A weak pressure sensing device based on magnetic bragg grating expansion and contraction

Abstract

The utility model provides a kind of weak pressure sensing device based on magnetic Bragg grating telescopic, comprising: three Bragg gratings, one end of three Bragg gratings is fixedly connected, the other end of three Bragg gratings is respectively along x-axis direction, y-axis direction and z-axis direction layout, the outer surface of three Bragg gratings is respectively coated with pseudo-binary rare earth magnetostrictive alloy;Three excitation coils are respectively wound on the outside of three Bragg gratings, one end of the other two excitation coils is respectively electrically connected with the two ends of one excitation coil, the other end of the other two excitation coils is respectively electrically connected with the power supply end of first power supply to form current loop;Distributed feedback laser is respectively electrically connected with driving board, second power supply and spectrometer;Hall sensing device is electrically connected with second power supply.The beneficial effect is that the utility model can realize weak pressure sensing device structure compact, high sensitivity, cost reduction and have three-dimensional vector force resolution capability.

Description

Technical Field

[0001] This utility model relates to the technical field of pressure sensors, and more specifically, to a weak pressure sensing device based on the stretching of a magneto-Bracket grating. Background Technology

[0002] With the development of advanced manufacturing, robotic tactile sensing, and biomechanics, the demand for high-precision measurement of minute force vectors in three-dimensional space is becoming increasingly urgent. For example, in precision assembly operations, the end effector of a robotic arm needs to sense the three-dimensional force feedback in real time in contact with the workpiece to achieve compliant control and collision protection; in biomedical research, the study of cellular mechanical behavior also requires the precise quantification of three-dimensional microforces.

[0003] Currently, most technical solutions for three-dimensional force measurement are based on integrated multi-dimensional force sensors using traditional electronic sensing principles. These sensors typically employ a method of attaching multiple strain gauges to a rigid force-measuring structure, calculating the three-dimensional force by detecting the resistance changes of each strain gauge. However, this approach has inherent bottlenecks: firstly, its complex structure and difficulties in manufacturing and calibration lead to high costs and limitations in miniaturization; secondly, its electrical signal-based sensing mechanism restricts its application in harsh industrial environments with strong electromagnetic interference, flammable and explosive materials, and the signal is susceptible to noise, resulting in insufficient reliability.

[0004] To overcome electromagnetic interference, optical sensing technology, particularly fiber Bragg grating (FBG) sensors, has been introduced into the field of force sensing due to its inherent safety, resistance to electromagnetic interference, and corrosion resistance. However, most existing FBG three-dimensional force sensing schemes employ a method of deploying multiple independent FBGs at different locations within the elastic body structure. This "spatially distributed" layout has significant drawbacks: firstly, the strain sensed by each FBG is coupled, making the decoupling algorithm extremely complex, and the calculation accuracy heavily dependent on the accuracy of the elastic body model; secondly, each FBG typically requires an independent optical interrogation unit (such as a laser and demodulator) or relies on a complex wavelength division / space division multiplexing system, resulting in a large, complex, and costly overall sensing system.

[0005] Therefore, there is an urgent need in this field for a weak pressure sensing device that has three-dimensional vector force resolution capability, compact structure, high sensitivity, and significantly reduced cost. Utility Model Content

[0006] The technical problem to be solved by this utility model is how to achieve a compact structure, high sensitivity, reduced cost, and three-dimensional vector force resolution capability for a weak pressure sensing device. In order to overcome the defects of the above-mentioned prior art (or related technology), this utility model provides a weak pressure sensing device based on magnetostrictive Bragg grating expansion.

[0007] This utility model provides a weak pressure sensing device based on magneto-Brablin grating expansion, comprising:

[0008] Three Bragg gratings are provided, with one end of each grating fixedly connected and the other ends of each grating arranged along the x-axis, y-axis, and z-axis directions, respectively. The outer surfaces of each grating are coated with a pseudo-binary rare-earth magnetostrictive alloy.

