A flexible strain sensing device for plant organ growth monitoring

Abstract

This invention employs the following technical solution: a flexible strain sensing device for monitoring plant organ growth, comprising a flexible substrate, a sensitive strain component, a spring clip, an air bladder, and a cavity; the flexible substrate consists of two sets of symmetrical flexible strip structures that can wrap and conform to the curved surface of a plant organ; the sensitive strain component is integrated into one set of flexible substrates on the side facing the plant organ, and the cavity is opened inside this set of flexible substrates, corresponding to the back side of the sensitive strain component; a flexible, bendable elastic metal is attached to the back side of the flexible substrate and the outer side of the cavity, which can limit the expansion of the cavity outwards from the flexible substrate and improve the monitoring accuracy of the sensitive strain component; the spring clip is connected to the outer side of the two sets of flexible substrates for clamping and fixing, and the air bladder is set on the surface of the spring clip that contacts the plant organ. This invention is applicable to monitoring the growth parameters of fruits or stems of fruits and vegetables such as eggplant, tomato, and pepper, achieving non-destructive, accurate, and continuous monitoring of growth deformation.

Description

Technical Field

[0001] This invention relates to the field of agricultural research, and more particularly to a flexible strain sensing device for monitoring plant organ growth. Background Technology

[0002] In the fields of agricultural production and plant research, the growth parameters of plant fruits and stems are key indicators that reflect core physiological information such as plant dry matter accumulation and water status. Accurate monitoring of these parameters is of great practical significance for plant health assessment and early warning of growth stress.

[0003] Current mainstream plant organ growth monitoring technologies mainly employ contact methods such as manual measurement with rulers and calipers, or non-contact methods such as image modeling and calculation after periodic photography. The former requires manual, plant-by-plant, and periodic on-site operation, which is time-consuming, labor-intensive, and the frequent physical contact can easily scratch the plant epidermis and crush young fruits / tender stems, affecting the normal growth of the plant. The latter is greatly affected by the shooting angle and lighting conditions, and cannot achieve real-time monitoring, only obtaining discrete growth data, which is easily affected by external environmental factors, such as rain, snow, and windy weather, making it difficult to guarantee the accuracy of the data. Secondly, the measurement operation is time-consuming and labor-intensive, and can easily cause physical damage to plant organs, affecting the normal growth of the plant. Thirdly, the resolution of the monitoring equipment is insufficient, unable to capture subtle changes in plant growth, and lacks temporal continuity, making it difficult to achieve full-process tracking of plant growth dynamics, which can no longer meet the needs of modern agriculture for precise and intelligent monitoring. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention discloses a flexible strain sensing device for monitoring plant organ growth. Using a flexible strain sensor as the basic monitoring unit, it resolves the tension issue of the clamps through an airflow sensing structure consisting of an airbag, a one-way valve, and a cavity. This enables non-destructive, accurate, continuous, and interference-resistant real-time monitoring of plant fruit / stem growth parameters, meeting the monitoring needs of the entire growth cycle of fruits and vegetables.

[0005] This invention employs the following technical solution: a flexible strain sensing device for monitoring plant organ growth, comprising a flexible substrate, a sensitive strain component, a spring clip, an air bladder, and a cavity; the flexible substrate consists of two sets of symmetrical flexible strip structures that can wrap and conform to the curved surface of the plant organ; the sensitive strain component is integrated into one set of flexible substrates on the side facing the plant organ, and the cavity is opened inside the set of flexible substrates and corresponds to the back side of the sensitive strain component; a flexible and bendable elastic metal is attached to the back side of the flexible substrate and the outer side of the cavity, which can limit the expansion of the cavity outward from the flexible substrate and improve the monitoring accuracy of the sensitive strain component; the spring clip is connected to the outer side of the two sets of flexible substrates for clamping and fixing, and the air bladder is set on the surface of the spring clip in contact with the plant organ, and is initially in a naturally expanded state, which can be squeezed as the plant organ grows and expands, and gas is delivered to the cavity through a connecting tube, thereby squeezing the sensitive strain component to achieve monitoring.

[0006] Furthermore, the sensitive strain component includes a flexible insulating composite substrate, interdigitated electrodes, nanoclusters, and an adhesive sealant layer stacked sequentially from the flexible substrate toward the plant organ; the flexible insulating composite substrate is bonded and fixed to the surface of the flexible substrate, the interdigitated electrodes are deposited on the outside of the flexible insulating composite substrate, the nanoclusters cover the conductive areas of the interdigitated electrodes, and the adhesive sealant layer covers the nanoclusters and the outside of the interdigitated electrodes.

