Piezoelectric ceramic actuator-based active control device and control method for supporting rigidity of turning type squirrel cage

Abstract

The invention discloses a turning type squirrel cage supporting rigidity active control device and method based on a piezoelectric ceramic actuator, belongs to the technical field of aero-engine rotor dynamics and vibration control, and aims to overcome the defects that an existing squirrel cage supporting rigidity adjusting technology depends on external energy supply, and is low in integration level and slow in response. The device comprises an energy collection module, an actuation decision module and a rigidity execution module, and the energy collection end of the energy collection module is located between a folding type squirrel cage support and a bearing and attached to the outer circle face of the bearing. The signal output end of the energy collection module is connected with the signal input end of an actuation decision module arranged on the folding type squirrel cage support in a sleeving mode, and the energy output end of the actuation decision module is connected with a rigidity execution module and drives the rigidity execution module to extrude cage bar parts of the folding type squirrel cage support. The active control device is mainly used for adjusting the supporting rigidity of a rotor system in the field of aero-engines.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine rotor dynamics and vibration control technology, specifically relating to an active control device and method for the stiffness of a folding squirrel cage support based on a piezoelectric ceramic actuator. Background Technology

[0002] The squirrel cage elastic support is a key component in the rotor system of an aero-engine. It provides elastic support to the rotor through circumferentially distributed flexible cage bars, which can effectively reduce the transmission of rotor vibration to the engine casing and achieve reasonable adjustment of the critical speed of the rotor system. It is an important structure to ensure the stable operation of aero-engines.

[0003] Traditional squirrel-cage elastic supports have a fixed stiffness after manufacturing. However, the rotor system of an aero-engine exhibits significant differences in speed and vibration characteristics under various operating conditions, such as start-up, acceleration, cruise, maneuvering, and deceleration, leading to varying dynamic requirements for support stiffness. Fixed-stiffness squirrel-cage supports cannot meet the optimal dynamic characteristics required for the engine across all operating conditions, potentially causing excessive vibration amplitude and instability during critical speed crossings under specific conditions, thus limiting the engine's operating range and reliability. Therefore, achieving active and controllable adjustment of support stiffness has become an important research direction to broaden the rotor's stable operating range and suppress specific vibrations.

[0004] To address the aforementioned issues, various stiffness adjustment schemes for squirrel-cage supports have been proposed in existing technologies. These schemes often employ external actuation mechanisms such as electromagnetic actuators and hydraulic actuators, adjusting stiffness by applying additional constraints to the support structure or altering its boundary conditions. However, these technical solutions still suffer from several inherent drawbacks: First, they rely on external power sources from the aero-engine for actuation energy, requiring complex power supply and control systems. This not only increases the overall weight and structural complexity of the engine but also raises the risk of system failure. Second, the aero-engine core compartment operates in a harsh environment characterized by high temperatures, strong vibrations, and limited space, making the external actuation mechanisms and control systems poorly adaptable to the environment, and compromising response speed and operational reliability. Third, the substantial amount of vibrational mechanical energy generated during rotor operation is not effectively recovered and utilized; instead, additional energy is required for active stiffness control, resulting in low energy efficiency.

[0005] Therefore, developing an intelligent variable stiffness squirrel cage elastic support technology that can achieve self-powered operation, high integration, rapid response, and adaptability to the harsh environment of aero engines has become an urgent need in the field of aero engine rotor dynamics. Summary of the Invention

[0006] In order to overcome the shortcomings of existing squirrel cage support stiffness adjustment technology, such as reliance on external power supply, low integration, and slow response, this invention provides a rotary squirrel cage support stiffness active control device and control method based on piezoelectric ceramic actuator.

[0007] An active control device for the stiffness of a folding squirrel cage support based on a piezoelectric ceramic actuator is disclosed. The active control device includes an energy harvesting module, an actuation decision module, and a stiffness execution module. The energy harvesting end of the energy harvesting module is located between the folding squirrel cage support and the bearing and is attached to the outer circumferential surface of the bearing. The signal output end of the energy harvesting module is connected to the signal input end of the actuation decision module, which is mounted on the folding squirrel cage support. The energy output end of the actuation decision module is connected to the stiffness execution module and drives the stiffness execution module to compress the cage bars of the folding squirrel cage support, thereby adjusting the working stiffness of the folding squirrel cage support.

