A flexible bending sensor

Abstract

The present invention relates to a flexible bending sensor, and to the field of flexible electronic technology, in order to solve the technical problem that the existing bending sensor cannot accurately measure the bending angle information of a soft robotic arm. The flexible bending sensor described in the present invention comprises a first elastomer and a second elastomer, the two ends of the first elastomer are respectively connected to the two ends of the second elastomer, and a cavity is formed between the first elastomer and the second elastomer, the inner curved surface of the first elastomer is attached with a double-sided flexible circuit board, and the inner curved surface of the second elastomer is attached with a copper foil attachment layer, when the joint to be measured is bent, the double-sided flexible circuit board and the copper foil attachment layer are attached to each other, and the bending angle of the joint to be measured is determined according to the attachment area, thereby realizing the measurement of the bending angle of the soft robotic arm.

Description

Technical Field

[0001] The present invention relates to the field of flexible electronic technology, and in particular to a flexible bending sensor for detecting the bending state of a soft arm. Background Art

[0002] Traditional commercial bending sensors mainly use PET sheets or polyimide sheets as substrates. When the joint to be measured is bent, the joint bending is measured based on the change in the resistivity of the sensor surface material. However, traditional bending sensors have no elasticity and cannot adapt to the surface stretching effect caused by joint bending. They can only be used to measure surface joints without elastic deformation. Soft robotic arms usually use elastic soft materials such as silicone as the outer structure, and their bending process is usually accompanied by elastic deformation, such as elastic elongation of the outer surface of the bend. Therefore, traditional bending sensors cannot be used to measure soft robotic arms. Based on this, there is an urgent need for a bending sensor that can accurately measure soft robotic arms. Summary of the invention

[0003] The object of the present invention is to provide a flexible bending sensor for measuring the bending angle information of a soft robotic arm.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A flexible bending sensor, the sensor comprising a first elastomer and a second elastomer, the two ends of the first elastomer being respectively connected to the two ends of the second elastomer, a cavity being formed between the first elastomer and the second elastomer, the first elastomer being attached to the extensible and bendable surface of a joint to be measured, with the cavity as the interior, a double-sided flexible circuit board being attached to the inner curved surface of the first elastomer, and a copper foil attachment layer being attached to the inner curved surface of the second elastomer, in a natural state, a gap is left between the double-sided flexible circuit board and the copper foil attachment layer; when the joint to be measured is bent, the double-sided flexible circuit board and the copper foil attachment layer are attached to each other, and the double-sided flexible circuit board is used to determine the bending angle of the joint to be measured according to the attachment area.

[0006] The present invention also provides a multi-joint bending angle measuring device, which is composed of a plurality of the flexible bending sensors, which are respectively attached to different joints to be measured. The plurality of flexible bending sensors are connected in parallel to form a total circuit, and the number of bits of the capacitance value of the total circuit is the same as the number of the flexible bending sensors, and each bit of the capacitance value represents the bending angle of a joint to be measured.

[0007] The present invention also provides a method for measuring a joint bending angle using a flexible bending sensor, the method comprising:

[0008] Obtain the capacitance value between the two measuring ends when the joint to be tested is bent;

[0009] The bending angle of the joint to be measured is calculated according to the capacitance value.

[0010] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0011] The flexible bending sensor provided by the present invention includes a first elastomer and a second elastomer, wherein two ends of the first elastomer are respectively connected to two ends of the second elastomer, and a cavity is formed between the first elastomer and the second elastomer, a double-sided flexible circuit board is attached to the inner curved surface of the first elastomer, and a copper foil attachment layer is attached to the inner curved surface of the second elastomer. When the joint to be measured bends, the first elastomer and the second elastomer bend with the joint to be measured, thereby driving the double-sided flexible circuit board on the inner curved surface of the first elastomer and the copper foil attachment layer on the inner curved surface of the second elastomer to gradually fit together. A plurality of metal copper sheets are arranged on the inner surface of the double-sided flexible circuit board, and the plurality of metal copper sheets are arranged in parallel and at intervals between the two ends of the first elastic body. Therefore, the gradual bonding of the double-sided flexible circuit board and the copper foil attachment layer is reflected in that the plurality of metal copper sheets on the double-sided flexible circuit board are gradually bonded to the copper foil attachment layer. A plurality of fixed-value patch capacitors are arranged on the outer surface of the double-sided flexible circuit board, and each fixed-value patch capacitor corresponds to a metal copper sheet, and each of the metal copper sheets is connected to an electrode of the corresponding fixed-value patch capacitor. Therefore, when the copper foil attachment layer is bonded to the metal copper sheet, the fixed-value patch capacitor corresponding to the metal copper sheet is connected to the copper foil attachment layer, and the other electrodes of the plurality of fixed-value patch capacitors are connected in series and connected to the first measuring end of the sensor, and the copper foil attachment layer is connected to the second measuring end. By measuring the capacitance values ​​of the two measuring ends, the number of fixed-value patch capacitors connected to the circuit can be known, and the number of bonded metal copper sheets is determined according to the number of fixed-value patch capacitors, and then the bonding area is calculated according to the number of metal copper sheets, and finally the bending angle of the joint to be measured is determined.

