A high-load, small-deformation force measuring device and its decoupling method

Abstract

This invention discloses a high-load, small-deformation force measuring device and decoupling method, belonging to the technical field of mechanical measurement devices. It includes: a balance body, which is a flat, elongated structure; flat inner cavities symmetrically machined on both sides of the balance body, with two symmetrical tension / compression elements longitudinally arranged in each cavity, and two sets of orthogonal double-cross decoupling hinges symmetrically arranged at the upper and lower ends of each tension / compression element; a discontinuity groove, inclinedly arranged in the middle of the balance body, dividing the balance body into a front and rear section; and two bending / torsion elements, respectively arranged laterally in the flat inner cavities. The front and rear ends of the balance body are connected only through the tension / compression and bending / torsion elements, with grid-like decoupling springs between the bending / torsion elements and the balance body. This invention fully utilizes the flat inner cavity space of the model, designing the balance as a flat structure, thereby improving the overall deformation resistance of the balance while meeting the sensitivity requirements of each component.

Description

Technical Field

[0001] This invention belongs to the field of mechanical measurement device technology, and more specifically, this invention relates to a high-load, small-deformation force measuring device and a decoupling method. Background Technology

[0002] During aircraft development, extensive wind tunnel simulations are typically conducted to obtain the aerodynamic characteristics of a specific aerodynamic configuration. This usually involves measuring the magnitude, direction, and point of application of aerodynamic loads (forces and moments) acting on the model. The core force measuring device is a specially customized high-precision multi-component force (including moment) sensor. In aerodynamic testing, a cylindrical rod strain gauge balance is commonly used to measure six components acting on the model: lift Y, pitch moment Mz, axial force X, roll moment Mx, lateral force Z, and yaw moment My. The force measurement principle of this strain gauge balance mainly includes the processes of "force / moment vector action → deformation of the balance structure elastic body → Wheatstone bridge signal → orthogonally decoupled load components." This process decouples the three-dimensional aerodynamic vectors acting on the model or prototype into load scalars, and uses a pre-calibrated calculation matrix to convert the bridge signal into forces and moments about the orthogonal x, y, and z axes in a Cartesian coordinate system.

[0003] In wind tunnel force measurement tests of large-wingspan, flat-structure aerodynamic aircraft, the large wing span and flat fuselage result in significant load mismatches between the high longitudinal (y-axis) load and the low axial (x-axis) and lateral (z-axis) loads. Furthermore, the flat fuselage leads to a further reduction in the internal space of the model, causing insufficient load-bearing capacity for traditional cylindrical force measuring devices. This results in large deformation under combined loads, easily causing model vibration and threatening test safety. Matching the load ranges of each component is difficult, hindering the aerodynamic measurement requirements across a wide attitude angle range. The force measuring device to be developed exhibits high load capacity and a large lift-to-drag ratio, making the structural design of the measuring elements and the sensitivity matching of each measuring component extremely challenging. This is mainly reflected in:

[0004] The limited space within the model's internal cavity presents challenges for structural design. Traditional cylindrical force measuring devices primarily utilize the bending deformation of cantilever beams to measure the Y, Mz, X, Z, and My components, and typically employ torsional shear to measure the Mx component. While these methods offer advantages such as simple structure and mature decoupling techniques, they are ill-suited to the force measurement requirements of flat internal cavities. Directly adopting a flat structural design without altering the measurement method leads to a significant decrease in the bending resistance of the component section under high longitudinal loads, resulting in a marked increase in deformation. Furthermore, the conflict between sensitivity and structural stiffness becomes acute under low lateral loads, making it difficult to fully utilize the lateral space and enhance lateral stiffness while achieving adequate sensitivity.

[0005] Sensitivity matching difficulties arise from multi-component load mismatch. Due to the multi-component coupling of the force measuring device, changes in a certain key dimension will cause changes in the sensitivity of multiple measurement components. In order to ensure the sensitivity of each component, the overall structural dimensions, sensitive element design, and patch placement must be coordinated to ensure that the deformation of each patch position is within a reasonable range, so as to ensure that the output of each component signal has sufficient resolution.

