A universal force sensor elastomer and methods of use thereof

Abstract

The application relates to the technical field of force sensors, and discloses a universal force sensor elastic body and a use method thereof. The elastic body comprises an outer ring body and an inner ring body coaxially and spacedly sleeved, four center-symmetrically distributed connecting arms are arranged on the inner side wall of the outer ring body, the outer ring body and the inner ring body are fixedly connected through four center-symmetrically distributed deformation beams, the deformation beams and the connecting arms are circumferentially alternately arranged, each deformation beam comprises a first elastic beam shaft and a second elastic beam shaft which are perpendicular to each other, the first elastic beam shaft is connected with the inner ring body and the middle part of the second elastic beam shaft along the radial direction, the two ends of the second elastic beam shaft are connected with adjacent connecting arms respectively, and the four outer sides of the first elastic beam shaft are provided with patch surfaces. The coaxial sleeving layout shortens the axial dimension, is suitable for compact installation scenes, and can realize flexible switching of single-dimensional, two-dimensional and three-dimensional force measurement through changing the strain patch layout and bridge connection mode without replacing hardware, and has good universality.

Description

Technical Field

[0001] This invention relates to the field of force sensor technology, and specifically to a general-purpose force sensor elastomer and its usage method. Background Technology

[0002] Force sensing is a core technology for intelligent robots and precision assembly. As a structural component in force sensors that converts force into deformation, the design of the elastomer directly affects force measurement sensitivity, linearity, and interdimensional decoupling performance, thus having a decisive impact on the overall operational safety of the machine. With the deepening development of human-machine collaboration and flexible manufacturing, the need for a single sensor to achieve multidimensional force measurement within a limited space is becoming increasingly prominent.

[0003] Currently, the industry generally adopts drastically different elastomer configurations for independent design and development to meet the needs of one-dimensional, two-dimensional, and three-dimensional force measurement. Although some existing solutions propose adapting to different measurement ranges by changing the local geometry of the spoke beam, these solutions essentially involve artificially manufacturing elastomer parts of varying sizes for different needs, failing to achieve structural universality.

[0004] The same structure cannot support switching between multi-dimensional measurement modes; that is, changing the measurement dimension requires replacing the corresponding sensor hardware. When the user's application scenario changes, requiring a switch from single-dimensional force measurement to two-dimensional or three-dimensional force measurement, the entire sensor elastomer must be replaced because the physical structure itself is not reusable. This not only significantly increases manufacturing costs and inventory management difficulties, hindering the standardization and serialization of products, but also means that in the compact space where the distance between the power output end and the load end is narrow, traditional structures cannot flexibly accommodate multi-dimensional force measurement needs with a single component, making it difficult to meet the requirements of modern equipment for high integration and high flexibility. Summary of the Invention

[0005] In view of this, the present invention provides a universal force sensor elastomer and its method of use to solve the problems mentioned in the background art.

[0006] In a first aspect, the present invention provides a universal force sensor elastomer, comprising: An outer ring body and an inner ring body are coaxially spaced together. The outer ring body is provided with a plurality of power end connection holes arranged in a ring array for connecting to the power output end. The inner ring body is provided with a plurality of load end connection holes arranged in a ring array for connecting to the load end. The inner ring wall of the outer ring body is provided with four centrally symmetrically distributed connecting arms; the outer ring body and the inner ring body are fixedly connected by four centrally symmetrically distributed deformation beams, and the four deformation beams and the four connecting arms are arranged alternately in the circumferential direction. Each of the deformable beams includes a first elastic beam shaft and a second elastic beam shaft arranged perpendicularly to each other. The first elastic beam shaft extends radially along the inner ring body. A first end of the first elastic beam shaft is fixedly connected to the outer peripheral wall of the inner ring body, and a second end of the first elastic beam shaft is fixedly connected to the middle part of the second elastic beam shaft. The two ends of the second elastic beam shaft are respectively fixedly connected to two adjacent connecting arms, and the extension direction of the second elastic beam shaft is perpendicular to the extension direction of the first elastic beam shaft. Both the first elastic beam shaft and the second elastic beam shaft are cuboid structures, and the four outer sides of the first elastic beam shaft are respectively provided with patch surfaces for attaching strain gauges.

[0007] Beneficial Effects: The universal force sensor elastomer provided by this invention, through the coaxially spaced outer and inner rings, allows the force transmission paths at the power output end and load end to overlap axially and stagger radially, effectively shortening the total axial length of the sensor. This enables the elastomer to adapt to compact installation scenarios where the distance between the power output end and the load end is small. Four centrally symmetrically distributed deformation beams and four connecting arms are arranged alternately in the circumferential direction. Each deformation beam consists of a first elastic beam axis and a second elastic beam axis that are perpendicular to each other. The first elastic beam axis connects the inner ring and the middle of the second elastic beam axis radially, and the second elastic beam axis connects two adjacent connecting arms tangentially. This force transmission topology with orthogonal radial and tangential axes ensures that a load in any spatial direction can produce a identifiable strain distribution on the four deformation beams. The first elastic beam axis is a cuboid structure with patch surfaces on all four outer sides. This provides ample surface and spatial options for flexibly arranging strain gauges according to different measurement modes. This allows the same elastic body to achieve single-dimensional, two-dimensional, and three-dimensional force measurement by changing the strain gauge placement and bridging method without replacing any hardware. This solves the problem of having to replace the corresponding sensor hardware when changing the measurement dimension in traditional solutions, achieving structural universality, reducing manufacturing costs and control difficulty, and facilitating the standardization and serialization of force sensor products.

[0008] In some embodiments, a first gradually expanding curved surface transition portion is provided at the connection between the first end of the first elastic beam shaft and the inner ring body, a second gradually expanding curved surface transition portion is provided at the connection between the second end of the first elastic beam shaft and the second elastic beam shaft, and a third gradually expanding curved surface transition portion is provided at the connection between the two ends of the second elastic beam shaft and the connecting arm, respectively. The first gradually expanding curved surface transition portion, the second gradually expanding curved surface transition portion and the third gradually expanding curved surface transition portion all extend smoothly outward along the outer edge of their respective connection portions.

