A micro-finger force three-dimensional force sensor for humanoid robots

Abstract

This invention discloses a miniature three-dimensional force sensor for humanoid robots, comprising an elastomer, a force-receiving adapter plate, a signal processing board, an upper cover plate, and a lower cover plate. The upper and lower cover plates respectively cover the upper and lower end faces of the elastomer. The outer surface of the upper cover plate is a force-receiving surface, and the force-receiving surface is hemispherical. The upper cover plate is made of a soft material. The force-receiving adapter plate is inserted into the upper cover plate and fixed to the elastomer. The signal processing board is embedded in the lower cover plate and connected to the elastomer by wires. The elastomer includes an elastomer wheel rim, a central force-receiving platform, and four strain beams. The four strain beams are evenly distributed between the central force-receiving platform and the elastomer wheel rim. A total of twelve single-crystal silicon semiconductor strain gauges are set on the four strain beams, forming three Wheatstone bridges to measure the force in the three directions Fx, Fy, and Fz respectively. Advantages: This three-dimensional force sensor is small in size, lightweight, and has high measurement resolution.

Description

Technical Field

[0001] This utility model belongs to the field of sensor measurement and is based on the principle of resistive strain. Specifically, it is a miniature three-dimensional force sensor for finger force in humanoid robots, which is used in the humanoid robot industry. Background Technology

[0002] In recent years, the robotics industry has developed explosively. Due to the rapid development of humanoid robots and their use in various industries, fingertip force sensors, as a core component of the fingertips of humanoid robots, play an extremely important role.

[0003] A fingertip force sensor is a high-precision device used to measure contact force and torque during fingertip movements or fine motor operations. It is widely used in various robotics, prosthetics, medical devices, and interactive technologies to achieve accurate force feedback and tactile perception. Classified by working principle, it is mainly divided into strain gauge, piezoresistive, capacitive, and photoelectric types; from a technological perspective, it is mainly divided into two categories: MEMS sensors and biomimetic sensors. A typical application of fingertip force sensors is robot grasping, adjusting the gripping force in real time to prevent objects from slipping or being damaged. Currently, fingertip sensors face many challenges: 1) Miniaturization and multi-axis integration: Achieving high-precision multi-dimensional force (or torque) measurement within a limited space; 2) Balance between sensitivity and range: It is necessary to detect tiny forces, such as 0.1N (or even smaller), while also being able to withstand large loads; 3) Environmental interference: Temperature drift of the sensor itself caused by temperature changes, as well as electromagnetic interference, etc.; 4) The complexity of signal processing: coupling interference between multiple dimensions of sensors, and research on decoupling algorithms; 5) Breakthrough in bionics: Research on developing touch sensors that are closer to human skin.

[0004] In conclusion, fingertip force sensors are developing towards greater intelligence, flexibility, and integration, playing a central role in future humanoid robots, intelligent prosthetics, and metaverse interaction. Utility Model Content

[0005] The purpose of this invention is to propose a miniature three-dimensional force sensor for humanoid robots. Based on the needs of humanoid robot development, a miniature three-dimensional force sensor for the tip of the humanoid robot's finger is designed to be compatible with humanoid robots.

[0006] The technical methods adopted are as follows: A miniature three-dimensional force sensor for humanoid robots, the three-dimensional force sensor being shaped like the fingertip of a finger, includes an elastomer (1), a force-receiving adapter plate (4), a signal processing board (5), an upper cover plate (2), and a lower cover plate (3). The upper cover plate (2) and the lower cover plate (3) cover the upper and lower end faces of the elastomer (1), respectively. The outer surface of the upper cover plate (2) is a force-receiving surface, and the force-receiving surface is hemispherical. The upper cover plate (2) is made of a soft material. The force-receiving adapter plate (4) is inserted into the upper cover plate (2) and fixed to the elastomer (1). The No. 5 processing board is embedded in the lower cover plate (3), and the power lines and signal lines of each bridge circuit on the elastomer (1) are welded to the corresponding solder points on the signal force measuring board. The elastomer (1) includes an elastomer wheel rim, a central force platform and four strain beams. The four strain beams are evenly distributed between the central force platform and the elastomer wheel rim, and one end of each strain beam is connected to the elastomer wheel rim, and the other end is connected to the central force platform. A total of twelve single-crystal silicon semiconductor strain gauges are set on the four strain beams to form three Wheatstone bridges to measure the forces in the three directions of Fx, Fy and Fz respectively.

