A three-dimensional contact force sensor of the air chamber type

Abstract

The application provides a gas chamber type three-dimensional contact force sensor, which is characterized in that a plurality of air pressure sensors are arranged in closed soft air chambers on a bottom plate of the gas chamber type three-dimensional contact force sensor; the soft air chambers are formed by surrounding elastic contact body shells (4) arranged on the bottom plate and located above or beside the air pressure sensors; when the elastic contact body shells are deformed under the action of external three-dimensional force, the soft air chambers of the air pressure sensors at the force receiving positions are deformed and the air pressure in the soft air chambers is changed, the gas chamber type three-dimensional contact force sensor processes the air pressure data of the soft air chambers measured by the air pressure sensors to obtain external three-dimensional force information; the application has three-dimensional force detection capability, simple preparation process, low manufacturing cost, low requirement for the operation environment and is suitable for mass production.

Description

Technical Field

[0001] This invention relates to the field of air chamber type sensor technology, and in particular to an air chamber type three-dimensional contact force sensor. Background Technology

[0002] Tactile sensors convert various mechanical measurements into electrical signals and are widely used in various fields of production and daily life. With the rapid development of electromechanical devices such as portable electronic devices, wearable technologies, and intelligent robots, miniature sensors with advantages such as small size, light weight, low power consumption, and high reliability are beginning to be used on a large scale. Based on the properties of the materials used in their fabrication, mechanical sensors can be divided into all-solid-state, semi-solid-state, and flexible structures. Among them, flexible structures can be used in tactile sensors, robot skin, and other applications that require appropriate elasticity or adaptation to complex shapes and environments, thus having wider applicability.

[0003] In recent years, tactile sensors have attracted increasing attention from researchers. Over the past two decades, researchers have conducted extensive studies on sensor structure design and conduction mechanisms. Current mainstream conduction methods include piezoresistive, capacitive, and piezoelectric sensors. These all rely on changes in the electrical properties of materials to transmit mechanical sensations, including tactile information (force) and proprioceptive information (shape). However, the fabrication process of these tactile sensors is generally complex, requiring the mixing of flexible and conductive materials in specific proportions, or the spraying / electroplating of conductive materials onto the surface of flexible materials. The success rate of fabrication is low, often resulting in sensors that are non-conductive or not fully conductive, exhibiting poor stability and a tendency to fail after a period of use. In contrast, pneumatic tactile sensors, which utilize changes in air pressure to sense tactile information, have a simple manufacturing process, strong robustness, and are less prone to failure.

[0004] Therefore, there is a need for a chamber-type three-dimensional contact force sensor that is simple to manufacture and whose shape and structure are designed based on a mathematical model of the linear response of its internal air pressure to external force, so as to detect three-dimensional force and ensure good sensor performance. Summary of the Invention

[0005] This invention proposes a gas chamber type three-dimensional contact force sensor, which has three-dimensional force detection capability, simple preparation process, low manufacturing cost, low requirements for operating environment, and is suitable for mass production.

[0006] The present invention adopts the following technical solution.

[0007] A three-dimensional contact force sensor of the air chamber type is provided. The base plate of the air chamber type three-dimensional contact force sensor is provided with multiple air pressure sensors placed in a sealed soft air chamber. The soft air chamber is formed by an elastic contact body shell (4) located on the base plate and above or beside the air pressure sensor. When the elastic contact body shell deforms under the action of external three-dimensional force, the soft air chamber of the air pressure sensor at the force-bearing part deforms accordingly and causes the air pressure inside the soft air chamber to change. The air chamber type three-dimensional contact force sensor processes the air pressure data of the soft air chamber measured by each air pressure sensor to obtain external three-dimensional force information.

[0008] The bottom plate of the air chamber type three-dimensional contact force sensor is uniformly provided with four air pressure sensors and four soft air chambers, namely the first air pressure sensor (21) in the first soft air chamber (11), the second air pressure sensor (22) in the second soft air chamber (12), the third air pressure sensor (23) in the third soft air chamber (13), and the fourth air pressure sensor (24) in the fourth soft air chamber (14). The bottom of the elastic contact body shell is flush with the bottom of the four air pressure sensors to completely cover the air pressure sensors.

