Mutual inductance type tactile sensing unit and sensor

Abstract

The invention discloses a mutual inductance type tactile sensing unit, and relates to the technical field of flexible bionic tactile sensing devices. The mutual inductance type tactile sensing unit comprises at least two magnetic induction coils which are arranged in a stacked mode, and a first insulating layer used for electrically isolating the magnetic induction coils is arranged between every two adjacent magnetic induction coils; at least one of the first insulating layers is an elastic insulating layer formed by one or more layers of elastomers and is used for supporting the magnetic induction coils to approach each other under the action of external force and supporting the distance between the magnetic induction coils to recover after the external force disappears; pressure sensing parameters are obtained by detecting the inductance change of the magnetic induction coil. By adopting the mutual inductance type multi-coil design, compared with the eddy current induction principle in the prior art, the device has the advantages of high sensitivity and low requirement on the surrounding environment, and the detection result is efficient and reliable.

Description

Technical Field

[0001] This invention belongs to the field of flexible bionic tactile sensor technology, and particularly relates to a mutual inductance tactile sensing unit and sensor. Background Technology

[0002] Currently, most bionic tactile sensors employ a combination of stacked metal films, elastomers, and magnetic coils. Based on the principle of eddy current induction, the elastomer contracts under external force, causing changes in the positions of the metal film and magnetic coils, which in turn induces changes in eddy currents, thus converting them into detected pressure. Although this approach can detect pressure, its sensitivity is low, and the actual detection effect is not ideal.

[0003] In addition, this method has high requirements for the surrounding environment. If there is a strong magnetic field or metal in the outside, it will seriously affect the detection results. Summary of the Invention

[0004] In view of this, one object of the present invention is to provide a mutual inductance tactile sensing unit to solve the problems of low detection sensitivity and high requirements for the surrounding environment in the prior art.

[0005] In some illustrative embodiments, the mutual inductance tactile sensing unit includes: at least two stacked magnetic induction coils, with a first insulating layer between each pair of adjacent magnetic induction coils for electrical isolation between the magnetic induction coils; at least one of the first insulating layers is an elastic insulating layer formed of one or more layers of elastomer, for supporting the magnetic induction coils to approach each other under external force and to restore the distance between them after the external force disappears; and pressure sensing parameters are obtained by detecting changes in the inductance of the magnetic induction coils.

[0006] In some alternative embodiments, the mutual inductance tactile sensing unit further includes a second insulating layer covering the outer surfaces of the two outermost magnetic coils.

[0007] In some alternative embodiments, the mutual inductance tactile sensing unit further includes: a soft magnetic foil layer covering the outer surface of the second insulating layer, and a third insulating layer covering the outer surface of the soft magnetic foil layer.

[0008] In some alternative embodiments, the soft magnetic foil layer is a permalloy foil or a nanocrystalline foil.

[0009] In some alternative embodiments, adjacent magnetic coils are connected in sequence, with the two outermost magnetic coils leading out as detection terminals; contact sensing parameters are obtained by detecting changes in the overall inductance and / or overall resistance of the magnetic coils.

[0010] In some alternative embodiments, at least one set of the magnetic coils are connected through a metallized hole penetrating the first insulating layer therebetween; and / or, at least one set of the magnetic coils are connected by leads to the outside of the magnetic coils.

[0011] In some alternative embodiments, the structure in which the adjacent magnetic coils are connected through a metallized hole penetrating the first insulating layer includes: a first printed magnetic coil formed on a first surface of the first insulating layer, and a second printed magnetic coil formed on a second surface of the first insulating layer opposite to the first surface; the inner ends of the first printed magnetic coil and the second printed magnetic coil are connected through the metallized hole.

[0012] In some alternative embodiments, the magnetic induction coil is a thermistor magnetic induction coil formed of a thermistor conductive material, and temperature sensing parameters are obtained by detecting the resistance change of the thermistor magnetic induction coil.