[0012] The flexible bending sensor provided by the present invention has the advantages of a large adjustment range of sensitivity and range and strong adaptability. When the number of metal copper sheets or fixed-value chip capacitors in the double-sided flexible circuit board is changed, or the curvature of the first elastomer and the second elastomer is changed, the fitting area changes with the bending angle information of the joint to be measured.

[0013] The multi-joint bending angle measuring device provided by the present invention is achieved by attaching multiple flexible bending sensors to different joints to be measured respectively, and connecting the multiple flexible bending sensors in parallel to form a total circuit, setting the number of bits of the capacitance value of the total circuit to be the same as the number of flexible bending sensors, and each bit of the capacitance value represents the bending angle of a joint to be measured, so that the bending angle information of each joint to be measured is obtained according to the capacitance value of the total circuit, thereby realizing dual-lead multi-joint measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 A schematic diagram of the overall structure of the flexible bending sensor provided in Example 1 of the present invention;

[0016] Figure 2 A side view of the overall structure of the flexible bending sensor provided in Example 1 of the present invention;

[0017] Figure 3 A schematic diagram of the inner surface structure of a double-sided flexible circuit board provided in Example 1 of the present invention;

[0018] Figure 4 A schematic diagram of the outer surface structure of a double-sided flexible circuit board provided in Example 1 of the present invention;

[0019] Figure 5 A schematic diagram of the arrangement of the metal copper sheets on the double-sided flexible circuit board provided in Example 1 of the present invention;

[0020] Figure 6 A schematic diagram of multi-joint bending angle measurement provided in Example 2 of the present invention;

[0021] Figure 7 This is a schematic diagram of a multi-joint measurement circuit provided in Example 2 of the present invention.

[0022] Explanation of symbols:

[0023] 1: first elastic body; 2: second elastic body; 3: double-sided flexible circuit board; 4: copper foil attachment layer; 5 metal copper sheet; 6: fixed value chip capacitor; 7: via; 8: first measuring end; 9: second measuring end; 10: joint to be measured. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The objective of the present invention is to provide a flexible bending sensor. By setting a first elastomer attached to a double-sided flexible circuit board and a second elastomer attached to a copper foil attaching layer, the double-sided flexible circuit board and the copper foil attaching layer are gradually attached to each other as the joint to be measured is bent. The bending angle of the joint to be measured is obtained through the attachment area, thereby realizing the measurement of the bending angle information of the soft robotic arm.

[0026] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] This embodiment provides a flexible bending sensor. Figure 1 The sensor includes a first elastic body 1 and a second elastic body 2. The two ends of the first elastic body 1 are respectively connected to the two ends of the second elastic body 2, and a cavity is formed between the first elastic body 1 and the second elastic body 2. The first elastic body 1 is attached to the ductile and bendable surface of the joint 10 to be measured. With the cavity as the inside, the inner curved surface of the first elastic body 1 is attached with a double-sided flexible circuit board 3, and the inner curved surface of the second elastic body 2 is attached with a copper foil attachment layer 4. In the natural state, a gap is left between the double-sided flexible circuit board 3 and the copper foil attachment layer 4. For details, please refer to Figure 2 When the joint to be tested 10 is bent, the double-sided flexible circuit board 3 and the copper foil attachment layer 4 are bonded to each other, and the bending angle information of the joint to be tested 10 is calculated according to the correspondence between the bonding area and the bending angle defined in advance.

