Multi-mode flexible touch finger for intelligent operation of electric power inspection robot

Abstract

The invention discloses a multi-mode flexible touch finger for intelligent operation of an electric power inspection robot, which comprises a base, the top of the base is provided with a top proximity sense sensing module and a top pressure sensing module, and the base is internally provided with a front side pressure sensing module and an internal tangential force sensing module; the top pressure sensing module is a single-row pressure sensing array and comprises n resistive flexible pressure sensors; the top proximity sense sensing module is a single-row proximity sense sensing array and is laid on the upper surface of the top pressure sensing module; the front side pressure sensing module is an m * n pressure sensing array and comprises m * n resistive flexible pressure sensors; the internal tangential force sensing module comprises four resistance-type flexible pressure sensors forming a full-bridge structure, and the four resistance-type flexible pressure sensors are distributed in the peripheral side direction of the front side pressure sensing module. The flexible touch finger has the advantages that the flexible touch finger with multi-mode sensing capabilities such as proximity sense sensing capability, high-resolution array pressure sensing capability and tangential force sensing capability is provided for a robot.

Description

Technical Field

[0001] This invention relates to the field of sensors, specifically to a multimodal flexible tactile finger for intelligent operation of power inspection robots. Background Technology

[0002] Power line inspection robots, due to their advantages such as high inspection efficiency, low labor costs, and strong adaptability, are gradually becoming an important component of the intelligent and digital development of power systems. Currently, power line inspection robots mainly acquire positioning signals and perform status monitoring through vision, including using a first-view camera mounted on the end effector of the robotic arm and a fixed third-view camera installed in the working environment for monitoring the operation process. However, when faced with common working environments in power line inspections, such as multiple obstacles, confined spaces, and complex lighting conditions, visual signals inevitably suffer from poor stability, low accuracy, and blind spots, making it difficult to meet the requirements of high-precision, high-safety, and high-stability inspection operations.

[0003] In recent years, researchers have made many efforts in the field of improving the high-precision operation capabilities and operational safety of robots: The academic paper "Nonlinearity synergy: An elegant strategy for realizing high-sensitivity and wide-linear-range pressure sensing" (Pang Yaokun, Xu Xianchen, Chen Shoue, et al. Nonlinearity synergy: An elegant strategy for realizing high-sensitivity and wide-linear-range pressure sensing[J]. Nature Communications, 2023, 14(1): 6641.) utilizes a pyramid-shaped carbon foam array as the sensing layer and an elastomer gasket as the stiffness regulator to develop a sensor with a sensitivity of 24.6 kPa. -1 A flexible pressure sensor with high sensitivity and a wide linear sensing range of 1.4MPa was integrated into the gripping surface of a robot gripper to prepare a closed-loop control system based on pressure sensing signal feedback. This system can grip steel blocks and tofu, monitor the gripping status, and prevent slippage and damage to the tofu, showing great application potential in the fields of intelligent robot operation and human-computer interaction.

[0004] The academic paper "Flexible Tactile End Effector for Intelligent Gripping and Twisting Operations of Power Inspection Robots" (Guo Xinxin, Teng Fei, Guo Xu, et al. Flexible Tactile End Effector for Intelligent Gripping and Twisting Operations of Power Inspection Robots [J]. Micro-Nano Electronics Technology, 2024, 61(10): 100403.) proposes a highly sensitive flexible capacitive pressure sensor with a microstructured composite ion gel dielectric layer. This capacitive pressure sensor exhibits high sensitivity (26.85 kPa) at relatively low pressures (0~75 kPa). -1 and high linearity (correlation coefficient R) 2 =0.994), and it also exhibits a certain sensitivity (12.58 kPa) under higher pressures (75~270 kPa). -1 and higher linearity (R) 2 =0.997). Combining a differential structure with the developed flexible pressure sensor, a flexible tactile end effector for robots with clamping and twisting sensing functions was developed. It was applied to two types of twisting operations: single-mode ST pigtails and rotary switches. It can effectively distinguish three common states during twisting: relative sliding, normal twisting, and jamming, thereby improving the safety of power inspection robot operations.

[0005] The academic paper "Flexible Tactile End Effector for Insertion and Removal Operations of Inspection Robots" (Huang Houzhu, Teng Fei, Yu Hongbo, et al. Flexible Tactile End Effector for Insertion and Removal Operations of Inspection Robots [J]. Electronic Components and Materials, 2024, 43(9): 1207-1213.) prepared a capacitive flexible pressure sensing unit based on a composite porous ion gel dielectric layer, which has high sensitivity (17.2 kPa). -1 It features a wide detection range (0~500kPa). Furthermore, a Hall-type tangential force sensing unit was designed by combining a Hall chip, an elastomer, and a neodymium iron boron magnet, exhibiting high sensitivity (8.610 mT·N). -1 It features a wide detection range (0~20N). Integrating pressure and tangential force sensing units, a flexible tactile end effector for robots with multi-dimensional force sensing capabilities was fabricated. This end effector was applied to the insertion and removal of plugs and fiber optic pigtails. With the assistance of this end effector, the inspection robot can monitor and determine typical working states such as slippage, normal operation, and jamming during insertion and removal operations in real time, effectively improving the success rate of the inspection robot. However, while the proposed flexible tactile end effector possesses pressure and tangential force sensing capabilities, it lacks proximity sensing capabilities and the ability to monitor end-effector distances in confined spaces. Furthermore, capacitive pressure sensors are difficult to array at high density, and the end effector lacks the ability to monitor high-resolution pressure distribution signals at the contact surface. The proposed Hall effect tangential force sensing unit based on magnetic field changes is susceptible to interference from environmental magnetic fields, affecting the signal reliability of the flexible tactile end effector in complex application scenarios.

[0006] Patent application CN119974028A discloses an adaptive center of gravity adjustment method and system for a handling robot. It uses sensors to collect three-dimensional information of the object, contact force distribution information, and contact force information between the robot and the object. Utilizing deep learning algorithms, visual feature vectors are extracted from the three-dimensional image information, and tactile feature vectors are extracted from the contact force distribution and contact force information. The extracted visual and tactile feature vectors are then fused to obtain a multimodal feature set. By utilizing real-time feedback information, the control algorithm and control strategy are optimized, thus proposing an adaptive center of gravity adjustment method.