[0009] The soft air chamber is a cylindrical cavity, and the cavity space is much smaller than the volume of the elastic contact body shell.

[0010] The outer shell of the elastic contact body is molded from a cured silicone rubber material with strong adhesion and sealing properties, and the curing temperature of the silicone rubber material is room temperature.

[0011] The bottom surface of the chip portion of the pressure sensor is soldered to the circuit board (3) on the base plate, and the rest of the outer surface of the pressure sensor is completely covered by the elastic contact body shell material.

[0012] The main body of the soft air chamber is a cylindrical groove at the bottom of the elastic contact body shell. The bottom of the cylindrical groove is connected to the air pressure detection port at the top of the air pressure sensor, forming a sealed structure.

[0013] The multiple pressure sensors are located on the surface of the circuit board on the base plate and are arranged in a 90° rotation around the center point.

[0014] The preparation process of the elastic contact body shell includes the following steps:

[0015] Step S1: Assemble the lower mold after applying the release agent evenly; pour the diluted silicone rubber into the lower mold;

[0016] Step S2: Place it in the air to cure naturally for about 48 hours. After solidification, remove part of the lower mold to obtain a semi-finished product of the force sensor.

[0017] Step S3: Pour the diluted silicone rubber (8) into the upper mold (9) which is evenly coated with release agent;

[0018] Step S4: Place the semi-finished sensor upside down into the upper mold;

[0019] Step S5: Place it in the air to cure naturally for about 48 hours. After solidification, remove all molds to obtain the finished tactile sensor.

[0020] The mold is made of resin material and is formed by 3D printing.

[0021] When the air chamber type three-dimensional contact force sensor is working, it obtains three-dimensional force information by decoupling the air pressure measurement data of each air pressure sensor based on a sensor model with a cylindrical soft air chamber structure. The specific method is expressed by the following formula:

[0022]

[0023] in, , and These represent the forces acting on the miniature pressure sensor in the x, y, and z directions, respectively. , , and These represent the pressure changes in the four soft air chambers. , , , and , , , These are calibration coefficients;

[0024] The sensor model with the cylindrical soft air chamber structure was derived from experimental data obtained through finite element simulation analysis. The three-dimensional force on the model and the air pressure change in the soft air chamber are linearly related.

[0025] Compared with existing technologies, the air-chamber type three-dimensional contact force sensor proposed in this embodiment has the following advantages:

[0026] 1. Simple manufacturing process: The manufacturing process of the sensor proposed in this embodiment is simple. The mold used is made by a very mature and reliable 3D printing technology, and the elastic contact body shell is obtained by casting silicone rubber. The manufacturing process is very simple and the cost is low.

[0027] 2. Good linearity: The sensor model with a cylindrical soft air chamber structure proposed in this embodiment has shown a linear relationship between three-dimensional force and air pressure change through finite element simulation analysis and experiments. Therefore, the air chamber sensor proposed in this embodiment has good linearity and a small static coupling rate.

[0028] In this invention, the three-dimensional force is converted into a downward vector. Since the soft air chamber is a cylindrical cavity, the cavity space is much smaller than the volume of the elastic contact body shell. Therefore, it can better eliminate the error when the elastic material is deformed, and form a good linear relationship between the three-dimensional force and the change of air pressure. Attached Figure Description

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0030] Appendix Figure 1 This is a schematic diagram of the structure of a gas chamber type three-dimensional contact force sensor according to an embodiment of the present invention;

[0031] Appendix Figure 2 This is a cross-sectional schematic diagram of a gas chamber type three-dimensional contact force sensor according to an embodiment of the present invention;

[0032] Appendix Figure 3 This is a schematic diagram of the fabrication process of the air-chamber type three-dimensional contact force sensor in an embodiment of the present invention;

[0033] Appendix Figure 4 This is a schematic diagram illustrating the measurement principle of the present invention;

[0034] In the figure: circuit board (3), elastic contact shell (4), diluted silicone rubber (8), upper mold (9);

