A miniature self-decoupling three-dimensional force sensor

Abstract

The present invention proposes a miniature self-decoupling three-dimensional force sensor, which relates to the field of multi-dimensional force sensors and is composed of an inductance measurement unit, a coil, a metal film, an elastomer, a base, and a shell. The coil is fixed to the base in a three-dimensional orthogonal layout, the inductance measurement module is fixed to the base in a folding structure, the metal film is fixed to the inner surface of the shell in a three-dimensional orthogonal layout, and the elastomer converts the three-dimensional force applied to the shell into a three-dimensional displacement. The three mutually orthogonal coils respectively detect the displacement of the metal film parallel to them through the eddy current effect. There is a strong coupling between the mutually parallel coils and the metal film that changes with the displacement. The coil is only sensitive to the normal displacement of the metal film parallel to it, and is not sensitive to the displacement in other directions. Therefore, the original data of the sensor when measuring the force output in the three directions of xyz has very low inter-axis coupling, and no complex calibration decoupling is required. The present invention solves the problems of large inter-axis coupling and complex calibration decoupling of multi-dimensional force sensors.

Description

Technical Field

[0001] The invention belongs to the field of multi-dimensional force sensors, and in particular relates to a miniature self-decoupling three-dimensional force sensor. Background Art

[0002] With the development of science and technology, the measurement of three-dimensional force has received more and more attention, and its related technologies can be applied to many fields, the most widely of which is intelligent robot force perception. Three-dimensional force sensors that can simultaneously measure shear force and normal force can assist robots in completing various complex operations, improve the robot's control ability, and help robots interact with the external environment. Especially in the development of robot dexterous hands, miniature three-dimensional force sensors that can be embedded in robot fingers are crucial. Miniature three-dimensional force sensors also play an important role in minimally invasive surgery, acupuncture, palpation and other fields. These scenarios require sensors to have a smaller size, and the integrated structure facilitates the integration of the entire system. At present, the three-dimensional force sensor technology based on resistance strain gauges / silicon strain gauges is relatively mature, but its miniaturization and integration are difficult to achieve, and the pasting of its strain gauges is relatively complicated, resulting in its high cost. For the miniature three-dimensional force sensor based on fiber Bragg grating (FBG), the size can be very small, which is suitable for the measurement of tiny forces, but its signal processing module is complex, expensive, and large in size. There are also some miniature three-dimensional force sensors based on the principle of capacitance measurement, which have the characteristics of high sensitivity and temperature stability, but are easily affected by environmental humidity and dust. These three-dimensional force sensors based on different principles all require more complex calibration decoupling to convert the electrical signals of the sensitive elements into output force signals. However, for miniature three-dimensional force sensors, their small size makes it difficult to fix and calibrate the sensors, and special calibration equipment needs to be developed to achieve calibration decoupling of three-dimensional force.

[0003] Therefore, there is an urgent need for miniature three-dimensional force sensors with self-decoupling characteristics for use in situations with strict size restrictions, such as humanoid robot dexterous hands and biomedical instruments. Summary of the invention

[0004] In order to solve the problems of large inter-axis coupling and complex calibration decoupling of multi-dimensional force sensors, the present invention provides a miniature self-decoupling three-dimensional force sensor based on the eddy current effect. The miniature self-decoupling three-dimensional force sensor is based on the displacement measurement method. The three coils and the corresponding three metal films of the miniature self-decoupling three-dimensional force sensor are arranged in a three-dimensional orthogonal structure. This ingenious arrangement enables the sensor to monitor the three-dimensional displacement at the same time with very small coupling, and then the conversion of three-dimensional displacement to three-dimensional force is realized with the help of an intermediate elastic body. The inductance measurement module of the miniature self-decoupling three-dimensional force sensor is integrated into the sensor through a folded structure, realizing the function of integrated self-decoupling.

