A tri-giant magnetic effect based inductive sensor, preparation method and application thereof
By combining a planar spiral structure of amorphous filaments and PDMS foam of neodymium iron boron microparticles in the sensor, a double-layer inductive sensor is formed, which solves the problems of low sensor sensitivity and insufficient flexibility, and realizes efficient hand rehabilitation monitoring.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG UNIV
- Filing Date
- 2024-03-14
- Publication Date
- 2026-07-21
AI Technical Summary
Existing inductive sensors have low sensitivity, complex structure, and lack of flexibility, making it difficult to effectively monitor the hand rehabilitation effects of stroke patients.
The inductive sensor employing the triple giant magnetic effect uses amorphous wire wound in a planar spiral in silicone rubber, with neodymium iron boron microparticles embedded in the upper layer of PDMS foam, combined with LC resonance, to form a double-layer structure, thereby improving magnetic field sensitivity and stress sensing capability.
It achieves a wide stress sensing range of up to 1000 kPa, robustness of over 15,000 cycles, fast response time of 40 milliseconds, sensitivity of 6.6%/kPa, and linearity of 0.99717, enabling dynamic monitoring of hand rehabilitation effects.
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Figure CN118024610B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of flexible electronic device design, specifically relating to an inductive sensor based on the triple giant magnetometry effect for hand rehabilitation monitoring, its preparation method, and its application. Background Technology
[0002] Stroke is one of the most common and serious disabling diseases worldwide, with 70%-85% of first-time strokes accompanied by hemiplegia. Spastic hemiplegia is characterized by a significant increase in muscle tone, resulting in flexion of the upper limb, extension of the lower limb, flexion and closure of the fingers, and stiffness and resistance in passively extended hands. Currently, most post-stroke care still relies on rehabilitation interventions. However, due to the lengthy rehabilitation process and the lack of assessment of rehabilitation effectiveness, patients are prone to losing confidence and giving up halfway.
[0003] In recent years, flexible electronics technology has attracted much attention due to its wide application in fields such as human physiological signal measurement, flexible robots, and wearable devices. Inductance is one of the fundamental parameters of electricity, but due to the lack of corresponding force-responsive materials, it is rarely used as a response signal for flexible electronic devices. Current research on inductive sensors mostly focuses on the structural design of conductive coils, which suffers from drawbacks such as low sensitivity and complex structures, limiting its further development. Since K. Mohri et al. of Nagoya University in Japan discovered the giant magnetoinductance effect (later extended to the giant magnetoresistance (GMI) effect) in CoFeB soft magnetic amorphous wires in 1992, its advantages of high magnetic field sensitivity, small size, fast response speed, and low power consumption have made it a promising candidate for application in weak magnetic field detection. In 1995, M. Vazquez et al. discovered that the dispersion characteristics of GMI can be strongly affected by applied stress; this stress impedance (GSI) effect can be applied to structural health monitoring, stress sensors, and other fields. However, amorphous wires are rarely used in the development of flexible sensor devices due to their rigidity.
[0004] Embedding amorphous wires into a flexible substrate (such as silicone rubber PDMS) is the most direct way to make this type of sensing element flexible. However, since the impedance of amorphous wires initially increases and then decreases under pressure, this non-monotonicity is detrimental to the interpretation of sensing signals. By constructing a spiral structure to convert the pressure acting on the PDMS into tensile stress on the amorphous wire, the monotonicity problem of the output signal is solved, and this spiral structure can significantly improve its magnetic field sensitivity. Inspired by the giant magnetoelasticity (GME) effect discovered by Chen Jun et al. in soft magnets, this invention proposes a double-layer flexible pressure sensor, with the lower layer being an amorphous wire embedded with a spiral structure and the upper layer being a PDMS foam containing neodymium iron boron particles. Through the coupling of the triple giant magnetoelastic effect, the sensor containing 8 wt% mass fraction exhibits a wide stress sensing range of up to 1000 kPa, excellent robustness exceeding 15,000 cycles, and a fast response and recovery time of 40 milliseconds. Furthermore, by artificially constructing an LC resonance, a 680pF sensor connected in series exhibits a sensitivity of 6.6% / kPa and a linearity of 0.99717 within a stress range up to 100kPa. Integrating the sensor with a series capacitor and a commercial finger separator allows for dynamic monitoring of hand rehabilitation effects. In addition, this invention not only provides a research paradigm that integrates the conductivity, soft magnetic properties, GMI effect, and GSI effect of amorphous filaments, but also endows the invention with the ability to detect static pressure using the GME effect. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an inductive sensor based on the triple giant magnetostatic effect, its fabrication method, and its applications. This sensor exhibits a wide stress sensing range up to 1000 kPa, excellent robustness exceeding 15,000 cycles, and a fast response and recovery time of 40 milliseconds. Furthermore, when connected in series with a 680 pF standard capacitor, it demonstrates a sensitivity of 6.6% / kPa and a linearity of 0.99717 within a stress range up to 100 kPa. Integrating the sensor with the capacitor in series with a commercial finger separator allows for dynamic monitoring of hand rehabilitation effects and offers room for further optimization.
