Medium-range miniature six-dimensional force sensor

Abstract

The utility model discloses a miniature six-dimensional force sensor with a medium range, which comprises an upper cover plate, a shell, an elastic body and a lower cover plate, the shell wraps the elastic body, the upper cover plate and the lower cover plate are respectively arranged at the upper end and the lower end of the elastic body, the elastic body and the lower cover plate are respectively provided with a semicircular hole, and a cable is clamped between the elastic body and the lower cover plate; the elastic body comprises four strain beams with L-shaped sections, every two of the four strain beams are located on the same straight line, and the two straight lines are perpendicular to each other; one end of each of the four strain beams is fixed on the stress table, and the other end of each of the four strain beams is fixed on the base; the stress table is supported by the four strain beams and is connected with the upper cover plate, and the base is connected with the lower cover plate; a plurality of strain gauges are pasted on 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 sensor has the advantages of small size, light weight, good dynamic performance, high output sensitivity and high measurement precision.

Description

Technical Field

[0001] The utility model belongs to the field of sensor measurement and relates to a medium-range miniature six-dimensional force sensor and a measuring method. Background Art

[0002] With the rapid development of science and technology, sensors have penetrated into various fields of industrial production, especially the robotics industry. As the actuator at the end of the robot, the manipulator plays a vital role in completing the corresponding work and is widely used in industrial production, military, medical and other fields. As the application level becomes deeper, the demand for robot control accuracy and sensitive perception ability is increasing, requiring small size, light weight, moderate range, high resolution, high sampling frequency, etc.

[0003] The biggest problem at present is that it is difficult to make the sensor smaller because the strain gauges produced domestically are relatively large in size and the mounting process and machining requirements must be considered. Utility Model Content

[0004] The technical problem to be solved by the utility model is that: the strain gauges currently produced domestically are relatively large in size, and it is difficult to make the sensor smaller in size in addition to the need to consider patch technology and machining requirements.

[0005] The utility model proposes a structure combining a horizontal beam and a vertical beam, and adopts a method of combining a full bridge and a half bridge, which effectively reduces the volume of the sensor and reduces the difficulty of patching.

[0006] The technical methods adopted are as follows:

[0007] A medium-range micro six-dimensional force sensor comprises an upper cover plate (1), an outer shell (2), an elastic body (3) and a lower cover plate (4), wherein the outer shell (2) wraps the elastic body (3), the upper cover plate (1) and the lower cover plate (4) are respectively arranged at the upper and lower ends of the elastic body (3), and the elastic body (3) and the lower cover plate (4) are both provided with semicircular holes, and a cable is clamped between the elastic body (3) and the lower cover plate (4); the elastic body (3) comprises four strain beams with an "L"-shaped cross section, wherein the four strain beams are arranged in pairs on a straight line, and the two straight lines are perpendicular; one end of the four strain beams is fixed on a force-bearing platform, and the other ends of the four strain beams are fixed on a base; the force-bearing platform is supported by the four strain beams, and the force-bearing platform is connected to the upper cover plate (1), and the base is connected to the lower cover plate (4); a plurality of strain gauges are attached to the four strain beams to form six Wheatstone bridges, and the forces and moments in the six directions of Fx, Fy, Fz, Tx, Ty and Tz are respectively measured.

[0008] In a further optimization of the technical solution of the utility model, a total of 20 strain gauges are pasted on the four strain beams, respectively pasted on the outer side surface, inner side surface, upper side surface and lower side surface of the four strain beams.

[0009] Further optimization of the technical solution of the utility model, 20 strain gauges are R1~R20, among which R9 and R10 form a half-bridge measurement Fx, R11 and R12 form a half-bridge measurement Fy, R13~R20 form a full-bridge measurement Fz, R1 and R2 form a half-bridge measurement Tx, R3 and R4 form a half-bridge measurement Ty, and R5~R8 form a full-bridge measurement Tz. Based on the small size of the entire sensor of the utility model and the narrow patch space, the six-dimensional force adopts a combination of full-bridge and half-bridge solutions, the two directions of Fz and Tz adopt a full-bridge measurement solution, and the four directions of Fx, Fy, Tx and Ty adopt a half-bridge measurement solution.

