Pressure detection assembly for sensing stress of fingernail end part of robot and bionic finger

Abstract

The utility model relates to a pressure detection assembly for sensing the stress of the fingernail end part of a robot, which comprises a tail end knuckle, an artificial fingernail and a processing module, the artificial fingernail is installed on the tail end knuckle, the rigidity of the fingernail is 2 Morse or above, the front edge of the fingernail extends outwards to form a knuckle fingertip, and the end of the front edge of the fingernail serves as a first stress area to make physical contact with an external object; the artificial nail is connected to the tail end knuckle in a sliding mode in the fingertip direction, the artificial nail slides towards the knuckle under the stress of the first stress area, and at least one first pressure sensor with the automatic elastic recovery function after being pressed is fixed to a sliding path to be used for detecting first one-dimensional force; the outer diameter size of the pressure sensor is configured to be up to 99.8% of the maximum size of the fingernail; the processing module is coupled with the first pressure sensor and used for outputting the acting force borne by the first stress area according to the first single-dimensional force.

Description

Technical Field

[0001] The utility model relates to a household service robot, in particular to a pressure detection component and a bionic finger for sensing the force on the end of a robot's nail. Background Art

[0002] Home service robots are humanoid robotic devices capable of performing various service tasks in the home or similar environments. Market demand is currently growing rapidly. Compared to traditional robotic arms, which primarily serve industrial manufacturing, home service robots tend to provide daily life services in the home, acting as assistants or housekeepers.

[0003] Fingernails, as an essential component of human fingers, help people perform tasks such as scratching, picking, poking, and flicking. For home service robots, the robot's body is often coated with a flexible electronic skin to provide tactile input. Therefore, equipping the fingers with artificial nails will be more conducive to completing tasks such as scratching, picking, poking, and flicking. Furthermore, the fingertips formed by artificial nails combined with the flexible electronic skin are also beneficial for grasping small objects such as needles, screws for electronic products, and phone cards. When home service robots are equipped with artificial nails, measuring the force applied to the nails becomes a design challenge that needs to be solved. The robot system needs to be able to sense the force of scratching, snapping, and poking to avoid causing physical damage to the service recipient during home service tasks.

[0004] Six-axis force sensors, which simultaneously detect three force components and three torque components, are currently primarily used for six-axis force sensing in the shoulder, elbow, and / or wrist joints of industrial robotic arms or humanoid robots. These joints allow for three degrees of freedom of movement and provide ample space for six-axis force sensors, ranging in size from tens to thousands of millimeters. The size of six-axis force sensors varies by brand and model. For example, the American AT1 miniature six-axis force sensor measures 1714.5 mm, while the German Me-System three-dimensional force / six-axis force sensor has a housing size of 29 mm x 27 mm. Compared to measuring force and torque on the nail, using a six-axis force sensor to monitor nail mechanics is not suitable. One issue is the lack of space between the nail and the finger. More importantly, the cost is a concern. Currently, six-axis force sensors cost around 100,000 RMB each, making the high cost of these sensors difficult to gain market acceptance.

[0005] Patent document JP2023073764A discloses a robot system that recognizes the importance of setting nails for application services of an anthropomorphic robot and the task of measuring the force applied to the nails. The document proposes to use a six-dimensional force sensor to measure the force applied to the nails. Based on the above reasons, the six-dimensional force sensor is difficult to implement in terms of nail installation and cost control, so it has not yet been commercially promoted.

[0006] Based on this, how to measure the force on the nails of home service robots in a low-cost and feasible way has become an issue to be solved. Utility Model Content

[0007] For the poking action, the end of the nail is subjected to a radial force, and the magnitude of the force reacts on the contact object. Therefore, one of the purposes of the present invention is to realize the perception of the force on the end of the nail of the robot.

