Strain generation structures and force sensor

Abstract

A strain generation structure (100), comprising: at least one strain body (110), the strain body (110) being configured to generate a strain under the action of an external force, wherein at least one relief structure (111A) is formed on the surface of the at least one strain body (110), the relief structure (111A) has a recessed portion (111A1) and a protruding portion (111A2) adjacent to the recessed portion, the protruding portion (111A2) of the at least one relief structure (111A) is provided with at least one strain gauge (112), and the strain gauge (112) is configured to sense the strain generated by the strain body (110); and the strain generation structure (100) has a reference plane (P1) perpendicular to the axis (AX1) of the strain generation structure, and each strain gauge (112) of the strain generation structure (100) is arranged parallel to the reference plane (P1). The strain generation structure (100) can attach each strain gauge (112) to a plane facilitating a machine operation, and also takes into consideration the measurement performance of a six-dimensional force sensor. Further provided are a preparation method for a strain generation structure, and a force measurement module, a force sensor and a robot.

Description

Strain generation structure and force sensor Technical Field

[0001] This invention relates to the field of force sensing technology, and in particular to a strain generating structure and a force sensor. Background Technology

[0002] With the deepening research into artificial intelligence (AI) technology, more and more platforms equipped with AI have experienced rapid development. Among them, the robotics industry, as the pinnacle of the industrial sector, has gradually become a hot topic of development and research in recent years, aided by AI technology. Humanoid robots, within the robotics industry, are the best platform for AI. The humanoid robot industry and its supporting component industries are developing rapidly and are poised to become another large-scale, platform-based, and high-value-added emerging industry, following the new energy vehicle industry.

[0003] Numerous technical challenges remain in the industrialization of humanoid robots, one of which is the development, design, and mass production of six-dimensional force sensors. Six-dimensional force sensors can collect forces and torques about the X, Y, and Z axes in space. In principle, they utilize the change in resistance of strain gauges after deformation to construct a Wheatstone bridge, collecting the voltage changes across the bridge to obtain the relationship between the output voltage and strain. Then, through calibration techniques, the relationship between the output voltage and force and / or torque can be determined.

[0004] However, due to the high technical barriers in its application scenarios, six-dimensional force sensors have not been used in the civilian sector, resulting in insufficient product usage and hindering large-scale production. Consequently, their unit price remains high. Humanoid robots possess the potential for large-scale industrialization and are geared towards the civilian market. To match the industry characteristics of humanoid robots, it is necessary to develop a novel six-dimensional force sensor. This sensor should reduce production difficulty, improve product yield, and simultaneously ensure the performance and technical specifications of the six-dimensional force sensor.

[0005] Summary of the Invention

[0006] Based on this, the present invention aims to provide an improved strain generation structure and force sensor to solve at least one of the above problems.

[0007] In a first aspect, this application provides a strain generating structure, including at least one strainer configured to generate strain under the action of an external force;

[0008] In this embodiment, at least one of the strained bodies has at least one uneven structure formed on its surface, the uneven structure having a recess and a protrusion adjacent to the recess, and at least one strain gauge is provided on the protrusion of at least one of the uneven structures, the strain gauge being configured to sense the strain occurring in the strained body;

[0009] Furthermore, the strain generating structure has a reference plane perpendicular to its axis, and each strain gauge of the strain generating structure is arranged parallel to the reference plane.

[0010] The aforementioned strain generation structure has two advantages. First, by aligning all strain gauges parallel to the reference plane, subsequent patching processes can be completed by machine, significantly reducing production difficulty and improving the production efficiency and yield of the six-dimensional force sensor. Second, by forming a concave-convex structure on the surface of the strain gauge, different stress distributions are achieved at the concave and convex parts of the structure when external force is applied. This results in smaller strain on strain gauges near the concave parts and larger strain on strain gauges further away from the concave parts. In this case, the strain gauge located on the convex part of the structure can obtain a certain amount of usable strain and output an electrical signal with a certain strength. This helps to ensure the detection performance of the six-dimensional force sensor while aligning all strain gauges parallel to the reference plane.

[0011] Secondly, this application provides a strain generating structure, comprising: at least one strain type configured to generate strain under the action of an external force; wherein at least one strain type has at least one target surface perpendicular to an axis of the strain generating structure, at least one target surface is formed with at least one recess and at least one strain gauge is provided in a non-recessed portion, the strain gauge being configured to sense the strain generated by the strain type; and, the strain gauge is not provided on the non-target surfaces of each strain type.

[0012] The aforementioned strain generation structure has two advantages. First, strain gauges are only placed on the non-recessed portion of the target surface where the strain is perpendicular to the axis of the strain generation structure, while no strain gauges are placed on the non-target surfaces. This allows for machine-based subsequent patching processes, significantly reducing production difficulty and improving the production efficiency and yield of the six-dimensional force sensor. Second, by creating a recessed portion on the target surface where strain gauges are located, the strain exhibits different stress distributions at the recessed and non-recessed locations when external force is applied. Consequently, the strain near the recessed portion is smaller, while the strain further away is larger. At this point, the strain gauges on the target surface outside the recessed portion can obtain a certain degree of usable strain, thereby outputting an electrical signal with a certain strength. This is beneficial for ensuring the detection performance of the six-dimensional force sensor while all strain gauges are placed on the target surface.

[0013] Thirdly, this application provides a strain generating structure, including a first rigid body, a second rigid body, and at least one strain type connected between the first rigid body and the second rigid body, the strain type being configured to generate strain under the action of an external force; wherein the strain type, and a portion of the first rigid body and a portion of the second rigid body connected to the strain type together form a path for transmitting force and / or torque between the first rigid body and the second rigid body, at least one recess is formed on at least one of the paths and at least one strain gauge is provided in a non-recessed portion; wherein the strain gauge is located on the strain type and is configured to sense the strain generated by the strain type; the strain generating structure has a reference plane perpendicular to its axis, and each strain gauge of the strain generating structure is arranged parallel to the reference plane.

[0014] The aforementioned strain generation structure, on the one hand, arranges all strain gauges parallel to the reference plane, thus enabling the subsequent patching process to be completed by machine, significantly reducing production difficulty and improving the production efficiency and product yield of the six-dimensional force sensor; on the other hand, by forming at least one recess in the path used to transmit the force and / or torque between the first and second rigid bodies and placing at least one strain gauge in the non-recessed portion, the strain generated by the strain gauge near the recessed portion is smaller, while the strain generated by the strain gauge far from the recessed portion is larger. At this time, the strain gauge located outside the recessed portion can obtain a certain degree of usable strain and thus output an electrical signal with a certain strength. This is beneficial to ensure the detection performance of the six-dimensional force sensor while all strain gauges are arranged parallel to the reference plane.

[0015] Fourthly, this application provides a strain generating structure, comprising: at least one strain type including a strain beam configured to generate strain under external force; wherein at least one recess is formed on the surface of at least one strain type and at least one strain gauge is provided in a non-recessed portion, each strain gauge being disposed on the strain beam and configured to sense the strain generated by the strain beam; and the recess satisfies the following relationship: 0.001H≤D≤0.8H, A≥W, where D represents the depth of the recess, A represents the width of the recess, H represents the height of the strain beam, and W represents the width of the strain beam; and the strain generating structure has a reference plane perpendicular to its axis, and each strain gauge of the strain generating structure is disposed parallel to the reference plane.

[0016] The aforementioned strain generation structure, on the one hand, arranges all strain gauges parallel to the reference plane, allowing for machine-based subsequent patching processes, significantly reducing production difficulty and improving the production efficiency and yield of the six-dimensional force sensor; on the other hand, by forming recesses on the surface of the strain beams where the strain gauges are located, and ensuring that these recesses satisfy the aforementioned relationship, the strain distribution differs between the recessed and non-recessed locations when external force is applied. Consequently, the strain beams near the recesses experience smaller strains, while those far from the recesses experience larger strains. Strain gauges located outside the recesses can then obtain a certain degree of usable strain, thereby outputting an electrical signal of a certain strength. This approach helps ensure the detection performance of the six-dimensional force sensor while maintaining the parallel arrangement of each strain gauge to the reference plane.

[0017] Fifthly, this application provides a method for preparing a strain generating structure, wherein the strain generating structure includes at least one strain body, a first rigid body connected to one end of the strain body, and a second rigid body connected to the end of the strain body away from the first rigid body;

[0018] The preparation method includes: forming at least one through groove in a substrate to form a first rigid body and a second rigid body spaced apart, and at least one strained body connecting the first rigid body and the second rigid body; thinning a portion of the strained body to form at least one concave-convex structure; attaching all strain gauges parallel to a reference plane to the protrusion of at least one concave-convex structure; wherein the strain gauges are configured to sense the strain generated by the strained body, and the reference plane is perpendicular to the axis of the strain generating structure.