[0007] Patent application CN119115933A discloses a robotic arm obstacle avoidance method based on an EIT tactile sensor. This method acquires tactile information using the EIT tactile sensor, reconstructs tactile sensing images, detects target objects and boxes using a vision module, and obtains the target position and placement position through coordinate transformation. During the robotic arm's movement, changes in the conductivity of the EIT tactile sensor's sensing area monitor the contact between the obstacle and the robotic arm, calculates the collision change center, and feeds back the contact point position to the control module to replan the route until the target object's placement position is reached. This robotic arm obstacle avoidance method based on an EIT tactile sensor can actively perceive and build obstacle models, planning a safer and more reliable robotic arm movement path.

[0008] Patent application CN119915415A discloses a dual-modal tactile sensor, a fruit-picking system, and a picking robot. A piezoresistive sensor and a triboelectric sensor were fabricated. By integrating the dual-modal tactile sensor, a fruit-picking system and robot with tactile sensing capabilities were developed. This effectively solves the problem of insufficient reliability of dynamic information and grasping force obtained due to the inability to detect dynamic information characterizing fruit ripeness and the applied grasping force at the same grasping point.

[0009] Patent application CN119458332A discloses a high-precision object pose estimation and fine manipulation method based on visual-tactile fusion. It acquires visual and tactile information through physical interaction between the robot and its environment, thereby achieving accurate pose estimation in dynamic scenes. A hand-based object pose correction algorithm based on particle filtering is constructed, significantly improving the robot's ability to cope with dynamic interactive environments. High-precision manipulation tasks are performed on objects with different geometric shapes, demonstrating that the method achieves accurate pose estimation with a translation error of 1-2 mm and a rotation error of approximately 2 degrees, while also handling dynamic situations such as object sliding. This enhances the robot's high-precision operational capabilities.

[0010] Although some progress has been made in recent years in improving the high-precision operation capabilities and safety of power inspection robots, the following shortcomings still exist: 1. Currently, in the power inspection operation environment, visual signals are usually used for autonomous navigation and positioning. However, visual signals are difficult to work stably in narrow spaces blocked by obstacles such as complex wiring and in complex lighting conditions, resulting in poor environmental adaptability and operational safety.

[0011] 2. In power line inspection operations beyond line of sight, robotic grippers need a stable and reliable small-scale proximity sensing system. Existing lidar and visual imaging technologies cannot simultaneously meet the requirements of miniaturization and high-precision distance sensing over a small area. How to design a miniaturized and high-precision proximity sensor over a small area is an urgent problem to be solved in the intelligent operation of inspection robots.

[0012] 3. In power line inspection operations involving button pressing, the robotic gripper tip needs a pressure sensing system to determine the button's self-locking and limit states, significantly improving safety during the pressing process and reducing button damage rates during robotic inspections. Currently, commercial robotic grippers lack miniaturized pressure sensing systems, limiting safety in robot inspection pressing scenarios.

[0013] 4. In power line inspection scenarios, there are common requirements for gripping various objects. Relying solely on a single pressure signal is insufficient to monitor the posture information of the object being gripped. If the safe movement path of the gripped object conflicts with the movement path of the inspection operation, the gripped object will be damaged. Currently, commercial robotic grippers typically lack a high-density pressure sensing array on their inner side, making it impossible to monitor the posture information of the object being gripped.

[0014] 5. In power inspection operations, there are many plug-in / plug-out tasks. When relying solely on pressure sensors to monitor the plug-in / plug-out status during intelligent inspection operations, the lack of tangential force monitoring and slippage status monitoring capabilities results in significant gaps in process information during plug-in / plug-out scenarios in robot inspection operations, leading to low safety.

[0015] 6. Power line inspection operations need to balance precision micro-operations and heavy-duty tasks, requiring pressure sensors to possess both high sensitivity and a wide pressure sensing range. However, existing flexible pressure sensors suffer from polarization: sensors used for human physiological monitoring have narrow ranges, while sensors used for heavy industrial loads have low sensitivity. There is a lack of flexible pressure sensors that combine high sensitivity and a wide pressure sensing range, making it difficult to meet the needs of robot gripping force and pressure monitoring. Summary of the Invention

[0016] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multimodal flexible tactile finger for intelligent operation of power inspection robots. This aims to improve the problems of poor pressure perception, lack of anti-collision capability, lack of proximity and multi-dimensional force perception capabilities of robot tactile fingers. The invention enables the power inspection robot operation system based on the robot tactile finger to monitor the end-effector pose status in real time, monitor the end-effector gripping force, pressing force and sliding status, and has collision detection and collision warning capabilities, significantly improving the system's operation success rate and safety.

[0017] This invention is achieved through the following technical solution: This invention first discloses a multimodal flexible tactile finger for intelligent operation of power inspection robots, including a base. The top of the base is provided with a top proximity sensing module and a top pressure sensing module, and the inside of the base is provided with a front pressure sensing module and an internal tangential force sensing module.

[0018] The top pressure sensing module is a single-row pressure sensing array, including n resistive flexible pressure sensors, which are embedded in the top groove of the base. The top of the top pressure sensing module is encapsulated by a top pressure contact encapsulation layer, which is exposed from the top groove.

[0019] The top proximity sensing module is a single-row proximity sensing array, comprising n capacitive proximity sensors, laid on the top pressure contact encapsulation layer.

[0020] The front pressure sensing module is an m×n pressure sensing array, including m×n resistive flexible pressure sensors, which are installed in the cavity inside the base. The front side of the front pressure sensing module is encapsulated by a side pressure contact encapsulation layer, which is exposed from the front side of the base; where m represents the number of rows and n represents the number of columns.

[0021] The internal tangential force sensing module is installed in the internal cavity of the base and includes four resistive flexible pressure sensors that form a full-bridge electrical bridge structure, distributed on the periphery of the front pressure sensing module.