[0005] In order to achieve the above object, the present invention adopts the following technical scheme:

[0006] A miniature self-decoupling three-dimensional force sensor, comprising a housing, an inductance measurement module, a data communication line, a coil Lz, a coil Lx, a coil Ly, an elastic body, a base, a metal film in the z-axis direction, a metal film in the x-axis direction, and a metal film in the y-axis direction; the coil Lz, the coil Lx, and the coil Ly are arranged in a three-dimensional orthogonal structure and fixed on three mutually orthogonal planes of the base; the metal film in the z-axis direction, the metal film in the x-axis direction, and the metal film in the y-axis direction are fixed on the inner side of the housing, arranged in a three-dimensional orthogonal structure, and are one-to-one with the coil Lz, the coil Lx, and the coil Ly. The inductance measurement module is processed by a flexible circuit board process and is fixed on three mutually orthogonal planes of the base and two planes other than the bottom surface in a folded shape. The shell and the base are connected as a whole through an intermediate elastic body. The elastic body converts the three-dimensional force borne by the shell into a three-dimensional displacement. The data communication line passes through the bottom surface of the base. The coil Lz, the coil Lx, and the coil Ly arranged in a three-dimensional orthogonal structure and the corresponding z-axis direction metal film, the x-axis direction metal film, and the y-axis direction metal film arranged in a three-dimensional orthogonal structure jointly realize the self-decoupling characteristics of the sensor.

[0007] Optionally, the metal film in the z-axis direction, the metal film in the x-axis direction, and the metal film in the y-axis direction are three metal films separated from each other.

[0008] Optionally, the materials of the metal film in the z-axis direction, the metal film in the x-axis direction, and the metal film in the y-axis direction are conductive materials.

[0009] Optionally, the shell is made of non-conductive material.

[0010] Optionally, the inductance measurement module is integrated into the interior of the housing in a form folded 90 degrees.

[0011] Optionally, the inductance measurement module is used to measure the inductance of the three coils. The change in inductance is caused by the change in the distance between the metal film and the coil, and the inductance value is used to measure the position of the metal film relative to the coil.

[0012] Optionally, the metal film is a conductive metal material such as copper, aluminum, gold, silver and alloys thereof.

[0013] Optionally, the inductance measurement module is integrated into the interior of the sensor, thereby ensuring the integral integration of the sensor and reducing the influence of the external environment on the inductance measurement module.

[0014] Optionally, the housing and the base are connected together via an elastic body, thereby ensuring that the displacement of the housing can be converted into the force borne by the sensor.

[0015] Optionally, the three coils may be coils wound with metal wires such as copper, or other printed circuit board coils, and their shapes may be two-dimensional or three-dimensional shapes such as circular, square, and triangular.

[0016] Optionally, the size of the metal film is larger than the size of the coil, and the three coils generate strong electromagnetic coupling with the metal films parallel to each other and weak electromagnetic coupling with the three-dimensional orthogonal metal films. The three coils monitor the displacement of one axis respectively, and there is very little coupling between the three axes, thereby realizing the self-decoupling characteristics of the sensor itself. The structural layout using a three-dimensional orthogonal form greatly reduces the overall size of the sensor.

[0017] The three mutually orthogonal coils detect the displacement of the metal film parallel to them through the eddy current effect. The elastic body converts the three-dimensional force applied to the shell into a three-dimensional displacement. There is a strong coupling between the mutually parallel coils and the metal film that changes with the displacement. The coil is only sensitive to the normal displacement of the metal film parallel to it, and is insensitive to the displacement in other directions. Therefore, the raw data of the sensor when measuring the force output in the three directions of the xyz axis has very low inter-axis coupling, and no complex calibration decoupling is required.

