Low-frequency micro-vibration sensing and actuating integrated device

Abstract

A low-frequency micro-vibration sensing and actuating integrated device disclosed by the present invention comprises a top member, a voice coil actuator, a low-frequency dynamic force sensor and a bottom member, the voice coil actuator comprises magnetic steel and a voice coil, the voice coil is installed on the bottom member, the magnetic steel is installed on the top member, one end of the low-frequency dynamic force sensor is connected with the voice coil, and the other end of the low-frequency dynamic force sensor is connected with the bottom member. The other end is connected with the magnetic steel; the low-frequency dynamic force sensor is coaxially connected with the voice coil actuator; the low-frequency dynamic force sensor comprises a semiconductor strain gauge serving as a measuring element, a polyurethane material serving as an elastic element and a composite full-bridge circuit serving as a measuring circuit. According to the low-frequency micro-vibration sensing and actuating integrated device, the low-frequency dynamic force sensor and the voice coil actuator are effectively combined together, the two functions of low-frequency vibration measurement and actuating force output can be provided at the same time, the performance of the sensor and the stability of the actuator are improved, and therefore the vibration isolation performance of the device is improved; and the environment requirement for severe space can be met, and the cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of spatial low-frequency measurement and active vibration isolation, and specifically relates to a low-frequency micro-vibration sensing and actuating integrated device. Background Art

[0002] During the on-orbit operation of a spacecraft, the payload carried on it will be affected by the disturbance force of space micro-vibration. The frequencies of low-frequency micro-vibrations, such as the vibration of flexible accessories, the vibration of flexible solar sails, and the sweep of optical cameras, are mainly concentrated in the range of 0.01 to 10 Hz. Low-frequency micro-vibrations will have a significant impact on important performance indicators such as pointing accuracy, stability, and resolution of space precision payloads. Therefore, conducting research on low-frequency micro-vibration measurement and active vibration isolation technology in space is one of the important technologies to ensure the reliable operation of precision payloads.

[0003] Low-frequency dynamic force sensors are an important way to measure low-frequency micro-vibrations. At present, low-frequency dynamic force sensors mainly include piezoelectric and resistive strain sensors. The signal generated by the piezoelectric sensor is weak and the output impedance is high. The high output impedance needs to be converted into a low output impedance and then amplified by charge before it can be collected. When performing static measurements, the amount of charge is easily lost. After a period of time, the functional relationship between the amount of charge and the pressure will change. Therefore, the lower the measured frequency, the more the output voltage sensitivity deviates from the ideal state, and the greater the error in sensitivity and phase angle. Strain sensors are mainly used to measure static and quasi-static forces, and are widely used because of their simple design and stable and reliable performance. However, there is still a problem of insufficient sensitivity in measuring dynamic forces. Therefore, this field urgently needs a device suitable for low-frequency micro-vibration measurement and active vibration isolation in space to ensure the reliable operation of precision loads in space. Summary of the invention

[0004] In view of this, the present invention proposes a low-frequency micro-vibration sensing and actuation integrated device. The low-frequency dynamic force sensor adopts the strain measurement principle to convert the low-frequency dynamic force received into an electrical signal for strain collection. A semiconductor strain gauge with a higher sensitivity coefficient than an ordinary strain gauge is used as a measuring element, a polyurethane material with an elastic modulus much lower than that of metal is used as an elastic element, and a composite full-bridge circuit is used as a measuring circuit, which can effectively improve the sensitivity of the sensor and can achieve accurate measurement of 0.01-10Hz low-frequency signals. The voice coil actuator outputs the corresponding force according to the signal provided by the controller. The voice coil actuator has the advantages of fast response, high precision, low energy consumption, etc., and can achieve precise control of the force value. The present invention integrates the low-frequency dynamic force sensor with the voice coil actuator to achieve accurate measurement and response to the low-frequency dynamic force of the installation platform.

[0005] On the one hand, the present invention provides a low-frequency micro-vibration sensing and actuation integrated device, characterized in that it includes: a top component, a voice coil actuator, a low-frequency dynamic force sensor and a bottom component, the voice coil actuator includes a magnet and a voice coil, the voice coil is installed on the bottom component, the magnet is installed on the top component, one end of the low-frequency dynamic force sensor is connected to the voice coil, and the other end is connected to the magnet; the low-frequency dynamic force sensor is coaxially connected to the voice coil actuator; the low-frequency dynamic force sensor includes a semiconductor strain gauge as a measuring element, a polyurethane material as an elastic element, and a composite full-bridge circuit as a measuring circuit.

