Multi-dimensional force sensor

Abstract

The utility model relates to a multi-dimensional force sensor, which is structurally characterized in that a curved surface capacitor is formed by matching bending of a flexible belt with a lower electrode, a circuit board where the lower electrode is located is fixed and pre-pressed by a curved surface, the lower electrode is driven by an elastic cantilever beam to deform to generate capacitance change of each electrode, and three-dimensional force and three-dimensional torque are reflected through the capacitance change. The multi-dimensional force sensor provided by the utility model has the advantages of high sensitivity, strong stability, convenient wiring, simple structure, less calibration or even no calibration, easy calibration and the like, and can supplement six-dimensional force measurement at a facet joint.

Description

Technical Field

[0001] This utility model relates to the measurement of force and torque, and more particularly to a six-dimensional force sensor. Background Technology

[0002] Tactile sensing is divided into surface tactile sensing and force tactile sensing. Surface tactile sensing, such as electronic skin, is used to measure force, while force tactile sensing is often used in robot joints to measure both XYZ three-dimensional forces and XYZ torques, and is called a six-dimensional force sensor. Currently, most good six-dimensional force sensors are imported from abroad, priced at 60,000-100,000 RMB each, while domestically produced ones cost around 6,000-8,000 RMB. Six-dimensional force sensors have been developed both domestically and internationally for many years. Based on their operating principles, they can be classified as resistive, capacitive, photoelectric, etc. Resistive sensors were previously the mainstream, while capacitive sensors have gradually emerged in recent years. Other principles are basically not yet in mass production.

[0003] Resistive force sensors, implemented using strain gauges, are bulky and heavy. While suitable for large joints like the shoulder and elbow joints of robots, they are difficult to use in smaller joints such as the finger joints. Compared to resistive sensors, capacitive six-dimensional force sensors offer significant advantages in terms of compactness and response speed. Furthermore, capacitive sensors are far more effective than strain gauges in mitigating the effects of temperature. Therefore, capacitive sensors hold the promise of becoming the mainstream technology in the future.

[0004] Current capacitive sensors primarily employ the parallel plate principle. For example, the capacitive sensor proposed in CN114659696B uses multiple parallel and perpendicular plates to form a six-dimensional force measurement, essentially adhering to the concept of parallel plate capacitance. Compared to curved surface capacitors, parallel plate capacitors suffer from drawbacks such as lower sensitivity, more complex structure, lower stability, greater calibration difficulty, and more frequent calibration (once a year). Therefore, how to achieve six-dimensional force sensing based on curved surface capacitors has become a research topic that needs further investigation. Utility Model Content

[0005] To address the shortcomings of existing technologies, a structure for implementing a multidimensional force sensor is provided.

[0006] The first type of multidimensional force sensor structure of this utility model includes an elastic cantilever beam, a base, a capacitance-to-digital conversion circuit, and a processing module. The cantilever beam is mounted on the base, and at least three circumferentially distributed flexible conductive strips are arranged below the cantilever beam. Below each conductive strip, two lower electrodes are correspondingly arranged on the left and right sides of the central axis of the conductive strip. The lower electrodes are insulated from each other, and a potential difference is formed between the conductive strips and the lower electrodes. One end of each conductive strip is connected to form a whole, and the connection point is fixed relative to the lower electrodes. The other ends are physically connected directly or indirectly to the cantilever beam for fixation. The distance between the cantilever beam and the lower electrodes is set such that the conductive strips... A conductive strip is formed by pre-pressing a bent electrode onto the lower electrode; an insulating layer is provided between the conductive strip and the lower electrode to isolate them; the projection of each conductive strip relative to the lower electrode at least synchronously covers a portion of the area of ​​each corresponding electrode below; the deformation of the cantilever beam under external force causes the conductive strip to change the indirect contact area of ​​the bent part on the lower electrode, and the circumferential torsion under external force can form a difference in the projected area and / or distance of the conductive strip relative to each corresponding electrode below; a capacitance-to-digital conversion circuit is coupled to each lower electrode to obtain the capacitance; the processing module is coupled to the capacitance-to-digital conversion circuit to output an electrical signal characterizing the force and torque based on the capacitance.