[0022] Furthermore, the resistive flexible pressure sensor comprises an electrode layer, a high-conductivity layer, a low-conductivity layer, and an encapsulation layer stacked sequentially. The electrode layer consists of two spaced rectangular electrode segments and a flexible elastic material segment located between the two rectangular electrode segments; the low-conductivity layer has a conductivity not exceeding 10 S·cm. -1 The stretchable length is not less than 50%; the electrical conductivity of the high-conductivity layer is not less than 1000 S·cm. -1The stretchable length is no more than 5%; the encapsulation layer consists of two spaced low-hardness encapsulation segments and a high-hardness encapsulation segment located between the two low-hardness encapsulation segments. The Shore hardness of the low-hardness encapsulation segment is no greater than 30A, and the Shore hardness of the high-hardness encapsulation segment is no less than 70A, and the high-hardness encapsulation segment can be completely covered by the flexible elastic material segment. The electrode layer thickness of the resistive flexible pressure sensor is 100~500μm, the low-conductivity layer thickness is 20~200μm, the high-conductivity layer thickness is 10~200μm, and the encapsulation layer thickness is 300μm~1mm.

[0023] Furthermore, the front pressure sensing module is located on the front side of the main flexible circuit board. The upper and lower ends of the main flexible circuit board are respectively provided with a set of horizontally extending forward sets of horizontal mounting structures. Each set of horizontal mounting structures includes two horizontal flaps arranged on the left and right. The four resistive flexible pressure sensors of the internal tangential force sensing module are correspondingly set inside the four horizontal flaps. The main flexible circuit board is wrapped with an elastic gasket with a front opening. The four horizontal flaps of the main flexible circuit board are exposed from the clearance grooves opened on the upper and lower sides of the elastic gasket. The area enclosed by the four resistive flexible pressure sensors of the tangential force sensing module is also provided with a main rigid connecting frame. The main rigid connecting frame is provided with a number of grid holes arranged in an array. The m×n resistive flexible pressure sensors of the front pressure sensing module are correspondingly set in the number of grid holes of the main rigid connecting frame.

[0024] Furthermore, the top pressure sensing module is disposed on the upper surface of the top flexible circuit board, which is disposed on two horizontal flaps at the upper end of the main flexible circuit board.

[0025] Furthermore, the front pressure sensing module has an m×n side pressure contact array on the rear side of the side pressure contact encapsulation layer, including m×n pressure contacts. The m×n side pressure contacts on the rear side of the side pressure contact encapsulation layer are embedded one-to-one into several grid holes of the main rigid connection frame.

[0026] Furthermore, a top rigid connecting frame is embedded in the top groove of the base. The top rigid connecting frame has several grid holes arranged in an array, and the n resistive flexible pressure sensors of the top pressure sensing module are correspondingly arranged in the several grid holes of the top rigid connecting frame. Even further, the bottom of the top pressure contact encapsulation layer of the top pressure sensing module has a single-row top pressure contact array, including n top pressure contacts, and the n top pressure contacts at the bottom of the top pressure contact encapsulation layer are correspondingly embedded in the several grid holes of the top rigid connecting frame.

[0027] Furthermore, the multimodal flexible tactile finger incorporates a built-in signal acquisition circuit, which consists of two parts: a front-end sensing electrode and signal transmission circuit, and a mid-range signal processing circuit. The mid-range signal processing circuit utilizes an internal signal acquisition circuit board, which is embedded in the lower cavity inside the base and sealed by a lower cover plate. This mid-range signal processing circuit integrates a resistance-to-voltage conversion circuit, a row and column scanning control circuit, an analog-to-digital conversion circuit, and a capacitance acquisition chip, used to convert the analog signals from each sensing module into digital signals and transmit them to an external host computer. The front-end sensing electrode and signal transmission circuit are made of a flexible circuit board, enabling electrical connection between each sensing module and the mid-range signal processing circuit.

[0028] Furthermore, the specific arrangement of the front-end sensing electrodes and signal transmission circuit is as follows: the sensing electrodes and resistance row and column scanning circuit of the front pressure sensing module are integrated on the main flexible circuit board, and the extension circuit of the main flexible circuit board passes through the through hole of the internal partition of the base and is connected to the middle signal processing circuit; the sensing electrodes and resistance row and column scanning circuit of the top pressure sensing module are integrated on the top flexible circuit board, the top flexible circuit board is laid at the bottom of the top groove, and the extension circuit of the top flexible circuit board passes through the through hole of the bottom wall of the top groove and is connected to the main flexible circuit board; the interdigital electrode circuit of the top proximity sensing module is pasted on the outer surface of the top pressure contact encapsulation layer and is connected to the top flexible circuit board through the flexible extension circuit of the side fold; the electrode circuits of the four sensing units of the internal tangential force sensing module are the four horizontal flaps at the upper and lower ends of the main flexible circuit board.

[0029] Furthermore, in the mid-range signal processing circuit, the signal processing paths of each sensing module are as follows: the capacitance signal of the top proximity sensing module is directly input to the capacitance acquisition chip, converted into a digital signal, and then output; the resistance signals of the top pressure sensing module and the front pressure sensing module are converted into voltage signals by a resistance-to-voltage conversion circuit, and then converted into digital signals by an analog-to-digital conversion circuit; the Wheatstone bridge output voltage signal of the internal tangential force sensing module is directly input to the analog-to-digital conversion circuit and converted into a digital signal; all digital signals are transmitted to the external host computer interface, thereby driving the robotic arm control program to execute corresponding actions.

[0030] The present invention has the following advantages over the prior art: 1. This invention provides a multimodal flexible tactile finger for intelligent operation of power inspection robots. It integrates a proximity sensing module, a pressure sensing module, and a tangential force sensing module, providing the robot's end effector with a multimodal flexible tactile finger that has proximity perception capability, high-resolution array pressure perception capability, and tangential force perception capability. It is suitable for common tasks in power inspection operations such as button pressing, gripping, and plug insertion / removal. It can work collaboratively in the confined space and complex environment of the robot's power inspection operation scenario, monitor the interaction status between the robot's end effector and the object / obstacle to be operated in real time, enhance the environmental adaptability and fault prediction capability of the power inspection robot, and improve operational safety.