[0006] Furthermore, the voice coil is mounted on the bottom member through bolts, the magnet is mounted on the top member through bolts, one end of the low-frequency dynamic force sensor is connected to the voice coil through bolts, and the other end is connected to the magnet through epoxy glue.

[0007] Furthermore, the semiconductor strain gauge is a TP-5 semiconductor strain gauge made of single crystal silicon.

[0008] Furthermore, the outer diameter of the semiconductor strain gauge is 15 mm and the height is 30 mm.

[0009] Furthermore, the elastic modulus of the polyurethane material is 4.1×10 7 Pa.

[0010] Furthermore, the composite full-bridge circuit uses eight semiconductor strain gauges symmetrically pasted around the elastic element.

[0011] Furthermore, the magnetic steel includes a permanent magnet and a stator core, the permanent magnet is a neodymium iron boron permanent magnet N42SH, and the stator core is stainless steel, with a steel grade of 2Cr13.

[0012] Furthermore, the voice coil comprises a coil and a voice coil frame. The coil adopts an annular multilayer winding and is wound with high-strength enameled wire QY-2 / 220. The voice coil frame material is 6061 aluminum alloy.

[0013] Furthermore, the coil is connected to the magnet through the low-frequency dynamic force sensor, and the height H of the voice coil and the gap h between the voice coil and the magnet are designed according to vibration isolation requirements, thereby ensuring that the movement stroke of the voice coil actuator is h.

[0014] On the other hand, the present invention further provides an active vibration isolation device, which includes the low-frequency micro-vibration sensor and actuation integrated device of the present invention, a power supply, a signal conditioner, a real-time controller and a voice coil driver, the power supply is used to provide power for the active vibration isolation device, the signal conditioner is data-connected with the low-frequency micro-vibration sensor and actuation integrated device and the real-time controller, the real-time controller is further electrically connected with the voice coil driver, and the voice coil driver is further electrically connected with the low-frequency micro-vibration sensor and actuation integrated device;

[0015] The working process of the active vibration isolation device is as follows: when the top component is disturbed by the dynamic force F, the low-frequency dynamic force sensor is deformed by the force, and the force value signal is converted into a voltage and transmitted to the signal conditioner; the signal conditioner outputs the signal to the real-time controller to collect the information of the force value F applied to the low-frequency dynamic force sensor in real time; the real-time controller outputs the control current to the voice coil driver through the calculation of the control algorithm, thereby driving the voice coil actuator to output the control force to control the vibration of the top component, so as to achieve a stable state of the top component.

[0016] The sensing vibration isolation system includes a sensor for measurement and an actuator for outputting force. When designing the vibration isolation system, it is necessary not only to design the structure of the sensor and the actuator separately but also to design their installation positions. The low-frequency micro-vibration sensing and actuation integrated device of the present invention effectively combines the sensor and the actuator together, and can provide two functions of low-frequency vibration measurement and actuation force output at the same time, which is convenient for the development of the vibration isolation system.

[0017] The low-frequency micro-vibration sensor and actuation integrated device designed by the present invention can accurately measure the low-frequency force value information of 0.01-10Hz and can control the vibration of the installation platform. This makes the present invention have the following beneficial effects in practical applications compared with the prior art:

[0018] 1. Improve sensor performance: The device uses semiconductor strain gauges as measuring elements, polyurethane materials as elastic elements, and composite full-bridge circuits as measuring circuits, so that the sensor sensitivity reaches 0.33V / N and the measurement frequency reaches 0.01Hz.

[0019] 2. Improve the vibration isolation performance of the device: The device can not only measure the force information of the installation platform, but also output the force value to actively isolate the installation platform from vibration. The polyurethane material connecting the sensor and the actuator has spring and damping characteristics, and can also perform passive vibration isolation on the installation platform.

[0020] 3. Improve the stability of the actuator: The magnetic steel and coil parts of the voice coil actuator are connected by the elastic element of the sensor, which has great damping itself, which can improve the passive vibration isolation performance, reduce the difficulty of active vibration isolation algorithm design, and reduce the occurrence of failures.

[0021] 4. Improve the environmental adaptability of the device: All materials in the device can adapt to the environmental requirements of -45 to +100°C and can meet the severe environmental requirements of space.

[0022] 5. Reduce costs: The price of semiconductor strain gauges used in sensors is similar to that of ordinary strain gauges. The material cost and processing cost of polyurethane elastic elements are much lower than those of metal elastic elements. The magnets and coils used in voice coil actuators are mature processes. Therefore, the cost of low-frequency micro-vibration sensing and actuation integrated devices can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a perspective view of the composition and connection mode of the low-frequency sensing and actuating integrated device of the present invention.

