CN115307787B - High-sensitivity split type flexible force sensor - Google Patents

Abstract

The invention discloses a high-sensitivity split type flexible force sensor. The flexible measuring device is mainly formed by combining an upper polar plate, a flexible measuring unit and a lower polar plate from top to bottom, wherein the upper polar plate and the lower polar plate are both formed by double-finger U-shaped clamps; copper electrodes are arranged on the bottom surfaces of the two fingers of the upper polar plate double-finger U-shaped clamp and the top surfaces of the two fingers of the lower polar plate double-finger U-shaped clamp as sensing electrodes; four sealed cavities of central symmetry interval array are opened inside the flexible measuring unit, and each sealed cavity is formed by an inner cavity and an outer cavity along the diagonal, and a partition exists between the inner cavity and the outer cavity so that the inner cavity and the outer cavity are communicated only at the bottom. The invention adopts a split structure, the four inner chambers realize the force-sensitive deformation function, the four outer chambers and the sensing electrode realize the capacitance sensing function, and the large measuring range and the high sensitivity of the flexible force sensor are ensured.

Description

A high-sensitivity split flexible force sensor

Technical Field

The invention relates to a flexible force sensor in the technical field of sensors, and in particular to a high-sensitivity split-type flexible force sensor.

Background Art

Touch is one of the main senses in normal human life, providing humans with information such as contact force, geometric morphology, surface material, texture, hardness, temperature, etc. In the fields of intelligent prostheses and mechanical exoskeletons, artificial tactile perception systems are often used in human neural feedback control systems to provide external environmental information for underlying control to improve the dexterity of prostheses. Tactile force is the most critical information in tactile function. Therefore, the development of flexible force sensors with high-performance tactile perception is a key technology to realize the intelligence of intelligent prostheses and mechanical exoskeletons. Capacitive sensors have become one of the main ways to realize flexible force sensors due to their fast response, low cost, and high stability.

In recent years, many studies on flexible force sensors based on capacitive sensors have been carried out at home and abroad, and have gradually been applied to the reconstruction of tactile force functions of intelligent prosthetic hands. However, the following key points and problems have been constantly highlighted during use:

1) Through the use of flexible materials, the flexural strength and tensile properties of flexible force sensors are improved, but the current mainstream flexible force sensor structure embeds rigid metal sensor elements such as copper into flexible materials, which directly leads to a decrease in the flexural strength and tensile properties of the flexible force sensor. The stress concentration at the interface between the rigid sensor element and the flexible material will increase the risk of sensor damage.

2) Capacitive flexible force sensors generally achieve capacitance changes by changing the distance between the plates. To ensure the high sensitivity of the sensor, the distance between the plates should be kept within a small range. The sensing electrodes of mainstream flexible force sensors are embedded in the force-sensitive unit. When the tactile force in the form of pressure is large, the reduction in the distance between the capacitor plates may cause the upper and lower sensing electrodes of the capacitor to be in direct contact, and the capacitor will be saturated and unable to detect changes in capacitance. On the other hand, when the tactile force in the direction of shear force is large, the increase in the distance between the sensing electrodes directly leads to a small capacitance, which is easily obliterated by interference signals in the detection of weak signals.

Summary of the invention

In order to solve the problems existing in the background technology, the purpose of the present invention is to provide a highly sensitive split flexible force sensor. The present invention adopts a split structure, multiple inner chambers realize the force-sensitive deformation function, and multiple outer chambers and sensing electrodes realize the capacitive sensing function, which ensures the large measurement range and high sensitivity of the flexible force sensor.

The technical solution adopted by the present invention to solve its technical problem is:

It is mainly composed of an upper electrode plate, a flexible measuring unit and a lower electrode plate from top to bottom. The upper electrode plate and the lower electrode plate are mainly composed of a double-finger U-shaped clamp. The bottom surfaces of the two fingers of the double-finger U-shaped clamp of the upper electrode plate are each provided with a copper electrode as the upper sensing electrode of the capacitor, and the top surfaces of the two fingers of the double-finger U-shaped clamp of the lower electrode plate are each provided with a copper electrode as the lower sensing electrode of the capacitor; four closed cavities arranged in a centrally symmetrical array are opened inside the flexible measuring unit, and each closed cavity is composed of an inner chamber and an outer chamber of exactly the same size and height along the diagonal line, and the length and width of the inner chamber and the outer chamber are equal to the finger width of the double-finger U-shaped clamp of the upper electrode plate and the lower electrode plate. There is a partition between the inner chamber and the outer chamber so that they are only connected at the bottom, in a semi-connected state.