[0008] Furthermore, the energy harvesting module includes a ring-shaped piezoelectric ceramic sheet and multiple sets of piezoelectric ceramic sheet leads. The ring-shaped piezoelectric ceramic sheet is disposed between the folding squirrel cage support and the bearing and is attached to the outer circular surface of the bearing. The ring-shaped piezoelectric ceramic sheet is connected to the signal input terminal of the actuation decision module through multiple sets of piezoelectric ceramic sheet leads.

[0009] Furthermore, the annular piezoelectric ceramic sheet has a multi-piece spliced ​​structure. The annular piezoelectric ceramic sheet includes multiple piezoelectric ceramic sub-sheets. The multiple piezoelectric ceramic sub-sheets are evenly distributed and attached to the outer circular surface of the bearing along the circumference. Each piezoelectric ceramic sub-sheet is connected to the signal input terminal of the actuation decision module through a set of piezoelectric ceramic sheet leads.

[0010] Furthermore, the actuation decision module includes an actuation integration box, a signal conditioning unit, an energy storage unit, a logic control unit, and multiple piezoelectric ceramic actuators. The actuation integration box is mounted on a folding squirrel cage support. The signal conditioning unit, energy storage unit, logic control unit, and multiple piezoelectric ceramic actuators are all integrated in the actuation integration box. The signal input terminal of the signal conditioning unit is connected to multiple sets of piezoelectric ceramic sheet leads. The energy output terminal of the signal conditioning unit is connected to the energy input terminal of the energy storage unit. The signal output terminal of the signal conditioning unit is connected to the signal input terminal of the logic control unit. The control signal output terminal of the logic control unit is connected to the control signal input terminal of the energy storage unit. The energy output terminal of the energy storage unit is connected to the energy input terminals of multiple piezoelectric ceramic actuators.

[0011] Furthermore, the piezoelectric ceramic actuator includes stacked piezoelectric ceramic plates and connecting threaded posts. The stacked piezoelectric ceramic plates are installed inside the actuation integration box and connected to the energy output terminal of the energy storage unit via wires. The connecting threaded posts are located at the ends of the stacked piezoelectric ceramic plates, with one end of the connecting threaded posts fixedly connected to the stacked piezoelectric ceramic plates and the other end of the connecting threaded posts extending to the outside of the actuation integration box and used to connect to the stiffness actuation module.

[0012] Furthermore, the stiffness execution module includes multiple stiffness adjustment components, which are equidistantly arranged circumferentially on the open end of the actuation integration box. Each stiffness adjustment component is installed on a piezoelectric ceramic actuator. The stiffness adjustment component includes a transmission mechanical arm, a constraint clamp, a wedge block, and a metal rubber layer. One end of the transmission mechanical arm is sleeved on the connecting threaded post in the piezoelectric ceramic actuator and is detachably connected to the connecting threaded post. The wedge block is set on the other end of the transmission mechanical arm and is fixedly connected to the transmission mechanical arm through the constraint clamp. Both the wedge block and the metal rubber layer are set in a folding cage bar on the folding squirrel cage support, and the other end of the wedge block is in close contact with the metal rubber layer. The wedge block moves axially with the micro-displacement of the transmission mechanical arm, and its top end axially compresses the metal rubber layer. At the same time, the inclined surfaces on both sides convert the axial movement into radial compression constraint on the squirrel cage bar, thereby realizing the active adjustment of the equivalent stiffness and damping of the folding squirrel cage support.

[0013] Furthermore, the piezoelectric ceramic actuator also includes a preload structure for adjusting the preload of the stacked piezoelectric ceramic sheets. The preload structure includes a helical spring and a locking nut. The helical spring is disposed between the stacked piezoelectric ceramic sheets and the transmission mechanical arm and is sleeved on the connecting threaded post. The locking nut is disposed on the outside of the transmission mechanical arm and is sleeved on the connecting threaded post. The locking nut is threadedly connected to the connecting threaded post. The compression of the helical spring is adjusted by the locking nut, thereby adjusting the preload acting on the stacked piezoelectric ceramic sheets.

