Inductive six-dimensional force sensor

Abstract

The application relates to the technical field of multi-dimensional sensing devices, and discloses an inductive six-dimensional force sensor, wherein the sensing targets are fixedly installed on the stress end of an elastic body; the inductive module comprises three groups of horizontal coils and three groups of vertical coils, and the six groups of coils are independently wired and independently signal output; the horizontal coils and the vertical coils are alternately and correspondingly arranged with the sensing targets, the horizontal coils are fixed on the side surface of the sensing targets, and the vertical coils are fixed on the bottom surface of the sensing targets. External loads act on the elastic body, the elastic body is elastically deformed and drives the rigid sensing targets to displace, the air gap between the sensing targets and the coils changes with the displacement, and then the inductance value of the coils is changed, and the values of the spatial six-dimensional force and moment are obtained by collecting the inductance signals. The layout can realize independent sensing of the spatial six-dimensional force and moment, effectively reduces the coupling degree of the signals in each dimension, and improves the six-dimensional force calculation precision.

Description

Technical Field

[0001] This invention relates to the field of multidimensional sensing equipment technology, and in particular to an inductive six-dimensional force sensor. Background Technology

[0002] Six-dimensional force sensors can be used to simultaneously detect three-dimensional forces and torques in space, and are core sensing components for equipment such as robots, intelligent manufacturing, and precision testing. Currently, the mainstream six-dimensional force sensors on the market are mainly divided into three categories: strain gauge type, piezoelectric type, and inductive type. Among them, inductive sensors, with their advantages of simple structure, strong anti-interference ability, fast dynamic response, and moderate cost, have been widely used in industrial precision assembly, robot end-effector force control, automated equipment load detection, and precision measurement and control scenarios. They can be used to simultaneously detect force and torque signals in six degrees of freedom in space.

[0003] Existing inductive six-dimensional force sensors have significant drawbacks. For example, the coil layout of traditional inductive six-dimensional force sensors is messy. Most products use a single group or disordered coil arrangement. The unreasonable coil array layout leads to severe coupling in the six-dimensional force dimension, causing problems such as difficulty in decoupling, low measurement accuracy, and inability to achieve accurate detection in all dimensions. Summary of the Invention

[0004] The purpose of this invention is to provide an inductive six-dimensional force sensor.

[0005] To achieve this objective, the present invention adopts the following technical solution: Inductive six-dimensional force sensor, including: A conduction module, comprising an elastomer and six sensing targets, each of which is fixed to one end of the elastomer; The inductor module includes three sets of horizontal coils and three sets of vertical coils. The horizontal coils and the vertical coils are alternately arranged to correspond one-to-one with the sensing target. The horizontal coils are fixed to the side of the sensing target, and the vertical coils are fixed to the bottom of the sensing target.

[0006] As an optional technical solution for an inductive six-dimensional force sensor, the three sensing targets corresponding to the horizontal coil are arranged at 120° intervals along the circumference, and the three sensing targets corresponding to the vertical coil are arranged at 120° intervals along the circumference.

[0007] As an optional technical solution for an inductive six-dimensional force sensor, the elastic body is provided with three crossbeams. The three crossbeams extend radially from the axis of the elastic body and are spaced 120° apart in the circumferential direction. A hollow is provided between two adjacent crossbeams.

[0008] As an optional technical solution for an inductive six-dimensional force sensor, the three sensing targets corresponding to the horizontal coil are set as square bodies, and the three sensing targets corresponding to the vertical coil are set as cylinders.

[0009] As an optional technical solution for an inductive six-dimensional force sensor, the horizontal coil is configured as a rectangular coil and the vertical coil is configured as a circular solenoid coil.

[0010] As an optional technical solution for an inductive six-dimensional force sensor, the air gap between the horizontal coil and the corresponding sensing target is less than 1 mm, and the air gap between the vertical coil and the corresponding sensing target is less than 1 mm.

[0011] As an optional technical solution for an inductive six-dimensional force sensor, both the horizontal coil and the vertical coil are multi-layer coil winding structures, and the winding directions between the layers of the multi-layer coil winding structure are the same.

[0012] As an optional technical solution for an inductive six-dimensional force sensor, the number of turns of the horizontal coil and the number of turns of the vertical coil are both proportional to the accuracy to be measured.