[0031] 2. This invention provides a multimodal flexible tactile finger for intelligent operation of power inspection robots. Both its top and front pressure sensing modules employ array-type resistive flexible pressure sensors. In this resistive flexible pressure sensor structure, the electrode layer and encapsulation layer adopt a segmented structure design with alternating hard and soft materials. The high-hardness encapsulation segment in the middle of the encapsulation layer is completely covered by the flexible elastic material segment in the middle of the electrode layer, concentrating strain in the high-conductivity layer region on the inner edge of the two rectangular electrode segments. When a pressure load is applied, the cracks in this high-conductivity layer preferentially propagate, leading to rapid rupture of the high-conductivity conductive path. Simultaneously, the low-conductivity layer begins to carry current, forming a two-dimensional macroscopic conductive path transition, achieving ultra-high sensitivity pressure sensing. Furthermore, the dual-strain layer structure design avoids rapid saturation of resistance change when the high-conductivity layer completely breaks. Under medium to high pressure loads, the low-conductivity layer gradually dominates the conductive process, maintaining high sensitivity while broadening the sensing range. Furthermore, instead of the traditional particle-filled three-dimensional conductive network, a two-dimensional layered structure is adopted to achieve deterministic control of the conductive path. This ensures that resistance changes depend solely on macroscopic changes in the conductive path, significantly improving sensor repeatability. The integrated sensor structure design eliminates the unstable void interface of traditional resistive flexible pressure sensors, further enhancing sensor repeatability.

[0032] 3. This invention provides a multimodal flexible tactile finger for intelligent operation of power inspection robots. A high-density front-side pressure sensing module is embedded laterally at the end of the finger, providing the power inspection system with high-density pressure distribution monitoring capabilities on the end-grip surface. During power inspection gripping operations, it provides the pose information of the object being gripped, determines whether the robotic arm's movement path conflicts with the safe movement path of the object, avoids damage to the object and the working environment, and significantly improves the system's operational safety.

[0033] 4. This invention provides a multimodal flexible tactile finger for intelligent operation of power inspection robots. An internal tangential force sensing module based on a full-bridge circuit is embedded laterally at the distal end, cleverly combined with a front pressure sensing module. Through a movable side pressure contact encapsulation layer and an edge stress concentration structure, the tangential force is transmitted to the tangential pressure sensitive unit, improving the sensitivity of the tangential force sensing module. During plug insertion and removal operations in power inspections, the tactile finger can monitor changes in tangential force and their rate of change in real time, accurately identifying states such as jamming and slippage, thus improving the success rate of insertion and removal operations and the safety of system operation.

[0034] 5. This invention provides a multimodal flexible tactile finger for intelligent operation of power inspection robots. By integrating a miniaturized, high-density interdigital electrode-type capacitive proximity sensor array at the top of the robot's end effector, it provides high-precision, short-range distance sensing capabilities for the robotic claw. In beyond-line-of-sight scenarios such as pressing operations during power inspections, it meets the high-precision positioning requirements of the robotic claw for precision components. Through real-time monitoring and feedback adjustment of the proximity array signals, it ensures an appropriate pressing path for the end effector, improving the success rate of inspection operations. Simultaneously, in confined spaces and complex operating environments, the proximity signals can provide pre-contact proximity distance warnings, avoiding accidental collisions between the end effector and other objects, further improving the safety of robot operations.

[0035] 6. This invention provides a multimodal flexible tactile finger for intelligent operation of power inspection robots. A high-density top pressure sensing module is integrated at the tip of the finger to detect changes in pressure in real time. In power inspection operation scenarios involving pressing, real-time monitoring of pressure distribution and magnitude accurately identifies operational states such as pressing position deviation, button self-locking, button limit, and pressing completion. This information serves as the basis for robotic arm motion control and end-effector posture adjustment, reducing the damage rate of the object being operated on and improving operational safety. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the present invention.

[0037] Figure 2 This is a three-dimensional exploded view of the top structure of the present invention.

[0038] Figure 3 This is a three-dimensional exploded view of the internal structure of the present invention.

[0039] Figure 4 This is a perspective view of the side pressure contact encapsulation layer in the front pressure sensing module and the internal tangential force sensing module of the present invention in the open state.

[0040] Figure 5 This is an exploded perspective view of the front pressure sensing module and the internal tangential force sensing module of the present invention.

[0041] Figure 6 This is a cross-sectional view of the resistive flexible pressure sensor of the present invention.

[0042] Figure 7 This is a schematic diagram of the crack propagation state of the resistive flexible pressure sensor of the present invention under pressure load.

[0043] Figure 8 This is a schematic diagram illustrating the sensing mechanism and local conductive path of the resistive flexible pressure sensor of the present invention.

[0044] Figure 9 This is the resistance relative change-pressure characteristic curve of the resistive flexible pressure sensor of the present invention.

[0045] Figure 10 This is for the repeatability test of the resistive flexible pressure sensor of the present invention.

[0046] Figure 11 This is the output voltage-tangential force characteristic curve of the resistive flexible pressure sensor of the present invention.

[0047] Figure 12 This is the proximity sensor's capacitance relative change-proximity distance characteristic curve.

[0048] Figure 13 This is a signal flow diagram of the multimodal flexible tactile finger of the present invention.

[0049] Figure 14 This is a schematic diagram of the circuit structure of the multimodal flexible tactile finger of the present invention.

[0050] Figure 15 This is a schematic diagram of the interdigital electrode structure of the top proximity sensing module of the present invention.

[0051] The diagram shows the following components: 1. Base; 2. Top proximity sensor module; 3. Top pressure sensor module; 4. Front pressure sensor module; 5. Internal tangential force sensor module; 6. Top groove; 7. Top pressure contact encapsulation layer; 8. Resistive flexible pressure sensor; 9. Side pressure contact encapsulation layer; 10. Low conductivity layer; 11. High conductivity layer; 12. Rectangular electrode segment; 13. Flexible elastic material segment; 14. Low hardness encapsulation segment; 15. High hardness encapsulation segment; 16. Main flexible circuit board; 17. Horizontal flap; 18. Elastic gasket; 19. Clearance groove; 20. Main rigid connection frame; 21. Main mesh hole; 22. Side pressure contact; 23. Top flexible circuit board; 24. Top rigid connection frame; 25. Top mesh hole; 26. Top pressure contact; 27. Internal signal acquisition circuit board; 28. Lower cover plate. Detailed Implementation

[0052] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments.

