Integrated multi-mode tactile perception dexterous finger and robot

Abstract

The invention relates to an integrated multi-mode tactile perception dexterous finger and a robot, and belongs to the technical field of robot sensing. Comprising a flexible printed circuit which comprises a Wheatstone bridge circuit, a switch chip, a microcontroller, a rigid sensing unit and a flexible triboelectric sensing unit electrode; the rigid sensing unit comprises a temperature and pressure sensing chip; the Wheatstone bridge circuit is connected with the switch chip, and the switch chip is connected with the microcontroller; the microcontroller is respectively connected with the sensing chip and the flexible friction electric sensing unit electrode; the dexterous finger shell comprises a first shell and a second shell; the first shell and the second shell are connected to form a containing cavity, and the flexible printed circuit is arranged in the containing cavity. And the flexible friction electric sensing unit friction layers are arranged on the surfaces of the first shell and the second shell and are connected with the rigid sensing units and the flexible friction electric sensing unit electrodes. The multi-mode touch sensing device has a multi-mode sensing function, can recognize various touch modes, adopts an integrated mode, and enhances reliability and sensing precision.

Description

Technical Field

[0001] This invention relates to the field of robot sensing technology, and in particular to a dexterous finger and robot that integrates multimodal tactile sensing. Background Technology

[0002] Tactile perception is a core function for robotic dexterous hands to achieve autonomous operation and complex grasping tasks. As a multi-fingered, multi-degree-of-freedom end effector, the demand for tactile perception in dexterous hands is constantly increasing with the development of robotics technology. Tactile sensors, as the direct interaction medium between the dexterous hand and the target object, can provide crucial information such as material type, pressure, and temperature at the contact point, laying the foundation for multi-finger coordinated operation. In fields such as industrial assembly, medical assistance, and human-computer interaction, accurate tactile perception is of great significance for the precision manipulation of dexterous hands.

[0003] However, existing tactile sensor technology has many shortcomings in applications for robotic dexterity fingers. Traditional sensors are often limited to single or a few modes, capable of detecting only single parameters such as force or temperature. For example, force sensors based on strain gauges or capacitance can detect the magnitude of contact force, while temperature sensors based on thermistors can sense temperature changes. These sensors cannot simultaneously detect multiple parameters such as three-dimensional force, temperature, material type, roughness, or slippage, making it difficult to meet the complex perception needs of robots in dynamic and changing environments. Furthermore, existing sensors mostly use surface mounting, which is not only susceptible to interference from external factors (such as wear, humidity, and dust), leading to low repeatability and reliability, but also increases the size and complexity of the system due to the need for external signal processing circuitry. Long signal paths are prone to noise and crosstalk, further reducing perception accuracy and limiting the flexibility of finger movement and the realization of compact designs.

[0004] Although related research has attempted to improve sensing capabilities by increasing the number of sensors or optimizing their layout, these methods have not yet solved the problems of multimodal sensing and integrated operation. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the limitations of existing tactile sensors, such as single function, narrow sensing range, limited integration method, and low sensing reliability.

[0006] In a first aspect, to solve the above-mentioned technical problems, the present invention provides an integrated multimodal tactile sensing dexterous finger, comprising: A flexible printed circuit includes a Wheatstone bridge circuit, a switching chip, a microcontroller, a rigid sensing unit, and flexible triboelectric sensing unit electrodes; the rigid sensing unit includes a sensing chip; the Wheatstone bridge circuit is connected to the switching chip, and the switching chip is connected to the microcontroller; the microcontroller is connected to the sensing chip and the flexible triboelectric sensing unit electrodes respectively. The dexterous finger housing includes a first housing and a second housing; the first housing and the second housing are connected to form a receiving cavity, and the flexible printed circuit is built into the receiving cavity; the first housing has a first notch, and the second housing has a second notch, and the first notch and the second notch form an opening; A flexible triboelectric sensing unit friction layer is disposed on the outer surface of the first housing and the second housing; the flexible triboelectric sensing unit friction layer is connected to the rigid sensing unit and the flexible triboelectric sensing unit electrode through the opening.

[0007] In one embodiment of the present invention, the rigid sensing unit further includes a flexible force transmission layer and a package shell; the flexible force transmission layer has a flexible force transmission cylinder on the side facing the package shell, and the surface of the package shell facing the flexible force transmission layer has a central through hole, through which the flexible force transmission cylinder passes and engages with the sensing chip.

[0008] In one embodiment of the present invention, the side of the encapsulation shell away from the flexible force transmission layer is bottomless and connected to the flexible printed circuit board to form a cavity, and the sensing chip is disposed in the cavity.

[0009] In one embodiment of the present invention, the flexible force transmission layer is connected to the friction layer of the flexible triboelectric sensing unit.

[0010] In one embodiment of the present invention, the sensing chip includes a temperature-sensitive resistor strip, a plurality of varistor strips, a plurality of straight-bridge thin films, and a plurality of chip electrodes; the varistor strips are disposed above the straight-bridge thin films.