[0019] The above-mentioned method for fabricating the strain generating structure, on the one hand, can significantly reduce the difficulty of patching by attaching all strain gauges parallel to a reference plane to the strain body, thereby improving the production efficiency and product yield of the six-dimensional force sensor; on the other hand, by thinning a portion of the strain body to form a concave-convex structure on the surface of the strain body with strain gauges, the strain body has different stress distributions at the concave and convex positions of the concave-convex structure when external force is applied. This results in smaller strain on the strain body near the concave part and larger strain on the strain body far from the concave part. At this time, the strain gauge located on the convex part of the concave-convex structure can obtain a certain degree of usable strain and output an electrical signal with a certain strength. This is beneficial to ensure the detection performance of the six-dimensional force sensor while setting each strain gauge parallel to the reference plane.

[0020] In a sixth aspect, this application provides a force detection module, including any of the strain generating structures as described above and a measurement circuit coupled to each of the strain gauges in the strain generating structure, the measurement circuit being configured to measure the direction and magnitude of the force and / or torque acting on the strain generating structure based on electrical signals from at least one of the strain gauges.

[0021] In a seventh aspect, this application provides a force sensor, including any of the force detection modules described above.

[0022] Eighthly, this application provides a robot, including a force sensor as described above, disposed at at least one joint position of the robot or at the position of a robotic arm or mechanical lever. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 is a top view of a strain generating structure according to an embodiment of this application;

[0025] Figure 2 is a side view of a first type of concave-convex structure according to an embodiment of this application;

[0026] Figure 3 is a side view of a second type of concave-convex structure according to an embodiment of this application;

[0027] Figure 4 is a side view of a third type of concave-convex structure according to an embodiment of this application;

[0028] Figure 5 is a side view of a fourth type of concave-convex structure according to an embodiment of this application;

[0029] Figure 6 is a side view of a combined recess according to an embodiment of this application;

[0030] Figure 7 is a top view of a strain generating structure according to another embodiment of this application;

[0031] Figure 8 is a side view of a combined protrusion according to an embodiment of this application;

[0032] Figure 9 is a reference plan view of an embodiment of this application;

[0033] Figure 10 is a schematic diagram of various orthographic projections on a reference plane according to an embodiment of this application;

[0034] Figure 11 is a top view of a strain generating structure according to another embodiment of this application;

[0035] Figure 12 is a side view of a strain body according to an embodiment of this application;

[0036] Figure 13 is a structural schematic diagram of a specific embodiment of this application;

[0037] Figure 14 shows the deformation of the strain beam in the strain generating structure of Specific Embodiment 1 when subjected to a force / moment parallel to the XY plane;

[0038] Figure 15 shows the deformation of the strain beam in the strain generating structure of Specific Embodiment 1 when subjected to a force / moment perpendicular to the XY plane;

[0039] Figure 16 is a structural schematic diagram of a specific embodiment two of this application;

[0040] Figure 17 is a side view schematic diagram of various variations of the strain beam of optional embodiment three of this application;

[0041] Figure 18 is a schematic diagram of the type and connection type of the resistance strain gauge in optional embodiment four of this application;

[0042] Figure 19 is a top view of a strain generating structure according to another embodiment of this application;

[0043] Figure 20 is an enlarged schematic diagram of part K in Figure 19;

[0044] Figure 21 is a schematic diagram of the structure of a PCB board according to an embodiment of this application;

[0045] Figure 22 is a schematic diagram of the binding wires of a force detection module according to an embodiment of this application. Detailed Implementation

[0046] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0049] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0050] In the process of realizing this invention, the inventors discovered the following problems with traditional six-dimensional force sensors:

[0051] 1. Low production efficiency and low yield: The elastic body component of a six-dimensional force sensor is used to bear multi-dimensional forces and torques and transfer deformation to the resistance strain gauges through a beam structure. It is the core part of the mechanical structure design of a six-dimensional force sensor. The elastic body component has evolved to various structures, such as T-beam, four-beam, eight-beam, E-membrane, and three-beam structures. Among them, the three-beam structure has advantages such as structural stability, low processing difficulty, and miniaturization, and has gradually become the mainstream application structure in current commercial products. However, the current three-beam structure requires resistance strain gauges to be attached to all four sides of each strain beam. The resistance strain gauges on opposite sides of each strain beam are connected in series to form a half-bridge. The resistance strain gauges on the sides must be attached manually, resulting in low production efficiency and low yield.

[0052] 2. Low product compatibility: Currently, most commercially available six-dimensional force sensors use silicon-based semiconductor materials as the substrate for resistance strain gauges. Silicon-based semiconductor materials have advantages such as high tensile strength, high sensitivity coefficient, and stable properties. However, the difficulty lies in the high processing and production difficulty, which requires the use of chip slicing, photolithography, etching, and vapor deposition processes. Therefore, the resistance strain gauges used in current six-dimensional force sensors are mostly mass-produced products purchased externally. These products are all single resistors with low integration and long axial dimensions, resulting in poor compatibility with six-dimensional force sensor products.

[0053] Based on the above problems, this application proposes a novel six-dimensional force sensor design through the following inventive concept: First, each strain gauge on the elastic body component is attached to a flat surface that facilitates machine operation; second, the structure of the elastic body component is improved so that when an external force is introduced, the elastic body component can generate strain on the attachment surface of the strain gauges that is sufficient to be utilized by the bridge circuit constructed by the strain gauges; finally, the strain formed on the attachment surface of the strain gauges under the influence of external force has a definite trend of change.

[0054] Based on the aforementioned inventive concept, this application provides an improved strain generation structure. By arranging all strain gauges parallel to a reference plane, subsequent patching processes can be completed by machine, significantly reducing production difficulty and improving the production efficiency and product yield of the six-dimensional force sensor. In addition, by forming a concave-convex structure on the surface of the strain gauge, when an external force is applied, the strain gauge has different stress distributions at the concave and convex positions of the concave-convex structure. This results in smaller strain on strain gauges near the concave portion and larger strain on strain gauges far from the concave portion. At this time, the strain gauge located on the convex portion of the concave-convex structure can obtain a certain degree of usable strain and output an electrical signal with a certain strength. This is beneficial to ensure the detection performance of the six-dimensional force sensor while arranging each strain gauge parallel to the reference plane.

[0055] As shown in Figures 1 and 2, this application embodiment provides a strain generating structure 100, including at least one strain gauge 110, which is configured to generate strain under the action of an external force; wherein, at least one uneven structure 111A is formed on the surface of the at least one strain gauge 110, the uneven structure 111A having a recess 111A1 and a protrusion 111A2 adjacent to the recess 111A1, and at least one strain gauge 112 is provided on the protrusion 111A2 of the at least one uneven structure, the strain gauge 112 being configured to sense the strain generated by the strain gauge 110; and, the strain generating structure 100 has a reference plane P1 perpendicular to its axis AX1, and each strain gauge 112 of the strain generating structure 100 is arranged parallel to the reference plane P1.

[0056] For example, in the concave-convex structure 111A, the concave portion 111A1 represents a recessed area on the surface of the strained body 110, and the convex portion 111A2 represents a raised area on the surface of the strained body 110 relative to the concave portion 111A1. For example, referring to Figures 2 to 5, it can be seen that the height of any point on the bottom or side surface of the concave portion 111A1 is lower than the height of any point on the top surface of the convex portion 111A2, and without a boundary, the concave portion 111A1 can extend in a direction away from the convex portion 111A2, and the convex portion 111A2 can extend in a direction away from the concave portion 111A1. Optionally, as shown in Figure 3, the side and bottom surfaces of the recess 111A1 are both flat surfaces, and the side surface of the recess 111A1 is set at an angle to the reference surface P1. The included angle α between these two surfaces can be greater than 0° and less than 180°. In particular, when the included angle is 90°, the recess 111A1 and the convex part 111A2 form a concave-convex structure as shown in Figure 2. Optionally, as shown in Figure 4, the surface of the recess 111A1 can also be a curved surface. Optionally, the surface of the recess 111A1 and the surface of the convex part 111A2 are smoothly connected. In this case, at least one of the surfaces of the recess 111A1 and the convex part 111A2 is a curved surface. As shown in Figure 5, the surfaces of the recess 111A1 and the convex part 111A2 are both curved surfaces and are smoothly connected. Optionally, the concave-convex structure can also be a notch formed on the edge of the strain 110 (not shown in the figure). By forming a recess 111A1 on the surface of at least one strain gauge 110, a more concentrated stress distribution can be formed in the strain gauge 110 corresponding to the recess 111A1 when an external force is introduced. As a result, the strain on the protrusion near the recess 111A1 is less than the strain on the protrusion 111A2 away from the recess 111A1. At this time, the strain gauge 112 provided on the protrusion 111A2 can obtain a certain degree of usable strain of the strain gauge 110, and then output a voltage signal through the bridge circuit, and make the output voltage change proportionally to the stress on the strain structure 100.

[0057] For example, at least one convex-concave structure has a plurality of strain gauges disposed on its convex portion, wherein at least two strain gauges are disposed at intervals. Distantly disposing of at least two strain gauges facilitates the detection of forces and moments in different directions. Optionally, taking Figure 1 as an example, the surface of the strain gauge 110 in the lower right corner has at least one convex-concave structure 111A, and the convex portion 111A2 of 111A is disposed at intervals with two strain gauges 112 in a direction perpendicular to the radial direction of the strain generating structure 100. This facilitates full utilization of the lateral space of the strain gauge 110 and reduces the volume of the strain generating structure 100. Of course, as shown in Figure 7, the surface of the strain gauge 110 in the lower right corner has at least one convex-concave structure 111A, and the convex portion 111A2 of 111A may also be disposed at intervals with two strain gauges 112 in a radial direction of the strain generating structure 100.

