Pressure detection assembly for sensing normal force of fingernails of robot and bionic finger

Abstract

The utility model relates to a pressure detection assembly for sensing normal force of a nail of a robot. The pressure detection assembly comprises a tail end knuckle, an artificial nail and a processing module, the artificial nail is arranged at the tail end knuckle, the rigidity is more than 2 Morse, and the front edge of the nail extends outwards to form a knuckle fingertip to serve as a first stress area to be in physical contact with an external object; the tail end knuckle is provided with a first fulcrum acting on the artificial nail, and the artificial nail is supported by the first fulcrum to generate first rotating displacement under the action of normal force of the nail in the first stress area; at least one first pressure sensor having autonomous elastic recovery after being pressed is fixed on the travel path of the first rotational displacement for detecting the first one-dimensional force, the outer diameter dimension of the pressure sensor being configured to at most 99.8% of the maximum dimension of the nail; the processing module is coupled with the first pressure sensor and used for outputting normal force and / or torque acting on the first stress area according to the first one-dimensional force and the corresponding force arm.

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 normal force of a robot 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] The robot's terminal knuckle has only one degree of freedom in one direction. The terminal knuckle forms a finger bending action around its end joint, and the bending action is in the same direction as the nail 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. At the same time, the nail rotates. Torque is generally used to evaluate the interaction of the rotation of objects. Therefore, one of the purposes of the present utility model is to realize the perception of the normal force and torque of the robot nail.

[0008] To this end, a pressure detection assembly for sensing the normal force 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, the nail stiffness being set to be greater than 2 Mohs, and the leading edge of the nail extending outward from the knuckle tip as a first force-bearing area for physical contact with an external object; the terminal knuckle is provided with a first fulcrum acting on the artificial nail, and under the action of the nail normal force in the first force-bearing area, the artificial nail is supported by the first fulcrum to produce a first rotational displacement; at least one first pressure sensor capable of autonomous elastic recovery after being pressed is fixed on the path of the first rotational displacement 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 normal force and / or torque acting on the first force-bearing area based on the first unidimensional force and the corresponding lever arm. The first force-bearing area rotates about the first fulcrum due to the normal force. The first pressure sensor detects the first unidimensional force F2 generated by the nail rotation. After the structure is fixed, the power arm L1 and resistance arm L2 are known. The nail force F1 * lever arm L1 = the nail force F2 * lever arm L2 applied to the pressure sensor. The processing module outputs the normal force and / or torque acting on the first force-bearing area based on the first unidimensional force and the corresponding lever arm. The distal phalanx has only one degree of freedom in the bending direction. Using a force sensor on the rotational displacement and the nail anthropomorphically extending the nail, both the force magnitude and torque can be measured, meeting the requirements for measuring the nail normal force and torque.

[0009] As an improvement, the distance that the front edge of the nail extends outwards from the fingertip is 5%-50% of the nail body.

[0010] As another improvement, the power arm from the first force-bearing area to the first fulcrum and the resistance arm from the first pressure sensor to the first fulcrum are located on both sides or on the same side of the first fulcrum; or, the first pressure sensor is placed above and / or below the artificial nail.

[0011] As another improvement, the first fulcrum is supported on the upper surface between the base and leading edge of the nail. The bottom of the leading edge of the nail serves as the first force-bearing area, contacting an external object to generate a positive normal force. The first pressure sensor is fixed in the space below the base of the nail. Furthermore, the leading edge of the nail is tilted downward to form an offset from the extension direction. Furthermore, the upper surface of the artificial nail exposed at the terminal phalanx serves as the second force-bearing area for contact with external objects. At least one second pressure sensor, which has autonomous elastic recovery after being pressed, is arranged below the second force-bearing area of ​​the nail to support the nail. The second pressure sensor is used to detect a second unidimensional force. A processing module is coupled to the second pressure sensor to output a negative normal force acting on the second force-bearing area based on the second unidimensional force. Furthermore, the first and second pressure sensors are located together on the bottom surface of the artificial nail as a support. Furthermore, the terminal phalanx is provided with a slot to accommodate the base of the nail. The top surface of the inner sidewall of the slot and the first pressure sensor together form a clamp for the base of the nail. The upper edge of the slot serves as the first fulcrum.

