Electronic skin force sensing system and gripping device

Abstract

This application discloses an electronic skin force sensing system and gripping device, relating to the fields of electronic skin and force sensing technology. The system includes an insulating substrate, metal electrodes, a dielectric layer, multiple detection electrodes, and a processing module. The multiple detection electrodes include tangential force detection units and normal force detection units. At least a portion of the projected area of ​​the tangential force detection unit is located within the movable range of the metal electrodes. The projected area of ​​the normal force detection unit is located outside the movable range of the metal electrodes and is completely covered by them. The processing module is configured to: acquire the initial capacitance value of the normal force detection unit when the electronic skin is not under force, and the corresponding normal force capacitance value after force is applied; calculate the normal force based on the initial capacitance value and the normal force capacitance value; and acquire the comprehensive capacitance value of the tangential force detection unit after force is applied to the electronic skin, and calculate the tangential force based on the comprehensive capacitance value and the normal force capacitance value.

Description

Technical Field

[0001] This application relates to the field of electronic skin and force sensing technology, and more specifically, to an electronic skin force sensing system and a gripping device. Background Technology

[0002] Electronic skin (E-skin), a key component endowing robots, prosthetics, and smart wearable devices with tactile sensing capabilities, primarily functions to simulate the human skin's perception of external mechanical signals such as pressure and friction. Currently, capacitive electronic skin is widely used due to its advantages such as simple structure, high sensitivity, and low power consumption. Traditional capacitive electronic skin typically consists of upper and lower electrodes and an intermediate dielectric layer. When subjected to external force, the electrode spacing or the area of ​​the electrodes changes, thereby causing a change in capacitance.

[0003] However, existing mainstream capacitive electronic skin structures generally have a significant limitation: they can only effectively sense normal forces, but cannot sense tangential forces parallel to the skin surface. This is because the sensing mechanism relies on the change in the spacing between parallel plate electrodes under external force to modulate the capacitance value. Therefore, such structures inherently lack the ability to sense tangential mechanical behaviors such as sliding and shearing.

[0004] In practical applications, electronic skin often experiences both normal forces (pressure perpendicular to the skin surface) and tangential forces (shear or frictional forces parallel to the skin surface). For example, in the grasping operations of flexible robots, when a robotic hand contacts a smooth or fragile object (such as glassware or fruit), normal force information alone is insufficient to determine whether the object is about to slip. Only by monitoring the changes in tangential force at the contact interface in real time and accurately can the slippage trend be identified promptly and the grasping strategy dynamically adjusted, thereby achieving safe and reliable adaptive grasping. Similarly, in intelligent prostheses, sports rehabilitation monitoring, and human-computer interaction systems, tangential force information is crucial for understanding complex contact states and interpreting precise operational intentions.

[0005] In summary, the current lack of multi-dimensional force sensing capabilities in capacitive electronic skin, especially the inadequacy of tangential force detection, has become a key bottleneck restricting its widespread application in high-level intelligent systems. Summary of the Invention

[0006] The main objective of this application is to provide an electronic skin force sensing system and gripping device to solve the problem of the lack of tangential force detection in capacitive electronic skin in related technologies.

[0007] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of this application.

[0008] According to a first aspect of this application, a capacitive electronic skin is provided, comprising: Insulating substrate; Metal electrode plates are laid on the insulating substrate; A dielectric layer is applied over the metal electrode plate; Multiple detection plates are arranged above the dielectric layer, and each detection plate and the metal plate form a capacitor through the dielectric layer; at least some of the multiple detection plates are configured as tangential force detection units. The metal electrode is configured to be displaced relative to the plurality of detection electrodes when subjected to tangential or tilting forces; at least a portion of the projected area of ​​the tangential force detection unit is located within the movable range of the metal electrode, such that the movement of the metal electrode can change the facing area between them.

[0009] In an exemplary embodiment of this application, at least a portion of the plurality of detection plates are configured as normal force detection units; the projected area of ​​the normal force detection unit is located outside the movable range of the metal detection plate and is completely covered by the metal detection plate, and the movement of the metal detection plate does not cause a change in the area directly opposite to it.

[0010] In one exemplary embodiment of this application, the tangential force detection unit includes two tangential force detection plates, which are symmetrically arranged along a certain direction; When not subjected to external force, the metal electrode plate and the two tangential force detection electrodes each have partially overlapping and partially non-overlapping areas in the direction perpendicular to the insulating substrate.

