A force measurement module measurement branch and a three-dimensional force sensor

Abstract

The present application discloses a force measurement module measurement branch and a three-dimensional force sensor, which solve the problems of stress concentration and central offset of the transfer beam for transmitting force and displacement. A force measurement module measurement branch includes a cross-section variable beam and an elastic measurement body. The cross-section variable beam is integrally formed in an "X" shape by the confluence of two variable cross-section beam units at the thinnest part of the cross-section. The variable cross-section beam unit is an elastic body beam structure with thick ends and a thin middle. Both end faces of the elastic measurement body are fixedly connected to the ends of one of the cross-section variable beams. Opposite strain gauges are attached to two opposite sides of the elastic measurement body perpendicular to the end faces. The three-dimensional force sensor further includes a base and a force measurement transfer beam. At least three ends of the force measurement module measurement branches are non-radially and uniformly distributed on the side wall of the force measurement transfer beam, and the other ends are fixedly connected to the inner wall of the through cavity of the base, so that the force measurement transfer beam is coaxially installed in the through cavity of the base. The main structure of the present application is integrally processed, without assembly gaps, the mechanism is compact, and the measurement accuracy is high.

Description

Technical Field

[0001] This application relates to the field of multi - dimensional force measurement, especially to the measurement branch of the force - measuring module and three - dimensional force sensors. Background Art

[0002] Multi - dimensional force sensors are widely used in fields such as robotics, product testing, aerospace, etc. because they can detect multi - dimensional force information in space.

[0003] All multi - dimensional force sensors disclosed in the prior art are of an assembled structure, and the influence of the assembly gap on the measurement accuracy is inevitable. A multi - dimensional force sensor with high measurement accuracy, no assembly gap, and a compact structure has become a currently scarce product.

[0004] In the prior art, most multi - dimensional force sensors use elastic beams with equal cross - sections to transmit force and displacement. Although when an elastic beam with an equal cross - section is subjected to an external force, the phenomenon of stress concentration can be eliminated, when it is subjected to a non - radial external force, the center of the equal - cross - section beam shifts significantly. Moreover, in a conventional mechanical transmission system, force is transmitted through rigid kinematic pairs, and there are inevitably gaps, friction, and wear between components.

[0005] A variable cross - section beam can transmit force and displacement through the elastic deformation of the material, completely eliminating the dead - space and mechanical friction during the transmission of the kinematic pair. However, the most common variable cross - section beam is formed by cutting two symmetrical notches on a cuboid material, so that the structure produces a small rotational effect under the action of an external load. When a variable cross - section beam with ordinary notches is subjected to a non - radial force, the stress is mainly concentrated in the weakest area, affecting the force transmission effect.

[0006] Therefore, a device is needed to solve the problems of stress concentration and beam center offset. Summary of the Invention

[0007] The embodiments of this application provide a measurement branch of a force - measuring module and a three - dimensional force sensor, which solve the problems of stress concentration and center offset of the transmission beam for transmitting force and displacement in the prior art.

[0008] The embodiments of this application also provide a measurement branch of a force - measuring module, which includes a cross - variable cross - section beam and an elastic measuring body. The cross - variable cross - section beam is integrally formed in an "X" shape by the confluence of two variable cross - section beam units at the thinnest part of the cross - section. The variable cross - section beam unit is an elastic body beam structure that is thick at both ends and thin in the middle. Both end faces of the elastic measuring body are fixedly connected to the ends of one of the cross - variable cross - section beams. Opposite strain gauges are attached to two opposite sides of the elastic measuring body perpendicular to the end faces.

[0009] Preferably, the elastic measuring body is a rectangular structure with a rectangular through - hole. The cross - section of the elastic measuring body perpendicular to the rectangular through - hole is in a "mouth" shape. The thickness of the side wall of the rectangular structure fixedly connected to the cross - variable cross - section beam is greater than the side wall with the attached strain gauges.

[0010] On the other hand, the present application also provides a three-dimensional force sensor, which includes a base and a force-measuring transfer beam, and also includes the measuring branch of the force-measuring module described in the above embodiment. A cylindrical through cavity is formed in the base. The force-measuring transfer beam is cylindrical, and a threaded through hole is provided at the center of the cylinder. One end of the measuring branch of the force-measuring module is non-radially arranged on the side wall of the force-measuring transfer beam, and the other end is fixedly connected to the inner wall of the through cavity of the base, so that the force-measuring transfer beam is coaxially installed in the through cavity of the base.

