High-rigidity cantilever beam oscillation starting device

Abstract

The invention relates to the technical field of micro-nano-scale dynamic testing, and discloses a high-rigidity cantilever beam oscillation starting device, which comprises a cantilever beam placing frame, an oscillation starting device and a vibration starting device, the displacement module is provided with an experiment probe used for being in contact with the high-rigidity cantilever beam; the downward pressing control module is connected with the displacement module and used for controlling the experiment probe to execute downward pressing loading action so as to enable the high-rigidity cantilever beam to deform and then execute rapid separation action; and the data acquisition module is used for acquiring a free vibration signal generated by the high-rigidity cantilever beam after the experimental probe is separated from the high-rigidity cantilever beam. A set of experimental device combining a displacement table, piezoelectric ceramics and an experimental probe is designed. The displacement table has multi-degree-of-freedom and high-resolution displacement output capacity, the experimental probe can be quickly moved to a target area, piezoelectric ceramics are high in response frequency and high in stretching speed, and remarkable deformation can be generated in a short time.

Description

Technical Field

[0001] This invention relates to the field of micro-nano scale dynamic testing technology, specifically a high-stiffness cantilever beam vibration initiation device. Background Technology

[0002] In modern scientific research, it is challenging to induce vibration in a high-stiffness cantilever beam and allow it to vibrate freely without interference, thereby determining its natural frequency. In the field of micro / nano-scale dynamics testing, there are three intractable contradictions regarding the testing of free vibration and natural frequencies of high-stiffness cantilever beams.

[0003] First, there is the contradiction of energy demand. According to the bending vibration equation of beams, the natural frequency of high-stiffness cantilever beams often exceeds 50kHz. In order to excite effective vibration, a large amount of energy must be injected in a very short time. However, the microscale space imposes strict limitations on the size of the actuator. Traditional electromagnetic exciters in this context reveal problems such as low power density and low energy conversion efficiency, making it difficult to meet the energy demand for exciting vibration of high-stiffness cantilever beams. Second, the problem of boundary condition interference cannot be ignored. At the moment of vibration initiation, the probe contact force will inevitably introduce initial stress. Experimental data clearly show that even a slight deviation in contact force will cause a large shift in the measured frequency of the cantilever beam, which in turn leads to a large error in the calculation of the equivalent mass, seriously affecting the accuracy of the test results. Third, there is the bottleneck problem of signal fidelity. The transient vibration response time of a high-stiffness cantilever beam is extremely short. However, the traditional Wheatstone bridge with data acquisition card has limitations in bandwidth and sampling rate, which makes it impossible to accurately capture the complete vibration characteristic signal. This can easily lead to signal distortion, making the acquired data unable to truly reflect the actual vibration of the cantilever beam and hindering the accurate measurement of the natural frequency.

[0004] Therefore, this invention proposes a high-stiffness cantilever beam vibration initiation device. This device enables the high-stiffness cantilever beam to achieve free vibration under conditions unaffected by boundary conditions, thereby allowing for accurate testing of its natural frequency. It solves the difficulties of insufficient energy injection at microscale and the impact of the vibration initiation device on the free vibration of the high-stiffness cantilever beam after initiation.

[0005] Therefore, the purpose of this invention is to provide a high-rigidity cantilever beam vibration initiation device to overcome the shortcomings of the prior art. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a high-rigidity cantilever beam vibration initiation device, which solves the problem that insufficient energy cannot be injected at a small scale, and that the vibration initiation device affects the free vibration of the high-rigidity cantilever beam after vibration initiation.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a high-stiffness cantilever beam vibration initiation device, comprising:

[0008] Cantilever beam support frame for supporting high-rigidity cantilever beams;

[0009] The displacement module is equipped with an experimental probe for contacting the high-rigidity cantilever beam.

[0010] The pressure control module, connected to the displacement module, is used to control the experimental probe to perform a pressure loading action to deform the high-stiffness cantilever beam and then perform a rapid separation action.

[0011] The data acquisition module is used to acquire the free vibration signal generated by the high-stiffness cantilever beam after the experimental probe separates from the high-stiffness cantilever beam.

[0012] Preferably, the displacement module includes a piezoelectric ceramic, and the pressure control module controls the voltage applied to the piezoelectric ceramic to drive the experimental probe to perform pressure loading and rapid separation actions.

