Capacitive force sensor, method of measuring external force received by detection device

Abstract

The embodiment of the application provides a capacitive force sensor and a measurement method for detecting external force borne by equipment by using the capacitive force sensor, relates to the technical field of force sensors, and is mainly used for providing a capacitive force sensor capable of improving measurement sensitivity. The capacitive force sensor comprises: a first electrode plate and a second electrode plate opposite to each other, one of the first electrode plate and the second electrode plate is fixedly connected with an elastic body, the elastic body drives the electrode plate fixedly connected with the elastic body to move horizontally and rotate relative to the other electrode plate; and in addition, a plurality of first electrodes and a plurality of second electrodes are arranged alternately on the first electrode plate, and a plurality of third electrodes for forming capacitors with the plurality of first electrodes and the plurality of second electrodes are arranged on the second electrode plate. The capacitor provided in the application is not only an area change type capacitor, but also a distance change type capacitor, a plurality of variable capacitors are arranged in parallel, so that the area change amount is improved, and the sensitivity is improved.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of force sensor, and particularly relates to a capacitive force sensor based on capacitance change and capable of measuring multi-dimensional force, and a measurement method for detecting external force borne by equipment by using the capacitive force sensor. BACKGROUND

[0002] The multi-dimensional force sensor can realize measurement of space force and torque, and is widely applied in the fields of robot, aerospace, mechanical processing, automobile manufacturing and multi-degree-of-freedom precise assembly. The multi-dimensional force sensor based on capacitance change is widely used because of the characteristics of not being easily affected by temperature, high precision and resolution, and belonging to non-contact measurement.

[0003] The multi-dimensional force sensor based on capacitance change generally has three modes, namely area change mode, interval change mode and dielectric constant change mode. At present, the multi-dimensional force sensor based on area change and interval change principle is commonly used.

[0004] Figure 1 A principle structure diagram of the capacitive multi-dimensional force sensor is shown, and the specific working principle comprises the following steps: when external force acts on the capacitive multi-dimensional force sensor, the deformation of the elastic body 03 drives the displacement of the movable electrode plate 02, the displacement causes at least one parameter of the effective area S and the interval d between the fixed electrode plate 01 and the movable electrode plate 02 to change, when at least one parameter of the effective area S and the interval d changes, the capacitance change is caused, and the capacitance change amount is measured to represent the size of the external force borne by the multi-dimensional force sensor.

[0005] In some cases, the multi-dimensional force sensor is affected by external force to cause the deformation displacement amount of the elastic body 03 to be relatively small, and at least the following phenomena may occur: 1) the effective area S changes slightly, the capacitance change is very small, and the sensitivity of the multi-dimensional force sensor is low; 2) when the initial interval between the movable electrode plate 02 and the fixed electrode plate 01 is large, the interval d changes slightly, the capacitance change is small, and the sensitivity of the sensor is also low.

[0006] In order to improve the sensitivity of the multi-dimensional force sensor, the effective area between the fixed electrode plate 01 and the movable electrode plate 02 can be increased to improve the area change under the condition of slight displacement, which will lead to the increase of the overall volume of the multi-dimensional force sensor; or the initial interval between the fixed electrode plate 01 and the movable electrode plate 02 can be reduced (for example, the initial interval is reduced to 100-200 μm) to improve the capacitance change under the condition of slight interval change, but this may cause the processing and installation difficulty of the sensor to increase, and challenge the manufacturing process.

[0007] Based on the technical problems existing in the multi-dimensional force sensor, a multi-dimensional force sensor capable of improving measurement sensitivity and use performance is needed. SUMMARY

[0008] The application provides a capacitive force sensor and a measurement method for detecting external force of equipment by using the capacitive force sensor. The main purpose is to provide a capacitive force sensor capable of improving measurement sensitivity without increasing the volume of the sensor and without increasing the process difficulty.

[0009] To achieve the above purpose, the embodiments of the application adopt the following technical solutions:

[0010] In a first aspect, the application provides a capacitive force sensor which can be applied to robots, aerospace, mechanical processing, automobile manufacturing and other equipment to measure the spatial external force of the equipment.

[0011] The capacitive force sensor comprises a first electrode plate, a second electrode plate, an elastic body and at least one electrode group. The second electrode plate is arranged opposite to the first electrode plate, and the first electrode plate and the second electrode plate have a spacing therebetween. One of the first electrode plate and the second electrode plate is a fixed electrode plate, and the other is a movable electrode plate. The elastic body is fixedly connected to the movable electrode plate. The elastic body can drive the movable electrode plate to move relative to the fixed electrode plate along a direction parallel to the fixed electrode plate and a direction perpendicular to the fixed electrode plate, and can drive the movable electrode plate to rotate relative to the fixed electrode plate along an axis parallel to the fixed electrode plate and an axis perpendicular to the fixed electrode plate. That is, one of the first electrode plate and the second electrode plate can move relative to the other. In addition, any electrode group comprises a plurality of first electrodes electrically connected to each other, a plurality of second electrodes electrically connected to each other and a plurality of third electrodes electrically connected to each other. The plurality of first electrodes and the plurality of second electrodes are arranged on a surface of the first electrode plate opposite to the second electrode plate, and the plurality of first electrodes and the plurality of second electrodes are arranged alternately. The plurality of third electrodes are arranged on a surface of the second electrode plate opposite to the first electrode plate, and the first electrodes, the third electrodes and the second electrodes are arranged in a staggered manner. Any third electrode and its adjacent first electrode and second electrode form a coupling structure, and any first electrode or any second electrode belongs to an independent coupling structure. When the movable electrode plate moves relative to the fixed electrode plate, the plurality of first electrodes and the plurality of third electrodes form a first capacitor, and the plurality of second electrodes and the plurality of third electrodes form a second capacitor.

[0012] Based on the above description of the capacitive force sensor structure of the present application, it can be seen that the capacitive force sensor is a kind of capacitive grid type grid structure. And the movable electrode plate can not only move along the direction parallel to the fixed electrode plate and the direction perpendicular to the fixed electrode plate, but also rotate along the axis parallel to the fixed electrode plate and the axis perpendicular to the fixed electrode plate under the driving of the elastic body. That is, the force sensor not only belongs to the area change type sensor, but also belongs to the pitch change type sensor.

[0013] The force sensor has a small displacement, and the capacitance change of the area change type sensor is significantly higher than that of the existing ordinary flat plate type sensor structure. Specifically, for example, when the movable electrode plate moves ΔX relative to the fixed electrode plate along the direction parallel to the fixed electrode plate, in the prior art, the area change is H×ΔX (H is the size of the movable electrode plate perpendicular to the moving direction of the movable electrode plate), however, in the present application, since the first electrode and the second electrode on the first electrode plate are both multiple, and the third electrode on the second electrode plate is also multiple, in this way, when the movable electrode plate moves ΔX relative to the fixed electrode plate along the direction parallel to the fixed electrode plate, the area change of the present application is N×H×ΔX (N is the smaller number of the first electrode, the second electrode and the third electrode), thus, from N×H×ΔX compared with H×ΔX, it can be seen that the present application can significantly increase the area change, and then the capacitance change will be significantly improved, and finally the sensitivity will be effectively improved.

[0014] In addition, in the present application, multiple first electrodes, multiple second electrodes and multiple third electrodes are arranged on the first electrode plate and the second electrode plate to form a first capacitor with the multiple first electrodes and the multiple third electrodes, and a second capacitor with the multiple second electrodes and the multiple third electrodes, so as to increase the area change and improve the capacitance change. It can be understood that one large size electrode in the prior art can be divided into multiple electrodes, so that the area change and the capacitance change are increased without increasing the size of the entire sensor; in addition, the distance between the two electrode plates is not reduced to improve the sensitivity. Therefore, the capacitive force sensor provided in the present application can improve the measurement sensitivity without increasing the size of the sensor and improving the process difficulty.

[0015] In a possible implementation manner of the first aspect, the width of any first electrode and any second electrode along the arrangement direction of the multiple first electrodes and the multiple second electrodes is W1, the width of each adjacent first electrode and second electrode is W2, and the width of any third electrode is W, and the width between each adjacent two third electrodes is W, wherein W=W1+W2.

[0016] When the first electrode, the second electrode and the third electrode satisfy the above size limitation, the capacitance value of the first capacitor and the capacitance value of the second capacitor change linearly, so that the model complexity can be simplified and the solving difficulty can be reduced.

[0017] The width size in the above implementation manner can be a linear width size or an angular width size.

[0018] In a possible implementation of the first aspect, the at least one electrode group includes a first electrode group; in the first electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged in a straight line along a first direction parallel to the first electrode plate, and the plurality of third electrodes are arranged in the same direction as the plurality of first electrodes and the plurality of second electrodes.

[0019] If the plurality of first electrodes and the plurality of second electrodes in the first electrode group are arranged in a straight line along the first direction, the first capacitor and the second capacitor formed thereby can be used to measure the force Fx of the sensor in the X direction, where the X direction is a direction parallel to the first direction, or when a plurality of electrode groups along the first direction are provided, the My around the Y direction and the force Fz along the Z direction can also be measured, where the Y direction and the Z direction are both directions perpendicular to the X direction.

[0020] In a possible implementation of the first aspect, the at least one electrode group includes a first electrode group; in the first electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged in an arc along a circumferential direction of the first electrode plate, and the plurality of third electrodes are arranged in the same direction as the plurality of first electrodes and the plurality of second electrodes.

[0021] If the plurality of first electrodes and the plurality of second electrodes in the first electrode group are arranged in an arc along the circumferential direction of the first electrode plate, the first capacitor and the second capacitor formed thereby can be used to measure the force Fz of the sensor along the Z direction. Further, when a plurality of electrode groups arranged in an arc are provided, the torque Mz around the Z direction axis can also be measured, and the Mx and the My can also be measured. Here, the Z direction is a direction perpendicular to the first electrode plate, the X direction and the Y direction are both directions parallel to the first electrode plate, and the X direction and the Y direction are perpendicular to each other.

[0022] In a possible implementation of the first aspect, the orthographic projection of the first electrode and the second electrode on the second electrode plate covers the third electrode in a direction perpendicular to the arrangement direction of the plurality of first electrodes and the plurality of second electrodes.

[0023] That is, the size of the first electrode and the second electrode is greater than the size of the third electrode in the direction perpendicular to the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, so that when the first electrode plate moves relative to the second electrode plate in the first direction, even if there is a small displacement in the second direction (that is, the direction perpendicular to the arrangement direction of the plurality of first electrodes and the plurality of second electrodes), the change in the effective area between the first electrode plate and the second electrode plate caused by the small displacement in the second direction is variable, so that the design can guarantee the accuracy of the measurement.

[0024] In a possible implementation of the first aspect, a projection of the third electrode on the first electrode plate in the direction perpendicular to the arrangement direction of the plurality of first electrodes and the plurality of second electrodes covers the first electrode and the second electrode.

[0025] It can be understood that, in the direction perpendicular to the arrangement direction of the plurality of first electrodes and the pluralityity of second electrodes, the size of the first electrode and the size of the third electrode can not be equal, and the size of the second electrode and the size of the third electrode are not equal.

[0026] In a possible implementation of the first aspect, the at least one electrode group further includes a second electrode group; the plurality of first electrodes and the plurality of second electrodes in the first electrode group and the plurality of first electrodes and the plurality of second electrodes in the second electrode group are arranged on both sides of the center of the first electrode plate; in the second electrode group, the width of any first electrode and any second electrode in the arrangement direction of the plurality of first electrodes and the plurality of second electrodes is W1, the width of each adjacent first electrode and second electrode is W2, and the width of any third electrode is W, and the width between each adjacent two third electrodes is W, wherein W=W1+W2.

[0027] That is, the sensor further includes a second electrode group in addition to the first electrode group, and the first electrode group and the second electrode group are arranged on both sides of the center of the first electrode plate and the second electrode plate, so that the area change can be further increased, the capacitance change can be further improved, and the sensitivity can be further improved.

[0028] Similarly, in the second electrode group described above, the width can be a linear width or an angular width.

[0029] In a possible implementation manner of the first aspect, in the first electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with the center line of the first electrode; in the second electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with the center line of the first electrode; wherein the center line of the first electrode is a center line of the first electrode along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes.

