Three-dimensional array type magnetic tactile sensor and manufacturing method thereof

Abstract

The invention relates to the technical field of tactile sensing, in particular to a three-dimensional array type magnetic tactile sensor and a manufacturing method thereof. The three-dimensional array type magnetic tactile sensor comprises a flexible circuit board layer, an elastic layer and a flexible magnet layer which are sequentially stacked and bonded from bottom to top, when the flexible magnet layer deforms due to external pressure, the surrounding magnetic field intensity is changed, and the flexible circuit board layer measures external force by sensing the magnetic field change of the flexible magnet layer. The elastic layer is used for expanding the external force measurement range of the flexible circuit board layer. The flexible magnet layer comprises a top-layer flexible body and a plurality of flexible magnets embedded in the top-layer flexible body, and the flexible magnets are used as contacts. The device simulates human hand touch perception, has a wide force measurement range, can accurately detect tiny force change, and improves sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of tactile sensing, and in particular to a three-dimensional array magnetic tactile sensor and a manufacturing method thereof. Background Art

[0002] Tactile perception plays a central role in robotics, enabling robots to sense and respond to the external environment in a way that is close to that of humans. High-performance tactile sensors enhance the robot's capabilities in fine manipulation, object recognition, and human-machine interaction, and are essential for realizing intelligent and flexible robotic systems. In daily life, human hands can grasp and manipulate objects of various shapes and sizes because the rich tactile receptors in the finger skin can sense the three-dimensional force of contact and adjust the finger's grasping force in real time to ensure safe grasping and manipulation. Therefore, it is particularly urgent to develop high-performance three-dimensional force sensor technology to meet the demand for tactile feedback.

[0003] In recent years, the research on three-dimensional force sensors has made some progress, and tactile sensors based on various mechanisms such as resistance, capacitance, piezoelectricity and optics have been developed. Compared with three-dimensional force tactile sensors based on other mechanisms, magnetic sensors have the advantages of high sensitivity, high resolution, non-contact measurement, strong stability and resistance to environmental interference, making them an important direction in the field of tactile sensing. The principle of magnetic tactile sensors is to use a mixture of magnetic and flexible materials as a magnetic field source. When an external force acts on a magnetic material, it will cause deformation or displacement. By detecting the change in the magnetic field with a magnetic sensor, the magnitude and direction of the external force can be obtained, thereby achieving tactile perception. Based on this principle, contact sensors of different shapes, sizes and sensitivities can be designed. The integration of such sensors can enhance the robot's ability to grasp fragile objects, deformable objects and identify object properties.

[0004] In previous studies, the structural designs of magnetic composite materials are varied, but most tactile sensors based on the principle of magnetic field detection have problems such as a small measurement range at high sensitivity or poor sensitivity at a large measurement range. Summary of the invention

[0005] In view of the above problems, the object of the present invention is to provide a three-dimensional array magnetic tactile sensor and a manufacturing method thereof, so as to solve the problem that the existing tactile sensors have a small measurement range under high sensitivity or poor sensitivity under a large measurement range.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] On the one hand, the present invention provides a three-dimensional array magnetic tactile sensor, including a flexible circuit board layer, an elastic layer and a flexible magnetic layer stacked and bonded in sequence from bottom to top, wherein the flexible magnetic layer changes the surrounding magnetic field strength when deformed by external pressure, the flexible circuit board layer measures the external force by sensing the magnetic field change of the flexible magnetic layer, and the elastic layer is used to expand the external force measurement range of the flexible circuit board layer.

[0008] The flexible magnet layer includes a top flexible body and a plurality of flexible magnets embedded in the top flexible body. The flexible magnets are used as contacts and can be deformed by external pressure, thereby changing the surrounding magnetic field strength.

[0009] The front surface of the flexible magnet is a square structure protruding from the upper surface of the top flexible body, and the bottom surface of the flexible magnet is a cross hollow structure concave on the lower surface of the top flexible body.