[0011] In one exemplary embodiment of this application, the tangential force detection unit includes four tangential force detection plates, which are respectively located on the upper side, lower side, left side, and right side of the normal force detection unit.

[0012] In one exemplary embodiment of this application, the plurality of detection plates further includes an additional detection unit, the additional detection unit including at least one additional detection plate, the at least one additional detection plate being arranged between two adjacent tangential force detection plates.

[0013] In one exemplary embodiment of this application, four additional detection plates are provided, and the four additional detection plates correspond one-to-one with the four quadrant regions and are located at four diagonal positions.

[0014] In one exemplary embodiment of this application, the shape of the plurality of detection plates is selected from at least one of circles, rectangles, ellipses, triangles, and irregular shapes.

[0015] In one exemplary embodiment of this application, an isolation well is further included, which is formed on the surface of the dielectric layer and located in a non-connection region between adjacent detection electrodes.

[0016] According to a second aspect of this application, a gripping device is provided, comprising a gripping device and any of the above-described capacitive electronic skin, wherein the capacitive electronic skin is disposed on the side of the gripping device that contacts the target object to be gripped.

[0017] In one exemplary embodiment of this application, the grasping device is configured as any one of a robot, a robotic arm, or a wearable device.

[0018] The exemplary embodiments of this application may have some or all of the following beneficial effects: The electronic skin force sensing system provided in the example embodiment of this application, through the relative arrangement of the metal electrode plate and the detection electrode plate and the signal processing logic, achieves decoupled detection of normal force and tangential force while maintaining a flat structure and high flexibility, effectively overcoming the defect of lack of tangential force sensing in the prior art. Specifically, this system divides multiple detection electrode plates into tangential force detection units and normal force detection units. The projected area of ​​the normal force detection unit is set outside the movable range of the metal electrode plate and is always completely covered, ensuring that when the metal electrode plate is subjected to tangential force or tilting force and undergoes horizontal displacement, the facing area of ​​the normal force detection unit remains constant, and its capacitance change is only caused by the compressive deformation of the dielectric layer (i.e., normal force), thereby obtaining a normal force reference signal that is not disturbed by tangential movement. At the same time, part of the tangential force detection unit is located within the movable range of the metal electrode plate, and its capacitance change comprehensively reflects the dual effects of the change in facing area (tangential force dominant) and the change in dielectric layer thickness (normal force dominant). The processing module uses the initial capacitance value corresponding to the normal force detection unit and the normal force capacitance value after force is applied to calculate the magnitude of the normal force on the electronic skin. Similarly, the processing module uses the comprehensive capacitance value detected by the upper tangential force detection unit and the normal force capacitance value to calculate the capacitance value corresponding to the tangential force, and thus the magnitude of the tangential force on the electronic skin. Therefore, through this structure, the electronic skin can detect both the magnitude of the normal force and the magnitude of the tangential force, effectively improving the multi-dimensional force sensing capability of the capacitive electronic skin.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application and to make other features, objects, and advantages of the application more apparent. The illustrative embodiments and descriptions of this application are used to explain the application and do not constitute an undue limitation of the application. In the drawings: Figure 1 This illustration shows a structural schematic diagram of an electronic skin force sensing system equipped with two tangential force detection plates according to an embodiment of this application; Figure 2 A partial layer structure diagram of the electronic skin in an embodiment of this application is shown; Figure 3 This illustration shows a structural schematic diagram of an electronic skin force sensing system equipped with four tangential force detection plates according to an embodiment of this application; Figure 4 The diagram shows a structural schematic of an electronic skin force sensing system in an embodiment of the application, which is equipped with four tangential force detection plates and two additional detection plates. Figure 5 The diagram shows a structural schematic of an electronic skin force sensing system according to an embodiment of this application, which is equipped with four tangential force detection plates and four additional detection plates.

[0021] Among them, 1. Insulating substrate; 2. Metal electrode plate; 3. Detection electrode plate; 31. Normal force detection unit; 311. Normal force detection electrode plate; 32. Tangential force detection unit; 321. Tangential force detection electrode plate; 33. Additional detection unit; 331. Additional detection electrode plate; 4. Dielectric layer; 5. Isolation well. Detailed Implementation

[0022] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore their detailed descriptions will be omitted. Furthermore, the drawings are merely illustrative of this application and are not necessarily drawn to scale.