[0011] Further, the base, the force-measuring transfer beam, and the measuring branch of the force-measuring module are integrally formed elastic members.

[0012] Preferably, a first notch is formed on the side wall of the force-measuring transfer beam. A perpendicular line of the first connection surface on the first notch is tangent to the inner circle concentric with the force-measuring transfer beam. The first connection surface is used to fixedly connect one end of the measuring branch of the force-measuring module.

[0013] Further, the base is cylindrical. A plurality of mounting through holes parallel to the axis are uniformly formed on the upper surface of the base around the through cavity. The mounting through holes are used to fix the three-dimensional force sensor.

[0014] Further preferably, a ring-shaped boss protruding from the inner wall in the circumferential direction is provided on the base, and a second notch corresponding to the first notch is provided on the ring-shaped boss. A second connection surface parallel to the opposite first connection surface is provided on the second notch. The second connection interface is used to fixedly connect the other end of the measuring branch of the force-measuring module.

[0015] Preferably, both the first notch and the second notch are symmetrically distributed in three, and the three notches are 120 degrees apart from each other.

[0016] Further, an upper protective cover and a lower protective cover are also included. The upper protective cover and the lower protective cover are disc structures. They are fixedly connected to the base and cover the upper and lower openings of the through cavity of the base respectively. A circular opening facing the threaded through hole on the force-measuring transfer beam is formed on the upper protective cover or the lower protective cover.

[0017] Further preferably, the upper and lower protective covers are respectively installed on the upper and lower bottom surfaces of the ring-shaped boss on the base. The thickness of the force-measuring transfer beam is lower than that of the ring-shaped boss. A coaxial cylindrical boss is provided on the force-measuring transfer beam, and the cylindrical boss extends out from the circular opening on the upper protective cover or the lower protective cover.

[0018] The above at least one technical solution adopted in the embodiment of the present application can achieve the following beneficial effects:

[0019] The three-dimensional force sensor described in this application includes a base, a force-measuring transfer beam, and force-measuring module measurement branches. At least three force-measuring module measurement branches can complete the measurement of two-dimensional forces and torques in a plane, which is easy to realize productization. Moreover, the sensor can eliminate the problem of low stiffness caused by the series connection of a single measurement branch through multiple force-measuring module measurement branches. The base, the force-measuring transfer beam, and the force-measuring module measurement branches are integrally processed, without assembly gaps, the mechanism is compact, and the measurement accuracy is high. The three non-radially uniformly distributed force-measuring module measurement branches have a large structural stiffness. The cross-variable cross-section means that two variable cross-section beams are cross-arranged and converge at one point. When the beam is subjected to a non-radial force, it will rotate slightly around the intersection of the two beams, which can not only improve the stress concentration situation, but also ensure that the center of the beam does not shift. Therefore, the cross-variable cross-section beam has a good effect in the field of force and micro-displacement transmission. Description of the Drawings

[0020] The drawings described herein are used to provide a further understanding of this application, and constitute a part of this application. The schematic embodiments of this application and their descriptions are used to explain this application, and do not constitute an improper limitation of this application. In the drawings:

[0021] Figure 1 It is a structural diagram of an embodiment of a force-measuring module measurement branch of this application;

[0022] Figure 2 It is a structural diagram of an embodiment of a three-dimensional force sensor of this application;

[0023] Figure 3 It is a structural diagram of an embodiment of the base described in this application;

[0024] Figure 4 It is a structural diagram of an embodiment of the force-measuring transfer beam described in this application;

[0025] Figure 5 It is a working schematic diagram of the three-dimensional force sensor of this application;

[0026] Figure 6 It is a structural diagram of an embodiment of the upper protective cover or the lower protective cover described in this application;

[0027] Figure 7 It is a schematic diagram of an embodiment of the installation of the three-dimensional force sensor described in this application. Detailed Embodiments

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0029] The technical solutions provided by the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0030] Figure 1 It is a structural diagram of a measurement branch of a force measurement module according to the present application.

[0031] A force measurement module measurement branch 1 includes a cross-section variable beam 11 and an elastic measurement body 12.

[0032] The cross-section variable beam is integrally formed in an "X" shape by the confluence of two variable cross-section beam units at the thinnest part of the cross-section. The variable cross-section beam unit is an elastic beam structure that is thick at both ends and thin in the middle.

