CN218211721U - Flexible sensor - Google Patents
Flexible sensor Download PDFInfo
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- CN218211721U CN218211721U CN202221535407.0U CN202221535407U CN218211721U CN 218211721 U CN218211721 U CN 218211721U CN 202221535407 U CN202221535407 U CN 202221535407U CN 218211721 U CN218211721 U CN 218211721U
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Abstract
The utility model discloses a flexible sensor relates to sensor technical field, flexible sensor includes flexible basement and foil gage, and the foil gage is evenly embedded on the basal plane of flexible basement with circular array mode, and the output resistance of data acquisition circuit measurement foil gage changes the power/moment information in order to acquire contact department. The utility model discloses a design a new flexible sensor, it can closely laminate the contact surface, follows the contact curved surface of unevenness, realizes that the curved surface matches and aligns to be used for measuring the normal direction of contact curved surface.
Description
Technical Field
The utility model relates to a sensor technical field especially relates to a flexible sensor.
Background
At present, the present wall climbing robot can only climb the surface of plane or fixed curvature for the majority, and the research to the variable curvature curved surface of wall climbing robot is complied with is rare, mostly follows the curved surface through the structure passively and changes, for example, the wall climbing robot that adopts magnetism to adsorb can utilize the track structure to acquire the curved surface of certain degree and change the compliance ability. However, the passive consequent curved surface of the mechanism lacks the capability of prejudgment and active regulation and control and can be less in curvature variation range.
In addition, the touch sensor can obtain normal information of the contact curved surface by using a flexible touch sensor capable of sensing force/moment is a great research hotspot, but the flexible touch sensor researched by most researchers can only sense three-dimensional force information generally, how to realize six-dimensional force sensing of the flexible touch sensor, and further, the normal direction of the contact curved surface is obtained by calculating by using the information is a great research difficulty.
SUMMERY OF THE UTILITY MODEL
The utility model provides a flexible sensor to solve among the prior art contact pick-up and can't comply with the variable curvature curved surface, and to the technical problem of the real-time normal direction perception of contact curved surface.
In order to solve the problems, the utility model provides a flexible sensor, which comprises a flexible substrate and a strain gauge,
the strain gauges are uniformly distributed on the bottom plane of the flexible substrate in a circular array mode, and the adjacent strain gauges are in different postures, so that the response to the deformation of the flexible sensor in all directions is realized;
still include with foil gage electric connection's data acquisition circuit, when flexible sensor adsorbs when different curved surfaces, the foil gage is crooked along with the bending curvature of contact curved surface, and the resistance of foil gage changes, data acquisition circuit is used for measuring the resistance value R of flexible sensor's foil gage i 。
Preferably, the flexible substrate is formed by casting a flexible material, and the strain gauge is embedded in the flexible substrate.
Preferably, the flexible substrate is provided in a hemisphere shape, and the diameter of the hemisphere shape is 48-52mm.
Preferably, the number of the strain gauges is at least 6, and the height of the strain gauges from the hemispherical plane of the flexible substrate is 7-9mm.
Preferably, the flexible substrate is cast from Ecoflex material.
Compared with the prior art, the utility model have apparent advantage and beneficial effect, the concrete aspect that embodies is in following:
the flexible sensor is characterized in that the flexible substrate is used for closely attaching the contact surface, the embedded strain gauge is used for sensing six-dimensional force applied to the contact position, the embedded strain gauge has certain compliance capacity and can adapt to deformation of the flexible sensor when the flexible sensor is attached to a curved surface, force/moment information of the contact position is obtained by measuring the change of output resistance of the embedded strain gauge, and the sensed information is processed to obtain normal information of the contact position. When the flexible sensor adsorbs different curved surfaces, the strain gauge can be bent along with the bending curvature of the contact curved surface, and then the resistance of the strain gauge changes. The utility model provides a flexible sensor can comply with the contact curved surface of unevenness, and it can realize the real-time normal direction perception to the contact curved surface simultaneously, can be used to realize that the curved surface matches and aligns, complies with the variable curvature curved surface.
Drawings
FIG. 1 is a schematic diagram of a mold required in a flexible sensor manufacturing process according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a flexible six-dimensional force sensor with curved surface normal direction sensing capability according to an embodiment of the present invention;
fig. 3 is a schematic diagram of the force applied to the flexible sensor when the normal of the contact surface passes through the calculation process in the embodiment of the present invention.
Description of reference numerals:
1-a flexible substrate; 2-strain gauge.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.