[0007] A further optimization of the technical solution of this utility model is that a spherical protrusion (11) is integrally formed on the end face of one end of the elastic body rim. The purpose of the spherical protrusion design is to mimic the human finger.

[0008] In a further preferred embodiment of the present invention, the material of the upper cover plate (2) is silicone rubber, and a groove for accommodating the force-bearing adapter plate (4) is recessed at one end face along the thickness direction of the upper cover plate (2). The gap between the upper cover plate (2) and the elastic body rim is sealed with adhesive. The gap between the upper cover plate and the elastic body rim is sealed with adhesive to prevent the entry of water or other foreign objects.

[0009] In a further optimization of the technical solution of this utility model, a single-crystal silicon semiconductor strain gauge is sintered on the strain beam of the elastic body (1). The single-crystal silicon semiconductor strain gauge is sintered on the strain beam of the elastic body using glass micro-melting technology. Compared with ordinary metal strain gauges, single-crystal silicon semiconductors have two most significant characteristics: first, a high sensitivity coefficient, typically about 50 times that of ordinary metal strain gauges; and second, a smaller size.

[0010] In a further preferred embodiment of the present invention, the lower cover plate (3) is provided with a recessed groove for accommodating the signal processing board (5). The signal processing board (5) is placed in the groove and sealed with sealant to prevent water or other foreign objects from entering and to protect the electronic components inside.

[0011] In a further optimization of the technical solution of this utility model, the upper surface of the central force-bearing platform of the elastic body (1) is 0.5mm higher than the upper surface of the elastic body rim, and the lower surface of the central force-bearing platform is 0.5mm lower than the lower surface of the elastic body rim. This provides a certain safety space and ensures the accuracy of the sensor's measurements in three directions.

[0012] A further optimization of the technical solution of this utility model involves a rectangular cross-section for the strain beams, with twelve single-crystal silicon semiconductor strain gauges respectively disposed on the upper and lower surfaces of the four strain beams. This design fully considers the limitations of current glass technology, as current glass micro-melting technology can only sinter on the upper and lower surfaces of the strain beams, not on the sides.

[0013] Further optimization of the technical solution of this utility model: the single-crystal silicon semiconductor strain gauge is first sintered on the strain beam of the elastic body (1). Multiple wire binding plates are provided on the elastic body (1), all of which are welded to the irregular plate (12). The irregular plate (12) is integrally formed on the elastic body wheel rim and is located between the central force platform and the elastic body wheel rim. The aluminum wire is bound to the wire binding plate by a professional wire binding machine. The wire binding plate has corresponding lead solder joints. The corresponding solder joints on the wire binding plate are bridged by terminal blocks. After the bridge is completed, the power lines and signal lines of each bridge circuit are soldered to the corresponding solder joints on the signal processing board (5). Four core wires are led out from the signal processing board (5), namely power +, power -, signal + and signal -, and are led out through the outlet (31) opened on the end face of the lower cover plate (3). The outlet (31) is coated with sealant. The small space of the sensor elastic body is fully considered.

[0014] In a further optimization of the technical solution of this utility model, the material of the elastomer (1) is 17-4 PH stainless steel. After a certain heat treatment process, this stainless steel material has high yield strength, which enhances the overload capacity of the sensor.

[0015] Further optimization of the technical solution of this utility model involves twelve single-crystal silicon semiconductor strain gauges, namely R1~R12. Among them, R1~R4 form a full-bridge measurement Fx, R5~R8 form a full-bridge measurement Fy, and R9~R12 form a full-bridge measurement Fz. The purpose of using full-bridge in all three directions is to achieve high sensitivity and high measurement accuracy.

[0016] The advantages of this utility model compared with the prior art are as follows: 1. The present invention relates to a miniature three-dimensional force sensor for humanoid robots, which is used for the fingertips of humanoid robots. The sensor has a total length of 34mm, a width of 24mm, and a thickness of 19mm. The force-bearing part is hemispherical. The three-dimensional sensor of the present invention is small in size.

