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

Abstract

The invention relates to a pressure detection assembly for sensing the stress of the nail end part of a robot, and a bionic finger. The pressure detection assembly comprises a tail end knuckle, an artificial nail 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 dimension of the pressure sensor is configured to be up to 100% of the maximum dimension of the nail; 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 invention 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 anthropomorphic robot devices that can perform various service tasks in home environments or similar environments. The current market demand is increasingly fierce. Compared with traditional robotic arms that serve industrial manufacturing, home service robots tend to provide daily life services in home environments as life assistants or housekeepers.

[0003] Fingernails are an important part of human fingers, helping people complete various tasks such as scratching, picking, poking, and flicking. For home service robots, the surface of the robot body is usually wrapped with flexible electronic skin to provide tactile perception input. Therefore, equipping fingers with artificial nails will be more conducive to completing tasks such as scratching, picking, poking, and flicking. In addition, the fingertips formed by artificial nails and flexible electronic skin are also conducive to grasping tiny objects, such as needles, screws of electronic products, phone cards, etc. After the fingers of the home service robot are equipped with artificial nails, how to complete the force measurement of the nails becomes a design problem to be solved. The machine system needs to be able to sense the force of scratching, flicking fingers, and poking things, so as to avoid causing force damage to the service object during home service tasks.

[0004] As a force sensor that detects three force components and three torque components at the same time, the six-dimensional force sensor is currently mainly used in the shoulder joint, elbow joint and / or wrist joint of industrial manipulators or humanoid robots to complete six-dimensional force perception. These joints allow three degrees of freedom of movement in three directions and can provide a large enough space to place six-dimensional force sensors ranging from tens to thousands of millimeters. The size of the six-dimensional force sensor varies depending on the brand and model. For example, the size of the American AT I micro six-dimensional force sensor is Φ1714.5 (mm), and the shell size of the German Me-System three-dimensional force / six-dimensional force sensor is 29mmX27mm. Compared with the measurement of the force and torque of the nail, it is not appropriate to use a six-dimensional force sensor to detect the mechanics of the nail. One aspect of the problem is that there is not enough space between the nail and the finger. The more important aspect is the cost issue. At present, the purchase price of the six-dimensional force sensor is basically around RMB 100,000 per unit. The high sensor cost makes the design difficult to be accepted by the market.

[0005] Patent document JP2023073764A discloses a robot system, noting the importance of setting nails for application services of anthropomorphic robots and the task of measuring the force on the nails. The document proposes to use a six-dimensional force sensor to measure the force on 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 been commercially promoted yet.

[0006] Based on this, how to measure the force on the nails of a household service robot in a low-cost and feasible manner has become an issue to be solved. Summary of the invention

[0007] For the poking action, the end of the nail is subjected to a radial force, and the magnitude of the force reacts against 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 component for sensing the force on the end of a robot nail is provided, comprising a terminal knuckle, an artificial nail, and a processing module; the artificial nail is installed on the terminal knuckle, the stiffness of the nail is set to be above 2 Mohs, the front edge of the nail extends outward from the knuckle fingertip, and the end of the front edge of the nail is used as a first force-bearing area to physically contact with an external object; the artificial nail is connected to the terminal knuckle by sliding along the fingertip direction, the artificial nail slides toward the knuckle under the force of the first force-bearing area, at least one first pressure sensor with autonomous elastic recovery after pressing is fixed on the sliding path to detect the first unidimensional force, and the outer diameter size of the pressure sensor is configured to be at most 100% of the maximum size of the nail; the processing module is coupled with the first pressure sensor to output the force on the first force-bearing area according to the first unidimensional force. For example, when a poking action is implemented, the force is transmitted along the radial direction of 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 numerical difference between the first unidimensional force and the force on the nail is not large, and the processing module outputs the force on the first force-bearing area according to 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 locking limit for the sliding stroke.

[0010] As another improvement, the bottom and / or top of the front edge of the nail serves as the second force-bearing area in contact with an external object; 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 to the fingertip is 5%-50% of the nail body.

[0012] Further, 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 the external object to generate a positive normal force, and the second pressure sensor is fixed in the space below the root of the nail. Further, the inner wall of the terminal knuckle 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 knuckle and / or the second pressure sensor for the artificial nail to slide. Further, the front edge of the nail is tilted downward to form an offset from the extension direction. Further, the artificial nail is exposed on the upper surface of the terminal knuckle as a third force-bearing area in contact with an external object; at least one third pressure sensor with autonomous elastic recovery after pressing 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 according to 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 dot 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 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 for outputting an electrical signal that senses the approach of an external object and / or outputting the position of a force point and / or a 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 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 actuator for driving the front edge of the nail to extend out 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 arranged 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 at least covers a 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 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 the poking action is performed;

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

[0022] Figure 5b The capacitive three-dimensional force sensor structure 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 A fourth position setting method of the first fulcrum and the sensor is shown;

[0028] Figure 8 The structure of the leading edge of the nail tilting downward is shown;

[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 a third pressure sensor; and

[0031] Fig.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 in conjunction with the accompanying drawings in the embodiments of the present invention.

