A nonlinear force sensing unit and multi-dimensional force sensor thereof

Abstract

This invention relates to the field of force sensor technology, and more particularly to a nonlinear force sensing unit and its multidimensional force sensor. It primarily addresses the problem that existing six-dimensional force sensors employ a structure combining a crossbeam and a vertical beam. The vertical beam, acting as a cantilever beam, can only be linearly calibrated and cannot compensate for nonlinear errors affecting measurement accuracy. Furthermore, the vertical beam requires mounting plates on all four sides, necessitating significant space, resulting in a large overall sensor size, a non-compact structure, and difficulty in adapting to confined installation scenarios. The proposed technical solution includes a fixed frame with elastic units disposed inside. The fixed frame is connected to a connector via the elastic units, and the fixed frame and connector are respectively connected to the fixed end and the force-bearing end. This invention enables nonlinear calibration of all force-measuring components to improve measurement accuracy, while simultaneously simplifying the mounting plate layout space, effectively reducing the overall size, achieving a miniaturized and compact sensor design, and adapting to more confined installation conditions.

Description

Technical Field

[0001] This invention relates to the field of force sensor technology, and in particular to a nonlinear force sensing unit and its multidimensional force sensor. Background Technology

[0002] A prior art invention describes a six-dimensional force sensor employing an elastic body structure combining a cross beam and a vertical beam. Strain gauges are attached to the surfaces of both the cross beam and the vertical beam, enabling the acquisition of force and torque signals in six dimensions. This structure, due to its good symmetry and clear mechanical model, is widely used in various six-dimensional force measurement scenarios. During calibration, the cross beam can be nonlinearly calibrated using appropriate algorithms, effectively compensating for nonlinear errors generated during elastic body deformation and thus improving measurement accuracy. However, the vertical beam, as a cantilever beam structure, is limited by its stress-deformation characteristics, requiring only linear calibration. This makes it difficult to effectively compensate for nonlinear errors, which is insufficient for high-precision measurement requirements and limits the overall measurement performance of the sensor to some extent.

[0003] Meanwhile, to ensure the accuracy of the measurement of each component of the six-dimensional force, strain gauges need to be attached to all four sides of the vertical beam to comprehensively capture the strain signals of the vertical beam under external forces in different directions. This requires reserving sufficient space for attaching and operating the strain gauges on the vertical beam to avoid interference during the attachment process and to ensure that the strain gauges can stably sense deformation. Due to the limitations of this attachment requirement, the distance between the two ends of the existing sensor has to be designed to be relatively long, resulting in a larger overall sensor size and a less compact structure. This makes it difficult to adapt to space-constrained installation scenarios such as robot end effectors and dexterous finger joints, which contradicts the current trend of sensor miniaturization and lightweighting and limits its widespread application in small precision equipment. Summary of the Invention

[0004] The purpose of this invention is to address the problems in the background technology where existing six-dimensional force sensors use a structure combining a cross beam and a vertical beam. The vertical beam, as a cantilever beam, can only be linearly calibrated and cannot compensate for nonlinear errors that affect measurement accuracy. Furthermore, the vertical beam requires patching on all four sides, which requires a large amount of space, resulting in a large overall size and non-compact structure of the sensor, making it difficult to adapt to narrow installation scenarios. The invention proposes a nonlinear force sensing unit and its multi-dimensional force sensor.

[0005] In a first aspect, the present invention proposes a nonlinear force sensing unit, including a fixed frame, an elastic unit disposed inside the fixed frame, a connector connected to the fixed frame through the elastic unit, the fixed frame and the connector respectively connecting to a fixed end or a force-bearing end; multiple sets of strain gauges, the strain gauges being installed on the side of the elastic unit, the elastic unit including at least three sets of elastic bodies, the multiple sets of elastic bodies being distributed in a ring array to form a single-layer nonlinear stiffness ring structure.

[0006] Optionally, one end of the elastomer is fixedly connected to the connector, and the other end of the elastomer is fixedly connected to the fixed frame.

[0007] Optionally, the fixing frame has multiple sets of mounting holes.

