CN-121994121-A - Plant flexible wearable sensor and data correction method thereof

CN121994121ACN 121994121 ACN121994121 ACN 121994121ACN-121994121-A

Abstract

The application provides a plant flexible wearable sensor and a data correction method thereof, and relates to the technical field of agriculture. The data correction method comprises the steps of firstly parallelly packaging silk nanofibers, temperature sensing fibers and resistance reference fibers and connecting the silk nanofibers, the temperature sensing fibers and the resistance reference fibers in parallel in an elastic insulation protection layer to obtain flexible electrodes, wherein the stretching coefficients of the silk nanofibers, the temperature sensing fibers and the resistance reference fibers are similar, synchronous deformation of the three fibers under axial strain is guaranteed, the three fibers are not mutually contained, then voltage is applied to the flexible electrodes through a linear scanning volt-ampere mode, intrinsic resistances of the fibers are respectively obtained, then real-time temperature change in the packaging body is solved through the temperature sensing fibers, the resistance reference fibers are used as a reference for signal normalization, interference is eliminated, and finally real strain is calculated based on the normalized resistance after temperature compensation and converted into the diameter change quantity of plant stalks or fruit organs. The data correction method of the application realizes the high-precision, in-situ and anti-interference dynamic physiological deformation monitoring of plants.

Inventors

Zhang Xuxuan
CHI YI
Lv Chenze
XU PEI
LIU QINGJUN
WU WEI
LU ENQI
YANG SU
WU XINYANG
XU MIN

Assignees

中国计量大学

Dates

Publication Date: 20260508
Application Date: 20260402

Claims (10)

