A flexible electrostatic three-dimensional force sensor and sensor array

Abstract

The application discloses a flexible triboelectric three-dimensional force sensor and a sensing array, wherein a dome structure is provided with a convex and a base, one end of the convex is attached to one side of the base, the other side of the base is attached to one side of a first flexible base, the other side of the first flexible base is attached to one side of a first electrode, the other side of the first electrode is attached to one side of an insulating spacer layer, the other side of the insulating spacer layer is attached to one side of a three-dimensional force sensitive layer, one side of the three-dimensional force sensitive layer is provided with a hierarchical unstable microstructure, the other side of the three-dimensional force sensitive layer is attached to one side of a second electrode, the other side of the second electrode is attached to one side of a second flexible base, the three-dimensional force sensitive layer is doped with a conductive filler, the conductive filler is composed of an ionic liquid and conductive particles, and the electrode surface is sprayed with a mixture of a micro-nano conductive material and a binder. The electrode and the three-dimensional force sensitive layer are both circularly divided into fan shapes.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, specifically relating to a flexible ionized three-dimensional force sensor and sensing array. Background Technology

[0002] Currently, intelligent assembly has become the mainstream development direction of modern manufacturing. The intelligent assembly process relies on robotic arms and sensors to achieve high-precision, high-sensitivity operations to cope with increasingly complex tasks. As the execution unit of the intelligent assembly system, the robotic arm, with its powerful programmability and precise motion control capabilities, can perform a series of tasks ranging from simple handling to complex assembly. Sensors, acting as the "tentacles" for perceiving information from the external environment, are responsible for collecting and processing various physical quantities during the robotic arm's operation in real time, such as position, speed, and force, providing accurate data support for decision-making. Especially in three-dimensional force perception, high-precision sensors can capture subtle force changes during assembly, ensuring that every action is just right and avoiding damage or assembly failure due to improper force.

[0003] However, facing the growing demand for intelligent manufacturing, the limitations of traditional sensors in the field of intelligent assembly are gradually becoming apparent. Insufficient sensitivity limits the sensor's ability to capture subtle force changes, making it difficult to achieve ideal control accuracy in precision assembly; a narrow measurement range means the sensor is inadequate when dealing with large-scale force variations, limiting its application scope; and excessive interference further exacerbates data inaccuracy, affecting the stability and reliability of assembly operations. These problems combined not only increase uncertainty in the assembly process but also reduce overall production efficiency and product quality, thus hindering the further development and widespread adoption of intelligent assembly technology to some extent. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem that narrow sensor range and insufficient sensitivity prevent intelligent assembly under various working conditions, and proposes a flexible ionized three-dimensional force sensor and sensing array.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A flexible ionized three-dimensional force sensor includes a dome structure, a flexible substrate, electrodes, an insulating spacer layer, and a three-dimensional force-sensitive layer. The flexible substrate includes a first flexible substrate and a second flexible substrate. The electrodes include a first electrode and a second electrode. The dome structure has a protrusion and a substrate. One end of the protrusion is attached to one side of the substrate, and the other side of the substrate is attached to one side of the first flexible substrate. The other side of the first flexible substrate is attached to one side of the first electrode, and the other side of the first electrode is attached to one side of the insulating spacer layer. The other side of the insulating spacer layer is attached to one side of the three-dimensional force-sensitive layer. One side of the three-dimensional force-sensitive layer has a hierarchical unstable microstructure. The other side of the three-dimensional force-sensitive layer is attached to one side of the second electrode, and the other side of the second electrode is attached to one side of the second flexible substrate. The three-dimensional force-sensitive layer is doped with a conductive filler composed of ionic liquid and conductive particles. The electrode surface is sprayed with a mixture of micro / nano conductive material and binder. Both the electrode and the three-dimensional force-sensitive layer are equally divided into fan-shaped circles.

[0006] A method for fabricating a flexible ionized three-dimensional force sensor includes the following steps: sequentially attaching a dome structure, a flexible substrate, an electrode, an insulating spacer layer, and a three-dimensional force-sensitive layer in the order of protrusion, substrate, first flexible substrate, first electrode, insulating spacer layer, three-dimensional force-sensitive layer, second electrode, and second flexible substrate. The protrusions are made of a flexible polymer material doped with inorganic materials. The substrate is made of flexible polymer material; The flexible substrate is made of a flexible polymer elastomer film; The electrode is made of a polymer film with micro-nano conductive material on its surface. The electrode is prepared by mixing the micro-nano conductive material with a binder and then spraying it onto the surface of the polymer film. The three-dimensional force-sensitive layer adopts an elastomer composite film doped with conductive filler. The conductive filler and elastomer in the elastomer composite film doped with conductive filler are mixed by solvent dispersion.

[0007] Furthermore, the other side of the substrate is bonded to one side of the first flexible substrate by dispensing adhesive, and the other side of the first flexible substrate is bonded to one side of the first electrode and the other side of the second electrode is bonded to one side of the second flexible substrate by hot pressing or dispensing adhesive.

