CN112014003A - Flexible sensor for measuring human muscle deformation and preparation method thereof - Google Patents

Abstract

The invention belongs to the related technical field of human motion measurement, and discloses a flexible sensor for measuring human muscle deformation and a preparation method thereof. The flexible sensor comprises a first elastic body layer, a second elastic body layer, a third elastic body layer, a first multi-wall carbon nanotube film and a second multi-wall carbon nanotube film; the first multi-wall carbon nanotube film is disposed on the third elastomer layer, the second elastomer layer is disposed on the third elastomer layer, and It covers the first multi-wall carbon nanotube film; the second multi-wall carbon nanotube film is provided on the second elastomer layer, the first elastomer layer is provided on the second elastomer layer, and it covers the second multi-wall carbon Nanotube film; the first multi-wall carbon nanotube film and the second multi-wall carbon nanotube film are perpendicular to each other, and there is an overlapping area between the first multi-wall carbon nanotube film and the second multi-wall carbon nanotube film. The invention realizes active and passive measurement, has simple operation and strong applicability.

Description

A flexible sensor for measuring human muscle deformation and its preparation method

technical field

The invention belongs to the technical field of human body motion measurement, and more particularly, relates to a flexible sensor for measuring human muscle deformation and a preparation method thereof.

Background technique

If the human body is regarded as a precise machine, the skeletal muscles distributed in the human body are the drivers of this machine. The normal human body has about 650 skeletal muscles. These muscles are the main fixers and movers of the human skeletal system. The stable posture of the human body comes from the balance between opposing forces, and the force generated by skeletal muscles is the main way to control the complex balance between posture and movement.

As the "motor" of the human body, muscles must not only adapt to the complex external environment, but also be regulated by the human nervous system. Muscles have a very complex structure, and each muscle is composed of many sarcomeres that can generate internal force. Because the muscles are distributed inside the human body and the structure is complex, the measurement of the muscle movement state can only start from the skin surface outside the muscle without causing harm to the human body. The most mature method for measuring muscle movement is electromyography (EMG). EMG can monitor the electrical signals transmitted in neurons during active muscle movement. Although EMG signal amplitude can be used to measure muscle force, this relationship is not stable, and there is no correlation between the two under certain conditions. EMG signal is susceptible to factors such as electrode configuration and size, as well as interference from muscles near the measured muscle. In addition, EMG signals can only measure the active movement of the muscle, and when the muscle is passively moved (not controlled by active movement), it cannot be measured because there is no electrical signal. Correspondingly, there is a technical need in the art to develop a flexible sensor for measuring human muscle deformation, which can measure both active and passive states of the muscle, and a preparation method thereof.

SUMMARY OF THE INVENTION

In view of the above defects or improvement needs of the prior art, the present invention provides a flexible sensor for measuring human muscle deformation and a preparation method thereof. Based on the measurement characteristics of the existing muscle motion state, an active and passive sensor is studied and designed. The invention discloses a flexible sensor for measuring human muscle deformation and its preparation method. The flexible sensor starts from muscle deformation, and measures the multi-directional strain and muscle expansion of the skin outside the muscle during muscle movement. Specifically, the flexible sensor uses a multi-walled carbon nanotube (MW-CNTs) film as an electrode to Platinum-catalyzed silicone rubber (Ecoflex) is used as an elastomer, and two layers of vertically arranged multi-wall carbon nanotube films are independently two strain sensors, which can measure the strain in two directions perpendicular to each other in the plane. The overlapping part of the nanotube films constitutes a parallel-plate capacitive sensor, which can be used to measure the information of the force perpendicular to the plane that the sensor is subjected to, thereby realizing the function of measuring both active and passive states. In addition, the flexible sensor is fabricated by layered molding, and the operation is simple and easy to implement.

In order to achieve the above object, according to one aspect of the present invention, a flexible sensor for measuring human muscle deformation is provided, the flexible sensor includes a first elastomer layer, a second elastomer layer, a third elastomer layer, a a multi-wall carbon nanotube film and a second multi-wall carbon nanotube film; the first multi-wall carbon nanotube film is disposed on the third elastomer layer, and the second elastomer layer is disposed on the first three elastomer layers covering the first multi-wall carbon nanotube film; the second multi-wall carbon nanotube film is disposed on the second elastomer layer, and the first elastomer layer is disposed on the on the second elastomer layer and covering the second multi-wall carbon nanotube film; the first multi-wall carbon nanotube film and the second multi-wall carbon nanotube film are perpendicular to each other, and the There is an overlapping area between the first multi-walled carbon nanotube film and the second multi-walled carbon nanotube film;

The first multi-walled carbon nanotube film and the second multi-walled carbon nanotube film are independent of each other as two strain sensors, so as to realize the measurement of strains in two directions perpendicular to each other in the measurement plane; The overlapping region of the walled carbon nanotube film and the second multi-walled carbon nanotube film constitutes a parallel plate capacitive sensor, so as to measure the pressure that the flexible sensor is subjected to and is perpendicular to the measurement plane.

