CN113607647B - Crop growth information sensor self-balancing device and design method thereof - Google Patents

Abstract

The invention discloses a self-balancing device for a crop growth information sensor. The balancing device is a balancing ring installed on the sensor housing. The balancing ring includes at least two layers of movably connected cocircular center connecting rings. The diameter of the inner ring of the innermost layer is Both ends are movably connected to the sensor housing. The connection point of the two adjacent connecting rings is located on the diameter of the outer connecting ring. There is a handle on the outer wall of the outermost outer ring; there is at least one connection point between the two adjacent connecting rings. The connection lines between the connection points of the inner ring and the sensor housing are perpendicular to each other in the horizontal plane. Design each layer of the connection ring so that it meets the requirement that the maximum angle of rotation θ is greater than or equal to the maximum pitch angle of the connection ring in use. The invention is installed on the sensor housing, and by holding the handle, the sensor can adjust itself to maintain a balanced state. Depending on the height of the crop to be measured, the required maximum rotation angle of the balance ring is different, which provides a basis for the size design of the balance ring.

Description

A crop growth information sensor self-balancing device and design method thereof

Technical Field

The invention relates to the field of crop growth information, and more specifically, to a crop growth information sensor self-balancing device and a design method thereof.

Background Art

The upper and lower surfaces of the crop growth information sensor simultaneously receive sunlight and crop reflected light, obtain crop reflectivity, and then invert to obtain crop growth information. When monitoring crop reflectivity, the reflected light and sunlight receiving surfaces are required to be in a horizontal state. Existing sensors are manually adjusted by observing a level ruler during use, which is time-consuming and inefficient. In addition, crop growth sensors are mostly integrated on portable devices and need to be held by people for measurement. During the measurement process, it is difficult to manually ensure that the reflected light and sunlight receiving surfaces are always in a horizontal state, which causes measurement errors.

In practical applications, various crops have different heights, and manual handheld measurement will form different pitch and tilt angles. According to the different heights of the crops to be measured, a balancing device with a suitable size to match the sensor needs to be designed to meet the measurement requirements.

Summary of the invention

In view of the shortcomings of the prior art, the purpose of the present invention is to provide a crop growth information sensor self-balancing device and a design method thereof to solve the above-mentioned problems. According to different heights of crops to be measured, suitable sizes are designed to meet the measurement requirements of a certain crop, thereby improving the design efficiency and success rate.

To achieve the above object, the present invention provides the following technical solutions:

A crop growth information sensor self-balancing device, the balancing device is a balancing ring mounted on a sensor housing, the balancing ring comprises at least two layers of movably connected co-centric connecting rings, the inner ring of the innermost layer is movably connected to the sensor housing at both ends of the diameter, the connecting points of two adjacent connecting rings are located on the diameter of the outer connecting ring, and a handle is provided on the outer wall of the outer ring of the outermost layer; there is at least one connecting line of the connecting points of two adjacent connecting rings, which is perpendicular to the connecting line of the inner ring and the sensor housing in a horizontal plane;

The inner diameter and height of each layer of connecting rings affect the rotation angle of the connecting rings to adjust the sensor's central axis vertically downward. When the handle rotates left or right or pitches beyond this maximum angle, the outer wall of the sensor will touch the connecting ring and lose the function of automatically adjusting the balance. Therefore, the inner diameter and height of the balance ring should be designed according to the height of the target crop to be detected and the maximum angle that needs to be adjusted in actual applications.

Design the connecting rings at each layer so that the maximum rotation angle θ is greater than or equal to the maximum pitch angle of the connecting ring during use.

,

Where r is the radius of the sensor housing, R is the inner radius of each layer of connecting ring, and h is the distance from each layer of connecting ring to its adjacent inner layer connecting ring or the connection point of the sensor housing to the bottom edge of the connecting ring.

A further improved technical solution of the present invention is that the inner ring and the sensor housing are movably connected by providing a radial clamping column on the inner wall of the inner ring, which is movably clamped with a mounting hole provided on the sensor housing.

A further improved technical solution of the present invention is that the clamping column is cylindrical and the top is hemispherical. The clamping column is set to be cylindrical and the top is set to be semicircular. When the sensor sinks under its own gravity, the contact surface between the clamping column and the mounting hole can be ensured to be small, so that the balance ring is mounted on the sensor housing and is sensitive. The top of the clamping column and the mounting hole are mutually in conflict, that is, they are pressed against the inner wall of the mounting hole, and the sensor is effectively prevented from swinging for a long time and not entering a stable state due to being too sensitive.

