Full-plane six-dimensional force sensor elastomer

Abstract

The invention discloses a full-plane six-dimensional force sensor elastic body, relates to the field of six-dimensional force sensor elastic bodies, and mainly aims at solving the problem that an existing six-dimensional force sensor elastic body is difficult to consider small size, light weight and large bearing capacity at the same time, the elastic body comprises an outer ring and an inner ring, and the outer ring is arranged on the outer side of the inner ring in a sleeving mode; the outer ring and the inner ring are connected through four beam body assemblies, the four beam body assemblies are arranged between the outer ring and the inner ring at equal intervals in the circumferential direction, one end of each beam body assembly and the outer ring are integrally formed, the other end of each beam body assembly and the inner ring are integrally formed, and each beam body assembly is provided with a strain measurement unit assembly. The elastic body structure is mainly used as an elastic body structure in a full-plane six-dimensional force sensor.

Description

Technical Field

[0001] The invention relates to the field of six-dimensional force sensor elastomers, and in particular to a full-plane six-dimensional force sensor elastomer. Background Art

[0002] The demand for robots in the process of developing new scenarios is accelerating the requirements for the comprehensive performance of six-dimensional force sensors. Nowadays, people not only want robots to move stably and accurately, but also want them to be able to work in scenarios with large loads. Six-dimensional force sensors have become one of the key components of robots because they can simultaneously perceive full force information in three-dimensional space, which is bound to lead to a rapid increase in demand for six-dimensional force sensors with large load-bearing capacity.

[0003] Existing six-axis force sensors generally increase their load-bearing capacity by increasing thickness, which will increase unnecessary size and mass. If you do not want to increase the thickness, adding multiple load-bearing beams to increase the load-bearing capacity will increase the unnecessary lateral stiffness, which will significantly reduce its lateral sensitivity. At the same time, the strain measurement units of existing six-axis force sensors are mostly arranged on different surfaces of the strain beams, and the arrangement process is cumbersome and inefficient.

[0004] Chinese patent CN1220037C discloses a miniature full-plane six-dimensional force and torque sensor, which is a flat disc-shaped structure, consisting of a central body, three outer ring beams around the central body at an angle of 60 degrees to each other, three inner ring beams radially arranged in the outer ring beam at an angle of 120 degrees to each other, and a strain gauge, wherein the three outer ring beams are respectively composed of two thin-sheet strain beams, the inner ends of the three inner ring beams are connected to the central body, and the outer ends of the three inner ring beams are respectively connected to the intersection between the two outer ring beams, the central body, the outer ring beam and the inner ring beam are connected into an integral structure, and strain gauges are respectively arranged on each outer ring beam and the inner ring beam. The sensor is a full-plane structure that facilitates the arrangement of strain measurement units and is suitable for micro-machining. At the same time, the sensor is small in size and high in precision, and can be used for the fingertips of the second-generation humanoid robot's dexterous hands to improve the intelligence of the entire robot system, but it has the problem that it is difficult to balance small size, light weight and large carrying capacity.

[0005] Chinese patent CN115683434B discloses a six-axis force / torque measuring device for a space robot arm that is suitable for crawling inchworms. The device uses a flexible load-sharing beam to bear most of the force / torque load, which can improve the rigidity of the measuring device and also play an overload protection role; a T-type sensitive beam with a special structure is used to bear a small part of the force / torque load, which plays a detection and measurement role. According to the actual working conditions, the stiffness ratio of the load-sharing beam and the sensitive beam is reasonably allocated to solve the contradictory relationship between high rigidity, large overload and sensitivity, so that it is more suitable for crawling space robot arms. Although this structure improves the measurement rigidity of the sensor, the improvement of this rigidity is all-round, which will cause the radial rigidity that does not need to be improved to be too large, resulting in a significant reduction in lateral sensitivity, and the arrangement position of its strain measurement unit is located in different planes, and the sputtering process cannot be used to arrange the strain measurement unit. The arrangement consistency of the strain measurement unit is poor and the efficiency is low. Summary of the invention

