Full-plane six-dimensional force sensor

Abstract

The invention belongs to the field of mechanical sensors, and discloses a full-plane six-dimensional force sensor. The sensor comprises a fixed table, a central loading table, eight radial beams and four circumferential beams which are arranged on the same central plane in the thickness direction, the radial beams are uniformly arranged between the central loading table and the fixed table at intervals along the circumferential direction; the radial beams which are symmetrical in pairs form a group of radial beams, two groups of radial beams which are perpendicular to each other are Fx-axis radial beams and Fy-axis radial beams respectively, and the other two groups of radial beams are Mz-axis radial beams and Fz-axis radial beams respectively; the four circumferential beams are matched with the four radial beams which are arranged at intervals one by one, and the circumferential beams are vertically and equally divided by the radial beams; the circumferential beams perpendicular to the Fx-axis radial beams are My-axis circumferential beams, and the circumferential beams perpendicular to the Fy-axis radial beams are Mx-axis circumferential beams; the strain gauges are divided into six groups, and each group of strain gauges form an independent full-bridge circuit. According to the invention, inter-dimensional crosstalk is eliminated from a mechanical structure, and the sensor has the advantages of high sensitivity, isotropy, strong overload capability and easy processing.

Description

Technical Field

[0001] This invention belongs to the technical field of mechanical sensors, and more specifically, relates to a full-planar six-dimensional force sensor. Background Technology

[0002] A six-dimensional force sensor is a sensor capable of simultaneously detecting multi-degree-of-freedom force components (Fx, Fy, and Fz) and torques (Mx, My, and Mz) in space. Currently, six-dimensional force sensors are the primary source of force information for robots interacting with their external environment, enhancing their perception capabilities and forming the foundation for robot force control. Furthermore, with the emergence of humanoid robots, robots need to perform more complex and precise tasks, thus necessitating high standards in the design of six-dimensional force sensors for finger joints, including small size, compact structure, and powerful functionality.

[0003] The key technical challenge in designing a six-dimensional force sensor for robot finger joints lies in the structural design of its elastomer. This requires simultaneously considering various static and dynamic performance characteristics of the sensor, including sensitivity, nonlinearity, and interdimensional coupling, as well as the ease and cost of elastomer fabrication, subsequent bonding, and wire bonding processes. Currently, strain gauge six-dimensional force sensors are widely used in force sensors. They can be categorized into cross-planar and full-planar types based on the arrangement of the strain gauges, integral and non-integral types based on the elastomer structure, and beam, wheel, vertical rib, and Stewart types based on the elastomer's structural characteristics. Among these, the cross-beam type sensor is widely used in small six-dimensional force sensors due to its high accuracy and sensitivity, small footprint, and lightweight design. However, traditional cross-beam six-dimensional force sensors have insurmountable inter-dimensional coupling problems. To achieve structural decoupling, metal strain gauges are generally mounted using a cross-planar process. However, metal foil sensors have low sensitivity and can only withstand small overloads. In addition, the size of the pads used is relatively large, while the space of the finger joints is narrow, making mechanical assembly extremely difficult. Another method is to use software decoupling and adopt the calibration matrix method to improve accuracy. However, since matrix calibration is only from an experimental perspective rather than eliminating inter-dimensional interference from a theoretical perspective, the degree of improvement in accuracy is limited.

[0004] Therefore, a six-dimensional force sensor that combines structural coupling, balanced sensitivity in all directions, and simple patch manufacturing process is needed to solve the above technical problems. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a full-planar six-dimensional force sensor to solve the problems of the existing technology in achieving structural coupling, sensitivity balance in all directions and simple patching process.