A further improved technical solution of the present invention is that a friction surface is provided on the outer surface of the clamping column and/or the inner surface of the mounting hole. The friction surface is provided on the inner surface of the clamping column or the outer surface of the mounting hole or both, thereby increasing the contact friction between the two and further reducing the sensor from swinging for a long time without entering a stable state due to being too sensitive.

A further improved technical solution of the present invention is that the movable connection of two adjacent connecting rings is that a pin is arranged on the inner wall of the outer connecting ring, a connecting hole is opened on the side wall of the inner connecting ring, and the pin is movably connected in the connecting hole. The pin connection has good adjustment sensitivity.

A further improved technical solution of the present invention is that the connection point between each layer of connecting ring and its adjacent inner layer connecting ring or sensor housing is located at the center of the height of the connecting ring, which is convenient for design and calculation, and the mechanical strength of the connecting ring is good.

A further improved technical solution of the present invention is that the height of the connecting ring is 2-50 mm, so that the mechanical strength of the connecting ring is ensured and the structure is more compact and reasonable.

A further improved technical solution of the present invention is that the movable connection point between the inner ring and the sensor housing is located within the upper third of the sensor, which is conducive to the sensor quickly entering a balanced state.

A further improved technical solution of the present invention is that when the axis of the sensor is vertical and the inner and outer balance rings are horizontal, the axis of the handle is on an extension line of a connecting line between the inner ring and the sensor housing connection point.

The present invention also provides a design method for a crop growth information sensor self-balancing device.

(1) Determine the sensor model according to the crop to be tested and obtain the sensor housing radius r ; determine the connection ring height H according to the requirements of mechanical strength and ease of installation; the distance from each layer of connection ring to its adjacent inner layer connection ring or the sensor housing connection point to the bottom edge of the connection ring is h ;

(2) Design the inner diameter R of the left-right tilting connecting ring: First, preset the maximum pitch angle γ of the connecting ring generated by the left-right rotation of the handle during use, and then , the design R value satisfies θ≥γ ;

(3) Design the inner diameter R of the front and rear tilting connecting ring: the crop height or canopy height during measurement is _{preset to be hcrop, the distance of the sensor above the crop is hmeasure ,} the horizontal distance between the surveyor and the crop is L , the balance ring handle is connected to the long pole, and the height of the position where the _surveyor holds the long pole from the ground is hhand . When the crop is short and the long pole is tilted downward for measurement, the inclination angle of the long pole to the horizontal plane is γ . When the crop is high and the pole is tilted upward for measurement, the inclination angle between the pole and the horizontal plane is γ . ; Based on this, the maximum pitch angle γ of the connecting ring in use when monitoring the minimum and maximum plant heights of crops is calculated. , the design R value satisfies θ≥γ ;

(4) Compare the R calculated in step (2) with that in step (3). If the R of the inner connecting ring is significantly smaller than the R of the outer connecting ring, the design dimensions of the connecting rings of each layer meet the requirements, or the R of the inner connecting ring can be appropriately increased for ease of installation. If the R of the inner connecting ring is greater than or equal to or slightly smaller than the R of the outer connecting ring, resulting in the inability to install, the R of the outer connecting ring can be appropriately increased.

Beneficial effects of the present invention:

1. The present invention is mounted on the sensor housing. By holding the handle, the sensor can adjust itself to maintain a vertical balance state with extremely high efficiency, so that the upper and lower end surfaces for collecting sunlight and crop reflected light are in a horizontal state, which improves the accuracy of the sensor monitoring data and is conducive to promoting the popularization and application of agricultural information sensors.