[0008] Furthermore, the inorganic material in the flexible polymer material doped with inorganic material is selected from one or more of nano-silica and hexagonal boron nitride; The flexible polymer material is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers; The flexible polymer elastomer film is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers; The micro-nano conductive material in the polymer film coated with micro-nano conductive material is selected from one or more of carbon-based conductive materials and two-dimensional inorganic compounds with metallic conductivity. The polymer film whose surface is coated with micro-nano conductive material is selected from polyethylene terephthalate film. The adhesive is styrene-butadiene rubber; The conductive filler in the doped conductive filler elastomeric composite film is composed of ionic liquid and conductive particles; The elastomer in the doped conductive filler elastomer composite film is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers.

[0009] Furthermore, the carbon-based conductive material is selected from one or more of single-layer graphene, multi-layer graphene, carbon black, single-walled carbon nanotubes, and multi-walled carbon nanotubes. The two-dimensional inorganic compound with metallic conductivity is MXene; The conductive particles are MXene; The ionic liquid is selected from one or more of poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, and 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide.

[0010] A flexible ionized three-dimensional force sensing array includes a dome structure array, a flexible substrate, an electrode array, an insulating spacer array, and a three-dimensional force-sensitive layer array. The flexible substrate includes a first flexible substrate portion and a second flexible substrate portion. The electrode array includes a first electrode array and a second electrode array. The dome structure array is provided with a protrusion array and a dome substrate. One side of the protrusion array is attached to one side of the dome substrate, and the other side of the dome substrate is attached to one side of the first flexible substrate portion. The other side of the first flexible substrate portion is attached to one side of the first electrode array, and the other side of the first electrode array is attached to one side of the insulating spacer array. The other side of the insulating spacer array is attached to one side of the three-dimensional force-sensitive layer array. One side of the three-dimensional force-sensitive layer array has a hierarchical unstable microstructure. The other side of the three-dimensional force-sensitive layer array is attached to one side of the second electrode array, and the other side of the second electrode array is attached to one side of the second flexible substrate portion. The three-dimensional force-sensitive layer array is doped with a conductive filler composed of ionic liquid and conductive particles. The surface of the electrode array is sprayed with a mixture of micro / nano conductive materials and binder.

[0011] A method for fabricating a flexible ionized three-dimensional force sensing array, comprising the following steps: sequentially attaching a dome structure array, a flexible substrate, an electrode array, an insulating spacer array, and a three-dimensional force-sensitive layer array in the order of a protrusion array, a dome substrate, a first flexible substrate portion, a first electrode array, an insulating spacer array, a three-dimensional force-sensitive layer array, a second electrode array, and a second flexible substrate portion; The protrusion array is made of a flexible polymer material doped with inorganic materials; The dome base is made of flexible polymer material; The dome structure array is made by batch-coating a flexible polymer mixture doped with inorganic materials and a flexible polymer in a dome structure array mold; The flexible substrate is made of a flexible polymer elastomer film; The electrode array uses a polymer film with micro-nano conductive material on its surface. The specific preparation method of the electrode array is as follows: the micro-nano conductive material is mixed with the binder and then sprayed onto the surface of the polymer film. The electrode array is obtained by cutting the pattern of the polymer film with micro-nano conductive material on its surface by laser etching. The three-dimensional force-sensitive layer array uses an elastomeric composite film doped with conductive filler. The specific preparation method of the three-dimensional force-sensitive layer array is as follows: an elastomeric composite film doped with conductive filler and having a hierarchical unstable microstructure is prepared by solvent dispersion and molding, and the three-dimensional force-sensitive layer array is obtained by laser etching.

[0012] Furthermore, the other side of the dome base is bonded to one side of the first flexible base portion by dispensing adhesive, and the other side of the first flexible base portion is bonded to one side of the first electrode array and the other side of the second electrode array is bonded to one side of the second flexible base portion by hot pressing or dispensing adhesive.

[0013] Furthermore, the inorganic material in the flexible polymer material doped with inorganic material is selected from one or more of nano-silica and hexagonal boron nitride; The flexible polymer material is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers; The flexible polymer elastomer film is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers; The micro-nano conductive material in the polymer film coated with micro-nano conductive material is selected from one or more of carbon-based conductive materials and two-dimensional inorganic compounds with metallic conductivity. The polymer film whose surface is coated with micro-nano conductive material is selected from polyethylene terephthalate film. The adhesive is styrene-butadiene rubber; The conductive filler in the doped conductive filler elastomeric composite film is composed of ionic liquid and conductive particles; The elastomer in the doped conductive filler elastomer composite film is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers.