[0058] For example, as shown in Figures 1 and 6, when the surface of the strain gauge 110 has multiple concave and convex structures, the recesses 111A1 of at least a pair of adjacent concave and convex structures 111A can be connected or integrally formed into a combined recess with convex portions on both sides, and at least one strain gauge is disposed on the convex portion on one or both sides of at least one combined recess. Referring to Figure 6, it can be seen that the two sides of the combined recess are respectively bounded by the convex portions 111A2 of the two concave and convex structures 111A, thereby defining the length of the combined recess. Optionally, as shown in Figure 7, the combined recess can be a first groove 111 that runs through the surface of the strain gauge 110, or a second groove 114 that forms an opening on the surface of the strain gauge 110. Optionally, continuing to refer to Figure 7, it can be seen that the two side walls of the second groove 114 have a first arc structure, which helps to avoid stress concentration, allowing more stress to be transferred to the strain gauge 110, and also helps to improve the overload resistance of the strain generating structure 100.

[0059] Furthermore, as shown in Figures 7 and 8, when the surface of the strain gauge 110 has multiple combined recesses, the protrusions between at least one pair of adjacent combined recesses can be connected or integrally formed into a combined protrusion 113, and at least two strain gauges 112 are spaced apart on the combined protrusion 113. This facilitates the detection of forces and moments in different directions, and also allows the strain gauges 112 to obtain more usable strain, thereby improving the detection accuracy of the six-dimensional force sensor. Furthermore, at least two strain gauges 112 are sequentially spaced apart on the combined protrusion 113 along the arrangement direction of the pair of combined recesses. This facilitates the full utilization of the strain distribution brought about by the combined recesses, enabling effective detection of forces and moments; simultaneously, this arrangement allows the strain gauge 110 to be made narrower, making it easier for the strain gauge 110 to undergo strain and facilitating the measurement of smaller forces and / or moments. For example, referring to Figure 8, it can be seen that the two sides of the combined protrusion 113 are respectively bounded by combined recesses 111 and 114, thereby defining the length of the combined protrusion 113. In addition, the term "integral formation" as used in this application can mean integral molding.

[0060] For example, strain gauge 112 may include one or more Wheatstone bridges. When multiple Wheatstone bridges are included, their distribution can be arbitrary or irregular, such as vertically or horizontally. The Wheatstone bridge can be a full-bridge circuit, a half-bridge circuit, or a quarter-bridge circuit. When the Wheatstone bridge is a full-bridge circuit, a larger output voltage can be obtained. Specifically, when the Wheatstone bridge is a half-bridge circuit, a full-bridge circuit can be constructed by combining it with the circuits and resistors on the six-dimensional force sensor circuit board, or a half-bridge circuit can be used directly without construction. When the Wheatstone bridge is a quarter-bridge circuit, a full-bridge circuit or a half-bridge circuit can be constructed by combining it with the circuits and resistors on the six-dimensional force sensor circuit board, or a quarter-bridge circuit can be used directly without construction.

[0061] For example, a Wheatstone bridge can be composed of several resistance strain gauges. Structurally, the resistance strain gauges can include at least one of a single-cell resistance strain gauge, a half-bridge resistance strain gauge, and a full-bridge resistance strain gauge. The integration density of a full-bridge resistance strain gauge is greater than that of a half-bridge resistance strain gauge, and the integration density of a half-bridge resistance strain gauge is greater than that of a single-cell resistance strain gauge. Higher integration density of the strain gauges is more advantageous for meeting the space-constrained, high-accuracy installation requirements of six-dimensional force sensors. Specifically, a single-cell resistance strain gauge includes a resistor and upper and lower pads connected to opposite ends of the resistor, respectively; a half-bridge resistance strain gauge includes two resistors connected in series via a middle pad and upper and lower pads connected to opposite ends of the two series-connected resistors, respectively; a full-bridge resistance strain gauge includes two half-bridge resistance strain gauges connected in series via bridging pads. Therefore, "strain gauges set parallel to the reference plane" can be expressed as the distribution surface of each resistor in the strain gauge being parallel to the reference plane. Furthermore, since each resistor in the strain gauge is set on the convex part of the concave-convex structure, this further ensures that the forming surface of the concave part and the setting surface of the strain gauge are the same surface, thus balancing the detection performance of the six-dimensional force sensor with the requirement for a fully planar setup of the strain gauge. On the other hand, when using highly integrated resistance strain gauges (half-bridge or full-bridge resistance strain gauges) for full-bridge assembly, both the consistency of resistance values ​​and the elimination of the influence of temperature on the measurement can be guaranteed. Combined with the subsequent same-surface printing and adhesive application process, the adhesive thickness at different target locations can be ensured to further reduce the error of the full-bridge circuit, thereby greatly improving the detection accuracy of the six-dimensional force sensor.

[0062] In some embodiments of this application, as shown in Figures 9 and 10, the strain generating structure 100 has a reference plane P2 parallel to the external force input end face of the strainer 110. The external force input end face 115 of the strainer, which has at least one concave-convex structure, has a first orthographic projection S1 on the reference plane P2. The cross-section of the strainer 110 corresponding to the concave portion 111A1 of the at least one concave-convex structure 111A has a second orthographic projection S2 on the reference plane P2. The first orthographic projection S1 covers the second orthographic projection S2. This is beneficial to ensure that the stress distribution on the strain gauge mounting surface after the external force is transmitted to the strainer 110 is affected by the concave portion 111A1, forming a stress distribution (strain distribution) with low stress (low strain) near the concave portion 111A1 and high stress (high strain) far from the concave portion 111A1. If the first orthographic projection S1 does not cover the second orthographic projection S2, it will easily affect the stress distribution on the strain gauge mounting surface, thereby affecting the detection accuracy of the six-dimensional force sensor. Furthermore, as shown in Figures 9 and 10, the cross-section of the strain 110 corresponding to the protrusion 111A2 of at least one concave-convex structure 111A has a third orthographic projection S3 on the reference plane P2, and the first orthographic projection S1 covers the third orthographic projection S3. Since the second orthographic projection S2 of the cross-section of the strain 110 corresponding to the concave portion 111A1 on the reference plane P2 is significantly smaller than the third orthographic projection S3 of the cross-section of the strain 110 corresponding to the protrusion 111A2 on the reference plane P2, by having the third orthographic projection S3 covered by the first orthographic projection S1, it is beneficial to further ensure the strain distribution brought about by the concave portion 111A1 when an external force is introduced.

[0063] In some embodiments of this application, continuing to refer to FIG1, the recess depth of the recess 111A1 of the concave-convex structure 111A is less than or equal to a first preset value. In principle, as the recess depth of the recess 111A increases, the small strain area on the surface of the strained body 110 gradually increases, eventually leading to insufficient available strain on the convex body 111A2. Therefore, the recess depth of the recess 111A1 has an upper limit (i.e., the first preset value) to avoid an excessively large small strain area formed on the surface of the strained body 110. Optionally, the recess depth represents the height difference between the lowest point of the recess and the lowest point of the convex body in a concave-convex structure. Optionally, the recess depth D of the recess 111A can be determined based on the height of the strained body 110 (i.e., the thickness of the strained body 110 along the z-direction). Optionally, as shown in FIG1, when a combined recess 111 is formed on the strained body 110, the width of the combined recess 111 can be determined based on the width of the strained body 110, where the width represents the length perpendicular to the radial direction of the strain generating structure 100.

[0064] In some embodiments of this application, continuing to refer to FIG1, in at least one strain gauge 112, the distance between the resistance of the recess 111A1 closest to the corresponding concave-convex structure 111A and the recess 111A1 is less than or equal to a second preset value. This ensures that the resistance in the strain gauge 112 is not too far from the recess 111A1, guaranteeing that the resistance of the recess 111A1 closest to the corresponding concave-convex structure 111A is located in a small strain region formed on the surface of the strain gauge 110, thereby ensuring that the strain gauge 112 obtains a certain degree of usable strain and achieves effective detection of force and torque.

[0065] In some embodiments of this application, continuing to refer to FIG1, in at least one strain gauge 112, the distance between the resistance of the recess 111A1 furthest from the corresponding concave-convex structure 111A and the recess 111A1 is greater than or equal to a third preset value. Influenced by the recess 111A1, the strain on the surface of the strain gauge 110 decreases towards the recess 111A1 and increases towards the distance from the recess 111A1. Thus, the above arrangement ensures that the resistance of the recess 111A1 furthest from the corresponding concave-convex structure 111A is located in a large strain region formed on the surface of the strain gauge 110, thereby ensuring that the strain gauge 112 obtains a certain degree of usable strain and achieves effective detection of force and torque.