[0007] The second type of multidimensional force sensor structure of this utility model includes an elastic cantilever beam, a base, a capacitance-to-digital conversion circuit, and a processing module. The cantilever beam is mounted on the base, and at least three circumferentially distributed flexible conductive strips are arranged below the cantilever beam. Two lower electrodes are correspondingly arranged below each conductive strip, with the conductive strips spanning across the two lower electrodes. The lower electrodes are insulated from each other, and a potential difference is formed between the conductive strips and the lower electrodes. Each conductive strip is an independent unit, with one end directly or indirectly physically connected to the cantilever beam, and the other end directly or indirectly physically connected to either the cantilever beam or the lower electrode. The bottom of the conductive strip is fixed relative to the lower electrode. The cantilever beam and the lower electrode... The distance between them is set so that the conductive strip forms a bent electrode pre-pressed on the lower electrode; an insulating layer is provided between the conductive strip and the lower electrode to isolate them, and the projection of each conductive strip relative to the lower electrode at least synchronously covers part of the area of ​​each corresponding electrode below. The deformation of the cantilever beam under the action of external force causes the conductive strip to change the indirect contact area of ​​the bent part on the lower electrode, and the circumferential torsion under the action of external force can form a difference in the projected area and / or distance of the conductive strip relative to each corresponding electrode below; the capacitance-to-digital conversion circuit is coupled to each lower electrode to obtain the capacitance; the processing module is coupled to the capacitance-to-digital conversion circuit to output an electrical signal characterizing the force and torque based on the capacitance.

[0008] The third multidimensional force sensor implementation structure of this utility model includes an elastic cantilever beam, a substrate, a capacitor-to-digital converter circuit, and a processing module. At least three pairs of circumferentially distributed flexible conductive strips are arranged below the cantilever beam. The conductive strips are mutually insulated, and a lower electrode is correspondingly arranged below each pair of conductive strips. All lower electrodes share a common ground. Each pair of conductive strips is distributed on both sides of the central axis of the corresponding lower electrode, forming a potential difference between the conductive strips and the lower electrode. Each conductive strip is independently formed, with one end of each conductive strip directly or indirectly physically connected to the cantilever beam, and the other end directly or indirectly physically connected to the cantilever beam or the lower electrode. The bottom of the conductive strip is fixed relative to the lower electrode. The distance between the cantilever beam and the lower electrode is... The distance is set such that the conductive strip forms a bent electrode pre-pressed onto the lower electrode; an insulating layer is provided between the conductive strip and the lower electrode to isolate them; the projection of the lower electrode relative to the conductive strip at least synchronously covers a portion of the area of ​​each corresponding conductive strip above; the deformation of the cantilever beam under external force causes the conductive strip to change the indirect contact area of ​​the bent part on the lower electrode, and the difference in the projected area and / or distance of the component forming the lower electrode relative to each corresponding conductive strip above is caused by the circumferential torsion of the external force; a capacitance-to-digital conversion circuit is coupled to each conductive strip to obtain capacitance; the processing module is coupled to the capacitance-to-digital conversion circuit to output an electrical signal characterizing the force and torque based on the capacitance.

[0009] The fourth multidimensional force sensor implementation structure of this utility model includes an elastic cantilever beam, a substrate, a capacitor-to-digital converter circuit, and a processing module. At least three pairs of circumferentially distributed flexible conductive strips are arranged below the cantilever beam. The conductive strips are mutually insulated, and a lower electrode is correspondingly arranged below each pair of conductive strips. All lower electrodes share a common ground. Each pair of conductive strips is distributed on both sides of the central axis of the corresponding lower electrode, forming a potential difference between the conductive strips and the lower electrode. One end of each conductive strip is connected by an insulating component, and the connection point is fixed relative to the lower electrode. The other end is physically connected directly or indirectly to the cantilever beam for fixation. The distance between the cantilever beam and the lower electrode is set such that the conductive strips... A curved electrode is formed by pre-pressing the conductive strip onto the lower electrode; an insulating layer is provided between the conductive strip and the lower electrode for isolation; the projection of the lower electrode relative to the conductive strip at least synchronously covers a portion of the area of ​​each corresponding conductive strip above; the deformation of the cantilever beam under external force causes the conductive strip to change the indirect contact area of ​​the curved part on the lower electrode, and the circumferential torsion under external force can form a difference in the projected area and / or distance of the lower electrode arm relative to each corresponding conductive strip above; a capacitance-to-digital conversion circuit is coupled to each conductive strip to obtain capacitance; the processing module is coupled to the capacitance-to-digital conversion circuit to output an electrical signal characterizing the force and torque based on the capacitance.