[0014] An active control method for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator, the method being implemented through the following steps:

[0015] Step 1: The rotor vibration energy is collected in real time through the energy harvesting module and converted into an electrical signal. The converted electrical signal is then transmitted to the actuation decision module.

[0016] Step 2: The actuation decision module processes the electrical signal input in Step 1 and determines whether the stiffness adjustment conditions are met; if they are met, it generates and sends a stiffness adjustment command to the stiffness execution module.

[0017] Step 3: The stiffness execution module responds to the adjustment command in step 2 and squeezes and constrains the squirrel cage bars in the folding squirrel cage support, thereby actively adjusting the equivalent support stiffness and damping of the folding squirrel cage support to achieve the enhancement or weakening effect.

[0018] Furthermore, in step 2, the stiffness adjustment condition of the folding squirrel cage support is that the rotor speed reaches or exceeds a preset critical speed threshold, or the vibration amplitude exceeds a preset safety threshold.

[0019] Furthermore, in step 3, the compression constraint is achieved by the end of the stiffness execution module advancing axially to compress the cage bars of the folding squirrel cage support, thereby enhancing the constraint and increasing the stiffness; or by the end of the stiffness execution module retracting axially to release or reduce the constraint and decrease the stiffness.

[0020] The beneficial effects of this application compared to the prior art are:

[0021] 1. The present application provides a rotary squirrel cage support stiffness active control device based on piezoelectric ceramic actuator. On the basis of the existing disclosed squirrel cage support stiffness adjustment technology, it uses annular piezoelectric ceramic sheet to collect the vibration mechanical energy of the rotor itself and convert it into electrical energy to provide energy for active stiffness control. It gets rid of the dependence on external power supply and complex power supply cables, greatly reduces the risk of system failure, and can adapt to the harsh working environment of high temperature, strong vibration and confined space in the core compartment of aero-engine.

[0022] 2. The present application provides a piezoelectric ceramic actuator-based active control device for the stiffness of a folding squirrel cage support. The piezoelectric ceramic actuator is used as the drive component. It has millisecond-level or even faster response capability and displacement control accuracy down to the nanometer level. It can realize rapid and fine adjustment of support stiffness and can quickly adapt to the rotor dynamics requirements of aero-engines under different operating conditions.

[0023] 3. The active control device for stiffness of a folding squirrel cage support based on a piezoelectric ceramic actuator provided in this application tightly integrates an energy harvesting module, an actuation decision module, and a stiffness execution module on the main body of the folding squirrel cage support. The layout of each functional module is compact, without occupying additional internal space of the aero-engine, effectively controlling the overall weight and volume of the device, and meeting the design requirements of lightweight and miniaturized aero-engines.

[0024] 4. The present application provides a piezoelectric ceramic actuator-based rotary squirrel cage support stiffness active control device, which introduces a metal rubber layer into the stiffness execution module. During the wedge block compression process, the metal rubber layer not only plays the role of elastic buffering and uniform force transmission, but also provides adjustable damping characteristics. This realizes the synchronous coupling adjustment of support stiffness and damping. Compared with single stiffness adjustment, it can more effectively suppress rotor vibration and improve the operating stability of the rotor system.

[0025] 5. The present application provides a piezoelectric ceramic actuator-based rotary squirrel cage support stiffness active control device, which realizes stiffness enhancement / reduction through the axial advancement / retraction of wedge blocks. The adjustment process is reversible and controllable, and can adjust the support stiffness in real time according to the dynamic requirements of different working conditions such as aero-engine start-up, acceleration, cruise, and maneuvering, thus broadening the stable working range of the rotor system.

[0026] 6. The present application provides a method for active control of the stiffness of a folding squirrel cage support based on a piezoelectric ceramic actuator. It relies on the positive and inverse piezoelectric effects of piezoelectric ceramics to realize vibration energy recovery and in-situ active stiffness regulation. It can achieve self-powered active control, get rid of dependence on external energy, and has the characteristics of fast response speed, high control accuracy, and strong dynamic adaptability. It is suitable for the harsh environment of all working conditions of aero-engines and significantly improves the stability and energy utilization efficiency of the rotor system. Attached Figure Description

[0027] Figure 1 This is a front view of the active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator as described in this application.