[0013] As an optional technical solution for an inductive six-dimensional force sensor, the elastomer is made of 7-series aluminum alloy.

[0014] As an optional technical solution for an inductive six-dimensional force sensor, the sensing target is made of metal.

[0015] The beneficial effects of this invention are: The inductive six-dimensional force sensor provided by this invention includes a conduction module and an inductance module. The conduction module includes an elastic body and six sensing targets, all of which are fixedly installed on the force-bearing end of the elastic body. To achieve effective decoupling and resolve the force and torque in six dimensions, at least six inductance values ​​are required as independent variables. Therefore, the inductance module includes three sets of horizontal coils and three sets of vertical coils, for a total of six sets of coils. Each set of coils has independent wiring and independent signal output. The horizontal and vertical coils are alternately set to correspond one-to-one with the sensing targets. The horizontal coils are fixed to the side of the sensing targets, and the vertical coils are fixed to the bottom surface of the sensing targets. An external load is applied to the elastic body, causing elastic deformation and displacement of the rigid sensing targets. The air gap between the sensing targets and the coils changes with the displacement, thereby changing the inductance value of the coils. The values ​​of the six-dimensional force and torque in space are obtained by collecting the inductance signals. This layout can realize independent sensing of the force and torque in six degrees of freedom in space, effectively reducing the signal coupling in each dimension and improving the accuracy of six-dimensional force calculation. Attached Figure Description

[0016] Figure 1 This is a first-view structural schematic diagram of the inductive six-dimensional force sensor provided in a specific embodiment of the present invention; Figure 2 This is a second-view structural schematic diagram of the inductive six-dimensional force sensor provided in a specific embodiment of the present invention.

[0017] In the picture: 100. Conducting module; 110. Elastomer; 111. Crossbeam; 120. Sensing target; 200. Inductor module; 210. Horizontal coil; 220. Vertical coil. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0019] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0021] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0022] like Figure 1 and Figure 2As shown, this invention discloses an inductive six-dimensional force sensor, including a conduction module 100 and an inductance module 200. The conduction module 100 includes an elastic body 110 and six sensing targets 120, all of which are fixedly installed on the force-bearing end of the elastic body 110. In order to achieve effective decoupling and analyze the force and torque in six dimensions, at least six inductance values ​​are required as independent variables. Therefore, the inductance module 200 includes three sets of horizontal coils 210 and three sets of vertical coils 220, for a total of six sets of coils. The six sets of coils are independently wired and have independent signal outputs. The horizontal coils 210 and vertical coils 220 are alternately set to correspond one-to-one with the sensing targets 120. The horizontal coils 210 are fixed on the side of the sensing targets 120, and the vertical coils 220 are fixed on the bottom surface of the sensing targets 120. An external load is applied to the elastic body 110, causing it to deform elastically and displace the rigid sensing target 120. The air gap between the sensing target 120 and the coil changes with the displacement, thereby altering the inductance of the coil. By acquiring the inductance signal, the values ​​of the six-dimensional force and torque in space are calculated. This arrangement enables independent sensing of the force and torque in six degrees of freedom in space, effectively reducing signal coupling in each dimension and improving the accuracy of the six-dimensional force calculation. Leveraging the inherent advantages of inductive sensing and combined with an optimized magnetic field structure, this inductive six-dimensional force sensor operates more stably in complex electromagnetic environments compared to strain gauges and piezoelectric sensors, and its signal anti-interference capability is stronger.

[0023] For example, the inductive six-dimensional force sensor can also be integrated and optimized by means of optimizing the coil array arrangement, unifying the winding rules between coil layers, matching the number of coil turns, limiting the air gap working range, selecting the best elastomer 110 material and controlling the maximum deformation, so as to achieve high-precision and high-sensitivity detection and reasonable layout of six-dimensional force.

[0024] In this embodiment, three sensing targets 120 corresponding to the horizontal coil 210 are arranged at 120° intervals along the circumference, and three sensing targets 120 corresponding to the vertical coil 220 are also arranged at 120° intervals along the circumference. Similarly, the horizontal coil 210 and the vertical coil 220 are also arranged in a uniform array at 120° circumferential angles. The coil and the sensing targets 120 are designed to be synchronized with the deformation tendency of the elastic body 110. The elastic body 110 is provided with three crossbeams 111, all of which extend radially from the axis of the elastic body 110 and are arranged at 120° intervals along the circumference. A cutout is provided between two adjacent crossbeams 111, which allows the change in coil inductance to be obtained from the change in displacement of the sensing targets 120 after accurately capturing the deformation.

