Torque detection device

Abstract

This application discloses a torque detection device, comprising: a strain gauge for deforming under torque; a first strain gauge fixed on the strain gauge, the permeability of which varies with the strain applied to it; a circuit board having at least one first planar coil and the same number of second planar coils as the first planar coil; a second strain gauge disposed on the side of the circuit board away from the first strain gauge, and having the same structure and material as the first strain gauge; and a dielectric layer disposed between the circuit board and the second strain gauge; wherein the first planar coil is disposed opposite to the first strain gauge; the second planar coil is disposed opposite to the second strain gauge; and the thickness and dielectric constant of the dielectric layer are set such that the inductance parameter of the second planar coil responds to temperature changes in a manner that matches the inductance parameter of the first planar coil responds to temperature changes.

Description

Technical Field

[0001] This application relates to the field of sensors, and in particular to a torque detection device. Background Technology

[0002] As embodied intelligence is increasingly applied across various scenarios, the demands on its perception systems are also rising. Improving a robot's perception capabilities to ensure it doesn't cause harm to the user is a crucial factor determining its scope of application.

[0003] To prevent robots from causing harm to the surrounding environment, especially people, during movement, current mainstream solutions incorporate torque monitoring into motion control, triggering a motion pause alarm when the torque is too high. As robot applications become increasingly diverse, adding torque sensors has gradually become the mainstream torque monitoring solution. Currently, the mainstream torque sensor solution primarily uses metal resistance strain gauges. This involves attaching a metal resistance strain gauge to a strain gauge; when the strain gauge deforms, the resistance of the strain gauge changes, and this change is then converted into an electrical signal by subsequent circuitry. In this solution, the strain gauge needs to be connected to the motherboard via wire bonding or soldering, and the motherboard's signal is then transmitted to the robot's main control module. This solution requires ensuring the bending and tensile strength of the motherboard signal lines and confirming cable quality during robot movement. Furthermore, the manufacturing process also requires wire bonding or soldering, and the electrical connections must be protected. Both of these factors significantly increase the cost of torque products and hinder the expansion of robot application scenarios.

[0004] In addition to using metal resistance strain gauges, there is also a MEMS silicon-based strain gauge solution, but it still uses resistance strain gauges, which require the strain gauge to be connected to the main circuit as a variable resistor. The two problems mentioned above still cannot be effectively solved.

[0005] Besides the two methods mentioned above, there is also the method of measuring the angles at both ends of the torsion bar and calculating the torque by combining the stress-strain curve of the torsion bar. However, due to its complex structure, irreversible damage to the torsion bar, and difficulty in maintenance, this method has not become the mainstream solution.

[0006] In summary, the current mainstream torque sensor solution still uses a strain material (such as a metal resistance strain gauge or MEMS strain gauge) as the strain resistor connected in the circuit. However, regardless of the material, two problems remain unavoidable: one is that the overall stress can only be determined by measuring the torque in a small area of ​​the strained material; the other is that the resistance changes with changes in external temperature, i.e., the temperature drift problem. To solve the temperature drift problem, current methods mainly involve measuring each product at different temperatures before compensation. With this approach, changes in product shape alter the temperature drift curve, and stability needs improvement. Summary of the Invention

[0007] To address the temperature drift problem during measurement and to increase the measurable area of ​​the strain body, this application proposes a torque detection device.

[0008] The torque detection device includes: a strain gauge for deforming under torque; a first strain gauge fixed to the strain gauge, the permeability of which varies with the strain it receives; a circuit board having at least one first planar coil and the same number of second planar coils as the first planar coil; a second strain gauge disposed on the side of the circuit board away from the first strain gauge, and the second strain gauge having the same structure and material as the first strain gauge; and a dielectric layer disposed between the circuit board and the second strain gauge. The first planar coil is disposed opposite to the first strain gauge to change its inductance parameter based on the change in permeability of the first strain gauge; the second planar coil is disposed opposite to the second strain gauge to change its inductance parameter based on the change in permeability of the second strain gauge; the torque received by the strain gauge is calculated based on the changes in the inductance parameters of the first and second planar coils; and the thickness and dielectric constant of the dielectric layer are set such that the response of the inductance parameter of the second planar coil to temperature changes matches the response of the inductance parameter of the first planar coil to temperature changes.

[0009] Optionally, the first strain gauge and the second strain gauge are made of a contramagnetic-strictive material.

[0010] Optionally, the dimagnetostrictive material includes an amorphous alloy.