[0006] The present invention mainly aims at the problem that the existing six-dimensional force sensor elastic body is difficult to achieve small size, light weight and large load-bearing capacity, and thus provides a full-plane six-dimensional force sensor elastic body;

[0007] A full-plane six-dimensional force sensor elastic body, the elastic body comprises an outer ring and an inner ring, the outer ring is sleeved on the outer side of the inner ring, the outer ring and the inner ring are connected by four beam body components, the four beam body components are equidistantly arranged between the outer ring and the inner ring along the circumferential direction, one end of each beam body component is integrally formed with the outer ring, the other end of each beam body component is integrally formed with the inner ring, and a strain measurement unit component is installed on each beam body component;

[0008] Furthermore, the elastic body also includes four double-rigidity reinforcement beams, each of which is located in the middle of two adjacent beam body components, and one end of each double-rigidity reinforcement beam is integrally formed with the outer ring, and the other end of each double-rigidity reinforcement beam is integrally formed with the inner ring.

[0009] Furthermore, the double-rigidity reinforcement beam includes four reinforcement beam bodies, which are connected end to end in sequence and arranged in a diamond shape, and two oppositely arranged tips in the double-rigidity reinforcement beam are connecting parts with the outer ring and the inner ring, one of the tips is formed integrally with the outer ring, and the other tip is formed integrally with the inner ring;

[0010] Further, the beam assembly includes an inner beam and two parallel beams, one end of the inner beam is integrally formed with the inner ring, the two parallel beams are relatively arranged on both sides of the other end of the inner beam, and one end of each parallel beam is integrally formed with the inner beam through a flexible beam, the other end of each parallel beam is integrally formed with the outer ring, each flexible beam and its corresponding parallel beam are located on the same center line, and each flexible beam and its corresponding inner beam are arranged perpendicularly;

[0011] Further, the strain measurement unit assembly includes a shear strain measurement unit and two tension and compression strain measurement unit groups, the shear strain measurement unit is installed on the top of the inner beam, and each tension and compression strain measurement unit group is correspondingly installed on the top of a parallel beam;

[0012] Furthermore, each tension and compression strain measuring unit group includes two tension and compression strain measuring units, and the two tension and compression strain measuring units are symmetrically installed at two ends of the top of the parallel beam along the center line of the length direction of the parallel beam:

[0013] Further, the shear strain measuring unit located on the inner beam and the tension and compression strain measuring unit located on the parallel beam are both located in the same plane;

[0014] Furthermore, six inner ring through holes are processed at equal intervals on the top of the inner ring along the circumferential direction, and two of the six inner ring through holes are respectively arranged corresponding to two inner beams arranged opposite to each other;

[0015] Furthermore, eight outer ring through holes are processed on the top of the outer ring along the circumferential direction, and four of the eight outer ring through holes are respectively located in correspondence with a double-rigidity reinforcement beam, and the other four of the eight outer ring through holes are respectively located in correspondence with an inner beam;

[0016] Furthermore, the outer ring, inner ring, inner beam, double-rigidity reinforced beam, flexible beam and parallel beam are all made of aluminum alloy, stainless steel or alloy steel;

[0017] The beneficial effects of this application compared to the prior art are as follows:

[0018] 1. The present invention provides a full-plane six-dimensional force sensor elastomer, which uses a flexible beam to connect the parallel beam and the inner beam. When a tangential force Fx or Fy perpendicular to the thickness direction of the flexible beam is applied, the stiffness along the length and height direction of the flexible beam is much greater than the stiffness in the thickness direction, resulting in a small coupling effect with the My or Mx direction, thereby reducing the inter-dimensional coupling. Since the effects of Mz and Fz are relatively independent, their coupling effect is also small. By placing the parallel beam between the flexible beam and the outer ring, and the flexible beam on the center line of the parallel beam, the size of the sensor is less affected by the size of the parallel beam, making the elastomer structure more compact. At the same time, this arrangement scheme also reduces the distance from the flexible beam to the center of the sensor, thereby reducing the torsional deformation of the flexible beam when subjected to force, and improving the stiffness and sensitivity of the elastomer.