When no external force is applied, the inner chamber of the flexible measuring unit is filled with water, and the upper half of the outer chamber is filled with air and the lower half is filled with water.

The closed cavity inside the flexible measuring unit is first evacuated, and then water is injected into the inner cavity and air is injected into the outer cavity. Due to the combined effects of the gravity of the water, the pressure of the air and the surface tension of the liquid, when no external force is applied, the inner cavity will be filled with water, the upper half of the outer cavity will be filled with air, and the lower half will be filled with water.

The top surface of the flexible measuring unit is provided with a protrusion for contacting and sensing external force between the double-finger U-shaped clamps of the upper electrode plate.

A double-finger U-shaped clip for accommodating the upper electrode and a strip groove for the upper sensing electrode are provided on the top surface of the flexible measuring unit where the upper electrode is arranged, and a double-finger U-shaped clip for accommodating the lower electrode and a strip groove for the lower sensing electrode are provided on the bottom surface of the flexible measuring unit where the lower electrode is arranged.

The two fingers of the upper plate double-finger U-shaped clamp and the two fingers of the lower plate double-finger U-shaped clamp are arranged perpendicularly, and the four closed cavity arrays are arranged to form a 2*2 row and column array. The two fingers of the upper plate double-finger U-shaped clamp are located directly above the outer chambers of the closed chambers in the two rows, and the two fingers of the lower plate double-finger U-shaped clamp are located directly below the outer chambers of the closed chambers in the two columns.

The upper electrode plate and the lower electrode plate are both processed by 3D printing technology and are made of plastic; the flexible measuring unit is made of silicone rubber material.

Each outer chamber, the upper sensing electrode above it and the lower sensing electrode below it form a capacitor unit, and four outer chambers, the upper sensing electrode and the lower sensing electrode form four capacitor units;

When the tactile force acts on the protrusion of the trapezoidal structure on the upper surface of the flexible measuring unit in the form of positive pressure, tension or shear force, the tactile force is transmitted to the four closed cavities, causing the four inner chambers to undergo compression or tension deformation, resulting in the water in the inner chamber to flow under pressure, which in turn drives the height of the water and air in the outer chamber to change, causing the dielectric ratio in the four capacitor units to change, thereby causing the capacitance of the four capacitor units to change in proportion to the tactile force, and this change is used to achieve tactile force detection.

The dielectric material specifically refers to water and air.

The two upper sensing electrodes of the capacitor are S1 and S2; the two lower sensing electrodes of the capacitor are S3 and S4. The inner chambers of the square are A1, A2, A3, A4, and the corresponding outer chambers are B1, B2, B3, B4.

In a specific implementation, when the tactile force acts on the trapezoidal structure of the flexible measuring unit in the form of pressure, the four inner chambers undergo the same compression deformation, and the height is reduced by Δd _z , causing the water in the four inner chambers to flow into the four outer chambers under the action of pressure. Since the sensing electrodes of the four capacitor units have a fixed spacing, the four outer chambers cannot produce deformation. Therefore, the water flowing into the outer chamber under the action of pressure causes the proportion of the space occupied by the air in the outer chamber to decrease, and the proportion of the space occupied by water to increase, which is manifested as the height of the air between the sensing electrodes of the capacitor unit is reduced to d _a -Δd _z , and the height of the water is increased to d _w +Δd _z . Since the dielectric ratio between the sensing electrodes of the capacitor unit changes, the capacitance of the four capacitor units produces a change related to the deformation amount Δd _z of the inner chamber.

When the tactile force acts on the trapezoidal structure of the flexible measurement unit in the form of tension, the four inner chambers undergo the same tensile deformation Δd _z , and the water in the four outer chambers flows into the four inner chambers under the action of negative pressure. Between the sensing electrodes of the capacitor unit, the height of the air increases by d _a +Δd _z , and the height of the water decreases by d _w -Δd _z . The capacitance of the four capacitor units changes in correlation with the deformation of the inner chamber Δd _z .