[0011] In one embodiment of the present invention, the Wheatstone bridge circuit includes a plurality of decoupling capacitors, a first operational amplifier and a second operational amplifier; the first operational amplifier is connected to the second operational amplifier; and the second operational amplifier is connected to at least one of the decoupling capacitors.

[0012] In one embodiment of the present invention, the flexible printed circuit further includes an external communication interface, one end of which is connected to the microcontroller; the external communication interface is disposed on the outside of the dexterous finger shell.

[0013] In one embodiment of the present invention, one end of the dexterous finger shell is provided with a connecting seat for pin mounting.

[0014] In one embodiment of the present invention, the material of the friction layer of the flexible triboelectric sensing unit is a composite material of highly electronegative polytetrafluoroethylene powder and polydimethylsiloxane solution.

[0015] Secondly, to solve the above-mentioned technical problems, the present invention provides a robot, including the aforementioned integrated multimodal tactile sensing dexterous finger.

[0016] Compared with the prior art, the above-described technical solution of the present invention has the following advantages: (1) The integrated multimodal tactile sensing dexterous finger and robot described in this invention achieves accurate detection of various physical quantities such as temperature, pressure, and triboelectric charge by fusing rigid sensing units and flexible triboelectric sensing units, thus expanding the application range and improving operational flexibility. This rigid-flexible coupling design effectively overcomes the shortcomings of traditional flexible force sensors in terms of consistency and stability. At the same time, the flexible triboelectric sensing unit on the finger surface can surpass the limitations of rigid sensors and achieve accurate recognition of multiple tactile modalities.

[0017] (2) The integrated design of the sensing chip with the friction layer and electrodes of the flexible triboelectric sensing unit in this invention not only makes the sensor structure more compact but also ensures high sensitivity and accuracy. Furthermore, the flexible printed circuit board design integrates a switching chip, a microcontroller, and a Wheatstone bridge circuit; the interconnection of these key components provides powerful signal processing capabilities. The connection between the microcontroller and multiple sensing chips and the electrodes of the flexible triboelectric sensing unit ensures accurate signal acquisition, amplification, and conversion.

[0018] (3) In this invention, both the sensing chip and the electrodes of the flexible triboelectric sensing unit are integrated into a flexible printed circuit board. This modular design not only facilitates system upgrades but also eliminates the need for external circuitry. The friction layer of the flexible triboelectric sensing unit is located on the outer surface of the dexterous finger shell, which optimizes the sensor's interaction with the external environment. The cavity formed by the first and second shells provides internal space for the flexible printed circuit board, saving external space and facilitating the integration of the overall structure. Attached Figure Description

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a structural diagram of a dexterous finger integrating multimodal tactile sensing in a preferred embodiment of the present invention; Figure 2 This is a schematic diagram of an integrated multimodal tactile sensing dexterous finger explosion in a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of a rigid-flexible coupled multimodal sensor structure in a preferred embodiment of the present invention; Figure 4 This is a schematic diagram of the silicon-based MEMS sensing unit structure in a preferred embodiment of the present invention; Figure 5 This is a schematic diagram of the silicon-based MEMS temperature and pressure sensing chip structure in a preferred embodiment of the present invention; Figure 6 This is a schematic diagram of the flexible triboelectric sensing unit structure in a preferred embodiment of the present invention; Figure 7 This is a partial schematic diagram of the FPC integrated circuit in a preferred embodiment of the present invention.

[0020] Explanation of reference numerals in the accompanying drawings: 1. External communication interface; 2. Connector; 3. Dexterous finger shell; 31. First shell; 32. Second shell; 4. FPC integrated circuit; 5. Flexible triboelectric sensing unit friction layer; 6. Flexible triboelectric sensing unit electrode; 7. Rigid sensing unit; 8. Flexible force transmission layer; 9. Encapsulation shell; 10. Sensing chip; 11. Flexible force transmission cylinder; 12. Central through hole; 13. Thermosensitive resistor strip; 14. Varistor strip; 15. Straight bridge thin film; 16. Solder pad. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0022] Example 1: Reference Figures 1 to 2 As shown, an embodiment of the present invention provides a dexterous finger integrating multimodal tactile sensing, comprising: The flexible printed circuit includes a Wheatstone bridge circuit, a switching chip, a microcontroller, a rigid sensing unit 7, and flexible triboelectric sensing unit electrodes 6; the rigid sensing unit 7 includes a sensing chip 10; the Wheatstone bridge circuit is connected to the switching chip, and the switching chip is connected to the microcontroller; the microcontroller is connected to the sensing chip 10 and the flexible triboelectric sensing unit electrodes 6 respectively. The dexterous finger housing 3 includes a first housing 31 and a second housing 32; the first housing 31 and the second housing 32 are connected to form a receiving cavity, and a flexible printed circuit is built into the receiving cavity; the first housing 31 is provided with a first notch, and the second housing 32 is provided with a second notch, and the first notch and the second notch form an opening; The friction layer of the flexible triboelectric sensing unit is disposed on the outer surface of the first housing 31 and the second housing 32; the friction layer 5 of the flexible triboelectric sensing unit is connected to the rigid sensing unit 7 and the flexible triboelectric sensing unit electrode 6 through an opening.