Further, when the flexible sensor generates lateral strain, the initial resistance value of the first multi-wall carbon nanotube film changes accordingly, which is calculated based on the change in the resistance value of the first multi-wall carbon nanotube film. Lateral strain.

Further, when the flexible sensor generates longitudinal strain, the initial resistance value of the second multi-wall carbon nanotube film changes accordingly, which is calculated based on the change in the resistance value of the second multi-wall carbon nanotube film. longitudinal strain.

Further, when the flexible sensor is subjected to pressure along its thickness direction, the capacitance formed by the overlapping area of the first multi-wall carbon nanotube film and the second multi-wall carbon nanotube film changes, based on the obtained The amount of capacitance change to obtain the pressure on the flexible sensor.

Further, the opposite ends of the first multi-wall carbon nanotube film and the opposite ends of the second multi-wall carbon nanotube film are respectively connected with copper wires. During operation, the copper wires are connected to the outside. measurement circuit.

Further, the first elastomer layer, the second elastomer layer and the third elastomer layer constitute an elastomer, the first multi-wall carbon nanotube film and the second multi-wall carbon nanotube film The membrane is embedded within the elastomer; the elastomer is made of transparent platinum-catalyzed silica gel.

Further, the first multi-walled carbon nanotube film is in the shape of a middle shape, and includes a first connecting portion, a second connecting portion and an intermediate portion, and the first connecting portion and the second connecting portion are respectively connected to the On the opposite sides of the middle portion, the first connecting portion and the second connecting portion are both rectangular, and the middle portion is square.

Further, the structure of the first multi-wall carbon nanotube film is the same as that of the second multi-wall carbon nanotube film.

According to another aspect of the present invention, there is provided a method for preparing a flexible sensor for measuring human muscle as described above, the preparation method comprising the following steps:

(1) preparing a third elastomer layer, and preparing a first multi-walled carbon nanotube film on the third elastomer layer by spraying;

(2) preparing a second elastomer layer on the first multi-wall carbon nanotube film; and preparing a second multi-wall carbon nanotube film on the second elastomer layer;

(3) A first elastomer layer is prepared on the second multi-walled carbon nanotube film, thereby obtaining the flexible sensor.

Further, the third elastomer layer, the second elastomer layer and the first elastomer layer are all obtained by coating with a platinum-catalyzed silica gel solution and heating at 70° C. for 30 minutes.

In general, compared with the prior art through the above technical solutions conceived by the present invention, the flexible sensor for measuring human muscle deformation and its preparation method provided by the present invention mainly have the following features:

Beneficial effects:

1. The first multi-walled carbon nanotube film and the second multi-walled carbon nanotube film are independent of each other as two strain sensors, so as to realize the measurement of strains in two directions perpendicular to each other in the measurement plane; The overlapping area of a multi-walled carbon nanotube film and the second multi-walled carbon nanotube film constitutes a parallel-plate capacitive sensor to measure the pressure perpendicular to the measurement plane on the flexible sensor, thereby simultaneously achieving The measurement of active and passive states is improved, the applicability and flexibility are improved, and the functions are relatively complete.

2. The elastomer is made of transparent platinum-catalyzed silica gel, and the thickness of the flexible sensor is less than 1 mm, which has very good stretchability, can fit the skin well, and has good flexibility. Wearability.

3. The flexible sensor is made by layered molding, which is simple to operate and easy to implement; the first multi-wall carbon nanotube film and the second multi-wall carbon nanotube film are embedded in the elastomer, so that the The flexible sensor is compact.

4. The present invention uses the multi-walled carbon nanotube film as the electrode, and the multi-walled carbon nanotube has extremely high strength and toughness, as well as excellent mechanical properties, and thus has good extensibility and flexibility.

