Micro-cantilever tactile sensor and preparation method thereof

Abstract

The application relates to a micro-cantilever tactile sensor and a preparation method thereof, which comprises a base, an upper surface of the base is upwardly convex to form a crumpled structure, a cross section of the crumpled structure is first reduced and then increased from top to bottom along an axial direction of the crumpled structure; the base is provided with a plurality of grooves along a circumferential direction of the crumpled structure, the groove comprises a groove body and a groove connecting part extending from the groove body to a top end of the crumpled structure; a sensing element is filled in the plurality of grooves; a touch rod is coaxially connected to the top end of the crumpled structure, and the elastic modulus of the touch rod is greater than that of the base. In the detection process, the application can deflect instead of bending, efficiently convert a stress signal into an electric signal, provide a more obvious electric signal for an external circuit, has the characteristics of low detection threshold, high precision, high response speed, low cost and small size.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sensor technology, in particular to a micro-cantilever tactile sensor and a preparation method thereof. BACKGROUND

[0002] The tactile sensor can infer the basic characteristics of an object and realize feedback through pressure, vibration, position and other tactile information. However, the tactile sensor in the prior art cannot meet the design requirements of high precision, high response speed, low cost and miniaturization. SUMMARY

[0003] Therefore, the technical problem to be solved by the present application is to overcome the problem that the prior art cannot meet the design requirements of high precision, high response speed, low cost and miniaturization.

[0004] To solve the above technical problems, on the one hand, the present application provides a micro-cantilever tactile sensor, comprising:

[0005] a base, the upper surface of the base is upwardly convex to form a crumpled structure, the cross section of the crumpled structure decreases first and then increases along the axial direction of the crumpled structure; the base is provided with a plurality of grooves around the crumpled structure along the circumferential direction thereof, the groove comprises a groove body and a groove connecting portion extending from the groove body to the top end of the crumpled structure;

[0006] a sensing element filled in the plurality of grooves;

[0007] a touch rod coaxially connected to the top end of the crumpled structure, the elastic modulus of the touch rod is greater than the elastic modulus of the base.

[0008] In an embodiment of the present application, the elastic modulus of the touch rod is 100 times the elastic modulus of the base.

[0009] In an embodiment of the present application, along the axial direction of the touch rod, the size of the base is smaller than the size of the touch rod.

[0010] In an embodiment of the present application, along the axial direction of the touch rod, the ratio of the size of the base to the size of the touch rod is greater than 1:5.

[0011] In an embodiment of the present application, the plurality of grooves are equally divided and arranged on the base along the circumferential direction of the crumpled structure.

[0012] In an embodiment of the present application, the touch rod and the base are fixed by adhesive.

[0013] In an embodiment of the present application, the base is made of one of polydimethylsiloxane, epoxy resin and rubber.

[0014] In an embodiment of the present application, the sensing material comprises polydimethylsiloxane, nickel powder, GaIn alloy and silver ion conductive ink.

[0015] In one embodiment of the application, the touch rod is one of a conical shape, a cylindrical shape.

[0016] In another aspect, the application provides a method for manufacturing a micro-cantilever tactile sensor, comprising:

[0017] filling a base material in a mold and curing the base material to form a base;

[0018] filling a sensing material in the plurality of grooves and curing the sensing material to form a sensing element;

[0019] removing the excess material from the base to form a connecting portion of the touch rod.

[0020] The above technical solutions of the application have the following advantages over the prior art:

[0021] The micro-cantilever tactile sensor and the method for manufacturing the same have the following advantages: the elastic modulus of the touch rod is greater than that of the base, so that the sensing element can have a greater strain after a load is applied; in addition, the base is provided with a crumpled structure, and stress is concentrated at the crumpled portion, so that the base deflects rather than bends during detection, and the stress signal is efficiently converted into an electrical signal, which can provide a more obvious electrical signal for an external circuit, has a low detection threshold, high precision, high response speed, low cost, and can be miniaturized. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to make the content of the application more easily understood, the application will be further described in detail below according to specific embodiments of the application and in conjunction with the drawings, in which

[0023] Figure 1 is a structural schematic diagram of a micro-cantilever tactile sensor in a preferred embodiment of the application;

[0024] Figure 2 is a schematic diagram of curing and forming the base in the application;

[0025] Figure 3 is a schematic diagram of filling the sensing material in the base in the application;

[0026] Figure 4 is a schematic diagram of the sensing element after being fixed and formed in the application;

[0027] Figure 5 is a simulation schematic of embodiments 1-2 and the application Figure 1 ;

[0028] Figure 6 is a simulation schematic of embodiments 1-2 and the application Figure 2 ;

[0029] Figure 7 is a flow chart of a micro-cantilever tactile sensor preparation method.