[0053] See Figures 1 to 6 This embodiment provides a multimodal flexible tactile finger for intelligent operation of power inspection robots, including a base 1, a top proximity sensing module 2 and a top pressure sensing module 3 on the top of the base, and a front pressure sensing module 4 and an internal tangential force sensing module 5 inside the base.

[0054] The top pressure sensing module 3 is a single-row pressure sensing array, including n resistive flexible pressure sensors 8, which are embedded in the top groove 6 opened on the top of the base. The top of the top pressure sensing module 3 is encapsulated by the top pressure contact encapsulation layer 7, which is exposed from the top groove 6.

[0055] The top proximity sensing module 2 is a single-row proximity sensing array, including n capacitive proximity sensors, which are laid on the top pressure contact encapsulation layer 7.

[0056] The front pressure sensing module 4 is an m×n pressure sensing array, including m×n resistive flexible pressure sensors 8, which are installed in the cavity inside the base. The front side of the front pressure sensing module 4 is encapsulated by a side pressure contact encapsulation layer 9, which is exposed from the front side of the base. Here, m represents the number of rows and n represents the number of columns. In this embodiment, both m and n are 4.

[0057] The internal tangential force sensing module 5 is installed in the internal cavity of the base and includes four resistive flexible pressure sensors 8 that make up the full-bridge electric bridge structure, distributed on the periphery of the front pressure sensing module 4.

[0058] The entire tactile finger is mounted on the gripper of the robot's electric two-finger gripper via a base. The internal cavity of the base is divided into upper and lower cavities. The front pressure sensing module 4 and the internal tangential force sensing module 5 are located in the upper cavity, while the internal signal acquisition circuit board 27 used for the mid-range signal processing circuit is located in the lower cavity, which is sealed by a lower cover plate 28.

[0059] The resistive flexible pressure sensor 8 includes an electrode layer, a high-conductivity layer 11, a low-conductivity layer 10, and an encapsulation layer stacked sequentially. The electrode layer consists of two spaced rectangular electrode segments 12 and a flexible elastic material segment 13 located between the two rectangular electrode segments. The electrode layer thickness is 100~500μm. In this embodiment, the overall size of the electrode layer is 4mm×4mm×0.3mm, the size of a single rectangular electrode segment is 4mm×1mm×0.3mm, the size of the intermediate flexible elastic material segment is 4mm×2mm×0.3mm, and the Shore hardness is 10A. The conductivity of the low-conductivity layer is no higher than 10 S·cm. -1 The stretchable length is not less than 50%, and the thickness of the low-conductivity layer is 20~200μm; in this embodiment, the thickness of the low-conductivity layer is 50μm, and the conductivity is approximately 1S·cm. -1 It can withstand a tensile length greater than 50%. The electrical conductivity of the high-conductivity layer is not less than 1000 S·cm. -1 The stretchable length is no more than 5%, and the thickness of the high-conductivity layer is 10~200μm; in this embodiment, the thickness of the high-conductivity layer is 30μm, and the conductivity is approximately 1100S·cm. -1 It will break at 1% of the tensile length. The encapsulation layer consists of two spaced low-hardness encapsulation segments 14 and a high-hardness encapsulation segment 15 located between the two low-hardness encapsulation segments. The Shore hardness of the low-hardness encapsulation segments is not greater than 30A, and the Shore hardness of the high-hardness encapsulation segments is not less than 70A. The high-hardness encapsulation segments can be completely covered by flexible elastic material segments. The thickness of the encapsulation layer is 300μm~1mm. In this embodiment, the Shore hardness of the high-hardness encapsulation segment is 70A, and the size is 4mm×1.4mm×0.3mm. The Shore hardness of the two low-hardness encapsulation segments is 20A, and the size is 4mm×1.3mm×0.3mm.

[0060] In this embodiment, the specific materials of each layer of the resistive flexible pressure sensor are as follows: The rectangular electrode segment 12 of the electrode layer is made of double-sided conductive copper foil with a thickness of 0.3 mm, which is bonded to the corresponding exposed copper pad area of ​​the FPCB; the high conductivity layer 11 is a thin film structure with a thickness of 30 μm, which is prepared by film formation and curing with PEDOT:PSS as the substrate and doped with 4 wt% of the electrical modifier ethylene glycol (EG) and 1 wt% of the adhesion enhancer KH-560 (γ-glycidyl etheroxypropyltrimethoxysilane); the low conductivity layer 10 is a thin film structure with a thickness of 50 μm, which is made of PDMS prepolymer as the matrix and doped with 0.2 wt% of single-walled carbon nanotubes (SWCNTs) and 0.05 wt% of the dispersant Triton. X-100 is obtained by mixing, dispersing, curing and molding; the flexible elastic material segment 13 of the electrode layer and the low hardness encapsulation segment 14 of the encapsulation layer are both made of silicone rubber with a Shore hardness of 20A by injection molding and curing, and the high hardness encapsulation segment 15 of the encapsulation layer is made of silicone rubber with a Shore hardness of 80A by curing and molding.