[0014] Furthermore, the carbon-based conductive material is selected from one or more of single-layer graphene, multi-layer graphene, carbon black, single-walled carbon nanotubes, and multi-walled carbon nanotubes. The two-dimensional inorganic compound with metallic conductivity is MXene; The conductive particles are MXene; The ionic liquid is selected from one or more of poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, and 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This invention proposes a flexible ionized three-dimensional force sensor. The electrode surface is coated with a mixture of micro-nano conductive materials and binder, which gives the electrode surface an irregular microstructure. This microstructure works together with the hierarchical unstable microstructure on the surface of the three-dimensional force-sensitive layer to improve the sensor's sensitivity. The hierarchical unstable microstructure is an irregularly distributed uneven structure similar to sandpaper. Hierarchy refers to the inconsistent height of the uneven structure, and instability refers to the unevenness of the protrusions, for example, the diameter of the head of the protrusion is larger than that of its root. One side of the three-dimensional force-sensitive layer has a hierarchical unstable microstructure, which allows the sensor to maintain a large deformation over a wide pressure range. The three-dimensional force-sensitive layer is doped with a conductive filler composed of ionic liquid and conductive particles, which improves the sensor's sensitivity and widens its measurement range. The conductive particles increase the modulus of the three-dimensional force-sensitive layer, thus widening the measurement range of the flexible ionized three-dimensional force sensor. The ionic liquid improves the sensitivity of the flexible ionized three-dimensional force sensor, but too much ionic liquid will increase the plasticity of the ion membrane, which is not conducive to increasing the modulus of the three-dimensional force-sensitive layer, and thus hinders the widening of the sensor's measurement range. By adjusting the ionic liquid and conductive particles to achieve a balance, a highly sensitive and wide-range flexible ionized three-dimensional force sensor is obtained. By constructing hierarchical unstable microstructures on the surface of the three-dimensional force-sensitive layer, doping the three-dimensional force-sensitive layer with conductive fillers, constructing irregular microstructures on the electrode surface, and dividing the three-dimensional force-sensitive layer and electrodes into sector-shaped circular blocks, the requirements of wide range, high sensitivity, and three-dimensional force sensing are achieved. This enables application verification of intelligent assembly under various working conditions, providing solid theoretical and technical support for the development of intelligent assembly towards precision and accuracy. Experimental results show that the flexible ionized three-dimensional force sensor provided by this invention has the advantages of high sensitivity and wide range. Specifically, high sensitivity: the maximum capacitance change under normal pressure is approximately 12.5 nF, and the maximum capacitance change under tangential force is approximately 10 nF; wide range: the sensing range for normal pressure is 0.2~13.05 N, the sensing range for X-tangential force is 0.02~2.14 N, and the sensing range for Y-tangential force is 0.0~2.5 N.

[0016] This invention proposes a method for fabricating a flexible ionized three-dimensional force sensor. The electrodes are obtained by uniformly mixing micro / nano conductive materials with a binder and then spraying the mixture onto the surface of a polymer film. This results in an irregular microstructure on the electrode surface, which, together with the hierarchical unstable microstructure on the surface of the three-dimensional force-sensitive layer, enhances the sensor's sensitivity. The flexible ionized three-dimensional force sensor fabricated using this method exhibits good flexibility, a wide measurement range, and changes in the contact area between the dielectric layer and the electrode under stress, resulting in high sensitivity. It can be used to achieve precise grasping and manipulation by robotic arms under various working conditions and for intelligent assembly operations.

[0017] The present invention proposes a flexible ionized three-dimensional force sensing array. The introduction of a spacer layer can effectively disperse the stress coupling caused by the excessive Young's modulus of the material, thereby reducing crosstalk between adjacent units of the ionized sensing array.

[0018] The present invention proposes a flexible ionized three-dimensional force sensing array that can be well attached to the surface of the fingers of a robotic arm, which plays a crucial role in realizing intelligent assembly under various working conditions. Attached Figure Description

[0019] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0020] Figure 1 This is a schematic diagram of the structure of a flexible ionized three-dimensional force sensor according to the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of a flexible ionized three-dimensional force sensing array according to the present invention.

[0022] Figure 3 This is a schematic diagram of the single-point performance of a first embodiment of a flexible ionized three-dimensional force sensor of the present invention.

[0023] Figure 4 This is a schematic diagram of the dynamic response speed of a first embodiment of a flexible ionized three-dimensional force sensor according to the present invention.

[0024] Figure 5 This is a schematic diagram of a cyclic test of a first embodiment of a flexible ionized three-dimensional force sensor of the present invention.

[0025] Figure 6 This is a schematic diagram of the single-point performance of a comparative example of a flexible ionized three-dimensional force sensor of the present invention.

[0026] Figure 7 This is a schematic diagram of the single-point performance of a flexible ionized three-dimensional force sensor according to the present invention, shown in Comparative Example 2.

[0027] Figure 8 This is an illustrative diagram showing the partitioning of a three-dimensional force sensor according to a third embodiment of the flexible ionized three-dimensional force sensor of the present invention.

[0028] Figure 9 This is a schematic diagram of the positive pressure response of a third embodiment of a flexible ionized three-dimensional force sensor of the present invention.

[0029] Figure 10 This is a schematic diagram of the force response in the X direction when the normal force is 2N, according to Embodiment 3 of the flexible ionized three-dimensional force sensor of the present invention.

[0030] Figure 11This is a schematic diagram of the force response in the Y direction when the normal force is 2N, according to Embodiment 3 of the flexible ionized three-dimensional force sensor of the present invention.