[0008] Optionally, at least one set of strain gauges is installed on the upper and / or lower sides of the elastomer, and the strain gauges are arranged parallel to each other or at 45° / 135° along the length of the elastomer.

[0009] Optionally, the fixing frame, elastic unit, and connector are integrally formed.

[0010] Secondly, the present invention proposes a multidimensional force sensor, comprising two sets of nonlinear force sensing units, which are connected by a connector in the form of a column, and the two sets of nonlinear force sensing units are respectively connected to a fixed end or a force-bearing end.

[0011] Optionally, the number of elastic bodies in the two sets of nonlinear force sensing units can be set independently, with the two numbers being the same or different, forming a double-layer nonlinear stiffness ring structure.

[0012] Optionally, at least one set of strain gauges may be installed on the upper and / or lower sides of the elastic body in the two sets of nonlinear force sensing units, and the strain gauges may be arranged parallel to or at 45° / 135° along the length of the elastic body.

[0013] Optionally, the strain gauge is mounted on the elastomer using glass micro-solution or adhesive curing technology.

[0014] Optionally, the two sets of nonlinear force sensing units and the connecting piece connecting them are integrally formed or fixedly connected.

[0015] In summary, this application includes at least one of the following beneficial technical effects:

[0016] This invention, through a single-layer nonlinear stiffness ring structure design, enables nonlinear calibration of all elastic bodies, effectively solving the defects of traditional vertical beam cantilever structures that can only be linearly calibrated and have nonlinear errors, and significantly improving the accuracy of six-dimensional force detection.

[0017] Furthermore, by abandoning the traditional multi-sided patch arrangement of connectors, the strain gauges are uniformly arranged on the elastic body in a ring array, eliminating the need to reserve a large amount of patch installation space and effectively shortening the overall axial dimension of the sensor; at the same time, the integrated layout of inner and outer double-layer elastic units with a ring fixing frame, combined with the one-piece molded structure, greatly reduces the overall space occupied, making it suitable for various narrow installation conditions and with a wider range of applications.

[0018] Furthermore, by relying on two sets of independent elastic units to complete the acquisition of six-dimensional force signals, all force-measuring elastic bodies can be uniformly calibrated nonlinearly, which completely solves the drawback that the connectors in traditional structures can only be calibrated linearly, effectively reducing measurement errors; at the same time, different numbers of elastic bodies can be flexibly combined according to actual usage needs, ensuring structural stability while taking into account the measurement accuracy and load-bearing requirements in different scenarios, resulting in accurate and reliable test results.

[0019] In summary, this invention can achieve nonlinear calibration of all force-measuring components to improve measurement accuracy, while simplifying the patch layout space, effectively reducing the overall volume, realizing a small and compact sensor design, and adapting to more confined installation conditions. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a nonlinear force sensing unit;

[0021] Figure 2 This is a schematic diagram of the first patch position of a nonlinear force sensing unit;

[0022] Figure 3 This is a schematic diagram showing the position of the second patch of a nonlinear force sensing unit.

[0023] Figure 4 This is a schematic diagram showing the position of the third patch in a nonlinear force sensing unit.

[0024] Figure 5 This is a schematic diagram showing the position of the fourth patch in a nonlinear force sensing unit;

[0025] Figure 6 This is a schematic diagram of the fifth patch position of a nonlinear force sensing unit;

[0026] Figure 7 This is a schematic diagram showing the position of the sixth patch of a nonlinear force sensing unit;

[0027] Figure 8 This is a schematic diagram of the structure of a multidimensional force sensor;

[0028] Figure 9 This is a top view of the first patch position of the multidimensional force sensor;

[0029] Figure 10 This is a bottom view of the first patch position of the multidimensional force sensor;

[0030] Figure 11 This is a bottom view of the second patch position of the multidimensional force sensor;

[0031] Figure 12 This is a top view of the third patch position of the multi-dimensional force sensor;

[0032] Figure 13 This is a bottom view of the third patch position of the multi-dimensional force sensor;

[0033] Figure 14 This is a schematic diagram of an elastic unit structure for a nonlinear force sensing unit;

[0034] Figure 15 This is a schematic diagram of the same elastic unit structure of a multidimensional force sensor;

[0035] Figure 16 This is a schematic diagram of the different elastic unit structures of a multidimensional force sensor;

[0036] Figure 17 This is a structural diagram of a split-type connector.

