, the size of turbine blades is constantly increasing, and their flexibility is becoming more and more pronounced. These blades are usually clamped in a cantilever manner on equipment such as five-axis machine tools, and are typical "weakly rigid" workpieces. During the cutting process, the periodic cutting force can easily cause high-frequency chatter or low-frequency large-amplitude vibration of the workpiece, leading to a series of machining problems: chatter marks appear on the machined surface, affecting surface quality; geometric accuracy is difficult to guarantee, especially the blade profile accuracy; tool wear is accelerated, shortening tool life; to avoid vibration, cutting parameters usually need to be reduced, resulting in low machining efficiency.

[0003] Currently, the industry commonly uses passive damping methods, such as incorporating oil cavities or filling viscoelastic materials within the fixture, to dissipate vibration energy. However, the damping characteristics of these passive damping methods are fixed after manufacturing and cannot be dynamically adjusted according to machining conditions. The vibration characteristics of blades change dynamically with factors such as machining position, cutting parameters, and tool condition. Fixed damping is difficult to adapt to varying working conditions, often being effective under one condition but having minimal effect under another. Furthermore, large blades, as long cantilever beam structures, exhibit complex vibration modes, with significant amplitude and phase differences often existing between the blade tip and root. Traditional single-point damping methods struggle to effectively suppress modal vibrations of different parts and orders of the blade simultaneously. Currently, there is a lack of a vibration damping fixture system that can be simultaneously deployed at critical blade locations such as the blade tip and root, and can perform coordinated intelligent control based on the overall vibration state of the blade. Therefore, developing an intelligent vibration damping fixture capable of real-time vibration sensing, actively adjusting damping characteristics, and achieving multi-position coordinated control has become crucial for solving the vibration control challenges in large blade machining. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing vibration damping fixtures and to provide a magnetorheological active and passive dual vibration damping fixture and a collaborative control method that acts on the blade tip and blade root respectively.

[0005] To solve the technical problem, the solution of the present invention is:

[0006] A dual active and passive vibration damping fixture for large blades based on magnetorheological effect is characterized by comprising: an active and passive vibration damping fixture at the blade tip, an active and passive vibration damping fixture at the blade root, and a central coordinating controller. The three components constitute an active and passive coordinating control system. Both the active and passive vibration damping fixtures at the blade tip and the blade root are equipped with vibration sensors for real-time monitoring of the vibration state of the corresponding parts. The central coordinating controller generates and outputs two independent control commands based on the vibration signals from the blade tip and the blade root, enabling the blade tip and blade root fixtures to achieve synchronous and coordinated adaptive vibration damping.

[0007] Furthermore, the base of the blade tip active and passive vibration damping fixture is rigidly connected to the clamping device via a lead screw, forming a high-rigidity clamping structure, which significantly improves the contact rigidity of the fixture and the blade mating surface. A lower pad is laid at the bottom of the base, a damping cavity is placed on the lower pad, an upper pad is laid on the damping cavity, and a top plate is installed on the upper pad. The top plate and the base are connected by a high-preload threaded connection, further enhancing the overall structural rigidity. The damping cavity is fixed by two semi-cross fixing bodies on the bottom plate, and the top plate has two blind holes for positioning. The damping cavity is filled with… The magnetorheological fluid contains four cylindrical magnets with coils wound around their exteriors. The damping cavity contains 160 ceramic spheres with built-in magnetic particles as passive damping elements. A mesh structure made of high-permeability material is also present within the damping cavity 5, distributed between the cylindrical magnets 9 and the ceramic spheres 11. This mesh structure guides the uniform distribution of the magnetic field and increases the flow damping of the magnetorheological fluid. The coils are connected to a controllable power supply; by adjusting the current, the magnetic field strength is changed, thereby controlling the rheological characteristics of the magnetorheological fluid and achieving a combined active and passive damping function.

[0008] Furthermore, the base of the blade root active and passive vibration damping fixture is rigidly connected to the clamping device via a screw, forming a high-rigidity clamping structure to ensure the stability of the blade root clamping and the rigidity of the mating surface. The base has a lower shim at the bottom, two damping cavities are placed side-by-side on the lower shim, an upper shim is placed on top of the damping cavities, and a top plate is installed on the upper shim. The top plate and the base are connected by a high-preload threaded connection, forming a multi-layered composite high-rigidity structure. The damping cavities are fixed by two semi-cross-shaped fixing bodies on the bottom plate. The top plate has two blind holes for positioning. The interior of the damping cavities... The device is filled with magnetorheological fluid, in which four cylindrical magnets are installed. Coils are wound around the outside of the cylindrical magnets. The damping cavity is equipped with 160 ceramic balls with built-in magnetic particles as passive damping elements. The damping cavity 5 is also equipped with a mesh structure made of high magnetic permeability material, which is distributed between the cylindrical magnets 9 and the ceramic balls 11. The mesh structure is used to guide the uniform distribution of the magnetic field and increase the flow damping of the magnetorheological fluid. The coils are connected to a controllable power supply. By adjusting the current, the magnetic field strength is changed, thereby controlling the rheological characteristics of the magnetorheological fluid and realizing the combined active and passive damping function.