[0031] Among them, the flexible ionized three-dimensional force sensor 1 includes: a protrusion 101; a substrate 102; a first flexible substrate 103; a first electrode 104; an insulating spacer layer 105; a three-dimensional force-sensitive layer 106; a second electrode 107; a second flexible substrate 108; a flexible ionized three-dimensional force-sensing array 2 including: a protrusion array 201; a dome substrate 202; a first flexible substrate portion 203; a first electrode array 204; an insulating spacer layer array 205; a three-dimensional force-sensitive layer array 206; a second electrode array 207; and a second flexible substrate portion 208. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0034] Example 1 This embodiment provides a method for fabricating a flexible ionized three-dimensional force sensor, which includes the following steps: (1) Preparation of the dome structure: PDMS was mixed at a ratio of stock solution: curing agent = 10:1. The inorganic material and the mixed PDMS were dispersed and stirred evenly. The inorganic material / PDMS mixture was then scraped onto a mold with a frustum groove, ensuring that it fully filled the groove. Subsequently, PDMS was mixed at a ratio of stock solution: curing agent = 10:1 and scraped onto the mold. Vacuum was evacuated for 30 minutes. Heating and curing were then performed to obtain the dome structure.

[0035] (2) Preparation of the first flexible substrate and the first electrode assembly: The micro-nano conductive material (MXene) and the binder (SBR) are mixed evenly and then sprayed onto the surface of a polymer film (PET). A specific electrode shape is obtained by laser etching technology. The spraying of the micro-nano conductive material (MXene) and the binder (SBR) after being mixed evenly results in an irregular microstructure on the electrode surface. Then, the first flexible substrate and the first electrode are combined by hot pressing or dispensing to finally obtain the first flexible substrate and the first electrode assembly.

[0036] (3) Preparation of the three-dimensional force-sensitive layer: The thermoplastic polyurethane elastomer was thoroughly dispersed in solvent under magnetic stirring at 80 °C. While maintaining the magnetic stirring temperature, conductive fillers (1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide and MXene) were added to the well-dispersed solution and thoroughly mixed. The thoroughly mixed solution was transferred onto a template with an anti-hierarchical unstable microstructure. Finally, the solvent was evaporated at 80 °C to obtain the three-dimensional force-sensitive layer.

[0037] (4) Preparation of the lower electrode and the lower flexible substrate assembly: The micro-nano conductive material (MXene) and the binder (SBR) are mixed evenly and then sprayed onto the surface of the polymer film (PET). A specific electrode shape is obtained by laser etching technology. The spraying of the micro-nano conductive material (MXene) and the binder (SBR) after being mixed evenly results in an irregular microstructure on the electrode surface. Then, the second flexible substrate and the second electrode are combined by hot pressing or dispensing to finally obtain the second electrode and the second flexible substrate assembly.

[0038] (5) Assembly of the flexible ionized three-dimensional force sensor: The first flexible substrate, the first electrode assembly, the insulating spacer layer, and the three-dimensional force-sensitive layer are aligned and assembled by dispensing to obtain the first flexible substrate-first electrode-insulating spacer-three-dimensional force-sensitive layer assembly. This assembly is then aligned and assembled with the second electrode and the second flexible substrate assembly by hot pressing or dispensing to obtain the first flexible substrate-first electrode-insulating spacer-three-dimensional force-sensitive layer-second electrode-second flexible substrate assembly. Finally, the dome structure is combined with the first flexible substrate by dispensing to obtain the flexible ionized three-dimensional force sensor, as shown below. Figure 1 As shown.

[0039] The single-point performance diagram of the pressure sensor is shown below. Figure 3 As shown.

[0040] See Figure 4 To evaluate the dynamic response speed of the sensor, a normal force of approximately 1.75 N was manually applied to a flexible ionized three-dimensional force sensor and then rapidly released. The results showed a response time of 12 ms and a relaxation time of 18 ms.

[0041] See Figure 5 For flexible sensors, high mechanical durability under long-term or cyclic use plays a crucial role in ensuring reliable input-output relationships. Under a peak pressure of 1.5 N, more than 8000 repeated compression / release tests were conducted, and a flexible ionized three-dimensional force sensor exhibited good capacitive response consistency during the cyclic testing period.

[0042] Comparative Example 1 This comparative example provides a flexible ionized three-dimensional force sensor, which differs from Example 1 in that the conductive filler in the three-dimensional force-sensitive layer is 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide.

[0043] The single-point performance diagram of the pressure sensor is shown below. Figure 6 As shown.

[0044] The test results of Example 1 and Comparative Example 1 show that adding MXene to the sensitive layer can broaden the measurement range of the sensor.

[0045] Comparative Example 2 This comparative example provides a flexible ionized three-dimensional force sensor, which differs from Embodiment 1 in that both the first and second electrodes are made of copper.

[0046] The single-point performance diagram of the pressure sensor is shown below. Figure 7 As shown.

[0047] The test results of Example 1 and Comparative Example 2 show that, compared with ordinary metal electrodes, the electrode with irregular microstructures on the surface designed and prepared in Example 1 can improve the sensitivity of the sensor.