[0030] Description of the drawings: 100, base; 110, crumpled structure; 120, groove; 121, groove body; 122, groove connecting part;

[0031] 200, sensing element;

[0032] 300, touch rod;

[0033] 400, material removal part. DETAILED DESCRIPTION

[0034] The application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the application and implement it, but the embodiments are not limiting the application.

[0035] Referring to Figures 1-4 The application provides a micro-cantilever tactile sensor, comprising:

[0036] The base 100 has an upper surface that is upwardly convex to form a crumpled structure 110, and the cross section of the crumpled structure 110 decreases first and then increases along the axis direction of the crumpled structure 110 from top to bottom. In some embodiments, the longitudinal section of the crumpled structure 110 can be a hyperbola. The base 100 is provided with a plurality of grooves 120 around the crumpled structure 110 along the circumferential direction thereof, and the groove 120 comprises a groove body 121 and a groove connecting part 122 extending from the groove body 121 to the top end of the crumpled structure 110;

[0037] The sensing element 200 is filled in the plurality of grooves 120;

[0038] The touch rod 300 is coaxially connected to the top end of the crumpled structure 110, and the elastic modulus of the touch rod 300 is greater than that of the base 100. In some embodiments, the touch rod 300 can be processed by 3D printing, laser processing, etc. The material of the touch rod 300 can also be selected from tungsten steel, cobalt-molybdenum alloy, stainless steel, etc. hard alloy, as long as the base 100 and the touch rod 300 are not deflected without load after being adhered.

[0039] The elastic modulus of the touch rod 300 is 100 times that of the base 100.

[0040] Referring to Figures 5-6Comparative Example 1 adopts a homogeneous rod of soft material (smaller elastic modulus), and Comparative Example 2 adopts a homogeneous rod of hard material (larger elastic modulus). The present application adopts a heterogeneous rod with the upper part being hard and the lower part being soft. The same load is applied to Examples 1-2 and the present application for simulation, and the following conclusions are drawn Figure 5 and Figure 6 In the above, the left view is Comparative Example 1, the middle view is Comparative Example 2, and the right view is the present application.

[0041] Compared with Comparative Example 2, Examples 1 and the present application with the base of soft material have a larger strain value, and under the same conditions, a larger strain represents a more obvious signal output. Compared with Comparative Example 1, the deflection of the present application is smaller, and thus the response is faster. In summary, the design of the rod being rigid and the base being soft in the present application can improve the response speed while maintaining high precision.

[0042] Specifically, the elastic modulus of the touch rod 300 in the present application is greater than the elastic modulus of the base 100, so that after the load is applied, the sensing element 200 can have a larger strain. In addition, the present application is provided with a crumpling structure 110 on the base, and there is a stress concentration effect at the crumpling part, so that the present application can deflect rather than bend during detection, and the stress signal can be efficiently converted into an electrical signal, which can provide a more obvious electrical signal for the external circuit, has the characteristics of low detection threshold, high precision, high response speed, low cost, and can realize miniaturization.

[0043] In some embodiments, the thickness of the base 100 can be set to 3-10 mm. Alternatively, the thickness of the base 100 can be set to 6 mm. It should be noted that the thickness of the base 100 cannot be too thin, so as to facilitate filling of the sensing material at the groove 120 and arranging the electrode at the sensing material to be connected to the external circuit.

[0044] Further, along the axial direction of the touch rod 300, the size of the base 100 is smaller than the size of the touch rod 300. Along the axial direction of the touch rod 300, the ratio of the size of the base 100 to the size of the touch rod 300 is greater than 1:5.

[0045] Specifically, the length of the touch rod 300 is also much longer than the length of the base 100, so that during tactile force detection, the relatively hard touch rod 300 will only deflect by a certain angle, and the touch rod 300 itself will not deform, and the part of the entire micro-cantilever beam tactile sensor that bends is only the base 100. Therefore, under the same tactile force, the present application can make the strain of the sensing element 200 larger and have a larger resistance change rate.

[0046] A plurality of grooves 120 are arranged on the base 100 along the circumference of the crumpled structure 110. In some embodiments, the number of grooves 120 can be 8-12. In particular, the plurality of grooves 120 in the present embodiment are evenly arranged along the circumference, so that the sensor can sense the tactile force in any direction, and the direction of the applied tactile force can be determined according to the resistance change rate of the material in different directions. Of course, the grooves 120 on the base 100 can be arranged in any form to meet the detection requirements.