[0010] In a further preferred embodiment of the technical solution of the utility model, the miniature six-dimensional force sensor adopts a terminal block bridge.

[0011] As a further optimization of the technical solution of the utility model, the miniature six-axis force sensor has analog output and can be directly connected to the data collector (NST2000 / NST3000) developed by our company, supporting multiple communication methods, such as UDP, 485, 232, TCP, CAN, EtherCAT, etc.

[0012] In a further preferred embodiment of the technical solution of the utility model, the outer shell (2) is glued to the elastic body (3).

[0013] In a further optimization of the technical solution of the utility model, the "L"-shaped strain beam includes a horizontal beam and a vertical beam, and the cross-sections of the horizontal beam and the vertical beam are both quadrilaterals. Considering the small volume of the entire sensor, the strain beam adopts a solution combining the horizontal beam and the vertical beam, and ensures that there is enough patch space on the strain beam to facilitate the operation of patching.

[0014] In a further optimization of the technical solution of the utility model, strain gauges are respectively pasted on the upper side, lower side, left side and right side of the horizontal beam, and strain gauges are respectively pasted on the outer side and inner side of the vertical beam.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] 1. The most outstanding advantage of the medium-range miniature six-axis force sensor of the utility model is that the sensor is very small, with an appearance of φ25mm (diameter) X23mm (height) and a weight of less than 0.1kg. It is particularly suitable for the needs of the robotics industry, especially drag teaching.

[0017] 2. In the medium-range miniature six-dimensional force sensor of the utility model, the strain beam on the elastic body adopts a solution combining vertical beams and horizontal beams, which effectively reduces the volume of the elastic body. At the same time, considering the process requirements for pasting strain gauges, sufficient space is guaranteed when pasting strain gauges.

[0018] 3. The medium-range miniature six-axis force sensor of the utility model adopts a combination of full-bridge and half-bridge measurement schemes in the six measurement directions, taking into account the small space of the elastic body. The full-bridge measurement scheme is adopted in the two directions Fz and Tz, and the half-bridge measurement scheme is adopted in the four directions Fx, Fy, Tx and Ty.

[0019] 4. The medium-range miniature six-dimensional force sensor of the utility model has good dynamic performance. After the modal analysis of the elastic body is performed using ANSYS Workbench, the natural frequency of the elastic body is 15211 Hz.

[0020] 5. The medium-range miniature six-axis force sensor of the utility model has excellent performance, small coupling, and overload exceeding 200% after calibration.

[0021] 6. The new medium-range miniature six-axis force sensor of the utility model has the advantages of small size, light weight, good dynamic performance, high output sensitivity, and high measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a three-dimensional schematic diagram of a medium-range miniature six-axis force sensor of this embodiment;

[0023] Figure 2 is the first three-dimensional schematic diagram of an elastic body;

[0024] Figure 3 is a second three-dimensional schematic diagram of the elastic body;

[0025] Figure 4 is a top view of the elastic body patch of this embodiment;

[0026] Figure 5 yes Figure 4 Bottom view showing the patch locations of strain gauges R5, R7, and R11;

[0027] Figure 6 yes Figure 4 The left view shows the patch position of strain gauge R9;

[0028] Figure 7 yes Figure 4 The right view shows the patch position of strain gauge R10;

[0029] Figure 8 yes Figure 4 A top view showing the patch locations of strain gauges R6, R8, and R12;

[0030] Fig. 9 yes Figure 4AA cutaway view showing the patch position of strain gauge R4;

[0031] Fig.10 yes Figure 4 BB cutaway view showing the patch position of strain gauge R3;

[0032] Fig.11 yes Figure 4 DD cutaway view showing the patch position of strain gauge R1;

[0033] Fig.12 yes Figure 4 The CC cutaway view shows the patch position of strain gauge R2;

[0034] Fig.13 yes Figure 4 A cross-sectional view showing the patch locations of strain gauges R14, R15, R18, and R19;

[0035] Fig.14 This is a schematic diagram of the bridge assembly of the medium-range micro six-axis force sensor of this embodiment;

[0036] Fig.15 This is the equivalent stress cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Fx=150N;

