Miniature six-dimensional force sensor for humanoid robot

Abstract

The invention discloses a miniature six-dimensional force sensor for a humanoid robot. The miniature six-dimensional force sensor comprises an elastic body which is integrally disc-shaped, and an upper cover plate and a lower cover plate which are arranged at the upper end and the lower end of the elastic body; the elastic body comprises an elastic body hub, a stress table and four strain beams, and the cross section of each strain beam is rectangular; the stress table is hollow and is arranged at the central position of the elastomer hub, the four strain beams are uniformly distributed between the stress table and the elastomer hub, one end of each strain beam is connected with the elastomer hub, and the other end of each strain beam is connected with the stress table; the elastomer hub is provided with a cable outlet. A plurality of strain gauges are adhered to the four strain beams to form six Wheatstone bridges for respectively measuring forces and moments in six directions of Fx, Fy, Fz, Tx, Ty and Tz. The miniature six-dimensional force sensor has the advantages that the thickness of the sensor is very small, the thickness is only 9.2 mm, the diameter is 45 mm, and the miniature six-dimensional force sensor is suitable for the humanoid robot industry.

Description

Technical Field

[0001] The present invention belongs to the field of sensor measurement, and is based on the resistive strain principle. Specifically, it is a micro six-axis force sensor for humanoid robots, which is used in the humanoid robot industry. Background Art

[0002] The six-axis force sensor is the core component for humanoid robots to achieve high-precision force control and dynamic interaction. It is commonly used in the hand or wrist to detect the force and torque of the grasped object in real time and achieve adaptive grasping. Although limited by cost and technical complexity, with the progress of material innovation and AI algorithms, it will develop towards a more intelligent and flexible direction in the future, promoting the large-scale application of humanoid robots in the industrial and service fields. In order to adapt to the rapid development of humanoid robots, it is imperative to develop a micro six-axis force sensor suitable for humanoid robots, especially as thin as possible. Summary of the Invention

[0003] The purpose of the present invention is to propose a micro six-axis force sensor for humanoid robots. According to the needs of the development of humanoid robots, a micro six-axis force sensor adapted to humanoid robots is designed, especially as thin as possible.

[0004] The technical methods adopted are as follows: A micro six-axis force sensor for humanoid robots includes an elastic body with an overall disc shape, an upper cover plate and a lower cover plate arranged at the upper and lower ends of the elastic body; the elastic body includes an elastic body hub, a force-receiving platform and four strain beams, and the cross-section of the strain beam is rectangular; the force-receiving platform is hollow and is placed at the central position of the elastic body hub. The four strain beams are evenly arranged between the force-receiving platform and the elastic body hub, and one end of the strain beam is connected to the elastic body hub and the other end is connected to the force-receiving platform; a cable outlet is arranged on the elastic body hub; multiple strain gauges are pasted on the four strain beams to form six Wheatstone bridges, which respectively measure the forces and torques in the six directions of Fx, Fy, Fz, Tx, Ty, and Tz.

[0005] For further optimization of the technical solution of the present invention, the upper end surface of the force-receiving platform is 1.7 mm higher than the upper end surface of the elastic body hub, and the lower end surface of the force-receiving platform is 1.2 mm lower than the lower end surface of the elastic body hub, leaving a certain safety space to ensure the measurement accuracy of the six directions of the sensor.

[0006] For further optimization of the technical solution of the present invention, the thickness of the micro six-axis force sensor is 9.2 mm and the diameter is 45 mm.

[0007] For further optimization of the technical solution of the present invention, 28 strain gauges are pasted on the four strain beams, and are respectively pasted on the four surfaces of the four strain beams. On the upper, lower, left, and right sides of the strain beam, according to the relevant principles in mechanics of materials, the 28 strain gauges are pasted at certain positions on the strain beam, which theoretically ensures that structural decoupling can be achieved in six directions.

[0008] For further optimization of the technical solution of the present invention, the 28 strain gauges are respectively R1~R28. Among them, R1~R4 form a full bridge to measure Tx, R5~R8 form a full bridge to measure Ty, R9~R12 form a full bridge to measure Tz, R13~R16 form a full bridge to measure Fx, R17~R20 form a full bridge to measure Fy, and R21~R28 form a full bridge to measure Fz. Only 4 strain gauges are pasted for other bridge circuits, while 8 strain gauges are pasted in the Fz direction. The reason for pasting 8 strain gauges in the Fz direction is to reduce the measurement error caused by the bending moment in the Tx or Ty direction to Fz, and ensure the measurement accuracy of Fz during eccentric loading.