[0006] Setting up high-load-bearing tensile and compressive small deformation measuring elements is difficult. The force balance measurement principle based on tensile and compressive deformation for high load-bearing applications requires the assembly of pre-fabricated tensile and compressive elements. The assembly structure design is complex, and the machining and assembly precision is extremely high. In addition, machining and assembly errors and assembly stress can seriously affect the measurement accuracy and reliability, making it difficult to meet the accuracy requirements of experimental measurements.

[0007] Therefore, in order to meet the high load and high precision aerodynamic force measurement requirements of special aerodynamic layouts, and considering the characteristics of the model's internal cavity space and load-bearing capacity requirements, a structural scheme and decoupling method for the force measuring device under mixed modes of tension-compression deformation, bending deformation and torsional deformation in a flat structure under overall processing conditions are proposed to meet the force measurement test requirements of this type of layout test model. Summary of the Invention

[0008] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.

[0009] To achieve these and other advantages according to the invention, the present invention provides a high-load, low-deformation force measuring device, comprising:

[0010] The balance body is a flat, elongated structure;

[0011] The balance body has symmetrically machined flat inner cavities on both sides. Each flat inner cavity has two symmetrical tension and compression elements arranged longitudinally. Each tension and compression element has two sets of orthogonal double cross decoupling hinges symmetrically arranged at its upper and lower ends.

[0012] A disconnecting groove is inclinedly disposed in the middle of the balance body, and the disconnecting groove divides the balance body into two parts: a front end and a rear end.

[0013] Two bending and twisting elements are respectively arranged laterally in the flat inner cavity. The front and rear ends of the balance body are connected only through the tension and compression elements and the bending and twisting elements. A grid-shaped decoupling spring is provided between the bending and twisting elements and the balance body.

[0014] Preferably, in the flat inner cavity, two tension / compression elements are symmetrically arranged on both sides of the bending / twisting element, and the horizontal distance between each tension / compression element and the bending / twisting element is equal.

[0015] In the two sets of orthogonal double cross decoupling hinges at one end of the tension / compression element, the horizontal sides of the double cross decoupling hinge connected to the tension / compression element are machined with arc-shaped grooves, and the longitudinal sides of the double cross decoupling hinge connected to the balance body are machined with arc-shaped grooves. The arc-shaped grooves of the two sets of double cross decoupling hinges are orthogonal and perpendicular.

[0016] Preferably, the tension / compression element has an "I"-shaped column structure. Of the four tension / compression elements in the two flat inner cavities, the two tension / compression elements on the front side of the balance body are designated as tension / compression element A and tension / compression element B, respectively, and the two tension / compression elements on the rear side of the balance body are designated as tension / compression element C and tension / compression element D, respectively. Two strain gauges arranged in a "T" shape perpendicular to each other are attached to the front side of tension / compression element A, numbered S1 and S2. Two strain gauges arranged in a "T" shape perpendicular to each other are attached to the rear side of tension / compression element A, numbered S3 and S4. The four strain gauges numbered S1, S2, S3, and S4 form an H1 bridge.

[0017] The strain gauge mounting positions, specifications, and bridging methods on tension / compression elements B, C, and D are the same as those on tension / compression element A.

[0018] The strain gauges numbered S5, S6, S7, and S8 are sequentially attached to the tension / compression element B. The four strain gauges numbered S5, S6, S7, and S8 form an H2 bridge.

[0019] The strain gauges numbered S9, S10, S11, and S12 are sequentially attached to the tension / compression element C. The four strain gauges numbered S9, S10, S11, and S12 form an H3 bridge.

[0020] The tension / compression element D has strain gauges numbered S13, S14, S15, and S16 attached to it in sequence. The four strain gauges numbered S13, S14, S15, and S16 form an H4 bridge.

[0021] Preferably, the bending and torsion element has a horizontal "door" shaped structure. The two bending and torsion elements are respectively designated as bending and torsion element A and bending and torsion element B. The y-direction elastic beam of bending and torsion element A is attached with strain gauges numbered S17, S18, S19, and S20. The y-direction elastic beam of bending and torsion element B is attached with strain gauges numbered S21, S22, S23, and S24. The eight strain gauges numbered S17, S18, S19, S20, S21, S22, S23, and S24 form an M3 bridge for directly measuring the axial force X.