[0037] Figure label:

[0038] 1. Fixed frame; 11. Mounting hole; 2. Elastic unit; 21. Elastic body; 3. Connector. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] The components of the embodiments of the invention described and shown in the accompanying drawings can typically be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0041] 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.

[0042] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., 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 the invention and for 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 the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] Example 1

[0045] like Figure 1 As shown, the present invention proposes a nonlinear force sensing unit, including a fixed frame 1. The fixed frame 1 serves as a fixed reference component for the force sensing unit, enabling a stable connection between the force sensing unit and external devices and providing installation support for an elastic unit 2. An elastic unit 2 is disposed inside the fixed frame 1. The elastic unit 2 senses strain signals under external forces, providing a core deformation basis for six-dimensional force measurement. A connector 3 connects the fixed frame 1 to the elastic unit 2. The connector 3 connects the device and the detection component, causing the elastic unit 2 to deform when the detection component is subjected to axial tension and torsion. The fixed frame 1 is a closed structure (such as a ring or square), which ensures uniform force distribution and improves the overall structural stability of the force sensing unit. The elastic unit 2 includes four sets of elastic bodies 21 arranged in a ring array, forming a single-layer nonlinear stiffness ring structure. The ring array of elastic bodies 21 can comprehensively capture strain in different directions. One end of each elastic body 21 is fixedly connected to the connector 3, and the other end is fixedly connected to the fixed frame 1, ensuring effective force transmission.

[0046] Furthermore, the aforementioned force sensing unit includes multiple sets of strain gauges. These strain gauges convert the deformation of the elastic body 21 into electrical signals, enabling quantitative measurement of force and torque. The strain gauges are mounted on the upper and lower sides of the elastic unit 2. These strain gauges on both sides can comprehensively capture the bending strain of the elastic body 21, improving measurement accuracy. The fixed frame 1 has multiple sets of mounting holes 11 arranged in a circular array. These mounting holes 11 are used to insert fasteners, enabling a detachable connection between the fixed frame 1 and external equipment.

[0047] At least one set of strain gauges is mounted on the upper and / or lower sides of the elastomer 21. The strain gauges are arranged parallel to the length of the elastomer 21, at a 45° angle, or mirror-image tilted, i.e., arranged at a 135° angle along the length of the elastomer 21. The strain gauges are mounted on the elastomer 21 using glass micro-melting or adhesive curing technology. This technology enhances the bonding strength between the strain gauges and the elastomer 21, ensuring the stability and reliability of the strain gauge measurements.

[0048] Specifically, such as Figure 2 As shown, each of the four sets of elastic bodies 21 has a set of strain gauges arranged along its length at its bottom, used to measure Fz or simultaneously measure Mx and My.

[0049] like Figure 3 Each of the four sets of elastic bodies 21 has a set of strain gauges installed at the bottom, arranged at 45° / 135° with respect to the length of the elastic body 21, for measuring Mz. When the sensor size is large, the strain gauges arranged at 45° or 135° on the upper and lower sides for measuring shear force can be moved to the left and right sides, and the strain gauges on the left and right sides can be arranged at 0° or 180° to measure tension and compression, thereby improving the measurement accuracy.

[0050] like Figure 4 Each of the four sets of elastic bodies 21 has a set of strain gauges arranged along its length and a set of strain gauges arranged at 45° / 135° with the length of the elastic body 21, which are used to simultaneously measure Mx, My and Mz.

[0051] like Figure 5 Two sets of coaxially arranged elastic bodies 21 each have a set of strain gauges installed at their bottom along their length direction; the other two sets of coaxially arranged elastic bodies 21 each have a set of strain gauges installed at their bottom at 45° / 135° to the length direction of the elastic body 21, for simultaneously measuring Fz and Mz.

[0052] like Figure 6 Each of the four sets of elastic bodies 21 has two sets of strain gauges arranged along its length at its bottom, which are used to simultaneously measure Fz, Mx and My.