[0009] For further optimization of the technical solution of the present invention, the material of the elastomer is stainless steel. The stainless steel selected in the present invention is: 17-4 PH. After a certain heat treatment process, this stainless steel has a high yield strength and enhances the overload capacity of the sensor.

[0010] For further optimization of the technical solution of the present invention, the upper cover plate and the lower cover plate are respectively embedded in the grooves on the upper and lower end faces of the elastomer and fixed, and sealant is applied around; ensuring that the protection level of the sensor reaches IP65.

[0011] For further optimization of the technical solution of the present invention, a wire pressing block is provided at the inner wall of the elastomer hub at the cable outlet, and a cable groove is provided on the wire pressing block, and the cable groove communicates with the cable outlet.

[0012] For further optimization of the technical solution of the present invention, the cable exits from the cable outlet, and sealant is applied to the cable outlet, which also ensures that the protection level of the sensor reaches IP65.

[0013] For further optimization of the technical solution of the present invention, the micro six-axis force sensor is of analog output.

[0014] For further optimization of the technical solution of the present invention.

[0015] The beneficial effects of the present invention compared with the prior art: 1. For the micro six-axis force sensor for humanoid robots of the present invention, the most prominent advantage of the micro six-axis force sensor is that the thickness of the sensor is very small, only 9.2 mm in thickness and 45 mm in diameter, which is suitable for the humanoid robot industry.

[0016] 2. For the micro six - dimensional force sensor of the humanoid robot in the present invention, the elastomer is the core component of the sensor. Due to the small space volume, a simple 4 - beam structure is adopted.

[0017] 3. For the micro six - dimensional force sensor of the humanoid robot in the present invention, after performing modal analysis on the elastomer through ANSYS Workbench, the natural frequency of the elastomer is 12845 Hz, so it has good dynamic performance.

[0018] 4. For the micro six - dimensional force sensor of the humanoid robot in the present invention, after calibration, the micro six - dimensional force sensor involved in the present invention has excellent performance, small coupling, and an overload exceeding 200%.

[0019] 5. The new micro six - dimensional force sensor for humanoid robots in the present invention has the advantages of small volume, light weight, good dynamic performance, high output sensitivity, high measurement accuracy, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a three - dimensional schematic diagram of the front of a micro six - dimensional force sensor for a humanoid robot in this embodiment; Figure 2 is a three - dimensional schematic diagram of the back of a micro six - dimensional force sensor for a humanoid robot in this embodiment; Figure 3 is a three - dimensional schematic diagram of the elastomer; Figure 4 is the bridge - forming schematic diagram of the micro six - dimensional force sensor for a humanoid robot in this embodiment ( Figure 4a is the upper part diagram based on the broken line a - a, Figure 4b is the middle part diagram based on the broken lines a - a and b - b, Figure 4c is the upper part diagram based on the broken line b - b); Figure 5 is the top view after pasting the strain gauges on the elastomer in this embodiment; Figure 6 is Figure 5 the A - A sectional view of Figure 7 is Figure 5 the B - B sectional view of Figure 8 is Figure 5 the C - C sectional view of Figure 9 is Figure 5 the D - D sectional view of Figure 10 is the equivalent stress nephogram calculated by ANSYS Workbench when the load Fx = 1200 N is applied to the micro six - dimensional force sensor for a humanoid robot in this embodiment; Figure 11It is the displacement nephogram calculated by ANSYS Workbench when the load Fx = 1200N is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 12 It is the equivalent stress nephogram calculated by ANSYS Workbench when the load Fy = 1200N is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 13 It is the displacement nephogram calculated by ANSYS Workbench when the load Fy = 1200N is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 14 It is the equivalent stress nephogram calculated by ANSYS Workbench when the load Fz = 2000N is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 15 It is the displacement nephogram calculated by ANSYS Workbench when the load Fz = 2000N is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 16 It is the equivalent stress nephogram calculated by ANSYS Workbench when the load Tx = 27 Nm is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 17 It is the displacement nephogram calculated by ANSYS Workbench when the load Tx = 27 Nm is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 18 It is the equivalent stress nephogram calculated by ANSYS Workbench when the load Ty = 27 Nm is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 19 It is the displacement nephogram calculated by ANSYS Workbench when the load Ty = 27 Nm is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 20 It is the equivalent stress nephogram calculated by ANSYS Workbench when the load Tz = 27 Nm is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 21 It is the displacement nephogram calculated by ANSYS Workbench when the load Tz = 27 Nm is applied to the micro six - dimensional force sensor of the humanoid robot in this embodiment; Figure 22 It is the structural schematic diagram of the strain gauge; Among them, 1 - upper cover plate, 2 - elastic body, 3 - lower cover plate, 4 - first strain beam, 5 - second strain beam, 6 - third strain beam, 7 - fourth strain beam, R1~R28 - strain gauges. Detailed implementation manners

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying Figure 1 - accompanying Figure 22 drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] As Figure 1 and 2 shown, this embodiment is a micro six-axis force sensor for humanoid robots, which is used in the humanoid robot industry. This micro six-axis force sensor for humanoid robots is based on the principle of resistance strain.