1. A method for correcting data of a plant flexible wearable sensor, the method comprising: (A) Providing a flexible electrode (1), wherein the flexible electrode (1) comprises silk nanofibers (11), temperature sensing fibers (12) and resistance reference fibers (13) which are connected in parallel, and the silk nanofibers, the temperature sensing fibers and the resistance reference fibers are embedded in parallel and jointly encapsulated in an elastic insulating protective layer (14); The Young modulus difference of the silk nanofiber (11), the temperature sensing fiber (12) and the resistance reference fiber (13) is less than or equal to 10%, and the relative standard deviation of the length variation of the silk nanofiber, the temperature sensing fiber and the resistance reference fiber is less than or equal to 5% within the axial strain range of 0-200%; (B) Under the linear scanning volt-ampere mode, synchronously applying linear variation voltages of-5V to +5V to three parallel fibers of the flexible electrode (1), wherein the scanning period is 20 seconds/round, and performing linear fitting on current-voltage data acquired by each round, and respectively calculating to obtain the following components: The real-time resistance value R s of the silk nanofiber (11); the real-time resistance value R t of the temperature sensing fiber (12); real-time resistance value R of resistance reference fiber (13) ; (C) Performing a double track normalization correction on the data obtained in step (B), comprising the steps of: s1, calculating real-time temperature change delta T of the microenvironment where the flexible electrode (1) is located based on the R t , the resistance R t0 of the temperature sensing fiber (12) at the reference temperature T0 and the temperature coefficient alpha t , wherein the specific formula is as follows: Wherein R t is the real-time resistance value of the temperature sensing fiber (12), R t0 is the reference resistance of the temperature sensing fiber (12) at the reference temperature T0, and alpha t is the temperature coefficient of the temperature sensing fiber (12); S2, R s 、R t is respectively combined with R Normalization processing is carried out, and the specific formula is as follows: Wherein R s 'is the resistance value of the normalized silk nanofiber (11), and R t ' is the resistance value of the normalized temperature sensing fiber (12); S3, calculating the real strain epsilon after temperature compensation based on the reference resistance R s0 ', the strain sensitivity coefficient g and the temperature coefficient alpha s of the normalized silk nanofiber (11) at the reference temperature T0 by the following specific formulas: Wherein R s 'is the resistance of the normalized silk nanofiber (11), the reference resistance R s0 ' of the normalized silk nanofiber (11), g is the strain sensitivity coefficient of the silk nanofiber (11), and alpha s is the temperature coefficient of the silk nanofiber (11); (D) According to the real strain epsilon, the diameter variation delta D of the plant stalk or fruit organ is obtained through conversion; The diameter change amount delta D=D 0 ×epsilon, wherein D 0 is the initial diameter of the target section of the plant stalk obtained by actual measurement of a non-contact optical calliper or vernier caliper before the flexible electrode (1) is installed.
2. The method for correcting data of a plant flexible wearable sensor according to claim 1, characterized in that the silk nanofibres (11) are stress-sensitive conductive fibres obtained by nanofibrillation treatment of regenerated silk fibroin; when the silk nanofiber (11) is stretched, the resistance value is monotonically and repeatedly linearly changed along with the axial strain, so that the diameter of a plant organ is detected.
3. The data correction method of the plant flexible wearable sensor according to claim 2, characterized in that the strain-resistance response of the silk nanofiber (11) has a linearity R2 not less than 0.995, and in an axial strain range of 0-200%, the resistance change rate and the strain are in a direct proportion relation, and the value range of the proportionality coefficient, namely the strain sensitivity coefficient g, is 50-350.
4. The method for correcting data of a plant flexible wearable sensor according to claim 1, characterized in that the temperature sensing fiber (12) is a stretchable conductive fiber with an achiral spiral configuration, the resistance value of the temperature sensing fiber (12) has a high sensitivity response to temperature change, and the stretching mechanical behavior of the temperature sensing fiber (12) is matched with the silk nanofiber (11).
5. The data correction method of the plant flexible wearable sensor according to claim 4, characterized in that the temperature sensing fiber (12) is prepared by wet spinning aramid nanofibers, dimethyl sulfoxide dispersion liquid and polyvinyl alcohol aqueous solution; In the wet spinning stock solution, the mass ratio of the aramid nanofiber to the dimethyl sulfoxide dispersion to the polyvinyl alcohol aqueous solution is 1.2 (1-1.7) to 1.
6. The method of data correction of a plant flexible wearable sensor according to claim 1, characterized in that the resistive reference fiber (13) is a liquid metal based stretchable conductive fiber with a coil spring configuration; the resistance reference fiber (13) has a resistance temperature coefficient of <5ppm/° C and a resistance change rate of <0.1% in a test range of-19 ℃ to 100 ℃.
7. The data correction method of a plant flexible wearable sensor according to claim 1, characterized in that the elastic insulating protective layer (14) is an integral packaging structure which wraps three parallel fibers of the silk nanofiber (11), the temperature sensing fiber (12) and the resistance reference fiber (13).
8. The method for correcting data of a plant flexible wearable sensor according to claim 7, characterized in that the elastic insulating protective layer (14) is made of polydimethylsiloxane or aliphatic-aromatic random copolyester material; The surfaces of the elastic insulating protective layer (14) and the surfaces of the silk nanofibers (11), the temperature sensing fibers (12) and the resistance reference fibers (13) are subjected to chemical coupling to form interface combination, so that three fibers and the elastic insulating protective layer (14) are synchronously stretched and do not slide relatively in the deformation process of plant stalks, and the spatial consistency of a temperature field and a strain field in the package is maintained.
9. The plant flexible wearable sensor is characterized by comprising a flexible electrode (1), a data processing module (2) and a fixer (15); the flexible electrode (1) is an annular flexible belt body, silk nanofibers (11), temperature sensing fibers (12) and resistance reference fibers (13) are sequentially arranged along the length direction, and are embedded in the same elastic insulating protective layer (14) in parallel to form a parallel circuit, wherein the elastic insulating protective layer (14) wraps the silk nanofibers (11), the temperature sensing fibers (12) and the resistance reference fibers (13), and two ends of the elastic insulating protective layer are respectively connected with connectors (23); The data processing module (2) is detachably connected with the connector (23) of the flexible electrode (1) through a data line (24); The two fixing devices (15) are arranged at the two side ends of the flexible electrode (1) and are of a plastic shell structure with built-in magnets, and the two fixing devices (15) are mutually buckled in a magnetic attraction mode so as to annularly fasten the flexible electrode (1) to a plant stalk target section.
10. The plant flexible wearable sensor according to claim 9, wherein the data processing module (2) is integrated with a potentiostatic device, a master control and data processing module (2), a wireless communication module and a USB Type-C interface (21).