[0011] Optionally, the first strain gauge and the second strain gauge have the same patterned structure; wherein the patterned structure of the first strain gauge corresponds spatially to the first planar coil, and the patterned structure of the second strain gauge corresponds spatially to the second planar coil.

[0012] Optionally, the patterned structure includes a first region and a second region, wherein when the strained body is subjected to torque, the first region and the second region produce permeability changes with opposite trends and generate two differential voltage signals, and the torque is calculated by detecting the two differential voltage signals.

[0013] Optionally, the patterned structure includes multiple metal cutout areas.

[0014] Optionally, the dielectric layer is a gasket made of a low dielectric constant material.

[0015] Optionally, the thickness of the gasket is set such that the distance between the first strain gauge and the circuit board is equal to the distance between the second strain gauge and the circuit board.

[0016] Optionally, the strain gauge is a disc structure having an inner ring connecting portion and an outer ring connecting portion that are respectively connected to the upper power input shaft and the lower power output shaft, and the first strain gauge is fixed between the inner ring connecting portion and the outer ring connecting portion.

[0017] Optionally, the first strain gauge is fixed to the surface of the strained material by bonding, magnetron sputtering or deposition, and the second strain gauge is fixed to the surface of the gasket by bonding, magnetron sputtering or deposition.

[0018] Optionally, on the first strain gauge, the first region is an inner circumferential region and the second region is an outer circumferential region, wherein an inner coil corresponding to the inner circumferential region and an outer coil corresponding to the outer circumferential region are formed in the circumferential direction of the circuit board.

[0019] Optionally, the first strain gauge includes a plurality of first regions and a plurality of second regions, wherein the plurality of first regions and the plurality of second regions are alternately distributed in the circumferential direction of the first strain gauge, and wherein a plurality of coils corresponding one-to-one with the plurality of first regions and the plurality of second regions are formed in the circumferential direction of the circuit board.

[0020] Therefore, this application achieves temperature drift correction of the first strain gauge by setting a second strain gauge with the same structure and material as the first strain gauge and at the same distance from the circuit board. Furthermore, the patterned structure set circumferentially on the first strain gauge ensures that the entire first strain gauge is a measurable area.

[0021] Furthermore, compared to traditional MEMS or metal resistance strain gauge solutions that employ single-point measurement, this application uses regional deformation measurement, which avoids single-point position measurement distortion caused by component manufacturing issues. It also avoids restrictions on robot joint movement caused by introducing excessive cabling. Attached Figure Description

[0022] Figure 1 This is an exploded view of a torque detection device according to an embodiment of this application.

[0023] Figure 2 This is a schematic diagram of a strain body according to an embodiment of this application.

[0024] Figure 3 This is a schematic diagram of a first strain gauge and a circuit board according to an embodiment of this application, wherein (a) is a schematic diagram of a first strain gauge in a single-layer metal hollow area, (b) is a schematic diagram of a circuit board corresponding to the first strain gauge and a first planar coil thereon, and (c) is a schematic diagram of the first strain gauge and the circuit board.

[0025] Figure 4 This is a schematic diagram of a torque detection device according to another embodiment of the present application, wherein (a) is a schematic diagram of a first strain gauge with multiple metal hollow areas, (b) is a schematic diagram of a circuit board corresponding to the first strain gauge and a first planar coil thereon, and (c) is an exploded view of a torque detection device provided with the first strain gauge and the circuit board. Detailed Implementation

[0026] The torque detection device proposed in this application will now be described in conjunction with the accompanying drawings.

[0027] Figure 1 This is an exploded view of the torque detection device proposed in this application. Figure 1 As shown, the torque detection device includes a strain gauge 1, a first strain gauge 2, a circuit board 3, a dielectric layer (shown as a gasket 4 in the accompanying drawings according to an embodiment of this application), and a second strain gauge 5.

[0028] Strain gauge 1 is designed to deform under torque. In one embodiment, strain gauge 1 is a disc structure, more particularly a metal disc. Figure 2 As shown, strain gauge 1 has an inner ring connecting portion 11 and an outer ring connecting portion 12, which can be, for example, connecting holes. The inner ring connecting portion 11 and the outer ring connecting portion 12 are respectively connected to the upper-level power input shaft and the lower-level power output shaft of the robot. For example, the inner ring connecting portion 11 is connected to the upper-level power input shaft, and the outer ring connecting portion 12 is connected to the lower-level power output shaft, or the inner ring connecting portion 11 is connected to the lower-level power output shaft, and the outer ring connecting portion 12 is connected to the upper-level power input shaft. Therefore, when the robot moves, strain gauge 1, located at the joint, will simultaneously bear torques applied in opposite directions by the upper-level power input shaft and the lower-level power output shaft, which will act on the inner ring connecting portion 11 and the outer ring connecting portion 12 respectively.