[0023] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples in the accompanying drawings. It is understood that if the device of the icon is flipped so that it is upside down, the component described as "upper" will become the component described as "lower." When a structure is "upper" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0024] The terms “a,” “one,” “the,” and “at least one” are used to indicate the existence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first” and “second” are used only as markers and are not a limitation on the number of objects.

[0025] Furthermore, the terms "set up," "equipped with," "connected," and "fixed" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] In addition, the term "multiple" should mean two or more.

[0027] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] In this application embodiment, an electronic skin force sensing system is provided. This system is mainly applied to the fingertips of flexible robots, the surface of intelligent prosthetics, or human-computer interaction touch panels to sense the normal pressure and tangential shear force of the contact interface in real time.

[0029] The electronic skin force sensing system includes an insulating substrate 1, a metal electrode 2, a dielectric layer 4, multiple detection electrodes 3, and a processing module.

[0030] The insulating substrate 1 is made of flexible polymer materials such as polyimide, polyethylene terephthalate, or silicone, possessing good mechanical flexibility and electrical insulation properties, and can be adhered to curved surfaces, such as robotic arm joints or human skin. The metal electrode 2 is laid on the insulating substrate 1 by methods such as printing, vapor deposition, or laser etching.

[0031] The metal electrode 2 can be made of flexible conductive materials such as copper, silver, gold, or conductive polymers. Its shape can be designed as rectangular, circular, triangular, or other irregular structures as needed, without any restrictions. When the metal electrode 2 is subjected to tangential or inclined forces, it can be displaced on the surface of the insulating substrate 1, but it will not detach from the substrate.

[0032] A dielectric layer 4 covers the metal electrode 2. Serving as the dielectric of the capacitor, the dielectric layer 4 is composed of a flexible polymer material with a high dielectric constant, such as polydimethylsiloxane, Ecoflex, or silicone rubber. The thickness and / or relative dielectric constant of this dielectric layer 4 can change under external force. The dielectric layer 4 serves both as the dielectric material of the capacitor and as support for the upper detection electrode 3.

[0033] Multiple detection plates 3 are arranged on the side of the dielectric layer 4 away from the metal plate 2 (i.e., the upper surface of the dielectric layer 4). The multiple detection plates 3 are insulated from the metal plate 2, and each detection plate 3 forms a parallel-plate capacitor with the metal plate 2 through the intermediate dielectric layer 4. The multiple detection plates 3 are fabricated on a flexible circuit board using photolithography, screen printing, or laser direct writing processes, or directly deposited on the surface of the dielectric layer 4. The multiple detection plates 3 are spatially divided into at least two functional units: a tangential force detection unit and a normal force detection unit 31.

[0034] The maximum horizontal displacement range that the metal electrode 2 can undergo when subjected to the maximum expected tangential force is called the "movable range". This range is usually centered on the initial static position of the metal electrode 2 and extends outwards by a certain distance.

[0035] Regarding the normal force detection unit 31, its projected area is set outside the movable range of the metal electrode 2, and the normal force detection unit 31 is always completely covered by the metal electrode 2 when the metal electrode 2 undergoes any expected horizontal displacement. In other words, no matter how the metal electrode 2 slides within its movable range, the area between the metal electrode 2 and the normal force detection unit 31 remains unchanged (equal to the area of ​​the normal force detection unit 31 itself). When the electronic skin is subjected to a tangential force, the capacitance value of the normal force detection unit 31 theoretically does not change; however, when subjected to a normal force or tilting force, the dielectric layer 4 is compressed, the distance between the metal electrode 2 and the normal force detection unit 31 decreases, resulting in an increase in capacitance. Therefore, the capacitance signal output by the normal force detection unit 31 only reflects the effect of the normal force and is not affected by tangential displacement, thus allowing the magnitude of the normal force to be determined.

[0036] Regarding the tangential force detection unit, at least a portion of its projected area lies within the movable range of the metal electrode 2. Preferably, a portion of the tangential force detection unit is located within the coverage area of ​​the initial position of the metal electrode 2, while another portion extends to the edge or outside of the movable range. When the metal electrode 2 is subjected to a tangential force and undergoes horizontal displacement, the facing area between the metal electrode 2 and the tangential force detection unit changes. According to the formula for a parallel-plate capacitor, the change in the facing area directly leads to a change in the capacitance value of the unit. Therefore, the capacitance signal output by the tangential force detection unit is a comprehensive reflection of both tangential displacement (causing a change in the facing area) and normal pressure (causing a change in the electrode spacing), referred to as the "comprehensive capacitance value."