[0018] Beneficial effects:

[0019] The present invention is a three-dimensional force sensor based on the principle of three-dimensional displacement measurement. It has a compact structure and a clever three-dimensional orthogonal layout, which allows the sensor to have both small size and three-dimensional force self-decoupling characteristics. The folded inductance measurement module also further improves the integration characteristics of the sensor itself. The basic principle of the present invention is that the high-frequency alternating current in the coil will produce an eddy current effect in the metal film, thereby changing the inductance value of the coil, and the inductance value changes with the distance between the metal film and the coil. The self-decoupling characteristic of the sensor itself is due to the fact that the coupling between the coil and the metal film parallel to it is relatively strong, and the coupling between the coil and the metal film perpendicular to it is very weak.

[0020] The present invention realizes the measurement of three-dimensional force by measuring three-dimensional displacement. The size of the sensor prototype is 9.8mm×9.8mm×9.8mm, the normal force Fz range reaches 10N, and the shear force Fx, Fy range reaches 5N. The output crosstalk of the sensor is less than 3% of the full scale. At the same time, the elastomer of the sensor can also be made of rigid materials such as metal to increase the range of the sensor, or flexible silicone and other materials can be selected to improve the sensor's rigid impact ability. The sensor can be well integrated into the robot's dexterous fingertips, providing force perception for the robot's dexterous hands, and helping the robot to perform various complex operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 ( a ) is an exploded view of parts of a miniature self-decoupling three-dimensional force sensor of the present invention;

[0022] FIG1( b ) is an exploded view of parts of a miniature self-decoupling three-dimensional force sensor of the present invention from another perspective;

[0023] Figure 2 The three-view diagram and the three-dimensional diagram of a miniature self-decoupling three-dimensional force sensor of the present invention are shown;

[0024] Figure 3 It is a schematic diagram of a three-dimensional orthogonal arrangement of the coil and the corresponding metal film of the present invention;

[0025] FIG4 (a) is a graph showing the relationship between the inductance of coil Lx and coil Lz as the z-axis displacement dz of the metal film changes;

[0026] FIG4( b ) is a graph showing the relationship between the inductance of coil Lx and coil Lz as the x-axis displacement dx of the metal film changes;

[0027] FIG5 (a) is a diagram showing the relationship between the inductance of coil Lx, coil Ly, and coil Lz and Fz;

[0028] FIG5( b ) is a diagram showing the relationship between the inductance of coil Lx, coil Ly, and coil Lz and Fx;

[0029] FIG5( c ) is a diagram showing the relationship between the inductance of coil Lx, coil Ly, and coil Lz and Fy;

[0030] FIG5( d ) is a graph showing the relationship between the inductance of coil Lx, coil Ly, and coil Lz and Fr;

[0031] Figure 6 (a) is a comparison of the normal force Fz of the sensor after calibration and the triangular wave output of the reference sensor at a force of 0.04N;

[0032] Figure 6 (b) shows the shear force of the sensor after calibration Comparison chart of triangle wave output with reference sensor at 0.02N force;

[0033] Figure 6 (c) shows the output response of the sensor when struck by an L-shaped silicone block weighing only 0.05 g;

[0034] Figure 6(d) shows the output response of the sensor when a feather weighing 0.32 g slides.

[0035] Among them, the figure markings are: 1-housing; 2-inductance measurement module; 3-data communication line; 4-coil Lz; 5-coil Lx; 6-coil Ly; 7-elastic body; 8-base; 9-metal film in the z-axis direction; 10-metal film in the x-axis direction; 11-metal film in the y-axis direction; 12-bump; 13-opening. DETAILED DESCRIPTION

[0036] The specific implementation method of the present invention for realizing three-dimensional force self-decoupling is described below with reference to the accompanying drawings. The present invention belongs to a three-dimensional force sensor based on the displacement measurement principle, using inductance measurement as the basic measurement means, and realizing small size and self-decoupling characteristics through three-dimensional orthogonal arrangement.