Description

Plant flexible wearable sensor and data correction method thereof Technical Field The invention relates to the technical field of agriculture, in particular to a plant flexible wearable sensor and a data correction method thereof. Background The plant flexible wearable sensor can reflect the moisture state, nutrient absorption and growth vigor of organs such as plant stems, fruits and the like by monitoring the diameter change of the organs in real time, and provides basic physiological data support for agricultural automation and intelligent production. In the prior art, a stress sensing principle based on resistance change is often adopted, namely, a flexible electrode is wound on a plant stalk, and the change of the circumference and diameter of the stalk is inverted by utilizing the change of the resistance value of the flexible electrode in a stretching state. For example, CN106580256B discloses a flexible pressure sensor and a preparation method thereof, and CN120426856A, CN120252861A, CN120258480A, CN114963955A and the like relate to a plant growth or physiological state monitoring system and method based on a flexible wearable strain sensor. However, flexible stress sensors with resistance variation as a core face significant accuracy bottlenecks in practical agricultural applications. One of the main error sources is temperature influence, namely that the resistance of common flexible sensing materials such as fibroin-based, carbon nano tube-based or conductive polymer-based has obvious temperature dependence, the day-night temperature difference of agricultural production environments is large, the plant surface microenvironment is influenced by transpiration, and the temperature deviation of the temperature deviation from the temperature measured by temperature sensors in the whole environment or in space discrete arrangement of a greenhouse is 1-2 ℃. The prior art generally performs temperature compensation on the resistance signal by additionally arranging an environmental temperature sensor in the working environment, but the method is difficult to realize accurate compensation due to the spatial separation of the sampling point and the actual working point of the flexible electrode. Another key error source is systematic distortion of the resistance measurement itself. In order to meet the field deployment requirements, the flexible wearable sensor needs to be highly miniaturized and low in power consumption, so that the precision of a matched resistance detection circuit is far lower than that of a high-precision device such as a laboratory-level universal meter, and the flexible wearable sensor is easily influenced by common-mode interference such as contact resistance fluctuation, power supply noise, environment temperature and humidity fluctuation, analog-to-digital conversion quantization errors and the like. Although some schemes attempt to introduce reference elements, no effective suppression mechanism for common-mode interference in flexible dynamic fit scenarios has been developed. In addition, when the flexible electrode is integrated with multi-type functional fibers (such as strain sensitive fibers and temperature sensitive/reference fibers) to be cooperatively corrected, if the mechanical properties (especially the tensile coefficient or Young modulus) of each fiber material have significant differences, under the parallel stress state, the different fibers generate mutual constraint or relaxation effects, so as to interfere the resistance response of the main sensing fibers (such as silk nanofibers), namely, the resistance change does not simply correspond to the actual deformation of plant organs, but rather, the new errors caused by mechanical mismatch are superimposed. This problem is not identified in the prior art, nor is there a corresponding solution. Therefore, a data correction method capable of synchronously solving the problems of temperature compensation space mismatch, serious common-mode interference of resistance measurement and triple coupling of mechanical mismatch in multi-fiber integration is needed to improve the long-term monitoring precision and reliability of the plant flexible wearable sensor in a real agricultural environment. In view of this, the present invention has been made. Disclosure of Invention The first object of the invention is to provide a data correction method of a plant flexible wearable sensor, which can effectively realize high-precision, in-situ and anti-interference dynamic conversion of the diameter variation of plant stalks or fruit organs. A second object of the present invention is to provide a plant flexible wearable sensor. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: the invention provides a data correction method of a plant flexible wearable sensor, which comprises the following steps: (A) Providing a flexible electrode, wherein the flexible electro