[0006] To achieve the objectives of this invention, according to a first aspect of this invention, a full-planar six-dimensional force sensor is provided, comprising an elastic body and a strain gauge; The elastic body includes a fixed platform, a central loading platform, eight radial beams and four circumferential beams, and the fixed platform, the central loading platform, the radial beams and the circumferential beams are arranged on the same central plane in the thickness direction; The central loading platform is placed inside the fixed platform, and the eight radial beams are evenly spaced along the circumference between the central loading platform and the fixed platform; wherein, two pairs of radial beams that are symmetrical among the eight radial beams form a group of radial beams, two groups of radial beams that are perpendicular to each other are the Fx-axis radial beam and the Fy-axis radial beam, and the two groups of radial beams that are located between the Fx-axis radial beam and the Fy-axis radial beam are the Mz-axis radial beam and the Fz-axis radial beam, respectively. The four circumferential beams are matched one-to-one with four radial beams of the Fx-axis and Fy-axis radial beams, and the circumferential beams are perpendicularly bisected by the radial beams, so that the eight endpoints of the four circumferential beams are connected sequentially to form a fully symmetrical octagon within the fixed platform; wherein, the circumferential beam perpendicular to the Fx-axis radial beam is the My-axis circumferential beam, and the circumferential beam perpendicular to the Fy-axis radial beam is the Mx-axis circumferential beam; The strain gauges are arranged in 6 groups, respectively on the radial beam of the Fx axis, the radial beam of the Fy axis, the radial beam of the Mz axis, the radial beam of the Fz axis, the circumferential beam of the My axis, and the circumferential beam of the Mx axis. Each group of strain gauges forms an independent full-bridge circuit.

[0007] Preferably, a support beam is provided between adjacent My axis circumferential beams and Mx axis circumferential beams, so that the four circumferential beams and the four support beams are connected end to end to form a fully symmetrical octagonal structure inscribed in the fixed platform.

[0008] Preferably, the strain gauges on the Fx-axis radial beam, the Fy-axis radial beam, the Mz-axis radial beam, and the Fz-axis radial beam are all arranged on two symmetrical radial beams, and the strain gauges on the same radial beam are symmetrically arranged on the upper and lower surfaces in the thickness direction; the strain gauges on the My-axis circumferential beam and the Mx-axis circumferential beam are all arranged on two symmetrical circumferential beams, and the strain gauges on all the circumferential beams are arranged on the same surface in the thickness direction, and the strain gauges on the same circumferential beam are symmetrically arranged based on the extension line of the radial beam.

[0009] Preferably, there are 4 strain gauges on both the Fx-axis radial beam and the Fy-axis radial beam; there are 4 or 8 strain gauges on the Mz-axis radial beam, and 4 strain gauges on the Fz-axis radial beam; there are 4 strain gauges on both the My-axis circumferential beam and the Mx-axis circumferential beam.

[0010] Preferably, the radial beam widths of the Fx-axis radial beam and the Fy-axis radial beam are denoted as a, the radial beam widths of the Mz-axis radial beam and the Fz-axis radial beam are denoted as b, and the width of the circumferential beam is denoted as c, where 1.5a = b = c.

[0011] Preferably, the strain gauge is a silicon strain gauge.

[0012] Preferably, the outer diameter of the fixed platform is 17-85mm; the thickness of the fixed platform is 5-20mm; the radial beam and the circumferential beam have the same thickness, and the thickness of the radial beam and the circumferential beam does not exceed the thickness of the fixed platform and the central loading platform.

[0013] Preferably, the connection between the fixed platform and the circumferential beam, the connection between the circumferential beam and the radial beam, and the connection between the central loading platform and the radial beam are all provided with chamfers.

[0014] Preferably, recessed grooves are provided on the left and right sides of the strain gauges on the Fx-axis radial beam and the Fy-axis radial beam, respectively.