[0030] The arrangement manner of the first electrode, the second electrode and the third electrode provided in the present application can be understood as follows: along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the first electrode has a center line, the second electrode also has a center line, and the opposite two side edges of the third electrode coincide with the center line of the first electrode and the center line of the second electrode respectively. That is to say, in any coupling structure, the third electrode is symmetrically arranged between the first electrode and the second electrode, and when the capacitance values of the first capacitor and the second capacitor are differentiated, the size change of the differential signal is twice the size change of the capacitance value of the first capacitor or the capacitance value of the second capacitor, so that the capacitance change size can be further improved.

[0031] In a possible implementation manner of the first aspect, the capacitive force sensor further includes a processor; the processor obtains C1 - according to a difference formula C1 - , obtains C2 - according to a difference formula C2 - ; and obtains C1 + according to a sum formula C1 + , obtains C2 + according to a sum formula C2 + ; the processor further calculates an external force F borne by the capacitive force sensor according to C1 - , C2 - , C1 + and C2 + ; wherein C1 is a capacitance value output by a first capacitor in the first electrode group; C2 is a capacitance value output by a second capacitor in the first electrode group; C3 is a capacitance value output by a first capacitor in the second electrode group; and C4 is a capacitance value output by a second capacitor in the second electrode group.

[0032] In a possible implementation of the first aspect, in the first electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the first electrode; in the second electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of a gap between the first electrode and the second electrode; wherein the center line of the first electrode is a center line of the first electrode along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes.

[0033] In this implementation, the arrangement of the first electrode, the second electrode, and the third electrode in the first electrode group is different from the arrangement of the first electrode, the second electrode, and the third electrode in the second electrode group.

[0034] In a possible implementation of the first aspect, the capacitive force sensor further includes a processor; the processor obtains C1 - according to a difference formula C1 - , and obtains C2 - according to a difference formula C2 - ; and the processor calculates an external force F borne by the capacitive force sensor according to C1 - and C2 - ; wherein C1 is a capacitance value output by a first capacitor in the first electrode group; C2 is a capacitance value output by a second capacitor in the first electrode group; C3 is a capacitance value output by a first capacitor in the second electrode group; and C4 is a capacitance value output by a second capacitor in the second electrode group.

[0035] Since the arrangement of the first electrode, the second electrode, and the third electrode in the first electrode group is different from the arrangement of the first electrode, the second electrode, and the third electrode in the second electrode group, only a difference processing method is used when calculating the external force borne by the sensor, which can reduce the calculation complexity and improve the signal processing rate.

[0036] In a possible implementation of the first aspect, the capacitive force sensor further comprises a third electrode plate, the third electrode plate is arranged on a side of the second electrode plate facing away from the first electrode plate; the at least one electrode group further comprises a third electrode group; in the third electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged on a surface of the third electrode plate opposite to the second electrode plate, and the plurality of third electrodes are arranged on a surface of the second electrode plate opposite to the third electrode plate; and the third electrode group and the first electrode group are symmetrically arranged about the second electrode plate. That is, in the third electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the third electrode plate coincides with a center line of the first electrode.

[0037] In this way, the capacitive force sensor provided in the embodiment comprises the first electrode plate, the second electrode plate and the third electrode plate stacked in sequence, and the third electrode is arranged on the surface of the second electrode plate opposite to the first electrode plate and the third electrode plate. In this way, the sensitivity of the area change type capacitor can be doubled, and the sensitivity of the pitch change type capacitor can be increased.

[0038] In a possible implementation of the first aspect, the capacitive force sensor further comprises a processor; the processor obtains C1 U- according to a difference formula C1 U- , obtains C1 D- according to a difference formula C1 D- , and obtains C1 U+ according to a sum formula C1 U+ , obtains C1 D+ according to a sum formula C1 D+ ; and the processor further calculates an external force F borne by the capacitive force sensor according to C1 - = C1 U- + C1 D- and C1 + = C1 U+ - C1 D+ ; wherein C1 is a capacitance value output by a first capacitor in the first electrode group; C2 is a capacitance value output by a second capacitor in the first electrode group; C5 is a capacitance value output by a first capacitor in the third electrode group; and C6 is a capacitance value output by a second capacitor in the third electrode group.

[0039] When the force sensor comprises a third electrode plate in addition to the first electrode plate and the second electrode plate, and the third electrode is symmetrically arranged between the first electrode and the second electrode, the size of the space external force can be calculated by using the difference signal processing and the sum signal processing method.

[0040] In a possible implementation manner of the first aspect, the capacitive force sensor further comprises a third electrode plate, the third electrode plate is arranged on a side of the second electrode plate which is away from the first electrode plate; the at least one electrode group further comprises a third electrode group; in the third electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged on a surface of the third electrode plate which is opposite to the second electrode plate, and the plurality of third electrodes are arranged on a surface of the second electrode plate which is opposite to the third electrode plate; and the third electrode group and the first electrode group are symmetrically arranged about the second electrode plate, that is, in the third electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of a gap between the first electrode and the second electrode.

[0041] Similarly, by adding the third electrode plate, the sensitivity of the area change type capacitor can be further doubled, and the sensitivity of the spacing change type capacitor can also be increased.

[0042] In a possible implementation manner of the first aspect, the capacitive force sensor further comprises a processor; the processor obtains C1 U- according to a difference formula C1 U- , obtains C1 D- according to a difference formula C1 D- ; and the processor further calculates an external force F borne by the capacitive force sensor according to C1 - = C1 U- + C1 D- ; wherein C1 is a capacitance value output by a first capacitor in the first electrode group; C2 is a capacitance value output by a second capacitor in the first electrode group; C5 is a capacitance value output by a first capacitor in the third electrode group; and C6 is a capacitance value output by a second capacitor in the third electrode group.

[0043] In the implementation manner, since the side edge of the third electrode coincides with the center line of the gap between the first electrode and the second electrode, the spatial external force size can be calculated by using a difference signal processing manner, and the measurement sensitivity can be improved by using the difference for not only the area change type capacitor but also the spacing change type capacitor.

[0044] In a possible implementation manner of the first aspect, the at least one electrode group further comprises a fifth electrode group; in the fifth electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged on a surface of the first electrode plate which is opposite to the second electrode plate along a second direction, and the plurality of third electrodes are arranged on a surface of the second electrode plate which is opposite to the third electrode plate; and the second direction is perpendicular to the first direction.

[0045] In this way, forces in the first and second perpendicular directions can be measured. For example, not only the force Fx in the X direction, the torque My around the Y direction axis, and the force Fz in the Z direction, but also the force Fy in the Y direction, the torque Mx around the X direction axis, and the force Fz in the Z direction can be measured.

[0046] In a possible implementation of the first aspect, eight groups of electrode groups are arranged on the opposite first and second electrode plates, and the eight groups of electrode groups are arranged at intervals along the circumferences of the first and second electrode plates.

[0047] For example, two of the eight groups of electrode groups are arranged in the X direction, two are arranged in the Y direction, two are arranged in the +45° direction, and the remaining two are arranged in the -45° direction. In this way, the sensor formed can be referred to as a six-dimensional force sensor.

[0048] In a possible implementation of the first aspect, the capacitive force sensor further includes a main body and a force receiving plate, the main body has a receiving cavity formed therein; an elastic body is arranged in the receiving cavity, the elastic body includes a connecting portion and a plurality of elastic arms arranged at intervals along the circumference of the connecting portion, and an end of each elastic arm away from the connecting portion is fixedly connected to the main body; the first and second electrode plates are both arranged in the receiving cavity, the second electrode plate is arranged opposite the elastic body and is fixedly connected to the connecting portion, and the first electrode plate is arranged on a side of the second electrode plate away from the elastic body and is fixedly connected to the main body; and the force receiving plate is arranged outside the receiving cavity and is fixedly connected to the second electrode plate.

[0049] The capacitive force sensor provided in this embodiment, when in use, when an external force acts on the force receiving plate, the elastic arms will move under the drive of the force receiving plate, thereby driving the second electrode plate to move relative to the first electrode plate, so that the size of the external force is measured through the electrode groups arranged on the first and second electrode plates.

[0050] In a possible implementation of the first aspect, the capacitive force sensor further includes a circuit board, the circuit board is arranged in the receiving cavity and is arranged opposite the second electrode plate on both sides of the elastic body. The processor for processing the capacitance value can be located on the circuit board.

[0051] In a possible implementation of the first aspect, the capacitive force sensor further includes a base, and the base, the main body, and the force receiving plate can enclose a sealed receiving cavity, and the first and second electrode plates and the circuit board can be arranged in the sealed receiving cavity to protect these electronic components.

[0052] In a second aspect, the application provides a measurement method for detecting an external force borne by a detection device using a capacitive force sensor, the capacitive force sensor being installed on the detection device, the capacitive force sensor comprising a first electrode plate, a second electrode plate, an elastic body and at least one electrode group; the second electrode plate is arranged opposite the first electrode plate, and the first electrode plate and the second electrode plate have a spacing therebetween, one of the first electrode plate and the second electrode plate is a fixed electrode plate, and the other is a movable electrode plate; the elastic body is fixedly connected to the movable electrode plate, and the elastic body can drive the movable electrode plate to move relative to the fixed electrode plate in a direction parallel to the fixed electrode plate and in a direction perpendicular to the fixed electrode plate, and can drive the movable electrode plate to rotate relative to the fixed electrode plate along an axis parallel to the fixed electrode plate and an axis perpendicular to the fixed electrode plate; in addition, any electrode group comprises: a plurality of first electrodes electrically connected to each other, a plurality of second electrodes electrically connected to each other, and a plurality of third electrodes electrically connected to each other, the plurality of first electrodes and the plurality of second electrodes are arranged on a surface of the first electrode plate opposite the second electrode plate, and the plurality of first electrodes and the plurality of second electrodes are arranged alternately in sequence, the plurality of third electrodes are arranged on a surface of the second electrode plate opposite the first electrode plate, and the first electrodes, the third electrodes and the second electrodes are arranged in a staggered manner, any third electrode and its adjacent first electrode and second electrode form a coupling structure, and any first electrode or any second electrode belongs to an independent coupling structure; when the movable electrode plate moves relative to the fixed electrode plate, the plurality of first electrodes and the plurality of third electrodes form a first capacitor, and the plurality of second electrodes and the plurality of third electrodes form a second capacitor.

[0053] The measurement method provided by the embodiment comprises: collecting a capacitance value of the first capacitor, and collecting a capacitance value of the second capacitor; and measuring the external force F borne by the detection device according to the capacitance value of the first capacitor and the capacitance value of the second capacitor.

[0054] In the measurement method provided by the embodiment, the capacitive force sensor provided by the above embodiment is used. Since the plurality of first electrodes and the plurality of second electrodes arranged on the first electrode plate and the plurality of third electrodes arranged on the second electrode plate are included in the sensor, the area change can be obviously increased compared with the sensor of the prior art, the capacitance change can be obviously improved, and the measurement sensitivity can be effectively improved.

[0055] In a possible implementation of the second aspect, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the width of any first electrode and any second electrode is W1, the width of each adjacent first electrode and second electrode is W2, and the width of any third electrode is W, and the width between each two adjacent third electrodes is W, wherein W = W1 + W2; at least one electrode group includes a first electrode group and a second electrode group, wherein the plurality of first electrodes and the plurality of second electrodes in the first electrode group and the plurality of first electrodes and the plurality of second electrodes in the second electrode group are disposed on both sides of the center of the first electrode plate;

[0056] The capacitance value of the first capacitor and the capacitance value of the second capacitor are collected, including:

[0057] Collect the capacitance value C1 output by the first capacitor in the first electrode group, collect the capacitance value C2 output by the second capacitor in the first electrode group, collect the capacitance value C3 output by the first capacitor in the second electrode group, and collect the capacitance value C4 output by the second capacitor in the first electrode group.

[0058] In other words, when a first electrode group and a second electrode group are arranged with their centers opposite each other about the first electrode plate and the second electrode plate, it is necessary to take the capacitance values ​​formed by the two electrode groups respectively, and then process them using the corresponding signal processing methods.

[0059] In a possible implementation of the second aspect, in either the first electrode group or the second electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposing first side and second side, and the orthographic projection of the first side onto the first electrode plate coincides with the centerline of the first electrode.