Description of drawings

1 is a schematic structural diagram of a flexible sensor for measuring human muscle deformation provided by a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of the measurement principle of the flexible sensor for measuring human muscle deformation in FIG. 1;

FIG. 3 is a schematic diagram of the preparation process of the flexible sensor for measuring human muscle deformation in FIG. 1;

FIG. 4 is a schematic diagram of a resistance measurement circuit of the flexible sensor for measuring human muscle deformation in FIG. 1 .

Throughout the drawings, the same reference numerals are used to refer to the same elements or structures, wherein: 1-first elastomeric layer, 2-second elastomeric layer, 3-third elastomeric layer, 4-first Multi-walled carbon nanotube film, 5-second multi-walled carbon nanotube film, 6-copper wire, 7-conductive silver glue, 8-aluminum substrate, 9-airbrush, 10-mask.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

Please refer to FIG. 1 , FIG. 2 and FIG. 4 . A preferred embodiment of the present invention provides a flexible sensor for measuring human muscle deformation. The flexible sensor includes an elastic body and a first multi-walled body respectively embedded in the elastic body. The carbon nanotube film 4, the second multi-wall carbon nanotube film 5, and the copper wire 6, the first multi-wall carbon nanotube film 4 and the second multi-wall carbon nanotube film 5 are spaced apart, and both Independent. The opposite ends of the first multi-walled carbon nanotube film 4 and the opposite ends of the second multi-walled carbon nanotube film 5 are respectively connected with the copper wires 6, and the copper wires 6 protrude from the copper wires 6. The elastic body is used for connecting with an external measuring circuit.

The elastomer is made of transparent platinum-catalyzed silica gel, which is substantially rectangular. The elastomer is used to carry the first multi-walled carbon nanotube film 4 and the second multi-walled carbon nanotube film 5 , which includes a first elastomer layer 1 , a second elastomer layer 2 and a third elastic layer body layer 3, the second multi-walled carbon nanotube film 5 is provided on the third elastomer layer 3, the second elastomer layer 2 is provided on the third elastomer layer 3, and it covers The second multi-walled carbon nanotube film 5 . The first multi-walled carbon nanotube film 4 is disposed on the second elastomer layer 2, and the first elastomer layer 1 is disposed on the second elastomer layer 2 and covers the first Multi-walled carbon nanotube films 4.

The first multi-wall carbon nanotube film 4 and the second multi-wall carbon nanotube film 5 are arranged perpendicular to each other, and the two are respectively independent strain sensors. The first multi-walled carbon nanotube film 4 is basically in the shape of a "middle" shape, which includes a first connecting part, a second connecting part and a middle part, and the first connecting part and the second connecting part are respectively connected to the On the opposite sides of the middle portion, the first multi-walled carbon nanotube film 4 is connected to the copper wire 6 through the first connection portion and the second connection portion. In this embodiment, the first connecting part and the second connecting part are both rectangular, and the middle part is square; the structure of the first multi-wall carbon nanotube film 4 is the same as that of the second multi-wall carbon The structure of the nanotube film 5 is the same, the middle part of the first multi-wall carbon nanotube film 4 and the middle part of the second multi-wall carbon nanotube film 5 overlap in the thickness direction of the flexible sensor to form a parallel plate Capacitive structure.

During operation, the first connection part and the second connection part produce obvious resistance changes when strain occurs, and when the flexible sensor produces lateral strain, the initial resistance value of the first multi-walled carbon nanotube film 4 R1 changes accordingly; when the flexible sensor generates longitudinal strain, the initial resistance value R2 of the second multi-walled carbon nanotube film 5 changes accordingly; when the flexible sensor is subjected to pressure along its thickness direction, The distance between the first multi-walled carbon nanotube film 4 and the second multi-walled carbon nanotube film 5 changes, so that the middle part of the first multi-walled carbon nanotube film 4 and the second The capacitance formed by the middle part of the multi-walled carbon nanotube film 5 changes, so that the flexible sensor can simultaneously measure the strain in two mutually perpendicular directions in the plane and the pressure in the direction perpendicular to the plane. In this embodiment, the measurement plane is a horizontal plane.

Referring to FIG. 3 , the present invention also provides a method for preparing a flexible sensor for measuring human muscle deformation. The preparation method is used to prepare the above-mentioned flexible sensor for measuring human muscle deformation, which specifically includes the following steps :

Step 1, prepare a third elastomer layer on the aluminum substrate.