[0015] Preferably, the fixed platform is provided with 8 equidistant threaded holes, and the central loading platform is provided with 4 equidistant threaded holes, the center of each equidistant threaded hole being located on the extension line of the radial beam.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. The all-planar six-dimensional force sensor of this invention incorporates eight radial beams and four circumferential beams, designed as radial beams along the Fx axis, Fy axis, Mz axis, Fz axis, circumferential beams along the My axis, and circumferential beams along the Mx axis. Strain gauges are arranged on the upper and lower surfaces of these radial and circumferential beams to form six sets of Wheatstone bridges. This design divides the strain gauges corresponding to these two opposite strains into two groups through the symmetrical beam design, which are respectively connected to adjacent bridge arms of the measuring bridge. When tensile and compressive stresses occur during elastic deformation, the effective signals in this direction will be superimposed and enhanced. Interference signals (coupling signals) from other directions will cause the strain gauges of adjacent bridge arms to produce resistance changes in the same direction, which cancel each other out in the subtraction operation of the bridge. That is, the voltages of the four strain gauge bridge arms in the coupling direction cancel each other out, directly eliminating interdimensional coupling from the structural design. At the same time, the elastic body adopts a regular octagonal symmetrical design, which effectively balances the sensitivity output in each direction. Furthermore, the all-planar process is used to mount the strain gauges, which reduces the difficulty of wire bonding, the size of the plates, and the difficulty of mechanical assembly. Therefore, the all-planar six-dimensional force sensor of the present invention eliminates interdimensional crosstalk from the mechanical structure, while also possessing the advantages of high sensitivity, isotropy, strong overload capacity and easy processing.

[0017] 2. Preferably, the present invention provides a support beam between the adjacent My axis circumferential beam and Mx axis circumferential beam, so that the four circumferential beams and four support beams are connected end to end to form a fully symmetrical octagonal structure inscribed in the fixed platform, providing protection and overload capacity. When the external force exceeds the design range, the support beam structure can limit further deformation through its own deformation.

[0018] 3. In this invention, the widths of the circumferential beam, the radial beam along the Fz axis, and the radial beam along the Mz axis are preferably 1.5 times the widths of the radial beams along the Fx axis and the Fy axis. Since the sensitivity in the Fx and Fy directions is relatively low, the sensitivity in the Fx and Fy directions is improved by reducing the widths of the radial beams along the Fx and Fy axes, thereby balancing the sensitivity in each direction.

[0019] 4. The present invention preferably uses silicon strain gauges, which are significantly superior to metal strain gauges in terms of sensitivity, stability, signal-to-noise ratio and dynamic characteristics. The sensors manufactured from silicon strain gauges have advantages such as high sensitivity and high stability. At the same time, silicon strain gauges are smaller in size, making them more suitable for fabricating small-sized sensor applications.

[0020] 5. Preferably, the present invention avoids stress concentration by setting chamfers at the structural connection.

[0021] 6. Preferably, the present invention increases sensitivity by setting recessed grooves on the beam along the axial and radial directions to concentrate the strain in the measured area. Attached Figure Description

[0022] Figure 1 This is a top view structural diagram of a fully planar six-dimensional force sensor according to the present invention.

[0023] Figure 2 This is a schematic diagram of the three-dimensional structure of a fully planar six-dimensional force sensor according to the present invention.

[0024] Figure 3 This is a bridge diagram of a strain gauge assembly for a fully planar six-dimensional force sensor according to the present invention.

[0025] Figure 4 for Figure 3 The six Wheatstone full-bridge circuits in the circuit include Figure 4 (a)-(f) are the full-bridge circuits of the first to sixth groups, respectively.

[0026] Figure 5 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 1 of the present invention when a stress of 500N Fx is applied.

[0027] Figure 6 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 1 of the present invention when a stress of 500N Fy is applied.

[0028] Figure 7 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 1 of the present invention when a stress of 500N Fz is applied.

[0029] Figure 8 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 1 of the present invention when a stress of magnitude Mx of 20 Nm is applied.

[0030] Figure 9 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 1 of the present invention when a stress of 20 Nm My is applied.

[0031] Figure 10 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 1 of the present invention when a stress of magnitude Mz of 20 Nm is applied.

[0032] Figure 11 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 2 of the present invention when a force of 25 N Fx is applied.