[0060] Using the capacitance values ​​of the first capacitor and the second capacitor, the external force F borne by the detection device is measured, including:

[0061] According to the difference formula C1 - =C1-C2 to obtain C1 - According to the difference formula C2 - =C3-C4 to obtain C2 - ; and, according to the summation formula C1 + =C1+C2 to obtain C1 + According to the summation formula C2 + =C3 + C4 to obtain C2 + ;

[0062] Then according to C1 - C2 - C1 + and C2 + Calculate the external force F that the testing equipment bears.

[0063] Here, differential signal processing and sum signal processing are adopted to calculate the F size.

[0064] In this way, not only the capacitance area change increases, but also the force measurement sensitivity can be improved, and through the differential method, the capacitance signal change can be doubled, further improving the measurement sensitivity.

[0065] In a possible implementation of the second aspect, the capacitive force sensor further includes a third electrode plate, the third electrode plate is arranged on a side of the second electrode plate away from the first electrode plate; the at least one electrode group further includes a third electrode group, in the third electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged on a surface of the third electrode plate opposite to the second electrode plate, and the plurality of third electrodes are arranged on a surface of the second electrode plate opposite to the third electrode plate, and the third electrode group and the first electrode group are symmetrically arranged about the second electrode plate; in any one of the first electrode group and the second electrode group, along the arrangement direction of the plurality of first electrodes and the pluralityity of second electrodes, the third electrode includes opposite first and second side edges, and a projection of the first side edge on the first electrode plate is coincident with a center line of the first electrode.

[0066] The capacitance value of the first capacitor is collected, and the capacitance value of the second capacitor is collected, and the method further includes:

[0067] The capacitance value C5 output by the first capacitor in the third electrode group is collected, and the capacitance value C6 output by the second capacitor in the third electrode group is collected.

[0068] The capacitance value of the first capacitor and the capacitance value of the second capacitor are used to measure the external force F borne by the detection device, and the method includes:

[0069] According to the differential formula C1 U- =C2, C1 U- is obtained according to the differential formula C1 D- =C6, C1 D- is obtained.

[0070] According to the sum formula C1 U+ =C1+C2, C1 U+ is obtained according to the sum formula C1 D+ =C5+C6, C1 D+ is obtained.

[0071] According to C1 - =C1 U- +C1 D- and C1 + =C1 U+ -C1 D+ , the external force F borne by the detection device is calculated.

[0072] When the force sensor includes not only the first electrode plate and the second electrode plate, but also a third electrode plate, and the electrode arrangement is symmetrically arranged, the external force F can also be calculated by the differential signal processing and the sum signal processing mode.

[0073] Similarly, by adding a third electrode plate, the capacitance area change can be further increased, and the sensitivity can be improved.

[0074] In a possible implementation of the second aspect, in the first electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the first electrode; in the second electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of a gap between the first electrode and the second electrode.

[0075] The capacitance value of the first capacitor and the capacitance value of the second capacitor are used to measure the external force F borne by the detection device, including:

[0076] According to the differential formula C1 - =C2, C1 - is obtained; and according to the differential formula C2 - =C4, C2 - is obtained.

[0077] According to C1 - and C2 - , the external force F borne by the detection device is calculated.

[0078] When the force sensor adopts the above arrangement, not only for the area change type sensor, but also for the gap change type sensor, only the differential signal processing mode can be used to obtain the size of the external force F.

[0079] In a possible implementation of the second aspect, the capacitive force sensor further includes a third electrode plate disposed on the side of the second electrode plate opposite to the first electrode plate; at least one electrode group further includes a third electrode group; in the third electrode group, a plurality of first electrodes and a plurality of second electrodes are disposed on the surface of the third electrode plate opposite to the second electrode plate, and a plurality of third electrodes are disposed on the surface of the second electrode plate opposite to the third electrode plate; and the third electrode group and the first electrode group are symmetrically arranged about the second electrode plate; in the first electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposing first side and second side, and the orthographic projection of the first side on the first electrode plate coincides with the center line of the first electrode; in the second electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode includes opposing first side and second side, and the orthographic projection of the first side on the first electrode plate coincides with the center line of the gap between the first electrode and the second electrode;

[0080] Collecting the capacitance value of the first capacitor and the capacitance value of the second capacitor also includes:

[0081] Collect the capacitance value C5 output by the first capacitor in the third electrode group, and collect the capacitance value C6 output by the second capacitor in the third electrode group.

[0082] Using the capacitance values ​​of the first capacitor and the second capacitor, the external force F borne by the detection device is measured, including:

[0083] According to the difference formula C1 U- =C1-C2 to obtain C1 U- According to the difference formula C1 D- =C5-C6 to obtain C1 D- ;

[0084] Then according to C1 - =C1 U- +C1 D- Calculate the external force F that the testing equipment bears.

[0085] In other words, when the third electrode plate is present and the electrodes are arranged in the manner described above, the magnitude of the external force in space can be determined solely through differential methods. Attached Figure Description

[0086] Figure 1 This is a simplified structural diagram of a force sensor in the prior art;

[0087] Figure 2 An exploded view of a capacitive force sensor provided in an embodiment of this application;

[0088] Figure 3 for Figure 2 The image shows a cross-sectional view of the assembled capacitive force sensor.

[0089] Figure 4 A connection relationship schematic diagram of an elastic body, a main body and a limiting baffle provided for an embodiment of the present application;

[0090] Figure 5 A structure diagram of a first electrode plate in a capacitive force sensor provided for an embodiment of the present application;

[0091] Figure 6 A structure diagram of a second electrode plate in a capacitive force sensor provided for an embodiment of the present application;

[0092] Figure 7 A structure diagram of a first electrode plate in a capacitive force sensor provided for an embodiment of the present application;

[0093] Figure 8 A structure diagram of a second electrode plate in a capacitive force sensor provided for an embodiment of the present application;

[0094] Figure 9 A cross-sectional view of a first electrode plate and a second electrode plate in a capacitive force sensor provided for an embodiment of the present application;

[0095] Figure 10 An electrode distribution diagram on a first electrode plate and a second electrode plate in a capacitive force sensor provided for an embodiment of the present application;

[0096] Figure 11 A principle diagram of a first capacitor or a second capacitor formed in a capacitive force sensor provided for an embodiment of the present application;

[0097] Figure 12a An electrode distribution diagram on a first electrode plate and a second electrode plate formed in a capacitive force sensor provided for an embodiment of the present application;

[0098] Figure 12b An electrode distribution diagram on a first electrode plate and a second electrode plate formed in a capacitive force sensor provided for an embodiment of the present application;

[0099] Figure 13 A curve diagram of a capacitor formed in Figure 12a and Figure 12b ;

[0100] Figure 14a A curve diagram of a capacitor formed in Figure 13 after difference;

[0101] Figure 14b A curve diagram of a capacitor formed in Figure 13 after addition;

[0102] Figure 15aThe electrode distribution diagram on the first electrode plate and the second electrode plate formed in the capacitive force sensor provided by the embodiment of the present application;

[0103] Figure 15b The electrode distribution diagram on the first electrode plate and the second electrode plate formed in the capacitive force sensor provided by the embodiment of the present application;

[0104] Figure 16 The curve diagram of the capacitor formed in Figure 15a and Figure 15b ;

[0105] Figure 17 The curve diagram of the capacitor formed in Figure 16 after difference;

[0106] Figure 18 The structure diagram of the first electrode plate in the capacitive force sensor provided by the embodiment of the present application;

[0107] Figure 19 The distribution diagram of one of the electrode groups in Figure 18 ;

[0108] Figure 20 The structure diagram of the second electrode plate in the capacitive force sensor provided by the embodiment of the present application;

[0109] Figure 21 The distribution diagram of one of the electrode groups in Figure 20 ;

[0110] Figure 22 The cross-sectional diagram of the first electrode plate, the second electrode plate and the third electrode group in the capacitive force sensor provided by the embodiment of the present application;

[0111] Figure 23 The electrode distribution diagram on the first electrode plate, the second electrode plate and the third electrode group formed in the capacitive force sensor provided by the embodiment of the present application;

[0112] Figure 24a The electrode distribution diagram of the first electrode group and the third electrode group on the first electrode plate, the second electrode plate and the third electrode plate formed in the capacitive force sensor provided by the embodiment of the present application;

[0113] Figure 24b The electrode distribution diagram of the second electrode group and the fourth electrode group on the first electrode plate, the second electrode plate and the third electrode plate formed in the capacitive force sensor provided by the embodiment of the present application;

[0114] Figure 25a The electrode distribution diagram of the first electrode group and the third electrode group on the first electrode plate, the second electrode plate and the third electrode plate formed in the capacitive force sensor provided by the embodiment of the present application;

[0115] Figure 25b The electrode distribution diagram of the second electrode group and the fourth electrode group on the first electrode plate, the second electrode plate and the third electrode plate formed in the capacitive force sensor provided by the embodiment of the present application.

[0116] Reference signs:

[0117] 1000 - capacitive force sensor;

[0118] 10 - main body; 101 - accommodating cavity;

[0119] 20 - sensing electrode plate; 201 - through hole;

[0120] 30 - elastomer electrode plate;

[0121] 40 - elastomer; 401 - connecting part; 402 - elastic arm; 403 - fixed arm;

[0122] 50 - force-receiving plate;

[0123] 60 - connecting column;

[0124] 70 - limiting baffle; 701 - first limiting baffle; 702 - second limiting baffle;

[0125] 80 - circuit board;

[0126] 90 - base;

[0127] 200 - first electrode plate;

[0128] 200a - first insulating substrate;

[0129] 21, 21-1, 21-2, 21-3, 21-4, 2011, 2012, 2031, 2032 - first electrode; 22, 22-1, 22-2, 22-3, 22-4, 2021, 2022, 2041, 2042 - second electrode;

[0130] 300 - second electrode plate;

[0131] 300a - second insulating substrate;

[0132] 31, 31-1, 31-2, 31-3, 31-4, 3011, 3012, 3021, 3022 - third electrode;

[0133] 400 - third electrode plate. DETAILED DESCRIPTION

[0134] In some devices such as robots, aerospace equipment, machining equipment, automobile manufacturing equipment or multi-freedom precise assembly equipment, a force sensor is needed to measure the space force or torque. For example, in a robot, a force sensor is generally used to measure the force or torque on the arm, wrist, finger or base of the robot during movement, and the force sensor can convert the sensed force or torque information into an electrical signal output.

[0135] With the development of the above-mentioned devices, the force sensor has developed from a single-dimensional sensor to a multi-dimensional sensor, such as a six-dimensional sensor, and higher and higher requirements for the sensitivity of the sensor have been put forward. For example, in a robot, even if the arm produces a small displacement under the action of an external force, the force sensor needs to be able to sensitively perceive it to more accurately detect the size of the external force.

[0136] In order to improve the sensitivity of the force sensor detection and improve the use performance of the force sensor, the present application embodiment gives a new type of force sensor, which is a capacitive force sensor based on capacitive change. The capacitive force sensor given by the present application embodiment is described in detail below in combination with the drawings.

[0137] Figure 2 An exploded view of a capacitive force sensor 1000 given by the present application embodiment is shown, Figure 3 is Figure 2 the cross-sectional view after assembly of the structure shown. In combination with Figure 2 and Figure 3 , the capacitive force sensor 1000 includes a main body 10, the main body 10 forms an accommodation cavity 101 inside, the accommodation cavity 101 is provided with an elastic body 40, a sensing electrode plate 20 and an elastic body electrode plate 30; wherein, as Figure 4 shown, Figure 4 a structure diagram of the elastic body 40 is shown, the elastic body 40 includes a connecting portion 401 and a plurality of elastic arms 402 arranged along the circumference of the connecting portion 401, and the end of the elastic arm 402 away from the connecting portion 401 is fixedly connected with the main body 10.

[0138] In addition, the elastic body electrode plate 30 is arranged opposite to the elastic body 40, and the elastic body electrode plate 30 is fixedly connected with the connecting portion 401 of the elastic body 40. In this way, when the elastic body 40 deforms, the elastic body electrode plate 30 will move relative to the main body 10.

