Walnut picking machine based on aerodynamic excitation coupling and control method

Abstract

This application relates to a pneumatically vibrating coupled walnut harvester. The pneumatically vibrating coupled walnut harvester has a spring-holding mechanism installed at the front end of a reciprocating impact head. A vibration mechanism is installed inside the reciprocating impact head. A harvesting rod connects the reciprocating impact head to an air compressor. The air compressor is connected to the vibration mechanism via an air connection pipe, and a gasoline generator is connected to the air compressor. A flow control system connects and controls the vibration mechanism, air compressor, and gasoline generator. The solution provided in this application uses compressed air generated by the air compressor to drive the vibration mechanism, which in turn excites the reciprocating impact head to vibrate the branches of ripe walnuts. By coordinating the flow control system and vibration sensor data, the airflow of the vibration mechanism is adjusted to ensure that the vibration frequency and force of the reciprocating impact head meet the optimal harvesting vibration intensity for ripe walnut branches, thereby improving the harvesting efficiency of ripe walnuts.

Description

Technical Field

[0001] This application relates to the field of walnut harvesting technology, and in particular to a walnut harvesting machine and control method based on pneumatic vibration coupling. Background Technology

[0002] Existing walnut harvesting machinery is constrained by terrain, making it difficult to adapt to complex terrain and narrow spaces, thus failing to fully realize its potential.

[0003] Furthermore, the currently developed portable gasoline engine-driven walnut harvesting machines have short operating times, low energy efficiency, and are only suitable for harvesting single branches. Repeated harvesting can damage the fruit-bearing branches, making it difficult to harvest the fruit from thicker branches. Therefore, walnut trees with thicker fruit-bearing branches still require manual harvesting, which raises concerns about personnel safety and reduces harvesting efficiency. There are also methods that involve shaking or banging the trunk to knock the nuts off the branches, but these devices are not easy to operate, are inconvenient to move, and are relatively expensive. In addition, most mountain walnut trees are large and cannot be harvested properly, so manual harvesting by climbing trees remains the primary method. Summary of the Invention

[0004] To address or partially address the problems existing in related technologies, this application provides a pneumatically vibrating coupled walnut harvester and its control method. This pneumatically vibrating coupled walnut harvester and its control method can drive a vibration mechanism to excite a reciprocating impact head to vibrate the branches of ripe walnuts by using compressed air generated by an air compressor. In conjunction with a flow control system and vibration sensor data detection, the air flow of the vibration mechanism is adjusted so that the vibration frequency and force of the reciprocating impact head meet the optimal harvesting vibration intensity for ripe walnut branches. This improves the harvesting efficiency of ripe walnuts and reduces the energy consumption required for walnut harvesting, achieving efficient and low-cost harvesting of ripe walnuts from branches and avoiding safety accidents caused by manual tree climbing harvesting.

[0005] The first aspect of this application provides a walnut harvesting machine based on pneumatic vibration coupling, comprising:

[0006] Reciprocating impact head, spring holding mechanism, vibration mechanism, picking rod, hand grip, air connection pipe, flow control system, air compressor and gasoline generator;

[0007] The spring holding mechanism is installed at the front end of the reciprocating impact head, and the excitation mechanism is installed inside the reciprocating impact head to excite the vibration of the reciprocating impact head. One end of the picking rod is installed at the rear end of the reciprocating impact head, and the other end of the picking rod is installed with an air compressor. A hand grip is installed at the lower end of the picking rod. The air compressor is connected to the excitation mechanism through an air circuit connection pipe. The gasoline generator is connected to the air compressor.

[0008] The flow control system connects and controls the vibration excitation mechanism, air compressor, and gasoline generator;

[0009] The vibration excitation mechanism includes an eccentric wheel, a pneumatic motor, and a proportional pneumatic throttle valve. The air circuit connection pipe is connected to the air inlet of the proportional pneumatic throttle valve, and the exhaust port of the proportional pneumatic throttle valve is connected to the pneumatic motor. The eccentric wheel is mounted on the pneumatic motor, and vibration is generated by the rotation of the eccentric wheel.