[0008] To this end, a pressure detection assembly for sensing force applied to the end of a robot's nail is provided, comprising a terminal knuckle, an artificial nail, and a processing module. The artificial nail is mounted on the terminal knuckle, with a stiffness of at least 2 Mohs. The leading edge of the nail extends outward from the knuckle tip, with the end of the leading edge of the nail serving as a first force-bearing zone for physical contact with an external object. The artificial nail is connected to the terminal knuckle in a sliding manner in the direction of the fingertip. Under force applied to the first force-bearing zone, the artificial nail slides toward the knuckle. At least one first pressure sensor capable of self-elastic recovery after being pressed is fixed to the sliding path to detect a first unidimensional force. The outer diameter of the pressure sensor is configured to be at most 99.8% of the maximum dimension of the nail. The processing module is coupled to the first pressure sensor and is configured to output the force applied to the first force-bearing zone based on the first unidimensional force. For example, during a poking action, force is transmitted radially along the nail. The first pressure sensor is located in the positive direction of the sliding path. The elasticity of the pressure sensor allows the nail to slide to a certain extent while detecting the first unidimensional force. The difference between the first unidimensional force and the force applied to the nail is not significant. The processing module outputs the force applied to the first force-bearing zone based on the first unidimensional force.

[0009] As an improvement, the protrusion on the inner wall of the terminal knuckle cooperates with the groove on the side wall of the artificial nail to form a position limit for the sliding stroke.

[0010] As another improvement, the bottom and / or top of the leading edge of the nail serves as the second force-bearing area in contact with external objects; the terminal knuckle is provided with a first fulcrum acting on the artificial nail, and when the second force-bearing area is acted upon by the normal force of the nail, the artificial nail is supported by the first fulcrum to produce a first rotational displacement, and at least one second pressure sensor with autonomous elastic recovery after being pressed is fixed on the path of the first rotational displacement to detect a second unidimensional force; the processing module is coupled to the second pressure sensor to output the normal force and / or torque acting on the second force-bearing area based on the second unidimensional force and the corresponding lever arm.

[0011] Furthermore, the distance from the front edge of the nail extending outward to the fingertip is 5%-50% of the length of the nail body.

[0012] Furthermore, the first fulcrum is supported on the upper surface between the root and the front edge of the nail, and the bottom of the front edge of the nail serves as the second force-bearing area to contact an external object to generate a positive normal force. The second pressure sensor is fixed in the space below the root of the nail. Furthermore, the inner wall of the terminal phalanx and the second pressure sensor together form a clamp for the artificial nail, and there is a gap between the artificial nail and the inner wall of the terminal phalanx and / or the second pressure sensor for the artificial nail to slide. Furthermore, the front edge of the nail is tilted downward to form an offset from the extension direction. Furthermore, the artificial nail is exposed on the upper surface of the terminal phalanx as a third force-bearing area in contact with an external object; at least one third pressure sensor with autonomous elastic recovery after being pressed is arranged below the third force-bearing area of ​​the nail to support the nail, and the third pressure sensor is used to detect a third unidimensional force; the processing module is coupled to the third pressure sensor and is used to output the negative normal force acting on the third force-bearing area based on the third unidimensional force.

[0013] As another improvement, the pressure detection component includes a capacitance-to-digital conversion circuit and multiple sensing electrodes; the multiple sensing electrodes form an electrode matrix for sensing the approach of an object to a force-bearing area and / or the contact of an object on the force-bearing area; the capacitance-to-digital conversion circuit couples the individual sensing electrodes in the electrode matrix to obtain self-capacitance and / or mutual capacitance; the processing module is coupled to the capacitance-to-digital conversion circuit for outputting an electrical signal sensing the approach of an external object and / or outputting the position of the force point and / or the force area acting on the force-bearing area based on the self-capacitance and / or mutual capacitance.

[0014] As another improvement, the artificial nail includes a body, and the leading edge of the nail is movably and telescopically arranged at the front end of the body; the pressure detection component is provided with an actuating device for driving the leading edge of the nail to extend out of or retract into the body.

[0015] As another improvement, the pressure sensor is configured as a one-dimensional force sensor; or, the pressure sensor includes a flexible body, an upper electrode is arranged inside the flexible body, the upper electrode is a curved elastic electrode, one or more lower electrodes are arranged below the upper electrode, an insulating layer is provided on the bottom surface of the upper electrode and / or the top surface of the lower electrode, the projection of the upper electrode relative to the lower electrode covers at least part of the area of ​​the lower electrode, the flexible body is deformed by external force, driving the upper electrode to change the indirect contact area with the lower electrode, the pressure detection component includes a capacitance-to-digital conversion circuit, the capacitance-to-digital conversion circuit couples each upper electrode and the lower electrode, and the processing module is coupled to the capacitance-to-digital conversion circuit.