[0023] A micro six-axis force sensor for humanoid robots includes an upper cover plate 1, an elastic body 2 and a lower cover plate 3, three components.

[0024] The most prominent advantages of the micro six-axis force sensor in this embodiment are as follows: the thickness of the sensor is very small, only 9.2 mm, and the diameter is 45 mm, which is suitable for the humanoid robot industry; the second is that the elastic body 2 is the core component of the sensor. Due to the small space volume, a simple 4-beam structure is adopted; the third is that through modal analysis of the elastic body by ANSYS Workbench, the natural frequency of the elastic body is 12,845 Hz, so it has good dynamic performance; the fourth is that after calibration, the micro six-axis force sensor in this embodiment has excellent performance, small coupling, and overload exceeding 200%. This micro six-axis force sensor has the advantages of small volume, light weight, good dynamic performance, high measurement accuracy, etc.

[0025] As Figure 3 shown, the three-dimensional model of the core component elastic body 2. The upper cover plate 1 is connected to the elastic body 2 with screws, and the lower cover plate 3 is connected to the elastic body 2 with screws. The periphery is sealed with glue, and the cable passes out through the wire outlet for glue sealing to ensure that the protection level of the sensor reaches IP65.

[0026] As Figure 1 and 2 shown, grooves are respectively provided on the upper and lower end faces of the elastic body 2. The upper cover plate 1 and the lower cover plate 3 are respectively embedded in the grooves and fixed with bolts, and the periphery is sealed with sealant.

[0027] As Figure 3As shown in the figure, the elastomer 2 includes an elastomer hub, a force-bearing platform, and four strain beams. The cross-section of the strain beam is rectangular. The force-bearing platform is hollow and is placed at the center of the elastomer hub. The four strain beams are evenly arranged between the force-bearing platform and the elastomer hub. One end of the strain beam is connected to the elastomer hub, and the other end is connected to the force-bearing platform. A cable outlet 21 is provided on the elastomer hub.

[0028] In this embodiment, the upper end face of the force-bearing platform of the elastomer 2 is 1.7 mm higher than the upper end face of the elastomer hub, and the lower end face of the force-bearing platform is 1.2 mm lower than the lower end face of the elastomer hub.

[0029] In this embodiment, the material of the elastomer 2 is stainless steel, which is 17-4PH, quenched and tempered, with a hardness of HRC38-40 and a yield strength of not less than 1300 Mpa. Sensors all have requirements for overload capacity. When the full-scale load is Tx / Ty = 27 Nm, the equivalent stress is 513 Mpa. In order to meet the sensor overload capacity of ≮200%.

[0030] In this embodiment, as Figure 3 shown in the figure, a wire pressing block 22 is provided at the inner wall of the elastomer hub of the elastomer 2 at the cable outlet 21. A cable groove is provided on the wire pressing block 22. The cable groove is communicated with the cable outlet 21. The cable in the elastomer 2 is placed on the cable groove on the wire pressing block 22. Specifically: A wire pressing block 22 is provided at the inner wall of the elastomer hub at the cable outlet 21. A wire pressing plate is provided on the wire pressing block 22. The wire pressing plate is fixed with two M1.6 screws to fix the cable in the cable groove and prevent the cable from moving. The cable exits from the cable outlet 21, and the cable is first fixed by the wire pressing block 22 and the wire pressing plate, and then sealed with sealant.

[0031] As Figure 5 shown in the figure, 4 strain beams are symmetrically provided on the elastomer 2, namely the first strain beam 4, the second strain beam 5, the third strain beam 6, and the fourth strain beam 7. One end of each strain beam is connected to the middle force-bearing platform, and one end is connected to the elastomer hub.

[0032] As Figure 5 shown in the figure, a total of 28 strain gauges are pasted on the four strain beams, which are pasted on the four surfaces of the four strain beams respectively to form six Wheatstone bridges to measure the forces and torques in the six directions of Fx, Fy, Fz, Tx, Ty, and Tz respectively.