[0010] The elastic layer includes a middle-layer flexible body and a plurality of springs embedded in the middle-layer flexible body.

[0011] The flexible circuit board layer includes a bottom flexible body and a flexible hard brush circuit board embedded above the bottom flexible body. The flexible hard brush circuit board is provided with a plurality of chips corresponding to the flexible magnets one by one.

[0012] The chip is a Hall sensor, and a plurality of Hall sensors are arranged in a square array.

[0013] Another aspect of the present invention provides a method for manufacturing the three-dimensional array magnetic tactile sensor as described above, comprising the following steps:

[0014] Manufacturing a flexible magnetic layer by means of a magnetic layer mold;

[0015] forming an elastic layer by means of an elastic layer mold;

[0016] Making flexible circuit board layers;

[0017] The flexible circuit board layer, the elastic layer and the flexible magnetic layer are bonded in sequence.

[0018] The magnetic layer mold includes a magnetic layer lower mold and a magnetic layer upper mold, wherein the inner surface array of the magnetic layer lower mold has a plurality of square grooves, and the inner surface array of the magnetic layer upper mold has cross protrusions corresponding one by one to the square grooves on the magnetic layer lower mold; when the magnetic layer upper mold and the magnetic layer lower mold are molded together, the cross protrusions are accommodated in the corresponding square grooves, and a molding gap is left between the cross protrusions and the square grooves.

[0019] The process of making the flexible magnetic layer comprises the following steps:

[0020] NdFeB magnetic powder and silica gel solution are mixed into a mixed solution at a mass ratio of 2:1, and the mixed solution is poured into each square groove on the mold under the magnet layer, and then a vacuum operation is performed;

[0021] pouring a layer of silica gel on the inner surface of the mold below the magnet layer;

[0022] The upper mold of the magnetic layer and the lower mold of the magnetic layer are molded and fixed;

[0023] Put it in a drying oven for curing;

[0024] Opening the mold to obtain a flexible magnetic layer having a flexible magnet on the upper surface and a cross groove on the lower surface;

[0025] The top flexible body is magnetized to make it have magnetic field characteristics.

[0026] The elastic layer mold comprises an elastic layer lower mold and an elastic layer upper mold, and the inner surfaces of the elastic layer lower mold and the elastic layer upper mold are respectively arrayed with a plurality of one-to-one corresponding lower spring fixing columns and upper spring fixing columns;

[0027] The process of making the elastic layer comprises the following steps:

[0028] A spring is placed on each lower spring fixing column of the lower mold of the elastic layer, and the upper mold of the elastic layer and the lower mold of the elastic layer are molded and fixed, and the upper end of each spring is fixed by the corresponding upper spring fixing column;

[0029] pouring silicone liquid into the cavity through a pouring hole provided on the mold on the elastic layer;

[0030] Curing and forming.

[0031] The advantages and positive effects of the present invention are as follows: the present invention provides a three-dimensional array magnetic tactile sensor that simulates the tactile perception of human hands, has a wide force measurement range, can accurately detect tiny force changes, and improves sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of a three-dimensional array magnetic tactile sensor of the present invention;

[0033] Figure 2 It is a schematic structural diagram of the flexible magnetic layer in the present invention;

[0034] Figure 3 It is a structural schematic diagram of the flexible hard brush circuit board in the present invention;

[0035] Figure 4 Schematic diagrams of the structure of the magnetic layer mold in the present invention: (a) is a schematic diagram of the structure of the upper mold of the magnetic layer, and (b) is a schematic diagram of the structure of the lower mold of the magnetic layer;

[0036] Figure 5 Schematic diagrams of the structure of the elastic layer mold in the present invention: (a) is a schematic diagram of the structure of the upper mold of the elastic layer, and (b) is a schematic diagram of the structure of the lower mold of the elastic layer.