[0019] 2. The full-plane six-dimensional force sensor elastomer provided by the present invention adopts a double-rigidity reinforcement beam to improve the axial stiffness without changing the lateral sensitivity of the elastomer, thereby reducing the thickness of the elastomer. At the same time, it can avoid the problem of excessively increasing the thickness of the parallel beams to increase the axial stiffness, and avoid excessive strain differences in the strain measurement areas of the same parallel beams, thereby improving the measurement sensitivity of the elastomer in the Fz, Mx and My directions.

[0020] 3. The present invention provides a full-plane six-dimensional force sensor elastomer, which is designed as a full-plane structure so that all strain measurement units are located in the same plane of the elastomer, and the strain measurement units can be arranged on the elastomer through a sputtering process, thereby improving the arrangement accuracy and efficiency of the strain measurement units. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the overall structure of a full-plane six-dimensional force sensor elastic body described in this application;

[0022] In the figure, 1 is an outer ring, 2 is an outer ring through hole, 3 is a flexible beam, 4 is a parallel beam, 5 is a double-rigidity reinforced beam, 6 is an inner beam, 7 is an inner ring, 8 is an inner ring through hole, 9 is a pin hole, 10 is a shear strain measuring unit, and 11 is a tension and compression strain measuring unit. DETAILED DESCRIPTION

[0023] Specific implementation method 1: Combination Figure 1 To illustrate this embodiment, a full-plane six-dimensional force sensor elastomer is provided in this embodiment, and the elastomer includes an outer ring 1 and an inner ring 7. The outer ring 1 is sleeved on the outside of the inner ring 7. The outer ring 1 and the inner ring 7 are connected by four beam body assemblies. The four beam body assemblies are equidistantly arranged between the outer ring 1 and the inner ring 7 along the circumferential direction, and one end of each beam body assembly is integrally formed with the outer ring 1, and the other end of each beam body assembly is integrally formed with the inner ring 7. A strain measurement unit assembly is installed on each beam body assembly.

[0024] Specific implementation method 2: Combination Figure 1 This embodiment is described. The difference between this embodiment and the first embodiment is that the elastic body further includes four double-rigidity reinforcement beams 5, each of which is located in the middle of two adjacent beam body components, and one end of each double-rigidity reinforcement beam 5 is integrally formed with the outer ring 1, and the other end of each double-rigidity reinforcement beam 5 is integrally formed with the inner ring 7. Other components and connection methods are the same as those in the first embodiment.

[0025] Specific implementation method three: Combination Figure 1To explain this embodiment, the difference between this embodiment and the second embodiment is that the double-rigidity reinforcement beam 5 includes four reinforcement beam bodies, and the four reinforcement beam bodies are sequentially connected end to end in a diamond arrangement, and the two oppositely arranged tips in the double-rigidity reinforcement beam 5 are connecting parts with the outer ring 1 and the inner ring 7, one of the tips is integrally formed with the outer ring 1, and the other tip is integrally formed with the inner ring 7. Other components and connection methods are the same as those in the second embodiment.

[0026] In combination with the description of the second and third specific embodiments, the dual-rigidity reinforcement beam 5 is used to improve the axial stiffness without changing the lateral sensitivity of the elastomer, thereby reducing the thickness of the elastomer. At the same time, it can avoid the problem of excessively increasing the thickness of the parallel beam to increase the axial stiffness, and avoid excessive strain differences in the strain measurement areas of the same parallel beam 4, thereby improving the measurement sensitivity of the elastomer in the Fz, Mx and My directions.

[0027] Specific implementation method four: Combination Figure 1 This embodiment is described. The difference between this embodiment and the third embodiment is that the beam assembly includes an inner beam 6 and two parallel beams 4. One end of the inner beam 6 is formed integrally with the inner ring 7. The two parallel beams 4 are arranged oppositely on both sides of the other end of the inner beam 6. One end of each parallel beam 4 is formed integrally with the inner beam 6 through a flexible beam 3. The other end of each parallel beam 4 is formed integrally with the outer ring 1. Each flexible beam 3 and its corresponding parallel beam 4 are located on the same center line. Each flexible beam 3 and its corresponding inner beam 6 are arranged vertically. Other components and connection methods are the same as those of the third embodiment.

