Temperature strain sensor for robot joint and preparation method thereof

Abstract

The invention belongs to the technical field of sensors, and particularly relates to a temperature strain sensor for a robot joint and a preparation method thereof.The temperature strain sensor comprises an upper fabric packaging layer, an upper bonding layer, an upper electrode layer, a sensitive layer, a temperature sensitive layer, a lower bonding layer and a lower fabric packaging layer which are sequentially stacked from top to bottom; and a lower electrode layer is arranged in the temperature sensitive layer. The temperature strain sensor provided by the invention has the advantages of miniaturization, ultrahigh flexibility, high practicability and the like, adopts the upper fabric packaging layer and the lower fabric packaging layer, has a very good effect on conformal attachment and operation state detection of robot skin, can realize 40% large strain stretching and a wide temperature detection range from-20 DEG C to 30 DEG C, and has a wide application prospect. And the health state of the robot joint can be well judged through simultaneous monitoring of the strain and the temperature.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and particularly relates to a temperature strain sensor for a robot joint and a preparation method thereof. Background Art

[0002] With the rapid development of intelligent robot technology, humanoid robots are also developing rapidly. Tactile perception and human-machine interaction of humanoid robots have become a popular technical problem. Humanoid robots need to perform various complex tasks in the environment, such as disaster rescue, healthcare, human-machine interaction, etc. The control and limitation of the joint parts of humanoid robots are crucial for ensuring the safety of the robots. The joint parts are usually equipped with sensors and actuators, which enable the robots to sense the position, speed and force of the joints and perform precise control. The flexible strain temperature sensor can be well combined with the joint parts of the robot, and the running state of the robot can be well monitored in real time through the two parameters of strain and temperature. At present, the processing methods of the various layer structures of the flexible strain temperature sensor mainly rely on physical vapor deposition, with expensive process equipment, harsh process conditions and high time costs. Summary of the Invention

[0003] The present invention provides a temperature strain sensor for a robot joint and a preparation method thereof for the above problems.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The temperature strain sensor for a robot joint includes an upper fabric encapsulation layer, an upper bonding layer, an upper electrode layer, a sensitive layer, a temperature sensitive layer, a lower bonding layer and a lower fabric encapsulation layer which are sequentially stacked from top to bottom. A lower electrode layer is arranged inside the temperature sensitive layer.

[0006] Further, the temperature sensitive layer is coiled into a U-shaped by a serpentine structure to reduce the influence of strain on temperature.

[0007] Still further, a plurality of grooves are arranged on the upper surface of the sensitive layer to improve the sensitivity of the sensitive layer.

[0008] The preparation method of the temperature strain sensor for a robot joint includes the following steps:

[0009] S1, Preparation of the upper fabric encapsulation layer and the lower fabric encapsulation layer: Cut the fabric according to the set size to obtain the upper fabric encapsulation layer and the lower fabric encapsulation layer;

[0010] S2, Preparation of the upper bonding layer and the lower bonding layer: Cut the thermoplastic polyurethane elastomer film by laser etching according to the set size to obtain the upper bonding layer and the lower bonding layer;

[0011] S3, Preparation of the upper bonding layer - upper electrode layer: Take the laser-etched upper bonding layer, clean it with alcohol and deionized water for 5 min, dry it with a hot air blower, fix it on the screen printing table with tape, place the electrode layer stencil on the upper bonding layer, determine the position of the upper electrode layer through the frame of the electrode layer stencil, dip a cotton swab in conductive ink and place it on the electrode layer stencil, perform printing with a squeegee at a 45-degree inclination, and then place the printed upper bonding layer - upper electrode layer on a 90 °C heating table and heat it for 30 min to obtain the cured upper bonding layer - upper electrode layer;

[0012] S4, Repeat S3 to prepare the lower bonding layer - lower electrode layer;

[0013] S5, Preparation of the lower bonding layer - lower electrode layer - temperature-sensitive layer: Take the lower bonding layer - lower electrode layer, fix it on the screen printing table with tape, place the temperature stencil above the lower bonding layer, determine the position of the temperature-sensitive layer through the frame of the temperature stencil, dip a cotton swab in temperature-sensitive ink and place it on the temperature stencil, perform printing with a squeegee at a 45-degree inclination, and then place the printed lower bonding layer - lower electrode layer - temperature-sensitive layer on a 90 °C heating table and heat it for 40 min to obtain the cured lower bonding layer - lower electrode layer - temperature-sensitive layer;

[0014] S6, Preparation of the sensitive layer: According to the set size, cut the thermoplastic polyurethane elastomer film by laser etching, and etch multiple grooves on the upper surface of the cut thermoplastic polyurethane elastomer film by laser etching to obtain the sensitive layer;