[0053] like Figure 7 Two sets of coaxially arranged elastic bodies 21 are each equipped with two sets of strain gauges arranged along their length at their bottom; the other two sets of coaxially arranged elastic bodies 21 are each equipped with a set of strain gauges arranged along their length at their bottom, and a set of strain gauges arranged at 45° / 135° with the length of the elastic body 21, for simultaneously measuring Fz, Mx, My and Mz.

[0054] The fixed frame 1, the elastic unit 2, and the connector 3 are integrally molded. The integral molding structure can eliminate the gap between the components, improve the structural rigidity and measurement accuracy of the sensing unit, and simplify the processing technology.

[0055] In this embodiment, the external equipment and the connector 3 are detachably connected by bolts. The fixed frame 1 stably supports the overall structure and provides a reference support for the testing operation. When external forces and torques are applied to the connector 3, the connector 3 is subjected to force and undergoes displacement and torsion, and the load is synchronously transmitted to the connected elastic unit 2.

[0056] Multiple sets of elastic bodies 21 arranged in a ring array within the elastic unit 2 undergo elastic deformation under load. Relying on the characteristics of the single-layer nonlinear stiffness ring structure, it can sense stress deformation in different directions from all directions. Strain gauges attached to the upper and lower sides of the elastic body 21 capture the deformation state of the elastic body 21 in real time. With the help of glass micro-solidification to stabilize the attached structure, the mechanical deformation signal is converted into the corresponding electrical signal.

[0057] Subsequent acquisition and processing of electrical signals allow for the calculation of force and torque values. The integrally molded fixed frame 1, elastic unit 2, and connecting parts 3 have no assembly gaps, ensuring stable and smooth load transmission. At the same time, all deformable components can be nonlinearly calibrated, effectively eliminating measurement nonlinearity errors and improving overall detection accuracy.

[0058] Example 2

[0059] like Figure 8 As shown, the present invention proposes a multidimensional force sensor comprising two sets of nonlinear force sensing units according to Embodiment 1. The two sets of nonlinear force sensing units are connected by a connector 3, which is cylindrical. Each set of nonlinear force sensing units is connected to either a fixed end or a force-bearing end. Specifically, a fixed frame 1 is fixedly mounted on a base, and a connecting device and a detection component are mounted on the connector 3; or a connecting device and a detection component are mounted on the fixed frame 1, and the connector 3 is fixedly mounted on the base. Mounting holes 11 are provided on the fixed frame 1 of the two sets of nonlinear force sensing units for inserting fasteners, enabling a detachable connection between the fixed frame 1 and external devices.

[0060] In this embodiment, the elastic unit 2 in each of the two sets of nonlinear force sensing units includes four sets of elastic bodies 21, which are arranged in a ring array. The ring array of elastic bodies 21 can comprehensively capture strain in different directions. One end of the elastic body 21 is fixedly connected to the connector 3, and the other end of the elastic body 21 is fixedly connected to the fixed frame 1 to ensure effective force transmission.

[0061] In this embodiment, a ring array design of four sets of elastic bodies 21 is adopted, which can improve the accuracy and resolution of six-dimensional force measurement while maintaining a compact overall structure. The distribution of the four sets of elastic bodies 21 can better disperse stress, avoid local stress concentration, extend the service life of the sensor, and adapt to higher precision measurement scenarios.

[0062] Furthermore, two sets of nonlinear force sensing units work together to achieve precise perception of force and torque in six dimensions.

[0063] It is worth mentioning that the connector 3 has a cylindrical structure, which facilitates machining. The cylindrical structure of the connector 3 ensures uniform force transmission in all directions and avoids stress concentration. Furthermore, since no strain gauges need to be installed on the connector 3, its length can be designed to be extremely short, thereby reducing the distance between the two sets of fixing frames 1 and making the overall structure more compact. The fixing frame 1, the elastic unit 2, and the connector 3 are integrally molded. This integral molding structure eliminates gaps between components, improves the structural rigidity and measurement accuracy of the sensor, and simplifies the manufacturing process.