[0009] Furthermore, the vibration sensor is a multi-sensor fusion unit, comprising a combination of accelerometers, displacement sensors, and force sensors, used to comprehensively monitor the blade vibration state from multiple physical dimensions. The vibration sensor is connected to a central coordinating controller and a controllable power supply. The central coordinating controller has a built-in fuzzy adaptive control algorithm, capable of fusing multi-source sensor information and collaboratively generating and outputting two independent control currents based on the vibration signals at the blade tip and root positions. Furthermore, the blade tip active and passive vibration damping fixtures and the blade root active and passive vibration damping fixtures are made of rigid materials, and the damping chambers employ a sealed design to prevent magnetorheological fluid leakage.

[0010] Furthermore, the blade tip active and passive vibration damping fixture and the blade root active and passive vibration damping fixture are made of high-strength rigid materials, and the vibration damping cavity adopts a multi-seal structure design, including sealing rings, sealant and anti-leakage overflow structure, to ensure zero leakage of magnetorheological fluid under high-frequency vibration and high-pressure conditions, and to ensure the reliability and safety of long-term use.

[0011] A collaborative control method for a large blade active and passive dual vibration damping fixture based on magnetorheological effect includes the following steps:

[0012] Step 1: First, lay the lower shim on the base, ensuring it is precisely positioned between the semi-cross fixing bodies to form a bottom buffer and stiffness matching layer. Then, install the vibration damping cavity between each pair of semi-cross fixing bodies, achieving precise positioning and rigid fixation of the vibration damping cavity through the semi-cross fixing bodies. Next, lay the shim on top of the vibration damping cavity to form an upper buffer and stiffness matching layer. Finally, install the top plate onto the base using a high preload threaded structure, achieving precise alignment through blind holes on the top plate to complete the sealing and pre-compression of the vibration damping cavity. The lead screw installed on the base, combined with the clamping device, forms an adjustable high-rigidity clamping interface.

[0013] Step 2: A mesh structure made of high magnetic permeability material is pre-installed inside the vibration damping cavity and distributed throughout the cavity. Then, four cylindrical magnets with coils wound around them are installed throughout the cavity, ensuring that the magnets and mesh structure are spatially staggered. Next, magnetorheological fluid is injected into the cavity, and 160 ceramic spheres with built-in magnetic particles are distributed to form a solid-liquid-magnetic-mesh composite damping system.

[0014] Step 3: Monitor the vibration signal of the large blade in real time under clamping conditions using a vibration sensor;

[0015] Step 4: The central coordinating controller receives the vibration signal and calculates its vibration amplitude and spectral characteristics;

[0016] Step 5: The central coordinating controller compares the calculated vibration characteristic quantities with the preset thresholds and generates control commands based on the preset fuzzy adaptive coordinating control algorithm;

[0017] Step Six: The control command drives the controllable power supply to output the corresponding current to the coil;

[0018] Step 7: The coil generates a magnetic field of corresponding strength, causing an instantaneous change in the apparent viscosity and shear yield stress of the magnetorheological fluid in the damping cavity. At the same time, the magnetic field interacts with the ceramic spheres with built-in magnetic particles and the mesh structure through multiple coupling effects. The damping effect is enhanced through multiple mechanisms such as fluid resistance enhancement, magnetic circuit guidance and magneto-solid coupling, thereby adjusting the overall damping force of the fixture and suppressing the vibration of the large blade.

[0019] Furthermore, the aforementioned method for coordinated control of large blade active and passive dual vibration damping fixtures based on magnetorheological effect is characterized by including the following steps:

[0020] S1. Vibration signals at the blade tip and blade root positions are collected synchronously using vibration sensors on the blade tip clamp and blade root clamp, respectively;

[0021] S2. The central coordinating controller receives the two vibration signals and comprehensively analyzes the overall vibration mode of the blade, as well as the phase and amplitude relationship of the vibration at the blade tip and root.

[0022] S3. The central coordinating controller calculates the first control current I1 and the second control current I2 required to drive the electromagnetic coils of the blade tip clamp and the blade root clamp according to the preset coordinating control strategy, wherein the coordinating control strategy is designed to enable the damping forces generated by the two clamps to coordinating and suppress the overall vibration of the blade.

[0023] S4. The central coordinating controller synchronously outputs the first control current I1 to the electromagnetic coil of the blade tip clamp and outputs the second control current I2 to the electromagnetic coil of the blade root clamp.

[0024] S5. Under the influence of their respective magnetic fields, the state of the magnetorheological fluid inside the blade tip clamp and the blade root clamp changes independently, thereby generating independently adjustable and mutually synergistic damping forces at the blade tip and root, which together suppress processing vibration.

[0025] Furthermore, the large blade active and passive dual vibration damping clamp collaborative control method based on magnetorheological effect is characterized in that the dynamic selection of collaborative control strategy in step S3 includes: when the main vibration frequencies of the blade tip and blade root are similar and lower than the first threshold, a same-frequency targeting collaborative strategy is adopted, with the main frequency of the one with greater vibration energy as the common target frequency, and the phase of the dual control current is compensated according to the phase difference; when the difference between the main vibration frequencies of the blade tip and blade root is greater than the second threshold, a different-frequency independent targeting strategy is adopted, with the blade tip and blade root controllers respectively using their respective main vibration frequencies as target frequencies for independent fuzzy control; when the vibration energy at one point of the blade tip or blade root is significantly greater than that at another point, a master-slave enhancement strategy is adopted, with the high-energy position as the master control point for active suppression, and the other position as the slave control point to provide coupling auxiliary damping.