[0029] The first strain gauge 2 is fixed to the strain vessel 1, particularly between the inner ring connecting portion 11 and the outer ring connecting portion 12 of the strain vessel 1, for example, by bonding, magnetron sputtering, or deposition. The first strain gauge 2 is made of a contramagnetostrictive material (e.g., an amorphous alloy) and has a patterned structure 21, such as a metal cutout area. When the strain vessel 1 is subjected to torque, the torque is transmitted to the first strain gauge 2, causing the first strain gauge to deform, thereby changing the magnetic permeability of the first strain gauge 2.

[0030] The circuit board 3 is fixed in relative position to the first strain gauge 2, and can be attached to the first strain gauge 2, but preferably with a certain gap. The circuit board 3 can be fixed to the strain gauge 1 or to the mounting platform. Simultaneously, the circuit board 3 is provided with at least one first planar coil and the same number of second planar coils as the first planar coil. The first planar coils are located on one side of the circuit board 3, opposite to the first strain gauge 2, and further spatially correspond to the patterned structure of the first strain gauge 2. The second planar coils are located on the other side of the circuit board 3, opposite to the second strain gauge 5, and further spatially correspond to the patterned structure of the second strain gauge 5. When the permeability of the first strain gauge 2 changes, it changes the inductance value of the first planar coil. The change in inductance value causes a change in the resonant frequency in the circuit, thereby generating a voltage change; similarly, the change in the permeability of the second strain gauge 5 changes the inductance value of the second planar coil, and generates a voltage change. The change in the permeability of the first strain gauge is caused by torque and temperature, while the change in the permeability of the second strain gauge is caused by temperature. The torque can be calculated in the subsequent calculation circuit based on the voltage change caused by the first and second strain gauges.

[0031] The metal cutout area can have any suitable shape, such as a single-layer metal cutout area, a multi-layer metal cutout area, or multiple metal cutout areas.

[0032] like Figure 3 As shown in (a), when there is only one layer of metal hollow area, if the outer ring is subjected to a clockwise torque and the inner ring is subjected to a counterclockwise torque, the metal hollow area is stretched and the permeability changes accordingly; if the outer ring is subjected to a counterclockwise torque and the inner ring is subjected to a clockwise torque, the metal hollow area is compressed and the permeability changes in the opposite way. Figure 3 (b) shows the circuit board corresponding to the single-layer metal cutout area and the single-layer first planar coil on it. The first planar coil corresponds spatially to the single-layer metal cutout area, as shown below. Figure 3 As shown in (c).

[0033] When there are multiple layers of metal cutout areas or multiple pieces of metal cutout areas, the metal cutout areas can be divided into a first area and a second area.

[0034] like Figure 4 As shown in (a), when multiple metal cutout areas are included, the patterned structure 21 includes multiple first regions 22 and second regions 23 with opposite directions. The multiple first regions 22 and multiple second regions 23 are alternately distributed in the circumferential direction of the first strain gauge 2. For example, when the outer ring is subjected to a clockwise torque and the inner ring is subjected to a counterclockwise torque, the first region 22 is stretched, and the second region 23 is compressed. The first region 22 and the second region 23 produce opposite permeability changes, thereby outputting two differential voltage signals on the first planar coil, and vice versa. Correspondingly, multiple first planar coils are formed in the circumferential direction of the circuit board 3, corresponding one-to-one with the multiple first regions 22 and multiple second regions 23, and the winding directions of the first portion 24 of the first planar coil opposite to the first region and the second portion 25 of the first planar coil opposite to the second region are opposite, such as... Figure 4 As shown in (b). Figure 4 (c) is set to have Figure 4 Exploded views of the torque detection device for the first strain gauge and circuit board shown in (a) and (b).

[0035] Furthermore, the metal cutout area can also include two layers, inner and outer. For example, the first area is an inner circumference area, and the second area is an outer circumference area. The metal cutouts in the first area are arranged along a first direction (e.g., Figure 1 (As shown in the diagram, the metal cutout areas in the second region are arranged in the opposite direction to the first direction.) Correspondingly, an inner coil corresponding to the inner circumferential region and an outer coil corresponding to the outer circumferential region are formed in the circumferential direction of the circuit board. It can be understood that both the inner and outer coils are the aforementioned first planar coils. Thus, when the strain gauge is subjected to torque, the torques borne by the first region and the second region are opposite, and the resulting deformations are also opposite (compression and tension), thereby causing a change in the permeability of the first strain gauge.