[0013] In some alternative embodiments, the second insulating layer and the third insulating layer are flexible inelastic insulating layers; and / or, only one of the first insulating layers is an elastic insulating layer.

[0014] Another object of the present invention is to provide a mutual inductance tactile sensor to solve the problems in the prior art.

[0015] In some illustrative embodiments, the mutual inductance tactile sensor includes: the mutual inductance tactile sensing unit described in any one of the above, and a signal detector; the signal detector is connected to the magnetic coil of the mutual inductance tactile sensing unit to obtain pressure sensing parameters by detecting changes in the inductance of the magnetic coil.

[0016] Compared with the prior art, this application has the following advantages:

[0017] This application adopts a mutual inductance multi-coil design, which has the advantages of high sensitivity and low requirements for the surrounding environment compared with the eddy current induction principle in the prior art, and the detection results are efficient and reliable. Attached Figure Description

[0018] Figure 1 This is a structural example of the mutual inductance tactile sensing unit in the embodiments of the present invention;

[0019] Figure 2 This is a second example of the structure of the mutual inductance tactile sensing unit in the embodiments of the present invention;

[0020] Figure 3 This is a third example of the structure of the mutual inductance tactile sensing unit in the embodiments of the present invention;

[0021] Figure 4This is the fourth example of the structure of the mutual inductance tactile sensing unit in the embodiments of the present invention;

[0022] Figure 5 This is the fifth example of the structure of the mutual inductance tactile sensing unit in the embodiments of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that, where there is no conflict, the various technical features in the embodiments of the present invention can be combined with each other.

[0025] This invention discloses a mutual inductance tactile sensing unit, specifically, as follows: Figure 1-5 As shown, Figure 1 This is a structural example of the mutual inductance tactile sensing unit in the embodiments of the present invention; Figure 2 This is a second example of the structure of the mutual inductance tactile sensing unit in the embodiments of the present invention; Figure 3 This is a third example of the structure of the mutual inductance tactile sensing unit in the embodiments of the present invention; Figure 4 This is a fourth example of the structure of the mutual inductance tactile sensing unit in this embodiment of the invention (exploded view of the structure). Figure 5 This is a fifth example of the structure of the mutual inductance tactile sensing unit in this embodiment of the invention (exploded view); the mutual inductance tactile sensing unit includes: at least two magnetic induction coils 10 stacked together, with a first insulating layer 20 for electrical isolation between each pair of adjacent magnetic induction coils 10; at least one of the first insulating layers 20 is an elastic insulating layer formed of one or more layers of elastomer (such as 20a, 20b), to support the magnetic induction coils 10 to approach each other under the action of external force, and to restore the distance between them after the external force disappears; pressure sensing parameters are obtained by detecting the change in inductance of the magnetic induction coils.

[0026] In use, the detection end of the mutual inductance tactile sensing unit is connected to a signal detection device. When the mutual inductance tactile sensing unit is subjected to an external force, the external force will drive the elastic insulating layer to contract inward, thereby reducing the distance between the magnetic coils and causing a change in the inductance of the magnetic coils. This inductance value or inductance change value can be converted into a corresponding pressure sensing parameter to provide feedback on the force applied to the mutual inductance tactile sensing unit. After the external force disappears, the elastic insulating layer will naturally return to its initial state (i.e., the initial spacing of the magnetic coils) under the drive of its own elastic potential energy.

[0027] In some embodiments, for the inductance detection and conversion of multiple magnetic induction coils, each magnetic induction coil can be detected independently, and then the coupling coefficient between the multiple magnetic induction coils can be calculated. The pressure sensing parameters can then be obtained by using the linear relationship between the coupling coefficient and the pressure. In other embodiments, the multiple magnetic induction coils can also be detected as a whole (based on the series connection structure of multiple magnetic induction coils), and the pressure sensing parameters can then be obtained by using the linear relationship between the overall inductance value and the pressure.

