Flexible multi-modal multi-dimensional force sensor and preparation method thereof

Abstract

The invention provides a flexible multi-modal multi-dimensional force sensor and a preparation method thereof, and belongs to the technical field of structural design and assembly of sensitive parts in multi-modal three-dimensional force sensors. The flexible multi-mode and multi-dimensional force sensor comprises a PCB base, and a plurality of metal coils are distributed on the PCB base; the flexible shell is located on the side, away from the PCB base, of the metal coil, and a cavity is formed in the side, away from the metal coil, of the flexible shell. The flexible permanent magnet structure is located in the cavity of the flexible shell, so that when external force acts on the flexible permanent magnet structure, the flexible permanent magnet structure downwards extrudes the flexible shell to deform, the metal coil generates induction current, and the magnitude and direction of the acting force applied to the flexible permanent magnet structure are determined according to the magnitude and direction of the induction current. According to the invention, the working principles of electromagnetic induction and capacitance detection are utilized, so that measurement of dynamic force can be realized, and detection of static force can also be realized.

Description

Technical Field

[0001] This disclosure belongs to the field of structural design and assembly technology of sensitive components in multimodal three-dimensional force sensors, specifically relating to a flexible multimodal multidimensional force sensor and its fabrication method. Background Technology

[0002] With the rapid development of cutting-edge technologies such as the Internet of Things, artificial intelligence, and bionic robots, wearable flexible sensors are showing broad application prospects. Traditional flexible sensors include resistive, capacitive, and piezoelectric types. Compared with traditional sensors, magnetic sensors are more suitable for use in the automotive, medical, consumer electronics, and communications fields. Flexible magnetic sensors are based on the principles of piezomagnetism, the Hall effect, electromagnetic induction, and magnetostriction, achieving information interaction with targets without contact.

[0003] In the field of magnetic sensor research and development, the core device architecture consists of a flexible sensor unit and a coil assembly. Conventional assembly structures suffer from poor reliability and low sensitivity. Most current mainstream magnetic sensors are limited to the detection of unidirectional force signals and cannot detect multidimensional forces; this greatly limits the application scenarios of the sensors. At the same time, this assembly structure is easily affected by the external environment, reducing the stability of the sensor's detection performance. Summary of the Invention

[0004] This disclosure aims to at least solve one of the technical problems existing in the prior art, and to provide a flexible multimodal multidimensional force sensor and its fabrication method.

[0005] One aspect of this disclosure provides a flexible multimodal multidimensional force sensor, comprising: PCB base; Multiple metal coils are distributed on the PCB base; A flexible housing is located on the side of the metal coil away from the PCB base, and a cavity is provided on the side of the flexible housing away from the metal coil. A flexible permanent magnet structure is located inside the cavity of the flexible shell. When an external force is applied to the flexible permanent magnet structure, the flexible permanent magnet structure presses down on the flexible shell to deform it. The metal coil generates an induced current, and the magnitude and direction of the force applied to the flexible permanent magnet structure are determined according to the magnitude and direction of the induced current.

[0006] Optionally, the plurality of metal coils are radially distributed around the center of the PCB base.

[0007] Optionally, the plurality of metal coils are arranged radially symmetrically along the PCB base.

[0008] Optionally, the metal coil is helical.

[0009] Optionally, the flexible permanent magnet structure has a preset distance from the bottom of the cavity.

[0010] Optionally, the flexible permanent magnet structure is a solid hemispherical structure, with the bottom of the solid hemispherical structure corresponding to the bottom of the cavity.

[0011] Optionally, the flexible outer shell is bonded to and covers the metal coil, and the flexible permanent magnet structure is bonded to the inner wall of the cavity.

[0012] Optionally, the flexible permanent magnet structure is formed of PDMS and a permanent magnet material doped in the PDMS; The flexible shell is made of PDMS.

[0013] Optionally, the PCB base is provided with a plurality of lead electrodes, each of which is connected to the metal coil.

[0014] In another aspect of this disclosure, a method for fabricating the flexible multimodal multidimensional force sensor described above is proposed, the method comprising: A mold is provided, and the flexible permanent magnet structure and the flexible shell are fabricated sequentially using the mold; Obtain multiple metal coils and a PCB base; The plurality of metal coils are connected to the PCB base, the flexible permanent magnet structure is bonded to the cavity of the flexible shell, and the flexible shell is further bonded to the metal coils to obtain a flexible multimodal multidimensional force sensor.

