Slip sensors based on uneven charge at contact interfaces and robotic hands and feet

Abstract

This invention discloses a slip sensor based on uneven charge at a contact interface, and a robot hand and foot. The sensor includes an electrode layer and a base layer, with the electrode layer disposed on the base layer. The electrode layer comprises four orthogonally symmetrically distributed electrodes: a front electrode, a rear electrode, a left electrode, and a right electrode. The electrode layer is used to contact the surface of a contact object. When relative sliding occurs with the surface of the contact object, each electrode generates a corresponding voltage signal. This invention can not only determine whether slippage has occurred, but also obtain specific information such as slippage distance, speed, and direction. It is manufactured using common manufacturing techniques while ensuring high slippage detection accuracy, enabling the robot to prevent slippage in a timely manner, or to make reasonable adjustments through output signals when slippage occurs.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and more specifically to a slip sensor based on uneven charge at the contact interface, and a robot hand and foot. Background Technology

[0002] Maintaining stability while grasping or manipulating objects is crucial for both humans and robots. Slippage is a common challenge because it disrupts the balance of forces and can even cause objects to fall. In humans, mechanoreceptors in the skin (SA-I, SA-II, RA-I, and RA-II) sense slippage and convert it into electrical signals that are transmitted to the brain. The brain then adjusts and regulates muscle strength and movement to ensure stable grasping and manipulation. Similarly, for intelligent robots such as surgical robots or intelligent prosthetics, slip sensing is essential for achieving stable and dexterous manipulation similar to that of a human hand.

[0003] Currently, there are two main methods for slip detection, each with its own limitations. The first method uses multi-axis force sensors to measure the normal and tangential forces at the contact interface. By comparing the ratio of the tangential to the normal force with the coefficient of friction, a slip event can be determined. However, this method requires prior knowledge of the coefficient of friction, which varies depending on the surface characteristics of the object being gripped; otherwise, slip detection may be unreliable. The second method relies on vibration detection, assuming that slip is accompanied by detectable vibrations. However, the frequency and amplitude of these vibrations are affected by various factors such as surface roughness and slip velocity. Setting empirical thresholds for determining slip events introduces uncertainty and may lead to inaccurate detection. In recent years, researchers have been exploring the use of artificial intelligence to analyze signals for slip detection. However, these methods rely on large amounts of labeled data, resulting in latency issues in real-time applications. Furthermore, due to the diversity of slip events, actual data may differ from labeled data, leading to lower detection accuracy. Additionally, these existing slip detection methods can only determine that slip has occurred, but cannot provide detailed information about the slip, such as distance, velocity, and angle. Summary of the Invention

[0004] The purpose of this invention is to provide a slip sensor based on uneven charge at the contact interface, which can not only determine whether slip has occurred, but also obtain specific information such as slip distance, speed, and direction; it can be manufactured using common manufacturing techniques while ensuring high slip detection accuracy, so that robots can prevent slip in time, or make reasonable adjustments in time through output signals when slip occurs.

[0005] The technical solution adopted in this invention is:

[0006] A sliding sensor based on uneven charge at a contact interface includes an electrode layer and a substrate layer, with the electrode layer disposed on the substrate layer. The electrode layer includes four orthogonally symmetrically distributed electrodes, namely a front electrode, a rear electrode, a left electrode, and a right electrode. The electrode layer is used to contact the surface of a contact object, and each electrode generates a corresponding voltage signal when relative sliding occurs with the surface of the contact object.

[0007] The four orthogonally symmetrically distributed electrodes refer to the following: the line connecting the front and rear electrodes is orthogonal to the line connecting the left and right electrodes; the front and rear electrodes are symmetrically arranged with respect to the line connecting the left and right electrodes; and the left and right electrodes are symmetrically arranged with respect to the line connecting the front and rear electrodes.

[0008] Preferably, the difference between the voltage signals generated by the front electrode and the rear electrode and the difference between the voltage signals generated by the left electrode and the right electrode are linearly related to the sliding distance along two orthogonal directions, respectively. By vector synthesis of these two sets of signal differences, the sliding distance and sliding direction are obtained, and the first derivative of the sliding distance is the sliding velocity.