[0006] The specific technical solution adopted in this invention is as follows:
[0007] In a first aspect, the present invention provides a method for fabricating an inductive sensor based on the triple giant magnetostatic effect, as detailed below:
[0008] Amorphous wires are wound in a planar spiral manner and cured after being injected with silicone rubber to obtain a lower structure. A silicone rubber foam containing neodymium iron boron microparticles is prepared on the lower structure using a sugar template method to serve as the upper structure, resulting in an inductive sensor with a double-layer structure based on the triple giant magnetometry effect.
[0009] Preferably, the method for preparing the lower layer structure is as follows:
[0010] Several pillars are detachably embedded in the mold, and amorphous wires are wound on the pillars in a planar spiral manner. Then, the frame is placed above the mold, and silicone rubber prepolymer and curing agent after vacuum degassing are injected into the frame. After curing at 150°C for 15 minutes, the lower structure is obtained.
[0011] Furthermore, the mold, support, and frame are all made of stainless steel.
[0012] Preferably, the amorphous wire is composed of Co. 68.7 Fe4Si 11 B 13 Ni1Mo 2.3 It has a diameter of 30μm and a winding number of 3.5 turns.
[0013] Preferably, the winding method includes all round mosquito coil types, square mosquito coil types, and annular and planar spiral structures that can generate inductive effects.
[0014] Preferably, the method for preparing the upper structure is as follows:
[0015] Remove several pillars from the mold, pour granulated sugar into the frame and flatten it. Then pour the mixture of neodymium iron boron powder, silicone rubber prepolymer and curing agent into the frame and smooth the surface. Next, cure at 150°C for 15 minutes. After demolding, soak the product in water to dissolve the granulated sugar and form a sponge structure to obtain the upper structure.
[0016] Preferably, the NdFeB microparticles have a particle size of 5 μm, and the white sugar in the sugar template method has a particle size of 300-600 μm.
[0017] In a second aspect, the present invention provides an inductive sensor based on the triple giant magnetotropic effect obtained by any of the preparation methods described in the first aspect.
[0018] Thirdly, the present invention provides an application of an inductive sensor based on the triple giant magnetodynamic effect, as described in the second aspect, in an intelligent finger separator for dynamically monitoring the hand rehabilitation effect of hemiplegic patients.
[0019] Preferably, the intelligent finger-splitter is obtained by integrating an inductive sensor connected in series with a standard capacitor onto the finger-splitter.
[0020] Compared with the prior art, the present invention has the following advantages:
[0021] (1) Under the limitation of the brittle characteristics of amorphous wires themselves, the present invention adopts a strategy of combining soft and hard to extend amorphous wires to the field of flexible sensing.
[0022] (2) The present invention utilizes a planar spiral structure, which not only solves the problem of the non-monotonicity of the impedance signal of the amorphous wire under pressure, but also improves the magnetic sensitivity of the amorphous wire.
[0023] (3) This invention improves stress sensitivity by compositing PDMS foam containing NdFeB magnetic particles and tuning the magnetic field acting on the plane of the amorphous wire to be approximately near the anisotropic field; at the same time, it couples the decrease in magnetization under pressure with the decrease in impedance caused by the GMI effect, further enhancing its pressure sensitivity.