[0009] Beneficial Effects: First, second, and third progressively expanding curved surface transition sections are respectively provided at the connections between the first elastic beam shaft and the inner ring, the first elastic beam shaft and the second elastic beam shaft, and the connections between both ends of the second elastic beam shaft and the connecting arms. Each transition section smoothly extends outward along the outer edge of the connection. This design increases the stress-bearing cross-sectional area of ​​the connection and effectively disperses stress concentration. When the elastic body is under load, the root of the deformable beam is usually the area with the highest stress. If the stress here exceeds the material's yield limit, it will cause the elastic body to undergo plastic deformation or even fracture. Through the smooth transition design of the progressively expanding curved surface, the stress flow lines smoothly diffuse outward at the connection, avoiding stress peak concentration caused by geometrical abrupt changes. While ensuring sufficient strain response in the sensitive area of ​​the deformable beam, it effectively improves the fatigue strength and load-bearing capacity of each connection, extends the service life of the sensor under repeated loading conditions, and enhances the overall operational safety of the device.

[0010] In some embodiments, the connecting arm is a notched ring structure, the connecting arm extends in an arc shape, the center of the connecting arm is concentric with the center of the inner ring body, and the connecting arm extends circumferentially along the inner ring wall of the outer ring body and connects to the inner ring wall of the outer ring body.

[0011] Beneficial effects: The connecting arm extends in an arc shape, with its center concentric with the center of the inner ring, and extends circumferentially along the inner ring wall of the outer ring, connecting to the inner ring wall of the outer ring. This design allows the connecting arm to not only serve as a rigid connection node between the deformable beam and the outer ring, but also to transmit the constraint force from the outer ring to both ends of the second elastic beam axis in a circumferentially uniform manner through its continuous arc-shaped extension, avoiding uneven stress distribution caused by concentrated constraints in local areas. The open end design of the notched ring structure provides necessary clearance space for the small deformation of the deformable beam under external load, avoiding additional constraints imposed by the connecting arm itself on the free deformation of the deformable beam, thus ensuring the linear relationship between the strain output of the deformable beam and the applied load, which is beneficial to improving the measurement linearity of the sensor.

[0012] In some embodiments, a fixing block is provided on the inner wall of the connecting arm facing the inner ring body. The fixing block protrudes along the arc surface of the connecting arm. A first gap is left between the fixing block and the outer peripheral wall of the inner ring body. The first gap is used to limit the radial displacement limit of the inner ring body relative to the outer ring body.

[0013] Beneficial Effects: This invention features a fixing block on the inner wall of the connecting arm facing the inner ring. This fixing block protrudes along the arc surface of the connecting arm and has a first gap between it and the outer peripheral wall of the inner ring. This design provides the elastomer with radial overload protection. Within the normal operating load range, the first gap remains open, and the fixing block and inner ring do not contact each other, thus not interfering with the strain output of the deformed beam under normal stress. However, when the elastomer suffers an accidental impact or an excessive radial load, the inner ring experiences excessive radial displacement relative to the outer ring. When this displacement reaches the design value of the first gap, the outer peripheral wall of the inner ring will abut against the fixing block, thereby limiting and preventing the inner ring from continuing to move in that direction, effectively preventing the deformed beam from yielding or breaking due to excessive deformation. This overload protection design is simple and reliable, contributing to the stability of the sensor's operation.

[0014] In some embodiments, a connecting block is further provided on the inner ring wall of the outer ring body. The connecting block and the connecting arm are arranged at intervals in the circumferential direction. The connecting block is located on the side of the second elastic beam axis away from the first elastic beam axis. The connecting block protrudes in the direction towards the inner ring body. A second gap is left between the connecting block and the second elastic beam axis. The second gap is used to limit the deformation displacement limit of the deformable beam.

[0015] Beneficial Effects: This invention features a connecting block on the inner wall of the outer ring. The connecting block is located on the side of the second elastic beam axis away from the first elastic beam axis, protruding towards the inner ring and leaving a second gap between it and the second elastic beam axis. The connecting block and the fixing block form a complementary dual overload protection design. When the elastic body is subjected to a load in a certain direction, causing the deformed beam to bend, the side of the second elastic beam axis away from the first elastic beam axis will displace towards the connecting block. Within the normal measurement range, the second gap ensures that the connecting block and the second elastic beam axis remain in a non-contact state, not affecting the free deformation of the deformed beam. When the load exceeds the design range, the second elastic beam axis abuts against the connecting block, directly constraining further deformation of the deformed beam. Through the cooperative operation of the connecting block and the fixing block, a reliable overload protection design is formed from two aspects: overall displacement control of the inner ring and local deformation control of individual deformed beams.

[0016] In some embodiments, the connecting block is located at the midpoint between two adjacent connecting arms in the circumferential direction, the connecting block is disposed opposite to the midpoint of the second elastic beam axis in the radial direction, and the second gap is formed between the connecting block and the side of the second elastic beam axis away from the first elastic beam axis.

[0017] Beneficial effects: Since the middle part of the second elastic beam axis is the connection node with the first elastic beam axis, and it is also the area with the largest deformation displacement of the entire deformable beam under stress, setting the connecting block at the position corresponding to this area of ​​maximum displacement can achieve the most effective deformation limiting with minimal space occupation. This avoids excessively increasing the second gap size, which would lead to a delay in the limiting response, and also avoids the gap being too small, which would affect the degree of freedom of deformation within the normal working range. At the same time, the connecting block is located in the middle position of two adjacent connecting arms, so that the four connecting blocks are evenly distributed in the circumferential direction, corresponding one-to-one with the spatial position of the four deformable beams. This ensures the symmetry and consistency of the four deformable beams in terms of overload protection, and prevents premature triggering of the limit in one direction, which would lead to measurement distortion or damage due to off-center loading.

[0018] In some embodiments, the second elastic beam axis extends tangentially along the outer ring body, the extension direction of the second elastic beam axis is perpendicular to the extension direction of the first elastic beam axis, the first elastic beam axis is perpendicular to the second elastic beam axis and the intersection of the two is located at the midpoint of the second elastic beam axis, so that each of the deformable beams has a T-shaped symmetrical structure.