[0017] 2. The present invention relates to a miniature three-dimensional force sensor for humanoid robots, in which an elastic body is used as the sensitive component of the sensor. Due to its small size, it adopts a simple four-beam structure and uses a single-crystal silicon semiconductor strain gauge.

[0018] 3. The miniature finger force three-dimensional force sensor for humanoid robots of this utility model adopts a single-crystal silicon semiconductor strain gauge, which is 50 times more sensitive than ordinary metal strain gauges. Therefore, under the same conditions, the full-scale output voltage is larger and the sensor resolution is higher. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of the front of the three-dimensional force sensor in this embodiment; Figure 2 This is a three-dimensional schematic diagram of the back of the three-dimensional force sensor in this embodiment; Figure 3 This is a three-dimensional schematic diagram of an elastomer; Figure 4 This is a side view of an elastomer; Figure 5 A schematic diagram showing the force-bearing adapter plate inserted into the upper cover plate; Figure 6 This is a front view of the elastomeric micro-melting single-crystal silicon semiconductor strain gauge in this embodiment; Figure 7 This is a schematic diagram of the bridging principle of the three-dimensional force sensor in this embodiment; Figure 8 ANSYS Workbench calculates the equivalent stress contour plot when Fx=100N is applied; Figure 9 ANSYS Workbench calculates the displacement contour plot when Fx=100N is applied; Figure 10 ANSYS Workbench calculates the equivalent stress contour plot when Fy=100N is applied; Figure 11 ANSYS Workbench calculates the displacement contour plot when Fy=100N is loaded; Figure 12 ANSYS Workbench calculates the equivalent stress contour plot when Fz=100N is applied; Figure 13 ANSYS Workbench calculates the displacement contour plot when Fz=100N is applied; Wherein, 1—upper cover plate, 11—spherical protrusion, 12—irregular plate, 2—elastic body, 3—lower cover plate, 31—outlet, 4—force-bearing adapter plate, 5—signal processing board, 6—first strain beam, 7—second strain beam, 8—third strain beam, 9—fourth strain beam, 10—connection hole, R1~R12—monocrystalline silicon semiconductor strain gauges. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the following description is provided in conjunction with the appendix. Figure 1 - Appendix Figure 13 The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Furthermore, 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.

[0021] like Figure 1 and 2 As shown, this embodiment is a miniature three-dimensional force sensor for humanoid robots. It is used on the fingers of humanoid robots and, in terms of its overall shape, resembles the fingertip of a human finger. The force-receiving end of the miniature three-dimensional force sensor is hemispherical and is made of a soft material, preferably silicone rubber.

[0022] For example, miniature three-dimensional force sensors for finger force, as described in this embodiment, can be installed on each of the five fingers of a humanoid robot.

[0023] Because the fingertips of humanoid robots are small, the miniature three-dimensional force sensor for finger force in this embodiment is used in the fingertips of the humanoid robot, with a total length of 34mm, a width of 24mm, and a thickness of 19mm. For example... Figure 1 As shown.

[0024] Because the miniature finger force three-dimensional force sensor of this embodiment is small in size, a single-crystal silicon semiconductor strain gauge is used on the elastomer of the three-dimensional force sensor in this embodiment, and sintering is performed using glass micro-melting technology.

[0025] Those skilled in the art are familiar with single-crystal silicon semiconductor strain gauges and glass micro-fusion technology. Since the sensitivity of single-crystal silicon semiconductor strain gauges is 50 times that of ordinary metal strain gauges, under the same conditions, the full-scale output voltage of the three-dimensional force sensor in this embodiment is larger, and the sensor resolution is higher.

[0026] like Figure 1 As shown, a miniature three-dimensional force sensor for humanoid robots resembles the tip of a human finger in its overall shape, with the force-receiving end being hemispherical; it includes an elastomer 1, a force-receiving adapter plate 4, a signal processing board 5, an upper cover plate 2, and a lower cover plate 3.

[0027] Since the elastic body 1 is the core component of the three-dimensional force sensor, but the three-dimensional force sensor is relatively small, this embodiment adopts a simple four-beam structure, with each strain beam having a rectangular cross-section.

[0028] like Figure 3 As shown, the elastic body 1 includes an elastic body rim, a central force-bearing platform, and four strain beams. The cross-section of the strain beams is rectangular. The four strain beams are evenly distributed between the force-bearing platform and the elastic body rim, with one end of the strain beam connected to the elastic body rim and the other end connected to the central force-bearing platform.