[0007] Furthermore, the flexible insulating composite bottom layer is a polyimide-silica composite film, which has insulating properties and can isolate the interdigitated electrodes from the flexible substrate; the interdigitated electrodes are staggered comb-like structures made of metal conductive electrodes, with their electrode leads extending out of the adhesive seal layer for connecting external data acquisition circuits to achieve electrical signal transmission.

[0008] Furthermore, the nanoclusters are lattice structures formed by densely packed metal nanoparticles, which can change the lattice spacing with the deformation of the interdigitated electrodes and cause changes in the overall electrical signal; the adhesive sealant is a transparent flexible adhesive, which is set away from the pin area of ​​the interdigitated electrodes to achieve encapsulation and protection of the sensitive strain components without affecting the conductivity of the electrodes.

[0009] Furthermore, the connecting pipe is a one-way valve type pipe, and the one-way valve conduction direction is from the airbag to the cavity, allowing only the gas in the airbag to flow into the cavity in one direction, preventing the gas in the cavity from flowing back.

[0010] Furthermore, the flexible substrate is made of flexible materials such as latex, TPU, or PDMS.

[0011] Furthermore, the airbag is a multi-chamber graded inflatable airbag, including an inner chamber and an outer chamber, which are interconnected by a micro-flow-limiting orifice, and the connecting tube is connected to the outer chamber; the elastic coefficient of the inner chamber is lower than that of the outer chamber; the opening size of the micro-flow-limiting orifice is larger on the side closer to the inner chamber than on the side closer to the outer chamber.

[0012] Furthermore, the air bladder has an arc-shaped groove and a rectangular groove on the inner wall facing the plant organ. The arc-shaped groove is used to create a slight negative pressure to adhere to the plant surface when the plant organ is slightly shaken, and the rectangular groove is reserved for the plant epidermis to breathe.

[0013] The specific beneficial effects of this invention are as follows: (1) The present invention adopts a flexible substrate, a sensitive strain component and a spring clip to form a clamping and fitting monitoring structure. The design is unique and has excellent fit. It can tightly wrap and fit the curved surface of plant organs, realize the seamless fit between the device and the plant surface, eliminate the need for manual on-site operation of each plant periodically, and the flexible fitting method avoids scratching and squeezing the plant epidermis, young fruit / tender stem. While ensuring efficient and effective monitoring of growth deformation, it also achieves non-destructive monitoring of plants.

[0014] (2) The present invention forms a synergistic force transmission structure by combining the air bladder on the surface of the spring clip with the cavity and the elastic metal on the outside of the flexible substrate. It can accurately convert the pressure on both sides generated by the growth and expansion of the plant into gas pressure, and efficiently and without loss transmit it to the sensitive strain component, ensuring that the subtle growth deformation of the plant can be accurately detected and captured, and greatly improving the monitoring resolution and accuracy.

[0015] (3) The present invention adopts a multi-chamber graded structure with low inner elasticity and high outer elasticity for the air bladder, and is equipped with micro flow-limiting holes of different diameters. It can be graded to adapt to the turgor pressure of plants at different growth stages, which can avoid pressure damage during the young fruit stage and ensure stable gas pressure output and rapid conduction during the mature plant stage. It avoids the problem of adapting a single air bladder to the entire growth cycle. In addition, the arc-shaped groove on the inner wall of the air bladder can form a slight negative pressure to prevent slippage and ensure stable force transmission. The rectangular groove reserves breathing space to prevent the plant epidermis from being damp and damaged, thus improving the overall practical effect. Attached Figure Description

[0016] Figure 1 This is a structural illustration of the present invention; Figure 2 This is a top-view cross-sectional view of the flexible substrate structure of the present invention; Figure 3 This is an enlarged view of the structure of the sensitive strain component of the present invention; Figure 4 This is a cross-sectional view of the airbag structure of the present invention; Figure 5 This is an enlarged view of the structure at point A of the present invention; Figure 6 This is a view of the inner side of the airbag structure of the present invention.

