A dynamic monitoring fruit diameter growth sensor and a linkage structure design method thereof

Abstract

The application discloses a kind of dynamic monitoring fruit diameter growth sensors and its linkage structure design method, including long horizontal bar, left clamp, right clamp, spring, displacement sensor, the left clamp includes long inclined bar, short inclined bar, horizontal moving bar;The short inclined bar one end is rotatably connected with long horizontal bar end, and the other end is rotatably connected with horizontal moving bar one end;The horizontal moving bar is rotatably connected with long inclined bar bottom end, and the other end of the horizontal moving bar is equipped with silica gel suction cup;The long inclined bar upper portion is rotatably connected with the long horizontal bar, and upper end is rotatably connected with left movable horizontal bar;The area surrounded by long inclined bar, short inclined bar, horizontal moving bar, long horizontal bar is parallelogram structure.The application is small and exquisite, adopts linkage structure, can adapt to different fruit diameter range fruit diameter measurement, more convenient and fast when using.

Description

Technical Field

[0001] This invention relates to the field of fruit diameter measurement, specifically to a dynamic monitoring sensor for fruit diameter growth and its linkage structure design method. Background Technology

[0002] The technical problem to be solved:

[0003] (1) The existing fruit diameter measuring device is usually structured as follows: a probe is set in the middle of a square frame, the fruit is placed in the square frame, and the probe moves to clamp the fruit, so that the fruit diameter can be measured. Although this design structure is simple, it is too large to be directly fixed to the tree. When used outdoors, the sensor is prone to shaking, and the fruit may detach from the sensor, resulting in relative displacement with the fruit. Moreover, this type of structure is bulky and cannot be clamped to the fruit for dynamic measurement, so it is impossible to obtain continuous experimental data in real time. Therefore, how to design a fruit diameter measuring structure that is smaller in size and does not produce relative displacement with the fruit has become a technical problem to be solved.

[0004] (2) For different types or varieties of fruit, different diameter sensors are needed, such as for apples and cherries. However, current measuring devices are difficult to apply to both large and small diameter fruits at the same time. Furthermore, due to the limitations of the measuring device's outer frame, there are many inconveniences when measuring small diameter fruits. Therefore, how to accurately design a diameter sensor that can adapt to different diameter ranges at the same time and make it more convenient to use is another technical problem to be solved. Summary of the Invention

[0005] To overcome the aforementioned shortcomings of the prior art, the technical problem to be solved by this invention is to provide a compact and widely adaptable fruit diameter sensor and its high-precision design method. To this end, the first aspect of this invention provides a sensor based on a parallelogram linkage mechanism, and the second aspect provides a linkage structure design method for this sensor, which converts displacement into fruit diameter values ​​by establishing a precise mathematical model. To achieve the above-mentioned objective, the technical solution adopted by this invention is as follows:

[0006] In a first aspect, the present invention provides a dynamic monitoring sensor for fruit diameter growth, characterized in that it includes a long horizontal bar, a left clamp and a right clamp symmetrically arranged at both ends of the long horizontal bar, and a displacement sensor;

[0007] The left clamp includes a long diagonal bar, a short diagonal bar, a horizontally movable bar, and a left movable horizontal bar;

[0008] One end of the short diagonal bar is rotatably connected to the end of the long horizontal bar, and the other end is rotatably connected to one end of the horizontal moving bar;

[0009] The middle part of the horizontal moving rod is rotatably connected to the bottom end of the long inclined rod, and the other end of the rod is provided with a silicone suction cup for contacting the fruit.

[0010] The upper middle part of the long diagonal bar is rotatably connected to the long horizontal bar, and its top end is rotatably connected to one end of the left movable horizontal bar.

[0011] The long diagonal bar, the short diagonal bar, the horizontal moving bar, and the corresponding parts of the long horizontal bar constitute a parallelogram linkage mechanism.

[0012] The right clamp is symmetrical to the left clamp in structure, and the top of its long diagonal bar is rotatably connected to one end of the right movable horizontal bar;

[0013] The measurement direction of the displacement sensor is parallel to the length direction of the long horizontal bar. The end of its displacement top rod is connected to the other end of the left movable horizontal bar through a displacement top plate, and its tail is connected to the other end of the right movable horizontal bar through a displacement tail plate.

[0014] Preferably, two springs are fixed in the middle of the long crossbar, and the other ends of the two springs are respectively connected to the middle of the long diagonal bars of the left and right clamps to provide a stable clamping force for the left and right clamps.

[0015] Preferably, the spring force is configured to both keep the silicone suction cup in close contact with the fruit surface without relative slippage, and ensure that the pressure applied to the fruit surface is below the fruit's damage threshold.