[0010] The multi-dimensional force sensor of this invention has advantages such as high sensitivity, strong stability, convenient wiring, simple structure, low or no calibration, and easy calibration. It can supplement the six-dimensional force measurement at small joints. Attached Figure Description

[0011] Figure 1a This illustrates the first design style of the cantilever beam. Figure 1b This illustrates the second design style. Figure 1c This illustrates the third design style.

[0012] Figure 2a The schematic diagram illustrates the overall structure of the first type of multidimensional force sensor of this utility model. Figure 2b The cross-section of the first type of multidimensional force sensor is shown. Figure 2c The structure of the hidden substrate of the first type of multidimensional force sensor is illustrated. Figure 2d The diagram illustrates the relative relationships between the electrodes in the first type of multidimensional force sensor. Figure 2e This diagram illustrates how the conductive strip is fixed to the circuit board.

[0013] Figure 3a This diagram illustrates the structure of the second type of multidimensional force sensor of this invention after it is hidden from the substrate. Figure 3b The cross-section of the second type of multidimensional force sensor is shown. Figure 3c This diagram illustrates a three-dimensional perspective showing the relative relationship between the U-shaped conductive strip and the lower electrode in the second type of multidimensional force sensor. Figure 3d This illustrates a bird's-eye view.

[0014] Figure 4a The diagram illustrates a three-dimensional perspective showing the relative relationship between the laterally suspended conductive strip and the lower electrode in the second type of multidimensional force sensor. Figure 4b The cross-sectional view is shown.

[0015] Figure 5a This diagram illustrates the structure of the third type of multidimensional force sensor of this invention after it is hidden from the substrate. Figure 5b The cross-section of the third type of multidimensional force sensor is shown. Figure 5c This is a stereoscopic view illustrating the first relative relationship between the U-shaped conductive strip and the lower electrode in the third type of multidimensional force sensor.

[0016] Figure 6a This is a stereoscopic view illustrating the second relative relationship between the U-shaped conductive strip and the lower electrode in the third type of multidimensional force sensor.

[0017] Figure 7a This diagram illustrates the design of the electrode under the strip plane. Figure 7b The design of the electrode under the sector-shaped plane is illustrated.

[0018] Figure 8a The diagram illustrates the cross-sectional structure of the sensor when the lower electrode is a curved electrode. Figure 8b The three-dimensional structure of the electrode under the curved surface is shown. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0020] This invention provides various structures for implementing multidimensional force sensors. The common feature of each structure is that the lower electrode forms a curved capacitor by bending a flexible strip. The curved surface is fixed and pre-pressed onto the circuit board where the lower electrode is located. Under the action of an elastic cantilever beam, the deformation generates changes in the capacitance of each electrode. The changes in capacitance reflect three-dimensional force and three-dimensional torque.

[0021] Various multidimensional force sensor structures all include components such as an elastic cantilever beam, a substrate, a capacitor-to-digital converter (CDC) circuit, a processing module, and a circuit board.

[0022] The substrate acts as an outer shell to support the cantilever beam, protecting the internal electrodes and electronic components.

[0023] One end of the elastic cantilever beam 100 is fixed to the base, serving as a fixed support that does not produce axial, vertical displacement, or rotation. A free end in the middle generates forces parallel and perpendicular to the axial direction. A slot 101 is provided at the top of the free end. A shaft member is inserted into the slot at one end and fixed to a finger joint at the other end to transmit mechanical information. This mechanical information, through the deformation of the cantilever beam 100, causes the bending electrode to make contact with the lower electrode. The design of the cantilever beam 100 can be arbitrary, such as... Figures 1a to 1c The various styles shown. Figure 1a The 100-meter cantilever beam uses a cross arm, which has a simple structure and better force transmission performance in the cross arm direction, but there is a loss in other directions. Figure 1b The design of the cantilever beam 100 shown indicates that force is transmitted evenly in all directions. Figure 1c The design of the cantilever beam 100 shown achieves greater uniformity and is more complex than that in Figure 2. The design of the cantilever beam 100 varies, and this invention does not limit the specific design.

[0024] The circuit board uses a PCB-embedded substrate, with the capacitance-to-digital converter (CDC) circuit and processing module located on the back of the PCB. The CDC circuit, such as the DAI 7142 or ADI 7147, uses a Δ-Σ modulation method to convert the measured capacitance value into a digital value by repeatedly charging and discharging the capacitor under test and comparing it with a reference capacitance (see: US Patent Number: 5,134,401). This improves the measurement sensitivity to the 1ff level and achieves stray capacitance immunity. In particular, the chip design has multiple channels, allowing for separate coupling of corresponding electrodes to acquire capacitance. The processing module uses a microprocessor (CPU or MCU) as the computing unit. Coupled with the CDC circuit, the processing module outputs electrical signals characterizing force and torque based on the differences between the capacitances acquired by the CDC. The capacitance difference is calculated quickly using a differential algorithm.