[0037] The processing module is electrically connected to both the tangential force detection unit and the normal force detection unit 31. The processing module can be a microcontroller integrated on a flexible circuit board, an integrated circuit, or a data acquisition card that communicates with a host computer. The processing module internally stores a preset calibration algorithm or lookup table and is configured to perform the following steps: First, the normal force is calculated. The processing module obtains the initial capacitance value of the normal force detection unit 31 when the electronic skin is in a stress-free state (zero load state). When the electronic skin is subjected to force, the normal force capacitance value of the normal force detection unit 31 is read in real time. Since the facing area of ​​the normal force detection unit 31 remains unchanged, the change in capacitance is caused by the change in the thickness of the dielectric layer 4. The processing module can calculate the current normal force using the initial capacitance value and the normal force capacitance value.

[0038] Next, the tangential force is calculated. The processing module reads the comprehensive capacitance value of the tangential force detection unit when the electronic skin is subjected to force. As mentioned earlier, the comprehensive capacitance value is affected by both the normal force (changing the spacing) and the tangential force (changing the area). If the comprehensive capacitance value is used directly to calculate the tangential force, a huge error in the normal force will be introduced. Therefore, the processing module uses the real-time normal force capacitance value obtained in the previous steps for calculation. Specifically, the processing module subtracts the normal force capacitance value from the comprehensive capacitance value; the difference reflects the capacitance change caused by the tangential force, and thus the tangential force is calculated.

[0039] Through the above processing method, this embodiment separates the coupled mechanical signals, achieving high-precision multi-dimensional force sensing.

[0040] In practical use, when the surface of the electronic skin is subjected to force: if the force includes a normal force, the dielectric layer 4 is compressed, and the metal electrode 2 moves towards multiple detection electrodes 3. At this time, the capacitance values ​​of both the normal force detection unit 31 and the tangential force detection unit increase due to the decrease in spacing. When a finger simultaneously applies a horizontal pushing force, the metal electrode 2 slides horizontally relative to the detection electrodes 3. Since the normal force detection unit 31 is always completely covered by the metal electrode 2, its facing area remains unchanged, so its capacitance value is determined only by the amount of compression of the dielectric layer 4; while the tangential force detection unit, due to the sliding out or in of the metal electrode 2, has a smaller or larger facing area, causing its capacitance value to change further on top of the pressure-induced change. The processing module acquires two signals in real time. First, it calculates the normal force from the data of the normal force detection unit 31, and then uses the data combining the normal force capacitance value detected by the normal force detection unit 31 and the comprehensive capacitance value detected by the tangential force detection unit to finally output the normal force and tangential force.

[0041] Specifically, the normal force detection unit 31 can be positioned at the center of the entire sensing area, although this is not a limitation. Its shape can be circular, rectangular, elliptical, triangular, or other irregular shapes, and its size is smaller than the overall area of ​​the metal electrode 2. Since the metal electrode 2 mainly undergoes translation or slight rotation when subjected to tangential or tilting forces, and the normal force detection unit 31 is completely covered by the metal electrode 2, even if the metal electrode 2 shifts, the overlapping area of ​​its projection with the normal force detection unit 31 in the vertical direction remains unchanged. Thus, the change in capacitance of the capacitor mainly reflects the magnitude of the pressure in the vertical direction (i.e., the normal direction), and is unaffected by the tangential component.

[0042] In this embodiment, the processing module is further configured to: calculate the distance between the metal electrode 2 and the multiple detection electrodes 3 after the force is applied based on the normal force capacitance value; and calculate the normal force based on the distance and the first facing area between the normal force detection unit 31 and the metal electrode 2.

[0043] By integrating the tangential force detection unit 32 and the normal force detection unit 31 into the same device, this electronic skin can synchronously and independently acquire tangential and normal force information, achieving multi-dimensional tactile perception. For example, when a robot grasps an object, the normal force signal can be used to determine the degree of grip, while the tangential force signal can be used to detect whether the object is slipping, thereby improving the safety and intelligence of the operation.

[0044] Furthermore, the processing module is further configured to: calculate the tangential force capacitance value corresponding to the tangential force acting on the electronic skin based on the comprehensive capacitance value and the normal force capacitance value; Based on the tangential force capacitance value and the distance between the metal plate 2 and the multiple detection plates 3 after being subjected to force, the second facing area between the metal plate 2 and the tangential force detection unit 32 after being subjected to force and moving is calculated. Based on the initial and second facing areas of the metal electrode 2 and the tangential force detection unit 32 when the metal electrode 2 is not under force, the change in the facing area of ​​the metal electrode 2 and the tangential force detection unit 32 is calculated. The tangential force is calculated based on the change in the area of ​​the metal electrode 2 and the tangential force detection unit 32.