[0010] Optionally, in some embodiments of the first aspect, the reciprocating impact head includes:

[0011] The machine head includes a spring mounting slot, a bearing mounting slot, a deep groove ball bearing, a pneumatic motor mounting slot, and a proportional pneumatic throttle valve mounting slot. The spring mounting slot is located on the front upper side of the reciprocating impact head. The bearing mounting slot is located on the rear upper side of the inside of the reciprocating impact head housing. Deep groove ball bearings are installed at both ends of the bearing mounting slot. The pneumatic motor mounting slot is located below the bearing mounting slot. The proportional pneumatic throttle valve mounting slot is located to the left of the pneumatic motor mounting slot.

[0012] Optionally, in some embodiments of the first aspect, the spring-loaded holding mechanism includes:

[0013] The compression spring, slide bar, and clamp are mounted on the slide bar. The compression spring is installed in the spring mounting slot, the slide bar is installed at the rear end of the compression spring, and the clamp is installed on the slide bar.

[0014] Optionally, in some embodiments of the first aspect, the air compressor is provided with an air storage tank, and an air connection pipe is connected to the air outlet of the air storage tank.

[0015] Optionally, in some embodiments of the first aspect, the flow control system includes:

[0016] The vibration sensor is mounted on the clamp head of the spring clamping mechanism. The vibration sensor transmits the detected data to the controller, which controls the airflow of the proportional pneumatic throttle valve based on the detected signal.

[0017] The controller is also connected to the air compressor and the gasoline generator, controlling the start and stop of the air compressor and supplying compressed air.

[0018] Optionally, in some embodiments of the first aspect, a quick-connect fitting is provided on the exhaust port of the proportional pneumatic throttle valve, and the air connection pipe is installed on the exhaust port of the proportional pneumatic throttle valve through the quick-connect fitting.

[0019] Optionally, in some embodiments of the first aspect, the gas storage tank is equipped with a pressure gauge connected to a controller. When the air in the tank is insufficient, the controller controls the gasoline generator to drive the air compressor to supplement compressed air.

[0020] The second aspect of this application provides a control method for a pneumatically excited coupled walnut harvester, including:

[0021] The reciprocating impact head is secured to the mature walnut branches, and the walnut harvester is started at the default frequency.

[0022] It receives vibration signals detected by vibration sensors and predicts the natural frequency of branches using a convolutional neural network model;

[0023] The required airflow for the pneumatic motor is calculated based on the predicted natural frequency of the branches. The flow ratio of the proportional pneumatic throttle valve is adjusted using an electrical signal to control the opening of the proportional pneumatic throttle valve, thereby regulating the airflow.

[0024] By monitoring the vibration frequency detected by the vibration sensor, the flow rate ratio of the proportional pneumatic throttle valve is continuously fine-tuned to ensure that the mature walnut branches reach the expected stable resonance frequency.

[0025] The technical solution provided in this application may include the following beneficial effects:

[0026] This application uses compressed air generated by an air compressor to drive a vibration mechanism that excites a reciprocating impact head to vibrate the branches of ripe walnut trees. In conjunction with a flow control system and vibration sensor data detection, the airflow of the vibration mechanism is adjusted to ensure that the vibration frequency and force of the reciprocating impact head meet the optimal harvesting vibration intensity for ripe walnut branches. This improves the harvesting efficiency of ripe walnuts and reduces the energy consumption required for walnut harvesting, achieving efficient and low-cost harvesting of ripe walnuts from branches and avoiding safety accidents caused by manual tree climbing for harvesting.