When the tactile force acts on the trapezoidal structure of the flexible measuring unit in the form of shear force, the shear force can be decomposed into _Fx and _Fy , where _Fx causes the inner chambers A3 and A4 to produce compressive deformation, the height is reduced by _Δdx , the inner chambers A1 and A2 to produce tensile deformation, the height is increased by _Δdx , the water in the inner chambers A3 and A4 flows into the outer chambers B3 and B4 under pressure, the water level height of the outer chambers B3 and B4 is adjusted to _dw + _Δdx , and the air height is adjusted to d _a - _Δdx , the water in the outer chambers B1 and B2 flows into the inner chambers A1 and A2 under negative pressure, the water level height of the outer chambers B1 and B2 is adjusted to _dw - _Δdx , and the air height is adjusted to d _a + _Δdx ; _Fy causes the water level height of the outer chambers B1 and B4 to be adjusted to _dw + _Δdy , the air height is adjusted to d _a - _Δdy , and the water level height of the outer chambers B2 and B3 is adjusted to dw _. -Δd _y , the air height is adjusted to _da +Δd _y .

Under the combined action of _Fz , _Fx and _Fy , the water level of the outer chamber B1 is adjusted to _dw + _Δdz - _Δdx + _Δdy , and the air height is adjusted to da _{- Δdz} + _Δdx - _Δdy , the water level of the outer chamber B2 is adjusted to _dw + _Δdz - _Δdx - _Δdy , and the air height is adjusted to da _{- Δdz} + _Δdx + _Δdy , the water level of the outer chamber B3 is adjusted to _dw + _Δdz + _Δdx - _Δdy , and the air height is adjusted to da _{- Δdz} - _Δdx + _Δdy , the water level of the outer chamber B4 is adjusted to _dw + _Δdz + _Δdx + _Δdy , and the air height is adjusted to da _{- Δdz} - _Δdx - _Δdy . At this time, the capacitance of the four capacitor units changes in correlation with the inner chamber deformation amounts _Δdz , _Δdx and _Δdy .

The height of the trapezoidal platform structure on the upper surface of the flexible measuring unit is equal to the distance from the center of the flexible measuring unit to the midpoint of the inner chamber, and the bottom surface area just covers the four inner chambers.

By solving the proportional relationship between the capacitance of the four capacitor units and the forward pressure, tension and shear force measured by the sensor, three-dimensional pressure measurement can be achieved by detecting the specific value of the capacitance in real time.

In the structure of the present invention, the four capacitor units are centrally symmetrically distributed, and the external force can be easily decomposed into X-Y-Z three-dimensional pressure and shear force. The present invention adopts a split structure, and the force-sensitive deformation function and the capacitive sensing function are respectively realized by different mechanisms, ensuring a larger measurement range and higher sensitivity of the flexible force sensor.

The present invention has the following beneficial effects:

1) A split structure is adopted to combine the rigid metal sensor element and the flexible measurement unit in the form of assembly. The rigid metal sensor element does not participate in the force-sensitive deformation process of the sensor, which greatly improves the tensile performance of the flexible force sensor. During repeated bending, the durability of the sensor is also greatly improved.

2) The four inner chambers complete the force-sensitive deformation function of the flexible force sensor, and the four capacitor units composed of the four outer chambers and the sensing electrodes realize the capacitive sensing function of the flexible force sensor. The capacitor unit does not deform, and the upper and lower sensing electrodes remain constant at a small distance. Regardless of the size of the tactile force, the capacitance can be maintained at a large change value, and neither capacitor saturation nor capacitance signal annihilation will occur, which greatly improves the measurement range and sensitivity of the flexible force sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the sensor structure of the present invention.

FIG. 2 is a schematic diagram of the structure of the sensor of the present invention.

Fig. 3 is a cross-sectional view of the sensor of the present invention taken along line A-A'.

FIG. 4 is a front view of the flexible measuring unit of the sensor of the present invention.

Fig. 5 is a cross-sectional view of the flexible measuring unit A-A' of the sensor of the present invention.

FIG. 6 is a schematic diagram of the pressure measurement principle of the sensor of the present invention.