[0037] In the figure: 1-lower mold of magnetic layer, 2-square groove, 3-upper mold of magnetic layer, 4-cross protrusion, 5-lower mold of elastic layer, 6-lower spring fixing column, 7-upper mold of elastic layer, 8-upper spring fixing column, 10-cross hollow structure, 11-flexible magnet, 12-top flexible body, 13-spring, 14-middle flexible body, 15-chip, 16-flexible hard brush circuit board, 17-bottom flexible body. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] See also Figures 1 to 3 As shown, one embodiment of the present invention provides a three-dimensional array magnetic tactile sensor, including a flexible circuit board layer, an elastic layer and a flexible magnetic layer stacked and bonded in sequence from bottom to top, wherein the flexible magnetic layer changes the surrounding magnetic field strength when deformed by external pressure, the flexible circuit board layer measures the external force by sensing the magnetic field change of the flexible magnetic layer, and the elastic layer is used to expand the external force measurement range of the flexible circuit board layer.

[0040] See also Figure 1 and Figure 2 As shown, in an embodiment of the present invention, the flexible magnetic layer includes a top flexible body 12 and a plurality of flexible magnets 11 embedded in the top flexible body 12. The flexible magnets 11 are used as contacts and can be deformed by external pressure, thereby changing the surrounding magnetic field strength.

[0041] Specifically, the front of the flexible magnet 11 is a square structure protruding from the upper surface of the top flexible body 12, which can simultaneously detect normal force and radial force; the bottom of the flexible magnet 11 is a cross hollow structure 10 recessed into the lower surface of the top flexible body 12 to improve the sensitivity of the sensor.

[0042] See also Figure 1 As shown, in the embodiment of the present invention, the elastic layer includes a middle-layer flexible body 14 and a plurality of springs 13 embedded in the middle-layer flexible body 14 .

[0043] See also Figure 1 , Figure 3 As shown, in an embodiment of the present invention, the flexible circuit board layer includes a bottom flexible body 17 and a flexible hard brush circuit board 16 embedded above the bottom flexible body 17, and the flexible hard brush circuit board 16 is provided with a plurality of chips 15 corresponding to the flexible magnets 11 one by one.

[0044] In this embodiment, the chip 15 is a Hall sensor, and a plurality of Hall sensors are arranged in a 3x3 array. Correspondingly, the flexible magnets 11 are arranged in a 3x3 array on the top flexible body 12. Specifically, the top flexible body 12, the middle flexible body 14 and the bottom flexible body 17 are all organic elastomers made of silicone material, specifically Excof le 00-30 silicone.

[0045] The present invention provides a three-dimensional array magnetic tactile sensor, which is designed in a sandwich structure. When the top flexible magnetic layer is deformed by external pressure, the surrounding magnetic field strength is changed. These changes are detected by the Hall sensor embedded in the bottom layer, and then converted into electrical signals through a flexible printed circuit board (FPCB), thereby obtaining tactile perception. The middle layer is a combination of a soft organic elastomer (Excof l e00-30) and a spring, which expands the external force measurement range of the sensor, so the present invention has the advantages of high sensitivity, wide range and.

[0046] Another embodiment of the present invention provides a method for manufacturing the three-dimensional array magnetic tactile sensor in the above embodiment, comprising the following steps:

[0047] Manufacturing a flexible magnetic layer by means of a magnetic layer mold;

[0048] forming an elastic layer by means of an elastic layer mold;

[0049] Making flexible circuit board layers;

[0050] The flexible circuit board layer, elastic layer and flexible magnetic layer were bonded in turn with Excof le 00-30 silicone solution and then put into a drying oven for curing for 2 hours. Finally, the flexible circuit board layer, elastic layer and flexible magnetic layer were firmly bonded together to form a complete sensor structure.