[0066] In some embodiments of this application, referring to FIG7, the strain gauge 110 has a concave-convex structure 111A and a concave-convex structure 111B, and at least one strain gauge 112 is provided on the combined protrusion 113 formed by connecting or integrally forming the protrusions of the two; wherein, at least one resistor of the at least one strain gauge 112 is at a distance from the center of the combined protrusion 113 less than or equal to a fourth preset value. Since at least one strain gauge 112 is provided on the combined protrusion 113 (located between the two concave parts), the strain in the central region of the combined protrusion 113 is the largest when an external force is transmitted to the strain gauge 110. Thus, the above arrangement ensures that at least one resistor of the strain gauge 112 is located in the central region of the combined protrusion 113 with the largest strain, thereby ensuring that the strain gauge 112 obtains a certain degree of usable strain and realizing effective detection of force and torque.

[0067] In some embodiments of this application, the strain gauge 110 has a first surface and a second surface that are opposite to and parallel to the reference plane P1. The first surface and / or the second surface are formed with at least one concave-convex structure. At least one strain gauge 112 is provided on the protrusion 111A2 of at least one concave-convex structure 111A of each strain gauge 110. In this way, it is beneficial to make full use of the strain distribution brought about by the concave portion 111A1, increase the number of strain gauges 112, thereby further improving the detection accuracy of the six-dimensional force sensor, while also meeting the requirement of full-plane arrangement of strain gauges 112, improving production efficiency and product yield.

[0068] In some embodiments of this application, referring to Figures 1 and 7, the strain generating structure further includes: a first rigid body 120 connected to one end of the strained body 110; a second rigid body 130 connected to the end of the strained body 110 away from the first rigid body 120; and at least one through groove 140 formed between the first rigid body 120 and the second rigid body 130, alternating with the strained body 110 along the circumferential direction of the strain generating structure 100; wherein, when the force and / or torque between the first rigid body 120 and the second rigid body 130 is transmitted to the strained body 110, the strained body 110 undergoes strain. Optionally, the first rigid body 120 may be connected to an external fastener, and the second rigid body 130 may be connected to an external loading element, ensuring that there is no coupling between the first rigid body 120 and the second rigid body 130 when no applied force is applied. Thus, by applying force to the first rigid body 120 and the second rigid body 130, a relative motion tendency can be generated between the first rigid body 120 and the second rigid body 130, thereby transmitting the force and / or torque between the first rigid body 120 and the second rigid body 130 to the strained body 110, causing the strained body 110 to undergo strain.

[0069] Optionally, the first rigid body 120, each strain type 110, and the second rigid body 130 are integrally formed. Optionally, an elastic material can be used as the matrix material for the strain generating structure 100. Optionally, the elastic material can be one of stainless steel, aerospace aluminum, or titanium alloy. In this way, on the one hand, the aforementioned elastic material can ensure the sensitivity of strain sensing, and on the other hand, the integrally formed structure is also conducive to ensuring the overload resistance of the strain generating structure 100. In addition, when stainless steel is used for fabrication, the manufacturing cost of the strain generating structure 100 is lower than that of aerospace aluminum and titanium alloy, thus facilitating the industrialization of six-dimensional force sensors. It is understood that the first rigid body 120, each strain type 110, and the second rigid body 130 can also be independent components, connected to form the strain generating structure 100.

[0070] Optionally, the through groove 140 has a first groove wall in the first rigid body 120 and a second groove wall in the second rigid body 130; wherein at least a portion of the contour of the second groove wall matches the contour of at least a portion of the first groove wall. Thus, no destructive interference will occur between the first and second groove walls under overload conditions, thereby improving the overload resistance of the strain generating structure 100 and extending the service life of the six-dimensional force sensor.

[0071] Optionally, the strain gauge 110 includes an elastic structure and a strain beam connected to the elastic structure; wherein one end of the elastic structure is connected to a first rigid body, the other end away from the first rigid body is connected to the strain beam, and the end of the strain beam away from the elastic structure is connected to a second rigid body; wherein at least one protrusion of at least one concave-convex structure of at least one strain body is located on the strain beam. The elastic structure can be a thin plate-like structure, thus functioning as a floating beam, i.e., when the strain generating structure 100 is subjected to external force, it generates bending deformation to reduce interdimensional interference of the six-dimensional force sensor. Therefore, introducing an elastic structure helps to improve the measurement accuracy and stability of the sensor. Optionally, the strain gauge also includes a first connecting portion connecting the strain beam to the elastic structure, and a second connecting portion connecting the strain beam to the second rigid body. Thus, the concave-convex structure on the strain gauge 110 can be provided on at least one of the first connecting portion, the strain beam, and the second connecting portion, ensuring that the protrusion of at least one concave-convex structure is located on the strain beam. This ensures that the stress distribution (strain distribution) caused by the concave portion of the concave-convex structure when external force is introduced can be formed on the strain beam and thus sensed by the strain gauge.

[0072] Optionally, a notch is provided through the elastic structure. The side of the elastic structure away from the first rigid body 120 extends radially inward along the strain generating structure 100 and connects to the strain beam. By providing the notch, it is beneficial to block the outward transmission path of stress, causing it to concentrate more on the strain beam, thereby increasing the available strain of the strain gauge 112 and improving the detection performance of the six-dimensional force sensor.

[0073] Optionally, a smooth and continuous second arc structure is provided at the connection position between the first rigid body 120 and the elastic structure; and / or, a smooth and continuous third arc structure is provided at the connection position between the elastic structure and the strain beam; and / or, a smooth and continuous fourth arc structure is provided at the connection position between the strain beam and the second rigid body 130. By providing the above-mentioned arc structures, it is beneficial to avoid stress concentration at the connection positions of various components, so that more stress is transferred to the strain beam, increasing the available strain, and also improving the overload resistance of the strain generating structure 100.

[0074] Optionally, the first rigid body 120 and the second rigid body 130 are located at different heights along the axis of the strain generating structure 100. This facilitates the formation of a cavity for accommodating the circuit board.

[0075] Optionally, as shown in Figure 7, a through hole 131 can be provided in the central region of the second rigid body 130. This facilitates the internal wiring of the robotic arm and robot, enabling concealed wiring. If internal wiring is not required, the through hole can be filled, adopting a via-less solution.

[0076] Optionally, the first rigid body 120 has a first assembly portion connected to the first object, and the second rigid body 130 has a second assembly portion connected to the second object, wherein the force and / or torque between the first object and the second object are transmitted to the strain generating structure 100 through the first and second assembly portions. With the above arrangement, the strain generating structure 100 can be coupled to an external object to receive external force input. Optionally, the assembly portion can be a threaded hole, a slot, etc. Optionally, the first object can be the upper protective housing of a six-dimensional force sensor or a flange bolt of a robotic arm / robot, and the second object can be the lower protective housing of a six-dimensional force sensor or a flange bolt of a robotic arm / robot.

[0077] Based on the foregoing inventive concept, this application embodiment also provides another improved strain generating structure 200, as shown in Figures 11 and 12, comprising: at least one strain gauge 110', configured to generate strain under external force; wherein, the at least one strain gauge 110' has at least one target surface 116 perpendicular to the axis AX2 of the strain generating structure 200, the at least one target surface 116 having at least one recess 111' and at least one strain gauge 112 provided in the non-recessed portion, the strain gauge 112 being configured to sense the strain generated by the strain gauge 110'; and, no strain gauge 112 is provided on the non-target surface of each strain gauge 110'.

[0078] The strain generating structure 200 described above has two advantages. First, strain gauges 112 are only installed on the non-recessed portion of the target surface where the strain gauge 110' is perpendicular to the axis AX2 of the strain generating structure 200. Strain gauges 112 are not installed on non-target surfaces. This allows the subsequent patching process to be completed by machine, significantly reducing production difficulty and improving the production efficiency and product yield of the six-dimensional force sensor. Second, by forming a recessed portion on the target surface where the strain gauges 112 are installed, the strain gauge 110' has different stress distributions at the recessed portion 111' and non-recessed portion when external force is applied. This results in smaller strain on the strain gauge 110' near the recessed portion 111' and larger strain on the strain gauge 110' far from the recessed portion 111'. At this time, the strain gauges 112 located on the target surface outside the recessed portion 111' can obtain a certain degree of usable strain and output an electrical signal with a certain strength. This is beneficial to ensure the detection performance of the six-dimensional force sensor while all strain gauges 112 are installed on the target surface.

[0079] In some embodiments of this application, at least one target surface is formed with a plurality of recesses 111', and at least two strain gauges 112 are spaced apart on the target surface between at least one pair of adjacent recesses 111'. This is beneficial for detecting forces and moments in different directions, and also allows the strain gauges 112 to obtain more usable strain, thereby improving the detection accuracy of the six-dimensional force sensor.

[0080] In some embodiments of this application, the side of at least one recessed portion 111' is angled to the surface of the non-recessed portion; or, the surface of at least one recessed portion 111' is curved; or, the surface of at least one recessed portion 111' is smoothly connected to the surface of the non-recessed portion.

[0081] In some embodiments of this application, continuing to refer to FIG11, the strain gauge 110' has a first target surface 116 and a second target surface 117 that are opposite to each other and perpendicular to the axis AX2 of the strain generating structure 200; wherein, the first target surface 116 has at least one recess 111' and at least one strain gauge 112 is provided in the non-recessed portion; and / or, the second target surface 117 has at least one recess 111' and at least one strain gauge 112 is provided in the non-recessed portion. This facilitates full utilization of the strain distribution brought about by the recess 111A1, increases the number of strain gauges 112, thereby further improving the detection accuracy of the six-dimensional force sensor, and also meets the requirement of full-plane arrangement of the strain gauges 112, improving production efficiency and product yield.