[0013] Preferably, the displacement module further includes a displacement stage and a crossbeam fixed to the displacement stage. The piezoelectric ceramic and the experimental probe are connected to the displacement stage through the crossbeam. The displacement stage is used to adjust the macroscopic spatial position of the experimental probe.

[0014] Preferably, the displacement module further includes a multi-degree-of-freedom displacement stage for macroscopically adjusting the position of the experimental probe and a nanometer stage for microscopically adjusting the position.

[0015] Preferably, the device further includes a high-precision industrial camera for observing and aligning the relative positions of the experimental probe and the high-rigidity cantilever beam before they come into contact.

[0016] Preferably, the device further includes a precision balance for measuring and controlling the initial contact force between the experimental probe and the high-stiffness cantilever beam when they come into contact.

[0017] Preferably, the data acquisition module includes:

[0018] A Wheatstone bridge integrated on the high-rigidity cantilever beam for converting vibration strain into a voltage signal;

[0019] The amplifier connected to the Wheatstone bridge;

[0020] A high-speed data acquisition card connected to the amplifier.

[0021] Preferably, the high-speed data acquisition card has a data sampling rate of not less than 1 MS / s and a data resolution of not less than 24 bits.

[0022] Preferably, the device further includes a host computer connected to the data acquisition module, the host computer being used to process the acquired free vibration signals and to determine the natural frequency of the high-stiffness cantilever beam.

[0023] Preferably, the tip of the experimental probe is provided with a ball head made of a high-hardness, wear-resistant material.

[0024] This invention provides a high-rigidity cantilever beam vibration initiation device. It has the following beneficial effects:

[0025] 1. This invention presents an experimental apparatus combining a displacement stage, piezoelectric ceramics, and an experimental probe. The displacement stage possesses multi-degree-of-freedom, high-resolution displacement output capabilities, enabling rapid movement of the experimental probe to the target area. The piezoelectric ceramics exhibit high response frequency and fast expansion / contraction speed, allowing for significant deformation within a short time. The experimental probe is made of high-hardness, high-wear-resistant materials, with a smooth surface and precise geometry. By coarsely adjusting the probe position with the displacement stage and finely adjusting with the piezoelectric ceramics, coupled with real-time monitoring by sensors, precise displacement alignment of the probe with the cantilever beam is achieved, while controlling the initial contact force to a minimal range to avoid adverse effects on the mechanical properties of the cantilever beam.

[0026] 2. In this invention, during vibration excitation, the piezoelectric ceramic rapidly expands and contracts under electrical signal control. Force is applied to the cantilever beam via a probe, causing it to deform. Subsequently, the beam rapidly shortens, releasing the constraint force, allowing the cantilever beam to achieve interference-free free vibration. This device effectively solves the problem of precise displacement alignment without affecting free vibration, significantly improving measurement accuracy and precision, and enabling the measurement of natural frequencies up to 160kHz. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the device flow of the present invention;

[0028] Figure 2 This is a schematic diagram of the experimental apparatus design for the present invention;

[0029] Figure 3 This is a flowchart of the cantilever beam vibration experiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the overall experimental process of the present invention.

[0031] The components include: 1. Displacement stage; 2. High-precision industrial camera; 3. Precision balance; 4. Cantilever beam placement frame; 5. Crossbeam; 6. Piezoelectric ceramic; and 7. Experimental probe. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see the appendix Figure 1 - Appendix Figure 4 This invention provides a high-stiffness cantilever beam vibration initiation device, comprising:

[0034] Cantilever beam support frame 4 for supporting high-rigidity cantilever beams;

[0035] The displacement module is equipped with an experimental probe 7 for contacting a high-stiffness cantilever beam.

[0036] The pressure control module, connected to the displacement module, is used to control the experimental probe 7 to perform a pressure loading action to deform the high-stiffness cantilever beam and then perform a rapid separation action.

[0037] The data acquisition module is used to acquire the free vibration signal generated by the high-stiffness cantilever beam after the experimental probe 7 separates from the high-stiffness cantilever beam.