[0009] Three excitation coils are respectively wound around the outside of the three Bragg gratings. The two ends of one of the excitation coils are electrically connected to one end of the other two excitation coils, and the other ends of the other two excitation coils are electrically connected to the power supply terminal of the first power supply device to form a current loop.

[0010] A distributed feedback laser is electrically connected to a driver board, a second power supply device, and a spectrometer. The distributed feedback laser emits laser light to irradiate any of the Bragg gratings to generate a wavelength shift signal within the spectrometer.

[0011] A Hall effect sensor is electrically connected to the second power supply device. The Hall effect sensor detects and displays the magnetic field strength value.

[0012] Compared with existing technologies, the weak pressure sensing device based on magneto-Brablin grating expansion proposed in this application has the following advantages:

[0013] In this application, three Bragg gratings are orthogonally arranged along the X, Y, and Z axes and fixed at one end to form a spatial force sensing origin. This structure can directly and independently sense the force components in the three directions, thereby calculating the magnitude and direction of the spatial force, solving the problem that traditional one-dimensional sensors cannot measure multi-dimensional forces. The three Bragg gratings share the same fixed end, forming a natural three-dimensional force-sensitive structure, making the sensing device structure very compact. Each Bragg grating is individually coated with a pseudo-binary rare-earth magnetostrictive alloy, realizing the independence and specialization of the magneto-force-optical conversion path, avoiding signal crosstalk, and ensuring high measurement sensitivity in each direction. Connecting the three excitation coils in series in a specific way means that only one first power supply device is needed to simultaneously excite the excitation coils in the three directions, greatly simplifying the drive circuit and control system and reducing hardware costs.

[0014] In one possible implementation, the center wavelength of the three Bragg gratings is 1550 ± 0.05 nm.

[0015] In one possible implementation, the distributed feedback laser has a center wavelength of 1550 nm and a power of 7 mW.

[0016] Compared with existing technologies, the above technical solution can accurately match the center wavelength of the distributed feedback laser with the center wavelength of the Bragg grating, which can excite the strongest reflection spectrum of the Bragg grating and ensure the highest wavelength detection sensitivity. At the same time, the power is limited to 7mW, which provides a sufficiently strong optical signal to ensure the signal-to-noise ratio, while avoiding nonlinear effects or grating damage that may be caused by excessive power.

[0017] In one possible implementation, the three excitation coils each have an outer diameter of 40 mm and a length of 23.6 mm, and each excitation coil is made by winding 1400 turns of enameled copper wire with a diameter of 0.35 mm.

[0018] Compared with existing technologies, the above technical solution can determine the electromagnetic conversion efficiency and magnetic field uniformity of the excitation coil by limiting the parameters of the coil outer diameter, coil length, and copper wire diameter. This ensures that a sufficiently strong and stable magnetic field can be generated under a given current to effectively drive the magnetostrictive material, thereby guaranteeing the sensitivity and response consistency of the sensing device.

[0019] In one possible implementation, the pseudobinary rare-earth magnetostrictive alloy is obtained by polymerizing Tb0.3Dy0.7Fe2 alloy powder.

[0020] Compared with existing technologies, the above-mentioned technical solution can utilize the extremely high magnetostriction coefficient and good linearity of Tb0.3Dy0.7Fe2 alloy powder at room temperature to significantly improve the sensitivity of the sensing device, and make the relationship between wavelength shift and magnetic field and pressure more linear, reducing the complexity of calibration and calculation, while also having good temperature stability.

[0021] In one possible implementation, the three Bragg gratings are respectively engaged and fixed in a fixing groove.

[0022] Compared with existing technologies, the above technical solution can lock and fix the Bragg grating through the fixing groove structure, ensuring good mechanical stability. It can effectively prevent the Bragg grating from sliding or twisting under force, and ensure that strain can be accurately transmitted and measured.

[0023] In one possible implementation, the Hall sensing device includes a Hall element and an OLED display electrically connected to the Hall element.