[0025] Specifically, both the horizontal coil 210 and the vertical coil 220 are multi-layer coil winding structures, with the winding direction between the layers being the same. Compared to the existing technology where the winding direction between layers in multi-layer coil winding is not uniformly standardized, resulting in problems such as chaotic current directions in adjacent coils, mutual cancellation of magnetic fields, weak inductive response, and low overall sensor sensitivity, the inductive six-dimensional force sensor of this application maintains a uniform winding direction for all layers of coil winding structures. This ensures that the current direction of each layer of winding is completely consistent after the coil is energized. The uniform current direction allows the magnetic fields generated by the multi-layer coils to be effectively superimposed in the same direction, avoiding mutual cancellation of magnetic fields, increasing the overall magnetic flux of the coil, amplifying the inductive fluctuations caused by air gap changes, and maximizing the inductive response capability of the coil and the basic sensitivity of the sensor.

[0026] Understandably, the number of coil turns should be systematically optimized and matched based on the on-site usage scenario and overall installation dimensions (operating conditions). Utilizing the correlation between the number of coil turns and sensitivity, different detection accuracy requirements can be adapted as needed. Experimental fitting verification shows that when the coil structure and air gap conditions are fixed, the number of coil turns N and sensor sensitivity exhibit a positively correlated, approximately linear relationship. For scenarios requiring high sensitivity, the number of coil turns can be appropriately increased; for compact installation scenarios, the number of coil turns can be reduced while ensuring sensitivity meets the requirements. This achieves the optimal match between the number of coil turns and the operating conditions. Combining the positive correlation between the number of coil turns and sensitivity, the number of turns can be configured as needed, balancing installation dimensions and detection sensitivity. The number of coil turns can be flexibly adjusted according to equipment size and detection accuracy. The overall structure is compact and can be widely used in various scenarios such as robotics, automated production lines, and precision testing, offering greater adaptability.

[0027] In this embodiment, the number of turns of both the horizontal coil 210 and the vertical coil 220 is directly proportional to the accuracy to be measured. For low-precision, compact equipment, fewer coil turns should be selected to reduce the coil volume and adapt to limited installation space; for high-precision detection equipment, the number of coil turns should be appropriately increased to utilize the positive correlation between the number of coil turns and sensitivity to improve the resolution of weak force signals.

[0028] For example, the three sensing targets 120 corresponding to the horizontal coil 210 are set as square bodies, the horizontal coil 210 is set as a rectangular coil, and the three horizontal coils 210 are all attached to one side of the corresponding sensing target 120; the three sensing targets 120 corresponding to the vertical coil 220 are set as cylinders, the vertical coil 220 is set as a circular spiral coil, and the sensing is attached to the bottom of the cylinder.

[0029] Furthermore, the air gap (GAP) between the coil and the sensing target 120 is a core parameter affecting the sensitivity of the inductive sensor. Experiments have shown that when the air gap exceeds 1mm, the sensor sensitivity decreases significantly, the signal output becomes unstable, the calibration difficulty increases dramatically, and the calibration effect fails. Therefore, controlling the air gap operating range is a key aspect of setting up an inductive six-dimensional force sensor. With a fixed number of coil turns and a fixed structure for the sensing target 120, the variation of inductance and sensor sensitivity with the air gap is as follows: the closer the sensing target 120 is to the coil, the smaller the air gap, and the higher the sensor sensitivity; when the air gap exceeds 1mm, the sensitivity decreases rapidly, and the sensor calibration effect deteriorates significantly or even fails. To ensure stable and reliable calibration performance, the displacement of the sensing target 120 is controlled by the deformation of the elastic body 110, so that the working air gap is always less than 1mm. This avoids the defects of sensitivity attenuation and calibration failure under large gaps, resulting in better calibration consistency of the inductive six-dimensional force sensor across the entire range. Therefore, when the inductive six-dimensional force sensor is working normally, the air gap between the coil and the sensing target 120 is always controlled within the high sensitivity range of less than 1mm, that is, the air gap between the horizontal coil 210 and the vertical coil 220 and the corresponding sensing target 120 is less than 1mm.