[0023] This invention provides an integrated multimodal tactile sensing dexterous finger. By integrating the sensing chip in a rigid sensing unit with the friction layer and electrodes of a flexible triboelectric sensing unit, the entire sensor structure becomes more compact while ensuring good sensitivity and accuracy. Furthermore, the flexible printed circuit design includes a switching chip, a microcontroller, and a Wheatstone bridge circuit. These components are interconnected, providing the dexterous finger with powerful signal processing capabilities. The connection between the microcontroller and the sensing chip and the electrodes of the flexible triboelectric sensing unit enables precise signal acquisition, amplification, and conversion. The integration of the sensing chip and the electrodes of the flexible triboelectric sensing unit within the flexible printed circuit eliminates the need for external circuitry and facilitates routine maintenance. The friction layer of the flexible triboelectric sensing unit is disposed on the outer surface of the dexterous finger's shell, allowing the sensor to interact better with the external environment. The cavity formed by the first and second shells provides internal space for the flexible printed circuit, saving external space and facilitating overall structural integration. This invention integrates key components within the dexterous finger's shell, reducing the impact of the external environment on sensor performance and thus improving stability and reliability during use. This design is suitable for a variety of complex application scenarios and can meet the requirements for high-precision and high-reliability sensors.

[0024] Specifically, the components of the dexterous finger include a rigid-flexible coupled multimodal sensor, a flexible printed integrated circuit (FPC integrated circuit 4), and a dexterous finger shell 3. (Refer to...) Figure 3 As shown, the rigid-flexible coupled multimodal sensor includes a rigid sensing unit 7 and a flexible triboelectric sensing unit. The dexterous finger housing 3 includes a first housing 31 and a second housing 32, and the FPC integrated circuit 4 is equipped with an external communication interface 1 and related electronic components. To improve the dexterous finger's flexibility and maintainability, all components are designed to be detachable. This design not only facilitates routine maintenance of functional modules but also allows for future technology upgrades and component replacement, thereby extending the dexterous finger's lifespan and improving its adaptability.

[0025] This invention, by combining a rigid sensing unit and a flexible triboelectric sensing unit, enables the detection of various physical quantities, such as temperature, pressure, and triboelectric charge, thereby expanding its application range and enhancing its flexibility. The rigid-flexible coupled multimodal sensor design overcomes the shortcomings of poor consistency and stability found in flexible force sensors. The flexible triboelectric sensing unit, in turn, overcomes the limitations of rigid sensors, enabling the recognition of multiple tactile modalities.

[0026] Specifically, refer to Figure 3As shown, the FPC integrated circuit 4 includes multiple rigid sensing units 7, each of which integrates a sensing chip 10. Taking a dual-chip layout as an example, two identical rigid sensing units can be used, installed on the fingertip and finger pad of a dexterous finger, respectively. This layout enables differentiated sensing of force and temperature. Furthermore, this dual-chip design of the fingertip and finger pad can adapt to various application scenarios, such as touch, pinching, and tapping, effectively overcoming the shortcomings of flexible force sensors in terms of consistency and stability, thereby improving the sensor's performance and reliability.

[0027] Furthermore, in this embodiment of the invention, the rigid sensing unit 7 is preferably a silicon-based MEMS sensing unit 7. Correspondingly, the sensing chip 10 is preferably a silicon-based MEMS temperature and pressure sensing chip 10.

[0028] Furthermore, referring to Figure 4 As shown, the core components of the silicon-based MEMS sensing unit 7 include a flexible force transmission layer 8, a package shell 9, and a silicon-based MEMS temperature and pressure sensing chip 10. The flexible force transmission layer 8 has a flexible force transmission cylinder 11 on one side, while the package shell 9 has a central through-hole 12 on its surface. The flexible force transmission layer 8 is preferably a rectangular thin-layer structure. The flexible force transmission cylinder 11 is positioned on the side facing the package shell 9 and precisely matches the central through-hole 12, effectively transmitting externally applied forces to the silicon-based MEMS temperature and pressure sensing chip 10. The package shell 9 has a hollow rectangular structure. The side facing the flexible force transmission layer 8 has a bottom, and the central through-hole 12 is located on this surface. The other side is bottomless and fixed to the circuit board containing the FPC integrated circuit 4, forming a cavity capable of accommodating the silicon-based MEMS temperature and pressure sensing chip 10. The height of this cavity is not less than the height of the silicon-based MEMS temperature and pressure sensing chip 10 to ensure adequate protection of the chip. The central through-hole 12 is coaxial with the central hole of the silicon-based MEMS temperature and pressure sensing chip 10, allowing the flexible force transmission cylinder 11 to directly contact the silicon-based MEMS temperature and pressure sensing chip 10 through the central through-hole 12, thereby achieving effective force transmission. Furthermore, the flexible force transmission layer 8 is in contact with the friction layer 5 of the flexible triboelectric sensing unit.