[0016] Also provided is a bionic finger comprising the pressure detection component. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1The structural composition of the terminal knuckle of the bionic finger is shown;

[0018] Figure 2 The internal structure of the terminal knuckle of the bionic finger is shown;

[0019] Figure 3 shows the arrangement of the first pressure sensor;

[0020] Figure 4 The figure shows the force applied to the nail when performing the poking action;

[0021] Figure 5a The structure of a capacitive unidimensional force sensor is shown;

[0022] Figure 5b The structure of a capacitive three-dimensional force sensor is shown;

[0023] Figure 6 It shows the force applied to the nails when performing actions such as scratching and picking;

[0024] Figure 7a A first position setting method of the first fulcrum and the sensor is shown;

[0025] Figure 7b A second position setting method of the first fulcrum and the sensor is shown;

[0026] Figure 7c A third position setting method of the first fulcrum and the sensor is shown;

[0027] Figure 7d The fourth position setting method of the first fulcrum and the sensor is shown;

[0028] Figure 8 The nail's leading edge is shown tilted downward.

[0029] Figure 9a It shows the force on the upper surface of the nail when performing the elastic or pressing action;

[0030] Figure 9b shows the arrangement of the third pressure sensor; and

[0031] Figure 10 The arrangement of the electrode array for sensing the third force-bearing area is shown. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] Figure 1The structure of the bionic finger's distal knuckle is shown. The knuckle is anthropomorphic, with its outer surface imitating human skin and coated with a flexible electronic skin for tactile perception. An artificial nail 2 is attached to the tip of the distal knuckle 1. The knuckle houses a processing module, circuitry, and other components, forming an independent finger module. The distal knuckle 1, artificial nail 2, and processing module form a pressure detection assembly that senses the force exerted by the robot's nail.

[0034] Human nails are relatively flexible when connected to flesh and blood tissues. In order to provide more uses beyond human nails and reduce the error of force measurement, see Figure 2 The artificial nail 2 has a stiffness of 2 Mohs or more. The front edge 21 of the nail extends outward from the fingertip. The end of the front edge 21 of the nail serves as the first force-bearing area 21a to physically contact an external object. The artificial nail 2 is connected to the end of the fingertip by sliding along the fingertip. For example, when performing a poking action, the artificial nail slides toward the fingertip under the force of the first force-bearing area 21a. Figure 3 At least one first pressure sensor 212 capable of autonomous elastic recovery after being pressed is fixed on the sliding path to detect the first unidimensional force F1'.

[0035] There are many ways to implement the sliding of the artificial nail 2 on the distal knuckle 1. As an example, Figure 4 The structure of the fingernail root radially inserted into the phalanx groove is shown, wherein the terminal phalanx 1 is provided with a rectangular groove 300 to accommodate the nail root. The notch of the groove 300 faces the nail, and the nail root is horizontally inserted into the groove 300 with a small gap to allow for movable insertion and removal. Furthermore, the top side wall of the artificial nail 2 is in sliding contact with the inner wall of the terminal phalanx 1. To prevent the nail from sliding outward, a protrusion 11 is formed on the inner wall of the terminal phalanx 1. The hemispherical protrusion 11 is embedded in the groove 213 on the top side wall of the nail root. The groove 213 is slightly larger than the protrusion 11, allowing the protrusion 11 to slide radially within the groove and cooperate to form a position limit for the sliding stroke. Furthermore, the protrusion 11 can be strip-shaped or hemispherical, and its cross-section along the sliding direction forms an arc surface, which helps reduce friction while not hindering the rotation of the nail around the first fulcrum described below.