[0028] In this embodiment, by placing the parallel beam between the flexible beam and the outer ring, and placing the flexible beam on the center line of the parallel beam, the size of the sensor is less affected by the size of the parallel beam, making the elastic body structure more compact. At the same time, this arrangement scheme also reduces the distance from the flexible beam to the center of the sensor, thereby reducing the torsional deformation of the flexible beam when subjected to force, and improving the stiffness and sensitivity of the elastic body.

[0029] In this embodiment, a T-shaped groove structure is formed between the beam body assembly composed of the inner beam 6 and the two parallel beams 4 and the outer ring 1. The T-shaped groove structure helps to dissipate heat from the sensor elastomer.

[0030] Specific implementation method five: Combination Figure 1 This embodiment is described. The difference between this embodiment and the fourth embodiment is that the strain measurement unit assembly includes a shear strain measurement unit 10 and two tension and compression strain measurement unit groups. The shear strain measurement unit 10 is installed on the top of the inner beam 6, and each tension and compression strain measurement unit group is correspondingly installed on the top of a parallel beam 4. Other components and connection methods are the same as those of the fourth embodiment.

[0031] Specific implementation method six: Combination Figure 1 This embodiment is described. The difference between this embodiment and the fifth embodiment is that each tension and compression strain measuring unit group includes two tension and compression strain measuring units 11, and the two tension and compression strain measuring units 11 are symmetrically installed at the two ends of the top of the parallel beam 4 along the center line of the length direction of the parallel beam 4. Other components and connection methods are the same as those of the fifth embodiment.

[0032] Specific implementation method seven: Combination Figure 1 This embodiment is described. The difference between this embodiment and the sixth embodiment is that the shear strain measuring unit 10 located on the inner beam 6 and the tension and compression strain measuring unit 11 located on the parallel beam 4 are both located in the same plane. Other components and connection methods are the same as those of the sixth embodiment.

[0033] In combination with the description of the fifth to seventh specific embodiments, the shear strain measurement unit 10 and the tensile and compressive strain measurement unit 11 are both arranged on the elastic body by a sputtering process, and such an arrangement is conducive to improving the arrangement accuracy and efficiency of the strain measurement units.

[0034] Specific implementation method eight: Combination Figure 1 This embodiment is described. The difference between this embodiment and the seventh embodiment is that six inner ring through holes 8 are processed at equal intervals along the circumferential direction on the top of the inner ring 7, and two of the six inner ring through holes 8 are respectively arranged corresponding to two oppositely arranged inner beams 6. The other components and connection methods are the same as those of the seventh embodiment.

[0035] Specific implementation method nine: Combination Figure 1 This embodiment is described. The difference between this embodiment and the eighth embodiment is that eight outer ring through holes 2 are processed along the circumferential direction on the top of the outer ring 1, and four of the eight outer ring through holes 2 are respectively located in a corresponding arrangement of a double-rigidity reinforcement beam 5, and the other four of the eight outer ring through holes 2 are respectively arranged in a corresponding arrangement of an inner beam 6. The other components and connection methods are the same as those of the eighth embodiment.

[0036] In combination with the specific implementations eight and nine, each outer ring through hole 2 at the top of the outer ring 1 corresponding to the double rigidity reinforcement beam 5 has its center point located on the line where the center point of the inner ring 7 and the center point of the double rigidity reinforcement beam 5 corresponding to the outer ring through hole 2 are located, and each outer ring through hole 2 at the top of the outer ring 1 corresponding to the inner beam 6 has its center point located on one side of the line where the center point of the inner ring 7 and the center point of the inner beam 6 corresponding to the outer ring through hole 2 are located. Four pin holes 9 are also processed on the top of the outer ring 1, and each pin hole 9 is arranged on the other side of the line where the center point of the inner ring 7 and the center point of an inner beam 6 are located.

