A micro-acceleration generating device based on magnetostrictive effect

Abstract

The application relates to the technical field of vibration generating devices, in particular to a micro acceleration generating device based on a magnetostrictive effect, which comprises a shell base, a magnetostrictive actuator, an inner shell base, a work platform, bottom and side vibration isolation springs, a guide assembly, a standard vibration sensor and a control module; the bottom vibration isolation springs are connected with the inner shell base and the shell base respectively, and the side vibration isolation springs are connected with the side walls of the inner and outer shell bases respectively; the magnetostrictive actuator is arranged in the inner shell base, the output rod upper end of the magnetostrictive actuator is in abutment with the work platform, and the standard vibration sensor is installed on the top end of the work platform installation part; the inner ring of the guide assembly is connected with the flange part, and the outer ring is connected with the inner shell base. The device can drive micro vibration with large current by using the characteristics of small displacement and large thrust of the magnetostrictive material, can eliminate electric noise interference, can guarantee high signal-to-noise ratio, and can realize non-contact friction axial guidance through elastic micro deformation of the diaphragm spring, so that the work platform only moves in the vertical direction with single degree of freedom.

Description

Technical Field

[0001] This invention relates to the field of vibration generating device technology, and in particular to a micro-acceleration generating device based on the magnetostrictive effect. Background Technology

[0002] Micro-vibration sensors are important devices for measuring weak vibration signals, and their measurement range is typically smaller than [the specified value]. Micro-vibration sensors are commonly used in aerospace and deep space exploration, seismic and geophysical research, high-end scientific experiments, high-precision navigation, and inertial measurement. The effective engineering application of micro-vibration sensors relies on their precise performance parameters; therefore, accurate calibration of the relevant characteristics of micro-vibration sensors used in these research fields is a prerequisite for their correct application.

[0003] Micro-accelerometers are an important component of micro-vibration sensor calibration systems and are typically implemented using electromagnetic vibration tables. Electromagnetic vibration tables utilize the principle that a current-carrying coil experiences Ampere force in a magnetic field to generate vibration, and the vibration required is controlled by adjusting the input current of the current-carrying coil. Current micro-accelerometers mainly suffer from the following technical bottlenecks: (1) Severe electromagnetic noise interference: Conventional electromagnetic vibration tables must significantly reduce the input current when outputting small vibrations. The extremely small input current is easily overwhelmed by the electrical noise of the system, resulting in a significant reduction in the signal-to-noise ratio of the output acceleration waveform. (2) Waveform distortion caused by mechanical friction: Existing vibration tables (such as conventional guide rail structure micro-vibration tables) experience severe nonlinear distortion in the output waveform due to static and dynamic friction between structural components when moving at a microscale (micrometer-level displacement), introducing high-order harmonics and making it impossible to obtain a pure micro-acceleration sinusoidal signal.

[0004] Magnetostriction is the phenomenon of reversible mechanical strain in ferromagnetic materials under the action of an external magnetic field. With the development of new magnetostrictive materials (such as Terfenol-D and Galfenol), magnetostrictive technology has been widely studied in the field of high-precision drive. Magnetostrictive actuators have the following characteristics: (1) wide frequency response; (2) good linearity under bias magnetic field and prestress conditions; (3) small micron-level output displacement requires large driving current, so the influence of current noise on output displacement is small.

[0005] However, magnetostrictive technology has not yet been applied in the field of micro-accelerometers. Furthermore, if a conventional magnetostrictive actuator is used only as a thrust source to directly drive a load, without precise guidance, it is highly susceptible to producing minute lateral deflections or swaying. In micro-accelerometer calibration, even extremely small lateral cross-couplings can cause fatal error interference to the sensor being calibrated. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a micro-acceleration generating device based on the magnetostrictive effect, which can realize micro-vibration by driving with a large current, suppressing electrical noise interference at the source, and eliminating waveform distortion by adopting a frictionless guiding structure.