[0033] Figure 1The structure of the end knuckle of the bionic finger is shown. The knuckle is anthropomorphic, and the outer surface imitates human skin and is covered with flexible electronic skin to achieve tactile perception. Artificial nail 2 is installed on the top of the fingertip of the end knuckle 1. The processing module, circuit and other devices are placed inside the knuckle to form an independent finger module. The end knuckle 1, artificial nail 2 and processing module constitute a pressure detection component that senses the robot's nail force.

[0034] Human nails are relatively flexible when connected to flesh and blood tissue. 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 more than 2 Mohs, and the front edge 21 of the nail extends outward from the fingertip of the knuckle. The end of the front edge 21 of the nail serves as the first force-bearing area 21a to physically contact with an external object. The artificial nail 2 is connected to the end knuckle 1 by sliding along the fingertip direction. For example, when performing a poking action, the artificial nail slides toward the knuckle under the force of the first force-bearing area 21a. Figure 3 At least one first pressure sensor 212 having autonomous elastic recovery after being pressed is fixed on the sliding path to detect the first unidimensional force F1'.

[0035] The artificial nail 2 can slide on the distal knuckle 1 in various ways. As an example, Figure 4 The structure of the nail root radially inserted into the knuckle groove is shown, wherein the terminal knuckle 1 is provided with a rectangular groove 300 to accommodate the nail root, the notch of the groove 300 faces the nail direction, the nail root is horizontally inserted into the groove 300, and there is a small gap to form a movable plug-in. Further, the side wall of the top surface of the artificial nail 2 is in sliding contact with the inner wall of the terminal knuckle 1. To prevent the nail from sliding outward, a protrusion 11 is formed on the inner wall of the terminal knuckle 1. The hemispherical protrusion 11 is embedded in the groove 213 of the top surface side wall of the nail root. The groove 213 is slightly larger than the protrusion 11, allowing the protrusion 11 to slide radially in the groove, and cooperate to form a position limit for the sliding stroke. Further, the protrusion 11 can be a strip or a hemisphere, 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.

[0036] The outer diameter of the pressure sensor is configured to be at most 100% 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 allows it to be small enough while meeting cost control. Another embodiment can be to use Figure 5a , Figure 5bThe force sensor structure shown in the figure comprises a flexible body 500, which is convex upward to increase the force. An upper electrode 501 is arranged inside the flexible body 500. The upper electrode 501 is a curved elastic electrode, which is convex downward from the inside of the flexible body 500 to form a shape similar to a sphere or an ellipse. A Figure 5a A lower electrode 502 is shown, forming a normal unidirectional force detection, or is provided with a 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 middle 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 external force drives the upper electrode 501 to change the indirect contact area with the lower electrode 502. For example, pressing downwards manifests as an increase in the contact surface, and removing the external force manifests as a decrease in the contact surface 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), large dielectric (the material of the insulating layer itself), and large change in contact area (the change in the area from point contact to surface contact is huge), the force detection sensitivity of the sensor is very high, which can be comparable to the resolution of human fingertips. At the same time, the volume can be relatively small to meet 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 In the acquisition of medium capacitance, CDC, such as DAI7142 and ADI7147, adopts Δ-∑ modulation method to charge and discharge the measured capacitance multiple times and compare it with the reference capacitance (see: US Patent Number: 5,134,401) to directly convert the measured capacitance value into a digital value, which can improve the measurement sensitivity of the capacitance to 1ff level, and easily meet the measurement system's requirements for capacitance measurement sensitivity. At the same time, it also has the characteristics of immunity 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 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 nail force F1 is not large. The processing module is coupled to the first pressure sensor 212 and outputs the force acting on the first force area 21a according to F1'.

[0038] The robot's end knuckle has only one degree of freedom in one direction. The end knuckle forms a finger bending action around its end joint. 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. The magnitude of the force reacts to the contact object, and the nail rotates at the same time. The torque is generally used to evaluate the interaction of the rotation of the object. Based on this, as an improvement, Figure 6 The diagram 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, and 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 on the second force-bearing area 22a, the artificial nail is supported by the first fulcrum 221 to generate a first rotational displacement 222, and 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 in 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 The figure shows the position and lever arm setting of the first fulcrum 221 when the normal force is from top to bottom in an elastic or compressive 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 under the normal force F2. After the power arm L1 is greater than the resistance arm L2 to amplify the force, the second pressure sensor 223 detects the second unidimensional force F3 generated by the rotation of the nail. Since L1 and L2 are known, the force F2*arm L1 of the nail = the force F3*arm L2 given to the pressure sensor by the nail. The processing module outputs the normal force and / or torque acting on the second force-bearing area according to the second unidimensional force and the corresponding arm. Since the terminal knuckle 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 anthropomorphize the nail to extend the nail to achieve the measurement of the force magnitude and torque, meeting the measurement requirements of the nail normal force and torque.

