A flexible strain sensor with three-dimensional spatial recognition capability

Abstract

The present invention relates to a flexible strain sensor with spatial three-dimensional recognition capability, comprising an insulating sheath and a flexible body, wherein the flexible body is located inside the insulating sheath; wherein the flexible body comprises a flexible insulating shaft, and a plurality of electrode layers are sequentially connected to the flexible insulating shaft along the axial direction of the flexible insulating shaft, a flexible conductive substrate is filled between two adjacent electrode layers, and each electrode layer comprises a plurality of circumferentially arranged electrode sheets, and an insulating spacer is connected between two adjacent electrode sheets. The present invention can effectively identify not only the strain size but also the strain direction, and has good spatial three-dimensional recognition capability; it does not depend on the body shape or wearing position of the specific wearer, and has the characteristics of strong compatibility.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a flexible strain sensor with spatial three-dimensional recognition capability. Background Art

[0002] Motion capture is a technology that uses optical tracking, image analysis, mechanical or inertial sensors to collect information such as gestures, facial expressions, body movements, and movement patterns of people or animals. It has a wide range of applications in animation, film and television, game production, human-computer interaction, VR games, and other fields. However, current motion capture equipment and technology are still at the stage of enterprise-level applications or large-scale experience interactive equipment, and cannot meet the application level of personal electronic consumer products. For example, optical motion capture requires the coordination of multiple cameras, and the amount of data that needs to be processed is huge, and the system is expensive, which is not suitable as a personal electronic consumer product; image analysis is currently still at the stage of two-dimensional contour recognition, and it is difficult to recognize complex three-dimensional motion patterns; mechanical motion capture equipment has great obstacles and restrictions on the user's movements, and is not comfortable to wear; inertial sensors are suitable for recognizing large-scale and high-speed body movements, but have great limitations in recognizing fine and slow movements of the hands.

[0003] The motion capture system based on flexible strain sensors has the advantages of high precision, high response speed, light weight, etc., and is easy to integrate with clothing, gloves, etc. It is the main development direction of the next generation of wearable motion capture devices and has broad application prospects in the fields of virtual social interaction, metaverse, VR games, etc. The function of the strain sensor is to convert the deformation signal of the sensor under the action of external force into an electrical signal. According to the working mechanism, flexible strain sensors can be mainly divided into resistive and capacitive types. Among them, resistive strain sensors usually use flexible matrix materials to load conductive nanomaterials to form a two-dimensional or three-dimensional conductive network. When the conductive network is deformed under the action of the outside world, the contact between the conductive nanomaterials changes, thereby causing resistance changes. The working mechanism of the capacitive strain sensor is based on the change in device capacitance caused by factors such as electrode spacing, electrode effective area, and dielectric material volume changes caused by strain.

[0004] Therefore, existing strain sensors all detect the strain magnitude based on the change in resistance or capacitance caused by strain. When used to detect the movement of human joints, it is necessary to calculate the joint bending angle based on the curvature radius of the worn joint. Therefore, there are still the following problems in the application of motion capture: First, the existing strain sensors are generally symmetrical structures, which can identify the strain magnitude but cannot identify the specific bending direction - the strain direction (such as Figure 1As shown in the figure, it is difficult to identify the complex three-dimensional spatial motion patterns of the human body; secondly, different joints of the human body have different curvature radii, and different people have different body shapes and joint sizes. Different joint specifications require customized corresponding strain sensors. Existing strain sensors are difficult to apply to the production of standardized consumer electronic products and have poor compatibility. They have very large limitations in the promotion and application of motion capture.

[0005] In summary, the existing flexible strain sensors cannot identify the specific strain direction and have poor compatibility, are not easy to promote and apply, and cannot meet usage requirements. Summary of the invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the defects of the flexible strain sensor in the prior art that it cannot identify the specific strain direction and has poor compatibility.

[0007] In order to solve the above technical problems, the present invention provides a flexible strain sensor with spatial three-dimensional recognition capability, comprising:

[0008] Insulating sheath;

[0009] A flexible body, the flexible body being located inside the insulating sheath;

[0010] Among them, the flexible body includes a flexible insulating shaft, on which multiple electrode layers are connected in sequence along the axial direction of the flexible insulating shaft, a flexible conductive substrate is filled between two adjacent electrode layers, each electrode layer includes multiple circumferentially arranged electrode sheets, and an insulating spacer is connected between two adjacent electrode sheets.

[0011] In one embodiment of the present invention, each of the electrode layers is ring-shaped, a mounting hole is formed in the middle of the electrode layer, and the flexible insulating shaft is connected to the mounting hole.

[0012] In one embodiment of the present invention, the intervals between two adjacent electrode layers are equal.

[0013] In one embodiment of the present invention, all the electrode sheets in each electrode layer are evenly distributed in the circumferential direction.