[0037] As shown in Figure 1(a) and Figure 1(b), Figure 2 As shown, a miniature self-decoupling three-dimensional force sensor of the present invention includes a housing 1, an inductance measurement module 2, a data communication line 3, a coil Lz 4, a coil Lx 5, a coil Ly 6, an elastic body 7, a base 8, a metal film 9 in the z-axis direction, a metal film 10 in the x-axis direction, and a metal film 11 in the y-axis direction. Among them, the base 8 is a cube, and its bottom surface is a square. Above the bottom surface is a convex block 12, and the convex block 12 is L-shaped, including a step-like structure at the bottom and a protrusion at the top. The top surface of the convex block 12, one side surface of the L-shaped convex block, and the rectangular surface of the convex block constitute three mutually orthogonal surfaces, and the coil Lz 4, the coil Lx 5, and the coil Ly 6 are respectively embedded in these three mutually orthogonal surfaces.

[0038] The inductance measurement module 2 adopts the flexible printed circuit (FPCB) process and can be bent, so the inductance measurement module 2 is installed on the other two sides of the base 8 in a form of folding at 90 degrees, and the outer surface is flush with the surface of the stepped structure of the base 8, in order to fully utilize the space of the base 8 and reduce the volume under the premise of ensuring integration. An opening 13 is provided above the stepped structure of the protrusion 12, and the data communication line 3 of the inductance measurement module 2 passes through the bottom surface of the base 8 through the opening 13.

[0039] The inductance measurement module 2 can realize the simultaneous measurement of the inductance of coil Lz 4, coil Lx 5, and coil Ly 6. The pins of coil Lz 4, coil Lx 5, and coil Ly 6 are manually soldered to the inductance measurement module 2 by flying wires, and the inductance measurement is realized through the LC resonant circuit. The measured data interacts with the host computer through iic communication.

[0040] The sensor is loaded with force through a linear translation stage with a linear encoder. There is a commercial force sensor at the loading point. During the loading process, the inductance values ​​of coil Lz 4, coil Lx 5, and coil Ly 6 are read simultaneously. At the same time, the measurement value of the commercial force sensor and the displacement value of the linear encoder on the linear translation stage are read. The relationship between displacement, force, and inductance is established through data fitting.

[0041] At the same time, the z-axis direction metal film 9, the x-axis direction metal film 10, and the y-axis direction metal film 11 are arranged on the inner side of the housing 1 in a three-dimensional orthogonal layout (eg Figure 3As shown), the size of the metal film is larger than the size of the coil, the three surfaces on which the metal film 9 in the z-axis direction, the metal film 10 in the x-axis direction, and the metal film 11 in the y-axis direction are installed correspond one to one with the three surfaces in which the coils Lz 4, Lx 5, and Ly 6 are embedded, and the metal film 9 in the z-axis direction, the metal film 10 in the x-axis direction, and the metal film 11 in the y-axis direction move synchronously with the movement of the housing 1.

[0042] The elastic body 7 is a square ring structure, the bottom is a square ring with vertical edges, and a variable opening square ring structure is arranged above the square ring, and the upper opening of the variable opening square ring structure is smaller than the lower opening. The height of the vertical square ring at the bottom of the elastic body 7 is the same as the height of the step-shaped structure of the protrusion 12 of the base 8.

[0043] The shell 1 and the base 8 are connected together through the elastic body 7, the bottom surface of the elastic body 7 is bonded to the bottom surface of the shell 1, and the top surface of the elastic body 7 is bonded to the shell 1. The inner wall of the shell 1 is provided with a square ring that matches the vertical side of the elastic body 7 and a structure that changes into an open square ring structure. After the shell 1 is connected to the base 8, the whole forms a cubic structure.

[0044] The three-dimensional displacement of the housing 1 with the metal film 9 in the z-axis direction, the metal film 10 in the x-axis direction, and the metal film 11 in the y-axis direction can be detected by the inductance values ​​of the coils Lz 4, Lx 5, and Ly 6. Since the housing 1 and the elastic body 7 are connected together, the displacement of the housing 1 is converted to the elastic body 7, causing the elastic body 7 to deform, thereby realizing the change of displacement to force.