[0061] Figure 7 This diagram illustrates the crack propagation state of the high-conductivity layer in the resistive flexible pressure sensor fabricated in this embodiment under pressure load. In the resistive flexible pressure sensor, due to the alternating design of high-hardness and low-hardness regions in the encapsulation layer and electrode layer, the strain of the high-conductivity and low-conductivity layers is concentrated in the interval region between the upper and lower high-hardness portions under pressure load. The high-conductivity layer in this region gradually fractures and generates cracks under tensile stress. As the pressure load increases, the crack width in this region gradually expands, and the number of cracks gradually increases. Figure 8 This diagram illustrates the sensing mechanism and local conductivity path changes of the resistive flexible pressure sensor fabricated in this embodiment. As the crack in the high-conductivity layer propagates under pressure load, the sensor current transmission path gradually changes from the high-conductivity layer with high conductivity to the cracked portion flowing through the low-conductivity layer with low conductivity. Initially, the resistance of the uncracked portion is equal to the resistance R of the high-conductivity layer. H and low conductivity layer resistance R L Parallel connection, due to R H < <R L Total resistance R = R H ||R L ≈R H When a crack appears, the resistance of the cracked portion is equal to the resistance R of the high-conductivity layer. H1 R H2 With the low conductivity layer resistance R of the cracked part L1 The series connection of the two resistors results in a total resistance R' = R H1 +R L1 +R H2 >>R H As the pressure load increases, the cracks in the high-conductivity layer of the pressure sensor gradually propagate, causing the sensor resistance to rise rapidly.

[0062] Figure 9 The resistance-pressure characteristic curve of the resistive flexible pressure sensor prepared in this embodiment shows that the sensor has high sensitivity and a large sensing range. Within the pressure sensing range of 0~30N, the sensor sensitivity is approximately 4.65N. -1 linear correlation coefficient R 2 It is 0.98.

[0063] Figure 10 The results show the repeatability test of the resistive flexible pressure sensor prepared in this embodiment. It can be seen that during 2000 cyclic pressure loading / unloading cycles (pressure range 0~30N), the sensor output resistance did not fluctuate significantly, demonstrating stable electrical characteristics and good repeatability.

[0064] Figure 11The output voltage-tangential force characteristic curve of the tangential force sensor prepared in this embodiment is shown. It can be seen that the sensor has good tangential force sensing range and sensitivity, with a sensitivity of 0.365 V·N within the tangential force range of 0~6N. -1 The sensitivity is 0.026 V·N in the tangential force range of 6~23 N. -1 .

[0065] Figure 12 The capacitance relative change-proximity distance characteristic curve of the proximity sensor prepared in this embodiment is shown. It can be seen that the sensor has a significant capacitance relative change within 40mm, and can detect proximity distance within a 40mm range.

[0066] The specific arrangement of each sensing module on the base is as follows: The front pressure sensing module 4 is located on the front side of the main flexible circuit board 16. The upper and lower ends of the main flexible circuit board each have a set of horizontally extending forward mounting structures. Each set of horizontal mounting structures includes two horizontally arranged flaps 17. The four resistive flexible pressure sensors of the internal tangential force sensing module 5 are correspondingly located inside the four horizontal flaps. The main flexible circuit board 16 is surrounded by an elastic gasket 18 with an open front side, and the four horizontal flaps of the main flexible circuit board are exposed through clearance grooves 19 on the upper and lower sides of the elastic gasket 18. A main rigid connecting frame 20 is also provided within the area enclosed by the four resistive flexible pressure sensors of the internal tangential force sensing module. The main rigid connecting frame 20 has several main grid holes 21 arranged in an array. The m×n resistive flexible pressure sensors of the front pressure sensing module 4 are correspondingly located in the several main grid holes 21 of the main rigid connecting frame 20. The front pressure sensing module 4 has an m×n side pressure contact array on the rear side of the side pressure contact encapsulation layer 9, including m×n side pressure contacts 22. The m×n side pressure contacts 22 on the rear side of the side pressure contact encapsulation layer 9 are embedded one-to-one into several main grid holes 21 of the main rigid connection frame 20.

[0067] The top pressure sensing module 3 is disposed on the upper surface of the top flexible circuit board 23, which is disposed on two horizontal flaps 17 at the upper end of the main flexible circuit board 16. A top rigid connecting frame 24 is embedded in the top groove 6 of the base 1. The top rigid connecting frame 24 has a plurality of top grid holes 25 arranged in an array. The n resistive flexible pressure sensors of the top pressure sensing module 3 are correspondingly disposed in the plurality of top grid holes 25 of the top rigid connecting frame 24. The bottom of the top pressure contact encapsulation layer 7 of the top pressure sensing module 3 has a single-row top pressure contact array, including n top pressure contacts 26. The n top pressure contacts 26 at the bottom of the top pressure contact encapsulation layer 7 are correspondingly embedded in the plurality of top grid holes 25 of the top rigid connecting frame 24.

[0068] Figure 13 and Figure 14 These are the signal flow diagram and circuit design structure diagram of the multimodal flexible tactile finger prepared in this embodiment. The multimodal flexible tactile finger has a built-in signal acquisition circuit, which consists of two parts: a front-end sensing electrode and signal transmission circuit, and a mid-end signal processing circuit. The mid-end signal processing circuit uses an internal signal acquisition circuit board 27, which is embedded in the lower cavity inside the base and sealed by a lower cover plate 28. The mid-end signal processing circuit integrates a resistance-to-voltage conversion circuit, a row and column scanning control circuit, an analog-to-digital conversion circuit, and a capacitance acquisition chip, which is used to convert the analog signals of each sensing module into digital signals and transmit them to an external host computer. The front-end sensing electrode and signal transmission circuit are made of flexible circuit boards to realize the electrical connection between each sensing module and the mid-end signal processing circuit.

[0069] The specific layout of the front-end sensing electrodes and signal transmission circuit is as follows: The sensing electrodes and resistive row and column scanning circuit of the front pressure sensing module are integrated on the main flexible circuit board. The extended circuit of the main flexible circuit board passes through the through hole of the internal partition of the base and is connected to the mid-end signal processing circuit. The sensing electrodes and resistive row and column scanning circuit of the top pressure sensing module are integrated on the top flexible circuit board, which is laid at the bottom of the top groove. The extended circuit of the top flexible circuit board passes through the through hole in the bottom wall of the top groove and is connected to the main flexible circuit board. The interdigital electrode circuit of the top proximity sensing module (such as...) Figure 15 (As shown) It is pasted on the outer surface of the top pressure contact encapsulation layer and connected to the top flexible circuit board through the flexible extension circuit that is folded on the side; The electrode circuits of the four sensing units of the internal tangential force sensing module are the four horizontal flaps at the top and bottom of the main flexible circuit board.