2. Due to the different heights of the crops to be measured, the required maximum rotation angles of the balance ring are different. The present invention provides theoretical guidance for the size design of the sensor balance device, improves the design efficiency and success rate, and is conducive to promoting the design and application of the balance device.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram of the structure of the present invention;

FIG2 is a schematic diagram showing the design and calculation of the maximum rotation angle θ of the inner ring;

FIG3 is a schematic diagram showing the relationship between the maximum angle of rotation of the inner ring and changes in its radius and height;

FIG4 is a schematic diagram showing the design and calculation of the maximum rotation angle θ of the outer ring;

FIG5 is a diagram showing the maximum pitch angle γ of the outer ring predicted when the plant to be tested is the shortest in Example 1;

FIG6 is a diagram showing the predicted maximum pitch angle γ of the outer ring when the plant to be tested is at its highest in Example 1;

FIG. 7 is a diagram showing the maximum pitch angle γ of the outer ring predicted when the plant to be tested is the shortest in Example 2;

FIG8 is a diagram showing the predicted maximum pitch angle γ of the outer ring when the plant to be tested is at its highest in Example 2;

FIG9 is a diagram showing the predicted maximum pitch angle γ of the outer ring when the plant to be tested is the shortest in Example 3;

FIG. 10 is a diagram showing the predicted maximum pitch angle γ of the outer ring when the plant to be tested is at its highest in Example 3.

DETAILED DESCRIPTION

As shown in FIG1 , the balancing device of the present invention is a balancing ring mounted on a sensor housing 1, and the balancing ring is formed by an inner ring and an outer ring movably connected. Radial cylindrical clamping columns 5 are provided on the inner walls at both ends of the diameter of the inner ring 2, and are movably engaged with the mounting holes opened on the sensor housing 1. The top of the clamping column 5 is hemispherical, and a friction surface is provided on the outer surface of the clamping column and/or the inner surface of the mounting hole (not shown in the figure). The outer ring 3 is cocentric with the inner ring 2, and the outer ring 3 and the inner ring 2 are movably connected on the diameter of the outer ring 3 by a pin 6, that is, a pin 6 is arranged on the inner wall of the outer ring, and a connecting hole is opened on the side wall of the inner ring, and the pin is movably inserted into the connecting hole to form a movable connection, and the connecting line of the inner ring and the sensor housing connection point and the connecting line of the outer ring and the inner ring connection point are perpendicular to each other in the horizontal plane, the connecting point of the outer ring and the inner ring is located at the center of the height of the outer ring and the inner ring, and the connecting point of the inner ring and the sensor housing is located at the center of the height of the inner ring, and is located within the upper third of the sensor housing. A handle 4 is provided on the outer wall of the outer ring 3. When the axis of the sensor is vertical and the inner and outer balance rings are horizontal, the axis of the handle 4 is on the extension line of the connecting line between the inner ring and the sensor housing.

The inner diameter and height of the connecting ring affect the rotation angle of the connecting ring to adjust the central axis of the sensor vertically downward. When the handle rotates left or right beyond a certain angle, the outer wall of the sensor housing will touch the inner ring. When the handle pitches beyond a certain angle, the outer wall of the sensor housing will touch the outer ring, and the automatic balance adjustment function will be lost. The handle rotation should be kept within a small angle range as much as possible. The pitch movement of the handle is related to the height of the crop. For different heights of crops to be observed, the inner diameter and height of the balance ring are designed according to the maximum angle that can be adjusted in actual applications.

The maximum angle θ ₁ of the inner ring rotation is designed. As shown in FIG2 , the radius of the cylindrical sensor housing is r , the inner diameter of the inner ring is R ₁ , the height of the inner ring is 2 h ₁ , and the central axis of the clamp connecting the inner ring and the sensor housing is located at the center of the inner ring height. Therefore, the distance from the central axis of the clamp to the bottom edge of the inner ring is h ₁ . When the sensor is vertically downward and the inner and outer rings are horizontal, the intersection of the central axis of the clamp 5 and the central axis of the sensor is point O ₁ , the horizontal intersection of the radius of the inner wall of the inner ring passing through point O ₁ and the inner wall of the inner ring is A , the distance from point O ₁ to point A is R ₁ , O ₁ A is perpendicular to the central axis of the sensor, the vertical projection point of point A on the lower edge of the inner wall of the inner ring is B, the distance from point O ₁ to point B is l ₁ , the angle between O ₁ A and O ₁ B is a ₁ , when the inner ring rotates to the maximum angle θ ₁ , the lower edge of the inner ring touches the outer wall of the sensor housing facing vertically downward. At this time, A rotates to A′ , B rotates to B′ , O The angle between the line O ₁ B′ connecting point ₁ and the lower edge of the inner ring and the center axis of the sensor is β ₁ , and the angle between O ₁ A and O ₁ A′ is ,