[0012] 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.

[0013] As another improvement, the end of the front edge of the nail serves as the third force-bearing area in contact with an external object; the artificial nail slides along the fingertip direction and is connected to the terminal knuckle, and the artificial nail slides toward the knuckle under the force of the third force-bearing area, and at least one third pressure sensor with autonomous elastic recovery after being pressed is fixed on the sliding path to detect a third unidimensional force; the processing module is coupled to the third pressure sensor to output the force acting on the third force-bearing area based on the third unidimensional force.

[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] A bionic finger is also provided, comprising the above-mentioned pressure detection component. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The 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 The diagram shows the force applied to the nail when scratching or picking.

[0020] Figure 4a A first position setting method of the first fulcrum and the sensor is shown;

[0021] Figure 4b A second position setting method of the first fulcrum and the sensor is shown;

[0022] Figure 4c A third position setting method of the first fulcrum and the sensor is shown;

[0023] Figure 4d The fourth position setting method of the first fulcrum and the sensor is shown;

[0024] Figure 5a The structure of a capacitive one-dimensional force sensor is shown;

[0025] Figure 5b The structure of a capacitive three-dimensional force sensor is shown;

[0026] Figure 6 The nail's leading edge is shown tilted downward.

[0027] Figure 7a It shows the force on the upper surface of the nail when performing the elastic or pressing action;

[0028] Figure 7b shows the arrangement of the second pressure sensor;

[0029] Figure 8 The arrangement of the electrode array for sensing the second force-bearing area is shown;

[0030] Figure 9 The figure shows the force applied to the end of the front edge of the nail;

[0031] Figure 10a shows the state where the leading edge of the artificial nail is extended; and

[0032] Figure 10b The leading edge of the artificial nail is shown in a retracted state. DETAILED DESCRIPTION

[0033] 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.

[0034] Figure 1 The 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.

[0035] 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, and the front edge 21 of the nail extends outward from the fingertip as the first force-bearing area 21a to physically contact the external object. The first fulcrum 211 acting on the artificial nail is set on the fingertip, such as when performing scratching or picking actions. Figure 3 The first force-bearing area 21a acts on the contact object to generate a normal force F1, and the artificial nail 2 is supported by the first fulcrum 211 to generate a first rotational displacement 212. The first pressure sensor 213 with autonomous elastic recovery after pressing is fixed on the path of the first rotational displacement 212 to detect the first unidimensional force.

[0036] Figures 4a to 4d The settings of the force arm and the sensor 213 when the first fulcrum 211 is at different positions are given. Figure 4a 、 4c The power arm L1 from the first force-bearing area to the first fulcrum and the resistance arm L2 from the first pressure sensor to the first fulcrum are respectively located on both sides or on the same side of the first fulcrum 213, and the first pressure sensor 213 is placed above or below the artificial nail; Figure 4b 、 4dThe figure shows the position of the first fulcrum 211 and the setting of the lever arm when the normal force is from top to bottom in an elastic or pressing action. To meet the functional requirements of measuring both the downward and upward normal forces, the first pressure sensor 213 can have multiple locations on the upper and lower sides of the artificial nail.

[0037] 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 5b The 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 5bFor 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.

[0038] The first force-bearing area 21a rotates around the first fulcrum 211 under the influence of the normal force F1. After the power arm L1 is greater than the resistance arm L2 to amplify the force, the first pressure sensor 213 detects the first unidimensional force F2 generated by the nail rotation. Since L1 and L2 are known, the nail force F1 * lever arm L1 = the nail force F2 * lever arm L2 applied to the pressure sensor. The processing module outputs the normal force and / or torque acting on the first force-bearing area based on the first 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.

[0039] As an improved solution, the front edge of the nail extends outward at a distance of 5%-50% of the radial length of the nail body, forming a slight extension. When acting on an external object, the radial direction is limited by the fingertip, and the point of action between the object and the first force-bearing area is limited to an acceptable error range.