[0029] A countersunk hole and a pin hole are provided on the central load-bearing platform. These two holes are used to fix the load-bearing adapter plate 4.

[0030] The elastic hub hoop has seven threaded holes for connection to the lower cover plate 3. The lower cover plate 3 has a rectangular receiving groove. After the signal processing board 5 is welded, it is sealed and fixed in the rectangular receiving groove of the lower cover plate 3 with adhesive. Four-core wires are led out from the signal processing board 5. The arrangement of the signal processing board 5 enables the three-dimensional force sensor in this embodiment to output a digital signal, such as... Figure 1 As shown, a cable outlet 31 is provided on the lower cover plate 3 for the output of four-core wires, namely a power supply: power positive and power negative; and a signal: signal positive and signal negative; the cable outlet 31 is sealed with sealant.

[0031] In this embodiment, the upper cover plate 2 serves as the force-receiving end of the three-dimensional force sensor, and is preferably made of silicone rubber to make the measurement results more consistent with actual working conditions. The outer surface of the upper cover plate 2 is entirely a force-receiving surface, and this surface is hemispherical. A force-receiving adapter plate 4 is inserted into the upper cover plate 2 to solve the force transmission problem. Figure 5 As shown.

[0032] The force transmission process is as follows: when the upper cover plate 2 is subjected to force, it is first transmitted to the force transfer plate 4, then transmitted from the force transfer plate 4 to the central force platform of the elastic body 2, and finally transmitted to the strain beam of the elastic body 2, causing the strain beam to deform and generate micro-strain, and outputting the force value through the Wheatstone bridge.

[0033] like Figure 3 As shown, a spherical protrusion 11 is integrally formed on the end face of one end of the elastic body wheel rim. The spherical protrusion 11 is located at the front end of the entire miniature finger force three-dimensional force sensor and plays the role of protecting the force-bearing end.

[0034] like Figure 4 As shown, the upper surface of the central force-bearing platform of elastic body 1 is 0.5mm higher than the upper surface of the elastic body wheel rim, and the lower surface of the force-bearing platform is 1.2mm lower than the lower surface of the elastic body wheel rim. This provides a certain safety space for deformation when the central force-bearing platform is subjected to load, ensuring the accuracy of sensor measurements.

[0035] like Figure 1 As shown, the three-dimensional force sensor in this embodiment has a small size, resulting in limited space for the strain gauge. Since ordinary metal strain gauges are too large to be attached to the strain beam using conventional adhesive, this embodiment uses a single-crystal silicon semiconductor strain gauge, sintered onto the strain beam using glass micro-fusion technology. The single-crystal silicon semiconductor strain gauge measures 1.54mm x 0.68mm (length x width).

[0036] As is known to those skilled in the art, the sensitivity coefficient of a single-crystal silicon semiconductor strain gauge is 50 times that of a conventional metal strain gauge. Therefore, under the same conditions, the full-scale output voltage of a single-crystal silicon semiconductor strain gauge is 50 times that of a conventional metal strain gauge, thus improving the resolution of the sensor.

[0037] In this embodiment, the three-dimensional force sensor consists of twelve single-crystal silicon semiconductor strain gauges mounted on four strain beams. These strain gauges are micro-fused to the upper and lower surfaces of the strain beams using glass micro-fusion technology. Based on relevant principles in mechanics of materials, these twelve single-crystal silicon semiconductor strain gauges are arranged into three Wheatstone bridges to measure forces in the Fx, Fy, and Fz directions, respectively. This ensures structural decoupling in these three directions in principle.

[0038] In this embodiment, the lead wires of the single-crystal silicon semiconductor strain gauge are bonded to the bonding board using a bonding machine. Then, the solder joints on the bonding board are used to form a bridge. After the bridge is formed, the signal lines of the three bridge circuits are soldered to the signal processing board 5. Then, four core wires are led out from the signal processing board 5, namely: power positive and power negative, signal positive and signal negative.

[0039] like Figure 3 As shown, multiple binding plates are welded onto the irregular plate 12, which is integrally formed on the elastic body wheel rim and located between the central force-bearing platform and the elastic body wheel rim.