[0027] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0028] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0029] Figure 1 This is a schematic diagram of the structure of a pneumatically excited coupled walnut harvester shown in the embodiments of this application;

[0030] Figure 2 This is another structural schematic diagram of a pneumatically excited coupled walnut harvester shown in an embodiment of this application;

[0031] Figure 3 This is a schematic diagram of the excitation mechanism structure of a pneumatically coupled walnut harvester as shown in the embodiments of this application;

[0032] Figure 4 This is a schematic diagram of the flow control system structure of a pneumatically excited coupled walnut harvester shown in an embodiment of this application;

[0033] Figure 5 This is a schematic diagram illustrating the principle of the flow control system based on a pneumatically excited coupled walnut harvester, as shown in an embodiment of this application.

[0034] Reference numerals: 1-Reciprocating impact head; 2-Spring holding mechanism; 3-Vibration sensor; 4-Vibration excitation mechanism; 5-Harvesting rod; 6-Handheld handle; 7-Air connection pipe; 8-Flow control system; 9-Air tank; 10-Air compressor; 11-Gas generator; 12-Spring mounting slot; 13-Bearing mounting slot; 14-Pneumatic motor mounting slot; 15-Proportional pneumatic throttle valve mounting slot; 16-Compression spring; 17-Slide rod; 18-Clipper; 19-Deep groove ball bearing; 20-Eccentric wheel; 21-Pneumatic motor; 22-Proportional pneumatic throttle valve; 23-Quick connector; 24-Connecting cable; 25-Controller. Detailed Implementation

[0035] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0036] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0037] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0038] Unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0039] The current method of harvesting walnuts by manually climbing trees and using bamboo poles is inefficient and unsafe, resulting in high harvesting costs for fresh walnuts and seriously affecting the yield and quality of walnuts. It also restricts the development of Yunnan's walnut industry. Manual tree climbing for harvesting can lead to physical exhaustion due to high-intensity, high-load work at heights, and is prone to safety accidents.

[0040] Furthermore, the currently developed portable gasoline engine-driven walnut harvesting machines have short operating times, low energy efficiency, and are only suitable for harvesting single branches. Repeated harvesting can damage the fruit-bearing branches, making it difficult to harvest the fruit from thicker branches. Therefore, walnut trees with thicker fruit-bearing branches still require manual harvesting, which raises concerns about personnel safety and reduces harvesting efficiency. There are also methods that involve shaking or banging the trunk to knock the nuts off the branches, but these devices are not easy to operate, are inconvenient to move, and are relatively expensive. In addition, most mountain walnut trees are large and cannot be harvested properly, so manual harvesting by climbing trees remains the primary method.

[0041] To address the aforementioned issues, this application provides a pneumatically driven vibration-coupled walnut harvester and its control method. The method utilizes compressed air generated by an air compressor to drive a vibration mechanism that excites a reciprocating impact head to vibrate the branches of ripe walnuts. By coordinating a flow control system and vibration sensor data, the airflow of the vibration mechanism is adjusted to ensure the reciprocating impact head's vibration frequency and intensity meet the optimal harvesting vibration requirements for ripe walnut branches. This improves the harvesting efficiency of ripe walnuts and reduces the energy consumption required for harvesting, achieving efficient and low-cost harvesting of ripe walnuts from branches and avoiding safety accidents caused by manual tree climbing.

[0042] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0043] Figure 1 This is a schematic diagram of the structure of a pneumatically excited coupled walnut harvester shown in an embodiment of this application.

[0044] See Figure 1A walnut harvester based on pneumatic vibration coupling includes a reciprocating impact head 1, a spring holding mechanism 2, a vibration sensor 3, a vibration mechanism 4, a harvesting rod 5, a hand grip 6, an air connection pipe 7, a flow control system 8, an air tank 9, an air compressor 10, a gasoline generator 11, a spring mounting slot 12, a bearing fixing slot 13, a pneumatic motor fixing slot 14, a proportional pneumatic throttle valve fixing slot 15, a compression spring 16, a slide rod 17, a clamp 18, a deep groove ball bearing 19, an eccentric wheel 20, a pneumatic motor 21, a proportional pneumatic throttle valve 22, a quick-connect connector 23, a connecting cable 24, and a controller 25.