[0016] Preferably, the silicone suction cup is made of flexible silicone material, and its surface in contact with the fruit is designed as a concave arc surface, which increases friction and prevents slippage, while dispersing pressure through deformation to protect the fruit surface from mechanical damage.

[0017] Preferably, the displacement sensor is one of an LVDT displacement sensor, a grating displacement sensor, or a resistance ruler displacement sensor.

[0018] Secondly, the present invention provides a linkage structure design method for a dynamic monitoring fruit diameter growth sensor as described in the first aspect, characterized in that the method linearly amplifies and transmits the change in fruit diameter to the displacement sensor through the parallelogram linkage mechanism, and the method includes the following steps:

[0019] S1. Structural Parameter Definition: Define key structural parameters, including the distance b from the center point of the silicone suction cup on the horizontal moving rod that contacts the fruit to its connection point with the long inclined rod, the length L1 of the long inclined rod within the parallelogram structure, the length L2 of the long inclined rod outside the parallelogram structure, and the length a of the left movable horizontal rod.

[0020] S2, Calibration Data Acquisition: Select a known radius A standard sphere, simulating the fruit to be tested, is placed between the two silicone suction cups (24) of the sensor, and the corresponding displacement measured by the displacement sensor (4) is recorded. ,in ;

[0021] S3. Mathematical Model Establishment: Based on the kinematic relationship of the parallelogram linkage mechanism, the fruit radius is established. With displacement Conversion model between: in, Let be the order of the polynomial. and The model parameters are to be calibrated; S4, Parameter Fitting and Model Validation: Using the data collected in step S2... Group data ( , The parameters in the mathematical model are fitted using a regression algorithm. and The fitted model was then used to perform calculations on the validation set data to verify the reliability of the model.

[0022] Preferably, in step S4, the determination coefficient is calculated. To verify the reliability of the model, A coefficient of determination greater than 0.9 indicates that the model is reliable; The calculation formula is: in, For the sum of squared residuals, For the total sum of squares of deviations, This is the measured fruit diameter value. To fit the fruit diameter value to the model, This represents the average of the measured fruit diameter values.

[0023] Preferably, the method is applicable to the dynamic monitoring of fruit diameter in citrus, apples, or cherries; the polynomial order The value range is from 2 to 8.

[0024] Compared with existing technologies, the dynamic monitoring fruit diameter growth sensor and its linkage structure design method provided by this invention have the following significant advantages:

[0025] (1) This invention utilizes a parallelogram linkage mechanism and a flexible silicone suction cup in a coordinated design, combined with precisely configurable spring force, to enable the sensor to be gently and stably clamped onto the fruit. This effectively avoids damage to the fruit skin (such as pressure marks or punctures) that may be caused by traditional mechanical clamping methods, and also avoids measurement failures due to relative displacement or detachment from the fruit. It ensures continuous and uninterrupted monitoring throughout the entire fruit growth cycle, thereby obtaining complete and accurate growth curve data, filling the gap in existing technologies for real-time dynamic monitoring of fruit diameter, and realizing non-destructive, long-term, and dynamic monitoring of fruit growth.

[0026] (2) The present invention has a compact structure, strong adaptability and high measurement accuracy. The parallelogram mechanism not only ensures that the two measuring probes (silicone suction cups) move in translation during clamping, which can better fit the fruit surface of different shapes, but also linearly amplifies and transmits the minute changes in fruit diameter to the high-precision displacement sensor through the multi-stage lever principle, which significantly improves the sensitivity and measurement accuracy of the system. This linkage structure design enables the fruit diameter to be accurately calculated from the reading of a single sensor, eliminating the need for a complex multi-sensor layout and simplifying the system.

[0027] (3) This invention has a wide range of applicable fruit diameters and versatility. By changing the initial installation angle or length of the connecting rod, the sensor structure can adapt to a wide range of fruit diameters, from cherries to citrus fruits and apples, without changing the core design. Combined with the linkage structure design method provided by this invention, a high-precision measurement model (R) can be quickly established for any specific type or variety of fruit through the calibration process. 2 (>0.9), which makes the application of the present invention not limited to a single species and has extremely strong versatility. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the sensor of the present invention.

[0029] Figure 2 This is a schematic diagram illustrating the dynamic changes of the sensor of the present invention when holding fruits of different sizes.

[0030] Figure 3 This is a schematic diagram illustrating the measurement principle of the linkage structure design method of the present invention.