[0033] Figure 12 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 2 of the present invention when a stress of 25N Fy is applied.

[0034] Figure 13 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 2 of the present invention when a stress of 25N Fz is applied.

[0035] Figure 14 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 2 of the present invention when a stress of 0.5N Mx is applied.

[0036] Figure 15 The stress change and bridge output diagram of a 0.5N My applied to the full-planar six-dimensional force sensor in Embodiment 2 of the present invention.

[0037] Figure 16 The diagram shows the stress change and bridge output of the full-planar six-dimensional force sensor in Embodiment 2 of the present invention when a stress of magnitude 0.5N Mz is applied.

[0038] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein 1-Central loading platform, 2-Fixed platform, 3-Radial beam, 4-Circumferential beam, 5-Strain gauge, 6-Groove, 7-Threaded hole. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0040] In this embodiment, it should be understood that the terms "middle," "upper," "lower," "top," "right side," "left end," "above," "back," "center," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0041] In this embodiment, the thickness of the radial beam or circumferential beam is the narrower dimension in the thickness direction of the sensor, and the width of the radial beam or circumferential beam is as follows: Figure 1 The sensor has a narrower dimension in its top view.

[0042] like Figure 1 , Figure 2 The image shows an example of a planar six-dimensional force sensor of the present invention, which includes an elastic body and a strain gauge 5.

[0043] The elastic body includes a fixed platform 1, a central loading platform 2, eight radial beams 3 and four circumferential beams 4, and the fixed platform 1, the central loading platform 2, the radial beams 3 and the circumferential beams 4 are arranged on the same central plane in the thickness direction, and the overall structure is a fully planar symmetrical structure.

[0044] The fixed platform 1 is ring-shaped, and the central loading platform 2 is located inside the fixed platform 1. Eight radial beams 3 are evenly distributed radially from the fixed platform 1 towards the central loading platform 2. Among the eight radial beams, two pairs of radial beams that are symmetrical form a group of radial beams. The two groups of radial beams that are perpendicular to each other are the Fx-axis radial beams and the Fy-axis radial beams, respectively. The two groups of radial beams located between the Fx-axis radial beams and the Fy-axis radial beams are the Mz-axis radial beams and the Fz-axis radial beams, respectively.

[0045] Four circumferential beams 4 are matched one-to-one with four radial beams 3 of the Fx-axis and Fy-axis radial beams, and the circumferential beams 4 are perpendicularly bisected by the radial beams 3, so that the eight endpoints of the four circumferential beams are connected sequentially to form a fully symmetrical octagon within the fixed platform. Among them, the circumferential beam perpendicular to the Fx-axis radial beam is the My-axis circumferential beam, and the circumferential beam perpendicular to the Fy-axis radial beam is the Mx-axis circumferential beam.

[0046] There are 6 groups of strain gauges, which are respectively arranged on the radial beams of the Fx axis, Fy axis, Mz axis, Fz axis, My axis, and Mx axis. Each group of strain gauges forms an independent full-bridge circuit.

[0047] In some embodiments, a support beam is provided between the adjacent My axis circumferential beam and Mx axis circumferential beam, so that the four circumferential beams and the four support beams are connected end to end to form a fully symmetrical octagonal structure inscribed in the fixed platform.

[0048] In some embodiments, strain gauges on the Fx-axis radial beam, Fy-axis radial beam, Mz-axis radial beam, and Fz-axis radial beam are all arranged on two symmetrical radial beams, and the strain gauges on the same radial beam are symmetrically arranged on the upper and lower surfaces in the thickness direction; strain gauges on the My-axis circumferential beam and Mx-axis circumferential beam are all arranged on two symmetrical circumferential beams, the strain gauges on all circumferential beams are arranged on the same surface in the thickness direction, and the strain gauges on the same circumferential beam are symmetrically arranged based on the extension line of the radial beam.