[0139] In combination with Figure 2 and Figure 3The inductive electrode plate 20 and the elastomer electrode plate 30 are oppositely arranged, the inductive electrode plate 20 is provided with a through hole 201, and the force receiving plate 50 arranged outside the accommodating cavity 101 of the main body 10 is fixedly connected with the elastomer electrode plate 30 through the connecting column 60 penetrating through the through hole 201. In other words, the force receiving plate 50 for bearing external force is arranged outside the main body 10, and the force receiving plate 50 is fixedly connected with the elastomer electrode plate 30 and the elastomer 40 through the connecting column 60. In this way, when the external force is applied to the force receiving plate 50, the elastomer 40 will be deformed, and the deformation of the elastomer 40 will drive the elastomer electrode plate 30 to move relative to the inductive electrode plate 20.

[0140] In addition, the inductive electrode plate 20 and the elastomer electrode plate 30 are both provided with electrodes, so that when the elastomer electrode plate 30 moves relative to the inductive electrode plate 20, at least one parameter of the opposite area or the spacing between the electrodes on the inductive electrode plate 20 and the electrodes on the elastomer electrode plate 30 changes, thereby causing the capacitance value of the capacitive force sensor 1000 to change, and the capacitance value can be used to represent the size of the external force.

[0141] The electrode arrangement on the inductive electrode plate 20 and the electrode arrangement on the elastomer electrode plate 30 will be described in detail below.

[0142] In another embodiment, the elastomer 40 of the capacitive force sensor 1000 can also include a plurality of fixed arms 403, and the plurality of fixed arms 403 are arranged along the circumference of the connecting portion 401. Figure 4 In addition, the plurality of fixed arms 403 and the plurality of elastic arms 402 can be alternately arranged along the circumference of the connecting portion 401.

[0143] Continuing to combine Figure 4 The capacitive force sensor 1000 further includes a limiting baffle 70, which is used to limit the displacement of the elastomer 40 along the X direction, the Y direction and the Z direction as shown in Figure 4 For example, the limiting baffle 70 can include a plurality of first limiting baffles 701 and a plurality of second limiting baffles 702, wherein two first limiting baffles 701 are oppositely arranged, two second limiting baffles 702 are oppositely arranged, one end of the fixed arm 403 is fixedly connected with the connecting portion 401, and the other end extends into the cavity surrounded by the two first limiting baffles 701 and the two second limiting baffles 702, that is, by limiting the displacement of the fixed arm 403, the displacement of the elastomer 40 is limited.

[0144] In addition, the capacitive force sensor 1000 can also include a plurality of limiting baffles 70, which are used to limit the displacement of the elastomer 40 along the X direction, the Y direction and the Z direction as shown in Figure 2 and Figure 3The capacitive force sensor 1000 given by the embodiments of the present application can further include a circuit board 80, and the circuit board 80 is integrated with a processor. The processor can process the capacitance values output by the sensing electrode plate 20 and the elastic electrode plate 30 to output the external force size.

[0145] Figure 2 One of the ways in which the circuit board 80 is arranged is that the circuit board 80 is also arranged in the accommodating cavity 301 of the main body 10, and the circuit board 80 and the elastic electrode plate 30 are arranged on opposite sides of the elastic body 40. Figure 2 Only one of the ways in which the circuit board 80 is arranged is shown, and of course, the circuit board 80, the elastic electrode plate 30 and the sensing electrode plate 20 are all arranged on the same side of the elastic body 40.

[0146] In addition, in combination with Figure 2 and Figure 3 , the capacitive force sensor 1000 can further include a base 90, and the base 90 is fixedly connected with the main body 10. In some optional embodiments, the main body 10, the base 90 and the force receiving plate 50 can enclose a closed accommodating cavity 101, so that the sensing electrode plate 20, the elastic electrode plate 30, the circuit board 80 and the elastic body 40 are arranged in the closed cavity to prevent these devices from being polluted by external dust and other impurities.

[0147] In Figure 2 and Figure 3 shown, since the elastic electrode plate 30 is fixedly connected with the elastic body 40, the elastic electrode plate 30 can move relative to the sensing electrode plate 20 as a fixed electrode plate 10 to change the capacitance as a movable electrode plate.

[0148] The electrode arrangement on the electrode plate for forming a capacitor and the processing method of the generated capacitance of the present application are described in detail below.

[0149] As shown in Figure 5 and Figure 6 , Figure 5 shown is a structure diagram of a first electrode plate 200 with an electrode given by the embodiments of the present application, Figure 6 shown is a structure diagram of a second electrode plate 300 with an electrode given by the embodiments of the present application. One of the first electrode plate 200 and the second electrode plate 300 is a movable electrode plate, and the other is a fixed electrode plate. The movable electrode plate can be fixedly connected with the elastic body 40 in the above Figure 2 and Figure 3 , and when the elastic body deforms, the relative movement between the first electrode plate 200 and the second electrode plate 300 is promoted.

[0150] The movement of the moving electrode plate relative to the fixed electrode plate in this application includes at least: movement of the moving electrode plate relative to the fixed electrode plate in a direction parallel to the fixed electrode plate; movement of the moving electrode plate relative to the fixed electrode plate in a direction perpendicular to the fixed electrode plate; rotation of the moving electrode plate relative to the fixed electrode plate along an axis parallel to the fixed electrode plate; and rotation of the moving electrode plate relative to the fixed electrode plate along an axis parallel to the fixed electrode plate. For example, such as... Figure 2 , Figure 5 and Figure 6 As shown, the moving electrode plate can translate relative to the fixed electrode plate along the X, Y, and Z axes, and can also rotate around the X, Y, and Z axes. Thus, the force sensor provided in this application is not only an area-change type sensor, but also a spacing-change type sensor, using these two different types of sensors to measure the spatial magnitude of external forces.

[0151] In some alternative implementations, the first electrode plate 200 here can be as described above. Figure 2 and Figure 3 The induction electrode plate 20 and the second electrode plate 300 shown can be the ones described above. Figure 2 and Figure 3 The elastomeric electrode plate 30 is shown. In some alternative embodiments, the first electrode plate 200 may also be as described above. Figure 2 and Figure 3 The elastomer electrode plate 30 shown, and the second electrode plate 300 can be the aforementioned Figure 2 and Figure 3 The induction electrode plate 20 is shown. For ease of understanding, the following embodiments of this application use the first electrode plate 200 as an example. Figure 2 The induction electrode plate 20 and the second electrode plate 300 are... Figure 2 Taking the elastomer electrode plate 30 as an example, we will introduce the electrode distribution and signal processing method.

[0152] like Figure 5 As shown, the first electrode plate 200 has multiple groups of sensing electrodes. Figure 5 Eight sensing electrode groups are illustrated exemplarily, with (201, 202) constituting one sensing electrode group, and similarly, (203, 204), (205, 206), (207, 208), (209, 210), (211, 212), (213, 214), and (215, 216) constituting the remaining seven sensing electrode groups. Figure 6 As shown, the second electrode plate 300 has multiple grounding electrode groups. Figure 6 Eight grounding electrode groups are shown as an example, namely grounding electrode group 301 to grounding electrode group 308.

[0153] Combined Figure 5 and Figure 6 , Figure 5 The sensing electrode group 201 and its relationship withFigure 6 The grounding electrode group 301 in the middle can form a capacitor. Figure 5 The sensing electrode group 202 and with Figure 6 The grounding electrode group 301 in the middle can also form another capacitor. Similarly, Figure 5 The sensing electrode group 203 and its relationship with Figure 6 The grounding electrode group 302 in the middle can form another capacitor. Figure 5 The sensing electrode group 204 and its relationship with Figure 6 The grounding electrode group 302 in the middle can form another capacitor.

[0154] In that case, Figure 5 The first electrode plate 200 shown and Figure 6 The second electrode plate 300 shown can form 16 capacitors. When the capacitive force sensor is in use, the two sets of capacitors arranged along the X direction (also called the first direction) can be used to measure the force Fx in the X direction, the torque My about the Y direction (also called the second direction perpendicular to the first direction), and the force Fz in the Z direction (also called the third direction perpendicular to both the first and second directions). The two sets of capacitors arranged in the Y direction are used to measure the force Fy in the Y direction, the torque Mx about the X direction axis, and the force Fz in the Z direction. The remaining four sets of capacitors arranged in a ring are mainly used to measure the torque Mz about the Z direction axis and the force Fz in the Z direction, and can also measure Mx and My.

[0155] When using Figure 7 and Figure 8 The electrode arrangement shown forms a capacitive force sensor, which is a six-dimensional force sensor. In other alternative implementations, such as... Figure 5 and Figure 6 As shown, it is possible to Figure 7 and Figure 8 Based on this, the induction electrode groups (209, 210), (211, 212), (213, 214), and (215, 216) on the first electrode plate 200 are removed. Correspondingly, the grounding electrode groups 305 to 308 on the second electrode plate 300 are removed. With this design, Figure 7 and Figure 8 The capacitive force sensor formed by the structure shown is a five-dimensional force sensor, which can measure the force Fx in the X direction, the torque My about the Y axis, the force Fz in the Z direction, the force Fy in the Y direction, and the torque Mx about the X axis.

[0156] Of course, in other alternative implementations, it is possible to Figure 5 and Figure 6On the basis of the above, the inductive electrode groups (203, 204), (207, 208) are removed, and the ground electrode group 302 and the ground electrode group 304 are removed, so that the force Fx, the force Fz, and the force Fy can be measured.

[0157] As shown in Figure 5 and Figure 6 , in the first electrode plate 200, the electrodes in the inductive electrode group (201, 202) and the electrodes in the inductive electrode group (203, 204) are arranged along the X direction, and the electrodes in the inductive electrode group (205, 206) and the electrodes in the inductive electrode group (207, 208) are arranged along the Y direction, and then it can be considered that the electrodes in the inductive electrode group (201, 202), the electrodes in the inductive electrode group (203, 204), the electrodes in the inductive electrode group (205, 206), and the electrodes in the inductive electrode group (207, 208) are linearly arranged, and then, correspondingly, in the second electrode plate 300, the electrodes in the ground electrode group 301, the electrodes in the ground electrode group 302, the electrodes in the ground electrode group 303, and the electrodes in the ground electrode group 304 are also linearly arranged.

[0158] However, in combination with Figure 5 to Figure 8 and Figure 2 , in the first electrode plate 200, the electrodes in the inductive electrode group (209, 210), the electrodes in the inductive electrode group (211, 212), the electrodes in the inductive electrode group (213, 214), and the electrodes in the inductive electrode group (215, 216) are arranged in an arc shape along the circumference of the first electrode plate 200, and then the four inductive electrode groups are angularly arranged. Correspondingly, in the second electrode plate 300, the electrodes in the ground electrode group 305, the electrodes in the ground electrode group 306, the electrodes in the ground electrode group 307, and the electrodes in the ground electrode group 308 are also angularly arranged. For example, in the four groups of capacitors arranged angularly, the included angle between the arrangement direction of the inductive electrode group (209, 210) and the Y direction is -45°, and the included angle between the arrangement direction of the inductive electrode group (213, 214) and the Y direction is 45°, that is, the eight inductive electrode groups are arranged at equal intervals along the circumference of the first electrode plate 200.

[0159] It should be noted that the first electrode plate 200 and the second electrode plate 300 shown in the above Figure 3 can be arranged in the capacitive force sensor structure shown in Figure 9 and Figure 10 , or can be arranged in other structures of capacitive force sensor structures.

[0160] In addition, the sensing electrode groups (201, 202) on the first electrode plate 200 and the grounding electrode group 301 on the second electrode plate 300 can be collectively referred to as one electrode group. Furthermore, the same sensing electrode groups (203, 204) and the grounding electrode group 302 can be collectively referred to as another electrode group.

[0161] The electrode groups belonging to the linear arrangement and the electrode groups belonging to the angular arrangement will be introduced respectively as follows.

[0162] The specific arrangement of the electrode groups belonging to the linear arrangement and the signal processing method will be introduced as follows by taking the sensing electrode groups (201, 202) on the first electrode plate 200 and the grounding electrode group 301 on the second electrode plate 300 as an example.

[0163] Figure 9 A cross-sectional view showing part of the structure of the opposite first electrode plate 200 and second electrode plate 300 is shown in Figure 9 Figure 10 A distribution diagram of the electrodes on the electrode plates of the structure shown in Figure 9 Figure 9 The first electrode plate 200 has an A1 surface opposite to the second electrode plate 300, and the second electrode plate 300 has a B1 surface opposite to the first electrode plate 200, i.e. the A1 surface is opposite to the B1 surface. The sensing electrode groups (201, 202) are arranged on the A1 surface, and the grounding electrode group 301 is arranged on the B1 surface, wherein the sensing electrode groups (201, 202) include a plurality of first electrodes 21 and a plurality of second electrodes 22, and the grounding electrode group 301 includes a plurality of third electrodes 31.