[0029] Furthermore, referring to Figure 5 As shown, the silicon-based MEMS temperature and pressure sensing chip 10 includes a thermistor strip 13, multiple varistor strips 14, multiple straight-bridge thin films 15, multiple chip electrodes, and other devices, wherein the varistor strips 14 are disposed above the straight-bridge thin films 15. The silicon-based MEMS temperature and pressure sensing chip 10 is electrically connected to the FPC integrated circuit 4 through metal pins, and its surface is provided with multiple pads 16 for detecting the resistance changes of the thermistor strip 13 and the varistor strips 14 (in... Figure 5In the diagram, S1 to S4 represent the resistance of the varistor strip 14. For example, the silicon-based MEMS temperature and pressure sensing chip 10 has 10 pads 16 on its surface, of which 2 pads 16 are used to detect the resistance change of the temperature-sensitive resistor strip 13 and 8 pads 16 are used to detect the resistance change of the varistor strip 14. The temperature-sensitive resistor strips 13 and hollow straight-bridge thin films 15 are evenly distributed in a circular shape on the side of the silicon-based MEMS temperature and pressure sensing chip 10 away from the FPC integrated circuit board, and two varistor strips 14 are set on each straight-bridge thin film 15. The hollow straight-bridge thin film 15 structure can sensitively capture minute deformations, and the resistance values ​​of the varistor strips 14 and the temperature-sensitive resistor strips 13 change precisely with the pressure and temperature of the finger. By analyzing the initial resistance value and the change value, load and temperature information can be accurately obtained. In addition, the size of the silicon-based MEMS temperature and pressure sensing chip 10 can be set to 2mm × 2mm. The number of straight-bridge type thin films 15 can be 4, and the number of varistor strips can be 8 (2x4).

[0030] Specifically, refer to Figure 6 As shown, the flexible triboelectric sensing unit includes a flexible triboelectric sensing unit friction layer 5 and multiple flexible triboelectric sensing unit electrodes 6. The triboelectric sensing unit friction layer 5 is fabricated using a composite material of highly electronegative polytetrafluoroethylene (PTFE) powder and polydimethylsiloxane (PDMS) solution, which is then fixed to the upper surface of the dexterous finger shell 3 through a potting process. This choice of composite material not only ensures excellent triboelectric properties but also endows it with good flexibility and durability, enabling it to adapt to various touch and pressure changes. Therefore, the flexible triboelectric sensing unit friction layer 5 on the finger surface can surpass the functional limitations of traditional rigid sensors, achieving accurate recognition of multiple tactile modalities.

[0031] Furthermore, the rigid sensing unit 7 and the flexible triboelectric sensing unit electrode 6 are integrated in a stacked design, both within the FPC integrated circuit 4. The FPC integrated circuit 4 enables the coordinated acquisition of resistance and triboelectric signals, achieving multimodal tactile perception.

[0032] Furthermore, the flexible triboelectric sensing unit operates on the principle of triboelectric effect and electrostatic induction. When a finger comes into contact with an external object, the friction layer 5 of the flexible triboelectric sensing unit generates a triboelectric signal, which is captured by the flexible triboelectric sensing unit electrode 6 on the FPC integrated circuit 4. The high electronegativity of this friction layer enables it to generate significant triboelectric signals when in contact with various materials, supporting multimodal sensing functions.

[0033] Specifically, the FPC integrated circuit 4 includes an external communication interface 1, a switching chip, a microcontroller, a Wheatstone bridge circuit, and related electronic components. The external communication interface 1 is used for signal transmission and power supply; one end is connected to the microcontroller, and the other end is connected to external devices. The switching chip controls the selection of signal paths, enabling switching between different sensor signals. The microcontroller processes and analyzes the acquired signals and transmits data through the external communication interface 1. The Wheatstone bridge circuit converts the resistance changes of the sensors into voltage signals for subsequent processing.

[0034] In embodiments of the present invention, the external communication interface 1 is preferably a 7-pin × 0.5mm specification. The FPC integrated circuit 4, the electrodes of the silicon-based MEMS sensor chip 10, and the electrodes of the flexible triboelectric sensing unit 6 cooperate with each other to achieve the recognition of multiple tactile modalities. The switching chip is preferably a MAX4617EUE, whose low on-resistance and fast switching capability ensure efficient and real-time signal transmission, while its low power consumption and high stability enable it to operate reliably in complex environments. The microcontroller is preferably a PIC16F1825, which has rich peripheral interfaces and powerful processing capabilities, enabling it to efficiently execute complex signal processing tasks. Its low power consumption design and user-friendly development environment further enhance the overall performance and development efficiency of the dexterous finger.