[0049] For example, when there are 4 strain gauges on the Fz-axis radial beam, the 4 strain gauges are respectively placed on the upper and lower surfaces of the two symmetrical radial beams in the thickness direction, and the strain gauges are equidistant from the central loading platform. When there are 4 strain gauges on the Mz-axis radial beam, the 4 strain gauges are respectively placed on the same surface of the two symmetrical radial beams in the thickness direction, and the strain gauges on the same radial beam are symmetrically arranged based on the centerline of the radial beam. Or, when there are 8 strain gauges on the Mz-axis radial beam, the 8 strain gauges are respectively placed on the upper and lower surfaces of the two symmetrical radial beams in the thickness direction, and the strain gauges on the same radial beam are symmetrically arranged based on the centerline of the radial beam.

[0050] In some implementations, the radial beam widths of the Fx-axis radial beam and the Fy-axis radial beam are denoted as a, the radial beam widths of the Mz-axis radial beam and the Fz-axis radial beam are denoted as b, and the circumferential beam width is denoted as c, where 1.5a = b = c.

[0051] In some embodiments, the strain gauge of the present invention is a silicon strain gauge, which is mounted on an elastomer using a full-planar process. This reduces the difficulty of wire bonding, minimizes the size of the patch, and lowers the difficulty of mechanical assembly. At the same time, because silicon strain gauges are significantly superior to metal strain gauges in terms of sensitivity, stability, signal-to-noise ratio, and dynamic characteristics, the sensors manufactured have advantages such as high sensitivity and high stability.

[0052] In some implementations, the outer diameter of the fixed platform is 17-85mm, the thickness of the fixed platform is 5-20mm, the radial beam and the circumferential beam have the same thickness, and the thickness of the radial beam and the circumferential beam does not exceed the combined thickness of the radial beam and the circumferential beam. These preferred parameters and dimensions of the sensor are suitable for various application scenarios, and the specific dimensions can be modified according to different scenarios based on this structure.

[0053] In some implementations, the fixed platform center loading platform, radial beam, and circumferential beam are all integrally formed structures, which are simple in structure and easy to process.

[0054] In some implementations, chamfers are provided at the connections between the fixed platform and the beam, the circumferential beam and the radial beam, and the beam and the central loading platform, effectively avoiding stress concentration.

[0055] In some embodiments, recessed grooves are provided on both the left and right sides of the strain gauge along the radial beams of the Fx and Fy axes, so that the strain is concentrated in the measured area and the sensitivity in that direction is increased.

[0056] In some implementations, a gap is left between the circumferential beam and the fixed platform as a limiting hole, which serves as an overload protection structure, enabling the sensor to have a large load-bearing capacity.

[0057] This invention exemplifies a fully planar six-dimensional force sensor, specifically comprising 24 strain gauges bonded to the upper and lower surfaces of 12 beams (8 radial beams and 4 circumferential beams). When a force or torque is applied by the central loading platform, the strain gauges and the 12 beams deform together, causing a change in the resistance of the strain gauges. Figure 3 and Figure 4 Each group of strain gauges forms an independent Wheatstone full-bridge circuit, totaling six groups of full-bridge circuits. The voltages of the four strain gauges and four bridge arms in the coupling direction bridge circuit cancel each other out, achieving structural self-decoupling. The full-bridge circuits are connected to the input terminals of the signal acquisition module, and the output terminals of the signal acquisition module are connected to the terminal.