;

The variation of θ ₁ with R ₁ and h ₁ is shown in Figure 3. The inner ring must meet the requirements of both mechanical strength and aesthetics, so the preferred range of h ₁ is 1mm~25mm. Assuming that the sensor r =40mm, the range of R ₁ is from 50mm to 150mm. As shown in Figure 3, the adjustable θ ₁ range of h ₁ is much smaller than the adjustable θ ₁ range of R _1. Therefore, in the actual design, it is preferred to adjust the maximum inclination angle of the inner flat ring by adjusting R _1. Under the premise of meeting the mechanical strength, h ₁ can be appropriately reduced.

Design the maximum angle θ ₂ of the outer ring rotation, as shown in Figure 4, the radius of the cylindrical sensor shell is r , the inner diameter of the outer ring is R ₂ , the height of the outer ring is 2 h ₂ , the connection point between the outer ring and the inner ring is located at the center of the height of the outer ring and the inner ring, so the distance from the connection point between the outer ring and the inner ring to the bottom edge of the outer ring is h _{2 ,} when the sensor is vertically downward and the inner and outer rings are horizontal, the intersection of the center axis of the pin shaft 6 at the connection point of the inner and outer rings and the center axis of the sensor is point O ₂ , the horizontal intersection of the radius of the inner wall of the outer ring passing through point O 2 and the inner wall of the outer ring is C , the distance from point O ₂ to point C is R ₂ , O ₂ C is perpendicular to the center axis of the sensor, the vertical projection point of point C on the lower edge of the inner wall of the outer ring is D, the distance from point O ₂ to point D is l ₂ , the angle between O ₂ C and O ₂ D is a ₂ , when the outer ring rotates to the maximum angle θ ₂ , the lower edge of the outer ring touches the outer wall of the sensor shell facing vertically downward, and at this time C rotates to C′ , D rotates to D' , the angle between the _line O2D _' connecting point O2 and the lower edge of the outer _ring and _the central axis of the sensor is β2 _, and the angle between O2C and O2C ' is , the same as the inner ring design,

;

When designing the gimbal, θ2 must be greater than the maximum inclination angle of the gimbal in practical applications. If the _{angle θ2} is not large enough, _the inner diameter R2 of the outer ring can be increased or the height h2 from the connection point between the outer ring and the inner _ring to the bottom edge of the outer ring can be reduced. However, since reducing h2 will reduce the mechanical strength of the _gimbal , and the angle range of θ2 _that can be increased is _small , it is preferred to increase the inner diameter R2 of the outer ring.

In actual applications _, when the line connecting the two connection points of the inner and outer rings is perpendicular to the central axis of the handle, θ2 must be greater than or equal to the maximum inclination angle of the long rod connected to the handle in the application; when the line connecting the two connection points of the inner and outer rings is parallel to the central axis of the handle, θ1 must be greater than or equal to the maximum inclination angle of the long rod connected to the handle in the application _.

The present invention has compiled a table of sensors with different combinations of r, R and h under common sizes, see Table 1, which can be used as a reference when designing a balancing device.

Table 1 θ under different r , R , h

Example 1

The crop sensor is used to monitor wheat, r = 20mm, the balance ring is made of metal (such as stainless steel or aluminum alloy), and two layers of connecting rings are used. According to the requirements of aesthetics and mechanical strength, h ₁ = h ₂ = 2mm, the line connecting the two connection points of the inner and outer rings is perpendicular to the central axis of the handle, and the sensor is used to measure the period from the crop growing to the plant height of 1cm to the harvest. The handle of the outer ring of the balance device is fixed on the long pole, and the measurement personnel hold the long pole for measurement. The height of the hand holding the long pole from the ground is set to 90cm. The horizontal distance between the person and the crop during measurement is 100cm, and the rotation of the long pole does not exceed 30°. When measuring from the plant height of 1cm to before the row is closed, the sensor is 20cm above the canopy, and when measuring after the row is closed, the sensor is 50cm above the canopy. In order to improve the adaptability of the balance ring in actual work, it is assumed that the maximum height of wheat is 150cm.

The first step is to design the inner diameter R ₁ of the inner ring. Since the rotation of the long rod does not exceed 30°, the design of R ₁ only needs to satisfy θ ₁ ≥ 30°. It can be seen from the calculation method of the present invention or from Table 1 that when R ₁ = 25 mm, θ ₁ = 33°＞30°, which meets the requirements.