[0022] Preferably, strain gauges numbered S25 and S26 are attached to the outer side of the elastic beam in the z-direction of the bending-torsion element A, and strain gauges numbered S27 and S28 are attached to the outer side of the elastic beam in the z-direction of the bending-torsion element B. The four strain gauges numbered S25, S26, S27, and S28 form a bending deformation measuring bridge M5 for measuring the lateral force Z.

[0023] Preferably, strain gauges numbered S29, S30, S31, and S32 are attached to the inner side of the elastic beam in the z-direction of the bending-torsion element A, and strain gauges numbered S33, S34, S35, and S36 are attached to the inner side of the elastic beam in the z-direction of the bending-torsion element B. The eight strain gauges numbered S29, S30, S31, S32, S33, S34, S35, and S36 form a torsional deformation measuring bridge M6 for measuring the yaw moment My.

[0024] Preferably, the front end of the balance body is provided with a model interface, the model interface is provided with a positioning pin, a threaded hole and a central wiring hole, and the central wiring hole is located on the central axis of the balance body.

[0025] The balance body is provided with tension and compression wiring holes and bending and twisting wiring holes that are connected to the central wiring hole;

[0026] The rear end of the balance body is provided with a support rod interface, and the support rod interface is provided with a positioning keyway and a locking wedge.

[0027] Preferably, the upper surface of the balance body is provided with a reference platform, and the reference platform is provided with a lifting hole.

[0028] Preferably, the balance body has a patch groove for attaching strain gauges to the bending and torsional elements and the tension and compression elements.

[0029] A decoupling method for a high-load, small-deformation force measuring device includes:

[0030] First, the components of lift Y, pitch moment Mz and roll moment Mx are decoupled. The output of bridge H1 is expressed as: H1=(-S1+S2-S3+S4) / 4;

[0031] The output of the H2 bridge is expressed as: H2 = (-S5 + S6 - S7 + S8) / 4;

[0032] The output of the H3 bridge is expressed as: H3 = (-S9 + S10 - S11 + S12) / 4;

[0033] The output of the H4 bridge is expressed as: H4 = (-S13 + S14 - S15 + S16) / 4;

[0034] The lift Y, pitch moment Mz, and roll moment Mx are a 4-bridge combination, with decoupling measures M1, M2, and M4. The calculation method is as follows:

[0035] Lift force Y: M1 = (H1 + H2 + H3 + H4) / 4;

[0036] Pitch moment Mz: M2=(-H1-H2+H3+H4) / 4;

[0037] Rolling torque Mx: M4 = (-H1 + H2 - H3 + H4) / 4;

[0038] Then, since the decoupling design has been completed in the structure, the three components of axial force X, lateral force Z, and yaw moment My are directly measured by bridges M3, M5, and M6 respectively; among them, uniaxial strain gauges are used for S17~S28, and half-bridge strain gauges are used for S29~S36; the bridge groups and signal outputs of each strain gauge are shown below:

[0039] Axial force X: M3 = (S17 - S18 - S19 + S20 + S21 - S22 - S23 + S24) / 8;

[0040] Lateral force Z: M5 = (-S25 + S26 + S27 - S28) / 4;

[0041] Yaw moment My: M6 = (S29 - S30 - S31 + S32 + S33 - S34 - S35 + S36) / 8;

[0042] A three-dimensional model of the high-load, small-deformation measurement device was established, including strain gauges numbered at each patch. The model was imported into finite element simulation software, and loads and boundary conditions for each load step were set according to the load conditions. The mesh was generated and the solution was obtained. During post-processing, the average strain of each strain gauge for each load step was extracted using a batch processing script.

[0043] The present invention has at least the following beneficial effects:

[0044] First, by fully utilizing the flat internal space of the model and designing the balance as a flat structure, the overall deformation resistance of the balance is improved while meeting the sensitivity requirements of each component. Second, a decoupled hinge and tension / compression element structure is set up, and aerodynamic measurement methods for lift Y, pitch moment Mz, and roll moment Mx are realized through electrical decoupling, further reducing the amount of balance deformation and improving the overall stiffness of the balance. Third, a balance measurement structure based on the tension / compression deformation principle is realized under non-assembly conditions, eliminating the processing and assembly errors of tension / compression elements, reducing the manufacturing difficulty of the balance, and improving the calibration accuracy of the balance. Fourth, by combining mechanical structure and bridge decoupling, the crosstalk of lift to axial force X and roll moment Mx under high lift-to-drag ratio and low lift-to-roll ratio load conditions is reduced, improving the measurement accuracy of other components under high load conditions.