[0031] Among them, 1. Long horizontal bar; 2. Left clamp; 3. Right clamp; 4. Displacement sensor; 5. Left movable horizontal bar; 6. Spring; 21. Long diagonal bar; 22. Short diagonal bar; 23. Horizontal moving bar; 24. Silicone suction cup; 31. Right movable horizontal bar; 41. Displacement top bar; 42. Displacement top plate; 43. Displacement tail plate. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0034] Example 1:

[0035] like Figure 1 As shown, the dynamic monitoring fruit diameter growth sensor of the present invention mainly consists of a long horizontal bar 1, a left clamp 2, a right clamp 3, a displacement sensor 4, and a spring 6.

[0036] The left clamp 2 includes a long inclined rod 21, a short inclined rod 22, a horizontal moving rod 23, and a left movable horizontal rod 5. All connection points (circular nodes in the diagram) are rotatable connections. The upper end of the short inclined rod 22 is rotatably connected to the left end of the long horizontal rod 1, and the lower end is rotatably connected to the left end of the horizontal moving rod 23. The middle part of the horizontal moving rod 23 is rotatably connected to the bottom end of the long inclined rod 21, and a silicone suction cup 24 is installed on its right end. This silicone suction cup 24 is made of flexible material, and its contact surface is concave. Its core purposes are twofold: first, to use the high coefficient of friction of silicone to prevent relative sliding with the fruit surface during clamping, ensuring measurement stability; second, to disperse the clamping force through its own softness and deformation ability, avoiding crushing or puncturing the fruit skin, and protecting the fruit to the greatest extent.

[0037] The upper part of the long diagonal bar 21 is rotatably connected to the long horizontal bar 1, and its top end is rotatably connected to the left end of the left movable horizontal bar 5. The quadrilateral formed by the long diagonal bar 21, the short diagonal bar 22, the horizontal moving bar 23 and the long horizontal bar 1 is a parallelogram mechanism, which makes the movement of the two silicone suction cups 24 when holding the fruit translational, so as to better fit the fruit surface.

[0038] The right clamp 3 and the left clamp 2 are set in a mirror image symmetrically. Their configuration and connection relationship are the same as the left clamp 2. The top of the long diagonal bar is rotatably connected to the right movable horizontal bar 31.

[0039] The displacement sensor 4 (preferably an LVDT displacement sensor or a grating ruler) is fixed to the long horizontal bar 1 by a mounting bracket, with its measuring direction parallel to the long horizontal bar. A displacement top plate 42 is fixed to the end of its displacement top rod 41, and this plate is connected to the right end of the left movable horizontal bar 5. A displacement tail plate 43 is fixed to the tail of the displacement sensor 4, and this plate is connected to the left end of the right movable horizontal bar 31. When the fruit diameter changes, causing the left and right clamps to open and close, it drives the left and right movable horizontal bars to move, thereby changing the distance between the displacement top plate 42 and the displacement tail plate 43. This change is accurately measured by the displacement sensor 4.

[0040] Two springs 6 are installed in the middle of the long horizontal bar 1, with their other ends connected to the middle of the left and right long diagonal bars 21, respectively. The springs 6 provide a continuous and gentle clamping force. This force is carefully designed so that its lower limit is sufficient to overcome the weight of the sensor and the fruit, ensuring that the silicone suction cup 24 is stably attached and does not fall off; its upper limit is sufficient to ensure that the pressure applied to the fruit is far below the tolerance limit of the fruit peel tissue, thereby achieving non-destructive monitoring.

[0041] The entire sensor can be manufactured using lightweight materials such as aluminum alloy or engineering plastics to achieve weight reduction.

[0042] Example 2:

[0043] This embodiment uses citrus as an example to illustrate how to design and calibrate the above-mentioned sensor.

[0044] S1. Structural parameter definition: such as Figure 3 As shown, key structural parameters, such as distance b, length L1, L2, and a, are clearly defined. These parameters form the basis for establishing the kinematic model.

[0045] S2. Calibration Data Acquisition: Select eight standard spheres with known radii of 25, 30, 35, 40, 45, 50, 55, and 60 mm. Place them sequentially between the two silicone suction cups 24 of the sensor and record the displacement X measured by the displacement sensor 4. The corresponding results are 2.1, 3.0, 4.0, 5.3, 6.7, 8.2, 9.9, and 11.8 mm.

[0046] S3. Mathematical Model Establishment: Based on the motion relationship of the parallelogram linkage mechanism, a highly nonlinear relationship was found between the fruit radius R and the displacement X. Therefore, an eighth-order polynomial model was used for accurate fitting.

[0047]

[0048] S4. Parameter Fitting and Model Validation: The least squares method is used to fit the above 8 sets of data to obtain the model parameters.

[0049] Subsequently, five additional displacement values ​​(2.5, 4.5, 7.0, 9.0, 11.0 mm) were selected as the validation set, substituted into the fitted model to calculate the fitted fruit diameter, and compared with the actual fruit diameter (32.0, 44.5, 53.0, 60.0, 64.0 mm).