[0024] Figure 2 It is a structural schematic diagram of the low-frequency sensing and actuating integrated device of the present invention.

[0025] Figure 3 It is the front view and the cross-sectional view of the low-frequency sensing and actuating integrated device of the present invention.

[0026] Figure 4 It is a structural schematic diagram of the low-frequency dynamic force sensor of the present invention.

[0027] Figure 5 It is a schematic diagram of the elastic element in the low-frequency dynamic force sensor of the present invention.

[0028] Figure 6 It is a schematic diagram of the pasting position of the semiconductor strain gauge in the present invention.

[0029] Figure 7 It is a schematic diagram of the wiring circuit of the semiconductor strain gauge in the present invention.

[0030] Figure 8 It is a structural schematic diagram of the magnetic steel in the present invention.

[0031] Fig. 9 It is the main view and cross-sectional view of the magnetic steel in the present invention.

[0032] Fig.10 It is a structural schematic diagram of the voice coil in the present invention.

[0033] Fig.11 It is a front view and a cross-sectional view of the voice coil in the present invention.

[0034] Fig.12 It is a design position diagram of the voice coil actuator of the present invention.

[0035] Fig.13 It is a schematic diagram of the working process of the active vibration isolation device including the low-frequency micro-vibration sensing and actuating integrated device of the present invention.

[0036] In the figure: 1-stator core, 2-permanent magnet, 3-coil, 4-voice coil frame, 5-bottom member, 6-elastic element, 7-semiconductor strain gauge, 8-top member. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in more detail below with reference to the accompanying drawings, but the present invention is not limited thereto.

[0038] The present invention designs a low-frequency dynamic force sensor based on the strain measurement principle, designs a voice coil actuator based on the electromagnetic principle, and designs the low-frequency dynamic force sensor and the voice coil actuator into an integrated structure, which can also provide force value output during the dynamic force measurement process.

[0039] The structural perspective view of the low-frequency micro-vibration sensor and actuation integrated device designed by the present invention is as follows Figure 1 As shown. The low-frequency micro-vibration sensing and actuating integrated device includes a voice coil actuator and a low-frequency dynamic force sensor. The voice coil actuator includes a magnetic steel and a voice coil, and the magnetic steel mainly includes a stator core 1 and a permanent magnet 2. The voice coil mainly includes a coil 3 and a voice coil frame 4. The voice coil frame is installed on the bottom component 5 by bolts, and the stator core of the magnetic steel is installed on the top component 8 by bolts. The low-frequency dynamic force sensor mainly includes an elastic element 6 and a semiconductor strain gauge 7. One end of the elastic element 6 is connected to the voice coil frame by bolts, and the other end is connected to the magnetic steel permanent magnet by epoxy glue. The voice coil actuator is coaxially connected to the force sensor. The force sensor can measure the dynamic force F exerted on the top component. The elastic element of the force sensor has the characteristics of a spring and damping, and can provide passive vibration isolation for the top plate. The voice coil actuator can actively isolate the top component from vibration. The structure of the low-frequency sensing and actuating integrated device is shown in FIG. Figure 2-3 shown.

[0040] In one embodiment, the main structure of the low-frequency dynamic force sensor is a cylindrical elastic element, and a strain gauge is attached to the surface of the elastic element. As the elastic element is deformed by force, the sensitive grid of the strain gauge also obtains the same deformation, so that its resistance changes accordingly, and this resistance change is proportional to the strain of the elastic element. This resistance change is converted into a voltage change through a bridge measurement circuit, thereby obtaining the magnitude of the strain of the elastic element. Finally, the magnitude of the force applied to the elastic element is calculated by Hooke's law. The structure of the low-frequency dynamic force sensor and the elastic element entity are as follows: Figure 4-5 shown.

[0041] In order to improve the sensitivity of the low-frequency dynamic force sensor, polyurethane material is used as the elastic element of the low-frequency dynamic force sensor, and its elastic modulus is 4.1×10 7 Pa is one thousandth of the elastic modulus of metal. Polyurethane material has higher elasticity and greater damping than metal material, and can effectively provide passive vibration isolation performance. In order to facilitate the pasting of strain gauges, the outer diameter is designed to be 15mm and the height is designed to be 30mm. Elastomers processed by polyurethane materials such as Figure 4 shown.