[0045] The balance adopts a flat, internal structure with integral machining, meaning that each measuring element is directly manufactured using conventional machining methods, eliminating the need for assembly of tension and compression elements into the final force measuring device. Through rational structural design, bridge layout, and decoupling design, the system aims to improve load-bearing capacity, reduce deformation, and match the sensitivity of each component. Four tension / compression elements with decoupling hinges and two bending / torsion elements are symmetrically arranged to measure all aerodynamic forces. All strain gauges are positioned for easy attachment and pressure application, ultimately forming seven bridges. Decoupling calculations using the bridge signals yield six force components: lift (Y), pitch moment (Mz), axial force (X), roll moment (Mx), lateral force (Z), and yaw moment (My). Mechanical interfaces for adapting the model and support rods are provided for convenient wiring, positioning, and disassembly / reassembly. Therefore, this technical solution achieves a high-load, low-deformation force measuring device composed of integrally machined elements measuring mixed tension, compression, bending, and torsional deformations, along with a decoupling method.

[0046] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description

[0047] Figure 1 This is a general structural diagram of a high-load, small-deformation force measuring device;

[0048] Figure 2 This is a side view of the force measuring device with high load and small deformation.

[0049] Figure 3 This is a top view of a high-load, small-deformation force measuring device;

[0050] Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure at point AA;

[0051] Figure 5 for Figure 2 Schematic diagram of the cross-sectional structure at point BB;

[0052] Figure 6 A schematic diagram showing the composition of each bridge circuit and the configuration of the strain gauges;

[0053] Figure 7 This is a deformation simulation cloud diagram of the high-load, small-deformation force measuring device of the present invention;

[0054] Figure 8 This is a simulated cloud map of a modified traditional balance.

[0055] The corresponding labels for each structure are as follows: Balance body 100, reference platform 101, lifting hole 102, flat inner cavity 103, double cross decoupling hinge 104, tension / compression element A 105, tension / compression element B 106, tension / compression element C 107, tension / compression element D 108, disconnect groove 109, decoupling spring 111, bending / torsion element A 112, bending / torsion element B 113, model interface 114, positioning pin 115, threaded hole 116, center wiring hole 117, tension / compression wiring hole 118, bending / torsion wiring hole 119, support rod interface 120, positioning keyway 121, locking wedge 122, patch groove 123. Detailed Implementation

[0056] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0057] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0058] like Figures 1-6 As shown, a high-load, small-deformation force measuring device includes:

[0059] The balance body 100 has a flat and elongated structure. A reference platform 101 is provided on the upper surface of the balance body, and a lifting hole 102 is provided on the reference platform 101. The reference platform 100 is a processing and testing reference and a measurement reference for the attitude angle of the balance body 100 during installation. It is used to obtain the actual attitude angle of the balance body 100 after installation. The lifting hole is used to facilitate the lifting and disassembly of the balance body 100.

[0060] The balance body 100 has symmetrically machined flat inner cavities 103 on both sides. Each flat inner cavity 103 contains two symmetrical tension / compression elements arranged longitudinally. Each tension / compression element has two sets of orthogonal double-cross decoupling hinges 104 symmetrically arranged at its upper and lower ends. The double-cross decoupling hinges 104 are integral with the tension / compression elements. This structural arrangement allows the tension / compression elements to primarily bear tension and compression, while isolating and decoupling forces and moments in other directions. In other words, the double-cross decoupling hinges 104 isolate bending moments. Figure 1 As shown, for the two sets of orthogonal double cross decoupling hinges 104 at one end of the tension and compression element, the double cross decoupling hinge connected to the tension and compression element has arc-shaped grooves on both sides of its transverse direction (along the axis of the balance body), and the double cross decoupling hinge connected to the balance body 100 has arc-shaped grooves on both sides of its longitudinal direction. The arc-shaped grooves of the two sets of double cross decoupling hinges are orthogonal and perpendicular.