[0007] This invention is implemented as follows:

[0008] The present invention provides a micro-acceleration generating device based on the magnetostrictive effect, comprising an outer shell base, a magnetostrictive actuator, an inner shell base, a working platform, a bottom vibration isolation spring, a side vibration isolation spring, a guide assembly, a standard vibration sensor, and a control module;

[0009] The inner shell base is located inside the outer shell base;

[0010] The upper end of the bottom vibration isolation spring is connected to the inner shell base, and the lower end is connected to the outer shell base;

[0011] One end of the side vibration isolation spring is connected to the side wall of the inner shell base, and the other end is connected to the side wall of the outer shell base.

[0012] The magnetostrictive actuator is installed inside the inner shell base. The magnetostrictive actuator has an output rod. The working platform is composed of a flange and a mounting part. The upper end of the output rod abuts against the flange. The mounting part extends to the outside of the outer shell base. A standard vibration sensor is installed at the top of the mounting part.

[0013] The guide assembly is a diaphragm spring, with the inner ring of the diaphragm spring connected to the flange portion and the outer ring connected to the inner shell base;

[0014] The control module is connected to a standard vibration sensor and a magnetostrictive actuator.

[0015] Furthermore, the guide assembly includes two diaphragm springs, which are arranged vertically opposite each other and parallel to each other. The inner ring of one diaphragm spring is connected to the upper end of the flange, and the inner ring of the other diaphragm spring is connected to the lower end of the flange.

[0016] Furthermore, the inner shell base is composed of a bottom shell, a middle shell and an upper shell. After the upper shell and the middle shell are connected by a first screw, the outer ring of one of the diaphragm springs is fixed between the upper shell and the middle shell.

[0017] After the middle shell and the bottom shell are connected by the second screw, the outer ring of the other diaphragm is fixed between the middle shell and the bottom shell.

[0018] Furthermore, the upper end of the output rod is provided with a spherical force transmission head, and the bottom end of the flange is provided with a spherical groove, the spherical force transmission head abutting against the spherical groove.

[0019] Furthermore, the magnetostrictive actuator includes a housing, a magnetic conductive assembly, an excitation coil, an upper magnetic conductor, a lower magnetic conductor, a magnetostrictive rod, and a disc spring;

[0020] The housing is installed inside the inner shell base, and the magnetic conductive assembly is located inside the housing; the magnetic conductive assembly has a through hole at its center, and the lower magnetic conductor, magnetostrictive rod and upper magnetic conductor are installed in the through hole from bottom to top.

[0021] The inner side of the magnetic conductive component has an installation space, the excitation coil is located in the installation space, and the excitation coil is wrapped around the outside of the magnetostrictive rod.

[0022] The output rod is mounted on the top of the upper magnetic conductor, and the disc spring is sleeved on the outer wall of the output rod. The outer wall of the output rod is provided with a shoulder. The lower end of the disc spring abuts against the shoulder, and the upper end abuts against the top wall of the housing.

[0023] Furthermore, the magnetic conductive assembly includes a lower magnetic conductive ring, a side magnetic conductive ring, and an upper magnetic conductive ring, which are installed sequentially inside the housing from bottom to top.

[0024] Furthermore, the excitation coil is composed of a bias coil and a drive coil;

[0025] The control module includes a signal generator, a data acquisition unit, a power amplifier, a DC driver, a preamplifier, and a computer.

[0026] The bias coil is connected to a DC driver;

[0027] The drive coil is connected to a power amplifier, the power amplifier is connected to a signal generator, and the signal generator is connected to a computer.

[0028] The standard vibration sensor is connected to a preamplifier, which is connected to a computer via a data acquisition unit.

[0029] The beneficial effects of this invention are as follows:

[0030] 1. This device utilizes the characteristics of magnetostriction, which has extremely small output displacement but extremely large thrust, allowing for the use of large current to drive minimal vibrations, eliminating electrical noise interference, and thus maintaining an extremely high electrical signal-to-noise ratio.

[0031] 2. This device uses diaphragm springs to suspend and support the working platform. The axial guidance of the working platform is achieved by utilizing the elastic micro-deformation of the diaphragm material, realizing non-contact friction between structural components. At the same time, the diaphragm spring has the characteristics of extremely high radial stiffness and low axial stiffness, which can strictly limit the movement of the working platform to a single vertical degree of freedom, eliminating lateral sway and crosstalk. It also provides vertical preload.