[0015] This disclosure proposes a flexible multimodal multidimensional force sensor and its fabrication method. The flexible multimodal multidimensional force sensor includes: a PCB base; multiple metal coils distributed on the PCB base; a flexible shell located on the side of the metal coils away from the PCB base, and a cavity formed on the side of the flexible shell away from the metal coils; and a flexible permanent magnet structure located within the cavity of the flexible shell. When an external force is applied to the flexible permanent magnet structure, the flexible permanent magnet structure deforms by pressing downwards against the flexible shell, and the metal coils generate an induced current. The magnitude and direction of the force applied to the flexible permanent magnet structure are determined based on the magnitude and direction of the induced current. This disclosure utilizes the working principles of electromagnetic induction and capacitance detection, enabling not only the measurement of dynamic forces but also the detection of static forces. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the flexible multimodal multidimensional force sensor structure disclosed in this paper; Figure 2 This is a schematic diagram of the flexible permanent magnet structure disclosed herein; Figure 3 This is a schematic diagram of the hollow cylindrical PDMS flexible shell disclosed in this invention. Figure 4 This is a schematic flowchart of the fabrication method of the flexible permanent magnet material multidimensional force sensor disclosed in this paper; Figure 5 This is a schematic diagram of a mold used in this disclosure to prepare a hemispherical flexible permanent magnet structure; Figure 6 This is a schematic diagram of a mold used in this disclosure to prepare a flexible shell. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this disclosure and represent a part of the embodiments of this disclosure, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the protection scope of this disclosure.

[0018] like Figures 1 to 3 As shown, one aspect of this disclosure proposes a flexible multimodal multidimensional force sensor, including a PCB base 70, multiple metal coils 60, a flexible shell 50, and a flexible permanent magnet structure 40; wherein, the multiple metal coils 60 are distributed above the PCB base 70; the flexible shell 50 is located on the side of the metal coils 60 away from the PCB base 70, and a cavity is provided on the side of the flexible shell 50 away from the metal coils 60; the flexible permanent magnet structure 40 is located in the cavity of the flexible shell 50, so that when an external force is applied to the flexible permanent magnet structure 40, the flexible permanent magnet structure 40 presses the flexible shell 50 downward to deform, and the metal coils 60 generate an induced current, and the magnitude and direction of the force applied to the flexible permanent magnet structure 40 are determined according to the magnitude and direction of the induced current.

[0019] In this embodiment, by setting multiple metal coils at different positions on the bottom of the flexible shell and setting a flexible permanent magnet structure inside the flexible shell, high-precision detection of three-dimensional dynamic and static forces is achieved through the dual-mode synergy of electromagnetic induction and capacitance detection.

[0020] It should be noted that this embodiment does not specifically limit the materials of the flexible shell and the flexible permanent magnet structure. For example, the flexible shell is made of PDMS, and the flexible permanent magnet structure is formed by PDMS and permanent magnet materials doped in the PDMS, which not only ensures the flexibility but also makes the permanent magnet structure magnetic.

[0021] It should be further noted that this embodiment does not specifically limit the fixing method between the flexible permanent magnet structure, the flexible shell, and the metal coil. For example, the flexible permanent magnet structure is bonded to the inner wall of the cavity, and the flexible shell is bonded directly above the metal coil. It should be understood that the bottom of the flexible shell should completely cover the multiple metal coils, and the center of the flexible shell should correspond to the center position of the multiple metal coils to ensure the accuracy of the detection.

[0022] It should also be understood that there is a certain distance between the bottom of the flexible permanent magnet structure and the bottom of the cavity. In other words, the flexible permanent magnet structure can be bonded to the upper part of the inner wall of the cavity, so that there is a hollow area between the flexible permanent magnet structure and the bottom of the flexible shell, providing deformation space. When an external force is applied, the flexible permanent magnet structure moves downward, and the hollow area allows it to deform fully, thereby more effectively squeezing the bottom metal coil, increasing the change in magnetic flux, improving the strength of the induced current signal, and increasing sensitivity.

[0023] It should be noted that this embodiment does not specifically limit the thickness and height of the flexible shell, which can be set according to actual needs. Generally speaking, a smaller thickness of the flexible shell allows the flexible permanent magnet hemispherical structure to contact the bottom metal coil under a smaller force, thus obtaining better electrical signal data. By reducing the height of the PDMS flexible shell, the flexible permanent magnet hemispherical structure can be changed to squeeze the bottom metal coil to generate a voltage signal with a smaller displacement. The height of the PDMS flexible shell can be modified according to the actual requirements for sensor sensitivity.

[0024] It should be noted that this embodiment does not specifically limit the shape of the flexible permanent magnet structure; for example, such as... Figure 1 and Figure 2 As shown, the flexible permanent magnet structure 40 can preferably be a solid hemispherical structure, which can provide a stable force application point under the action of force. The bottom of the solid hemispherical structure corresponds to the bottom of the cavity, that is, the spherical bottom of the flexible permanent magnet structure faces the bottom of the cavity, and the planar top of the flexible permanent magnet structure is flush with the top of the flexible shell.