[0035] First soft air chamber (11), first air pressure sensor (21), second soft air chamber (12), second air pressure sensor (22), third soft air chamber (13), third air pressure sensor (23), fourth soft air chamber (14), fourth air pressure sensor (24). Detailed Implementation

[0036] As shown in the figure, a chamber-type three-dimensional contact force sensor is provided. The base plate of the chamber-type three-dimensional contact force sensor is provided with multiple air pressure sensors placed in a sealed soft air chamber. The soft air chamber is formed by an elastic contact body shell 4 located on the base plate and above or beside the air pressure sensor. When the elastic contact body shell deforms under the action of an external three-dimensional force, the soft air chamber of the air pressure sensor at the force-bearing part deforms accordingly, causing a change in air pressure inside the soft air chamber. The chamber-type three-dimensional contact force sensor processes the air pressure data of the soft air chamber measured by each air pressure sensor to obtain external three-dimensional force information.

[0037] The base plate of the air chamber type three-dimensional contact force sensor is uniformly provided with four air pressure sensors and four soft air chambers, namely the first air pressure sensor 21 in the first soft air chamber 11, the second air pressure sensor 22 in the second soft air chamber 12, the third air pressure sensor 23 in the third soft air chamber 13, and the fourth air pressure sensor 24 in the fourth soft air chamber 14. The bottom of the elastic contact body shell is flush with the bottom of the four air pressure sensors to completely cover the air pressure sensors.

[0038] The soft air chamber is a cylindrical cavity, and the cavity space is much smaller than the volume of the elastic contact body shell.

[0039] The outer shell of the elastic contact body is molded from a cured silicone rubber material with strong adhesion and sealing properties, and the curing temperature of the silicone rubber material is room temperature.

[0040] The bottom surface of the chip portion of the pressure sensor is soldered to the circuit board 3 on the base plate, and the rest of the outer surface of the pressure sensor is completely covered by the elastic contact body shell material.

[0041] The main body of the soft air chamber is a cylindrical groove at the bottom of the elastic contact body shell. The bottom of the cylindrical groove is connected to the air pressure detection port at the top of the air pressure sensor, forming a sealed structure.

[0042] The multiple pressure sensors are located on the surface of the circuit board on the base plate and are arranged in a 90° rotation around the center point.

[0043] The preparation process of the elastic contact body shell includes the following steps:

[0044] Step S1: Assemble the lower mold after applying the release agent evenly; pour the diluted silicone rubber into the lower mold;

[0045] Step S2: Place it in the air to cure naturally for about 48 hours. After solidification, remove part of the lower mold to obtain a semi-finished product of the force sensor.

[0046] Step S3: Pour the diluted silicone rubber 8 into the upper mold 9, which is evenly coated with release agent;

[0047] Step S4: Place the semi-finished sensor upside down into the upper mold;

[0048] Step S5: Place it in the air to cure naturally for about 48 hours. After solidification, remove all molds to obtain the finished tactile sensor.

[0049] The mold is made of resin material and is formed by 3D printing.

[0050] When the air chamber type three-dimensional contact force sensor is working, it obtains three-dimensional force information by decoupling the air pressure measurement data of each air pressure sensor based on a sensor model with a cylindrical soft air chamber structure. The specific method is expressed by the following formula:

[0051]

[0052] in, , and These represent the forces acting on the miniature pressure sensor in the x, y, and z directions, respectively. , , and These represent the pressure changes in the four soft air chambers 11, 12, 13, and 14, respectively. , , , and , , , These are calibration coefficients;

[0053] The sensor model with the cylindrical soft air chamber structure was derived from experimental data obtained through finite element simulation analysis. The three-dimensional force on the model and the air pressure change in the soft air chamber are linearly related.

[0054] In this example, the lower mold is assembled from lower mold a, lower mold b, and lower mold c.

[0055] Taking the soft air chamber 1 as an example, when the relevant part of the elastic contact body shell is subjected to pressure, the elastic contact body shell is squeezed and deformed, causing the volume of the soft air chamber 1 to decrease, which in turn causes a change in the internal air pressure. The force information of the sensor is obtained by reading the relative change in air pressure value.