[0029] Based on the flexible bending sensor described in this embodiment, it is used to measure the bending angle information of the soft robotic arm. Therefore, when the joint 10 to be measured is bent, in order to enable the sensor to bend along with the joint 10 to be measured, the structural body of the sensor is set to be made of silicone material, that is, the first elastomer 1 and the second elastomer 2 are made of silicone material. Based on the high flexibility of the silicone material, the sensor made of silicone material can bend gradually along with the bending of the joint 10 to be measured. Specifically, the first elastomer 1 and the second elastomer 2 can be prepared by the following method: first, the liquid silicone is stirred in a vacuum container to remove bubbles, and then poured into a mold for curing. The silicone mold is made of photosensitive resin material by 3D printing, so that the preparation cost of the flexible bending sensor is low.

[0030] As an optional embodiment, the two ends of the first elastomer 1 are respectively bonded and fixed to the two ends of the second elastomer 2 by thixotropic single-component organic silicone. As a silicone adhesive, thixotropic single-component organic silicone can achieve the bonding of silicone with other materials, and it still has elasticity after curing. Therefore, thixotropic single-component organic silicone is used to bond and fix the two ends of the first elastomer 1 and the second elastomer 2, so that when the joint 10 to be tested is restored from the bent state to the initial state, the thixotropic single-component organic silicone can follow the first elastomer 1 and the second elastomer 2 to restore to the original state, so as not to be irreversible after deformation.

[0031] Regarding the calculation of the bonding area between the double-sided flexible circuit board 3 and the copper foil bonding layer 4 when the joint 10 to be tested is bent, this embodiment provides an optional implementation method, please refer to Figure 3 The inner surface of the double-sided flexible circuit board 3 is provided with a plurality of metal copper sheets 5, and the plurality of metal copper sheets 5 are arranged in parallel and at intervals between the two ends of the first elastic body 1. Since a plurality of metal copper sheets 5 are arranged on the double-sided flexible circuit board 3, the process of gradual bonding between the double-sided flexible circuit board 3 and the copper foil attachment layer 4 is reflected as the gradual bonding between the plurality of metal copper sheets 5 and the copper foil attachment layer 4, and the bonding area is determined by the bonding number of the copper foil attachment layer 4 and the metal copper sheets 5, and the greater the bending angle of the joint 10 to be measured, the greater the bonding number of the copper foil attachment layer 4 and the metal copper sheets 5, and the larger the bonding area.

[0032] The outer surface of the double-sided flexible circuit board 3 is provided with a plurality of fixed value chip capacitors 6, for details, please refer to Figure 4 Each fixed-value patch capacitor 6 corresponds to a metal copper sheet 5, each metal copper sheet 5 is connected to an electrode of the corresponding fixed-value patch capacitor 6, and the other electrodes of multiple fixed-value patch capacitors 6 are connected in series and connected to the first measuring end 8 of the sensor; the copper foil attachment layer 4 is connected to the second measuring end 9, and the bonding area is determined according to the capacitance value between the first measuring end 8 and the second measuring end 9.

[0033] Specifically, as the joint 10 to be measured gradually bends, the copper foil attachment layer 4 gradually fits with the multiple metal copper sheets 5 located on the inner surface of the double-sided flexible circuit board 3, and each metal copper sheet 5 is connected to a fixed-value chip capacitor 6. Therefore, in the process of the copper foil attachment layer 4 gradually fitting with the multiple metal copper sheets 5, fixed-value chip capacitors 6 are continuously connected to the circuit, and there are as many fixed-value chip capacitors 6 connected to the circuit as there are metal copper sheets 5 fitting with the copper foil attachment layer 4. At the same time, since the other electrodes of the multiple fixed-value chip capacitors 6 are connected in series and connected to the first measuring end 8 of the sensor, and the copper foil attachment layer 4 is connected to the other measuring end, the number of fixed-value chip capacitors 6 connected to the circuit can be obtained by measuring the capacitance values ​​of the two measuring ends, and then the number of metal copper sheets 5 fitting with the copper foil attachment layer 4 can be known, and the fitting area can be obtained according to the number of metal copper sheets 5 fitting with the copper foil attachment layer 4. The bending angle information of the joint 10 to be measured is obtained through the corresponding relationship between the fitting area and the bending angle, thereby realizing the measurement of the bending angle of the soft joint.