[0048] Example 2 A flexible, ionized three-dimensional force sensor includes a dome structure, a flexible substrate, electrodes, an insulating spacer layer 105, and a three-dimensional force-sensitive layer 106. The flexible substrate includes a first flexible substrate 103 and a second flexible substrate 108. The electrodes include a first electrode 104 and a second electrode 107. The dome structure has a protrusion 101 and a substrate 102. One end of the protrusion 101 is attached to one side of the substrate 102, and the other side of the substrate 102 is attached to one side of the first flexible substrate 103. The other side of the first flexible substrate 103 is attached to one side of the first electrode 104, and the other side of the first electrode 104 is attached to the insulating spacer layer 106. One side of the insulating spacer layer 105 is attached to the other side of the three-dimensional force-sensitive layer 106. One side of the three-dimensional force-sensitive layer 106 has a hierarchical unstable microstructure. The other side of the three-dimensional force-sensitive layer 106 is attached to one side of the second electrode 107. The other side of the second electrode 107 is attached to one side of the second flexible substrate 108. The three-dimensional force-sensitive layer 106 is doped with a conductive filler, which is composed of ionic liquid and conductive particles. The electrode surface is sprayed with a mixture of micro-nano conductive materials and binder. Both the electrode and the three-dimensional force-sensitive layer 106 are equally divided into fan-shaped circles.

[0049] Example 3 A method for fabricating a flexible ionized three-dimensional force sensor includes the following steps: The protruding force-bearing part of the dome structure is made of a flexible polymer doped with inorganic materials, and the base part is made of a flexible polymer; the first flexible substrate and the second flexible substrate are flexible polymer films; the first electrode and the second electrode are polymer films with micro-nano conductive materials on their surfaces; the three-dimensional force-sensitive layer is an elastomeric composite film doped with conductive fillers.

[0050] The inorganic material of the dome structure is selected from one or more of nano-silica and hexagonal boron nitride; the flexible polymer is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers. The protruding load-bearing part of the dome structure and the base part are prepared by molding. The protruding load-bearing part of the dome structure is frustum-shaped, with a top circular diameter of 2-3 mm, a bottom circular diameter of 3.5-4.5 mm, and a frustum height of 1.5-2 mm. The flexible polymer films of the first and second flexible substrates are selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers. The first flexible substrate and the dome structure are combined by dispensing.

[0051] The micro / nano conductive materials of the first and second electrodes are selected from one or more of carbon-based conductive materials and two-dimensional inorganic compounds with metallic conductivity; the carbon-based conductive materials are selected from one or more of single-layer graphene, multi-layer graphene, carbon black, single-walled carbon nanotubes, and multi-walled carbon nanotubes; the two-dimensional inorganic compound with metallic conductivity is MXene; the polymer films of the first and second electrodes are selected from polyethylene terephthalate (PET) films. The first and second electrodes are prepared by uniformly mixing the micro / nano conductive materials with a binder (SBR) and then spraying the mixture onto the surface of the polymer film. The first and second electrodes are divided into four equal parts by laser cutting or manual cutting, each part being a quarter circle with a radius of 2.25 mm and a spacing of 0.5 mm between each part. The thickness of both the first and second electrodes is 55–65 μm.

[0052] The conductive filler in the three-dimensional force-sensitive layer consists of an ionic liquid and conductive particles; the conductive particles are MXene; the ionic liquid is selected from one or more of poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, and 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide. The elastomer in the elastomer composite film is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers. The conductive filler and elastomer are mixed by solvent dispersion.

[0053] The three-dimensional force-sensitive layer is divided into four equal parts by laser cutting or manual cutting. Each part is a quarter circle with a radius of 2.25 mm and the interval between each part is 0.5 mm. The upper surface of the three-dimensional force-sensitive layer has a hierarchical unstable microstructure.

[0054] See Figure 8 The performance of the three-dimensional force sensor prepared according to the above scheme was tested. Since the robotic arm often experiences a certain normal force when sensing tangential force during intelligent assembly, to make this test more realistic for practical applications, the responses in both the X and Y directions were conducted under a normal force of 2 N. The corresponding normal force response, X-direction force response, and Y-direction force response are shown in Figure 7. Figure 10 and Figure 11 As shown.

[0055] See Figure 9 As can be seen from the positive pressure response data graph, the three-dimensional force sensor designed and prepared in this embodiment has a good capacitive response to positive pressure.

[0056] See Figure 10 and Figure 11As shown in the capacitance response data of the X and Y directions (hereinafter referred to as tangential force) when the normal pressure is 2 N, when the sensor is subjected to a 2 N normal pressure and a changing tangential force, the capacitance change of the two small sensor blocks pointing towards the tangential force increases with the increase of the tangential force, while the capacitance change of the two small sensor blocks pointing in the opposite direction of the tangential force decreases with the increase of the tangential force. Therefore, the flexible ionized three-dimensional force sensor designed and prepared in this embodiment has three-dimensional force sensing function and achieves high sensitivity: the maximum capacitance change under normal pressure is approximately 12.5 nF, the maximum capacitance change under tangential force is approximately 10 nF, and the range is wide: the sensing range for normal pressure is 0.2 N to 13.05 N, the sensing range for X tangential force is 0.02 N to 2.14 N, and the sensing range for Y tangential force is 0.0 N to 2.5 N.

[0057] Example 4 Please see Figure 1 This embodiment provides a flexible ionized three-dimensional force sensor, which includes a dome structure protruding force-bearing part, a dome structure base part, an upper flexible base, an upper electrode, an insulating spacer layer, a three-dimensional force-sensitive layer, a lower electrode, and a lower flexible base arranged sequentially.