[0009] Preferably, the sliding distance is: where k is a constant;

[0010] (1)

[0011] The sliding direction is: (2)

[0012] Among them, U X U FE and U BE The difference between them, U Y U RE and U LE The difference between them, during the slip process, is the potential of the front electrode relative to ground, U. FE The potential of the rear electrode relative to ground is U. BE The potential of the left electrode relative to ground is U. LE The potential of the right electrode relative to ground is U. RE .

[0013] Preferably, the electrode layer is made of a conductive material, and the base layer is made of an insulating material.

[0014] Preferably, the conductive material is any one of conductive metal materials, indium tin oxide, or flexible conductive composite materials.

[0015] Preferably, the insulating material is selected from aniline formaldehyde resin, polyoxymethylene, ethyl cellulose, polyamide nylon-11, polyamide nylon-66, wool and its fabrics, silk and its fabrics, paper, polyethylene glycol succinate, cellulose, cellulose acetate, polyethylene glycol adipate, diallyl phthalate, regenerated cellulose sponge, cotton and its fabrics, polyurethane elastomer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, wood, hard rubber, acetate, synthetic fibers, polymethyl methacrylate, polyvinyl alcohol, polyester, polyisobutylene, polyurethane elastic sponge, polyethylene terephthalate, polyvinyl butyral, butadiene-acrylonitrile copolymer, chloroprene rubber, natural rubber, polyacrylonitrile, poly(vinylidene chloride-CO acrylonitrile), polybisphenol A carbonate, polyvinyl chloride ether, polyvinylidene chloride, poly(2, Any one of the following: 6-dimethylpolyphenylene oxide, polystyrene, polyethylene, polypropylene, polydiphenylpropane carbonate, polyethylene terephthalate, polyimide, polyvinyl chloride, polydimethylsiloxane, polychlorotrifluoroethylene, polytetrafluoroethylene, and phenelzine.

[0016] Preferably, the shape of the electrode layer is any one of square, circular, rhomboid, square with a hole in the middle, circular with a hole in the middle, or rhomboid with a hole in the middle.

[0017] Preferably, the gap width between adjacent electrodes is less than or equal to 100 μm.

[0018] A robotic hand includes robotic fingers and a slip sensor, as described above, based on uneven charge at the contact interface, disposed on the tip of the robotic fingers. When the robot performs a grasping operation, the novel slip sensor detects whether the grasped object and the tip of the robotic fingers slide relative to each other. If a slip signal is detected, the grasping force is adjusted in time to prevent the slip from continuing.

[0019] A robot foot includes a slip sensor, as described above, based on uneven charge at the contact interface, disposed on the bottom of the robot foot. During robot walking, the novel slip sensor detects whether the robot foot slides relative to the ground during walking. If a slip signal is detected, the robot changes its path or adjusts its gait parameters in a timely manner.

[0020] The beneficial effects of this invention are:

[0021] This invention is based on the different electron-attracting abilities of material surfaces. The sliding process of a conductor on the surface of a dielectric is usually accompanied by the generation of interface charges. The generation of interface charges is non-uniform, with more charges generated at the leading edge of the conductor's movement. By using the different voltage signals generated by each electrode during the sliding process, it is possible not only to determine whether sliding has occurred, but also to obtain specific information such as sliding distance, speed, and direction. It is manufactured using common manufacturing techniques while ensuring high sliding detection accuracy, so that robots can prevent sliding in time, or make reasonable adjustments in time through output signals when sliding occurs. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the slip sensor based on uneven charge at the contact interface according to the present invention.

[0023] Figure 2a This is a schematic diagram illustrating the principle of voltage generation by the electrodes of the sliding sensor of the present invention.

[0024] Figure 2b This is a schematic diagram of the principle of the sliding sensor of the present invention.

[0025] Figure 3a This is a signal diagram of the sliding sensor of the present invention sliding different distances along the same direction.