[0026] Furthermore, the large blade active and passive dual vibration damping fixture cooperative control method based on magnetorheological effect is characterized in that the fuzzy adaptive cooperative control algorithm in step S3 includes the following steps:

[0027] a) Fuzzification: The vibration features extracted in step S2, including vibration amplitude error, error change rate and frequency matching degree, are mapped into fuzzy linguistic variables;

[0028] b) Fuzzy reasoning: Based on a preset fuzzy rule base, reason about the fuzzified input variables to obtain the fuzzy set of output variables—control current increments;

[0029] c) Defuzzification: Convert the fuzzy set of the output variables into precise control current increment values;

[0030] d) Adaptive parameter update: Based on the vibration suppression effect within a control cycle, adjust the weights of some rules in the fuzzy rule base or the fuzzification and defuzzification parameters online to optimize the subsequent control effect.

[0031] Furthermore, the large blade active and passive dual vibration damping fixture collaborative control method based on magnetorheological effect is characterized in that, in step S3, the central collaborative controller also performs dynamic weight allocation based on the tool spatial attitude: the system calculates the energy ratio R between the vibration signals of the blade tip and the blade root in real time. E The method infers the approximate machining area of ​​the tool on the blade and dynamically allocates the control weights and strategies of the two vibration damping fixtures accordingly: when the tool is in the blade tip region, the active control of the blade tip fixture is dominant, with the blade root fixture providing assistance; when the tool moves to the middle of the blade, the two fixtures work in a balanced and coordinated manner to jointly suppress coupled vibrations; when the tool approaches the blade root, the high-precision control of the blade root fixture takes precedence. The control strategies between each region are seamlessly switched using a smooth transition algorithm, ensuring the continuity and stability of vibration suppression throughout the entire tool travel. This method enables the vibration damping system to adapt to dynamic changes in the machining position, always maintaining optimal vibration suppression performance.

[0032] Furthermore, the large blade active and passive dual vibration damping fixture collaborative control method based on magnetorheological effect is characterized in that, in step S3, the central collaborative controller switches different active and passive control modes according to the frequency band to which the identified main vibration frequency belongs: in the low frequency band, an active control-dominant mode is adopted, outputting a larger control current; in the mid frequency band, an active and passive combined mode is adopted, superimposing an active tuning current on the basic passive damping current; in the high frequency band, a passive control-dominant mode is adopted, outputting a stable basic damping current.

[0033] Furthermore, the aforementioned collaborative control method for large blade active and passive dual vibration damping clamps based on magnetorheological effect is characterized by the following: the collaborative control algorithm is a collaborative control algorithm based on fuzzy adaptive control. This algorithm runs in a central collaborative controller and can select a global vibration suppression mode or a specific frequency targeted suppression mode according to the real-time spectral changes of the vibration signals from the blade tip and root, and achieve optimized distribution of damping forces at both positions through a collaborative strategy. It can receive vibration signals from the blade tip clamp and the blade root clamp, perform joint spectral analysis and modal identification, and generate two independent control current commands according to a preset collaborative strategy to drive the magnetorheological dampers at the blade tip and root respectively, thereby achieving collaborative suppression of the overall blade vibration. The algorithm has online self-learning capabilities and can optimize parameters based on historical control effects.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] This invention utilizes the controllable rheological properties of magnetorheological fluid, combined with a fuzzy adaptive collaborative control algorithm, to dynamically adjust two control currents based on real-time acquired vibration signals from the blade tip and root, achieving stepless adjustment of the damping force. This overcomes the shortcomings of traditional passive vibration damping fixtures, which have fixed damping and cannot adapt to dynamic processing conditions, significantly improving the real-time performance and adaptability of vibration suppression, and realizing intelligent adaptive suppression of blade vibration.

[0036] This invention proposes a dual-position collaborative vibration suppression mechanism that effectively covers the overall vibration modes of the blade. By arranging independent sensing and actuation units at the blade tip and root respectively, the system can simultaneously capture and suppress vibration modes of different parts and orders of the blade. The central collaborative controller intelligently allocates damping forces at the two locations based on the vibration phase, amplitude, and frequency characteristics, achieving collaborative control of the overall blade vibration and solving the industry problem of limited single-point vibration reduction range.

[0037] This invention features a multi-mode switchable collaborative control strategy to adapt to complex machining conditions. The system supports various collaborative control strategies, such as same-frequency targeted collaboration, different-frequency independent targeting, and master-slave enhancement, and can dynamically allocate control weights according to the tool position. The controller can also intelligently switch between active and passive control modes based on the frequency band of the identified dominant vibration frequency, achieving optimal vibration suppression across the entire frequency band and process.

[0038] This invention integrates active and passive damping mechanisms, possessing both high stability and rapid response capabilities. Ceramic spheres with magnetic particles are placed in the damping cavity as passive damping elements, combined with the active, controllable damping of magnetorheological fluid, forming a composite active-passive damping structure of "passive basic damping + active tuned damping." The clamp body adopts a rigid sealing design, ensuring clamping stability and leak-proof reliability while achieving millisecond-level magnetic field response and damping adjustment.