[0082] In some embodiments of this application, the strain generating structure 200 has a reference plane (not shown in the figure, similar to reference plane P2) parallel to the external force input end face of the strain gauge 110'. The external force input end face of the strain gauge 110', which has at least one recess 111', has a fourth orthographic projection onto the reference plane. The cross-section of the strain gauge 110' corresponding to the at least one recess 111' has a fifth orthographic projection onto the reference plane, and the fourth orthographic projection covers the fifth orthographic projection. This is beneficial to ensure that the stress distribution on the strain gauge mounting surface after the external force is transmitted to the strain gauge 110 is affected by the recess 111', forming a stress distribution (strain distribution) with low stress (low strain) near the recess 111' and high stress (high strain) far from the recess 111'. If the fourth orthographic projection does not cover the fifth orthographic projection, it can easily affect the stress distribution on the strain gauge mounting surface, thereby affecting the detection accuracy of the six-dimensional force sensor.

[0083] Based on the aforementioned inventive concept, as shown in FIG13, this application embodiment also provides another improved strain generating structure 1, including a first rigid body 2, a second rigid body 6, and at least one strain variant connected between the first rigid body 2 and the second rigid body 6, the strain variant being configured to generate strain under the action of an external force;

[0084] Among them, the strained body, and the portion of the first rigid body 2 and the portion of the second rigid body 6 connected to the strained body together form a passage R (shown by an elliptical dashed line) for transmitting the force and / or torque between the first rigid body 2 and the second rigid body 6. At least one recess is formed on at least one passage R (as shown in FIG16, a strain groove is formed on each passage R), and at least one strain gauge 5 is provided in the non-recessed portion.

[0085] Among them, the strain gauge 5 is located on the strained body and is configured to sense the strain generated by the strained body; the strain generating structure 1 has a reference plane perpendicular to its axis, and each strain gauge 5 of the strain generating structure 1 is arranged parallel to the reference plane.

[0086] The strain generation structure 1 described above has two advantages. First, by arranging all strain gauges 5 parallel to the reference plane, the subsequent patching process can be completed by machine, significantly reducing production difficulty and improving the production efficiency and product yield of the six-dimensional force sensor. Second, by forming at least one recess in the path R used to transmit the force and / or torque between the first rigid body 2 and the second rigid body 6, and placing at least one strain gauge in the non-recessed portion, the strain of strain gauges near the recessed portion is smaller, while the strain of strain gauges far from the recessed portion is larger. At this time, the strain gauges located outside the recessed portion can obtain a certain degree of usable strain and thus output an electrical signal with a certain intensity. This is beneficial to ensure the detection performance of the six-dimensional force sensor while arranging each strain gauge parallel to the reference plane.

[0087] In some embodiments of this application, continuing to refer to FIG13, a recess (i.e., a second strain groove 9) is formed on the second rigid body 6 in the passage R. This facilitates the miniaturization of the strain generating structure 1, thereby broadening the applicability of the strain generating structure 1. For example, the width of the second strain groove 9 (i.e., the length perpendicular to the radial direction of the strain generating structure 1) is greater than the width of the strain beam 3.

[0088] In some embodiments of this application, continuing to refer to FIG13, at least two recesses (such as a first strain groove 8 and a second strain groove 9) are provided at intervals along the extension direction of at least one passage R, and at least two strain gauges 5 are provided between at least one pair of adjacent recesses along the extension direction of the passage R. This is beneficial for detecting forces and moments in different directions, and also allows the strain gauges 112 to obtain more usable strain, thereby improving the detection accuracy of the six-dimensional force sensor.

[0089] Based on the aforementioned inventive concept, as shown in Figures 19 and 20, this application embodiment also provides another improved strain generating structure 300, comprising: at least one strain gauge 110', including a strain beam 118, the strain beam 118 being configured to generate strain under external force; wherein, at least one recess 111' is formed on the surface of at least one strain gauge 112 is provided in the non-recessed portion, each strain gauge 112 is provided on the strain beam 118 and is configured to sense the strain generated by the strain beam 118; and, the recess 111' satisfies the following relationship: 0.001H≤D≤0.8H, A≥W, where D represents the depth of the recess 111', A represents the width of the recess 111', H represents the height of the strain beam 118, and W represents the width of the strain beam 118; and, the strain generating structure has a reference plane P3 perpendicular to its axis AX3, each strain gauge 112 of the strain generating structure 300 being arranged parallel to the reference plane P3.

[0090] The strain generation structure 300 described above has two advantages. First, by setting all strain gauges 112 parallel to the reference plane P3, the subsequent patching process can be completed by machine, significantly reducing production difficulty and improving the production efficiency and product yield of the six-dimensional force sensor. Second, by forming a recess 111' on the surface of the strain gauge 110' on which the strain gauges 112 are set, and by making the recess 111' satisfy the above-mentioned relationship, the strain gauge 110 has different stress distributions at the recess 111' and non-recessed locations when external force is introduced. This results in smaller strain on the strain beam 118 near the recess 111' and larger strain on the strain beam 118 far from the recess 111'. At this time, the strain gauges 112 located at non-recessed locations can obtain a certain degree of usable strain and output an electrical signal with a certain strength. This is beneficial to ensure the detection performance of the six-dimensional force sensor while setting each strain gauge 112 parallel to the reference plane P3.

[0091] For example, the depth D of at least one recess 111' can be one of 0.001H, 0.01H, 0.1H, 0.2H, 0.4H, 0.6H, or 0.8H. The size of the depth D will affect the range of the small strain region on the strain beam 118.

[0092] In some embodiments of this application, referring to FIG20, strain gauge 112 also satisfies the following relationship: 0 < P ≤ 0.4L, where P represents the distance between strain gauge 112 and the edge of recess 111', and L represents the length of strain beam 118; and / or, strain gauge 112 satisfies the following relationship: 0 < Q ≤ 0.4W, where Q represents the distance between strain gauge 112 and the side edge of strain beam 118. Exemplarily, P can be one of 0.05L, 0.1L, 0.2L, 0.3L, and 0.4L. Exemplarily, Q can be one of 0.05W, 0.1W, 0.2W, 0.3W, and 0.4W. In principle, the smaller the values ​​of P and Q, the better; on the other hand, excessively large values ​​of P and Q will lead to a decrease in the signal output strength of the bridge arm of the Wheatstone bridge.

[0093] The inventive concept and effects of this application will be further illustrated below through two specific embodiments.

[0094] Specific Implementation Example 1

[0095] As shown in Figure 13, the strain generating structure 1 is fabricated from a single cylindrical metal substrate and includes a first rigid body 2, a second rigid body 6, an elastic structure 4, and a strain beam 3. One end of the elastic structure 4 is connected to the first rigid body 2, and the other end, away from the first rigid body 2, is connected to the strain beam 3. The end of the strain beam 3, away from the elastic structure 4, is connected to the second rigid body 6. Thus, the first rigid body 2 and the second rigid body 6 are completely connected through the elastic structure 4 and the strain beam 3. The strain generating structure 1 has three elastic structures 4 and three strain beams 3. All three strain beams 3 are polyhedral beam structures. The first rigid body 2 is connected to each of the three elastic structures 4. Each elastic structure 4 extends inward into a "T-shaped" structure. The three strain beams 3 are connected to the "T-shaped" structures extending from the elastic structures 4. The three strain bodies formed by the strain beams 3 and the elastic structures 4 can be evenly distributed along the circumference of the strain generating structure 1 or form non-uniform angles.

[0096] Three through slots 12 are formed between the first rigid body 2 and the second rigid body 6. These three through slots 12 are either evenly distributed or at non-uniform angles. The first rigid body 2 and the second rigid body 6 are located at different heights along the axis of the strain generating structure 1, forming cavities with the elastic structures 4 and strain beams 3 to accommodate the PCB board. The first rigid body 2 is the outer rigid body structure of the six-dimensional force sensor, used to transmit forces and / or torques from the positive Z-axis connecting parts. The force transmission path is from the first rigid body 2 to the elastic structure 4, and then to the top of the strain beam 3. The second rigid body 6 is the inner rigid body structure of the six-dimensional force sensor, used to transmit forces and / or torques from the negative Z-axis connecting parts. The force transmission path is from the second rigid body 6 to the bottom of the strain beam 3. Therefore, the strain of the three strain beams 3 can characterize the force condition of the six-dimensional force sensor. In this specific embodiment, the second rigid body 6 and the strain beam 3, the elastic structure 4 and the strain beam 3, and the elastic structure 4 and the first rigid body 2 all have continuous arc structures, which helps to avoid stress concentration and improve the overload resistance of the strain generating structure 1. The second rigid body 6 in this specific embodiment has a central through-hole 10, which is used for internal wiring of the robotic arm, enabling concealed wiring for the robotic arm and humanoid robot. If internal wiring is not required, the through-hole 10 can be filled, adopting a through-hole-free solution.