[0025] Furthermore, such as Figure 1 As shown, in this embodiment, multiple metal coils 60 are radially distributed around the center of the PCB base 70. That is, one metal coil is located at the center of the PCB base, and the remaining metal coils are arranged around the periphery of the metal coil in sequence. The number of metal coils can be selected according to actual needs, and the number of turns and diameter of the metal coils can be changed according to performance requirements.

[0026] Furthermore, such as Figure 1As shown, multiple metal coils 60 are arranged symmetrically along the radial direction of the PCB base 70. In other words, the multiple metal coils are centrally symmetrical with respect to the center point. This symmetrical layout can ensure that the sensor responds uniformly to the X / Y / Z triaxial forces without any detection blind spots. At the same time, when the flexible permanent magnet structure deforms, the symmetrically arranged metal coils maximize the change in magnetic flux and the induced current signal, resulting in high detection sensitivity.

[0027] Furthermore, such as Figure 1 As shown, the metal coil 60 is spiral-shaped, and the multi-turn structure of the spiral coil significantly increases the effective magnetic field area.

[0028] It should be noted that the number and number of turns of the metal coils in this embodiment can be modified according to the sensitivity requirements of the sensor, thereby improving the flexibility of the sensor's application. That is, by adjusting the layout and number of the metal coils, the sensor's sensitivity and multi-directional force testing performance can be optimized. Furthermore, the metal coils should be positioned around and directly below the soft magnetic material casing. Furthermore, such as Figure 1 As shown, a plurality of lead electrodes 71 are provided on the PCB base 70, and each lead electrode 71 is connected to the metal coil 60.

[0029] Based on the above structure, the sensor detection principle of this embodiment is as follows: like Figure 1 As shown, when an external force is applied to the flexible permanent magnet structure 40, it will cause displacement. This displacement will compress the metal coil 60 at the bottom of the flexible shell 50, causing a change in the magnetic flux of the metal coil 60 and generating an induced voltage signal. After the signal is collected and processed, the effective force parameters can be obtained. Multidimensional force detection is achieved through the metal coils 60 at different positions at the bottom of the flexible shell 50. When the magnetic material is subjected to an external force in the Z-axis direction, it will compress the metal coil 60 at the center of the bottom of the flexible shell and generate a corresponding induced voltage. When subjected to a positive or negative force in the X-axis direction, it will compress the left or right metal coil 60 respectively; when subjected to a positive or negative force in the Y-axis direction, it will compress the front or rear metal coil 60 respectively. These induced voltages undergo the same acquisition and processing process, ultimately yielding the effective force signals for each axis. Based on the principle of force vector decomposition, an external force in any spatial direction can be decomposed into force components in the X, Y, and Z axes. By performing vector synthesis calculations on the force signals detected in each axis, the magnitude and direction information of the external force can be accurately obtained.

[0030] The principle of static force detection differs from that of dynamic force detection. Static force detection is based on the principle of capacitance detection, treating adjacent metal coils as capacitor plates and the flexible permanent magnet structure and surrounding air as dielectrics. When a force is applied to the flexible permanent magnet structure material, it will deform and cover part of the metal coil. By analyzing the change in capacitance between the two metal coil plates, the absolute location and magnitude of the static force can be obtained.

[0031] Furthermore, the detected signal is transmitted to the PCB base via lead electrodes. The force signal obtained from subsequent processing is combined with a large-scale artificial intelligence model. For example, a support vector machine (SVM) model can be used to perform force signal regression analysis, effectively distinguishing subtle differences in force signals in classification tasks. The LTSM model can achieve time-series prediction and dynamic trend analysis of force signals. By capturing time dependencies, future trends can be predicted based on historical force signal sequences, transforming the originally abstract force signal into precise decisions that can guide actual operations, thus realizing the intelligence of the sensor.

[0032] In this disclosure, a multi-dimensional dynamic and static force detection mechanism is constructed through an innovative assembly design of a flexible permanent magnet hemispherical structure and a metal coil: the Z-axis dynamic force detection relies on the coil located below the PDMS shell to sense changes in magnetic flux; the X / Y axes change the magnetic circuit characteristics of the corresponding coils through material displacement, and combined with the principle of force vector decomposition and synthesis, the magnitude and direction of multi-dimensional dynamic forces in any space can be accurately captured; adjacent coils are used as capacitor plates, and the plates are covered by material compression, and the magnitude and direction of multi-dimensional static forces are obtained by analyzing the capacitance changes between the two plates. Furthermore, after acquiring accurate force and pressure signals, the solution is further combined with a large artificial intelligence model, which can perform in-depth analysis and feature extraction on force and pressure data under complex working conditions, breaking through the limitation of traditional sensors that only output basic data, greatly expanding its application scenarios in complex environments, and significantly improving its practical value and development potential.