[0042] Traditional strain sensors mainly use metal strain gauges as measuring elements, which have low sensitivity coefficients, long response times, and cannot perform dynamic measurements. In a preferred embodiment, the low-frequency dynamic force sensor uses a TP-5 semiconductor strain gauge made of single crystal silicon, and the detailed parameters are shown in Table 1. Semiconductor strain gauges are sensitive elements made using the piezoresistive effect of semiconductor single crystal silicon, and have the advantages of small mechanical hysteresis, small size, and low power consumption. Semiconductor strain gauges have better temperature stability and a wider operating temperature range than traditional metal strain gauges, and can work normally in the range of -55-200°C. The response time of semiconductor strain gauges is faster than that of metal strain gauges, and can reflect the strain changes of objects within microseconds. The sensitivity coefficient is high, and its sensitivity coefficient is 50 times that of ordinary metal strain gauges.

[0043] Table 1 Parameters of TP-5 semiconductor strain gauge

[0044]

[0045] The measurement circuit adopts a composite full-bridge connection method, using 8 semiconductor strain gauges symmetrically pasted around the elastic body. This bridge circuit can maximize the sensitivity of the sensor and effectively reduce the strain error caused by eccentric load, and also has a temperature compensation function. Figure 6-7 shown.

[0046] It can be seen from the strain measurement principle that the strain ε of a single strain gauge is 11 The total strain measured using a full-bridge circuit is The relationship between them is:

[0047]

[0048] Among them, ε 11 ,ε 12 ,ε 21 ,ε 22 ,ε 31 ,ε 32 ,ε 41 ,ε 42 They are strain gauge R 11 ,R 12 ,R 21 ,R 22 ,R 31 ,R 32 ,R 41 ,R 42 The strain value; ε T is the strain value corresponding to the temperature; is the measured value of the full bridge; μ is the Poisson's ratio of the elastic material of the low-frequency dynamic force sensor. From formula (1), it can be seen that the strain value ε corresponding to the temperatureT With full bridge measurement Don't care, full bridge measurement value Much larger than the value measured using a single strain gauge 11 Therefore, the measurement value obtained by using the composite full-bridge connection method can effectively improve the sensitivity of the sensor and suppress the influence of ambient temperature.

[0049] The voice coil actuator adopts a cylindrical linear voice coil motor solution, which is mainly composed of two parts: magnet and voice coil. Its structure is as follows Figure 5-7 As shown. The magnetic steel adopts an inner cylindrical magnetic steel structure, which mainly includes a permanent magnet and a stator core. The cylindrical permanent magnet is glued to the magnetic steel slot with epoxy resin glue. It is characterized by axial magnetization, compact and firm structure, which is beneficial to improve the structural strength of the magnetic steel. The permanent magnet adopts high-performance N42SH NiFeBo permanent magnet, which has a high magnetic energy product and is beneficial to improve the power density of the motor. The magnetic steel core is made of magnetic conductive stainless steel, steel grade 2Cr13, which can ensure both magnetic conductivity and structural strength. The structure of the magnetic steel is as shown Figure 8-9 shown.

[0050] The voice coil mainly includes a coil and a voice coil frame. The coil adopts a ring-shaped multi-layer winding, which is wound with high-strength enameled wire QY-2 / 220, and the voice coil frame material is 6061 aluminum alloy. The voice coil is connected to the magnetic steel through a force sensor. The height H of the voice coil part and the gap h between the voice coil and the magnetic steel can be designed according to the vibration isolation requirements, so as to ensure that the movement stroke of the voice coil actuator is h. The structure of the voice coil is as follows Figure 10-11 As shown, the design position of the voice coil actuator is as follows Fig.12 shown.

[0051] The working process of the low-frequency micro-vibration sensor and actuator integrated device is as follows: Fig.13 As shown. When the top component is disturbed by the dynamic force F, the low-frequency dynamic force sensor is deformed by the force, and the force value signal is converted into a voltage and transmitted to the signal conditioner. The signal conditioner outputs the signal to the real-time controller, which can collect the information of the force value F of the low-frequency dynamic force sensor in real time. The real-time controller outputs the control current to the voice coil driver through the calculation of the control algorithm, drives the voice coil actuator to output the control force to control the vibration of the top component, and can achieve the stable state of the top component.