[0017] 1-Flexible substrate, 11-Elastic metal, 2-Sensitive strain component, 21-Flexible insulating composite underlayer, 22-Interdigital electrode, 23-Nano cluster, 24-Adhesive sealant, 3-Spring clip, 4-Airbag, 41-Inner chamber, 42-Outer chamber, 43-Micro flow-limiting orifice, 44-Arc groove, 45-Rectangular groove, 5-Cavity, 6-Connecting tube. Detailed Implementation

[0018] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] Reference manual attached Figure 1-6 This invention provides a flexible strain sensing device for monitoring plant organ growth, which is mainly suitable for monitoring the growth parameters of fruits or stems of vegetables such as eggplant, tomato, and pepper, and realizes non-destructive, accurate and continuous monitoring of growth deformation.

[0023] A flexible strain sensing device for monitoring plant organ growth includes a flexible substrate 1, a sensitive strain component 2, a spring clip 3, an air bladder 4, a cavity 5, and a connecting tube 6. The flexible substrate 1 can be attached to the surface of the curved shape of common plant organs (such as eggplant fruit and stem). The flexible substrate 1 is preferably made of flexible materials such as latex, TPU, or PDMS, which have good bending and fitting properties.

[0024] A set of flexible substrates 1 has a sensitive strain component 2 integrated on the side facing the plant organ. The sensitive strain component 2 is the core sensing unit of the device, including a flexible insulating composite bottom layer 21, interdigitated electrodes 22, nanoclusters 23 and adhesive sealing layer 24. The layers are stacked sequentially from the flexible substrate 1 toward the plant organ.

[0025] Specifically, the flexible insulating composite substrate 21 is a polyimide-silica composite film, which is tightly bonded to the surface of the flexible substrate 1 on one side. It possesses excellent insulation properties, effectively isolating the interdigitated electrodes 22 from the flexible substrate 1, avoiding leakage, signal crosstalk, and other problems, thus ensuring sensing accuracy. The interdigitated electrodes 22 are deposited on the outside of the flexible insulating composite substrate 21. They are interlaced comb-like structures made of metal conductive electrodes. The electrode leads of the interdigitated electrodes 22 extend beyond the subsequent adhesive sealing layer 24, used for connecting to external microcontrollers, data terminals, and other data acquisition circuits to achieve electrical signal transmission. The nanoclusters 23 are lattice structures formed by densely packed metal nanoparticles, completely covering the conductive area of ​​the interdigitated electrodes 22, forming an integrated sensing structure. When the interdigitated electrodes 22 deform with plant growth, the lattice spacing of the nanoclusters 23 changes synchronously, thereby causing a change in the overall electrical signal and achieving precise monitoring of subtle deformations. In addition, the adhesive sealant 24 is a transparent flexible adhesive that covers the outside of the nanoclusters 23 and the interdigitated electrodes 22, thereby encapsulating and protecting the sensitive strain component 2.

[0026] This invention also optimizes the structure of the airbag 4 to adapt it to the monitoring needs of plant organs throughout their entire growth cycle, from young fruit / tender stem to mature plant. Specifically, the airbag 4 is integrally molded into a dual-chamber, graded expansion structure comprising an inner chamber 41 and an outer chamber 42. The inner chamber 41 is made of food-grade soft silicone with a Shore hardness of 20A, which has a low elastic modulus and is specifically adapted to the slight compressive force of 5-10N for young fruit / tender stem of fruits and vegetables such as eggplant, tomato, and pepper. The outer chamber 42 is made of food-grade silicone with a Shore hardness of 40A, which has a high elastic modulus and is adapted to the large expansion force of 20-50N for mature plant organs. A micro-flow-limiting hole 43 is opened at the connection between the inner chamber 41 and the outer chamber 42. The flow-limiting hole 43 has a different diameter structure. The opening diameter on the side closer to the inner chamber 41 is set to 0.1mm-0.15mm, and the opening diameter on the side closer to the outer chamber 42 is set to 0.05mm-0.08mm. This allows the gas to be quickly forced into the outer chamber 42 when the inner chamber 41 is compressed. At the same time, the air inlet end of the connecting pipe 6 is connected to the outer chamber 42 to ensure that the gas can be delivered to the cavity 5 in a timely manner through the connecting pipe 6 after being conducted through the flow-limiting hole 43.