[0061] Of the four tension / compression elements in the two flat inner cavities 103, the two tension / compression elements on the front side of the balance body are designated as tension / compression element A105 and tension / compression element B106, respectively, and the two tension / compression elements on the rear side of the balance body 100 are designated as tension / compression element C107 and tension / compression element D108, respectively. Two strain gauges arranged in a "T" shape perpendicular to each other are attached to the front side of tension / compression element A105, and are numbered S1 and S2, respectively. Two strain gauges arranged in a "T" shape perpendicular to each other are attached to the rear side of tension / compression element A105, and are numbered S3 and S4, respectively. The four strain gauges numbered S1, S2, S3, and S4 form an H1 bridge.

[0062] The strain gauge mounting positions, specifications, and bridging methods on tension / compression elements B106, C107, and D108 are the same as those on tension / compression element A105.

[0063] The tension / compression element B106 has strain gauges numbered S5, S6, S7, and S8 attached to it in sequence. The four strain gauges numbered S5, S6, S7, and S8 form an H2 bridge.

[0064] The strain gauges numbered S9, S10, S11, and S12 are sequentially attached to the tension / compression element C107. The four strain gauges numbered S9, S10, S11, and S12 form an H3 bridge.

[0065] The tension / compression element D108 has strain gauges numbered S13, S14, S15, and S16 attached to it in sequence. The four strain gauges numbered S13, S14, S15, and S16 form an H4 bridge.

[0066] A disconnecting groove 109 is obliquely formed in the middle of the balance body 100. The disconnecting groove 109 divides the balance body 100 into two parts: a front end and a rear end. The disconnecting groove 109 extends through the balance body 100 from behind the bending and twisting element A. The disconnecting groove 109 is a spatial separation structure, which is processed by electrical discharge machining. A certain gap is maintained between the front end and the rear end of the balance body 100 to ensure that the front and rear parts of the balance body 100 will not contact each other after deformation.

[0067] Two bending and twisting elements are respectively arranged laterally in the flat inner cavity 103. The front and rear ends of the balance body 100 are connected only through tension and compression elements and bending and twisting elements. A grid-shaped decoupling spring 111 is provided between the bending and twisting elements and the balance body. The grid-shaped decoupling spring 111 has a certain elasticity and is used to reduce crosstalk of large longitudinal loads to the bending and twisting elements. In the flat inner cavity 103, two tension and compression elements are symmetrically arranged on both sides of the bending and twisting elements, and the horizontal distance between each tension and compression element and the bending and twisting element is equal.

[0068] The bending and torsion elements have a horizontal "door" shaped structure. The two bending and torsion elements are designated as bending and torsion element A112 and bending and torsion element B113, respectively. The y-direction elastic beam of bending and torsion element A112 (the vertical direction perpendicular to the axial and transverse directions of the balance body) is attached with strain gauges numbered S17, S18, S19, and S20. The y-direction elastic beam of bending and torsion element B113 is attached with strain gauges numbered S21, S22, S23, and S24. The eight strain gauges numbered S17, S18, S19, S20, S21, S22, S23, and S24 form an M3 bridge for directly measuring the axial force X.

[0069] Strain gauges numbered S25 and S26 are attached to the outer side of the z-direction elastic beam (along the transverse direction of the balance body) of the bending-torsion element A112, and strain gauges numbered S27 and S28 are attached to the outer side of the z-direction elastic beam of the bending-torsion element B113. The four strain gauges numbered S25, S26, S27, and S28 form a bending deformation measuring bridge M5 used to measure the lateral force Z.

[0070] The strain gauges numbered S29, S30, S31, and S32 are attached to the inner side of the elastic beam in the z-direction of the bending-torsion element A112, and the strain gauges numbered S33, S34, S35, and S36 are attached to the inner side of the elastic beam in the z-direction of the bending-torsion element B113. The eight strain gauges numbered S29, S30, S31, S32, S33, S34, S35, and S36 form a torsional deformation measuring bridge M6 for measuring the yaw moment My.