[0052] The present invention also provides an active vibration isolation device, which includes the above-mentioned low-frequency micro-vibration sensor and actuation integrated device, a power supply, a signal conditioner, a real-time controller and a voice coil driver, wherein the power supply is used to provide power for the active vibration isolation device, the signal conditioner is data-connected with the low-frequency micro-vibration sensor and actuation integrated device and the real-time controller, the real-time controller is further electrically connected with the voice coil driver, and the voice coil driver is further electrically connected with the low-frequency micro-vibration sensor and actuation integrated device;

[0053] The working process of the active vibration isolation device is as follows: when the top component is disturbed by the dynamic force F, the low-frequency dynamic force sensor is deformed by the force, and the force value signal is converted into a voltage and transmitted to the signal conditioner; the signal conditioner outputs the signal to the real-time controller to collect the information of the force value F of the low-frequency dynamic force sensor in real time; the real-time controller outputs the control current to the voice coil driver through the calculation of the control algorithm, thereby driving the voice coil actuator to output the control force to control the vibration of the top component, so as to achieve a stable state of the top component, such as Fig.13 shown.

[0054] It should be noted that the above-described embodiments are only preferred embodiments of the present invention. For those skilled in the art, without departing from the principles of the present invention, the present invention may be modified, improved and replaced with equivalents, and these modifications, improvements and equivalent replacements are also considered to fall within the scope of protection of the claims of the present invention.

Claims

1. A low-frequency micro-vibration sensing and actuating integrated device, characterized in that: include: A top component, a voice coil actuator, a low-frequency dynamic force sensor and a bottom component, wherein the voice coil actuator includes a magnet and a voice coil, the voice coil is mounted on the bottom component, the magnet is mounted on the top component, one end of the low-frequency dynamic force sensor is connected to the voice coil, and the other end is connected to the magnet; the low-frequency dynamic force sensor is coaxially connected to the voice coil actuator; the low-frequency dynamic force sensor includes a semiconductor strain gauge as a measuring element, a polyurethane material as an elastic element, and a composite full-bridge circuit as a measuring circuit.

2. The low-frequency micro-vibration sensing and actuating integrated device according to claim 1, characterized in that: The voice coil is mounted on the bottom member via bolts, the magnet is mounted on the top member via bolts, one end of the low-frequency dynamic force sensor is connected to the voice coil via bolts, and the other end is connected to the magnet via epoxy glue.

3. The low-frequency micro-vibration sensing and actuating integrated device according to claim 1, characterized in that: The semiconductor strain gauge is a TP-5 semiconductor strain gauge made of single crystal silicon.

4. The low-frequency micro-vibration sensing and actuating integrated device according to claim 1, characterized in that: The semiconductor strain gauge has an outer diameter of 15 mm and a height of 30 mm.

5. The low-frequency micro-vibration sensing and actuating integrated device according to claim 1, characterized in that: The elastic modulus of the polyurethane material is 4.1×10 7 Pa.

6. The low-frequency micro-vibration sensing and actuating integrated device according to claim 1, characterized in that: The composite full-bridge circuit uses eight semiconductor strain gauges symmetrically pasted around the elastic element.

7. The low-frequency micro-vibration sensing and actuating integrated device according to claim 1, characterized in that: The magnetic steel comprises a permanent magnet and a stator core. The permanent magnet is a neodymium iron boron permanent magnet N42SH, and the stator core is stainless steel with a steel grade of 2Cr13.

8. The low-frequency micro-vibration sensing and actuating integrated device according to claim 1, characterized in that: The voice coil comprises a coil and a voice coil frame. The coil adopts an annular multilayer winding and is wound with high-strength enameled wire QY-2 / 220. The voice coil frame material is 6061 aluminum alloy.

9. The low-frequency micro-vibration sensing and actuating integrated device according to claim 8, characterized in that: The coil is connected to the magnet through the low-frequency dynamic force sensor. The height H of the voice coil and the gap h between the voice coil and the magnet are designed according to vibration isolation requirements, thereby ensuring that the movement stroke of the voice coil actuator is h.

10. An active vibration isolation device, comprising the low-frequency micro-vibration sensor and actuation integrated device according to claim 1, a power supply, a signal conditioner, a real-time controller and a voice coil driver, wherein the power supply is used to provide power for the active vibration isolation device, the signal conditioner is data-connected with the low-frequency micro-vibration sensor and actuation integrated device and the real-time controller, the real-time controller is further electrically connected with the voice coil driver, and the voice coil driver is further electrically connected with the low-frequency micro-vibration sensor and actuation integrated device; The working process of the active vibration isolation device is as follows: when the top component is disturbed by the dynamic force F, the low-frequency dynamic force sensor is deformed by the force, and the force value signal is converted into a voltage and transmitted to the signal conditioner; the signal conditioner outputs the signal to the real-time controller to collect the information of the force value F applied to the low-frequency dynamic force sensor in real time; the real-time controller outputs the control current to the voice coil driver through the calculation of the control algorithm, thereby driving the voice coil actuator to output the control force to control the vibration of the top component, so as to achieve the stable state of the top component.

Images