[0024] (4) Thanks to the soft magnetic properties, rigidity and high mechanical strength of amorphous wires, the sensor prepared by this method has a wide stress sensing range of up to 1000 kPa, excellent robustness of more than 15,000 cycles and fast response and recovery time of 40 milliseconds.
[0025] (5) The present invention further improves the sensing sensitivity of the device by artificially constructing LC resonance, and the sensor has a sensitivity of 6.6% / kPa and a linearity of 0.99717 in the range of 0-100kPa.
[0026] (6) This invention not only provides a research paradigm for integrating the conductivity, soft magnetic properties, mechanical properties, GMI effect and GSI effect of amorphous wires, but also endows the GME effect with the ability to detect static pressure. Attached Figure Description
[0027] Figure 1 This is a schematic diagram of the sensor fabrication process in Example 1;
[0028] Figure 2 Pressure sensitivity curves of PDMS with embedded linear and spiral amorphous wires in Comparative Example 1 and Comparative Example 2;
[0029] Figure 3 Sensitivity curves of PDMS foams with different mass fractions of NdFeB incorporated into spiral amorphous wires in Examples 1, 3, and 4.
[0030] Figure 4 The sensor response and reply curves are from Example 1;
[0031] Figure 5 This is a graph showing the signal changes after 15,000 cyclic loading cycles in Example 1;
[0032] Figure 6 The sensitivity curve of the pressure sensor with a standard capacitor connected in series in Example 1;
[0033] Figure 7 A schematic diagram of the finger plate of the pressure sensor designed for integration in Example 1;
[0034] Figure 8 This is a graph showing the changes in sensor signals corresponding to the changes in hand muscle strength in a simulated hemiplegic patient during the rehabilitation process, as described in Example 1. Detailed Implementation
[0035] The present invention will be further described and illustrated below with reference to the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly, provided that there is no mutual conflict.
[0036] This invention provides an inductive sensor based on the triple giant magnetostatic effect. The inductive sensor has a double-layer structure: the lower layer is silicone rubber (PDMS) with embedded helical amorphous filaments, and the upper layer is PDMS foam doped with neodymium iron boron (NdFeB) particles. The specific fabrication method of this inductive sensor is as follows:
[0037] S1: Amorphous wires are wound in a planar spiral manner and then cured after being injected with silicone rubber to obtain the lower layer structure.
[0038] In a preferred embodiment of the present invention, the lower structure is formed by winding embedded pillars in a stainless steel mold to achieve an amorphous filament configuration, and the structure is maintained by PDMS (prepared by silicone rubber prepolymer and curing agent). The specific preparation method is as follows:
[0039] Multiple pillars are detachably embedded in the mold. Amorphous wires are wound on the pillars in a planar spiral manner. Then, the frame is placed above the mold, and 0.2 ml of silicone rubber prepolymer and curing agent (mass ratio of 10:1, purchased from Dow Corning, USA) after vacuum degassing is injected into the frame. After curing in an oven at 150°C for 15 minutes, the lower structure is obtained.
[0040] In practical applications, the mold, support, and frame are all made of stainless steel. The winding methods include all types of coiled mosquito coils, such as round, square, and toroidal or near-planar spiral structures, that can generate inductive effects. The amorphous filaments can be made from Co... 68.7 Fe4Si 11 B 13 Ni1Mo 2.3 It has a diameter of approximately 30 μm and is wound with 3.5 turns.
[0041] S2: A silicone rubber foam containing neodymium iron boron microparticles is prepared on the lower structure obtained in step S1 using the sugar template method to serve as the upper structure, thereby obtaining an inductive sensor with a double-layer structure based on the triple giant magnetism effect.
[0042] As a preferred embodiment of the present invention, the preparation method of the upper structure is as follows:
[0043] Remove the multiple support pillars from the mold, pour 0.4g of white sugar into the frame and flatten it. Then pour a mixture of 0.4ml of neodymium iron boron powder, silicone rubber prepolymer and curing agent into the frame and smooth the surface with a glass scraper. Then cure it again at 150℃ for 15min. After demolding, soak the product in distilled water to dissolve the white sugar and form a sponge structure to obtain the upper structure.