[0045] like Figure 2 , Figure 3 As shown, the spring mounting slot 12 is located on the upper left side of the reciprocating impact head 1. The spring holding mechanism 2 is installed at the front end of the reciprocating impact head 1. The spring holding mechanism 2 includes a compression spring 16, a slide rod 17, and a clamping head 18. The compression spring 16 is installed in the spring mounting slot 12, the slide rod 17 is fitted onto the rear end of the compression spring 16, and the clamping head 18 is installed on the slide rod 17. The elasticity of the compression spring 16 allows the clamping head 18 to hold the tree branch. A vibration sensor 3 is attached and fixed to the clamping head 18, which provides the vibration signal of the reciprocating impact head 1 to the flow control system 8 via the connecting cable 24.

[0046] The reciprocating impact head 1 has a bearing fixing groove 13 on the upper rear side inside the housing. Deep groove ball bearings 19 are installed at the upper and lower ends of the bearing fixing groove 13. A pneumatic motor fixing groove 14 is provided below the bearing fixing groove 13. A proportional pneumatic throttle valve fixing groove 15 is provided on the left side of the pneumatic motor fixing groove 14.

[0047] The excitation mechanism 4 is installed inside the reciprocating impact head 1 and is used to vibrate the reciprocating impact head 1. The excitation mechanism 4 includes an eccentric wheel 20, a pneumatic motor 21, and a proportional pneumatic throttle valve 22. The air connection pipe 7 is connected to the air inlet of the proportional pneumatic throttle valve 22. A quick-connect connector 23 is provided on the exhaust port of the proportional pneumatic throttle valve 22. The air connection pipe 7 is installed on the exhaust port of the proportional pneumatic throttle valve 22 through the quick-connect connector 23. The exhaust port of the proportional pneumatic throttle valve 22 is connected to the pneumatic motor 21. The proportional pneumatic throttle valve 22 is installed in the proportional pneumatic throttle valve fixing groove 15. The eccentric wheel 20 is installed on a deep groove ball bearing 19 in the bearing fixing groove 13. The lower end of the eccentric wheel 20 is connected to the pneumatic motor 21. The pneumatic motor 21 is installed in the pneumatic motor fixing groove 14 and is connected to the proportional pneumatic throttle valve 22 through the air connection pipe 7. The airflow is controlled by the proportional pneumatic throttle valve 22 to drive the pneumatic motor 21, which in turn drives the eccentric wheel 20 to rotate, thereby generating vibration.

[0048] See Figure 4One end of the harvesting pole 5 is installed at the rear end of the reciprocating impact head 1, and the other end is installed on the air compressor 10. The harvesting pole 5 is a multi-section bamboo or wooden pole that can be assembled, and can be adjusted according to the height of the walnut tree to be harvested. A hand handle 6 is installed at the lower end of the harvesting pole 5, and the operator can adjust the direction of the harvesting pole 5 by holding the hand handle 6.

[0049] An air compressor 10 is equipped with an air tank 9, which has a pressure gauge connected to a controller 25. When the air in the tank is insufficient, the controller 25 controls the gasoline generator 11 to drive the air compressor 10 to replenish the compressed air. An air connection pipe 7 is connected to the air outlet of the air tank 9. The air compressor 10 is connected to the vibration mechanism 4 via the air connection pipe 7, and the gasoline generator 11 is connected to the air compressor 10 via a connecting cable 24 for power supply.

[0050] See Figure 5 The flow control system 8 connects to the control excitation mechanism 4, the air compressor 10, and the gasoline generator 11. The flow control system 8 includes a vibration sensor 3 and a controller 25. The vibration sensor 3 is mounted on the clamping head 18 of the spring clamping mechanism 2. The vibration sensor 3 transmits the vibration data of the reciprocating impact head 1 to the controller 25. Upon receiving the signal, the controller 25 of the flow control system 8 calculates the natural frequency of the branches based on the natural modal frequency formula. By controlling the air pressure signal of the pneumatic actuator of the proportional pneumatic throttle valve 22, the valve opening can be adjusted, thereby controlling the airflow and changing the vibration intensity of the reciprocating impact head 1, shaking down the mature walnut fruits hanging on the branches, achieving efficient and low-cost harvesting of mature walnuts.