[0045] The conversion of three-dimensional force requires additional calibration. With the help of a high-precision linear stage with a linear encoder, the sensor is loaded with force. A commercial force sensor is installed on the linear stage. The force loading is achieved by controlling the movement of the linear stage. During the loading process, the coil inductance value, loading force, and displacement of the linear stage can be recorded simultaneously, thereby establishing the relationship between displacement-force-inductance. The sensor can be calibrated by data fitting. Data collection is achieved through a program developed by the host computer.

[0046] The bottom surface of the base 8 is used to arrange the data communication line 3 and the mounting screw holes. This three-dimensional layout ensures that the sensor is integrated into a space of only 9.8mm×9.8mm×9.8mm in a very compact layout, significantly reducing the size of the sensor.

[0047] Preferably, the elastic body 7 is cast by silicone, and its bottom surface is glued to the base 8 by glue, and the top surface of the elastic body 7 is glued to the shell 1 by glue.

[0048] The overall structure of the invention is similar to a cube or a cuboid, and is easy to be integrated into the dexterous fingertips of a robot.

[0049] like Figure 3 As shown, the coil Lz 4, coil Lx 5, and coil Ly 6 of the present invention constitute a sensitive element coil, which forms a three-dimensional orthogonal arrangement with the corresponding z-axis direction metal film 9, x-axis direction metal film 10, and y-axis direction metal film 11. The three-dimensional orthogonal arrangement of coil Lz 4, coil Lx 5, and coil Ly 6 is a key factor in achieving three-dimensional force self-decoupling. Coil Lz 4, coil Lx5, and coil Ly 6 correspond to the z-axis direction metal film 9, the x-axis direction metal film 10, and the y-axis direction metal film 11, respectively.

[0050] Each coil is parallel to its corresponding metal film and perpendicular to the other two metal films. There is a certain distance between the three coils and the corresponding metal films, which are represented by dx, dy, and dz respectively.

[0051] The coil displacement measurement is realized according to the principle of eddy current effect. By applying high-frequency alternating current to each coil, an alternating magnetic field is stimulated. When the metal film is close to the corresponding coil, according to Faraday's law of electromagnetic induction, the surface of the metal film will respond quickly and generate an eddy current field. These eddy current fields, as the source of the secondary magnetic field, will produce an alternating magnetic field in the opposite direction of the original magnetic field, thereby causing the change of the inductance of the coil. This process is the key to realizing multi-dimensional force measurement. The core of realizing accurate detection of multi-dimensional force lies in capturing the tiny displacement of the metal film. The key to realizing self-decoupling of the sensor is that when the size of the metal film is larger than the size of the coil, the coil only generates a strong electromagnetic coupling that changes with the displacement with the metal film parallel to it. For example, the coil Lz 4 has a strong coupling with the metal film 9 in the z-axis direction that changes with the displacement, and has a weaker electromagnetic coupling with the metal film 10 in the x-axis direction and the metal film 11 in the y-axis direction that changes with the displacement. The same applies to the other directions.

[0052] FIG4 (a) shows the change of the inductance of coil Lz4 and coil Lx5 with the z-axis displacement dz of the housing 1 along the z-axis. Due to the symmetry between the x-axis and the y-axis, only coil Lz4 and coil Lx5 are described. The metal film 9 in the z-axis direction, the metal film 10 in the x-axis direction, and the metal film 11 in the y-axis direction are fixed on the inner side of the housing 1 in a three-dimensional orthogonal form, and the three move together with the displacement of the housing 1. It can be seen that as the housing 1 moves along the z-axis direction, all metal films are displaced synchronously. At this time, the distance between coil Lz4 and the metal film in the z-axis direction decreases, resulting in a rapid decrease in the inductance of coil Lz4. For coil Lx5, the z-axis displacement does not change the horizontal distance between the metal film in the x-axis direction and coil Lx5. Although the vertical distance between the metal film in the z-axis direction and coil Lx5 decreases, its effect on the change of the inductance of coil Lx5 is small.