[0032] 3. This invention matches the high thrust output of the magnetostrictive actuator with the large mass of the working platform and the impedance characteristics of the diaphragm springs, constructing a mechanical low-pass filter that effectively isolates the high-frequency parasitic resonance of the magnetostrictive actuator itself. Simultaneously, the two parallel diaphragm springs eliminate the microscopic lateral swaying caused by thermal expansion and contraction or uneven magnetization of the magnetostrictive actuator material, ensuring the absolute vertical uniformity of the micro-acceleration direction.

[0033] 4. The bottom vibration isolation spring and the side vibration isolation spring constitute the vibration isolation spring. After external interference is transmitted from the external body to the outer shell base, it is attenuated to the inner shell base by the vibration isolation spring, so that the device can more effectively isolate external micro-vibration interference while generating micro-vibration that meets the requirements.

[0034] 5. The combination of the spherical force transmission head at the upper end of the output rod and the spherical groove at the lower end of the working platform can compensate for assembly coaxiality errors, reduce the transmission of lateral force and bending moment to the magnetostrictive actuator, and improve the linear output performance and service life of the magnetostrictive actuator. Attached Figure Description

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] Figure 1 This is a schematic diagram of a micro-acceleration generating device based on the magnetostrictive effect in this invention.

[0037] Figure 2 This is a schematic diagram of the structure of a micro-acceleration generating device based on the magnetostrictive effect in this invention, with the control module omitted.

[0038] Figure 3 This is a schematic diagram of the connection structure between the magnetostrictive actuator and the working platform in this invention.

[0039] Explanation of the labels in the diagram:

[0040] 1. Inner shell base; 101. Bottom shell; 102. Middle shell; 103. Upper shell; 2. Working platform; 201. Flange; 202. Mounting part; 203. Spherical groove; 3. Output rod; 301. Spherical force transmission head; 302. Shoulder; 4. Upper magnetic ring; 5. Excitation coil; 6. Side magnetic ring; 7. Bottom vibration isolation spring; 8. Computer; 9. Diaphragm spring; 10. Side vibration isolation spring; 11. Disc spring; 12. Upper magnetic conductor; 13. Magnetostrictive rod; 14. Lower magnetic conductor; 15. Lower magnetic ring; 16. Housing; 17. Outer shell base; 18. Standard vibration sensor; 19. Signal generator; 20. Data acquisition instrument; 21. Power amplifier; 22. DC driver; 23. Preamplifier; 24. Installation space; 25. Micro-vibration sensor to be calibrated. Detailed Implementation

[0041] Please see Figures 1 to 3 The present invention provides a micro-acceleration generating device based on the magnetostrictive effect, including an outer shell base 17, a magnetostrictive actuator, an inner shell base 1, a working platform 2, a bottom vibration isolation spring 7, a side vibration isolation spring 10, a guide assembly, a standard vibration sensor 18, and a control module; the outer shell base 17 is fixed on the ground or a vibration-damping foundation.

[0042] The inner shell base 1 is located inside the outer shell base 17;

[0043] The upper end of the bottom vibration isolation spring 7 is connected to the inner shell base 1, and the lower end is connected to the outer shell base 17;

[0044] One end of the side vibration isolation spring 10 is connected to the side wall of the inner shell base 1, and the other end is connected to the side wall of the outer shell base 17.

[0045] The magnetostrictive actuator is installed inside the inner shell base 1. The magnetostrictive actuator has an output rod 3. The working platform 2 is composed of a flange portion 201 and a mounting portion 202. The upper end of the output rod 3 abuts against the flange portion 201. The mounting portion 202 extends to the outer side of the outer shell base 17. A standard vibration sensor 18 is installed at the top of the mounting portion 202. The standard vibration sensor 18 is used to detect the micro-vibration of the working platform 2. The top of the working platform 2 is also used to install the micro-vibration sensor 25 to be calibrated.

[0046] The output rod 3 is made of a non-magnetic material. The output rod 3 is used to effectively transmit the small axial displacement generated by the magnetostrictive rod 13 to the external load. At the same time, the output rod 3 supported by the non-magnetic material can also avoid participating in the magnetic circuit to form a magnetic flux bypass.

[0047] The guide component is a diaphragm spring 9, the inner ring of which is connected to the flange portion 201, and the outer ring is connected to the inner shell base 1;

[0048] The control module is connected to the standard vibration sensor 18 and the magnetostrictive actuator.