[0024] Compared with existing technologies, the above technical solution can detect magnetic fields through Hall elements and display numerical values ​​on an OLED display screen, which greatly facilitates user operation and status monitoring. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structural principle of this utility model;

[0026] Figure 2 This is a schematic diagram of the connection principle of the distributed feedback laser of this utility model;

[0027] Figure 3 This is a schematic diagram of the structure of the Bragg grating of this utility model;

[0028] Figure 4 This is a schematic diagram showing the position of the excitation coil of this utility model;

[0029] Figure 5 This is a schematic diagram of the Hall sensor device of this utility model; Attached image description:

[0031] 1. Bragg grating; 2. Excitation coil; 3. First power supply device; 4. Distributed feedback laser; 5. Driver board; 6. Second power supply device; 7. Spectrometer; 8. Hall effect sensor. Detailed Implementation

[0032] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0033] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0034] See Figures 1-5 This application discloses a weak pressure sensing device based on magnetostrictive Bragg grating expansion, mainly including a Bragg grating 1, an excitation coil 2, a first power supply device 3, a distributed feedback laser 4, a driver board 5, a second power supply device 6, a spectrometer 7, and a Hall effect sensor 8. In terms of connection, this embodiment uses three Bragg gratings 1 and three excitation coils 2. One end of each of the three Bragg gratings 1 is fixedly connected, and the other ends are respectively arranged along the x-axis, y-axis, and z-axis directions. The outer surfaces of the three Bragg gratings 1 are respectively coated with a pseudo-binary rare-earth magnetostrictive alloy. The three excitation coils... 2 are respectively wound around the outside of three Bragg gratings 1. The two ends of one excitation coil 2 are electrically connected to one end of the other two excitation coils 2 respectively. The other ends of the other two excitation coils 2 are electrically connected to the power supply end of the first power supply device 3 to form a current loop. The distributed feedback laser 4 is electrically connected to the drive board 5, the second power supply device 6 and the spectrometer 7 respectively. The Hall sensor 8 is electrically connected to the second power supply device 6. In terms of functional implementation, the distributed feedback laser 4 emits a laser to irradiate any Bragg grating 1 to generate a wavelength shift signal in the spectrometer 7. The Hall sensor 8 detects and displays the magnetic field strength value.

[0035] In this embodiment, a pseudo-binary rare-earth magnetostrictive alloy, Terfenol-D, is used to replace traditional magnetic powder. Its superior magnetostrictive properties are more than 10 times that of ordinary magnetic powder, which greatly improves the sensitivity of the sensing device. At the same time, it has better linearity and temperature stability, breaking through the performance limitations of traditional magnetic powder materials.

[0036] In this embodiment, the weak pressure sensing device comprises three parts: a light source, a sensing component, and a result display component. The light source includes a distributed feedback laser 4, a driver board 5, and a second power supply 6. The second power supply 6 can be an Arduino board. The distributed feedback laser 4 has a center wavelength of 1550nm and a power of 7mW. The driver board 5 is the core control unit, ensuring the safe and controllable laser output of the distributed feedback laser 4 through precise current regulation. The second power supply 6 provides the driver board 5 with a 5V power supply, and its other end is connected to an ammeter for controlling the opening and closing of the entire sensing device. The sensing component includes an excitation coil 2, a Bragg grating 1, a pseudo-binary rare-earth magnetostrictive alloy, and a Hall effect sensor 8. The excitation coil 2 is made of high-strength enameled copper wire, using 1400 turns of 0.35 mm diameter copper wire to form an outer diameter of 40 mm and a length of 23.6 mm. The coil is made of three Bragg gratings (1) and communication-grade single-mode fiber. Its core parameters have been rigorously selected, and its center wavelength is 1550±0.05nm, which is precisely matched with the output wavelength of the distributed feedback laser (4). The pseudo-binary rare-earth magnetostrictive alloy is used as the key magnetostrictive conversion medium. The alloy powder with the composition Tb0.3Dy0.7Fe2 is selected, which has the best magnetostrictive effect. When the pseudo-binary rare-earth magnetostrictive alloy is subjected to a magnetic field, it drives the Bragg grating (1) to expand and contract, causing the Bragg grating (1) to produce strain. The magnetic field strength value is displayed in real time by the Hall sensor (8). The result display part is the data acquisition and analysis terminal, which uses a Yokogawa AQ6370B spectrometer, which can accurately capture wavelength shift signals with high resolution.