[0038] The displacement module includes a piezoelectric ceramic 6. The pressure control module controls the voltage applied to the piezoelectric ceramic 6 to drive the experimental probe 7 to perform pressure loading and rapid separation actions.

[0039] The displacement module also includes a displacement stage 1 and a crossbeam 5 fixed on the displacement stage 1. The piezoelectric ceramic 6 and the experimental probe 7 are connected to the displacement stage 1 through the crossbeam 5. The displacement stage 1 is used to adjust the macroscopic spatial position of the experimental probe 7.

[0040] The displacement module also includes a multi-degree-of-freedom displacement stage 1 for macroscopically adjusting the position of the experimental probe 7 and a nanometer stage for microscopically adjusting the position.

[0041] The device also includes a high-precision industrial camera 2, used to observe and align the relative positions of the experimental probe 7 and the high-rigidity cantilever beam before they come into contact.

[0042] The device also includes a precision balance 3, used to measure and control the initial contact force between the experimental probe 7 and the high-stiffness cantilever beam when they come into contact.

[0043] The data acquisition module includes:

[0044] A Wheatstone bridge integrated on a high-rigidity cantilever beam to convert vibration strain into a voltage signal;

[0045] Amplifier connected to a Wheatstone bridge;

[0046] A high-speed data acquisition card connected to the amplifier.

[0047] The high-speed data acquisition card has a data sampling rate of no less than 1 MS / s and a data resolution of no less than 24 bits.

[0048] The device also includes a host computer connected to the data acquisition module. The host computer is used to process the acquired free vibration signals and to determine the natural frequency of the high-stiffness cantilever beam.

[0049] The tip of the experimental probe 7 is equipped with a ball head made of a high-hardness, wear-resistant material.

[0050] The specific embodiments of the present invention are as follows:

[0051] A high-stiffness cantilever beam vibration initiation device is used to enable high-stiffness cantilever beams to achieve free vibration. The specific process is as follows: Figure 1 As shown.

[0052] The first step was the design of the experimental platform. This platform cleverly combines a displacement stage 1, piezoelectric ceramic 6, and experimental probe 7 to construct a high-precision displacement control system. The displacement stage 1 possesses multi-degree-of-freedom motion capabilities, encompassing three translational degrees of freedom (X, Y, Z) and three rotational degrees of freedom. It boasts high linear and angular displacement accuracy, enabling rapid movement of the experimental probe 7 to a position adjacent to the target area. The piezoelectric ceramic 6, with its excellent high-frequency response characteristics and nanometer-level displacement accuracy, achieves significant expansion and contraction deformation on a microsecond-level timescale, providing micrometer-level and even nanometer-level fine displacement control for the experimental probe 7.

[0053] The probe portion of experimental probe 7 utilizes a universal ruby ​​ball-tipped probe 7, made of tungsten carbide and ruby. This material combination gives probe 7 extremely high hardness, ensuring that it does not deform during compression, thus guaranteeing the accuracy of displacement measurement. The ruby ​​ball tip is perfectly spherical, with a finely polished surface. During compression, the spherical probe ensures that contact stress is evenly distributed in the contact area, effectively preventing damage to the accelerometer under test due to stress concentration. Furthermore, this probe 7 system design has excellent adaptability, allowing for quick replacement of ruby ​​probe 7 of corresponding sizes to accommodate different sized accelerometer sensing elements. This greatly improves the flexibility and applicability of the experiment, making the measurement process more convenient and efficient. The completed experimental setup is shown below. Figure 2 As shown, its layout is reasonable and the components work together, laying a solid foundation for subsequent high-precision measurement experiments.

[0054] The second step is device setup. During the setup process, this experiment meticulously constructed a highly integrated and precisely coordinated measurement system, the core of which consists of a displacement module, a pressure control module, and a data collection module.