[0014] In one embodiment of the present invention, the insulating sheath is coated on the outside of the flexible body.

[0015] In one embodiment of the present invention, the insulating sheath is a fabric fiber layer.

[0016] In one embodiment of the present invention, the flexible insulating shaft is made of a rubber member.

[0017] In one embodiment of the present invention, the flexible conductive substrate is made of a nano-conductive composite material.

[0018] In one embodiment of the present invention, each of the electrode layers includes at least three electrode sheets.

[0019] In one embodiment of the present invention, each of the electrode layers comprises an insulating substrate, a surface of the insulating substrate is plated with metal electrode regions in different regions, the metal electrode regions form the electrode sheets, and an insulating spacer between two adjacent electrode sheets forms the insulating spacer.

[0020] The above technical solution of the present invention has the following advantages compared with the prior art:

[0021] The flexible strain sensor described in the present invention can not only effectively identify the strain size but also effectively identify the strain direction, and has good spatial three-dimensional recognition ability; it is independent of the body shape or wearing part of the specific wearer, has the characteristics of strong compatibility, and can be well applied to the application and promotion of wearable motion capture devices in various scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0023] Figure 1 It is a schematic diagram of bending of a symmetrical thin-layer strain sensor in different directions in the prior art;

[0024] Figure 2 It is a schematic diagram of the structure of a flexible strain sensor with spatial three-dimensional recognition capability of the present invention;

[0025] Figure 3 yes Figure 2 Schematic diagram of the structure of the flexible body without deformation (removing the flexible conductive substrate);

[0026] Figure 4 yes Figure 2 Schematic diagram of the structure when the flexible body is deformed (the flexible conductive substrate is removed);

[0027] Figure 5 It is a schematic diagram of the structure of the electrode layer in the present invention;

[0028] Explanation of the reference numerals in the specification: 1. insulating sheath; 2. flexible main body; 21. flexible insulating shaft; 22. electrode layer; 221. electrode sheet; 222. insulating spacer; 223. mounting hole; 23. flexible conductive substrate. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0030] Reference Figure 2-Figure 3 As shown, this embodiment discloses a flexible strain sensor with spatial three-dimensional recognition capability, including an insulating sheath 1 and a flexible body 2,

[0031] The flexible body 2 is located inside the insulating sheath 1, so that the insulating sheath 1 protects the flexible body 2;

[0032] The flexible body 2 includes a flexible insulating shaft 21, and a plurality of electrode layers 22 are sequentially connected to the flexible insulating shaft 21 along the axis direction of the flexible insulating shaft 21, and a flexible conductive substrate 23 is filled between two adjacent electrode layers 22;

[0033] like Figure 5 As shown, each electrode layer 22 includes a plurality of circumferentially arranged electrode sheets 221, and an insulating spacer 222 is connected between two adjacent electrode sheets 221, so that the plurality of electrode sheets 221 in each electrode layer 22 are independent of each other and insulated from each other.

[0034] The strain sensor is a flexible multi-section structure. When the strain sensor is working, the change in the distance between the electrode layers 22 will cause the resistance to change. Figure 4 As shown, the spacing between the electrode layers 22 on one side of the flexible insulating shaft 21 increases and the flexible conductive substrate 23 between the electrode layers 22 is compressed, and the resistance decreases; while the spacing between the electrode layers 22 on the other side increases and the flexible conductive substrate 23 between the electrode layers 22 is stretched, and the resistance increases. Since the electrode sheets 221 in different directions in each electrode layer 22 are independent of each other, the bending direction and bending degree of the flexible body 2 can be identified by measuring the resistance changes between the multiple electrode sheets 221 between different layers, that is, the strain direction and strain degree can be identified, thereby achieving the purpose of motion capture.

[0035] The above-mentioned strain sensor utilizes an asymmetric multi-section structure to give the strain sensor spatial three-dimensional recognition capability. The overall structure has the characteristics of high integration and flexibility. By adopting a partitioned electrode sheet 221 structure, the spatial recognition capability of the sensor is more effectively enhanced, and it can more accurately identify the bending direction and degree of human joints, thereby realizing accurate capture of human movements, and has good compatibility with different joints of the human body.

[0036] In one embodiment, each electrode layer 22 is annular, a mounting hole 223 is formed in the middle of the electrode layer 22, and the flexible insulating shaft 21 is connected to the mounting hole 223. Further, to ensure installation reliability, the flexible insulating shaft 21 can be embedded in the mounting hole 223.

[0037] In one embodiment, the intervals between two adjacent electrode layers 22 are equal.

[0038] In one embodiment, all electrode sheets 221 in each electrode layer 22 are evenly distributed in the circumferential direction to better ensure the bending flexibility of the flexible body 2 .

[0039] For example, each electrode layer 22 has three electrode sheets 221 , and the three electrode sheets 221 are evenly arranged circumferentially around the flexible insulating shaft 21 , so as to better identify a variety of different bending directions.