[0064] Specifically, the force sensor also includes multiple strain gauges. These strain gauges convert the deformation of the elastic body 21 into electrical signals, enabling quantitative measurement of force and torque. The strain gauges are mounted on the upper and lower sides of the elastic body 21, allowing for comprehensive capture of the bending strain of the elastic body 21 and improving measurement accuracy. The strain gauges are arranged parallel to the length of the elastic body 21, at a 45° angle, or mirror-mounted at a 135° angle. The strain gauges are mounted on the elastic body 21 using glass micro-melting or adhesive curing techniques. These techniques enhance the bonding strength between the strain gauge and the elastic body 21, ensuring the stability and reliability of the strain gauge measurements.

[0065] Specifically, such as Figure 9 and Figure 10 Each of the four sets of elastic bodies 21 at the top and the four sets of elastic bodies 21 at the bottom is equipped with a set of strain gauges arranged along its length, which are used to simultaneously measure Fx, Fy, Mx and My.

[0066] like Figure 9 and Figure 11 Each of the four sets of elastic bodies 21 at the top has a strain gauge mounted on its top, arranged along its length. Of the four sets of elastic bodies 21 at the bottom, two sets of coaxially arranged elastic bodies 21 each have a strain gauge mounted on their bottom, arranged along their length; the other two sets of coaxially arranged elastic bodies 21 each have a strain gauge mounted on their bottom at 45° / 135° to the length of the elastic body 21, used to simultaneously measure Fz, Mx, My, and Mz.

[0067] like Figure 12 and Figure 13 Each of the four sets of elastic bodies 21 at the top has two sets of strain gauges arranged along its length. Each of the four sets of elastic bodies 21 at the bottom has one set of strain gauges arranged along its length and one set of strain gauges arranged at 45° / 135° to the length of the elastic body 21, for simultaneously measuring Fx, Fy, Fz, Mx, My and Mz.

[0068] In this embodiment, the elastic element 2 of the first layer measured:

[0069] ; .

[0070] The measurements were taken from the elastic element 2 of the second layer:

[0071] ; .

[0072] Where h is the distance from the point of force application to the neutral surface of the first layer of elastic element 2; L is the distance between the neutral surfaces of the two layers of elastic element 2.

[0073] The solution yields:

[0074] ; ;

[0075] ; .

[0076] In this embodiment, a stable mounting reference is formed by the cooperation of two sets of nonlinear force sensing units. Fasteners are inserted into the mounting holes 11 to achieve a firm connection between the sensor and the external device. The mounting holes 11 distributed in a ring array ensure uniform force during installation and avoid stress deformation that could affect measurement accuracy.

[0077] When external forces and torques are applied to the sensor, they are transmitted through the connector 3. The cylindrical connector 3 ensures uniform force transmission in all directions, avoiding stress concentration. Since the fixed frame 1, elastic unit 2, and connector 3 are integrally formed, gaps between components can be eliminated, ensuring that forces and torques are transmitted to the elastic unit 2 without loss.

[0078] The four sets of elastic bodies 21 of elastic unit 2 are arranged in a ring array. The two sets of elastic units 2 work together to fully capture the strain signal under the action of external force. The elastic body 21 undergoes a small deformation under the action of force and torque, and the strain gauges installed on its upper and lower sides convert the deformation into an electrical signal.

[0079] Four sets of elastic bodies 21 can respectively sense three force components Fx, Fy, Fz and three torque components Mx, My, Mz in three-dimensional space. Through the acquisition and analysis of the corresponding electrical signals, accurate quantitative measurement of six-dimensional force is achieved. At the same time, the compact layout design of the two sets of nonlinear force sensing units replaces the traditional four-sided patch structure of the connector 3, which greatly reduces the overall size of the sensor and achieves a balance between structural compactness and measurement accuracy.

[0080] Example 3

[0081] like Figure 14As shown, the difference between this embodiment and Embodiment 1 is that the elastic unit 2 includes three sets of elastic bodies 21. The four sets of elastic bodies 21 are arranged in a ring array, and the three sets of elastic bodies 21 arranged in the ring array capture strain in different directions.