[0028] Figure 2 This is a three-axis view of the active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator as described in this application.

[0029] Figure 3 This is a top view of the active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator as described in this application;

[0030] Figure 4 This is a cross-sectional view of a piezoelectric ceramic actuator-based folding squirrel cage support stiffness active control device as described in this application;

[0031] Figure 5 This is a schematic diagram showing the connection between the piezoelectric ceramic actuator and the stiffness adjustment component in the piezoelectric ceramic actuator-based active control device for the stiffness of a folding squirrel cage support described in this application.

[0032] Figure 6 This is a schematic diagram of the internal unit flow of the actuation integration box in the active control device for the stiffness of the folding squirrel cage support based on a piezoelectric ceramic actuator described in this application.

[0033] In the diagram: 1. Folding squirrel cage support; 2. Actuation integration box; 3. Bearing; 4. Ring-shaped piezoelectric ceramic sheet; 5. Piezoelectric ceramic sheet lead wire; 6. Signal conditioning unit; 7. Energy storage unit; 8. Logic control unit; 9. Stacked piezoelectric ceramic sheets; 10. Helical spring; 11. Locking nut; 12. Transmission robotic arm; 13. Constraint fixture; 14. Wedge block; 15. Metal rubber layer; 16. Piezoelectric ceramic actuator. Detailed Implementation

[0034] Specific implementation method one: Combining Figure 1 and Figure 6This embodiment describes an active control device for the stiffness of a folding squirrel cage support based on a piezoelectric ceramic actuator. It includes an energy harvesting module, an actuation decision module, and a stiffness execution module. The energy harvesting end of the energy harvesting module is located between the folding squirrel cage support 1 and the bearing 3 and is attached to the outer circumference of the bearing 3. The signal output end of the energy harvesting module is connected to the signal input end of the actuation decision module mounted on the folding squirrel cage support 1. The energy output end of the actuation decision module is connected to the stiffness execution module and drives the stiffness execution module to compress the cage bars of the folding squirrel cage support 1, thereby adjusting the working stiffness of the folding squirrel cage support 1.

[0035] The core of the active control device provided in this embodiment lies in integrating energy harvesting, signal decision-making, and stiffness execution functions into one unit. Utilizing the direct and inverse piezoelectric effects of piezoelectric ceramics, it achieves the recovery and utilization of rotor vibration energy and the in-situ rapid active adjustment of support stiffness. The energy harvesting module includes a ring-shaped piezoelectric ceramic sheet 4 and multiple sets of piezoelectric ceramic sheet leads 5. The ring-shaped piezoelectric ceramic sheet 4 is disposed between the folding squirrel cage support 1 and the bearing 3 and is attached to the outer circumferential surface of the bearing 3. The ring-shaped piezoelectric ceramic sheet 4 is connected to the signal input terminal of the actuation decision module through the multiple sets of piezoelectric ceramic sheet leads 5. When the energy harvesting module is working, the mechanical energy transmitted from rotor vibration to the bearing 3 is converted into an AC electrical signal using the direct piezoelectric effect, and this electrical signal is transmitted to the actuation decision module through the piezoelectric ceramic sheet leads 5.