[0035] Furthermore, referring to Figure 7 As shown, in the Wheatstone bridge circuit, power is supplied through VCC, and the circuit reference point is formed through ground (GND). To ensure power supply stability and reduce noise, the circuit includes multiple decoupling capacitors (such as C1, C2, C3, and C4), a first operational amplifier, and a second operational amplifier. The first operational amplifier is connected to the second operational amplifier; the second operational amplifier is connected to one of the decoupling capacitors (such as C3). In this embodiment of the invention, the first operational amplifier is preferably OP07, and the second operational amplifier is preferably AD620.

[0036] Furthermore, the output of operational amplifier OP07 is connected to ground via resistor R7, forming a voltage follower configuration to provide a stable reference voltage for operational amplifier AD620. Operational amplifier AD620 is configured as a differential amplifier to amplify the sensing unit signal selected by the analog switch. Additionally, all operational amplifier power supply pins are connected to the circuit power supply to ensure proper operation.

[0037] Furthermore, the circuit includes multiple resistors (R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11) for voltage division, current limiting, biasing, and decoupling functions to ensure circuit stability and signal accuracy. Resistors R1 and R2 form a voltage divider circuit to output a specified stable voltage; resistors R6 and R7 also form a voltage divider circuit, similarly used to output a specified stable voltage. Resistors R8, R9, R10, and R11 are used for subsequent signal conditioning. Specifically, resistors R8, R10, and R11 are connected in series as a reference resistor to adjust the input voltage of the operational amplifier AD620; while resistor R9 is used to adjust the amplification factor of the operational amplifier AD620. The ultimate goal of these adjustments is to ensure that the amplified output voltage of the AD620 falls within the acceptable range for the microcontroller.

[0038] for Figure 7 It should be noted that wires marked with the same symbol in the diagram indicate that they are connected to each other. For example, Figure 7 The marking "R8 1" on the left side of resistor R11, and also below resistor R8, indicates that resistors R11 and R8 are connected. Similarly, the MAX4617EUE switch chip is marked with C1, C2, and C3 (not representing capacitor symbols), and the PIC16F1825 microcontroller is also marked with C1, C2, and C3, indicating that the corresponding markings are interconnected. This marking method aims to simplify circuit diagrams, reduce visual complexity, and make the circuit connections clearer.

[0039] The Wheatstone bridge circuit described above is designed to precisely control analog switches via a microcontroller, selecting and amplifying different input signals, and then outputting the processed signals to the microcontroller for further analysis and processing. This structure not only improves the flexibility of signal processing but also enhances overall stability and reliability.

[0040] Specifically, refer to Figure 7 As shown, taking a dual-chip layout with two identical rigid sensing units 7 as an example, the working principle of the FPC integrated circuit 4 is described. Specifically, the X0-X7 pins of the switch chip are connected to resistors S1-S8 of the silicon-based MEMS sensor chip 10, respectively. The A, B, and C control pins of the switch chip are connected to the RC0, RC1, and RC2 pins of the microcontroller to control the switch chip. It should be noted that the reference... Figure 5As shown, each silicon-based MEMS sensor chip 10 contains resistors S1 to S4. To more clearly distinguish the resistors on the two sensor chips, the resistors S1 to S4 on the second silicon-based MEMS sensor chip are labeled S5 to S8 respectively. This labeling method helps avoid confusion when describing and analyzing the circuit, ensuring that each resistor can be accurately identified and referenced. The microcontroller selects the signal input channel (X0-X7) of any one of the resistors S1-S8 by controlling the level states of the A, B, and C pins of the switching chip. The selected resistor signal is sent to the pre-designed Wheatstone bridge circuit through the common output terminal X of the switching chip. After bridge processing, the resistance change is converted into a voltage difference, and the final output signal is connected to the RC3 pin of the microcontroller. Through signal amplification, the piezoresistive information changes of the 8 straight bridge arrays can generate three-dimensional force information. Furthermore, the FPC integrated circuit 4 extends to the outside of the finger, leaving only 7 pins with a spacing of 0.5mm, namely VCC, GND, RA0, RA1, RA3, RX, and TX. VCC and GND are used for power supply; RA0, RA1, and RA3 pins are used for programming the PIC16F1825 microcontroller via the ICSP interface; RX and TX pins are used for serial communication with external devices. Furthermore, the flexible triboelectric sensing unit electrode 6 is directly connected to the microcontroller's RA2 pin. When the flexible triboelectric sensing unit's friction layer 5 (i.e., the surface of the dexterous finger) comes into contact with an object, the generated triboelectric signal is transmitted through the electrodes to the microcontroller for processing, and the triboelectric signal is output in real time.