[0082] It is worth mentioning that each set of strain gauges can be attached to two layers of the elastomer 21 respectively to form a full bridge and improve sensitivity.

[0083] Example 4

[0084] like Figure 15 As shown, the difference between this embodiment and Embodiment 2 is that the elastic unit 2 in the two sets of nonlinear force sensing units in this multidimensional force sensor includes three sets of elastic bodies 21. The three sets of elastic bodies 21 are arranged in a ring array. The ring array of elastic bodies 21 can capture strain in different directions, taking into account both measurement accuracy and structural compactness.

[0085] It is worth mentioning that each set of strain gauges can be attached to two layers of the elastomer 21 respectively to form a full bridge and improve sensitivity.

[0086] Example 5

[0087] like Figure 16 As shown, the difference between this embodiment and Embodiment 2 is that the elastic unit 2 in the two sets of nonlinear force sensing units in this multidimensional force sensor includes three sets of elastic bodies 21 in one set of elastic units 2 and four sets of elastic bodies 21 in the other set of elastic units 2. The elastic bodies 21 in both sets of elastic units 2 are arranged in a ring array. The ring array distribution of elastic bodies 21 can comprehensively capture strain in different directions, taking into account both measurement accuracy and structural compactness.

[0088] Example 6

[0089] like Figure 17 As shown, the difference between this embodiment and Embodiment 2 is that the connector 3 in this embodiment is a split type, with both ends of the connector 3 separated from the middle position. The two ends are respectively fixed in two sets of nonlinear force sensing units, and the two ends of the connector 3 are fixedly connected to the middle position by bolts. The split design reduces processing costs, and the bolt connection method also facilitates combination and use.

[0090] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A nonlinear force sensing unit, characterized in that, include: A fixed frame (1) is provided with an elastic unit (2) inside the fixed frame (1). The fixed frame (1) is connected to a connector (3) through the elastic unit (2). The fixed frame (1) and the connector (3) are respectively connected to the fixed end or the force-bearing end. Multiple strain gauges are installed on the side of the elastic unit (2). The elastic unit (2) includes at least three sets of elastic bodies (21). The multiple sets of elastic bodies (21) are arranged in a ring array to form a single-layer nonlinear stiffness ring structure.

2. The nonlinear force sensing unit according to claim 1, characterized in that, One end of the elastic body (21) is fixedly connected to the connector (3), and the other end of the elastic body (21) is fixedly connected to the fixed frame (1).

3. The nonlinear force sensing unit according to claim 2, characterized in that, The fixed frame (1) has multiple sets of mounting holes (11).

4. The nonlinear force sensing unit according to claim 3, characterized in that, At least one set of strain gauges is installed on the upper and / or lower sides of the elastic body (21), and the strain gauges are arranged parallel to or at 45° / 135° along the length of the elastic body (21).

5. The multidimensional force sensor according to claim 5, characterized in that, The fixed frame (1), elastic unit (2) and connector (3) are integrally formed.

6. A multidimensional force sensor, comprising two sets of nonlinear force sensing units as described in any one of claims 1-5, characterized in that, The two sets of nonlinear force sensing units are connected by a connector (3), which is columnar, and the two sets of nonlinear force sensing units are respectively connected to the fixed end or the force-bearing end.

7. The multidimensional force sensor according to claim 6, characterized in that, The number of elastic bodies (21) in the two sets of nonlinear force sensing units is set independently, and the two numbers may be the same or different, forming a double-layer nonlinear stiffness ring structure.

8. The multidimensional force sensor according to claim 6, characterized in that, At least one set of strain gauges is installed on the upper and / or lower sides of the elastic body (21) in the two sets of nonlinear force sensing units, and the strain gauges are arranged parallel to the length direction of the elastic body (21) or arranged at 45° / 135°.

9. The multidimensional force sensor according to claim 8, characterized in that, The strain gauge is installed on the elastomer (21) using glass micro-solution or glue curing technology.

10. The multidimensional force sensor according to claim 6, characterized in that, The two sets of nonlinear force sensing units and their intermediate connecting parts (3) are integrally formed or fixedly connected.

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