[0033] The cross-section of the variable cross-section beam unit can be cylindrical, rectangular, triangular, or the shape of the street side is not fixed, and no further limitation is made here.

[0034] The thickness change of the variable cross-section beam unit from both ends to the middle can be uniformly transitioned through an arc or through a straight line. For example, the variable cross-section beam unit is similar to the shape composed of two coaxial cones with opposite apex angles. However, this variable cross-section beam is to cut two symmetric incisions on a cuboid material, so that the structure produces a small rotational effect under the action of an external load. When the variable cross-section beam with a common incision is subjected to a non-radial force, the stress is mainly concentrated in the weakest area, which affects the force transmission effect. Although the equal cross-section elastic beam can eliminate the stress concentration phenomenon when subjected to an external force, when subjected to a non-radial external force, the center of the variable cross-section beam shifts significantly. Therefore, preferably, the thickness change of the variable cross-section beam unit from both ends to the middle can be uniformly transitioned through an arc.

[0035] Two variable cross-section beam units are integrally formed in an "X" shape by confluence at the thinnest part of the cross-section to form the cross-section variable beam 11.

[0036] For example, the force measurement module measurement branch includes a first cross-section variable beam 111, an elastic measurement body, and a second cross-section variable beam 112. Both the first cross-section variable beam 111 and the second cross-section variable beam 112 are composed of two variable cross-section beam units arranged in an "X" shape, and the two variable cross-section beam units are confluent and integrally formed at the thinnest part of the cross-section thickness.

[0037] Both end faces of the elastic measurement body 12 are fixedly connected to the ends of one of the cross-section variable beams 11. Opposite strain gauges are attached to two opposite sides of the elastic measurement body 12 perpendicular to the end faces.

[0038] It should be noted that the end of the cross-section variable beam 11 is composed of the ends of two variable cross-section beam units in the same direction. In this application, when it is stated that the end of the cross-section variable beam 11 is fixedly connected to a certain place, it means that the ends of the two variable cross-section units of the cross-section variable beam 11 in the same direction are both fixedly connected to that place.

[0039] The elastic measuring body 12 can be selected as cylindrical, rectangular, or any structure with both ends fixedly connected to the cross-section variable beam 11 and strain gauges that can be attached to the side surface. However, for the "mouth" - shaped elastic measuring body, the two sides in contact with the cross beam are slightly thicker to increase the connection strength, and the other two sides are slightly thinner so that strain gauges can be pasted on the inner and outer surfaces for sensitive measurement. Therefore, preferably, the elastic measuring body 12 is a rectangular structure with a rectangular through - hole. The cross - section of the elastic measuring body 12 perpendicular to the rectangular through - hole is in the shape of a "mouth". The thickness of the side wall of the rectangular structure fixedly connected to the cross - section variable beam 11 is greater than the side wall with strain gauges attached.

[0040] For example, the first cross - section variable beam 111 and the second cross - section variable beam 112 have the same shape and are symmetrically arranged with respect to the elastic measuring body. The cross - section of the elastic measuring body is in the shape of a "mouth". The two sides in contact with the cross - section variable beam are slightly thicker to increase the connection strength, and the other two sides are slightly thinner so that strain gauges can be pasted on the inner and outer surfaces for sensitive measurement.

[0041] Figure 2 This is a structural diagram of an embodiment of a three - dimensional force sensor according to this application.

[0042] A three - dimensional force sensor includes a base 2 and a force - measuring transfer beam 3. It also includes the measuring branch 1 of the force - measuring module described in the above - mentioned embodiment.

[0043] The three - dimensional force sensor can be fixedly connected by screws or other connecting components. However, no matter how precise the assembly is, the assembly gap cannot be avoided. Therefore, preferably, the base, the force - measuring transfer beam, and the measuring branch of the force - measuring module are integrally formed elastic members. Due to the absence of an assembly gap, the device described in this application has high measurement accuracy and a compact structure.

[0044] For example, the three - dimensional force sensor structure is integrally processed, including a base, a measuring branch of the force - measuring module, and a force - measuring transfer beam. The base and the force - measuring transfer beam are connected by three measuring branches of the force - measuring module. The three integral measuring branches of the force - measuring module are evenly distributed, and the three measuring branches of the force - measuring module are mutually at an angle of 120 degrees, around the force - measuring transfer beam, and none of them passes through the central rotation axis of the force - measuring transfer beam.