[0051] The controller 25 is also connected to the air compressor 10 and the gasoline generator 11 via a connecting cable 24. It controls the power and start / stop of the air compressor 10 via a frequency converter to supply compressed air. The controller 25 controls the start / stop of the gasoline generator 11.

[0052] Corresponding to the aforementioned application device embodiments, this application also provides a control method and corresponding embodiments based on a pneumatically excited coupled walnut harvester, including:

[0053] Secure the reciprocating impact head 1 to the mature walnut branch and start the walnut harvester at the default frequency.

[0054] The vibration signal detected by vibration sensor 3 is received, and the natural frequency of the branch is predicted by a BP neural network model. The BP neural network model is learned by using a large amount of initial vibration frequency data and branch resonance data of mature walnut tree branches, and a prediction model of the resonance frequency of mature walnut tree branches is obtained.

[0055] The required airflow for the pneumatic motor 21 is calculated based on the predicted natural frequency of the branch. The flow rate ratio of the proportional pneumatic throttle valve 22 is adjusted using an electrical signal to control its opening, thereby regulating the airflow. The calculation process for the required airflow for the pneumatic motor 21 based on the predicted natural frequency of the branch is as follows: vibration frequency = 60... The rotational speed / number of poles gives the rotational speed of pneumatic motor 21. Based on the rotational speed, the power of pneumatic motor 21 is calculated: power (kW) = torque (Nm). Rotational speed (rpm) / 9549. Finally, based on the power of the pneumatic motor 21, the required airflow is obtained. The power N of the pneumatic motor 21 = the pressure P of the compressed air. Traffic Q.

[0056] By monitoring the vibration frequency detected by the vibration sensor 3, when the calculated air flow rate Q of the proportional pneumatic throttle valve 22 is insufficient to make the branches resonate, the flow rate ratio of the proportional pneumatic throttle valve 22 is continuously fine-tuned so that the mature walnut branches reach the expected stable resonance frequency.

[0057] The pneumatically driven, vibration-coupled walnut harvester provided in this application, after the complete walnut harvester is installed, connected, fixed, and debugged, checks are performed to ensure that the gasoline generator 11 and air compressor 10 are in normal working order, and the installation of the connecting cable 24 and the air circuit connecting pipe 7 is checked. The operator places the air compressor 10 and gasoline generator 11 under the walnut tree and starts the gasoline generator 11 and air compressor 10 to fill the air tank 9. The operator holds the harvesting pole 5 and clamps the reciprocating impact head 1 onto the mature walnut branch, opens the air tank 9 switch, and the reciprocating impact head 1 causes the branch to vibrate. The vibration sensor 3 transmits the detected vibration information to the flow control system 8, which controls the excitation force of the reciprocating impact head 1, thereby achieving the harvesting of mature walnut fruits hanging on the branch.