[0040] As another improvement, Figure 2 、 3 The first fulcrum 211 is supported on the upper surface between the base and the front edge of the nail. The bottom of the front edge of the nail acts as the first force-bearing area 21a, which contacts an external object and generates a positive normal force from bottom to top in the figure. The first pressure sensor 213 is fixed in the space below the base of the nail. When performing a scratching or picking action, the positive normal force causes a slight rotation of the nail to form a nail mechanics measurement. Figure 6 The example shows that the front edge of the nail is tilted downward to form an offset from the extension direction. By tilting downward, the nail uses the lower edge of the front edge to contact the external object, guiding the force application point on the first force area.

[0041] On this basis, Figure 7aThe force on the upper surface of the nail is shown. The upper surface of the artificial nail exposed at the end of the phalanx serves as the second force-bearing area 22a that contacts the external object. The second pressure sensor 221, which has autonomous elastic recovery after being pressed, is arranged below the second force-bearing area 22a of the nail to support the nail and detect the second unidimensional force. For example, when performing a spring or press action, the force forms a negative normal force from top to bottom. Figure 7b The second pressure sensor 221 is located directly below the second 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 second unidimensional force. The difference between the second unidimensional force and the negative normal force is small. The processing module is coupled to the second pressure sensor 221 and outputs the negative normal force acting on the second force-bearing area based on the second unidimensional force. Figure 7a The diagram illustrates the arrangement of the first pressure sensor 213 and the second pressure sensor 221 on the same side. In this case, the force sensors 213 and 221 are located together on the bottom surface of the artificial nail as a support, utilizing the space at the top of the fingertip at the bottom of the nail for storage. This facilitates a compact structure for the pressure detection assembly on the distal phalanx. More preferably, the distal phalanx is provided with a slot 300 to accommodate the root of the nail. The top surface of the inner sidewall of the slot 300 and the first pressure sensor 213 together form a clamp for the root of the nail. The upper edge of the slot 300 is reused as a first fulcrum. On the one hand, the inner sidewall of the slot and the first pressure sensor clamp enhance the overall stability of the structure. The top surface of the nail root forms an abutment with the sensor position to guide the nail's translation under negative normal force. On the other hand, the reuse of the upper edge of the slot as a first fulcrum further achieves a compact structure, facilitating the distal phalanx to simulate the size of a human finger.

[0042] 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 8 The arrangement of the electrode array for sensing the second force zone is given. Figure 8In the embodiment, the flexible FPC board 401 is attached to the bottom surface of the nail below the second force-bearing area, and the sensing electrodes 400 are distributed in a dot matrix on the FPC. The nail presses the second pressure sensor through the FPC. It should be understood that, if the design allows, the sensing electrode 400 is set on the surface of the second 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.

[0043] As another improvement, see Figure 8 、 Figure 9 The end of the front edge of the nail serves as the third force-bearing area 23a that contacts the external object. The artificial nail slides along the fingertip direction and is connected to the terminal knuckle. For example, when performing a poking action, the artificial nail slides toward the knuckle under the force of the third force-bearing area 23a. The third pressure sensor 231 with autonomous elastic recovery after pressing is fixed on the sliding path to detect the third unidimensional force.

[0044] There are many ways to implement the sliding of the artificial nail on the terminal knuckle. For example, see Figure 9 , a structure can be adopted in which the root of the nail is radially inserted into the knuckle groove, wherein the terminal knuckle is provided with a rectangular groove to accommodate the root of the nail, the notch of the groove faces the direction of the nail, the root of the nail is horizontally inserted into the groove, and there is a small gap to form a movable plug-in and pull-out. Furthermore, the side wall of the top surface of the artificial nail is in sliding contact with the inner wall of the terminal knuckle. To prevent the nail from sliding outward and detaching, a protrusion is formed on the inner wall of the terminal knuckle, and the hemispherical protrusion is embedded in the groove of the side wall of the top surface of the root of the nail. The groove is slightly larger than the protrusion, allowing the protrusion to slide radially in the groove, and cooperates to form a position limit for the sliding stroke. Furthermore, the protrusion can be strip-shaped or hemispherical, and its cross-section along the sliding direction forms an arc surface, which is conducive to reducing friction and does not hinder the rotation of the nail around the first fulcrum described below.