[0164] In some alternative embodiments, as shown in Figure 10 The first electrode plate 200 includes a first insulating substrate 200a, and the plurality of first electrodes 21 and the plurality of second electrodes 22 are formed on the surface of the first insulating substrate 200a opposite to the second electrode plate 300. Similarly, the second electrode plate 300 includes a second insulating substrate 300a, and the plurality of third electrodes 31 are formed on the surface of the second insulating substrate 300a opposite to the first electrode plate 200. In some alternative processes, the plurality of first electrodes 21, the plurality of second electrodes 22 and the plurality of third electrodes 31 can be formed by metal wires on insulating substrates. In addition, the plurality of first electrodes 21 are electrically connected to each other, the plurality of second electrodes 22 are electrically connected to each other, and the plurality of third electrodes 31 are also electrically connected to each other.

[0165] As shown in Figure 9 Figure 10 ​​​For example, the first electrode 21 in the inductive electrode group (201, 202) arranged on the first electrode plate 200 is exemplarily given four, which are the first electrode 21-1, the first electrode 21-2, the first electrode 21-3 and the first electrode 21-4, which are electrically connected with each other. And the second electrode 22 in the inductive electrode group (201, 202) is also exemplarily given four, which are the second electrode 22-1, the second electrode 22-2, the third electrode 22-3 and the second electrode 22-4, which are electrically connected with each other. In addition, the plurality of first electrodes and the plurality of second electrodes are arranged alternately along the X direction, for example, the first electrode 21-1, the second electrode 22-1, the first electrode 21-2, the second electrode 22-2, the first electrode 21-3, the third electrode 22-3, the first electrode 21-4 and the second electrode 22-4 are arranged along the X direction in turn.

[0166] Continuing to combine Figure 9 and Figure 10 , the first electrode 21, the third electrode 31 and the second electrode 22 are arranged staggered along the X direction. For example, as shown in Figure 9 and Figure 9 , the third electrode 31 in the grounding electrode group 301 arranged on the second electrode plate 300 is exemplarily given four, which are the third electrode 31-1, the third electrode 31-2, the third electrode 31-3 and the third electrode 31-4, which are electrically connected with each other. And any third electrode 31 forms a coupling structure with its adjacent first electrode 21 and second electrode 22, and any first electrode 21 and any second electrode 22 belong to an independent coupling structure, for example, as shown in Figure 10 , the first electrode 21-1, the second electrode 22-1 and the third electrode 31-1 belong to the coupling structure Q1, and the first electrode 21-2, the second electrode 22-2 and the third electrode 31-2 belong to another independent coupling structure Q2. It can also be understood that there will be no third electrode between the adjacent second electrode 22-1 and the first electrode 21-2, that is, any first electrode 21, any second electrode 22 and any third electrode 31 only belong to an independent coupling structure, and cannot be in two coupling structures at the same time, that is, the number of first electrodes 21 is equal to the number of second electrodes 22, and the number of third electrodes 31 is equal to or less than the number of first electrodes 21, Figure 9 and Figure 10 Exemplarily, the number of first electrodes 21, the number of second electrodes 22 and the number of third electrodes 31 are equal.

[0167] Based on Figure 10 and Figure 9the design, when the second electrode plate 300 moves relative to the first electrode plate 200, the plurality of first electrodes 21 and the plurality of third electrodes 31 form a first capacitor, and the plurality of second electrodes 22 and the plurality of third electrodes 31 form a second capacitor. For example, in Figure 10 , four first electrodes 21 and four third electrodes 31 form a first capacitor, and four second electrodes 22 and four third electrodes 31 form a second capacitor.

[0168] From the above Figure 9 and Figure 9 It can be seen that the capacitive force sensor given in the present application is a kind of capacitive grid sensor structure, in this grid structure, such as Figure 10 , when the second electrode plate 300 moves relative to the first electrode plate 200 along the X direction by ΔX, the area change of the first capacitor and the second capacitor of the present application is N×H×ΔX, where N represents the number of the least number of first electrodes, second electrodes or third electrodes, or the number of coupling structures, and H represents the size of the second electrode plate 300 along the Y direction, but in the prior art, when the movable electrode plate moves relative to the fixed electrode plate by ΔX, the area change of the capacitor is only H×ΔX, and further, compared with N×H×ΔX and H×ΔX, the area change of the present application is significantly increased, when the area change is significantly increased, the corresponding capacitance change is also multiplied, and further, the sensitivity of the capacitive force sensor can be effectively improved, so that when the displacement of the second electrode plate 300 relative to the first electrode plate 200 in the X direction is small, the displacement can also be sensitively detected, thereby measuring the size of the external force.

[0169] In combination with Figure 11 and Figure 11 , by arranging a plurality of first electrodes 21 and second electrodes 22 alternately on the first electrode plate 200 to form a first capacitor and a second capacitor with the plurality of third electrodes 31 on the second electrode plate 300, the size of the first electrode plate 200 and the second electrode plate 300 along the X direction can be increased without increasing the size of the first electrode plate 200 and the second electrode plate 300 along the X direction, or reducing the distance between the first electrode plate 200 and the second electrode plate 300 along the Z direction. Such design will not increase the size of the two electrode plates as a whole, and will not challenge the installation process of the first electrode plate 200 and the second electrode plate 300.

[0170] In combination with Figure 10 , as shown in Figure 11 , the principle of forming a first capacitor or a second capacitor is shown. For example, in combination with Figure 9 and Figure 10, the first electrode 21-1, the first electrode 21-2, the first electrode 21-3 and the first electrode 21-4 are connected in parallel, have an output terminal L1, the third electrode 31-1, the third electrode 31-2, the third electrode 31-3 and the third electrode 31-4 are connected in parallel, have an output terminal L3, and the electrical signals output by the output terminal L1 and the output terminal L3 show the capacitance value C1 of the first capacitor. Similarly, the second electrode 22-1, the second electrode 22-2, the third electrode 22-3 and the second electrode 22-4 are connected in parallel, have an output terminal L2, the third electrode 31-1, the third electrode 31-2, the third electrode 31-3 and the third electrode 31-4 are connected in parallel, have an output terminal L3, and the electrical signals output by the output terminal L2 and the output terminal L3 show the capacitance value C2 of the second capacitor. That is, by connecting the multiple variable capacitors in parallel, a capacitor is formed, so that the capacitance variation amount can be increased, and the measurement sensitivity can be improved.

[0171] Continuing to combine Figure 10 and Figure 12a , along the X direction, the linear width of any first electrode 21 and any second electrode 22 is W1, the linear width of each adjacent first electrode 21 and second electrode 22 is W2, and the linear width of any third electrode is W, and the linear width between each adjacent two third electrodes 31 is W, wherein W = W1 + W2. In this way, the arrangement period of the first electrode 21 is 2W, and the arrangement period of the second electrode 22 is also 2W, the width of each first electrode 21 and each second electrode 22 along the X direction is W1, the distance between each adjacent first electrode 21 and second electrode 22 is W2, the width of each third electrode 31 along the X direction is W = W1 + W2, and the distance between each adjacent two third electrodes 31 is W = W1 + W2.

[0172] When the first electrode, the second electrode and the third electrode are defined by the above dimensions, the amount of movement of the elastic body 40 caused by the maximum force in the X direction should not exceed W1 / 2.

[0173] In addition, the orthographic projection of the first electrode 21 and the second electrode 22 on the second electrode plate 300 covers the third electrode 31 along the Y direction perpendicular to the X direction. That is, along the Y direction, the size of the first electrode 21 and the second electrode 22 is larger than the size of the third electrode 31. Alternatively, in some other embodiments, the orthographic projection of the third electrode 31 on the first electrode plate 200 covers the first electrode 21 and the second electrode 22 along the Y direction perpendicular to the X direction. That is, along the Y direction, the size of the third electrode 31 is larger than the size of the first electrode 21 and the second electrode 22. In summary, the size of the third electrode 31 along the Y direction is not equal to the size of the first electrode 21 along the Y direction, for example, as shown in Figure 12aAs shown, along the Y direction, the size of the third electrode 31 is H2, and the size of the first electrode 21 and the second electrode 22 is H1, and H1 is not equal to H2.

[0174] When the first electrode 21, the second electrode 22, and the third electrode 31 are subject to the aforementioned dimensional constraints in the Y direction, and the first electrode plate 200 and the second electrode plate 300 move relative to each other in the X direction, even if a small displacement occurs in the Y direction, the effective area between the first electrode plate and the second electrode plate will not change due to the displacement in the Y direction. Therefore, the accuracy of the measurement data can be guaranteed.

[0175] The positional relationship between the first and second electrodes in the induction electrode group (201, 202) and the corresponding third electrode in the grounding electrode group 301 is described below.

[0176] Figure 12a One positional relationship is given, specifically, in the grounding electrode group 301, along the arrangement direction of the multiple third electrodes (i.e., along...). Figure 12b In the X direction), the third electrode includes a first side M1 and a second side M2, the orthogonal projection of the first side M1 onto the first electrode plate 200 coincides with the centerline of the first electrode. For example, in Figure 12b In the middle, the orthographic projection on the first electrode plate 200 of the first side M1 of the third electrode 31-1 coincides with the center line T1 of the first electrode 21-1. Since the linear width of the third electrode is half of the arrangement period of the first electrode, the orthographic projection on the first electrode plate 200 of the second side M2 ​​of the third electrode 31-1 coincides with the center line T2 of the second electrode 22-1.

[0177] Figure 12a The positional relationship between the first and second electrodes in the induction electrode group (203, 204) and the corresponding third electrode in the grounding electrode group 302 is given. Figure 12b As shown, the positional relationship between the first electrode, the second electrode, and the third electrode is... Figure 13 As shown, also in the grounding electrode group 302, along the arrangement direction of the multiple third electrodes (i.e., along... Figure 13 The third electrode (in the X direction) includes a first side M1 and a second side M2, with the orthographic projection of the first side M1 onto the first electrode plate 200 coinciding with the centerline of the first electrode. In other words, the third electrode is symmetrically positioned between the first and second electrodes.

[0178] Figure 12aA graph showing the capacitance C1 output of the capacitor formed by inductive electrode group 201 and ground electrode group 301 versus the X-displacement is provided. Similarly, a graph showing the capacitance C2 output of the capacitor formed by inductive electrode group 202 and ground electrode group 301 versus the X-displacement is also provided. Since the positional relationships between the electrodes in inductive electrode groups 203, 204, and 302 are the same as those between the electrodes in inductive electrode groups 201, 202, and 301, the graphs showing the capacitance C3 output of the capacitor formed by inductive electrode group 203 and ground electrode group 302 versus the X-displacement, and the graphs showing the capacitance C4 output of the capacitor formed by inductive electrode group 204 and ground electrode group 302 versus the X-displacement are also provided. Figure 12b As shown, curve C3 is the same as curve C1, and curve C2 is the same as curve C4.

[0179] When the first electrode group on the first electrode plate 200 and the second electrode plate 300 is as follows Figure 14a The arrangement shown includes the second electrode group on the first electrode plate 200 and the second electrode plate 300, as follows: Figure 14a As shown, this application provides a method for calculating the magnitude of an external force F using the output capacitance value. Specifically, it includes performing differential processing on the capacitance value C1 of the first capacitor formed by the induction electrode group 201 and the ground electrode group 301, and the capacitance value C2 of the second capacitor formed by the induction electrode group 202 and the ground electrode group 301 to obtain C1. - =C1-C2, differential signal C1 - Curves Figure 13 As shown, by Figure 12b The differential signal C1 - Compared to the curve Figure 14a From the curves of capacitance values ​​C1 and C2, it is easy to see that, under the same displacement X change, the change in the magnitude of the differential signal is twice the change in the magnitude of capacitance value C1 or C2. In this way, the sensitivity of the force sensor signal will be significantly improved.

[0180] Similarly, this can be applied to... Figure 14a In the second electrode group shown, the capacitance value C3 of the first capacitor formed by the induction electrode group 203 and the ground electrode group 302, and the capacitance value C4 of the second capacitor formed by the induction electrode group 204 and the ground electrode group 302 are also differentially processed to obtain C2. - =C3-C4, differential signal C2 - Curves are also like Figure 12a As shown.