[0053] FIG4 (b) is a graph showing the change of the inductance values ​​of coils Lz 4 and Lx 5 with the x-axis displacement dx of the housing 1 along the x-axis. It can be seen that as the housing 1 moves along the x-axis, all metal films are displaced synchronously. At this time, the distance between coil Lx 5 and the metal film in the x-axis direction decreases, causing the inductance of coil Lx 5 to decrease rapidly. For coil Lz 4, the x-axis displacement does not change the distance between the metal film and coil Lz 4 in the z-axis direction. Although the distance between the metal film and coil Lz 4 in the x-axis direction decreases, it has little effect on the change of the inductance of coil Lz 4. This significant difference enables the sensor proposed in the invention to have a self-decoupling characteristic in three-dimensional displacement, with almost no mutual influence. This is the most critical feature of the present invention. In summary, the change in the inductance of the coil shows a strong coupling relationship with the change in the spacing between the parallel metal films, and a weak coupling relationship with the change in the spacing between the perpendicular metal films.

[0054] Figure 5 (a) shows the relationship between the inductance of coil Lx 5, coil Ly 6, coil Lz 4 and the normal force Fz borne by the sensor along the z-axis. By referring to the uniaxial force sensor and the displacement stage, the sensor is loaded. It can be seen that for the loading of the z-axis force, the inductance of coil Lz 4 changes significantly, and the other inductances hardly change. However, due to assembly errors, etc., 100% decoupling cannot be achieved. Similarly, Figure 5 (b) shows the relationship between the inductance of coil Lx 5, coil Ly 6, coil Lz 4 and the lateral force Fx borne by the sensor along the x-axis direction. Figure 5 (c) shows the relationship between the inductance of coil Lx 5, coil Ly 6, coil Lz 4 and the shear force Fy borne by the sensor along the y-axis direction. Figure 5 (d) shows the relationship between the inductance of coil Lx 5, coil Ly 6, coil Lz 4 and Fr. Fr represents the loading force at a position 45° from the positive x-axis to the positive y-axis along the lateral x-axis of the sensor. According to Figure 5 (a) to Figure 5 (d), it can be seen that the sensor has a small coupling. Without any calibration decoupling, the coupling between the three axes of the sensor is about 1%-3%. If multi-axis fitting is performed using the least squares method, the degree of coupling can be further reduced.

[0055] As shown in Figure 6 (a), Figure 6 (b), Figure 6 (c), and Figure 6 (d), the output response of the sensor to a tiny force shows that the sensor has a high resolution. As shown in Figure 6 (a), the normal force Fz of the sensor after calibration is compared with the triangular wave output of the reference sensor at a force of 0.04N. It can be seen that the two can be well matched, and the maximum error between them is less than 5mN. Figure 6 (b) is the triangular wave output comparison of the shear force Fx of the sensor after calibration and the reference sensor at a force of 0.02N. The shear force has better sensitivity and resolution than the normal force. Figure 6 (c) is the output response of the sensor when it is hit by an L-shaped silicone block weighing only 0.05g. It can be observed that the minimum output resolution of the sensor is less than 5mN. Figure 6 (d) is the output response of the sensor when a feather weighing 0.32g slides, and its limit resolution is less than 1mN. After calculation, it can be obtained that the resolution of the sensor prototype of the present invention is 2mN in the z-axis direction, and the resolution on the x-axis and y-axis is better than 0.5mN. Of course, if the elastomer is changed, the sensor range and resolution can also be changed.