[0045] Specifically, in this embodiment, all detection plates 3 are squares of the same size. Of course, in other embodiments, the multiple detection plates 3 can be set to other shapes (e.g., triangles, circles, rectangles, or irregular shapes). The magnitude of the normal force can be calculated by the capacitance change of the normal force detection unit 31. This capacitance value... Determined by the following formula: , in, The normal force capacitance value of the normal force detection unit 31 after being subjected to a force, in farads (F). In engineering, the pelvis method is commonly used. , ), Nafa ( , ); Vacuum permittivity (standard physical constant); The relative permittivity of a medium (dimensionless, such as air). , Human tissue ); The area of ​​the normal force detection unit 31 facing the metal electrode 2, in square millimeters. ); The distance between the normal force detection unit 31 and the metal electrode plate 2 after being subjected to force (i.e., the thickness of the dielectric layer 4), in millimeters. ).

[0046] During the normal force detection process, when external pressure is applied perpendicularly or obliquely to the surface of the electronic skin, the dielectric layer 4 undergoes elastic deformation under pressure, resulting in the spacing... Decrease, thereby causing capacitance Increased. Because the metal electrode 2 always completely covers the normal force detection unit 31 even when it is displaced by tangential or tilting forces, the area directly opposite the metal electrode 2 and the normal force detection unit 31 is increased. It remains unchanged. Therefore, the change in capacitance is determined solely by the spacing. The change is caused by [the change] and is unrelated to tangential motion.

[0047] The spacing is derived by detecting the change in capacitance of the normal force detection unit 31 in real time and combining it with the capacitance formula mentioned above. The magnitude of the applied normal force can be quantitatively determined by combining the changed numerical value with the initial distance between the metal electrode 2 and the normal force detection unit 31. Specifically, the normal force can be determined by the following formula: , , in, This is the initial capacitance value of the original normal force detection unit 31. The normal force acting on the electronic skin. The relative permittivity of intermediate dielectric layer 4 is given by [insert value here]. It represents the Young's modulus of intermediate medium layer 4.

[0048] This mechanism enables independent measurement of normal pressure, providing a reliable basis for multidimensional tactile perception.

[0049] Furthermore, the magnitude of the tangential force can be calculated through the capacitance change of the tangential force detection unit 32. If the force on the tangential force detection unit 32 is a tangential force parallel to the electronic skin, then the tangential force detection unit 32 reads only the result caused by the tangential force. If the force on the tangential force detection unit 32 is an inclined force, the metal electrode 2 undergoes in-plane displacement on the surface of the insulating substrate 1, resulting in an increase in the area of ​​the metal electrode 2 facing the tangential force detection unit 32. Changes occur, and simultaneously, due to the presence of tilting pressure, medium layer 4 is compressed, and the spacing... It will also decrease. To accurately extract the area change information caused by tangential displacement, this invention adopts the following decoupling strategy: The tilting force on the electronic skin is decomposed into normal force and tangential force. The change in capacitance value of tangential force detection unit 32 includes the changes caused by both normal force and tangential force. That is, the force is determined by normal force detection unit 31. If the capacitance value of normal force detection unit 31 does not change, it means that the force on the electronic skin is only tangential force. If the capacitance values ​​of both normal force detection unit 31 and tangential force detection unit 32 change, it means that the force on the electronic skin is a mixture of normal force and tangential force, i.e., tilting force.

[0050] The data obtained by the normal force calculation unit 31 is then processed by the capacitor of the tangential force detection unit 32 to remove the influence of the normal force on the capacitance difference, thus obtaining the capacitance difference caused solely by the tangential force.

[0051] , in, The capacitance value of the tangential force detection unit 32 after being subjected to force is expressed in farads (F). In engineering, the pelvis method is commonly used. , ), Nafa ( , ); The capacitance value remaining after removing the normal force capacitance value from the tangential force detection unit 32 is the tangential force capacitance value corresponding to the tangential force. Furthermore, , in, The area of ​​the tangential force detection unit 32 facing the metal electrode plate 2, in square millimeters. ).

[0052] This The initial facing area when there is no external force By comparison, the area change of the tangential force detection unit 32 can be obtained. Then through The magnitude of the tangential force can be obtained from this, where K is the stiffness coefficient of the medium layer 4.