[0036] The outer diameter of the pressure sensor is configured to be at most 99.8% of the maximum size of the nail to meet the requirements of both the accommodation installation and force detection between the robot's end knuckle and the artificial nail. The implementation of a pressure sensor that meets this size can be diverse. One example is functional tailoring, which uses a single-dimensional force sensor to meet the size requirements. A single-dimensional force sensor, such as a piezoelectric force sensor, a parallel plate capacitive force sensor, etc., only measures the force in one direction, and the size can be made small enough while meeting cost control. Another embodiment can be to use Figure 5a 、 Figure 5bThe force sensor structure shown in the figure includes a flexible body 500, which is convex upward to increase the force. An upper electrode 501 is provided inside the flexible body 500. The upper electrode 501 is a curved elastic electrode that convexly extends downward from the inside of the flexible body 500 to form a shape similar to a sphere or an ellipse. A material such as a Figure 5a As shown, a lower electrode 502 is formed to detect normal unidirectional force, or a lower electrode 502 is provided. Figure 5b The plurality of lower electrodes 502, in addition to normal force measurement, allow tangential force measurement without increasing the volume, optimally, such as Figure 5b Four electrodes 5021 , 5022 , 5023 , and 5024 are provided to achieve three-dimensional force detection. Figure 5a 、 Figure 5b An insulating layer is provided on the bottom surface of the upper electrode 501 and / or the top surface of the lower electrode 502. The insulating layer acts as a dielectric material between the upper and lower electrodes, providing an increase in dielectric constant of more than one order of magnitude compared to air. The projection of the upper electrode 501 relative to the lower electrode 502 covers at least part of the area of ​​the lower electrode 502. The deformation of the flexible body 500 by the external force drives the upper electrode 501 to change the indirect contact area with the lower electrode 502. For example, pressing downwards will increase the contact area, and removing the external force will reduce the contact area under the elastic recovery of the flexible body. Due to the small spacing (the upper and lower electrodes are in contact through the insulating layer), the large dielectric (the material of the insulating layer itself), and the large change in contact area (the change in area from point contact to surface contact is huge), the force detection sensitivity of the sensor is very high, comparable to the resolution of a human fingertip, and at the same time, the volume can be relatively small, meeting the accommodation and installation requirements between the terminal knuckle and the artificial nail. The pressure detection component is provided with a capacitance-to-digital conversion circuit (CDC) implementation Figure 5a 、 Figure 5b For the acquisition of capacitance, CDCs such as DAI7142 and ADI7147 use a Δ-Σ modulation method to directly convert the measured capacitance value into a digital value by repeatedly charging and discharging the measured capacitance and comparing it with a reference capacitance (see: US Patent Number: 5,134,401). This can increase the measurement sensitivity of the capacitance to the 1ff level, and easily meet the measurement system's requirements for capacitance measurement sensitivity. At the same time, it also has the characteristic of being immune to stray capacitance. In particular, the design of these chips has multiple channels. When connected, the capacitance-to-digital conversion circuit couples each upper electrode and the lower electrode, and the processing module couples the capacitance-to-digital conversion circuit.

[0037] For example, when performing a poking action, the force is transmitted radially from left to right. Figure 4The first pressure sensor 212 shown is located in the positive direction of the sliding path. The elasticity of the pressure sensor allows the nail to slide to a certain extent while detecting the first unidimensional force F1'. The numerical difference between the first unidimensional force F1' and the force F1 applied to the nail is not much. The processing module is coupled to the first pressure sensor 212 and outputs the force applied to the first force area 21a based on F1'.

[0038] The robot's distal knuckle has only one degree of freedom in one direction. The distal knuckle bends around its end joint, and the bending motion is in the same direction as the nail's normal. For actions such as scratching and picking, the nail is subjected to a force along the normal direction, and the magnitude of the force reacts on the contact object, while the nail rotates. Torque is generally used to evaluate the interaction of the rotation of the object. Based on this, as an improvement, Figure 6 The figure shows the force applied to the nail when scratching or picking. The bottom and / or top of the front edge of the nail serves as the second force-bearing area 22a in contact with the external object. The terminal knuckle is provided with a first fulcrum 221 acting on the artificial nail. For example, when scratching or picking is performed, under the action of the normal force of the nail in the second force-bearing area 22a, the artificial nail is supported by the first fulcrum 221 to generate a first rotational displacement 222. At least one second pressure sensor 223 with autonomous elastic recovery after being pressed is fixed on the travel path of the first rotational displacement 222 to detect the second unidimensional force.