FIG. 7 is a schematic diagram showing the tension measurement principle of the sensor of the present invention.

FIG8 is a schematic diagram showing the shear force measurement principle of the sensor of the present invention.

In the figure: 1. upper electrode, 2. flexible measuring unit, 3. lower electrode, 4. upper sensing electrode, 5. lower sensing electrode, 6. water, 7. air, 8. inner chamber, 9. outer chamber.

DETAILED DESCRIPTION

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The specific implementation of the device is shown in Figures 1, 2 and 3, and is mainly composed of an upper electrode plate 1, a flexible measurement unit 2 and a lower electrode plate 3 from top to bottom, and the upper electrode plate 1 and the lower electrode plate 3 are respectively located above and below the flexible measurement unit 2;

The upper electrode plate 1 and the lower electrode plate 3 are mainly composed of a double-finger U-shaped clamp, which is composed of two fingers arranged in parallel at intervals and connected at the root end;

The two fingers of the double-finger U-shaped clip of the upper electrode plate 1 are respectively located on both sides above the flexible measuring unit 2. The bottom surfaces of the two fingers of the double-finger U-shaped clip of the upper electrode plate 1 are each provided with a copper electrode of the same width as the finger as the sensing electrode 4 of the capacitor. The double-finger U-shaped clip has two fingers, and therefore has two sensing electrodes 4.

The two fingers of the double-finger U-shaped clamp of the lower electrode plate 3 are respectively located on both sides below the flexible measuring unit 2. The top surfaces of the two fingers of the double-finger U-shaped clamp of the lower electrode plate 3 are each provided with a copper electrode of the same width as the finger as the lower sensing electrode 5 of the capacitor. The double-finger U-shaped clamp has two fingers, and therefore has two lower sensing electrodes 5.

The flexible measuring unit 2 has four closed cavities arranged in a centrally symmetrical array, and the four inner chambers are arranged in a field-shaped pattern to realize the force-sensitive deformation function of the flexible force sensor. Each closed cavity is composed of a square inner chamber 8 (A1, A2, A3, A4) and an outer chamber 9 (B1, B2, B3, B4) of exactly the same size and height along its own diagonal. The length and width of the inner chamber 8 and the outer chamber 9 are equal to the finger width of the upper plate 1 and the lower plate 3 double-finger U-shaped clamp. There is a partition between the inner chamber 8 and the outer chamber 9 so that they are only connected at the bottom, in a semi-connected state. The inner chamber 8 and the outer chamber 9 are connected at the bottom through a radial channel along the diagonal.

When no external force is applied, the inner chamber 8 in the flexible measuring unit 2 is filled with water 6 , and the upper half of the outer chamber 9 is filled with air 7 and the lower half is filled with water 6 .

As shown in Figures 1 and 4, the upper electrode plate 1 is a double-finger U-shaped clip processed by 3D printing technology. The material is plastic and is not easy to deform after processing. Two copper electrodes with the same width as the fork fingers are distributed on the upper inner surface, serving as the two upper sensing electrodes 4 of the capacitor, namely S1 and S2 in the figure.

A double-finger U-shaped clip for accommodating the upper electrode plate 1 and a strip groove for embedding the upper electrode plate 1 and the upper sensing electrode 4 are provided on the top surface of the flexible measuring unit 2 where the upper electrode plate 1 is arranged, and a double-finger U-shaped clip for accommodating the lower electrode plate 3 and a strip groove for embedding the lower sensing electrode 5 are provided on the bottom surface of the flexible measuring unit 2 where the lower electrode plate 3 is arranged.

As shown in Figures 1 to 3, two strip grooves as wide as fingers are distributed horizontally on the upper surface of the flexible measuring unit 2, and each strip groove is embedded in a finger of the upper electrode 1 and an upper sensing electrode 4; two strip grooves as wide as fingers are distributed vertically on the lower surface, and each strip groove is embedded in a finger of the lower electrode 3 and a lower sensing electrode 5; a trapezoidal platform structure for tactile force detection is provided as a protrusion in the center of the upper surface of the flexible measuring unit 2.