[0025] Example 1

[0026] Figures 2a to 2eThis invention presents the first implementation structure of a multidimensional force sensor. In this structure, a cantilever beam 100 is mounted on a base 200, serving as the top surface suspended within the cavity of the base 200. Below the cantilever beam 100, at least three circumferentially distributed, common-ground flexible conductive strips 400 are arranged. These at least three conductive strips 400 can constitute the XYZ components. Considering symmetry, ease of calibration, and ease of arrangement, the embodiment uses four conductive strips 400 distributed at the top, bottom, left, right, and four corners. Figure 2d As shown. The conductive strip 400 can be implemented using a metal strip or by covering the FPC with strip-shaped copper electrodes, forming conductive properties and elastic deformation capability. All conductive strips 400 are arranged in a common ground and have the same potential. The cantilever beam 100 uses metal conductivity, and the conductive strips 400 are electrically connected to it, serving as a unified shield to improve the accuracy of mechanical measurements.

[0027] See Figure 2d Below each conductive strip 400, two lower electrodes 500 are positioned on either side of the central axis of the conductive strip 400. The lower electrodes 500 are insulated from each other. Each lower electrode 500 is located on the top surface of the circuit board 300, which serves as the supporting component for the lower electrode 500. The CDC and processing module are located on the bottom surface of the circuit board 300. The lower electrodes 500 are coupled through vias, facilitating wiring, enhancing system stability, and simplifying the structure. A potential difference is formed between the conductive strip 400 and the lower electrode 500.

[0028] In Example 1, each conductive strip 400 is connected at one end to form a whole, which can be integrally molded or cut to form a cross-shaped electrode. The cross-shaped connection is fixed relative to the lower electrode 500, and the fixation solves the problem of measurement reference change caused by the center deviation of the electrode strip. The fixing method can be to drill holes at the connection and fit it into the fixing member 301, which will generate friction. In order to avoid measurement interference caused by friction, the fixing method is preferably a locking fixing method, which is fastened to the center position of each lower electrode 500 on the circuit board 300 by the fixing member 301.

[0029] Each conductive strip 400 has its other end physically connected directly or indirectly to the cantilever beam 100 for fixation. The distance between the cantilever beam 100 and the lower electrode 500 is set such that the conductive strip 400 forms a bent electrode pre-pressed onto the lower electrode 500. The bent electrode forms the basis of the curved surface capacitance. The purpose of pre-pressing is to have a basic capacitance even without applied force. This basic capacitance has a certain size, which is larger than the capacitance generated by a small force or a small deviation of the electrode strip. This reduces the impact of a small force or a small deviation of the electrode strip on the test system, achieving less or even no calibration, and significantly reducing the difficulty of calibration.

[0030] refer to Figure 2eAn insulating layer is provided between the conductive strip 400 and the lower electrode 500. The insulating layer is not shown in the figure. It is formed by a coating process and covers the top surface of the lower electrode 500. The insulating film ensures the flatness of the top surface and has a thickness between 10 nanometers and 1 millimeter. Such a thin design will produce a huge capacitance change when in contact with the curved capacitor, so as to achieve high sensitivity of the sensor measurement.

[0031] Each conductive strip 400's projection relative to the lower electrode 500 at least synchronously covers a portion of the area of ​​each corresponding electrode below. The deformation of the cantilever beam 100 under external force causes the conductive strip 400 to change the indirect contact area of ​​the bent part on the lower electrode 500. The circumferential torsion under external force can create a difference in the projected area and / or distance of the conductive strip 400 relative to each corresponding electrode 500 below. The lower electrode 500 serves as a detection electrode, and the capacitance-to-digital conversion circuit is coupled to each lower electrode 500 to obtain the capacitance.