[0036] The actuation decision module includes an actuation integration box 2, a signal conditioning unit 6, an energy storage unit 7, a logic control unit 8, and multiple piezoelectric ceramic actuators 16. The actuation integration box 2 is mounted on a folding squirrel cage support 1. The signal conditioning unit 6, energy storage unit 7, logic control unit 8, and multiple piezoelectric ceramic actuators 16 are all integrated within the actuation integration box 2. The signal input terminal of the signal conditioning unit 6 is connected to multiple sets of piezoelectric ceramic sheet leads 5. The energy output terminal of the signal conditioning unit 6 is connected to the energy input terminal of the energy storage unit 7. The signal output terminal of the signal conditioning unit 6 is connected to the signal input terminal of the logic control unit 8. The control signal output terminal of the logic control unit 8 is connected to the control signal input terminal of the energy storage unit 7. The energy output terminal of the energy storage unit 7 is connected to the energy input terminals of the multiple piezoelectric ceramic actuators 16. The actuation decision module processes the current signal received through the leads 5 and makes a stiffness enhancement / decrease decision. When the actuation decision module is working, the signal conditioning unit 6 rectifies, filters, and stabilizes the received AC signal sequentially, and then transmits the processed electrical energy to the energy storage unit 7 for storage, providing energy reserves for stiffness adjustment. The logic control unit 8 receives the conditioned electrical signal output by the signal conditioning unit 6, completes threshold judgment and stiffness control decision according to the preset vibration electrical signal threshold strategy, and controls the energy storage unit 7 to release electrical energy to the piezoelectric ceramic actuator 16 according to the decision result. The piezoelectric ceramic actuator 16 includes stacked piezoelectric ceramic sheets 9 and connecting threaded posts. The stacked piezoelectric ceramic sheets 9 are made of multiple layers of piezoelectric ceramic sheets bonded together. The stacked piezoelectric ceramic sheets 9 are installed in the actuation integration box 2 and connected to the energy output terminal of the energy storage unit 7 through wires. The connecting threaded posts are located at the ends of the stacked piezoelectric ceramic sheets 9, with one end of the connecting threaded posts fixedly connected to the stacked piezoelectric ceramic sheets 9 and the other end of the connecting threaded posts extending to the outside of the actuation integration box 2 and used to connect to the stiffness execution module. The piezoelectric ceramic actuator 16, as an integrated drive unit, utilizes the inverse piezoelectric effect to convert electrical energy into mechanical micro-displacement. It serves as the output of the actuation decision module, and the output micro-displacement drives the stiffness execution module to perform actions. The energy storage unit 7 employs a supercapacitor, characterized by fast charging and discharging speeds, long cycle life, and high power density. Specifically, a lithium-ion capacitor can be used, combining the high energy density of lithium batteries with the high power density of supercapacitors. This enables efficient energy storage under low rotor vibration conditions and rapid energy release under high vibration conditions, further improving the device's energy utilization efficiency and response speed. The logic control unit 8 uses a preset vibration electrical signal threshold strategy. This strategy triggers a stiffness adjustment decision when either the rotor speed reaches or exceeds a preset critical speed threshold, or the rotor vibration amplitude exceeds a preset safety threshold.

[0037] The stiffness execution module includes multiple stiffness adjustment components, which are equidistantly arranged circumferentially on the open end of the actuation integration box 2. Each stiffness adjustment component is mounted on a piezoelectric ceramic actuator 16. Each stiffness adjustment component includes a transmission mechanical arm 12, a constraint clamp 13, a wedge block 14, and a metal-rubber layer 15. One end of the transmission mechanical arm 12 is sleeved on and detachably connected to the connecting threaded post in the piezoelectric ceramic actuator 16. The wedge block 14 is located on the other end of the transmission mechanical arm 12 and is fixedly connected to it via the constraint clamp 13. Both the wedge block 14 and the metal-rubber layer 15 are located in a folding cage bar on the folding squirrel cage support 1. The other end of the wedge block 14 is in close contact with the metal rubber layer 15. The transmission mechanical arm 12 is connected to the piezoelectric ceramic actuator 16. It generates precise micro-displacement in response to the drive of the piezoelectric ceramic actuator 16. The constraint clamp 13 is used to clamp the wedge block 14. The wedge block 14 moves axially along the micro-displacement of the transmission mechanical arm 12. Its top end axially compresses the metal rubber layer 15. At the same time, the inclined surfaces on both sides convert the axial movement into radial compression constraint on the cage bars of the squirrel cage, realizing the active adjustment of the equivalent stiffness and damping of the folding and rotating squirrel cage support 1. The metal rubber layer 15 is a porous elastic structure woven from metal wires, which has the functions of elastic buffering and uniform force transmission. At the same time, it can provide adjustable damping, realizing the coupling adjustment of stiffness and damping.

[0038] Specific Implementation Method Two: Combining Figures 1 to 6 This embodiment further defines the first embodiment. The annular piezoelectric ceramic sheet 4 is a multi-piece spliced ​​structure, comprising multiple piezoelectric ceramic sub-sheets. These sub-sheets are evenly distributed circumferentially and attached to the outer surface of the bearing 3. Each sub-sheet is connected to the signal input terminal of the actuation decision module via a set of piezoelectric ceramic sheet leads 5. Other components and connections are the same as in the first embodiment.