[0015] S7, Align the lower bonding layer - lower electrode layer - temperature-sensitive layer with the lower fabric encapsulation layer with tweezers, and then hot press at 100 °C for 90 s with a hot press to form the lower fabric encapsulation layer - lower bonding layer - lower electrode layer - temperature-sensitive layer. Align the upper bonding layer - upper electrode layer, sensitive layer with the upper fabric encapsulation layer with tweezers, and then hot press at 100 °C for 90 s with a hot press to form the upper fabric encapsulation layer - upper bonding layer - upper electrode layer - sensitive layer;

[0016] S8, Hot press the upper fabric encapsulation layer - upper bonding layer - upper electrode layer - sensitive layer and the lower fabric encapsulation layer - lower bonding layer - lower electrode layer - temperature-sensitive layer at 100 °C for 90 s with a hot press to obtain the upper fabric encapsulation layer - upper bonding layer - upper electrode layer - sensitive layer - temperature-sensitive layer - lower electrode layer - lower bonding layer - lower fabric encapsulation layer. After it cools down, obtain the temperature strain sensor.

[0017] Further, the conductive ink in S3 is prepared by dissolving flaky silver powder and thermoplastic polyurethane elastomer in N,N-dimethylformamide according to a mass ratio of 2:1. Specifically: Take a reagent bottle and add 5 mL of N,N-dimethylformamide solution, then add 3 g of flaky silver powder with a particle size of 1 um and 1.5 g of thermoplastic polyurethane elastomer particles. Under the condition of 90 °C, stir well with a magnetic stirrer for 60 min, and then perform vacuum filtration for 10 min to obtain the conductive ink.

[0018] Furthermore, the temperature-sensitive ink in S5 is prepared by dissolving conductive carbon paste and thermoplastic polyurethane elastomer in N,N-dimethylformamide according to a mass ratio of 1:1. Specifically: Take a reagent bottle and add 5 mL of N,N-dimethylformamide solution, then add 1.5 g of conductive carbon paste and 1.5 g of thermoplastic polyurethane elastomer particles. Under the condition of 90 °C, stir well with a magnetic stirrer for 60 min, and then perform vacuum filtration for 10 min to obtain the temperature-sensitive ink.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] A temperature strain sensor proposed by the present invention has the advantages of miniaturization, ultra-high flexibility, and strong practicability. By adopting an upper fabric encapsulation layer and a lower fabric encapsulation layer, it has a good effect on the conformal attachment of the robot skin and the detection of the running state, and can achieve a large strain tensile of 40% and a wide temperature detection range of -20 °C to 30 °C. The simultaneous monitoring of strain and temperature can well judge the health state of the robot joints. In addition, the present invention is prepared by a screen printing process, which has the advantages of simple preparation and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the present invention;

[0022] Figure 2 is an assembly schematic diagram of the lower bonding layer, lower electrode layer and temperature-sensitive layer of the present invention;

[0023] Figure 3 is a top view of the sensitive layer of the present invention;

[0024] Figure 4 is a top view of the temperature-sensitive layer of the present invention;

[0025] Figure 5 is a temperature test data graph of the present invention;

[0026] Figure 6 is a strain test data graph of the present invention;

[0027] In the figure, there are an upper fabric encapsulation layer 1, an upper bonding layer 2, an upper electrode layer 3, a sensitive layer 4, a temperature-sensitive layer 5, a lower electrode layer 6, a lower bonding layer 7, and a lower fabric encapsulation layer 8. Detailed implementation mode

[0028] To further elaborate on the technical solution of the present invention, the present invention will be further described below through embodiments.

[0029] As Figures 1 to 4 shown, the temperature strain sensor for a robot joint includes an upper fabric encapsulation layer 1, an upper bonding layer 2, an upper electrode layer 3, a sensitive layer 4, a temperature-sensitive layer 5, a lower bonding layer 7, and a lower fabric encapsulation layer 8 that are sequentially stacked from top to bottom. A plurality of grooves are provided on the upper surface of the sensitive layer 4, and a lower electrode layer 6 is provided inside the temperature-sensitive layer 5. The temperature-sensitive layer 5 is coiled into a U-shaped by a serpentine structure.

[0030] The preparation method of the temperature strain sensor for a robot joint includes the following steps:

[0031] S1, Preparation of the upper fabric encapsulation layer 1 and the lower fabric encapsulation layer 8: Cut the fabric according to the set size to obtain the upper fabric encapsulation layer 1 and the lower fabric encapsulation layer 8;

[0032] S2, Preparation of the upper bonding layer 2 and the lower bonding layer 7: Cut the thermoplastic polyurethane elastomer film by laser etching according to the set size to obtain the upper bonding layer 2 and the lower bonding layer 7;