[0051] See also Figure 4 As shown in (a)-(b), in an embodiment of the present invention, the magnetic layer mold includes a magnetic layer lower mold 1 and a magnetic layer upper mold 3, wherein the inner surface array of the magnetic layer lower mold 1 has 3x3 square grooves 2, and the inner surface array of the magnetic layer upper mold 3 has cross protrusions 4 corresponding to the square grooves 2 on the magnetic layer lower mold 1 one by one; when the magnetic layer upper mold 3 and the magnetic layer lower mold 1 are molded together, the cross protrusions 4 are accommodated in the corresponding square grooves 2, and a molding gap is left between the cross protrusions 4 and the square grooves 2.

[0052] In an embodiment of the present invention, the process of manufacturing the flexible magnetic layer includes the following steps:

[0053] NdFeB magnetic powder and Excof le 00-30 silica gel solution are mixed into a mixed liquid at a mass ratio of 2:1, and the mixed liquid is poured into the square grooves 2 of the 3×3 square array on the mold 1 under the magnet layer. The size of each square groove 2 is 4mm*4mm, the depth is 3mm, the left and right intervals between the square grooves 2 are 4.5mm, and the front and back intervals are 7.5mm; then vacuum treatment is performed, and a Fujiwara oil-free vacuum pump is used for operation, and then the mold is placed in a drying oven (model is Lichen Technology Electric Heating Constant Temperature Drying Oven, set temperature is 40C°) and dried for 5 minutes to form a semi-liquid state;

[0054] Then, the excess mixture on the mold surface is removed, and a layer of Excof le 00-30 silica gel solution is poured again, the upper mold 3 of the magnetic layer is molded and fixed with the lower mold 1 of the magnetic layer, and then the mold is placed in a drying oven for curing for 2 hours;

[0055] After curing, the flexible magnetic layer is taken out from the mold, and the upper surface of the flexible magnetic layer has the flexible magnetic layer 11, and the lower surface has the cross hollow structure 10 corresponding to the flexible magnetic layer 11 and embedded inwards;

[0056] Finally, the flexible magnet 11 is magnetized to have magnetic field characteristics.

[0057] See also Figure 5 As shown in (a)-(b), in an embodiment of the present invention, the elastic layer mold includes an elastic layer lower mold 5 and an elastic layer upper mold 7, and the inner surfaces of the elastic layer lower mold 5 and the elastic layer upper mold 7 are respectively arrayed with a plurality of one-to-one corresponding lower spring fixing columns 6 and upper spring fixing columns 8.

[0058] In an embodiment of the present invention, the process of making the elastic layer includes the following steps:

[0059] A spring 13 is placed on each lower spring fixing column 6 of the elastic layer lower mold 5, and the elastic layer upper mold 7 is molded and fixed with the elastic layer lower mold 5, and the upper end of each spring 13 is fixed by the corresponding upper spring fixing column 8;

[0060] Pour the silicone liquid into the cavity through the pouring hole provided on the elastic layer upper mold 7;

[0061] The bottom row of the sensor array is S1-S3, the middle row is S4-S6, and the top row is S7-S9, where the magnets, springs, and Hall sensors work together to realize the force sensing function.

[0062] The advantages of the present invention are: 1) scalable flexible sensing to simulate human tactile perception; 2) wide force measurement range and high sensitivity: by optimizing the hardness of the magnet and adding a spring layer, the sensor has a wide force measurement range, the normal force measurement range is as high as 0-16N, the minimum resolution is 10mN, and it can accurately detect small force changes. The tangential force measurement range is -7N to 7N, and it has a high sensitivity of 57.625 1N-, which is better than existing flexible sensors.

[0063] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A three-dimensional array magnetic tactile sensor, characterized in that: It includes a flexible circuit board layer, an elastic layer and a flexible magnetic layer which are stacked and bonded in sequence from bottom to top. When the flexible magnetic layer is deformed by external pressure, the surrounding magnetic field strength is changed. The flexible circuit board layer measures the external force by sensing the magnetic field change of the flexible magnetic layer. The elastic layer is used to expand the external force measurement range of the flexible circuit board layer.