[0036] Those skilled in the art will understand that by uniformly setting a patterned structure along the 360° circumference of the strain body, the entire strain body can be used for torque detection, rather than only a portion of it. However, a patterned structure can also be set in a portion of the circumference of the strain body to achieve the same torque detection function. Furthermore, methods similar to... Figure 3 , Figure 4 Different perforated patterns are acceptable, as long as they can produce changes in magnetic permeability.

[0037] A dielectric layer is disposed between circuit board 3 and the second strain gauge 5. The dielectric layer can be an air layer or a solid structure, for example... Figure 1The gasket 4 is shown in the diagram. When the dielectric layer is a solid structure, it is fixed to the circuit board 3, for example, including but not limited to adhesive bonding. Thus, one side of the circuit board 3 faces the first strain gauge 2, and the other side faces the gasket 4. The second strain gauge 5 is fixed to the gasket 4, for example, including but not limited to adhesive bonding, magnetron sputtering, or deposition. Thus, one side of the gasket 4 faces the circuit board 3, and the other side faces the second strain gauge 5. Furthermore, the material and structure of the second strain gauge 5 are the same as those of the first strain gauge 2, ensuring that the permeability changes of the second strain gauge 5 and the first strain gauge 2 due to temperature are the same.

[0038] Since the inductance values ​​of the first and second planar coils are related not only to the permeability changes of the first and second strain gauges, but also to the "transmission path" through which the permeability change is transmitted to the first and second planar coils, i.e., to the dielectric layer, it is necessary not only to design the second strain gauge to have the same material and structure as the first strain gauge, but also to ensure that the changes in inductance parameters of the first and second planar coils in response to temperature changes are identical after sensing the permeability change information "transmitted" in the dielectric layer. The "transmission path" is related to the thickness of the dielectric layer (the distance between the corresponding strain gauge and the corresponding coil) and its dielectric constant. Therefore, the thickness and dielectric constant of the dielectric layer need to be set so that the response of the inductance parameters of the second planar coil to temperature changes matches the response of the inductance parameters of the first planar coil to temperature changes. In this embodiment, the thickness of the spacer 4 can be set such that the distance between the second strain gauge 5 and the circuit board 3 is equal to the distance between the first strain gauge 2 and the circuit board 3. Simultaneously, the spacer 4 is made of a material with a low dielectric constant, such as a material with a dielectric constant close to that of air, thereby avoiding the introduction of additional electrical interference. In this embodiment, gasket 4 is used as the dielectric layer, but it is understood that any dielectric layer that can achieve the above function can be used.

[0039] With the above setup, when the temperature changes, the change in permeability generated by the second strain gauge 5 causes a change in inductance in the second planar coil, ultimately resulting in a voltage change. This voltage change can be used to calculate the temperature-induced change in permeability of the second strain gauge 5. The first strain gauge 2, compared to the second strain gauge 5, has the same structure and material, and the same "transmission path" for the permeability change induced by the corresponding planar coil on the circuit board. Therefore, the temperature-induced permeability changes sensed by the first and second planar coils are also the same. Thus, the calculated permeability change of the second strain gauge 5 is equivalent to the temperature-induced permeability change of the first strain gauge 2. This allows for temperature compensation correction of the torque detection of the first strain gauge 2 based on the second strain gauge 5, effectively avoiding temperature drift problems. For example, if the voltage change generated by the second planar coil is denoted as U1, and the voltage change generated by the first planar coil is denoted as U2, then U2 - U1 yields the voltage change of the first planar coil in response to the torque on the first strain gauge, and the torque can then be calculated from this.

[0040] Understandably, to ensure the accuracy of temperature drift correction, the second strain gauge needs to maintain the same structure as the first strain gauge as much as possible. Therefore, the metal cutout area of ​​the second strain gauge can also be as follows: Figure 3 , Figure 4 As shown, this is consistent with the first strain gauge. Simultaneously, the structure and arrangement of the first and second planar coils should also correspond. And from... Figure 1 and Figure 4 As can be seen in (c), the second strain gauge, the gasket, the circuit board (especially the first planar coil and the second planar coil on the circuit board) and the first strain gauge are spatially aligned in the vertical direction as much as possible to improve the detection accuracy.

[0041] The specific embodiments described above illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Although the description of this application is presented in conjunction with preferred embodiments, this does not mean that the features of this invention are limited to these embodiments. Furthermore, to avoid confusion or obscuring the focus of this application, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0042] Furthermore, the various operations will be described as multiple discrete operations in a manner most conducive to understanding the illustrative embodiments; however, the order of description should not be construed as implying that these operations must depend on the order. In particular, these operations do not need to be performed in the order presented.