As shown in Fig. 3, Fig. 6 and Fig. 7, the flexible measuring unit 2 is made of silicone rubber, and there are four closed cavities arranged in a centrosymmetric array inside the unit. Each closed cavity is composed of a square inner chamber 8 (A1, A2, A3, A4) and an outer chamber 9 (B1, B2, B3, B4) of exactly the same size and height along the diagonal line. The width of the inner and outer chambers is the same as the width of the fork fingers, and there is a partition between them. They are only connected at the bottom, which is a semi-connected state; each closed cavity is first evacuated, and then water 6 is filled from the inner chamber 8 and air 7 is filled from the outer chamber 9 by injection. Due to the combined effect of the gravity of the water, the pressure of the air and the surface tension of the liquid, when no external force is applied, the inner chamber 8 will be filled with water 6 to a height of d, the upper half of the outer chamber 9 will be filled with air to a height of d _a , and the lower half will be filled with water to a height of d _w . Two strip grooves as wide as the fork fingers are distributed horizontally on the upper surface of the flexible measuring unit 2, and two strip grooves as wide as the fork fingers are distributed vertically on the lower surface, both of which are used for subsequent assembly. A trapezoidal platform structure for tactile force detection is provided in the center of the upper surface. The height is L, which is equal to the distance from the center of the flexible measuring unit to the midpoint of the inner cavity, and the bottom area just covers the four inner cavities 8.

As shown in FIG. 1 and FIG. 5 , the lower electrode plate 3 is also a double-finger U-shaped clip, and two copper electrodes with the same width as the fork fingers are distributed on the lower inner surface, serving as the two lower sensing electrodes 5 of the capacitor, namely S3 and S4 in the figure.

As shown in Figures 1, 2 and 3, the two fingers of the two-finger U-shaped clamp of the upper electrode plate 1 and the two fingers of the two-finger U-shaped clamp of the lower electrode plate 3 are arranged perpendicularly, and the four closed cavity arrays are arranged to form a 2*2 row and column array, and the two fingers of the two-finger U-shaped clamp of the upper electrode plate 1 are respectively located directly above the outer chambers 9 of the closed cavities in the two rows, and the two fingers of the two-finger U-shaped clamp of the lower electrode plate 3 are respectively located directly below the outer chambers 9 of the closed cavities in the two columns.

The upper electrode plate 1 is inserted horizontally along the strip groove on the upper surface of the flexible measuring unit 2, and the lower electrode plate 3 is inserted vertically along the strip groove on the lower surface of the flexible measuring unit 2. The flexible measuring unit 2 is sandwiched by the upper electrode plate 1 and the lower electrode plate 3 in a sandwich structure; since the upper sensing electrode 4 is distributed horizontally and the lower sensing electrode 5 is distributed vertically, there are four square overlapping parts, and the four outer chambers 9 are completely covered to form four capacitor units, thereby realizing the capacitive sensing function of the flexible force sensor.

The upper and lower plates are made of plastic materials, which are not easily deformed under pressure, so the distance between the sensing electrodes of the four capacitor units is fixed. In the initial state, the capacitance of the four capacitor units can be expressed as:

Wherein, _Cw represents the capacitance value of the portion of the capacitor unit in which the dielectric is water, _Ca represents the capacitance value of the portion of the capacitor unit in which the dielectric is air, and _Cpi represents the capacitance value of the portion of the capacitor unit in which the dielectric is a flexible material, wherein:

Among them, ε ₀ represents the dielectric constant of vacuum, ε _w represents the dielectric constant of water, ε _a represents the dielectric constant of air, ε _pi represents the dielectric constant of flexible material, w is the width of sensing electrode, d _w is the height of water, d _a is the height of air, h is the thickness of flexible material in capacitor unit. Substituting equation (2-4) into equation (1), we can get:

As shown in FIG3 and FIG7, the four inner chambers 8 are arranged in a field shape to realize the force-sensitive deformation function of the flexible force sensor. When the tactile force acts on the trapezoidal structure of the flexible measurement unit 2 in the form of pressure, the four inner chambers 8 undergo the same compression deformation, and the height is reduced by Δd _z . The relationship between the deformation amount and the pressure can be expressed as:

F _z = EΔd _z (6)

Where E represents the Young's modulus of the flexible measurement unit in the Z direction.