Specifically, an aluminum substrate 8 is provided, and the platinum-catalyzed silica gel solutions A and B are mixed according to a mass ratio of 1:1 and stirred evenly, and then placed in a vacuum for 15 minutes to remove air bubbles; then, automatic casting coating is used. The prepared platinum-catalyzed silica gel solution was coated on the aluminum substrate 8 by machine, and heated at 70° C. for 30 minutes to obtain the third elastomer layer 3 .

In step 2, a first multi-wall carbon nanotube film is prepared on the third elastomer layer.

Specifically, the multi-walled carbon nanotube powder was added to a 95% absolute ethanol solution, dispersed for 30 minutes using an ultrasonic disperser, and the third elastomer layer 3 was covered with a mask plate 10; then, The obtained carbon nanotube ethanol dispersion is spray-printed on the third elastomer layer 3 by using an airbrush 9, and sprayed again after the ethanol is volatilized, and repeated 3 to 4 times, so that the third elastomer layer 3 can be sprayed on the third elastomer layer 3. A uniform first multi-walled carbon nanotube film 4 is formed thereon.

In step 3, the opposite ends of the first multi-walled carbon nanotube film 4 are connected to copper wires 6 respectively. Specifically, use sandpaper to polish both ends of the copper enameled wire to remove the insulating paint at both ends, use conductive silver glue 7 to fix the copper enameled wire on the opposite ends of the first multi-wall carbon nanotube film, and heat at 70 degrees Celsius After 20 minutes, the conductive silver glue 7 is cured, so that the opposite ends of the first multi-walled carbon nanotube film 4 are respectively connected to the copper wires 6 .

In step 4, a second elastomer layer 2 is prepared on the first multi-walled carbon nanotube film. Specifically, similar to the first step, after the elastomer is cured, the first carbon nanotube film 4 and the copper wires 6 connected thereto are embedded in the first elastomer layer 2 and the second elastomer layer 3 .

Step 5, prepare a second multi-wall carbon nanotube film 5 on the second elastomer layer 2; then, connect the opposite ends of the second multi-wall carbon nanotube film 5 to copper wires 6 respectively; finally , prepare a first elastomer layer 1 on the second multi-walled carbon nanotube film 5, and remove the aluminum substrate 8 to obtain the flexible sensor. Wherein, when preparing the second multi-wall carbon nanotube film 5, the mask plate 10 needs to be rotated by 90° to ensure that the first multi-wall carbon nanotube film 4 and the second multi-wall carbon nanotube film The films 5 are perpendicular to each other.

The resistance data acquisition of the flexible sensor uses a voltage divider circuit, and the corresponding resistance is calculated by measuring the voltage across the first multi-wall carbon nanotube film 4 and the voltage across the second multi-wall carbon nanotube film 5 respectively. , its resistance has a fixed relationship with the corresponding strain, specifically:

R ₁₁ =R ₀ ×U ₁ /(UU ₁ ) (1)

R ₂₁ =R ₀ ×U ₂ /(UU ₂ ) (2)

ε ₁ =f(R ₁₁ ) (3)

ε ₂ =f(R ₂₁ ) (4)

In the formula, R ₀ is the series fixed resistance; R ₁₁ is the resistance of the first multi-wall carbon nanotube film when strain occurs; U ₁ is the voltage across the first multi-wall carbon nanotube film; U is the total voltage; R ₂₁ is the resistance of the second multi-wall carbon nanotube film when strain is generated; U ₂ is the voltage across the second multi-wall carbon nanotube film; ε ₁ is the lateral strain received by the flexible sensor; f(R ₁₁ ) is the calculation formula of the calibrated strain ε ₁ ; ε ₂ is the longitudinal strain of the flexible sensor; f(R ₂₁ ) is the calculation formula of the calibrated strain ε ₂ .

The present invention provides a flexible sensor for measuring human muscle deformation and a preparation method thereof. The flexible sensor has two multi-walled carbon nanotube films arranged perpendicular to each other, and the two are embedded in an elastic body respectively. The carbon nanotube films are independent strain sensors to measure the strain in two directions perpendicular to each other, and the overlapping parts of the two multi-walled carbon nanotube films can measure the pressure of the sensor perpendicular to the measurement plane, so that the active and passive The state can be measured, the structure is simple, the operation is easy, and the applicability is strong.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (10)