[0055] The displacement module consists of a high-precision six-axis displacement stage 1, a custom-designed crossbeam 5, a nanoscale micro-motion stage, a high-performance piezoelectric ceramic 6, and a special probe 7. The six-axis displacement stage 1 has multiple degrees of freedom, enabling translational and rotational movements. Fixed to a robust optical platform, it provides coarse adjustment of the overall macroscopic position. The custom-designed crossbeam 5 is connected to the six-axis displacement stage 1 at one end and to the nanoscale micro-motion stage at the other. Made of high-strength material, it ensures stability and prevents deformation during movement. The nanoscale micro-motion stage enables extremely small displacements, ensuring precise position adjustment of the probe 7. The piezoelectric ceramic 6 is tightly connected to the nanoscale micro-motion stage, featuring a high response frequency and high displacement resolution, capable of significant expansion and contraction deformation in a short time. The probe 7 is fixed to the piezoelectric ceramic 6. Its probe uses a ruby ​​ball head design with a finely machined surface, made of tungsten steel and ruby, exhibiting extremely high hardness to ensure no deformation due to contact force during measurement, thus guaranteeing measurement accuracy. The downward pressure control module mainly consists of the piezoelectric ceramic 6 and a high-performance drive circuit. The drive circuit provides a high-precision drive voltage, ensuring the rapid, accurate, and stable extension and retraction of the piezoelectric ceramic 6. By precisely controlling the output voltage waveform of the drive circuit, the extension and retraction process of the piezoelectric ceramic 6 can be precisely controlled, thereby precisely controlling the downward pressure and speed of the probe 7 on the cantilever beam. The data acquisition module consists of a low-noise preamplifier and a high-precision data acquisition card. The preamplifier features high input impedance, low noise, and wide bandwidth, enabling it to initially amplify the weak voltage signal output from the Wheatstone bridge on the cantilever beam while maintaining high signal fidelity. The data acquisition card can acquire the amplified voltage signal in real time, digitize it, and transmit it to the host computer. The host computer is equipped with professional data processing software that can display signal waveforms in real time, perform spectrum analysis, and store and process data, providing strong support for the accurate analysis of experimental data.

[0056] The entire device is rationally designed, with each module working collaboratively to ensure efficiency, stability, and reliability throughout the entire process, from precise positioning of probe 7 and accurate excitation of the cantilever beam to precise acquisition of vibration signals. This provides strong support for measuring the dynamic characteristics of high-stiffness cantilever beams. The third step involves device adjustment and operation, and data collection. Specific experimental steps are as follows:

[0057] Coarse adjustment of probe 7 position: Using the angular displacement stage function in the six-axis displacement stage 1, the angle of the crossbeam 5 is finely adjusted until the crossbeam 5 is in a horizontal state, ensuring that the stepping direction of the nano-micro stage is strictly perpendicular. At the same time, with the help of the multi-degree-of-freedom motion capability of the displacement stage 1, the experimental probe 7 is quickly and accurately coarsely adjusted to the vicinity of the cantilever beam under test, providing an initial position target that is close to the beam for subsequent precise positioning operations, effectively reducing the range and difficulty of subsequent adjustments.

[0058] The high-precision industrial camera 2 detects the relative position of probe 7 and the cantilever beam: The high-precision industrial camera 2, with its high-resolution imaging capabilities, clearly captures the relative position of probe 7 and the accelerometer. By observing the camera feed in real time, the various degrees of freedom of the six-axis displacement stage 1, including translation and rotation, are manually adjusted to gradually fine-tune the position and orientation of probe 7. This ensures that the downward pressure of probe 7 is aligned with the geometric center of the cantilever beam, providing crucial assurance for precise downward pressure at the center position.

[0059] Fine-tuning the probe 7 position: In the experiment, a high-precision industrial camera 2 with a 20-megapixel resolution and a frame rate of up to 60fps was first used. Its lens is equipped with a high numerical aperture objective lens with a numerical aperture of 0.95. Combined with a high-precision displacement device, probe 7 was moved to the center of the cantilever beam, ensuring that the axis of probe 7 was perpendicular to the plane of the cantilever beam. This industrial camera 2, based on a CMOS image sensor, has a 1 / 1.8-inch target surface size and a pixel size of 4.8μm × 4.8μm, enabling it to clearly capture the relative position of probe 7 and the accelerometer. Its imaging system has a 16-bit grayscale resolution, capable of resolving minute displacement changes of 0.01mm, providing precise visual feedback to the operator. Simultaneously, a high-precision displacement device was used. This device employs a closed-loop controlled piezoelectric nanostage with a linear accuracy of ±10nm and a repeatability of ±2nm, ensuring that the probe 7's downward pressure position is precisely aligned with the geometric center of the cantilever beam being measured. By adjusting the various degrees of freedom of the six-axis displacement stage 1, which employs a spherical hinge structure, the displacement accuracy of each axis is ±5μm, and the angular accuracy is ±0.005°, precise positioning of the probe 7 is achieved. This ensures that the axis of the probe 7 is strictly perpendicular to the plane of the cantilever beam, thereby guaranteeing the accuracy of the force transmission direction during the pressing process. After completing the above steps, by observing the reading changes of a precision balance 3 with a range of 0-100g and a scale division of 0.01mg, the operator can accurately determine the contact state between the probe 7 and the cantilever beam. Furthermore, by controlling the nano-microstage, which is driven by piezoelectric ceramic 6, has a displacement resolution of 0.1nm, a maximum stroke of 100μm, and uses a PID control algorithm for force feedback control, the contact force is adjusted to a minimum and stable level while ensuring contact between the probe 7 and the cantilever beam, ensuring the accuracy and reliability of the experimental process. The contact force control accuracy can reach ±0.1mN.