[0070] In the mid-range signal processing circuit, the signal processing paths of each sensing module are as follows: the capacitance signal of the top proximity sensing module is directly input to the capacitance acquisition chip, converted into a digital signal, and then output; the resistance signals of the top pressure sensing module and the front pressure sensing module are converted into voltage signals by a resistance-to-voltage conversion circuit, and then converted into digital signals by an analog-to-digital conversion circuit; the Wheatstone bridge output voltage signal of the internal tangential force sensing module is directly input to the analog-to-digital conversion circuit and converted into digital signals; all digital signals are transmitted to the external host computer interface, thereby driving the robotic arm control program to execute corresponding actions.

[0071] Furthermore, the working mechanism of each module is as follows: (1) Top Proximity Sensing Module: The proximity sensor it contains has two sets of interdigitated electrodes arranged in an alternating pattern. When energized, a stable electric field distribution is formed between and around the electrodes, and a fixed mutual capacitance is formed between the two electrodes. When approaching an external object, the electric field line path and the dielectric constant of the medium in which the electric field is located are disturbed, and the change in the electric field coupling strength between the emitter and receiver leads to a change in the mutual capacitance value. This capacitance analog signal is directly transmitted to the capacitance acquisition chip on the mid-range signal processing circuit (internal signal acquisition circuit board), converted into a digital signal, and then transmitted to the external host computer via the IIC bus.

[0072] (2) Top pressure sensing module and front pressure sensing module: When there is no pressure load, the conductive path between the positive and negative electrodes of the resistive flexible pressure sensor is mainly the high-conductivity layer; when a pressure load is applied, the contacts in the rigid frame transmit the local normal stress to the corresponding pressure sensing unit. Under the action of stress, the strain of the flexible pressure sensor is concentrated in the high-conductivity layer area on the inner edge of the two rectangular electrode segments, causing cracks to form and propagate in the high-conductivity layer in this area. The conductive path changes from the high-conductivity layer to the low-conductivity layer, and the resistance of the sensing unit increases rapidly. This resistance change signal is transmitted to the mid-range signal processing circuit through the main flexible circuit board or the top flexible circuit board. It is converted into a voltage signal by the resistance-to-voltage conversion circuit, and then converted into a digital signal by the analog-to-digital conversion circuit. Finally, it is transmitted to the external host computer through the IIC bus to realize ultra-high sensitivity pressure sensing.

[0073] (3) Internal tangential force sensing module: The four resistive flexible pressure sensors of the tangential force sensing module form a closed loop as the four resistive arms of a Wheatstone bridge. When a tangential force is applied to the grasped object, the tangential force is transmitted to the main rigid connecting frame through the side pressure contacts, causing it to move tangentially and squeeze the resistive flexible pressure sensors and elastic pads on both sides. This causes the resistance of one side of the sensor to increase while the resistance of the other side remains unchanged, resulting in the bridge balance being broken and a voltage difference related to the magnitude of the tangential force being generated at the output. This voltage signal is directly input to the analog-to-digital conversion circuit of the intermediate signal processing circuit, converted into a digital signal, and then transmitted to the external host computer through the IIC bus.

[0074] The multimodal flexible tactile finger prepared in this embodiment is used in power line inspection operations. The intelligent operation task and workflow based on multimodal tactile signal feedback are as follows: (1) Install the multimodal flexible tactile finger on the fingertip of the two-finger gripper at the end of the robotic arm, adjust the initial state of the two-finger gripper according to the type of operation, and move the end of the robotic arm to the position of operation near the object to be operated; (2) Perform the corresponding operation according to the job type: (a) Pressing operation: During the pressing process, the distance and relative position between the end and the object to be operated (such as a button, key, or switch) are detected by the signal distribution of the proximity sensor module at the top. At the same time, real-time feedback and adjustment are provided to correct the pressing path and ensure safe contact. After contact, the pressure distribution on the contact surface is detected by the pressure sensor module at the top to confirm whether the end position meets the pressing conditions. During the pressing process, the pressing status (including pressing start, pressing completion, and over-pressing) is monitored by the pressure signal at the top to guide the robot to press with appropriate force. (b) Gripping operation: During the clamping process, the contact state between the fingertips of the grippers and the object to be worked is monitored in real time by the front pressure sensing module of the two tactile fingers; a small pressure gripping attempt is first performed, and the gripping state and posture (including relative position deviation, contact surface stability, and gripping center deviation) are judged based on the front pressure distribution. At the same time, the distance to the nearby platform is monitored by the top proximity sensing module to determine the safe movement range; after adjusting the posture, a large pressure gripping is performed, and the gripping force and stability are detected in real time by the front pressure distribution. (c) Insertion and Removal Operation: Based on stable clamping, the internal tangential force sensor module detects the tangential insertion and removal force during the removal process. Based on the signal characteristics, it identifies states such as jamming, slippage, and removal completion, and performs corresponding actions such as stopping the machine for adjustment, increasing the clamping force, and proceeding to the next operation. After moving to the position of the socket to be inserted, the internal tangential force sensor module detects the tangential force during the insertion process. Based on the signal characteristics, it identifies states such as jamming, slippage, and insertion completion, and performs corresponding actions such as emergency stop, increasing the clamping force, stopping the forward movement, and releasing the clamp. During the insertion process, the distance to the socket platform is monitored in real time by the top proximity sensor module to determine the safe movement range. (3) After the operation is completed, the robotic arm is reset and the mechanical gripper returns to its initial state.

[0075] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A multimodal flexible tactile finger for intelligent operation of power inspection robots, comprising a base, characterized in that: The base is equipped with a top proximity sensing module and a top pressure sensing module at the top, and a front pressure sensing module and an internal tangential force sensing module inside the base. The top pressure sensing module is a single-row pressure sensing array, including n resistive flexible pressure sensors, which are embedded in the top groove opened on the top of the base. The top of the top pressure sensing module is encapsulated by a top pressure contact encapsulation layer, which is exposed from the top groove. The top proximity sensing module is a single-row proximity sensing array, consisting of n capacitive proximity sensors, laid on the top pressure contact encapsulation layer; The front pressure sensing module is an m×n pressure sensing array, including m×n resistive flexible pressure sensors, which are installed in the cavity inside the base. The front side of the front pressure sensing module is encapsulated by a side pressure contact encapsulation layer, which is exposed from the front side of the base; where m represents the number of rows and n represents the number of columns. The internal tangential force sensing module is installed in the internal cavity of the base and includes four resistive flexible pressure sensors that make up the full-bridge structure, distributed on the periphery of the front pressure sensing module.