[0019] Beneficial effects: This T-shaped symmetrical layout ensures that when each deformation beam bears a load transmitted from the inner ring, the load, after being transferred along the first elastic beam axis to the midpoint of the second elastic beam axis, can be distributed symmetrically to both ends of the second elastic beam axis, and then evenly transmitted to the outer ring via the two connecting arms. This symmetrical force distribution path ensures that the strain distribution of the same deformation beam under stress is symmetrical about the midpoint of the second elastic beam axis, thus guaranteeing the symmetry and consistency of the output signals of the strain gauges attached to both sides of the first elastic beam axis. All four deformation beams have the same T-shaped symmetrical structure and are centrally symmetrically distributed, ensuring consistent mechanical properties of the entire elastic body in all four quadrants. This guarantees signal consistency and low interdimensional coupling during load measurement in all directions, achieving excellent decoupling performance without relying on software compensation algorithms.

[0020] In some embodiments, the power end connection hole on the outer ring body is a threaded through hole evenly distributed along the circumference, and the load end connection hole on the inner ring body is a threaded through hole evenly distributed along the circumference.

[0021] Beneficial effects: As a highly standardized and reliable interface, threaded through holes enable the power output end and the load end to achieve a fast and stable rigid connection through bolts, ensuring the gapless and highly repeatable load transmission path. On the other hand, the multiple threaded through holes evenly distributed in the circumference make the connection force evenly distributed on the ring body, avoiding the initial measurement error caused by the additional bending moment or uneven preload due to unilateral tightening.

[0022] In some embodiments, the thickness of the deformable beam is smaller than the thickness of the outer ring and the inner ring; The outer ring, the inner ring, the four connecting arms, and the four deformation beams are integrally formed.

[0023] Beneficial Effects: This invention sets the thickness of the deformation beam to be smaller than that of the outer and inner rings, making the deformation beam the area with the lowest stiffness in the entire elastomer structure and the first to undergo elastic deformation under stress. This ensures that strain can be effectively concentrated at the first elastic beam axis where the patch surface is located, guaranteeing that the sensor can output sufficient strain signals under stress. The outer ring, inner ring, four connecting arms, and four deformation beams adopt an integrated molding structure. The integrated design avoids the assembly stress, gaps, and nonlinear contact deformation introduced by bolted connections or welding in traditional split structures, ensuring the consistency of initial stiffness among the deformation beams and reducing zero drift and performance dispersion between batch products. In addition, the overall structure of the elastomer is regular in shape and has no complex internal cavities. It can be machined by conventional wire cutting or milling without the need for special processes such as EDM or additive manufacturing. This effectively controls processing costs during mass production and is beneficial to product manufacturing.

[0024] Secondly, the present invention also provides a method for using a universal force sensor elastomer, comprising the following steps: S1. Provide a multi-dimensional force sensor elastomer, with strain gauges respectively set on the four outer surfaces of the first elastic beam axis of the four deformed beams; S2. According to the target measurement mode, the strain gauges on the corresponding patch surface are grouped and connected in a diagonal bridge manner to form a Wheatstone bridge. S3. By switching signal acquisition channels or changing signal combination algorithms, the same elastic body can be switched between different target measurement modes.

[0025] Beneficial Effects: The method provided by this invention involves placing strain gauges on the four outer surfaces of the first elastic beam axis of four deformable beams. Then, according to the target measurement mode, the strain gauges on the corresponding surfaces are grouped and formed into a Wheatstone bridge in a diagonal bridging manner. Finally, the measurement mode can be flexibly switched by switching the signal acquisition channel or changing the signal combination algorithm. After all strain gauges are pre-placed on the same elastic body, subsequent steps only involve selecting the bridging method and switching the signal channel at the electrical level. The entire switching process does not involve the disassembly or replacement of hardware components. This method avoids the extended R&D cycle and increased mold costs caused by redesigning and manufacturing different structural elastic bodies. It also avoids the inventory pressure of users having to purchase multiple specifications of sensors to meet different force measurement needs in actual use. For compact installation spaces with narrow distances between the power output end and the load end, this method allows the same device to flexibly switch measurement modes according to the actual force measurement requirements of the current task without changing any mechanical interfaces or occupying additional installation space. This improves the functional adaptability and flexibility of force sensors in space-constrained scenarios, meeting the requirements of modern intelligent equipment for high integration and high flexibility. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a three-dimensional schematic diagram of the general-purpose force sensor elastomer according to an embodiment of the present invention; Figure 2 This is a schematic diagram showing the connection of multiple strain gauges in a general-purpose force sensor elastomer according to an embodiment of the present invention; Figure 3 This is a front view schematic diagram of the general-purpose force sensor elastomer according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the general-purpose force sensor elastomer according to an embodiment of the present invention; Figure 5 This is a partial schematic diagram of the general-purpose force sensor elastomer according to an embodiment of the present invention; Explanation of reference numerals in the attached figures: 1. Outer ring body; 101. Power end connection hole; 102. Connecting arm; 103. Connecting block; 104. Fixing block; 2. Inner ring body; 201. Load end connection hole; 3. Deformation beam; 301. First elastic beam shaft; 302. Second elastic beam shaft; 303. First gradually expanding curved surface transition section; 304. Second gradually expanding curved surface transition section; 305. Third gradually expanding curved surface transition section; 311. First deformation beam; 312. Second deformation beam; 313. Third deformation beam; 314. Fourth deformation beam; 4. Strain gauge. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0030] According to an embodiment of the present invention, in one aspect, a universal force sensor elastomer is provided, see [link to previous section]. Figures 1 to 3 The force sensor elastomer includes an outer ring 1, an inner ring 2, and deformation beams 3. The outer ring 1 and inner ring 2 are coaxially spaced. Four deformation beams 3 are provided, and the outer ring 1 and inner ring 2 are fixedly connected by four centrally symmetrically distributed deformation beams 3. The four deformation beams 3 are symmetrically distributed along the circumference of the inner ring 2 at an included angle of 90°, and the four deformation beams 3 have the same structural dimensions. The four deformation beams are designated as the first deformation beam 311, the second deformation beam 312, the third deformation beam 313, and the fourth deformation beam 314.