[0039] This invention improves machining quality and efficiency, has good engineering applicability, significantly reduces chatter and vibration amplitude during machining, effectively suppresses surface ripples, ensures blade profile accuracy, and extends tool life. The system allows stable machining under higher cutting parameters, thereby improving machining efficiency, and is particularly suitable for precision machining of large flexible components such as wind turbine blades and steam turbine blades.

[0040] The system of this invention has high reliability and a certain degree of redundancy. The dual-clamp system constitutes a certain degree of redundancy design. When a single clamp experiences performance degradation or temporary failure, the system can still maintain a basic vibration reduction effect by adjusting the control strategy and using the other clamp, thereby improving the reliability and robustness of the entire machining system. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the active and passive dual vibration damping fixture and control system for large blades described in this invention;

[0042] Figure 2 Schematic diagram of a magnetorheological active and passive vibration damping fixture for blade tips;

[0043] Figure 3 Cross-sectional view of the magnetorheological active and passive vibration damping fixture for blade tips; Figure 4 Schematic diagram of a magnetorheological active and passive vibration damping fixture for leaf roots; Figure 5 Cross-sectional view of the blade root magnetorheological active and passive vibration damping fixture;

[0044] Figure 6 The flowchart shows the active and passive vibration reduction control method for a single clamp on a large blade based on magnetorheological effect.

[0045] Figure 7 A flowchart of a collaborative control method for active and passive dual vibration damping fixtures for large blades based on magnetorheological effect;

[0046] Figure 8 This is a schematic diagram of the fuzzy adaptive collaborative control method for a large blade active and passive dual vibration damping fixture.

[0047] Among them, 1 is the base, 2 is the lead screw, 3 is the clamping device, 4 is the lower pad, 5 is the vibration damping cavity, 6 is the upper pad, 7 is the top plate, 8 is the magnetorheological fluid, 9 is the cylindrical magnet, 10 is the coil, 11 is the ceramic ball, 12 is the semi-cross fixing body, 14 is the central coordinating controller, 16 is the blade root vibration damping fixture, 17 is the large blade, 18 is the blade tip vibration damping fixture, 19 is the cutting tool, and 20 is the main spindle. Detailed Implementation

[0048] The following description, in conjunction with the accompanying drawings and specific embodiments, further explains the active and passive dual vibration damping fixture and collaborative control method for large blades based on magnetorheological effects provided by the present invention. However, the present invention is not limited to the following embodiments.

[0049] Specific Embodiment 1: A dual active and passive vibration damping clamp system for large blades based on magnetorheological effect, comprising a blade tip active and passive vibration damping clamp 18, a blade root active and passive vibration damping clamp 16, and a central coordinating controller 14, which together constitute an active and passive coordinating control system. The base 1 of the bases of the blade tip active and passive vibration damping clamp 18 and the blade root active and passive vibration damping clamp 16 is rigidly connected to the clamping device 3 via a lead screw 2, forming a high-rigidity clamping structure, significantly improving the contact stiffness of the clamp and the blade mating surface. A lower pad 4 is laid at the bottom of the base 1, and a vibration damping cavity 5 is placed on top of the lower pad 4. The blade tip active and passive vibration damping clamp 18 has one vibration damping cavity, and the blade root active and passive vibration damping clamp 16 has two vibration damping cavities. An upper pad 6 is laid on top of the vibration damping cavity 5, and a top plate 7 is installed on the upper pad 6. The top plate 7 is connected to the base 1 via a high-preload threaded connection. To further enhance the overall structural rigidity, the vibration damping cavity 5 is fixed by two semi-cross-shaped fixing bodies 12 on the bottom plate. The top plate 7 has two blind holes for positioning. The vibration damping cavity 5 is filled with magnetorheological fluid 8, and four cylindrical magnets 9 are installed in the magnetorheological fluid 8. Coils 10 are wound around the outside of the cylindrical magnets 9. The vibration damping cavity 5 is equipped with 160 ceramic balls 11 with built-in magnetic particles as passive damping elements. The coils 10 are connected to a controllable power supply 15. By adjusting the current, the magnetic field strength is changed, thereby controlling the rheological characteristics of the magnetorheological fluid 8 to achieve a combined active and passive vibration damping function. To further enhance energy dissipation under low-frequency, large-amplitude vibrations, a layer of porous metal mesh is added near the cavity wall inside the vibration damping cavity 5. The metal mesh interacts with the magnetic field generated by the electromagnetic coil 10 to form auxiliary magnetic poles, enabling the magnetorheological fluid 8 near the cavity wall to generate high yield stress even at low current. This improves the basic damping performance of the clamp without significantly increasing energy consumption. Both the blade tip and blade root active and passive vibration damping clamps are equipped with vibration sensors 13 for real-time monitoring of the vibration state of the corresponding parts. The central coordinating controller 14 generates and outputs two independent control commands based on the vibration signals from the blade tip and blade root, enabling the blade tip and blade root clamps to achieve synchronous and coordinated adaptive vibration damping. The vibration sensor 13 is a multi-sensor fusion unit, including a combination of acceleration sensors, displacement sensors, and force sensors, used to comprehensively monitor the blade vibration state from multiple physical dimensions. The vibration sensor 13 is connected to the central coordinating controller 14 and the controllable power supply 15. The central coordinating controller 14 has a built-in fuzzy adaptive control algorithm that can fuse multi-source sensor information and generate and output two independent control currents based on the vibration signals from the blade tip and blade root positions. The blade tip active and passive vibration damping fixture 18 and the blade root active and passive vibration damping fixture 16 are made of high-strength rigid materials. The vibration damping cavity 5 adopts a multi-seal structure design, including sealing rings, sealant and anti-leakage overflow structure, to ensure zero leakage of magnetorheological fluid 8 under high-frequency vibration and high-pressure conditions, and to ensure the reliability and safety of long-term use.