[0044] Specifically, the preparation method of the mixture of NdFeB powder, silicone rubber prepolymer, and curing agent is as follows:
[0045] Neodymium iron boron (NdFeB) powder was mixed with PDMS prepolymer and rapidly stirred with a high-speed homogenizer to disperse it evenly. The curing agent was then mixed with the product and vacuum degassed to obtain a mixture of the three.
[0046] In practical applications, the particle size of neodymium iron boron microparticles is approximately 5 μm, while the particle size of granulated sugar in the sugar template method is approximately 300-600 μm. The high-speed homogenizer operates at a speed of 6 kr / min for 10 min.
[0047] After the sensor is fabricated, it can be magnetized in the horizontal direction (i.e., parallel to the horizontal cross-section of the sensor). Then, an LC resonance is artificially constructed by connecting a standard capacitor in series to achieve a significant improvement in sensing performance. Finally, the inductive sensor with the standard capacitor in series is integrated into a commercial finger-split board to achieve dynamic monitoring of the hand rehabilitation effect of hemiplegic patients.
[0048] Specifically, a magnetic pulse can be applied to the sensor using a pulse magnetizer to magnetize it; the magnitude of the pulse magnetic field is approximately 4T. After removing the exposed amorphous glass cladding layer and confirming conductivity, the sensor is connected in series with a standard capacitor. Its sensing performance is then tested using an LCR meter and a universal testing machine. The standard capacitor has a capacitance of 680pF, the LCR meter test conditions are 1mV voltage and 2MHz frequency, and the universal testing machine loading rate is 5μm / s.
[0049] The sensing mechanism of the sensor in this invention couples the GMI and GSI effects of the amorphous filament with the GME effect of the soft magnet (i.e., the upper structure), namely the triple giant magnetism effect. The sensing signal of the sensor with a standard capacitor in series manifests as a change in reactance, but this change is attributed to the change in inductance of the amorphous filament.
[0050] Example 1
[0051] like Figure 1 As shown, this embodiment provides an inductive sensor based on the triple giant magnetostatic effect, and the specific fabrication method is as follows:
[0052] S1: First, assemble the stainless steel mold and place Co... 68.7Fe4Si 11 B 13 Ni1Mo 2.3 Glass-coated amorphous wires were wound around the pillars of the mold, with 3.5 turns. A stainless steel frame was placed above the mold, and 0.2 ml of vacuum-de-bubbled PDMS prepolymer and curing agent (mass ratio 10:1) were injected. The mold was then placed in a 150°C oven and cured for 15 minutes before being removed.
[0053] S2: Mix neodymium iron boron (NdFeB) powder (5μm particle size) with PDMS prepolymer and stir at 6.0kr / min for 10min using a high-speed homogenizer to ensure uniform dispersion. Mix the curing agent with the mixture and then degas under vacuum. Remove the support pillars from the mold, pour 0.4g of granulated sugar into the square and flatten it. Pour 0.4ml of the above mixture into the sugar template, smooth the surface with a glass scraper, and then perform a second curing at 150℃ for 15 minutes.
[0054] S3: After demolding, the material was soaked in distilled water to dissolve the sugar and form a sponge structure. Then, a magnetic pulse of approximately 4T was applied in the in-plane axial direction using a pulse magnetizer to magnetize the block. After grinding away the exposed amorphous glass cladding layer and confirming conductivity, it was connected in series with a 680pF standard capacitor. Its sensing performance was tested using an LCR meter and a universal testing machine. The LCR meter's test voltage was 1mV and the frequency was 2MHz, while the universal testing machine's loading rate was 5μm / s. Finally, the pressure sensor connected in series with the standard capacitor was integrated into a commercially available finger-split board, and its reactance changes under different muscle strengths were tested to simulate changes in hand strength control during the rehabilitation of hemiplegic patients.
[0055] In this embodiment, the mass fraction of neodymium iron boron (NdFeB) is 8 wt%.