[0049] Specifically, the guide assembly includes two diaphragm springs 9, which are arranged vertically opposite each other and parallel to each other. The inner ring of one diaphragm spring 9 is connected to the upper end of the flange portion 201, and the inner ring of the other diaphragm spring 9 is connected to the lower end of the flange portion 201.

[0050] Specifically, the inner shell base 1 is composed of a bottom shell 101, a middle shell 102 and an upper shell 103. After the upper shell 103 and the middle shell 102 are connected by a first screw, the outer ring of one of the diaphragm springs 9 is fixed between the upper shell 103 and the middle shell 102.

[0051] After the middle shell 102 and the bottom shell 101 are connected by the second screw, the outer ring of the other diaphragm is fixed between the middle shell 102 and the bottom shell 101.

[0052] Specifically, the upper end of the output rod 3 is provided with a spherical force transmission head 301, and the bottom end of the flange portion 201 is provided with a spherical groove 203, and the spherical force transmission head 301 abuts against the spherical groove 203.

[0053] Specifically, the magnetostrictive actuator also includes a housing 16, a magnetic conductive assembly, an excitation coil 5, an upper magnetic conductor 12, a lower magnetic conductor 14, a magnetostrictive rod 13, and a disc spring 11;

[0054] The housing 16 is installed inside the inner housing base 1, and the magnetic conductive assembly is located inside the housing 16. The magnetic conductive assembly has a through hole at its center, and the lower magnetic conductor 14, the magnetostrictive rod 13, and the upper magnetic conductor 12 are installed in the through hole from bottom to top.

[0055] The inner side of the magnetic conductive component has an installation space 24, the excitation coil 5 is disposed in the installation space 24, and the excitation coil 5 surrounds the outer side of the magnetostrictive rod 13.

[0056] The output rod 3 is mounted on the top of the upper magnet 12. The disc spring 11 is sleeved on the outer wall of the output rod 3. The outer wall of the output rod 3 has a shoulder 302. The lower end of the disc spring 11 abuts against the shoulder 302, and the upper end abuts against the top wall of the housing 16. The disc spring 11 applies continuous axial compressive stress to the magnetostrictive rod 13, keeping it always in the optimal working range of unidirectional compression, avoiding damage due to tension or nonlinearity of the magnetization curve.

[0057] Specifically, the magnetic conductive assembly includes a lower magnetic conductive ring 15, a side magnetic conductive ring 6, and an upper magnetic conductive ring 4, which are installed sequentially inside the housing 16 from bottom to top.

[0058] Specifically, the excitation coil 5 consists of a bias coil and a drive coil;

[0059] The control module includes a signal generator 19, a data acquisition unit 20, a power amplifier 21, a DC driver 22, a preamplifier 23, and a computer 8;

[0060] The bias coil is connected to the DC driver 22;

[0061] The drive coil is connected to the power amplifier 21, the power amplifier 21 is connected to the signal generator 19, and the signal generator 19 is connected to the computer 8;

[0062] The standard vibration sensor 18 is connected to the preamplifier 23, and the output of the preamplifier 23 is sent to the data acquisition instrument 20, which is connected to the computer 8.

[0063] like Figure 2 As shown, the excitation coil 5 is located in a closed magnetic circuit formed by the upper magnetic conductor 12, the lower magnetic conductor 14, the magnetic conductor assembly, the magnetostrictive rod 13, and the air gap.

[0064] When the drive coil is energized, it generates a controllable alternating magnetic field, which is used to adjust the extension and retraction of the magnetostrictive rod 13.

[0065] When the bias coil is energized, it can provide a stable DC bias magnetic field, so that the operating point of the magnetostrictive rod 13 is in the linear high-sensitivity region of the hysteresis curve, thereby improving the linearity, response sensitivity and output efficiency of the actuator.

[0066] Before the calibration test, the micro-vibration sensor 25 to be calibrated and the standard vibration sensor 18 are mounted on the top of the worktable. During the test, the DC driver 22 first outputs the required current to the bias coil to generate a constant static magnetic field. Then, the test parameters, such as the vibration frequency and amplitude, are input into the computer 8. After processing these parameters, the computer 8 sends control commands to the signal generator 19 through its interface. The signal generator 19 then generates a signal with the set frequency and voltage amplitude. This signal is amplified by the power amplifier 21 and output to the drive coil in the excitation coil 5, thereby causing the magnetostrictive actuator to vibrate and further driving the worktable 2 to produce the required micro-vibration.