[0037] Fig.16 This is the displacement cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Fx=150N;

[0038] Fig.17 This is the equivalent stress cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Fy=150N;

[0039] Fig.18 This is the displacement cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Fy=150N;

[0040] Fig.19 This is the equivalent stress cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Fz=150N;

[0041] Fig. 20 This is the displacement cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Fz=150N;

[0042] Fig.21This is the equivalent stress cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Tx=4Nm;

[0043] Fig. 22 This is the displacement cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Tx=4Nm;

[0044] Fig.23 This is the equivalent stress cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Ty=4Nm;

[0045] Fig.24 This is the displacement cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Ty=4Nm;

[0046] Fig.25 This is the equivalent stress cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Tz=4Nm;

[0047] Fig.26 This is the displacement cloud diagram calculated by ANSYS Workbench when the medium-range micro six-axis force sensor of this embodiment is loaded with Tz=4Nm;

[0048] Fig. 27 It is a schematic diagram of the structure of the strain gauge;

[0049] Among them, 1 is the upper cover, 2 is the outer shell, 3 is the elastic body, 4 is the lower cover, 5 is the first strain beam, 6 is the second strain beam, 7 is the third strain beam, 8 is the fourth strain beam, and R1~R20 are strain gauges. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present invention more clear, the following Figure 1 -Attached Fig. 27 The present invention is further described in detail with reference to the following 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 each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0051] like Figure 1 As shown, this embodiment is a medium-range miniature six-axis force sensor, which includes four components: an upper cover plate 1, a housing 2, an elastic body 3 and a lower cover plate 4.

[0052] The three-dimensional model of the core component elastic body 3, such as Figure 2 As shown, the upper cover plate 1 and the elastic body 3 are positioned and bolted with cylindrical pins, the lower cover plate 4 and the elastic body 3 are positioned and bolted with cylindrical pins, the shell 2 is glued to the elastic body, and semicircular holes are provided on the elastic body 3 and the lower cover plate 4 to form a cable outlet 9, and the cable is clamped between the elastic body 3 and the lower cover plate 4.

[0053] like Figure 2 and 3 As shown, four pairs of strain beams are symmetrically arranged on the elastic body 3. Considering that the elastic body 3 is relatively small, in this embodiment, the outer diameter of the elastic body 3 is 25 mm. Therefore, the strain beams adopt a combination of horizontal beams and vertical beams. Specifically:

[0054] The elastic body 3 includes four strain beams with an "L"-shaped cross-section, and the four strain beams are in a straight line in pairs, and the two straight lines are perpendicular to each other; one end of the four strain beams is fixed on the force-bearing platform, and the other ends of the four strain beams are fixed on the base; the force-bearing platform is supported by the four strain beams, and the force-bearing platform is connected to the upper cover plate 1, and the base is connected to the lower cover plate 4; multiple strain gauges are pasted on the four strain beams to form six Wheatstone bridges, which respectively measure the forces and moments in the six directions of Fx, Fy, Fz, Tx, Ty, and Tz.

[0055] like Figure 1 , 2 As shown in Figure 3, the medium-range miniature six-axis force sensor in this embodiment is mainly used in the robot dragging teaching industry. Based on the resistance strain principle, the sensor has an appearance of φ25mm (diameter) X23mm (height), a weight of less than 0.1kg, a range of: Fx=Fy=150N, Fz=250N, Tx=Ty=Tz=4Nm, and analog output. The sensor is characterized by small size and light weight.

[0056] like Figure 2 and 3 As shown, in this embodiment, the elastic body 3 is used as the sensitive component of the sensor. Since the shape of the sensor is φ25mm (diameter) X23mm (height), due to its small size, the sensor must have a certain sensitivity. Therefore, the design of the strain beam of the elastic body 3 adopts a scheme combining vertical beams and horizontal beams. The vertical beam measures the four directions of Fx, Fy, Tx and Ty, and the horizontal beam measures the two directions of Fz and Tz. Due to the small space, a scheme combining full bridge and half bridge is adopted. The two directions of Fz and Tz adopt the full bridge measurement scheme, and the four directions of Fx, Fy, Tx and Ty adopt the half bridge measurement scheme. At the same time, when designing the elastic body, it is necessary to pay attention to the requirements of the strain gauge pasting process. Therefore, when designing the elastic body, the space requirements for the strain gauge pasting must be guaranteed.