[0056] According to some embodiments of the present invention, the sensor can be used for force sensing of robot dexterous fingertips and some medical instruments with strict volume restrictions and requiring force sensing. These parts require a compact and fully integrated system, and the self-decoupling characteristics of the sensor proposed by the present invention also reduce the complexity of sensor calibration. In general, the present invention proposes a new miniature self-decoupling three-dimensional force sensor, which is integrated, does not require complex calibration, has low cost, has the potential for wide application, and can also be integrated as a component of a complex system.

[0057] Parts of the present invention that are not disclosed in detail belong to the common knowledge in the art. Although the above describes the illustrative specific embodiments of the present invention to facilitate the understanding of the present invention by those skilled in the art, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A miniature self-decoupling three-dimensional force sensor, characterized in that: The invention comprises a housing (1), an inductance measurement module (2), a data communication line (3), a coil Lz (4), a coil Lx (5), a coil Ly (6), an elastic body (7), a base (8), a metal film in the z-axis direction (9), a metal film in the x-axis direction (10), and a metal film in the y-axis direction (11); the coil Lz (4), the coil Lx (5), and the coil Ly (6) are arranged in a three-dimensional orthogonal structure and fixed on three mutually orthogonal planes of the base (8); the metal film in the z-axis direction (9), the metal film in the x-axis direction (10), and the metal film in the y-axis direction (11) are fixed on the inner side of the housing (1) and arranged in a three-dimensional orthogonal structure, corresponding to the coil Lz (4), the coil Lx (5), and the coil Ly (6) one by one; the base (8) is a cube, the bottom surface of which is a square, and a convex block (12) is formed above the bottom surface; the convex block (12) is L-shaped, including a step-shaped structure at the bottom and a protrusion at the top; the top surface of the convex block (12) and the L-shaped structure of the convex block (12) are The side surface of the shape and the rectangular surface of the protrusion constitute three mutually orthogonal surfaces, and the coil Lz (4), the coil Lx (5), and the coil Ly (6) are respectively embedded in the three mutually orthogonal surfaces; the inductance measurement module (2) is installed on the other two sides of the base (8) in a form of being folded at 90 degrees; the shell (1) and the base (8) are connected into a whole through an intermediate elastic body (7); the elastic body (7) converts the three-dimensional force borne by the shell (1) into a three-dimensional displacement; the data communication line (3) passes through the bottom surface of the base (8); the coil Lz (4), the coil Lx (5), and the coil Ly (6) arranged in a three-dimensional orthogonal structure and the corresponding z-axis direction metal film (9), x-axis direction metal film (10), and y-axis direction metal film (11) arranged in a three-dimensional orthogonal structure together realize the self-decoupling characteristics of the sensor.

2. A miniature self-decoupling three-dimensional force sensor according to claim 1, characterized in that: The metal film (9) in the z-axis direction, the metal film (10) in the x-axis direction, and the metal film (11) in the y-axis direction are three metal films separated from each other or are a whole.

3. A miniature self-decoupling three-dimensional force sensor according to claim 1, characterized in that: The materials of the metal film (9) in the z-axis direction, the metal film (10) in the x-axis direction, and the metal film (11) in the y-axis direction are conductive materials, and the conductive materials include copper, aluminum, silver, gold, and alloys thereof.

4. The miniature self-decoupling three-dimensional force sensor according to claim 1, characterized in that: The shell (1) is made of non-conductive material.

5. The miniature self-decoupling three-dimensional force sensor according to claim 1, characterized in that: The inductance measurement module (2) is fixed to the base (8) in a form of being folded at 90 degrees.

6. The miniature self-decoupling three-dimensional force sensor according to claim 1, characterized in that: The inductance measurement module is used to measure the inductance of the coil Lz (4), the coil Lx (5), and the coil Ly (6).

7. The miniature self-decoupling three-dimensional force sensor according to claim 1, characterized in that: The coil Lz (4), coil Lx (5), and coil Ly (6) are coils wound with metal wires or printed circuit board coils, and have a two-dimensional or three-dimensional shape.

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