[0067] A standard vibration sensor 18 mounted on the work platform 2 is used to test the vibration signal. The signal is amplified by a preamplifier 23 and output to a data acquisition unit 20, which then transmits it to a computer 8 via an interface. The software on the computer 8 adjusts the output voltage amplitude of the signal generator 19 according to whether the preset vibration level has been reached, until the output vibration level is within the allowable error range of the preset vibration level.

[0068] Once the working platform 2 reaches the preset vibration level, the computer 8 collects data from the standard vibration sensor 18 and the micro vibration sensor 25 to be calibrated, in order to calibrate the micro vibration sensor 25.

[0069] Unlike existing micro-accelerometers, the micro-accelerometer in this invention can generate a smaller displacement and thus a smaller acceleration under the same driving current. A satisfactory micro-accelerometer signal can be generated by controlling the input current. Furthermore, the output acceleration amplitude is further reduced by increasing the mass of the working platform 2. Simultaneously, the preload of the disc spring 11 and the gravity of the working platform 2 ensure that the non-magnetic output rod 3 remains in contact with the working platform 2. The output signal is controlled by the input current signal of the excitation coil 5. The disc spring 11 of the non-magnetic output rod 3 provides a certain axial preload, allowing the magnetostrictive rod 13 to fully utilize the material's properties.

[0070] In addition, in this invention, the inner shell base 1 and the outer shell base 17 are connected by a vibration isolation spring, and the working platform 2 and the inner shell base 1 are connected by a diaphragm spring 9. After external interference is transmitted from the external body to the outer shell base 17, the external vibration interference is attenuated to the inner shell base 1 by the vibration isolation spring. External vibration interference can be isolated by reasonably setting the spring stiffness.

[0071] Unlike traditional platform structures that directly push the load with a magnetostrictive actuator, this invention does not treat the magnetostrictive actuator itself as an independent and complete vibration generator. Instead, it uses it as an excitation source with high signal-to-noise ratio, wide bandwidth, and good linearity. The magnetostrictive actuator is combined with a frictionless flexible guide structure, a mechanical filtering mechanism, and a vibration isolation structure to construct a system-level structure suitable for micro-acceleration output.

[0072] In this invention, a large current is used to drive minimal vibrations, eliminating electrical noise interference. Specifically, unlike conventional moving-coil (electromagnetic) micro-accelerometers that require extremely small currents for drive (making them highly susceptible to electrical noise interference), this device utilizes the characteristics of magnetostriction, which results in extremely small output displacement but extremely large thrust, allowing for the use of large currents for drive, thereby maintaining an extremely high electrical signal-to-noise ratio.

[0073] This invention also enables zero-friction guidance to eliminate waveform distortion. Specifically, this invention employs a frictionless and parallel diaphragm spring 9 suspension support structure, completely eliminating traditional contact supports or disc spring supports with static friction and nonlinear sliding. At micro-vibration outputs at the micrometer or even nanometer level, low-frequency friction creep is eliminated, ensuring extremely low total harmonic distortion.

[0074] A standalone actuator cannot be directly used as a calibration source. This invention matches the high thrust output of the actuator with the impedance characteristics of the large mass of the working platform 2 and the diaphragm spring 9, constructing a mechanical low-pass filter that effectively isolates the high-frequency parasitic resonance of the magnetostrictive actuator itself. At the same time, the diaphragm spring 9 eliminates the microscopic lateral swaying caused by thermal expansion and contraction or uneven magnetization of the magnetostrictive actuator material, ensuring the absolute vertical uniformity of the micro-acceleration direction.

[0075] The bottom vibration isolation spring and the side vibration isolation spring constitute the vibration isolation spring. After external interference is transmitted from the external body to the outer shell base 17, it is attenuated to the inner shell base 1 through the vibration isolation support, so that the device can more effectively isolate external micro-vibration interference while generating micro-vibration that meets the requirements.