[0026] Figure 3b The present invention calculates the sliding distance and the original signal from the sliding sensor sliding different distances along the same direction based on the original signal. A diagram illustrating the relationship between the two.

[0027] Figure 3c The present invention calculates the sliding distance and the original signal from the sliding sensor sliding different distances along the same direction based on the original signal. α A schematic diagram.

[0028] Figure 4a This is a signal diagram of the sliding sensor of the present invention sliding the same distance in different directions.

[0029] Figure 4b The present invention calculates the sliding direction and its relationship with the original signal obtained by the sliding sensor sliding the same distance in different directions. α A diagram illustrating the relationship between the two.

[0030] Figure 4c The present invention calculates the sliding direction and its relationship with the original signal obtained by the sliding sensor sliding the same distance in different directions. A diagram illustrating the relationship between the two.

[0031] Figure 5a This is a signal diagram of the sliding sensor of the present invention sliding the same distance in the same direction at different speeds.

[0032] Figure 5b The present invention calculates the sliding speed and its relationship based on the original signals from the sliding sensor sliding the same distance in the same direction at different speeds. The relationship diagram of the first-order partial derivatives.

[0033] In the diagram: 1-Base layer; 2-Electrode layer. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] In the description of this invention, it should be understood that if terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0036] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, and they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0037] A slip sensor based on uneven charge at a contact interface includes an electrode layer and a substrate layer, with the electrode layer disposed on the substrate layer. The electrode layer comprises four orthogonally symmetrically distributed electrodes: a front electrode, a rear electrode, a left electrode, and a right electrode. The electrode layer is used to contact the surface of a contacting object. When relative sliding occurs with the surface of the contacting object, each electrode generates a corresponding voltage signal. The voltage signals generated by each electrode can not only determine whether slippage has occurred but also obtain specific information such as slippage distance, speed, and direction. The substrate layer only serves a supporting function.

[0038] The electrodes and the contact object surface have different attraction to electrons. When relative sliding occurs, charge transfer occurs between the contact interfaces. The static charge accumulated on the contact object surface hinders the charge transfer between the contact interfaces, causing the front electrode in the direction of movement to accumulate more charge than the rear electrode, thus creating a potential difference between the two electrodes. The magnitude of the voltage is linearly related to the sliding distance.

[0039] The four orthogonally symmetrically distributed electrodes specifically refer to the following: the center line connecting the front and rear electrodes is orthogonal to the center line connecting the left and right electrodes; the front and rear electrodes are symmetrically arranged with respect to the center line connecting the left and right electrodes; and the left and right electrodes are symmetrically arranged with respect to the center line connecting the front and rear electrodes.

[0040] Furthermore, the voltage signals generated by the two sets of orthogonal symmetrical electrodes are linearly correlated with the slip distance along the two orthogonal directions, respectively. By vector synthesis of these two sets of signals, the slip direction can be obtained.

[0041] The rate of change of the voltage signal generated by the two sets of orthogonal symmetrical electrodes is related to the sliding speed. Therefore, the sliding speed can be obtained by detecting the rate of change of the voltage signal generated by the two sets of orthogonal symmetrical electrodes during the sliding process, that is, the first derivative of the voltage signal.

[0042] Furthermore, the difference between the voltage signals generated by the front electrode and the rear electrode and the difference between the voltage signals generated by the left electrode and the right electrode are linearly related to the sliding distance along two orthogonal directions, respectively. By vector synthesis of these two sets of signal differences, the sliding distance and sliding direction are obtained, and the first derivative of the sliding distance is the sliding velocity.

[0043] The sliding distance is: Where k is a correction coefficient, a constant (k typically takes values ​​of 0.8 ≤ k ≤ 1.2, but is not limited to this range and can be set in advance or determined experimentally based on specific environmental conditions), and the sliding distance is related to...

[0044] (1)

[0045] The sliding direction is: (2)

[0046] Among them, U X U FE and U BE The difference between them, U Y U RE and U LE The difference between them, during the slip process, is the potential of the front electrode relative to ground, U. FE The potential of the rear electrode relative to ground is U. BE The potential of the left electrode relative to ground is U. LE The potential of the right electrode relative to ground is U. RE .