[0058] In this embodiment, the dome structure is made by batch-coating a flexible polymer mixture doped with inorganic materials with a flexible polymer.

[0059] In this embodiment, the upper and lower electrodes can be formed from one or more combinations of gold, platinum, copper, silver, indium, conductive carbon, and MXene. The upper and lower electrodes can be bonded to the upper and lower flexible substrates respectively by hot pressing or dispensing.

[0060] In this embodiment, the three-dimensional force-sensitive layer 106 is selected from an elastomeric composite film doped with conductive fillers. The preparation method is as follows: the elastomer is thoroughly dispersed in a solvent under magnetic stirring at 80 °C. While maintaining the magnetic stirring temperature, conductive fillers are added to the well-dispersed solution and thoroughly mixed. The thoroughly mixed solution is transferred to a template with an anti-hierarchical unstable microstructure. Finally, solvent evaporation is performed at 80 °C to obtain the elastomeric composite film doped with conductive fillers.

[0061] Further, in a preferred embodiment, the ionic liquid is selected from one or more of poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, and 1-ethyl-3-methylimidazoline bis(trifluoromethylsulfonyl)imide.

[0062] Furthermore, in a preferred embodiment, the conductive particles are selected from MXene.

[0063] Furthermore, in a preferred embodiment, the elastomer in the elastomer composite film is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers.

[0064] Furthermore, in a preferred embodiment, the thickness of the three-dimensional force-sensitive layer 106 is 140–160 μm. Controlling the thickness of the three-dimensional force-sensitive layer 106 allows the product to have good flexibility and consistency, enabling it to bend and deform, and fit well into the robotic arm.

[0065] Furthermore, in a preferred embodiment, the upper and lower electrodes are obtained by spraying a uniformly mixed micro / nano conductive material with a binder (SBR) onto the surface of a polymer film. The polymer film is selected as polyethylene terephthalate (PET) film. The micro / nano conductive material is selected as MXene.

[0066] The flexible ionized three-dimensional force sensor provided in Example 4 can be used to realize precise grasping and intelligent assembly operations of robotic arms under multiple working conditions.

[0067] Example 5 Reference Figure 2 As shown, this embodiment proposes a flexible ionized three-dimensional force sensing array, including a dome structure array, a flexible substrate, an electrode array, an insulating spacer layer array 205, and a three-dimensional force-sensitive layer array 206. The flexible substrate includes a first flexible substrate portion 203 and a second flexible substrate portion 208. The electrode array includes a first electrode array 204 and a second electrode array 207. The dome structure array is provided with a protrusion array 201 and a dome substrate 202. One side of the protrusion array 201 is attached to one side of the dome substrate 202, and the other side of the dome substrate 202 is attached to one side of the first flexible substrate portion 203. The other side of the first flexible substrate portion 203 is attached to the first electrode array 207. One side of the first electrode array 204 is attached to the first electrode array 204, and the other side of the first electrode array 204 is attached to one side of the insulating spacer array 205. The other side of the insulating spacer array 205 is attached to one side of the three-dimensional force-sensitive layer array 206. One side of the three-dimensional force-sensitive layer array 206 has a hierarchical unstable microstructure. The other side of the three-dimensional force-sensitive layer array 206 is attached to one side of the second electrode array 207. The other side of the second electrode array 207 is attached to one side of the second flexible substrate portion 208. The three-dimensional force-sensitive layer array 206 is doped with a conductive filler, which is composed of ionic liquid and conductive particles. The surface of the electrode array is sprayed with a mixture of micro-nano conductive materials and binder.

[0068] The flexible ionized three-dimensional force sensing array provided in Example 5 can be used to realize precise grasping and intelligent assembly operations of robotic arms under multiple working conditions.

[0069] Example 6 A method for fabricating a flexible ionized three-dimensional force sensing array includes the following steps: On the dome array structure template, a flexible polymer mixture doped with inorganic materials and a flexible polymer are scraped in batches, and the dome array structure is obtained after heating and curing. A polymer film coated with micro / nano conductive materials is patterned into an upper electrode array using laser etching technology. The upper flexible substrate is then bonded to the upper electrode array via hot pressing or dispensing. The acquisition of the lower electrode array and its bonding to the lower flexible substrate are described in the same manner.

[0070] The elastomeric composite film and insulating spacer layer pattern with hierarchical unstable microstructure were cut into an array form using laser etching technology.

[0071] The upper flexible substrate, upper electrode array assembly, insulating spacer layer, and three-dimensional force-sensitive layer are aligned and assembled using dispensing to obtain an upper flexible substrate-upper electrode array-insulating spacer layer-three-dimensional force-sensitive layer assembly. This assembly is then aligned and assembled with the lower electrode array and lower flexible substrate assembly using hot pressing or dispensing to obtain an upper flexible substrate-upper electrode array-insulating spacer layer-three-dimensional force-sensitive layer array-lower electrode array-lower flexible substrate assembly. Finally, the dome array structure is combined with the upper flexible substrate using dispensing to obtain a flexible, electrically isolated three-dimensional force-sensing array.