[0037] In this embodiment, a novel weak pressure sensing device was developed based on the principle of magnetostrictive fiber Bragg grating expansion and contraction, achieving high-precision measurement of minute forces. In this embodiment, pseudo-binary rare-earth magnetostrictive alloy Terfenol-D is deposited on the surface of Bragg grating 1 with a center wavelength of 1550nm. The magnetostrictive Terfenol-D expansion and contraction causes the Bragg grating 1 to be subjected to weak pressure and generate strain. Finally, the weak pressure is accurately measured by the change in the center wavelength of the light. At the same time, a three-dimensional structure with three Bragg gratings distributed along the x, y, and z directions was designed, which can realize the measurement and visualization of three-dimensional forces. By linking magnetism, force, and light, a high-sensitivity force sensing system with multi-physics coupling is established, which has better linearity and stability. It solves the problem of force measurement in certain scenarios by traditional sensors and has important application value in many key fields such as biomedicine.

[0038] In this embodiment, the core principle of the weak pressure sensing device is based on the magnetostrictive properties of Terfenol-D. Changes in the magnetic field in the environment are used to excite the Terfenol-D to produce a magnetostrictive effect, causing a change in its length and thus mechanical strain. Under the action of mechanical strain, the Λ of the Bragg grating 1 changes, resulting in a change of Δφ at the center wavelength of reflection in the Bragg grating 1. By monitoring the change in Δφ, accurate detection of the magnetic field strength in the environment can be achieved. Simultaneously, based on the correspondence between mechanical strain and magnetic force, a quantitative relationship can be established between the wavelength shift signal, the magnetic field strength value, and the weak pressure.

[0039] In the description of this application, the references to terms such as "an embodiment," "some embodiments," "in this embodiment," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0040] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A weak pressure sensing device based on magneto-Brablin grating expansion, characterized in that, include: Three Bragg gratings (1) are fixedly connected at one end, and the other ends of the three Bragg gratings (1) are respectively arranged along the x-axis, y-axis and z-axis directions. The outer surfaces of the three Bragg gratings (1) are respectively coated with pseudo-binary rare earth magnetostrictive alloy. Three excitation coils (2) are respectively wound around the outside of the three Bragg gratings (1). The two ends of one of the excitation coils (2) are electrically connected to one end of the other two excitation coils (2), and the other ends of the other two excitation coils (2) are electrically connected to the power supply end of the first power supply device (3) to form a current loop. A distributed feedback laser (4) is electrically connected to a driver board (5), a second power supply device (6) and a spectrometer (7) respectively. The distributed feedback laser (4) emits laser light to irradiate any of the Bragg gratings (1) to generate a wavelength shift signal in the spectrometer (7). A Hall sensor (8) is electrically connected to the second power supply device (6). The Hall sensor (8) detects and displays the magnetic field strength value.

2. The weak pressure sensing device according to claim 1, characterized in that, The center wavelength of the three Bragg gratings (1) is 1550 ± 0.05 nm.

3. The weak pressure sensing device according to claim 2, characterized in that, The center wavelength of the distributed feedback laser (4) is 1550nm and the power is 7mW.

4. The weak pressure sensing device according to claim 1, characterized in that, The outer diameter of the three excitation coils (2) is 40 mm and the length is 23.6 mm. The three excitation coils (2) are all made by winding 1400 turns of enameled copper wire with a diameter of 0.35 mm.

5. The weak pressure sensing device according to claim 1, characterized in that, The pseudo-binary rare earth magnetostrictive alloy is obtained by polymerizing Tb0.3Dy0.7Fe2 alloy powder.

6. The weak pressure sensing device according to claim 1, characterized in that, The three Bragg gratings (1) are respectively engaged and fixed in a fixed groove.

7. The weak pressure sensing device according to claim 1, characterized in that, The Hall sensor (8) includes a Hall element and an OLED display screen electrically connected to the Hall element.

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