[0041] Specifically, refer to Figure 1 As shown, the surface shape of the dexterous finger shell 3 is set as an arc structure to better simulate the natural bending shape of a human finger. The flexible triboelectric sensing unit friction layer 5 is cleverly arranged on the outer arc surface, thereby ensuring that the sensor can flexibly interact with the contact surface and achieve efficient triboelectric charge sensing. The first shell 31 and the second shell 32 are respectively provided with notches. When the first shell 31 and the second shell 32 are spliced ​​together, the two notches form an opening, which can expose some components of the FPC integrated circuit 4 (such as the flexible force transmission layer 8, the flexible triboelectric sensing unit electrode 6, etc.). Through this opening, the flexible force transmission layer 8 can make contact with the flexible triboelectric sensing unit friction layer 5.

[0042] Furthermore, one end of the dexterous finger housing 3 is provided with a connecting seat 2, which has multiple mounting holes for pin mounting, thereby achieving a reliable connection between the finger and the mechanical structure. For example... Figure 2As shown, both the first outer shell 31 and the second outer shell 32 are provided with a connecting seat 2 at the same end, so that when the two outer shells are spliced ​​together, a complete connecting part can be formed. In this embodiment, the connecting seat 2 of the first outer shell 31 and the second outer shell 32 are provided with two mounting holes, and two pins are inserted into the corresponding mounting holes.

[0043] Specifically, the assembly steps for each component of the dexterous finger are as follows: First, a silicon-based MEMS sensing unit 7 and related electronic components are integrated onto the FPC integrated circuit 4. Then, the FPC integrated circuit 4 is folded and embedded into the dexterous finger shell 3. Figure 2 This shows the folded state of the FPC integrated circuit 4. Figure 3 The image shows the folded state of the FPC integrated circuit 4. During the embedding process, the two sides of the circuit board where the flexible force transmission layer 8 and the flexible triboelectric sensing unit electrode 6 are located are tightly bonded to the corresponding notches of the first housing 31 and the second housing 32, respectively, and fixed with a special adhesive. Furthermore, only a 7-pin × 0.5mm external communication interface 1 extends to the outside of the dexterous finger housing 3 for signal transmission and power supply. All other components are fully integrated inside the finger. After assembly, a PTFE / PDMS composite solution is poured into the opening of the dexterous finger housing 3, and after curing, a stable flexible triboelectric sensing unit friction layer 5 is formed, achieving the final encapsulation of the dexterous finger. In addition, the dexterous finger can achieve quick and reliable modular connection with other mechanical structures via the connector 2.

[0044] This invention embeds the sensor and circuitry inside the finger, shielding it from external interference (such as humidity and dust) and improving reliability and wear resistance. Zero surface footprint allows for the integration of more complex drive structures (such as multi-jointed tendons), enhancing dexterity. Simultaneously, the shorter signal path reduces noise interference and improves data accuracy. The finger's dimensions are only 2cm × 1cm × 1.5cm, close to a human finger, and the silicon-based MEMS temperature and pressure sensing chip 10 is only 2mm × 2mm, supporting modular adaptation to different platforms.

[0045] Specifically, the dexterous finger described in this embodiment of the invention has functions of object interaction, three-dimensional force detection, temperature detection, proximity detection, material type detection, roughness detection, slippage state detection, and circuit detection. The working principle of having the above functions is as follows: When a dexterous finger interacts with an object: through the rigid-flexible coupling synergy of the silicon-based MEMS temperature and pressure chip 10 and the flexible triboelectric sensing unit, high-precision detection of a variety of physical parameters is achieved.

[0046] 3D Force Detection Principle: The silicon-based MEMS temperature and pressure sensing chip 10 achieves 3D force (X, Y, Z directions) detection through its internal straight-bridge structure. Each silicon-based MEMS temperature and pressure sensing chip 10 contains four straight bridges, each integrating a piezoresistive element. When an external force is applied to a dexterous finger, the force is transmitted to the straight bridges through the flexible force transmission layer 8, causing them to deform. The encapsulation shell 9 reduces the force on the silicon-based MEMS temperature and pressure sensing chip 10, thereby protecting the fragile silicon-based bridge structure. Under normal loads, each piezoresistive straight bridge bends synchronously, and the resistance shifts equally. The normal force can be estimated by extracting the center value of the shift. When subjected to lateral loads, the flexible force transmission layer 8 causes the central column to undergo slight torsion and rotation. The two piezoresistive bridges on the force application axis generate unequal deformation and resistance shifts due to the difference in force; at the same time, the two bridges perpendicular to this axis exhibit consistent morphological changes and equal resistance fluctuations. Based on the differential signal generated by the piezoresistive bridge along the force application axis, combined with the consistent signal in the vertical direction, the calculation and measurement of the three-dimensional resultant force (normal force and tangential force) are ultimately achieved. The dual-chip silicon-based MEMS sensors on the fingertip and fingertip have distinct functions: the fingertip is suitable for detecting the overall force during grasping, while the fingertip is better at sensing the mechanical information of fine pressing or localized contact. This distributed design enhances the comprehensive force perception of dexterous fingers.