2. The multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 1, characterized in that: The resistive flexible pressure sensor includes an electrode layer, a high-conductivity layer, a low-conductivity layer, and an encapsulation layer stacked sequentially. The electrode layer consists of two spaced rectangular electrode segments and a flexible elastic material segment located between the two rectangular electrode segments; the conductivity of the low-conductivity layer is no higher than 10 S·cm. -1 The stretchable length is not less than 50%; the electrical conductivity of the high-conductivity layer is not less than 1000 S·cm. -1 The stretchable length is no more than 5%; the encapsulation layer consists of two spaced low-hardness encapsulation segments and a high-hardness encapsulation segment located between the two low-hardness encapsulation segments. The Shore hardness of the low-hardness encapsulation segment is no greater than 30A, the Shore hardness of the high-hardness encapsulation segment is no less than 70A, and the high-hardness encapsulation segment can be completely covered by the flexible elastic material segment.

3. The multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 2, characterized in that: The electrode layer of the resistive flexible pressure sensor has a thickness of 100~500μm, the low conductivity layer has a thickness of 20~200μm, the high conductivity layer has a thickness of 10~200μm, and the encapsulation layer has a thickness of 300μm~1mm.

4. The multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 2, characterized in that: The front pressure sensing module is located on the front side of the main flexible circuit board. The upper and lower ends of the main flexible circuit board are respectively provided with a set of horizontally extending forward sets of horizontal mounting structures. Each set of horizontal mounting structures includes two horizontal flaps arranged on the left and right. The four resistive flexible pressure sensors of the internal tangential force sensing module are correspondingly set inside the four horizontal flaps. The main flexible circuit board is wrapped with an elastic gasket with an open front side, and the four horizontal flaps of the main flexible circuit board are exposed from the clearance grooves opened on the upper and lower sides of the elastic gasket. The area enclosed by the four resistive flexible pressure sensors of the internal tangential force sensing module is also provided with a main rigid connecting frame. The main rigid connecting frame has several grid holes arranged in an array. The m×n resistive flexible pressure sensors of the front pressure sensing module are correspondingly set in the several grid holes of the main rigid connecting frame.

5. The multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 4, characterized in that: The top pressure sensing module is mounted on the upper surface of the top flexible circuit board, which is mounted on two horizontal flaps at the upper end of the main flexible circuit board.

6. The multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 4, characterized in that: The front pressure sensing module has an m×n side pressure contact array on the rear side of the side pressure contact encapsulation layer, including m×n side pressure contacts. The m×n side pressure contacts on the rear side of the side pressure contact encapsulation layer are embedded one-to-one into several grid holes of the main rigid connection frame.

7. A multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 5, characterized in that: A top rigid connecting frame is embedded in the top groove of the base. The top rigid connecting frame has a number of grid holes arranged in an array. The n resistive flexible pressure sensors of the top pressure sensing module are respectively set in the number of grid holes of the top rigid connecting frame. The top pressure sensing module has a single-row top pressure contact array at the bottom of the top pressure contact encapsulation layer, including n top pressure contacts. The n top pressure contacts at the bottom of the top pressure contact encapsulation layer are embedded one-to-one into several grid holes in the top rigid connection frame.

8. A multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 5, characterized in that: The multimodal flexible tactile finger has a built-in signal acquisition circuit, which consists of two parts: a front-end sensing electrode and signal transmission circuit, and a mid-end signal processing circuit. The mid-range signal processing circuit adopts an internal signal acquisition circuit board, which is embedded in the lower cavity inside the base and sealed by the lower cover plate. The mid-range signal processing circuit integrates a resistor-to-voltage conversion circuit, a row and column scanning control circuit, an analog-to-digital conversion circuit, and a capacitance acquisition chip, which are used to convert the analog signals of each sensing module into digital signals and transmit them to an external host computer. The front-end sensing electrodes and signal transmission circuits are made of flexible circuit boards to realize the electrical connection between each sensing module and the mid-end signal processing circuit.

9. A multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 8, characterized in that, The specific layout of the front-end sensing electrodes and signal transmission circuit is as follows: The sensing electrodes and resistive row and column scanning circuit of the front pressure sensing module are integrated on the main flexible circuit board, and the extension circuit of the main flexible circuit board is connected to the mid-end signal processing circuit through the through hole of the internal partition of the base. The sensing electrodes and resistive row and column scanning circuit of the top pressure sensing module are integrated on the top flexible circuit board, which is laid at the bottom of the top groove. The extended circuit of the top flexible circuit board passes through the through hole in the bottom wall of the top groove and is connected to the main flexible circuit board. The interdigitated electrode circuit of the top proximity sensing module is attached to the outer surface of the top pressure contact encapsulation layer and connected to the top flexible circuit board through a flexible extension circuit that is folded on the side. The electrode circuits of the four sensing units of the internal tangential force sensing module are the four horizontal flaps at the top and bottom of the main flexible circuit board.

10. A multimodal flexible tactile finger for intelligent operation of power inspection robots as described in claim 8, characterized in that: In the mid-range signal processing circuit, the signal processing paths of each sensing module are as follows: The capacitive signal from the top proximity sensing module is directly input to the capacitance acquisition chip, converted into a digital signal, and then output. The resistance signals from the top pressure sensing module and the front pressure sensing module are converted into voltage signals by a resistance-to-voltage conversion circuit, and then converted into digital signals by an analog-to-digital conversion circuit. The Wheatstone bridge output voltage signal of the internal tangential force sensing module is directly input to the analog-to-digital converter circuit to be converted into a digital signal; All digital signals are transmitted to an external host computer interface, which in turn drives the robotic arm control program to execute corresponding actions.

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