[0040] The insulating sheath 1 is a flexible member and can bend along with the bending of the flexible body 2 .

[0041] In one of the embodiments, the insulating sheath 1 is wrapped around the outside of the flexible body 2, which can not only protect the flexible body 2 well, but also make it easier to ensure the convenience and reliability of the connection between the insulating sheath 1 and the flexible body 2.

[0042] Furthermore, the insulating sheath 1 is made of a fabric fiber layer.

[0043] The insulating sheath 1 may also be a flexible sleeve.

[0044] In one embodiment, the flexible insulating shaft 21 is made of a rubber member, which has good elasticity and insulation properties, and can ensure the flexible bending of the flexible body 2, thereby ensuring the detection accuracy of the strain sensor.

[0045] The flexible conductive substrate 23 can be stretched or compressed and is made of elastic material.

[0046] In one embodiment, the flexible conductive substrate 23 is made of a nano-conductive composite material, which has good conductivity and elasticity.

[0047] For example, the nano-conductive composite material may be a graphene / polydimethylsiloxane (PDMS) composite material.

[0048] In one embodiment, each electrode layer 22 includes at least three electrode sheets 221 to better identify a variety of different strain directions in three-dimensional space.

[0049] In one embodiment, each electrode layer 22 includes an insulating substrate, and the surface of the insulating substrate is plated with metal electrode areas in different regions, the metal electrode areas form the electrode sheets 221, and the insulating substrate between two adjacent electrode sheets 221 forms an insulating spacer 222.

[0050] Furthermore, metal electrode regions may be provided on both the upper surface and the lower surface of the insulating substrate.

[0051] The metal electrode region may be a silver electrode region.

[0052] Specifically, during the preparation, metal silver electrodes can be evaporated in different areas on the annular insulating substrate (electrode layer 22) to form metal electrode areas, using double-sided evaporation, and using a mask plate during the evaporation process to ensure that there is no conduction between the partitions; then the prepared insulating substrates are successively inserted into the flexible insulating shaft 21 and fixed; then the flexible conductive substrate 23 is filled between adjacent insulating substrates, and a mold is used to dry and shape it to form a flexible main body 2; finally, the insulating sheath 1 is wrapped around the outside of the flexible main body 2.

[0053] The flexible strain sensor of the above-mentioned embodiment can not only effectively identify the strain size but also effectively identify the strain direction, and has good spatial recognition ability; the overall multi-section structural design is adopted, with the characteristics of high integration and flexibility and bendability. It can scan each node signal line by line to inversely calculate the bending curvature, direction and angle, and is independent of the specific wearer's body shape or wearing part. It has the characteristics of strong compatibility and can be well suitable for the application and promotion of consumer-grade personal wearable motion capture devices.

[0054] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A flexible strain sensor with three-dimensional spatial recognition capability, characterized in that: Including, insulating sheath; A flexible body, the flexible body being located inside the insulating sheath; Among them, the flexible body includes a flexible insulating shaft, on which a plurality of electrode layers are connected in sequence along the axial direction of the flexible insulating shaft, a flexible conductive substrate is filled between two adjacent electrode layers, each of the electrode layers includes a plurality of circumferentially arranged electrode sheets, and an insulating spacer is connected between two adjacent electrode sheets; each of the electrode layers is annular, a mounting hole is formed in the middle of the electrode layer, and the flexible insulating shaft is connected to the mounting hole; the spacing between two adjacent electrode layers is equal; the flexible conductive substrate adopts a nano-conductive composite material; each of the electrode layers includes at least three electrode sheets; when the strain sensor is bent, the spacing between the electrode layers on one side of the flexible insulating shaft increases and the flexible conductive substrate between the electrode layers is compressed, and the resistance decreases; while the spacing between the electrode layers on the other side increases and the flexible conductive substrate between the electrode layers is stretched, and the resistance increases.

2. The flexible strain sensor with three-dimensional spatial recognition capability according to claim 1, characterized in that: All the electrode sheets in each electrode layer are evenly distributed in the circumferential direction.

3. The flexible strain sensor with three-dimensional spatial recognition capability according to claim 1, characterized in that: The insulating sheath is covered on the outside of the flexible body.

4. The flexible strain sensor with three-dimensional spatial recognition capability according to claim 1, characterized in that: The insulating sheath is made of a fabric fiber layer.

5. The flexible strain sensor with three-dimensional spatial recognition capability according to claim 1, characterized in that: The flexible insulating shaft is made of rubber.

6. The flexible strain sensor with three-dimensional spatial recognition capability according to claim 1, characterized in that: Each of the electrode layers comprises an insulating substrate, the surface of the insulating substrate is plated with metal electrode areas in different regions, the metal electrode areas form the electrode sheets, and the insulating spacer between two adjacent electrode sheets forms the insulating spacer.

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