[0181] However, by Figure 12bAs can be seen, when the movable electrode plate moves only in the Z direction relative to the fixed electrode plate, and X is zero, because the values of the capacitance C1 and the capacitance C2 are always equal, the difference C1 - is zero. Also, even if X is kept at a position other than zero and is not changed, only moving in the Z direction, the size of the difference signal C1 - changes less than the size change of the capacitance C1 or the capacitance C2, and the closer X is to zero, the smaller the size change. Also, when the sensing electrode group and the ground electrode group are arranged as shown in Figure 12a and Figure 12b , for the area change type force sensor, using the difference signal processing can significantly improve the measurement sensitivity, but for the pitch change type force sensor, using only the difference signal processing method, the effect on the improvement of the sensitivity is not very obvious.

[0182] For this reason, for the electrode arrangement shown in Figure 14b and Figure 14b , the present application further provides a signal processing method, that is, the sum signal processing method. In other words, the capacitance C1 of the first capacitor formed by the sensing electrode group 201 and the ground electrode group 301, and the capacitance C2 of the second capacitor formed by the sensing electrode group 202 and the ground electrode group 301 are processed by summing to obtain C1 + = C1 + C2, and the sum signal C1 + is as shown in Figure 12a . As can be seen from Figure 12b , when the movable electrode plate moves only in the Z direction relative to the fixed electrode plate, whether X is kept at the zero position or X is kept at a position other than zero, the change of the sum signal C1 + is a constant, that is, the change of the sum signal C1 + is the same as the signal change of the pitch change type capacitor.

[0183] Further, when the electrode arrangement shown in Figure 14a and Figure 14b is used, the difference signal shown in Figure 5 and the sum signal shown in Figure 6 can be combined to calculate the size of the external force received.

[0184] As shown in Figure 12a and Figure 12b , the sensing electrode groups (205, 206) and the ground electrode group 303, and the sensing electrode groups (207, 208) and the ground electrode group 304 arranged along the Y axis are also arranged as shown in Figure 12a and Figure 12bThe differential signal processing method and the sum signal processing method can be combined. In addition, for the angularly arranged sensing electrode groups (209, 210) and the ground electrode group 305, and the sensing electrode groups (211, 212) and the ground electrode group 306, the structures shown in Figure 12a and Figure 12b can be arranged as shown in Figure 2 and Figure 5 The differential signal processing method and the sum signal processing method can be combined.

[0185] In some embodiments, the capacitive force sensor provided in the present application can further include a processor which can be arranged on the circuit board 80 as shown in Figure 6 The processor can process the capacitance values to obtain the magnitude of the external force in space. For example, when the electrode arrangement of the 16 capacitors on the first electrode plate 200 and the second electrode plate 300 is as shown in Figure 12a and Figure 12b The arrangement shown in Figure 5 and Figure 6 The final eight differential signals C1 - to C8 - and eight sum signals C1 + to C8 + can be obtained. Since the structure shown in Figure 15a and Figure 15b can measure the six-dimensional force in space, the six-dimensional force in space can be represented as wherein, A is a constant matrix,

[0186] In some other embodiments, Figure 15a and Figure 15a provide another positional relationship of the electrode arrangement of the first electrode group and the second electrode group on the first electrode plate 200 and the second electrode plate 300. In this embodiment, in the first electrode group, along the arrangement direction of the plurality of third electrodes (i.e. along the X direction of Figure 15b , the third electrode includes opposite first and second side edges M1 and M2, and the orthogonal projection of the first side edge M1 on the first electrode plate 200 coincides with the center line of the first electrode. For example, in Figure 13In the second electrode group, the normal projection of the first side edge Ml of the third electrode 31-1 on the first electrode plate 200 coincides with the center line T3 of the interval between the first electrode 21-1 and the second electrode 22-1, and because the width of the third electrode is half of the arrangement period of the first electrode, the normal projection of the second side edge M2 of the third electrode 31-1 on the first electrode plate 200 coincides with the center line T4 of the interval between the second electrode 22-1 and the first electrode 21-2.

[0187] However, in the second electrode group formed by the sensing electrode group 203, the sensing electrode group 204 and the corresponding ground electrode group 302, as shown in Figure 13 , the normal projection of the first side edge Ml of the third electrode 31-1 on the first electrode plate 200 coincides with the center line T3 of the interval between the first electrode 21-1 and the second electrode 22-1, and because the width of the third electrode is half of the arrangement period of the first electrode, the normal projection of the second side edge M2 of the third electrode 31-1 on the first electrode plate 200 coincides with the center line T4 of the interval between the second electrode 22-1 and the first electrode 21-2.

[0188] In the first electrode group, the capacitance value Cl output by the capacitor formed by the sensing electrode group 201 and the ground electrode group 301 and the curve of the capacitance value Cl varying with the displacement along X is as shown in Figure 16 , and the curve of the capacitance value C2 output by the capacitor formed by the sensing electrode group 202 and the ground electrode group 301 and the curve of the capacitance value C2 varying with the displacement along X is as shown in Figure 17 . However, in the second electrode group, the capacitance value C3 output by the capacitor formed by the sensing electrode group 203 and the ground electrode group 302 and the curve of the capacitance value C3 varying with the displacement along X is as shown in Figure 17 , and the curve of the capacitance value C4 output by the capacitor formed by the sensing electrode group 204 and the ground electrode group 302 and the curve of the capacitance value C4 varying with the displacement along X is as shown in Figure 5 . - The difference between the capacitance value Cl and the capacitance value C2 is C1 - =C1-C2, and the difference between the capacitance value C3 and the capacitance value C4 is C2 - =C3-C4. - The curves of C1 - and C2 - varying with the displacement along X are shown in Figure 6 It is easy to prove that when the moving electrode plate moves only in the Z direction relative to the fixed electrode plate, the difference C1 - is zero, but one of the capacitance value C3 and the capacitance value C4 is at the maximum value and the other is at the minimum value, and the difference C2 - is at the extreme value and can represent the capacitance value of the interval change.

[0189] When Figure 15a and Figure 15bThe electrode arrangement of the 16 capacitors on the first electrode plate 200 and the second electrode plate 300 shown in the figure is as follows Figure 15a and Figure 15b When the electrode arrangement shown in the figure is adopted, eight differential signals C1 - to C8 - may be finally obtained. Then, the spatial six-dimensional force can be represented as wherein, A is a constant matrix,

[0190] It can also be understood that, for the two different electrode arrangements, the application gives two different signal processing methods. These two different electrode arrangements and two different signal processing methods can improve the sensitivity of force measurement not only for capacitors of the area change type but also for capacitors of the pitch change type. In addition, when the electrode arrangement shown in Figure 18 and Figure 19 is adopted, the computational complexity of the signal processing method is reduced, so that the measurement rate can be improved, and the user experience can be further improved.

[0191] The above describes that when the capacitor includes the first electrode plate 200 and the second electrode plate 300, at least two electrode arrangement modes and corresponding signal processing methods are given. In summary, the capacitive sensor for measuring force not only increases the area change, but also can double the capacitance change by using the differential signal processing method to improve the sensitivity of measurement.

[0192] In addition, the capacitive sensor given by the application can also weaken or even eliminate signal crosstalk and realize force decoupling. Specifically, the capacitance change of the area change type capacitor along the X direction and the capacitance change of the area change type capacitor along the Y direction do not affect each other. The capacitance change of the area change type capacitors along the X and Y directions and the capacitance change of the two 45° direction arranged area change type capacitors affect each other very slightly. In addition, the capacitance change of the area change type capacitor and the capacitance change of the pitch change type capacitor affect each other very slightly.

[0193] The above gives the electrode group arranged in a linear manner and the corresponding signal processing method. The specific arrangement mode of the electrode group arranged in an angular manner and the corresponding signal processing method are introduced below. Figure 18 and Figure 19

[0194] Figure 18 An implementable arrangement mode of the angularly arranged sensing electrode groups (209, 210), the sensing electrode groups (211, 212), the sensing electrode groups (213, 214), and the sensing electrode groups (215, 216) on the first electrode plate 200 is given, Figure 19 ​is an enlarged view of the electrode arrangement of the inductive electrode group (209, 210). It is combined with Figure 20 and Figure 21 The plurality of first electrodes and the plurality of second electrodes of the inductive electrode group (209, 210) are arranged alternately along the circumference of the first electrode plate 200, such as the first electrode 21-1, the second electrode 22-1, the first electrode 21-2, the second electrode 22-2, the first electrode 21-3, the second electrode 22-3, the first electrode 21-4, the second electrode 22-4 and the first electrode 21-5 arranged along the circumference of the first electrode plate 200 in turn.

[0195] In addition, the angular width of any first electrode 21 and any second electrode 22 is W1, the angular width of each adjacent first electrode 21 and second electrode 22 is W2, the arrangement period of the first electrode 21 is 2W, the arrangement period of the second electrode 22 is also 2W, and W=W1+W2.

[0196] Figure 20 An implementable arrangement mode of the angularly arranged ground electrode groups 305 to 308 on the second electrode plate 300 is given, Figure 21 is an enlarged view of the electrode arrangement of the ground electrode group 305. It is combined with Figure 18 to Figure 21 and Figure 12a The plurality of third electrodes of the ground electrode group are arranged along the circumference of the second electrode plate 300 in turn, such as the third electrode 31-1, the third electrode 31-2, the third electrode 31-3 and the third electrode 31-4 arranged along the circumference of the second electrode plate 300 in turn.

[0197] The angular width of any third electrode is W, and the angular width between each adjacent two third electrodes 31 is W, wherein W=W1+W2.

[0198] For the electrodes on the first electrode plate 200 and the second electrode plate 300 shown in Figure 12b , the positional relationship between the angularly arranged first electrodes, second electrodes and third electrodes includes at least two cases, such as can be arranged according to the arrangement mode shown in Figure 15a and Figure 15b , or can also be designed according to the arrangement mode shown in Figure 12a and Figure 12b .

[0199] If the angularly arranged electrode group is arranged according to the arrangement mode shown in Figure 15a and Figure 15b , the signal processing method can refer to the above, that is, differential signal processing and sum signal processing are used to obtain the size of the spatial external force. If the angularly arranged electrode group is arranged according to the arrangement mode shown in Figure 22 and Figure 22The signal processing method can refer to the above method, that is, only differential signal processing is used to calculate the size of the spatial force.

[0200] The above force sensor is exemplarily given as a force sensor structure including the first electrode plate 200 and the second electrode plate 300. Another force sensor structure is given below, as shown in Figure 23 As shown, the force sensor structure not only includes the first electrode plate 200 and the second electrode plate 300 shown in the above embodiment, but also includes a third electrode plate 400, Figure 22 The cross-sectional view of the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400 is shown. Figure 22 The electrode distribution diagram of the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400 is given.

[0201] As shown in Figure 22 , the third electrode plate 400 is arranged on the side of the second electrode plate 300 away from the first electrode plate 200. When the second electrode plate 300 is a fixed electrode plate, the first electrode plate 200 and the third electrode plate 400 are both movable electrode plates that can move relative to the second electrode plate 300. In some other embodiments, when the second electrode plate 300 is a movable electrode plate, the first electrode plate 200 and the third electrode plate 400 are both fixed electrode plates.

[0202] Figure 23 The movement direction of the movable electrode plate in the above force sensor structure at least includes: the movable electrode plate moves relative to the fixed electrode plate along a direction parallel to the fixed electrode plate, the movable electrode plate moves relative to the fixed electrode plate along a direction perpendicular to the fixed electrode plate, the movable electrode plate rotates relative to the fixed electrode plate along an axis parallel to the fixed electrode plate, and the movable electrode plate rotates relative to the fixed electrode plate along an axis parallel to the fixed electrode plate. For example, as shown in Figure 22 and Figure 22 , the movable electrode plate moves relative to the fixed electrode plate along the X-axis, the Y-axis and the Z-axis, and can also rotate around the X-axis, the Y-axis and the Z-axis. As with the above force sensor structure including the first electrode plate 200 and the second electrode plate 300, Figure 23 The force sensor structure given above not only belongs to the area change type sensor, but also belongs to the pitch change type sensor.