[0057] like Figure 2-3As shown, in this embodiment, the elastic body 3 includes four strain beams with an "L"-shaped cross-section. The "L"-shaped strain beam includes a horizontal beam and a vertical beam. The cross-sections of the horizontal beam and the vertical beam are both quadrilaterals. Strain gauges are respectively pasted on the upper side, lower side, left side and right side of the horizontal beam, and strain gauges are respectively pasted on the outer side and inner side of the vertical beam.

[0058] like Figure 4-14 As shown, 20 strain gauges are pasted on the four strain beams, respectively pasted on the outer side, inner side, upper side and lower side of the four strain beams. The 20 strain gauges are R1~R20, among which R9 and R10 form a half-bridge measurement Fx, R11 and R12 form a half-bridge measurement Fy, R13~R20 form a full-bridge measurement Fz, R1 and R2 form a half-bridge measurement Tx, R3 and R4 form a half-bridge measurement Ty, and R5~R8 form a full-bridge measurement Tz.

[0059] like Fig. 27 As shown, in this embodiment, the strain gauge is a purchased standard part, and two center line point marks a and b, two wire grid positioning marks c and d, and two welding points e and f are marked on the strain gauge.

[0060] like Fig.14 As shown, bridge one measures Tx, bridge two measures Ty, bridge three measures Tz, bridge four measures Fx, bridge five measures Fy, and bridge six measures Fz. These six bridges are connected in parallel. Figure 4 In the bridge diagram, R1-R20 represent strain gauges, and R represents the resistance value of the selected strain gauge, which is 350Ω.

[0061] The medium-range miniature six-axis force sensor in this embodiment has a range of: Fx=Fy=150N; Fz=250N; Tx=Ty=Tz=4Nm.

[0062] In this embodiment, the medium-range micro six-axis force sensor has 20 strain gauges attached at the following locations:

[0063] like Figure 2 and 3 As shown, four strain beams are defined as a first strain beam 5, a second strain beam 6, a third strain beam 7 and a fourth strain beam 8. The first strain beam 5 and the second strain beam 6 are located on the same straight line, which is defined as a first straight line; the third strain beam 7 and the fourth strain beam 8 are located on the same straight line, which is defined as a second straight line.

[0064] Strain gauges R9 and R10 are respectively pasted on the outer sides of the vertical beams of the first strain beam 5 and the second strain beam 6, with R9 pasted from the bottom and the welding point facing upward; R10 pasted from the bottom and the welding point facing upward; Figure 6 and 7 shown.

[0065] Strain gauges R11 and R12 are respectively pasted on the outer sides of the vertical beams of the third strain beam 7 and the fourth strain beam 8; R11 is pasted from the bottom with the welding point facing upward; R12 is pasted from the bottom with the welding point facing upward; Figure 5 and 8 shown.

[0066] Strain gauges R13 and R16 are respectively attached to the upper side of the first strain beam 5 and the second strain beam 6. R13 is attached to the upper side of the strain beam 5 with the welding point facing outwards, and R16 is attached to the upper side of the strain beam 6 with the welding point facing outwards. R13 and R16 are attached symmetrically about the Y axis, as shown in FIG. Figure 4 and 13 shown.

[0067] Strain gauges R15 and R14 are respectively attached to the lower side of the first strain beam 5 and the second strain beam 6. R15 is attached to the lower side of the strain beam 5 with the welding point facing inward, and R16 is attached to the lower side of the strain beam 6 with the welding point facing inward. R15 and R14 are attached symmetrically about the Y axis, as shown in FIG. Figure 4 and 13 shown.

[0068] like Fig.13 As shown, L4 represents the distance between R15 and R14 and the wire grid positioning mark symmetrically about the Y axis; L4 represents the distance between R19 and R18 and the wire grid positioning mark symmetrically about the X axis; in this embodiment, L4 and L5 are preferably 10.4 cm.