[0032] When the sensor is subjected to Z-axis pressure, the entire bent electrode is pressed down, and the capacitance of each lower electrode changes synchronously, thereby measuring the magnitude of the Z-axis or normal force. When subjected to Z-axis torsion, the capacitance difference between the two lower electrodes below each electrode is formed, thereby measuring the Z-axis torque. When subjected to X or Y-axis pressure, one end of the bent electrode is pressed down in the corresponding direction, while the opposite end is raised, such as... Figure 2d When the left side is pressed down, the right side tilts up, creating a capacitance difference between the two lower electrodes. This difference allows for the measurement of the force and torque in the X or Y direction. The combined force and torque in the X, Y, and Z directions yield the actual force direction and torque. During the bending deformation of the electrode under stress, the distance between the bending electrode and the lower electrode, the dielectric constant between them, and especially the indirect contact area all change. This results in a sensor sensitivity far exceeding that of the parallel plate capacitor, while also reducing the size of the electrode plate. Furthermore, the simple structure of the upper and lower electrodes facilitates compact design and sensor miniaturization, enabling the application of six-dimensional force measurement at small joints.

[0033] Example 2

[0034] Figures 3a to 3d The second implementation structure of the multidimensional force sensor of this utility model is presented. At least three circumferentially distributed flexible conductive strips 400 are provided below the cantilever beam 100. Similar to Embodiment 1, the conductive strips 400 are preferably arranged in four positions, distributed in the top, bottom, left, and right.

[0035] Two lower electrodes 500 are disposed below each conductive strip 400. The conductive strip 400 spans across the two corresponding lower electrodes 500. The lower electrodes 500 are insulated from each other and are also evenly distributed on the top surface of the circuit board 300. A potential difference is formed between the conductive strip 400 and the lower electrodes 500.

[0036] In Example 2, each conductive strip 400 is independently formed into separate parts. One end of each conductive strip 400 is directly or indirectly physically connected to the cantilever beam 100, using the direct or indirect physical connection method described below. The other end of each conductive strip 400 is directly or indirectly physically connected to the cantilever beam 100 or the lower electrode 500. The bottom of the conductive strip 400 is fixed relative to the lower electrode 500.

[0037] In the above, the scheme for fixing the conductive strip 400 relative to the cantilever beam 100 is as follows: Figure 3b , 3c As shown, the two ends of the conductive strip 400 are physically connected directly or indirectly to the cantilever beam 100, and the middle section is suspended below the cantilever beam 100 to form a U-shape. The bottom of the downward curve of the U-shape is fixed relative to the lower electrode 500. Alternatively, as... Figure 4a , 4b As shown, one end of the conductive strip 400 is physically connected directly or indirectly to the cantilever beam 100, and the other end is fixed as the bottom relative to the lower electrode 500 to form a lateral suspension wire.

[0038] The distance between the cantilever beam 100 and the lower electrode 500 is set such that each conductive strip 400400 of the aforementioned split forms a bent electrode pre-pressed onto the lower electrode 500.

[0039] The conductive strip 400 and the lower electrode 500 are also isolated by an insulating layer. The projection of each conductive strip 400 relative to the lower electrode 500 at least synchronously covers part of the area of ​​each corresponding electrode 500 below. The deformation of the cantilever beam 100 under the action of external force causes the conductive strip 400 to change the indirect contact area of ​​the bent part on the lower electrode 500. The circumferential torsion under the action of external force can form a difference in the projected area and / or distance of the conductive strip 400 relative to each corresponding electrode 500 below. In this scheme, the lower electrode 500 serves as the detection electrode, and the capacitance-to-digital conversion circuit is coupled to each lower electrode 500 to obtain the capacitance.

[0040] When subjected to Z-axis pressure, the split bending electrodes press down synchronously, and the capacitance of each lower electrode changes synchronously, allowing the measurement of the magnitude of the Z-axis or normal force. When subjected to Z-axis torsion, the electrode band twists, changing the projection and distance of the two lower electrodes spanning below, creating a capacitance difference between the two lower electrodes, allowing the measurement of the Z-axis torque. Similarly, when subjected to X or Y-axis pressure, one end tilts up while the other end is pressed down, creating a capacitance difference between the left and right lower electrodes, allowing the measurement of the X or Y-axis force and torque. The curved surface capacitor between the bending electrode and the lower electrode achieves advantages such as high sensitivity, compactness, and small size. Furthermore, compared to the integral conductive strip scheme in Example 1, the split conductive strip design has superior mechanical properties and better sensor sensitivity.

[0041] Example 3

[0042] Figures 5a to 5cThe third implementation structure of the multidimensional force sensor of this utility model is given. Embodiments 1 and 2 use an upper conductive strip 400 corresponding to two lower electrodes 500, while embodiment 3 uses a lower electrode 500 corresponding to two upper conductive strips 400 to form a six-dimensional force detection.