[0028] This application adopts a mutual inductance multi-coil design, which has the advantages of high sensitivity and low requirements for the surrounding environment compared with the eddy current induction principle in the prior art, and the detection results are efficient and reliable.

[0029] like Figure 3 As shown, in some embodiments, the multiple magnetic coils 10 in the present invention can be directly encapsulated inside an elastic body, ensuring that there is an elastic body (i.e., an elastic insulating layer) with a certain distance between the magnetic coils.

[0030] In some embodiments of the present invention, the magnetic induction coil can be a thermistor magnetic induction coil formed of a thermistor conductive material. Temperature sensing parameters are obtained by detecting changes in the resistance of the thermistor magnetic induction coil. In this embodiment, changes in the inductance and resistance of the magnetic induction coil can be detected simultaneously to obtain pressure sensing parameters and temperature sensing parameters, achieving multimodal detection.

[0031] In some embodiments of the present invention, at least one of the first insulating layers 20 is an elastic insulating layer formed of one or more layers of elastomer (e.g., 20a, 20b, 9), while the other first insulating layers 20 can be flexible inelastic insulating layers formed of flexible inelastic materials (e.g., 1, 5). Since inelastic insulating layers have almost no shrinkage deformation properties, when subjected to external forces, the external forces can be transferred to the elastic insulating layers as much as possible, thereby further improving the detection sensitivity based on the mutual inductance multi-coil sensing. In other embodiments, the other first insulating layers can also be elastic insulating layers formed of one or more layers of elastomer, but the detection sensitivity may be reduced compared to the structure of a single elastic insulating layer. In still other embodiments, the first insulating layer can be made of a rigid material.

[0032] The elastomers in the embodiments of the present invention include, but are not limited to, polymeric elastomers such as silicone and TPU, and the flexible non-elastic materials in the embodiments of the present invention include, but are not limited to, flexible substrates such as PI and PET. Preferably, the thickness of the elastic insulating layer in the embodiments of the present invention is 1-6 mm, and the thickness of the flexible non-elastic insulating layer is 25-100 μm.

[0033] In some embodiments, the mutual inductance tactile sensing unit of the present invention may further include a second insulating layer (such as 10, 11) covering the outer surfaces of the two outermost magnetic induction coils. The second insulating layer in this embodiment serves to isolate the magnetic induction coils from direct exposure to air, providing one or more functions such as oxygen barrier, waterproofing, and electrical isolation. Its material can be an elastic insulating layer formed of one or more layers of elastomer, a flexible non-elastic insulating layer formed of a flexible non-elastic material, or a rigid structure; preferably, the second insulating layer is a flexible non-elastic insulating layer.

[0034] In some embodiments, the mutual inductance tactile sensing unit of the present invention further includes: a soft magnetic foil layer (such as 12, 13) covering the outer surface of the second insulating layer, and a third insulating layer (such as 14, 15) covering the outer surface of the soft magnetic foil layer. In this embodiment, the soft magnetic foil layer serves as an electromagnetic shielding layer for the multi-coil magnetic field, thereby further improving the anti-interference performance of the detection based on the mutual inductance multi-coil sensing. Preferably, the soft magnetic foil layer is a permalloy foil or a nanocrystalline foil.

[0035] Furthermore, the upper and lower soft magnetic foil layers are respectively designed with a "cap" structure to enclose the multiple coils inside as much as possible, leaving only the opening for the detection end.

[0036] Furthermore, when the mutual inductance tactile sensing unit simultaneously detects temperature sensing parameters, the soft magnetic foil layer, as a metallic material, has excellent thermal conductivity, which is beneficial for the inward conduction of surface temperature, thereby improving the response efficiency of temperature detection.

[0037] Preferably, the thickness of the soft magnetic foil layer in the embodiments of the present invention is 5 to 25 μm.