[0033] As shown in Figure 4, the six measurement directions of Fx, Fy, Fz, Tx, Ty, and Tz adopt a full-bridge measurement scheme. Among them, bridge circuit one measures Tx, bridge circuit two measures Ty, bridge circuit three measures Tz, bridge circuit four measures Fx, bridge circuit five measures Fy, and bridge circuit six measures Fz.

[0034] As Figure 5As shown, the 28 strain gauges are R1 to R28 respectively. Among them, R1 to R4 form a full bridge to measure Tx, R5 to R8 form a full bridge to measure Ty, R9 to R12 form a full bridge to measure Tz, R13 to R16 form a full bridge to measure Fx, R17 to R20 form a full bridge to measure Fy, and R21 to R28 form a full bridge to measure Fz.

[0035] As Figure 22 shown, in this embodiment, the strain gauges are off-the-shelf components. There are 4 positioning marks on the strain gauges. Among them, positioning marks a and b are for positioning the center line, positioning marks c and d are for positioning the wire grid, and e and f are two solder joints.

[0036] As shown in Figure 4, bridge circuit one measures Tx, bridge circuit two measures Ty, bridge circuit three measures Tz, bridge circuit four measures Fx, bridge circuit five measures Fy, and bridge circuit six measures Fz. These six bridge circuits are in parallel. In the bridge circuit diagram of Figure 4, R1 - R28 represent strain gauges, and R - represents the resistance value of the selected strain gauge, with a resistance value of 350Ω.

[0037] For the micro six - dimensional force sensor used in the humanoid robot in this embodiment, the measurement ranges are: Fx = Fy = 1200N; Fz = 2000N; Tx = Ty = Tz = 27 Nm.

[0038] For the micro six - dimensional force sensor used in the humanoid robot in this embodiment, the pasting positions of the 28 strain gauges are as follows: As shown in Figure 4, define four strain beams as the first strain beam 4, the second strain beam 5, the third strain beam 6, and the fourth strain beam 7. The first strain beam 4 and the third strain beam 6 are on the same straight line, and the second strain beam 5 and the fourth strain beam 7 are on the same straight line.

[0039] On the left and right sides of the first strain beam 4, strain gauges R13 and R14 are pasted near one end of the elastomer hub. Strain gauges R13 and R14 are symmetrically arranged about the Y - axis, and the solder joints of strain gauges R13 and R14 face the direction of the force - receiving platform, that is, the - Y direction; on the left and right sides of the third strain beam 6, strain gauges R15 and R16 are pasted near one end of the elastomer hub. Similarly, strain gauges R15 and R16 are symmetrically arranged about the Y - axis, and the solder joints of strain gauges R15 and R16 face the direction of the force - receiving platform, that is, the + Y direction; strain gauges R14 and R15 are symmetrically arranged about the X - axis, and similarly, strain gauges R13 and R16 are symmetrically arranged about the X - axis. After calculation by ANSYS Workbench, the distance L1 between the wire grid positioning marks of these two strain gauges R14 and R15 is 31.2mm. Similarly, the distance between the wire grid positioning marks of these two strain gauges R13 and R16 is 31.2mm. As Figure 6 、 7 and Figure 8 show.

[0040] On the left and right sides of the first strain beam 4, strain gauges R9 and R10 are pasted at one end close to the force-receiving platform. The strain gauges R9 and R10 are symmetrically arranged about the Y-axis, and the solder joints of the strain gauges R9 and R10 face away from the force-receiving platform, that is, in the +Y direction; on the left and right sides of the third strain beam 6, strain gauges R12 and R11 are pasted at one end close to the force-receiving platform. Similarly, the strain gauges R12 and R11 are symmetrically arranged about the Y-axis, and the solder joints of the strain gauges R12 and R11 face away from the force-receiving platform, that is, in the -Y direction; the strain gauges R10 and R12 are symmetrically arranged about the X-axis, and similarly, the strain gauges R9 and R11 are symmetrically arranged about the X-axis; after calculation by ANSYS Workbench, the distance L2 between the grid positioning marks of the two strain gauges R10 and R12 is 23.8 mm. Similarly, the distance between the grid positioning marks of the two strain gauges R9 and R11 is 23.8 mm. As Figure 5 , 6 and shown in 7.