[0037] Specific implementation method ten: Combination Figure 1This embodiment is described. The difference between this embodiment and the ninth embodiment is that the outer ring 1, the inner ring 7, the inner beam 6, the double-rigidity reinforcement beam 5, the flexible beam 3 and the parallel beam 4 are all made of aluminum alloy, stainless steel or alloy steel. The other components and connection methods are the same as those of the ninth embodiment.

[0038] The present invention has been disclosed as above with preferred implementation cases, but it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent implementation cases with equivalent changes by using the above-disclosed structures and technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above implementation cases based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

[0039] How it works

[0040] Take the measurement of tangential force Fx as an example: the tangential force Fx is applied to the lower end face of the inner ring 7, the upper end face of the outer ring 1 is a fixed face, and the stiffness of the flexible beam 3 along the length direction (along the X-axis direction) is greater than its stiffness along the thickness direction (along the Y-axis direction). Therefore, the inner beam 6, parallel beam 4, double-rigidity reinforced beam 5 and flexible beam 3 parallel to the Fx direction are all considered rigid, the inner beam 6, parallel beam 4, double-rigidity reinforced beam 5 and flexible beam 3 perpendicular to the Fx direction are all considered flexible, and the inner beam 6 perpendicular to the Fx direction is considered a cantilever beam. A strain sensitive area is formed on the inner beam 6, thus forming a strain bridge, and then Fx can be measured. Similarly, the tangential force Fy can be measured.

[0041] Take the measurement of axial force Fz as an example: the axial force Fz is applied to the lower end face of the inner ring 7, the upper end face of the outer ring 1 is a fixed surface, and is transmitted to the parallel beam 4 through the inner beam 6. The stiffness of the flexible beam 3 and the double-rigidity reinforced beam 5 along the Z axis is greater than their stiffness along the X and Y axes, and the stiffness of the parallel beam 4 along the X and Y axes is greater than the stiffness along the Z axis. Therefore, the inner beam 6, the double-rigidity reinforced beam 5 and the flexible beam 3 are regarded as rigid, and the parallel beam 4 is regarded as flexible. The axial force Fz is transmitted to the parallel beam 4 through the four evenly distributed inner beams 6 and the flexible beam 3, forming a strain sensitive area on the parallel beam 4, thus forming a strain bridge, and then Fz can be measured.

[0042] Take the measurement of bending moment Mx as an example: the bending moment Mx is applied to the lower end face of the inner ring 7, the upper end face of the outer ring 1 is a fixed surface, and is transmitted to the parallel beam 4 through the inner beam 6. The stiffness of the flexible beam 3 and the double-rigidity reinforced beam 5 along the Z-axis direction is greater than their stiffness along the X-axis and Y-axis directions, and the stiffness of the parallel beam 4 along the X-axis and Y-axis directions is greater than the stiffness along the Z-axis direction. Therefore, the inner beam 6, the double-rigidity reinforced beam 5 and the flexible beam 3 are regarded as rigid, and the parallel beam 4 is regarded as flexible. The bending moment Mx is transmitted to the parallel beam 4 through the four evenly distributed inner beams 6 and the flexible beam 3, forming a strain sensitive area on the parallel beam 4, thus forming a strain bridge, and then Mx can be measured. Similarly, the tangential force My can be measured.

[0043] Take the measurement of torque Mz as an example: the torque Mz is applied to the lower end face of the inner ring 7, the upper end face of the outer ring 1 is a fixed face, and the stiffness of the flexible beam 3 along the length direction and along the Z-axis direction is greater than its stiffness in the thickness direction. The actual effect of the torque Mz is equivalent to a pile of equal force couples. Assuming that the directions of the two forces of the force couple are parallel to the X-axis, the inner beam 6, parallel beam 4, and flexible beam 3 whose length direction is parallel to the X-axis direction are all considered rigid, and the flexible beam 3 whose length direction is parallel to the Y-axis direction is considered flexible. At this time, the inner beam 6 parallel to the Y-axis direction is regarded as a cantilever beam. A strain sensitive area is formed on the inner beam 6, thus forming a strain bridge, and then Mz can be measured.