[0050] This example demonstrates a dual active and passive vibration damping fixture for large blades based on magnetorheological effects, comprising the following steps:

[0051] Step 1: First, lay the lower shim 4 on the base 1, ensuring that the lower shim 4 is precisely positioned between the semi-cross fixing bodies 11 to form a bottom buffer and stiffness matching layer; then, install the vibration damping cavity 5 between each pair of semi-cross fixing bodies 12, achieving precise positioning and rigid fixation of the vibration damping cavity 5 through the semi-cross fixing bodies 12; next, lay the upper shim 6 on the vibration damping cavity 5 to form an upper buffer and stiffness matching layer; finally, install the top plate 7 on the base 1 through a high preload threaded structure, and achieve precise alignment through the blind holes on the top plate 7 to complete the sealing and pre-compression of the vibration damping cavity 5; the lead screw 2 installed on the base is combined with the clamping device 3 to form an adjustable high-rigidity clamping interface;

[0052] Step 2: A mesh structure made of high magnetic permeability material is pre-installed inside the damping cavity 5 and distributed within the internal space of the damping cavity; then, four cylindrical magnets 9 with coils 10 wound around them are installed throughout the entire damping cavity 5, ensuring that the cylindrical magnets 9 and the mesh structure are arranged in a spatially staggered manner; next, magnetorheological fluid 8 is injected into the damping cavity 5, and 160 ceramic balls 11 with built-in magnetic particles are distributed to form a solid-liquid-magnetic-mesh composite damping system;

[0053] Step 3: Monitor the vibration signal of the large blade in real time under clamping conditions using vibration sensor 13;

[0054] Step 4: The central coordinating controller 14 receives the vibration signal and calculates its vibration amplitude and spectral characteristics;

[0055] Step 5: The central coordinating controller 14 compares the calculated vibration characteristic quantity with the preset threshold, and generates control commands according to the preset fuzzy adaptive coordinating control algorithm;

[0056] Step 6: The control command drives the controllable power supply 15 to output the corresponding current to the coil 10;

[0057] Step 7: The coil 10 generates a magnetic field of corresponding strength, causing an instantaneous change in the apparent viscosity and shear yield stress of the magnetorheological fluid 8 in the damping cavity 5. At the same time, the magnetic field interacts with the ceramic ball 11 with built-in magnetic particles and the mesh structure through multiple coupling effects. The damping effect is enhanced through multiple mechanisms such as fluid resistance enhancement, magnetic circuit guidance and magneto-solid coupling, thereby adjusting the overall damping force of the fixture and suppressing the vibration of the large blade.

[0058] Specific Implementation Example 2: A collaborative control method for a large blade active and passive dual vibration damping fixture based on magnetorheological effect, comprising the following steps:

[0059] S1. Vibration signals at the blade tip and blade root positions are collected synchronously using vibration sensors on the blade tip clamp and blade root clamp, respectively;

[0060] S2. The central coordinating controller receives the two vibration signals and comprehensively analyzes the overall vibration mode of the blade, as well as the phase and amplitude relationship of the vibration at the blade tip and root.

[0061] S3. The central coordinating controller calculates the first control current I1 and the second control current I2 required to drive the electromagnetic coils of the blade tip clamp and the blade root clamp according to the preset coordinating control strategy, wherein the coordinating control strategy is designed to enable the damping forces generated by the two clamps to coordinating and suppress the overall vibration of the blade.

[0062] S4. The central coordinating controller synchronously outputs the first control current I1 to the electromagnetic coil of the blade tip clamp and outputs the second control current I2 to the electromagnetic coil of the blade root clamp.

[0063] S5. Under the influence of their respective magnetic fields, the state of the magnetorheological fluid inside the blade tip clamp and the blade root clamp changes independently, thereby generating independently adjustable and mutually synergistic damping forces at the blade tip and root, which together suppress processing vibration.

[0064] In this example, the dynamic selection of the cooperative control strategy in step S3 includes: when the main vibration frequencies of the blade tip and the blade root are similar and lower than the first threshold, a same-frequency targeting cooperative strategy is adopted, with the main frequency of the one with greater vibration energy as the common target frequency, and the phase of the dual-path control current is compensated according to the phase difference; when the difference between the main vibration frequencies of the blade tip and the blade root is greater than the second threshold, a different-frequency independent targeting strategy is adopted, with the blade tip and blade root controllers using their respective main vibration frequencies as the target frequencies for independent fuzzy control; when the vibration energy at one location, the blade tip or the blade root, is significantly greater than that at another location, a master-slave enhancement strategy is adopted, with the high-energy location as the master control point for active suppression, and the other location as the slave control point to provide coupling auxiliary damping.