The water 6 in the four inner chambers 8 flows into the four outer chambers 9 under pressure. Since the distance between the sensing electrodes of the four capacitor units is fixed, the four outer chambers 9 cannot be deformed. Therefore, the water flowing into the outer chambers 9 under pressure causes the space ratio of the air 7 in the outer chamber 9 to decrease, and the space ratio of the water 6 to increase. This is manifested as the height of the air 7 between the sensing electrodes of the capacitor unit is reduced to d _a -Δd _z , and the height of the water is increased to d _w +Δd _z . Since the dielectric ratio between the sensing electrodes of the capacitor unit changes, the capacitance of the four capacitor units changes as follows:

When the tactile force acts on the trapezoidal structure of the flexible measuring unit 2 in the form of a pulling force, the four inner chambers 8 undergo the same pulling deformation, and the relationship between the deformation amount and the pressure can be expressed as:

F _z = EΔd _z (8)

The water 6 in the four outer chambers 9 flows into the four inner chambers 8 under the negative pressure. The height of the air 7 between the sensing electrodes of the capacitor unit increases to d _a +Δd _z , and the height of the water 6 decreases to d _w -Δd _z . Since the dielectric ratio between the sensing electrodes of the capacitor unit changes, the capacitance of the four capacitor units changes to:

When the tactile force acts on the trapezoidal structure of the flexible measuring unit 2 in the form of shear force, the shear force can be decomposed into _Fx and _Fy , where _Fx causes the inner chambers A3 and A4 to produce compression deformation, the height is reduced by _Δdx , and the inner chambers A1 and A2 to produce tensile deformation, the height is increased by _Δdx . The relationship between the deformation _Δdx and the shear force _Fx in the X direction can be expressed as:

Where G is the shear elastic modulus and L is the height of the trapezoidal platform.

The water in the inner chambers A3 and A4 flows into the outer chambers B3 and B4 under pressure, the water level heights of the outer chambers B3 and B4 are adjusted to _dw + _Δdx , and the air height is adjusted to d _{a -Δdx} . The water in the outer chambers B1 and B2 flows into the inner chambers A1 and A2 under negative pressure, the water level heights of the outer chambers B1 and B2 are adjusted to _{dw -Δdx} , and the air height is adjusted to d _a + _Δdx .

Similarly, _Fy causes the water level of the outer chambers B1 and B4 to be adjusted to _dw + _Δdy , and the air level to be adjusted to da _{- Δdy} . The water level of the outer chambers B2 and B3 is adjusted to _dw - _Δdy , and the air level is adjusted to _da + _Δdy . The relationship between the deformation _Δdy and the Y-direction shear force _Fy can be expressed as:

As shown in Figures 6, 7 and 8, under the combined action of pressure _Fz and shear forces _Fx and _Fy , the water level of the outer chamber B1 is adjusted to _dw + _Δdz - _Δdx + _Δdy , and the air height is adjusted to da _{- Δdz} + _Δdx - _Δdy , the water level of the outer chamber B2 is adjusted to _dw + _Δdz -Δdx _{- Δdy} , and the air height is adjusted to da _{- Δdz} + _Δdx + _Δdy , the water level of the outer chamber B3 is adjusted to _dw + _Δdz + _Δdx - _Δdy , and the air height is adjusted to da _{- Δdz} - _Δdx + _Δdy , the water level of the outer chamber B4 is adjusted to _dw + _Δdz + _Δdx + _Δdy , and the air height is adjusted to da _{- Δdz} - _Δdx - _Δdy . At this time, the capacitance of the four capacitor units is related to the deformation amounts _Δdz , _Δdx and Δd _y- related changes.

From this principle, it can be seen that the external pressure-shear force changes the height of the water and air in the outer chamber by changing the height of the four inner chambers, thereby establishing a direct connection between the capacitance change of the four capacitor units and the magnitude of the external pressure-shear force. Through the analytical equations (6), (8), (11) and (12), the relationship between the capacitance change and the external pressure-shear force can be obtained, and the measurement of three-dimensional pressure-shear force can be realized.