[0041] further, Figure 4 The first fulcrum 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 the external object to generate Figure 6 The positive normal force from bottom to top, the second pressure sensor 223 is fixed in the space below the root of the nail, such as when performing a scratching or picking action, the positive normal force produces a slight rotation of the nail to form a nail mechanics measurement. Further, 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 the artificial nail to slide. The inner side wall of the groove and the second pressure sensor clamping enhance the overall stability of the structure, and the top surface of the root of the nail forms an abutment with the sensor position to guide the nail to translate under the negative normal force.

[0042] Figure 8 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 lower edge of the front edge of the nail contacts the external object, guiding the force application point on the second force-bearing area. The front edge of the nail extends outward by 5%-50% of the radial length of the nail body to form 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 second force-bearing area is limited to the acceptable range of error.

[0043] On this basis, Figure 9a The force on the upper surface of the nail is shown. The upper surface of the artificial nail exposed at the end of the finger joint is the third force area 23a that contacts the external object. The second pressure sensor 231 with autonomous elastic recovery after pressing is arranged under the third force area 23a of the nail to support the nail and detect the third unidimensional force. For example, when performing an elastic or pressing 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 numerical 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 according to the third unidimensional force. Further, Figure 9a The diagram shows that the second pressure sensor 223 and the third pressure sensor 231 are arranged on the same side. At this time, the force sensors 223 and 231 are located together on the bottom surface of the artificial nail as a load, and the space at the top of the finger pad at the bottom of the nail is used as a storage, which is conducive to the compact structure of the pressure detection component on the terminal knuckle. More preferably, the upper edge of the notch of the slot 300 is reused as the first fulcrum, and the use of the upper edge of the notch as the first fulcrum further realizes a compact structure, which is conducive to the terminal knuckle simulating the size of a human finger.

[0044] The present invention is based on the consideration that the terminal knuckle has only one degree of rotational freedom in one direction, and decomposes and senses the force on the nail. The force condition of the nail is comprehensively evaluated through the positive normal force and torque, negative normal force, and end radial force on the nail, thereby realizing nail force perception. At the same time, the force perception task in three directions is allocated to three sensors at different positions, which is beneficial 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 plurality of rows and columns of electrode dot arrays, and the electrode dot arrays are used to sense the approach of an object to the force-bearing area and / or the contact on the force-bearing area. The electrode dot arrays 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, Fig.10 The arrangement of the electrode array for sensing the third force zone is given. Fig.10In the figure, the flexible FPC board 401 is attached to the bottom surface of the nail below the third force-bearing area, the sensing electrodes 400 form a dot matrix distributed on the FPC, and the nail presses the third 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 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, and the processing module couples 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, and 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 mutual capacitance and / or self-capacitance of the electrodes in the contact area and the electrodes in the non-contact area on the dot matrix have significant differences, and the contact boundary and position of the object are sensed, and the force point and / or force area are output.

[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 improved solution, the artificial nail includes a main body, and 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 actuating device 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 solution can be arranged so that the front edge of the nail is extended from the inner cavity of the main body by a spring, and the rear end of the front edge abuts against the inner cavity through a spring. The front edge is locked by a push-type buckle structure when it moves to a first extended position and a second retracted position. The push-type buckle 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 present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A pressure detection component for sensing the force on the end of a robot nail, characterized by: Including terminal knuckle, artificial nail, and processing module; The artificial nail is installed on the terminal knuckle, the rigidity of the nail is set to be above 2 Mohs, the front edge of the nail extends outward from the knuckle tip, and the end of the front edge of the nail serves as the first force-bearing area to physically contact with an external object; The artificial nail is connected to the terminal knuckle by sliding along the fingertip direction, and the artificial nail slides toward the knuckle under the force in the first force-bearing area, and at least one first pressure sensor with autonomous elastic recovery after being pressed is fixed on the sliding path to detect the first unidimensional force, and the outer diameter of the pressure sensor is configured to be at most 100% of the maximum size of the nail; The processing module is coupled to the first pressure sensor and is used to output the force applied to 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 front edge of the nail serves as the second force-bearing area that contacts external objects; The terminal finger joint is provided with a first fulcrum acting on the artificial nail, and under the action of the normal force of the nail in the second force-bearing area, the artificial nail is supported by the first fulcrum to generate 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 the 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 according to 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 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 clamp 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.

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

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 the third force-bearing area in contact with external objects; At least one third pressure sensor having 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 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 matrix for sensing the approach of an object to the force-bearing area and / or the contact of an object on the force-bearing area; The capacitance-to-digital conversion circuit couples each sensing electrode in the electrode matrix 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 sensing the approach of an external object and / or output a force point position and / or a force area acting on the force area 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 assembly 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 arranged 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 at least covers a partial 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.

12. A bionic finger, characterized in that: A pressure detection component comprising any one of claims 1-11.

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