1. A flexible sensor for measuring deformation of a muscle of a human body, comprising:

the flexible sensor comprises a first elastomer layer (1), a second elastomer layer (2), a third elastomer layer (3), a first multi-walled carbon nanotube film (4) and a second multi-walled carbon nanotube film (5); the first multi-walled carbon nanotube film (4) is arranged on the third elastomeric layer (3), the second elastomeric layer (2) is arranged on the third elastomeric layer (3) and it covers the first multi-walled carbon nanotube film (4); the second multi-walled carbon nanotube film (5) is arranged on the second elastomer layer (2), the first elastomer layer (1) is arranged on the second elastomer layer (2) and covers the second multi-walled carbon nanotube film (5); the first multi-walled carbon nanotube film (4) and the second multi-walled carbon nanotube film (5) are perpendicular to each other, and an overlapping area is formed between the first multi-walled carbon nanotube film (4) and the second multi-walled carbon nanotube film (5);

the first multi-walled carbon nanotube film (4) and the second multi-walled carbon nanotube film (5) are mutually independent to form two strain sensors so as to realize measurement of strains in two directions which are mutually vertical in a measurement plane; the area where the first multi-walled carbon nanotube film (4) and the second multi-walled carbon nanotube film (5) overlap each other constitutes a parallel plate capacitive sensor for measuring the pressure perpendicular to the measuring plane to which the flexible sensor is subjected.

2. A flexible sensor for human muscle deformation measurement as claimed in claim 1, wherein: when the flexible sensor generates transverse strain, the initial resistance value of the first multi-walled carbon nanotube film (4) is changed, and the transverse strain is calculated based on the resistance value change of the first multi-walled carbon nanotube film (4).

3. A flexible sensor for human muscle deformation measurement as claimed in claim 1, wherein: when the flexible sensor generates longitudinal strain, the initial resistance value of the second multi-walled carbon nanotube film (5) is changed, and the longitudinal strain is calculated based on the resistance value variation of the second multi-walled carbon nanotube film (5).

4. A flexible sensor for human muscle deformation measurement as claimed in claim 1, wherein: when the flexible sensor is pressed along the thickness direction of the flexible sensor, the capacitance formed by the overlapped area of the first multi-wall carbon nanotube film (4) and the second multi-wall carbon nanotube film (5) is changed, and the pressure applied to the flexible sensor is obtained based on the obtained capacitance change amount.

5. A flexible sensor for human muscle deformation measurement according to any one of claims 1 to 4, wherein: the two ends of the first multi-walled carbon nanotube film (4) which are back to back and the two ends of the second multi-walled carbon nanotube film (5) which are back to back are respectively connected with a copper wire (6), and the copper wires (6) are connected to an external measuring circuit during working.

6. A flexible sensor for human muscle deformation measurement according to any one of claims 1 to 4, wherein: the first elastomer layer (1), the second elastomer layer (2) and the third elastomer layer (3) constitute an elastomer, and the first multi-walled carbon nanotube film (4) and the second multi-walled carbon nanotube film (5) are embedded in the elastomer; the elastomer is made of transparent platinum-catalyzed silica gel.

7. A flexible sensor for human muscle deformation measurement according to any one of claims 1 to 4, wherein: the first multi-walled carbon nanotube film (4) is in a Chinese character 'zhong' shape and comprises first connecting portions, second connecting portions and a middle portion, the first connecting portions and the second connecting portions are connected to two sides of the middle portion in a back-to-back mode respectively, the first connecting portions and the second connecting portions are rectangular, and the middle portion is square.

8. The flexible sensor for human muscle deformation measurement according to claim 7, wherein: the structure of the first multi-walled carbon nanotube film (4) is the same as the structure of the second multi-walled carbon nanotube film (5).

9. A method for manufacturing a flexible sensor for measuring deformation of muscles of the human body according to any one of claims 1 to 8, comprising the steps of:

(1) preparing a third elastomer layer (3), and preparing a first multi-walled carbon nanotube film (4) on the third elastomer layer (3) by adopting a spraying mode;

(2) -preparing a second elastomeric layer (2) on said first multi-walled carbon nanotube film (4), and preparing a second multi-walled carbon nanotube film (5) on said second elastomeric layer (2);

(3) -preparing a first elastomeric layer (1) on said second multi-walled carbon nanotube film (5), thereby obtaining said flexible sensor.

10. The method of manufacturing a flexible sensor for measurement of human muscle deformation of claim 9, wherein: the third elastomer layer (3), the second elastomer layer (2) and the first elastomer layer (1) are all obtained by coating a platinum-catalyzed silica gel solution and then heating the coated solution at 70 ℃ for 30 minutes.

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