[0060] The cantilever beam is pressed down: An electric current is applied to the piezoelectric ceramic 6, whose natural frequency is 500kHz. When the experimental probe 7 adheres, its added mass and stiffness significantly affect the response rate of the piezoelectric ceramic 6. To accurately determine the extent of this influence and eliminate its interference with subsequent experiments, a high-precision capacitive sensor is used to calibrate the response time of the piezoelectric ceramic 6 before the formal experiment. The capacitive sensor has extremely high sensitivity and fast response capability. By measuring the change in surface charge of the piezoelectric ceramic 6, it can accurately capture the displacement response of the piezoelectric ceramic 6 under different voltage excitations, thus accurately calibrating its response time characteristics. After calibration, under the precise voltage output by the driving circuit, the piezoelectric ceramic 6 utilizes its excellent piezoelectric effect characteristics to rapidly convert electrical energy into mechanical energy, thereby achieving rapid elongation. In this process, the elongation of the piezoelectric ceramic 6 exhibits a highly linear relationship with the applied voltage, with a linear correlation coefficient exceeding 0.999. This highly linear relationship ensures precise displacement control. By precisely controlling the magnitude and rate of change of the driving voltage, micron-level or even submicron-level control of the elongation of the piezoelectric ceramic 6 can be achieved. The elongation response is rapid, completed in an extremely short time; specifically, its response time can be controlled within milliseconds or even shorter time ranges. In practical applications, when the driving voltage is applied at a frequency of 1 kHz, the piezoelectric ceramic 6 can reach its maximum elongation in approximately 0.5 milliseconds, thereby applying a rapid and precise downward pressure to the cantilever beam, ensuring that the cantilever beam undergoes deformation of a predetermined amplitude, creating conditions for subsequent free vibration. During this process, there is also a certain correspondence between the magnitude of the downward pressure of the piezoelectric ceramic 6 and the elongation. By precisely controlling the elongation, the downward pressure can be precisely adjusted, thereby ensuring that the deformation amplitude of the cantilever beam is within a predetermined range. This allows the cantilever beam to vibrate freely, with the piezoelectric ceramic 6 driving and exciting the free vibration of the cantilever beam.

[0061] To enable free vibration of the cantilever beam: After pressing down on the cantilever beam, a precisely controlled reverse voltage is applied to the piezoelectric ceramic 6. Under this reverse voltage, the piezoelectric ceramic 6 rapidly contracts and deforms, shortening by twice its previous elongation. This design ensures that the piezoelectric ceramic 6 can quickly retract within a very short time, allowing the probe 7 to quickly and cleanly disengage from the cantilever beam. Due to the extremely rapid disengagement, the cantilever beam instantly loses its external constraint, thus entering a state of free vibration under its own elastic restoring force. A schematic diagram of the cantilever beam vibration process is shown below. Figure 3 As shown.