[0045] Figure 3 This is a structural diagram of an embodiment of the base according to this application.

[0046] A cylindrical through - cavity 21 is opened on the base 2.

[0047] The base 2 can be of any shape. It can be cylindrical, rectangular, or even irregular. No further limitation is made here.

[0048] For example, the base 2 is cylindrical. A number of mounting through-holes 22 parallel to the axis are evenly opened on the upper surface of the base around the through cavity 21. The mounting through-holes are used to fix the three-dimensional force sensor.

[0049] Specifically, the outer surface of the base 2 is cylindrical. 18 mounting through-holes parallel to the axis are evenly distributed on the upper surface for the installation and fixation of the sensor. A through-hole is provided on the cylindrical side for wire routing.

[0050] Since the three-dimensional force sensor of the present application needs to be connected to the device to be measured to complete the test of the device to be measured, there need to be mounting holes on the three-dimensional force sensor for fixing the three-dimensional force sensor on the device to be measured. A number of mounting through-holes are opened on the upper surface of the base 2. The mounting through-holes surround the through cavity and are parallel to the axis, and directly lead from the upper surface to the lower surface. The three-dimensional force sensor of the present application is fixed through 18 through-holes arranged on the base 2.

[0051] A ring-shaped boss 24 can also be provided on the inner surface of the cylindrical base. The upper and lower surfaces of the ring-shaped boss 24 protrude from the inner wall of the ring symmetrically. Three groups of threaded through-holes are provided on the ring-shaped boss 24. The three groups of threaded through-holes are evenly distributed within the circumference. The three groups of threaded holes are 120 degrees apart from each other, and the number of threaded through-holes in each group is three. At least three evenly distributed notches are provided in the circumferential direction of the ring-shaped boss 24 for arranging the measurement branch 1 of the force measurement module.

[0052] Figure 4 This is the structural diagram of the force measurement transfer beam embodiment of the present application.

[0053] The force measurement transfer beam 3 is cylindrical, and a threaded through-hole 31 is provided at the center of the cylinder.

[0054] In use, the object to be measured is connected to the entire three-dimensional force sensor through the threaded through-hole at the center of the integral force measurement transfer beam.

[0055] One end of the measurement branch 1 of the force measurement module is non-radially arranged on the side wall of the force measurement transfer beam 3, and the other end is fixedly connected to the inner wall of the through cavity 21 of the base, so that the force measurement transfer beam 3 is coaxially installed in the through cavity 21 of the base.

[0056] For example, the force measurement transfer beam 3 is cylindrical, a threaded through-hole is provided at the center, and three symmetrically distributed notches are provided on the cylinder for arranging the integral force measurement module measurement branch. The three notches are 120 degrees apart from each other.

[0057] A first notch 32 is formed on the side wall of the force-measuring transmission beam. A perpendicular line of the first connecting surface on the first notch 32 is tangent to the inner circle concentric with the force-measuring transmission beam. The radius of the inner circle is smaller than that of the force-measuring transmission beam. The first connecting surface is used for fixedly connecting one end of the measuring branch of the force-measuring module.

[0058] Through holes are arranged on the cylinder of the force-measuring transmission beam to reduce the self-weight of the side-force transmission beam, and thus reduce the total weight of the sensor.

[0059] For example, through holes 33 are also symmetrically arranged on the cylinder of the force-measuring transmission beam, and the three through holes are mutually 120 degrees.

[0060] For another example, there is a ring-shaped boss 24 protruding from the inner wall of the circumferential ring on the base. The notch on the ring-shaped boss 24 is a second notch 23 corresponding to the first notch 32. There is a second connecting surface on the second notch 23 parallel to the opposite first connecting surface. The second connecting interface is used for fixedly connecting the other end of the measuring branch of the force-measuring module.

[0061] For example, there are three measuring branches 1 of the force-measuring module. For the convenience of processing, preferably, both the first notch 32 and the second notch 23 are three symmetrically distributed ones, and the three notches are mutually 120 degrees.

[0062] Another embodiment is that the force-measuring transmission beam is in the shape of two concentric cylinders with different diameters. The thickness of the large cylinder is smaller than the thickness of the ring-shaped boss on the base, and the small cylinder serves as the cylindrical boss 34, and its thickness is greater than the thickness of the base.