2. The three-dimensional array magnetic tactile sensor according to claim 1, characterized in that: The flexible magnetic layer comprises a top flexible body (12) and a plurality of flexible magnets (11) embedded in the top flexible body (12). The flexible magnets (11) are used as contacts and can be deformed under external pressure, thereby changing the surrounding magnetic field strength.

3. The three-dimensional array magnetic tactile sensor according to claim 2, characterized in that: The front surface of the flexible magnet (11) is a square structure protruding from the upper surface of the top flexible body (12), and the bottom surface of the flexible magnet (11) is a cross hollow structure (10) concave into the lower surface of the top flexible body (12).

4. The three-dimensional array magnetic tactile sensor according to claim 2, characterized in that: The elastic layer comprises a middle-layer flexible body (14) and a plurality of springs (13) embedded in the middle-layer flexible body (14).

5. The three-dimensional array magnetic tactile sensor according to claim 2, characterized in that: The flexible circuit board layer comprises a bottom flexible body (17) and a flexible hard brush circuit board (16) embedded above the bottom flexible body (17); the flexible hard brush circuit board (16) is provided with a plurality of chips (15) corresponding one-to-one to the flexible magnets (11).

6. The three-dimensional array magnetic tactile sensor according to claim 5, characterized in that: The chip (15) is a Hall sensor, and a plurality of Hall sensors are arranged in a square array.

7. A method for manufacturing a three-dimensional array magnetic tactile sensor according to any one of claims 2 to 6, characterized in that: The following steps are involved: Manufacturing a flexible magnetic layer by means of a magnetic layer mold; forming an elastic layer by means of an elastic layer mold; Making flexible circuit board layers; The flexible circuit board layer, the elastic layer and the flexible magnetic layer are sequentially bonded and cured into one body.

8. The method according to claim 7, characterized in that: The magnetic layer mold comprises a magnetic layer lower mold (1) and a magnetic layer upper mold (3), wherein the inner surface array of the magnetic layer lower mold (1) has a plurality of square grooves (2), and the inner surface array of the magnetic layer upper mold (3) has cross protrusions (4) corresponding one-to-one to the square grooves (2) on the magnetic layer lower mold (1); when the magnetic layer upper mold (3) and the magnetic layer lower mold (1) are molded together, the cross protrusions (4) are accommodated in the corresponding square grooves (2), and a molding gap is left between the cross protrusions (4) and the square grooves (2).

9. The manufacturing method according to claim 8, characterized in that: The process of making the flexible magnetic layer comprises the following steps: NdFeB magnetic powder and silica gel solution are mixed into a mixed liquid at a mass ratio of 2:1, and the mixed liquid is poured into each square groove (2) on the lower mold (1) of the magnetic layer, and then a vacuum operation is performed; Casting a layer of silica gel on the inner surface of the mold (1) below the magnetic layer; The upper mold (3) of the magnetic layer and the lower mold (1) of the magnetic layer are molded and fixed; Put it in a drying oven for curing; Opening the mold to obtain a flexible magnetic layer having a flexible magnet (11) on the upper surface and a cross groove on the lower surface; The top flexible body (12) is magnetized so that the top flexible body (12) has magnetic field characteristics.

10. The manufacturing method according to claim 7, characterized in that: The elastic layer mold comprises an elastic layer lower mold (5) and an elastic layer upper mold (7), and the inner surfaces of the elastic layer lower mold (5) and the elastic layer upper mold (7) are respectively arrayed with a plurality of one-to-one corresponding lower spring fixing columns (6) and upper spring fixing columns (8); The process of making the elastic layer comprises the following steps: A spring (13) is placed on each lower spring fixing column (6) of the elastic layer lower mold (5), and the elastic layer upper mold (7) and the elastic layer lower mold (5) are molded and fixed, and the upper end of each spring (13) is fixed by a corresponding upper spring fixing column (8); Pouring silica gel liquid into the mold cavity through a pouring hole provided on the elastic layer upper mold (7); Curing and forming.

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