[0040] In this embodiment, the material of the elastomer 1 is stainless steel. The stainless steel material selected in this embodiment is 17-4 PH. After a certain heat treatment process, this stainless steel material has high yield strength, which enhances the overload capacity of the sensor.

[0041] like Figure 3 As shown, four strain beams are symmetrically arranged on the elastic body 1, namely the first strain beam 6, the second strain beam 7, the third strain beam 8, and the fourth strain beam 9.

[0042] like Figure 6As shown, twelve single-crystal silicon semiconductor strain gauges were micro-fused onto the upper and lower surfaces of the four strain beams using glass micro-fusion technology, forming three Wheatstone bridges to measure the forces in the three directions of Fx, Fy, and Fz.

[0043] like Figure 6 and 7 As shown, the three-dimensional force sensor in this embodiment employs a full-bridge measurement scheme for the three measurement directions Fx, Fy, and Fz. Bridge circuit one measures Fx, bridge circuit two measures Fy, and bridge circuit three measures Fz. Twelve single-crystal silicon semiconductor strain gauges are designated R1~R12, where R1~R4 form the full-bridge measurement for Fx, R5~R8 form the full-bridge measurement for Fy, and R9~R12 form the full-bridge measurement for Fz.

[0044] The three-dimensional force sensor in this embodiment has a range of Fx=Fy=Fz=100N.

[0045] In this embodiment, the twelve single-crystal silicon semiconductor strain gauges of the miniature finger force three-dimensional force sensor for humanoid robots are attached in the following positions: like Figure 6 As shown, in this embodiment, the micro-melting positions of the twelve single-crystal silicon semiconductor strain gauges in the three-dimensional force sensor are as follows: Figure 3 As shown, four strain beams are defined as the first strain beam 6, the second strain beam 7, the third strain beam 8, and the fourth strain beam 9. The first strain beam 6 and the second strain beam 7 are placed on the X-axis, and the third strain beam 8 and the fourth strain beam 9 are placed on the Y-axis.

[0046] When Fx is applied, the first strain beam 6 undergoes tensile deformation, and the second strain beam 7 undergoes compressive deformation. Fx is measured by a Wheatstone bridge composed of R1 to R4. According to ANSYS Workbench calculations, the upper surface of the first strain beam 6 shows slight melting at R1, and the lower surface shows slight melting at R4; the upper surface of the second strain beam 7 shows slight melting at R2, and the lower surface shows slight melting at R3; R1, R2, R3, and R4 are slightly melted close to the central force-bearing platform of the elastic body 1.

[0047] When Fy is applied, the fourth strain beam 9 undergoes tensile deformation, and the third strain beam 8 undergoes compressive deformation. Fy is measured using a Wheatstone bridge composed of R5 to R8. According to ANSYS Workbench calculations, the upper surface of the fourth strain beam 9 shows slight melting at R5, and the lower surface of the fourth strain beam 9 shows slight melting at R8; the upper surface of the third strain beam 8 shows slight melting at R6, and the lower surface of the strain beam 8 shows slight melting at R7; similarly, R5, R6, R7, and R8 show slight melting close to the central force-bearing platform of the elastic body 1.

[0048] When Fz is applied, strain beams 6, 7, 8, and 9 all undergo bending deformation. Fy is measured using a Wheatstone bridge composed of R9 to R12. ANSYS Workbench calculations show that R9 on the upper surface of strain beam 6 is slightly fused, R10 on the lower surface of strain beam 6 is slightly fused, R12 on the upper surface of strain beam 7 is slightly fused, and R11 on the lower surface of strain beam 7 is slightly fused. R9, R10, R11, and R12 are slightly fused close to the rim of elastic body 1.

[0049] The strength analysis process of elastic body 1 in this embodiment using ANSYS Workbench is as follows: As mentioned earlier, a measurement scheme using three Wheatstone bridges was employed for the three measurement directions Fx, Fy, and Fz. Simulation calculations were performed in ANSYS Workbench, with each direction subjected to full-scale loading individually. The strength and output sensitivity under full-scale loading were calculated for each direction, using 17-4PH stainless steel as the material. In the following calculations of the sensitivity of each bridge circuit, the bridge excitation voltage is assumed to be 10V.