[0043] See Figures 5a to 5c Below the cantilever beam 100, at least three pairs of circumferentially distributed flexible conductive strips 400 are provided. Each pair of conductive strips 400 has a corresponding lower electrode 500 below it. All lower electrodes 500 share a common ground, and can be integrated as a single unit. Figure 5c As shown, it can also be adopted as four separate units, that is, they are not connected to each other and share a common ground through PCB traces. Each pair of conductive strips 400 is distributed on both sides of the central axis of the corresponding lower electrode 500. The conductive strips 400 are insulated from each other, and the conductive strips 400 and the lower electrode 500 form a potential difference. Similar to embodiment 2, each conductive strip 400 forms a separate unit independently. Each conductive strip 400 is directly or indirectly physically connected to the cantilever beam 100, and the other end is directly or indirectly physically connected to the cantilever beam 100 or the lower electrode 500. The bottom of the conductive strip 400 is fixed relative to the lower electrode 500. The distance between the cantilever beam 100 and the lower electrode 500 is set so that the conductive strip 400 forms a bent electrode pre-pressed on the lower electrode 500. An insulating layer is also provided between the conductive strip 400 and the lower electrode 500. The projection of the lower electrode 500 relative to the conductive strip 400 at least synchronously covers a portion of the area of ​​each corresponding conductive strip 400 above it. The deformation of the cantilever beam 100 under external force causes the conductive strip 400 to change the indirect contact area of ​​its bent portion on the lower electrode 500. The circumferential torsion under external force can create differences in the projected area and / or distance of the lower electrode 500 relative to each corresponding conductive strip 400 above it. In embodiment 3, the conductive strip serves as the detection electrode, and the capacitance-to-digital conversion circuit is coupled to each conductive strip to obtain the capacitance.

[0044] When subjected to Z-axis pressure, the split bending electrodes press down synchronously, and the capacitance of each conductive strip changes synchronously, allowing the measurement of the magnitude of the Z-axis or normal force. When subjected to Z-axis torsion, the electrode strips twist, and the capacitance between the two conductive strips corresponding to each lower electrode forms a difference, allowing the measurement of the Z-axis torque. When subjected to X or Y-axis pressure, one end also tilts up while the other end is pressed down, allowing the measurement of the X or Y-axis force and torque.

[0045] Example 4

[0046] In Example 3 Figure 5c On the basis of, such as Figure 6aThe opposing ends of the conductive strips can be connected by an insulating component to form the whole of Embodiment 1. In this case, at least three pairs of flexible conductive strips 400 are arranged circumferentially below the cantilever beam 100. The conductive strips 400 are insulated from each other. A lower electrode 500 is arranged below each pair of conductive strips 400. All lower electrodes 500 share a common ground. Similar to Embodiment 3, the lower electrode 500 can be integral or separate. Figure 6a The design is integrated into one piece. Each pair of conductive strips 400 is distributed on both sides of the central axis of the corresponding lower electrode 500, and the conductive strips 400 and the lower electrode 500 form a potential difference.

[0047] Each conductive strip 400 is connected at one end by an insulating component 401 to form a whole, and the connection point is fixed relative to the lower electrode 500. The other end is physically connected directly or indirectly to the cantilever beam 100. The distance between the cantilever beam 100 and the lower electrode 500 is set such that the conductive strip 400 forms a curved electrode pre-pressed on the lower electrode 500, serving as the basis for the curved capacitor.

[0048] An insulating layer is provided between the conductive strip 400 and the lower electrode 500. The projection of the lower electrode 500 relative to the conductive strip 400 at least synchronously covers a portion of the area of ​​each corresponding conductive strip 400 above it. The deformation of the cantilever beam 100 under external force causes the conductive strip 400 to change the indirect contact area of ​​its bent portion on the lower electrode 500. Furthermore, the circumferential torsion under external force can create differences in the projected area and / or distance of the lower electrode 500 relative to each corresponding conductive strip 400 above it. The conductive strip serves as the detection electrode, and the capacitance-to-digital conversion circuit is coupled to each conductive strip to obtain the capacitance. Similar to Embodiment 3, this structure can measure six-dimensional force.

[0049] In the above embodiments, the maximum deformation of the bending electrode preload is set to be greater than the maximum stroke of the cantilever beam relative to the lower electrode direction. This ensures that whether the sensor is pressed or pulled, or whether one end is tilted up and the other is pressed down, the conductive strip 400 at the corresponding location will not completely leave the insulating layer on the top surface of the lower electrode 500. There will always be an indirect contact area at the corresponding location to form a capacitance measurement value, ensuring the calculation of capacitance differences at various locations and improving system stability.