[0203] In combination with Figure 22 and Figure 23The embodiment can be understood as follows: the first electrode plate 200 has an A1 surface opposite to the second electrode plate 300, the second electrode plate 300 has a B1 surface opposite to the first electrode plate 200, the A1 surface is provided with the first electrodes 21 and the second electrodes 22 arranged alternately, and the B1 surface is provided with the third electrodes 31 staggered with the first electrodes 21 and the second electrodes 22. The positional relationship, size constraint of the first electrodes 21, the second electrodes 22 and the third electrodes 31 have been described above, and will not be described here again.

[0204] In addition, in combination with Figure 22 and Figure 23 , the second electrode plate 300 has a B2 surface opposite to the third electrode plate 400, the third electrode plate 400 has a C1 surface opposite to the second electrode plate 300, the B2 surface is provided with the third electrodes 31, and the C1 surface is provided with the first electrodes 21 and the second electrodes 22. The electrode arrangement on the B2 surface and the C1 surface can be symmetrically arranged as shown in Figure 22 .

[0205] As shown in Figure 23 , the first electrodes 21 on the A1 surface and the third electrodes 31 on the B1 surface form a capacitor, and the output capacitance is C1, the second electrodes 22 on the A1 surface and the third electrodes 31 on the B1 surface form another capacitor, and the output capacitance is C2; in addition, the first electrodes 21 on the C1 surface and the third electrodes 31 on the B2 surface form a capacitor, and the output capacitance is C5, and the second electrodes 22 on the C1 surface and the third electrodes 31 on the B2 surface form another capacitor, and the output capacitance is C6. In this way, Figure 5 , Figure 6 and Figure 24a , Figure 24b in combination, the force sensor provided by the embodiment includes 32 capacitors, compared with the force capacitor structure including the first electrode plate 200 and the second electrode plate 300, the number of capacitors is obviously increased, and the area change amount can also be increased, and the measurement sensitivity is improved.

[0206] For the convenience of the following description, as shown in Figure 24a , the electrode groups on the B1 surface and the A1 surface can be called first electrode groups, and the electrode groups on the B2 surface and the C1 surface can be called third electrode groups. It can be said that the first electrode groups and the third electrode groups are arranged on opposite sides of the second electrode plate 300; in addition, on the first electrode plate 200 and the second electrode plate 300, as shown in Figure 24bThe second electrode group is arranged opposite to the first electrode group with respect to the center of the first electrode plate 200 and the second electrode plate 300, and the fourth electrode group is arranged opposite to the second electrode group with respect to the second electrode plate 200.

[0207] Different arrangements of the electrodes of the first electrode group, the second electrode group, the third electrode group and the fourth electrode group are shown below in connection with the drawings.

[0208] As shown in the first electrode group and the third electrode group, Figure 24a the first side edge of the opposite two side edges of the third electrode on the second electrode plate 300 coincides with the center line T1 of the first electrode, and the second side edge coincides with the center line T2 of the second electrode. For example, in the first electrode group, the opposite two side edges of the third electrode 3011 respectively coincide with the center line T1 of the first electrode 2011 and the center line T2 of the second electrode 2021 on the corresponding first electrode plate 200, and similarly, the opposite two side edges of the third electrode 3012 respectively coincide with the center line T1 of the first electrode 2012 and the center line T2 of the second electrode 2022 on the corresponding third electrode plate 400; in the third electrode group, the opposite two side edges of the third electrode 3021 respectively coincide with the center line T1 of the first electrode 2021 and the center line T2 of the second electrode 2021 on the corresponding first electrode plate 200, and similarly, the opposite two side edges of the third electrode 3012 respectively coincide with the center line T1 of the first electrode 2012 and the center line T2 of the second electrode 2022 on the corresponding third electrode plate 400.

[0209] As shown in the second electrode group and the fourth electrode group, Figure 24b the arrangement of the electrodes is the same as that of the first electrode group and the third electrode group, which will not be described here.

[0210] Then, the corresponding signal processing mode can include that the processor obtains C1 U- according to the difference formula C1 U- , obtains C1 D- according to the difference formula C1 D- ; and obtains C1 U+ according to the sum formula C1 U+ , obtains C1 D+ according to the sum formula C1 D+ ; and the processor further obtains C1 - according to C1 U- +C1 D- and C1 + =C1 U+ -C1 D+, the magnitude of the spatial external force F borne by the force sensor is calculated.

[0211] In one embodiment, when Figure 5 and Figure 6 The electrodes on the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400 are shown as Figure 25a and Figure 25b When there are eight sets of electrode groups, and the eight sets of electrode groups are equidistantly arranged along the circumferences of the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400, eight differential signals C1 - to C8 - and eight sum signals C1 + to C8 + The spatial six-dimensional force can be represented as wherein, A is a constant matrix,

[0212] In this way, the force sensor comprising the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400, due to the addition of the third electrode plate 400, the area variation is larger, thereby doubling the sensitivity of the area variation type capacitors; in addition, this structure also increases the differential form of the pitch variation type capacitors, and also doubles the sensitivity of the pitch variation type capacitors.

[0213] As Figure 25a and Figure 25b Another arrangement of the electrodes in the first electrode group, the second electrode group, the third electrode group and the fourth electrode group is given. Specifically, see Figure 25b In the first electrode group and the third electrode group, the first side of the opposite two side edges of the third electrode on the second electrode plate 300 coincides with the center line T1 of the first electrode, and the second side coincides with the center line T2 of the second electrode. For example, in the first electrode group, the opposite two side edges of the third electrode 3011 coincide with the center line T1 of the first electrode 2011 and the center line T2 of the second electrode 2021 on the corresponding first electrode plate 200, and similarly, the opposite two side edges of the third electrode 3012 coincide with the center line T1 of the first electrode 2012 and the center line T2 of the second electrode 2022 on the corresponding third electrode plate 400; in the third electrode group, the opposite two side edges of the third electrode 3021 coincide with the center line T1 of the first electrode 2021 and the center line T2 of the second electrode 2021 on the corresponding first electrode plate 200, and similarly, the opposite two side edges of the third electrode 3012 coincide with the center line T1 of the first electrode 2012 and the center line T2 of the second electrode 2022 on the corresponding third electrode plate 400.

[0214] However, see Figure 25aIn the second and fourth electrode groups, the first side edge of the third electrode on the normal projection of the first electrode plate 200 coincides with the center line of the interval between the first and second electrodes. For example, in the second electrode group, one side edge of the third electrode 3021 coincides with the center line T3 of the interval between the first electrode 2031 and the second electrode 2041 on the corresponding first electrode plate 200, and the other side edge of the third electrode 3021 coincides with the center line T4 of the interval between the first electrode 2031 and the second electrode 2041 on the corresponding first electrode plate 200; similarly, in the fourth electrode group, one side edge of the third electrode 3022 coincides with the center line T3 of the interval between the first electrode 2032 and the second electrode 2042 on the corresponding third electrode plate 400, and the other side edge of the third electrode 3022 coincides with the center line T4 of the interval between the first electrode 2032 and the second electrode 2042 on the corresponding first electrode plate 200. Figure 25b In the second and fourth electrode groups, the first side edge of the third electrode on the normal projection of the first electrode plate 200 coincides with the center line of the interval between the first and second electrodes. For example, in the second electrode group, one side edge of the third electrode 3021 coincides with the center line T3 of the interval between the first electrode 2031 and the second electrode 2041 on the corresponding first electrode plate 200, and the other side edge of the third electrode 3021 coincides with the center line T4 of the interval between the first electrode 2031 and the second electrode 2041 on the corresponding first electrode plate 200; similarly, in the fourth electrode group, one side edge of the third electrode 3022 coincides with the center line T3 of the interval between the first electrode 2032 and the second electrode 2042 on the corresponding third electrode plate 400, and the other side edge of the third electrode 3022 coincides with the center line T4 of the interval between the first electrode 2032 and the second electrode 2042 on the corresponding first electrode plate 200.

[0215] Further, the corresponding signal processing method can include that the processor obtains C1 U- according to the difference formula C1 U- , obtains C1 D- according to the difference formula C1 D- ; and then calculates the size of the spatial external force F borne by the force sensor according to C1 - = C1 U- + C1 D- .

[0216] In an embodiment, when Figure 5 and Figure 6 the electrodes on the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400 are as shown in ​ and ​ , eight groups of electrode groups are provided, and the eight groups of electrode groups are equally spaced along the circumferences of the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400, eight difference signals C1 - to C8 - can be obtained, and the spatial six-dimensional force can be represented as wherein, A is a constant matrix,

[0217] and the above-mentioned effects including the electrode arrangement in the first electrode plate 200, the second electrode plate 300 and the third electrode plate 400 are similar, which doubles the sensitivity of the area change type capacitor and increases the differential form of the interval change type capacitor, so that the sensitivity of the interval change type capacitor is doubled.

[0218] In the description of the present specification, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in an appropriate manner.

[0219] The above description is merely illustrative of the application and is not intended to limit the scope of the application. Any changes or modifications that can be made to the application in accordance with the principles of the application should also be included within the scope of the application. Therefore, the scope of the application should be determined by the scope of the claims.

Claims

1. A capacitive force sensor, characterized by The capacitor force sensor comprises: a first electrode plate; a second electrode plate, which is arranged opposite to the first electrode plate and has a spacing between the first electrode plate and the second electrode plate, one of the first electrode plate and the second electrode plate is a fixed electrode plate, and the other is a movable electrode plate; an elastic body, which is fixedly connected to the movable electrode plate, and can drive the movable electrode plate to move relative to the fixed electrode plate along a direction parallel to the fixed electrode plate and a direction perpendicular to the fixed electrode plate, and can drive the movable electrode plate to rotate relative to the fixed electrode plate along an axis parallel to the fixed electrode plate and an axis perpendicular to the fixed electrode plate; at least one electrode group, any electrode group comprising: a plurality of first electrodes electrically connected to each other, a plurality of second electrodes electrically connected to each other, and a plurality of third electrodes electrically connected to each other; a plurality of first electrodes and a plurality of second electrodes are arranged on a surface of the first electrode plate opposite to the second electrode plate, and the plurality of first electrodes and the plurality of second electrodes are arranged alternately; a plurality of third electrodes are arranged on a surface of the second electrode plate opposite to the first electrode plate; the first electrodes, the third electrodes and the second electrodes are arranged in a staggered manner, any third electrode and its adjacent first electrode and second electrode form a coupling structure, and any first electrode and any second electrode belong to an independent coupling structure, when the movable electrode plate moves relative to the fixed electrode plate, the plurality of first electrodes and the plurality of third electrodes form a first capacitor, and the plurality of second electrodes and the plurality of third electrodes form a second capacitor.

2. The capacitive force sensor of claim 1, wherein, In the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the width of any first electrode and any second electrode is W1, the width of each adjacent first electrode and second electrode is W2, and the width of any third electrode is W, and the width between each adjacent two third electrodes is W, wherein W=W1+W2.

3. The capacitive force sensor according to claim 1 or 2, characterized in that The at least one electrode group comprises a first electrode group; In the first electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged in a straight line along a first direction parallel to the first electrode plate; or, In the first electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged in an arc shape along the circumference of the first electrode plate.

4. The capacitive force sensor of claim 3, wherein, The orthographic projection of the first electrodes and the second electrodes on the second electrode plate covers the third electrodes in a direction perpendicular to the arrangement direction of the plurality of first electrodes and the plurality of second electrodes; or, The orthographic projection of the third electrodes on the first electrode plate covers the first electrodes and the second electrodes in a direction perpendicular to the arrangement direction of the plurality of first electrodes and the plurality of second electrodes.

5. The capacitive force sensor of claim 3, wherein, The at least one electrode group further comprises a second electrode group; The plurality of first electrodes and the plurality of second electrodes in the first electrode group are arranged on both sides of the center of the first electrode plate together with the plurality of first electrodes and the plurality of second electrodes in the second electrode group.

6. The capacitor force sensor according to claim 5, wherein In any of the first electrode group and the second electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the first electrode; Wherein, the center line of the first electrode is the center line of the first electrode along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes.

7. The capacitive force sensor of claim 6, wherein, The capacitive force sensor further comprises a processor; The processor obtains C1 according to the difference formula C1 - =C1-C2 - , obtains C2 according to the difference formula C2 - =C3-C4 - ; And , C1 is obtained according to the summation formula C1 + = C1 + C2 + , C2 is obtained according to the summation formula C2 + = C3 + C4 + ; The processor also calculates the external force F borne by the capacitive force sensor according to C1 - , C2 - , C1 + and C2 + . Wherein, C1 is the capacitance value output by the first capacitor in the first electrode group; C2 is the capacitance value output by the second capacitor in the first electrode group; C3 is the capacitance value output by the first capacitor in the second electrode group; C4 is the capacitance value output by the second capacitor in the second electrode group.