[0053] Reference Figure 1 As shown, in one specific embodiment of this application, the normal force detection unit 31 includes a normal force detection electrode 311. The metal electrode 2 always completely covers the normal force detection electrode 311 in the initial state and during the displacement caused by the force, thereby ensuring that the facing area between the two remains constant and is not affected by tangential or tilt displacement.

[0054] The tangential force detection unit 32 includes two tangential force detection plates 321, namely a first tangential force detection plate and a second tangential force detection plate, which are symmetrically arranged along a certain straight line (e.g., a straight line along the X-axis). When no external force is applied, the metal plate 2 has a partially overlapping area with both the first and second tangential force detection plates in the direction perpendicular to the insulating substrate 1, and there is also a partially non-overlapping area.

[0055] When the electronic skin is subjected to a tangential force applied along the Y-axis, the metal electrode 2 is displaced, causing a differential change in its overlap state with the two tangential force detection electrodes 321, as detailed below: If the tangential force direction is toward the second tangential force detection electrode (e.g., along the -Y axis direction), the overlap area between the metal electrode 2 and the second tangential force detection electrode increases, while the overlap area with the first tangential force detection electrode decreases. If the tangential force direction is toward the first tangential force detection electrode (e.g., along the +Y axis direction), the overlap area between the metal electrode 2 and the first tangential force detection electrode increases, while the overlap area with the second tangential force detection electrode decreases.

[0056] Furthermore, when the electronic skin is subjected to a tangential force perpendicular to the aforementioned direction (e.g., along the X-axis), the metal electrode 2 moves as a whole along the X-direction, causing it to simultaneously move away from or towards the edges of the two tangential force detection electrodes 321. This results in the overlapping area with the first and second tangential force detection electrodes decreasing or increasing synchronously, as detailed below: If the tangential force is along the +X axis, the overlap area between the metal electrode 2 and the two tangential force detection electrodes 321 increases; If the tangential force is along the −X-axis, the overlap area between the metal electrode 2 and the two tangential force detection electrodes 321 is reduced.

[0057] By monitoring the changes in capacitance values ​​of the capacitors corresponding to the first and second tangential force detection plates in real time and analyzing the changes in the overlapping area, the direction of the tangential force can be determined. Thus, based on the detection of the magnitude of the tangential force, the direction of the tangential force in a two-dimensional plane is further identified, effectively improving the spatial perception capability of the electronic skin.

[0058] Reference Figure 3 and Figure 4 As shown, in another specific embodiment of this application, the tangential force detection unit 32 of the capacitive electronic skin includes four tangential force detection plates 321, and the normal force detection unit 31 includes one normal force detection plate 311. The four tangential force detection plates 321 are respectively arranged on the upper side, lower side, left side and right side of the normal force detection plate 311, forming a cross-shaped layout around the central normal force detection plate 311.

[0059] Specifically, the normal force detection unit 31 is located at the center of the sensing area and is circular, rectangular, elliptical, triangular, or irregularly shaped, without restriction, and is used to detect pressure in the vertical direction; four tangential force detection plates 321 are symmetrically distributed around it: one is located at the top (denoted as the upper plate), one at the bottom (lower plate), one on the left (left plate), and one on the right (right plate). All detection plates 3 are disposed on the upper surface of the dielectric layer 4, electrically isolated from each other, and each forms an independent capacitor with the metal plate 2 below it through the dielectric layer 4.

[0060] In the initial state without external force, the metal plate 2 completely covers the normal force detection plate 311. The metal plate 2 and the four tangential force detection plates 321 can either completely or partially cover each other in the vertical direction.

[0061] When the electronic skin is subjected to a tangential or tilting force in any direction within the plane, the metal electrode 2 undergoes displacement in the corresponding direction, resulting in a characteristic change in the area of ​​the metal electrode 2 facing the four tangential force detection electrodes 321. For example: If the tangential force is along the +X direction (to the right), the overlapping area of ​​the left electrode plate decreases, while the overlapping area of ​​the upper and lower electrodes plate remains unchanged. If the tangential force is along the +Y direction (upward), the overlapping area of ​​the lower plate decreases, while the overlapping area of ​​the left and right plates remains unchanged. If the tangential force is along the diagonal direction (such as the upper right), the overlapping area of ​​the left and lower plates will decrease simultaneously.