[0071] The strain gauges that make up H1, H2, H3, H4, M3, M5, and M6 are symmetrically arranged on the bending-torsion element A, bending-torsion element B, tension-compression element A, tension-compression element B, tension-compression element C, and tension-compression element D in the flat inner cavity 103 on both sides.

[0072] The front end of the balance body 100 is provided with a model interface 114. The model interface 114 is provided with a positioning pin 115, a threaded hole 116, and a central wiring hole 117. The central wiring hole 117 is located on the central axis of the balance body 100. The model interface 114 is used to connect the model, and the positioning pin 115 and the threaded hole 116 ensure accurate model positioning and reliable connection. The central wiring hole 117 is a through hole, which allows the sensor circuitry on the model and the circuitry on the balance body 100 to be led out.

[0073] The balance body 100 is provided with a tension and compression wiring hole 118 and a bending and twisting wiring hole 119 that are connected to the central wiring hole 117. The power supply cable and the signal cable enter the straight hole of the balance axis from the front and rear tension and compression wiring holes 118 and bending and twisting wiring holes 119 respectively, and then are led out through the central wiring hole 117 of the balance.

[0074] The rear end of the balance body 100 is provided with a support rod interface 120, which is provided with a positioning keyway 121 and a locking wedge 122. The support rod interface 120 is used to connect and install the support rod, and the positioning keyway 121 and the locking wedge 122 ensure accurate positioning and reliable connection of the support rod.

[0075] The balance body 100 is provided with a patch groove 123 for attaching strain gauges to bending and torsional elements and tension and compression elements. The patch groove 123 is located on the upper and lower sides of the horizontal patching position of the bending and torsional element, exposing the patching part of the strain gauge, which facilitates the pasting and pressurization operation.

[0076] Figure 6 The diagram shown is not of the installation location of the strain gauges, but rather a schematic diagram of the strain gauge composition in each bridge circuit. Specifically, S1-S16 use Poisson effect strain gauges, S17-S28 use uniaxial strain gauges, and S29-S36 use half-bridge strain gauges.

[0077] A decoupling method for a high-load, small-deformation measuring device includes:

[0078] First, the components of lift Y, pitch moment Mz and roll moment Mx are decoupled. The output of bridge H1 is expressed as: H1=(-S1+S2-S3+S4) / 4;

[0079] The output of the H2 bridge is expressed as: H2 = (-S5 + S6 - S7 + S8) / 4;

[0080] The output of the H3 bridge is expressed as: H3 = (-S9 + S10 - S11 + S12) / 4;

[0081] The output of the H4 bridge is expressed as: H4 = (-S13 + S14 - S15 + S16) / 4;

[0082] The lift Y, pitch moment Mz, and roll moment Mx are a 4-bridge combination, with decoupling measures M1, M2, and M4. The calculation method is as follows:

[0083] Lift force Y: M1 = (H1 + H2 + H3 + H4) / 4;

[0084] Pitch moment Mz: M2=(-H1-H2+H3+H4) / 4;

[0085] Rolling torque Mx: M4 = (-H1 + H2 - H3 + H4) / 4;

[0086] Then, since the decoupling design has been completed in the structure, the three components of axial force X, lateral force Z, and yaw moment My are directly measured by bridges M3, M5, and M6 respectively; among them, uniaxial strain gauges are used for S17~S28, and half-bridge strain gauges are used for S29~S36; the bridge groups and signal outputs of each strain gauge are shown below:

[0087] Axial force X: M3 = (S17 - S18 - S19 + S20 + S21 - S22 - S23 + S24) / 8;

[0088] Lateral force Z: M5 = (-S25 + S26 + S27 - S28) / 4;

[0089] Yaw moment My: M6 = (S29 - S30 - S31 + S32 + S33 - S34 - S35 + S36) / 8;

[0090] A three-dimensional model of the high-load, small-deformation measurement device was established, including strain gauges numbered at each patch. The model was imported into finite element simulation software, and loads and boundary conditions for each load step were set according to the load conditions. The mesh was generated and the solution was obtained. During post-processing, the average strain of each strain gauge for each load step was extracted using a batch processing script. The results are shown in Table 1.