[0047] Furthermore, the electrode layer is made of a conductive material, while the substrate layer is made of an insulating material.

[0048] Furthermore, the conductive material can be any one of conductive metal materials, indium tin oxide, or flexible conductive composite materials.

[0049] Furthermore, the conductive metal material is selected from any one of copper, aluminum, iron, zinc, nickel, chromium, titanium, tungsten, silver, gold, lead, and cobalt.

[0050] Furthermore, the insulating materials are selected from aniline-formaldehyde resin, polyoxymethylene, ethyl cellulose, polyamide nylon-11, polyamide nylon-66, wool and its fabrics, silk and its fabrics, paper, polyethylene glycol succinate, cellulose, cellulose acetate, polyethylene glycol adipate, diallyl phthalate, regenerated cellulose sponge, cotton and its fabrics, polyurethane elastomer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, wood, hard rubber, acetate, synthetic fibers, polymethyl methacrylate, polyvinyl alcohol, polyester, polyisobutylene, polyurethane elastic sponge, polyethylene terephthalate, polyvinyl butyral, butadiene-acrylonitrile copolymer, chloroprene rubber, natural rubber, polyacrylonitrile, poly(vinylidene chloride-CO acrylonitrile), polybisphenol A carbonate, polyvinyl chloride ether, polyvinylidene chloride, poly(2, Any one of the following: 6-dimethylpolyphenylene oxide, polystyrene, polyethylene, polypropylene, polydiphenylpropane carbonate, polyethylene terephthalate, polyimide, polyvinyl chloride, polydimethylsiloxane, polychlorotrifluoroethylene, polytetrafluoroethylene, and phenelzine.

[0051] Furthermore, the overall shape of the electrode layer can be varied according to requirements, such as square, circular, rhomboid, square, circular, rhomboid, and other symmetrical orthogonal shapes with holes in the middle.

[0052] When the electrode layer is square in shape, it is composed of four orthogonally symmetrically arranged square electrodes.

[0053] When the electrode layer is circular as a whole, the electrode layer is composed of four orthogonally symmetrical right-angled sectors spliced ​​together;

[0054] When the electrode layer is rhomboid in shape, it is composed of four orthogonally symmetrically arranged triangles.

[0055] Holes can also be drilled at the center of the above-mentioned square, round, and rhomboid electrode layers, as long as the four electrodes still satisfy orthogonal symmetry.

[0056] Furthermore, the gap width between adjacent electrodes is less than or equal to 100 μm.

[0057] Furthermore, the gap width between electrodes affects the sensing sensitivity and minimum detection limit of the sliding sensor. The gap width of the novel sliding sensor is controlled at 100 μm. At this gap width, the sensor has good sensitivity to sub-millimeter sliding and can detect a minimum sliding distance of 100 μm.

[0058] A robotic hand includes robotic fingers and a slip sensor, as described above, based on uneven charge at the contact interface, disposed on the fingertips. When the robot performs a grasping operation, the novel slip sensor detects whether the grasped object and the robot fingertips slide relative to each other. If a slip signal is detected, the grasping force is adjusted in time to prevent the slip from continuing, thereby ensuring the stability of the robot during operation.

[0059] A robot foot includes a slip sensor, as described above, based on uneven charge at the contact interface, disposed on the bottom of the robot foot. During robot walking, the novel slip sensor detects whether the robot foot slides relative to the ground. If a slip signal is detected, the robot changes its path or adjusts its gait parameters in a timely manner to achieve stable movement.