[0072] Furthermore, in a preferred embodiment, the materials for each part are the same as those described in Embodiment 4 for the flexible ionized three-dimensional force sensor, resulting in a flexible ionized three-dimensional force sensing array.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A flexible, ionized three-dimensional force sensor, characterized in that, The device includes a dome structure, a flexible substrate, electrodes, an insulating spacer layer (105), and a three-dimensional force-sensitive layer (106). The flexible substrate includes a first flexible substrate (103) and a second flexible substrate (108). The electrodes include a first electrode (104) and a second electrode (107). The dome structure is provided with a protrusion (101) and a substrate (102). One end of the protrusion (101) is attached to one side of the substrate (102), and the other side of the substrate (102) is attached to one side of the first flexible substrate (103). The protrusion (101) is made of a flexible polymer material doped with inorganic materials, and the substrate (102) is made of a flexible polymer material. The inorganic material in the flexible polymer material doped with inorganic materials is selected from one or more of nano-silica and hexagonal boron nitride. The flexible polymer material is selected from one of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers. Or multiple types; the flexible substrate adopts a flexible polymer elastomer film, which is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers and polyolefin elastomers. The other side of the first flexible substrate (103) is attached to one side of the first electrode (104), the other side of the first electrode (104) is attached to one side of the insulating spacer layer (105), the other side of the insulating spacer layer (105) is attached to one side of the three-dimensional force-sensitive layer (106), and one side of the three-dimensional force-sensitive layer (106) has a hierarchical unstable microstructure. The hierarchical unstable microstructure includes protrusions (101) of multiple heights. The protrusions (101) are arranged in a gradient. The diameter of the head of the protrusion (101) is larger than the diameter of its root. The force-bearing part of the protrusion (101) is frustum-shaped, with a top circular diameter of 2~3mm, a bottom circular diameter of 3.5~4.5mm, and a frustum height of 1.5~2mm; The three-dimensional force-sensitive layer (106) is an elastomer composite film doped with conductive filler. The conductive filler and elastomer in the elastomer composite film doped with conductive filler are mixed by solvent dispersion. The conductive filler is composed of ionic liquid and conductive particles. The elastomer is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers and polyolefin elastomers. The conductive particles are MXene. The ionic liquid is selected from one or more of poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, and 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide. The other side of the three-dimensional force-sensitive layer (106) is attached to one side of the second electrode (107). The other side of the second electrode (107) is attached to one side of the second flexible substrate (108). The electrode is a polymer film with micro-nano conductive material on its surface. The electrode is prepared by spraying the micro-nano conductive material and the binder evenly onto the polymer film. On the surface of the molecular polymer film, the micro / nano conductive material is selected from one or more of carbon-based conductive materials and two-dimensional inorganic compounds with metallic conductivity. The polymer film is selected from polyethylene terephthalate film. The adhesive is styrene-butadiene rubber. The carbon-based conductive material is selected from one or more of single-layer graphene, multi-layer graphene, carbon black, single-walled carbon nanotubes, and multi-walled carbon nanotubes. The two-dimensional inorganic compound with metallic conductivity is MXene. The electrodes and the three-dimensional force-sensitive layer (106) are both equally divided into fan-shaped circles. The first electrode (104) and the second electrode (107) are divided into four equal parts, each of which is a quarter circle with a radius of 2.25 mm and a spacing of 0.5 mm between each part. The thickness of the first electrode (104) and the second electrode (107) is 55–65 μm. The three-dimensional force-sensitive layer (106) is divided into four equal parts, each of which is a quarter circle with a radius of 2.25 mm and a spacing of 0.5 mm between each part.

2. A method for fabricating a flexible ionized three-dimensional force sensor, wherein the flexible ionized three-dimensional force sensor described in claim 1 is fabricated, characterized in that, The process includes the following steps: attaching the dome structure, flexible substrate, electrode, insulating spacer (105) and three-dimensional force-sensitive layer (106) in the following order: protrusion (101), substrate (102), first flexible substrate (103), first electrode (104), insulating spacer (105), three-dimensional force-sensitive layer (106), second electrode (107) and second flexible substrate (108). The protrusion (101) is made of a flexible polymer material doped with inorganic materials; The substrate (102) is made of a flexible polymer material; The flexible substrate is made of a flexible polymer elastomer film; The electrode is made of a polymer film with micro-nano conductive material on its surface. The electrode is prepared by mixing the micro-nano conductive material with a binder and then spraying it onto the surface of the polymer film. The three-dimensional force-sensitive layer adopts an elastomer composite film doped with conductive filler. The conductive filler and elastomer in the elastomer composite film doped with conductive filler are mixed by solvent dispersion.

3. The method for fabricating a flexible ionized three-dimensional force sensor according to claim 2, characterized in that, The other side of the substrate (102) is bonded to one side of the first flexible substrate (103) by dispensing adhesive, and the other side of the first flexible substrate (103) is bonded to one side of the first electrode (104) and the other side of the second electrode (107) is bonded to one side of the second flexible substrate (108) by hot pressing or dispensing adhesive.