[0039] In this embodiment, the annular piezoelectric ceramic sheet 4 adopts a multi-piece splicing structure design, which can more comprehensively collect vibration energy from different directions of the rotor, improve energy collection efficiency, and ensure normal power supply of the device under low rotor vibration conditions.

[0040] Specific implementation method three: Combining Figures 1 to 6This embodiment further defines the first embodiment. The piezoelectric ceramic actuator 16 also includes a pre-tensioning structure for adjusting the pre-tension force of the stacked piezoelectric ceramic plates 9. The pre-tensioning structure includes a helical spring 10 and a locking nut 11. The helical spring 10 is disposed between the stacked piezoelectric ceramic plates 9 and the transmission mechanical arm 12 and is sleeved on the connecting threaded post. The locking nut 11 is disposed on the outside of the transmission mechanical arm 12 and is sleeved on the connecting threaded post, and the locking nut 11 is threadedly connected to the connecting threaded post. The compression of the helical spring 10 is adjusted by the locking nut 11, thereby adjusting the pre-tension force acting on the stacked piezoelectric ceramic plates 9. Other components and connection methods are the same as in the second embodiment.

[0041] In this embodiment, the preload of the stacked piezoelectric ceramic sheets 9 is precisely adjusted by the helical spring 10 and the locking nut 11. This structure has the characteristics of compact axial dimensions, high rigidity and stable preload, and is suitable for application scenarios in aero-engines where the structural compactness requirement is high.

[0042] Specific implementation method four: Combination Figures 1 to 6 This embodiment describes an active control method for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator. The method is implemented through the following steps:

[0043] Step 1: The rotor vibration energy is collected in real time through the energy harvesting module and converted into an electrical signal. The converted electrical signal is then transmitted to the actuation decision module.

[0044] Step 2: The actuation decision module processes the electrical signal input in Step 1 and determines whether the stiffness adjustment conditions are met; if they are met, it generates and sends a stiffness adjustment command to the stiffness execution module.

[0045] Step 3: The stiffness execution module responds to the adjustment command in step 2 and compresses and constrains the cage bars in the folding squirrel cage support 1, thereby actively adjusting the equivalent support stiffness and damping of the folding squirrel cage support 1 to achieve the effect of strengthening or weakening.

[0046] Step 1 in this embodiment aims to achieve vibration energy harvesting and electrical signal conversion. The energy harvesting module collects the mechanical energy transmitted by rotor vibration in real time through an annular piezoelectric ceramic sheet 4 attached to the bearing 3, converts it into an AC signal using the positive piezoelectric effect, and transmits the signal to the actuation integration box 2 of the actuation decision module through the piezoelectric ceramic sheet lead wire 5. Step 2 aims to achieve electrical signal processing and stiffness decision generation. The signal conditioning unit 6 in the actuation integration box 2 performs rectification, filtering, and voltage stabilization processing on the received AC signal in sequence. The processed electrical energy is sent to the energy storage unit 7 for storage, and the conditioned electrical signal is synchronously transmitted to the logic control unit 8. The logic control unit 8 determines whether the stiffness adjustment conditions are met according to the preset vibration electrical signal threshold strategy. If the conditions are met, a stiffness enhancement / decrease command is generated. The energy storage unit 7 is controlled to release corresponding electrical energy to the piezoelectric ceramic actuator 16. Step 3 aims to achieve stiffness execution and active adjustment. The piezoelectric ceramic actuator 16 converts the received electrical energy into mechanical micro-displacement, driving the transmission mechanical arm 12 to move the wedge block 14 held by the top constraint clamp 13 along the axial direction within the cage bars of the folding squirrel cage support 1. If the stiffness enhancement command is given, the wedge block 14 advances along the axial direction, its top end compresses the metal rubber layer 15, and at the same time, the two inclined surfaces radially compress the cage bars, enhancing the constraint on the cage bars and improving the equivalent stiffness and damping of the folding squirrel cage support 1. If the stiffness reduction command is given, the wedge block 14 retracts along the axial direction, releasing / reducing the compression constraint on the metal rubber layer 15 and the cage bars, reducing the equivalent stiffness and damping of the folding squirrel cage support 1, and completing the active adjustment of the support stiffness.