[0097] Referring again to Figure 13, a first strain groove 8 is provided at the connection between the strain beam 3 and the elastic structure 4, and a second strain groove 9 is provided at the connection between the strain beam 3 and the second rigid body 6. The first strain groove 8 and the second strain groove 9 are milled into a polygonal or shallow groove structure with rounded corners. At least one strain gauge 5 is attached between the first strain groove 8 and the second strain groove 9. The strain gauge 5 converts the strain of the strain beam 3 into an electrical signal. The strain gauge 5 and the strain beam 3 are bonded together using a non-metallic material and cured at high temperature, so that the strain of the strain beam 3 can be completely transmitted to the strain gauge 5. The function of the first strain groove 8 and the second strain groove 9 is to cause the strain of the strain beam 3 to gradually decrease near the strain groove and gradually increase away from the strain groove when the structure is under stress. Utilizing this characteristic, by constructing a bridge circuit for the strain gauge 5, the output voltage of the strain gauge 5 can be made to change proportionally with the force on the elastic body. The first strain groove 8 and the second strain groove 9 can have various application forms and appearance shapes, including but not limited to milling bosses and grooves on the upper and lower surfaces of the strain beam 3.

[0098] Figure 14 illustrates the deformation of strain beam 3 when strain generating structure 1 is subjected to a force / moment parallel to the XY plane. When the elastic body is subjected to a force / moment parallel to the XY plane, strain beam 3 is divided into strains in opposite directions along the neutral layer perpendicular to the XY plane, as shown in Figure 14. The left region of strain beam 3 is in a compressed state, and the right region is in a tensile state. At this time, the resistance of the left strain gauge of strain gauge 5 decreases, and the resistance of the right strain gauge increases. Strain beam 3 is divided into three regions: 1A, 1B, and 1C. Region 1A is close to the first strain groove 8, region 1C is close to the second strain groove 9, and region 1B is between regions 1A and 1C. Due to the action of the first strain groove 8 and the second strain groove 9, the strain in regions 1A and 1C is less than the strain in region 1B. At this time, the resistance change of the strain gauge in regions 1A and 1C is less than the resistance change of the strain gauge in region 1B. Finally, strain gauge 5 can construct a voltage output proportional to strain using the difference in resistance of the strain gauges.

[0099] Figure 15 illustrates the deformation of strain beam 3 when strain generating structure 1 is subjected to a force / moment perpendicular to the XY plane. When strain generating structure 1 is subjected to a force / moment perpendicular to the XY plane, strain beam 3 is divided into strains in opposite directions along the neutral layer parallel to the XY plane, as shown in Figure 15. The upper surface of strain beam 3 is in a tensile state, and the lower surface is in a compressive state. At this time, the resistance values ​​of the left and right strain gauges of strain gauge 5 increase synchronously. Strain beam 3 is divided into three regions: 2A, 2B, and 2C. Region 2A is close to the first strain groove 8, region 2C is close to the second strain groove 9, and region 2B is between regions 2A and 2C. Due to the action of the first strain groove 8 and the second strain groove 9, the strain in regions 2A and 2C is less than the strain in region 2B. At this time, the resistance change of the strain gauge in regions 2A and 2C is less than the resistance change of the strain gauge in region 2B. Finally, strain gauge 5 can construct a voltage output proportional to strain using the difference in resistance values ​​of the strain gauges.

[0100] Specific Implementation Example 2

[0101] As shown in Figure 16, the overall structure of Specific Embodiment Two is basically the same as that of Specific Embodiment One, except that Specific Embodiment Two has six elastic structures 4 and six corresponding strain beams 3, with each strain beam 3 corresponding to a strain groove. Specifically, referring to Figure 16, three of the six strain beams 3 are provided with first strain grooves 8, and the other three strain beams 3 are provided with second strain grooves 9. Strain gauges 5 can be attached below the first strain groove 8 or above the second strain groove 9. The strain gauges 5 convert the strain of the strain beam 3 into an electrical signal. The strain gauges 5 and the strain beam 3 are bonded together using a non-metallic material and cured at high temperature, so that the strain of the strain beam 3 can be completely transmitted to the strain gauges 5. The functions of the first strain groove 8 and the second strain groove 9 are the same as those of the strain generation structure 1 of the three-beam six-dimensional force sensor described above, and will not be repeated here.

[0102] The following will take Specific Embodiment 1 as an example to provide several optional implementation methods that can be applied to Specific Embodiment 1 and Specific Embodiment 2.

[0103] Optional Implementation Method 1

[0104] As shown in Figure 13, the elastic structure 4 has several through holes, which are connected by notched grooves 7. When the six-dimensional force sensor is subjected to a force or torque parallel to the XY plane, the strain beam 3 can be subjected to strain in the opposite direction along the neutral layer perpendicular to the XY plane.

[0105] Optional Implementation Method Two

[0106] As shown in Figure 13, the first rigid body 2 has several main threaded holes 14, through which it is bolted to the upper protective housing of the six-dimensional force sensor or directly to the flange of the robotic arm. The first rigid body 2 also has several main pin holes 15, used for the disassembly, assembly, positioning, and anti-reverse installation of the upper protective housing of the six-dimensional force sensor and the flange of the robotic arm. The second rigid body 6 has several secondary threaded holes 16, through which it is bolted to the lower protective housing of the six-dimensional force sensor or directly to the flange of the robotic arm. The second rigid body 6 also has several secondary pin holes 20, used for the disassembly, assembly, positioning, and anti-reverse installation of the lower protective housing of the six-dimensional force sensor and the flange of the robotic arm. The second rigid body 6 has several PCB mounting threaded holes 17, used to fix the PCB board to the second rigid body 6 using bolts. The external mechanical connection methods of the first rigid body 2 and the second rigid body 6 include, but are not limited to, bolted connections, and can also include snap-fit, welding, etc.

[0107] Optional Implementation Method 3

[0108] Figure 17 shows various variations of the strain beam 3 and various optional arrangements of the strain gauges 5 mounted on the strain beam 3.

[0109] As shown in Figure 17.a, the first strain groove 8 and the second strain groove 9 are both located on the upper surface of the strain beam 3. Each strain beam 3 uses one strain gauge 5, and the strain gauge 5 is attached between the first strain groove 8 and the second strain groove 9. This is the first variant of the strain beam 3. As shown in Figure 17.b, the first strain groove 8 and the second strain groove 9 are both located on the lower surface of the strain beam 3. Each strain beam 3 uses one strain gauge 5, and the strain gauge 5 is attached between the first strain groove 8 and the second strain groove 9. This is the second variant of the strain beam 3. As shown in Figure 17.c, the first strain groove 8 and the second strain groove 9 are located on the upper and lower surfaces of the strain beam 3, respectively, and both the first strain groove 8 and the second strain groove 9 are located at the top of the strain beam 3. Each strain beam 3 uses two strain gauges 5, and the strain gauges 5 are attached below the first strain groove 8 and the second strain groove 9. This is the third variant of the strain beam 3. As shown in Figure 17.d, the first strain gauge 8 and the second strain gauge 9 are located on the upper and lower surfaces of the strain beam 3, respectively, and both are located at the bottom end of the strain beam 3. Each strain beam 3 uses two strain gauges 5, which are mounted above the first strain gauge 8 and the second strain gauge 9. This is the fourth variation of the strain beam 3. As shown in Figure 17.e, the first strain gauge 8 and the second strain gauge 9 are located on the upper and lower surfaces of the strain beam 3, respectively, or the first strain gauge 8 is located on the lower surface of the strain beam 3, and the second strain gauge is located on the upper surface of the strain beam 3. The first strain gauge 8 is located at the top of the strain beam 3, and the second strain gauge 9 is located at the bottom end of the strain beam 3. Each strain beam 3 uses two strain gauges 5, which are mounted between the first strain gauge 8 and the second strain gauge 9. This is the fifth variation of the strain beam 3. As shown in Figure 17.f, the first strain gauge 8 and the second strain gauge 9 are located on the upper and lower surfaces of the strain beam 3, respectively. The first strain gauge 8 is located at both the top and bottom of the strain beam 3, and similarly, the second strain gauge 9 is located at both the top and bottom of the strain beam 3. Each strain beam 3 uses two strain gauges 5, and the strain gauges 5 are mounted between the first strain gauge 8 and the second strain gauge 9. This is the sixth variant of the strain beam 3.

[0110] Optional Implementation Method Four

[0111] Figure 18 shows a top view of various structural compositions of a resistance strain gauge. The resistance strain gauge can be a sheet-like element etched using diffused silicon.