The second step is to determine the minimum size of the inner diameter of the outer ring to meet the measurement requirements when the plant height is 1 cm. When measuring wheat with a height of 1 cm, combined with Figure 5, the calculation method of the angle γ between the long pole and the horizontal plane is as follows: AB is the plant height, equal to 1 cm, point C is the sensor position, BC is 20 cm long, point F is the standing position of the measurement personnel, AF is the horizontal distance between the measurement personnel and the crop, 100 cm, DF is the height of the position holding the long pole from the ground, 90 cm, CE ∥ AF and CE=AF , then It can be known from the calculation method of the present invention or from Table 1 that when R ₂ =30 mm, θ ₂ =44°＞γ , which meets the requirement.

The third step is to determine the minimum size of the inner diameter of the outer ring to meet the measurement requirements of the maximum plant height of wheat. When measuring 150cm high wheat, combined with Figure 6, the calculation method of the angle γ between the long pole and the horizontal plane is as follows: AB is the plant height, equal to 150cm, point C is the sensor position, BC is 50cm long, point F is the standing position of the measurement personnel, AF is the horizontal distance between the measurement personnel and the crop, 100cm, DF is the height of the position holding the long pole from the ground, 90cm, DE∥AF and DE=AF , then It can be known from the calculation method of the present invention or from Table 1 that when R ₂ =35 mm, θ ₂ = 52 °＞γ , which meets the requirement.

Taking the second and third steps into consideration, R ₂ =35mm is determined. R ₁ =25mm is determined by the first step. To facilitate the installation of the inner and outer rings, the inner diameter of the inner ring can be appropriately increased.

Embodiment 2:

The horizontal distance between the measuring person and the crop is 200 cm, and other conditions are the same as those in Example 1.

The first step is to design the inner diameter R ₁ of the inner ring. Since the rotation of the long rod does not exceed 30°, the design of R ₁ only needs to satisfy θ ₁ ≥ 30 ° . It can be seen from the calculation method of the present invention or from Table 1 that when R ₁ = 25 mm, θ ₁ = 33°＞30° , which meets the requirements.

The second step is to determine the minimum size of the inner diameter of the outer ring to meet the measurement requirements when the plant height is 1 cm. When measuring wheat with a height of 1 cm, combined with Figure 7, the calculation method of the angle γ between the long pole and the horizontal plane is as follows: AB is the plant height, equal to 1 cm, point C is the sensor position, BC is 20 cm long, point F is the standing position of the measurement personnel, AF is the horizontal distance between the measurement personnel and the crop, 200 cm, DF is the height of the position holding the long pole from the ground, 90 cm, CE∥AF and CE=AF , then It can be known from the calculation method of the present invention or from Table 1 that when R ₂ =25 mm, θ ₂ =33°＞γ , which meets the requirement.

The third step is to determine the minimum size of the inner diameter of the outer ring to meet the measurement requirements of the maximum plant height of wheat. When measuring 150cm high wheat, combined with Figure 8, the calculation method of the angle γ between the long pole and the horizontal plane is as follows: AB is the plant height, equal to 150cm, point C is the sensor position, BC is 50cm long, point F is the standing position of the measurement personnel, AF is the horizontal distance between the measurement personnel and the crop, 200cm, DF is the height of the position holding the long pole from the ground, 90cm, DE∥AF and DE=AF , then It can be known from the calculation method of the present invention or from Table 1 that when R ₂ =25 mm, θ ₂ =33°＞γ , which meets the requirement.

Taking the second and third steps into consideration, R ₂ = 25 mm is determined. R ₁ = 25 mm is determined by the first step. However, the inner diameter of the outer ring must be larger than the outer diameter of the inner ring. Therefore, in order to facilitate the installation of the inner and outer rings, the inner diameter of the outer ring needs to be appropriately increased.