[0076] The combination of the spherical force transmission head at the upper end of the output rod 3 (made of non-magnetic material) and the spherical groove 203 at the lower end of the working platform 2 can compensate for assembly coaxiality errors, reduce the transmission of lateral force and bending moment to the magnetostrictive actuator, and improve the linear output performance and service life of the actuator.

[0077] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and not intended to limit the scope of the present invention. Equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A micro-acceleration generating device based on the magnetostrictive effect, characterized in that: It includes an outer shell base, a magnetostrictive actuator, an inner shell base, a working platform, bottom vibration isolation springs, side vibration isolation springs, a guide assembly, a standard vibration sensor, and a control module; The inner shell base is located inside the outer shell base; The upper end of the bottom vibration isolation spring is connected to the inner shell base, and the lower end is connected to the outer shell base; One end of the side vibration isolation spring is connected to the side wall of the inner shell base, and the other end is connected to the side wall of the outer shell base. The magnetostrictive actuator is installed inside the inner shell base. The magnetostrictive actuator has an output rod. The working platform is composed of a flange and a mounting part. The upper end of the output rod abuts against the flange. The mounting part extends to the outside of the outer shell base. The standard vibration sensor is installed at the top of the mounting part. The guide assembly is a diaphragm spring, with the inner ring of the diaphragm spring connected to the flange portion and the outer ring connected to the inner shell base; The control module is connected to the standard vibration sensor and the magnetostrictive actuator.

2. The micro-acceleration generating device based on magnetostrictive effect as described in claim 1, characterized in that: Two diaphragm springs are provided, arranged vertically opposite each other and parallel to each other. The inner ring of one diaphragm spring is connected to the upper end of the flange, and the inner ring of the other diaphragm spring is connected to the lower end of the flange.

3. The micro-acceleration generating device based on magnetostrictive effect as described in claim 2, characterized in that: The inner shell base is composed of a bottom shell, a middle shell and an upper shell. After the upper shell and the middle shell are connected by a first screw, the outer ring of one of the diaphragm springs is fixed between the upper shell and the middle shell. After the middle shell and the bottom shell are connected by a second screw, the outer ring of another diaphragm spring is fixed between the middle shell and the bottom shell.

4. The micro-acceleration generating device based on magnetostrictive effect as described in claim 1, characterized in that: The upper end of the output rod is provided with a spherical force transmission head, and the bottom end of the flange is provided with a spherical groove, with the spherical force transmission head abutting against the spherical groove.

5. A micro-acceleration generating device based on magnetostrictive effect as described in claim 1, characterized in that: The magnetostrictive actuator includes a housing, a magnetic conductive assembly, an excitation coil, an upper magnetic conductor, a lower magnetic conductor, a magnetostrictive rod, and a disc spring. The housing is installed inside the inner shell base, and the magnetic conductive assembly is disposed inside the housing; the magnetic conductive assembly has a through hole at its center, and the lower magnetic conductor, the magnetostrictive rod, and the upper magnetic conductor are installed sequentially from bottom to top in the through hole; The magnetic conductive assembly has an installation space on its inner side, the excitation coil is disposed in the installation space, and the excitation coil surrounds the outer side of the magnetostrictive rod. The output rod is mounted on the top of the upper magnetic conductor, and the disc spring is sleeved on the outer wall of the output rod. The outer wall of the output rod is provided with a shoulder. The lower end of the disc spring abuts against the shoulder, and the upper end abuts against the top wall of the housing.

6. The micro-acceleration generating device based on magnetostrictive effect as described in claim 5, characterized in that: The magnetic conductive assembly includes a lower magnetic conductive ring, a side magnetic conductive ring, and an upper magnetic conductive ring, which are installed sequentially inside the housing from bottom to top.

7. A micro-acceleration generating device based on magnetostrictive effect as described in claim 5, characterized in that: The excitation coil consists of a bias coil and a drive coil; The control module includes a signal generator, a data acquisition unit, a power amplifier, a DC driver, a preamplifier, and a computer. The bias coil is connected to the DC driver; The drive coil is connected to the power amplifier, the power amplifier is connected to the signal generator, and the signal generator is connected to the computer; The standard vibration sensor is connected to the preamplifier, and the preamplifier is connected to the computer via the data acquisition instrument.

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