[0038] In this embodiment of the invention, the third insulating layer serves to prevent the soft magnetic foil layer from being directly exposed to the air, thus providing one or more functions such as oxygen barrier and waterproofing. Its material can be an elastic insulating layer formed by one or more layers of elastomer, a flexible non-elastic insulating layer formed by a flexible non-elastic material, or a rigid structure. Preferably, the second insulating layer is a flexible non-elastic insulating layer.

[0039] In some embodiments of the present invention, adjacent magnetic coils are connected sequentially, with the two outermost magnetic coils leading out as detection terminals; contact sensing parameters are obtained by detecting changes in the overall inductance and / or overall resistance of the magnetic coils. In this embodiment, multiple magnetic coils are connected in series into a single structure, thus a single signal detection device can be used to acquire the inductance values ​​or changes in inductance values ​​of multiple magnetic coils.

[0040] In some embodiments, at least one set of adjacent magnetic coils are connected through a metallized hole penetrating the first insulating layer therebetween; and / or, at least one set of adjacent magnetic coils are connected by leads extending to the outside of the magnetic coils.

[0041] The use of metallized holes penetrating the first insulating layer to connect adjacent magnetic coils greatly simplifies the wiring design of the magnetic coils. Similarly, connecting adjacent magnetic coils to the outside of the magnetic coils also simplifies the wiring design, thereby improving production efficiency and reducing production costs. In addition, the metallized holes connecting adjacent magnetic coils effectively combine two coils into one. Therefore, based on this structure, the horizontal dimensions of the product can be greatly reduced by adding a very small vertical height (i.e., thickness), which is beneficial for product miniaturization.

[0042] In some embodiments of the present invention, the structure in which adjacent magnetic coils are connected through a metallized hole penetrating a first insulating layer includes: a first printed magnetic coil formed on a first surface of the first insulating layer, and a second printed magnetic coil formed on a second surface of the first insulating layer opposite to the first surface; the inner ends of the first printed magnetic coil and the second printed magnetic coil are connected through the metallized hole.

[0043] In this embodiment, the printed magnetic coil can be directly formed using conductive paste through additive manufacturing methods such as printing or lithography, further improving production efficiency and reducing costs. In other embodiments, the magnetic coil can also be formed using other materials and processes; there are no restrictions on this.

[0044] The thickness of the magnetic induction coil in this embodiment of the invention is 10-100 μm.

[0045] The magnetic coils in the embodiments of the present invention are not limited to planar coil structures or three-dimensional coil structures.

[0046] This invention also discloses a mutual inductance tactile sensor, comprising: a mutual inductance tactile sensing unit as described above, and a signal detector; the signal detector is connected to the magnetic coil of the mutual inductance tactile sensing unit, and is used to obtain pressure sensing parameters by detecting changes in the inductance of the magnetic coil.

[0047] In cases where the magnetic induction coil is formed using a thermistor-conductive material, the signal detector can also be used to detect changes in the resistance of the magnetic induction coil and obtain temperature sensing parameters.

[0048] The signal detector can be any of the existing inductance detection instruments, or an RLC detector that can measure multiple electrical signals.

[0049] Example 1

[0050] like Figure 3 As shown, this embodiment of the invention also discloses a mutual inductance tactile sensing unit, comprising: a first magnetic induction coil and a second magnetic induction coil formed by winding a metal wire (such as a copper wire) to form a stack, the first magnetic induction coil and the second magnetic induction coil being encapsulated in an elastic body, with both ends led out as detection terminals.

[0051] Example 2

[0052] like Figure 4 As shown, this embodiment of the invention also discloses a mutual inductance tactile sensing unit, comprising:

[0053] First PI film 1;

[0054] A first printed magnetic coil 2 is formed on the first surface of the first PI film 1, and a second printed magnetic coil 3 is formed on the second surface of the first PI film 1; the inner ends of the first printed magnetic coil 2 and the second printed magnetic coil 3 are connected through a first metallized hole 4 penetrating the first PI film 1.