[0062] By synchronously acquiring the capacitance signals corresponding to the four tangential force detection plates 321 and combining them with a differential algorithm, the vector direction and magnitude of the tangential force in the two-dimensional plane can be accurately calculated. Meanwhile, since the normal force detection unit 31 is always completely covered by the metal plate 2, its capacitance change only reflects the thickness change of the dielectric layer 4 and is not affected by tangential displacement, thus achieving complete decoupling measurement of normal and tangential forces.

[0063] Reference Figure 4 and Figure 5 As shown, in this embodiment, the multiple detection plates 3 further include an additional detection unit 33. The additional detection unit 33 includes at least one additional detection plate 331, which is arranged between any two tangential force detection plates 321. That is, the four tangential force detection plates 321 can divide the electronic skin into four quadrant regions, and the at least one additional detection plate 331 can be located in the upper left quadrant, upper right quadrant, lower right quadrant, and lower left quadrant. The additional detection plates 331 can be used to enhance spatial resolution, detect torsional torque, or provide redundant sensing signals, further improving the electronic skin's ability to perceive complex contact states.

[0064] Reference Figure 4 As shown, in one specific embodiment, two additional detection electrodes 331 are configured, respectively arranged in the lower right quadrant and lower left quadrant of the area enclosed by the upper, lower, left, and right tangential force detection electrodes 321. These two additional detection electrodes 331, together with the four tangential force detection electrodes 321, surround the outer periphery of the normal force detection electrode 311, forming an equilateral triangle structure. This arrangement enhances the sensitivity of the electronic skin to tangential forces or tilted contacts in the lower region.

[0065] Reference Figure 5As shown, in another specific embodiment, four additional detection plates 331 are configured, and these four additional detection plates 331 are respectively disposed in the upper left, upper right, lower right, and lower left quadrant regions, that is, located at the upper left corner between the upper and left tangential force detection plates 321, the upper right corner between the upper and right sides, the lower right corner between the lower and right sides, and the lower left corner between the lower and left sides. This arrangement can improve the electronic skin's ability to detect tangential forces or torques in the diagonal direction.

[0066] Reference Figure 2 , Figure 4 and Figure 5 As shown in the embodiment of this application, the capacitive electronic skin also includes an isolation well 5. The isolation well 5 is formed on the surface of the dielectric layer 4 and is disposed in the non-connection area between any two adjacent detection plates 3, that is, in the gap where each detection plate 3 is not connected to each other.

[0067] Specifically, multiple detection electrodes 3 (including a normal force detection electrode 311, a tangential force detection electrode 321, and an additional detection electrode 331) are arranged in an array on the upper surface of the dielectric layer 4, with micrometer-level gaps between adjacent electrodes to achieve electrical isolation. Within the dielectric layer 4 below these gaps, recessed trenches or cavities are formed using microfabrication processes (such as laser etching, reactive ion etching, etc.), forming the isolation wells 5. The depth of the isolation wells 5 can penetrate part or all of the thickness of the dielectric layer 4, and the width matches the gap between adjacent detection electrodes 3, with a typical size of 5–50 micrometers.

[0068] The isolation well 5 can be an air-filled cavity or a low-dielectric-constant material (such as fluorinated polymers, porous silica, etc.), whose dielectric constant is significantly lower than that of the main material of the dielectric layer 4. By introducing this low-dielectric or air isolation structure between adjacent detection plates 3, the parasitic capacitance between the plate edges is effectively reduced, signal crosstalk is suppressed, and the independence of each capacitor unit is improved.

[0069] In this application embodiment, a gripping device is also provided, including a gripping device and any of the above-described electronic skin force sensing systems. The electronic skin is attached to or integrated into the surface of the gripping device that contacts the target object being gripped, such as the fingertip, the inner wall of the gripper, or the palm area, for real-time sensing of mechanical information during the contact process.

[0070] Specifically, when the gripping device performs a gripping action, the electronic skin simultaneously detects normal and tangential forces. The capacitance signal output by the normal force detection unit 31 reflects the magnitude of the gripping force, while the tangential force detection unit 32 identifies whether the object is sliding and its direction of sliding through changes in differential capacitance. For example, when the object being gripped begins to slide downwards on the fingertips, the area of ​​the lower tangential force detection plate 321 facing the metal plate 2 increases, while the area of ​​the upper plate facing each other decreases. Based on this, the system determines the sliding trend and triggers a grip strength enhancement command.

[0071] In this embodiment, the gripping device can be any one of a robot, a robotic arm, or a wearable device.

[0072] Other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the embodiments thereof. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not claimed in this application. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the appended claims.