[0069] Strain gauges R20 and R17 are respectively attached to the upper side of the third strain beam 7 and the fourth strain beam 8. R20 is attached to the upper side of the strain beam 7 with the welding point facing outwards, and R17 is attached to the upper side of the strain beam 8 with the welding point facing outwards. R20 and R17 are attached symmetrically about the X axis, as shown in FIG. Figure 4 and 13 shown.

[0070] like Figure 4 As shown, in this embodiment, R17 and R20 are symmetrical about the X axis, and the distance between the wire grid positioning marks is L1. For the medium-range micro six-axis force sensor of this embodiment, L1 is preferably 12.2 cm.

[0071] Strain gauges R19 and R18 are respectively attached to the lower side of the third strain beam 7 and the fourth strain beam 8. R19 is attached to the lower side of the strain beam 7 with the welding point facing inwards, and R18 is attached to the lower side of the strain beam 8 with the welding point facing inwards. R19 and R18 are attached symmetrically about the X axis, as shown in FIG. Figure 4 and 13 shown.

[0072] Paste the strain gauge R2 on the inner side of the vertical beam of the third strain beam 7, starting from the bottom and with the welding point facing upward; paste the strain gauge R1 on the inner side of the vertical beam of the fourth strain beam 8, starting from the bottom and with the welding point facing upward; Fig.11 and 12 shown.

[0073] Paste the strain gauge R3 on the inner side of the vertical beam of the first strain beam 5, starting from the bottom and with the welding point facing upward; paste the strain gauge R4 on the inner side of the vertical beam of the second strain beam 6, starting from the bottom and with the welding point facing upward; Fig. 9 and 10 shown.

[0074] Strain gauges R5 and R6 are respectively attached to the left and right sides of the crossbeam of the first strain beam 5, and strain gauges R7 and R8 are respectively attached to the left and right sides of the crossbeam of the second strain beam 6. R6 and R8 are symmetrical about the Z axis, and R5 and R7 are symmetrical about the Z axis. The welding points of the four strain gauges R5, R6, R7 and R8 face outwards, as shown in FIG. Figure 4 , 5 and 8.

[0075] like Figure 5 As shown, in this embodiment, R5 and R7 are symmetrical about the Z axis, and the distance between the wire grid positioning marks is L2. For the medium-range miniature six-axis force sensor in this embodiment, L2 is preferably 16.2 cm.

[0076] like Figure 5 As shown, L3 represents the distance between the R5 and R7 wire grid positioning marks and the upper side of the beam. For the medium-range miniature six-axis force sensor of this embodiment, L3 is preferably 1.6 cm.

[0077] The medium-range micro six-axis force sensor in this embodiment is subjected to modal analysis of the elastic body by ANSYS Workbench. The medium-range micro six-axis force sensor has a natural frequency of 15211 Hz and has good dynamic performance.

[0078] The specific process of modal analysis of elastic body using ANSYS Workbench is as follows:

[0079] As mentioned above, the six measurement directions of Fx, Fy, Fz, Tx, Ty and Tz adopt a combination of full-bridge and half-bridge solutions. Simulation calculations are performed in ANSYS Workbench, and full-scale loading is performed in each direction separately. The strength of each direction when loaded with full scale is calculated. Because the selected material is LY12CZ with a yield strength of 360MPa, the equivalent stress value obtained by simulation calculation must be less than the yield strength of 360MPa. The output sensitivity of each bridge is calculated separately. When calculating the sensitivity of each bridge, the bridge excitation voltage is calculated as 5V.

[0080] When the load Fx=150N, the vertical beams of the first strain beam 5 and the second strain beam 6 are bent; strain gauges R9 and R10 are respectively attached to the root of the outer side of the vertical beams of the first strain beam 5 and the second strain beam 6, with the welding points facing upwards. Figure 6 and 7 As shown. The strain gauge R9 is subjected to tensile strain, and the strain gauge R10 is subjected to compressive strain. Fig.14 The bridge path 4 in the figure is calculated by ANSYS Workbench, as shown in Fig.15 and 16 As shown, the equivalent stress is 53.428MPa, the deformation is 0.0095707mm, and the strain measured by R9 is 4.2119×10 -4 , the strain measured by R10 is -4.1091×10 -4 ,but:

[0081]

[0082] U Fx ——Indicates the output voltage value in the Fx direction when Fx is fully loaded;

[0083] k——represents the sensitivity coefficient of the strain gauge. The average value is usually taken during calculation, and k=2;

[0084] ε 9 ——Indicates the strain measured in the patch area of ​​strain gauge R9;

[0085] ε 10 ——Indicates the strain measured in the patch area of ​​strain gauge R10;

[0086] U i —— represents the excitation voltage of the bridge circuit, here we take U i =5V

[0087]

[0088] Then the output sensitivity in the Fx direction is: .