[0033] like Figure 4 As shown, another aspect of this disclosure proposes a method for fabricating a flexible multimodal multidimensional force sensor, specifically including the following steps: S101. A mold is provided, comprising a first mold 10 having a hemispherical cavity, a second mold 20 having a cylindrical hollow cavity, and a third mold 30 having a cylindrical structure, such as... Figures 5 to 6 As shown.

[0034] S102. Provide PDMS solution and permanent magnet material, and pour the above materials into the first mold 10 to prepare a flexible permanent magnet structure 40, such as... Figure 5 As shown; S103. Provide a PDMS solution, pour the PDMS solution into the second mold 20 and the third mold 30 to prepare a PDMS flexible shell 50 with a hollow columnar structure, such as... Figure 6 As shown; S104. Provide a winding machine and metal wire. Use the winding machine to wind the metal coil around a specified mold to obtain a spiral metal coil. The number of turns and diameter of the metal coil can be changed according to performance requirements. At the same time, obtain a PCB base 70 with lead electrodes. S105. Assemble the flexible permanent magnet structure 40 with the PDMS flexible shell 50 and the PCB base 70. The metal coil is fixed to the bottom of the PDMS flexible shell, and the components are fully fixed with high viscosity glue to obtain the flexible permanent magnet multimodal multidimensional force sensor.

[0035] This disclosure presents an innovative assembly design that combines a flexible permanent magnet hemispherical structure with a spiral metal coil. The metal coil is symmetrically distributed in a circular shape under the flexible PDMS shell. Based on the unique shape of the flexible permanent magnet hemispherical structure, the assembly of the flexible permanent magnet hemispherical structure with the flexible PDMS shell can accurately and effectively acquire the magnitude and direction of multimodal and multidimensional forces, breaking through the limitations of traditional single-sided detection. Combined with AI large models, it can further expand the application of sensors in complex scenarios.

[0036] This disclosure proposes a flexible multimodal multidimensional force sensor and its fabrication method, which has the following advantages over the prior art: This disclosure breaks through the limitation of traditional sensors that can only realize unidirectional force detection. It adopts a multidimensional spiral metal coil layout to realize the accurate capture of multimodal three-dimensional force signals. The spiral coil can not only detect dynamic forces, but also realize static force detection due to its special structure. It realizes the detection of three-dimensional dynamic forces and static forces. By optimizing the magnetic circuit and coil layout, the sensitivity and detection accuracy of the sensor are significantly improved.

[0037] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A flexible multimodal multidimensional force sensor, characterized in that, include: PCB base; Multiple metal coils are distributed on the PCB base; A flexible housing is located on the side of the metal coil away from the PCB base, and a cavity is provided on the side of the flexible housing away from the metal coil. A flexible permanent magnet structure is located inside the cavity of the flexible shell. When an external force is applied to the flexible permanent magnet structure, the flexible permanent magnet structure presses down on the flexible shell to deform it. The metal coil generates an induced current, and the magnitude and direction of the force applied to the flexible permanent magnet structure are determined according to the magnitude and direction of the induced current.

2. The flexible multimodal multidimensional force sensor according to claim 1, characterized in that, The plurality of metal coils are distributed radially outward from the center of the PCB base.

3. The flexible multimodal multidimensional force sensor according to claim 2, characterized in that, The plurality of metal coils are arranged symmetrically along the radial direction of the PCB base.

4. The flexible multimodal multidimensional force sensor according to claim 3, characterized in that, The metal coil is spiral-shaped.

5. The flexible multimodal multidimensional force sensor according to claim 1, characterized in that, The flexible permanent magnet structure is at a predetermined distance from the bottom of the cavity.

6. The flexible multimodal multidimensional force sensor according to claim 1, characterized in that, The flexible permanent magnet structure is a solid hemispherical structure, with the bottom of the solid hemispherical structure corresponding to the bottom of the cavity.

7. The flexible multimodal multidimensional force sensor according to claim 1, characterized in that, The flexible outer shell is bonded to and covers the metal coil, and the flexible permanent magnet structure is bonded to the inner wall of the cavity.

8. The flexible multimodal multidimensional force sensor according to claim 1, characterized in that, The flexible permanent magnet structure is formed from PDMS and permanent magnet material doped in the PDMS; The flexible outer shell is made of PDMS.

9. The flexible multimodal multidimensional force sensor according to claim 1, characterized in that, The PCB base is provided with multiple lead electrodes, and each lead electrode is connected to the metal coil.

10. A method for fabricating a flexible multimodal multidimensional force sensor as described in any one of claims 1-9, characterized in that, The method includes: A mold is provided, and the flexible permanent magnet structure and the flexible shell are fabricated sequentially using the mold; Obtain multiple metal coils and a PCB base; The plurality of metal coils are connected to the PCB base, the flexible permanent magnet structure is bonded to the cavity of the flexible shell, and the flexible shell is further bonded to the metal coils to obtain a flexible multimodal multidimensional force sensor.

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