[0056] like Figure 3 As shown, the sensor exhibits the highest sensitivity when the NdFeB mass fraction is 8 wt%.
[0057] like Figure 4 As shown, the response time and reply time of this sensor are both 40ms.
[0058] like Figure 5 As shown, the sensor exhibits a small signal offset after 15,000 cyclic loading cycles.
[0059] like Figure 6 As shown, after connecting a 680pF standard capacitor in series, the sensitivity of the sensor is significantly improved to 6.6% / kPa in the range of 0-100kPa, and the linearity reaches 0.99717.
[0060] like Figure 7The diagram shown is a schematic of an intelligent indexing board for a sensor that integrates a series standard capacitor.
[0061] like Figure 8 As shown in the figure, the sensor signal changes during the hand rehabilitation process of a stroke hemiplegic patient are simulated. This sensor array has the ability to dynamically monitor and evaluate the hand rehabilitation effect of hemiplegic patients.
[0062] Comparative Example 1
[0063] The differences between this comparative example and Example 1 are as follows: In step S1, the amorphous wire was not wound; in step S2, the upper layer of the sensor is composed of pure PDMS; and in step S3, magnetization and series capacitance were not performed, and the sensor was not integrated onto the finger-mounted board. Other fabrication steps are the same as in Example 1, as detailed below:
[0064] S1: First, assemble the stainless steel mold and place Co... 68.7 Fe4Si 11 B 13 Ni1Mo 2.3 The glass-coated amorphous wire is placed directly in the center; a stainless steel frame is placed above the mold, and 0.2 ml of vacuum-de-bubbled PDMS prepolymer and curing agent (mass ratio 10:1) is injected. The mold is then placed in a 150℃ oven and cured for 15 minutes before being removed.
[0065] S2: Remove the support pillars from the mold, and inject 0.4ml of vacuum-degassed PDMS prepolymer and curing agent (mass ratio 10:1) onto the first-cured block. Smooth the surface with a glass scraper. Then, cure for a second time at 150℃ for 15 minutes.
[0066] S3: After grinding away the glass cladding layer of the exposed amorphous wire on the outside and confirming its conductivity, test its sensing performance using an LCR meter and a universal testing machine. The LCR meter's test voltage is 1mV and the frequency is 2MHz, while the universal testing machine's loading rate is 5μm / s.
[0067] like Figure 2 As shown, the sensing signal of a linear amorphous wire embedded in a PDMS matrix exhibits a trend of first increasing and then decreasing with increasing applied pressure.
[0068] Comparative Example 2
[0069] The difference between this comparative example and Example 1 is that in step S2, the upper layer of the sensor is composed of pure PDMS; and in step S3, magnetization and series capacitance are not performed, nor is it integrated onto the finger-mounted board. The other fabrication steps are the same as in Example 1, as detailed below:
[0070] S1: First, assemble the stainless steel mold and place Co... 68.7 Fe4Si 11 B13 Ni1Mo 2.3 Glass-coated amorphous wires were wound around the pillars of the mold, with 3.5 turns. A stainless steel frame was placed above the mold, and 0.2 ml of vacuum-de-bubbled PDMS prepolymer and curing agent (mass ratio 10:1) were injected. The mold was then placed in a 150°C oven and cured for 15 minutes before being removed.
[0071] S2: Remove the support pillars from the mold, and inject 0.4ml of vacuum-degassed PDMS prepolymer and curing agent (mass ratio 10:1) onto the first-cured block. Smooth the surface with a glass scraper. Then, cure for a second time at 150℃ for 15 minutes.
[0072] S3: After grinding away the glass cladding layer of the exposed amorphous wire on the outside and confirming its conductivity, test its sensing performance using an LCR meter and a universal testing machine. The LCR meter's test voltage is 1mV and the frequency is 2MHz, while the universal testing machine's loading rate is 5μm / s.
[0073] like Figure 2 As shown, the sensing signal of the spiral amorphous wire embedded in the PDMS matrix decreases monotonically with the increase of applied pressure, which is beneficial for the resolution of the sensing signal.