Claims

1. An electronic skin force sensing system, characterized in that, It includes an insulating substrate, metal electrodes, a dielectric layer, multiple detection electrodes, and a processing module; The metal electrode plate is laid on the insulating substrate; The dielectric layer covers the metal electrode plate; The plurality of detection plates are arranged on the side of the dielectric layer away from the metal plate, and each detection plate and the metal plate form a capacitor through the dielectric layer; the plurality of detection plates include a tangential force detection unit and a normal force detection unit; The metal electrode is configured to be displaced relative to the plurality of detection electrodes when subjected to tangential or tilting forces; at least a portion of the projected area of ​​the tangential force detection unit is located within the movable range of the metal electrode, so that the movement of the metal electrode changes the facing area between them; the projected area of ​​the normal force detection unit is located outside the movable range of the metal detection electrode and is completely covered by the metal detection electrode, and the movement of the metal detection electrode does not cause a change in the facing area between them; The processing module, electrically connected to both the tangential force detection unit and the normal force detection unit, is configured as follows: The system acquires the initial capacitance value of the normal force detection unit when the electronic skin is unloaded and the normal force capacitance value after being loaded with force; and calculates the normal force based on the initial capacitance value and the normal force capacitance value. The comprehensive capacitance value of the tangential force detection unit after being subjected to force is obtained when the electronic skin is subjected to force, and the tangential force is calculated based on the comprehensive capacitance value and the normal force capacitance value.

2. The electronic skin force sensing system according to claim 1, characterized in that, The processing module is further configured to: Based on the normal force capacitance value, the distance between the metal electrode plate and the plurality of detection electrodes after the force is applied is calculated; The normal force is calculated based on the spacing and the first facing area between the normal force detection unit and the metal electrode plate.

3. The electronic skin force sensing system according to claim 2, characterized in that, The processing module is further configured to: Based on the comprehensive capacitance value and the normal force capacitance value, the tangential force capacitance value corresponding to the tangential force experienced by the electronic skin is calculated; Based on the tangential force capacitance value and the spacing, calculate the second directly opposite area between the metal electrode plate and the tangential force detection unit after the metal plate moves under force; Based on the initial facing area of ​​the metal electrode plate and the tangential force detection unit when the metal electrode plate is not under force and the second facing area, the change in the facing area of ​​the metal electrode plate and the tangential force detection unit is calculated. The tangential force is calculated based on the change in the area of ​​the metal electrode plate facing the tangential force detection unit.

4. The electronic skin force sensing system according to claim 2, characterized in that, The processing module is further configured to calculate the distance between the metal electrode plate and the plurality of detection electrodes after the metal electrode plate is subjected to force, according to the following method: ， in, The normal force capacitance value, vacuum permittivity, The relative permittivity of the dielectric layer, The area of ​​the normal force detection unit facing the metal electrode plate. The distance between the metal electrode plate and the plurality of detection electrodes after the metal electrode plate is subjected to force.

5. The electronic skin force sensing system according to claim 4, characterized in that, The normal force detection unit is set to a square, and the processing module is further configured to calculate the normal force according to the following method: ， ， in, The initial capacitance value, The change in capacitance value of the normal force detection unit after being subjected to force is the amount of change. The Young's modulus of the dielectric layer. It is the normal force.

6. The electronic skin force sensing system according to claim 3, characterized in that, The processing module is further configured to calculate the change in the area of ​​the metal electrode plate facing the tangential force detection unit in the following manner: ， ， ， in, This refers to the comprehensive capacitance value; The tangential force capacitance value. The normal force capacitance value, The area directly opposite the tangential force detection unit after the metal electrode plate is moved under force; This refers to the initial area directly opposite the metal electrode plate and the tangential force detection unit when the metal electrode plate is not under stress.

7. The electronic skin force sensing system according to claim 1, characterized in that, The tangential force detection unit includes four tangential force detection plates, which are located on the upper, lower, left, and right sides of the normal force detection unit, respectively.

8. The electronic skin force sensing system according to claim 7, characterized in that, The plurality of detection plates also include an additional detection unit, the additional detection unit including at least one additional detection plate, the at least one additional detection plate being arranged between two adjacent tangential force detection plates.

9. A gripping device, characterized in that, It includes a gripping device and an electronic skin force sensing system as described in any one of claims 1-8.

10. The gripping device according to claim 9, characterized in that, The grasping device can be any one of a robot, a robotic arm, or a wearable device.

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