[0112] Figure 18.a shows a single-unit resistance strain gauge 510, which consists of an upper pad 5101, a silicon wafer resistor 5102, and a lower pad 5103. The silicon wafer resistor 5102 is a stress-sensitive element, and its resistance value changes with the applied stress. The silicon wafer resistor 5102 is centrally located and connected to both the upper pad 5101 and the lower pad 5103. The single-unit resistance strain gauge 510 is electrically connected to the outside via the upper pad 5101 and the lower pad 5103. Figure 18.b shows a half-bridge resistance strain gauge 511, which consists of two single-unit resistance strain gauges 510 connected in series. The middle pad 5111 connects the two single-unit resistance strain gauges 510. The half-bridge resistance strain gauge (511) is electrically connected to the outside via the upper pad (5101), the middle pad (5111), and the lower pad 5103. Figure 18.c shows the first full-bridge strain gauge 512, which consists of two half-bridge strain gauges 511 connected in series. Generally, the first bridging pad 5121 connects the lower pads 5103 of the two half-bridge strain gauges 511 together, forming a tail-to-tail connection. In this case, the first full-bridge strain gauge 512 achieves external electrical wiring connections through the two upper pads 5101, the two middle pads 5111, and the first bridging pad 5121. Specifically, the first bridging pad 5121 can also connect the upper pads 5101 of the two half-bridge strain gauges 511 together, forming a head-to-head connection. In this case, the first full-bridge strain gauge 512 achieves external electrical wiring connections through the first bridging pad 5121, the two middle pads 5111, and the two lower pads 5103. Figure 18.d shows the second full-bridge resistance strain gauge 513, which consists of two half-bridge resistance strain gauges 511 connected in series. A second bridging pad 5131 connects the lower pad 5103 and upper pad 5101 of the two half-bridge resistance strain gauges 511, forming a head-to-tail connection. In this case, the second full-bridge resistance strain gauge 513 achieves external electrical circuit connection through an upper pad 5101, two middle pads 5111, a lower pad 5103, and a second bridging pad 5131. The first Wheatstone bridge 501 and the second Wheatstone bridge 502 can be bridged using one or more of the aforementioned resistance strain gauges.

[0113] This application also provides a method for fabricating a strain generating structure, the method comprising: forming at least one through groove in a substrate to form a first rigid body and a second rigid body spaced apart and at least one strained body connecting the first rigid body and the second rigid body; thinning a portion of the strained body to form at least one concave-convex structure; attaching all strain gauges parallel to a reference plane to the protrusion of at least one concave-convex structure; wherein the strain gauges are configured to sense the strain generated by the strained body, and the reference plane is perpendicular to the axis of the strain generating structure.

[0114] The above-described fabrication method, on the one hand, significantly reduces the difficulty of patching by attaching all strain gauges parallel to a reference plane to the strain gauge, thereby improving the production efficiency and product yield of the six-dimensional force sensor; on the other hand, by thinning a portion of the strain gauge to form a concave-convex structure on the surface of the strain gauge, the strain gauge exhibits different stress distributions at the concave and convex parts of the concave-convex structure when external force is applied. Consequently, the strain gauge near the concave part experiences smaller strain, while the strain gauge far from the concave part experiences larger strain. At this time, the strain gauge located at the convex part of the concave-convex structure can obtain a certain degree of usable strain and thus output an electrical signal with a certain strength. This is beneficial for ensuring the detection performance of the six-dimensional force sensor while setting each strain gauge parallel to the reference plane.

[0115] In some embodiments of this application, an adhesive can be used to attach the strain gauge. Optionally, the adhesive can be glue, glass powder, etc. When using glue for bonding, a printing press can be used to apply a uniform thickness of glue to the surface of the strain gauge, thereby avoiding the influence of inconsistent glue thickness on the resistance value in the bridge circuit.

[0116] This application embodiment also provides a force detection module, including any of the strain generating structures as described above and a measurement circuit coupled to each strain gauge in the strain generating structure. The measurement circuit is configured to measure the direction and magnitude of the force and / or torque acting on the strain generating structure based on electrical signals from at least one strain gauge.

[0117] For example, the strain generating structure further includes a first rigid body connected to one end of the strain body; a second rigid body connected to the end of the strain body away from the first rigid body; and at least one through slot formed between the first rigid body and the second rigid body, alternating with the strain body along the circumference of the strain generating structure; wherein the strain body undergoes strain when the force and / or torque between the first rigid body and the second rigid body is transmitted to the strain body, and the first rigid body and the second rigid body are located at different heights along the axis of the strain generating structure; the measuring circuit includes: a circuit board disposed in the cavity formed by the first rigid body, each strain body, and the second rigid body, the circuit board having wiring slots corresponding to each strain gauge, and bridging pads connected to the pads of the strain gauges being disposed near the wiring slots.

[0118] Optionally, the measurement circuit includes a PCB board, which is placed in the internal cavity of the strain generating structure to complete the acquisition, amplification, and conversion of strain electrical signals into force and torque signals, as well as to perform direction calculation.

[0119] Optionally, as shown in Figure 21, the PCB board 13 has several polygonal slots 19, each polygonal slot 19 enclosing an area corresponding to the area where the strain gauge 5 of each strain beam 3 is located. A mounting through hole 22 is provided at the connection point between the PCB board 13 and the second rigid body 6 to achieve a mechanical connection between the PCB board 13 and the second rigid body 6. A bolt through hole 21 is provided on the PCB board 13 at the position corresponding to the secondary threaded hole 16, allowing the mounting bolts of the lower protective housing or the robotic arm flange to pass through the PCB board 13, thus enabling various mechanical connection methods for the robotic arm.

[0120] Optionally, as shown in Figure 22, the PCB board 13 uses bonding technology to connect the metal wires from the pads of the strain gauge 5 to the pads of the PCB board. In this embodiment, the PCB board 13 has several bridging pads. Depending on the type of resistance strain gauge used in the first Wheatstone bridge 501 and the second Wheatstone bridge 502 on the strain gauge 5, a corresponding bonding technology is used to connect several metal wires 18 from the pads of the resistance strain gauges to the bridging pads 23 of the PCB board 13. One end of the metal wire 18 is fixed to the pad of the resistance strain gauge, and the other end is fixed to the bridging pad 23 of the PCB board 13, thereby achieving an electrical connection between the strain gauge 5 and the PCB board 13.

[0121] This application also provides a force sensor, including any of the force detection modules described above. The aforementioned force sensor helps reduce manufacturing manpower, improve production efficiency and product yield while ensuring detection accuracy, and also helps reduce size and lower production costs.

[0122] This application also provides a robot, including a force sensor as described above, located at at least one joint of the robot or at the location of a robotic arm or mechanical lever.

[0123] For example, the aforementioned robots may include at least one of the following: industrial collaborative robots, quadruped robots, transport robots, surgical robots, and humanoid robots. Examples include robotic arms used for assembly, polishing, and material handling in industrial production; remote surgery in the medical field; wind tunnel testing and space station assembly in the aerospace field; and research on robotic arm control algorithms and the development of teaching aids in education and scientific research. When a six-dimensional force sensor is installed at the wrist and ankle of a humanoid robot, it can provide mechanical data acquisition signals to assist in the force control algorithm of the humanoid robot, and is a core component in the humanoid robot assembly.

[0124] As can be seen from the above embodiments of this application, the inventive concept of this application helps to develop a six-dimensional force sensor product with high accuracy, high resolution, miniaturization, lightweight and low cost, thereby gaining broad application prospects in the field of robotics.

[0125] It should be noted that the numbers used to describe and claim certain embodiments of this application, representing quantities or properties, should be understood to be modified in some cases by the terms "approximately," "about," "approximately," or "essentially." For example, unless otherwise stated, "approximately," "about," "approximately," or "essentially" can indicate a variation of ±20% of the value they describe. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may be changed according to the characteristics required by individual embodiments. In some embodiments, numerical parameters should take into account specified significant digits and employ a general method of digit reservation. Although the numerical ranges and parameters used to confirm their breadth of range in some embodiments of this application are approximate values, in specific embodiments, such numerical values ​​are set as precisely as feasible.

[0126] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A strain-generating structure, characterized in that, include: At least one strain gauge, the strain gauge being configured to undergo strain under the action of an external force; in, At least one of the strained bodies has at least one uneven structure formed on its surface, the uneven structure having a recess and a protrusion adjacent to the recess, and at least one strain gauge is disposed on the protrusion of at least one of the uneven structures, the strain gauge being configured to sense the strain occurring in the strained body; and, The strain generating structure has a reference plane perpendicular to its axis, and each strain gauge of the strain generating structure is arranged parallel to the reference plane.

2. The strain generating structure according to claim 1, characterized in that, At least one of the protrusions of the concave-convex structure is provided with a plurality of strain gauges, wherein at least two strain gauges are arranged at intervals.

3. The strain generating structure according to claim 2, characterized in that, At least two of the strain gauges are arranged at intervals along the direction away from / near the recess of the convex-concave structure.

4. The strain generating structure according to claim 1, characterized in that, At least one strain gauge has a plurality of said concave and convex structures formed on its surface, wherein at least a pair of adjacent concave and convex structures are connected or integrally formed into a combined concave portion with convex portions on both sides, and at least one strain gauge is disposed on the convex portion on one or both sides of at least one of the combined concave portions.

5. The strain generating structure according to claim 4, characterized in that, At least one strain gauge has a plurality of said combined recesses formed on its surface, wherein each of the protrusions between at least a pair of adjacent said combined recesses is connected or integrally formed into a combined protrusion, and at least two said strain gauges are spaced apart on said combined protrusions.