[0063] Figure 5 This is a schematic diagram of the operation of the three-dimensional force sensor of the present application.

[0064] When any two-dimensional force or moment in the plane is applied to the force-measuring transmission beam 3 of the three-dimensional force sensor of the present application, the measuring branch 1 of the force-measuring module can have a small rotation at the intersection of the variable-section beam units of the cross-variable-section beam 11, and any two-dimensional force or moment in the plane can be mapped to the tension or pressure on the middle elastic body of the three integral force-measuring module measuring branches through geometric relationships. By pasting strain gauges on the middle elastic body in the integral force-measuring module measuring branch to form a bridge structure and calibrating the whole three-dimensional force sensor, when a single force-measuring module measuring branch 1 is subjected to tension or pressure, the magnitude of the force can be mapped through the strain of the strain gauge.

[0065] Specifically, a coordinate system is established as Figure 5As shown in the figure, the x-axis is parallel to a measurement branch of a force measurement module. The tension or pressure on the middle elastic body of this measurement branch of the force measurement module is denoted as F1, and the tensions or pressures on the elastic measurement bodies of the other two integral force measurement module measurement branches are denoted as F2 and F3 respectively. The radius of the concentric circle tangent to the three force measurement module measurement branches is denoted as r. When an external force F is applied to the force measurement transfer beam 3 of the three-dimensional force sensor described in this application, the force F can be decomposed into a two-dimensional force Fx and Fy in the plane and a moment Mz around the z-axis. The measurement branch 1 of the force measurement module can undergo a small rotation at the intersection of the variable cross-section beam units of the cross variable cross-section beam 11. Any two-dimensional force or moment in the plane can be mapped to the tensions or pressures on the elastic measurement bodies of the three integral force measurement module measurement branches through geometric relationships.

[0066] The relationship between any force F in the plane and the three force measurement module measurement branches is as follows:

[0067] Fx = F1 - F2×cos60° - F3×cos60°;

[0068] Fy = F3×sin60° - F2×sin60°;

[0069] Mz = F1×r + F2×r + F3×r.

[0070] Figure 6 This is the structure diagram of the upper protective cover or lower protective cover embodiment described in this application.

[0071] Preferably, the three-dimensional force sensor further includes an upper protective cover 4 and a lower protective cover 5. The upper protective cover and the lower protective cover are disk structures. They are fixedly connected to the base and cover the upper and lower openings of the through cavity of the base respectively. A circular opening 6 is provided on the upper protective cover or the lower protective cover opposite to the threaded through hole on the force measurement transfer beam.

[0072] The upper and lower protective covers are respectively installed on the upper and lower bottom surfaces of the annular boss 24 on the base. The thickness of the force measurement transfer beam is lower than that of the annular boss 24.

[0073] For example, the cross-sections of the upper and lower protective covers are both circular. There is 1 circular opening 6 in the middle of the upper protective cover 4, and there is no circular opening in the center of the lower protective cover 5. There are nine circular through holes distributed around the center on both the upper and lower protective covers. The nine circular through holes are divided into three groups, and the three groups of holes are evenly distributed on the upper and lower protective covers, and the three groups of holes are 120 degrees apart from each other.

[0074] For another example, as Figure 3As shown, three groups of threaded through holes 241 are provided on the annular boss 24. The three groups of threaded through holes are evenly distributed within the circumference. The three groups of threaded holes are 120 degrees apart from each other, and the number of threaded through holes in each group is three. There are corresponding threaded holes on the upper protective cover 4 and the lower protective cover 5. The upper protective cover 4 and the lower protective cover 5 are fixedly connected and installed on the annular boss 24 through circular through holes and the threaded through holes.

[0075] The cylindrical boss 34 on the force measuring transmission beam protrudes from the circular opening 6 on the upper protective cover or the lower protective cover. For the convenience of use and maintenance, usually the cylindrical boss 34 is placed upward. Therefore, preferably, a circular opening 6 is provided on the upper protective cover, and the cylindrical boss 34 protrudes upward from the circular opening 6.

[0076] Figure 7 It is a schematic diagram of the installation embodiment of the three-dimensional force sensor described in this application.