[0089] When Fy=150N is loaded, the vertical beams of the third strain beam 7 and the fourth strain beam 8 are bent; strain gauges R11 and R12 are respectively pasted on the root of the outer side of the vertical beams of the third strain beam 7 and the fourth strain beam 8, with the welding points facing upwards; Figure 5 and 8 As shown. Among them, strain gauge R11 is subjected to tensile strain, strain gauge R12 is subjected to compressive strain, and the composition is as follows Fig.14 The bridge path 5 in the figure is calculated by ANSYS Workbench, as shown in Fig.17 and 18As shown in the figure, the equivalent stress is 52.826 MPa, the deformation is 0.00949 mm, and the strain measured by R11 is 4.1643×10 -4 , the strain measured by R10 is -4.1831×10 -4 ,but:

[0090]

[0091] U Fy ——Indicates the output voltage value in the Fy direction when Fy is fully loaded;

[0092] k——represents the sensitivity coefficient of the strain gauge. The average value is usually taken during calculation, and k=2;

[0093] ε 11 ——Indicates the strain measured in the patch area of ​​strain gauge R11;

[0094] ε 12 ——Indicates the strain measured in the patch area of ​​strain gauge R12;

[0095] U i —— represents the excitation voltage of the bridge circuit, here we take U i =5V

[0096] Then the output sensitivity in the Fy direction is: .

[0097] When loaded with Fz-250N, the crossbeams of the four strain beams are bent. Strain gauges R13 and R14 are respectively pasted on the upper side and lower side of the crossbeam of the first strain beam 5, strain gauges R16 and R15 are respectively pasted on the upper side and lower side of the crossbeam of the second strain beam 6, strain gauges R20 and R19 are respectively pasted on the upper side and lower side of the crossbeam of the third strain beam 7, and strain gauges R17 and R18 are respectively pasted on the upper side and lower side of the crossbeam of the fourth strain beam 8. The welding points of R13, R16, R20 and R17 face outwards, and the welding points of R15, R14, R19 and R18 face inwards, as shown in FIG. Figure 4 and 13 shown.

[0098] Among them, strain gauges R13, R16, R20, and R17 are subjected to tensile strain, and strain gauges R14, R15, R19, and R18 are subjected to compressive strain. The composition is as follows: Fig.14 The bridge path 6 in the figure is calculated by ANSYS Workbench, as shown in Fig.19 and 20 As shown, the equivalent stress is 55.394MPa, the deformation is 0.008101mm, and the strain measured by R13 is 2.8785×10 -4 , the strain measured by R14 is -2.2863×10-4 , the strain measured by R15 is -2.3004×10 -4 , the strain measured by R16 is 2.8784×10 -4 , the strain measured by R17 is 2.8782×10 -4 , the strain measured by R18 is -2.2933×10 -4 , the strain measured by R19 is -2.2747×10 -4 , the strain measured by R20 is 2.9383×10 -4 ,but:

[0099]

[0100] U Fz ——Indicates the output voltage value in the Fz direction when Fz is fully loaded;

[0101] k——represents the sensitivity coefficient of the strain gauge. The average value is usually taken during calculation, and k=2;

[0102] ε 13 ——Indicates the strain measured in the patch area of ​​strain gauge R13;

[0103] ε 14 ——Indicates the strain measured in the patch area of ​​strain gauge R14;

[0104] ε 15 ——Indicates the strain measured in the patch area of ​​strain gauge R15;

[0105] ε 16 ——Indicates the strain measured in the patch area of ​​strain gauge R16;

[0106] ε 17 ——Indicates the strain measured in the patch area of ​​strain gauge R17;

[0107] ε 18 ——Indicates the strain measured in the patch area of ​​strain gauge R18;

[0108] ε 19 ——Indicates the strain measured in the patch area of ​​strain gauge R19;

[0109] ε 20 ——Indicates the strain measured in the patch area of ​​strain gauge R20;

[0110] U i —— represents the excitation voltage of the bridge circuit, here we take U i =5V

[0111] Then the output sensitivity in the Fz direction is: .