[0065] In this example, the fuzzy adaptive cooperative control algorithm described in step S3 includes the following steps:

[0066] a) Fuzzification: The vibration features extracted in step S2, including vibration amplitude error, error change rate and frequency matching degree, are mapped into fuzzy linguistic variables;

[0067] b) Fuzzy reasoning: Based on a preset fuzzy rule base, reason about the fuzzified input variables to obtain the fuzzy set of output variables—control current increments;

[0068] c) Defuzzification: Convert the fuzzy set of the output variables into precise control current increment values;

[0069] d) Adaptive parameter update: Based on the vibration suppression effect within a control cycle, adjust the weights of some rules in the fuzzy rule base or the fuzzification and defuzzification parameters online to optimize the subsequent control effect.

[0070] In this example, the central coordinating controller mentioned in step S3 also performs dynamic weight allocation based on the tool space attitude: the system calculates the energy ratio R between the blade tip and blade root vibration signals in real time. E The method infers the approximate machining area of ​​the tool on the blade and dynamically allocates the control weights and strategies of the two vibration damping fixtures accordingly: when the tool is in the blade tip region, the active control of the blade tip fixture is dominant, with the blade root fixture providing assistance; when the tool moves to the middle of the blade, the two fixtures work in a balanced and coordinated manner to jointly suppress coupled vibrations; when the tool approaches the blade root, the high-precision control of the blade root fixture takes precedence. The control strategies between each region are seamlessly switched using a smooth transition algorithm, ensuring the continuity and stability of vibration suppression throughout the entire tool travel. This method enables the vibration damping system to adapt to dynamic changes in the machining position, always maintaining optimal vibration suppression performance.

[0071] In this example, the central coordinating controller in step S3 switches between different active and passive control modes according to the frequency band to which the identified main oscillation frequency belongs: in the low frequency band, the active control mode is adopted, and a larger control current is output; in the mid frequency band, the active and passive combined mode is adopted, and the active tuning current is superimposed on the basic passive damping current; in the high frequency band, the passive control mode is adopted, and a stable basic damping current is output.

[0072] This example illustrates a collaborative control method for a large blade's active and passive dual vibration damping clamp based on magnetorheological effects. The key feature is that the collaborative control algorithm is a fuzzy adaptive control-based algorithm running in a central collaborative controller. This algorithm can select a global vibration suppression mode or a specific frequency targeted suppression mode based on the real-time spectral changes of the vibration signals from the blade tip and root, and optimize the distribution of damping forces at both positions through a collaborative strategy. It can receive vibration signals from the blade tip and root clamps, perform joint spectral analysis and modal identification, and generate two independent control current commands according to a preset collaborative strategy to drive the magnetorheological dampers at the blade tip and root respectively, achieving collaborative suppression of the overall blade vibration. The algorithm possesses online self-learning capabilities and can optimize parameters based on historical control effects.

[0073] This invention provides a dual active and passive vibration damping fixture and a collaborative control method for large turbine blades based on magnetorheological effects. By deeply integrating smart materials, multi-position sensing, and advanced control algorithms, it systematically solves the vibration suppression problem in the precision machining of large flexible blades. This invention creatively arranges active and passive composite vibration damping units at both the blade tip and root, constructing a collaborative control system integrating sensing, decision-making, and actuation. Real-time stepless adjustment of damping is achieved through the controllable rheological properties of magnetorheological fluid. Combined with a fuzzy adaptive collaborative control algorithm, the damping force at both positions can be dynamically adjusted according to the overall vibration state of the blade, realizing intelligent tracking and targeted suppression of multi-mode, full-frequency vibrations. This system not only significantly improves the surface quality, geometric accuracy, and machining efficiency, but also possesses good adaptability to operating conditions, control flexibility, and system robustness. This invention provides an efficient and reliable vibration control solution for the stable precision machining of turbine blades, possessing significant engineering application value and promising prospects for widespread application.

Claims

1. A dual vibration damping fixture for large blades based on magnetorheological effect, characterized in that, include: The blade tip active and passive vibration damping fixture (18), the blade root active and passive vibration damping fixture (16), and the central coordination controller (14) together constitute an active and passive coordinated control system. Both the blade tip active and passive vibration damping fixture and the blade root active and passive vibration damping fixture are equipped with vibration sensors (13) to monitor the vibration status of the corresponding parts in real time. The central coordination controller (14) generates and outputs two independent control commands based on the vibration signals of the blade tip and the blade root, so that the blade tip fixture and the blade root fixture can achieve synchronous and coordinated adaptive vibration damping.

2. The blade tip active and passive vibration damping fixture according to claim 1, characterized in that: The base (1) of the blade tip active and passive vibration damping fixture (18) is rigidly connected to the clamping device (3) by a screw (2), forming a high-rigidity clamping structure, which significantly improves the contact rigidity of the fixture and the blade mating surface. The bottom layer of the base (1) is covered with a lower pad (4), and a damping cavity (5) is placed on the lower pad (4). An upper pad (6) is placed on the damping cavity (5), and a top plate (7) is installed on the upper pad (6). The top plate (7) is connected to the base (1) by a high preload thread, which further enhances the overall structural rigidity. The damping cavity (5) is fixed by two half-cross fixing bodies (12) on the bottom plate. The top plate (7) has two blind holes for positioning. 5) The interior is filled with magnetorheological fluid (8), and four cylindrical magnets (9) are installed in the magnetorheological fluid (8). The cylindrical magnets (9) are wound with coils (10). The damping cavity (5) is provided with 160 ceramic balls (11) with built-in magnetic particles as passive damping elements. The damping cavity (5) is also provided with a mesh structure. The mesh structure is made of high magnetic permeability material and is distributed between the cylindrical magnets (9) and the ceramic balls (11) to guide the uniform distribution of the magnetic field and increase the flow damping of the magnetorheological fluid. The coils (10) are connected to a controllable power supply (15). By adjusting the current, the magnetic field strength is changed, thereby controlling the rheological characteristics of the magnetorheological fluid (8) and realizing the combined active and passive damping function.