Embodiment 3:

The crop sensor is used to monitor corn. The sensor has r = 40mm. The balance ring has two layers and is made of plastic or nylon. According to the requirements of aesthetics and mechanical strength, h ₁ = h ₂ = 3mm. Taking into account the variety factors and management conditions, in order to improve the applicability of the balance device, it is assumed that the maximum plant height of corn is 300cm. After the corn row is closed, the sensor is 50cm above the corn canopy during measurement, and the horizontal distance between the measurement personnel and the corn is 300cm. When the plant height is 1cm after the corn seedlings to before the row is closed, the sensor is 20cm above the corn, and the horizontal distance between the measurement personnel and the corn is 100cm. The outer ring of the balance device is equipped with a handle, which is fixed on a long pole. The measurement personnel hold the long pole for measurement. The height of the position holding the long pole from the ground is 90cm. The line connecting the two fixed points of the inner and outer rings is perpendicular to the central axis of the handle, and the rotation of the handle does not exceed 30°.

The first step is to design the inner diameter R ₁ of the inner ring. Since the rotation of the long rod does not exceed 30°, the design of R ₁ only needs to satisfy θ ₁ ≥ 30° . It can be seen from the calculation method of the present invention or from Table 1 that when R ₁ =50mm, θ ₁ =34°＞30° , which meets the requirements.

The second step is to determine the minimum size of the inner diameter of the outer ring to meet the measurement requirements when the plant height is 1 cm. When measuring 1 cm high corn, combined with Figure 9, the angle γ between the long pole and the horizontal plane is calculated as follows: AB is the plant height, equal to 1 cm, point C is the sensor position, BC is 20 cm long, point F is the standing position of the measurement personnel, AF is the horizontal distance between the measurement personnel and the crop, 100 cm, DF is the height of the position holding the long pole from the ground, 90 cm, CE∥AF and CE=AF , then It can be known from the calculation method of the present invention or from Table 1 that when R ₂ =55 mm, θ ₂ =40°＞γ , which meets the requirement.

The third step is to determine the minimum size of the inner diameter of the outer ring to meet the measurement requirements of the maximum plant height of corn. When measuring 150cm high wheat, combined with Figure 10, the calculation method of the angle γ between the long pole and the horizontal plane is as follows: AB is the plant height, equal to 300cm, point C is the sensor position, BC is 50cm long, point F is the standing position of the measurement personnel, AF is the horizontal distance between the measurement personnel and the crop, 300cm, DF is the height of the position holding the long pole from the ground, 90cm, DE∥AF and DE=AF , then It can be known from the calculation method of the present invention or from Table 1 that when R ₂ =60 mm, θ ₂ =45°＞γ , which meets the requirement.

Taking the second and third steps into consideration, R ₂ = 60 mm is determined. R ₁ = 50 mm is determined by the first step. To facilitate the installation of the inner and outer rings, the inner diameter of the inner ring can be appropriately increased.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims (8)