[0112] When Tx=4Nm is loaded, the vertical beams of the third strain beam 7 and the fourth strain beam 8 are bent, and the strain gauge R1 is pasted on the root of the inner side surface of the vertical beam of the third strain beam 7 with the welding point facing upward, and the strain gauge R2 is pasted on the root of the inner side surface of the vertical beam of the fourth strain beam 8 with the welding point facing upward; Fig.11 and 12 As shown. Among them, strain gauge R1 is subjected to tensile strain, strain gauge R2 is subjected to compressive strain, and the composition is as follows Fig.14 The bridge path 1 in the figure is calculated by ANSYS Workbench. Fig.21 and 22 As shown, the equivalent stress is 226.69MPa, the deformation is 0.028314mm, and the strain measured by R1 is 9.7656×10 -4 , the strain measured by R2 is -9.7435×10 -4 ,but:

[0113]

[0114] U Tx ——Indicates the output voltage value in the Tx direction when Tx is fully loaded;

[0115] k——represents the sensitivity coefficient of the strain gauge. The average value is usually taken during calculation, and k=2;

[0116] ε 1 ——Indicates the strain measured in the patch area of ​​strain gauge R1;

[0117] ε 2 ——Indicates the strain measured in the patch area of ​​strain gauge R2;

[0118] U i —— represents the excitation voltage of the bridge circuit, here we take U i =5V

[0119] Then the output sensitivity in the Tx direction is: .

[0120] When the load is Ty=4Nm, the vertical beams of the first strain beam 5 and the second strain beam 6 are bent, and the strain gauge R3 is pasted on the root of the inner side of the vertical beam of the first strain beam 5, with the welding point facing upward, and the strain gauge R4 is pasted on the root of the inner side of the vertical beam of the second strain beam 6, with the welding point facing upward; Fig. 9 and 10 As shown. Among them, strain gauge R3 is subjected to tensile strain, strain gauge R4 is subjected to compressive strain, and the composition is as follows Figure 4 The bridge 2 in the figure is calculated by ANSYS Workbench, as shown in Fig.23 and 24As shown, the equivalent stress is 225.52MPa, the deformation is 0.02909mm, and the strain measured by R3 is 9.767×10 -4 , the strain measured by R4 is -9.7211×10 -4 ,but:

[0121]

[0122] U Ty ——Indicates the output voltage value in the Ty direction when Ty is fully loaded;

[0123] k——represents the sensitivity coefficient of the strain gauge. The average value is usually taken during calculation, and k=2;

[0124] ε 3 ——Indicates the strain measured in the patch area of ​​strain gauge R3;

[0125] ε 4 ——Indicates the strain measured in the patch area of ​​strain gauge R4;

[0126] U i —— represents the excitation voltage of the bridge circuit, here we take U i =5V

[0127] Then the output sensitivity in the Ty direction is: .

[0128] When Tz=4Nm is loaded, the crossbeams of the four strain beams are bent. Strain gauges R5 and R6 are respectively attached to the left and right sides of the crossbeam of the first strain beam 5, and strain gauges R7 and R8 are respectively attached to the left and right sides of the crossbeam of the second strain beam 6. The welding points of R5, R6, R7 and R8 face outwards. Figure 4 As shown. Among them, strain gauges R5 and R8 are subjected to tensile strain, strain gauges R6 and R7 are subjected to compressive strain, and the composition is as follows Figure 4 The bridge path 1 in the figure is calculated by ANSYS Workbench. Fig.25 and 26 As shown, the equivalent stress is 151.37MPa, the deformation is 0.036719mm, and the strain measured by R5 is 3.1958×10 -4 , the strain measured by R6 is -3.2318×10 -4 , the strain measured by R7 is -3.2491×10 -4 , the strain measured by R8 is 3.2695×10 -4 ,but:

[0129]

[0130] U Tz——Indicates the output voltage value in the Tz direction when Tz is fully loaded;

[0131] k——represents the sensitivity coefficient of the strain gauge. The average value is usually taken during calculation, and k=2;

[0132] ε 5 ——Indicates the strain measured in the patch area of ​​strain gauge R5;

[0133] ε 6 ——Indicates the strain measured in the patch area of ​​strain gauge R6;

[0134] U i —— represents the excitation voltage of the bridge circuit, here we take U i =5V

[0135] Then the output sensitivity in the Ty direction is: .

[0136] The medium-range micro six-axis force sensor in this embodiment has the advantages of small size, light weight, good dynamic performance, high measurement accuracy, etc., through modal analysis.

[0137] The medium-range miniature six-axis force sensor in this embodiment is connected to an NST2000 data collector developed by Nanjing Shenyuansheng Intelligent Technology Co., Ltd., and uses UDP communication. The sensor is calibrated in accordance with the "Multi-component Force Sensor Calibration Specification" (Standard No.: JJF 1560-2016). The calibration calculation results are shown in Table 1 below.

[0138] Table 1

[0139]

[0140] In summary, according to the calibration data in Table 1, the medium-range miniature six-axis force sensor of this embodiment has high precision and excellent performance, and is suitable for use in the robotics industry.

[0141] It is easy for those skilled in the art to understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A medium-range miniature six-axis force sensor, characterized in that: It comprises an upper cover plate (1), an outer shell (2), an elastic body (3) and a lower cover plate (4), wherein the outer shell (2) wraps the elastic body (3), the upper cover plate (1) and the lower cover plate (4) are respectively arranged at the upper and lower ends of the elastic body (3), and semicircular holes are provided on the elastic body (3) and the lower cover plate (4), so that the cable is clamped between the elastic body (3) and the lower cover plate (4); The elastic body (3) comprises four strain beams with an "L"-shaped cross section, wherein the four strain beams are arranged in pairs on a straight line, and the two straight lines are perpendicular to each other; one end of each of the four strain beams is fixed on a force-bearing platform, and the other ends of each of the four strain beams are fixed on a base; the force-bearing platform is supported by the four strain beams, and the force-bearing platform is connected to an upper cover plate (1), and the base is connected to a lower cover plate (4); a plurality of strain gauges are attached to the four strain beams to form six Wheatstone bridges, and the forces and moments in the six directions of Fx, Fy, Fz, Tx, Ty, and Tz are measured respectively.

2. The medium-range miniature six-axis force sensor according to claim 1, characterized in that: A total of 20 strain gauges are pasted on the four strain beams, respectively on the outer side surface, inner side surface, upper side surface and lower side surface of the four strain beams.

3. The medium-range miniature six-axis force sensor according to claim 2, characterized in that: The 20 strain gauges are R1~R20, among which R9 and R10 form a half-bridge measurement Fx, R11 and R12 form a half-bridge measurement Fy, R13~R20 form a full-bridge measurement Fz, R1 and R2 form a half-bridge measurement Tx, R3 and R4 form a half-bridge measurement Ty, and R5~R8 form a full-bridge measurement Tz.

4. The medium-range miniature six-axis force sensor according to claim 1, characterized in that: The miniature six-dimensional force sensor adopts a terminal block bridge.

5. The medium-range miniature six-axis force sensor according to claim 1, characterized in that: The miniature six-dimensional force sensor has analog output.

6. The medium-range miniature six-axis force sensor according to claim 1, characterized in that: The housing (2) is glued to the elastic body (3).

7. The medium-range miniature six-axis force sensor according to claim 1, characterized in that: The "L"-shaped strain beam includes a horizontal beam and a vertical beam, and the cross-sections of the horizontal beam and the vertical beam are both quadrilateral.

8. The medium-range miniature six-axis force sensor according to claim 7, characterized in that: Strain gauges are respectively attached to the upper side, lower side, left side and right side of the horizontal beam, and strain gauges are respectively attached to the outer side and inner side of the vertical beam.

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