Claims

1. A full-plane six-dimensional force sensor elastic body, characterized in that: The elastic body comprises an outer ring (1) and an inner ring (7), wherein the outer ring (1) is sleeved on the outer side of the inner ring (7), and the outer ring (1) and the inner ring (7) are connected via four beam body components, wherein the four beam body components are equidistantly arranged between the outer ring (1) and the inner ring (7) along the circumferential direction, and one end of each beam body component is integrally formed with the outer ring (1), and the other end of each beam body component is integrally formed with the inner ring (7), and a strain measurement unit component is installed on each beam body component.

2. The full-plane six-dimensional force sensor elastic body according to claim 1, characterized in that: The elastic body also includes four double-rigidity reinforcement beams (5), each of which is located in the middle of two adjacent beam body components, and one end of each double-rigidity reinforcement beam (5) is integrally formed with the outer ring (1), and the other end of each double-rigidity reinforcement beam (5) is integrally formed with the inner ring (7).

3. The full-plane six-dimensional force sensor elastic body according to claim 2, characterized in that: The double-rigidity reinforcement beam (5) comprises four reinforcement beam bodies, which are connected end to end in sequence and arranged in a diamond shape. Two oppositely arranged tips in the double-rigidity reinforcement beam (5) are connecting parts with the outer ring (1) and the inner ring (7), one of the tips is formed integrally with the outer ring (1), and the other tip is formed integrally with the inner ring (7).

4. The full-plane six-dimensional force sensor elastic body according to claim 3, characterized in that: The beam assembly comprises an inner beam (6) and two parallel beams (4); one end of the inner beam (6) is integrally formed with an inner ring (7); the two parallel beams (4) are arranged oppositely on both sides of the other end of the inner beam (6); one end of each parallel beam (4) is integrally formed with the inner beam (6) via a flexible beam (3); the other end of each parallel beam (4) is integrally formed with an outer ring (1); each flexible beam (3) and its corresponding parallel beam (4) are located on the same center line; and each flexible beam (3) and its corresponding inner beam (6) are arranged perpendicularly.

5. The full-plane six-dimensional force sensor elastic body according to claim 4, characterized in that: The strain measurement unit assembly comprises a shear strain measurement unit (10) and two tension and compression strain measurement unit groups. The shear strain measurement unit (10) is installed on the top of the inner beam (6), and each tension and compression strain measurement unit group is correspondingly installed on the top of a parallel beam (4).

6. The full-plane six-dimensional force sensor elastic body according to claim 5, characterized in that: Each tension and compression strain measurement unit group comprises two tension and compression strain measurement units (11), and the two tension and compression strain measurement units (11) are symmetrically installed at two ends of the top of the parallel beam (4) along the center line of the length direction of the parallel beam (4).

7. The full-plane six-dimensional force sensor elastic body according to claim 6, characterized in that: The shear strain measuring unit (10) located on the inner beam (6) and the tension and compression strain measuring unit (11) located on the parallel beam (4) are both located in the same plane.

8. The full-plane six-dimensional force sensor elastic body according to claim 7, characterized in that: Six inner ring through holes (8) are processed at equal intervals on the top of the inner ring (7) along the circumferential direction, and two of the six inner ring through holes (8) are respectively arranged corresponding to two inner beams (6) arranged opposite to each other.

9. The full-plane six-dimensional force sensor elastic body according to claim 8, characterized in that: Eight outer ring through holes (2) are machined on the top of the outer ring (1) along the circumferential direction, and four of the eight outer ring through holes (2) are respectively located in correspondence with a double-rigidity reinforcement beam (5), and the other four of the eight outer ring through holes (2) are respectively arranged in correspondence with an inner beam (6).

10. The full-plane six-dimensional force sensor elastic body according to claim 9, characterized in that: The outer ring (1), the inner ring (7), the inner beam (6), the double-rigidity reinforced beam (5), the flexible beam (3) and the parallel beam (4) are all made of aluminum alloy, stainless steel or alloy steel.

Images