[0043] Unless the context otherwise specifies, the terms “contains,” “has,” and “includes” are synonyms. The phrase “A / B” means “A or B.” The phrase “A and / or B” means “(A and B) or (A or B).”

[0044] As used herein, the terms “module” or “unit” may refer to, be, or include: application-specific integrated circuits (ASICs), electronic circuits, (shared, dedicated, or group) processors and / or memories that execute one or more software or firmware programs, combinational logic circuits, and / or other suitable components that provide the described functionality.

[0045] In the accompanying drawings, certain structural or methodological features are shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. In some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular figure does not imply that such features are required in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.

[0046] It should be understood that although terms such as "first," "second," etc., may be used herein to describe various units or data, these units or data should not be limited by these terms. These terms are used merely to distinguish one feature from another. For example, without departing from the scope of the exemplary embodiments, a first feature may be referred to as a second feature, and similarly, a second feature may be referred to as a first feature.

[0047] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] Although the invention has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims

1. A torque detection device, characterized in that, include: Strain type, used to deform when subjected to torque; A first strain gauge is fixed to the strained body, and the change in magnetic permeability of the first strain gauge is caused by torque and temperature; A circuit board having at least one first planar coil and the same number of second planar coils as the first planar coil; The second strain gauge is disposed on the side of the circuit board away from the first strain gauge. The change in magnetic permeability of the second strain gauge is caused by temperature. The second strain gauge has the same structure and material as the first strain gauge, and the first strain gauge and the second strain gauge have the same patterned structure. A dielectric layer is disposed between the circuit board and the second strain gauge; wherein, The first planar coil is positioned opposite the first strain gauge to change the inductance parameters of the first planar coil based on the change in the permeability of the first strain gauge. The second planar coil is arranged opposite to the second strain gauge to change the inductance parameter of the second planar coil based on the change in the permeability of the second strain gauge, and the torque on the strain is calculated based on the changes in the inductance parameters of the first planar coil and the second planar coil. The thickness and dielectric constant of the dielectric layer are set such that the inductance parameters of the second planar coil respond to temperature changes in a manner that matches the inductance parameters of the first planar coil respond to temperature changes.

2. The torque detection device according to claim 1, characterized in that, The first strain gauge and the second strain gauge are made of a dimagnetostrictive material.

3. The torque detection device according to claim 2, characterized in that, The diamagnetic material includes amorphous alloys.

4. The torque detection device according to claim 3, characterized in that, in, The patterned structure of the first strain gauge corresponds spatially to the first planar coil, and the patterned structure of the second strain gauge corresponds spatially to the second planar coil.

5. The torque detection device according to claim 4, characterized in that, The patterned structure includes a first region and a second region. When the strained body is subjected to torque, the first region and the second region produce permeability changes with opposite trends and generate two differential voltage signals. The torque is calculated by detecting the two differential voltage signals.

6. The torque detection device according to claim 5, characterized in that, The patterned structure includes multiple metal cutout areas.

7. The torque detection device according to claim 1, characterized in that, The dielectric layer is a gasket made of a low dielectric constant material.

8. The torque detection device according to claim 7, characterized in that, The thickness of the gasket is set such that the distance between the first strain gauge and the circuit board is equal to the distance between the second strain gauge and the circuit board.

9. The torque detection device according to claim 1, characterized in that, The strain gauge is a disc structure with an inner ring connecting part and an outer ring connecting part that are respectively connected to the upper power input shaft and the lower power output shaft. The first strain gauge is fixed between the inner ring connecting part and the outer ring connecting part.

10. The torque detection device according to claim 8, characterized in that, The first strain gauge is fixed to the surface of the strained material by bonding, magnetron sputtering or deposition, and the second strain gauge is fixed to the surface of the gasket by bonding, magnetron sputtering or deposition.

11. The torque detection device according to claim 5, characterized in that, On the first strain gauge, the first region is the inner circumferential region, and the second region is the outer circumferential region. In this circuit board, an inner coil corresponding to the inner circumferential region and an outer coil corresponding to the outer circumferential region are formed in the circumferential direction.

12. The torque detection device according to claim 5, characterized in that, The first strain gauge includes multiple first regions and multiple second regions, wherein the multiple first regions and the multiple second regions are alternately distributed in the circumferential direction of the first strain gauge. In this circuit board, multiple coils are formed in the circumferential direction, each corresponding to a plurality of first regions and a plurality of second regions.

Images