[0058] Four strain gauges, R1, R2, R3, and R4, form the first full-bridge circuit. When the sensor is subjected to a force in the X direction, the radial beam in the X direction will undergo significant deformation. Therefore, the first full-bridge circuit is used to measure the magnitude of the force FX in the X direction. Four strain gauges, R5, R6, R7, and R8, form the second full-bridge circuit. When the sensor is subjected to a force in the Y direction, the radial beam in the Y direction will undergo significant deformation. Therefore, the second full-bridge circuit is used to measure the magnitude of the force FY in the Y direction. Four strain gauges, R9, R10, R11, and R12, form the third full-bridge circuit. When the sensor is subjected to a force in the Z direction, the radial beam at a 45° angle will undergo significant deformation. Therefore, the third full-bridge circuit is used to measure the magnitude of the force FZ in the Z direction. Four strain gauges, R13, R14, R15, and R16, form the fourth full-bridge circuit. When the sensor is subjected to a torque in the X direction, the circumferential beam parallel to the Y direction will undergo significant deformation. Therefore, the fourth full-bridge circuit is used to measure the magnitude of the torque MX in the X direction. The four strain gauges R17, R18, R19, and R20 form the fifth full-bridge circuit. When the sensor is subjected to a torque in the Y direction, the circumferential beam parallel to the X direction will undergo significant deformation. Therefore, the fifth full-bridge circuit is used to measure the magnitude of the torque MY in the Y direction. The four strain gauges R21, R22, R23, and R24 form the sixth full-bridge circuit. When the sensor is subjected to a torque in the Z direction, the radial beam at a 45° angle will undergo significant deformation. Therefore, the sixth full-bridge circuit is used to measure the magnitude of the torque MZ in the Z direction.

[0059] The present invention will now be described in detail with reference to the accompanying drawings.

[0060] Example 1 provides a relatively loose six-dimensional force sensor with a diameter of 80mm and a thickness of 20mm, which can be used in fields such as humanoid robot ankles and small industrial robots.

[0061] use Figure 3 and Figure 4 In the bridge configuration, stresses of 500 N Fx / Fy / Fz and 20 Nm Mx / My / Mz were applied sequentially. The simulated stress changes and bridge outputs are shown in [reference needed]. Figure 5-10 The calculation results are shown in Tables 1 to 6.

[0062] Table 1: Correspondence Figure 5 Calculation results

[0063] Table 2: Correspondence Figure 6 Calculation results

[0064] Table 3: Correspondence Figure 7 Calculation results

[0065] Table 4: Correspondence Figure 8 Calculation results

[0066] Table 5: Correspondence Figure 9 Calculation results

[0067] Table 6: Correspondence Figure 10 Calculation results

[0068] Example 2 provides a compact six-dimensional force sensor, such as... Figure 1 As shown, it has a diameter of 17mm and a thickness of 5mm, and can be used in fields such as humanoid robot fingers, medical surgery, and scientific research.

[0069] use Figure 3 and Figure 4 The bridge configuration in the simulation involves sequentially applying stresses of 25 N (Fx / Fy / Fz) and 0.5 Nm (Mx / My / Mz). The simulated stress changes and bridge outputs are shown in [reference needed]. Figures 11-16 The calculation results are shown in Tables 7 to 12.

[0070] Table 7: Corresponding Figure 11 Calculation results

[0071] Table 8: Correspondence Figure 12 Calculation results

[0072] Table 9: Correspondence Figure 13 Calculation results

[0073] Table 10: Corresponding Figure 14 Calculation results

[0074] Table 11: Correspondence Figure 15 Calculation results

[0075] Table 12: Correspondence Figure 16 Calculation results

[0076] In the embodiments of the present invention, the data in Tables 1 to 12 show that the crosstalk of the two six-dimensional force sensors designed in Embodiment 1 and Embodiment 2 is less than 1%FS, and they have the advantages of high sensitivity, low crosstalk and excellent performance.

[0077] This embodiment and the accompanying drawings only show one method of attaching strain gauges for decoupling. The method of attaching strain gauges can be selected according to the actual needs of decoupling, and all of them are within the protection scope of this patent.

[0078] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of protection of this invention and its equivalents, this invention also intends to include these modifications and variations. The above-described embodiments are merely preferred embodiments given to fully illustrate this invention, and their scope of protection is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this invention are all within the scope of protection of this invention.