[0027] Meanwhile, on the inner wall of the airbag 4 facing the plant organ, an arc-shaped groove 44 and a rectangular groove 45 are integrally formed using an in-mold molding process. The arc-shaped groove 44 is evenly distributed in a continuous spiral shape on the inner wall of the airbag. When the plant organ shakes slightly due to factors such as wind, a slight negative pressure is formed between the arc-shaped groove 44 and the plant surface, which realizes the adsorption and adhesion between the airbag and the plant surface and prevents slippage. The rectangular groove 45 is distributed in an array in the gaps between the arc-shaped grooves 44, leaving a small air gap for the plant epidermis to ensure normal respiration of the plant epidermis and avoid the problems of stuffiness and rot caused by long-term adhesion.

[0028] After two sets of flexible substrates 1 are wrapped around the plant organ, they are clamped on the outside by spring clips 3. The spring clips 3 are elastic stainless steel clips. When clamping, the spring clips 3 are close to the sides of the plant organ, and after clamping, the two sets of flexible substrates 1 are tightly attached to the surface of the plant organ. At the same time, an air bladder 4 is provided on the surface of the spring clip 3 that contacts the plant organ. While clamping and fixing the two sets of flexible substrates 1, the air bladder 4 abuts against the surface of the plant organ. The interior of the set of flexible substrates 1 with sensitive strain components 2 has a cavity 5 corresponding to the back side of the sensitive strain components 2. The cavity 5 is connected to the air bladder 4 through a connecting tube 6. At the same time, it is necessary to ensure that the inner chamber 41 of the air bladder 4 faces the plant organ side. After assembly, the air bladder 4 is initially in a naturally inflated state. When the plant is in the young fruit / tender stem stage, the slight compression caused by the expansion of the organ The force acts only on the inner chamber 41. After the inner chamber 41 is compressed, the gas inside is quickly forced into the outer chamber 42 through the micro-flow limiting hole 43, and then transported to the cavity 5 in one direction through the connecting pipe 6. When the plant enters the mature stage, the organ swelling pressure increases and acts on both the inner chamber 41 and the outer chamber 42 at the same time. The dual chambers are simultaneously compressed to achieve staged exhaust, ensuring that the gas pressure is stably transported to the cavity 5, which in turn squeezes the sensitive strain component 2 to deform synchronously, thereby causing changes in the electrical signal of the cluster lattice electrode. The amount of growth change is then obtained through data acquisition and conversion.

[0029] Among them, the connecting pipe 6 is a one-way valve type pipe. The one-way valve is directed from the airbag 4 to the cavity 5, allowing only the gas in the airbag 4 to flow into the cavity 5 in one direction. This can effectively prevent the gas in the cavity 5 from flowing back and ensure the accuracy of deformation monitoring.

[0030] Among them, an elastic metal 11 is attached to the back of the flexible substrate 1 at the outer position of the cavity 5. The elastic metal 11 is a flexible and bendable metal. Its function is that when the gas inside the airbag 4 is squeezed into the cavity 5, the cavity 5 will expand to both sides. Due to the setting of the elastic metal 11, the air pressure inside the cavity 5 will preferentially squeeze the sensitive strain component 2 on the inner side, thereby improving the accuracy of monitoring.

[0031] Furthermore, it should be added that, in actual use, a shallow groove is opened on the back side of the flexible substrate 1 corresponding to the area of ​​the cavity 5, and the elastic metal 11 is embedded in the shallow groove and fixed by the flexible adhesive layer to prevent the elastic metal 11 from warping or shifting due to long-term use and repeated bending, so as to ensure that its limiting effect on the expansion of the outside of the cavity 5 remains stable and to prevent force transmission deviation caused by metal displacement.

[0032] The workflow of this invention is as follows: S1: Wrap the plant organ (if it is fruit) with two sets of flexible substrates 1, clamp it with spring clips 3, and the airbag 4 abuts against the plant surface; S2: Plant growth compresses the airbag 4 → Gas inside the airbag flows into the cavity 5 through the one-way valve connecting pipe 6 → The cavity expands. S3: Cavity expansion and compression sensitive strain component 2 (elastic metal 11 enhances this effect) → interdigitated electrode 22 deforms with component → lattice spacing of nanoclusters 23 changes → electrical signal changes; S4: The pins of the interdigital electrode 22 transmit electrical signals to the acquisition circuit → which are then converted into growth change data for real-time monitoring.