[0060] When relative sliding occurs at the contact interface, the difference in the amount of charge accumulated on the symmetrical electrodes causes a potential difference between the two electrode tips. The longer the sliding distance, the greater the voltage; the faster the sliding speed, the faster the voltage change rate. Based on the corresponding relationship, the distance, direction, and speed of the sliding can be calculated and fed back to the robot control system to ensure that the robot makes reasonable motion adjustments. In summary, the sliding sensor based on uneven charge at the contact interface provided by this invention, compared with existing technologies, can directly convert sliding events into electrical signals, improving the accuracy of sliding detection. It can detect sliding as small as sub-millimeter level. More importantly, it can acquire specific sliding information such as sliding distance, speed, and direction, which is a function not available in previous sliding sensors. The sensor has a simple structure, does not require complex manufacturing processes, and can easily achieve large-scale rapid mass production. The overall structure of the sensor is compact and can be easily integrated into various parts of the robot body, such as the robot's fingertips or soles, thereby ensuring the stability of the robot during operation or movement. This invention can achieve mass production quickly through a simple process, while also ensuring high measurement accuracy. It has broad application prospects in robot adaptive grasping, dexterous operation, and human-computer interaction.

[0061] The working principle of this invention: This invention provides a slip sensor that converts slip information into electrical signals to detect whether slip has occurred and to acquire information such as slip distance, direction, and speed. Slip sensors installed on the fingertips or soles of a robot can detect slip events during grasping or movement, thereby adjusting the gripping force or gait in a timely manner to ensure stable grasping or movement. The slip sensor of this invention utilizes the phenomenon of non-uniform charge generation at the interface between a conductor and a dielectric during the slip process to convert slip events into electrical signals.

[0062] For ease of explanation, the principles of the present invention will be described below with reference to the typical structure shown in Figure 1. However, it is obvious that these contents are not limited to the embodiments shown in Figure 1, but can be used for all technical solutions disclosed in the present invention.

[0063] Figure 1 This invention presents a typical structure for a slip sensor, comprising: an electrode layer 1 and a substrate layer 2. When the sensor slides relative to the dielectric surface, the four orthogonally symmetrical electrodes generate electrical signals. These signals differ due to variations in the slip distance and direction. By comparing these differences, not only can slippage be detected, but also the slip distance, direction, and velocity can be determined.

[0064] The working principle of the sliding sensor of the present invention is as follows: Figure 2aAs shown, the slippage process between a conductor and a dielectric is usually accompanied by the generation of interface charges. The generation of these interface charges is non-uniform, with more charges generated at the leading edge of the conductor's movement. This leads to charge flow within the conductor during the slippage process. This charge transfer is highly sensitive to slippage; the amount, speed, and direction of charge transfer are closely related to the slippage distance, speed, and direction.

[0065] like Figure 2b As shown, the slip sensor consists of four symmetrical triangular electrodes: the front electrode, the rear electrode, the left electrode, and the right electrode (FE, BE, LE, and RE). We measure the ground potential of the four electrodes during the slip process, denoted as U0. FE U BE U RE and U LE U FE and U BE The difference between them is represented by U X U RE and U LE The difference U between Y Indicated. Since the front and rear electrodes are symmetrical along the Y direction, therefore U X It depends only on the slip distance along the X direction. Similarly, U Y It depends only on the slip distance along the Y direction. (U) X and U Y Treating them as vectors along the X and Y directions respectively, a composite vector containing the slip distance can be obtained. and sliding direction α Information vector . The slip direction α can be calculated using the following formula:

[0066] (1)

[0067] (2)

[0068] Figure 3a The image shows the original signal from a sliding sensor that has slid different distances along the same direction. Figure 3b and Figure 3c According to Figure 3a The original signal was calculated And α. We can see It is proportional to the slip distance, and α is a constant value.

[0069] Figure 4a This is a raw signal graph of a sliding sensor sliding the same distance in different directions. Figure 4b and Figure 4c According to Figure 4a The original signal was calculated And α. It can be seen that α and the slip direction are basically the same. It is a constant value.

[0070] Figure 5a This is a raw signal image of a sliding sensor sliding the same distance along the same direction at different sliding speeds. Figure 5b for Figure 5a The original signal was calculated The first-order partial derivative. We can see... The first-order partial derivative is proportional to the slip velocity.