[0039] Figures 7a to 7d The settings of the force arm and the sensor 223 when the first fulcrum 221 is at different positions are given. Figure 7a 、 7c The power arm L1 from the second force-bearing area to the first fulcrum and the resistance arm L2 from the second pressure sensor to the first fulcrum are respectively located on both sides or on the same side of the first fulcrum 221, and the second pressure sensor 223 is placed above or below the artificial nail; Figure 7b 、 7d It shows the position of the first fulcrum 221 and the setting of the lever arm when the normal force is from top to bottom in an elastic or pressing action; in order to meet the functional requirements of measuring both the downward normal force and the upward normal force, the second pressure sensor 223 can have multiple locations on the upper and lower sides of the artificial nail.

[0040] The second force-bearing area 22a rotates around the first fulcrum 221 due to the normal force F2. After the power arm L1 is greater than the resistance arm L2, the force is amplified. The second pressure sensor 223 detects the second unidimensional force F3 generated by the nail rotation. Since L1 and L2 are known, the nail force F2 * lever arm L1 = the nail force F3 * lever arm L2 applied to the pressure sensor. The processing module outputs the normal force and / or torque acting on the second force-bearing area based on the second unidimensional force and the corresponding lever arm. Since the distal phalanx has only one degree of freedom in the bending direction, a force sensor on the rotational displacement can be used in conjunction with the nail to simulate the extension of the nail to achieve both force and torque measurements, meeting the nail normal force and torque measurement requirements.

[0041] further, Figure 4 The first support point 221 is supported on the upper surface between the root and the front edge of the nail, and the bottom of the front edge of the nail serves as the second force-bearing area 22a to contact external objects to generate Figure 6 The second pressure sensor 223 is fixed in the space below the root of the nail to measure the positive normal force from bottom to top. When performing a scratching or picking action, the positive normal force causes a slight rotation of the nail to form a nail mechanical measurement. Furthermore, the root of the nail is radially inserted into the knuckle groove 300, and the inner wall of the terminal knuckle and the second pressure sensor 223 together form a clamp for the artificial nail. There is a gap between the artificial nail and the inner wall of the terminal knuckle and / or the second pressure sensor for the artificial nail to slide, allowing it to slide. The inner side wall of the groove and the second pressure sensor clamp enhance the overall stability of the structure, and the top surface of the nail root forms an abutment with the sensor position to guide the nail to translate under the negative normal force.

[0042] Figure 8 The example shows a nail with its leading edge tilted downward, creating an offset from the extension direction. This downward tilt allows the lower edge of the leading edge of the nail to contact an external object, guiding the force application point to the second force-bearing zone. The leading edge of the nail extends slightly outward from the fingertip by 5%-50% of the radial length of the nail body. When impacting an external object, the fingertip limits the radial position, limiting the point of impact between the object and the second force-bearing zone to within an acceptable error range.

[0043] On this basis, Figure 9a The force on the nail surface is shown in the figure. The upper surface of the artificial nail exposed at the end of the phalanx serves as the third force-bearing area 23a that contacts the external object. The second pressure sensor 231, which has autonomous elastic recovery after being pressed, is arranged below the third force-bearing area 23a of the nail to support the nail and detect the third unidimensional force. For example, when performing a spring or press action, the force forms a negative normal force from top to bottom. Figure 9bThe third pressure sensor 221 is located directly below the third force-bearing area 22a. The elasticity of the pressure sensor allows the nail to move downward to a certain extent under the negative normal force while detecting the third unidimensional force. The difference between the third unidimensional force and the negative normal force is small. The processing module is coupled to the third pressure sensor 231 and outputs the negative normal force acting on the third force-bearing area based on the third unidimensional force. Figure 9a The diagram illustrates the co-location of the second and third pressure sensors 223 and 231. In this case, force sensors 223 and 231 are co-located on the bottom surface of the artificial nail, serving as a support. This utilizes the space above the fingertip at the base of the nail for storage, facilitating a compact structure for the pressure sensing assembly on the distal phalanx. More preferably, the upper edge of the slot 300 serves as the first fulcrum, further achieving a compact structure and helping the distal phalanx simulate the size of a human finger.