[0091] Table 1. Finite element simulation results of average strain at patches S1~S36 (unit: ×10) -6 )

[0092]

[0093]

[0094]

[0095] Based on the aforementioned bridge combination method and decoupling algorithm, the average strain of each component and the crosstalk between components are estimated, as shown in Table 2. If the relevant indicators do not meet the design requirements, the structural dimensions are adjusted, and the simulation process is repeated until the indicators meet the design requirements.

[0096] Table 2 Estimated results of average strain for each component

[0097]

[0098] Based on the strain gauge sensitivity coefficient, the sensitivity of each component and the crosstalk output sensitivity between components are estimated, as shown in Table 3.

[0099] Table 3. Calculation results of sensitivity of each component

[0100]

[0101] Figure 8 The deformation simulation cloud map is for a similar conventional balance (which does not have a disconnect groove, and the tension and compression elements and bending and torsion elements do not have a decoupling structure). The maximum deformation is 1.51mm. Figure 7The image shows a deformation simulation cloud diagram of the high-load, low-deformation force measuring device proposed in this invention. The maximum deformation is 0.94 mm. It can be seen that under the same load and boundary conditions, the high-load, low-deformation force measuring device of this invention reduces the overall deformation by 37.7%. Figure 7 , Figure 8 The shades of color in the diagram indicate the magnitude of the balance's deformation. The loads applied to both the conventional balance and the high-load, small-deformation force measuring device of this invention are identical: lift Y = 15000 N, pitch moment Mz = 800 N·m, axial force X = 1000 N, roll moment Mx = 500 N·m, lateral force Z = 2000 N, and yaw moment My = 200 N·m.

[0102] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.

[0103] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A high load small deformation force measuring device, characterized by, The application relates to a balance body, which is a flat long strip structure. Two flat inner cavities are symmetrically processed on two sides of the balance body, two symmetric tension and pressure elements are longitudinally arranged in each flat inner cavity, and two groups of orthogonal double-cross decoupling hinges are symmetrically arranged at the upper and lower ends of each tension and pressure element. A disconnection groove is obliquely arranged in the middle of the balance body, and the disconnection groove divides the balance body into a front end and a rear end. Two bending and torsion elements are transversely arranged in the flat inner cavities, the front end and the rear end of the balance body are only connected through the tension and pressure elements and the bending and torsion elements, and a grid-shaped decoupling elastic sheet is arranged between the bending and torsion elements and the balance body. The tension and pressure element is an I-shaped vertical column structure, two tension and pressure elements on one side of the front end of the balance body are respectively marked as tension and pressure element A and tension and pressure element B, and two tension and pressure elements on one side of the rear end of the balance body are respectively marked as tension and pressure element C and tension and pressure element D; two strain gauges in a T-shaped arrangement and perpendicular to each other are pasted on the front side of the tension and pressure element A, and are numbered as S1 and S2; two strain gauges in a T-shaped arrangement and perpendicular to each other are pasted on the rear side of the tension and pressure element A, and are numbered as S3 and S4; four strain gauges numbered as S1, S2, S3 and S4 form an H1 electric bridge. The pasting positions, specifications and bridge forming modes of the strain gauges on the tension and pressure element B, the tension and pressure element C and the tension and pressure element D are the same as those of the tension and pressure element A. The tension and pressure element B is sequentially pasted with strain gauges numbered as S5, S6, S7 and S8, and four strain gauges numbered as S5, S6, S7 and S8 form an H2 electric bridge. The tension and pressure element C is sequentially pasted with strain gauges numbered as S9, S10, S11 and S12, and four strain gauges numbered as S9, S10, S11 and S12 form an H3 electric bridge. The tension and pressure element D is sequentially pasted with strain gauges numbered as S13, S14, S15 and S16, and four strain gauges numbered as S13, S14, S15 and S16 form an H4 electric bridge. The bending and torsion element is in a horizontal door-shaped structure, and two bending and torsion elements are respectively marked as bending and torsion element A and bending and torsion element B; strain gauges numbered as S17, S18, S19 and S20 are pasted on the y-direction elastic beam of the bending and torsion element A, and strain gauges numbered as S21, S22, S23 and S24 are pasted on the y-direction elastic beam of the bending and torsion element B; eight strain gauges numbered as S17, S18, S19, S20, S21, S22, S23 and S24 form an M3 electric bridge for directly measuring an axial force X; The outer side of the z-direction elastic beam of the bending and torsion element A is pasted with strain gauges numbered as S25 and S26, the outer side of the z-direction elastic beam of the bending and torsion element B is pasted with strain gauges numbered as S27 and S28, and the strain gauges numbered as S25, S26, S27 and S28 form a bending deformation measurement electric bridge M5 for measuring a lateral force Z. ​ The z-direction elastic beam of the bending-torsion element A is pasted with strain gauges numbered S29, S30, S31 and S32, and the z-direction elastic beam of the bending-torsion element B is pasted with strain gauges numbered S33, S34, S35 and S36. The eight strain gauges numbered S29, S30, S31, S32, S33, S34, S35 and S36 form a torsion deformation measuring bridge M6 for measuring the yaw moment My.