As shown in fig. 1-3, the present invention provides a flexible sensor having sensing capability of normal direction of curved surface, the flexible sensor includes a flexible substrate 1, a strain gauge 2 and a data acquisition circuit, wherein:
the flexible substrate 1 is formed by casting a flexible material and is used for ensuring that the flexible sensor can passively conform to a contact surface and realizing close fit of the contact surface; meanwhile, the flexible material can also play a role in protecting the strain gauge 2.
The strain gauges 2 are vertically and uniformly embedded on the flexible substrate 1 in a circular array mode, and the adjacent strain gauges 2 are in different postures, so that the response to the deformation of the flexible sensor in all directions is realized.
The data acquisition circuit is electrically connected with the strain gauge 2, when the flexible sensor is adsorbed on different curved surfaces, the strain gauge 2 can be bent along with the bending curvature of the contact curved surface, the resistance of the strain gauge 2 changes, and the data acquisition circuit is used for measuring the resistance value R of the strain gauge 2 of the flexible sensor i 。
It should be further noted that, referring to fig. 1, before the flexible substrate 1 is cast, the strain gauge 2 is fixed at a corresponding position of the mold in a designed layout manner, and during the high-temperature solidification process of the flexible substrate 1 of the flexible sensor, the position of the strain gauge 2 is adjusted in time to ensure that the strain gauge is at an ideal position, so as to achieve the embedding of the strain gauge 2.
Specifically, in the embodiment of the present invention, the flexible substrate 1 is formed by casting a flexible material, and the strain gauge 2 is embedded in the flexible substrate 1.
Specifically, referring to fig. 1, in the embodiment of the present invention, the flexible substrate 1 is formed in a hemisphere shape, and the diameter of the hemisphere is 48-52mm. In the preferred embodiment of the present invention, the diameter of the hemisphere is 50mm.
From this, flexible sensor is the hemisphere form that the diameter equals 50mm, both can guarantee like this that the sensor closely laminates the contact surface of arbitrary shape, and the hemisphere can transmit the flexible sensor external force to embedded setting to right foil gage 2 again better, guarantees its perception flexible sensor's the atress deformation condition, and this size can be adjusted according to the practical application condition.
It is further noted that the material of the cast flexible substrate 1 includes, but is not limited to, ecoflex, which is a fossil-based biodegradable and compostable plastic, which is an important basic material for many biodegradable and bio-based plastics.
Referring to fig. 2, in an embodiment of the present invention, the strain gauges 2 are embedded on the flexible substrate 1 in a circular array manner, the number of the strain gauges 2 is at least 6, and the height of the strain gauge 2 from the hemispherical plane of the flexible substrate 1 is 7-9mm.
From this, flexible sensor contains 6 or above foil gages 2, as the best preferred mode of the embodiment of the utility model provides a, foil gage 2 chooses for BHF2K-3AA model to the realization is to the perception of six-dimensional power.
Additionally, among the embodiments of the utility model, about 8mm apart from the hemisphere plane of flexible basement 1 are strained to foil gage 2, and adjacent foil gage 2 is embedded in flexible basement 1 (the hemisphere plane of parallel or perpendicular to flexible basement 1) with different gestures to guarantee that flexible sensor can realize the response to the deformation that all directions atress leads to.
It should be noted that, in the flexible sensor designed in this embodiment, calibration needs to be performed before the flexible sensor is used, and the calibration process is as follows:
constructing a six-input six-output neural network model, wherein the neural network model takes the resistance change output by a strain gauge 2 of a flexible sensor as an input variable and takes the six-dimensional force borne by the center of the hemispherical bottom surface of a flexible substrate 1 of the flexible sensor as an output variable;
acquiring input and output data corresponding to resistance change output by at least 1000 groups of strain gauges 2 and six-dimensional force applied to the center of the bottom surface of a hemisphere of a flexible substrate 1 to form a calibration sample data set;
training a neural network model by using the calibration sample data set, and determining each parameter of the neural network to obtain a determined neural network model;
and establishing a corresponding mapping relation between the resistance change of the strain gauge 2 and six-dimensional force borne by the center of the hemispherical bottom surface of the flexible substrate 1 to finish calibration of the flexible sensor.
It should be noted that the utility model discloses a six input six output's neural network model is found among the embodiment of the utility model, the neural network model includes but is not limited to PSOBP neural network model, marks the back to flexible sensor through above-mentioned calibration method, through the resistance of the foil gage 2 of measuring gained flexible sensor, can utilize the neural network model prediction of training gained to obtain the six-dimensional force that flexible sensor hemisphere bottom surface center department received.