[0031] See Figure 3 The outer ring body 1 has multiple power end connection holes 101 arranged in a ring array for connecting the power output end; the inner ring body 2 has multiple load end connection holes 201 arranged in a ring array for connecting the load end. The inner ring wall of the outer ring body 1 has four centrally symmetrically distributed connecting arms 102; the four deformable beams 3 and the four connecting arms 102 are arranged alternately in the circumferential direction.

[0032] See Figure 2 and Figure 4Each deformable beam 3 includes a first elastic beam shaft 301 and a second elastic beam shaft 302 arranged perpendicularly to each other. The first elastic beam shaft 301 extends radially along the inner ring body 2, and its first end is fixedly connected to the outer peripheral wall of the inner ring body 2. The second end of the first elastic beam shaft 301 is fixedly connected to the middle of the second elastic beam shaft 302. The two ends of the second elastic beam shaft 302 are respectively fixedly connected to two adjacent connecting arms 102, and the extension direction of the second elastic beam shaft 302 is perpendicular to the extension direction of the first elastic beam shaft 301. Both the first elastic beam shaft 301 and the second elastic beam shaft 302 are cuboid structures, and the four outer surfaces of the first elastic beam shaft 301 are respectively provided with a mounting surface for attaching strain gauges 4.

[0033] The universal force sensor elastomer provided by the present invention, through the layout of the outer ring 1 and the inner ring 2 coaxially spaced, makes the force transmission paths of the power output end and the load end overlap in the axial direction and staggered in the radial direction, effectively shortening the total axial length of the sensor, so that the elastomer can be adapted to compact installation scenarios with a small distance between the power output end and the load end.

[0034] Four centrally symmetrically distributed deformation beams 3 and four connecting arms 102 are arranged alternately in the circumferential direction. Each deformation beam 3 is composed of a first elastic beam axis 301 and a second elastic beam axis 302 that are perpendicular to each other. The first elastic beam axis 301 connects the inner ring body 2 and the middle of the second elastic beam axis 302 radially. The second elastic beam axis 302 connects the two adjacent connecting arms 102 tangentially. This force transmission topology with radial and tangential biaxial orthogonality makes it possible for loads in any spatial direction to produce a identifiable strain distribution on the four deformation beams 3. The first elastic beam shaft 301 is a cuboid structure with patch surfaces on all four outer sides. This provides ample surface and spatial options for the flexible arrangement of strain gauges 4 according to different measurement modes. This allows the same elastic body to achieve single-dimensional, two-dimensional, and three-dimensional force measurement by changing the placement and bridging method of the strain gauges 4 without replacing any hardware. This solves the problem that traditional solutions require replacing the corresponding sensor hardware when changing the measurement dimension, achieving structural universality, reducing manufacturing costs and control difficulty, and facilitating the standardization and serialization of force sensor products.

[0035] In a specific embodiment, the thickness of the deformation beam 3 is smaller than that of the outer ring 1 and the inner ring 2; the outer ring 1, the inner ring 2, the four connecting arms 102, and the four deformation beams 3 are integrally formed. This invention sets the thickness of the deformation beam 3 to be smaller than that of the outer ring 1 and the inner ring 2, making the deformation beam 3 the area with the lowest stiffness in the entire elastic structure and the first to undergo elastic deformation under stress. This ensures that strain can be effectively concentrated at the first elastic beam axis 301 where the patch surface is located, guaranteeing that the sensor can output sufficient strain signals under stress. The outer ring 1, the inner ring 2, the four connecting arms 102, and the four deformation beams 3 are integrally formed. This integrated design avoids the assembly stress, gaps, and nonlinear contact deformation introduced by bolted connections or welding in traditional split structures, ensuring the initial stiffness consistency among the deformation beams 3 and reducing zero drift and performance dispersion between batch products. In addition, the elastomer has a regular overall structure with no complex internal cavities. It can be machined by conventional wire cutting or milling without the need for special processes such as electrical discharge machining or additive manufacturing. This can effectively control processing costs during mass production and is beneficial to product manufacturing.

[0036] The thickness, width, height, length of the four deformable beams 3 and the hollow dimensions between the first elastic beam shaft 301 and the second elastic beam shaft 302 are specifically adjusted adaptively according to the target measurement range and sensitivity, so as to adjust the stiffness distribution under load in each direction and achieve mechanical decoupling.

[0037] In a preferred embodiment, both the outer ring 1 and the inner ring 2 are made of high-strength metal materials, such as aluminum alloy or titanium alloy, which have high elastic limit and fatigue resistance, ensuring that the elastomer maintains stable mechanical properties under long-term reciprocating stress conditions. Both the outer ring 1 and the inner ring 2 are annular structures. The axial thickness of the inner ring 2 is the same as that of the outer ring 1. The radial width of the outer ring 1 is 1.2 to 1.8 times the radial width of the inner ring 2, and the axial thickness of the outer ring 1 is 2 mm to 8 mm.

[0038] In a preferred embodiment, the deformable beam 3 and the connecting arm 102 are integrally formed from the same high-strength metal material as the outer ring 1 and the inner ring 2 to ensure material consistency throughout the entire elastic body and avoid additional thermal stress caused by temperature changes due to differences in the coefficients of thermal expansion between different materials. The cross-sections of the first elastic beam shaft 301 and the second elastic beam shaft 302 are both rectangular. The axial thickness of the first elastic beam shaft 301 is 0.5 mm to 3 mm, and its radial width is 1 mm to 5 mm. The axial thickness of the second elastic beam shaft 302 is the same as that of the first elastic beam shaft 301, and its tangential width is 0.8 to 1.2 times the radial width of the first elastic beam shaft 301.