[0074] Comparative Example 3
[0075] The difference between this comparative example and Example 1 is that in step S2, the upper layer of the sensor is composed of PDMS foam doped with NdFeB particles of varying mass fractions; and in step S3, no capacitor is connected in series and integrated onto the finger plate. Other preparation steps are the same as in Example 1, as detailed below:
[0076] S1: First, assemble the stainless steel mold and place Co... 68.7 Fe4Si 11 B 13 Ni1Mo 2.3 Glass-coated amorphous wires were wound around the pillars of the mold, with 3.5 turns. A stainless steel frame was placed above the mold, and 0.2 ml of vacuum-de-bubbled PDMS prepolymer and curing agent (mass ratio 10:1) were injected. The mold was then placed in a 150°C oven and cured for 15 minutes before being removed.
[0077] S2: Mix neodymium iron boron (NdFeB) powder (5μm particle size) with PDMS prepolymer and stir at 6.0kr / min for 10min using a high-speed homogenizer to ensure uniform dispersion. Mix the curing agent with the mixture and then degas under vacuum. Remove the support pillars from the mold, pour 0.4g of granulated sugar into the square and flatten it. Pour 0.4ml of the above mixture into the sugar template and smooth the surface with a glass scraper. Then, perform a second curing at 150℃ for 15 minutes.
[0078] S3: After demolding, the block was soaked in distilled water to dissolve the sugar and form a sponge structure. A magnetic pulse of approximately 4T was applied in the in-plane axial direction using a pulse magnetizer to magnetize the block. After grinding away the exposed amorphous glass cladding layer and confirming conductivity, its sensing performance was tested using an LCR meter and a universal testing machine. The LCR meter's test voltage was 1mV, the frequency was 2MHz, and the universal testing machine's loading rate was 5μm / s.
[0079] In this comparative example, the mass fraction of neodymium iron boron (NdFeB) was 4 wt%.
[0080] like Figure 3 As shown, the sensor doped with 4 wt% NdFeB particles has lower sensitivity than the sensor doped with 8 wt%. This is because the giant magnetoelastic effect is not obvious with low doping. However, since the modulus of the upper foam is lower than that of the lower bulk, under the same stress, the upper foam deforms more than the amorphous filaments.
[0081] Comparative Example 4
[0082] The difference between this comparative example and Example 1 is that in step S2, the upper layer of the sensor is composed of PDMS foam doped with NdFeB particles of varying mass fractions; and in step S3, no capacitor is connected in series and integrated onto the finger plate. Other preparation steps are the same as in Example 1, as detailed below:
[0083] S1: First, assemble the stainless steel mold and place Co... 68.7 Fe4Si 11 B 13 Ni1Mo 2.3 Glass-coated amorphous wires were wound around the pillars of the mold, with 3.5 turns. A stainless steel frame was placed above the mold, and 0.2 ml of vacuum-de-bubbled PDMS prepolymer and curing agent (mass ratio 10:1) were injected. The mold was then placed in a 150°C oven and cured for 15 minutes before being removed.
[0084] S2: Mix neodymium iron boron (NdFeB) powder (5μm particle size) with PDMS prepolymer and stir at 6.0kr / min for 10min using a high-speed homogenizer to ensure uniform dispersion. Mix the curing agent with the mixture and then degas under vacuum. Remove the support pillars from the mold, pour 0.4g of granulated sugar into the square and flatten it. Pour 0.4ml of the above mixture into the sugar template and smooth the surface with a glass scraper. Then, perform a second curing at 150℃ for 15 minutes.
[0085] S3: After demolding, the block was soaked in distilled water to dissolve the sugar and form a sponge structure. A magnetic pulse of approximately 4T was applied in the in-plane axial direction using a pulse magnetizer to magnetize the block. After grinding away the exposed amorphous glass cladding layer and confirming conductivity, its sensing performance was tested using an LCR meter and a universal testing machine. The LCR meter's test voltage was 1mV, the frequency was 2MHz, and the universal testing machine's loading rate was 5μm / s.
[0086] In this comparative example, the mass fraction of neodymium iron boron (NdFeB) was 20 wt%.