[0062] Experimental Data Acquisition: At the back end of the experimental setup, a low-noise amplifier and a high-precision data acquisition card work together to accurately acquire the output voltage of the Wheatstone bridge on the cantilever beam. The amplifier employs an ultra-low noise preamplifier design, with an input noise density as low as 0.1 nV / √Hz, providing a 60 dB gain adjustment range over a wide frequency band of 1 kHz to 1 MHz. Butterworth filter banks suppress out-of-band noise interference, ensuring that the typical value of the weak electrical signal generated by the bridge is as low as μV. In the initial amplification stage, this effectively enhances the signal strength to the mV level while maintaining a signal-to-noise ratio above 80 dB. The amplifier's CMRR (Common Mode Rejection Ratio) reaches 120 dB, effectively suppressing the impact of power supply ripple and environmental electromagnetic interference on signal integrity. The data acquisition card is based on a 24-bit high-resolution ADC (Analog-to-Digital Converter), digitizing the amplified signal at a sampling rate of 1 MS / s. Its built-in Σ-Δ modulation architecture, combined with a decimation filtering algorithm, achieves 16-bit effective resolution and a dynamic range of 110 dB. The acquisition card locks experimental events with a synchronous clock and trigger system to ensure the timing accuracy of signal acquisition. Digital signals are stably uploaded to the host computer at a transmission rate of 1GB / s via a PCIe x4 high-speed interface. The host computer is equipped with dedicated signal processing software developed based on MATLAB R2023b, which uses wavelet transform combined with adaptive filtering algorithms to remove high-frequency noise and power frequency interference in real time, and uses Hilbert transform to extract signal envelope features. The software's built-in finite element analysis module, combined with Kalman filtering algorithm, reconstructs the deformation mode of the cantilever beam in real time, with extraction accuracy of key feature parameters, including natural frequency, damping coefficient, and time-varying strain distribution, better than 0.1%. The processed experimental data is stored in the host computer's NVMe solid-state storage array in ZFS file system format, supporting second-level indexing of 1TB of data and a read / write speed of 100MB / s. This provides a high-fidelity dataset for subsequent finite element model correction, modal parameter identification, and fatigue life prediction algorithm verification, ensuring the repeatability and engineering applicability of experimental conclusions.

[0063] The measurement process of this invention is as follows:

[0064] Device Platform Design: A robust and precise device platform architecture is constructed. A high-precision six-axis displacement stage 1 is rigidly connected to the piezoelectric ceramic 6, while the experimental probe 7 is securely fixed to the moving end of the piezoelectric ceramic 6, thus forming an efficient power transmission chain. The displacement stage 1 possesses excellent motion accuracy and stability, enabling the experimental probe 7 to achieve precise displacement in three-dimensional space, with displacement accuracy reaching the nanometer level. Specifically, the probe 7 is made of carefully selected ruby ​​ball head material, which features high hardness, high wear resistance, and good chemical stability. The appropriate size of the ruby ​​probe 7 can be flexibly replaced according to the specific dimensions of the sensitive unit of the accelerometer under test to adapt to different specifications of test samples. Furthermore, the ruby ​​ball head is a standard sphere, and its radius of curvature has been precisely calculated and optimized. When in contact with the cantilever beam, it can greatly reduce the stress distribution in the contact area, effectively avoiding damage to the accelerometer due to localized stress concentration, ensuring the safety and reliability of the testing process.

[0065] Device Construction and Module Division: After completing the platform design, the construction of the entire device commenced. This device adopts a modular design concept, mainly divided into three parts: a displacement module, a pressure control module, and a data acquisition module. Each module has a clear division of labor and collaborates effectively. The displacement module is organically combined with a six-axis displacement stage 1, a crossbeam 5, a nanometer micro-motion stage, a piezoelectric ceramic 6, and an experimental probe 7. The six-axis displacement stage 1 serves as a coarse adjustment mechanism, capable of quickly and accurately moving the probe 7 to the vicinity of the target area. Its wide displacement range covers a large spatial area of ​​the cantilever beam region. The nanometer micro-motion stage bears the responsibility of fine adjustment, further precisely adjusting the position of the probe 7 based on the six-axis displacement stage 1, achieving displacement control accuracy at the micrometer or even nanometer level. Simultaneously, it is responsible for precisely controlling the displacement and speed throughout the entire pressure process, ensuring the smoothness and controllability of the pressure action. The piezoelectric ceramic 6, as a key power component, is connected to the probe 7. The piezoelectric ceramic 6 is 335mm in size, has a rated voltage of 0-110V, and forms a close linkage with the six-axis displacement stage 1. It possesses extremely high response speed and displacement accuracy, capable of converting minute electrical signals into precise mechanical displacements, providing power support for the delicate operation of the probe 7. The core function of the downward control module is to apply precisely controlled positive and reverse voltages to both ends of the piezoelectric ceramic 6. By changing the magnitude and direction of the voltage, precise control of the extension and retraction behavior of the piezoelectric ceramic 6 is achieved, thereby precisely controlling the downward and release actions of the probe 7 on the cantilever beam. The data acquisition module mainly consists of a high sampling rate data acquisition card. Its task is to receive and acquire the voltage signal output from the Wheatstone bridge on the cantilever beam in real time. This data acquisition card features wide bandwidth and high resolution, accurately capturing weak signal changes during the vibration process of the cantilever beam, providing high-quality raw data for subsequent data analysis and processing.