[0041] On the upper and lower surfaces of the first strain beam 4, strain gauges R1 and R2 are pasted at one end close to the elastomer hub. The strain gauges R1 and R2 are symmetrically arranged up and down, and the solder joints of the strain gauges R1 and R2 face the force-receiving platform direction, that is, in the -Y direction; on the upper and lower surfaces of the third strain beam 6, strain gauges R3 and R4 are pasted at one end close to the elastomer hub. Similarly, the strain gauges R3 and R4 are symmetrically arranged up and down, and the solder joints of the strain gauges R3 and R4 face the force-receiving platform direction, that is, in the +Y direction; the strain gauges R2 and R4 are symmetrically arranged about the X-axis, and similarly, the strain gauges R1 and R3 are symmetrically arranged about the X-axis; after calculation by ANSYS Workbench, the distance between the grid positioning marks of the two strain gauges R2 and R4 is 31.2 mm. Similarly, the distance between the grid positioning marks of the two strain gauges R1 and R3 is 31.2 mm. As Figure 5 , 6 and shown in 7.

[0042] On the upper and lower surfaces of the first strain beam 4, strain gauges R21 and R22 are pasted at one end close to the force-receiving platform. The strain gauges R21 and R22 are symmetrically arranged up and down, and the solder joints of the strain gauges R21 and R22 face away from the force-receiving platform direction, that is, in the +Y direction; on the upper and lower surfaces of the third strain beam 6, strain gauges R23 and R24 are pasted at one end close to the force-receiving platform. Similarly, the strain gauges R23 and R24 are symmetrically arranged up and down, and the solder joints of the strain gauges R23 and R24 face away from the force-receiving platform direction, that is, in the -Y direction; the strain gauges R21 and R24 are symmetrically arranged about the X-axis, and similarly, the strain gauges R22 and R23 are symmetrically arranged about the X-axis; after calculation by ANSYS Workbench, the distance between the grid positioning marks of the two strain gauges R21 and R24 is 23.8 mm. Similarly, the distance between the grid positioning marks of the two strain gauges R22 and R23 is 23.8 mm. As Figure 5 , 6 and shown in 7.

[0043] On the left and right sides of the second strain beam 5, strain gauges R17 and R18 are pasted near one end of the elastomeric hub. The strain gauges R17 and R18 are symmetrically arranged about the X-axis, and the solder joints of the strain gauges R17 and R18 face the direction of the force-receiving platform, that is, the -X direction. On the left and right sides of the fourth strain beam 7, strain gauges R19 and R20 are pasted near one end of the elastomeric hub. Similarly, the strain gauges R19 and R20 are symmetrically arranged about the X-axis, and the solder joints of the strain gauges R19 and R20 face the direction of the force-receiving platform, that is, the +X direction. The strain gauges R18 and R19 are symmetrically arranged about the Y-axis, and similarly, the strain gauges R17 and R20 are symmetrically arranged about the Y-axis. After calculation by ANSYS Workbench, the distance L3 between the grid positioning marks of the two strain gauges R18 and R19 is 31.2 mm. Similarly, the distance between the grid positioning marks of the two strain gauges R17 and R20 is 31.2 mm. As Figure 5 、 8 and 9 show.

[0044] On the upper and lower surfaces of the second strain beam 5, strain gauges R7 and R8 are pasted near one end of the elastomeric hub. The strain gauges R7 and R8 are symmetrically arranged vertically, and the solder joints of the strain gauges R7 and R8 face the direction of the force-receiving platform, that is, the -X direction. On the upper and lower surfaces of the fourth strain beam 7, strain gauges R5 and R6 are pasted near one end of the elastomeric hub. Similarly, the strain gauges R5 and R6 are symmetrically arranged vertically, and the solder joints of the strain gauges R5 and R6 face the direction of the force-receiving platform, that is, the +X direction. The strain gauges R8 and R6 are symmetrically arranged about the Y-axis, and similarly, the strain gauges R7 and R5 are symmetrically arranged about the Y-axis. After calculation by ANSYS Workbench, the distance between the grid positioning marks of the two strain gauges R8 and R6 is 31.2 mm. Similarly, the distance between the grid positioning marks of the two strain gauges R7 and R5 is 31.2 mm. As Figure 5 、 8 and 9 show.

[0045] On the upper and lower surfaces of the second strain beam 5, strain gauges R27 and R28 are pasted near one end of the force-receiving platform. The strain gauges R27 and R28 are symmetrically arranged vertically, and the solder joints of the strain gauges R27 and R28 face away from the force-receiving platform, that is, the +X direction. On the upper and lower surfaces of the fourth strain beam 7, strain gauges R25 and R26 are pasted near one end of the force-receiving platform. Similarly, the strain gauges R25 and R26 are symmetrically arranged vertically, and the solder joints of the strain gauges R25 and R26 face away from the force-receiving platform, that is, the -X direction. The strain gauges R28 and R25 are symmetrically arranged about the Y-axis, and similarly, the strain gauges R27 and R26 are symmetrically arranged about the Y-axis. After calculation in ANSYS Workbench, the distance between the grid positioning marks of the two strain gauges R28 and R25 is 23.8 mm. Similarly, the distance between the grid positioning marks of the two strain gauges R27 and R26 is 23.8 mm. As Figure 5 、 8 and 9 show.