[0045] For example, when performing a poking action, the force is transmitted radially from left to right. Figure 9The third pressure sensor 232 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 third unidimensional force. The numerical difference between the unidimensional force and the nail force F3 is not much. The processing module is coupled to the third pressure sensor 232 and outputs the force acting on the first force area 23a according to the third unidimensional force.

[0046] 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.

[0047] The extension and retraction of animal nails has bionic significance. For applications requiring sharp nails, the extension and retraction of artificial nails can provide external protection under normal conditions. As another improved solution, the artificial nail includes a body 300, a nail front edge 301 movably and retractably arranged at the front end of the body 300, and a pressure detection component is provided with an actuator to drive the nail front edge 301 to extend or retract into the body 300. The actuation method can be electric or manual. As an example, Figure 10a 、 10b The diagram illustrates the two states of the leading edge of the artificial nail, extended and retracted. The leading edge 301 is spring-loaded to extend from the inner cavity of the body 300. The rear end of the leading edge 301 abuts against the inner cavity via a spring 302. The leading edge 301 is locked in place in both the extended and retracted positions by a push-on snap mechanism. Pressing the snap mechanism releases the lock, allowing the leading edge 301 to be pushed back into the body or ejected. Alternatively, a drive motor could be used to directly drive the extension and retraction of the leading edge 301 from the body.

[0048] 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 normal force of a robot 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, and the leading edge of the nail extends outward from the knuckle tip as the first force-bearing area to physically contact an external object; The distal finger joint is provided with a first fulcrum acting on the artificial nail. When a normal force of the nail is applied to the first force-bearing area, the artificial nail is supported by the first fulcrum to generate a first rotational displacement. At least one first pressure sensor capable of autonomous elastic recovery after being pressed is fixed on a path of the first rotational displacement 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 normal force and / or torque acting on the first force-bearing area based on the first unidimensional force and the corresponding lever arm.

2. The pressure detection assembly according to claim 1, 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.

3. The pressure detection assembly according to claim 1, characterized in that: The power arm from the first force-bearing area to the first fulcrum and the resistance arm from the first pressure sensor to the first fulcrum are located on both sides or on the same side of the first fulcrum; Alternatively, the first pressure sensor is placed above and / or below the artificial nail.

4. The pressure detection assembly according to claim 1, 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 first force-bearing area to contact an external object to generate a positive normal force. The first pressure sensor is fixed in the space below the root of the nail.

5. The pressure detection assembly according to claim 4, characterized in that: The leading edge of the nail is tilted downward, creating an offset from the direction of extension.

6. The pressure detection assembly according to claim 4, characterized in that: The artificial nail is exposed on the upper surface of the terminal knuckle as a second force-bearing area in contact with external objects; At least one second pressure sensor capable of autonomous elastic recovery after being pressed is arranged below the second force-bearing area of ​​the nail to support the nail, and the second pressure sensor is used to detect the second unidimensional force; The processing module is coupled to the second pressure sensor and is configured to output a negative normal force acting on the second force-bearing area according to the second unidimensional force.

7. The pressure detection assembly according to claim 6, characterized in that: The first pressure sensor and the second pressure sensor are located together on the bottom surface of the artificial nail as a support.

8. The pressure detection assembly according to claim 7, characterized in that: The terminal knuckle is provided with a slot to accommodate the base of the nail; The top surface of the inner side wall of the groove and the first pressure sensor together form a clamp for the root of the nail; The upper edge of the slotted notch is reused as the first fulcrum.

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 end of the front edge of the nail serves as the third force-bearing area in contact with external objects; The artificial nail is connected to the terminal knuckle in a sliding manner along the fingertip direction, and the artificial nail slides toward the knuckle under the force of the third force-bearing area. At least one third pressure sensor capable of autonomous elastic recovery after being pressed is fixed on the sliding path to detect the third unidimensional force; The processing module is coupled to the third pressure sensor and is configured to output the force acting on the third force-bearing area according to the third unidimensional force.

11. 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.

12. 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.

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

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