[0047] The control method provided in this embodiment includes continuously collecting vibration energy and converting it into an electrical signal; processing and judging the signal, and generating a control command when the stiffness adjustment condition (such as exceeding the critical speed) is met; executing the command to drive the wedge block to radially compress or release the cage bars, thereby quickly and reversibly switching the equivalent stiffness state of the support structure. It integrates energy collection, signal decision-making and stiffness execution functions into one, and utilizes the positive and inverse piezoelectric effects of piezoelectric ceramics to realize the recovery and utilization of rotor vibration energy and the in-situ rapid and active adjustment of support stiffness.

[0048] In this embodiment, the stiffness adjustment condition of the folding squirrel cage support 1 mentioned in step 2 is that the rotor speed reaches or exceeds the preset critical speed threshold, or the vibration amplitude exceeds the preset safety threshold. The compression constraint mentioned in step 3 is that the end of the stiffness execution module is pushed forward along the axis to compress the squirrel cage bars of the folding squirrel cage support 1 to enhance the constraint and increase the stiffness; or the end of the stiffness execution module is pulled back along the axis to release or reduce the constraint and reduce the stiffness.

[0049] The present invention has been disclosed above with preferred embodiments, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed structure and technical content to create equivalent embodiments without departing from the scope of the present invention. However, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A device for actively controlling the stiffness of a folding squirrel cage support based on a piezoelectric ceramic actuator, characterized in that: The active control device includes an energy harvesting module, an actuation decision module, and a stiffness execution module. The energy harvesting end of the energy harvesting module is located between the folding squirrel cage support (1) and the bearing (3) and is attached to the outer circular surface of the bearing (3). The signal output end of the energy harvesting module is connected to the signal input end of the actuation decision module mounted on the folding squirrel cage support (1). The energy output end of the actuation decision module is connected to the stiffness execution module and drives the stiffness execution module to squeeze the cage bars of the folding squirrel cage support (1), thereby adjusting the working stiffness of the folding squirrel cage support (1).

2. The active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 1, characterized in that: The energy harvesting module includes a ring-shaped piezoelectric ceramic sheet (4) and multiple sets of piezoelectric ceramic sheet leads (5). The ring-shaped piezoelectric ceramic sheet (4) is placed between the folding squirrel cage support (1) and the bearing (3) and is attached to the outer circular surface of the bearing (3). The ring-shaped piezoelectric ceramic sheet (4) is connected to the signal input terminal of the actuation decision module through multiple sets of piezoelectric ceramic sheet leads (5).

3. The active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 2, characterized in that: The annular piezoelectric ceramic sheet (4) is a multi-piece spliced ​​structure. The annular piezoelectric ceramic sheet (4) includes multiple piezoelectric ceramic sub-sheets. The multiple piezoelectric ceramic sub-sheets are evenly distributed and attached to the outer circular surface of the bearing (3) along the circumference. Each piezoelectric ceramic sub-sheet is connected to the signal input terminal of the actuation decision module through a set of piezoelectric ceramic sheet leads (5).

4. The active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 2 or 3, characterized in that: The actuation decision module includes an actuation integration box (2), a signal conditioning unit (6), an energy storage unit (7), a logic control unit (8), and multiple piezoelectric ceramic actuators (16). The actuation integration box (2) is mounted on a folding squirrel cage support (1). The signal conditioning unit (6), the energy storage unit (7), the logic control unit (8), and the multiple piezoelectric ceramic actuators (16) are all integrated in the actuation integration box (2). The signal input terminal of the signal conditioning unit (6) is connected to multiple sets of piezoelectric ceramic sheet leads (5). The energy output terminal of the signal conditioning unit (6) is connected to the energy input terminal of the energy storage unit (7). The signal output terminal of the signal conditioning unit (6) is connected to the signal input terminal of the logic control unit (8). The control signal output terminal of the logic control unit (8) is connected to the control signal input terminal of the energy storage unit (7). The energy output terminal of the energy storage unit (7) is connected to the energy input terminal of the multiple piezoelectric ceramic actuators (16).