[0077] There is a certain gap between the cylindrical boss 34 protruding from the upper surface of the force measuring transmission beam and the circular opening 6 in the middle of the upper protective cover, that is, the radius of the circular opening is slightly larger than that of the cylindrical boss 34. The upper and lower surfaces of the upper and lower protective covers are in contact with the upper surface of the annular boss 24 and have a certain gap with the upper surface of the force measuring transmission beam. The upper and lower protective covers are both installed on the integral force measuring module through nine mounting screws 7, nine spring washers 8, and nine flat washers 9.

[0078] The lower surface of the lower protective cover is in contact with the lower surface of the annular boss and has a certain gap with the lower surface of the force measuring transmission beam. The lower protective cover is installed on the three-dimensional force sensor through nine mounting screws 7, nine spring washers 8, and nine flat washers 9.

[0079] The above are only the embodiments of this application and are not used to limit this application. For those skilled in the art, various changes and modifications can be made to this application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the scope of the claims of this application.

Claims

1. A force measurement module measurement branch, characterized in that, It includes a cross variable cross-section beam and an elastic measuring body; The cross variable cross-section beam is integrally formed in an "X" shape by the confluence of two variable cross-section beam units at the thinnest part of the cross-section; The variable cross-section beam unit is an elastic beam structure that is thick at both ends and thin in the middle; Both end faces of the elastic measuring body are fixedly connected to the ends of one of the cross variable cross-section beams; Relative strain gauges are attached to two opposite sides of the elastic measuring body perpendicular to the end faces; The elastic measuring body is a rectangular structure with a rectangular through-hole; The cross-section of the elastic measuring body perpendicular to the rectangular through-hole is in a "mouth" shape; The thickness of the side wall of the rectangular structure fixedly connected to the cross variable cross-section beam is greater than the side wall with the strain gauges attached.

2. A three-dimensional force sensor, comprising a base and a force-measuring transmission beam, characterized in that, It also includes the measuring branch of the force measuring module described in claim 1; A cylindrical through-cavity is opened on the base; The force measuring transmission beam is cylindrical, and a threaded through-hole is provided at the center of the cylinder; One end of the measuring branch of the force measuring module is non-radially arranged on the side wall of the force measuring transmission beam, and the other end is fixedly connected to the inner wall of the through-cavity of the base, so that the force measuring transmission beam is coaxially installed in the through-cavity of the base; At least three of the measuring branches of the force measuring module are evenly distributed on the cylindrical inner surface of the base.

3. The three-dimensional force sensor according to claim 2, characterized in that, The base, the force measuring transmission beam and the measuring branch of the force measuring module are integrally formed elastic parts.

4. The three-dimensional force sensor according to claim 2, characterized in that, A first notch is opened on the side wall of the force measuring transmission beam; A perpendicular line of the first connection surface on the first notch is tangent to the concentric inner circle of the force measuring transmission beam; The first connection surface is used to fixedly connect one end of the measuring branch of the force measuring module.

5. The three-dimensional force sensor according to claim 2, characterized in that, The base is cylindrical; A number of mounting through-holes parallel to the axis are evenly opened on the upper surface of the base around the through-cavity; The mounting through-holes are used to fix the three-dimensional force sensor.

6. The three-dimensional force sensor according to claim 4, wherein There is a ring-shaped convex platform protruding from the inner wall of the base in the circumferential direction, and a second notch corresponding to the first notch is provided on the ring-shaped convex platform; There is a second connection surface on the second notch parallel to the opposite first connection surface; The second connection surface is used to fixedly connect the other end of the measuring branch of the force measuring module.

7. The three-dimensional force sensor according to claim 6, wherein Both the first notch and the second notch are three symmetrically distributed, and the three notches are 120 degrees apart from each other.

8. The three-dimensional force sensor according to any one of claims 2-7, characterized in that It also includes an upper protective cover and a lower protective cover; The upper protective cover and the lower protective cover are disc structures, Fixedly connected to the base, covering the upper and lower openings of the through-cavity of the base respectively; A circular opening is opened on the upper protective cover or the lower protective cover opposite to the threaded through-hole on the force measuring transmission beam.

9. The three-dimensional force sensor according to claim 8, wherein, The upper and lower protective covers are respectively installed on the upper and lower bottom surfaces of the ring-shaped convex platform on the base; The thickness of the force measuring transmission beam is lower than that of the ring-shaped convex platform; There is a coaxial cylindrical convex platform on the force measuring transmission beam, and the cylindrical convex platform extends out from the circular opening on the upper protective cover or the lower protective cover.

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