3. The blade root active and passive vibration damping fixture according to claim 1, characterized in that: The base (1) of the blade root active and passive vibration damping clamp (16) is rigidly connected to the clamping device (3) by a screw (2) to form a high-rigidity clamping structure, ensuring the stability of the blade root clamping and the rigidity of the mating surface. The bottom layer of the base (1) is covered with a lower pad (4), and two vibration damping cavities (5) are placed side by side on the lower pad (4). The vibration damping cavities (5) are covered with an upper pad (6), and a top plate (7) is installed on the upper pad (6). The top plate (7) and the base (1) are connected by a high preload thread to form a multi-layer composite high-rigidity structure. The vibration damping cavity (5) is fixed by two half-cross fixing bodies (12) on the bottom plate. The top plate (7) has two blind holes for positioning. (5) The interior is filled with magnetorheological fluid (8), and four cylindrical magnets (9) are installed in the magnetorheological fluid (8). The cylindrical magnets (9) are wound with coils (10). The damping cavity (5) is provided with 160 ceramic balls (11) with built-in magnetic particles as passive damping elements. The damping cavity (5) is also provided with a mesh structure. The mesh structure is made of high magnetic permeability material and is distributed between the cylindrical magnets (9) and the ceramic balls (11) to guide the magnetic field to be evenly distributed and increase the flow damping of the magnetorheological fluid. The coils (10) are connected to a controllable power supply (15). By adjusting the current, the magnetic field strength is changed, thereby controlling the rheological characteristics of the magnetorheological fluid (8) and realizing the damping function of active and passive combined.

4. The large-blade active and passive dual vibration damping fixture according to claim 1, characterized in that: The vibration sensor (13) is a multi-sensor fusion unit, which includes a combination of an acceleration sensor, a displacement sensor and a force sensor, and is used to comprehensively monitor the vibration state of the blade from multiple physical dimensions. The vibration sensor (13) is connected to the central coordinating controller (14) and the controllable power supply (15). The central coordinating controller (14) has a built-in fuzzy adaptive control algorithm, which can fuse multi-source sensor information and generate and output two independent control currents based on the vibration signals at the blade tip and blade root positions.

5. The large-blade active and passive dual vibration damping fixture according to claim 1, characterized in that: The blade tip active and passive vibration damping fixture (18) and the blade root active and passive vibration damping fixture (16) are made of high-strength rigid materials. The damping cavity (5) adopts a multi-seal structure design, including sealing rings, sealant and anti-leakage overflow structure, to ensure zero leakage of magnetorheological fluid (8) under high frequency vibration and high pressure conditions, and to ensure the reliability and safety of long-term use.

6. A dual vibration damping fixture for large blades based on magnetorheological effect as described in claim 1, characterized in that: It includes the following steps: Step 1: First, lay the lower shim (4) on the base (1) and ensure that the lower shim (4) is precisely positioned between the half cross fixing bodies (11) to form a bottom buffer and stiffness matching layer; then install the damping cavity (5) between each pair of half cross fixing bodies (12) to achieve precise positioning and rigid fixation of the damping cavity (5) through the half cross fixing bodies (12); then lay the upper shim (6) on the damping cavity (5) to form an upper buffer and stiffness matching layer; finally, install the top plate (7) on the base (1) through a high preload thread structure and achieve precise alignment through the blind hole on the top plate (7) to complete the sealing and pre-tightening of the damping cavity (5); the screw (2) installed on the base is combined with the clamping device (3) to form an adjustable high stiffness clamping interface; Step 2: A mesh structure is pre-installed inside the damping cavity (5). The mesh structure is made of a high magnetic permeability material and is distributed in the internal space of the damping cavity. Then, four cylindrical magnets (9) with coils (10) wound around them are installed through the entire damping cavity (5) to ensure that the cylindrical magnets (9) and the mesh structure are arranged in a spatially staggered manner. Then, magnetorheological fluid (8) is injected into the damping cavity (5), and 160 ceramic balls (11) with built-in magnetic particles are distributed to form a solid-liquid-magnetic-mesh composite damping system. Step 3: Monitor the vibration signal of the large blade in real time under clamping conditions using a vibration sensor (13); Step 4: The central coordinating controller (14) receives the vibration signal and calculates its vibration amplitude and spectral characteristics; Step 5: The central coordinating controller (14) compares the calculated vibration characteristic quantity with the preset threshold and generates control commands according to the preset fuzzy adaptive coordinating control algorithm; Step 6: The control command drives the controllable power supply (15) to output the corresponding current to the coil (10). Step 7: The coil (10) generates a magnetic field of corresponding strength, causing the apparent viscosity and shear yield stress of the magnetorheological fluid (8) in the damping cavity (5) to change instantaneously. At the same time, the magnetic field interacts with the ceramic ball (11) with built-in magnetic particles and the mesh structure through multiple coupling effects. The damping effect is enhanced through multiple mechanisms such as fluid resistance enhancement, magnetic circuit guidance and magneto-solid coupling, thereby adjusting the overall damping force of the fixture and suppressing the vibration of the large blade.