[0046] The micro six-axis force sensor for humanoid robots in this embodiment, as shown in Figure 6 , 7 , Figures 8 and 9, all strain gauges bonded to the sides of the four strain beams, and the distance L4 from the strain gauge positioning grid to the force-receiving platform is 5.45 mm.

[0047] The micro six-axis force sensor for humanoid robots in this embodiment has been subjected to modal analysis of the elastomer by ANSYS Workbench. The natural frequency of this micro six-axis force sensor for humanoid robots is 12,845 Hz, and it has good dynamic performance.

[0048] The specific process of using ANSYS Workbench to perform strength analysis on the elastomer is as follows: As mentioned above, the six measurement directions of Fx, Fy, Fz, Tx, Ty, and Tz adopt the measurement scheme of six Wheatstone bridges. Perform simulation calculations in ANSYS Workbench, and perform full-scale loading separately for each direction. Calculate the strength and output sensitivity when each direction is fully loaded. The material is stainless steel 17-4PH. When calculating the sensitivity of each bridge circuit below, the bridge excitation voltage is calculated according to 5V.

[0049] When loading Fx = 1200N; as shown in Figure 10 and 11 ; The first strain beam 4 and the third strain beam 6 are bent. As shown in Figure 5 , 6 and 7, strain gauges R13 and R14 are pasted on the side of the first strain beam 4, and strain gauges R15 and R16 are pasted on the side of the third strain beam 6. Among them, strain gauges R13 and R16 are subjected to tensile strain, and strain gauges R14 and R15 are subjected to compressive strain, forming bridge circuit four in Figure 4. After calculation by ANSYS Workbench, the equivalent stress is 62.212 Mpa, the deformation amount is 0.0033353 mm, the strain measured by R13 is , the strain measured by R14 is , the strain measured by R15 is , the strain measured by R16 is , then:

[0050] ——Indicates the output voltage value in the Fx direction when Fx is fully loaded; ——Indicates the sensitivity coefficient of the strain gauge. Usually, the average value is taken during calculation, and k = 2 is taken; ——Indicates the strain measured in the area where strain gauge R13 is pasted; —— represents the strain measured in the patch area of strain gauge R14; —— represents the strain measured in the patch area of strain gauge R15; —— represents the strain measured in the patch area of strain gauge R16; —— represents the excitation voltage of the bridge circuit, here taking

[0051]

[0052] Then the output sensitivity in the Fx direction:

[0053] When loading Fy = 1200N, as Figure 12 and 13 shown; The second strain beam 5 and the fourth strain beam 7 are bent, as Figure 5 , 8 and 9 shown, strain gauges R17 and R18 are pasted on the side of the second strain beam 5, and strain gauges R19 and R20 are pasted on the side of the fourth strain beam 7. Among them, strain gauges R17 and R20 are subjected to tensile strain, and strain gauges R19 and R20 are subjected to compressive strain, forming bridge circuit five in Figure 4. After calculation by ANSYS Workbench, the equivalent stress is 63.69 Mpa, the deformation amount is 0.0039524 mm, the strain measured by R17 is , the strain measured by R18 is , the strain measured by R19 is , the strain measured by R20 is , then:

[0054] —— represents the output voltage value in the Fy direction when Fy is fully loaded; —— represents the sensitivity coefficient of the strain gauge. Usually, the average value is taken during calculation, taking k = 2; —— represents the strain measured in the patch area of strain gauge R17; —— represents the strain measured in the patch area of strain gauge R18; —— represents the strain measured in the patch area of strain gauge R19; —— represents the strain measured in the patch area of strain gauge R20; —— represents the excitation voltage of the bridge circuit, and here we take

[0055] Then the output sensitivity in the Fy direction is: The sensitivity is:

[0056] When Fz = 2000N is loaded, as Figure 14 and 15 shown; All four strain beams are bent, as Figure 5 , 6 , 7, 8 and 9 shown. Strain gauges R21 and R22 are respectively pasted on the upper and lower sides of the first strain beam 4, strain gauges R24 and R23 are respectively pasted on the upper and lower sides of the third strain beam 6, strain gauges R25 and R26 are respectively pasted on the upper and lower sides of the fourth strain beam 7, and strain gauges R28 and R27 are respectively pasted on the upper and lower sides of the second strain beam 5. Among them, R21, R24, R25, R28 are subject to tensile strain, and R22, R23, R26, R27 are subject to compressive strain, forming bridge circuit six in Figure 4. After calculation by ANSYS Workbench, the equivalent stress is 238.62 Mpa, the deformation amount is 0.020561 mm, the strain measured by R21 is , the strain measured by R22 is , the strain measured by R23 is , the strain measured by R24 is , the strain measured by R25 is , the strain measured by R26 is , the strain measured by R27 is , the strain measured by R28 is , then:

[0057] —— represents the output voltage value in the Fz direction when Fz is fully loaded; —— represents the sensitivity coefficient of the strain gauge. Usually, the average value is taken during calculation, and k = 2 is taken; —— represents the strain measured in the area where the strain gauge R21 is pasted; —— represents the strain measured in the area where the strain gauge R²2 is pasted; —— represents the strain measured in the area where the strain gauge R23 is pasted; —— represents the strain measured in the area where the strain gauge R24 is pasted; —— represents the strain measured in the bonding area of strain gauge R25; —— represents the strain measured in the bonding area of strain gauge R26; —— represents the strain measured in the bonding area of strain gauge R27; —— represents the strain measured in the bonding area of strain gauge R28; —— represents the excitation voltage of the bridge circuit, here take

[0058] Then the output sensitivity in the Fz direction is:

[0059] When loading Tx = 27 Nm, as Figure 16 and 17 shown; The first strain beam 4 and the third strain beam 6 are bent, as Figure 5 , 6 and 7 shown, strain gauges R1 and R2 are pasted on the lower and upper sides of the first strain beam 4, and strain gauges R13 and R4 are pasted on the lower and upper sides of the third strain beam 6. Among them, strain gauges R1 and R4 are subjected to tensile strain, and strain gauges R2 and R3 are subjected to compressive strain, forming bridge circuit one in Figure 4. After calculation by ANSYS Workbench, the equivalent stress is 457.44 Mpa, the deformation is 0.026347 mm, the strain measured by R1 is , the strain measured by R2 is , the strain measured by R3 is , the strain measured by R4 is , then:

[0060] —— represents the output voltage value in the Tx direction when Tx is fully loaded; —— represents the sensitivity coefficient of the strain gauge. Usually, the average value is taken during calculation, take k = 2; —— represents the strain measured in the bonding area of strain gauge R1; —— represents the strain measured in the bonding area of strain gauge R2; —— represents the strain measured in the bonding area of strain gauge R3; —— represents the strain measured in the bonding area of strain gauge R4; —— represents the excitation voltage of the bridge circuit, and here we take

[0061] Then the output sensitivity in the Tx direction is:

[0062] When Ty = 27 Nm is loaded, as Figure 18 and 19 shown; The fourth strain beam 7 and the second strain beam 5 are bent, as Figure 5 、 8 and 9 shown. Strain gauges R5 and R6 are pasted on the lower and upper sides of the fourth strain beam 7, and strain gauges R7 and R8 are pasted on the lower and upper sides of the second strain beam 5. Among them, strain gauges R5 and R8 are subjected to tensile strain, and strain gauges R6 and R7 are subjected to compressive strain, forming bridge circuit two in Figure 4. After calculation by ANSYS Workbench, the equivalent stress is 513.09 Mpa, the deformation amount is 0.026721 mm, the strain measured by R5 is ,the strain measured by R6 is ,the strain measured by R7 is ,the strain measured by R8 is ,then:

[0063] —— represents the output voltage value in the Ty direction when Ty is fully loaded; —— represents the sensitivity coefficient of the strain gauge. Usually, the average value is taken during calculation, and k = 2 is taken; —— represents the strain measured in the area where strain gauge R5 is pasted; —— represents the strain measured in the area where strain gauge R6 is pasted; —— represents the strain measured in the area where strain gauge R7 is pasted; —— represents the strain measured in the area where strain gauge R8 is pasted; —— represents the excitation voltage of the bridge circuit, and here we take

[0064] Then the output sensitivity in the Ty direction is:

[0065] When Tz = 27 Nm is loaded, as Figure 20 and 21 shown; All four strain beams are bent, as Figure 5 、6 As shown in Figures 7, 8, and 9, strain gauges R9 and R10 are respectively pasted on the side surfaces of the first strain beam 4, and strain gauges R11 and R12 are respectively pasted on the side surfaces of the third strain beam 6. Among them, strain gauges R9 and R12 are subjected to tensile strain, and strain gauges R10 and R11 are subjected to compressive strain, forming bridge circuit three in Figure 4. After calculation by ANSYS Workbench, the equivalent stress is 234.71 Mpa, the deformation amount is 0.010398 mm, and the strain measured by R9 is , the strain measured by R10 is , the strain measured by R11 is , the strain measured by R12 is , then:

[0066] —— represents the output voltage value in the Tz direction when Tz is fully loaded; —— represents the sensitivity coefficient of the strain gauge, usually taking the average value during calculation, taking k = 2; —— represents the strain measured in the area where strain gauge R9 is pasted; —— represents the strain measured in the area where strain gauge R10 is pasted; —— represents the strain measured in the area where strain gauge R11 is pasted; —— represents the strain measured in the area where strain gauge R12 is pasted; —— represents the excitation voltage of the bridge circuit, here taking

[0067] Then the output sensitivity in the Ty direction is:

[0068] For the micro six - axis force sensor for humanoid robots in this embodiment, through modal analysis, it is obtained that the micro six - axis force sensor in this embodiment has excellent performance, small coupling, and an overload exceeding 200%. The micro six - axis force sensor for humanoid robots in this embodiment has the advantages of small volume, light weight, good dynamic performance, and high measurement accuracy.

[0069] The micro six - axis force sensor for humanoid robots in this embodiment is externally connected to a data collector with the model number NST2000 developed by Nanjing Shenyuansheng Intelligent Technology Co., Ltd., and communicates via UDP. The sensor is calibrated according to the "Calibration Specification for Multi - component Force Sensors" (Standard No.: JJF 1560 - 2016), and the calibration calculation results are shown in Table 1 below.

[0070] Table 1

[0071] In summary, according to the calibration data in Table 1, the miniature six-axis force sensor for humanoid robots in this embodiment has high precision and excellent performance, and is suitable for use in the robotics industry.

[0072] It is easy for those skilled in the art to understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A micro six-axis force sensor for a humanoid robot, characterized in that, It includes an elastomer (2) with an overall disc shape, an upper cover plate (1) and a lower cover plate (3) provided at the upper and lower ends of the elastomer (2); The elastomer (2) includes an elastomer hub, a force-bearing platform and four strain beams. The cross-section of the strain beam is rectangular; the force-bearing platform is hollow and is placed at the central position of the elastomer hub. The four strain beams are evenly arranged between the force-bearing platform and the elastomer hub, and one end of the strain beam is connected to the elastomer hub and the other end is connected to the force-bearing platform; a cable outlet (21) is provided on the elastomer hub; multiple strain gauges are pasted on the four strain beams to form six Wheatstone bridges to measure the forces and torques in six directions of Fx, Fy, Fz, Tx, Ty, and Tz respectively.

2. The micro six-axis force sensor for a humanoid robot according to claim 1, characterized in that, The upper end face of the force-bearing platform is 1.7 mm higher than the upper end face of the elastomer hub, and the lower end face of the force-bearing platform is 1.2 mm lower than the lower end face of the elastomer hub.

3. The miniature six-axis force sensor for a humanoid robot according to claim 1 or 2, characterized in that, The thickness of the micro six-axis force sensor is 9.2 mm and the diameter is 45 mm.

4. The miniature six-axis force sensor for a humanoid robot according to claim 1, characterized in that A total of 28 strain gauges are pasted on the four strain beams, and are respectively pasted on the four surfaces of the four strain beams.

5. The micro six-axis force sensor for humanoid robots according to claim 4, characterized in that, The 28 strain gauges are respectively R1~R28. Among them, R1~R4 form a full bridge to measure Tx, R5~R8 form a full bridge to measure Ty, R9~R12 form a full bridge to measure Tz, R13~R16 form a full bridge to measure Fx, R17~R20 form a full bridge to measure Fy, and R21~R28 form a full bridge to measure Fz.

6. The micro six-axis force sensor for humanoid robots according to claim 1, characterized in that, The material of the elastomer (2) is stainless steel.

7. The micro six-axis force sensor for a humanoid robot according to claim 1, characterized in that, The upper cover plate (1) and the lower cover plate (3) are respectively embedded in the grooves on the upper and lower end faces of the elastomer (2) and fixed, and sealant is applied around.

8. The micro six-axis force sensor for a humanoid robot according to claim 1, wherein, A wire pressing block (22) is provided at the inner wall of the elastomer hub at the cable outlet (21). A cable groove is provided on the wire pressing block (22), and the cable groove communicates with the cable outlet (21).

9. The micro six-axis force sensor for a humanoid robot according to claim 8, wherein The cable exits from the cable outlet (21), and sealant is applied to the cable outlet (21).

10. The micro six-axis force sensor for a humanoid robot according to claim 1, characterized in that, The micro six-axis force sensor has an analog output.

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