[0058] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A walnut harvester based on pneumatic vibration coupling, characterized in that, include: Reciprocating impact head (1), spring holding mechanism (2), vibration mechanism (4), picking rod (5), hand grip (6), air connection pipe (7), flow control system (8), air compressor (10) and gasoline generator (11). The spring holding mechanism (2) is installed at the front end of the reciprocating impact head (1), the vibration excitation mechanism (4) is installed inside the reciprocating impact head (1) to excite the vibration of the reciprocating impact head (1), one end of the picking rod (5) is installed at the rear end of the reciprocating impact head (1), and the other end of the picking rod (5) is equipped with an air compressor (10). The hand grip (6) is installed at the lower end of the picking rod (5). The reciprocating impact head (1) includes: a spring mounting groove (12), a bearing fixing groove (13), and a deep groove ball bearing. (19) Pneumatic motor mounting slot (14) and proportional pneumatic throttle valve mounting slot (15), the spring mounting slot (12) is located on the front side of the upper end of the reciprocating impact head (1), the upper rear side of the reciprocating impact head (1) housing is provided with a bearing mounting slot (13), deep groove ball bearings (19) are installed at the upper and lower ends of the bearing mounting slot (13), a pneumatic motor mounting slot (14) is provided below the bearing mounting slot (13), and a proportional pneumatic throttle valve mounting slot (15) is provided on the left side of the pneumatic motor mounting slot (14). The air compressor (10) is connected to the excitation mechanism (4) through the air circuit connection pipe (7); the gasoline generator (11) is connected to the air compressor (10). The flow control system (8) is connected to the control excitation mechanism (4), the air compressor (10), and the gasoline generator (11); the flow control system (8) includes: a vibration sensor (3) and a controller (25). The vibration sensor (3) is installed on the clamp head (18) of the spring clamping mechanism (2). The vibration sensor (3) transmits the detection data to the controller (25). The controller (25) controls the air flow of the proportional pneumatic throttle valve (22) according to the detection signal. The controller (25) is also connected to the air compressor (10) and the gasoline generator (11) to control the start and stop of the air compressor (10) and to supply compressed air. The excitation mechanism (4) includes an eccentric wheel (20), a pneumatic motor (21) and a proportional pneumatic throttle valve (22). The air passage connecting pipe (7) is connected to the air inlet of the proportional pneumatic throttle valve (22), and the exhaust port of the proportional pneumatic throttle valve (22) is connected to the pneumatic motor (21). The eccentric wheel (20) is mounted on the pneumatic motor (21), and vibration is generated by the rotation of the eccentric wheel (20).

2. The walnut harvester based on pneumatic vibration coupling according to claim 1, characterized in that, The spring-loaded holding mechanism (2) includes: Compression spring (16), slide bar (17) and clamp (18) are provided. The compression spring (16) is installed in the spring mounting groove (12), the slide bar (17) is installed at the rear end of the compression spring (16), and the clamp (18) is installed on the slide bar (17).

3. The walnut harvester based on pneumatic vibration coupling according to claim 1, characterized in that: The air compressor (10) is equipped with an air storage tank (9), and the air connection pipe (7) is connected to the air outlet of the air storage tank (9).

4. The walnut harvester based on pneumatic vibration coupling according to claim 3, characterized in that: The proportional pneumatic throttle valve (22) is provided with a quick-connect fitting (23) at its exhaust port, and the air circuit connecting pipe (7) is installed on the exhaust port of the proportional pneumatic throttle valve (22) through the quick-connect fitting (23).

5. The walnut harvester based on pneumatic vibration coupling according to claim 4, characterized in that: The gas storage tank (9) is equipped with a pressure gauge, which is connected to a controller (25). When there is insufficient air in the tank, the controller (25) controls the gasoline generator (11) to drive the air compressor (10) to replenish the compressed air.

6. A control method for a pneumatically excited coupled walnut harvester, applied to the pneumatically excited coupled walnut harvester as described in any one of claims 1-5, characterized in that, include: The reciprocating impact head (1) is clamped onto the mature walnut hanging branch and the walnut harvester is started at the default frequency. The vibration signal detected by the vibration sensor (3) is received, and the natural frequency of the branch is predicted by the convolutional neural network model; The required airflow of the pneumatic motor (21) is calculated based on the predicted natural frequency of the branch. The flow ratio of the proportional pneumatic throttle valve (22) is adjusted using an electrical signal to control the opening of the proportional pneumatic throttle valve (22) and thus adjust the airflow. By monitoring the vibration frequency detected by the vibration sensor (3), the flow rate ratio of the proportional pneumatic throttle valve (22) is continuously fine-tuned so that the mature walnut branches reach the expected stable resonance frequency.

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