7. The method for coordinated control of active and passive dual vibration damping fixtures for large blades based on magnetorheological effect according to claims 1-6, characterized in that: Includes the following steps: S1. Vibration signals at the blade tip and blade root positions are simultaneously collected using vibration sensors on the blade tip active and passive vibration damping fixtures and the blade root active and passive vibration damping fixtures, respectively. S2. The central coordinating controller performs joint spectrum analysis and feature extraction on the dual-channel vibration signals to obtain a vibration feature set including the main vibration frequency and amplitude of the blade tip, the main vibration frequency and amplitude of the blade root, and the phase difference between the two signals; S3. The central collaborative controller makes a decision based on the vibration feature set and a preset fuzzy adaptive collaborative control algorithm. The decision-making process includes: dynamically selecting a collaborative control strategy based on the ratio of vibration energy between the blade tip and the blade root and the relationship of the dominant frequency, and calculating the first control current I1 and the second control current I2 required to drive the electromagnetic coils of the blade tip clamp and the blade root clamp, respectively. S4. The central coordinating controller synchronously outputs the first control current I1 to the electromagnetic coil of the blade tip clamp and outputs the second control current I2 to the electromagnetic coil of the blade root clamp. S5. Under the influence of their respective magnetic fields, the rheological state of the internal magnetorheological fluid of the blade tip clamp and blade root clamp changes independently, thereby generating independently adjustable and mutually synergistic damping forces at the blade tip and root, which together suppress processing vibration.

8. The cooperative control method according to claim 7, characterized in that, The dynamic selection of the cooperative control strategy in step S3 includes: when the main vibration frequencies of the blade tip and blade root are similar and lower than the first threshold, a same-frequency targeting cooperative strategy is adopted, with the main frequency of the one with greater vibration energy as the common target frequency, and the phase of the dual-path control current is compensated according to the phase difference; when the difference between the main vibration frequencies of the blade tip and blade root is greater than the second threshold, a different-frequency independent targeting strategy is adopted, with the blade tip and blade root controllers using their respective main vibration frequencies as the target frequencies for independent fuzzy control; when the vibration energy at one point of the blade tip or blade root is significantly greater than that at another point, a master-slave enhancement strategy is adopted, with the high-energy position as the master control point for active suppression, and the other position as the slave control point to provide coupling auxiliary damping.

9. The cooperative control method according to claim 7, characterized in that, The fuzzy adaptive cooperative control algorithm described in step S3 includes the following steps: a) Fuzzification: The vibration features extracted in step S2, including vibration amplitude error, error change rate and frequency matching degree, are mapped into fuzzy linguistic variables; b) Fuzzy reasoning: Based on a preset fuzzy rule base, reason about the fuzzified input variables to obtain the fuzzy set of output variables—control current increments; c) Defuzzification: Convert the fuzzy set of the output variables into precise control current increment values; d) Adaptive parameter update: Based on the vibration suppression effect within a control cycle, adjust the weights of some rules in the fuzzy rule base or the fuzzification and defuzzification parameters online to optimize the subsequent control effect.

10. The cooperative control method according to claim 7, characterized in that, In step S3, the central coordinating controller also performs dynamic weight allocation based on the tool space attitude: the system calculates the energy ratio R between the blade tip and blade root vibration signals in real time. E The method infers the approximate machining area of ​​the tool on the blade and dynamically allocates the control weights and strategies of the two vibration damping fixtures accordingly: when the tool is in the blade tip region, the active control of the blade tip fixture is dominant, with the blade root fixture providing assistance; when the tool moves to the middle of the blade, the two fixtures work in a balanced and coordinated manner to jointly suppress coupled vibrations; when the tool approaches the blade root, the high-precision control of the blade root fixture takes precedence. The control strategies between each region are seamlessly switched using a smooth transition algorithm, ensuring the continuity and stability of vibration suppression throughout the entire tool travel. This method enables the vibration damping system to adapt to dynamic changes in the machining position, always maintaining optimal vibration suppression performance.

11. The cooperative control method according to claim 7, characterized in that, In step S3, the central coordinating controller switches between different active and passive control modes according to the frequency band to which the identified main oscillation frequency belongs: in the low frequency band, the active control mode is adopted and a larger control current is output. In the mid-frequency band, a combination of active and passive modes is adopted, with an active tuning current superimposed on the basic passive damping current; In the high-frequency band, a passive control-based mode is adopted to output a stable basic damping current.

12. The method for coordinated control of active and passive dual vibration damping fixtures for large blades based on magnetorheological effect according to claim 7, characterized in that: The described collaborative control algorithm is a fuzzy adaptive control-based algorithm that runs in a central collaborative controller. Based on the real-time spectral changes of the vibration signals from both the blade tip and root, it can select a global vibration suppression mode or a specific frequency-targeted suppression mode according to the processing conditions, and optimize the distribution of damping forces at both positions through a collaborative strategy. It can receive vibration signals from the blade tip and root clamps, perform joint spectral analysis and modal identification, and generate two independent control current commands according to a preset collaborative strategy to drive the magnetorheological dampers at the blade tip and root respectively, achieving collaborative suppression of the overall blade vibration. The algorithm has online self-learning capabilities and can optimize parameters based on historical control effects.

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