1. A crop growth information sensor self-balancing device, characterized in that: the balancing device is a balancing ring mounted on a sensor housing (1), the balancing ring comprising at least two layers of movably connected co-centric connecting rings, the innermost inner ring (2) is movably connected to the sensor housing (1) at both ends of the diameter, the connecting points of two adjacent connecting rings are located on the diameter of the outer connecting ring, and a handle (4) is provided on the outer wall of the outermost outer ring (3); there is at least one connecting line between the connecting points of two adjacent connecting rings, which is perpendicular to the connecting line between the inner ring and the sensor housing in a horizontal plane; the inner ring and the sensor housing are movably connected by a radial clamping column (5) on the inner wall of the inner ring, which is movably clamped with a mounting hole opened on the sensor housing; the adjacent connecting rings are movably connected by a pin shaft (6) on the inner wall of the outer connecting ring, and a connecting hole is opened on the side wall of the inner connecting ring, and the pin shaft is movably connected in the connecting hole; Design the connecting rings at each layer so that the maximum rotation angle θ is greater than or equal to the maximum pitch angle of the connecting ring during use. Where r is the radius of the sensor housing, R is the inner radius of each layer of connecting ring, and h is the distance from each layer of connecting ring to its adjacent inner layer connecting ring or the connection point of the sensor housing to the bottom edge of the connecting ring; Design method of the self-balancing device: (1) Determine the sensor model according to the crop to be tested and obtain the sensor housing radius r; determine the connection ring height H according to the requirements of mechanical strength and ease of installation; the distance from each layer of connection ring to its adjacent inner layer connection ring or the sensor housing connection point to the bottom edge of the connection ring is h; (2) Design the inner diameter R of the left-right tilting connecting ring: First, preset the maximum pitch angle γ of the connecting ring caused by the left-right rotation of the handle during use, and then calculate the inner diameter R of the left-right tilting connecting ring according to the inner diameter R of the left-right tilting connecting ring. Design R value to satisfy θ≥γ; (3) Design the inner diameter R of the front and rear tilting connecting ring: the crop height or canopy height during measurement is preset to be _hcrop , the distance of the sensor above the crop is _hmeasure , the horizontal distance between the surveyor and the crop is L, the balance ring handle is connected to the long pole, and the height of the position where the surveyor holds the long pole from the ground is _hhand . When the crop is short and the long pole is tilted downward for measurement, the inclination angle of the long pole to the horizontal plane is γ. When the crop is high and the pole is tilted upward for measurement, the inclination angle between the pole and the horizontal plane is γ. Based on this, the maximum pitch angle γ of the connecting ring in use when monitoring the minimum and maximum plant heights of crops is calculated. Design R value to satisfy θ≥γ; (4) Compare the R calculated in step (2) with that in step (3). If the R of the inner connecting ring is significantly smaller than the R of the outer connecting ring, the design dimensions of the connecting rings meet the requirements, or the R of the inner connecting ring can be appropriately increased for ease of installation. If the R of the inner connecting ring is greater than or equal to or slightly smaller than the R of the outer connecting ring, resulting in the inability to install, the R of the outer connecting ring can be appropriately increased. 2. A crop growth information sensor self-balancing device according to claim 1, characterized in that: the clamping column (5) is cylindrical and has a hemispherical top. 3. A crop growth information sensor self-balancing device according to claim 1, characterized in that a friction surface is provided on the outer surface of the clamping column and/or the inner surface of the mounting hole. 4. A crop growth information sensor self-balancing device according to claim 1, characterized in that the connection point between each layer of connecting ring and its adjacent inner layer connecting ring or sensor housing is located at the center of the height of the connecting ring. 5. A crop growth information sensor self-balancing device according to claim 1, characterized in that the height of the connecting ring is 2 to 50 mm. 6. A crop growth information sensor self-balancing device according to claim 1, characterized in that the movable connection point between the inner ring and the sensor housing is located within the upper third of the sensor. 7. A crop growth information sensor self-balancing device according to claim 1, characterized in that when the axis of the sensor is vertical and the inner and outer balance rings are horizontal, the axis of the handle is on the extension line of the connection line between the inner ring and the sensor housing connection point. 8. A method for designing the self-balancing device according to claim 1, characterized in that: (1) Determine the sensor model according to the crop to be tested and obtain the sensor housing radius r; determine the connection ring height H according to the requirements of mechanical strength and ease of installation; the distance from each layer of connection ring to its adjacent inner layer connection ring or the sensor housing connection point to the bottom edge of the connection ring is h; (2) Design the inner diameter R of the left-right tilting connecting ring: First, preset the maximum pitch angle γ of the connecting ring caused by the left-right rotation of the handle during use, and then calculate the inner diameter R of the left-right tilting connecting ring according to the inner diameter R of the left-right tilting connecting ring. Design R value to satisfy θ≥γ; (3) Design the inner diameter R of the front and rear tilting connecting ring: the crop height or canopy height during measurement is preset to be _hcrop , the distance of the sensor above the crop is _hmeasure , the horizontal distance between the surveyor and the crop is L, the balance ring handle is connected to the long pole, and the height of the position where the surveyor holds the long pole from the ground is _hhand . When the crop is short and the long pole is tilted downward for measurement, the inclination angle of the long pole to the horizontal plane is γ. When the crop is high and the pole is tilted upward for measurement, the inclination angle between the pole and the horizontal plane is γ. Based on this, the maximum pitch angle γ of the connecting ring in use when monitoring the minimum and maximum plant heights of crops is calculated. Design R value to satisfy θ≥γ; (4) Compare the R calculated in step (2) with that in step (3). If the R of the inner connecting ring is significantly smaller than the R of the outer connecting ring, the design dimensions of the connecting rings meet the requirements, or the R of the inner connecting ring can be appropriately increased for ease of installation. If the R of the inner connecting ring is greater than or equal to or slightly smaller than the R of the outer connecting ring, resulting in the inability to install, the R of the outer connecting ring can be appropriately increased.