[0044] The utility model decomposes and senses the force applied to the nail based on the consideration that the terminal knuckle has only one degree of freedom of rotation in one direction. It comprehensively evaluates the force condition of the nail through the dimensions of positive normal force and torque, negative normal force, and radial force at the end of the nail, thereby realizing the force perception of the nail. At the same time, the force perception task in three directions is apportioned to three sensors at different positions, which is conducive to saving sensor space and cost, and completing the bionic task of simulating the size of human fingers with the knuckles.

[0045] As another improvement, the pressure detection assembly is provided with a plurality of sensing electrodes 400 to form a multi-row and multi-column electrode array, and the electrode array is used to sense the object's approach to the force-bearing area and / or the contact on the force-bearing area. The electrode array can be arranged on the surface and / or the space below the force-bearing area to form proximity sensing and / or contact sensing including but not limited to the first force-bearing area, the second force-bearing area and / or the third force-bearing area. As an example, Figure 10 The arrangement of the electrode array for sensing the third force zone is given. Figure 10In the embodiment, the flexible FPC board 401 is attached to the bottom surface of the nail below the third force-bearing area, and the sensing electrodes 400 are distributed in a dot matrix on the FPC. The nail presses the third pressure sensor through the FPC. It should be understood that, if the design allows, the sensing electrodes 400 can be arranged on the surface of the third force-bearing area using a transparent conductive material to achieve basically the same purpose. The capacitance-to-digital conversion circuit couples each sensing electrode in the electrode dot matrix to obtain self-capacitance and / or mutual capacitance. The processing module is coupled to the capacitance-to-digital conversion circuit to output an electrical signal that senses the approach of an external object and / or outputs the position of the force point and / or the force area acting on the force-bearing area based on the self-capacitance and / or mutual capacitance. When an external object approaches but does not touch the force-bearing area, the approach of a conductive or non-conductive external object changes the dielectric constant in the mutual capacitance electric field, causing a change in mutual capacitance, or the approach of a conductive object couples with the electrode, causing a change in self-capacitance. The approach of the object is sensed by changes in self-capacitance and / or mutual capacitance. When an object contacts the force-bearing area, the significant difference in mutual capacitance and / or self-capacitance between the electrodes in the contact area and the electrodes in the non-contact area on the dot matrix is ​​used to sense the contact boundary and position of the object, and output the force point and / or force area.

[0046] The extension and retraction of animal nails has bionic significance. For applications that require sharp nails, the extension and retraction of artificial nails has an external protective effect under normal conditions. As another improvement scheme, the artificial nail includes a main body, the front edge of the nail is movably and retractably arranged at the front end of the main body, and the pressure detection component is provided with an actuator that drives the front edge of the nail to extend or retract into the main body. The actuation method can be electric or manual. As an example, the manual scheme can be set to have the front edge of the nail extended from the inner cavity of the main body by a spring, and the rear end of the front edge abuts the inner cavity through a spring. The front edge is locked by a press-type snap structure when it moves to the first extended position and the second retracted position. The press-type snap structure releases the locked state, allowing the front edge to be pressed back into the main body or the front edge to pop out.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit the scope of protection of the utility model. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in this field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the utility model.

Claims

1. A pressure detection component for sensing the force applied to the end of a robot's nail, characterized by: Including terminal knuckle, artificial nail, and processing module; The artificial nail is mounted on the distal knuckle, the nail stiffness is set to be above 2 Mohs, the leading edge of the nail extends outward from the knuckle tip, and the end of the leading edge of the nail serves as a first force-bearing area to physically contact an external object; The artificial nail is slidably connected to the terminal knuckle along the fingertip direction, and the artificial nail slides toward the knuckle when a force is applied to the first force-bearing area. At least one first pressure sensor capable of autonomous elastic recovery after being pressed is fixed on the sliding path to detect a first unidimensional force, and the outer diameter of the pressure sensor is configured to be at most 99.8% of the maximum dimension of the nail. The processing module is coupled to the first pressure sensor and is configured to output the force acting on the first force-bearing area according to the first unidimensional force.