[0050] When loading Fx=100N; such as Figure 8 and 9 As shown; The first strain beam 6 undergoes tensile deformation, and the second strain beam 7 undergoes compressive deformation, such as Figure 6 and 7 As shown, R1 is slightly melted on the upper surface of the first strain beam 6, R4 is slightly melted on the lower surface of the first strain beam 6, R2 is slightly melted on the upper surface of the second strain beam 7, and R3 is slightly melted on the lower surface of the second strain beam 7. R1 and R4 are subjected to tensile strain, while R2 and R3 are subjected to compressive strain. The composition is as follows: Figure 7 Bridge 1 in the project, calculated using ANSYS Workbench, has an equivalent stress of 44.691 MPa and a deformation of 0.001107 mm. The strain measured by R1 is... The dependent variable measured by R² is The dependent variable measured by R3 is The dependent variable measured by R4 is ,but: , —This indicates the output voltage value in the Fx direction when Fx is fully loaded; — This represents the sensitivity coefficient of a single-crystal silicon semiconductor strain gauge. In calculations, the average value is usually taken, with k=50. —This represents the strain measured at the R1 patch area of ​​the strain gauge; —This represents the strain measured in the R2 patch area of ​​the strain gauge; —This represents the strain measured in the R3 patch area of ​​the strain gauge; —This represents the strain measured at the R4 patch area of ​​strain gauge; —This represents the excitation voltage of the bridge circuit, which is taken here.

[0051] , Then the output sensitivity in the Fx direction:

[0052] When loading Fy=100N, such as Figure 10 and 11 As shown; The fourth strain beam 9 undergoes tensile deformation, while the third strain beam 8 undergoes compressive deformation, such as... Figure 6 and 7 As shown, R5 is slightly fused on the upper surface of the fourth strain beam 9, R8 is slightly fused on the lower surface of the fourth strain beam 9, R6 is slightly fused on the upper surface of the third strain beam 8, and R7 is slightly fused on the lower surface of the third strain beam 8. R5 and R8 are subjected to tensile strain, while R6 and R7 are subjected to compressive strain. The composition is as follows: Figure 7 Bridge section 2, calculated using ANSYS Workbench, has an equivalent stress of 31.258 MPa and a deformation of 0.00052201 mm. The strain measured by R5 is... The dependent variable measured by R6 is The dependent variable measured by R7 is The dependent variable measured by R8 is ,but: , —This indicates the output voltage value in the Fy direction when Fy is fully loaded; — This represents the sensitivity coefficient of a single-crystal silicon semiconductor strain gauge. In calculations, the average value is usually taken, with k=50. —This represents the strain measured in the R5 patch area of ​​the strain gauge; —This represents the strain measured in the R6 patch area of ​​the strain gauge; —This represents the strain measured in the R7 patch area of ​​the strain gauge; —This represents the strain measured in the R8 patch area of ​​the strain gauge; —This represents the excitation voltage of the bridge circuit, which is taken here.

[0053] The output sensitivity in the Fy direction is: The sensitivity is:

[0054] When loading Fz=100N, such as Figure 12 and 13 As shown; The first strain beam 6, the second strain beam 7, the third strain beam 8, and the fourth strain beam 9 all underwent bending deformation, such as Figure 6 and 7 As shown, micro-melting sheet R9 is located on the upper surface of the first strain beam 6, micro-melting sheet R10 is located on the lower surface of the first strain beam 6, micro-melting sheet R12 is located on the upper surface of the second strain beam 7, and micro-melting sheet R11 is located on the lower surface of the second strain beam 7. R9 and R12 are subjected to positive strain, while R10 and R11 are subjected to negative strain. The composition is as follows: Figure 7 Bridge 3 in the middle, calculated by ANSYS Workbench, has an equivalent stress of 108.43 MPa and a deformation of 0.011312 mm. The strain measured by R9 is... The dependent variable measured by R10 is The dependent variable measured by R11 is The dependent variable measured by R12 is ,but: , —This indicates the output voltage value in the Fz direction when Fz is fully loaded; — This represents the sensitivity coefficient of a single-crystal silicon semiconductor strain gauge. In calculations, the average value is usually taken, with k=50. —This represents the strain measured in the R9 patch area of ​​the strain gauge; —This represents the strain measured in the R10 patch area of ​​the strain gauge; —This represents the strain measured in the R11 patch area of ​​the strain gauge; —This represents the strain measured in the R12 patch area of ​​the strain gauge; —This represents the excitation voltage of the bridge circuit, which is taken here.