4. A flexible ionized three-dimensional force sensing array, characterized in that, The system includes a dome structure array, a flexible substrate, an electrode array, an insulating spacer layer array (205), and a three-dimensional force-sensitive layer array (206). The flexible substrate includes a first flexible substrate portion (203) and a second flexible substrate portion (208). The electrode array includes a first electrode array (204) and a second electrode array (207). The dome structure array is provided with a protrusion array (201) and a dome substrate (202). One side of the protrusion array (201) is attached to one side of the dome substrate (202), and the other side of the dome substrate (202) is attached to one side of the first flexible substrate portion (203). The protrusion array (201) is made of a flexible polymer material doped with inorganic materials, and the dome substrate (202) is made of a flexible polymer material. The inorganic material in the flexible polymer material doped with inorganic materials is selected from one or more of nano-silica and hexagonal boron nitride. The flexible polymer material is selected from thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and... One or more of polyolefin elastomers; the flexible substrate is a flexible polymer elastomer film, which is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers and polyolefin elastomers. The other side of the first flexible substrate portion (203) is attached to one side of the first electrode array (204), the other side of the first electrode array (204) is attached to one side of the insulating spacer array (205), the other side of the insulating spacer array (205) is attached to one side of the three-dimensional force-sensitive layer array (206), and one side of the three-dimensional force-sensitive layer array (206) has a hierarchical unstable microstructure. The hierarchical unstable microstructure includes protrusions (101) of multiple heights. The protrusions (101) are arranged in a gradient. The diameter of the head of the protrusion (101) is larger than the diameter of its root. The force-bearing part of the protrusion (101) is frustum-shaped, with a top circular diameter of 2~3 mm, a bottom circular diameter of 3.5~4.5 mm, and a frustum height of 1.5~2mm; The three-dimensional force-sensitive layer array (206) adopts an elastomer composite film doped with conductive filler, the conductive filler being composed of ionic liquid and conductive particles. The elastomer in the elastomer composite film doped with conductive filler is selected from one or more of thermoplastic polyurethane elastomers, polydimethylsiloxane elastomers, and polyolefin elastomers. The conductive particles are MXene. The ionic liquid is selected from one or more of poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, and 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imide. The other side of the three-dimensional force-sensitive layer array (206) is attached to one side of the second electrode array (207), and the other side of the second electrode array (207) is attached to one side of the second flexible substrate portion (208). The surface of the electrode array is sprayed with a mixture of micro-nano conductive material and adhesive, the adhesive being styrene-butadiene rubber. The micro-nano conductive material is selected from one or more of carbon-based conductive materials and two-dimensional inorganic compounds with metallic conductivity. The electrode array adopts a polymer film with micro-nano conductive material on its surface. The polymer film is selected from polyethylene terephthalate film; the carbon-based conductive material is selected from one or more of single-layer graphene, multi-layer graphene, carbon black, single-walled carbon nanotubes, and multi-walled carbon nanotubes; the two-dimensional inorganic compound with metallic conductivity is MXene; the first electrode array (204) includes a plurality of first electrodes (104), the second electrode array (207) includes a plurality of second electrodes (107), and the three-dimensional force-sensitive layer array (206) includes a plurality of three-dimensional force-sensitive layers (106); the first electrode The first electrode (104), the second electrode (107), and the three-dimensional force-sensitive layer (106) are all circularly divided into sector shapes; the first electrode (104) and the second electrode (107) are each divided into four parts, each a quarter circle with a radius of 2.25 mm and a spacing of 0.5 mm between each part. The thickness of both the first electrode (104) and the second electrode (107) is 55–65 μm; the three-dimensional force-sensitive layer (106) is also divided into four parts, each a quarter circle with a radius of 2.25 mm and a spacing of 0.5 mm between each part.

5. A method for fabricating a flexible ionized three-dimensional force sensing array, wherein the flexible ionized three-dimensional force sensing array of claim 4 is obtained, characterized in that, The process includes the following steps: sequentially attaching the dome structure array, flexible substrate, electrode array, insulating spacer array (205), and three-dimensional force-sensitive layer array (206) in the following order: protrusion array (201), dome substrate (202), first flexible substrate portion (203), first electrode array (204), insulating spacer array (205), three-dimensional force-sensitive layer array (206), second electrode array (207), and second flexible substrate portion (208); The dome structure array is made by batch-coating a flexible polymer mixture doped with inorganic materials and a flexible polymer in a dome structure array mold; The electrode array is prepared by uniformly mixing micro-nano conductive materials with binders and then spraying the mixture onto the surface of a polymer film. The polymer film pattern with micro-nano conductive materials on the surface is then cut to obtain the electrode array. The specific method for preparing the three-dimensional force-sensitive layer array is as follows: an elastomer composite film with a hierarchical unstable microstructure and doped conductive filler is prepared by solvent dispersion and molding, and then cut to obtain the three-dimensional force-sensitive layer array.

6. The method for fabricating a flexible ionized three-dimensional force sensing array according to claim 5, characterized in that, The other side of the dome base (202) is bonded to one side of the first flexible base portion (203) by dispensing adhesive, and the other side of the first flexible base portion (203) is bonded to one side of the first electrode array (204) and the other side of the second electrode array (207) is bonded to one side of the second flexible base portion (208) by hot pressing or dispensing adhesive.

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