2. The high load small deflection force measuring device of claim 1, wherein, In the flat inner cavity, two tensile and compressive elements are symmetrically arranged on both sides of the bending-torsion element, and the horizontal distance between each tensile and compressive element and the bending-torsion element is equal. In the two groups of orthogonal double-cross decoupling hinges at one end of the tensile and compressive element, the transverse sides of the double-cross decoupling hinge connected with the tensile and compressive element are machined with arc-shaped grooves, the longitudinal sides of the double-cross decoupling hinge connected with the balance body are machined with arc-shaped grooves, and the arc-shaped grooves of the two groups of double-cross decoupling hinges are orthogonal and perpendicular.

3. The high load small deflection force measuring device of claim 1, wherein, The front end of the balance body is provided with a model interface, the model interface is provided with a positioning pin, a threaded hole and a center wiring hole, and the center wiring hole is arranged on the center axis of the balance body. The balance body is provided with a tensile and compressive wiring hole and a bending-torsion wiring hole in communication with the center wiring hole. The rear end of the balance body is provided with a support rod interface, and the support rod interface is provided with a positioning key groove and a locking wedge.

4. The high load small deflection force measuring device of claim 1, wherein, The upper surface of the balance body is provided with a reference platform, and the reference platform is provided with a lifting hole.

5. The high load small deflection force measuring device of claim 1 wherein, The balance body is provided with a patch groove for pasting strain gauges on the bending-torsion element and the tensile and compressive element.

6. A decoupling method of a high load small deformation force measuring device according to any one of claims 1 to 5, characterized in that, Comprising: First, the lift Y, the pitching moment Mz and the rolling moment Mx are decoupled, and the output of the H1 bridge is represented as: H1=(-S1+S2-S3+S4) / 4; The output of the H2 bridge is represented as: H2=(-S5+S6-S7+S8) / 4; The output of the H3 bridge is represented as: H3=(-S9+S10-S11+S12) / 4; The output of the H4 bridge is represented as: H4=(-S13+S14-S15+S16) / 4; The lift Y, the pitching moment Mz and the rolling moment Mx are 4-bridge combinations, and the decoupling gauges are M1, M2 and M4, and the calculation method is as follows: Lift Y: M1=(H1+H2+H3+H4) / 4; Pitching moment Mz: M2=(-H1-H2+H3+H4) / 4; Rolling moment Mx: M4=(-H1+H2-H3+H4) / 4; Then, since the decoupling design has been completed on the structure, the axial force X, the lateral force Z and the yaw moment My are directly measured by the bridges M3, M5 and M6 respectively; wherein S17~S28 adopts a single-axis strain gauge, and S29~S36 adopts a half-bridge strain gauge; the strain gauge bridge and signal output are represented as follows: Axial force X: M3=(S17-S18-S19+S20+ S21-S22-S23+S24) / 8; Lateral force Z: M5=(-S25+S26+S27-S28) / 4; Yaw moment My: M6=(S29-S30-S31+S32+S33-S34-S35+S36) / 8; The three-dimensional model of the high-load small deformation measuring device is established, including the numbered strain gauges at each patch, is imported into the finite element simulation software, each load step load and boundary condition are set according to the load condition, the mesh is divided and solved; in the post-processing, the average strain of each strain gauge at each load step is extracted through the batch processing script.

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