[0034] As an optional embodiment, in order to distinguish the bonding area, the distances from any metal copper sheet 5 to the center end faces between the two ends of the first elastic body 1 are different. In order to enable those skilled in the art to more clearly understand the arrangement of multiple metal copper sheets 5 in the double-sided flexible circuit board 3 in this embodiment, and how to distinguish the bonding area according to the arrangement, the following is combined with the attached Figure 5 Provide explanation.

[0035] See also Figure 5 The dark dotted lines in the figure are the central end faces of the starting and ending ends. The multiple small rectangles in the figure represent multiple metal copper sheets 5, where the distances from the multiple metal copper sheets 5 labeled (1)-(N) to the central end faces are l1, l2..., l N , and l1≠l2≠...≠l N In this embodiment, l1<l2<...<l N It should be noted that here l1<l2<...<l NThis is only one case listed in the present embodiment, mainly to specifically illustrate the order of bonding between the metal copper sheet 5 and the copper foil attachment layer 4 when the joint 10 to be tested is bent. The present invention does not specifically limit the size relationship of the distance between each metal copper sheet 5 and the center end face, as long as the distance between any metal copper sheet 5 and the center end face is different. Since the distance between any metal copper sheet 5 and the center end face is different, when the joint 10 to be tested is gradually bent, the metal copper sheet 5 (1) closest to the center end face is first bonded to the copper foil attachment layer 4, followed by the metal copper sheet 5 (2), the metal copper sheet 5 (3), ..., the metal copper sheet 5 (N) and the copper foil attachment layer 4 (when the size relationship between the metal copper sheet 5 and the center end face changes, the bonding order also changes accordingly). Since each metal copper sheet 5 is connected to a fixed-value chip capacitor 6, the number of metal copper sheets 5 bonded to the copper foil attachment layer 4 is the number of fixed-value chip capacitors 6 connected to the circuit. Therefore, the capacitance value in the circuit is measured through the two measuring ends. By dividing the capacitance value by the capacitance of a fixed-value chip capacitor 6, the number of fixed-value chip capacitors 6 connected to the measurement circuit can be known, and then the number of metal copper sheets 5 bonded to the copper foil attachment layer 4 can be known. According to the number of metal copper sheets 5 bonded to the copper foil attachment layer 4, the last metal copper sheet 5 bonded to the copper foil attachment layer 4 can be obtained, and then the bonding area is calculated according to the distance between the last bonded metal copper sheet 5 and the central end face, and further according to the corresponding relationship between the bonding area and the bending angle, the bending angle information of the joint 10 to be measured is obtained, thereby realizing accurate measurement of the bending angle of the soft robotic arm.

[0036] As an optional embodiment, the double-sided flexible circuit board 3 further includes a plurality of vias 7, each via 7 corresponds to a fixed-value patch capacitor 6 and a metal copper sheet 5, and each interconnected fixed-value patch capacitor 6 and metal copper sheet 5 are connected through the corresponding via 7. For details, please refer to Figure 3 and Figure 4 .

[0037] The flexible bending sensor provided in this embodiment has the advantages of a large adjustment range of sensitivity and range and strong adaptability. When the number of metal copper sheets 5 or fixed-value chip capacitors 6 in the double-sided flexible circuit board 3 is changed, or the curvature of the first elastomer 1 and the second elastomer 2 is changed, the fitting area changes with the bending angle information of the joint 10 to be measured.

[0038] Example 2

[0039] This embodiment provides a multi-joint bending angle measuring device, which is composed of a plurality of flexible bending sensors described in Embodiment 1. Figure 6 , multiple flexible bending sensors are attached to different joints 10 to be tested, and multiple flexible bending sensors are connected in parallel through wires to form a total circuit. The schematic diagram of the circuit can be found in Figure 7In the circuit schematic, the connection between the metal copper sheet 5 and the copper foil attachment layer 4 on the double-sided flexible circuit board 3 is regarded as a switch. In order to obtain information of multiple measurement joints at the same time, fixed-value patch capacitors 6 with order of magnitude relationships are used in different sensor circuits. For example, the first measurement joint uses 4 1nf fixed-value capacitors, the second measurement joint uses 4 10nf fixed-value capacitors, and so on. The Nth measurement joint uses 4 10nf fixed-value capacitors. N-1 A fixed-value capacitor of nf is used. Since the circuits of each measuring joint are connected in parallel with each other, according to the principle of parallel addition of capacitors, the number of bits of the capacitance value of the total circuit of the multi-joint bending angle measuring device is the same as the number of flexible bending sensors, wherein each bit of the capacitance value represents the bending angle of a joint to be measured 10, thereby realizing dual-lead multi-joint measurement.