[0033] S3, Preparation of the upper bonding layer 2 - upper electrode layer 3: Take the laser-etched upper bonding layer 2, wash it with alcohol and deionized water for 5 min, dry it with a hot air blower, fix it on the screen printing table with tape, place the electrode layer stencil on the upper bonding layer 2, determine the position of the upper electrode layer 3 through the frame of the electrode layer stencil, dip a cotton swab in conductive ink and place it on the electrode layer stencil, print with a squeegee at a 45-degree angle, and then place the printed upper bonding layer 2 - upper electrode layer 3 on a 90 °C heating table and heat it for 30 min to obtain the cured upper bonding layer 2 - upper electrode layer 3;

[0034] S4, Repeat S3 to prepare the lower bonding layer 7 - lower electrode layer 6;

[0035] S5, Preparation of the lower bonding layer 7 - lower electrode layer 6 - temperature-sensitive layer 5: Remove the lower bonding layer 7 - lower electrode layer 6, fix it on the screen printing table with tape, place the temperature stencil above the lower bonding layer 7, determine the position of the temperature-sensitive layer 5 through the frame of the temperature stencil, dip a cotton swab in the temperature-sensitive ink and place it on the temperature stencil, perform printing with a squeegee at a 45-degree tilt, and then place the printed lower bonding layer 7 - lower electrode layer 6 - temperature-sensitive layer 5 on a heating table at 90 °C and heat it for 40 min to obtain the cured lower bonding layer 7 - lower electrode layer 6 - temperature-sensitive layer 5;

[0036] S6, Preparation of the sensitive layer 4: Cut the thermoplastic polyurethane elastomer film according to the set size by means of laser etching, and etch a plurality of grooves on the upper surface of the cut thermoplastic polyurethane elastomer film by means of laser etching to obtain the sensitive layer 4;

[0037] S7, Align the lower bonding layer 7 - lower electrode layer 6 - temperature-sensitive layer 5 with the lower fabric encapsulation layer 8 with tweezers, and then hot-press at 100 °C for 90 s with a hot press to form the lower fabric encapsulation layer 8 - lower bonding layer 7 - lower electrode layer 6 - temperature-sensitive layer 5. Align the upper bonding layer 2 - upper electrode layer 3, sensitive layer 4 with the upper fabric encapsulation layer 1 with tweezers, and then hot-press at 100 °C for 90 s with a hot press to form the upper fabric encapsulation layer 1 - upper bonding layer 2 - upper electrode layer 3 - sensitive layer 4;

[0038] S8, Hot-press the upper fabric encapsulation layer 1 - upper bonding layer 2 - upper electrode layer 3 - sensitive layer 4 and the lower fabric encapsulation layer 8 - lower bonding layer 7 - lower electrode layer 6 - temperature-sensitive layer 5 at 100 °C for 90 s with a hot press to obtain the upper fabric encapsulation layer 1 - upper bonding layer 2 - upper electrode layer 3 - sensitive layer 4 - temperature-sensitive layer 5 - lower electrode layer 6 - lower bonding layer 7 - lower fabric encapsulation layer 8. After it cools down, a temperature strain sensor is obtained.

[0039] The conductive ink in S3 is made by dissolving flaky silver powder and thermoplastic polyurethane elastomer in N,N-dimethylformamide according to a mass ratio of 2:1. Specifically: Take a reagent bottle and add 5 mL of N,N-dimethylformamide solution, then add 3 g of flaky silver powder with a particle size of 1 um and 1.5 g of thermoplastic polyurethane elastomer particles. Under the condition of 90 °C, stir well with a magnetic stirrer for 60 min, and then perform vacuum filtration for 10 min to obtain the conductive ink.

[0040] The temperature-sensitive ink in S5 is prepared by dissolving conductive carbon paste and thermoplastic polyurethane elastomer in N,N-dimethylformamide at a mass ratio of 1:1. Specifically, take a reagent bottle and add 5 mL of N,N-dimethylformamide solution, then add 1.5 g of conductive carbon paste and 1.5 g of thermoplastic polyurethane elastomer particles. Under the condition of 90 °C, stir well with a magnetic stirrer for 60 min, and then perform vacuum filtration for 10 min to obtain the temperature-sensitive ink.

[0041] The foregoing has shown and described the main features and advantages of the present invention. For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-described exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to embrace all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

[0042] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A temperature strain sensor for robot joints, characterized in that: The invention comprises an upper fabric packaging layer (1), an upper bonding layer (2), an upper electrode layer (3), a sensitive layer (4), a temperature sensitive layer (5), a lower bonding layer (7) and a lower fabric packaging layer (8) which are stacked in sequence from top to bottom, wherein a lower electrode layer (6) is arranged inside the temperature sensitive layer (5).

2. The temperature strain sensor for robot joints according to claim 1, characterized in that: The temperature sensitive layer (5) is coiled into a coiled shape by a serpentine structure.

3. The temperature strain sensor for robot joints according to claim 2, characterized in that: A plurality of grooves are arranged on the upper surface of the sensitive layer (4).