[0039] In a specific embodiment, see Figure 5 A first gradually expanding curved surface transition portion 303 is provided at the connection between the first end of the first elastic beam shaft 301 and the inner ring body 2. A second gradually expanding curved surface transition portion 304 is provided at the connection between the second end of the first elastic beam shaft 301 and the second elastic beam shaft 302. A third gradually expanding curved surface transition portion 305 is provided at the connection between the two ends of the second elastic beam shaft 302 and the connecting arm 102. The first gradually expanding curved surface transition portion 303, the second gradually expanding curved surface transition portion 304 and the third gradually expanding curved surface transition portion 305 all extend smoothly outward along the outer edge of their respective connection parts.

[0040] A first gradually expanding curved surface transition section 303, a second gradually expanding curved surface transition section 304, and a third gradually expanding curved surface transition section 305 are respectively provided at the connection between the first elastic beam shaft 301 and the inner ring body 2, the connection between the first elastic beam shaft 301 and the second elastic beam shaft 302, and the connection between both ends of the second elastic beam shaft 302 and the connecting arm 102. Each transition section smoothly extends outward along the outer edge of the connection. This design increases the stress-bearing cross-sectional area of ​​the connection and effectively disperses stress concentration. When the elastic body is subjected to load, the root of the deformable beam 3 is usually the area with the greatest stress. If the stress here exceeds the material yield limit, it will cause the elastic body to undergo plastic deformation or even fracture. Through the smooth transition design of the gradually expanding curved surface, the stress flow lines smoothly diffuse outward at the connection, avoiding the stress peak concentration caused by geometrical abrupt changes. While ensuring that the sensitive area of ​​the deformable beam 3 obtains sufficient strain response, it effectively improves the fatigue strength and load-bearing capacity of each connection, extends the service life of the sensor under repeated loading conditions, and improves the operational safety of the whole machine.

[0041] The radii of curvature of the first gradually expanding curved surface transition section 303, the second gradually expanding curved surface transition section 304, and the third gradually expanding curved surface transition section 305 are all between 0.5 mm and 3 mm. The radii of curvature of each transition section can be adaptively adjusted according to the thickness of the deformed beam 3. The radii of curvature of the transition section are positively correlated with the thickness of the deformed beam 3, that is, the larger the thickness of the deformed beam 3, the larger the radii of curvature of the transition section, so as to ensure that the stress is uniformly transferred at each connection part.

[0042] In a specific embodiment, see Figure 3 The connecting arm 102 is a notched ring structure, extending in an arc shape. The center of the connecting arm 102 is concentric with the center of the inner ring body 2. The connecting arm 102 extends circumferentially along the inner ring wall of the outer ring body 1 and connects to the inner ring wall of the outer ring body 1. Specifically, the notched ring structure is an incomplete ring with an arc-shaped opening, and the central angle corresponding to the connecting arm 102 is 60° to 100°.

[0043] The connecting arm 102 extends in an arc shape, with its center concentric with the center of the inner ring 2, and extends circumferentially along the inner ring wall of the outer ring 1, connecting to the inner ring wall of the outer ring 1. This design allows the connecting arm 102 to not only serve as a rigid connection node between the deformable beam 3 and the outer ring 1, but also to transmit the constraint force from the outer ring 1 to both ends of the second elastic beam shaft 302 in a circumferentially uniform manner through its continuous arc-shaped extension, avoiding uneven stress distribution caused by concentrated constraints in local areas. The open end design of the notched ring structure provides necessary clearance space for the small deformations of the deformable beam 3 under external loads, preventing the connecting arm 102 itself from imposing additional constraints on the free deformation of the deformable beam 3. This ensures a linear relationship between the strain output of the deformable beam 3 and the applied load, which is beneficial for improving the measurement linearity of the sensor.

[0044] In a specific embodiment, see Figure 3 A fixing block 104 is provided on the inner wall of the connecting arm 102 facing the inner ring body 2. The fixing block 104 protrudes along the arc surface of the connecting arm 102. A first gap is left between the fixing block 104 and the outer peripheral wall of the inner ring body 2. The first gap is used to limit the radial displacement limit of the inner ring body 2 relative to the outer ring body 1.

[0045] This invention features a fixing block 104 on the inner wall of the connecting arm 102 facing the inner ring 2. The fixing block 104 protrudes along the arc surface of the connecting arm 102 and has a first gap between it and the outer peripheral wall of the inner ring 2. This design provides the elastomer with radial overload protection. Within the normal operating load range, the first gap remains open, and the fixing block 104 does not contact the inner ring 2, thus not interfering with the strain output of the deformable beam 3 under normal stress. However, when the elastomer suffers an accidental impact or an excessive radial load, the inner ring 2 experiences excessive radial displacement relative to the outer ring 1. When this displacement reaches the design value of the first gap, the outer peripheral wall of the inner ring 2 will abut against the fixing block 104, thereby limiting and preventing the inner ring 2 from continuing to move in that direction, effectively preventing the deformable beam 3 from yielding or breaking due to excessive deformation. This overload protection design is simple and reliable, contributing to the stability of the sensor's operation.

[0046] In a preferred embodiment, the fixing block 104 and the connecting arm 102 are integrally formed. The fixing block 104 protrudes from the inner wall of the connecting arm 102 toward the inner ring body 2. The side end face of the fixing block 104 facing the inner ring body 2 is an arc-shaped surface that matches the curvature of the outer peripheral wall of the inner ring body 2. The radius of curvature of the arc-shaped surface is the same as the radius of curvature of the outer peripheral wall of the inner ring body 2, so that it can form a surface contact with the outer peripheral wall of the inner ring body 2 when it comes into contact, avoiding local crushing or stress concentration caused by point contact.

[0047] In a specific embodiment, see Figure 3A connecting block 103 is also provided on the inner ring wall of the outer ring body 1. The connecting block 103 and the connecting arm 102 are arranged at intervals in the circumferential direction. The connecting block 103 is located on the side of the second elastic beam shaft 302 away from the first elastic beam shaft 301. The connecting block 103 protrudes towards the inner ring body 2. A second gap is left between the connecting block 103 and the second elastic beam shaft 302. The second gap is used to limit the deformation displacement limit of the deformable beam 3.