[0040] Example 3

[0041] This embodiment provides a method for measuring a joint bending angle using a flexible bending sensor. The flexible bending sensor used in this embodiment is the flexible bending sensor described in Embodiment 1 or Embodiment 2. The method includes:

[0042] Obtaining the capacitance value between the two measuring ends when the joint 10 to be tested is bent;

[0043] The bending angle of the joint 10 to be tested is calculated according to the capacitance value.

[0044] Specifically, a flexible bending sensor is set up using the scheme described in Example 1 and fixed to the extensible and bendable surface of the joint 10 to be tested. When the joint 10 to be tested is bent, the capacitance value between the two measuring ends is measured. For the specific method of calculating the bending angle of the joint 10 to be tested based on the capacitance value, refer to the method in the above Example 1.

[0045] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0046] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A flexible bending sensor, characterized in that: The sensor comprises a first elastomer and a second elastomer, two ends of the first elastomer are respectively connected to two ends of the second elastomer, a cavity is formed between the first elastomer and the second elastomer, the first elastomer is attached to the extensible and bendable surface of the joint to be measured, and the inner curved surface of the first elastomer is attached with a double-sided flexible circuit board, and the inner curved surface of the second elastomer is attached with a copper foil attachment layer, and in a natural state, a gap is left between the double-sided flexible circuit board and the copper foil attachment layer; when the joint to be measured is bent, the double-sided flexible circuit board and the copper foil attachment layer are attached to each other, and the double-sided flexible circuit board is used to determine the bending angle of the joint to be measured according to the attachment area; The inner surface of the double-sided flexible circuit board is provided with a plurality of metal copper sheets, and the plurality of metal copper sheets are arranged in parallel and at intervals between the two ends of the first elastic body. When the joint to be tested is bent, the metal copper sheets are bonded to the copper foil bonding layer, and the bonding area is determined by the bonding number of the copper foil bonding layer and the metal copper sheets; The outer surface of the double-sided flexible circuit board is provided with a plurality of fixed-value patch capacitors, each of the fixed-value patch capacitors corresponds to a metal copper sheet, each of the metal copper sheets is connected to an electrode of the corresponding fixed-value patch capacitor, and the other electrodes of the plurality of fixed-value patch capacitors are connected in series and connected to the first measuring end of the sensor; the copper foil attachment layer is connected to the second measuring end, and the capacitance value between the first measuring end and the second measuring end is used to determine the bonding area.

2. The flexible bending sensor according to claim 1, characterized in that: The distances from any of the metal copper sheets to the central end surfaces between the two ends of the first elastic body are different.

3. The flexible bending sensor according to claim 1, characterized in that: The double-sided flexible circuit board also includes a plurality of vias, each of the vias corresponds to one of the fixed-value patch capacitors and one of the metal copper sheets, and each of the interconnected fixed-value patch capacitors and the metal copper sheets is connected via a corresponding via.

4. The flexible bending sensor according to claim 1, characterized in that: The sensitivity and range of the sensor are changed by changing the number of the metal copper sheets or the fixed-value chip capacitors in the double-sided flexible circuit board; or the sensitivity and range of the sensor are changed by changing the curvatures of the first elastic body and the second elastic body.

5. The flexible bending sensor according to claim 1, characterized in that: The two ends of the first elastomer are respectively connected to the two ends of the second elastomer through thixotropic single-component organic silicone.

6. The flexible bending sensor according to claim 1, characterized in that: The first elastic body and the second elastic body are made of silicone.

7. A multi-joint bending angle measuring device, the device comprising a plurality of flexible bending sensors as described in any one of claims 1-6, the plurality of flexible bending sensors being respectively attached to different joints to be measured, the plurality of flexible bending sensors being connected in parallel to form a total circuit, the number of bits of the capacitance value of the total circuit being the same as the number of the flexible bending sensors, and each bit of the capacitance value representing the bending angle of a joint to be measured.

8. A method for measuring joint bending angle using a flexible bending sensor, characterized in that: The method is implemented by using the multi-joint bending angle measuring device according to claim 7, and comprises: Obtain the capacitance value between the two measuring ends when the joint to be tested is bent; The bending angle of the joint to be measured is calculated according to the capacitance value.

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