[0050] In the above embodiments, the end of the conductive strip 400 can be directly fixed to the laterally extending wing of the cantilever beam 100 by adhesive bonding, spot welding, or friction welding, achieving a direct physical connection. This solution has the advantage of simple structure, but it slightly reduces the deformation of the bent electrode. Preferably, as... Figure 3b , 4b5b also includes a rigid body 102 and a connector. The rigid body 102 can be a rigid disk, suspended below the cantilever beam 100, with a gap between its top surface and the bottom surface of the cantilever beam 100. It is fixed relative to the geometric center of the cantilever beam 100 by the connector. The end of the conductive strip 400 is connected to the rigid body 102, achieving an indirect physical connection. This scheme amplifies the torque by using a rigid body, and unlike direct physical connection schemes, it does not absorb some of the deformation of the bending electrode, thus better transmitting the force. Furthermore, the thickness of the bending electrode can be made thinner, which is beneficial for volume reduction.

[0051] In the above embodiments, the lower electrode 500 can be a planar electrode with the shape of... Figure 7a The sector shown or Figure 7b The strip shown can also be a curved electrode, such as the lower electrode 500. Figure 8a , 8b As shown.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A multidimensional force sensor, characterized in that: Includes a flexible cantilever beam, a base, a capacitor-to-digital converter circuit, and a processing module; The cantilever beam is installed on the base. At least three circumferentially distributed flexible conductive strips are arranged below the cantilever beam. Each conductive strip has two lower electrodes arranged on the left and right sides of the central axis of the conductive strip. The lower electrodes are insulated from each other, and a potential difference is formed between the conductive strip and the lower electrodes. Each conductive strip is connected at one end to form a whole, and the connection point is fixed relative to the lower electrode. The other end is directly or indirectly physically connected to the cantilever beam for fixation. The distance between the cantilever beam and the lower electrode is set so that the conductive strip forms a bent electrode pre-pressed on the lower electrode. An insulating layer is provided between the conductive strip and the lower electrode. The projection of each conductive strip relative to the lower electrode at least synchronously covers part of the area of ​​each corresponding electrode below. The deformation of the cantilever beam under the action of external force causes the conductive strip to change the indirect contact area of ​​the bent part on the lower electrode. The circumferential torsion under the action of external force can form the difference in the projected area and / or distance of the conductive strip relative to each corresponding electrode below. The capacitance-to-digital conversion circuit is coupled to each lower electrode to obtain the capacitance; The processing module is coupled to a capacitor-to-digital converter circuit, which is used to output electrical signals representing force and torque based on the capacitor.

2. A multidimensional force sensor, characterized in that: Includes a flexible cantilever beam, a base, a capacitor-to-digital converter circuit, and a processing module; The cantilever beam is installed on the base. At least three circumferentially distributed flexible conductive strips are arranged below the cantilever beam. Two lower electrodes are arranged below each conductive strip. The conductive strips span over the two lower electrodes. The lower electrodes are insulated from each other. A potential difference is formed between the conductive strips and the lower electrodes. Each conductive strip is independently formed into a separate body. One end of each conductive strip is directly or indirectly physically connected to the cantilever beam, and the other end is directly or indirectly physically connected to the cantilever beam or the lower electrode. The bottom of the conductive strip is fixed relative to the lower electrode. The distance between the cantilever beam and the lower electrode is set such that the conductive strip forms a bent electrode pre-pressed on the lower electrode. An insulating layer is provided between the conductive strip and the lower electrode. The projection of each conductive strip relative to the lower electrode at least synchronously covers part of the area of ​​each corresponding electrode below. The deformation of the cantilever beam under the action of external force causes the conductive strip to change the indirect contact area of ​​the bent part on the lower electrode. The circumferential torsion under the action of external force can form the difference in the projected area and / or distance of the conductive strip relative to each corresponding electrode below. The capacitance-to-digital conversion circuit is coupled to each lower electrode to obtain the capacitance; The processing module is coupled to a capacitor-to-digital converter circuit, which is used to output electrical signals representing force and torque based on the capacitor.

3. The multidimensional force sensor according to claim 2, characterized in that: The two ends of the conductive strip are physically connected directly or indirectly to the cantilever beam, the middle section is suspended below the cantilever beam, and the bottom of the downward-curving valley is fixed relative to the lower electrode.