[0087] like Figure 3 As shown, the sensor doped with 20 wt% NdFeB particles has lower sensitivity than the sensor with 8 wt% doping. This is because, at higher doping levels, the decrease in magnetic flux density under pressure on the amorphous filament is antagonistic to the impedance decrease segment of the GMI effect.
[0088] By comparing and analyzing the sensitivity curves of the flexible pressure sensors based on amorphous wires prepared in Examples 1, 1, 2, 3, and 4, the sensing performance of these sensors was investigated. Compared to Comparative Examples 1, 2, 3, and 4, the pressure sensing performance of the PDMS foam with 8wt% NdFeB particles embedded in PDMS, which contains a 680pF standard capacitor in series, and a 3.5-turn spiral amorphous wire embedded in PDMS, prepared in Example 1, was significantly improved. This indicates that artificially constructed LC resonance, double-layer structure design, and NdFeB doping adjustment are of great significance for optimizing pressure sensing performance.
[0089] Therefore, the PDMS foam containing 8wt% NdFeB particles embedded with 3.5-turn helical amorphous filaments, which is connected in series with a 680pF standard capacitor, has a wide sensing range (up to 1MPa), fast response and response times (both 40ms), good stability (over 15,000 cycles of loading), high sensitivity (approximately 6.6% / kPa), and a wide linear range (R0). 2 It exhibits performance characteristics of 0.99717 kPa (0-100 kPa), and its preparation method is simple and its structure is controllable, meeting the needs of practical applications. It demonstrates its application value in rehabilitation medical devices and also has great application potential in other pressure sensing fields.
[0090] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.
Claims
1. A method for fabricating an inductive sensor based on the triple giant magnetostatic effect, characterized in that, Specifically as follows: Amorphous wires are wound in a planar spiral manner and cured after being injected with silicone rubber to obtain a lower structure. A silicone rubber foam containing neodymium iron boron microparticles is prepared on the lower structure using a sugar template method to serve as the upper structure, resulting in an inductive sensor with a double-layer structure based on the triple giant magnetometry effect.
2. The method for fabricating an inductive sensor based on the triple giant magnetostatic effect according to claim 1, characterized in that, The specific method for preparing the lower layer structure is as follows: Several pillars are detachably embedded in the mold, and amorphous wires are wound on the pillars in a planar spiral manner. Then, the frame is placed above the mold, and silicone rubber prepolymer and curing agent after vacuum degassing are injected into the frame. After curing at 150 °C for 15 min, the lower structure is obtained.
3. The method for fabricating an inductive sensor based on the triple giant magnetostatic effect according to claim 2, characterized in that, The mold, support column, and frame are all made of stainless steel.
4. The method for fabricating an inductive sensor based on the triple giant magnetostatic effect according to claim 1, characterized in that, The amorphous filament is composed of Co. 68.7 Fe4Si 11 B 13 Ni1Mo 2.3 It has a diameter of 30 mm and a winding number of 3.5 turns.
5. The method for fabricating an inductive sensor based on the triple giant magnetostatic effect according to claim 2, characterized in that, The specific method for preparing the upper structure is as follows: Remove several pillars from the mold, pour granulated sugar into the frame and flatten it. Then pour the mixture of neodymium iron boron powder, silicone rubber prepolymer and curing agent into the frame and smooth the surface. Then cure at 150 ℃ for 15 min. After demolding, soak the product in water to dissolve the granulated sugar and form a sponge structure to obtain the upper structure.
6. The method for fabricating an inductive sensor based on the triple giant magnetostatic effect according to claim 1, characterized in that, The neodymium iron boron microparticles have a particle size of 5 μm, and the white sugar in the sugar template method has a particle size of 300-600 μm.
7. An inductive sensor based on the triple giant magnetotropic effect obtained by the preparation method according to any one of claims 1 to 6.
8. The application of an inductive sensor based on the triple giant magnetosphere effect as described in claim 7 in an intelligent finger separator for dynamically monitoring the rehabilitation effect of the hand in hemiplegic patients.
9. The application according to claim 8, characterized in that, The intelligent finger-splitter is obtained by integrating an inductive sensor with a standard capacitor connected in series onto the finger-splitter.