[0055] The output sensitivity in the Fz direction is: The sensitivity is: .

[0056] The miniature finger force three-dimensional force sensor for humanoid robots in this embodiment, after modal analysis of the elastic body using ANSYS Workbench, has a natural frequency of 12845Hz and exhibits good dynamic performance.

[0057] The miniature finger force three-dimensional force sensor for humanoid robots in this embodiment, as determined by modal analysis, is small in size, lightweight, and has high measurement resolution.

[0058] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A miniature three-dimensional force sensor for humanoid robots, characterized in that, The three-dimensional force sensor is shaped like the tip of a finger and includes an elastomer (1), a force-receiving adapter plate (4), a signal processing board (5), an upper cover plate (2), and a lower cover plate (3). The upper cover plate (2) and the lower cover plate (3) cover the upper and lower end faces of the elastomer (1), respectively. The outer surface of the upper cover plate (2) is a force-receiving surface, and the force-receiving surface is a hemispherical surface. The upper cover plate (2) is made of soft material. The force-receiving adapter plate (4) is inserted into the upper cover plate (2) and fixed on the elastomer (1). The signal processing board (5) is embedded in the lower cover plate. Inside the plate (3), the power lines and signal lines of each bridge circuit on the elastomer (1) are welded to the corresponding solder points on the signal force measuring plate. The elastomer (1) includes an elastomer wheel rim, a central force platform and four strain beams. The four strain beams are evenly distributed between the central force platform and the elastomer wheel rim, and one end of each strain beam is connected to the elastomer wheel rim, and the other end is connected to the central force platform. A total of twelve single-crystal silicon semiconductor strain gauges are set on the four strain beams to form three Wheatstone bridges to measure the forces in the three directions of Fx, Fy and Fz respectively.

2. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 1, characterized in that, A spherical protrusion (11) is integrally formed on the end face of one end of the elastomer wheel rim.

3. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 1, characterized in that, The material of the upper cover plate (2) is silicone rubber. A groove is recessed on one end face along the thickness direction of the upper cover plate (2) to accommodate the force-bearing adapter plate (4). The gap between the upper cover plate (2) and the elastic body rim is sealed with glue.

4. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 1, characterized in that, A single-crystal silicon semiconductor strain gauge is sintered on the strain beam of an elastomer (1).

5. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 1, characterized in that, The lower cover plate (3) has a recessed groove for accommodating the signal processing board (5), which is placed in the groove and sealed with sealant.

6. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 1, characterized in that, The upper surface of the center force-bearing platform of the elastomer (1) is 0.5 mm higher than the upper surface of the elastomer wheel rim, and the lower surface of the center force-bearing platform is 0.5 mm lower than the lower surface of the elastomer wheel rim.

7. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 1, characterized in that, The cross-section of the strain beam is rectangular, and twelve single-crystal silicon semiconductor strain gauges are respectively set on the upper and lower surfaces of the four strain beams.

8. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 7, characterized in that, The single-crystal silicon semiconductor strain gauge is first sintered on the strain beam of the elastic body (1). Multiple wire binding plates are provided on the elastic body (1), all of which are welded to the shaped plate (12). The shaped plate (12) is integrally formed on the elastic body wheel rim and is located between the central force platform and the elastic body wheel rim. The aluminum wire is bound to the wire binding plate by a professional wire binding machine. The wire binding plate has corresponding lead wire solder points. The corresponding solder points on the wire binding plate are bridged by wiring terminals. After the bridge is assembled, the power lines and signal lines of each bridge circuit are soldered to the corresponding solder points on the signal processing board (5). Four core wires are led out from the signal processing board (5), namely power +, power -, signal + and signal -, and led out through the outlet (31) opened on the end face of the lower cover plate (3). The outlet (31) is coated with sealant.

9. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 7, characterized in that, The material of the elastomer (1) is 17-4 PH stainless steel.

10. The miniature finger force three-dimensional force sensor for humanoid robots according to claim 7, characterized in that, The twelve single-crystal silicon semiconductor strain gauges are R1~R12, of which R1~R4 form a full-bridge measurement Fx, R5~R8 form a full-bridge measurement Fy, and R9~R12 form a full-bridge measurement Fz.

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