[0030] As the core component for force transmission, the elastomer 110, if made of ordinary materials, will cause the displacement of the sensing target 120 to exceed the high-sensitivity air gap range if the deformation is too large; conversely, if the deformation is too small, the sensor's range will be insufficient. Furthermore, elastomers made of ordinary materials are prone to plastic deformation and fatigue aging, shortening the equipment's lifespan. Therefore, considering the maximum deformation of the elastomer 110 and the maximum bidirectional displacement of the sensing target 120, a 7-series aluminum alloy was selected as the material for the elastomer 110, while the sensing target 120 is made of metal. Under this structure, the maximum elastic deformation of the elastomer 110 made of this material is ±0.12mm. This deformation range ensures that the displacement of the sensing target 120 caused by the deformation of the elastomer 110 remains within the preset high-sensitivity air gap range. After assembly, the initial air gap between the coil and the sensing target 120 is set within a reasonable range. When the elastic body 110 is subjected to load and undergoes positive or negative deformation, the maximum displacement of the sensing target 120 is limited to ±0.12mm. The corresponding air gap change range is always less than 1mm, ensuring that the inductive six-dimensional force sensor operates in a high-sensitivity range throughout its operation. This ensures the range of the inductive six-dimensional force sensor while avoiding sensitivity reduction and calibration failure caused by excessive air gap. Furthermore, the 7-series aluminum alloy possesses high strength, fatigue resistance, and good deformation recovery characteristics, exhibiting no plastic deformation under long-term repeated deformation, thus extending the service life of the inductive six-dimensional force sensor and making it suitable for long-term continuous industrial operation scenarios.

[0031] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. An inductive six-dimensional force sensor, characterized in that, include: The transmission module (100) includes an elastomer (110) and six sensing targets (120), each of which is fixed to one end of the elastomer (110). An inductor module (200) includes three sets of horizontal coils (210) and three sets of vertical coils (220). The horizontal coils (210) and the vertical coils (220) are alternately arranged in correspondence with the sensing target (120). The horizontal coils (210) are fixed to the side of the sensing target (120), and the vertical coils (220) are fixed to the bottom of the sensing target (120).

2. The inductive six-dimensional force sensor according to claim 1, characterized in that, The three sensing targets (120) corresponding to the horizontal coil (210) are arranged at 120° intervals along the circumference, and the three sensing targets (120) corresponding to the vertical coil (220) are arranged at 120° intervals along the circumference.

3. The inductive six-dimensional force sensor according to claim 2, characterized in that, The elastic body (110) is provided with three crossbeams (111), all three crossbeams (111) extending radially from the axis of the elastic body (110) and spaced 120° apart in the circumferential direction, and a hollow is provided between two adjacent crossbeams (111).

4. The inductive six-dimensional force sensor according to claim 1, characterized in that, The three sensing targets (120) corresponding to the horizontal coil (210) are set as square bodies, and the three sensing targets (120) corresponding to the vertical coil (220) are set as cylinders.

5. The inductive six-dimensional force sensor according to claim 4, characterized in that, The horizontal coil (210) is configured as a rectangular coil, and the vertical coil (220) is configured as a circular spiral coil.

6. The inductive six-dimensional force sensor according to claim 1, characterized in that, The air gap between the horizontal coil (210) and the corresponding sensing target (120) is less than 1 mm, and the air gap between the vertical coil (220) and the corresponding sensing target (120) is less than 1 mm.

7. The inductive six-dimensional force sensor according to claim 1, characterized in that, Both the horizontal coil (210) and the vertical coil (220) are multi-layer coil winding structures, and the winding directions between the layers of the multi-layer coil winding structure are the same.

8. The inductive six-dimensional force sensor according to claim 1, characterized in that, The number of turns of the horizontal coil (210) and the number of turns of the vertical coil (220) are both proportional to the accuracy to be measured.

9. The inductive six-dimensional force sensor according to claim 1, characterized in that, The elastomer (110) is made of 7-series aluminum alloy.

10. The inductive six-dimensional force sensor according to claim 1, characterized in that, The sensing target (120) is made of metal.

Images