[0048] This invention provides a connecting block 103 on the inner ring wall of the outer ring body 1. The connecting block 103 is located on the side of the second elastic beam shaft 302 away from the first elastic beam shaft 301, protruding towards the inner ring body 2, and leaving a second gap between it and the second elastic beam shaft 302. The connecting block 103 and the fixing block 104 form a complementary double overload protection design. When the elastic body is subjected to a load in a certain direction, causing the deformation beam 3 to bend, the side of the second elastic beam shaft 302 away from the first elastic beam shaft 301 will displace towards the connecting block 103. Within the normal measurement range, the second gap ensures that the connecting block 103 and the second elastic beam shaft 302 remain in a non-contact state, without affecting the free deformation of the deformation beam 3. When the load exceeds the design range, the second elastic beam shaft 302 abuts against the connecting block 103, directly constraining further deformation of the deformation beam 3. Through the cooperation of connecting block 103 and fixing block 104, a reliable overload protection design is formed from two aspects: overall displacement control of inner ring 2 and local deformation control of individual deformation beam 3.

[0049] In a preferred embodiment, the connecting block 103 and the outer ring body 1 are integrally formed. The connecting block 103 protrudes from the inner ring wall of the outer ring body 1 toward the inner ring body 2. The end face of the connecting block 103 facing the second elastic beam shaft 302 is a plane. This plane is parallel to and opposite to the side of the second elastic beam shaft 302 away from the first elastic beam shaft 301, so that it can form a plane contact with the side of the second elastic beam shaft 302 when it abuts, thereby improving the uniformity of force during the limiting.

[0050] In a specific embodiment, the connecting block 103 is located at the middle position between two adjacent connecting arms 102 in the circumferential direction, and the connecting block 103 is arranged opposite to the middle position of the second elastic beam shaft 302 in the radial direction. The second gap is formed between the connecting block 103 and the side of the second elastic beam shaft 302 away from the first elastic beam shaft 301.

[0051] Since the middle part of the second elastic beam shaft 302 is the connection node with the first elastic beam shaft 301, and is also the area with the largest deformation displacement of the entire deformable beam 3 under stress, setting the connecting block 103 at the position corresponding to this area of ​​maximum displacement can achieve the most effective deformation limiting with minimal space occupation. This avoids excessively increasing the second gap size, which would lead to a delay in the limiting response, and also avoids the gap being too small, which would affect the degree of freedom of deformation within the normal working range. At the same time, the connecting block 103 is located in the middle position of two adjacent connecting arms 102, so that the four connecting blocks 103 are evenly distributed in the circumferential direction, corresponding one-to-one with the spatial position of the four deformable beams 3. This ensures the symmetry and consistency of the four deformable beams 3 in terms of overload protection, and prevents premature triggering of the limit in one direction, which would lead to measurement distortion or damage due to off-center loading.

[0052] In a specific embodiment, see Figure 4 The second elastic beam shaft 302 extends tangentially along the outer ring 1. The extension direction of the second elastic beam shaft 302 is perpendicular to the extension direction of the first elastic beam shaft 301. The first elastic beam shaft 301 is perpendicular to the second elastic beam shaft 302, and the intersection of the two is located at the midpoint of the second elastic beam shaft 302, so that each deformable beam 3 has a T-shaped symmetrical structure.

[0053] This T-shaped symmetrical layout ensures that when each deformation beam 3 bears a load transmitted from the inner ring 2, the load is transferred along the first elastic beam axis 301 to the midpoint of the second elastic beam axis 302, and then distributed symmetrically to both ends of the second elastic beam axis 302. From there, it is evenly transmitted to the outer ring 1 via the two connecting arms 102. This symmetrical force distribution path ensures that the strain distribution of the same deformation beam 3 under stress is symmetrical about the midpoint of the second elastic beam axis 302, thus guaranteeing the symmetry and consistency of the output signals from the strain gauges 4 attached to both sides of the first elastic beam axis 301. All four deformation beams 3 have the same T-shaped symmetrical structure and are centrally symmetrically distributed, ensuring consistent mechanical properties of the entire elastic body in all four quadrants. This guarantees signal consistency and low interdimensional coupling during load measurements in all directions, achieving excellent decoupling performance without relying on software compensation algorithms.

[0054] In a specific embodiment, the power end connection hole 101 on the outer ring 1 is a threaded through hole evenly distributed circumferentially, and the load end connection hole 201 on the inner ring 2 is a threaded through hole evenly distributed circumferentially. As a highly standardized and reliable interface type, the threaded through hole enables the power output end and the load end to achieve a quick and stable rigid connection via bolts, ensuring a gapless and highly repeatable load transmission path. Furthermore, the multiple threaded through holes evenly distributed circumferentially ensure that the connection force is evenly distributed on the ring body, avoiding initial measurement errors introduced by additional bending moments or uneven preload caused by unilateral tightening.

[0055] In a preferred embodiment, both the power end connection hole 101 and the load end connection hole 201 are countersunk threaded holes or through threaded holes. The diameter of each connection hole is a standard threaded hole from M2 to M6. The number of each connection hole is four, six, or eight, and the four, six, or eight connection holes are evenly distributed along the circumference of the outer ring body 1 or the inner ring body 2. The power end connection hole 101 and the load end connection hole 201 are staggered in the axial direction to avoid axial interference when the bolts are tightened, ensuring that the installation of the power output end and the load end does not interfere with each other.

[0056] In a specific embodiment, strain gauge 4 is a resistance strain gauge, and the substrate material of strain gauge 4 is polyimide or epoxy glass fiber. The lead wires of strain gauge 4 are two-wire or three-wire. Each strain gauge 4 is attached to the four outer surfaces of the first elastic beam shaft 301 with an adhesive, which is a cyanoacrylate adhesive or an epoxy resin adhesive. After being attached to the mounting surface, the grid length direction of each strain gauge 4 is parallel or perpendicular to the axial direction of the first elastic beam shaft 301 to sense axial strain or lateral strain respectively. Each strain gauge 4 on the four deformation beams 3 is led out through flexible wires or flexible circuit boards. Each lead wire runs along the surface of the outer ring 1 and converges to the signal processing module (not shown in the figure). The signal processing module is located on the outer wall of the outer ring 1 or on the external mounting substrate. The signal processing module has a built-in Wheatstone bridge circuit and a signal conditioning circuit, which are used to perform bridging, amplification, filtering and analog-to-digital conversion processing on the resistance change signal of the strain gauge 4.