4. The method for preparing the temperature strain sensor for robot joints according to claim 3, characterized in that: The following steps are involved: S1, preparation of an upper fabric encapsulation layer (1) and a lower fabric encapsulation layer (8): cutting the fabric according to a set size to obtain an upper fabric encapsulation layer (1) and a lower fabric encapsulation layer (8); S2, preparation of the upper bonding layer (2) and the lower bonding layer (7): cutting the thermoplastic polyurethane elastomer film according to the set size by laser etching to obtain the upper bonding layer (2) and the lower bonding layer (7); S3, preparation of upper bonding layer (2) - upper electrode layer (3): take the laser-etched upper bonding layer (2), clean it with alcohol and deionized water for 5 minutes, blow dry it with a hot air blower, fix it on the screen printing table with tape, place the electrode layer screen on the upper bonding layer (2), determine the position of the upper electrode layer (3) by the plate frame of the electrode layer screen, dip a cotton swab in conductive ink and place it on the electrode layer screen, use a scraper to print at a 45-degree tilt, and then place the printed upper bonding layer (2) - upper electrode layer (3) on a 90°C heating table and heat it for 30 minutes to obtain a cured upper bonding layer (2) - upper electrode layer (3); S4, repeat S3 to prepare a lower bonding layer (7)-lower electrode layer (6); S5, preparation of the lower bonding layer (7) - lower electrode layer (6) - temperature sensitive layer (5): remove the bonding layer (7) - lower electrode layer (6), fix it on the screen printing table with tape, place the temperature screen above the lower bonding layer (7), determine the position of the temperature sensitive layer (5) by the plate frame of the temperature screen, dip the temperature sensitive ink with a cotton swab and place it on the temperature screen, use a scraper to print at a 45-degree angle, and then place the printed lower bonding layer (7) - lower electrode layer (6) - temperature sensitive layer (5) on a 90°C heating table and heat it for 40 minutes to obtain a cured lower bonding layer (7) - lower electrode layer (6) - temperature sensitive layer (5); S6, preparation of the sensitive layer (4): cutting the thermoplastic polyurethane elastomer film according to the set size by laser etching, and etching a plurality of grooves on the upper surface of the cut thermoplastic polyurethane elastomer film by laser etching to obtain the sensitive layer (4); S7, using tweezers to align the lower bonding layer (7) - lower electrode layer (6) - temperature sensitive layer (5) with the lower fabric packaging layer (8), and then using a hot press to heat press for 90 seconds at 100°C to form a lower fabric packaging layer (8) - lower bonding layer (7) - lower electrode layer (6) - temperature sensitive layer (5); using tweezers to align the upper bonding layer (2) - upper electrode layer (3) and sensitive layer (4) with the upper fabric packaging layer (1), and then using a hot press to heat press for 90 seconds at 100°C to form an upper fabric packaging layer (1) - upper bonding layer (2) - upper electrode layer (3) - sensitive layer (4); S8, use a hot press to hot press the upper fabric packaging layer (1) - upper bonding layer (2) - upper electrode layer (3) - sensitive layer (4) and the lower fabric packaging layer (8) - lower bonding layer (7) - lower electrode layer (6) - temperature sensitive layer (5) at 100°C for 90 seconds to obtain the upper fabric packaging layer (1) - upper bonding layer (2) - upper electrode layer (3) - sensitive layer (4) - temperature sensitive layer (5) - lower electrode layer (6) - lower bonding layer (7) - lower fabric packaging layer (8), and after cooling, a temperature strain sensor is obtained.

5. The method for preparing a temperature strain sensor for a robot joint according to claim 4, characterized in that: The conductive ink in S3 is prepared by dissolving flaky silver powder and thermoplastic polyurethane elastomer in N,N-dimethylformamide in a mass ratio of 2:1, specifically: take a reagent bottle, add 5 mL of N,N-dimethylformamide solution, then add 3 g of flaky silver powder with a particle size of 1 um and 1.5 g of thermoplastic polyurethane elastomer particles, stir thoroughly for 60 minutes with a magnetic stirrer at 90°C, and then vacuum filter for 10 minutes to obtain the conductive ink.

6. The method for preparing a temperature strain sensor for a robot joint according to claim 4, characterized in that: The temperature sensitive ink in S5 is prepared by dissolving a conductive carbon paste and a thermoplastic polyurethane elastomer in N,N-dimethylformamide in a mass ratio of 1:

1. Specifically, a reagent bottle is added with 5 mL of N,N-dimethylformamide solution, and then 1.5 g of conductive carbon paste and 1.5 g of thermoplastic polyurethane elastomer particles are added. The mixture is stirred for 60 minutes with a magnetic stirrer at 90°C, and then vacuum filtered for 10 minutes to obtain the temperature sensitive ink.

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