5. The active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 4, characterized in that: The piezoelectric ceramic actuator (16) includes stacked piezoelectric ceramic plates (9) and connecting threaded post. The stacked piezoelectric ceramic plates (9) are installed in the actuation integration box (2) and connected to the energy output end of the energy storage unit (7) via wires. The connecting threaded post is located at the end of the stacked piezoelectric ceramic plates (9), and one end of the connecting threaded post is fixedly connected to the stacked piezoelectric ceramic plates (9). The other end of the connecting threaded post extends to the outside of the actuation integration box (2) and is used to connect to the stiffness actuation module.

6. The active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 5, characterized in that: The stiffness execution module includes multiple stiffness adjustment components, which are equidistantly arranged circumferentially on the open end of the actuation integration box (2). Each stiffness adjustment component is mounted on a piezoelectric ceramic actuator (16). The stiffness adjustment component includes a transmission mechanical arm (12), a constraint clamp (13), a wedge block (14), and a metal rubber layer (15). One end of the transmission mechanical arm (12) is fitted onto the connecting threaded post in the piezoelectric ceramic actuator (16) and is detachably connected to the connecting threaded post. The wedge block (14) is set on the other end of the transmission mechanical arm (12). The wedge block (14) and the metal rubber layer (15) are fixedly connected to the transmission mechanical arm (12) through the constraint clamp (13). The wedge block (14) and the metal rubber layer (15) are both set in a folding cage bar on the folding squirrel cage support (1). The other end of the wedge block (14) is in close contact with the metal rubber layer (15). The wedge block (14) moves axially with the micro displacement of the transmission mechanical arm (12). Its top end axially squeezes the metal rubber layer (15). At the same time, the inclined surfaces on both sides convert the axial movement into radial compression constraint on the squirrel cage bar, thereby realizing the active adjustment of the equivalent stiffness and damping of the folding squirrel cage support (1).

7. The active control device for the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 6, characterized in that: The piezoelectric ceramic actuator (16) also includes a pre-tightening structure for adjusting the pre-tightening force of the stacked piezoelectric ceramic plates (9). The pre-tightening structure includes a helical spring (10) and a locking nut (11). The helical spring (10) is disposed between the stacked piezoelectric ceramic plates (9) and the transmission mechanical arm (12) and is sleeved on the connecting threaded post. The locking nut (11) is disposed on the outside of the transmission mechanical arm (12) and is sleeved on the connecting threaded post. The locking nut (11) is threadedly connected to the connecting threaded post. The compression of the helical spring (10) is adjusted by the locking nut (11), thereby adjusting the pre-tightening force acting on the stacked piezoelectric ceramic plates (9).

8. A control method using the piezoelectric ceramic actuator-based active control device for the support stiffness of a rotating squirrel cage as described in any one of claims 1 to 7, characterized in that: The method is implemented through the following steps: Step 1: The rotor vibration energy is collected in real time through the energy harvesting module and converted into an electrical signal. The converted electrical signal is then transmitted to the actuation decision module. Step 2: The actuation decision module processes the electrical signal input in Step 1 and determines whether the stiffness adjustment conditions are met; if they are met, it generates and sends a stiffness adjustment command to the stiffness execution module. Step 3: The stiffness execution module responds to the adjustment command in step 2 and squeezes and constrains the cage bars in the folding squirrel cage support (1), thereby actively adjusting the equivalent support stiffness and damping of the folding squirrel cage support (1) to achieve the enhancement or weakening effect.

9. The method for active control of the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 8, characterized in that: In step 2, the stiffness adjustment condition of the folding squirrel cage support (1) is that the rotor speed reaches or exceeds the preset critical speed threshold, or the vibration amplitude exceeds the preset safety threshold.

10. The method for active control of the support stiffness of a folding squirrel cage based on a piezoelectric ceramic actuator according to claim 8, characterized in that: In step 3, the compression constraint is achieved by pushing the end of the stiffness execution module axially to compress the cage bars of the folding squirrel cage support (1) to enhance the constraint and increase the stiffness; or by retracting the end of the stiffness execution module axially to release or reduce the constraint and decrease the stiffness.

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