[0071] Example 1: This example uses the slip sensor structure shown in Figure 1. The electrode layer is rhomboid in shape, and the electrodes are triangular. The base layer 1 is made of polyimide (PI) film, and the electrode layer 2 is made of copper foil. The electrode gap width is 0.1 mm, and the entire electrode layer is a square with a side length of 15 mm. The slip sensor is installed on the inside of the gripper of a two-finger robotic gripper. During the gripping process, the robotic gripper can detect whether there is relative slippage between the object and the gripper fingertips. The slip signal can be used for feedback control, that is, after detecting a slip event, the gripping force is increased in time until the slip signal disappears. With the slip information provided by the slip sensor, the robotic gripper can complete the gripping without requiring a large gripping force, which ensures the stability of the grip and prevents the object from slipping or even falling off, while also avoiding damage to the gripped object due to excessive gripping force.

[0072] Example 2: This example uses the slip sensor structure shown in Figure 1. The substrate layer 1 is made of polydimethylsiloxane (PDMS) film, and the electrode layer 2 is made of conductive composite material. The electrode pattern is obtained by screen printing the conductive composite material onto the PDMS substrate. The electrode gap width is 0.1 mm, and the entire electrode layer is a square with a side length of 10 mm. The slip sensor is installed on the fingertips of a five-fingered bionic hand. If the bionic hand collides with an external obstacle while grasping an object, the grasped object and the bionic fingertips will slide relative to each other. By detecting the slip information from multiple fingertips, including slip distance, direction, and speed, the location of the collision and the change in the relative position between the grasped object and the hand after the collision can be further determined, thus providing guidance for subsequent rescue measures.

[0073] Example 3: This example uses the slip sensor structure shown in Figure 1. The base layer 1 is made of polyimide (PI) film, the electrode layer 2 is made of copper foil, the electrode gap width is 0.1 mm, and the electrode layer as a whole is a square with a side length of 10 mm. The slip sensor is installed on the sole of the hexapod robot's foot, and the relative sliding between the sole and the toe tip during the hexapod robot's movement can be detected in a timely manner. During the movement of the hexapod robot, slippage may occur due to changes in the path conditions, such as when going uphill. After detecting the slippage event, the robot can avoid slippage by replanning the path or adjusting its gait, thereby ensuring stability during walking.

[0074] The slip sensor for robotic electronic skin of this invention has a simple structure, requires no complex manufacturing process, and is easily integrated into various parts of the robot's body, such as the robot's fingertips or soles. The slip sensor of this invention can be well integrated with other types of sensors, achieving multimodal sensing integration without affecting the functionality of other sensors. The slip information detected by the slip sensor can be used as feedback control information during robot operation, adjusting the gripping force or walking gait in a timely manner during robot grasping or walking to prevent continuous slippage, thereby ensuring stability during operation or movement.

[0075] In summary, this invention discloses a slip sensor based on uneven charge at the contact interface, belonging to the field of slip detection technology. The novel slip sensor mainly comprises symmetrical electrodes and a substrate. Its principle is based on the different electron-attracting abilities of material surfaces. The slip process of a conductor on a dielectric surface is usually accompanied by the generation of contact interface charges, which are uneven, with more charges generated at the conductor's moving front. The electrode structure of the novel slip sensor consists of four orthogonally symmetrical electrodes. When relative sliding occurs with the dielectric, the charge difference accumulated on the symmetrical electrodes leads to a potential difference between the two electrodes. The magnitude of the voltage is related to the slip distance. By vector synthesis of two sets of voltage signals extracted from the two sets of orthogonally stacked electrodes, it is possible not only to determine whether slip has occurred but also to obtain information such as slip distance, speed, and direction. This novel slip sensor has a simple structure and can achieve sub-millimeter-level high-sensitivity slip sensing without complex manufacturing processes. The novel slip sensor can be very compactly integrated into the fingertips or soles of a robot, where slip may occur. When slip occurs at the contact surface, it can make judgments based on the signals and take timely corresponding controls to prevent slippage.