The present invention adopts a split structure, in which four inner chambers complete the force-sensitive deformation function of the flexible force sensor, and four capacitor units composed of four outer chambers and sensing electrodes realize the capacitive sensing function of the flexible force sensor. The capacitor units do not produce deformation, thereby ensuring a higher measurement range and sensitivity of the flexible force sensor. At the same time, considering that the rigid metal sensing element does not participate in the force-sensitive deformation process of the sensor, the tensile performance of the flexible force sensor is greatly improved, and the durability of the sensor is also greatly improved.

Claims (7)

1. A split type flexible force transducer of high sensitivity, its characterized in that:

The device mainly comprises an upper polar plate (1), a flexible measuring unit (2) and a lower polar plate (3) from top to bottom, wherein the upper polar plate (1) and the lower polar plate (3) are mainly formed by double-finger U-shaped clamps, copper electrodes are arranged on the bottom surfaces of two fingers of the double-finger U-shaped clamps of the upper polar plate (1) and serve as upper sensing electrodes (4) of a capacitor, and copper electrodes are arranged on the top surfaces of two fingers of the double-finger U-shaped clamps of the lower polar plate (3) and serve as lower sensing electrodes (5) of the capacitor;

Four sealed cavities arranged in a central symmetrical interval array are formed in the flexible measuring unit (2), each sealed cavity is formed by an inner cavity (8) and an outer cavity (9) which are identical in size and height along a diagonal line, the long widths of the inner cavity (8) and the outer cavity (9) are equal to the finger widths of the double-finger U-shaped clamps of the upper polar plate (1) and the lower polar plate (3), and a partition exists between the inner cavity (8) and the outer cavity (9) so that the two cavities are communicated only at the bottom and are in a semi-communicated state.

2. The high sensitivity split flexible force sensor of claim 1, wherein:

When no external force is received, water (6) is arranged in an inner chamber (8) in the flexible measuring unit (2), air (7) is arranged at the upper part in an outer chamber (9), and water (6) is arranged at the lower part in the outer chamber.

3. The high sensitivity split flexible force sensor of claim 1, wherein:

the top surface of the flexible measuring unit (2) is provided with a bulge for sensing external force in a contact manner between the two U-shaped clamps of the upper polar plate (1).

4. The high sensitivity split flexible force sensor of claim 1, wherein:

the top surface of the flexible measuring unit (2) provided with the upper polar plate (1) is provided with a strip-shaped groove for embedding the double-finger U-shaped clamp containing the upper polar plate (1) and the upper sensing electrode (4), and the bottom surface of the flexible measuring unit (2) provided with the lower polar plate (3) is provided with a strip-shaped groove for embedding the double-finger U-shaped clamp containing the lower polar plate (3) and the lower sensing electrode (5).

5. The high sensitivity split flexible force sensor of claim 1, wherein:

The two fingers of the upper polar plate (1) double-finger U-shaped clamp and the two fingers of the lower polar plate (3) double-finger U-shaped clamp are vertically arranged, four closed cavity arrays are arranged to form a2 x 2 row array, the two fingers of the upper polar plate (1) double-finger U-shaped clamp are respectively positioned right above the outer cavities (9) of the two rows of closed cavities, and the two fingers of the lower polar plate (3) double-finger U-shaped clamp are respectively positioned right below the outer cavities (9) of the two columns of closed cavities.

6. The high sensitivity split flexible force sensor of claim 1, wherein:

the upper polar plate (1) and the lower polar plate (3) are processed by adopting a 3D printing technology, and the materials are plastics; the flexible measuring unit (2) is made of a silicon rubber material.

7. The high sensitivity split flexible force sensor of claim 1, wherein:

Each outer chamber (9) and an upper sensing electrode (4) above the outer chamber and a lower sensing electrode (5) below the outer chamber form a capacitance unit, and four outer chambers (9) and the upper sensing electrode (4) and the lower sensing electrode (5) form four capacitance units;

When the tactile force acts on the bulge of the upper surface of the flexible measuring unit (2), the tactile force is transmitted to the four closed cavities, so that the four inner cavities (8) generate compression or pulling deformation respectively, water (6) in the inner cavities (8) flows under pressure, the heights of the water (6) and air (7) in the outer cavities (9) are further driven to change, the dielectric ratio in the four capacitance units is changed, and the capacitance of the four capacitance units generates change in proportion to the tactile force respectively.