[0057] According to an embodiment of the present invention, another aspect provides a method for using a universal force sensor elastomer, comprising the following steps: S1. Provide a multi-dimensional force sensor elastomer, and set strain gauges 4 on the four outer surfaces of the first elastic beam shaft 301 of the four deformable beams 3 respectively; specifically, the strain gauges 4 are attached according to a preset patch layout scheme. The four outer surfaces of each first elastic beam shaft 301 include an upper surface, a lower surface, a left surface and a right surface. The upper surface and the lower surface are arranged opposite each other, and the left surface and the right surface are arranged opposite each other. Each surface is used to attach strain gauges 4 in different measurement modes to sense strain signals in the corresponding direction. S2. According to the target measurement mode, the strain gauges 4 on the corresponding patch surface are grouped and connected in a diagonal bridge manner to form a Wheatstone bridge. S3. By switching signal acquisition channels or changing signal combination algorithms, the same elastic body can be switched between different target measurement modes.

[0058] In specific measurement modes and processes: When the target measurement mode is a single-dimensional force measurement mode, the corresponding strain gauge 4 layout scheme is selected for bridging based on the direction of the single force or moment to be measured; where: Specific measurement of torque M Z At that time, a strain gauge 4 is set on the left and right sides of the four deformation beams respectively, and all the strain gauges 4 on the four deformation beams are connected in a diagonal bridge manner to form a Wheatstone bridge.

[0059] Specific measured force F X At that time, a strain gauge 4 is set on the left and right sides of the first deformation beam 311 and the third deformation beam 313 respectively, and the strain gauges 4 on the first deformation beam 311 and the third deformation beam 313 are connected in a diagonal bridge manner to form a Wheatstone bridge.

[0060] Specific measured force F Y At that time, a strain gauge 4 is set on the left and right sides of the second deformation beam 312 and the fourth deformation beam 314 respectively, and the strain gauges 4 on the second deformation beam 312 and the fourth deformation beam 314 are connected in a diagonal bridge manner to form a Wheatstone bridge.

[0061] Measuring force F Z At that time, a strain gauge 4 is set on the upper and lower sides of the four deformation beams respectively, and all the strain gauges 4 on the four deformation beams are connected in a diagonal bridge manner to form a Wheatstone bridge.

[0062] When the target measurement mode is a two-dimensional force measurement mode, according to the required combination of two-dimensional forces, the strain gauges in the corresponding directions are grouped into four groups and connected in a diagonal bridge manner to form the first Wheatstone bridge and the second Wheatstone bridge; wherein: Specific measured force F Z and torque M Z In the two-dimensional combination, a strain gauge 4 is set on each of the upper, lower, left, and right sides of the four deformed beams. The strain gauges 4 on the upper and lower sides are connected in a diagonal bridge manner to form a force F for measuring force F. Z The first Wheatstone bridge, with strain gauges 4 on the left and right sides connected diagonally to form a bridge for measuring torque M. Z The second Wheatstone bridge.

[0063] Specific measured force F Z Heli F X In the two-dimensional combination, a strain gauge 4 is set on the upper and lower sides of each of the four deformable beams and connected in a diagonal bridge manner to form a force F for measuring force. Z The first Wheatstone bridge has a strain gauge 4 installed on the left and right sides of the first deformed beam 311 and the third deformed beam 313, respectively, and connected in a diagonal bridge configuration to form a bridge for measuring force F. X The second Wheatstone bridge.

[0064] Specific measured force F Z Heli FY In the two-dimensional combination, a strain gauge 4 is set on the upper and lower sides of each of the four deformable beams and connected in a diagonal bridge manner to form a force F for measuring force. Z The first Wheatstone bridge has a strain gauge 4 installed on the left and right sides of the second deformation beam 312 and the fourth deformation beam 314, respectively, and connected in a diagonal bridge configuration to form a bridge for measuring force F. Y The second Wheatstone bridge.

[0065] Specific measured force F X Heli F Y In the two-dimensional combination, a strain gauge 4 is set on the left and right sides of the four deformation beams respectively. The strain gauges 4 on the first deformation beam 311 and the third deformation beam 313 are connected in a diagonal bridge manner to form a force F for measuring force. Y The strain gauges 4 on the first Wheatstone bridge, the second deformation beam 312, and the fourth deformation beam 314 are connected in a diagonal bridge configuration to form a structure for measuring force F. X The second Wheatstone bridge.

[0066] When the target measurement mode is a three-dimensional force measurement mode, a strain gauge 4 is installed on the upper, lower, left, and right sides of the four deformed beams. The strain gauges 4 on the upper and lower sides are connected in a diagonal bridge configuration to form a structure for measuring force F. Z The strain gauges 4 on the left and right sides of the first Wheatstone bridge, the first deformation beam 311 and the third deformation beam 313, are connected in a diagonal bridge configuration to form a bridge for measuring force F. Y The strain gauges 4 on the left and right sides of the second Wheatstone bridge, the second deformation beam 312 and the fourth deformation beam 314, are connected in a diagonal bridge configuration to form a bridge for measuring force F. X The third Wheatstone bridge.