[0055] Second PI film 5;

[0056] A third printed magnetic coil 6 is formed on the first surface of the second PI film 5, and a fourth printed magnetic coil 7 is formed on the second surface of the second PI film 5; the inner ends of the third printed magnetic coil 6 and the fourth printed magnetic coil 7 are connected through a second metallized hole 8 penetrating the second PI film 5.

[0057] The outer ends of the second printed magnetic coil 3 and the third printed magnetic coil 6 are connected to the outside of the coil, and the outer ends of the first printed magnetic coil 2 and the fourth printed magnetic coil 7 are connected to the outside of the coil as detection terminals.

[0058] A TPU elastic pad 9 is provided between the second printed magnetic coil 3 and the third printed magnetic coil 6.

[0059] Example 3

[0060] like Figure 5 As shown, Example 3, based on Example 2, further includes:

[0061] A third PI film 10 covering the first printed magnetic coil 2, and a fourth PI film 11 covering the fourth printed magnetic coil 7; a first soft magnetic foil 12 disposed on the third PI film 10, and a second soft magnetic foil 13 disposed on the fourth PI film 11; a fifth PI film 14 covering the first soft magnetic foil 12, and a sixth PI film 15 covering the second soft magnetic foil 13.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mutual inductance tactile sensing unit, characterized in that, include: At least two magnetic induction coils are stacked, and a first insulating layer is provided between each two adjacent magnetic induction coils for electrical isolation between the magnetic induction coils; At least one of the first insulating layers is an elastic insulating layer formed by one or more layers of elastomer, used to support the magnetic coils to approach each other under the action of external force, and to restore the distance between them after the external force disappears; Pressure sensing parameters are obtained by detecting changes in the inductance of the magnetic coil.

2. The mutual inductance tactile sensing unit according to claim 1, characterized in that, Also includes: A second insulating layer covering the outer surfaces of the two outermost magnetic coils.

3. The mutual inductance tactile sensing unit according to claim 2, characterized in that, Also includes: A soft magnetic foil layer covering the outer surface of the second insulating layer, and a third insulating layer covering the outer surface of the soft magnetic foil layer.

4. The mutual inductance tactile sensing unit according to claim 3, characterized in that, The soft magnetic foil layer is a permalloy foil or a nanocrystalline foil.

5. The mutual inductance tactile sensing unit according to claim 1, characterized in that, The adjacent magnetic coils are connected in sequence, and the two outermost magnetic coils are led out as detection terminals; Pressure sensing parameters are obtained by detecting changes in the overall inductance of the magnetic coil.

6. The mutual inductance tactile sensing unit according to claim 1 or 5, characterized in that, At least one set of the magnetic coils are connected through a metallized hole penetrating the first insulating layer therebetween; and / or, at least one set of the magnetic coils are connected by leads extending to the outside of the magnetic coils.

7. The mutual inductance tactile sensing unit according to claim 6, characterized in that, The structure in which adjacent magnetic coils are connected through a metallized hole penetrating the first insulating layer therebetween includes: A first printed magnetic coil is formed on the first surface of the first insulating layer, and a second printed magnetic coil is formed on the second surface of the first insulating layer opposite to the first surface; The inner ends of the first printed magnetic coil and the second printed magnetic coil are connected through the metallized hole.

8. The mutual inductance tactile sensing unit according to claim 1, characterized in that, The magnetic induction coil is a thermistor magnetic induction coil formed of a thermistor conductive material. Temperature sensing parameters are obtained by detecting the resistance change of the thermistor magnetic induction coil.

9. The mutual inductance tactile sensing unit according to claim 3, characterized in that, The second insulating layer and the third insulating layer are flexible inelastic insulating layers; and / or, only one of the first insulating layers is an elastic insulating layer.

10. A mutual inductance tactile sensor, characterized in that, include: The mutual inductance tactile sensing unit and signal detection device as described in any one of claims 1-9; The signal detection device is connected to the magnetic coil of the mutual inductance tactile sensing unit to obtain pressure sensing parameters by detecting changes in the inductance of the magnetic coil.

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