[0033] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

Claims

1. A flexible strain sensing device for plant organ growth monitoring, characterized by, Includes flexible substrate (1), sensitive strain component (2), spring clip (3), airbag (4), cavity (5); The flexible substrate (1) consists of two sets of symmetrical flexible strip structures that can wrap and fit onto the curved surface of plant organs; The sensitive strain component (2) is integrated into one of the flexible substrates (1) on the side facing the plant organ, and the cavity (5) is opened inside the flexible substrate (1) and corresponds to the back side of the sensitive strain component (2). The flexible substrate (1) has a flexible and bendable elastic metal (11) attached to the outside of the cavity (5) on the back side, which can limit the expansion of the cavity (5) to the outside of the flexible substrate (1) and improve the monitoring accuracy of the sensitive strain component (2). The spring clip (3) is connected to the outside of two sets of flexible substrates (1) to achieve clamping and fixing. The air bag (4) is set on the surface of the spring clip (3) that is in contact with the plant organ. It is initially in a naturally expanded state and can be squeezed as the plant organ grows and expands. It also delivers gas to the cavity (5) through the connecting pipe (6) to squeeze the sensitive strain component (2) for monitoring.

2. A flexible strain sensing device for monitoring growth of plant organs according to claim 1, wherein, The sensitive strain component (2) includes a flexible insulating composite substrate (21), interdigitated electrodes (22), nanoclusters (23) and adhesive sealant (24) stacked sequentially from the flexible substrate (1) toward the plant organ. The flexible insulating composite substrate (21) is bonded and fixed to the surface of the flexible substrate (1), the interdigitated electrode (22) is deposited on the outside of the flexible insulating composite substrate (21), the nanoclusters (23) cover the conductive area of ​​the interdigitated electrode (22), and the adhesive seal layer (24) covers the outside of the nanoclusters (23) and the interdigitated electrode (22).

3. A flexible strain sensing device for monitoring plant organ growth according to claim 2, characterized in that, The flexible insulating composite bottom layer (21) is a polyimide-silica composite film, which has insulating properties and can isolate the interdigitated electrode (22) from the flexible substrate (1). The interdigitated electrode (22) is an interlaced comb structure made of metal conductive electrodes, with its electrode pins extending out of the glue seal layer (24) for connecting to an external data acquisition circuit to realize electrical signal transmission.

4. A flexible strain sensing device for monitoring plant organ growth according to claim 3, characterized in that, The nanoclusters (23) are lattice structures formed by densely packed metal nanoparticles, and the lattice spacing can change with the deformation of the interdigitated electrodes (22) and cause changes in the overall electrical signal. The adhesive sealant (24) is a transparent flexible adhesive that is set away from the pin area of ​​the interdigitated electrode (22) to achieve encapsulation and protection of the sensitive strain component (2) without affecting the conductivity of the electrode.

5. A flexible strain sensing device for monitoring plant organ growth according to claim 4, characterized in that, The connecting pipe (6) is a one-way valve type pipe, and the one-way valve conduction direction is from the airbag (4) to the cavity (5), allowing only the gas in the airbag (4) to flow into the cavity (5) in one direction, preventing the gas in the cavity (5) from flowing back.

6. A flexible strain sensing device for monitoring plant organ growth according to claim 5, characterized in that, The flexible substrate (1) is made of latex, TPU or PDMS flexible material.

7. A flexible strain sensing device for monitoring plant organ growth according to claim 6, characterized in that, A shallow groove is opened on the back side of the flexible substrate (1) corresponding to the cavity (5). The elastic metal (11) is embedded in the shallow groove and fixed by the flexible adhesive layer to prevent the elastic metal (11) from warping or shifting due to long-term use and repeated bending.

8. A flexible strain sensing device for monitoring plant organ growth according to claim 7, characterized in that, The airbag (4) is a multi-chamber graded inflatable airbag, including an inner chamber (41) and an outer chamber (42). The inner chamber (41) and the outer chamber (42) are interconnected through a micro-flow limiting hole (43). The connecting tube (6) is connected to the outer chamber (42). The elastic modulus of the inner chamber (41) is lower than that of the outer chamber (42); The opening size of the micro-flow limiting orifice (43) on the side closer to the inner chamber (41) is larger than the opening size on the side closer to the outer chamber (42).

9. A flexible strain sensing device for monitoring plant organ growth according to claim 8, characterized in that, The air bladder (4) has an arc-shaped groove (44) and a rectangular groove (45) on the inner wall of the plant organ. The arc-shaped groove (44) is used to form a slight negative pressure to adhere to the plant surface when the plant organ shakes slightly. The rectangular groove (45) is reserved for the plant epidermis to breathe.

Images