4. The multidimensional force sensor according to claim 2, characterized in that: One end of the conductive strip is physically connected directly or indirectly to the cantilever beam, while the other end is fixed as the bottom electrode relative to the lower electrode.

5. The multidimensional force sensor according to claim 1 or 2, characterized in that: The conductive strip and the cantilever beam are grounded together.

6. A multidimensional force sensor, characterized in that: Includes a flexible cantilever beam, a base, a capacitor-to-digital converter circuit, and a processing module; The cantilever beam is installed on the base. At least three pairs of flexible conductive strips are arranged circumferentially below the cantilever beam. The conductive strips are insulated from each other. A lower electrode is arranged below each pair of conductive strips. All lower electrodes are grounded. Each pair of conductive strips is distributed on both sides of the central axis of the corresponding lower electrode. The conductive strips and the lower electrode form a potential difference. Each conductive strip is independently formed into a separate body. One end of each conductive strip is directly or indirectly physically connected to the cantilever beam, and the other end is directly or indirectly physically connected to the cantilever beam or the lower electrode. The bottom of the conductive strip is fixed relative to the lower electrode. The distance between the cantilever beam and the lower electrode is set such that the conductive strip forms a bent electrode pre-pressed on the lower electrode. An insulating layer is provided between the conductive strip and the lower electrode. The projection of the lower electrode relative to the conductive strip at least synchronously covers part of the area of ​​each corresponding conductive strip above. The deformation of the cantilever beam under the action of external force causes the conductive strip to change the indirect contact area of ​​the bent part on the lower electrode. The circumferential torsion under the action of external force can form the difference in the projected area and / or distance of the lower electrode relative to each corresponding conductive strip above. The capacitance-to-digital conversion circuit couples each conductive strip to obtain the capacitance; The processing module is coupled to a capacitor-to-digital converter circuit, which is used to output electrical signals representing force and torque based on the capacitor.

7. A multidimensional force sensor, characterized in that: Includes a flexible cantilever beam, a base, a capacitor-to-digital converter circuit, and a processing module; The cantilever beam is installed on the base. At least three pairs of flexible conductive strips are arranged circumferentially below the cantilever beam. The conductive strips are insulated from each other. A lower electrode is arranged below each pair of conductive strips. All lower electrodes are grounded. Each pair of conductive strips is distributed on both sides of the central axis of the corresponding lower electrode. The conductive strips and the lower electrode form a potential difference. Each conductive strip is connected at one end by an insulating component, with the connection point fixed relative to the lower electrode. The other end is physically connected directly or indirectly to the cantilever beam. The distance between the cantilever beam and the lower electrode is set such that the conductive strip forms a bent electrode pre-pressed onto the lower electrode. An insulating layer is provided between the conductive strip and the lower electrode. The projection of the lower electrode relative to the conductive strip at least synchronously covers part of the area of ​​each corresponding conductive strip above. The deformation of the cantilever beam under the action of external force causes the conductive strip to change the indirect contact area of ​​the bent part on the lower electrode. The circumferential torsion under the action of external force can form the difference in the projected area and / or distance of the lower electrode relative to each corresponding conductive strip above. The capacitance-to-digital conversion circuit couples each conductive strip to obtain the capacitance; The processing module is coupled to a capacitor-to-digital converter circuit, which is used to output electrical signals representing force and torque based on the capacitor.

8. The multidimensional force sensor according to any one of claims 1-4, 6, and 7, characterized in that: The maximum deformation of the bending electrode under preload is greater than the maximum stroke of the cantilever beam relative to the lower electrode.

9. The multidimensional force sensor according to any one of claims 1-4, 6, and 7, characterized in that: The conductive strip is connected to the cantilever beam at one end.

10. The multidimensional force sensor according to any one of claims 1-4, 6, and 7, characterized in that: It also includes a rigid body and a connector. The rigid body is suspended below the cantilever beam, with a gap between its top surface and the cantilever beam. It is fixed relative to the geometric center of the cantilever beam by the connector, and the end of the conductive strip is connected to the rigid body.

11. The multidimensional force sensor according to any one of claims 1-4, 6, and 7, characterized in that: It also includes a circuit board, with each lower electrode located on the top surface of the circuit board, which serves as the supporting component for the lower electrode.

12. The multidimensional force sensor according to claim 11, characterized in that: The capacitor-to-digital conversion circuit and processing module are located on the bottom of the circuit board.

13. The multidimensional force sensor according to any one of claims 1-4, 6, and 7, characterized in that: The lower electrode can be a planar electrode or a curved electrode.

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