6. The strain generating structure according to claim 5, characterized in that, At least two strain gauges are sequentially and spaced apart on the combined protrusion along the arrangement direction of the pair of combined recesses.

7. The strain generating structure according to any one of claims 4 to 6, characterized in that, The combined recess type includes at least one of a first groove that traverses the surface of the strained material and a second groove that forms an opening on the surface of the strained material.

8. The strain generating structure according to any one of claims 4 to 6, characterized in that, At least one side wall of the combined recess has a smooth, continuous first circular arc structure.

9. The strain generating structure according to claim 1, characterized in that, At least one strain gauge has a first surface and a second surface that are opposite to and parallel to the reference plane, the first surface and / or the second surface having at least one of the said convex-concave structures, and the convex portion of at least one of the said convex-concave structures being provided with at least one of the said strain gauges.

10. The strain generating structure according to claim 1, characterized in that, In at least one of the concave-convex structures, the side of the concave portion is angled to the reference surface; or, in at least one of the concave-convex structures, the surface of the concave portion is curved; or, in at least one of the concave-convex structures, the surface of the concave portion is smoothly connected to the surface of the convex portion.

11. The strain generating structure according to claim 1, characterized in that, The recess depth of at least one of the recesses in the concave-convex structure is less than or equal to a first preset value.

12. The strain generating structure according to claim 1, characterized in that, The strain generating structure has a reference plane parallel to the external force input end face of the strained body. The external force input end face of the strained body with at least one of the concave-convex structures has a first orthographic projection on the reference plane. The cross-section of the strained body corresponding to the concave portion of the at least one of the concave-convex structures has a second orthographic projection on the reference plane. The first orthographic projection covers the second orthographic projection.

13. The strain generating structure according to claim 12, characterized in that, The cross section of the strain body corresponding to at least one of the protrusions of the concave-convex structure has a third orthographic projection on the reference plane, wherein the first orthographic projection covers the third orthographic projection.

14. The strain generating structure according to any one of claims 1 to 6, characterized in that, The strain gauge includes at least one Wheatstone bridge, which includes at least one of a single-cell resistance strain gauge, a half-bridge resistance strain gauge, and a full-bridge resistance strain gauge. in, The single-unit resistance strain gauge includes a resistor and two terminals respectively connected to opposite ends of the resistor. Upper pad and lower pad; The half-bridge resistance strain gauge includes two resistors connected in series via a middle pad, and an upper pad and a lower pad respectively connected to the opposite ends of the two resistors connected in series. The full-bridge resistance strain gauge includes two half-bridge resistance strain gauges connected in series via bridging pads.

15. The strain generating structure according to claim 14, characterized in that, In at least one of the strain gauges, The distance between the resistor closest to the recess of the corresponding concave-convex structure and the recess is less than or equal to a second preset value, and / or the distance between the resistor furthest from the recess of the corresponding concave-convex structure and the recess is greater than or equal to a third preset value.

16. The strain generating structure according to claim 14, characterized in that, At least one of the strains has a plurality of the said concave and convex structures; Wherein, at least one pair of adjacent protrusions of the concave-convex structure are connected or integrally formed into a combined protrusion, and at least one strain gauge is provided on the combined protrusion; Wherein, at least one resistor in at least one of the strain gauges is at a distance from the center of the combined protrusion that is less than or equal to a fourth preset value.

17. The strain generating structure according to claim 1, characterized in that, The strain generating structure further includes: A first rigid body is connected to one end of the strain body; A second rigid body is connected to the end of the strained body furthest from the first rigid body; and At least one through groove is formed between the first rigid body and the second rigid body, and is alternately arranged with the strained body along the circumference of the strain generating structure; in, When the force and / or torque between the first rigid body and the second rigid body is transmitted to the strained body, the strained body undergoes strain.

18. The strain generating structure according to claim 17, characterized in that, The through groove has a first groove wall in the first rigid body and a second groove wall in the second rigid body; wherein at least a portion of the contour of the second groove wall matches the contour of at least a portion of the first groove wall.

19. The strain generating structure according to claim 17 or 18, characterized in that, The strain includes an elastic structure and a strain beam connected to the elastic structure; Wherein, one end of the elastic structure is connected to the first rigid body, the other end away from the first rigid body is connected to the strain beam, and the end of the strain beam away from the elastic structure is connected to the second rigid body; Wherein, at least one of the protrusions of the concave-convex structure of at least one strain body is located on the strain beam.

20. The strain generating structure according to claim 19, characterized in that, A smooth, continuous second arc structure is provided at the connection point between the first rigid body and the elastic structure; and / or, A smooth, continuous third circular arc structure is provided at the connection point between the elastic structure and the strain beam; and / or, A smooth and continuous fourth circular arc structure is provided at the connection position between the strain beam and the second rigid body.

21. The strain generating structure according to claim 19, characterized in that, A notch is provided through the elastic structure, and the elastic structure on the side of the notch away from the first rigid body extends radially inward along the strain generating structure and connects to the strain beam.

22. The strain generating structure according to claim 17 or 18, characterized in that, The first rigid body has a first assembly portion connected to a first object, and the second rigid body has a second assembly portion connected to a second object, wherein the force and / or torque between the first object and the second object is transmitted to the strain generating structure through the first assembly portion and the second assembly portion.

23. A strain-generating structure, characterized in that, include: At least one strain gauge, the strain gauge being configured to undergo strain under the action of an external force; in, At least one strainer has at least one target surface perpendicular to the axis of the strain generating structure, at least one target surface is formed with at least one recess and at least one strain gauge is provided in the non-recessed portion, the strain gauge being configured to sense the strain generated by the strainer; and, The strain gauges were not installed on the non-target surfaces of each strained variety.

24. The strain generating structure according to claim 23, characterized in that, At least one of the target surfaces has a plurality of said recesses, and at least two said strain gauges are spaced apart on the target surface between at least a pair of adjacent said recesses.

25. The strain generating structure according to claim 23, characterized in that, The strain generating structure has a reference plane parallel to the external force input end face of the strained body. The external force input end face of the strained body, which has at least one of the recesses, has a fourth orthographic projection on the reference plane. The cross-section of the strained body corresponding to at least one of the recesses has a fifth orthographic projection on the reference plane. The fourth orthographic projection covers the fifth orthographic projection.

26. A strain generating structure, characterized in that, It includes a first rigid body, a second rigid body, and at least one strained body connected between the first rigid body and the second rigid body, the strained body being configured to undergo strain under the action of an external force; in, The strain gauge, together with the portion of the first rigid body and the portion of the second rigid body connected to the strain gauge, forms a passage for transmitting force and / or torque between the first rigid body and the second rigid body, and at least one recess is formed on at least one of the passages and at least one strain gauge is provided in the non-recessed portion; in, The strain gauge is located on the strained body and is configured to sense the strain occurring on the strained body; The strain generating structure has a reference plane perpendicular to its axis, and each strain gauge of the strain generating structure is arranged parallel to the reference plane.

27. A strain generating structure, characterized in that, include: At least one strain type, including a strain beam, said strain beam being configured to undergo strain under the action of an external force; in, At least one of the strain gauges has at least one recessed portion formed on its surface and at least one strain gauge is provided in the non-recessed portion. Each strain gauge is provided on the strain beam and configured to sense the strain occurring in the strain beam. and, The recessed portion satisfies the following relationship: 0.001H≤D≤0.8H, A≥W, where D represents the depth of the recessed portion, A represents the width of the recessed portion, H represents the height of the strain beam, and W represents the width of the strain beam. as well as, The strain generating structure has a reference plane perpendicular to its axis, and each strain gauge of the strain generating structure is arranged parallel to the reference plane.

28. The strain generating structure according to claim 27, characterized in that, The strain gauge also satisfies the following relationship: 0 ≤ P ≤ 0.4L, where P represents the distance between the strain gauge and the edge of the recess, and L represents the length of the strain beam; and / or, The strain gauge satisfies the following relationship: 0≤Q≤0.4W, where Q represents the distance between the strain gauge and the side edge of the strain beam.

29. A method for preparing a strain-generating structure, characterized in that, The strain generating structure includes at least one strain body, a first rigid body connected to one end of the strain body, and a second rigid body connected to the end of the strain body away from the first rigid body. The preparation method includes: At least one through groove is formed in the substrate to form the first rigid body and the second rigid body spaced apart, and at least one strained body connecting the first rigid body and the second rigid body; A portion of the strained material is thinned to form at least one uneven structure; All strain gauges are attached to at least one of the protrusions of the concave-convex structure parallel to a reference plane; wherein the strain gauges are configured to sense the strain generated by the strained material, and the reference plane is perpendicular to the axis of the strain-generating structure.

30. A force detection module, characterized in that, The strain generating structure includes any one of claims 1 to 28 and a measurement circuit coupled to each of the strain gauges in the strain generating structure, the measurement circuit being configured to measure the direction and magnitude of the force and / or torque acting on the strain generating structure based on an electrical signal from at least one of the strain gauges.

31. A force sensor, characterized in that, Includes the force detection module as described in claim 30.

32. A robot, characterized in that, Includes the force sensor as described in claim 31, located at at least one joint of the robot or at the location of the robotic arm or mechanical lever.

Images