The embodiment of the utility model provides an in the middle of flexible sensor be used for measuring the normal direction of contact curved surface, the measurement process as follows:
when the flexible sensor is in contact with the curved surface and is stressed to deform, the resistance value R of the strain gauge of the flexible sensor is measured through the data acquisition circuit i ；
According to the six-dimensional force borne by the center of the hemispherical bottom surface of the flexible sensor and the resistance value R of the strain gauge i The function relationship is established between the two sensors, and six-dimensional force information received by the center of the hemispherical bottom surface of the flexible sensor is obtained through calculation;
and calculating to obtain the normal direction of the contact position of the contact curved surface by utilizing the measured six-dimensional force information.
The specific calculation process is as follows:
when the curvature radius of the contact curved surface is larger than that of the flexible sensor (radius R), the contact surface adopts a plane approximation (plane alpha when no force is applied) 1 After application of force, the plane moves to alpha 2 ) When the force is not applied, the contact point is P, and after the force is applied, the flexible sensor deforms, the contact point moves to the point H, wherein F can be decomposed into F x 、F y 、F z . Theta can be solved inversely by the following formula.
r H ＝Rsinθ-d t cosθ
Wherein, F z Is the resultant force exerted on the bottom surface of the hemisphere of the sensor in the normal direction, F r Is F x And F y Resultant force of (i.e. the resultant force on the horizontal plane, F) r Is r axis) r H Is the coordinate value of the point H on the r axis; theta is the normal direction of the contact surface and the included angle between the normal directions of the bottom surface of the hemisphere of the flexible sensor, d n For normal deformation of the flexible sensor along the contact surface (perpendicular to the plane alpha) 1 、α 2 )，d t Is tangentially deformed (parallel to the plane alpha) 1 、α 2 ) And E is the Young modulus of the flexible sensor.
And simulating the deformation conditions of the flexible sensor under different stresses by using finite element simulation.
In particular, by varying the degree of deformation d of the flexible sensor n And d t Different stress conditions are simulated, and 1000 groups of corresponding six-dimensional force borne by the center of the hemispherical bottom surface of the sensor and the coordinate r of the contact point H on the r axis are obtained H 。
The 1000 groups of data are used as a training sample data set, and are learned by utilizing a neural network, so that a relational expression can be obtained by fitting:
through finite element simulation and a neural network algorithm, fitting, utilizing six-dimensional force information at the center of the bottom surface of the hemisphere of the measured sensor to calculate and obtain the coordinate of the H point on the r axis:
r H ＝g(F x ，F y ，F z ，M x ，M y ，M z )＝Rsinθ-d t cosθ
in summary, the measured six-dimensional force information (converted to F) is utilized z 、F r And r H ) The contact surface normal direction can be calculated and the included angle theta between the hemisphere bottom surface normal direction of the flexible sensor can realize the measurement of the contact surface normal direction.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to fall within the scope of the present disclosure.
Claims (5)
1. Flexible sensor, characterized in that the flexible sensor comprises a flexible substrate (1) and a strain gauge (2),
the strain gauges (2) are uniformly embedded on the flexible substrate (1) in a circular array mode, and the adjacent strain gauges (2) are in different postures so as to realize response to deformation of the flexible sensor in all directions;
the flexible sensor is characterized by further comprising a data acquisition circuit electrically connected with the strain gauge (2), when the flexible sensor is adsorbed on different curved surfaces, the strain gauge (2) is bent along with the bending curvature of the contact curved surface, and the resistance of the strain gauge (2) is generatedA change, the data acquisition circuit being adapted to measure the resistance value R of the strain gauge (2) of the flexible sensor i 。
2. The flexible sensor according to claim 1, characterized in that the flexible substrate (1) is cast from a flexible material, the strain gauge (2) being embedded on the flexible substrate (1).
3. The flexible sensor according to claim 2, characterized in that the flexible substrate (1) is provided in the shape of a hemisphere with a diameter of 48-52mm.
4. The flexible sensor according to claim 1, characterized in that the number of strain gauges (2) is at least 6 and the height of the strain gauges (2) from the hemispherical plane of the flexible substrate (1) is 7-9mm.
5. The flexible sensor according to any one of claims 1-4, characterized in that the flexible substrate (1) is cast from Ecoflex material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221535407.0U CN218211721U (en) | 2022-06-17 | 2022-06-17 | Flexible sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221535407.0U CN218211721U (en) | 2022-06-17 | 2022-06-17 | Flexible sensor |
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| Publication Number | Publication Date |
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| CN218211721U true CN218211721U (en) | 2023-01-03 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202221535407.0U Active CN218211721U (en) | 2022-06-17 | 2022-06-17 | Flexible sensor |
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| CN (1) | CN218211721U (en) |
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- 2022-06-17 CN CN202221535407.0U patent/CN218211721U/en active Active
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