[0047] Temperature detection principle: The silicon-based MEMS temperature and pressure sensing chip 10 incorporates a temperature-sensitive resistor strip (i.e., thermistor strip 13), whose resistance value adjusts according to thermal effects and changes in ambient temperature. When a finger touches an object, the resistor strip senses the temperature change in the contact area and generates a corresponding electrical signal. This signal is processed by the microcontroller, which outputs the temperature data of the contact point in real time. Dual-point detection of the fingertip and pad ensures spatial coverage and reliability of temperature information.

[0048] Proximity detection principle: The friction layer 5 of the flexible triboelectric sensing unit uses highly electronegative PTFE material and operates based on a single-electrode nano-tribosensitive mechanism. When an object approaches the finger surface, even without direct contact, the electrostatic coupling between the object and the PTFE causes a change in charge distribution, generating a weak voltage signal. The sensor's electrode layer captures this change, and after circuit amplification and filtering, generates a signal inversely proportional to the object's distance, achieving non-contact proximity detection.

[0049] Material type detection principle: Different materials have different electron cloud states, resulting in varying time-domain peak values ​​and morphologies of the triboelectric signals generated by the flexible triboelectric sensing unit. When the PTFE material used on the surface of a dexterous finger comes into contact with and separates from the surface of an object, it generates unique triboelectric signals. By analyzing these signal characteristics, the material type of the object can be distinguished, such as metal, plastic, or wood.

[0050] Roughness detection principle: The roughness of an object's surface affects the amplitude of the triboelectric signal of the flexible triboelectric sensing unit. The smaller the roughness, the larger the contact area, the more charge accumulates, and the higher the signal amplitude. By calibrating the relationship between signal amplitude and roughness, a dexterous finger can quantitatively detect the roughness of an object's surface.

[0051] Slip Detection Principle: Employing a dual-mode co-detection principle of triboelectric and piezoresistive signals, when an object slips during dexterous finger grasping, the change in contact force triggers a high-frequency vibration component in the triboelectric signal, manifesting as a sharp change in signal amplitude. This accurately captures the instantaneous occurrence of the slip event. Simultaneously, a silicon-based MEMS temperature and pressure sensing chip 10 detects pressure changes during the dexterous finger grasping process. During stable grasping, the resistance signal acquired by the silicon-based MEMS temperature and pressure sensing chip 10 exhibits relatively small fluctuations; however, when a slip event occurs, the change in friction causes significant fluctuations in the grasping force, resulting in a clear trend in the resistance signal. Under the combined effect of these two signal modes, when the dexterous finger contacts the object, the flexible triboelectric sensing unit determines the slip event initiation time window in real time through changes in surface charge. If slip is detected, the dexterous finger analyzes the synchronously acquired piezoresistive force signal to determine the slip state.

[0052] Circuit Detection Principle: The FPC integrated circuit 4 integrates the electrodes of the rigid sensing unit 7 and the flexible triboelectric sensing unit electrode 6. The circuit is built into the finger, requiring no external circuitry. The core circuit uses the MAX4617EUE switch chip. Pins X0-X7 are connected to S1-S8. Pins A, B, and C are controlled by RC0-RC2 of the PIC16F1825 microcontroller to select the input channel. The common output X is connected to a Wheatstone bridge circuit, converting resistance changes into voltage, which is output to RC3 and amplified to generate three-dimensional force information. The flexible triboelectric sensing unit electrode 6 is connected to the microcontroller RA2 to process the triboelectric signal when in contact with an object. The external communication interface 1 of the FPC integrated circuit 4 has only seven 0.5mm pitch pins (VCC, GND, RA0, RA1, RA3, RX, TX), supporting program programming and serial communication, achieving compact and efficient signal processing.

[0053] Furthermore, the multimodal tactile sensor of this invention performs excellently in practical applications of robotic dexterous fingers, covering multiple functions such as grasping, recognition, navigation, and fine manipulation. In scenarios involving grasping a water cup, when the dexterous finger contacts the surface of the cup, the sensor detects the three-dimensional force and temperature states in real time. When water is added to the cup, making it heavier, the dexterous finger identifies slippage trends through significant changes in triboelectric and piezoresistive signals, automatically adjusting the gripping force to ensure stable grasping. Simultaneously, the sensor can accurately identify the material of the water cup (such as metal, plastic, or ceramic) through the unique triboelectric signal pattern generated by PTFE upon contact, and distinguish surface roughness through signal amplitude analysis, making it suitable for sorting different types of water cups. In cluttered environments, the sensor utilizes proximity sensing to detect object distances through electrostatic field coupling, assisting the robotic dexterous hand in obstacle avoidance and navigation. Moreover, when performing fine operations such as assembly or surgical assistance, the sensor provides multimodal data including three-dimensional force, temperature, and material type, helping the robot achieve precise force control and environmental perception, significantly improving operational accuracy and adaptability.