2. The pressure detection assembly according to claim 1, characterized in that: The protrusion on the inner wall of the terminal finger joint cooperates with the groove on the side wall of the artificial nail to form a position limit for the sliding stroke.

3. The pressure detection assembly according to claim 1, characterized in that: The bottom and / or top of the leading edge of the nail serves as the second force-bearing area that contacts external objects; The distal finger joint is provided with a first fulcrum acting on the artificial nail. When the second force-bearing area is subjected to the normal force of the nail, the artificial nail is supported by the first fulcrum and generates a first rotational displacement. At least one second pressure sensor capable of autonomous elastic recovery after being pressed is fixed on the path of the first rotational displacement to detect a second unidimensional force. The processing module is coupled to the second pressure sensor and is used to output the normal force and / or torque acting on the second force-bearing area based on the second unidimensional force and the corresponding lever arm.

4. The pressure detection assembly according to claim 3, characterized in that: The distance from the front edge of the nail to the fingertip is 5%-50% of the length of the nail body.

5. The pressure detection assembly according to claim 3, characterized in that: The first fulcrum is supported on the upper surface between the root and the front edge of the nail, the bottom of the front edge of the nail serves as the second force-bearing area to contact an external object to generate a positive normal force, and the second pressure sensor is fixed in the space below the root of the nail.

6. The pressure detection assembly according to claim 5, characterized in that: The inner wall of the terminal phalanx and the second pressure sensor together form a clamp for the artificial nail, and a gap is provided between the artificial nail and the inner wall of the terminal phalanx and / or the second pressure sensor for the artificial nail to slide.

7. The pressure detection assembly according to claim 5, characterized in that: The leading edge of the nail is tilted downward, creating an offset from the direction of extension.

8. The pressure detection assembly according to claim 5, characterized in that: The artificial nail is exposed on the upper surface of the terminal knuckle as a third force-bearing area in contact with external objects; At least one third pressure sensor capable of autonomous elastic recovery after being pressed is arranged below the third force-bearing area of ​​the nail to support the nail, and the third pressure sensor is used to detect a third unidimensional force; The processing module is coupled to the third pressure sensor and is configured to output a negative normal force acting on the third force-bearing area according to the third unidimensional force.

9. The pressure detection assembly according to claim 1, characterized in that: The pressure detection component includes a capacitance-to-digital conversion circuit and a plurality of sensing electrodes; A plurality of sensing electrodes form an electrode array for sensing an object approaching the force-bearing area and / or contacting the force-bearing area; The capacitance-to-digital conversion circuit couples each sensing electrode in the electrode array to obtain self-capacitance and / or mutual capacitance; The processing module is coupled with a capacitance-to-digital conversion circuit, and is used to output an electrical signal for sensing the approach of an external object and / or output the position of a force point and / or a force area acting on the force zone based on self-capacitance and / or mutual capacitance.

10. The pressure detection assembly according to claim 1, characterized in that: The artificial nail comprises a body, and the front edge of the nail is movably and telescopically arranged at the front end of the body; The pressure detection component is provided with an actuating device for driving the leading edge of the nail to extend out of or retract into the body.

11. The pressure detection assembly according to claim 1, characterized in that: The pressure sensor is configured as a single-dimensional force sensor; Alternatively, the pressure sensor includes a flexible body, an upper electrode is arranged inside the flexible body, the upper electrode is a curved elastic electrode, one or more lower electrodes are arranged below the upper electrode, an insulating layer is provided on the bottom surface of the upper electrode and / or the top surface of the lower electrode, the projection of the upper electrode relative to the lower electrode covers at least part of the area of ​​the lower electrode, the flexible body is deformed by external force, and the upper electrode changes its indirect contact area with the lower electrode, the pressure detection component includes a capacitance-to-digital conversion circuit, the capacitance-to-digital conversion circuit couples each upper electrode and the lower electrode, and the processing module is coupled to the capacitance-to-digital conversion circuit.

12. A bionic finger, characterized in that: The invention comprises the pressure detection component according to any one of claims 1 to 11.

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