8. The capacitive force sensor according to claim 5, wherein, In the first electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the first electrode; In the second electrode group, along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the gap between the first electrode and the second electrode. Wherein, the center line of the first electrode is the center line of the first electrode along the arrangement direction of the plurality of first electrodes and the plurality of second electrodes.

9. The capacitive force sensor of claim 8, wherein, The capacitive force sensor further comprises a processor; The processor obtains C1 according to the difference formula C1 - = C1 - C2 - , and obtains C2 according to the difference formula C2 - = C3 - C4 - ; The processor also calculates the external force F borne by the capacitive force sensor according to C1 - and C2 - . Wherein, C1 is the capacitance value output by the first capacitor in the first electrode group; C2 is the capacitance value output by the second capacitor in the first electrode group; C3 is the capacitance value output by the first capacitor in the second electrode group; C4 is the capacitance value output by the second capacitor in the second electrode group.

10. The capacitive force sensor of claim 6, wherein, The capacitive force sensor further comprises: A third electrode plate, the third electrode plate is arranged on the side of the second electrode plate away from the first electrode plate; The at least one electrode group further comprises a third electrode group; In the third electrode group, the plurality of first electrodes and the plurality of second electrodes are arranged on the surface of the third electrode plate opposite to the second electrode plate, and the plurality of third electrodes are arranged on the surface of the second electrode plate opposite to the third electrode plate; The third electrode group and the first electrode group are symmetrically arranged about the second electrode plate.

11. The capacitive force sensor of claim 10, wherein, The capacitive force sensor further comprises a processor; The processor obtains C1 according to the difference formula C1 U- = C1 - C2 U- , obtains C1 according to the difference formula C1 D- = C5 - C6 D- ; and C1 is obtained from the summation formula C1 U+ = C1 + C2 U+ , and C1 is obtained from the summation formula C1 D+ = C5 + C6 D+ ; The processor also calculates the external force F borne by the capacitive force sensor according to C1 - = C1 U- + C1 D- and C1 + = C1 U+ - C1 D+ , Wherein, C1 is the capacitance value output by the first capacitor in the first electrode group; C2 is the capacitance value output by the second capacitor in the first electrode group; C5 is the capacitance value output by the first capacitor in the third electrode group; C6 is the capacitance value output by the second capacitor in the third electrode group.

12. The capacitive force sensor of claim 8, wherein, The capacitive force sensor further comprises: a third electrode plate disposed on a side of the second electrode plate facing away from the first electrode plate; the at least one electrode group further comprises a third electrode group; in the third electrode group, a plurality of the first electrodes and a plurality of the second electrodes are disposed on a surface of the third electrode plate opposite to the second electrode plate, and a plurality of the third electrodes are disposed on a surface of the second electrode plate opposite to the third electrode plate; the third electrode group and the first electrode group are symmetrically arranged about the second electrode plate.

13. The capacitive force sensor of claim 12, wherein, the capacitive force sensor further comprises a processor; The processor obtains C1 according to the difference formula C1 U- = C1 - C2 U- , obtains C1 according to the difference formula C1 D- = C5 - C6 D- ; The processor also calculates the external force F borne by the capacitive force sensor according to C1 - = C1 U- + C1 D- , C1 is a capacitance value output by the first capacitor in the first electrode group; C2 is a capacitance value output by the second capacitor in the first electrode group; C5 is a capacitance value output by the first capacitor in the third electrode group; C6 is a capacitance value output by the second capacitor in the third electrode group.

14. The capacitive force sensor of claim 3, wherein, the at least one electrode group further comprises a fifth electrode group; in the fifth electrode group, a plurality of the first electrodes and a plurality of the second electrodes are arranged on a surface of the first electrode plate opposite to the second electrode plate along a second direction, and a plurality of the third electrodes are disposed on a surface of the second electrode plate opposite to the third electrode plate; the second direction is perpendicular to the first direction.

15. The capacitive force sensor according to claim 1 or 2, characterized in that eight electrode groups are disposed on the first electrode plate and the second electrode plate opposite to each other, and the eight electrode groups are equally spaced along a circumferential direction of the first electrode plate and the second electrode plate.

16. The capacitive force sensor according to claim 1 or 2, characterized in that the capacitive force sensor further comprises: a main body, a receiving cavity is formed in the main body; the elastic body is disposed in the receiving cavity, the elastic body comprises a connecting portion and a plurality of elastic arms arranged along a circumferential direction of the connecting portion, and an end of the elastic arm away from the connecting portion is fixedly connected with the main body; the first electrode plate and the second electrode plate are both disposed in the receiving cavity, the second electrode plate is disposed opposite to the elastic body and is fixedly connected with the connecting portion, and the first electrode plate is disposed on a side of the second electrode plate facing away from the elastic body and is fixedly connected with the main body; the capacitive force sensor further comprises a force receiving plate, the force receiving plate is disposed outside the receiving cavity and is fixedly connected with the second electrode plate.

17. A measurement method for detecting an external force received by a detection device using a capacitive force sensor mounted on the detection device, characterized by, the capacitive force sensor comprises: a first electrode plate; a second electrode plate disposed opposite to the first electrode plate, and the first electrode plate and the second electrode plate have a spacing therebetween, one of the first electrode plate and the second electrode plate is a fixed electrode plate, and the other is a movable electrode plate; an elastic body fixedly connected with the movable electrode plate, the elastic body can drive the movable electrode plate to move relative to the fixed electrode plate along a direction parallel to the fixed electrode plate and a direction perpendicular to the fixed electrode plate, and can drive the movable electrode plate to rotate relative to the fixed electrode plate along an axis parallel to the fixed electrode plate and an axis perpendicular to the fixed electrode plate; at least one electrode group, any electrode group comprises: a plurality of first electrodes electrically connected with each other, a plurality of second electrodes electrically connected with each other, and a plurality of third electrodes electrically connected with each other; A plurality of the first electrodes and a plurality of the second electrodes are arranged on the surface of the first electrode plate opposite to the second electrode plate, and the plurality of the first electrodes and the plurality of the second electrodes are arranged alternately; A plurality of the third electrodes are arranged on the surface of the second electrode plate opposite to the first electrode plate; The first electrodes, the third electrodes and the second electrodes are arranged staggeredly, any third electrode and its adjacent first electrode and second electrode form a coupling structure, and any first electrode and any second electrode belong to an independent coupling structure, when the moving electrode plate moves relative to the fixed electrode plate, a plurality of the first electrodes and a plurality of the third electrodes form a first capacitor, and a plurality of the second electrodes and a plurality of the third electrodes form a second capacitor; The measurement method comprises: Collecting the capacitance value of the first capacitor and collecting the capacitance value of the second capacitor; According to the capacitance value of the first capacitor and the capacitance value of the second capacitor, the external force F borne by the detection device is measured.

18. The method of measuring according to claim 17, wherein, The width of any first electrode and any second electrode along the arrangement direction of the plurality of the first electrodes and the plurality of the second electrodes is W1, the width of each adjacent first electrode and second electrode is W2, and the width of any third electrode is W, and the width between each adjacent two third electrodes is W, wherein W=W1+W2; The at least one electrode group comprises a first electrode group and a second electrode group, and the plurality of the first electrodes and the plurality of the second electrodes in the first electrode group are arranged on both sides of the center of the first electrode plate, and the plurality of the first electrodes and the plurality of the second electrodes in the second electrode group are arranged on both sides of the center of the first electrode plate. Collecting the capacitance value of the first capacitor and collecting the capacitance value of the second capacitor comprises: Collecting the capacitance value C1 output by the first capacitor in the first electrode group, collecting the capacitance value C2 output by the second capacitor in the first electrode group, collecting the capacitance value C3 output by the first capacitor in the second electrode group, and collecting the capacitance value C4 output by the second capacitor in the first electrode group.

19. The measurement method according to claim 18, wherein In any electrode group of the first electrode group and the second electrode group, along the arrangement direction of the plurality of the first electrodes and the plurality of the second electrodes, the third electrode comprises opposite first and second side edges, and the orthogonal projection of the first side edge on the first electrode plate coincides with the center line of the first electrode. Using the capacitance value of the first capacitor and the capacitance value of the second capacitor, the external force F borne by the detection device is measured, comprising: According to the difference formula C1 - = C1 - C2 to obtain C1 - , according to the difference formula C2 - = C3 - C4 to obtain C2 - ; and, according to the sum formula C1 + = C1 + C2 to obtain C1 + , according to the sum formula C2 + = C3 + C4 to obtain C2 + ; According to C1 - , C2 - , C1 + and C2 + , the external force F experienced by the detection device is calculated.

20. The method of claim 18, wherein, The capacitive force sensor further comprises: A third electrode plate arranged on the side of the second electrode plate away from the first electrode plate; The at least one electrode group further comprises a third electrode group. In the third electrode group, a plurality of the first electrodes and a plurality of the second electrodes are arranged on a surface of the third electrode plate opposite to the second electrode plate, and a plurality of the third electrodes are arranged on a surface of the second electrode plate opposite to the third electrode plate; The third electrode group and the first electrode group are symmetrically arranged about the second electrode plate; In any one of the first electrode group and the second electrode group, along the arrangement direction of the plurality of the first electrodes and the plurality of the second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the first electrode; The method further comprises: Collecting a capacitance value C5 output by the first capacitor in the third electrode group and a capacitance value C6 output by the second capacitor in the third electrode group; Using the capacitance value of the first capacitor and the capacitance value of the second capacitor, the external force F borne by the detection device is measured, comprising: According to the difference formula C1 U- = C1 - C2 to obtain C1 U- , according to the difference formula C1 D- = C5 - C6 to obtain C1 D- ; and C1 is obtained from the summation formula C1 U+ = C1 + C2 U+ , and C1 is obtained from the summation formula C1 D+ = C5 + C6 D+ ; Again according to C1 - = C1 U- + C1 D- and C1 + = C1 U+ - C1 D+ , the external force F borne by the detection device is calculated.

21. The measurement method of claim 18, wherein, In the first electrode group, along the arrangement direction of the plurality of the first electrodes and the plurality of the second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the first electrode; In the second electrode group, along the arrangement direction of the plurality of the first electrodes and the plurality of the second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of a gap between the first electrode and the second electrode; Using the capacitance value of the first capacitor and the capacitance value of the second capacitor, the external force F borne by the detection device is measured, comprising: According to the difference formula C1 - = C1 - C2 - and according to the difference formula C2 - = C3 - C4 - ; According to C1 - and C2 - , the external force F borne by the detection device is calculated.

22. The method of measuring of claim 18, wherein, The capacitive force sensor further comprises: A third electrode plate arranged on a side of the second electrode plate away from the first electrode plate; The at least one electrode group further comprises a third electrode group; In the third electrode group, a plurality of the first electrodes and a plurality of the second electrodes are arranged on a surface of the third electrode plate opposite to the second electrode plate, and a plurality of the third electrodes are arranged on a surface of the second electrode plate opposite to the third electrode plate; The third electrode group and the first electrode group are symmetrically arranged about the second electrode plate; In the first electrode group, along the arrangement direction of the plurality of the first electrodes and the plurality of the second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of the first electrode; In the second electrode group, along the arrangement direction of the plurality of the first electrodes and the plurality of the second electrodes, the third electrode comprises opposite first and second side edges, and a projection of the first side edge on the first electrode plate coincides with a center line of a gap between the first electrode and the second electrode; The method for collecting the capacitance value of the first capacitor and the capacitance value of the second capacitor further comprises: The method further comprises collecting the capacitance value C5 output by the first capacitor in the third electrode group and collecting the capacitance value C6 output by the second capacitor in the third electrode group; The method for measuring the external force F borne by the detection device by using the capacitance value of the first capacitor and the capacitance value of the second capacitor comprises: According to the difference formula C1 U- = C1 - C2 to obtain C1 U- , according to the difference formula C1 D- = C5 - C6 to obtain C1 D- ; Again according to C1 - = C1 U- + C1 D- , the external force F borne by the detection device is calculated.

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