[0054] This invention provides an integrated multimodal tactile sensing dexterous finger that simultaneously detects three-dimensional force, temperature, proximity, material type, roughness, and slippage. This surpasses traditional single-sensor systems, transforming the perception from "single signal sensing" to "understanding complex scenarios," thus improving the dexterous hand's operational accuracy and environmental adaptability. It further offers broad prospects for robots to more accurately understand their environment and human needs. Specifically, this invention can simultaneously detect three-dimensional force, temperature, proximity, material type, roughness, and slippage, overcoming the limitations of traditional single-sensor systems. The design employs a rigid-flexible coupled multimodal collaborative operation: a dual-chip silicon-based MEMS sensor at the fingertip and pad handles three-dimensional force and temperature detection, while a flexible triboelectric sensing unit on the finger surface, based on a PTFE single-electrode structure, innovatively achieves the perception of material type, roughness, and proximity. Furthermore, through a dual-modal co-detection method combining triboelectric and piezoresistive signals, the system can accurately identify the slippage state and its direction.

[0055] Furthermore, this invention is an integrated embedded sensing finger. Its core lies in completely embedding the sensor and its signal processing circuitry within the dexterous finger, connecting to the outside world only through a 7-pin FPC interface, achieving a compact and efficient system architecture. In terms of circuitry, the combination of the MAX4617EUE switching chip and the PIC16F1825 microcontroller supports efficient internal processing and output of multi-channel signals, ensuring the real-time nature and accuracy of the sensed data.

[0056] Example 2: This embodiment provides a robot, including the integrated multimodal tactile sensing dexterous finger provided in Embodiment 1.

[0057] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0058] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0059] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0060] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0061] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dexterous finger integrating multimodal tactile sensing, characterized in that, include: A flexible printed circuit includes a Wheatstone bridge circuit, a switching chip, a microcontroller, a rigid sensing unit, and flexible triboelectric sensing unit electrodes; the rigid sensing unit includes a sensing chip; the Wheatstone bridge circuit is connected to the switching chip, and the switching chip is connected to the microcontroller; the microcontroller is connected to the sensing chip and the flexible triboelectric sensing unit electrodes respectively. The dexterous finger housing includes a first housing and a second housing; the first housing and the second housing are connected to form a receiving cavity, and the flexible printed circuit is built into the receiving cavity; the first housing has a first notch, and the second housing has a second notch, and the first notch and the second notch form an opening; A flexible triboelectric sensing unit friction layer is disposed on the outer surfaces of the first and second outer shells; The friction layer of the flexible triboelectric sensing unit is connected to the rigid sensing unit and the electrode of the flexible triboelectric sensing unit through the opening.

2. The integrated multimodal tactile sensing dexterous finger according to claim 1, characterized in that, The rigid sensing unit further includes a flexible force transmission layer and a packaging shell; the flexible force transmission layer has a flexible force transmission cylinder on the side facing the packaging shell, and the surface of the packaging shell facing the flexible force transmission layer has a central through hole, through which the flexible force transmission cylinder passes and engages with the sensing chip.

3. The integrated multimodal tactile sensing dexterous finger according to claim 2, characterized in that, The side of the encapsulation shell away from the flexible force transmission layer is bottomless and connected to the flexible printed circuit board to form a cavity, in which the sensing chip is disposed.

4. The integrated multimodal tactile sensing dexterous finger according to claim 2, characterized in that, The flexible force transmission layer is connected to the friction layer of the flexible triboelectric sensing unit.

5. The integrated multimodal tactile sensing dexterous finger according to claim 1, characterized in that, The sensing chip includes a temperature-sensitive resistor strip, multiple varistor strips, multiple straight-bridge thin films, and multiple chip electrodes; the varistor strips are disposed above the straight-bridge thin films.

6. The integrated multimodal tactile sensing dexterous finger according to claim 1, characterized in that, The Wheatstone bridge circuit includes multiple decoupling capacitors, a first operational amplifier, and a second operational amplifier; the first operational amplifier is connected to the second operational amplifier; and the second operational amplifier is connected to at least one of the decoupling capacitors.

7. The integrated multimodal tactile sensing dexterous finger according to claim 1, characterized in that, The flexible printed circuit also includes an external communication interface, one end of which is connected to the microcontroller; the external communication interface is located on the outside of the dexterous finger shell.

8. The integrated multimodal tactile sensing dexterous finger according to claim 1, characterized in that, The dexterous finger shell has a connecting seat at one end for pin mounting.

9. The integrated multimodal tactile sensing dexterous finger according to claim 1, characterized in that, The friction layer of the flexible triboelectric sensing unit is a composite material of highly electronegative polytetrafluoroethylene powder and polydimethylsiloxane solution.

10. A robot, characterized in that, Including the integrated multimodal tactile sensing dexterous finger as described in any one of claims 1 to 9.

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