[0066] Device Initialization and Probe Positioning: After the device is set up, the initialization preparation work before measurement begins. First, a high-precision industrial camera 2, in conjunction with a high-precision displacement device, is used to precisely position probe 7. Through the high-resolution imaging function of the industrial camera 2, the relative positional relationship between probe 7 and the cantilever beam is observed in real time. Based on the imaging results, the movement of the six-axis displacement stage 1 and the nanometer micro-motion stage is precisely controlled to move probe 7 accurately to the geometric center of the cantilever beam, with a positioning accuracy down to the micrometer level. Simultaneously, by precisely adjusting the movement of the displacement stage 1, the axis of probe 7 is ensured to be strictly perpendicular to the plane of the cantilever beam. This ensures that the direction of force transmission during subsequent pressing is consistent with the axial direction of the cantilever beam, reducing measurement errors introduced by force direction deviations. After adjusting the position of probe 7, the nano-micro stage is further fine-tuned by observing the changes in the reading of the precision balance 3, so that probe 7 gradually approaches the cantilever beam until the two just touch. At this time, the change in the reading of the balance 3 reaches the preset small threshold, thereby ensuring that the initial contact force between probe 7 and cantilever beam is extremely small and stable, avoiding adverse effects on the natural frequency test of cantilever beam due to excessive initial contact force.

[0067] Cantilever Beam Vibration Initiation: After completing the preliminary equipment debugging, parameter setting, and necessary calibration, the experiment officially entered the crucial cantilever beam vibration initiation and signal acquisition stage. First, a positive voltage was applied to the piezoelectric ceramic 6 using a DC power supply. Based on the piezoelectric effect principle, the piezoelectric ceramic 6 is a crystalline material with piezoelectric properties, and its internal electric dipoles are in equilibrium when not subjected to an external field. When a positive voltage is applied, the electric field direction is aligned with the polarization direction of the piezoelectric ceramic 6, causing the electric dipoles inside the piezoelectric ceramic 6 to undergo directional polarization. This polarization process causes the piezoelectric ceramic 6 to undergo significant elongation deformation along the electric field direction. The elongation is linearly related to the applied voltage, following the linear response law of the piezoelectric effect, i.e., the piezoelectric elongation ΔL can be calculated using the formula:

[0068] ΔL = d·E;

[0069] Where d is the piezoelectric constant and E is the electric field strength at the instant the voltage is applied.

[0070] The piezoelectric ceramic 6 rapidly elongates, and the resulting displacement is precisely transmitted to the end of the cantilever beam via a connected probe 7, applying a precisely controlled downward pressure to the cantilever beam. The magnitude of this downward pressure is proportional to the applied voltage. By precisely controlling the voltage value, the deformation amplitude of the cantilever beam can be precisely controlled to achieve a predetermined deformation amplitude. At this point, the deformation of the cantilever beam conforms to classical beam theory, and its stress distribution and deformation degree can be described by the Euler-Bernoulli beam equations.

[0071] Subsequently, a reverse voltage was applied to the piezoelectric ceramic 6 by rapidly switching the polarity of the power supply. Under the influence of the reverse electric field, the electric dipoles inside the piezoelectric ceramic 6 repolarized, with the polarization direction opposite to the initial polarization direction. This change in polarization direction caused the piezoelectric ceramic 6 to shorten rapidly along the direction of the electric field, and the amount of shortening also followed the linear response law of the piezoelectric effect. At this moment, the constraint force between the probe 7 and the cantilever beam instantly disappeared, and the cantilever beam quickly returned to its initial state under the action of its own elastic restoring force and began to vibrate freely. This free vibration process is the core part of the experiment, and its vibration frequency, amplitude, and other parameters will directly reflect the dynamic characteristics of the cantilever beam, providing important basic data for subsequent signal acquisition and analysis.