Claims

1. A chamber-type three-dimensional contact force sensor, characterized in that: The base plate of the air chamber type three-dimensional contact force sensor is provided with multiple air pressure sensors placed in a sealed soft air chamber; the soft air chamber is formed by an elastic contact body shell (4) located on the base plate and above or beside the air pressure sensor; when the elastic contact body shell deforms under the action of external three-dimensional force, the soft air chamber of the air pressure sensor at the force-bearing part deforms accordingly and causes the air pressure inside the soft air chamber to change; the air chamber type three-dimensional contact force sensor processes the air pressure data of the soft air chamber measured by each air pressure sensor to obtain external three-dimensional force information; The soft air chamber is a cylindrical cavity, and the cavity space is much smaller than the volume of the elastic contact body shell; it converts the three-dimensional contact force into a downward vector; The soft air chamber is a vertically shaped, thin tubular chamber with a diameter much smaller than its height and a diameter much smaller than the thickness of the elastic contact body shell. The top of the chamber is adjacent to the top of the air chamber type three-dimensional contact force sensor; the sidewalls of the chamber are far away from the sidewalls of the air chamber type three-dimensional contact force sensor. When the air chamber type three-dimensional contact force sensor is working, it obtains three-dimensional force information by decoupling the air pressure measurement data of each air pressure sensor based on a sensor model with a cylindrical soft air chamber structure. The specific method is expressed by the following formula: in, , and These represent the forces acting on the miniature pressure sensor in the x, y, and z directions, respectively. , , and These represent the pressure changes in the four soft air chambers. , , , and , , , These are calibration coefficients; The sensor model with the cylindrical soft air chamber structure was derived from experimental data obtained through finite element simulation analysis. The three-dimensional force and the air pressure change in the soft air chamber in the model have a linear relationship. The bottom plate of the air chamber type three-dimensional contact force sensor is uniformly provided with four air pressure sensors and four soft air chambers, namely the first air pressure sensor (21) in the first soft air chamber (11), the second air pressure sensor (22) in the second soft air chamber (12), the third air pressure sensor (23) in the third soft air chamber (13), and the fourth air pressure sensor (24) in the fourth soft air chamber (14). The bottom of the elastic contact body shell is flush with the bottom of the four air pressure sensors to completely cover the air pressure sensors. The main body of the soft air chamber is a cylindrical groove at the bottom of the elastic contact body shell. The bottom of the cylindrical groove is connected to the air pressure detection port at the top of the air pressure sensor, forming a sealed structure.

2. The air-chamber type three-dimensional contact force sensor according to claim 1, characterized in that: The outer shell of the elastic contact body is molded from a cured silicone rubber material with strong adhesion and sealing properties, and the curing temperature of the silicone rubber material is room temperature.

3. The air-chamber type three-dimensional contact force sensor according to claim 1, characterized in that: The bottom surface of the chip portion of the pressure sensor is soldered to the circuit board (3) on the base plate, and the rest of the outer surface of the pressure sensor is completely covered by the elastic contact body shell material.

4. A chamber-type three-dimensional contact force sensor according to claim 1, characterized in that: The multiple pressure sensors are located on the surface of the circuit board on the base plate and are arranged in a 90° rotation around the center point.

5. A chamber-type three-dimensional contact force sensor according to claim 1, characterized in that: The preparation process of the elastic contact body shell includes the following steps: Step S1: Assemble the lower mold after applying the release agent evenly; pour the diluted silicone rubber into the lower mold; Step S2: Allow to cure naturally in the air for approximately 48 hours. After solidification, remove part of the lower mold to obtain a semi-finished product of the force sensor. Step S3: Pour the diluted silicone rubber (8) into the upper mold (9) which is evenly coated with release agent; Step S4: Place the semi-finished sensor upside down into the upper mold; Step S5: Place it in the air to cure naturally for about 48 hours. After solidification, remove all molds to obtain the finished tactile sensor.

6. A chamber-type three-dimensional contact force sensor according to claim 5, characterized in that: The mold is made of resin material and is formed by 3D printing.

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