[0067] The method provided by this invention involves placing strain gauges 4 on the four outer surfaces of the first elastic beam shaft 301 of four deformable beams 3. Then, according to the target measurement mode, the strain gauges 4 on the corresponding surfaces are grouped and arranged diagonally to form a Wheatstone bridge. Finally, the measurement mode can be flexibly switched by switching the signal acquisition channel or changing the signal combination algorithm. After all the strain gauges 4 are pre-placed on the same elastomer, subsequent steps only involve selecting the bridging method and switching the signal channel at the electrical level. The entire switching process does not involve the disassembly or replacement of hardware components. This method avoids the extended R&D cycle and increased mold costs caused by redesigning and manufacturing different structural elastomers. It also avoids the inventory pressure of users having to purchase multiple specifications of sensors to meet different force measurement needs in actual use. For compact installation spaces with a narrow gap between the power output end and the load end, this method allows the same device to flexibly switch measurement modes according to the actual force measurement requirements of the current task without changing any mechanical interface or occupying additional installation space. This improves the functional adaptability and usage flexibility of force sensors in space-constrained scenarios, and meets the requirements of modern intelligent equipment for high integration and high flexibility.

[0068] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A universal force sensor elastomer, characterized in that, include: An outer ring (1) and an inner ring (2) are coaxially spaced together. The outer ring (1) is provided with a plurality of power end connection holes (101) arranged in a ring array for connecting the power output end. The inner ring (2) is provided with a plurality of load end connection holes (201) arranged in a ring array for connecting the load end. The inner ring wall of the outer ring body (1) is provided with four centrally symmetrically distributed connecting arms (102); the outer ring body (1) and the inner ring body (2) are fixedly connected by four centrally symmetrically distributed deformation beams (3), and the four deformation beams (3) and the four connecting arms (102) are arranged alternately in the circumferential direction. Each of the deformable beams (3) includes a first elastic beam shaft (301) and a second elastic beam shaft (302) arranged perpendicularly to each other. The first elastic beam shaft (301) extends radially along the inner ring body (2). The first end of the first elastic beam shaft (301) is fixedly connected to the outer peripheral wall of the inner ring body (2), and the second end of the first elastic beam shaft (301) is fixedly connected to the middle part of the second elastic beam shaft (302). The two ends of the second elastic beam shaft (302) are respectively fixedly connected to two adjacent connecting arms (102), and the extension direction of the second elastic beam shaft (302) is perpendicular to the extension direction of the first elastic beam shaft (301). Both the first elastic beam shaft (301) and the second elastic beam shaft (302) are cuboid structures. The four outer sides of the first elastic beam shaft (301) are respectively provided with a patch surface for attaching strain gauges (4).

2. The universal force sensor elastomer according to claim 1, characterized in that, A first gradually expanding curved surface transition portion (303) is provided at the connection between the first end of the first elastic beam shaft (301) and the inner ring body (2). A second gradually expanding curved surface transition portion (304) is provided at the connection between the second end of the first elastic beam shaft (301) and the second elastic beam shaft (302). A third gradually expanding curved surface transition portion (305) is provided at the connection between the two ends of the second elastic beam shaft (302) and the connecting arm (102). The first gradually expanding curved surface transition portion (303), the second gradually expanding curved surface transition portion (304) and the third gradually expanding curved surface transition portion (305) all extend smoothly outward along the outer edge of their respective connection parts.

3. The universal force sensor elastomer according to claim 1, characterized in that, The connecting arm (102) is a notched ring structure. The connecting arm (102) extends in an arc shape. The center of the connecting arm (102) is concentric with the center of the inner ring body (2). The connecting arm (102) extends circumferentially along the inner ring wall of the outer ring body (1) and connects to the inner ring wall of the outer ring body (1).

4. The universal force sensor elastomer according to claim 3, characterized in that, A fixing block (104) is provided on the inner wall of the connecting arm (102) facing the inner ring body (2). The fixing block (104) protrudes along the arc surface of the connecting arm (102). A first gap is left between the fixing block (104) and the outer peripheral wall of the inner ring body (2). The first gap is used to limit the radial displacement limit of the inner ring body (2) relative to the outer ring body (1).

5. The universal force sensor elastomer according to claim 1, characterized in that, A connecting block (103) is also provided on the inner ring wall of the outer ring body (1). The connecting block (103) and the connecting arm (102) are arranged at intervals in the circumferential direction. The connecting block (103) is located on the side of the second elastic beam shaft (302) away from the first elastic beam shaft (301). The connecting block (103) protrudes towards the inner ring body (2). A second gap is left between the connecting block (103) and the second elastic beam shaft (302). The second gap is used to limit the deformation displacement limit of the deformable beam (3).

6. The universal force sensor elastomer according to claim 5, characterized in that, The connecting block (103) is located in the middle position between two adjacent connecting arms (102) in the circumferential direction. The connecting block (103) is arranged opposite to the middle position of the second elastic beam shaft (302) in the radial direction. The second gap is formed between the connecting block (103) and the side of the second elastic beam shaft (302) away from the first elastic beam shaft (301).

7. The universal force sensor elastomer according to claim 1, characterized in that, The second elastic beam axis (302) extends tangentially along the outer ring body (1), and the extension direction of the second elastic beam axis (302) is perpendicular to the extension direction of the first elastic beam axis (301). The first elastic beam axis (301) is perpendicular to the second elastic beam axis (302), and the intersection of the two is located at the midpoint of the second elastic beam axis (302), so that each of the deformable beams (3) has a T-shaped symmetrical structure.

8. The universal force sensor elastomer according to claim 1, characterized in that, The power end connection hole (101) on the outer ring body (1) is a threaded through hole evenly distributed along the circumference, and the load end connection hole (201) on the inner ring body (2) is a threaded through hole evenly distributed along the circumference.

9. The universal force sensor elastomer according to any one of claims 1-8, characterized in that, The thickness of the deformable beam (3) is smaller than the thickness of the outer ring (1) and the inner ring (2); The outer ring (1), the inner ring (2), the four connecting arms (102) and the four deformation beams (3) are integrally formed structures.

10. A method of using a general-purpose force sensor elastomer as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Provide a multidimensional force sensor elastomer, and set strain gauges (4) on the four outer surfaces of the first elastic beam shaft (301) of the four deformable beams (3); S2. According to the target measurement mode, the strain gauges (4) on the corresponding patch surface are grouped and connected in a diagonal bridge manner to form a Wheatstone bridge. S3. By switching signal acquisition channels or changing signal combination algorithms, the same elastic body can be switched between different target measurement modes.

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