Claims

1. A fully planar six-dimensional force sensor, characterized in that, Including elastomers and strain gauges; The elastic body includes a fixed platform, a central loading platform, eight radial beams and four circumferential beams, and the fixed platform, the central loading platform, the radial beams and the circumferential beams are arranged on the same central plane in the thickness direction; The central loading platform is placed inside the fixed platform, and the eight radial beams are evenly spaced along the circumference between the central loading platform and the fixed platform; wherein, two pairs of radial beams that are symmetrical among the eight radial beams form a group of radial beams, two groups of radial beams that are perpendicular to each other are the Fx-axis radial beam and the Fy-axis radial beam, and the two groups of radial beams that are located between the Fx-axis radial beam and the Fy-axis radial beam are the Mz-axis radial beam and the Fz-axis radial beam, respectively. The four circumferential beams are matched one-to-one with four radial beams of the Fx-axis and Fy-axis radial beams, and the circumferential beams are perpendicularly bisected by the radial beams, so that the eight endpoints of the four circumferential beams are connected sequentially to form a fully symmetrical octagon within the fixed platform; wherein, the circumferential beam perpendicular to the Fx-axis radial beam is the My-axis circumferential beam, and the circumferential beam perpendicular to the Fy-axis radial beam is the Mx-axis circumferential beam; The strain gauges are arranged in 6 groups, respectively on the radial beam of the Fx axis, the radial beam of the Fy axis, the radial beam of the Mz axis, the radial beam of the Fz axis, the circumferential beam of the My axis, and the circumferential beam of the Mx axis. Each group of strain gauges forms an independent full-bridge circuit.

2. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, A supporting beam is provided between the adjacent My axis circumferential beam and the Mx axis circumferential beam, so that the four circumferential beams and the four supporting beams are connected end to end to form a fully symmetrical octagonal structure inscribed in the fixed platform.

3. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, The strain gauges on the Fx-axis radial beam, the Fy-axis radial beam, the Mz-axis radial beam, and the Fz-axis radial beam are all arranged on two symmetrical radial beams, and the strain gauges on the same radial beam are symmetrically arranged on the upper and lower surfaces in the thickness direction; the strain gauges on the My-axis circumferential beam and the Mx-axis circumferential beam are all arranged on two symmetrical circumferential beams, and the strain gauges on all the circumferential beams are arranged on the same surface in the thickness direction, and the strain gauges on the same circumferential beam are symmetrically arranged based on the extension line of the radial beam.

4. The all-planar six-dimensional force sensor as described in claim 3, characterized in that, There are 4 strain gauges on both the Fx-axis radial beam and the Fy-axis radial beam; there are 4 or 8 strain gauges on the Mz-axis radial beam, and 4 strain gauges on the Fz-axis radial beam; there are 4 strain gauges on both the My-axis circumferential beam and the Mx-axis circumferential beam.

5. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, Let a be the radial beam width of the Fx-axis radial beam and the Fy-axis radial beam, b be the radial beam width of the Mz-axis radial beam and the Fz-axis radial beam, and c be the width of the circumferential beam, where 1.5a = b = c.

6. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, The strain gauge is a silicon strain gauge.

7. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, The outer diameter of the fixed platform is 17-85mm; the thickness of the fixed platform is 5-20mm; the radial beam and the circumferential beam have the same thickness, and the thickness of the radial beam and the circumferential beam does not exceed the thickness of the fixed platform and the central loading platform.

8. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, The connection points between the fixed platform and the circumferential beam, the connection points between the circumferential beam and the radial beam, and the connection points between the central loading platform and the radial beam are all chamfered.

9. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, The strain gauges on the Fx-axis radial beam and the Fy-axis radial beam are respectively provided with recessed grooves on their left and right sides.

10. The all-planar six-dimensional force sensor as described in claim 1, characterized in that, The fixed platform is provided with 8 equidistant threaded holes, and the central loading platform is provided with 4 equidistant threaded holes. The center of each equidistant threaded hole is located on the extension line of the radial beam.

Images