[0050] The coefficient of determination R was calculated. 2 ≈0.9996>0.9.

[0051] The results show that the calibration model established by this linkage structure design method has extremely high accuracy and can be fully used for accurate, dynamic, and non-destructive monitoring of citrus fruit diameter.

Claims

1. A sensor for dynamically monitoring fruit diameter growth, characterized in that, The device includes a long horizontal bar (1), a left clamp (2) and a right clamp (3) symmetrically arranged at both ends of the long horizontal bar (1), and a displacement sensor (4); the left clamp includes a long inclined bar (21), a short inclined bar (22), a horizontal moving rod (23), and a left movable horizontal rod (5); one end of the short inclined bar (22) is rotatably connected to the end of the long horizontal bar (1), and the other end is rotatably connected to one end of the horizontal moving rod (23); the middle part of the horizontal moving rod (23) is rotatably connected to the bottom end of the long inclined bar (21), and the other end is provided with a silicone suction cup (24) for contacting the fruit; the upper middle part of the long inclined bar (21) is rotatably connected to the long horizontal bar (1). The top of the rod is rotatably connected to one end of the left movable horizontal rod (5); the long inclined rod (21), the short inclined rod (22), the horizontal moving rod (23) and the corresponding parts of the long horizontal rod (1) constitute a parallelogram linkage mechanism; the right clamp is symmetrical to the left clamp, and the top of its long inclined rod is rotatably connected to one end of the right movable horizontal rod (31); the measuring direction of the displacement sensor (4) is parallel to the length direction of the long horizontal rod (1), the end of its displacement top rod (41) is connected to the other end of the left movable horizontal rod (5) through the displacement top plate (42), and its tail is connected to the other end of the right movable horizontal rod (31) through the displacement tail plate (43); The linkage structure design method of the dynamic monitoring fruit diameter growth sensor is as follows: the change in fruit diameter is linearly amplified and transmitted to the displacement sensor (4) through the parallelogram linkage mechanism. The method includes the following steps: S1, Structural parameter definition: Define key structural parameters, including the distance b from the center point of the silicone suction cup (24) on the horizontal moving rod (23) that contacts the fruit to its connection point with the long inclined rod (21), the length L1 of the long inclined rod (21) inside the parallelogram structure, the length L2 of the part outside the parallelogram structure, and the length a of the left movable horizontal rod (5); S2, Calibration data acquisition: Select a known radius A standard sphere, simulating the fruit to be tested, is placed between the two silicone suction cups (24) of the sensor, and the corresponding displacement measured by the displacement sensor (4) is recorded. ,in S3. Mathematical Model Establishment: Based on the kinematic relationship of the parallelogram linkage mechanism, the fruit radius is established. With displacement Conversion model between: in, Let be the order of the polynomial. and The model parameters are to be calibrated; S4, parameter fitting and model validation: using the data collected in step S2... Group data ( , The parameters in the mathematical model are fitted using a regression algorithm. and The fitted model was then used to perform calculations on the validation set data to verify the reliability of the model.

2. The sensor according to claim 1, characterized in that, Two springs (6) are fixed in the middle of the long horizontal bar (1). The other ends of the two springs (6) are respectively connected to the middle of the long diagonal bar (21) of the left and right clamps to provide stable clamping force for the left and right clamps.

3. The sensor according to claim 2, characterized in that, The spring (6) is configured to both keep the silicone suction cup (24) in close contact with the fruit surface without relative slippage and ensure that the pressure applied to the fruit surface is below the fruit damage threshold.

4. The sensor according to claim 1, characterized in that, The silicone suction cup (24) is made of flexible silicone material. Its surface in contact with the fruit is designed as a concave arc surface, which increases friction and prevents slippage while dispersing pressure through deformation to protect the fruit surface from mechanical damage.

5. The sensor according to claim 1, characterized in that, The displacement sensor (4) is one of an LVDT displacement sensor, a grating displacement sensor, or a resistance ruler displacement sensor.

6. The sensor according to claim 1, characterized in that, In step S4, the determination coefficient is calculated. To verify the reliability of the model, A coefficient of determination greater than 0.9 indicates that the model is reliable; The calculation formula is: in, For the sum of squared residuals, For the total sum of squares of deviations, This is the measured fruit diameter value. To fit the fruit diameter value to the model, This represents the average of the measured fruit diameter values.

7. The sensor according to claim 1, characterized in that, The method is applicable to dynamic monitoring of fruit diameter in citrus, apples, or cherries; the polynomial order... The value range is from 2 to 8.

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