[0072] Data Acquisition: The Wheatstone bridge on the cantilever beam converts the minute strain during vibration into corresponding voltage signal changes. To improve signal quality and measurability, a high-performance amplifier is connected at the back end. This amplifier has a power supply range of ±3V to ±16V, a module bandwidth of 10MHz, a slew rate of 35V / µs, a gain range of 2 to 10000 times, a bias voltage adjustment range of VSS / 3 to VCC / 3, and an input impedance of 30GΩ||3pF. It amplifies the weak voltage signal output by the Wheatstone bridge, effectively handling noise and other information in the output signal. The amplified signal is acquired in real time by a high-speed data acquisition card and analyzed and processed by dedicated data processing software, thereby accurately calculating the natural frequency and other dynamic parameters of the cantilever beam, providing crucial data support for micro-nano scale dynamics research.

[0073] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-rigidity cantilever beam vibration initiation device, characterized in that, include: Cantilever beam support frame for supporting high-rigidity cantilever beams (4); The displacement module is equipped with an experimental probe (7) for contacting the high-rigidity cantilever beam; The pressure control module is connected to the displacement module and is used to control the experimental probe (7) to perform a pressure loading action to deform the high-stiffness cantilever beam and then perform a rapid separation action; The data acquisition module is used to acquire the free vibration signal generated by the high-stiffness cantilever beam after the experimental probe (7) separates from the high-stiffness cantilever beam.

2. The high-rigidity cantilever beam vibration initiation device according to claim 1, characterized in that, The displacement module includes a piezoelectric ceramic (6), and the pressure control module controls the voltage applied to the piezoelectric ceramic (6) to drive the experimental probe (7) to perform pressure loading and rapid separation actions.

3. The high-rigidity cantilever beam vibration initiation device according to claim 2, characterized in that, The displacement module also includes a displacement stage (1) and a crossbeam (5) fixed on the displacement stage (1). The piezoelectric ceramic (6) and the experimental probe (7) are connected to the displacement stage (1) through the crossbeam (5). The displacement stage (1) is used to adjust the macroscopic spatial position of the experimental probe (7).

4. The high-rigidity cantilever beam vibration initiation device according to claim 1, characterized in that, The displacement module also includes a multi-degree-of-freedom displacement stage (1) for macroscopically adjusting the position of the experimental probe (7) and a nanometer stage for microscopically adjusting the position.

5. The high-rigidity cantilever beam vibration initiation device according to claim 1, characterized in that, The device also includes a high-precision industrial camera (2) for observing and aligning the relative positions of the experimental probe (7) and the high-rigidity cantilever beam before they come into contact.

6. The high-rigidity cantilever beam vibration initiation device according to claim 1, characterized in that, The device also includes a precision balance (3) for measuring and controlling the initial contact force between the experimental probe (7) and the high-stiffness cantilever beam when they come into contact.

7. The high-rigidity cantilever beam vibration initiation device according to claim 1, characterized in that, The data acquisition module includes: A Wheatstone bridge integrated on the high-rigidity cantilever beam for converting vibration strain into a voltage signal; The amplifier connected to the Wheatstone bridge; A high-speed data acquisition card connected to the amplifier.

8. A high-rigidity cantilever beam vibration initiation device according to claim 7, characterized in that, The high-speed data acquisition card has a data sampling rate of no less than 1 MS / s and a data resolution of no less than 24 bits.

9. The high-rigidity cantilever beam vibration initiation device according to claim 1, characterized in that, The device also includes a host computer connected to the data acquisition module. The host computer is used to process the acquired free vibration signals and to determine the natural frequency of the high-stiffness cantilever beam.

10. A high-rigidity cantilever beam vibration initiation device according to claim 1, characterized in that, The tip of the experimental probe (7) is provided with a ball head made of a high-hardness wear-resistant material.

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