[0047] The touch rod 300 is fixedly connected to the base 100 by glue. For example, the touch rod 300 and the base 100 can be connected by one of 502 glue, 101 glue, and AB glue.

[0048] The base 100 is made of one of polydimethylsiloxane, epoxy resin, and rubber. In particular, the material used in the present embodiment facilitates the removal of the material to form the grooves 120. In other embodiments, the material of the base 100 can also be other materials as long as it is convenient to remove. The curing method of the base 100 should be determined according to the material selected for the base 100. For example, when the material of the base 100 is polydimethylsiloxane, the base 100 material can be filled in a mold, and heated at 90-110°C and 50-100Kpa for 4 hours to cure. The polydimethylsiloxane can also be naturally cured at room temperature for 8-10 hours. When the material of the base 100 is rubber, it is heated at 100-150°C for 1-3 hours to cure and form.

[0049] The sensing material includes polydimethylsiloxane, nickel powder, GaIn alloy, and silver ion conductive ink. In some other embodiments, the sensing material can also select other piezoresistive materials. After the polydimethylsiloxane, nickel powder, GaIn alloy, and silver ion conductive ink are thoroughly mixed, they are stirred for 10-15 minutes and filled and coated at the grooves 120 of the base 100. After being heated at 90-110°C and 50-100Kpa for 4 hours, the sensing material is cured and formed. Of course, the sensing material can select other piezoresistive materials.

[0050] The touch rod 300 is one of a circular cone and a circular cylinder. The circular cylinder has good stability. The circular cone has less material and good stability. The touch rod 300 should be made of a material that is light in weight and high in hardness.

[0051] Referring to Figure 7 In another aspect, the present application provides a preparation method of a micro-cantilever tactile sensor, comprising:

[0052] Step S100: filling the base 100 material in a mold, and curing and forming the base 100 after the base 100 material is cured and formed;

[0053] Step S200: filling the inductive material in the plurality of grooves 120, and solidifying to form the inductive element 200; the inductive element 200 is formed by solidifying after connecting the inductive material with the electrode.

[0054] Step S300: removing the excess material removal portion 400 on the base 100, and connecting the contact rod 300 on the top of the crimp structure 110 in the base 100.

[0055] Obviously, the above embodiments are only examples for clearly illustrating, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, it is not necessary and also impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the invention.

Claims

1. A microcantilever tactile sensor characterized by: The application relates to a touch rod, which comprises the following parts: a base, the upper surface of the base is upwardly convex to form a crumpled structure, the cross section of the crumpled structure is first reduced and then increased along the axial direction of the crumpled structure; a plurality of grooves are arranged on the base around the crumpled structure in the circumferential direction of the crumpled structure, the grooves comprise groove bodies and groove connecting parts extending from the groove bodies to the top end of the crumpled structure; an inductive element filled in the plurality of grooves; an inductive material is filled in the plurality of grooves and is cured and formed into an inductive element; the inductive material comprises polydimethylsiloxane, nickel powder, GaIn alloy and silver ion conductive ink; a touch rod coaxially connected to the top end of the crumpled structure, the elastic modulus of the touch rod is greater than the elastic modulus of the base; the elastic modulus of the touch rod is 100 times the elastic modulus of the base; along the axial direction of the touch rod, the size ratio of the base to the touch rod is greater than 1:5; the material of the touch rod is selected from hard alloy.

2. The microcantilever tactile sensor according to claim 1, wherein: Along the axial direction of the touch rod, the size of the base is smaller than the size of the touch rod.

3. The microcantilever tactile sensor of claim 1, wherein: The plurality of grooves are equally arranged on the base along the circumferential direction of the crumpled structure.

4. The microcantilever tactile sensor of claim 1, wherein: The touch rod and the base are fixed by adhesive.

5. The microcantilever tactile sensor of claim 1, wherein: The base is made of one of polydimethylsiloxane, epoxy resin and rubber.

6. The microcantilever tactile sensor of claim 1, wherein: The touch rod is one of a conical shape and a cylindrical shape.

7. The method of claim 1, wherein: The application further relates to a manufacturing method of the touch rod, which comprises the following steps: filling a base material in a mold and curing and forming the base material to form a base; filling an inductive material in a plurality of grooves and curing and forming the inductive material into an inductive element; removing the excess material on the base and connecting a touch rod to the top of the crumpled structure in the base.

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