[0076] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0077] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A slip sensor based on uneven charge at a contact interface, characterized in that: It includes an electrode layer and a base layer, with the electrode layer disposed on the base layer; wherein, the electrode layer includes four orthogonally symmetrically distributed electrodes, namely the front electrode, the rear electrode, the left electrode, and the right electrode, the electrode layer is used to contact the surface of the contacting object, and each electrode generates a corresponding voltage signal when relative sliding occurs with the surface of the contacting object; Four orthogonally symmetrically distributed electrodes refer to the following: the line connecting the front electrode and the rear electrode is orthogonal to the line connecting the left electrode and the right electrode; the front electrode and the rear electrode are symmetrically arranged with respect to the line connecting the left electrode and the right electrode; and the left electrode and the right electrode are symmetrically arranged with respect to the line connecting the front electrode and the rear electrode. The difference between the voltage signals generated by the front and rear electrodes and the difference between the voltage signals generated by the left and right electrodes are linearly related to the sliding distance along two orthogonal directions, respectively. By vector synthesis of these two sets of signal differences, the sliding distance and sliding direction are obtained. The first derivative of the sliding distance is the sliding velocity. The gap width between adjacent electrodes is less than or equal to 100 μm.

2. The slip sensor based on uneven charge at the contact interface as described in claim 1, characterized in that: The sliding distance is: where k is a constant; （1） The sliding direction is: (2) Among them, U X U FE and U BE The difference between them, U Y U RE and U LE The difference between them, during the slip process, is the potential of the front electrode relative to ground, U. FE The potential of the rear electrode relative to ground is U. BE The potential of the left electrode relative to ground is U. LE The potential of the right electrode relative to ground is U. RE .

3. The slip sensor based on uneven charge at the contact interface as described in claim 1, characterized in that: The electrode layer is made of a conductive material, while the base layer is made of an insulating material.

4. The slip sensor based on uneven charge at the contact interface as described in claim 3, characterized in that: The conductive material can be any one of conductive metal materials, indium tin oxide, or flexible conductive composite materials.

5. The slip sensor based on uneven charge at the contact interface as described in claim 3, characterized in that: The insulating material is selected from any one of aniline formaldehyde resin, polyoxymethylene, polyamide nylon-11, polyamide nylon-66, wool and its fabrics, silk and its fabrics, cellulose, polyurethane elastic sponge, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, wood, hard rubber, acetate, polyvinyl alcohol, polyester, polymethyl methacrylate, polyisobutylene, polyvinyl butyral, butadiene-acrylonitrile copolymer, chloroprene rubber, natural rubber, polyacrylonitrile, poly(vinylidene chloride-CO acrylonitrile), polyvinyl chloride ether, polyvinylidene chloride, poly(2,6-dimethylphenylene oxide), polystyrene, polyethylene, polypropylene, polyimide, polyvinyl chloride, polydimethylsiloxane, polychlorotrifluoroethylene, polytetrafluoroethylene, and pyrene. The polyester is selected from any one of polyethylene glycol adipate, diallyl phthalate, bisphenol A carbonate, diphenylpropane carbonate, polyethylene terephthalate, and polyethylene glycol succinate.

6. The slip sensor based on uneven charge at the contact interface as described in claim 1, characterized in that: The shape of the electrode layer can be any one of square, circular, or rhomboid.

7. The slip sensor based on uneven charge at the contact interface as described in claim 1, characterized in that: The electrode layer can be any one of the following shapes: square with a central hole, circular with a central hole, or rhomboid with a central hole.

8. A robotic hand, characterized in that: It includes a robot finger and a slip sensor based on uneven charge at the contact interface as described in any one of claims 1 to 7, which is disposed on the tip of the robot finger. When the robot performs a grasping operation, the slip sensor detects whether the grasped object and the robot fingertip slide relative to each other. If a slip signal is detected, the grasping force is adjusted in time to prevent the slip from continuing to occur.

9. A robotic leg, characterized in that: Includes a slip sensor based on uneven charge at the contact interface as described in any one of claims 1 to 7, which is installed on the sole of the robot's foot; during the robot's walking process, the slip sensor detects whether the robot's foot slides relative to the ground during walking, and if a slip signal is detected, the robot changes its path or adjusts its gait parameters in a timely manner.

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